[Footnote: From a paper read before the "Technischen Verein" of New
York, May 28, 1887.]
By CHAS. A. SCHIEREN.
The old saying that "there is nothing new under the sun" may well be
applied to leather link belting. It is generally believed that these
belts are of recent invention, but that is an error. They are over
thirty years old.
Mr. C.M. Roullier, of Paris, experimented that long ago with small
leather links one and one-half inches long by three-quarters of an inch
wide. These links had two small holes at equal distances apart, and were
joined with iron bolts, which were riveted at the ends, thus making a
perfectly flat surface, and in that way forming a belt entirely of
leather links.
Mr. Roullier's idea was to economize; he therefore utilized the material
left over from the manufacture of flat belting. He perfected his belt
and came to this country in 1862, when he patented the article here and
tried to introduce it. At first it produced quite a sensation, and many
tests were made, but it was soon found that Roullier's belts were not
suited to running our swift motion machinery, and they were therefore
abandoned as impracticable.
Mr. Roullier then introduced his invention into England, where he met
with some success, as his belt was better suited to English slow motion
machinery.
These belts are now largely used in England, many good improvements have
been made in them, and almost every belt maker in Great Britain
manufactures them.
Mr. Jabez Oldfield, of Glasgow, has the reputation of making the best
and most reliable link belt in Great Britain. He has also the reputation
of being the originator of these belts. This is, however, an error, the
credit of the invention belonging, as we have said, to Mr. Roullier.
Mr. Oldfield, nevertheless, has invented many useful machines for
cutting and assorting the links. He has also introduced improved methods
for putting the links together.
For more than twenty years after Mr. Roullier's visit, nothing was done
with leather link belting in this country.
In 1882, however, Mr. N.W. Hall, of Newark, N.J., patented a link belt,
composed of leather and steel links. His method was to place a steel
link after every third or fourth leather one, in order to strengthen the
belt. In practical use this belt was found to be very defective, because
the leather links soon stretched, and thus all the work had to be done
by the steel links. The whole strain coming thus upon the steel links,
they in course of time cut through the bolts and thus broke the belt to
pieces. So this invention proved worthless.
In 1884 a Chicago belt company obtained a patent on another style of
link belt. In this belt all the little holes in the links were lined
with metal, similar to the holes in laced shoes. This produced an effect
similar to that produced by Hall's patent. The metal lining of the holes
cut the bolts into pieces by friction and thus ruined the belt.
Therefore this patent proved a failure also.
After all these failures it fell to our lot to improve these belts so
that they may now be worked successfully on our American fast running
machinery. During the past two years we have made and sold over five
hundred leather link belts, which are all in actual use and doing
excellent service, as is proved by many testimonials which we have
received.
Our success with these belts has been so surprising that we think we
have found, at last, the long looked for "missing link," not in
"Darwinism," however, but in the belting line. We prophesy a great
future for these belts in this country.
How have we attained such success? First: We found that Roullier made a
mistake in using leather offal, as, in the links of an _iron chain_, if
one link is weak or defective, the whole chain is worthless, so in link
belts, if one or two links are weak or made of poor material, the whole
belt is affected by them. It is therefore of vital importance that only
the best and most solid leather be used in making the links; second, the
leather must be made very pliable, but at the same time its toughness
and tenacity must not be injured, or it will stretch and break.
[Illustration: FIG 1.]
These things are of great importance, and are the principal reasons for
the failures of all former efforts. The leather which Roullier used was
stiff, hard, and husky. He believed that the harder the link the greater
its tensile strength, but upon actual test this was found to be a fatal
error.
Our leather links are saturated with a mixture of tallow, neatsfoot oil,
etc. This makes them very pliable and increases their toughness, so that
they will stand a strain three times as great as a piece of hard rolled
sole leather.
In manufacturing this belt, the joining together is important. The links
must be accurately assorted as to thickness, and the outer links
countersunk, to admit the bolt. Then the most valuable improvement of
all is our "American joint" (see Fig. 1).
