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The lever is operated by applying an input force F A at a point A located by the coordinate vector r A on the bar. The lever then exerts an output force F B at the point B located by r B. The rotation of the lever about the fulcrum P is defined by the rotation angle θ in radians. Archimedes lever, Engraving from Mechanics Magazine, published ...
a throttle lever or regulator, which controls the amount of steam entering the cylinders [3]: 75 : 82 a reversing lever or (US term) Johnson bar, which controls the timing of the admission of steam into the locomotive's cylinders. [3]: 65 This is required for two purposes. One is to reverse the locomotive's direction, e.g. when shunting.
The lever is a movable bar that pivots on a fulcrum attached to or positioned on or across a fixed point. The lever operates by applying forces at different distances from the fulcrum, or pivot. The location of the fulcrum determines a lever's class. Where a lever rotates continuously, it functions as a rotary second-class lever.
Simple machines are elementary examples of kinematic chains that are used to model mechanical systems ranging from the steam engine to robot manipulators. The bearings that form the fulcrum of a lever and that allow the wheel and axle and pulleys to rotate are examples of a kinematic pair called a hinged joint. Similarly, the flat surface of an ...
Compound levers can be constructed from first, second and/or third-order levers. In all types of compound lever, the rule is that force multiplied by the force arm equals the weight multiplied by the weight arm. The output from one lever becomes the input for the next lever in the system, and so the advantage is magnified.
Crank and slotted lever Quick Return mechanism (used in shapers) Fixed piston mechanism (used in hand pumps) Two revolute joints and two prismatic joints: It is denoted as PRRP, [2] and is constructed by connected two sliders with a coupler link. The doubler slider refers to all arrangements in this type. Examples of 2R2P linkages include:
These were once common for special functions in control systems, such as fire control mechanisms for guns on naval vessels [10] and mechanical analog computers. [ 11 ] An example of a cylindrical cam with two inputs is provided by a duplicating lathe , an example of which is the Klotz axe handle lathe, [ 12 ] which cuts an axe handle to a form ...
[21] [22] The handle near the outer edge of the rotary part makes the crank, [21] [23] [24] a human arm powering the rotation would be the connecting rod. [21] According to F. Lisheng and T. Qingjun, the hand-crank of the rotary quern was different from a crank, which was the combination of a hand-crank and a push-and-pull connecting rod by a ...