PART II

EVERYDAY MACHINES

I

SOME PRACTICAL ADVICE

Some of our inventions and some of our discoveries are of comparatively

recent date, but most of them had their beginnings centuries before

historical times, as many of our greatest inventions are the result of

gradual growth and development. The early discovery, by some unknown

persons or persons, of the making of bronze and the hardening of it, led

up to stone and woodcutting, perhaps to the breaking-up and smelting of

iron ore, and the extraction of the metals. This again opened the way for

the making of steel, a discovery that placed in the hands of man a source

of power which enabled him to overcome many natural difficulties. One

improvement led the way to another, and made other improvements possible.

Take locomotives and steamboats for instance. The making of a raft, no

doubt, suggested the canoe, and this led to the built-up boat, and the

ship. The paddle and the oar doubtless led up to the sidewheeler, and

the scull to the propeller. The crude steam engine of Hero very likely

suggested the steam engines now in use, and this new power rendered it

easy for Stephenson and Fulton to perform their work; but, if either

of these inventors were to come back to the earth and examine the great

steamers of to-day, or the perfect and powerful locomotives now in use,

they would be surprised to think that the present tractable monsters, were

the outgrowth of their early efforts.

In the same manner may be traced the same gradual growth in all the

arts and sciences; for step by step, in every department of life, have

completeness and perfection come to us. It is not yet one hundred years

since Congreve invented or rather completed the invention of the "Parlor

match," called in his day, the "Lucifer match." This grand achievement

was accomplished after many failures in the efforts of chemists for ages.

The perfection of the match was a great blessing to humanity, as the old

methods of making a light or fire were tiresome and very uncertain. So it

is with many of the blessings we enjoy to-day: they are simply the results

of the struggles of many unknown minds, the threads of which were gathered

up and pieced together by one master mind, so as to be made useful and

profitable to mankind.

In the early and middle ages, the inventor was looked upon as a wizard, a

sort of inferior demon, or, at best, an uncanny kind of man, and a proper

subject for the stake. When, by superior wisdom and skill, he invented

some machine or device, or discovered some new and better method of

accomplishing a useful end, he was at once looked upon as a necromancer

in league with his Satanic majesty, and, therefore, unfit to associate

with or be recognized as a Christian. History records many instances of

inventors and progressive men being persecuted--and executed--because of

their having discovered or invented something which would interfere with

some vested or imaginary rights. The new inventions must be destroyed or

put away out of sight and hearing, and the most powerful influences were

employed to bring about this result. The stories told of Friar Bacon,

Papin, Crompton, and hundreds of other inventors, give us a few of the

reasons why so little progress was made in the arts and sciences previous

to the sixteenth century.

Down to a period within the past few years the term invention has been

considered almost synonymous with the word chance. An inventor, was a

lucky individual, who had happened to hit upon some new idea, not so much

by his own great ability as by good fortune, similar to that which brings

success to the purchaser of a lottery ticket.

In many cases this was really the true state of affairs. Men who

experimented in various mechanical pursuits often stumbled upon results,

which they perceived to be useful and valuable, and, if they protected

the invention by patent, they often became wealthy.

At the present time this meaning of the word invention must be greatly

modified, if not altogether abandoned. The law which controls the action

of the forces of nature is becoming so well understood among all classes

of mechanics that chance invention, in the early sense of the term, has

almost become an impossibility. Success can be assured only to the man

who has tried to win it by the acquirement of the necessary knowledge,

to be obtained by steady application and hard study. In the pursuit of

discovery, the old saying, "knowledge is power," never has had more force

than when applied to unravelling the tangled web of nature's mysteries.

"Science," says Lord Brougham, "is knowledge reduced to a system."

A man may have a lifetime of practical experience and amass a fund of

knowledge of great use to himself, but entirely unavailable for others.

But if his experience be combined with that of other men and systematized

into a regular order, it becomes part of the science of that branch of

industry, and although the person himself may have a profound contempt

for science and theory his work may be quite scientific.

Ignorance, in the past centuries, was another great factor in preventing

mechanical progress. New machines and labour-saving devices were looked

upon by the great mass of workers as contrivances designed to deprive them

of the means of making an honest livelihood, and this point of view caused

the people to smash and burn many machines that had cost great labour and

expense to the unfortunate inventor. But, as public schools became more

numerous and learning increased, the way of the inventor became smoother.

The more enlightened nations encouraged inventors and inventions, and

now our country has on its statute books laws for this purpose, the most

liberal in the world.

The opportunities for obtaining mechanical and scientific knowledge and

technical instruction are now so many and so easy of access that inventors

have but little trouble in acquiring the data and facts essential to their

purposes. The earliest students had nothing but their own observations

and experiences to build on, and even as late as the eighteenth century,

men had to grope in the dark for the data required to carry out their

ideas. A brief examination of the early treatises on mechanics and the

rude illustrations in the works of Leopold, Amoutons, and Desaguliers will

reveal the germs of many modern machines.

The inventor of to-day, however, must proceed by a different path from

his predecessor, if he expects to succeed in the present advanced state

of mechanical arts. The demonstration of the mechanical equivalent of

heat, the discovery of the correlation of the physical forces, and the

development of the sciences of thermo-dynamics have furnished powerful

weapons for the advancement of mechanical science, and he who does not

use them is at a woeful disadvantage in the fight. There is no "royal

road" to success for the inventor, and I hope you will always bear this

in mind when attending to your studies, for you must remember that it is

nearly always necessary to use formulæ and symbols to express relations,

which are hardly within the range of words, and often a combination of

data obtained from different sources may be used to derive entirely new

relations.

It is here that invention, in the modern sense of the term, comes in

to hold a place midway between theory and practice, and may be properly

called a science.

THE LAWS OF GRAVITATION

Suppose a one-pound weight is suspended by a string: there is a tensile

stress in the string, varying slightly at different parts of the earth,

but always the same at the same place, say, Newark, for the variation is

very slight within a pretty wide area. If we take a spring balance and

graduate it in pounds at Newark, such a balance will accurately indicate

forces in pounds wherever it may be used. The stress produced in a string

carrying a one-pound weight at Newark is the unit of force. If the string

with its weight is hung from a nail, the nail is pressed on its upper side

with a force of one pound. The same pressure may be produced by pushing

the nail downwards from above, using a short piece of stick; in such

circumstances, the stick bears a compression stress of one pound. This

is a good, common-sense definition of force, though it does not by any

means cover the whole subject. The word force is used in a different sense

by persons who speak of the force of gravity. When a one-pound weight is

suspended by a string, as stated in the foregoing, the attraction between

the mass of the weight and the mass of the earth is balanced by the stress

in the string. We can double the stress by doubling the weight, and in

this way, by adding weights, we can make the force of gravity very great.

But the force of gravity is spoken of as an invariable thing, and it is

said to be equal to 32 (roughly). If any weight whatever be allowed to

fall freely (for reasonable heights and neglecting the effect of the

resistance of the air) it will be found that at the end of the first

second it will have a velocity of 32 feet per second; at the end of the

second second it will have a velocity of 64 feet per second; and generally

at the end of any number of seconds its velocity will be 32, and the

rate of increase of velocity (acceleration) is 32 feet per second, all of

which has been previously explained. It is found convenient to call this

acceleration gravity--it is inaccurately called the force of gravity,

it varies at different places on the earth. It is usual to designate the

acceleration by the letter g, and we speak of the g, or gravity, of the

place. This seems to cover the point of inquiry completely.

The subject of specific gravity is a far-reaching one, and includes

the testing of liquors for revenue purposes and many other things of a

scientific nature; but when we speak of specific gravity in an ordinary

way we mean the comparative weight, bulk for bulk, of water at a certain

temperature. The specific gravity of a substance like coal can be

ascertained experimentally. By means of a specially adapted and delicate

balance, the sample of coal is first weighed in the ordinary way, after

which it must be weighed suspended in a vessel of water. Weighed in water,

it will be found the coal does not weigh so much. If the loss of weight,

or the difference between the first and second weighings be taken, and

the first weighing divided by this loss of weight, we obtain the specific

gravity of coal. For example, suppose a sample of coal weighs in the

ordinary way 20 ounces, and in the water only four ounces, showing a loss

of weight of 16 ounces. Divide 20 by 16, and we get the specific gravity

of the sample of coal, viz., 1.25.

The use of specific gravity is of great importance in mining, with regard

to analysis of the minerals worked, for with a class of coal having the

same relative composition, qualities, and calorific power per ton of coal

employed for different purposes, yet having a higher specific gravity, the

room required for storage or transport will be less. This is an important

factor, where there is limited space, as in depots and naval vessels.