By close inspection you will observe that it is absolutely necessary to
use half length bolts for the width of wide leather link belts.
Examine Figs. 2 and 3. In the latter you will notice one length of bolt
placed on a round faced pulley. That belt must either bend or break, and
in any case it will not give satisfaction; but, on the other hand,
examine Fig. 2; here two half length bolts are used, and ingeniously
joined in the center. It gives just pliability enough to lay the belt
flat upon the pulley. We experimented for some time before perfecting
this important improvement.
We also took out four patents for different methods of joining, but
abandoned them all and adopted the "American joint" system (Fig. 1) as
the most efficient, simple, and reliable. It gives the belt an unbroken
flat surface and is far superior to anything so far introduced for that
purpose.
We have not stopped at _flat_ link belting, but have turned our
attention to manufacturing round solid leather link belting, and believe
that we have almost attained perfection in that line. As the
illustrations clearly show, there is quite a demand for inch and upward
solid round belting, and the difficulty always has been to join such a
belt together. All steel hooks, etc., do not seem to satisfy. This, our
new invention, is so simple that it hardly needs explanation. A belt of
this kind can be taken apart in a short time, and shortened or
lengthened at pleasure.
Now, Mr. President and gentlemen, I shall be glad to answer any
questions in reference to these link belts, or give any further
explanation you may desire.
Question.--Can these link belts be used on dynamos for electric lights?
Answer.--Yes. In England they are used almost exclusively on dynamos.
However, they run only 700 revolutions per minute there, whereas our
slowest dynamo runs 1,100.
[Illustration: Fig. 2.]
Quest.--Would you advise link belts for high rate of speed?
Ans.--No; they give better results on slow running machinery.
Quest.--Have these belts any special advantage over flat leather
belting?
Ans.--Yes, decidedly. When belts are run half crossed, or what is termed
quarter turn, it is very hard to make flat belts lie perfectly even on
the pulleys. These link belts, however, cover the entire face of the
pulley (see illustration), and therefore are superior for that purpose.
[Illustration: Fig. 3.]
Quest.--Why do they give better results when run slow?
Ans.--Partly because of their great weight over ordinary belting, also
their grip power is stronger when run slow. No belt is superior to them
for slow, hard working machinery.
Quest.--Are they more expensive than ordinary flat belting?
Ans.--Not when compared to the work they can accomplish.
[Illustration]
Quest.--Can they be run in wet places, such as mines, etc.?
Ans.--Yes; by waterproofing the leather, no cement being used as in flat
belts. The links can be made positively waterproof. We have furnished
paper mills, tanneries and bleacheries, and other exposed places with
waterproof link belts, and all have been entirely satisfactory so far.
Quest.--Can they be run on ordinary flat pulleys?
Ans.--Yes; our "American joint" link belt can be run on any straight or
rounded pulley, whether made of iron, paper, or wood, and being all
endless they run much smoother than other belting.
[Illustration: ENGLISH HINGE JOINT:]
Quest.--How are they made endless?
Ans.--By a very simple process (see illustration), and takes almost less
time than lacing a flat belt. All that is necessary is to take both ends
and interlock the links, then pass the bolt through and rivet it, and
when you wish to shorten the belt proceed likewise: File off the end of
the bolt and take out, or add rows of links at pleasure and rejoin it
again.
[Illustration: Fig. 4 is a complete round link belt.]
Quest.--What is the relative strength of a link belt compared to flat
belting?
Ans.--Nothing definite has yet been ascertained. We are preparing a
table showing results, and so far we can report that they can stand
about twice the strain of double flat belts. A four inch link belt one
inch thick is able to do the work of an eight inch flat double belt.
[Illustration: Fig. 5 is a side view.]
Quest.--Explain the advantage of your American joint over the English
hinge.
