Lever resistance (or load). It is common to call the input force "the effort" and the output force "the load" or "the resistance." This allows the identification of three classes of levers by the relative locations of the fulcrum, the resistance and the effort: These cases are described by the mnemonic "fre 123" where the fulcrum is in the middle for the 1st class lever, the "r"esistance is in the middle for the 2nd class lever, and the effort is in the middle for the 3rd class lever. The lever is a movable bar that pivots on a fulcrum attached to
Lever tumbler lock of the lever lock which was designed to detect and prevent picking attempts. Lever locks can be drilled, but usually a template or stencil is required to mark the drilling point, as the lock mechanism is commonly mortised into the door and so it is harder to determine the point at which to drill. Lever tumbler lock A lever tumbler lock is a type of lock that uses a set of levers to prevent the bolt from moving in the lock. In the simplest of these, lifting the tumbler above a certain height will allow the bolt to slide past.