Hydrostatic-differential transmission

Claim 2

A hydromechanical transmission, comprising: an input shaft, an output shaft, two power paths between the input shaft and the output shaft including a mechanical path and a hydraulic path, said hydraulic path including a variable speed hydraulic transmission, a differential unit for combining power from said mechanical path and said hydraulic path including a first gear, clutch means selectively drivingly connecting said first gear to the input shaft and defining the mechanical path, a second gear drivingly connected to the hydraulic transmission, a third gear drivingly connected to said output shaft, means for selectively fixing the speed ratio between said first, second and third gears, control means for providing a low speed range and a high speed range including means for actuating said clutch means and deactuating said speed ratio fixing means to transmit power hydromechanically through both paths from the input shaft to the output shaft in the low speed range, and means for deactuating said clutch and actuating said speed ratio fixing means to transmit all power hydraulically from the input shaft to the output shaft in the high speed range, said control means including means for varying the hydraulic transmission ratio to reduce the speed of the output shaft to zero in both the high and low speed ranges.

Claim 3

A hydromechanical transmission, comprising: an input shaft, an output shaft, two power paths between the input shaft and the output shaft including a mechanical path and a hydraulic path, said hydraulic path including a variable speed hydraulic transmission, a differential unit for combining power from said mechanical path and said hydraulic path including a first gear, clutch means selectively drivingly connecting said first gear to the input shaft and defining the mechanical path, a second gear drivingly connected to the hydraulic transmission, a third gear drivingly connected to said output shaft, means for selectively fixing the speed ratio between said first, second and third gears, control means for providing a low speed range and a high speed range including means for actuating said clutch means and deactuating said speed ratio fixing means to transmit power hydromechanically through both paths from the input shaft to the output shaft in the low speed range, and means for deactuating said clutch and actuating said speed ratio fixing means to transmit all power hydraulically from the input shaft to the output shaft in the high speed range, said control means including means for varying the hydraulic transmission ratio to reduce the speed of the output shaft to zero in both the high and low speed ranges.

Claim 4

A hydromechanical transmission, comprising: an input shaft, an output shaft, two power paths between the input shaft and the output shaft including a mechanical path and a hydraulic path, said hydraulic path including a variable speed hydraulic transmission, a differential unit for combining power from said mechanical path and said hydraulic path including a first gear, clutch means selectively drivingly connecting said first gear to the input shaft and defining the mechanical path, a second gear drivingly connected to the hydraulic transmission, a third gear drivingly connected to said output shaft, means for selectively fixing the speed ratio between said first, second and third gears, control means for providing a low speed range and a high speed range including means for actuating said clutch means and deactuating said speed ratio fixing means to transmit power hydromechanically through both paths from the input shaft to the output shaft in the low speed range, and means for deactuating said clutch and actuating said speed ratio fixing means to transmit all power hydraulically from the input shaft to the output shaft in the high speed range, said control means including means for varying the hydraulic transmission ratio to reduce the speed of the output shaft to zero in both the high and low speed ranges.

Claim 5

A hydromechanical transmission as defined in claim 1, wherein said gear ratio fixing means includes a clutch for selectively locking the differential gears for rotation as a unit.

Claim 6

A hydromechanical transmission as defined in claim 1, wherein said differential gearing is sized so that the speed range in high speed range is greater than the speed range in the low speed range for a corresponding change in the variable speed hydraulic transmission.

Claim 7

A hydromechanical transmission: comprising, an input shaft, an output shaft, two power paths between the input shaft and the output shaft including a mechanical path and a hydraulic path, said hydraulic path including a variable speed hydraulic transmission, a differential unit for combining power from said mechanical path and said hydraulic path including a first gear, clutch means selectively drivingly connecting said first gear to the input shaft and defining the mechanical path, a second gear drivingly connected to the hydraulic transmission, a third gear drivingly connected to said output shaft, means for selectively fixing the speed ratio between said first, second and third gears, and control means to vary the ratio of the hydraulic transmission for providing a reversible output low speed range and a reversible output high speed range, said means for providing a reversible output low speed range and a reversible output high speed range including means to engage said clutch and disengage said gear ratio fixing means to transmit power hydromechanically through both paths from the input shaft to the output shaft in the low speed range, means for disengaging said clutch and engaging said speed ratio fixing means to transmit all power hydraulically from the input shaft to the output shaft in the high speed range, said control means including control means in each of said low speed range and said high speed range for effecting reversal of said output shaft.

