GB1422006A - Rotary switching assemblies - Google Patents

Abstract

1422006 Variable resistors; mechanical switches MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 2 April 1973 [4 April 1972 (3) 6 Nov 1972] 15732/73 Headings HIS and H1N [Also in Division H3] A switch assembly comprises a push-pull switch 24, operated by axial movement of a shaft 1, and a rotary variable resistor 47 and a further switch 52 which are operated by rotation of the shaft 1, a device 35 being provided to ensure that switch 52 cannot be open unless switch 24 is in its open position. Upon pulling shaft 1 an insulating member 9 is urged by U-shaped springs 15 so that contacts 13 on a contact member 11 are engaged with a snapaction with respective contacts 20 of switch terminals (18, Fig. 6, not shown). Similarly contacts (14) of switch 24 are electrically connected to further terminals (19). Rotation of the shaft 1 rotates the wiper 46 of the rotary resistor 47, this rotation being limited by a projection 34 or a stop member 33 engaging a side surface of a projection 32 on a fixed insulating base 28. Upon pushing of the shaft 1, the connections in switch 24 are broken and projection 34 is moved clear of projection 32 so that further rotation of the shaft is possible and a projection 50 on the wiper holder 45 can depress an actuator 49 to open switch 52. When this switch is open, shaft 1 cannot be moved axially due to projection 34 engaging the top surface of projection 32. To assist relative axial displacement of the projections 32 and 34, they may be provided with sloping surfaces (32a, 34a, Figs. 10, 11, not shown). A support 25, a plate 27, the base 28 and a cover 29 of the device 35 may be replaced by an integral connecting member (101, Fig. 13, not shown). In a second embodiment (not shown) the switch 52 may only be opened when the shaft 1 is pulled. The switch may be used in the preheater circuit (Fig. 1, not shown) of a television receiver.