GB490610A - - Google Patents

Abstract

490,610. Electromagnetic switches. ROBERTSON, G., and ROCHER, E. J. Feb. 20,1937, No. 5168. [Class 38 (v)] [Also in Groups XXVII and XXXV] A battery isolating switch which opens automatically after a time interval commencing with the stoppage of an internalcombustion engine is held closed both by generator current and by a pressure change consequent on the running of the engine. Contacts 3, 4 are spanned by a laminated bridge 5 mounted on a stem 6 to which is secured a sleeve 12 of magnetic material and a diaphragm 17. A coil 9 surrounds the sleeve 12, and the diaphragm is clamped at the rim forming compartments 21, 23, the space 21 being open to the atmosphere and the space 23 to engine suction by way of a pipe 24, with a ball-valve 26 to prevent damage due to back-firing. An adjustable needle-valve 31 forms a leak to or from the chamber 23 whereby a time-lag occurs after engine stoppage before the bridge 5 is moved to open the switch. The ordinary starting-switch 1 has an additional contact 35. Battery current traverses contacts 35, 36 and energizes coil 9. Contacts 3, 4, 5 close and current is directed to ignition, lighting and other accessory circuits by way of the contact T. Further movement of the switch D closes the circuit across contacts 36, 37 and the starter S is energized. As the output of the generator G increases the electromagnetic switches C<1>, C<2> are closed, and keep energized the coil 9 after the switch D has been opened.