Patent GB-640003-A (GB)
Title: Improvements in and relating to automatic control mechanisms for initialting and timing a number of processes
IPC: D06F34/30
Filed: 1947-02-28
Abstract: 640,003. Time switches. BRITISH THOMSON-HOUSTON CO., Ltd. Feb. 28, 1947, No. 5844. Convention date, March 1, 1946. [Class 38(v)] [Also in Group VIII] An automatic control ' mechanism comprises two cam discs, Fig. 10, one 15, of which has at least one arcuate slot 17 while the other 16 has a corresponding number of ribs 19 which project one into each slot, the cams being mounted on a timing shaft so as to be angularly adjustable in relation to each other to vary the interval between control operations effected by the slot and rib. The two discs 15, 16, Fig. 1, actuate a series of electric switches 13 and are driven through a clutch and gearing 3, 4 by a timing motor 2. The hub 24 of the disc 16 is journalled in the hub 22 of the disc 15, and the hub 22 is fixed to a sleeve 6 in which is journalled a shaft 5 driven from the motor 2 ; a friction ring 9 on the sleeve 6 is urged into engagement with one face of the gear wheel 4 by a spring 10. The disc 15, Fig. 10, has a series of rings of concentric arcuate slots 17, each ring corresponding to one of the switches 13. The disc 16 has a series of concentric arcuate ribs 19, which fit in the slots 17 of the disc 15, and being of less length than the slots 17 permit the turning of the disc 16 to a limited extent relatively to the disc 15; the ribs 19 are provided with a number of depressions for co-operating with the switches. By this arrangement the switches may be operated in the desired sequence both by the lands 18 between the slots 17 of the disc tively to the disc 15 provides for the adjustment of the time at which the first projection 21 of the disc 16 comes into effect to operate the corresponding switch. In the arrangement shown in Fig. 5, the switch is first operated at spaced intervals by the lands 18 of disc 15 between the points b, b<SP>1</SP> and points b", c; the next operation of the 15 and by the projecting parts 21 of the ribs 19 of disc 16. Rotation of the disc 16 relaswitch occurs at the point d by the action of the land 21 of the disc 16 and the time of the operation can be varied by rotating the disc. The disc 15 is keyed to a cup-shaped dial 26, Fig. 1, and the discs 15, 16 are held in frictional engagement with each other by a spring 25 between the dial 26 and disc 16. An operating knob 34 is screwed to the disc 16, arcuate slots being provided on the dial 26 to permit the passage of feet 35 on the knob 34 and the desired movement of the disc 16 relative to the disc 15. The dial 26 also has an arcuate window 32 through which a legend-carrying sector 31 attached to the disc 16 is visible. The. friction between the discs 15, 16 is less than that between the friction ring 9 and gear wheel 4 so that whenever the knob 34 is turned the disc 16 moves relative to the disc 15 without moving the latter disc relative to the timing motor. Turning of the dial 26 moves both discs relative to the timing motor. As applied to an automatic washing machine in which the various operations are controlled by the switches 13, the cycle commences at the point a, Fig. 5, and the lands 18 and depressions 17 on the disc 15 up to the point c control the agitation and spindry operations of the soaking period. The agitation period from c to d, of the washing cycle is controlled by the depressions between the trailing ends of the final lands of the disc 15 and the leading ends of the initial lands on disc 16 and is adjustable. The lands and depressions for the " wash-spin " and " rinse-agitate " periods from d to g are part of the disc 16. If desired the innermost switch may be operated from the point f to the end of the cycle irrespective of the relative positions of the discs, in which case the disc 15 is provided with an operating land overlapping the adjacent land on the disc 16. After the machine is brought to a stop, the dials may be turned as a unit to a further point to provide for a period during which the water in the machine is pumped to a drain.