It is also employed in the arts and industries for many purposes, and

is particularly useful to workers in precious metals, as the amount of

alloy or baser metal may be determined by it that have been used in the

manufacture of jewellery, plate, and similar articles.

To put it briefly: Specific gravity is the ratio of the heaviness of any

substance to that of water. The specific gravity of water is taken as

unity, and that of any other substance is expressed as a decimal. Tables

of the weight and specific gravity of substances can be found in any good

hand-book of engineering.

HOW TO ADJUST SEWING MACHINES.

Sewing machines often get out of order, and it is not always that an

expert is at hand to adjust them, so a few general observations on the

subject of these household machines may prove useful and interesting to

every one who is at all mechanically inclined.

There are several distinct types of machines, but we shall confine our

remarks to the Singer vibrating shuttle, the hook shuttle types, and

one or two others. To secure a perfect stitch in the vibrating shuttle

machine, and to keep it from puckering thin goods, such as Japanese

silks, muslins, and voiles, though possible, is difficult. Success depends

entirely on the careful fitting of parts and the skilful adjustment of the

machine to the particular fabric. In the first place, it is essential that

a machine should work quite freely, a point not of such great importance

if it is used for rougher classes of work.

Machines used for domestic purposes, like the V. S. (vibrating shuttle),

often stand unused for weeks together, so that the oil thickens and makes

a machine run somewhat heavily and unevenly. This may indirectly affect

the regularity of the tension, especially with thin goods. Therefore, it

is important to keep a machine clean and regularly oiled. Important parts

are often overlooked during the operation; in fact, many users of machines

do not know how nor where to oil one properly. Therefore Figs. 79 and 80

will be helpful, as they show the location of oil holes and parts to be

oiled, and the illustrations will serve as a guide to other machines. In

these figures, it will be seen that there are a number of parts to oil

which could very easily be overlooked. When a machine has been unworked

for a length of time, the application of a little paraffin will cleanse

the parts which should afterwards be oiled thoroughly with a good quality

of machine oil. The shuttle raceway, where the shuttle works, should be

wiped out with an oily rag. Any lint or dirt which has accumulated inside

the shuttle at the nose end should be withdrawn, as such might retard

the unwinding of the bobbin. It is imperative that the cotton should pull

evenly, that is, free from jerks; this refers to the upper as well as to

the lower tension.

[Illustration: Fig. 79. Section showing oil holes]

For silk and similar materials, best results can be obtained if fine

cottons are used. Numbers 60, 70, or 80 would be preferable to No. 40.

A good quality of fine silk is even better. It must be remembered that

when working on thin silk, say two thicknesses, a coarse cotton cannot be

locked centrally. Fine cotton will need a fine needle, which necessitates

a fine hole needle plate.

[Illustration: Fig. 80. Action of shuttle in the race]

If, after the foregoing points have been attended to, the machine runs

easily, the parts fit properly, there is no end play to the upper shaft

and the cottons pull evenly, yet the tensions are erratic, attention

should be given to the loop as it draws off the shuttle heel. In machines

of the C. B., O. S., and especially the V. S. class, there is a tendency

for the loop to hang on the heel of the carrier, or to become trapped

between the shuttle and the carrier heel. In the two former types of

machines, the heel of the carrier should be rounded so as to induce the

cotton to pass off as freely as possible. Sometimes it is necessary to

time the shuttle a little later, that is, put the carrier back a little

to allow the loop to draw off more in a line with the hole in the needle

plate.

In V. S. machines the carrier is already rounded off at the heel. By

referring to Fig. 80, the action of the shuttle in the raceway can be

seen, which is from A to B. The shuttle, having just entered the loop, is

about to move to B. This movement can be regulated by an eccentric screw

and nut (Fig. 80). When a machine has been taken to pieces and cleaned,

this screw is not always replaced to the best advantage. If the shuttle

moves too much toward B, the loop is carried by the heel of the carrier,

and, at the same time, the shuttle cotton, by bearing tightly on the

needle plate, pulls the shuttle toward the carrier heel, thus making it

difficult for the loop to release itself. More tension is applied, perhaps

more pressure is put on the take-up spring, yet the uneven tension is

not overcome, and owing to the softness of the fabric, it is drawn up or

puckered. The remedy is to turn the screw C (Fig. 80), until the carrier

is in a position to allow the loop a free exit.

For such soft materials as mentioned it may be necessary to slacken both

tensions. It should be remembered that the upper tension is generally

somewhat tighter than the under one, and this should be a guide to the

adjustment of the latter, according to the fabrics to be stitched.

To prevent puckering when the tensions are correct, reduce the pressure

of the foot by loosening the thumbscrew D (Fig. 79). Use a small size

stitch--set the feed so that the teeth are just above the needle plate.

Do not have the teeth too sharp, and if necessary, rub off the knife edge

with F emery-cloth. Make the foot to bear squarely on the needle plate,

and the feed square to the presser foot. Round off all sharp edges from

the under side of the foot, especially the back edge. Special feeders are

made for silk goods in machines used for factory work, which overcome the

difficulty of puckering.

By attention to the foregoing instructions, a machine should work easily,

especially if the fabric is slightly pulled from behind the pressure foot.

In C. B. machines, attention should also be given to the loop as it passes

over the bobbin case and off the stop pin, it being necessary sometimes

to round off the latter. If the tension spring screw projects too high or

is rough, it may occasionally catch the cotton.

The machine shown at Fig. 81 is of the "Rotary Hook"--zigzag type.

Its uses are similar to that of the oscillating shuttle type, but its

construction is rather more complicated.

[Illustration: Fig. 81. Rotary hook--Zigzag type]

[Illustration: Fig. 82. Rocking frame]

The machine may be said to consist chiefly of an upper and a lower shaft,

each having two cranks. In the vertical portion of the arm are two links

which connect the shafts, causing them to work in unison with each other.

The upper shaft gives motion by means of a cam and link to the needle bar

and take-up lever; while the lower shaft, by means of three gear wheels,

gives the rotary movement to the hook or shuttle, and by an eccentric

cam and segment lever the necessary motion is given to the feed or stitch

mechanism. Figure 82 shows the rocking frame into which the needle bar is

fitted at A and B, while, at C and D, it is recessed to receive the taper

ends of two screws, which pass through the face plate end of the machine

arm. These screws are held secure by lock nuts, so screwed in as to allow

the frame to rock freely. A ball-headed screw is fitted at E, to which

is fastened a connection rod extending to a switch lever situated about

the centre of the arm. This lever, by means of a cam movement, gives the

vibrating motion to the needle bar, which can be regulated according to

the relative position of the connection rod and lever. When the rod is at

the bottom of the lever, a wide throw is obtained. By raising the rod a

narrower throw is given, and if raised to the position shown in Fig. 81 no

vibration will be given to the needle bar. The needle bar can be raised or

lowered by loosening the screw that secures it to its link collar, which

will be better seen by removing the face plate. Most needle bars have two

marks upon them, and they should be set as follows: Remove the face plate,

and turn the hand wheel F (Fig. 81) toward you until the needle bar link

has reached its lowest point of travel.

Loosen the set screw of the needle bar collar, and set the needle bar so

that its highest mark will be just level with the bottom of the rocking

frame (Fig. 82). Then tighten the set screw, give the hand wheel a spin

round, and again examine the position of the mark when the needle bar

has reached its lowest point of travel, to make sure that no mistake has

been made. Of course, it is necessary when parts are badly worn to set

the needle bar a trifle lower, but this can be done after the foregoing

rule has been adopted and proved a failure. In case of any unnecessary

looseness in the middle bar or any of its connecting parts, they should

be taken out and new parts fitted. The position of the needle may be

altered to the right or left by loosening the screws G and H (Fig. 81),

and adjusting the connection rod. Care should be taken not to set the

connection rod too low down, or the needle may strike on the needle plate

and cause trouble.

[Illustration: Fig. 83. Section showing face plate removed from machine]

Fig. 83 shows the face plate removed from the machine arm, A being a

tension release lever. When the presser foot is lifted to its highest

position, the end of the lever goes between the tension disc, thus

releasing all tension, so that materials can be taken from the machine

without drawing slack cotton, or putting any unnecessary strain on the

needle. When the presser foot is lowered, this lever should withdraw

itself from the disc, thus allowing the proper tension to be put on the

cotton. In some machines the withdrawal of this lever depends on a stud

screw, fastened to the needle bar and projecting through the face plate.

In the downward course of the needle bar this stud screw touches a spring,

and causes the lever to trip backward. Should the spring become strained,

or the stud screw become raised up a little, the release lever may remain

between the disc and cause trouble. Sometimes it is necessary to bend the

lever forward or backward to ensure its proper action.

