| 摘要 |
920,680. Controllers; control of D.C. motors. RANSOMES SIMS & JEFFERIES Ltd. Oct. 27, 1961, No. 38485/61. Class 38 (3). The battery powered traction motor of a fork lift truck is controlled in both speed and direction by a single pedal 25. This has a tiltable plate 45 biased to one side to give forward movement ; pressure on the other side against the bias operates a microswitch 57 for reverse. Acceleration is effected by normal depression of the whole pedal, which motion is transmitted hydraulically to a push-rod 73 which, as shown, is connected to a master drum controller 87. The motor is series wound, reversal is effected by changing the field connections and four speeds are obtained by first inserting two series resistors, then short circuiting one, next connecting them in parallel with each other and finally short circuiting both. An interlock switch prevents energization of the motor until the vehicle brakes have been released. It is stated that alternatively the push rod 73 could operate a carbon pile resistor, insert diverter resistors across the motor field, or operate an electronic voltage or current controlling device in the motor circuit. |
