GB848294A - Electrical snap-switches - Google Patents

Abstract

848,294. Snap-action switches; press-button retractive switches. SCHRACK, E. Nov. 19 1958 [Nov. 19, 1957], No. 37280/58. Class 38 (5). A switch comprises a main snap mechanism A working in conjunction with an auxiliary snap mechanism B adjustable to provide the switch with either one or two stable positions. Mechanism A is formed by a tip-lever 5 controlled by a spring 7 and pivoted at one end on a forked bracket, the other end carrying a bifurcated contact 6 movable between normally-fixed contacts 3, 3<SP>1</SP>, adjustable in terminal blocks 2, 2<SP>1</SP>. The spring- end 7<SP>1</SP> engages the thread of a longitudinallyfixed bolt 8, so that rotation of the latter moves the end 7<SP>1</SP> laterally to vary the contact pressures between contacts 6 and the respective contacts 3, 3<SP>1</SP>. Mechanism B comprises a pivoted tiplever 9 controlled by a spring 10, whose end 10<SP>11</SP> is laterally adjustable by rotation of a longitudinally-fixed bolt 11 and whose lower half is enclosed by a rigid sleeve 12 engageable by push-rods 13, 14. Depression of the rod 13 moves lever 9 anti-clockwise to strike the left side of the bifurcated contact 6 and so move mechanism A past dead-centre, whereupon both mechanisms act together to complete the switch operation, which can then be reversed by depression of the rod 14. If desired the spring-end 1011 may be moved to the right to prevent mechanism B from passing dead-centre during the switch operation, which in this case is reversed by the removal of pressure from the rod 13.