Patent GB-190613246-A (GB)
Title: An Improved Speed Gear for Motor Cars and the like.
Inventor: TACCHI PERCY GEORGE
Filed: 1906-06-08
Granted: 1907-06-08
Abstract: 13,246. Tacchi, P. G. June 8. Variable-speed gearing; c l u t c h e s. - Relates to change-speed gearing for motor-cars and the like in which the gear-wheels are always in mesh and the drive is obtained at the lower speeds t h r o u g h r a t c h e t clutches, the changes of speed being effected by friction clutches. Means are also provided for checking too rapid movement of the operating pedal, setting a limit to its motion by a hand-lever, and interlocking the reversing and forward gears. Fig. 1 shows a plan of the invention as applied to a -two-speed gear, Fig. 3 an enlarged sectional plan, and Fig. 6 a side elevation of the hand-operating mechanism. The double external clutch member c may be formed integral with the engine fly-wheel d, the end of the crank-shaft being reduced at c<3> to fit in the end of the driven shaft b<6>. One of the internal clutch members d<2> is mounted upon the driven shaft b<6>, while the other member d<3> is secured upon a sleeve e which drives the countershaft g<2> through the toothed gearing h, g<15>. The two clutch members are forced apart by a spring e<2>. A toothed wheel g<1> loosely mounted on the countershaft g<2> is connected thereto by a clutch on the reversing- pinion o<3> when the latter is out of action; the wheel g<1> gears with a wheel g loose on the shaft b<6>, but driving it when required through a ratchet clutch consisting of ratchet teeth on the wheel g, which engage spring-pressed pawls on a disk g<4> keyed to the shaft. At the second speed, only the clutch d<3> is engaged, motion being transmitted through the sleeve e, countershaft g', and ratchet gear g<12> to the shaft b<6>. At the high speed, both clutches are engaged so that the engine shaft drives the shaft b<6> directly, while the ratchet gearing allows the shaft b<6> to overrun the wheel g until the speed is such that the centrifugal force lifts the pawls g<12> clear. The shaft b<6> and sleeve e are both adjusted longitudinally to engage or disengage the clutches by means of pivoted levers i, i<1>, connected by links i<4>, i<5> to a rotary disk j<2>. The disk is keyed to a shaft j<3>, and is provided with cam slots j, j<1> with which rollers on the links i<4>, i<5> engage. The disk is rotated so as to disengage the clutches by a link k operated by a foot pedal, movement in the opposite direction being effected by the clutch spring e<2>. When both clutches are disengaged, the operating disk j<2> is in the position shown in Fig. 6. To engage the second speed, the disk is partly rotated, so that only the link i<5> and corresponding clutch are operated, the shaft j being partly concentric with the shaft j<3>. Further movement of the disk operates the link i<4>, so that both clutches are then engaged giving the direct drive. A dash-pot l<2> prevents too rapid engagement of the clutches while allowing rapid disconnexion. The extent of the movement of the disk j<3> is limited, when the clutches are being engaged, according to the setting of a hand-lever n, the connexion between the two, as shown in Fig. 6, comprising a rod m<1> having nuts upon its end, and upon which is free to slide a slipper m<2> pivotally connected to an arm m<3>. The reversing-gear of ordinary type comprises a pinion o<3> which serves to clutch the wheel g' to the countershaft g<2> during forward motion as stated above, but when slid away from the wheel g' drives the toothed wheel o keyed to the shaft b<6> in the reverse direction at the second speed through the medium of an idle pinion mounted upon another countershaft. The pinion o<3> is operated from a hand-lever m<8> freely mounted upon the spindle m<4> by means of a rod o', bell-crank levers o<5>, s, and link-work. To prevent operation of the reverse when the high speed is in gear, the lever n is provided with a plate n<2> which projects into the path of the reverse lever m<8>.