GB836018A - Improvements in or relating to electric switch arrangements for protecting plant against unauthorised use - Google Patents

Abstract

836,018. Switches held set and freed mechanically. SCHNEIDER, H., and MATTES, C. July 16, 1956 [July 19, 1955], No. 21913/56. Class 38 (5). A switch arrangement intended to prevent unauthorized use of motor vehicles or other plant, comprises a casing 21 which is countersunk flush with a wall of the object to be protected and has a space 22 receiving a removable part 10. The casing has an annular disc 23 carrying a lug 39 which co-operates with abutment stops 38 on the casing to limit rotation of the disc 23 to 90 degrees, and the disc also has shaped openings 24 which co-operate with corresponding formations 11 on the part 10 to ensure correct insertion of the latter. The space 22 is closed by surfaces 25, 29 having a pair of shaped openings 26, 30 at right angles to one another to receive a corresponding formation 20 on the bottom of part 10, the arrangement being that the formation 20 has first to be passed through the opening 26 and the part 10 then turned through 90 degrees to pass the opening 30. During turning, the part 20 rotates a disc 27 having a similar aperture 28 so as to move a contact 35 out of reach of a spring plunger contact arrangement 37 which is located so as to be depressed if an attempt is made to open a door when the device is immobilized. When fully inserted the part 20 closes contacts 33 or 34. The part 10 contains a non- rotatable threaded bolt 13 to the head of which are pivoted a pair of conducting or insulating contact-actuating members 16, 17. When the part 10 is inserted, a screw handle 12 is unscrewed from the bolt 13 which is depressed by a spring 15 so as to project the members 16, 17 outwardly through slots 18 to engage contacts 31, 32 or either selectively. To immobilize the vehicle, the handle 12 is screwed on the bolt to withdraw members 16, 17 and the part 10 bodily withdrawn, so as to leave all operating circuits dead and an alarm circuit connected to the plunger switch 37 prepared for operation.