Patent GB-457068-A (GB)
Title: Improvements in and relating to change-speed mechanism
Filed: 1935-10-03
Abstract: 457,068. Controlling change speed gear and clutches. BENDIX AVIATION CORPORATION, 105, West Adams Street, Chicago, U.S.A. Oct. 3, 1935, No. 27304. Convention date, Oct. 4, 1934. [Class 80 (ii)] Electro-pneumatic control of change-speed gearing on a motor vehicle, comprises a singleacting transverse gear-selecting fluid-pressure motor 520, Fig. 34, and a double-acting gearestablishing fluid-pressure motor 500, the former being controlled by a manual preselector switch, the latter by the said switch in conjunction with a self-operated switch. The movements of the lever 274 of the manual preselector switch simulate those of a conventional gate-guided lever. A preselected shift is rendered effective by release of the accelerator pedal 78, which, in some cases, through a common valve 76, supplies engine-suction to a main-clutch withdrawal motor 60 and to the shifter motors, the clutch-motor closing a switch which completes the circuit of preselected solenoid-valves controlling the shifter motors. Means may be provided for automatically neutralizing the gear by the combined stopping of the engine and release of the accelerator pedal, and such means may also effect re-cranking of the engine. A mechanical interlock described below, may be provided between the gear-strikers and the accelerator-pedal to prevent depression of the latter while the former are in any position intermediate neutral and gear-engaged positions. In Figs. 34-37, the cross-shift diaphragm-motor 520 is energized to move a shifter-lever 504, transversely into engagement with a striker-rod 580 for low-speed and reverse, against an internal spring, which permanently biasses the shifter-lever 504, in the direction of a striker-rod 582 for second and high-speeds. A double-acting fluid-pressure piston motor 500, gives the selected striker-rod its longitudinal engaging movement. As shown, the gear-establishing piston-motor 500 acts on the shifter-lever 504 by turning a crank-shaft 510, which is bodily slid transversely by the cross-shift motor 520 acting through a bellcrank lever 526. A hand shifter-lever, carried as an accessory in the vehicle, may be fitted into a socket on top of the lever 504 for emergency manual operation. In Figs. 2-5 (not shown), and also in Fig. 1, control is through a slide-bar 22 which lies along the top of the gear-box, and passes between rollers on a transverse bar 42, which is slid laterally by the cross-shift motor 34 to pivot the slide 22 laterally about its rear end for gear selection, the slide 22 being slid longitudinally, for gear engagement, by a double-acting motor 24 secured to the vehicle, and acting through a lever 32. In a modification of this form, Fig. 33 (not shown), the slide bar slides in a longitudinal path only and has pivoted at its forward end, a transversely movable link connecting it with a depending lateral extension of a ball-mounted shifter-lever. The crossshift and gear-establishing motors are controlled by three two-way solenoid-valves which, in Figs. 34, 40, and 41, are shown in a unit 530 comprising independent valves 572, 574, 576, which are normally spring-biassed into a position in which they vent the motors to atmosphere through an air cleaner 540, and, when energized, connect the motors individually to an inlet 542 for engine-suction. In Fig. 8 (not shown), the two valves for the gearestablishing motor are formed integrally and are operated by opposed solenoids 192, 194 in a unit 82, Figs. 1 and 25, the single valve 214 of the cross-shift motor being disposed at right angles thereto. A manual preselector switch, for controlling the solenoid-valves, comprises a miniature lever 274, Figs. 15, 16, and 18, carried on a bar 226 and guided in an H-gate 224 in a casing 216, bolted to the steering column 222. A spring 298 constantly biasses the lever 274 to the right of Fig. 15 towards the channel for second and high speeds. Leftward movement into the low-speed and reverse channel closes contacts 300, 302, 304 which directly operates the solenoid-valve to energize the cross-shift motor 34, Figs. 1 and 25, or 520, Fig. 34, and bias the gear-shifter member towards the lowspeed and reverse channel. Turning with the switch-bar 226 is an insulated plate 236, carrying a contact stud 252, permanently connected to an input lead 240 through an annular metal plate 246, secured to the plate 236 by a pair of studs 248 which are pressed by a spring 270 into selected pairs of five depressions 234, Fig. 18, in a live metal plate 232 carried by a fixed insulating plate 230. The live contactstud 252 co-operates selectively with three contact-studs such as 256, 258, 260 leading through further automatic switch mechanism described below, respectively to the three solenoid-valves of the motors controlling the gear. In order to prevent accidental movement into reverse, the gate-slot of the latter is of reduced width, and the preselector