GB610633A - Improvements in automatically and electrically operated change speed gear - Google Patents

Abstract

610,633. Controlling change speed gear. AUSTIN MOTOR CO., Ltd., and HIGHFIELD, F. W. W. April 12, 1946, No. 11246. [Class 80 (ii)] In an automatically and electrically operated change speed gear in which constant mesh gears are engaged with their shafts by electromagnetic clutches, two generators having voltages proportional to their speeds, are driven from the driving' and driven shafts respectively and relays are provided which pull in at voltages proportional to the speed of the driven shaft and are excited by current from that shaft, the relay for the first speed being arranged to be excited by current from the driving shaft generator. The manual lever 11 is moved to contact the post 1 to engage first speed by allowing current to flow from the engine-driven generator 8 through lead 30, potentiometer 29, the closed switch 16 of the relay 12 and the first speed clutch coil 1a. As the vehicle speeds up, the generator 5 on the gear-box driven shaft supplies current to the relay coil 12 through the potentiometer 31, this relay pulls in at a given rise of voltage and thereby closes the switches 14, 15 and opens the switch 16, so allowing current from the generator 5 to flow through the coil of relay 17 and current from the battery B to energize the clutch coil 2a of the second speed, the coil 1a being switched out. The switch 13 opens and closes during the change to momentarily cut out the ignition. As the vehicle speed increases, a similar function is performed by the relays 17, 22 operating to energize the coils 3a, 4a. On reduction of speed, the voltage of the generator 5 drops and successively becomes insufficient to hold the relays 22, 17, 12 in, with the result that the coils 4a, 3a, 2a are de-energized. These changes are effected automatically so long as the changeover switch 28 is in the automatic position, and the switch 11 is on the post 1; if the switch 28 is in the manual position, gears, including reverse R may be engaged manually. The potentiometer 26 is coupled to the pedal doing duty as a clutch pedal and enables the voltage in the energized clutch coil to be reduced to free the engine. The potentiometers 29, 31 are connected to the throttle pedal to prevent hunting when moving from rest or when changing down. The gear may be used in conjunction with a fluid coupling or an eddy current clutch, and according to the Provisional Specification the generators may be alternators feeding through rectifiers.