Transcriber’s Notes:
Underscores “_” before and after a word or phrase indicate _italics_
in the original text.
Equal signs “=” before and after a word or phrase indicate =bold=
in the original text.
Small capitals have been converted to SOLID capitals.
Illustrations have been moved so they do not break up paragraphs.
Typographical and punctuation errors have been silently corrected.
TRACTOR PRINCIPLES
THE ACTION, MECHANISM, HANDLING,
CARE, MAINTENANCE AND REPAIR
OF THE GAS ENGINE TRACTOR
BY
ROGER B. WHITMAN
AUTHOR OF
“MOTOR CAR PRINCIPLES,”
“GAS ENGINE PRINCIPLES,”
“MOTOR-CYCLE PRINCIPLES,”
ETC.
[Illustration]
FULLY ILLUSTRATED
D. APPLETON AND COMPANY
NEW YORK LONDON
1920
COPYRIGHT, 1920,
BY
D. APPLETON AND COMPANY
PRINTED IN THE UNITED STATES OF AMERICA
FOREWORD
The tractor of to-day is built in almost as many types and designs
as there are tractor makers, and is far from being as standard as
the automobile. There are tractors with one driving wheel, with two
driving wheels, with three and with four, as well as three arrangements
of the crawler principle; there are two-wheelers, three-wheelers and
four-wheelers; tractors that are controlled by pedals and levers and
tractors that are driven by reins.
Thus if a man who is competent to handle and care for one make is given
another make to run, he may be entirely at a loss as to how it works
and how it should be handled.
It is the purpose of this book to explain and describe all of the
mechanisms that are in common use in tractor construction, to the end
that the reader may be able to identify and understand the parts of
whatever make he may see or handle.
CONTENTS
PAGE
CHAPTER I
TRACTOR PRINCIPLES
Comparison between tractors and automobiles—What is
required for each—Advantage of understanding the
mechanism—No standard tractor design—Principal
parts of a tractor—Necessity for each 1
CHAPTER II
ENGINE PRINCIPLES
Power attained from heat—Combustible mixture—Principle
of engine operation—Combustion space—Gas engine
cycle—Dead strokes—Flywheel—Starting an
engine—Inlet stroke—Compression stroke—Importance
of compression—Ignition—Advance and retard of
ignition—Power stroke—Exhaust stroke—Production of
power—Vertical and horizontal engines—Firing order 9
CHAPTER III
ENGINE PARTS
Base—Bearings—Cylinders—Crankshaft—Piston—Connecting
rod—Wrist pin—Piston rings—Valves—Cam—Valve
mechanisms—Cooling system 30
CHAPTER IV
FUELS AND CARBURETION
Oxygen necessary for combustion—Forming a mixture—Rich and
poor mixtures—Carbon—Preignition— Carbureter—Spray
nozzle—Evaporation of fuels—Carbureter principles—
Extra air inlet—Effect of heat on mixture—Loading—
Strangler 52
CHAPTER V
CARBURETERS
Carbureter parts—Manifold—Action of carbureter—Float
feed—Kerosene and gasoline—Descriptions of
carbureters—Pump feed—Use of water in the
mixture—Application of heat—Fuel pumps—Air
cleaners—Governors 70
CHAPTER VI
IGNITION
Principle of ignition—Point of
ignition—Preignition—Advance and retard—Parts of
ignition system—Magnetism—Induction—Magneto—Action
of armature—Armature windings—Circuit
breaker—Circuit—Shuttle and inductor
armatures—Sparking current—Grounded circuit—
Magneto parts—Impulse starter 102
CHAPTER VII
BATTERY IGNITION SYSTEMS
Principle of spark coil—Windings—Timer—Atwater-Kent
system—Vibrator—Spark plugs 131
CHAPTER VIII
TRANSMISSION
Transmission parts—Clutches—Necessity for change speed
gear—High and low gear—Types of change speed
gears—Necessity for differential—Principle of
differential—Drives—Worm 143
CHAPTER IX
TRACTOR ARRANGEMENT
Tractor requirements—Tractor types—Engine position—
Front axles—Spring supports 167
CHAPTER X
LUBRICATION
Importance of lubrication—Effect of oil—Kinds of
oil—Effect of temperature on oil—Using the right
kind of oil—Burning point—Viscosity—Lubrication
charts—Oiling systems—Oil pumps—Mechanical oiler—
Oil cup—Grease cup 175
CHAPTER XI
TRACTOR OPERATION
Using a new tractor—Breaking in—Daily
inspection—Driving—Shifting gears—Driving on
hills—Using the engine as a brake—Cold weather
conditions—Starting in cold weather—Protection
against freezing—Starting a tractor 201
CHAPTER XII
ENGINE MAINTENANCE
Fuel system and carbureter—Carbureter adjustment—Dirt
