Patent GB-886606-A (GB)
Title: Process cycle controller
IPC: G05B19/02
Filed: 1960-05-23
Abstract: 886,606. Timed control of electric circuits. BRISTOL CO. May 23, 1960 [May 29, 1959], No. 18075/60. Class 118. [Also in Groups XXIX and XXXVII] In a process cycle controller a timing dial 11 (Fig. 1), normally driven at constant speed by a motor 21, causes a motor 40 to start operating in a first direction to drive the sequencing mechanism, mounted on shaft 60, which controls the sequential operation of switches 80, 81, and at the end of the cycle the sequencing mechanism reverses the direction of operation of the motor 40, whereupon this motor drives the timing dial 11 at high speed until the latter reaches its zero position ready for the start of another cycle. The normal drive to the timing dial 11 is transmitted thereto from motor 21 via a train of gears including the changeable gears 25, 26, 27, selected combinations of which may be installed to provide various time ranges for the cycle. Dogs 13 are mounted on the rim 12 of dial 11, each being held in position by the engagement of a set-screw 133 (Fig. 2) with the edge of a V-shaped groove 121 formed around the rim 12. Mounted on a bracket 100 (Figs. 5, 6) is an operating mechanism 57 which co-operates with the dogs 13 on the timing dial 11 and with pins 65 fixed into holes 64 of an indexing drum 63 mounted on shaft 60. When a dog 13 engages the pin 120 of the operating mechanism 57 it deflects the latch 114, against the force of tension spring 116, so that this latch 114 is freed from arm 102. The arm 110, urged by spring 107, then flies back in a counter-clockwise direction (Fig. 6) about its pivot 101 and raises switch arm 125 to close the micro-switch 126. This switch completes the circuit for motor 40 to drive in a forward direction, whereupon the one-way clutch 44 (Fig. 1) transfers the motion to shaft 60. When next a pin 65 engages roller 104 (Figs. 5, 6) it deflects arm 102 counter-clockwise so that its end 103 re-engages the opening 115 of the latch 114; and when pin 65 disengages from roller 104, the arm 102, urged by spring 106, returns to its normal position, pulling the arm 110 with it into a reset position, and causing the opening of switch 126. The motor 40 is thus stopped until switched on again by engagement of the next dog 13 with the pin 120. During a period when the motor 40 is running in the forward direction the cam discs 67 rotate with shaft 60 to control the switches 80, 81. One cam disc 67 is provided for each of these switches and has mounted thereon actuator members 70 (Fig. 7) which co-operate with a latching mechanism 82. As shown in detail in Figs. 8A, 8B the discs 67 have radial slots 68 spaced radially from holes 69. Each actuator member 70 consists of two L-shaped members 71 and 72 of spring steel, joined by welding at a common area forming a pin 73, the overlapping edges of the upper member being rolled over the lower one to stiffen the assembly. The longer ends of the L-shaped members are separated by a button 74 on the lower paddle-shaped member 71. A member 70 is installed by spreading the members 71, 72 over the edge of a cam disc 67 and moving it until the shoulder of the pin 73 falls into a desired slot 68 and the button 74 snaps into the corresponding hole 69. Each member 70 may be installed with its pin 73 on the right or left side (Fig. 7) of the cam disc 67 to initiate the " on " or " off " action, respectively, of the associated switch. A pin 73 on the right engages cam surface 87 of the short arm 85 thus disengaging the notch 91 from the shelf 88 of the long arm 83, whereupon the operating pin 90 of the switch, which may be of the plunger-operated pneumatic pilot valve type (80), or of the snap-action electrical type (81) (Fig. 1), falls and operates the switch to its " on " state. The next pin 73 on the left engages cam surface 92 of arm 83, thus lifting this arm and the switch pin 90 and engaging the shelf 88 in the notch 91 to hold the switch in its " off " state. Those index pins 65 not required in any given cycle are adjusted to project from the right of drum 63 (Fig. 5) in whose position they are ineffective, and the drum then drives until a final pin on the left stops the motor 40. Cam switch 78 (Fig. 1), however, is closed at this point and supplies power to the reverse field of motor 40. The clutch 44 is then disengaged, but clutch 50 is engaged and the timing dial 11 is thus driven at high speed in its normal direction, an overriding clutch in the normal drive train from motor 21 effectively disconnecting the latter motor. When the dial 11 reaches its zero position the dog 13A causes the operating mechanism 57 to operate switch 126, thus opening the reverse circuit of motor 40 and closing the forward one. Drum 63 is thus driven to a position intermediate two predetermined pins 65, at which cam switch 79 removes power from both motors. Specification 797,115 and U.S.A. Specification 2,633,951 are referred to.