Claim 8

A hydromechanical transmission: comprising, an input shaft, an output shaft, two power paths between the input shaft and the output shaft including a mechanical path and a hydraulic path, said hydraulic path including a variable speed hydraulic transmission, a differential unit for combining power from said mechanical path and said hydraulic path including a first gear, clutch means selectively drivingly connecting said first gear to the input shaft and defining the mechanical path, a second gear drivingly connected to the hydraulic transmission, a third gear drivingly connected to said output shaft, means for selectively fixing the speed ratio between said first, second and third gears, and control means to vary the ratio of the hydraulic transmission for providing a reversible output low speed range and a reversible output high speed range, said means for providing a reversible output low speed range and a reversible output high speed range including means to engage said clutch and disengage said gear ratio fixing means to transmit power hydromechanically through both paths from the input shaft to the output shaft in the low speed range, means for disengaging said clutch and engaging said speed ratio fixing means to transmit all power hydraulically from the input shaft to the output shaft in the high speed range, said control means including control means in each of said low speed range and said high speed range for effecting reversal of said output shaft.

Claim 9

A hydromechanical transmission as defined in claim 4, wherein said means for effecting reversal of the output shaft in the low speed range includes means for varying the hydraulic transmission speed ratio to subtract sufficient speed from the differential to reverse the direction of rotation of the output shaft.

Claim 10

A hydromechanical transmission as defined in claim 5, wherein said means for effecting reversal of the output shaft in the high speed range includes means to vary the ratio of the hydraulic transmission to reverse the direction of rotation of the second gear in the differential.

Claim 11

A hydromechanical transmission, comprising: an input shaft, an output shaft, a differential including a first gear, a second and a third gear, first clutch means selectively connecting said first gear to said input shaft, a hydraulic transmission having an input driven by said input shaft and an output drivingly connected to said second gear, said third gear being drivingly connected to said output shaft, second clutch means selectively locking said differential gears together for rotation as a unit, means for varying the displacement of the hydraulic transmission from maximum in one direction to neutral, and maximum in the other direction, control means providing a split drive low speed range including means locating the displacement varying means between neutral and maximum on one side of neutral to subtract sufficient speed from the differential to reduce the output shaft to zero, said control means in the low speed range engaging said first clutch and disengaging said second clutch, said control means providing a straight hydRaulic high speed range including means for locating said displacement varying means in neutral to effect zero output from said output shaft, said control means in the high speed range disengaging said first clutch means and engaging said second clutch means.

Claim 12

A hydromechanical transmission, comprising: an input shaft, an output shaft, a differential including a first gear, a second and a third gear, first clutch means selectively connecting said first gear to said input shaft, a hydraulic transmission having an input driven by said input shaft and an output drivingly connected to said second gear, said third gear being drivingly connected to said output shaft, second clutch means selectively locking said differential gears together for rotation as a unit, means for varying the displacement of the hydraulic transmission from maximum in one direction to neutral, and maximum in the other direction, control means providing a split drive low speed range including means locating the displacement varying means between neutral and maximum on one side of neutral to subtract sufficient speed from the differential to reduce the output shaft to zero, said control means in the low speed range engaging said first clutch and disengaging said second clutch, said control means providing a straight hydRaulic high speed range including means for locating said displacement varying means in neutral to effect zero output from said output shaft, said control means in the high speed range disengaging said first clutch means and engaging said second clutch means.

Claim 13

A hydromechanical transmission as defined in claim 7, wherein said control means for said high speed range and said low speed range includes a handle pivotally mounted, means connecting said handle to control the displacement varying means during pivotal movement of said handle, means for locating said handle in a first pivotal position defining the displacement of the displacement varying means at zero output speed in the low speed range, means for locating said handle in a second pivotal position defining the displacement of the displacement varying means at zero output speed in the high speed range of the transmission.

Claim 14

A hydromechanical transmission as defined in claim 8, wherein said handle is movable in a direction transverse to said pivotal movement from a first transverse position to a second transverse position for controlling said clutches, means responsive to the positioning of said handle in the first transverse position for actuating said first clutch and deactuating said second clutch, means responsive to the positioning of said handle in the second transverse position for deactuating said first clutch and actuating said second clutch.