[Illustration: Fig. 84. Hook ring]

[Illustration: Fig. 85. Hook guide]

[Illustration: Fig. 86. Hook driver]

The hook or shuttle is rotary in motion. The hook (Fig. 84), is fitted

to a ring, which is fixed to the hook guide (Fig. 85) by means of three

small pins, and it is prevented from falling out by a steel cap secured

with two screws and springs. The hook is carried round by a driver (Fig.

86). Much depends on the hook, driver, and hook guide, so that a little

detailed information is necessary. The hook driver must be a perfect fit

in its bearings and free from sharp places where it comes in contact with

the hook. The body of this driver is generally hardened, but the prong J

(Fig. 86) is left soft so that it can be bent to meet requirements. When

a machine is stitching, the hook driver rotates, and the prong J draws a

given amount of slack cotton from the bobbin case. The farther this prong

stands out, the more slack cotton it draws off the bobbin. The prong may

be bent inward, as shown by the dotted lines, but care must be taken not

to drive it in so far as to allow the needle when descending, to strike

on it, or to deviate from its true vertical position. Points K and L fit

between the nose and neck of the hook, while M comes against the heel.

The hook is driven alternately by points K and M. When the hook is just

entering the loop formed by the needle, it (the hook) is being driven by

the driver wheel or M, and an opening is being made between point K and

the hook nose for the free passage of the cotton. When the loop is being

drawn off the hook by the take-up lever, the hook is driven by point K,

and an opening is made between M and the heel of the hook for the exit

of the cotton. There must always be sufficient clearance at points K, L,

and M for the cotton or thread being used. As the heel of the driver M

wears, the space at K will be reduced. Sometimes this can be remedied by

bending the driver in at M, by giving it a blow with a hammer, placing a

brass punch at M, but this should not be attempted if the driver is very

hard. There is a means of adjustment provided in the hook guide (Fig. 85).

This part is held in position by two set screws N and O. At the left of O

is a small adjusting screw P. Supposing there is not sufficient space at

point K (Fig. 86), for the cotton to pass, loosen the screw O (Fig. 85),

and slightly tighten the screw P. This will tilt the hook guide and give

more space. Should the screw P be turned in too far, the point L (Fig.

86), will be brought in contact with the narrow part of the hook near

the neck, and this will impede its freedom, so that if allowed to run at

much speed, the probable result will be the breaking of the hook off at

the neck. This should be noticed in fitting a new hook, as the adjusting

screw P (Fig. 85) will in all probability require loosening. The screws

at N and O, however, must be kept quite tight. At each side of N is a

small screw hole. The screws which fit here are for adjusting the hook

closer to or farther from the needle. As an example, supposing a very fine

needle has been used in the machine, and it is now required to take a very

coarse one on account of the thick material to be stitched, the hook in

all probability would strike the needle, indicating that the hook guide

requires moving back a little. To do this, loosen the two small adjusting

screws and tighten the set screw in N. Afterward try the set screw in

O to ascertain if it is secure. In this way, the hook is thrown farther

from the needle. Loosening the screw at N, and tightening the adjusting

screws, will bring the hook forward. If the hook stands too far from the

needle, it is likely to miss the loop. The hook nose must be well pointed

and perfectly smooth, roughness or sharpness removed from any part of the

hook over which the cotton passes during the formation of a stitch.

Hook rings are made in three sizes, numbers 1, 2, and 3. Number 1 is for

a new hook, numbers 2 and 3 are for fitting as the hook wears. No matter

what size of ring is used the hook must have perfect freedom. Sometimes

the three pins in the guide draw the ring, and cause the hook to bind. It

is best, therefore, to fix the ring to the guide, and then test the hook.

If it is at all tight, grind it on the rim by means of an emery wheel or

a grindstone. If neither is available, use number 1 or number 1-1/2 emery

cloth first, finishing with number 00 emery cloth. It is better to have

the hook a little loose, even sluggish, than too tight. The timing of the

hook will be dealt with later on.

[Illustration: Fig. 87. Bobbin case]

[Illustration: Fig. 88. Bobbin case in position]

[Illustration: Fig. 89. Bobbin in position in bobbin case--Method of

threading]

The bobbin case (Fig. 87), fixes to a stud in the centre of the hook. It

is held in position, that is, kept from revolving with the hook, by means

of a stop pin, Q, fitting between a holder. The tension is obtained by a

spring, R, which is regulated by turning a small screw, S, to the right

to tighten and to the left to loosen. Fig. 88 shows the bobbin case in

position, with the holder raised ready for taking it out of the machine.

Fig. 89 shows the bobbin in position in the bobbin case and method of

threading, and Fig. 91, the direction the cotton should draw off the

bobbin when it is in the machine. It will be noticed that the cotton

pulls in the opposite direction to which the hook travels, as shown by

an arrow in Fig. 88. The bobbin case holder (Fig. 91), should prevent the

bobbin case from revolving with the hook. As parts wear, the bobbin case

is liable to slip past the holder, causing the cotton to be stranded and

broken. When such is the case the holder should be bent as shown by (Fig.

92), but it must not fit so tightly against the bobbin case as to cause

the cotton to become trapped. The holder is held rigid by means of a catch

and spring T (Fig. 88). Should the catch or holder become worn, fit new

parts by driving out the pins U and V. Any sharpness or roughness on the

forked part of the holder should be removed. Should the stop pin Q (Fig.

87) become loose, it should be soldered and well cleaned with an emery

cloth. The centre tube of the bobbin case should also be kept quite firm.

Should it become loose, place it over some hard substance, rivet it until

tight, and thoroughly smooth with very fine emery cloth.

[Illustration: Fig. 90. Direction cotton should draw off]

[Illustration: Figs. 91 and 92. Bobbin case holders]

[Illustration: Fig. 93. Take-up spring]

The take-up spring (Fig. 93) is attached to the face plate, and is shown

in position in Fig. 83. Replace a new one as follows: First take out the

set screw W (Fig. 93), and remove the complete thread controller from the

face plate. Then take out the screw and withdraw the old spring. Place the

ring part of the new spring in the recess between plate Y and back plate

Z, and replace the screw X, being careful not to get the spring fastened

under the screw head. This done, fix the spring and other parts on the

face plate. A small barrel with a slot in it receives the coiled portion

of the spring. See that the part of the spring that is turned in enters

the slot in the barrel, then replace the screw W, but before tightening

this screw, see that the hooked part of the spring A´ rests on the

regulator B´, which determines the amount of action given to the take-up

spring. By raising it, less action is given. The amount of pressure on

the spring is regulated by adjusting the barrel in the face plate. Take

off the face plate, loosen the screw C (Fig. 83), fix a screw-driver in

the rear of the barrel (seen inside the face plate), turn it toward you

for more pressure, and backward for less and tighten the set screw C.

[Illustration: Figs. 94, 95, 96. Presser foot with details]

Presser feet are made solid for ordinary purposes, although alternating

feet can be fitted when desired. Figs. 94, 95, and 96 show a pressure

foot, collar, and spring. To fix this foot, remove the ordinary presser

foot, turn the foot bar round by loosening the set screw, so that the

groove made for the reception of the presser foot is directly behind

the needle. Put on the collar (Fig. 95), then turn the foot (Fig. 94),

and screw it in position. Next place the spring each side at the points

D´ (Fig. 94), press down the collar (Fig. 95), and secure it by its set

screw. The springs will act on each half of the foot, and keep them

firm, though the material be uneven. The foot is particularly useful

when overseaming a hem or the top band of a lady's boot, etc. To time the

hook and needle, raise the connection rod so as to produce no throw, and

tighten the screw as in Fig. 81. Then take off the needle plate and remove

the slide E´ (Fig. 81) under which will be seen a crank and screws.

Now turn the machine back as at Fig. 88, lift up the bobbin case holder by

pressing the catch T, and remove the bobbin case. Take off the hook guide

cap by removing the two screws. Turn the hand wheel F (Fig. 81), toward

you, until the needle bar has descended to its lowest point of travel,

and loosen the crank screw farthest from you. Having done this, continue

turning the hand wheel until the needle bar has risen. With the lowest

mark level with the rocking frame casting, at this point, examine the

hook, the point of which should be just up to the needle. If otherwise,

loosen the other screw in the crank under the plate E´ (Fig. 81). Be sure

the needle bar mark is level with the rocking frame, place the hook with

its point just up to the needle, and tighten the crank set screw, being

careful to have no end play to the short shaft. Again examine the needle

bar and hook and if in proper time finally secure crank set screws and

replace the fittings previously removed. Thread the machine as indicated

(Fig. 81). Set the needle as high in the bar as it will go, with the long

groove facing the operator, and thread the needle from the long groove

side. The stitch regulator will be found at F´ (Fig. 81). The raising of

it will shorten and the lowering of it will lengthen the stitch. The feed

should be set about one thirty-second of an inch above the needle plate

when at its highest point. To raise the feed, turn the machine back as in

Fig. 88. Near to the part G (Fig. 88) will be found a large set screw.