in the fuel—Running on kerosene—Care—Magneto and
ignition system—Care of magneto—Smoothing platinum
points—Adjustment—Timing a magneto—Testing a
magneto—Ignition trouble—Compression—Testing
for compression leaks—Valve grinding—Valve
timing—Carbon—Removing carbon 213
CHAPTER XIII
LOCATING TROUBLE
Engine will not start—Engine loses power—Engine
stops—Engine misses—Engine starts; but stops—Engine
overheats—Engine smokes 245
CHAPTER XIV
CAUSES OF TROUBLE
Troubles and their causes in tabular form 259
INDEX 261
ILLUSTRATIONS
FIG. PAGE
1 The Gas Engine Cycle 15
2 1-cylinder power diagram 21
3 2-cylinder power diagram 22
4 2-cylinder power diagram, 180 shaft 24
5 H. D. O. power diagram 26
6 4-cylinder power diagram 27
7 2-cylinder crank shaft 31
8 4-cylinder crank shaft 32
9 Half of a plain bearing 32
10 Connecting rod bearings 33
11 Piston complete and in section 34
12 Wrist pin fastenings 36
13 Valve 38
14 Action of cam 39
15 “Twin City” tractor engine 41
16 “Hart-Parr” valve mechanism 43
17 “Hart-Parr” engine 45
18 “Oil-Pull” engine 47
19 Horizontal double opposed engine 49
20 “Monarch” engine 51
21 Principle of carburetor 59
22 Principle of extra air inlet 64
23 “Kingston” carburetor, model L 72
24 “Kingston” carburetor, model E 75
25 “Kingston” carburetor, dual model 77
26 “E-B” carburetor 79
27 “E-B” carburetor, side view 81
28 Pump-fed carburetor 82
29 “Titan” carburetor 84
30 Pump-fed carburetor with two fuel nozzles 85
31 “Hart-Parr” mixture heater 87
32 “Twin City” manifold 88
33 Fuel pump 90
34 “Avery” fuel connections 92
35 “Oil-Pull” fuel system 93
36 Air washer 95
37 Air strainer 96
38 “E-B” governor 97
39 “Case” governor 98
40 “Hart-Parr” governor 99
41 Vertical governor 101
42 Armature 107
43 Flow of magnetism through armature core 108
44 One complete revolution of the armature 111
45 Connections of Bosch magneto 112
46 “K-W” inductor 115
47 “K-W” inductor in three positions 117
48 “Dixie” inductor 118
49 Three positions of “Dixie” inductor 120
50 “Bosch” circuit breaker 121
51 “K-W” circuit breaker 122
52 “Bosch” magneto in section 126
53 “K-W” magneto in section 129
54 Magnetism in a copper wire 132
55 Magnetism from electricity 133
56 Principle of spark coil 134
57 “Atwater-Kent” ignition system 136
58 Vibrator coil ignition system 139
59 Spark plug 141
60 Internal clutch 144
61 Plate clutch 147
62 Principle of sliding gear 155
63 Principle of jaw clutch change speed gear 157
64 “I. H. C.” chain drive, showing differential 162
65 “Case” rear axle 163
66 “Oil-Pull” rear axle 164
67 Driving worm 165
68 Tractor arrangement 168
69 Tractor arrangement 169
70 “Gray” tractor 171
71 Types of front axles 172
72 Spring support 173
73 “Mogul” oiling diagram 180
74 “Illinois” oiling diagram 183
75 End of “Twin City” connecting rod 185
76 Wrist pin lubrication 186
77 Force feed oiling system of “Gray” engine 187
78 Oil pump 188
79 “E-B” oil pump 189
80 Oil pump with hollow plunger 190
81 Methods of preventing oil leaks 191
82 “Titan” lubricator 192
83 “I. H. C.” method of oiling crank pins 193
84 “Hart-Parr” oiling system 194
85 Oil cup 195
86 Proper use of a grease cup 196
87 “Titan” 10-20 oiling diagram 198
88 “International” oiling diagram 199
89 Grinding valve in engine with fixed head 231
90 Grinding valve in detachable head 233
91 Grinding valve in detachable seat 234
92 Valve seat cutter 235
93 “Holt” valve arrangement 236
94 Valve timing, using marks on flywheel 238
95 Valve timing 239
TRACTOR PRINCIPLES
CHAPTER I
TRACTOR PRINCIPLES
While tractors and automobiles are the same in general principles,
there is a wide difference between them in design, construction, and
handling, due to the differences in the work that they do and in the
conditions under which they do it.
An automobile is required to move only itself and the load that it
carries. While it can run over rough roads, these must be hard enough
to support it; on soft ground it will sink in and be unable to get
itself out. It can make great speed over smooth, level roads; but only
rarely do road and police conditions permit it to run its fastest for
more than a few minutes at a time. For the greater part of its life it
develops only a portion of the power of which it is capable.
