Patent GB-1465325-A (GB)
Title: Electrical drive transmission for two working machine shafts
IPC: H02P5/50
Filed: 1974-05-22
Abstract: 1465325 Clutch control; electromagnetic control of brakes QUICK-ROTAN BECKER & NOTZ KG 22 May 1974 [23 May 1973] 22985/74 Headings F2L and F2E [Also in Divisions G3 and H2] The shaft 10 of a motor is coupled to output shafts 19, 19<SP>1</SP> through identical electromagnetic clutch-brake combinations 13, 35, the clutch coils 29, 29<SP>1</SP> of which, controlling the coupling of the shafts through clutch plates 22, are controlled by electronic circuitry which incorporates a speed ratio control system for maintaining the speeds of the output shafts at a predetermined ratio. A regulator (Fig. 3, not shown) is provided for each clutch-brake combination, each regulator incorporating a transistor switching stage for the clutch coil and a transistor switching stage for the brake coil, speed measuring devices 32, 33 and 32<SP>1</SP>, 33<SP>1</SP> providing inputs to the regulators, which inputs are rectified by full-wave rectifiers. A proportion of the output voltage from each full-wave rectifier is tapped from a potentiometer and supplied to a speed ratio control circuit, shown in Fig. 6. The output from one potentiometer is applied at 70, inverted in an operational amplifier 71 and summed with the output from the other potentiometer, applied at 73, so that the sum passes through an amplifier 72. When this sum is zero the output shafts 19, 19<SP>1</SP> have their speeds in the desired ratio, otherwise the output from the amplifier 72 acts on one clutch or brake coil (via the associated regulator) through an inverting amplifier 76 and output 74 and on the other coils from output 75 without inversion, this operating the clutch and brake coils to bring the output from amplifier 72 back to zero. The desired ratio is set by the potentiometers, which, at different settings require a certain ratio of the outputs from the speed measuring devices 32, 33 and 32<SP>1</SP>, 33<SP>1</SP> to attain the zero sum at the input of amplifier 72. A switching stage equipped with transistors 77  and 78 is provided for switching off the speed ratio control circuit. In addition to this ratio control, electronic circuitry is provided so that both output shafts can be slowed to a slow speed and then stopped in a predetermined position. The circuitry is shown diagrammatically in Fig. 2 wherein, in addition to the regulators 41, 44 and the speed ratio control circuit 53 a positional pickup 51 (comprising a Hall generator) is provided, a function insertion stage 49 (comprising logic circuitry), a coupling stage 50, and a nominal value transmission stage 48 for ordering regulators 41, 44 to run the output shafts at preset speeds of revolution. The stage 50 can cause such control as the stopping of an output shaft or the reduction of the speeds of revolution of output shafts 19, 19<SP>1</SP>. A key 82 is provided for changing over from a first to a second predetermined position, closing this switch in one such position causing slow rotation to the next position, where the shafts stop if the key 82 has been released. The drive may be used in industrial sewing machines. The clutch/ brake combinations of Fig. 1 have cooling fans 39, 391 incorporated in flywheels 11, 11<SP>1</SP>, a further fan 38 being provided for the motor.