GB486116A - Improvements in or relating to snap action electric switches - Google Patents

Abstract

486,116. Electromagnetic interrupters; snap action switches; transformers. BURGESS LABORATORIES, Inc., C. F. Oct. 29, 1936, No. 29478. Convention date, Dec. 4, 1935. [Class 38 (v)] [Also in Group XXXV] An interrupter which may be used in an induction coil to give a series of flashes in a neon tube, say every two seconds, comprises an actuating member such as an armature 232 having a natural period of vibration and adapted to carry the end 248 of a compression spring 244 over dead-centres relatively to a tension strip 238 to which the spring 244 is connected at 242. In the form shown, the common ends of the members 244 and 238 carry a contact 246 which engages a contact 250 and closes the circuit to the primary 220 of the induction coil. The armature 232 is thus attracted, moves the point 248 downwards beyond the strip 238 so that this snaps upwards carrying the contact 246 away from the contact 250. This breaks the primary circuit and causes a flash in the neon tube energized by the secondary. The armature now returns to its original position and the contact snaps back into the closed position in a similar manner. Owing to the inertia of the armature, however, it goes beyond the original position and for a short time oscillates to and fro with decreasing amplitude during which time by engaging. the spring 244 which acts as a bumper, the contact 246 is periodically lifted off the contact 250. The dead-centre position is not passed during this oscillation and the frequency of break is such that no bright flash is produced in the neon tube, but, in some cases, a series of dim flashes which merge into a continuous glow. When the contacts 246, 250 engage each other long enough for a full energization of the magnet 220, the armature 232 is again attracted down to move the point 248 over the dead-centre position, with a snapping over of the contact 246 and a bright flash in the neon tube. Specification 419,917 is referred to. The Specification as open to inspection under Sect. 91 also describes a number of forms of snap-action switches all having the feature of a tension member 16, Fig. 1 (Cancelled), connected at one end 24 to a compression member 22 and the two other ends of the member being relatively movable so that the mounting point of the compression member crosses the line of the tension member to cause a quick action. The form shown in Fig. 1 (Cancelled) is operated thermally by a bimetallic strip 12. Fig. 3 (Cancelled) shows a form operated off and on by respective depression of two push-buttons 58, 62. Fig. 11 (Cancelled) shows a switch electromagnetically operated. This subjectmatter does not appear in the Specification as accepted.