Hydromechanical transmission

Claim 2

A hydromechanical transmission, comprising, a. a mechanical differential including a-1. an input gear, a-2. an output gear, and a-3. a control gear, b. a hydrostatic transmission including b-1. a pair of hydraulic units connected in hydraulic circuit, b-2. means connecting one hydraulic unit to rotate with the input gear, b-3. means connecting the other hydraulic unit to rotate with the control gear, and b-4. means for varying the displacement of one hydraulic unit, c. means for controlling the displacement varying means, and d. releasable means preventing reverse rotation of the control gear on cold starts.

Claim 3

A hydromechanical transmission as defined in claim 1, wherein the releasable means comprises detent teeth on the control gear, and a detent pawl releasably engageable with the detent teeth.

Claim 4

A hydromechanical transmission as defined in claim 2, including means normally biasing the detent pawl toward the detent teeth, and fluid operable means for retracting the detent against the biasing means.

Claim 5

A hydromechanical transmission as defined in claim 2, including a lock pawl releasably engageable with the detent pawl for holding the detent pawl released.

Claim 6

A hydromechanical transmission as defined in claim 4, including temperature responsive means for extending the lock pawl toward the detent pawl when the ambient temperature reaches a predetermined value.

Claim 7

A hydromechanical transmission, comprising, a. an input shaft adapted to be drivingly connected to a source of power, b. an output shaft adapted to be drivingly connected to a device to be driven at a controlled speed, c. a mechanical differential including c-1. an input gear rotatable with the input shaft, c-2. an output gear rotatable with the output shaft, and c-3. a control gear, d. a hydrostatic transmission including d-1. a pair of hydraulic units connected in closed hydraulic circuit, d-2. means connecting one hydraulic unit to rotate with the input shaft, d-3. means connecting the other hydraulic unit to rotate with the control gear, and d-4. means for varying the displacement of one hydraulic unit, e. means for controlling the displacement varying means to vary the speed of the output shaft relative to the speed of the input shaft, and f. releasable means preventing reverse rotation of the control gear on cold starts.

Claim 8

A hydromechanical transmission, comprising, a. an input shaft adapted to be drivingly connected to a source of power, b. an output shaft adapted to be drivingly connected to a device to be driven at a controlled speed, c. a mechanical differential including c-1. an input gear rotatable with the input shaft, c-2. an output gear rotatable with the output shaft, and c-3. a control gear, d. a hydrostatic transmission including d-1. a pair of hydraulic units connected in closed hydraulic circuit, d-2. means connecting one hydraulic unit to rotate with the input shaft, d-3. means connecting the other hydraulic unit to rotate with the control gear, and d-4. means for varying the displacement of one hydraulic unit, e. means for controlling the displacement varying means to vary the speed of the output shaft relative to the speed of the input shaft, and f. releasable means preventing reverse rotation of the control gear on cold starts.

Claim 9

A hydromechanical transmission, comprising, a. an input shaft adapted to be drivingly connected to a source of power, b. an output shaft adapted to be drivingly connected to a device to be driven at a contRolled speed, c. a mechanical differential including c-1. an input gear rotatable with the input shaft, c-2. an output gear rotatable with the output shaft, and c-3. a control gear, d. a variable transmission for controlling the control gear to vary the speed of the output shaft relative to the speed of the input shaft, and e. releasable means preventing reverse rotation of the control gear on cold starts.

Claim 10

A hydromechanical transmission, comprising, a. an input shaft adapted to be drivingly connected to a source of power, b. an output shaft adapted to be drivingly connected to a device to be driven at a contRolled speed, c. a mechanical differential including c-1. an input gear rotatable with the input shaft, c-2. an output gear rotatable with the output shaft, and c-3. a control gear, d. a variable transmission for controlling the control gear to vary the speed of the output shaft relative to the speed of the input shaft, and e. releasable means preventing reverse rotation of the control gear on cold starts.

Claim 11

A hydromechanical transmission as defined in claim 7, wherein the releasable means comprises detent teeth on the control gear, a detent pawl releasably engageable with the detent teeth, means normally biasing the detent pawl toward the detent teeth, and fluid operable means for retracting the detent against the biasing means.

Claim 12

A hydromechanical transmission as defined in claim 8, including a lock pawl releasably engageable with the detent pawl for holding the detent pawl released, and temperature responsive means for extending the lock pawl toward the detent pawl when the ambient temperature reaches a predetermined value.

Claim 13

A hydromechanical transmission, comprising, a. an input shaft adapted to be drivingly connected to a source of power, b. an output shaft adapted to be drivingly connected to a device to be driven at a controlled speed, c. a mechanical differential including, c-1. a gear carrier rotatable about a predetermined axis, c-2. a pair of meshing pinions rotatable on the carrier about axes parallel to the carrier axis, and c-3. a pair of internal ring gears rotatable respectively in mesh with the pinions, d. means connecting one ring gear to rotate with the input shaft, e. means connecting the other ring gear to rotate with the output shaft, f. a hydrostatic transmission including f-1. a variable displacement hydraulic unit rotatable with the input shaft, f-2. a second hydraulic unit rotatable with the carrier, and f-3. conduit means connecting the two units in closed hydraulic circuit, g. means to control the variable displacement hydraulic unit, to vary the displacement of the output shaft relative to the speed of the input shaft, and h. releasable detent means for preventing reverse rotation of the carrier on cold starts.

