GB344103A - Improvements in or relating to apparatus for delivering electric impulses from a source of current supply - Google Patents

Abstract

344,103. Inertia make and - break switches; retractive switches. THEW, W., 14, Upper Wimpole Street, London. Dec. 18, 1929, No. 38785. [Class 38 (v).] A device for producing a series of current impulses which may be employed for example in conjunction with a dental or surgical chisel of the type described in Specification 316,478, [Class 124, Stone &c.], comprises a hinged casing B adapted to be depressed by the foot to bring the contacts K<4> into engagement with the inclined end of a relatively fixed contact blade K. The movement of the casing sets in vibration a loaded contact blade F fixed at one end beneath a block E and carrying a weight F<1> at its other end and thus a series of current interruptions are produced between a contact G on the blade and a contact block G<1> fixed within the casing the contacts G, G<1> being in series with contacts K, K<4>. In the return movement of the casing after release by the foot the current impulses in the controlled circuit occur as this circuit is broken, at contacts K, K4. In an alternative form of switch the contact on the vibratory member is below and normally out of engagement with the fixed contact G1. In this form a single current impulse may be produced by first inverting the switch and then bringing contacts K, K<4> in together. The period of oscillation may be varied by the provision of an adjustable weight which may be renewed at varying positions along the spring F.