Compound lever Compound lever The compound lever is a simple machine operating on the premise that the resistance from one lever in a system of levers will act as power for the next, and thus the applied force will be amplified from one lever to the next (as long as the mechanical advantage for each lever is greater than one). Almost all scales use some sort of compound lever to work. Other examples include nail clippers and piano keys. A lever arm uses the fulcrum to lift the load using and intensifying an applied force. In practice, conditions may prevent the use
Lever frame Lever frame Mechanical railway signalling installations rely on lever frames for their operation to interlock the signals, track locks and points to allow the safe operation of trains in the area the signals control. Usually located in the signal box, the levers are operated either by the signalman or the pointsman. The world's largest lever frame (191 levers) is thought to have been in the Spencer Street No.1 signal box in Melbourne, Australia, which was decommissioned in 2008. The largest operational lever frame, meanwhile, is located at Severn Bridge Junction in Shrewsbury, England, and it contains 180 levers, although most