Clutch control system in which the clutch actuation is initiated by control of the gear shift lever

A transmission for a motor vehicle, said transmission comprising,

• a change speed gearbox (12) comprising at least first and second rotatable shafts (21, 22), said second shaft (22) being the output shaft, a plurality of rotatable gear ratios each being de-selectable and each being mutually exclusively selectable for transmitting rotary motion between said shafts (21, 22) through each selected one of said gear ratios, and gear ratio selection means including a gear lever (16) which is manually movable to cause de-selection of any previously selected gear ratio and to cause selection of any desired said gear ratio, and
• clutch means (14) connected with the first shaft (21) and intended for interposing between the said engine (10) and said first shaft (21), the clutch means (14) being engageable to transmit rotary motion between the said engine (10) and first shaft (21) and disengageable to interrupt that transmission,
• clutch control means (18, 20) to automatically engage and disengage said clutch means (14), said clutch control means (18, 20) comprising first observing means (52) to observe when any said gear ratio is selected, said gear level (16) having a first part (33) and a second part (40) mounted on the first part (33) and being movable with said first part (33) in response to manual force applied to the second part (40) for transmission to said first part (33), said gear ratios being divided into at least first and second divisions, the first division comprising at least one but not all of said gear ratios and the second division comprising at least one remaining said gear ratio, the first part (33) of the gear lever (16) having limits of movement (48, 50) in first and second opposite directions (A, B) comprising first and second gear shift limit positions (48, 50) which are spaced apart and fixed such that movement of the first part (33) of the gear lever (16) in the first direction (a) is away from the second limit position (50) and towards the first limit position (48) and movement of said first part (33) in the second direction (B) is away from the first limit position (48) and towards the second limit position (50), the first and second divisions being correlated to the first and second limit positions respectively such that movement of the first part (33) of the gear level (16) in said first direction (A) into said first limit position (48) causes selection of a said gear ratio in said first division and movement of said first part (33) in said second division (B) into said second limit position (50) causes selection of said gear ratio in the second division, resilient means (46) acting on the second part (40) of the gear lever to return said second part to a pre-determined initial position relative to said first part (33) when no manual force is applied to said second part (40), said second part (40) being movable to a limited extent relative to the first part (33) in each of two opposite directions (a, b) from said initial position when a force is applied to the second part (40) and wherein one (a) of those two opposite directions (a, b) is in said first direction (A) and the other (b) of those two opposite directions (a, b) is in said second direction (B), and
• second observing means (58, 60, 62) to observe movement of the second part (40) of the gear lever (16) relative to the first part (33) in said first (A) and second (B) direction respectively,
• said clutch control means (18, 20) being so arranged that, when the first part (33) of the gear lever (16) is in a said limit position (48, 50) so that a said ratio in the division correlated to that limit position (48, 50) is in a selected state, movement of said second part (40) relative to the first part (33) in a said direction (A, B) toward the other limit position (48, 50) is observed by said second observing means (58, 60, 62) causing the clutch control means (18, 20) to cause automatic disengagement of the clutch means (14), said clutch control means (18, 20) being further arranged such that subsequent to a de-selection of a said gear ratio the next selection of a said gear ratio observed by said first observing means (52) causes said clutch control means (18, 20) to automatically engage said clutch means (14),
• said clutch control means (18, 20) further comprising a memory arrangement (68) for memorizing in which of said first or said second direction (A, B) the first part (33) of said gear lever (16) was moved into the first or second limit positions (48, 50) respectively to cause the selection of the gear ratio currently in the selected state, and said control means (18, 20) being responsive to said memory arrangement (68) such that said control means (18, 20) inhibits disengagement of said clutch means (14) whilst said gear ratio remains in said currently selected state and the second part (40) of the gear lever (16) is moved in the memorized direction (A, B) relative to the first part (33).