GB467765A - Improvements in motor-driven apparatus for the timed control of a cycle of operations - Google Patents

Abstract

467,765. Electrically - actuated valves. BRISTOL'S INSTRUMENT CO., Ltd. May 19, 1936, No. 14196. Convention date, May 31, 1935. [Class 135] [Also in Group XXXVII] A valve or switch 48 controlling a process is operated by a cam-follower 45 co-operating with a cam 11 which is driven, always in one direction by a reversible motor 21 through one of two trains of gearing, the particular train selected depending on the direction of rotation of the motor, and the gearing being such that one train gives a faster speed to the cam than the other. The motor drives a wheel 24 and this is connected to a wheel 14 fixed to the cam, through gearing 17, 15, and also through gearing 25, 26, 18, 16. Ratchet mechanisms 19, 20 connect wheels 17, 15 and 18, 16 together for one direction of rotation but allow them to slip for the other direction. The cam has a narrow portion 35, a broad portion 36, and an intermediate portion 37, the angular extent of the portion 36 being adjustable by a detachable and turnable sector 38, and in addition to operating the valve 48 it operates switches 46 47 controlling the motor. From the stationary position shown, closure of a switch 49 completes the circuit to the winding 22 of the motor 21 which then rotates in the direction of the arrows. The pawl 19 drives the wheel 15 and cam 11, while the pawl 20 driven counterclockwise slips over the ratchet wheel 16 which is driven clockwise from the wheel 14. The cam is thus driven fast and the cam-follower 45 moving on to the part 36 opens the valve 48, closes a retaining circuit 46 for the motor and operates the switch 47 into its other position in which the winding 23 of the motor is energized and the motor reverses. Pawl 20 now drives and pawl 19 slips with the result that the cam moves slowly till after a time determined by the length of the portion 36, the cam follower 45 drops on to the part 37, closing the valve 48, changing over the switch 47 but keeping the switch 46 closed. The motor reverses again to its original direction and the cam rotates rapidly till the camfollower 45 drops into the notch 35 and the switch 46 opens stopping the motor and bring- ing the parts to their original position ready for the next actuation of the switch 49. Instead of a ratchet-and-pawl, a clutch arrangement, Fig. 4, (not shown) may be used.