Patent GB-1017906-A (GB)
Title: Electric time switch
IPC: G04C23/18
Filed: 1963-07-10
Abstract: 1,017,906. Time switches. NEFF-WERKE CARL NEFF G.m.b.H. July 10, 1963 [July 11 1962], No. 27313/63. Heading H2B. A time switch comprises a synchronous motor 6 (Fig. 1) driving a shaft 8 at six revolutions per hour and a digital counter A indicates clock time, adjustment by knob 15 being possible by virtue of a slip clutch 7. The first drum 1a is marked 0 to 9, and the second drum 2a from 0 to 5 to indicate together minutes up to 59, and the third drum 3a is marked to indicate hours from 0 to 12. Two similar digital computers B and C are also driven from shaft 8 but via differential gears comprising assemblies 10, 11, 12, 13 with suffixes band c respectively. The drums of counters B and C need not carry actual markings but each has a cam recess in its periphery for operating the switch as described below. Two further digital counters D and E, marked as counter A, are driven by shafts 8d and 8e by means of coarse and fine setting knobs 28 and 25 via gearing and slip clutches 21d and and 21e. Pawls 20d and 20e prevent shafts 8d and 8e rotating in the opposite sense to that indicated by the arrows thereon; this provides for setting of shaft 8d by rotation of knobs 28 and 25 in one direction, and setting of shaft 8e by rotation of the knobs in the other direction. The shafts 8d and 8e displace counters B and C via their respective differential gears, and the cam recesses in these counters are aligned in switchoperating position only when the time indicated on respective counter D or E agrees with that on clock counter A. Thus if counter D, for example, is adjusted the counter B does not effect switch operation until motor 6 has driven counter A to the time indicated on counter D. Counter E similarly determines the delay in switch operation by counter C. Switch operation.-Fig. 2 illustrates the operation of a switch 20f by the drums 1b, 2b, 3b and 1c, 2c, 3c of counters B and C, respectively. Bell-crank levers 5f and 6f carry cam followers 1f and 2f, respectively, and are urged by springs 11f and 12f such that when all recesses in the associated drums are aligned with the followers bell-crank levers 9f and 10f are acted on. The ends of levers 9f, 10f and a further lever 13f normally lie in the path of staggered projections 15f, 16f and 17f, respectively, on a plate 14f which is urged upwardly by a spring 21f and carries cams 18f for co-operation with actuating lever 19f of switch 20f. Plate 14f is initially retained in the position shown by lever 9f and projection 15f, and a cam 18f holds switch 20f in the open condition. When motor 6 has driven counter A to the time set on counter D the recesses of counter B are aligned and lever 9f is moved to release projection 15f, whereupon plate 14f moves up until projection 16f engages lever 10f, and the switch follower 19f falls between cams 18f to close switch 20f. When the time set on counter E is reached, counter C allows retraction of lever 10f from projection 16f and the plate 14f rises until restrained by lever 13f engaging projection 17f. Lever 19f is now lifted by the other cam 18f and switch 20f is opened. The plate 14f is reset for a further cycle by depression of button 22f. The time switch may be rendered ineffective at any time by depression of an over-ride button 23f which moves a rod 25f to withdraw all the levers 9f, 10f and 13f, whereupon the plate 14f moves up beyond its normal limit to allow lever 19f to move clear of cams 18f and switch 20f is closed.