A tractor, on the other hand, is intended not to carry, but to haul.
It must run and do its work on rough hillsides, soft bottoms, or any
other land where it is required to go. Instead of developing speed it
develops pulling power, and must be able to develop its full power
continuously.
Appearance and comfort count for a great deal in an automobile, and
much attention is devoted to making it noiseless and simple to manage.
These things do not apply in a tractor, which is a labor-saving and
money-making machine, valuable only for the work that it can do. There
is no question of upholstery or nickel-plating; all that is wanted is a
machine that will do the required work with the least possible cost of
operation.
As is the case with any kind of machine that is purchased as a
money-maker, its cost should be as low as is consistent with its
ability to do its work. Any extra cost for accessories, or finish, or
other detail, is wasted unless it permits the machine to do more work,
or, by making the operator more comfortable, allows him to run the
machine for a longer stretch of time or with greater efficiency.
It may be taken for granted that any tractor will run and will do its
work with satisfaction, provided it is sensibly handled and cared for.
Far more troubles and breakdowns come from careless handling and from
neglect than from faulty design and material. A tractor that is running
and doing its work is earning a return on the money invested in it;
when it is laid up for repairs there is not only a loss of interest on
the investment, but a loss of the value of the work that it might be
doing.
To keep a tractor running is a matter only of understanding and of
common sense; common sense to realize that any piece of machinery needs
some degree of care and attention, and understanding of where the care
and attention should be applied. The more thoroughly a tractor operator
understands his machine, the more work he will be able to get out of
it, and the more continuously it will run. This is only another way of
saying that understanding and knowledge pay a direct return in work
done and money earned.
In the early days of the automobile there were as many types of cars
as there were manufacturers. As time has gone on, the unsatisfactory
ideas have been weeded out, and automobiles have approached what may be
called a standard design.
At the present time, tractor designs are varied, and it is hardly
possible to speak of any type as standard. The reason for this lies in
the fact that many manufacturers start with a design for one special
part, and build the tractor around it.
For example, a manufacturer may develop a method of driving the wheels
that he feels is especially good for tractor work. In applying it he
may find that the engine must be so placed on the frame that when the
power pulley is in position the belt will interfere with the front
wheels unless they are small; he therefore uses small front wheels, and
advocates them for tractors.
Another manufacturer with a patent steering gear may be able to place
the power pulley so that there is ample clearance for the belt; he
finds that by using high front wheels he can get a better support for
the frame, and therefore claims that high front wheels are an advantage.
Other designs may be based on having three wheels, or two; advantages
are claimed for each type, and each type undoubtedly has them.
The selection of a tractor is based on one’s own experience or on
that of neighbors, or on the ability of the salesman to bring out the
advantages of the make that he sells; but when the tractor is bought
and delivered, its ability to do the work promised for it depends
solely on the care with which it is handled and looked after.
Whatever the design of a tractor may be, there are certain parts that
it must have in order to do the work required of it. These parts, or
groups of parts, are as follows:
=Engine.=—This furnishes the power by which the tractor operates.
=Clutch.=—By means of a clutch the engine may be connected with the
mechanism, so that the tractor moves, or it may be disconnected, so
that it may run without moving the tractor.
=Change Speed Gear.=—As will be explained in later chapters, an engine,
in order to work most efficiently, should run at a fixed speed; the
tractor should be able to run fast or slow, according to conditions.
A change speed gear is therefore provided, by which the speed of the
tractor may be changed, although there is no change in the speed of the
engine.
=Drive.=—The drive is the mechanism that applies the power of the
engine to the wheels, and makes them turn.
=Differential.=—When a tractor makes a turn, the outside wheels cover
a larger circle than the inside wheels, and therefore must run faster
in order to get around in the same time. It is usually the case that
the power of the engine is applied to both driving wheels; if both were
solid on the axle, like the wheels of a railroad car, one would be
forced to slip when making a turn, which would waste power. By applying
a differential, the engine can drive both wheels, but the wheels may
run at different speeds when conditions require it.
The clutch, change speed gear, drive and differential form the
_transmission_.
=Steering gear.=—By means of the steering gear the direction in which
the tractor moves may be changed.
=Supports.=—A tractor moves on broad-tired wheels, or on crawlers,
which are so formed that they grip the ground and do not slip. They
give so broad a support that even on soft ground the weight of the
tractor will not pack the soil sufficiently to injure it as a seed bed.
=Frame.=—The frame is the foundation of the tractor, and holds the
parts in the proper relation to each other. It is usually made of
channel steel, the parts being bolted to it; in some tractors, however,
the parts are so attached to each other that they form their own
support, and no other frame is needed.
Tractor manufacturers make these parts in different ways; all
accomplish the same result, but do it by different methods. The main
principles are much the same, and should be known and understood. They
are described and explained in the succeeding chapters.