Patent GB-473315-A (GB)
Title: Improvements in or relating to engine starters
IPC: F02N15/08
Filed: 1936-08-18
Abstract: 473,315. Connecting and disconnecting arrangements for friction gearing. GENERAL MOTORS CORPORATION. Aug. 18, 1936, No. 22776. Convention date, Aug. 19, 1935. [Class 80 (i)] [Also in Group XXVII] In an electric starter, driving discs 122, 123 are brought into engagement with the opposite faces of a driven disc 120 independently of the operation of the starting motor, for example by an electromagnet' 75 and lever 70, whilst upon operation of the starting motor the driving discs are pressed against the driven disc with a pressure which is sufficient for driving engagement and is automatically relieved when the engine becomes self-operative. As shown, the driving disc 122 is formed on a sleeve 30 splined at 31 on the armature shaft 26 of the starting motor 20, and the disc 123 is the end face of a sleeve 50 supported on the sleeve 30. External threads 51 on the sleeve 50 are engaged by the flange 52 of a collar 53 having an external flange 54 engaged by studs 79 on the bifurcated end of the lever 70. The inner end of the sleeve 52 is formed with a pair of cams each comprising surfaces 60, 61 of different pitch and a projection 62 limiting movement of a roller 38, engaging the cam and carried by a yoke 34 on the end of the sleeve 30. The parts are normally maintained in the position shown in Fig. 2 by springs 42, 57 and by a spring 76 engaging the upper end of the lever 70, which has a slot 71 in engagement with a pin 72 carried on the electromagnet frame 75. The lever 70 is connected by a link 84 to the armature 82 of the electromagnet, which has a fine winding 80 of many turns connected to earth at 108 and a heavy winding 81 of few turns connected to earth through the motor 20. A switch 105 serves to connect the battery 101 to the ignition circuit at 103 and to the electromagnet at 104. The resulting movement of the lever 70 to the left effects the movement of the sleeve 50 and disc 123 to the right of the engagement of the flange 52 with the screwthreads 51 ; rotation of the sleeve 30 is prevented by extensions 64 of the collar 53 with the arms 35 of the yoke 34, owing to the inertia due to the mass of the shaft 26 and the parts rotatable with the shaft, and the movement of the sleeve 50 to the right is effected by the cam surfaces 60, 61 riding over the rollers 38 on the yoke 34. When the disc 123 comes into engagement with the disc 120, further movement of the lever 60 causes the sleeve 30 to bring the disc 122 into engagement with the disc 120. The circuit of the motor 20 is then closed at 96, 97 by a contact 95 on an extension 85 of the armature 82, cutting out the electromagnet winding 81, so that the winding 80 alone maintains the armature in its attracted position. The discs 122, 123 are then tightened by the interaction of the rollers 38 and cam surfaces 61 and transmit the drive. When the engine starts this engagement is released and the circuit of the motor 20 is broken at the contact 95, owing to the interruption of the circuit of the electromagnet winding 80 by a contact 114 attached to a diaphragm 113 acted upon by engine suction.