The elements of mechanism - Tate
THE ELEMENTS OF MECHANISM
Containing a familiar explanation of the construction of various kinds of machinery, &c.
BY THOMAS TATE
LONDON, LONGMAN, BROWN, GREEN, AND LONGMANS, 1851
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The elements of mechanism
CONTENTS
CHAPTER I
- Motion
- Angular Velocity
CHAPTER II
- Machines in general
- Advantages and Uses of Machines
- The Parts of a Machine
- Elementary Forms of Mechanism
CHAPTER III
- Link-work. Levers
- Oblique Lever
- Cranks
- Bent Lever
- Velocity Ratio in a General Form of Link-work
CHAPTER IV
- Cords, &c, producing Motion by wrapping Contact
- Pulleys, etc
- The Endless Cord
- Systems of Pulleys
- Guide Pulleys
- Forms of Wrapping Connectors
- Wheel and Axle, with Cord Connectors
- The Windlass. The Capstan
- The Compound Wheel and Axle
- Speed Pulleys
- The Fusee of a Watch
- To produce a variable Motion
- Angular Velocities of two eccentric Wheels
CHAPTER V
- Wheel-work producing, by rolling Contact, Wheel-motions
- Spur Wheels
- Trains of Wheel- work
- Annular Wheels. Idle Wheels
- Teeth of Wheels. Pitch Circles, &c
- Forms of Wheel- work when the Axes are not parallel
- Crown Wheels. Face Wheel and Lantern
- Bevel Wheels
- Intermediate Bevel Wheels
- Rack and Pinion
- Shafts and Axes. Coupling
- Universal Joint
- Engagement and Disengagement of Machinery
- Gudgeons
- Friction Wheels
- Concentric Wheels
- Ratchet Wheels
- Intermittent Motions in Wheels
- Variable Motions produced by rolling Contact
- Wheels used in Silk Mills. Roemer's Wheels
- The eccentric Crown Wheel
CHAPTER VI
- Sliding Pieces producing, by sliding Contact, sliding Motions
- Inclined Plane
- The Wedge
- Cambs and Wipers
- The Swash Plate
- Escapements. Crown-wheel and Anchor Escapements
- The Screw
- The common Press
- The Compound Screw
- The Differential Screw
- The Endless Screw
- Compound Machine
- Conical Screw
CHAPTER VII
- Mechanism considered in relation to the Objects proposed to be effected
- Mechanism for regulating and accumulating Motion
- The Governor
- The Water Regulator
- The Regulating Damper
- The Pendulum
- Machines for accumulating Work. The Fly Wheel, &c.
- Mechanism for modifying Motion
- To change a continuous circular Motion into a reciprocating rectilinear one, and the converse
- Various Pieces of Mechanism
- To change a reciprocating circular Motion into a continuous circular one, and conversely
- The Treadle Board. The Crank and Connecting Rod. The Sun and Planet Wheel
- The Eccentric Wheel
- The Mangle Motion
- Intermittent Motion
- To change a reciprocating circular Motion into a reciprocating rectilinear one, and conversely
- Rack and Pinion. Arched-head and Chain, &c.
- Watt's Parallel Motion
- White's Parallel Motion
CHAPTER VIII
- Various Kinds of Machinery
- Machine for raising Water by means of Buckets from deep Wells
- The Horse Mill
- The Potter's Lathe
- The Crab. The Hand Jack
- The Gib Crane
- The Foot Lathe
- Self-acting Slide Rest
- Machines for cutting Screws
- The Hand Drill
- Shears for cutting Metal
- The Dredging Machine
- The Pile Engine
- The Hand Mill for grinding Com
- The Saw Mill
- Spinning Machines
- The Smoke Jack
- The Clock
CHAPTER IX
- PUMPS AND OTHER HYDRAULIC ENGINES
- The Common Pump
- The Forcing Pump. Forcing Pump with Air Chamber
- Double-acting Pump
- The Fire Engine
- A Ship Pump working with Parallel Motion
- The Chain Pump
- A Pump wrought by a double Crank
- Pumps for raising Water from Dykes
- The Archimedean Screw
- Hydraulic Ram
- Suction Ram
- Machines in which Water is the Prime Mover
- Water Wheels
- Barker's Mill
CHAPTER X
- The Steam Engine. Savery's Engine
- Newcomen's Engine, with the Crank and Fly Wheels
- Watt's Engine. The Condenser, &c.
