Patent GB-512959-A (GB)
Title: Improvements in and connected with the electric circuits of motor vehicles
Filed: 1938-03-24
Abstract: 512,959. Supply systems for vehicle lamps. LACEY, E. G. March 24, 1938, Nos. 8997 and 8998. Convention dates, April 7, 1937, and Sept. 25, 1937. [Class 38 (iv)] [Also in Group XXVII] Manual means close the ignition circuit of an i.c. engine for a limited duration and oil pressure responsive means maintain the circuit closed during normal operation so that ignition is interrupted if the oil pressure responsive means do not operate within the said duration. Time delay means may however maintain the circuit for a short period afer the pressure responsive means have become inoperative. A switch controlling ignition and load circuits 47, 49 of an i.c. engine in accordance with engine running comprises contacts 27, 26 on spring leaves 19, 24 in the circuit from a battery 17 and generator cut-out 58 The upper contact is normally held off by a stretched wire 13 but is provided with an auxiliary contact 54 which permits energisation of parking lamps 52. When a push button 16 is closed to energise a starter motor 18, the wire 13 is connected across the battery and after an interval, sags so that contacts 27, 26 close. When the engine comes up to speed, pressure of lubricating oil causes the leaf 24 to be raised by a diaphragm operated push rod 42 so as to hold the contacts 26, 27 closed as long as the engine is running and oil pressure is correct. Failure of oil pressure for any reason causes leaf 24 to drop but the contacts are still held closed by the leaf 24 abutting against a bimetallic stop member 30. A conducting cap 31 on the stop member completes circuit with the leaf 24 for a heating winding 33 which, after a time interval, causes flexure of the strip 30 beyond a shoulder 29 so that the leaf 24 then drops still further, opening the contacts, 26, 27 and breaking the ignition &c. circuits. The leaf 24 may be raised and held raised by a hand operated member 39 which raises a push rod in a stop 35. During engine running contact 54 is raised and the parking lights 52 are switched off whilst headlights 49 are on. The horn and wireless set circuits 56, 57 may also be controlled by the switch 26, 27. Where required, any equipment such as a lamp 59 may be connected directly to the battery. In a modification (Fig. 9 not shown), the cut-out 58 is connected to the battery only through an auxiliary leaf and contact arranged below the leaf 24 so as to make the circuit and raise the leaf 24 only when the oil pressure is sufficient The auxiliary leaf is normally earthed on the stop 35 and is not delayed in its return so that damage to the generator and load circuits is avoided by cutting off the generator and disconnection from the battery as soon as the oil pressure falls. In a modification, Fig. 10, closure of switch 16 causes energization of the starting circuits and also of a relay 78 which operates a leaf. 19 to close the load circuits and its own holding circuit. The core of the electromagnet 78 is of material which decreases in permeability as its temperature increases. The winding of the relay incorporates resistance so that this relay releases a predetermined time after energization. The load circuits are held closed during engine running by oil pressure responsive means 42 and when the engine stalls the circuits are held closed for a predetermined time by the bimetal stop 33. The Specification as open to inspection under Sect. 91 describes a modification, Fig. 10 (Cancelled), in which closure of the switch 16 causes energisation of a coil 69 of an electromagnet 68 to draw down the leaf 19 and close the load circuits. When the engine comes up to speed the voltage of its generator energises a coil 70 on the relay 68 to hold the contacts closed. If the engine stalls the contacts are held closed by the bimetal stop 74 the heater of which is energised so that the contacts are allowed to open a predetermined time after stalling. The winding 70 may be omitted and oil pressure responsive means as above described provided. This subject-matter does not appear in the Specification as accepted.