GB1205273A - Servo control - Google Patents

Abstract

1,205,273. Electric positional control systems. AMERICAN MACHINE AND FOUNDRY CO. Feb.16, 1968 [March 27, 1967], No.7696/68. Heading G1N. Apparatus for sequentially positioning a member to a plurality of discrete positions comprises an automatically rebalanced bridge network with selectable pre set potentiometer transmitters 108- 124 operating through differential amplifier 112 and drive means 128 to position the member and rebalance the network by adjusting a common receiver potentiometer 130. Selection is effected by a cam element 134 driven by clock drive 136. For the first position, determined by the slide of potentiometer 108, switch 12 is closed by cam element 134 to energize relay 26 which connects potentiometer 108 to amplifier 112, and the drive means 128 positions the controlled member accordingly. Closing switch 12 also energizes relay 18 and charges capacitor 20. Contacts 22, 24 open, until the charging current falls to below energization level for relay 18, and then reclose. This completes a holding circuit for relay 26 through diode 36 and contacts 28, 30 so that switch 12 may be opened, but the drive means 128 continues to operate. Subsequent rotation of cam 134 closes switch 38 and repeats the above procedure, initially breaking the holding circuit for the previous relay 26 when relay 18 is first energized and contacts 22, 24 are opened. The controlled member is thus sequentially positioned in accordance with the settings of potentiometer 108-124. A homing position, set on potentiometer 124, is manually selectable by switch 126.