- Valves for regulating the Distribution of the Steam
- Slide Valves. Locomotive Engine with the common Slide Valve
- The D-valve
- The four-way Cock, with its Application
- Leupold's High-pressure Engine
- Appendages of the Steam Boiler
- The Safety Valve. The Steam Gauge
- The Water Gauge
- Forms of Boilers
- General View of a Double-acting Condensing Engine
CHAPTER XI
- Problems on Mechanism
- On Levers, Pulleys, Wheels and Axles, &c.
- On Speed Pulleys, &c.
- On Trains of Wheel-work
- On Pitch Circles, &c &c
- General Formula relative to a Compound Machine
- Construction of Watt's Parallel Motion
- Calculation relative to Crank Pumps, the Crab, &c
- Investigation relative to the Screw-cutting Machine
- On the Saw Mill
- On the Chain Pump
- To find the Velocity Ratio of the Crank and great Beam
- On the Motion of the Slide Valve
CHAPTER II - MACHINES IN GENERAL
Advantages and Uses of Machines. - The following are some of the most obvious advantages and uses of machinery:
1. In accumulating power, or exerting forces too great for human power. With the coining engine a single man can produce the impression of the die upon the metal, which the unaided pressure, exerted by a hundred men, could not effect. With the common crane one man can raise a weight which would require several horses.to draw.
2. In regulating the distribution of power and motion. Uniformity in the rate of a machine is in many cases essential to its successful application. The pendulum of a clock, the governors of steam engines and water-mills, &c., are examples of regulators of power and motion.
3. In increasing or decreasing velocity. In the common spinning-wheel, the foot applied to the treadle, can only be conveniently moved with a certain speed, but a much greater motion must be given to the part which twists the flax. Again, in the common smoke-jack, the motion communicated to the vane wheel is much too great for the purpose requiredthis motion is therefore transmitted through a series of wheels which reduce it to the requisite speed.
4. In changing the direction of motion. By turning the handle of a windlass, a man raises a bucket from a well. The piston of a steam-engine moves up and down in a vertical direction, or, in other words, it has a reciprocating rectilinear motion, .but by the intervention of mechanism this motion is made to turn wheels, to pump water, or in fact to produce the various kinds of motion required in our arts and manufactories.
5. In prolonging the action of forces. The few seconds which we take in winding up a watch, are sufficient, by the aid of wheels, to produce a force which will continue in action for 24 hours.
6. In registering operations. Familiar examples of this are exhibited in the turn-stile of our bridge keepers, and in the gas-meter.
7. In effecting a uniformity and precision in the work to be done. With the lathe an ordinary workman can turn a piece of metal perfectly cylindrical, which would baffle the skill of the most perfect mechanic to produce without the aid of such machinery.
8. In economising time and labour. Twenty years ago, the stage coach took 25 hours in travelling from London to York, but by the railway carriage the journey may be performed in one-fifth of that time. The steam printing press is another remarkable instance of the same kind.
12. Application op Forces to Machines. - Forces, applied to give motion to machinery, are developed by various means: 1. By animals. 2. By the descent of weights. 3. By the fall of water. 4. By the action of springs. 5. By the expansion and pressure of fluids. 6. By electricity and magnetism.
These forces have four modes of action : 1. In the form of simple pressure, as in the case of pressure applied to the arm of a lever, or when a fluid acts upon a piston. 2. In the form of a thrust or push, as in the case of a rod being pushed forward to give motion to another rod or some other piece of mechanism. 3. In the form of a drawing or pulling force, as in .the case of wheels being moved by cords or straps. 4. In the form of a stroke, as in the case of a wedge being struck by a mallet.
The nature of the mechanism depends in some measure upon the manner in which the forces are applied to the machine. Thus, when the foot is used to turn a lathe, the force is applied to a foot-board or treadle; when a horse is employed to raise coals from a pit, the animal is made to run in a circular path, and thus motion is given to a large horizontal drum wheel round which the pit rope coils. In the first instance a vertical reciprocating motion is converted, by the intervening mechanism, into a continuous circular motion : and, in the last instance, a circular horizontal motion is converted into a rectilinear vertical one.
