### Screw with Lever Arm

"The power is generally applied by a wheel or a lever, and moves through the circumfrence of a circle.…

### Compound Screw

Compound screws commonly used as clamps.

### Second Class Lever

A lever of the second class

### Second Class Lever

"A lever is an inflexible bar freely movable about a fixed axis called the fulcrum. If the weight is…

### Second-class Lever

"The second kind of lever is represented where W is the weight, L the lever, F the fulcrum, and P a…

### Second-class Lever

"Two men carrying a load between them on a pole is also and example of this [second class] kind of lever.…

### Second-class lever

"Second class lever." -Comstock 1850

### Second Class Lever

"A Lever of the Second Kind is one in which the weight is between the power and the fulcrum." —Quackenbos…

### Second Order of Lever

In the second order of levers, the weight is between the power and the fulcrum.

### See-saw

"A pracitcal application of a balance/lever is a see-saw." —Quackenbos 1859

"Railway Semaphore. a, lever, which operates both b, blade, and c, lantern." -Whitney, 1911

### Singer Sewing Machine

"Singer sewing-machine. a is the frame and cloth-plate or bed-plate; b, arm; c, treadle; e, pitman;…

### Shadoofs, Two Men Raising Water

"A contrivance extensively employed in Egypt and the East, generally for raising water. It consists…

### Simple Lever

"Any rod, or bar, which is used in raising a weight, or surmounting a resistance, by being placed on…

### Simple lever system

"Suppose that A is the lever, B the fulcrum, D the weight to be raised, and C the power. Let D by considered…

### Simple Lever System

"Suppose the weight, B to be sixteen pounds and suppose the fulrum to be placed so near it, as to be…

### Simple Lever System

"But let the fulcrum be moved along to the middle of the lever, with the weight of sixteen pounds still…

### Simple Machines

Illustrations showing the six mechanical powers: lever, wheel and axle, pulley, inclined plane, wedge,…

### Lever Spring Safety-valve

A form of spring safety-valve, in which a series of bent springs h h h are placed alternately in opposite…

### Newcomen Atmospheric Steam Engine

An illustration of Newcomen atmospheric steam engine. The boiler heats the water to build up steam in…

### Watt's Final Steam Engine Design

The illustration showing Watt's final steam engine design. The engine is fitted with series of rods…

### Steelyard

"The Steelyard is more portable then the ordinary balance. It consists of a lever, AB, moving round…

### Steelyard

"When bodies of unequal weight are supported by the arms of a lever, they will balance each other whenever…

### Steelyard

"The steelyard is a kind of balance, which, though not so sensitive as the one being described above,…

### Suction-pump

A suction-pump with the upward and downward movement of the piston being effected by means of a lever.

### System of Wheels

"System of Wheels.—As the wheel and axle is only a modification of the simple lever, so a system…

### Third Class Lever

A lever of the third class

### Third class lever

"A lever is an inflexible bar freely movable about a fixed axis called the fulcrum. If the power is…

### Third-class Lever

"In the third and last kind of lever, the weight is placed at one end, the fulcrum at the other end…

### Third Class Lever

"Third class lever." -Comstock 1850

### Third Class Lever

"A Lever of the Third Kind is one in which the power is between the weight and the fulcrum." —Quackenbos…

### Third Order of Lever

In the third order of levers, the power is between the weight and the fulcrum.

### Lever Safety Valve

An illustration of a lever safety valve. "Suppose the valve A is just suppose to open when the steam…

### Wheel and axle

"The wheel and axle consists of a wheel united to a cylinder in such a way that they may turn together…

### Wheel and Axle

"This figure represents the machine endwise, so as to show in what manner the lever operates. The two…

### Wheel and Axle with Rope and Bucket

"The wheel and axle consists of a wheel united to a cylinder in such a way that they may turn together…

### Wheel and Axle

"Considered as a lever, the fulcrum is at the common axis, while the arms of the lever are the radii…

### Ratchet Wheel

A wheel with pointed and angular teeth, against which a ratchet abuts, used either for converting a…