GB1092535A - Piezo electric ignition devices - Google Patents

Abstract

1,092,535. Piezo electric generators. EVERED & CO. Ltd. Aug. 20, 1965 [May 21, 1964], No. 20959/64. Heading H2A. [Also in Division F4] A piezo-electric igniter comprises a casing 10 containing within an insulating sleeve 13 an H.T. conductor 12 connected to a steel anvil 14 which is in contact with the piezo-electric element 18 via a conducting aluminium pressure pad 17a; a striker 21 is adapted to deliver a blow to the element 18 via a hardened steel pressure plug 19 and a second conducting pressure pad 17b after said striker has been automatically released upon being loaded to an extent sufficient to obtain said energy. The striker, of cylindrical shape, is loaded against the action of a spring 23 by a pin 27 provided with a ball catch 29 housed in a blind radial bore 30, which engages in an annular recess 26 in the interior surface of the striker. When the striker spring is compressed to a predetermined extent its end abuts the bush 11b which serves as a stop member, and an extra pull on the pin 27 causes the catch 29 to be released and the striker to give a sharp blow to the element 18. The aluminium members being resilient adapt themselves to the shape of the end faces of the element and distribute the force applied by the striker uniformly. An earth return is provided to the end of the element 18 remote from the H.T. conductor 12 by the casing 10. The pin 27 is provided with a reset spring 32. In the embodiment of Fig. 3 (not shown), two piezoelectric elements 118 are separated by a pressure pad 117c which is connected to the H.T. conductor 112 by a screw 134. The extreme ends of the elements 118 are electrically connected to the casing 110 so that electrically the elements are connected in parallel. In the embodiment of Fig. 4 (not shown), the striker 221 is withdrawn against the action of a spring 223, by a pot magnet 235, and is released either when the attraction of the magnet is overcome by the loading of the spring or when the spring is fully compressed so as to become " solid " against a collar 245.