Loosen it and press the lever H (Fig. 88) upward raising the feed bar J

as high as required, and tighten the set screw at G firmly. To remove the

feed for cleaning and sharpening, take off the needle plate, under which

will be seen two feed set screws. By unscrewing these, the feed can be

lifted out.

One of the modern machines on the market is the Wheeler and Wilson, known

as the Number 61, which is of rotary hook principle. The hook forms part

of the under shaft, somewhat similar to that known as the D9 W and W. This

hook and shaft revolves in two long bearings, and is held in position by

a fluted wheel, which forms a collar at the right-hand end; thus when

set properly no end play is permitted. This is an advantage over the

boat-shaped shuttle machine. In the latter, the shuttle rocks about,

becomes worn on the surface, often blunt pointed by striking the needle.

As it wears, it becomes loose in the carrier, thus giving it freedom to

roll away from or toward the needle, as well as making its action with

relation to the needle very uncertain; and on account of the number of

little loosenesses in fittings that this uncontrolled shuttle produces,

missed stitches are frequent, and difficult to remedy, unless a number of

new fittings are obtained or old ones repaired.

If there is any alteration required in the time of the rotary hook

referred to, it can be made to the smallest fractional part of an inch

very quickly and easily, and the movement can be relied on. The shaft to

which it is secured is positive in its action (no variable motion), and

at every stitch will meet the needle at exactly the same spot. This is

an improvement over the boat-shaped shuttle, which has to have a certain

amount of play or slackness to allow the loop to extricate itself; and

this slackness increases as the machine is worked, so that the shuttle

action often becomes very erratic.

Sometimes a carrier becomes sprained at one end, thus allowing the shuttle

too much freedom. If at the heel end, the carrier should be removed and

placed in a vise (heel uppermost). The heel should be given a light blow

with a hammer, thus bending it into correct position, but it must never be

allowed to incline toward the shuttle; it should stand perfectly square,

and have the upper corners rounded off. If inclined toward the shuttle,

the loop may occasionally hang on the heel, and cause an irregular

tension.

In some machines the bobbin case holder (Fig. 97) rests on the casting

seen in Fig. 81. It is secured by a large set screw, D (Fig. 97). For

general use, this screw should be adjusted to allow number 40 cotton to

pass freely over the bobbin case. The holder should not be removed, except

when adjustment or repair is needed. The vertical portion is hinged to

the base, and is kept upright by a lock spring and stud. If the spring is

pressed from the stud, the vertical or ring part can be drawn back for

placing in or taking out the bobbin case. The face of this portion must

be perfectly square with the bottom of the base, otherwise it may cause

considerable trouble. A slight adjustment can be made by loosening the

two screws and moving the lock spring. A set square, E, should be used

for testing the accuracy of this part as shown (Fig. 98), F representing

the bobbin case holder.

[Illustration: Fig. 97. Bobbin case holder]

[Illustration: Fig. 98. Set square]

The thread controller is similar in design to several others, but its

movement is regulated by a small lever (Fig. 99) which receives its motion

from a link attached to the foot bar bracket set screw, and this may be

seen through a hole in the face plate. At G (Fig. 99), this lever engages

with a stop washer located behind the thread controller plate. The washer

is recessed to form a stop, at the same time to give sufficient clearance

for the action of the spring; thus as the foot bar rises and falls, so

does the thread controller spring. It is a common practice when cleaning a

machine to remove the face plate, thus detaching the link referred to, and

not connecting it again when replacing the face plate. From this, trouble

arises. The tension pulley should be placed on its stud, the large boss

being toward the face plate.

[Illustration: Fig. 99. Lever]

Thread a machine as follows: From the reel pin to nipper F (Fig. 81),

round tension pulley G as the arrow indicates, down and into thread

controller H up to take-up lever, threading over the roll and through the

slot from the top of lever, then down the thread guide J, into guide K,

and through the needle-eye from right to left.

In the ordinary boat-shaped shuttle, the looping up of the thread is not

difficult. The needle, as it descends, enters an opening or cavity in the

carrier, one side of which forms a support for the needle and guards it

from contact with the shuttle point. Now, it is important that there be

clearance for the needle. If the carrier stands so prominent as to spring

the needle out of its true vertical line it will carry it away from the

shuttle, and give the latter a chance to miss the loop.

[Illustration: Fig. 100 A, B, C, D. Carriers and drivers]

Then there are carriers and drivers of varying heights. Those of the

raised kind are preferable, if properly fitted. By "raised" is meant

that they are higher, so as to form a better guard for the needle, as

previously referred to (Fig. 100 A, in which E indicates the portion of

raised carrier, F the shuttle point, and G the needle). But sometimes

they are too high, and permit the needle-eye to be buried in the carrier,

thus preventing the proper formation of the loop. This can be so bad as

to cause very frequent missing; or it may be of such a slight character

as to cause a miss-stitch only now and then. Occasionally, a needle bar

has to be lowered, and that is sufficient to cause the same fault. The eye

of the needle should always be about one thirty-second of an inch above

the upper edge of the carrier, and the latter should be shaped so as to

allow that amount of clearance the whole of the time the needle is rising

to form the loop, until the shuttle point has well entered the same. Fig.

100 B shows how a carrier is hollowed to give the necessary clearance to

the needle eye.

[Illustration: Fig. 101. Sewing machine items]

When a machine is reasonably tight in all parts, gauges and setting marks

may be adhered to for the preliminary adjustments; and then if the machine

works erratically, other adjustments must be made. Where no marks or

gauges are furnished for the adjustment of the needle bar, it should be

so set as to allow the shuttle or hook to enter the bold part of the loop

formed from the needle. A good rule is to set the needle bar so that the

needle-eye is about 1/32 inch below the point of the shuttle M (Fig. 100

C) when the latter is up to the centre of the needle groove. But this may

have to be varied from 1/64-inch to 3/32-inch. In boat-shaped and similar

shuttle machines, a good rule is to set the needle so that the eye N will

pass just below the lower side of the shuttle O as the latter is passing

through the loop as in Fig. 100 D, P, indicating the level of the bed

plate.

II

MECHANICAL MOVEMENTS

What is meant by this term is that these devices are intended for the

transmission of motion. Motion in mechanics may be simple or compound.

Simple motions are those of straight translation, which if of indefinite

duration must be reciprocating, or what is called oscillating or helical.

Compound motions consist of combinations of any of the simple motions.

Perpetual motion is an incessant motion conceived to be attainable by a

machine supplying its own motive forces independently of any action from

without, or which has within itself the means, when once set in motion,

of continuing its motion perpetually, or until worn out, without any new

application of external force. The machine by means of which it has been

attempted, or supposed possible to produce such motion, is an invention

much sought after, but physically impossible.

[Illustration: Fig. 102. Coffee mill and details]

The illustrations herewith exhibit a number of devices of various kinds,

well known to the practical mechanician and professional engineer, and

usually called mechanical movements. It is estimated there are no less

than 1,500 of these movements doing service at the present day; but many

of them are, of course, quite complex, and difficult to master. In this

book, I show about one hundred of the simplest sort, or those in common

use. Their usefulness will at once be appreciated if we refer to Fig. 102,

which shows a machine for grinding or breaking up substances within its

capacity. It contains within itself the true principle of the little mill

used to grind coffee. The word "grind" in this connection is scarcely the

right one, as the mill rather "crushes" or breaks up, than grinds. You

will notice coffee, ready for use, is coarse and unlike flour in texture,

the latter being "ground" fine and smooth. In grinding, the abrading

surfaces are brought very much closer together than in the breaking or

crushing processes. In a coffee mill, the berries or grains drop into a

vacancy, left between the revolving cone and the walls of the mill. The

vacancy between the walls and the cone is a little less at the bottom

where the crushed coffee is discharged, and this enables the small and

large grounds to fall into the drawer. The detailed plan in illustration

(Fig. 102) shows a mill complete, as well as the various parts. It will

be noticed that the cone (Fig. 5), is corrugated or grooved as shown (Fig.

4). Figs. 6 and 7 show sections of lining at B and C (Fig. 3). A shows the

hopper into which the coffee berries are placed before grinding. Figure 9

shows the crank detached, and Figs. 8 and 10 show the remaining parts of

the machine, while Figs. 1 and 2 show the handle and drawer. The latter

is to receive the ground or crushed coffee after it has gone through

the mill. Further description is unnecessary if we take for example the

movement represented at Fig. 150, which is a sort of ball-bearing motion,

only instead of small balls wheels are used. Besides being made use of in

bicycles in small balls, it is used as depicted for "hanging" grindstones,

and for many other similar purposes.

