Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
177 words
A gearbox comprising a selector rod (3) which is movable in order to select a gear ratio, actuating means (6, 9) for moving the selector rod (3), the actuating means acting on the selector rod in at least one direction of movement via resilient means (7, 8, 10) which is arranged to store the energy of the actuating means (6, 9) when the actuating means is operated but the selector rod (3) is not free to move in that direction of movement, the rod being moved by the energised resilient means (7, 8, 10) when it becomes free, characterized in that the gearbox is a constant mesh gearbox having pairs of gears (1a, 2a to 1f,2f) on parallel shafts (1, 2) in constant mesh with each other, and in that the selector rod (3) is movable in an axial direction and in a rotational direction about its axis to select the gears, and the actuating means (6, 9) acts via the resilient means (7, 8, 10) for both axial and rotational movements of the selector rod (3).
Claim 2
Dependent Claim
40 words
A gearbox as claimed in claim 1, in which the resilient means comprises separate spring means (7, 8 and 10) via which the actuating means (6 and 9) operates for axial movements and rotational movements of the selector rod (3).
Claim 3
Dependent Claim
55 words
A gearbox as claimed in claim 2, in which the spring means (8) via which the actuating means (6) operates for movements of the selector rod (3) corresponding to gear engagement and disengagement from and to neutral is dual rate, providing an increased rate of resistance after it has been deflected over a certain travel.
Claim 4
Dependent Claim
37 words
A gearbox as claimed in claim 3, in which the actuating means (6) includes an electric motor (6) for axial movement of the selector rod and an irreversible reduction gear (11) through which the motor (6) operates.
Claim 5
Dependent Claim
36 words
A gearbox as claimed in any preceding claim, in which the selector rod (3) or a coaxial extension (4) thereof is coupled to a transverse arm (21, 28), for effecting rotational movement of the selector rod.
Claim 6
Dependent Claim
45 words
A gearbox as claimed in claim 5, in which the spring means via which the actuating means (9) operates for rotational movement of the selector rod (3) includes a Belleville spring (10) arranged between two coaxial parts (21, 28) which together form the transverse arm.
Claim 7
Dependent Claim
28 words
A gearbox as claimed in claim 5 or claim 6, in which the actuating means includes an electric motor (9) for rotational movement of the selector rod (3).
Claim 8
Dependent Claim
30 words
A gearbox as claimed in any one of claims 1 to 3, in which the actuating means includes an hydraulic motor for axial and/or rotational movement of the selector rod.
Claim 9
Dependent Claim
23 words
A gearbox as claimed in claim 4 or claim 7, in which a brake is applied to a shaft of the electric motor.
Claim 10
Dependent Claim
20 words
A gearbox as claimed in claim 7, in which the electric motor (9) operates via an irreversible reduction gear (23).
Claim 11
Dependent Claim
22 words
A gearbox as claimed in any one of claims 1 to 10, in which the resilient means (7, 8, 10) is pre-loaded.
Claim 12
Dependent Claim
18 words
An automatic transmission including a constant mesh gearbox as claimed in any one of claims 1 to 11.
Claim 13
Independent Claim
89 words
A method of operating an automatic transmission employing a constant mesh gearbox as claimed in any one of claims 1 to 12, in which the actuating means (6) is operated to urge the selector rod (3) in a direction corresponding to gear disengagement to neutral while torque is being transmitted through the gearbox, and the actuating means (9) is operated to urge the selector rod (3) in a direction between neutral positions before movement of the selector rod (3) for disengagement of a gear from neutral has been completed.