Claim 15

A hydromechanical transmission, comprising: an input shaft, an output shaft, differential gearing including a first gear, a clutch selectively connecting said first gear to said input shaft, a second gear, a hydraulic transmission connecting said second gear to one of said shafts, means for varying the displacement of said hydraulic transmission, a third gear drivingly connected to said output shaft, means selectively fixing the speed ratio of the gears, means for effecting a first low speed range including means for actuating said clutch and deactuating said speed ratio fixing means to transmit power hydromechanically through both paths from the input shaft to the output shaft, means for effecting a second high speed range including means for deactuating said clutch and actuating said speed ratio fixing means to transmit all power hydraulically from the input shaft to the output shaft, said differential gearing being arranged so that zero output speed in the first range is effected at a different hydraulic transmission displacement than in the second speed range, and control means for said displacement varying means having a first position defining zero output speed in said first range and a second position defining zero output in the second range.

Claim 16

A hydromechanical transmission, comprising: an input shaft, an output shaft, differential gearing including a first gear, a clutch selectively connecting said first gear to said input shaft, a second gear, a hydraulic transmission connecting said second gear to one of said shafts, means for varying the displacement of said hydraulic transmission, a third gear drivingly connected to said output shaft, means selectively fixing the speed ratio of the gears, means for effecting a first low speed range including means for actuating said clutch and deactuating said speed ratio fixing means to transmit power hydromechanically through both paths from the input shaft to the output shaft, means for effecting a second high speed range including means for deactuating said clutch and actuating said speed ratio fixing means to transmit all power hydraulically from the input shaft to the output shaft, said differential gearing being arranged so that zero output speed in the first range is effected at a different hydraulic transmission displacement than in the second speed range, and control means for said displacement varying means having a first position defining zero output speed in said first range and a second position defining zero output in the second range.

Claim 17

A hydromechanical transmission, comprising: an input shaft, an output shaft, differential gearing including a first gear, a clutch selectively connecting said first gear to said input shaft, a second gear, a hydraulic transmission connecting said second gear to one of said shafts, means for varying the displacement of said hydraulic transmission, a third gear drivingly connected to said output shaft, means selectively fixing the speed ratio of the gears, means for effecting a first speed range including means for actuating said clutch and deactuating said speed ratio fixing means, means for effecting a second speed range including means for deactuating said clutch and actuating said speed ratio fixing means, said differential gearing being arranged so that zero output speed in the first range is effected at a different hydraulic transmission displacement than in the second speed range, and control means for said displacement varying means having a first position defining zero output speed in said first range and a second position defining zero output in the second range, said control means including a handle pivotal about an axis, means responsive to movement of said handle about said axis for controlling said displacement varying means, means for selectively holding said handle in said first and Second positions, said handle being movable in a direction transverse to movement about said axis from a third position to a fourth position, means responsive to movement of said handle to said third position for actuating said clutch and deactuating said means for fixing the speed ratio of the differential, and means responsive to movement of the handle to the fourth position for deactuating said clutch and actuating said means for fixing the speed ratio of the differential.

Claim 18

A hydromechanical transmission, comprising: an input shaft, an output shaft, differential gearing including a first gear, a clutch selectively connecting said first gear to said input shaft, a second gear, a hydraulic transmission connecting said second gear to one of said shafts, means for varying the displacement of said hydraulic transmission, a third gear drivingly connected to said output shaft, means selectively fixing the speed ratio of the gears, means for effecting a first speed range including means for actuating said clutch and deactuating said speed ratio fixing means, means for effecting a second speed range including means for deactuating said clutch and actuating said speed ratio fixing means, said differential gearing being arranged so that zero output speed in the first range is effected at a different hydraulic transmission displacement than in the second speed range, and control means for said displacement varying means having a first position defining zero output speed in said first range and a second position defining zero output in the second range, said control means including a handle pivotal about an axis, means responsive to movement of said handle about said axis for controlling said displacement varying means, means for selectively holding said handle in said first and Second positions, said handle being movable in a direction transverse to movement about said axis from a third position to a fourth position, means responsive to movement of said handle to said third position for actuating said clutch and deactuating said means for fixing the speed ratio of the differential, and means responsive to movement of the handle to the fourth position for deactuating said clutch and actuating said means for fixing the speed ratio of the differential.

