GB403422A - Improvements in and relating to variable transmission gear - Google Patents

Abstract

403,422. Change-speed gearing. MARTINUZZI, P. F., King's Ride, Sheen Road, Richmond, Surrey. June 20, 1932, Nos. 17385/32, 18092/32, and 7446/33. [Class 80 (ii).] Change-speed gearing suitable for vehicles comprises a first change-speed gearing A, Fig. 1, adjacent a driving engine or clutch 14 and a second change-speed gearing B further therefrom, the second gearing B being of an " easy-change " type and being arranged to be always in neutral when gear change is taking plaec in the first gearing A. " Easy-change " type here means operated by a pair of friction clutches 32 as shown, or by synchronized claw clutches, or by brakes as in eipicyclic gearing, or by other means allowing slip to eliminate shock in changing. Each of the gearings A, B yields two speeds, their countershafts 25, 23 being separate, so that the combined arrangement yields four speeds. If the gearing B were operated by a lever 137, Fig. 9, it would be fore and aft displacements of a lever 141 in a gate 160 that would make the changes. If the gearing A were operated by a lever 138, it would be displacements transverse in the gate that would affect it, and during such transverse displacements the gearing B would necessarily be in neutral. The length of the combined arrangement may be reduced by such means as is shown in Fig. 2 in which power passes from a gear 51 to a gear 46 during the reduced drive in gearing A and from the gear 46 to the gear 51 during the reduced drive in gearing B, the pair 46, 51 and a countershaft 50 being common to the two. Other speeds are a direct drive and a drive through a train 43, 53, 52, 49. The gearing A comprises a pair of sliding constant-mesh helical gears 43, 53 with dog faces at 44 and 54. In Fig. 3 is shown another combined arrangement with a pair 74, 69 common to both gearings A and B. The gears 74, 69 have helical teeth so inclined that the gear 74 is pressed against the end of a driving- shaft 60 when the gear 74 drives, and against a collar 165 on a driven shaft 65 when the gear 74 is driven. A double claw clutch 87 in the gearing B is synchronized by a double-ended frictionclutch sleeve like that described in Specification 342,824. The clutch 87 is connected to a selector 90, Fig. 7. The gearing A is operated by a pair of coupled clutch sleeves 73, 77 connected to a selector 80. The lower end 1001 of a ball lever 100 engages a fork 102 on a bell-crank lever 103 the other arm of which engages the selector 80 at 104, Fig. 7. A boss 107 on the lever 100 engages a transverse slot in a bracket 106 fast on the selector 90. The lever 100 is guided in a gate 108 and it is apparent that movement of the boss 107 up and down of Fig. 7 to operate the selector 80 of the gearing A is only possible when the selector 90 of the gearing B is neutral. There are four slot ends 1, 2, 3, 4 for forward speeds, as is usual, and a branch slot 110 for reverse. For the lever 100 to move into the reverse slot 110, its lower end 100<1> must first disengage the fork 102 on the bell crank 103. Continued movement effects engagement with a slot 196- on a selector 97 which slides a reversing idler 93, Fig. 3. A servo control device using fluid pressure or suction is described in which rods 135, 136, Fig. 9, operate slide valves admitting to four cylinders the pistons of which are connected to the horizontal arms of T-levers 132, 133. The vertical arms of these levers operate the gear-changing clutches. An engine clutch pedal when depressed turns a cock admitting the fluid medium and so effecting a preselected change. Alternatively, links 139, 140, Fig. 9, operating the servo device may be controlled by a suitable arrangement of cams operated by a selector lever instead of by the gate device shown, and such selector lever may be controlled by any known system of automatic gear change with means for opening the main clutch during speed changing. Specifications 339,694, [Class 80 (ii), Gearing, Variablespeed &c.], 350,334, 355,533, and 358,674 are referred to as showing synchronized claw clutches in change-speed gearing, and Specifications 290,310, [Class 80 (ii), Gearing, Variablespeed &c.], and 366,081 as showing isolating clutches for facilitating gear changing.