GB729401A - Improvements in or relating to electric control apparatus for multi-speed transmission gears - Google Patents

Abstract

729,401. Controlling change-speed gearing. BOSCH GES., R. Aug. 11, 1953 [Aug. 13, 1952], No. 22080/63. Addition to 727,757. Class 80 (2). [Also in Group XXXVII] A modification of the electric switching apparatus described in Specification 727,757 relates to the control of a reversible electric motor 10 having oppositely-wound field windings 11, 12 and driving a control shaft for actuating the gear-changing mechanism of a vehicle. The control gear for the motor comprises an electromagnetic switch 14, an impulse switch 15, and a switching device 16 having cams 25, 26, driven by the control shaft. In order to change from the neutral position shown into first gear, the switch 74 is momentarily engaged with contact 73, the contact 44 being closed when the driver occupies his seat. A coil 69 of the switch 15 is thus energized to close contacts 76, 63, and current passes from battery 18 through holdcoil 71 and operating winding 22 of switch 14. Energization of the motor 10 through its field winding 12 follows, and the cams 25, 26 are driven in a clockwise direction. After movement through a predetermined angle, a camoperated switch 36 is closed so that current flows directly to the winding 22 and the hold-coil 71 is short-circuited (with normal operation), the springs 65 returning the switch 15 to its neutral position. Rotation of the cam 25, 26, through a further angle causes a projection 46 to open switch 53 for a short period so interrupting the circuit of coil 71 and opening switch 15 in the event of imperfect short-circuiting due to soiling of the contacts of switch 36. The switch 14 remains closed until projection 29 opens switch 36 to disconnect winding 22 and stop the motor in the position of engagement of the first gear. A change without interruption to the sixth gear may be effected by continuous engagement of the contact 73, and, when the last gear is reached, the switch 53 is opened by projection 51 to prevent further rotation in the clockwise direction. Changing down to a lower gear is effected by engaging switch 74 with contact 72, the joint use of a switch 79 being necessary for changing from neutral to reverse gear. A motor-driven arm 77 is used to light signal lamps for indicating the engagement of the various gears.