Ans.--The American joint gives a perfect unbroken surface of entire
width of belt, whereas the English hinge joint makes two half widths,
and whenever a sudden change of power occurs and the belt runs half way
off the pulley, it will catch at the edge and tear everything to pieces.
[Illustration: Fig. 6 is an end view.]
Quest.--Have you a table or schedule of their weight per square foot?
Ans.--Yes. The following is as near as we can estimate the weight of
leather link belting per square foot:
1 inch thick, about 5 lb. per sq. ft.
7/8 " " " 4½ " " "
3/4 " " " 4 " " "
5/8 " " " 3½ " " "
Upon motion a vote of thanks was passed, and the paper read ordered to
be printed.
[Illustration: Fig. 7 is a single link.]
* * * * *
A NEW PROCESS OF CASTING IRON AND OTHER METALS UPON LACE, EMBROIDERIES,
FERN LEAVES, AND OTHER COMBUSTIBLE MATERIALS.
[Footnote: Abstract of a paper read before the Franklin Institute,
April, 1887.--_J.F.I._]
By A.E. OUTERBRIDGE, JR.
The art of making charcoal--if, indeed, so crude a process is worthy of
being dignified by the name of an art--dates back to a remote antiquity,
and has been practiced with but little change for hundreds of years. It
is true that some improvements have been recently made, but these relate
to the recovery of certain volatile by-products which were formerly
lost.
Every one is familiar with the appearance and characteristics of
ordinary charcoal, yet I hope to show you this evening that we still
have something new to learn about its qualities and the unexpected
practical uses to which it may be applied.
We commonly regard charcoal as a brittle, readily combustible substance,
but we have before us specimens in which these qualities are
conspicuously absent. Here is a piece of carbonized cotton sheeting,
which may be rolled or folded over without breaking, and, as you see,
when placed in the flame of a Bunsen burner, the fibers may be heated
white hot in the air, and when removed from the flame, the material
shows no tendency to consume. Here, again, we have a piece of very fine
lace, which has been similarly carbonized, and displays the same
qualities of ductility and incombustibility.
These carbonized fabrics may be subjected to much more severe tests with
impunity; and when I tell you that they have been exposed to a bath of
molten iron without injury, you will readily admit that they possess
some qualities not ordinarily associated with charcoal. When removed
from the mould in which they were placed after the iron casting had
cooled, not a single fiber was consumed, but _upon the face of the
casting there was found a sharp and accurate reproduction of the design,
thus forming a die_. This die may be used for a variety of purposes,
such as embossing leather, stamping paper, sheet metal, etc., or for
producing ornamental surfaces upon such castings.
Some of the carbonized fabrics displayed upon the table are almost as
delicate as cobwebs, and one would naturally suppose that when a great
body of molten metal is poured into a mould in which they are placed,
they would be torn to fragments and float to the surface even though
they were unconsumed, yet such is not the case. I have found in practice
that the most delicate fabrics may be subjected to this treatment
without danger of destruction, and that no special care is needed either
in preparing the mould or in pouring the metal.
By the aid of the megascope, the enlarged images of some of these
castings, showing the delicate tracery of the patterns, will now be
projected upon the screen, and you can all see how perfectly the design
is reproduced.
In these experiments, the mould was made in "green sand" in the ordinary
manner, and the fabric laid smoothly upon one face, being cut slightly
larger than the mould, in order that it might project over the edge, so
that when the moulding flask was closed, the fabric was held in its
proper position. As the molten metal flowed into the mould, it forced
the fabric firmly against the sand wall, and when the casting was
removed, the carbonized fabric was stripped off from its face without
injury. In this way several castings have been made from one carbonized
material.
These castings are as sharp as electrotypes, whether made of soft fluid
iron or of hard, quick-setting metal. This peculiarity is owing to the
affinity between molten iron or steel and carbon. The molten metal tends
to absorb the carbon as it flows over it, thus causing the fabric to hug
the metal closely. It is somewhat analogous to the effect of pouring
mercury over zinc. You know that when mercury is poured upon a board, it
runs in a globular form, it does not "wet" the board, so to speak; but
when poured upon a plate of clean zinc, it flows like water and wets
every portion of the zinc, or, as we say, it amalgamates with the zinc.