Claim 19

A hydromechanical transmission as defined in claim 11, including means mounting the handle for movement parallel to the pivot axis, a guide plate for said handle, said guide plate having spaced parallel slots each adapted to control movement of the handle about said axis in one of the first or second ranges, said first position of said handle being located in one of said slots, said second position of said handle being located in the other of said slots, a third slot interconnected with said first and second slots at said first and second positions to permit shifting of said handle from one slot to the other, said third slot defining the third and fourth positions of said handle so that control of said clutch and gear ratio fixing means is achieved as the handle is moved through the third slot.

Claim 20

A hydromechanical transmission as defined in claim 12, including a guide plate for guiding movement of the handle about said axis and having a slot therein.

Claim 21

A hydromechanical transmission as defined in claim 13, including means mounting said handle for motion transverse to the pivot axis, a first pin on said handle defining said third position thereof when engaging one side of said plate, and a second pin on said handle defining said fourth position of the handle when engaging the opposite side of said plate.

Claim 22

A hydromechanical transmission as defined in claim 14, wherein said slot has a first recess therein permitting movement of the first pin therethrough and defining the first position of the handle with both pins on one side of the plate, said slot having a second recess therein permitting movement of the second pin therethrough and defining the second position of the handle with both pins on the other side of the plate, whereby the handle may be moved from zero output in the first mode to zero output in the second mode by moving the first pin through the first recess, sliding the handle toward the second recess with the pins straddling the plate, and moving the second pin through the second recess.

Claim 23

A hydromechanical transmission as defined in claim 14, wherein said plate has recesses at opposite sides of said slot permitting movement of both sides through the plate at a pivotal position of the handle where the output speed of the transmission is the same in both ranges.

Claim 24

A hydromechanical transmission as defined in claim 14, including a first hand grip portion pivotal on said handle and carrying the first pin, a second hand grip portion pivotal on the handle and carrying the second pin, means mounting the hand grip portion for movement between positions where the pins will not pass through the plate recesses, and portions where the pins will pass through the plate recesses.

Claim 25

A hydromechanical transmission as defined in claim 14, wherein said slot has a first recess defining zero output shaft speed in one speed range and a second recess defining zero output shaft speed in the other speed range of the transmission, said handle bars being movable into said recesses when adjacent thereto to hold the handle in the neutral position in both speed ranges.

Claim 26

A hydromechanical transmission as defined in claim 14, said handle being movable to a fifth position where the pins straddle said plate, means responsive to movement of the handle to the fifth position for deactuating both said clutch and said means for fixing the speed ratio of said differential.

Claim 27

A hydromechanical transmission as defined in claim 19, wherein each of said handle bars has a piN extending therefrom, the pin on one of said bars being slidable on top of the plate holding the handle in a position actuating one of said clutches, the pin on the other of said bars being slidable on the bottom of said plate holding the handle in a position actuating the other of said clutches, said recesses being sufficiently small so that the pins cannot pass therethrough without compressing the handle bars to prevent inadvertent shifting of the clutches.

Claim 28

A hydromechanical transmission: comprising, an input shaft, an output shaft, two power paths between the input shaft and the output shaft including a mechanical path and a hydraulic path, said hydraulic path including a variable speed hydraulic transmission, a differential unit for combining power from said mechanical path and said hydraulic path including a first gear, first clutch means selectively drivingly connecting said first gear to the input shaft and defining the mechanical path, a second gear drivingly connected to the hydraulic transmission, a third gear drivingly connected to said output shaft, second clutch means for selectively fixing the speed ratio between said first, second and third gears, control means for providing a reversible output low speed range and a reversible output high speed range, means for synchronously engaging said first clutch means and disengaging the second clutch means to establish said low speed range to transmit power hydromechanically through both paths from the input shaft to the output shaft, and means for synchronously engaging said second clutch means and disengaging the first clutch means to establish said high speed range to transmit all power hydraulically from the input shaft to the output shaft.