switch-arm 274 has to be retracted against a spring 326 so that its reduced lower diameter enters the slot. A modified preselector switch shown diagrammatically at 332, Fig. 25, and completely in Figs. 30-32 (not shown), comprises a lever arm 338, secured to a sliding bar 340 carrying a cam swell, arranged to close contacts 350, 354 on either side of the cam, when the bar is rocked, an end contact 346, for the solenoid valve of the selector motor 34, being closed by inward longitudinal movement of the bar as before. In this construction, circuit is broken at the end of a change, prior to clutch-engagements, simply by release of the lever, which springs to the central position. In the previous construction, for breaking the solenoid circuit at the end of a change and preparing the circuit for the next change, prior to clutch engagement, there is provided automatic switch mechanism comprising a contact-member 610, Fig. 37, having slotted engagement with the gear shifter lever 504 so as to be moved with the latter only in its longitudinal gear-establishing or neutralizing movements. The member 610 carries a pair of contact-strips 604, 606, Fig. 38, which, in the neutral position, bridge respectively fixed contacts 594, 596 and 598, 600, the former, 594, 598, leading respectively to the two solenoid valves 572, 574 of the striking motor 500 and the latter 596, 600 to the preselector switch-contacts 256, 260. The arrangement is such that, just before the shifter-lever 504 reaches its final gear-engaged position, the corresponding contact-strip 604 or 606 slides off the end of its contact 594 or 598 thus breaking the circuit of the operative solenoid-valve and cutting off the current, whilst the other contact-strip remains in bridging contact and keeps the circuit of the opposite solenoid-valve complete ready for the next change in the opposite direction. For neutralizing the gear there is a central contact 602, leading to the central contact-stud 259 of the preselector switch and adapted, in gear-engaged positions, to complete the circuit through a contactstrip 604 or 606 to the solenoid-contact 594 or 598 of the gear-establishing motor opposite to that which has engaged the previous gear, whereby when the preselector switch is moved to neutral and the current rendered operative, the gear will be moved to neutral position, and just before reaching such position the energizing contact-strip 604 or 606 will slide clear of the contact 602 and break the circuit. Fig. 25 shows a modified form of automatic switch provided only for neutralizing the gear and comprising a cam bar 349, operated by the gearestablishing motor 24 and co-operating with spring-loaded pins, the outer pair 356, of which are adapted to close contacts 360, 374 leading directly to the respective solenoid-valves 192, 194 of the gear-establishing motor 24, whilst the inner pin 366 closes a contact 368 leading to the battery 335. The manual preselector switch 332 is connected directly to the gear establishing solenoid-valves 192, 194 and to the cross-shift solenoid-valve 214 and the arrangement is such that, as soon as the cam bar 349 begins to move in either direction under the influence of the gear-establishing motor 24, it closes contacts 368 and the contact 360 or 374 to energize the solenoid-valve opposite to that which is producing movement of the motor. Such energization has, however, no effect on the continuance of the shift since in this construction the armatures of the solenoid-valves 192, 194 are integrally connected and the one which commences to move first has the major effect. At the end of the gearestablishing movement, the central pin 366 falls into one of the outer recesses 359 of the cam bar and breaks the circuit connecting the inoperative solenoid-valve to the battery. The purpose of this arrangement is to provide for rapid neutralizing which is accomplished by flicking the preselector-lever momentarily in the appropriate backward or forward direction, to initiate movement of the cam bar 349 which then remakes the battery contact 368 and energizes the gear-establishing solenoid-valve 192 or 194 which was not previously operative, whereupon the gear is neutralized, circuit being again broken in neutral by the pin 366. Fig. 25 also shows means whereby release of the accelerator pedal 421 and the decay of enginesuction at 14, consequent on stoppage of the engine, close series contacts 410, 412 which shunt the automatic switch-contact 368 and supply current through contacts 360 or 374 to an appropriate solenoid for neutralizing the gear. In Figs. 26-28 (not shown), the suctioninfluenced switch 410 is mechanically interlocked with the accelerator pedal instead of electrically as shown. To facilitate this neutralizing operation after stoppage of the engine, the operative suction is derived from a vacuum storage-tank 94, Figs. 1 and 25, connected to the engine induction-pipe 14 through a non-return valve 100. Stop-cocks 102, 104, Fig. 1, permit selection of either the s