| 摘要 |
<p>1,059,765. Automatic speed control. C.A.V. Ltd. March 4, 1965 [March 19, 1964], No.11616/64. Heading G3R. A pump 11 to be tested is driven by electric motor 10 through variable speed transmission 12 comprising a pair of pulleys associated with a driving belt, each pulley being divided and the relative axial setting of the parts being controlled by piston-cylinder actuators. When fluid under pressure is supplied to one actuator, the effective diameter of the associated pulley is increased and the diameter of the other pulley is decreased. When carrier 36a is set at an angular position equivalent to the required speed of operation of the pump, photo-cells 33b, 34b, 35b, are illuminated so that relays are operated to energize valve-solenoids 22, 23, 25, whereby the transmission mechanism is set to accelerate the pump. As the speed increases, mask 39, associated with tachometer generator 40 obscures cell 33b so that solenoid 25 is de-energized to reduce the rate of acceleration. Eventually, the mask obscures cell 35b and solenoids 22, 23, are de-energized for preventing further change of speed. To reduce the speed, the carrier is moved in the opposite direction, and cell 34b is obscured, thereby causing solenoids 22, 26 to be energized. A substantial reduction of speed is afforded by uncovering cell 35b to effect deceleration at a high rate. Subsequently, cell 35b is obscured to reduce the rate of deceleration, and finally cell 34b is illuminated to prevent further variation of speed. If the speed of the pump alters when the solenoids are de-energized, the mask move in the appropriate direction to restore the speed to the value determined by the setting of the carrier. The carrier has its setting varied in accordance with a predetermined programme by means of disc 41 having two series of holes 42, 43, for increasing and decreasing the pump-speed respectively, the holes being arranged in accordance with the desired speed programme. The disc is driven by motor 46 through a slipping belt coupling in either direction, the holes co-operating with electro-magnetically operated stops 44, 45.</p> |
