GB632649A - Improvements relating to manually operable selector levers, switches and the like - Google Patents

Abstract

632,649. Locking switches. McCLEMENTS, A. May 14, 1946, No. 14541. [Class 38 (v)] [Also in Groups XXIV and XXXIII] A selector switch, particularly for use in an aircraft undercarriage control system is so arranged that it can be locked against operation by a normal manual force during take-off, or released for operation when the aircraft reaches a predetermined airspeed, while in an emergency it can be operated, while looked, by the application of an abnormal manual effort. In the form shown in Fig. 2, the switch has two push-buttons 41, 42, the former being mounted on a spindle 43 extending into a compartment containing a solenoid 45 mounted on a pivot 46. The solenoid plunger 47 is urged outwardly by a compression spring 48, and in its extended position the end of the plunger 47 enters a recess in the spindle 43. A compression spring 49 holds the solenoid in its end positions. In the position shown, with the solenoid not energized, the spring 48 prevents normal operation of the switch; with the solenoid energized, however, the plunger 47 is retracted against the spring 48 to allow operation of the button 41. In an emergency, however, the force of the springs 48, 49 may be overcome by an abnormal force exerted on the button 41, to move the solenoid 45 over the dead-centre position. Specification 605,274, [Group XXXI], is referred to.