Patent GB-601134-A (GB)
Title: Automatic position control apparatus
IPC: H03J5/18
Filed: 1945-07-20
Abstract: 601,134. Electric control systems. STAN - DARD TELEPHONES & CABLES, Ltd. July 20, 1945, No. 18641. Convention date, July 28, 1944. [Class 40 (i)] In apparatus for setting a shaft, such as that of a radio tuning element to a predetermined position the shaft is coupled to a pair of shafts, themselves coupled by gearing and each carrying one of a pair of cams which are engaged by a preselected member when the shaft has been driven to the predetermined position. As described, a number of pairs of cams are employed so that the system may be stopped in a corresponding number of positions. To this end the two shafts 1 and 2 (Figs. 3 and 7) one 1 of which is coupled to a contactor member working on an inductor, are connected by step-down gears, and carry two sets of cams 13 and 21, whose positions on the shafts may be adjusted by merely applying sufficient force in the case of 2, and by slacking nut 17 in the case of 1. To set the shafts to a predetermined setting, a selector switch, Fig. 11, is set to a corresponding position so that one of the release electromagnets in banks 59 and 60 (see also Fig. 4) is energized. A start switch is then pressed to energize a solenoid 80 momentarily (see also Fig. 5) so that armature 79 moves to close contacts 99 and pull release bar 74, Fig. 4, (see below) to the left, disengaging whichever latch bar member 54 happens to be engaged with its respective pair of cams. The energization of one of the electromagnets in the banks 59 and 60 causes a corresponding stop member 57 to disengage an associated member 54, which pivots clockwise to engage the surfaces of associated cams 13 and 21, under the influence of spring 73. A similar member 94, Fig. 2, follows member 54, under the influence of a spring 95, and a shoulder 96, and moves arms 81 and 82, Figs. 5 and 11, over contacts 83 and 84-87. Arm 82 comes to rest on contact 85 or 86, according to which half of cam 21 member 54 engages. These contacts are respectively in the circuit of motor control relays 103 and 108 (one for each direction) which cause motor 35, Fig. 3, to run to bring recess 91 under detent 55 of member 54 with the shortest possible movement so that when the recess 20 in cam 13 next comes under detent 52 both. detents engage the respective recesses, and stop the shafts. To reduce shocks when this happens, an intermediate pinion 43, Fig. 8, in the gear train from the motor is coupled to its shaft by a friction plate 49. Motor 35 is de-energized since arm 82 is on blank stop 87. The release bar 74 is operated by the rotation of a freely mounted pinion 68, Fig. 5, which meshes with a sector gear 69 on a shaft 70 carrying a similar sector gear 71, Fig. 3, which meshes with a pinion 72, attached to a lever 76, which is manually operated when it is desired to set up the cams, or automatically operated by pin 78, Fig. 4, coupled to armature 79 when in normal use. Fig. 9 shows a limit switch and stop in which contacts 100 (also Fig. 11) are opened when shaft 2 rotates sufficiently for pin 118 to drop on to the lower surface of cam 114. This also causes a mechanical stoppage by reason of the engagement of pin 119, with abutment 121 associated with shaft 1. The Specification as open to inspection under Sect. 91 also suggests that the system may be modified by interchanging the recesses and detents on the cams and latch members. This modification is not included in the Specification as accepted,