Patent GB-403817-A (GB)
Title: Improvements in controlling devices for variable speed gearing, particularly for motor vehicles
Filed: 1933-01-18
Abstract: 403,817. Controlling change-speed gearing. FORICHON, A., 70<bis>, Avenue de Suffren, Paris. Jan 18, 1933, Nos. 1720 and 1721. Convention dates, Jan. 18, 1932 and July 25, 1932. [Class 80 (ii).] In change-speed gearing for vehicles of the kind comprising constant-mesh gears and at least one pair of friction clutches, said clutches are operated through a pneumatic suction or pressure relay controlled by changes in the engine suction. In a form shown in Fig. 1, the suction in the induction pipe 33 through a duct 40 operates also the movable member or diaphragm 42 of the relay motor 41. The trigger part is a diaphragm 36 connected to a slide valve 37 and normally held down by a spring toggle 77. A chamber 36' is always connected by a pipe 35 to the induction pipe 33 and when the suction is sufficiently great, the parts 36, 37 rise so as to pass on the suction to the motor 41. This pulls a lever 22 to the right and so thrusts a pair of friction clutches 15, 18 to the left. The effect of this shift is to connect a larger wheel 4 to a driving-shaft 1 instead of a smaller wheel 7. On a driven shaft 2 there slides a clutchfaced gear 13, Thus for each gear position of the gear 13 effected by a manual lever 25 the effect of increased vacuum which accompanies increased engine speed is to change automatically to a higher speed, there being four speeds in all. The change back is also automatic. To disengage the drive, a pedal 55 is thrust down against a stop 58. This turns a cock 54 which opens the motor 41 to atmosphere at 59 and allows a spring 20 and a lost-motion link 61 by joint action to bring the pair of friction clutches 15, 18 to a neutral position. In a form shown in Fig. 2, the relay motor 41<1> is operated by vacuum in a reservoir 94 which is maintained through a valve from an engine-driven pump 97 or from the induction pipe 33. With a disengaging pedal 55 in the raised position shown, the motor 41<1> acts like the motor 41 of Fig. 1, the suction passing from the reservoir 94 by pipes 91, 40, 92, a cock 54<1> and a pipe 93 to the motor. To disengage the drive, the accelerator pedal, not shown, is released and the pedal 55 is depressed. Very little effort is required to depress the pedal 55, because this operation merely closes the cock 54<1> and opens a cock 54<2> so that suction is applied to the relay piston 42<1> from behind a piston valve 100 so as to pull the piston 42<1> to a position in which the friction clutches, not shown, are in neutral with the valve 100 closing a duct 103 admitting suction to the motor 41<1>. Two different arrangements are described according to which the accelerator pedal and the drive-disengaging pedal are combined in one. In Fig. 5 is shown an arrangement comprising also a centrifugal governor 120. The governor 120 is driven from a sleeve 6<1> constantly connected through a clutch drum 17<2> with the driven shaft 2. The governor acts on a lever 129 which controls the gear clutches conjointly with the trigger motor 130 which is operated automatically directly by the suction in the induction pipe 33. There are a pair of gear friction clutches 15<1>, 18<1> on the left for connecting the gears 4, 3 alternatively to the driving-shaft 1, as in Fig. 1. The gear 13 is in constant mesh, and, instead of its having a clutch face, the gear 4 is adapted to be clutched to the drum 17<2> by a friction clutch 15<2>. There are thus three friction clutches, a one-way clutch 27 providing connection to complete the four speeds. The three clutches are engaged by rotary expanding chambers 22<1>, 22<2>, 22<3> connected alternatively to a chamber 94<1> of compressed air by a distributing slide valve 121 operated automatically in accordance with engine and road-wheel speeds by the conjoint control lever 129. A lever 55 disconnects the drive. Specification 362,709 is referred to.