Gear change mechanism
AssigneeProdrive Engineering Limited
InventorRoland James Broadbent
Life of this patent
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Abstract
An improved gear change mechanism is provided for semi-automatically selecting a change up or change down gear change. The mechanism includes a shaft (31) which is movable in its axial direction and about its axis to make one such movement or a combination of such movements according to the gear to be selected. The shaft (31) is moved by pistons (36, 37) coaxial with the shaft for the axial movement and a piston (46) at a right angle to the shaft for the rotational movement. In practice the axial movement is a translating movement and the rotary movement is a movement into and out of engagement with the gears. Throttle and clutch control functions are also provided so that a gear change is initiated and brought about by switches (19A and 19B).
Claims16
A gear change mechanism for a gearbox (13, 35) which comprises a drive assembly (11, 12), a gearbox selector (33) connectable to the drive assembly, an actuator (19A, 19B, 19C, 19D) for actuating the drive assembly;
- and
- control (17) means for controlling the operation of the drive assembly according to instructions received from the actuator and according to programming of the control means;
- the drive assembly including:
- a shaft (31) drivingly connectable to the gearbox selector (33), the shaft being movable in its axial direction and about its axis to move a plurality of positions according to the gear to be selected in the gearbox (35) and a neutral gear position;
- a first piston assembly (36-43) wherein the shaft (31) is operatively driven in its axial direction by the first piston assembly which is coaxial with the shaft, pressure fluid being applied selectively to the first piston assembly to move the shaft in the axial direction;
- the first piston assembly comprising a pair of collars (42, 43) acting as first abutment means restricting the axial movement of the shaft (31) and a pair of annular pistons (36, 37) located about the shaft and each piston is movable selectively towards a gear engaging position and towards a neutral gear position;
- a cylinder (40) comprising a pair of recesses (41) located at opposite ends of the cylinder (40) walls to engage with the collars (42, 43);
- second abutment means (39) carried by the cylinder (40), the movement of each piston (36, 37) towards a neutral gear position being limited by the second abutment means (39), and during said movement each piston (36, 37) is engageable with the second abutment means (39) which is located between the pistons, and pressure fluid being applied to opposite sides of the pistons to urge the pistons towards the neutral gear position, the first abutment means (42, 43) acting upon movement in the gear engaging direction.
Dependencies are inferred from the claim text.