720,210. Change-speed gear. AKT.-GES. FUR UNTERNEHMUNGER DER EISEN-UND STAHLINDUSTRIE. April 18, 1952 [April 20, 1951]. No. 9828/52. Class 80 (2). On a rail vehicle a non-reversible engine drives an output shaft 9, carrying the bevel pinion 53 of a reverse-gear (not shown), through a hydrodynamic torque-converter 2 (not described) having blades adjusted progressively between idle and full turbine speed positions, B, A, by a lever 3; and a two-speed gear wherein freely-mounted wheels 5, 7 meshing wheels 6, 8, fast on the output shaft 9, are selectively connected to the turbine shaft 4 of the torque-converter by clutches 11, 12, one or both. of which have synchronizing and balk means. The clutches 11, 12 may, as shown, be one-way with faciallyinclined jaws on a sleeve 10 splined on the turbine shaft 4, or two-way clutches. Initially the lowspeed clutch 12 is engaged by first raising a clutch shift handle 17 to free a spring-loaded lock-peg 36 from an apertured fixed plate 34, then moving the handle to the extreme left and freeing it to allow the lock-peg to engage a low-speed lockhole 37. At this time the torque-converter is idling, its blade-set lever 3 having been moved to idle by depressing a manual lever 48 to idle position B. The clutch-shift handle 17 is secured to a frame 59, which, during the leftward movement, acts through a spring 15 on a clutch-shift lever 13, pivoted at 75, to engage the slow-speed clutch 12. The frame 59 also takes along a cam 39, whilst the clutch-shift lever 13 takes along, through a spring connection 44, a cam 45, until the slant side 41 of the cam 39 and a lockshoulder 47 of the cam 45 both lie at the left of a roller 51 on a rod 19 connected to the blade-set lever 3, whereby when the operator subsequently moves the converter-control lever 48 to the full turbine speed position A, a spring 49 is able to raise the rod 19 setting the blade-lever 3 to drive. A balk-synchronized upshift is made by placing the clutch-shift handle. 17 in its rightward position, shown, with the lock-peg 36 engaging the highspeed, hole 38, no other action being required of the operator. The first effect of this is to load the clutch-shift lever 13 rightwards through a spring 16 and at the .same time to move the cam 39 rightwards whereby its slant side 41 depresses the roller 51 thus idling the converter, position B. Tooth-pressure in the low-speed clutch 12 is thereby relieved and the spring 16 moves the clutch-shift lever 13 to a central position (shown), taking along the cam 45, the undersurface 42<SP>1</SP> of which maintains the idle-set position of the converter. The clutch-sleeve 10 is temporarily arrested in this central position, preventing contact between the teeth of the high-speed clutch 11, by engagement of friction surfaces 26, 24, the former on the wheel 7, the latter on a sleeve 23, helix-mounted at 22 on the clutch-sleeve 10 and, during the preceding engagement of the low-speed clutch, being in contact with a brake-surface 27 whereby it was maintained screwed to an extreme rightward position on the clutch-sleeve 10. The control-lever spring 16 now loads the friction surfaces 24; 26 as well as further brake surfaces 32 on the clutchsleeve 10, whereby braking action is applied to the clutch sleeve by. the lever f3 and to the helix sleeve 23 by the more slowly running wheel 7, and thence to the turbine shaft 4 until the speed of the latter is less than that of the wheel 7, whereupon the helix sleeve 23 screws leftwards, permitting the toothed clutch I to engage. The final movement takes, along the shift-lever 13 which becomes locked in the high speed position by the lock-peg 36 springing into an opening 52 in the end. of the lever, and at the same time causing the lock-cam 45 to release the roller 51, whereupon the spring 49 returns the blade-set lever 3 to the full turbine speed position A and the upshift to high-speed is complete. Downshift is similar except that no balk or braking action occurs, the engagement of 'the low-speed clutch 12 taking place as soon as the drag-torque of the idled converter has accelerated the turbine shaft 4 to synchronous speed. In Fig. 2 (not shown), the balk and synchronizing surface, instead of being carried as at. 26, Fig. 1, on the high-speed wheel 7, is on a separate wheel geared to the output shaft to rotate slightly faster than the wheel 7 to ensure complete engagement of the high-speed clutch teeth 11. The leveroperated braking surface 32 is also replaced by a friction clutch which directly brakes the turbine shaft 4 from the high-speed wheel 7 on initialupshift movement of the clutch-shift lever 13.. A cone clutch is provided for synchronizing the lowspeed clutch 12 and is engaged through springs by the initial, downshift movement of the clutchshift lever. To make a shift up or down, the operator must first set the converter blade-control to idle, which action also sets the engine fuelcontrol to the half position, both these controls requiring separate manual resetting after the shift. The same converter-idling movement also releases the clutch-shift linkage, which latter, in the drive position, is locked by entry of the converter-control rod into one of two holes defining high and low speed positions of the clutch linkage. A ramp between these holes permits part advance movement of the converter control to full turbine speed position after passing neutral on the way to high speed, to facilitate clutch engagement. In Fig. 4 the low-speed dog clutch 70, which need not necessarily have overrun-type teeth, has a balk synchronizer comprising a clutch having discs 124 connected alternately to the driven wheel 5 and to a sleeve 123 helix-mounted on the driving clutch-sleeve 10 splined on the turbine shaft 4. Clutch engagement is effected by leftward movement of a control collar 76 integral with the clutch-sleeve 10 and carrying a cone 128 which acts through levers 127 and springs 126 to engage the friction clutch first. A shoulder on the helix sleeve 123 then prevents further leftward movement of the clutch-sleeve 10 to engage the positive clutch 70 unless the turbine-shaft 4 and with it the clutch-sleeve 10 are rotating more slowly than the low-speed wheel 5.