Claim 29

A hydromechanical transmission: comprising, an input shaft, an output shaft, two power paths between the input shaft and the output shaft including a mechanical path and a hydraulic path, said hydraulic path including a variable speed hydraulic transmission, a differential unit for combining power from said mechanical path and said hydraulic path including a first gear, first clutch means selectively drivingly connecting said first gear to the input shaft and defining the mechanical path, a second gear drivingly connected to the hydraulic transmission, a third gear drivingly connected to said output shaft, second clutch means for selectively fixing the speed ratio between said first, second and third gears, control means for providing a reversible output low speed range and a reversible output high speed range, means for synchronously engaging said first clutch means and disengaging the second clutch means to establish said low speed range to transmit power hydromechanically through both paths from the input shaft to the output shaft, and means for synchronously engaging said second clutch means and disengaging the first clutch means to establish said high speed range to transmit all power hydraulically from the input shaft to the output shaft.

Claim 30

A hydromechanical transmission, comprising: an input shaft, an output shaft, differential gearing including a first gear, a first clutch including elements engageable for selectively connecting said first gear to said input shaft, a second gear, a hydraulic transmission connecting said second gear to one of said shafts, means for varying the displacement of said hydraulic transmission, a third gear drivingly connected to said output shaft, a second clutch including elements engageable for selectively fixing the speed ratio of the gears, means for effecting a first speed range including means for actuating said first clutch and deactuating said second clutch, means for effecting a second speed range including means for deactuating said first clutch and actuating said second clutch, said differential gearing being arranged so that zero output speed in the first range is effected at a different hydraulic transmission displacement than in the second speed range, and control means for disengaging both clutches to establish transmission neutral, and for engaging the elements of either clutch while synchronous to shift from neutral to either range at zero output, and for engaging the elements of either clutch while rotating synchronously to shift from one range to the other at a predetermined output speed.

Claim 31

A hydromechanical transmission, comprising: an input shaft, an output shaft, differential gearing including a first gear, a first clutch including elements engageable for selectively connecting said first gear to said input shaft, a second gear, a hydraulic transmission connecting said second gear to one of said shafts, means for varying the displacement of said hydraulic transmission, a third gear drivingly connected to said output shaft, a second clutch including elements engageable for selectively fixing the speed ratio of the gears, means for effecting a first speed range including means for actuating said first clutch and deactuating said second clutch, means for effecting a second speed range including means for deactuating said first clutch and actuating said second clutch, said differential gearing being arranged so that zero output speed in the first range is effected at a different hydraulic transmission displacement than in the second speed range, and control means for disengaging both clutches to establish transmission neutral, and for engaging the elements of either clutch while synchronous to shift from neutral to either range at zero output, and for engaging the elements of either clutch while rotating synchronously to shift from one range to the other at a predetermined output speed.

Claim 32

A hydromechanical transmission, comprising: an input shaft, an output shaft, differential gearing including a first gear, a first clutch for selectively connecting said first gear to said input shaft, a second gear, a hydraulic transmission connecting said second gear to one of said shafts, means for varying the displacement of said hydraulic transmission, a third gear drivingly connected to said output shaft, a second clutch for selectively fixing the speed ratio of the gears, means for effecting a first speed range including means for actuating said first clutch and deactuating said second clutch, means for effecting a second speed range including means for deactuating said first clutch and actuating said second clutch, said differential gearing being arranged so that zero output speed in the first range is effected at a different hydraulic transmission displacement than in the second speed range, control means for said displacement varying means having a first position defining zero output speed in said first range and a second position defining zero output speed in the second range, and control means for disengaging both clutches to establish transmission neutral and for engaging either clutch to shift synchronously from neutral to either range.

Claim 33

A hydromechanical transmission, comprising: an input shaft, an output shaft, differential gearing including a first gear, a first clutch for selectively connecting said first gear to said input shaft, a second gear, a hydraulic transmission connecting said second gear to one of said shafts, means for varying the displacement of said hydraulic transmission, a third gear drivingly connected to said output shaft, a second clutch for selectively fixing the speed ratio of the gears, means for effecting a first speed range including means for actuating said first clutch and deactuating said second clutch, means for effecting a second speed range including means for deactuating said first clutch and actuating said second clutch, said differential gearing being arranged so that zero output speed in the first range is effected at a different hydraulic transmission displacement than in the second speed range, control means for said displacement varying means having a first position defining zero output speed in said first range and a second position defining zero output speed in the second range, and control means for disengaging both clutches to establish transmission neutral and for engaging either clutch to shift synchronously from neutral to either range.

Claim 34

A transmission as defined in claim 23, including means for engaging either clutch to shift synchronously from either range to the other at a predetermined output speed.