GB1052356A - - Google Patents

Abstract

1,052,356. Controllers; control of D.C. motors. CLARK EQUIPMENT CO. June 1, 1965 [June 1, 1964], No. 23326/65. Headings H2B and H2J. [Also in Division B7] A vehicle 10 (Fig. 1, not shown), has a motorspeed control or master accelerating switch 146 with an operating plunger 148 which is spring- biased outwards towards speed increase, the plunger 148 being allowed to move outwards by an accelerator comprising a hand lever 24 and associated mechanism (Fig. 3, not shown), and being pushed inwards to overridingly close down by release of a brake pedal 26 which brakes the vehicle (Fig. 1, not shown), actuation by the brake being independent of that by the accelerator so that braking does not affect the position of the accelerator, whereby the bias of the motor-speed control can effect automatic re-acceleration of the vehicle when the brake is subsequently released. The accelerator 24 actuates plunger 148 via mechanism 168 and a pin 182, with either forward or reverse drive, while the brake pedal 26 actuates plunger 148 via a rod 208, bell-crank 202 and arm 204. The control 146 includes switches 110, 128, 134 and 140 (Fig. 2, not shown), which are actuated in a particular sequence by movement of plunger 148 from its innermost position. With switch 140 closed, closing of switch 110 energizes relay coil 122 or 124, depending upon the position of switch 114, to actuate forward switch 82 or reverse switch 76 so that current flows through field windings 46, 48, of the drive motor to provide forward or reverse operation of the motor. Closing of switch 128, and opening of switch 140, energizes relay coil 130 to close switch 54 and place resistances 56 and 52 in parallel, thus halving the total resistance between conductor 34 and motor armature 40 to increase the drive motor speed. Then closing of switch 134 energizes relay coil 136 to close switch 58 to by-pass resistances 56, 52, and further increase the motor speed. Finally, switch 140 recloses to energize relay coils 143, 144, and actuate switches 90, 100 to re-connect the field windings in parallel. Application of the brake opens a switch 42 in the power circuit. There is also a keyoperated switch 22 in the power circuit.