Patent GB-832007-A (GB)
Title: Improvements in or relating to power operated change speed transmission selectors
IPC: F16H61/02
Filed: 1957-07-10
Abstract: 832,007. Change-speed control. FORD MOTOR CO. Ltd. July 10, 1957 [July 19, 1956], No. 21921/57. Class 80 (2). [Also in Group XXXVII] A motor vehicle change-speed transmission selector comprises a reversible electric motor 21 which rotates when one or other of five pushbuttons P, R, N, D, L is depressed to render operative one of the corresponding ratio ranges &c. in an automatic change-speed gear, the motor driving through a shaft 42 to a rotary switch having wiping contacts on a disc 41 engaged by stationary brushes 44-48, a non- conducting portion between the wiping contacts eventually engaging the brush associated with the depressed push-button to switch off the current and bring the motor to rest. A relay 63 is energized when the motor vehicle ignition is switched on to condition switches 60, 64 to the position shown. An accumulator 71 is then connected through a circuit-breaker 69, a relay 68 and the switch 64 to a brush 43 on one side of the push-button brushes 44-48. Simultaneously, the accumulator 71 is connected through a second relay 73 to a brush 49 on the opposite side of the push-button brushes 44-48. As shown, the push-button N, corresponding to neutral in the change-speed gear, has been depressed, and the associated brush 46 is engaged by the non-conducting portion of the wiping contacts. In this position, brushes 91, 92 are connected by a conducting strip on the rotary switch, so that an engine starting motor 75 is rendered operative. As soon as the motor vehicle engine fires, a vacuum responsive switch 76 connected to its inlet manifold opens, and stops the engine starter from functioning. If either the push-button D or the push-button L is depressed to select the drive or low ranges in the change-speed gear, mechanical interlock mechanism (not further described) opens the push-button switch N, and a circuit is made through the push-button D, or L, the associated brush 44 or 45, the wiping contacts on the rotary switch 41, and the brush 43 to the switch 64 and the relay 68. Switches 82, 83 and a circuit controlling the motor 21 are then conditioned by the relay 68 to connect the accumulator 71 to a field coil 90 and the motor armature 89 to cause the motor to turn anti-clockwise. As the motor 21 turns, it turns the wiping contacts 41 until the non-conducting portion engages the brush 44 or 45 of the depressed push-button. The circuit is then broken and the motor comes to rest. A braking resistor 95 between the motor armature 89 and the field coil 90 allows back E.M.F. to assist in bringing the motor to rest in its new position. If the push-button P is now depressed, corresponding to the park position in the automatic changespeed gear, the push-button switch L or D is automatically opened by the mechanical interlock, and a circuit is completed through the push-button switch P, the switch 61 and the brush 48 to the wiping contact 41 and thence through the brush 49 to the relay 73. Energization of the relay 73 conditions a switch 84 to connect the accumulator 71 to the armature 89 of the motor 21 and to a field coil 87, so that the motor 21 rotates in a clockwise direction. The motor 21 and the wiping contacts 41 then turn until the non-conducting portion of the wiping contacts engages the brush 48. A switch 58 in the circuit of the P push-button switch, and also of the R push-button switch corresponding to reverse, is opened when the vehicle is moving and prevents the park or reverse position being reached except when the vehicle is at rest. When the reverse push-button R is depressed, the motor 21 and the wiping contacts 41 turn until brushes 93, 94 are connected, thus causing a reversing light 79 on the vehicle to be switched on. If the motor vehicle ignition is switched off, the relay 63 is de-energized, the switch 61 connects the switch 58 to the brush 48 and the switch 64 breaks the circuit to the relay coil 68. The relay 73 is then energized through the brushes 48, 49 and the electric motor 21 rotates and automatically selects the park position in the change-speed transmission selector. Specification 808,409 is referred to.