Patent GB-1442590-A (GB)
Title: Electric switches
IPC: H01H13/02
Filed: 1973-07-04
Abstract: 1442590 Mechanical switches; retractive switches ILLINOIS TOOL WORKS Inc 4 July 1973 [7 Dec 1972] 06510/76 Heading H1N A switch comprises a pawl 84 which thrusts against a pivotally mounted oscillator 98 to cause operation of the switch, pawl 84 being mounted on a torsion bar on a carrier 58, pawl 84 being deflected as it thrusts against oscillator 98 but the torsion bar being simultaneously deformed around its longitudinal' axis to allow pawl 84 to remain undeformed. The switch may be set by a selection lever 112 so that it acts with a snap action or a retractive action. Lever 112 cooperates with oscillator 98. Carrier 58 is of plastics material and has two slots 90, Fig. 3 (not shown) in its top surface, the pieces of top surface 86, Figs. 3, 4 (not shown) between slots 90 acting as the torsion bar by virtue of its resilience. Carrier 58 is depressed by pushbutton 28 against the action of return springs 54, 56 which also act as electrical connections between terminals 24, 26 and lamp contacts 50, 52 so that lamp 44 is alight continuously when terminals 24, 26 are energized. Selection lever 112 is pivoted about a pin 114, integral with lever 112 and which rests in a recess 116 for snap action, Fig. 6, or a recess 118 for retractive action, Fig. 8, the other end of lever 112 being urged by spring 124 so that nose 130 on the top surface of lever 112 engages either notch 132 or 134 as appropriate, see below, in oscillator 98. Recesses 116 and 118 are formed in the base 6 of the switch and lever 112 can be moved from one to the other by inserting a tool through opening 126 in base 6 into blind hole 128 in lever 112. Assume the switch is arranged for snap action, then pin 114 is in recess 116. When pushbutton 28 is depressed, pawl 84 engages between shoulders 98, 106 on oscillator 98 rotating it anticlockwise about axis 100 and nose 130 which initially was in notch 132 is depressed out of notch 132 stressing spring 124 till nose 130 passes over point 140 between notches 132, 134 and spring 124 is released and forces nose 130 into notch 134 with a snap action rotating oscillator 98 with a snap action so that cam surface 110 on oscillator 98 depresses blade 22 with a snap action changing over the movable contact from fixed contact 18 to fixed contact  20. When pushbutton 28 is released and pawl 84 rises, oscillator 98 and the contacts remain in that position until pushbutton 28 is again depressed, so that pawl 84 engages between shoulders 104, 108 on oscillator 98 pivoting it clockwise and forcing nose 130 from notch 134 to notch 132 with a snap action changing the fixed contact back to contact 18. Assume the switch is arranged for retractive action, then pin 114 is in recess 118. Nose 130 then engages notch 134 and when pawl 84 is pushed down it engages between shoulders 98, 106 and urges oscillator 98 anti-clockwise which compresses spring 124 while cam surface 110 urges blade 22 down to change over the contacts, but when push-button 28 is released and pawl 84 rises, spring 124 extends again and pushes lever 112 and oscillator 98 back again so that cam surface 110 pivots clockwise allowing blade 22 to rise and change back the contacts. The switch is double pole.