GB394093A - Change-speed gear mechanism - Google Patents

Abstract

394,093. Facilitating changing speed. RILEY, P., Castle Works, Aldbourne Road, Coventry. March 23, 1932, No. 8629. [Class 80 (ii).] In change-speed gearing suitable for vehicles of the type having sliding toothed members such as gears 32, 33 or dog clutches 34, 35, noiselessness in the change is effected by auxiliary ratio gearing on two dummy shafts 2, 5 controlled by fluid-pressure means. The gearing shown is as described in Specification 376,535 and the dummy shafts 2, 5 are extensions of the driven shaft 3 and of the counter-shaft 6 respectively. The auxiliary gearing comprises pairs of loose constant-mesh gears 7 .. 10 which are entrained by being thrust by pressure oil against collars 11 fast on the shafts. A source of pressure oil 38 is cut off from supply by a master valve (not shown), except when the engine clutch is disengaged. To put in first gear, a control selector lever 15 moves a selector bar 21 to the right. This first brings a port 37 to connect a port 23 to pressure oil which is delivered to two pipes 41, 42. The gears on the shaft 2 of the two pairs 7, 9 are both clutched to the shaft 2, while the other gear of the pair 7 on the shaft 5 is clutched to that shaft. The pair 7 is therefore operative to bring the teeth of the transmission gears 32 to proper speed for engagement. Lost motion at 22 between the rod 21 and a slider 20 carrying a fork 17 is thus taken up and the gears are enmeshed. Continued movement of the rod 21 brings an exhaust groove 44 over the port 23 so as to disconnect the auxiliary drive. Tappets 31 on the back of the rod 21 through a rocking lever 28 lock and unlock the slider 20 as required. Movement of the rod 21 to the left for second speed connects to oil a port 24 and pipes 46, 47. To the shaft 5 are clutched the two gears thereon of the pairs 8, 9 and to the shaft 2 are clutched two gears of the pairs 8, 10, so that the pair 8 is operative to time the transmission gears 33, while a groove 50 disconnects the auxiliary train on completion of the stroke. On sliding another selector rod (not shown), to the right for third speed, oil passes from a port 25 to pipes 41, 47 to render operative the auxiliary pair 9. Sliding to the left for direct drive connects to oil a port 26 and pipes 46, 49 to render operative the pair 10 which corresponds in ratio to a transmission constantmesh pair 36. Specification 257,413, [Class 80 (ii), Gearing, Variable-speed &c.], and 392,330 are referred to in the Provisional Specification.