| 摘要 |
<p>1,179,426. Change-speed control. CLAYTON DEWANDRE CO. Ltd. 16 April, 1968 [20 April, 1967], No. 18278/67. Heading F2D. A vehicle change-speed gear control comprises a shift-lever 10 mounted on a pin 11 in an inverted trunnion 12 and movable along a gate 9 to pivot the trunnion 12 about pins 13, 14 so that cams 21, 22 on the trunnion co-operate with pistons 15, 16 through rollers 19 to open valves 25, 26 to direct compressed air to a gear selector motor (50), Fig. 5 (not shown), the lever 10 being also pivotable about the pin 11 to move across the gate 9 to rock a hollow shaft 35 carrying arms 64 co-operating with pistons (65), Fig. 4 (not shown), to open valves (66) to direct compressed air to a gear shift motor (70), Fig. 6 (not shown), such rocking of the shaft 35 being prevented by pistons (41), (42), Fig. 3 (not shown), co-operating with lugs (38), (39), on the shaft (35) until the compressed air operated main clutch is disengaged, when the pistons are withdrawn. As shown, the control is for an eight forward speed and reverse gear, and a third piston 17 is controlled by a cam 23 to open a valve 27 to direct compressed air to a dual-range cylinder (not further described), to obtain the top four ratios. A fourth spring loaded piston 18 co-operating with cam 24 provides a delay between selection of fourth and fifth gears. A collar 77 or lever 10 must be raised to avoid a baulk on the gate 9 to obtain reverse. A further pair of arms (67), Fig. 4 (not shown), on shaft 35 co-operate with a pair of pistons (68) loaded upwards against the arms by springs and by air pressure communicated through one-way valves (71), (72) in the shift motor (70) from the pistons (66). Rocking of shaft 35, after the clutch is disengaged, is therefore resisted by springs and air pressure until the split piston (73), (74) in the shift motor reaches either of its end positions, i.e. the gear is engaged, when it abuts and opens the respective one-way valve to release the air pressure acting on the respective piston (68) to allow the other piston (68) to hold the lever 10 in its engaged position.</p> |