Claim 14

A hydromechanical transmission, comprising, a. an input shaft adapted to be drivingly connected to a source of power, b. an output shaft adapted to be drivingly connected to a device to be driven at a controlled speed, c. a mechanical differential including, c-1. a gear carrier rotatable about a predetermined axis, c-2. a pair of meshing pinions rotatable on the carrier about axes parallel to the carrier axis, and c-3. a pair of internal ring gears rotatable respectively in mesh with the pinions, d. means connecting one ring gear to rotate with the input shaft, e. means connecting the other ring gear to rotate with the output shaft, f. a hydrostatic transmission including f-1. a variable displacement hydraulic unit rotatable with the input shaft, f-2. a second hydraulic unit rotatable with the carrier, and f-3. conduit means connecting the two units in closed hydraulic circuit, g. means to control the variable displacement hydraulic unit, to vary the displacement of the output shaft relative to the speed of the input shaft, and h. releasable detent means for preventing reverse rotation of the carrier on cold starts.

Claim 15

A hydromechanical transmission as defined in claim 10, wherein the releasable detent means comprises ratchet teeth on the gear carrier, a detent plunger releasably engageable with the ratchet teeth, means normally biasing the detent plunger toward the detent teeth, and selectively operable means for retracting the detent plunger against the biasing means.

Claim 16

A hydromechanical transmission as defined in claim 11, including a lock plunger releasably engageable with the detent plunger to hold the latter retracted, and temperature responsive means controlling the lock plunger.

Claim 17

A hydromechanical transmission as defined in claim 12, wherein the temperature responsive means comprises metallic temperature responsive washer means on the lock plunger for extending the lock plunger in event of predetermined high ambient temperature.

Claim 18

A hydromechanical transmission as defined in claim 12, wherein the temperature responsive means comprises metallic temperature responsive washer means on the lock plunger for retracting the lock plunger in event of predetermined low ambient temperature.

Claim 19

A hydromechanical transmission, comprising, a. an input shaft adapted to be drivingly connected to a source of power, b. an output shaft adapted to be drivingly connected to a device to be driven at a controlled speed, c. a mechanical differential including, c-1. a gear carrier rotatable about a predetermined axis, c-2. a pair of elongate meshing pinions rotatable on stationary bearing shafts on the carrier about axes parallel to the carrier axis, and c-3. a pair of coaxial internal ring gears rotatably mounted concentric about tHe carrier axis and respectively in mesh with the pinions, d. means connecting the input shaft to rotate one ring gear, e. means connecting the other ring gear to rotate the output shaft, f. a hydrostatic transmission including f-1. a variable displacement hydraulic unit driven by the input shaft, f-2. a second hydraulic unit rotatable with the carrier, f-3. conduit means connecting the two units in closed hydraulic circuit, and f-4. means responsive to the speed of the output shaft to control the variable displacement hydraulic unit to maintain constant output speed, g. a charge pump driven by the output shaft to supply fluid to the hydrostatic transmission, h. detent means preventing reverse rotation of the carrier on cold starts, and i. means responsive to charge pressure for releasing the detent means.

Claim 20

A hydromechanical transmission, comprising, a. an input shaft adapted to be drivingly connected to a source of power, b. an output shaft adapted to be drivingly connected to a device to be driven at a controlled speed, c. a mechanical differential including, c-1. a gear carrier rotatable about a predetermined axis, c-2. a pair of elongate meshing pinions rotatable on stationary bearing shafts on the carrier about axes parallel to the carrier axis, and c-3. a pair of coaxial internal ring gears rotatably mounted concentric about tHe carrier axis and respectively in mesh with the pinions, d. means connecting the input shaft to rotate one ring gear, e. means connecting the other ring gear to rotate the output shaft, f. a hydrostatic transmission including f-1. a variable displacement hydraulic unit driven by the input shaft, f-2. a second hydraulic unit rotatable with the carrier, f-3. conduit means connecting the two units in closed hydraulic circuit, and f-4. means responsive to the speed of the output shaft to control the variable displacement hydraulic unit to maintain constant output speed, g. a charge pump driven by the output shaft to supply fluid to the hydrostatic transmission, h. detent means preventing reverse rotation of the carrier on cold starts, and i. means responsive to charge pressure for releasing the detent means.

Claim 21

A hydromechanical transmission as defined in claim 15, wherein the releasable detent means comprises ratchet teeth on the gear carrier, a detent plunger releasably engageable with the ratchet teeth, and means normally biasing the detent plunger toward the detent teeth.

Claim 22

A hydromechanical transmission as defined in claim 16, including a lock plunger releasably engageable with the detent plunger to hold the latter retracted, and temperature responsive means controlling the lock plunger.