Shift control

Claim 2

A semi-automatic, multi-ratio transmission having at least three power paths defining low, intermediate and high speed ratios, the improvement comprising: speed sensitive controlling means for controlling the automatic shifting of said transmission, said controlling means including first control means for effecting automatic shifting of said transmission only in an upshift direction and second control means for effecting automatic shifting of said transmission only in a downshift direction; operator controllable selector means coacting with said first and second control means for determining the direction of automatic shifting; and holding means for preventing downshifting of said transmission when said first control means is activated and for preventing upshifting of said transmission when said second control means is activated.

Claim 3

A transmission according to claim 1, wherein said controlling means includes neutral control means for placing the transmission in a non-power transmitting condition; and said operator controllable sElector means including a neutral position for activating said neutral control means, said operator controllable selector means including a manually movable selector member mounted for movement in one direction away from said neutral position for controlling upshifting and movable in the opposite direction toward said neutral position for controlling downshifting.

Claim 4

A transmission according to claim 2, wherein said selector means automatically activates said first control means when said selector member is moved in said one direction and automatically activates said second control means when said selector member is moved in said opposite direction.

Claim 5

A transmission according to claim 1, wherein said operator controllable selector means includes a manually movable selector member which can be movable in either an upshift or a downshift direction for positioning said transmission in a selected speed ratio; said first control means including upshift circuitry means activated by said selector means when said selector member is moved in said upshift direction for permitting upshifting of said transmission to take place automatically until the ratio selected by the operator has been reached; said second control means including downshift circuitry means activated by said selector means when said selector member is moved in a downshift direction for permitting automatic shifting of said transmission in a downshift direction until the ratio selected by the operator has been reached; and said holding means including holding circuitry means coacting with said upshift and downshift circuitry means for preventing downshifting when said upshift circuitry means is energized and for preventing upshifting when said downshift circuitry means is energized.

Claim 6

A transmission according to claim 4, wherein said controlling means includes speed sensing means associated with said upshift and downshift circuitry means for controlling the automatic shifting between the various speed ratios.

Claim 7

A transmission according to claim 4, wherein said transmission includes first, second and third clutch means associated with said low, intermediate and high speed ratios, respectively; said controlling means including first, second and third electrical relay means for controlling the energization of said first, second and third clutch means, respectively; speed sensing means coacting with said first, second and third relay means for controlling the progressive energization thereof, said speed sensing means including first responsive means for permitting energization of said first relay means whenever the speed is below a first predetermined maximum, second responsive means for permitting energization of said second relay whenever the speed is below a second predetermined maximum which is greater than said first predetermined maximum, and third responsive means for permitting energization of said third relay means whenever the speed exceeds said second determined maximum; and said holding circuitry means maintaining whichever one of said first, second and third relay means is energized in its energized state even though the vehicle speed may change in the direction opposite to the selected shift direction and falls within the speed range of a different electrical relay means.

Claim 8

A control system for a vehicle transmission having at least three selectible forward speed ratios, comprising: a plurality of circuitry means each associated with a respective speed ratio for effecting automatic shifting of said transmission into the respective speed ratio; speed responsive means for sensing vehicle speed and for energizing one of said circuitry means corresponding to the vehicle speed, said speed responsive means including speed controlling means associated with each of said circuitry means for activating same and effecting automatic shifting of said transmission in response to the vehicle obtaining a preselected speed; manually movable selector means for permitting said transmission to be selectively disposed in either an upshift or a downshift mode of operation; upshift circuit means actuated by said manually movable selector means when same is moved in said upshift direction for permitting automatic upshifting of said transmission until reaching the preselected speed ratio selected by said selector means, said upshift circuit means including control means associated with said plurality of circuitry means for permitting automatic upshifting of said transmission until reaching said preselected speed ratio; and energy interrupting means associated with said plurality of circuitry means for permitting automatic upshifting of said transmission from one speed ratio into the next successive speed ratio in response to increases in vehicle speed while preventing automatic downshifting of said transmission irrespective of decreases in vehicle speed.

Claim 9

A control system for a vehicle transmission having at least three selectible forward speed ratios, comprising: a plurality of circuitry means each associated with a respective speed ratio for effecting automatic shifting of said transmission into the respective speed ratio; speed responsive means for sensing vehicle speed and for energizing one of said circuitry means corresponding to the vehicle speed, said speed responsive means including speed controlling means associated with each of said circuitry means for activating same and effecting automatic shifting of said transmission in response to the vehicle obtaining a preselected speed; manually movable selector means for permitting said transmission to be selectively disposed in either an upshift or a downshift mode of operation; upshift circuit means actuated by said manually movable selector means when same is moved in said upshift direction for permitting automatic upshifting of said transmission until reaching the preselected speed ratio selected by said selector means, said upshift circuit means including control means associated with said plurality of circuitry means for permitting automatic upshifting of said transmission until reaching said preselected speed ratio; and energy interrupting means associated with said plurality of circuitry means for permitting automatic upshifting of said transmission from one speed ratio into the next successive speed ratio in response to increases in vehicle speed while preventing automatic downshifting of said transmission irrespective of decreases in vehicle speed.

Claim 10

A control system according to claim 7, further including downshift circuit means energized by said selector means when moved in said downshift direction for permitting automatic downshifting of said transmission in response to decreases in vehicle speed until said transmission reaches the preselected speed ratio determined by said selector means, said downshift circuit means including second control means associated with said plurality of circuitry means for permitting sequential energization thereof for causing the transmission to be downshifted sequentially through the speed ratios in response to decreases in vehicle speed; and second energy interrupting means associated with said plurality of circuitry means for permitting sequential and automatic downshifting of said transmission toward said selected speed ratio as said vehicle speed decreases while preventing upshifting of said transmission irrespective of increases in vehicle speed.

Claim 11

A control system according to claim 8, including neutral circuit means energized by said selector means when same is disposed in a neutral position for placing said transmission in a non-power transmitting condition.

Claim 12

A control system according to claim 9, wherein said speed responsive means includes a plurality of normally open speed responsive switches with one of said speed responsive switches being associated with each of said circuitry means for permitting energization thereof when the vehicle speed is in a preselected range.

Claim 13

A control system according to claim 9, wherein said upshift circuit means includes upshift electrical relay means which is energized only when said selector means is moved in an upshift direction, and said downshift circuit means including downshift electrical relay means which is energized only when said selector means is moved in a downshift direction, each of said electrical relay means having normally opened relay switches associated with several of said plurality of circuitry means for controlling the energization thereof, the relay switches associated with the upshift and downshift relay means and as associated with each circuitry means being connected in parallel with one another.

Claim 14

A control system according to claim 9, wherein each circuitry means includes electrical means which, when energized, controls a clutch for effecting shifting of said transmission into a selected speed ratio.