GB142494A - Improvements in or relating to electric switches - Google Patents

Abstract

142,494. Gallo, G., and Villarboito, F. April 29, 1919, [Convention date]. Switches, quickaction.-Relates to push-button-operated switches in which a contact - piece carried by a stem moving longitudinally reaches the end of its stroke in the contact position at the first actuation and release, and, on a second actuation and release is held spaced apart f r o m the contact position by a cam which t a k e s up different positions in the two movements. According to the invention, the cam is of lenticular shape and is rotated into the locking and unlocking positions by a recess and a stop at each end of the opening in which the cam moves, the recess and the stop being oppositely disposed at the two ends. As shown in Fig. 2, the spring-retracted plunger 6 has an enlarged head 5 moving within the frame 1 and carrying a contact-roller 5' to engage the fixed contacts, and a pivoted lenticular cam 9. In the position shown, the plunger is held in the non-contact position by the cam engaging the stop 11. When the plunger is pushed, the cam is caused to rotated by reason of the engagement of a spring 14 with its left-hand end, and the rotation is continued by engagement with the edge of recess 12 until the position shown in dotted lines is reached. On release of the plunger, the contact-roller is free to engage with the fixed contact, the cam taking up the dotted line position shown in Fig. 3. On a second actuation of the plunger, the left-hand point of the cam engages with the stop 13 and is brought round into the transverse position in which, on release of the plunger, it prevents the contact roller from reaching the fixed contact.