Patent GB-390858-A (GB)
Title: Improvements in or relating to power transmission mechanism
IPC: B60K17/02
Filed: 1931-08-13
Abstract: 390,858. Change-speed gearing. SALERNI, P. M., 23, Carlton House Terrace, London. Aug. 13, 1931, No. 22911. [Class 80 (ii).] Power transmission mechanism specially for motor vehicles comprises an hydraulic transmitter B, Fig. 2, between the engine and a change-speed gear C, additional means E for interrupting the transmission for coasting or facilitating changing speed, and means such as a valve 13 for varying the flow in the transmitter interconnected with means such as a brake 29 for arresting the driven shaft 16 of the transmitter, whereby the transmitter can be checked regardless of engine speed and with little or no braking effect on the engine. The transmitter B may be of a type described in Specification 362,952, [Group XXIX], with driving vane wheel 10 carried by a casing 11 fast on the engine shaft, not shown, and driven vane wheel 12 fast on a shaft 16 leading to the change gearing C. The gearing C of suitable type is operated by a control lever C<1>. The interrupter E is preferably arranged as an isolating-clutch between the change gearing C and a propeller shaft F. It may be a lockable one-way clutch, or a synchronized claw clutch. The clutch described is a modification of the Salerni clutch of Specification 306,636, [Class 80 (ii), Gearing, Variable-speed &c.]. The valve 13 adapted to be moved into the liquid circuit is carried on a plate 14 secured to a sleeve 15 operated through a collar 27, Figs. 4 and 6, by a fork 26 fast on a rock shaft 25 connected through a cam 21 and link 20 to a pedal 17. The pedal 17 is also connected by a link 35 to a sleeve 33 loose on the shaft 25 having an arm 32 which thrusts a strut 31 upwards and so tightens the brake 29 upon a drum 28 fast on the transmitter shaft 16. The cam 21 coacts with a fixed bowl 23 so that depression of the pedal 17 first tilts the cam so as to thrust the valve 13 into the liquid stream. Continued depression of the pedal raises the strut 31. Thus in the pedal 17 is combined the means for annulling the torque in the transmitter B and for arresting or stopping the driving-shaft 16 of the change gearing C. This combined control pedal 17 is, in the arrangement shown, connected by a link 45, Fig. 6, to a yoke lever 44 of the modified Salerni coupling E, which is normally pulled towards engaging position by a spring 48. Depression of the pedal therefore also opens the clutch E so that the change gearing comes to rest and operation by the lever C<1> is effected without shock. On release of the pedal, a free return movement by the spring 48 suffices to release the brake 29 and free the shaft 16. The driven member 38, Fig. 10, of the clutch E is rotating faster than the driving-member 37 and is prevented from engaging by an interposed synchronizer ring 40 which is rotated with and by the member 38 as long as that difference in speed remains, a frictionally-engaged ring 43a free-wheeling at 43 over the member 37. Friction at cones 43b between the rings 40, 43a is maintained by the spring 48. The yoke lever 44 through the link 45 prevents the pedal 17 from rising sufficiently to withdraw the valve 13 from the liquid circuit. The vehicle is now coasting. The shaft 16 is revolved by drag in the transmitter, and on accelerating the engine transmits sufficient motion to cause the clutch member 37 to overtake the road-wheel driven member 38, whereupon baulking seatings 41 are displaced and the driven member 38 snaps into engagement, effecting positive drive and allowing the pedal 17 to be returned to raised position with the valve 13 withdrawn from the liquid circuit and the engine driving full. The above sequence can take place for each gear change, while, for free-wheeling, it is only necessary to depress the pedal 17 sufficiently to check the circuit in the transmitter B and to open the interrupter E. For reversing, the pedal 17 is depressed to insert the valve 13 and to open the interrupter E, as in coasting, and, when the reverse gear is engaged, a lever 52, Fig. 6, through a link 51, and lever 50, Fig. 10, slides a member 49 over the clutch member 38, which member 49 has inclines 49a which turn the synchronizer ring 40 out of the way and allow the clutch to engage for the reversed drive. The change gearing may alternatively be epicyclic as described in Specification 346,846. Specification 361,281 also is referred to.