Patent GB-712118-A (GB)
Title: Improvements in and relating to the drive of continuously reversing apparatus
IPC: D06F34/08
Filed: 1951-08-28
Abstract: 712,118. Gearing for stopping and starting machinery. NEWBERY, S., and NEWBURY, Ltd., S. Aug. 28, 1952 [Aug. 28, 1951], No. 20238/51. Class 80 (2) [Also in Groups XXXIV and XXXVII] The clutch between a continuously and automatically reversing electric motor and cyclically driven apparatus is engaged only after the motor has reached its working speed and is disengaged only after the motor has substantially stopped. As shown the impeller of a washing machine is driven from a pulley 1 which is slidable on the shaft 2 of a reversible electric motor M and is normally held by a spring 5 with a clutch 3 engaged but is movable, by means of a lever 4 pivoted to a bracket 10 at 15, to a disengaged position. One arm of the lever 4 is actuated by a solenoid C the armature 16 of which actuates a lever 11 pivotally mounted at one end and connected by a link 13 to the lever 4. A brake pad 8 carried by bell crank levers 25, pivotally mounted about pins 26 on the bracket 10, engages a disc 9 on the shaft 2 when a solenoid B is energized. A lever 12 pivotally mounted at one end is connected to the armature 27 of the solenoid B and, by rods 23 carrying spring loaded abutments 24, to the levers 25. These levers are slidable on their pivots 26 (Fig. 16) under the braking drag to actuate, by means of arms 31 integral with the levers, one or other of two micro-switches S5, S6 according to the direction of rotation for a purpose later described. When the brake is disengaged springs 30 centralise the levers 25 and the switches are in their normal positions. A switch S1 having four positions shown diagramatically in Fig. 2 is operated by the levers 11. 12 moving respectively, when either solenoid is energized, plungers 20, 28 which co-operate with abutments 22, 29 to rotate .the switch through 90 degrees from one position to another. The switch S1 is connected in the supply to the motor in such a manner that in the positions 1 and 3 the motor is not energized and in the positions 2 and 4 it is energized for opposite directions of rotation. It is so arranged that energizing the solenoid C to disengage the clutch moves. the switch S1 to one of the positions 2 or 4 and energizing the solenoid B to engage the brake moves the switch to one of the positions 1 or 3. A switch S2 having starting and stop buttons 6, 7 is provided between the supply lines L1, L2, L3 and the motor. A centrifugal switch. S3 opens when the motor reaches a predetermined speed. A timing switch S4, Fig 3, is driven by a motor indicated by MS4 '  when the starting button 6 is pushed and operates to control the driving period of-the motor M until the button 7 is pushed. The operation is as follows:- The button 6 is pushed-energising the motor MS4 and the solenoid C to disengage the clutch 3 and simultaneously move the switch S1 to position 2 or 4. When the motor reaches a predetermined speed the. switch S3 opens and the solenoid C is de-energised the clutch then engaging and driving the pulley 1 until the switch S4 competes a circuit to energize the solenoid B which in turn applies the brake 8 and simultaneously rotates the .switch S1 to position 1 or 3. The circuit through the switch S4 is only transitory but as soon as the brake 8 is applied the drag moves the levers 31 to actuate one or other of the switches S5, S6 to maintain the brake operating solenoid B energized and to open the circuit through the clutch disengaging solenoid C which would otherwise be closed by the switch S3 as the motor slowed. When the motor slows sufficiently the drag on the brake 8 is overcome by the springs 30 which return the actuated switch S5 or S6 to its normal position, breaking the circuit through the solenoid B and completing the circuit through the solenoid C. The brake and clutch are thus disengaged together the switch S1 being: moved simultaneousity to a motor energized position the motor then rotating in the reverse direction to that in the preceding energized position of the switch S1. The motor continues to reverse in timed sequence until the button 7 is pressed. The invention is stated to be applicable also to the drums or cages of tumbler dryers, dry cleaning plant and the like which are subject to reversals of the order of six per minute.