The device also shown at Fig. 139, is one in common use. It is a

modification of the sprocket wheel on the bicycle. Many of the devices

shown herewith are rarely noticed because of our familiarity with them.

The action of pumps, the working of pistons, the changing of motion, and

many other things are shown and explained in the little illustrations

given in these descriptions, which do not pretend to be exhaustive, or

even full.

Fig. 103. In this the lower pulley is movable. One end of the rope

being fixed, the other has to move twice as fast as the weight, and a

corresponding gain of power is consequently effected.

Fig. 104 is a simple pulley used for lifting weights. In this the power

must be equal to the weight to obtain equilibrium.

Fig. 105. Blocks and tackle. The power obtained by this contrivance is

calculated as follows: Divide the weight by double the number of pulleys

in the lower block; the quotient is the power required to balance the

weight.

Fig. 106 represents what are known as "White's pulleys", which can be made

with separate loose pulley; or a series of grooves can be cut in a solid

block, the diameters being made in proportion to the speed of the rope;

that is, 1, 3, and 5 for one block, and 2, 4, and 6 for the other. Power

as 1 to 7.

[Illustration: Figs. 103, 104, 105, 106, 107. Various phases of block and

tackle]

Figs. 107-108 are what are known as Spanish bartons.

Fig. 108 is a combination of two fixed and one movable pulley.

Figs. 111-113 are different arrangements of pulleys. The following rule

applies to these: In a system of pulleys where each is embraced by a cord

attached to one end of a fixed point, and at the other to the centre

of the movable pulley, the effect of the whole will be the number 2

multiplied by itself as many times as there are movable pulleys in the

system.

[Illustration: Figs. 108, 109, 110, 111, 112. Other combinations of blocks

and pulleys]

Fig. 114. Endless chain for maintaining power on going barrel, to keep

a clock going while winding, as during that operation the action of the

weight or mainspring is taken off the barrel. The wheel to the right is

the going wheel, and that to the left the striking wheel. P is a pulley

fixed to the great wheel of the going part, and roughened to prevent

a rope or chain hung over it from slipping. A similar pulley rides on

another arbour, _p_, which may be the arbour of the great wheel of the

striking part, attached by a ratchet and click to that wheel, or to the

clock frame if there is no striking part. The weights are hung as may

be seen, the small one being only large enough to keep the rope or chain

on the pulleys. If the part _b_ of the rope or chain is pulled down, the

ratchet-pulley runs under the click, and the great weight is pulled up by

_c_, without taking its pressure off the going wheel at all.

Fig. 115. Triangular eccentric, giving an intermittent reciprocating

rectilinear motion, often used for the valve motion of steam-engines.

Fig. 116. Ordinary crank-motion.

[Illustration: Figs. 113, 114, 115. Blocks and rocker]

Fig. 117. In this, rotary motion is imparted to the wheel by the rotation

of the screw, or rectilinear motion of the slide by the rotation of the

wheel. Used in screw cutting and slide lathes.

[Illustration: Figs. 116, 117. Crank and rotary motion]

Fig. 118. Uniform circular into uniform rectilinear motion; used in

spooling frames for leading or guiding the thread on to the spools. The

roller is divided into two parts, each having a fine screw-thread cut upon

it, one a right and the other a left-handed screw. The spindle, parallel

with the roller, has arms which carry two half nuts, fitting to the screw,

one over the other under the roller. When one half nut is in, the other

is out of gear. By pressing the lever to the right or left the rod is made

to traverse in either direction.

Fig. 119. A system of crossed levers, termed "lazy tongs." A short,

alternating rectilinear motion of rod at the right will give a similar,

but much greater motion to the rod at the left. It is frequently used

in children's toys. It has been applied to machines for raising sunken

vessels; also applied to ship pumps three quarters of a century ago.

[Illustration: Figs. 118, 119. Rectilinear motion]

Fig. 120. Centrifugal governor for steam engines. The central spindle and

attached arms and balls are driven from the engine by the bevel gears at

the top, and the balls fly out from the centre by centrifugal force. If

the speed of the engine increases, the balls fly out from the centre,

raise the slide at the bottom, and thereby reduce the opening of the

regulating valve, which is connected with the slide. A diminution of speed

produces an opposite effect.

Fig. 121. Water-wheel governor acting on the same principle as Fig. 120,

but by different means. The governor is driven by the top horizontal

shaft and bevel gears, and the lower gears control the rise and fall of

the shuttle or gate over or through which the water flows to the wheel.

The action is as follows: The two bevel gears on the lower part of the

centre spindle, which are furnished with studs, are fitted loosely to the

spindle, and remain at rest so long as the governor has a proper velocity;

but immediately the velocity increases, the balls flying farther out,

draw up the pin, which is attached to a loose sleeve which slides up and

down the spindle, and this pin, coming in contact with the stud on the

upper bevel gear, causes that gear to rotate with the spindle, and to give

motion to the lower horizontal shaft in such a direction as to make it

raise the shuttle or gate, and so reduce the quantity of water passing to

the wheel. On the contrary, if the speed of the governor decreases below

that required, the pin falls and gives motion to the lower bevel gear,

which drives the horizontal shaft in the opposite direction, and produces

a contrary effect.

Fig. 122. Another arrangement for a water-wheel governor. In this the

governor controls the shuttle or gate by means of the cranked lever, which

acts on the strap or belt in the following manner: The belt runs on one of

three pulleys, the middle one of which is loose on the governor spindle,

and the upper and lower ones fast. When the governor is running at the

proper speed the belt is on the loose pulley, as shown; but when the speed

increases, the belt is thrown on the lower pulley, and thereby caused to

act upon suitable gearing for raising the gate or shuttle and decreasing

the supply of water. A reduction of the speed of the governor brings the

belt on the upper pulley, which acts upon the gearing for producing an

opposite effect on the shuttle or gate.

Fig. 123. Another form of steam-engine governor. Instead of the arms being

connected with a slide working on a spindle, they cross each other, are

elongated upward beyond the top, and connected with the valve-rod by two

short links.

Figs. 124, 125. Diagonal catch and hand-gear used in large blowing and

pumping engines. In Fig. 124 the lower steam valve and upper eduction

valves are open, while the upper steam valve and lower eduction valve

are shut; consequently the piston is ascending. In the ascent of the

piston rod the lower handle will be struck by the projecting tappet, and

being raised will become engaged by the catch, so as to shut the upper

eduction and lower steam valves; at the same time the upper handle will

be disengaged from the catch, the back weight will pull the handle up

and open the upper steam and lower eduction valves, when the piston will

consequently descend. Fig. 125 represents the position of the catches and

handles when the piston is at the top of the cylinder. In going down, the

tappet of the piston rod strikes the upper handle, and throws the catches

and handles to the position shown in Fig. 124.

[Illustration: Figs. 120, 121, 122, 123. Governors for steam-engines]

Fig. 126. A mode of driving a pair of feed rolls, the opposite surface of

which require to move in the same direction. The two wheels are precisely

similar, and both gear into the endless screw, which is arranged between

them. The teeth of one wheel only are visible, those of the other being

on the back or side which is concealed from view.

[Illustration: Figs. 124, 125, 126. Valve Regulation and Feed Rolls]

Fig. 127. Link-motion valve gear of a locomotive; two eccentrics are used

for one valve, one for the forward and the other for the backward movement

of the engine. The extremities of the eccentric rods are jointed to a

curved slotted bar, or, as it is termed, a link, which can be raised or

lowered by an arrangement of levers terminating in a handle, as shown.

In the slot of the link is a slide and pin connected with an arrangement

of levers terminating in the valve stem. The link, in moving with the

action of the eccentrics, carries with it the slide, and thence motion

is communicated to the valve. Suppose the link raised so that the slide

is in the middle, then the link will oscillate on the pin of the slide,

and consequently the valve will be at rest. If the link is moved so that

the slide is at one of the extremities, the whole throw of the eccentric

connected with that extremity will be given to it, the valve and steam

ports will be opened to the full, and it will only be toward the end of

the stroke that they will be totally shut; consequently the steam will

have been admitted to the cylinder during almost the entire length of each

stroke. But if the slide is between the middle and the extremity of the

slot, as shown in the figure, it receives only a part of the throw of the

eccentric and the steam ports will only be partially opened, and quickly

closed again, so that the admission of steam ceases some time before the

termination of the stroke, and the steam is worked expansively. The nearer

the slide is to the middle of the slot the greater will be the expansion,

and vice versa.

[Illustration: Figs. 127, 128. Link and other motions]

Fig. 128 represents a mode of obtaining motion from rolling contact. The

teeth are for making the motion continuous, or it would cease at the point

of contact shown in the figure. The fork catch is to guide the teeth into

proper contact.

