GB928826A - Variable speed control device - Google Patents

Abstract

928,826. Variable speed gear and control; clutch control. O. KRUMMEL. March 10, 1961 [March 21, 1960], No. 8784/61. Class 80 (2). A continuously variable speed gear comprises a massive clutch driving member 4 intermittently axially displaced to engage a clutch driven member 5 by an electromagnet 3 controlled by a microswitch 9 by an electromagnet 3 controlled by a microswitch 9 actuated by a variable centrifugal governor to provide a substantially constant predetermined output speed. As shown, the member 4 is an armature journalled in rotatable pole members 3, 5 respectively fast on an input electric motor shaft 2 and an output shaft 5c. A variable centrifugal governor 8, output shaft driven through gears 6, 7, energizes and de-energizes, through a blade 9c and contacts 9b, 9a of the microswitch 9 and slip rings, respectively, the windings of the pole members 5, 3 when the output speed falls below a predetermined level, and vice versa. For starting, assuming the motor to be running, and the output shaft stationary so that the blade 9c engages the contact 9b and the pole member 5 attracts the member 4, a manual switch 11 is closed, whereby the winding of the pole member 3 is energized for a short period sufficient to rotate the member 4 and hence the pole member 5 and the output shaft until the latter reaches the desired speed, whereupon the governor actuates the microswitch to energize the winding of the pole member 3 independently of the switch 11 which can now be opened, and to de-energize the winding of the pole member 5. In Fig. 2 (not shown), the pole member 3 is dispensed with, the member 4 being splined of the input shaft and spring-urged to disengage from the driven shaft pole member.