So when molten iron is poured into an ordinary sand mould, which has
been faced with this refractorily carbonized fabric, it wets every
portion of it, tending to absorb the carbon, and doubtless would do so
if it remained fluid long enough, but as the metal cools almost
immediately, there is no appreciable destruction of the fibers.
The casting which I shall now exhibit represents a very interesting and
novel experiment. In this case, the piece of lace, having open meshes a
little larger than a pin's head, instead of being laid upon one face of
the mould, was suspended in it in such a way as to divide it into two
equal parts. Two gates or runners were provided, leading from the
"sinking head" to the bottom of the mould, one on each side of the lace
partition. The molten iron was poured into the sinking head, and flowing
equally through both runners, filled the mould to a common level. The
lace, which was held in position by having its edges embedded in the
walls of the mould, remained intact. When the casting was cold, it was
thrown upon the floor of the foundry and separated into two parts, while
the lace fell out uninjured, and the pattern was found to be reproduced
upon each face of the casting.
The question naturally arises, Why did not the iron run through the
holes and join together? The answer may be found in the fact that the
thin film of oxide of iron, or "skin," as it is popularly called, which
always forms on the surface of molten iron, was caught in these fine
meshes, and thus prevented the molten metal from joining through the
holes. I have repeated the experiment a number of times, and find that
the meshes must be quite small (not over one fiftieth of an inch),
otherwise the metal will reunite.
I think that this observation explains the cause of many obscure flaws
found in castings, sometimes causing them to break when subjected to
quite moderate strains. We frequently find little "cold shot," or
metallic globules, embedded in cast iron or steel, impairing the
strength of the metal, and it has long been asked, "What is the cause of
this defect?" The pellicles have been carefully analyzed, under the
supposition that they might be alloys of iron and nickel, or some other
refractory metal, but the analysis has failed to substantiate this
theory. Is it not probable that in the process of casting, little drops
of molten metal are sometimes splashed out of the stream, which
immediately solidify and become coated with a skin of oxide, then
falling back into the stream of rapidly cooling metal, they do not
remelt, neither do they weld or amalgamate with the mass, owing to this
protective coating, thus forming dangerous flaws in the casting?
The process of carbonizing the delicate fabrics, leaves, grasses, etc.,
is as follows: The objects are placed in a cast iron box, the bottom of
which is covered with a layer of powdered charcoal or other form of
carbon, then another layer of carbon dust is sprinkled over them, and
the box is covered with a close fitting lid. The box is next heated
gradually in an oven, to drive off moisture, and the temperature slowly
raised until the escape of blue smoke from under the lid ceases. The
heat is then increased until the box becomes white hot. It is kept in
this glowing condition for at least two hours. It is then removed from
the fire, allowed to cool, and the contents are tested in a gas flame.
If they have been thoroughly carbonized, they will not glow when removed
from the flame, and the fibers may even be heated white hot before
consuming.
Of course, the method employed to carbonize the materials is suspectible
of variation, but the scientific principles involved are unchangeable,
viz.:
(1) Partial exclusion of air and substitution therefor of a carbon
atmosphere.
(2) Slow heating to drive off moisture and volatile elements.
(3) Intense and prolonged heating of the partly charred objects to
eliminate remaining foreign elements, and to change the carbon from the
combustible form of ordinary charcoal to a highly refractory condition.
[Illustration]
NOTE.--Fig. 1 is photographed from a white iron casting made upon
carbonized coarse lace; the lower portion of the plate shows the lace
embedded in the iron. Fig. 2 is a casting in gray iron upon lace laid on
an iron plate. Fig. 3 is a casting in hard iron upon lace laid on dand.
Fig. 4 is a casting in gray iron upon a piece of thin summer dress goods
with machine embroidery.
* * * * *