hall doors dumb waiters and similar lift mechanisms and other applications a door lock and switch comprises a fixed contact member that is attached to a movable door and a movable locking mechanism attached to a door jamb or second moving door the locking mechanism may comprise an involute gear and star wheel a pawl constrained by a torsion spring and an electromechanical means of actuating same application_number US 69454510 A description for purposes of illustration the electrical components that are associated with this device are not shown in detail the device is incorporated into known lifting devices and is connected to a power source signaling devices and switching devices as used with lifting devices turning to the drawing figures in a preferred embodiment gear 2 is supported on the housing back plate 8 and is rotatable about a stationary vertical pin 11 which acts as an axle fig2 a and 2b the gear is constrained in the u2018 locked u2019 position by spring biasing which may be provided by a torsion spring 4 the gear 2 may be constructed from a variety of materials and in one embodiment is formed of a hard resilient material such as acetal the gear as shown has a central bore that receives pin 11 allowing the gear to rotate about the pin the gear may be of a daisy.