13. The Fasts of a Machine. A machine consists of three important parts: 1. The parts which receive the work of the moving power, - these may be called receivers of work. 2. The parts which perform the work to be done by the machine, - these may be called working parts or more simply operators. 3. The mechanism which transmits the work from the receivers to the working parts or operators, - these pieces of mechanism may be called communicators of work.
The form of the mechanism or communicators must always be determined from the relation subsisting between the motions of the receivers and operators.
DOWNLOAD FREE BOOK:1. In accumulating power, or exerting forces too great for human power. With the coining engine a single man can produce the impression of the die upon the metal, which the unaided pressure, exerted by a hundred men, could not effect. With the common crane one man can raise a weight which would require several horses.to draw.
2. In regulating the distribution of power and motion. Uniformity in the rate of a machine is in many cases essential to its successful application. The pendulum of a clock, the governors of steam engines and water-mills, &c., are examples of regulators of power and motion.
3. In increasing or decreasing velocity. In the common spinning-wheel, the foot applied to the treadle, can only be conveniently moved with a certain speed, but a much greater motion must be given to the part which twists the flax. Again, in the common smoke-jack, the motion communicated to the vane wheel is much too great for the purpose requiredthis motion is therefore transmitted through a series of wheels which reduce it to the requisite speed.
4. In changing the direction of motion. By turning the handle of a windlass, a man raises a bucket from a well. The piston of a steam-engine moves up and down in a vertical direction, or, in other words, it has a reciprocating rectilinear motion, .but by the intervention of mechanism this motion is made to turn wheels, to pump water, or in fact to produce the various kinds of motion required in our arts and manufactories.
5. In prolonging the action of forces. The few seconds which we take in winding up a watch, are sufficient, by the aid of wheels, to produce a force which will continue in action for 24 hours.
6. In registering operations. Familiar examples of this are exhibited in the turn-stile of our bridge keepers, and in the gas-meter.
7. In effecting a uniformity and precision in the work to be done. With the lathe an ordinary workman can turn a piece of metal perfectly cylindrical, which would baffle the skill of the most perfect mechanic to produce without the aid of such machinery.
8. In economising time and labour. Twenty years ago, the stage coach took 25 hours in travelling from London to York, but by the railway carriage the journey may be performed in one-fifth of that time. The steam printing press is another remarkable instance of the same kind.
12. Application op Forces to Machines. - Forces, applied to give motion to machinery, are developed by various means: 1. By animals. 2. By the descent of weights. 3. By the fall of water. 4. By the action of springs. 5. By the expansion and pressure of fluids. 6. By electricity and magnetism.
These forces have four modes of action : 1. In the form of simple pressure, as in the case of pressure applied to the arm of a lever, or when a fluid acts upon a piston. 2. In the form of a thrust or push, as in the case of a rod being pushed forward to give motion to another rod or some other piece of mechanism. 3. In the form of a drawing or pulling force, as in .the case of wheels being moved by cords or straps. 4. In the form of a stroke, as in the case of a wedge being struck by a mallet.
The nature of the mechanism depends in some measure upon the manner in which the forces are applied to the machine. Thus, when the foot is used to turn a lathe, the force is applied to a foot-board or treadle; when a horse is employed to raise coals from a pit, the animal is made to run in a circular path, and thus motion is given to a large horizontal drum wheel round which the pit rope coils. In the first instance a vertical reciprocating motion is converted, by the intervening mechanism, into a continuous circular motion : and, in the last instance, a circular horizontal motion is converted into a rectilinear vertical one.
13. The Fasts of a Machine. A machine consists of three important parts: 1. The parts which receive the work of the moving power, - these may be called receivers of work. 2. The parts which perform the work to be done by the machine, - these may be called working parts or more simply operators. 3. The mechanism which transmits the work from the receivers to the working parts or operators, - these pieces of mechanism may be called communicators of work.
The form of the mechanism or communicators must always be determined from the relation subsisting between the motions of the receivers and operators.
The elements of mechanism
