| 摘要 |
463,684. Change speed gearing. GENERAL MOTORS CORPORATION. Oct. 3, 1935, No. 34533/36. Convention date, Oct. 8, 1934. Divided out of 463,643. [Class 80 (ii)] Change-speed gearing for vehicles comprises three units in series, one R, Fig. 4, for selecting neutral, forward, or reverse drive, another unit M under manual control for a change of driving- ratio, and a further unit A for effecting a change of ratio under the control of a speed-responsive device or governor 211, Fig. 18, there being a unitary control means or lever 232, Fig. 1a, on the steering column for the reverse and manual units. The description is the same as in Specification 463,643. The units M and A in the arrangement shown are planetary and controlled by alternative plate clutches and wrapping band brakes. The unit M has stepped planets 71, 72, Fig. 4, connecting an intermediate shaft 32 to a driven shaft 64. This unit is in low speed with the brake 74 applied unless a slide valve 140<1>, Fig. 18, has been shot over to the left from the position shown so that pressure oil entering at 136 can pass up a duct 1451 and along another 1431 to depress a piston 1381, Fig. 10, and so release the brake 74, Fig. 4, and engage clutch packs 46a, 46b so that the unit M turns solid on high speed. The valve 140<1>, Fig. 18, is opened, and normally held open for low speed by a spring 1641 acting on a toggle 157<1>, 158<1>, the fixed pivot of which is at 156<1>. To change the unit M to high, a lever 192 is rotated clockwise about its pivot shaft 186 so as to extend the bias spring 1641 until a toggle spring 160<1> effects the quickthrow-over of the valve. The turning of the pivot shaft 186 is done by pulling a rod 190 left of Fig. 10. That is, to change up in the unit M a rod 225 is pulled left of Fig. 10 and upwards of Fig. 1a. The changing of the unit M is between points " High " and " Low " of a quadrant 235<1>, corresponding to the movement of a bowl lever 250, Fig. 10, upwards from the position shown and with lost motion clear of a fork 254 for operating the reverse unit R. To bring in reversed drive, the lever 232 is moved to position "REV," Fig. 1a, which brings the bowl 251 from the neutral position shown in Fig. 10 down to position 251<11>, and owing to a lever 226 passing over a dead centre, the pivot control shaft 186 of the unit M is not then operated. When the hand lever 232 is moved onto position " 3rd," Fig. 1a, an over-riding downshift in the unit A is imposed as described in the Specification referred to, this unit being normally controlled by the governor 211, Fig. 18, acting at one fulcrum 169 of a floating lever 166 and by the accelerator (not shown), acting at another fulcrum 175 so as jointly to control the valve 140 of the servomotor 138 of the unit A. A booster valve is described with reference to Figs. 15-17 (not shown), to prevent the wrapping brakes 74, 42 of the units M and A from being unwound during the reversed drive. |
