Patent GB-1531061-A (GB)
Title: Transmission systems for vehicles
IPC: F16H63/40
Filed: 1976-01-07
Abstract: 1531061 Change-speed control SOC ANON AUTOMOBILES CITROEN 7 Jan 1976 [15 Jan 1975] 00409/76 Heading F2D In an automotive drive line comprising a series sequence of an input shaft 1, a torque converter or coupling 3 giving rise to idle drag, a first intermediate shaft 2, a change speed gear 4 (not described), a second intermediate shaft 2a, a forward-neutral reverse gear 5 controlled by a lever 11 having Drive, Neutral, Reverse and Park settings, and a final output shaft 6, either intermediate shaft 2, 2a being provided with a brake 7 to overcome coupling idle drag, and thereby facilitate shift in the reverse gear 5, the brake 7 is applied by fluid pressure controlled by a valve 25 actuated by a solenoid in an electric circuit, including a first, normally open, switch 29 closed by D or R establishing movement of the manual lever 11 from any setting, but not by its movement from D or R to N nor from R to P, and a second switch 31 which is normally closed by a conductive double-acting spring 23, washers 17a, 17b and stops 19-22, in a yielding link 12 between the control lever 11 and the FNR selector of the reverse gear 5. The spring 23 yields to open the brakevalve circuit if the FNR selector encounters excessive resistance, e.g. due to clutch teeth butting end on. Thus initial movement of the manual lever towards D or R closes the lever switch 29 energizing the anti-drag brake 7. In the absence of abnormal resistance the shift proceeds, with the link switch 31 remaining closed, the brake 7 being de-energized on completion of shift by the opening of the lever switch 29. Resistance to the shift causes the link spring 23 to yield, opening the link switch 31 momentarily to deenergize the brake 7, permitting sufficient rotation for engagement to take place. Operation of the switch 29 by the shift lever 11 is as follows. Slidable axially in the lever 11 is a rod 34, which can be depressed by a manual catch 36 against a spring 37, and carries a projecting pin 38 tracking in an irregular opening 40a-40f in a fixed support plate 33, and including notches 40a, 40b, 40c, 40d, which, when engaged by the lever pin 38, define DNR and P settings of the lever 11. Downward movement of the pin 38 rocks two lever-plates 41, 42 on fixed pivots 43, (44) and overlying an actuating button 29a of the switch 29. In the initial N position shown, the pin 38 occupies the neutral notch 40b. To move the shift lever 11 clockwise (Fig. 2) towards the Drive notch 40a or counter-clockwise towards the Reverse notch 40c, the catch 36 is first depressed, causing the pin 38 to depress the leverplates 41, 42 which depress the switch button 29a closing the switch 29 and thereby applying the anti-drag brake 7. The pin 38 then moves in the aperture section 40e as the shift lever 11 is pivoted to D or R. On reaching D, the pin 38 enters a cut-away part 42a of the lever plate 42, permitting the lever plates 41, 42 to be raised by a common spring 45, and hence the lever switch 29 to be re-opened by its spring 30, thus releasing the brake 7. Release of the catch 36 then permits the pin 38 to enter the notch 40a, locking the lever in Drive. During the return movement from D to N, the initial depression of the pin 38 causes it to pass through the lever cut-out 42a and under the lever plate 42, where, acting on an inclined edge 48 of the lever plate it raises the latter to permit the pin 38 to reach and enter the N notch 40b without operating the switch 29. Release of the catch 36 in N permits the pin 38 to rise in the N notch 40b, first lifting, and then releasing both lever plates 41, 42, to the N position shown. R is selected by manipulation of the selector lever such that the pin 38 enters the notch 40c. In the subsequent movement to the P notch 40d, the pin 38 traverses the aperture section 40f, where it acts on a part 46 of the lever plate 41 to raise and release the lever plate 41 ineffectively, and ensuring that, on the return movement of the pin 38 from P to R, the lever plate 41 is depressed by action of the pin on the part 46 to close the brake energizing switch 29. The P position of the lever 11 may be located adjacent the D position, and the locating notches 40a, 40c, 40d may be omitted as may also be one, 42, of the lever plates.