GB496568A - Improvements in or relating to power driven electric-circuit changing mechanism - Google Patents

Abstract

496,568. Actuation of switches. BRITISH TABULATING MACHINE CO., Ltd. May 31, 1937, No. 15110. Convention date, June 1, 1936. [Class 38 (v)] A mechanism for automatically effecting the shifting of circuit connections comprises a driving member moving with intermittent circular motion, this member being driven from a continuously rotating shaft through a drive mechanism which effects a predetermined number of steps of intermittent motion for a complete rotation of the operating shaft, a rotatable brush member co-operating with a stationary commutator, a clutch for clutching the brush member to the driving member and a clutchcontrol mechanism for effecting clutching and unclutching to cause step-bystep rotation of the brush member when required. As shown in Fig. 1, a continuouslydriven shaft 10 carries the operating elements of a Geneva-stop mechanism comprising rollers 12 adapted to enter slots 15 in the driven member in such a manner that the shaft 13 is stepped twice for each revolution of the driving shaft, the length of the slots 15 ensuring, however, that the stepping takes place during only a short movement (about 36‹) of the rotation of the driving shaft. The shaft 13 drives through gearing 17, 18 a driving member consisting of a gear 20 on a shaft 19. This driving member is adapted to co-operate with a gear 24 driving switch mechanism through a clutching device the switch mechanism consisting of a brush structure 51 rotatable within a stationary commutator 54. The clutching mechanism, Figs. 11 and 12, comprises a pawl 31 adapted to engage a ratchet wheel 26 mounted to rotate with an intermittently-driven gear wheel. The pawl is pivotally mounted at 32 on a toothed wheel 29 and is biassed towards the wheel 26 by a spring 35. Normally, however, the pawl 31 is held clear of the teeth of the wheel 26 by a camming surface 38 in a recess in a wheel 30 movable relatively to the wheel 29, but held by one of its teeth 30a being held by the downturned end of a latching member 41 under the control of the armature 45 of a clutch control electromagnet 44. On energization of this electromagnet, however, the release of the tooth 30a of the wheel 30 allows the spring 35 to draw the pawl 31 against the wheel 26 so that the intermittent drive is transmitted to the contact brush 51 attached to the wheel 29. The movement of the wheel 29 causes a lever 39 to be rocked so that its laterally-bent end 46 engages the latching member 41 and ensures its re-engagement with the succeeding tooth 31a of the wheel 30. Thus the stepping of the contact member is controlled by energization of the clutch control electromagnet which may be under automatic or manual control. The intermittent making and breaking of the commutator contacts may control banks of lamps and a selective control in succeeding steps may be produced by the provision of a composite brush structure involving brushes of different lengths.