Patent GB-659708-A (GB)
Title: Gear synchronizing device
Filed: 1949-10-10
Abstract: 659,708. Change-speed gearing; operating clutches. WICKBERG, K. G. E. Oct. 10, 1949, No. 26007. [A Specification was laid open to inspection under Sect. 91 of the Acts, April 20, 1950.] [Class 80(ii)] In constant-mesh variable-speed gearing for motor vehicles with dog clutches for bringing in the various speeds, toothed balking rings 6, spring-pressed into frictional engagement with the driving dog members 2 and having limited angular movement relative to the driven dog members 3, are arranged to prevent engagement of the dogs on down-shifts until the speeds are synchronized, the dogs having chamfered faces to facilitate engagement on upshifts. During down-shifts, the engine is accelerated either by the movement of the gear lever 12 towards the new position or by over-depression of the clutch pedal 13, the operation being accompanied by double-declutching effected in the first case, by normal double actuating of the pedal 13 and, in the second case, by overdepression of the pedal. As shown in Figs. 1, 2, the lever 12 is mounted in a member 19 which is normally held central by springs 35, 36 and which, on moving out of central position, moves downward a rod 20 resting on a lever 21 fixed on a spindle 54 carrying a lever 22, the lower end of which is connected to the engine accelerating means. A link 24, passing through a projection 33 on the lever 22 and carrying, between the projection, an abutment, is connected to the. upper arm of a lever 25 pivoted at 30 on the pedal 13, the lower arm being connected by a link 26 to the clutch throw-out fork 55. In making a down-shift, pedal 13 is depressed, the lever 25 reacting against lever 22 so that the clutch 11 is disengaged, and the lever 12 is moved to neutral. The pedal 13 is now temporarily released to engage the clutch, and the lever 12 is moved towards the new gear position. As the balking ring prevents engagement of the dog clutch, the lever 12 pivots about its lower end, moving the member 19 and causing the rod 20 to move downwards, thus turning the lever 22 and thereby accelerating the engine. During this movement the lever 25 is also rocked, taking up the play between the fork 55 and the throw-out bearing 29 without causing disengagement of the clutch. When synchronism is reached, the pedal 13 is again depressed to declutch, and the movement of the lever 12 is completed, the member 19 being returned to its central position, after which the pedal 13 is released. In the form shown in Fig. 5, the link 24 connected to the upper arm of the lever 25 bears against an abutment 33 on a spring-loaded rod 34 connected to a lever 61 connected to the piston of a hydraulic servomotor 38 controlled by a valve 40. In making a downshift, the pedal 13 is depressed to declutch and the lever 12 is moved to neutral. The pedal is now depressed further so that a projection 41 thereon operates the valve 40 to energize the servomotor 38, whereby the lever 61 is turned to withdraw the abutment 33 so that the clutch re-engages. The pedal is still further depressed to operate means 39 for accelerating the engine. When synchronism is reached, the pedal is released sufficiently to decelerate the engine and deenergize the servomotor and disengage the clutch. The gear movement is now completed and the pedal 13 released.