GB442969A - Improvements in and relating to cam-driven electric switches - Google Patents

Abstract

442,969. Snap-action switches. BRITISH THOMSON - HOUSTON CO., Ltd., Crown House, Aldwych, London. Jan. 15, 1935, No. 1365. Convention date, Jan. 16, 1934. [Class 38 (v)] In a quick-action switch operated by a cam drum 2, the drum acts on the arms 13, 14 of a lever 1 pivoted at 3, the lever 1 having two other arms 15 which embrace a spring 16 arranged between the two arms of a contact lever 4 also pivoted at 3. As shown in Fig. 2, the spring 16 also bears on projections 5 on the arms of the lever 4. When the cam drum is rotated in a counter-clockwise direction, the lever 1 is moved into its dotted position and its upper arm 15 compresses the spring 16 which tends to force the lever 4 into the open position, but this movement is prevented by the engagement of rollers 21, 20 on the arm 4 and a latch 7 until a projection 9 on the lever 1 engages a projection 10 on the latch. In the open position, the roller 21 bears on the opposite side of the roller 20, which prevents movement of the contact arm 4 to close the switch when the cam is rotated in the reverse direction until a projection 11 on the arm 1 engages the end 12 of the pawl. In the event of the contacts sticking, positive actuation is effected by a lug 16 on the lever 1.