Fig. 129. What is called the Geneva-stop, used in Swiss watches to limit

the number of revolutions in winding-up; the convex curved part of the

wheel serving as the stop.

Fig. 130. A continuous rotary motion of the large wheel gives an

intermittent rotary motion to the pinion-shaft. The part of the pinion

shown next the wheel is cut of the same curve as the plain portion of the

circumference of the wheel, and therefore serves as a lock while the wheel

makes a part of a revolution, and until the pin upon the wheel strikes

the guide-piece upon the pinion, when the pinion-shaft commences another

revolution.

[Illustration: Figs. 129, 130. Stop and rotary motions]

Fig. 131. The two crank-shafts are parallel in direction, but not in line

with each other. The revolution of either will communicate motion to the

other with a varying velocity, for the wrist of one crank working in the

slot of the other is continually changing its distance from the shaft of

the latter.

[Illustration: Figs. 131, 132, 133. Irregular Motions]

Figs. 132 and 133. These are parts of the same movement, which has been

used for giving the roller motion in wool-combing machines. The roller

to which the wheel F, (Fig. 132) is secured, is required to make 1/3

revolution backward, then 2/3 revolution forward, when it must stop until

another length of combed fibre is ready for delivery. This is accomplished

by the grooved heart-cam C, D, B, e, (Fig. 133) the stud working in the

said groove; from C to D it moves the roller backward, and from D to e

it moves it forward, the motion being transmitted through the catch G, to

the notch wheel F, on the roller-shaft H. When the stud A arrives at the

point e in the cam, a projection at the back of the wheel, which carries

the cam, strikes the projecting piece on the catch G, and raises it out

of the notch in the wheel F, so that while the stud is travelling in the

cam from e to C, the catch is passing over the plain surface between the

two notches in the wheel F, without imparting any motion; but when stud

A arrives at the part C, the catch has dropped in another notch and is

again ready to move wheel F and roller as required.

Fig. 134. An arrangement for obtaining variable circular motion. The

sectors are arranged on different planes, and the relative velocity

changes according to the respective diameters of the sectors.

Fig. 135. Intermittent circular motion of the ratchet-wheel from vibratory

motion of the arm carrying a pawl.

[Illustration: Figs. 135, 134, 137, 136. Movements of various kinds]

Fig. 136. This represents an expanding pulley. On turning pinion _d_ to

the right or left, a similar motion is imparted to wheel _c_, by means

of curved slots cut therein, which thrust the studs fastened to arms of

pulley outward or inward, thus augmenting or diminishing the size of the

pulley.

Fig. 137 represents a chain and chain pulley. The links being in different

planes, spaces are left between them for the teeth of the pulley to enter.

Fig. 138. Another kind of chain and pulley.

Fig. 139. Another variety.

Fig. 140 shows two different kinds of stops for a lantern-wheel.

[Illustration: Figs. 140, 138, 139. Chain pulleys and lantern-wheel]

Fig. 141. Intermittent circular motion is imparted to the toothed wheel

by vibrating the arm B. When the arm B is lifted, the pawl C is raised

from between the teeth of the wheel, and travelling backward over the

circumference again drops between two teeth on lowering the arm, and draws

with it the wheel.

Fig. 142. The oscillating of the tappet-arm produces an intermittent

rotary motion of the ratchet-wheel. The small spring at the bottom of the

tappet-arm keeps the tappet in the position shown in the drawing, as the

arm rises, yet allows it to pass the teeth on the return motion.

Fig. 143. A nearly continuous circular motion is imparted to the

ratchet-wheel on vibrating the lever _a_ to which the two pawls _b_ and

_c_ are attached.

[Illustration: Figs. 141, 142, 143. Intermittent circular motion]

Fig. 144. An arrangement of stops for a spur-gear.

Fig. 145. A reciprocating circular motion of the top arm makes

its attached pawl produce an intermittent circular motion of the

crown-ratchet, or ray-wheel.

[Illustration: Figs. 144, 145. Intermittent circular motion]

Fig. 146 represents varieties of stops for ratchet-wheel.

Fig. 147. Intermittent circular motion is imparted to the wheel A by the

continuous circular motion of the smaller wheel with one tooth.

[Illustration: Figs. 146, 147. Ratchet motion]

Fig. 148. A dynamometer, or instrument used for ascertaining the amount

of useful effect given out by any motive power. It is used as follows: A

is a smoothly turned pulley, secured on a shaft as near as possible to

the motive power. Two blocks of wood are fitted to this pulley, or one

block of wood and a series of straps fastened to a band or chain, as in

the drawing, instead of a common block. The blocks, or block and straps,

are so arranged that they may be made to bite or press upon the pulley

by means of the screws and nuts on the top of the lever D. To estimate

the amount of power transmitted through the shaft, it is only necessary

to ascertain the amount of friction of the drum A when it is in motion,

and the number of revolutions made. At the end of the lever D is hung a

scale B, in which weights are placed. The two stops C C are to maintain

the lever as nearly as possible in a horizontal position. Now, suppose

the shaft to be in motion, the screws are to be tightened and weights

added in B, until the lever takes the position shown in the drawing, at

the required number of revolutions. Therefore the useful effect would be

equal to the product of the weights, multiplied by the velocity at which

the point or suspension of the weights would revolve if the lever were

attached to the shaft.

[Illustration: Figs. 148, 149. Dynamometer--Pantagraph]

Fig. 149 represents a pantagraph for copying, enlarging and reducing

plans. One arm is attached to and turns on the fixed point C. B is an

ivory tracing point, and A the pencil. Arranged as shown, if we trace the

lines of a plan with the point B, the pencil will produce it double the

size. By shifting the slide attached to the fixed point C and the slide

carrying the pencil along their respective arms, the proportions to which

the plan is traced will be varied.

Fig. 150. Anti-friction bearing. Instead of a shaft revolving in an

ordinary bearing, it is sometimes supported on the circumference of

wheels. The friction is thus reduced to the least amount.

Fig. 151. Releasing hook used in pile-driving machines. When the weight

W is sufficiently raised, the upper ends of the hooks A, by which it is

suspended, are pressed inward by the side of the slot B, in the top of the

frame; the weight is thus suddenly released, and falls with accumulating

force on to the pile-head.

Fig. 152. A and B are two rollers which require to be equally moved to

and fro in the slot C. This is accomplished by moving the piece D, with

oblique slotted arms, up and down.

[Illustration: Figs. 150, 151, 152. Anti-friction--Drop hook--Regular

motion]

Fig. 153. Centrifugal check-hooks, for preventing accidents in case of

the breakage of machinery which raises and lowers workmen, or ores, in

mines. A is a framework fixed to the side of the shaft of the mine, and

having fixed studs D, attached. The drum on which the rope is wound is

provided with a flange B, to which the check-hooks are attached. If the

drum acquires a dangerously rapid motion, the hooks fly out by centrifugal

force, and one or other, or all of them, catch hold of the studs D, arrest

the drum, and stop the descent of whatever is attached to the rope. The

drum ought besides this, to have a spring applied to it, otherwise the

jerk arising from the sudden stoppage of the rope might produce a worse

effect than its rapid motion.

Fig. 154. A sprocket-wheel to drive or to be driven by a chain.

Fig. 155. A combination movement, in which the weight W moves with a

reciprocating movement, the down-stroke being shorter than the up-stroke.

B is a revolving disc, carrying a drum which winds around itself the cord

D. An arm C is jointed to the disc and to the upper arm A, so that when

the disc revolves, the arm A moves up and down, vibrating on the point G.

This arm carries with it the pulley E. Suppose we detach the cord from the

drum, tie it to the fixed point, and then move the arm A up and down. The

weight W will move the same distance, and in addition the movement given

it by the cord, that is to say, the movement will be doubled. Now, let us

attach the cord to the drum, and revolve the disc B, and the weight will

move vertically with the reciprocating motion, in which the down-stroke

will be shorter than the up-stroke, because the drum is continually taking

up the cord.

[Illustration: Figs. 153, 154, 155. Hooks--Sprocket--Combination movement]

Figs. 156, 157. The first of these figures is an end view, and the second

is a side view of an arrangement or mechanism for obtaining a series

of changes in velocity and direction. D is a screw on which is placed

eccentrically the cone B, and C is a friction roller, which is pressed

against the cone by a spring or weight. Continuous rotary motion, at

a uniform velocity of the screw D carrying the eccentric cone, gives a

series of changes of velocity and direction to the roller C. It will be

understood that during every revolution of the cone the roller would press

against a different part of the cone, and that it would describe thereon

a spiral motion, the movement in one direction being shorter than that in

the other.

