GB1160140A - Improvements relating to Rotary Switches - Google Patents

Abstract

1,160,140. Rotary switches. D. H. BONNELLA & SON. Ltd. 12 Dec., 1967 [14 Dec., 1966], No. 56027/66. Heading H1N. An automobile ignition switch has a rotary selector drum 4 having a plunger 5 co-operable with notches in a housing 1 to define accessory (Fig. 1), off (Fig. 2) ignition (Fig. 3) and start (Fig. 4) positions. Drum 4 has an integral pawl 6 and is made of resilient plastics so that the pawl is resiliently biased against a slider 3 received in a housing recess 2. The pawl may alternatively be a separate arm linked to the drum and biased by a spring (Fig. 7). During rotation from the accessory to off position (Figs. 1-2), pawl 6 pushes slider 3 to a first end of recess 2 and then moves along the inner face of the slider. During movement to the ignition position (Figs. 2-3) the pawl moves to the end of the slider, and during movement to the start position (Fig. 3-4) the pawl leaves the slider and rides along the housing. During reverse movement back to the ignition position (Figs. 4-5), the pawl rides along the housing till it engages the slider and pushes it away from the first end of recess 2. The end of the pawl now springs down into a gap between the recess and slider, Fig. 5, thus preventing return to the start position (Fig. 4) without first reaching the " off " position (Fig. 6), during which movement (Figs. 5-6) the pawl pushes the slider to the second end of the recess and then rides back on to the slider inner face.