Patent GB-1102694-A (GB)
Title: Improvements in or relating to electromechanical rotary drive systems
IPC: H02P8/14
Filed: 1964-04-24
Abstract: 1,102,694. Selective signalling. BRITISH UNITED SHOE MACHINERY CO. Ltd. (United Shoe Machinery Corporation). 23 April, 1965 [24 April, 1964], No. 17010/64. Heading G4H. [Also in Division H2] A slow speed driving device employs epicyclic strain gearing which comprises a flexible tube output member which is deflected into operative engagement with a fixed reaction ring successively at points around its periphery by the armature of an integral electromagnetic device. The flexible tube may be toothed and engage with similar teeth on the reaction ring or frictional engagement may be used. As shown, a fixed housing carries annular reaction ring 20 and stator 34 which consists of a number of U-shaped wound poles spaced around the periphery of the armature 32 and energized in sequence from an electronic supply circuit, Fig. 6 (not shown). A flexible tube 28 is mounted on shaft 10 and has teeth 30 on its outer periphery for engagement with teeth 26 on ring 20 when it is deflected into an elliptical shape. Armature 32, which may rotate with the output member or in a modification is freely rotatable or fixed, comprises an annular series of laminations which are supported on ring 40 but are free to pivot radially under the influence of the stator field when the resilience of bonds 50 is overcome. In operation diametrically opposite stator poles are energized to draw the corresponding laminations of the armature towards the respective pole faces 56, 58, thereby deflecting the flexible tube into an elliptical shape with the outer periphery along the major axis in contact with reaction ring 20. When the adjacent pair of diametrically opposed stator poles are energized then the major axis of the tube is rotated to produce relative motion between the tube and ring and hence rotation of shaft 10. The device may be modified by making the stator annular and winding it with a polyphase winding to produce a rotating magnetic field when energized. In this construction the armature can be either similar to a clock spring, or be an endless chain lying inside the flexible tube to deflect it into elliptical shape under the influence of the magnetic field. Alternatively the armature may comprise a slotted core with iron powder enclosed between the core and tube so that the powder builds up on the periphery of the core under the influence of the magnetic field to deflect the tube. The tube may be of metal or plastics material with embedded strengthening wires. The sequential energization of the stator coils is controlled by the circuit of Fig. 6 (not shown), where a voltage level determines the output frequency of a pulse generator and the polarity of the input determines the output wire on which the pulses appear. The pulses are passed to a number of counters in series whose outputs are fed to AND gates which control a flip-flop stage which in turn controls the power supply to the diametrically opposite coils of the motor stator. To provide that more than one pair of coils is energized at the same time and thus give smoother operation, the flip-flop is also controlled through an OR-gate to be switched off when a later pair of coils in the sequence is energized. The input line on which the pulses appear controls the order of energization and hence the direction of rotation of the output shaft.