[Illustration: Figs. 156, 157. Change of speed]

Fig. 158. An engine governor. The rise and fall of the balls K are guided

by the parabolic curved arms B, on which the anti-friction wheels L run.

The rods F, connecting the wheel L with the sleeve, move it up and down

the spindle C D.

Fig. 159. Toe and lifter for working poppet-valves in steam engines.

The curved toe on the rock-shaft operates on the lifter attached to the

lifting rod to raise the valve.

Fig. 160. Mercurial compensation pendulum. A glass jar of mercury is

used for the bob or weight. As the pendulum-rod is expanded lengthwise by

increased temperature, the expansion of mercury in the jar carries it to

a greater height therein, and so raises its centre of gravity relatively

to the rod sufficiently to compensate for downward expansion of the rod.

As rod is contracted by a reduction of temperature, contraction of mercury

lowers it relatively to rod. In this way the centre of oscillation is

always kept in the same place, and the effective length of pendulum always

the same.

[Illustration: Figs. 158, 159, 160. Governor, lifter, and pendulum]

Fig. 161. Compound bar compensation pendulum. C is a compound bar of brass

and iron, or steel brazed together with brass downward. As brass expands

more than iron, the bar will bend upward as it gets warmer, and will

carry the weights W, W, up with it, raising the centre of the aggregate

weight M, to raise the centre of oscillation as much as elongation of the

pendulum-rod would let it down.

Fig. 162. Watch regulator. The balance-spring is attached at its outer

end to a fixed stud R, and at its inner end to staff of balance. A neutral

point is formed in the spring at P, by inserting it between two curb-pins

in the lever, which is fitted to turn on a fixed ring concentric with

staff of balance, and the spring only vibrates between this neutral point

and staff of balance. By moving lever to the right, the curb-pins are made

faster, and by moving it to the left, an opposite effect is produced.

[Illustration: Figs. 161, 162. Compound bar--Hair spring]

Fig. 163. Compensation balance. _t_, _a_, _t´_ is the main bar of

balance, with timing screws for regulation at the ends. _t_ and _t´_ are

two compound bars, of which the outside is brass and the inside steel,

carrying weights _b_, _b´_. As heat increases, these bars are bent

inward, diminishing the inertia of the balance. As the heat diminishes,

an opposite effect is produced. This balance compensates both for its own

expansion and contraction, and that of the balance-spring.

Fig. 164. Parallel ruler, consisting of a simple straight ruler B, with

an attached axle C, and a pair of wheels _A A_. The wheels, which protrude

but slightly through the under side of the ruler, have their edges nicked

to take hold of the paper and keep the ruler always parallel with any

lines drawn upon it.

[Illustration: Figs. 163, 164. Balance--Ruler]

Fig. 165. Compound parallel ruler, composed of two simple rulers A, A,

connected by two crossed arms pivoted together at the middle of their

length, each pivoted at one end to one of the rulers, and connected with

the other one by a slot and sliding pin, as shown at B. In this the ends

as well as the edges are kept parallel. The principle of construction of

the several rulers represented is taken advantage of in the formation of

some parts of machinery.

Fig. 166. A simple means of guiding or obtaining a parallel motion of

the piston rod of an engine. The slide _a_ moves in and is guided by the

vertical slot in the frame, which has been planed to a true surface.

[Illustration: Figs. 165, 166. Ruler--Parallel motion]

Fig. 167. Parallel motion for direct-action engines. In this, the end of

the bar B C is connected with the piston-rod, and the end B slides in a

fixed slot D. The radius bar F A is connected at F with a fixed pivot,

and at A midway between the ends of B C.

[Illustration: Figs. 167, 168, 169. Parallel motion methods]

Fig. 168. Oscillating engine. The cylinder has trunnions at the middle

of its length, working in fixed bearings, and the piston rod is connected

directly with the crank, and no guides are used.

Fig. 169. Inverted oscillating or pendulum engine. The cylinder has

trunnions at its upper end, and swings like a pendulum. The crank shaft

is below, and the piston rod connected directly with crank.

Fig. 170. Section of disc-engine. Disc-piston, seen edgewise, has a motion

substantially like a coin when it first falls after being spun in the

air. The cylinder heads are cones. The piston rod is made with a ball

to which the disc is attached, said ball working in concentric seats in

cylinder-heads, and the left-hand end is attached to the crank arm or

fly-wheel on end of shaft at left. Steam is admitted alternately on either

side of piston.

Fig. 171. The gyroscope, or rotascope, an instrument illustrating the

tendency of rotating bodies to preserve their plane of rotation. The

spindle of the metallic disc C is fitted to return easily in bearings in

the ring A. If the disc is set in rapid rotary motion on its axis, and the

pintle F at one side of the ring A is placed on the bearing in the top of

the pillar G, the disc and ring seem indifferent to gravity, and instead

of dropping begin to revolve about the vertical axis.

Fig. 172. Bohnenberger's machine, illustrating the same tendency of

rotating bodies. This consists of 3 rings, _A_, _A´_, _A2_, placed one

within the other, and connected by pivots at right angles to each other.

The smallest ring, _A2_, contains the bearings for the axis of a heavy

ball B. The ball being set in rapid rotation, its axis will continue

in the same direction, no matter how the position of the rings may be

altered; and the ring A2, which supports it, will resist a considerable

pressure tending to displace it.

[Illustration: Figs. 170, 171, 172. Disc-engine and gyroscopes]

Fig. 173. What is called the gyroscope governor, for steam-engines,

introduced by Alban Anderson in 1858. A is a heavy wheel, the axle _B B´_

of which is made in two pieces connected together by a universal joint.

The wheel A is on one piece B, and a pinion I on the other piece _B´_. The

piece B is connected at its middle by a hinge-joint with the revolving

frame _H_, so that variations in the inclination of the wheel A will

cause the outer end of the piece _B_ to rise and fall. The frame _H_ is

driven by bevel gearing from the engine, and by that means the pinion 1

is carried round the stationary toothed circle _G_, and the wheel _A_ is

thus made to receive a rapid rotary motion on its axis. When the frame

H and wheel A are in motion, the tendency of the wheel A is to assume a

vertical position, but this tendency is opposed by a spring L. The greater

velocity of the governor, the stronger the tendency, above mentioned,

and the more it overcomes the force of the spring, and the reverse. The

piece B is connected with the valve rods by rods C, D, and the spring L

is connected with the said rods by levers N and rod P.

[Illustration: Figs. 173, 174, 175. Governor--Reverse motions]

Fig. 174. Pair of edge runners or chasers for crushing or grinding. The

axles are connected with vertical shaft, and the wheel or chasers run in

an annular pan or trough.

Fig. 175. Rotary motion of shaft from treadle by means of an endless band

running from a roller on the treadle to an eccentric on the shaft.

Fig. 176. Tread-wheel horse-power turned by the weight of an animal

attempting to walk up one side of its interior; has been used for driving

the paddle-wheels of ferry-boats and many other purposes. The turn-spit

dog used also to be employed in such a wheel in ancient times for turning

meat while roasting on a spit.

Fig. 177. The treadmill, employed in jails in some countries for

exercising criminals condemned to labour, and employed in grinding grain;

turns by weight of person stepping on tread-boards on periphery. This

is supposed to be a Chinese invention, and it is still used in China for

raising water for irrigation.

[Illustration: Figs. 176, 177, 178. By different sources of power]

Fig. 178. A. B. Wilson's four-motion feed, used in Wheeler and Wilson's,

Sloat's, and other sewing machines. The bar A is forked, and has a second

bar B, carrying the spur or feeder, pivoted in the said fork. The bar B

is lifted by a radial projection on the cam C, at the same time the two

bars are carried forward. A spring produces the return stroke, and the

bar B drops of its own gravity.

Fig. 179. Mechanical means of describing parabolas, the base, altitude,

focus, and directrix being given. Lay straight edge with near side

coinciding with directrix, and square with stock against the same, so that

the blade is parallel with the axis, and proceed with pencil in bight of

thread, as in the preceding.

[Illustration: Figs. 179, 180. To describe conic sections]

Fig. 180. Mechanical means of describing hyperbolas, their foci and

vertices being given. Suppose the curves two opposite hyperbolas, the

points in vertical dotted centre line their foci. One end of thread being

looped on pin inserted at the other focus, and other end held to other

end of rule, with just enough slack between to permit height to reach

vertex when rule coincides with centre line. A pencil held in bight, and

kept close to the rule, while latter is moved from centre line, describes

one-half of parabola; the rule is then reversed for the other half.

