Patent GB-900556-A (GB)
Title: New or improved arrangement for pre-selecting and engaging the speeds in a change-speed gear
Inventor: BURCKHARDT MANFRED
IPC: F16H61/02
Filed: 1960-06-17
Abstract: 900,556. Change-speed control. DAIMLERBENZ A.G. June 17, 1960, No. 21360/60. Class 80 (2). A change-speed control mechanism comprises a hand-operated gear-shift lever moved to preselect a desired ratio, the lever simultaneously closing contacts in a relay circuit actuating a servomotor, the circuit being made when the gear-shift lever is released, whereupon establishment of the selected ratio follows without further manual actuation. In one form, the change.speed gear 10 of a motor car follows the usual clutch 14 and has its ratios preselected by hand operation of a gear shift lever 12 connected through links &c. 13 to selecting mechanism 11. Operation of the gear shift lever 12 closes contacts 17 to energize a relay 18 which moves a switch contact to connect a source of potential to a contact 19<SP>1</SP>, this potential then being applied through a closed switch 29 to a first hold-on relay 26 and a second relay 20. Energization of the relay 26 closes a switch 26<SP>11</SP> which connects a source of potential through a line 28 to the closed switch 29, and energization of the relay 20 closes a switch 21 in a line between a contact 19<SP>11</SP> of the relay switch 19 and a further relay-operated switch 23. Since the gear-shift lever switch 17 is now operated to condition the switch 19 so that its movable contact is away from the contact 19<SP>11</SP>, the line 22 containing the switch 21 remains de-energized. Having operated the gear shift lever 12 to select the desired ratio in the mechanism 11, the driver of the motor car releases the gear-shift lever, which opens the contacts 17 so that the relay 18 is de-energized and the relay switch 19 is restored to the position shown, when its movable contact engages the contact 19<SP>11</SP> of the line 22. The line 22 is now energized, the holding relay 26 maintaining the circuit to the relay coil 25 to hold the switch 21 closed. Potential applied through the switch 19 and the line 22 now serves to energize a relay coil 34 which closes the switch 23 to connect the source of potential to a line 24 controlling the actuation of an inlet manifold depression energized servomotor 15 which proceeds to disengage the main clutch 14. Initiation of clutch disengaging movement acts through linkwork 30 to open the normallyclosed switch 29 of the holding relay 26, which latter accordingly opens and simultaneously de-energizes the relay coil 25 to open the switch 21. However, the relay-operated switch 23 is provided with a holding circuit 31 containing a closed switch 32, so that the line 24 controlling the clutch disengaging servomotor 15 remains energized. Accordingly the clutch disengaging servomotor 15 continues to operate, and acts through linkwork 16 to establish the ratio preselected in the change-speed gear 10 by actuation of the gear-shift lever 12. On completion of the ratio establishing movement, a linkwork connection 33 between the main clutch 14 and the holding switch 32 opens the latter, so that the holding circuit 31 of the relay-operated switch 23 is broken, and the latter switch opens. The line 24 leading to the clutch disengaging servomotor 15 is de-energized, and the main clutch re-engaged. In a modified form, Fig. 2 (not shown), a spring connection is placed in the link 16 between the main clutch 14 and the ratioestablishing mechanism, so that in the event of teeth in the gearing not sliding into mesh, this spring is compressed, until a switch is operated to close its contacts and thereby energize a relay controlling a normally-closed switch in the line 24 leading to the clutch-operating servomotor 15, to open this switch and thus stop operation of the servomotor. The control mechanism then returns to its initial position, when the cycle of ratio establishment recommences, a succession of attempts to establish the ratio then being automatically made until the teeth slide into mesh. Specification 898,266 is referred to.