Fig. 181. Cyclograph for describing circular arcs in drawings where the

centre is inaccessible. This is composed of three straight rules. The

cord and versed sine being laid down, draw straight, sloping line from

ends of former to top of latter; and to these lines lay two of the rules

crossing at the apex. Fasten these rules together, and another rule across

them to serve as a brace, and insert a pin or point at each end of chord

to guide the apparatus, which, on being moved against these points, will

describe the arc by means of pencil in the angle of the crossing edges of

the sloping rules.

Fig. 182. Proportional compasses used in copying drawings on a given

larger or smaller scale. The pivot of compasses is secured in a slide

which is adjustable in the longitudinal slots of legs, and capable

of being secured by a set screw; the dimensions are taken between one

pair of points and transferred with the other pair, and thus enlarged

or diminished in proportion to the relative distances of the points

from the pivot. A scale is provided on one or both legs to indicate the

proportions.

Fig. 183. One of the many forms of rotary engine. A is a cylinder having

the shaft B pass centrally through it. The piston C is simply an eccentric

fast on the shaft, and working in contact with the cylinder at one point.

The induction and eduction of steam take place as indicated by arrows, and

the pressure of the steam on one side of the piston produces its rotation

and that of the shaft. The sliding abutment D, between the induction and

eduction ports, moves out of the way of the piston to let it pass.

[Illustration: Figs. 181, 182, 183. For drawing curves. Rotary engine]

Fig. 184. Another form of rotary engine, in which there are two stationary

abutments D, D, within the cylinder; and the two pistons A, A, in order to

enable them to pass the abutments, are made to slide radially in grooves

in the hub C of the main shaft B. The steam acts on both pistons at once,

to produce the rotation of the hub and shaft. The induction and eduction

are indicated by arrows.

Fig. 185. Jonval turbine. The shutes are arranged on the outside of a

drum, radial to a common centre, and stationary within the trunk or casing

_b_. The wheel _c_ is made in nearly the same way; the buckets exceed in

number those of the shutes, and are set at a slight tangent instead of

radially, and the curve generally used is that of the cycloid or parabola.

Fig. 186. A method of obtaining a reciprocating motion from a continuous

fall of water, by means of a valve in the bottom of the bucket which opens

by striking the ground, and thereby emptying the bucket, which is caused

to rise again by the action of a counterweight on the other side of the

pulley over which it is suspended.

[Illustration: Figs. 184, 185, 186. Different forms of water movements]

Fig. 187. Overshot water-wheel.

Fig. 188. Undershot water-wheel.

Fig. 189. Breast-wheel. This holds intermediate place between overshot

and undershot wheels; has float-boards like the former, but the cavities

between are converted into buckets by moving in a channel adapted to

circumference and width, into which water enters nearly at the level of

axle.

Fig. 190. Horizontal overshot water-wheel.

[Illustration: Figs. 187, 188, 189, 190. Water-wheels]

Fig. 191. A plan view of the Fourneyron turbine water-wheel. In the centre

are a number of fixed curved chutes, or guides, A, which direct the water

against the buckets of the outer wheel B, which revolves, and the water

discharges at the circumference.

Fig. 192. Warren's central discharge turbine, plan view. The guides _A_

are outside, and the wheel _B_ revolves within them, discharging the water

at the centre.

Fig. 193. Volate wheel, having radial vanes _A_, against which the water

impinges and carries the wheel around. The scroll or volute casing _B_

confines the water in such a manner that it acts against the vanes all

around the wheel. By the addition of the inclined buckets _c_, _c_, at

the bottom, the water is made to act with additional force as it escapes

through the openings of said buckets.

[Illustration: Figs. 191, 192, 193. Central discharge and turbine wheels]

Fig. 194. Barker, or reaction mill. Rotary motion of central hollow shaft

is obtained by the reaction of the water escaping at the ends of its arms,

the rotation being in a direction the reverse of the escape.

Fig. 195 represents a trough divided transversely into equal parts, and

supported on an axis by a frame beneath. The fall of water filling one

side of the division, the trough is vibrated on its axis, and at the same

time that it delivers the water the opposite side is brought under the

stream and filled, which in like manner produces the vibration of the

trough back again. This has been used as a water-meter.

Fig. 196. Persian wheel, used in Eastern countries for irrigation. It

has a hollow shaft and curved floats, at the extremities of which are

suspended buckets or tubs. The wheel is partly immersed in a stream acting

on the convex surface of its floats; and as it is thus caused to revolve,

a quantity of water will be elevated by each float at each revolution,

and conducted to the hollow shaft at the same time that one of the buckets

carries it full of water to a higher level, where it is emptied by coming

in contact with a stationary pin placed in a convenient position for

tilting it.

[Illustration: Figs. 194, 195, 196. Water motors]

Fig. 197. Machine of ancient origin, still employed on the river Eisach,

in the Tyrol, for raising water. A current keeping the wheel in motion,

the pots on its periphery are successively immersed, filled, and emptied

into a trough above the stream.

Fig. 198. Application of Archimedes screw for raising water, the supply

stream being the motive power. The oblique shaft of the wheel has

extending through it a spiral passage, the lower end of which is immersed

in water, and the stream acting upon the wheel at its lower end produces

its revolution by which the water is conveyed upward continuously through

the spiral passage and discharged at the top.

Fig. 199. Common lift pump. In the upper-stroke of piston or bucket the

lower valve opens and the valve in piston shuts; air is exhausted out

of suction pipe, and water rushes up to fill the vacuum. In down stroke

lower valve is shut and valve in piston opens, and the water simply passes

through the piston. The water above piston is lifted up, and runs over

out of spout at each up stroke. This pump cannot raise water over thirty

feet high.

[Illustration: Figs. 197, 198, 199. Water-wheels and pumps]

Fig. 200. Ordinary force pump, with two valves. The cylinder is above

water, and is fitted with solid piston; one valve closes outlet pipe, and

other closes suction pipe. When piston is rising suction-valve is open,

and water rushes into cylinder, outlet valve being closed. On descent of

piston suction valve closes, and water is forced up through outlet valve

to any distance or elevation.

Fig. 201. Double-acting pump. Cylinder closed at each end, and piston-rod

passes through stuffing-box on one end, and the cylinder has four openings

covered by valves, two for admitting water and like number for discharge.

A is suction pipe, and B discharge pipe. When piston moves down, water

rushes in at suction valve 1, on upper end of cylinder, and that below

piston is forced through valve 3 and discharge pipe B; on the piston

ascending again, water is forced through discharge valve 4, on upper end

of cylinder, and water enters lower suction valve 2.

[Illustration: Figs. 200, 201, 202. Pumps and windmill]

Fig. 202. Common windmill, illustrating the production of circular motion

by the direct action of the wind upon the oblique sails.

Fig. 203. Ordinary steering apparatus. Plan view. On the shaft of the hand

wheel, there is a barrel on which is wound a rope, which passes round the

guide-pulleys, and has its opposite ends attached to the tiller, or lever,

on top of the rudder; by turning the wheel, one end of the rope is wound

on and the other left off, and the tiller is moved in one or the other

direction, according to the direction in which the wheel is turned.

Fig. 204. Capstan. The cable or rope wound on the barrel of the capstan

is hauled in by turning the capstan on its axis by means of handspikes

or bars inserted into holes in the head. The capstan is prevented from

turning back by a pawl attached to its lower part and working in a

circular ratchet on the base.

[Illustration: Fig. 203. Cable]

[Illustration: Fig. 204. Capstan]

Fig. 205. Lewis bolt for lifting stone in building. It is composed of a

central taper-pin or wedge, with two wedge-like packing pieces arranged

one on each side of it. The three pieces are inserted together in a hole

drilled into the stone, and when the central wedge is hoisted upon it, it

wedges the packing pieces out so tightly against the sides of the hole as

to enable the stone to be lifted.

[Illustration: Figs. 205, 206. Lewis bolts, for lifting stones]

Fig. 206. Tongs for lifting stones. The pull on the shackle which connects

the two links causes the latter so to act on the upper arms of the tongs

as to make their points press themselves against or into the stone. The

greater the weight, the harder the tongs bite.

III

THE WEATHER AND INDOOR WORK

The measure of rainfall varies considerably within comparatively small

areas, and this renders it no easy matter to get correct figures, so

that the nearest records are those taken from a number of gauges within

a limited district, and generalized. The more this is done, the less will

be the inaccuracy in referring to the rainfall of any particular district

or country.

If numerous rain-gauges were established throughout the country, and all

their records sent to one central station, what valuable information might

be collected for a particular district or country in the course of years.

Means might be found for using the superabundant water, which falls in

one part over another part, where the rainfall is less. Information such

as this might be of special value in the West and South. It is collected

now to a certain extent; but not done so generally as it ought to be.

[Illustration: Fig. 207. Rain-gauge]

[Illustration: Fig. 208. A made rain-gauge]

[Illustration: Fig. 209. A more complete rain-gauge]