Power transmission apparatus

Claim 2

Power transmission apparatus comprising a transmission unit including a housing, an input shaft which is adapted to be coupled to a prime mover for operative rotation relative to the housing, an output shaft which is operatively rotatable relative to the housing, and variable transmission control means coupling the input shaft with the output shaft to control the transmission of power therebetween, wherein the housing is journaled in a support structure for turning movement relative to the support structure about the axis of rotation of the output shaft, and means is provided for applying a balancing torque to the housing to counterbalance the reaction torque on the housing during rotation of the output shaft, the angular orientation of the housing relative to the support structure, which angular orientation is dependent on the value of said reaction torque, so controlling the transmission control means that on variation in said angular orientation, resultant on an increase in said reaction torque, the setting of the transmission control means is varied to produce a corresponding increase in the output torque at the output shaft with a corresponding reduction in the speed of rotation thereof, and that on variation in said angular orientation, resultant on a decrease in said reaction torque, the setting of the transmission control means is varied to produce a corresponding decrease in the output torque at the output shaft with a corresponding increase in the speed of rotation thereof.

Claim 3

Power transmission apparatus as claimed in claim 1, wherein the transmission unit comprises a hydrostatic transmission unit.

Claim 4

Power transmission apparatus as claimed in claim 1, wherein the transmission unit comprises a hydrostatic transmission ball piston pump and motor assembly.

Claim 5

Power transmission apparatus as claimed in claim 1, wherein the direction of rotation of the output shaft is reversible by variation in the setting of the variable transmission control means.

Claim 6

Power transmission apparatus as claimed in claim 1, wherein the means for applying a balancing torque to the housing comprises a coil compression spring, a member being rigidly connected to the housing with the spring acting between said member and a stop thereby to exert on the housing a balancing torque which is opposite in direction to the reaction torque on the housing.

Claim 7

Power transmission apparatus as claimed in claim 5, wherein a control member is connected to the stop, the control member being so movable as to vary the magnitude of the torque exerted on the housing by the spring.

Claim 8

Power transmission apparatus as claimed in claim 6, wherein a hydraulic power assist system is interpolated in the connection between the control member and the stop, the system comprising a hydraulically operable piston and cylinder assembly which is connected between the stop and a fixed structure, a valve having an inlet for pressurized fluid and an outlet for exhaust fluid, and two hydraulic lines connected between the valve and the cylinder with one of the lines in communication with the interior of the cylinder on one side of the piston and the other of the lines in communication with the interior of the cylinder on the other side of the piston, the valve being operable by movement of the control member to vary the net hydraulic pressure acting on the piston and hence vary the magnitude of the torque exerted on the housing by the spring.

Claim 9

Power transmission apparatus for use in a vehicle, the apparatus comprising two transmission units each of which includes a housing, an input shaft and an output shaft which are operatively rotatable relative to the housing, and variable transmission control means coupling the input shaft with the output shaft to control the transmission of power therebetween, the input shafts of the units being adapted to be coupled to a prime mover for operative rotation relative to the housings, wherein the housing of each unit is journaled in a support structure for turning movement relative to the support structure about the axis of rotation of the output shaft of the unit, the housings being interconnected to prevent relative rotation therebetween about said axes, and means is provided for applying a balancing torque to the housings to counterbalance the reaction torque on the housings during rotation of the output shafts, the angular orientation of the housings about the axis of rotation of the output shafts, which angular orientation is dependent on the value of said reaction torque, so controlling the transmission control means that variation in said angular orientation, resultant on an increase in said reaction torque, the settings of the transmission control means are varied to produce corresponding increases in the output torques at the output shafts with corresponding reductions in the speed of rotation thereof, and that on variation in said angular orientation, resultant on a decrease in said reaction torque, the settings of the transmission control means are varied to produce corresponding decreases in the output torques at the output shafts with corresponding increases in the speed of rotation thereof, and a steering assembly being so connected to the transmission control means of the two units that on actuation of said assembly the setting of the transmission control means of one of the units is varied to produce a reduction in the speed of rotation of the output shaft of said unit and simultaneously the setting of the transmission control means of the other of the units is varied to produce a corresponding increase in the speed of rotation of the output shaft of said other of the units.

Claim 10

Power transmission apparatus for use in a vehicle, the apparatus comprising two transmission units each of which includes a housing, an input shaft and an output shaft which are operatively rotatable relative to the housing, and variable transmission control means coupling the input shaft with the output shaft to control the transmission of power therebetween, the input shafts of the units being adapted to be coupled to a prime mover for operative rotation relative to the housings, wherein the housing of each unit is journaled in a support structure for turning movement relative to the support structure about the axis of rotation of the output shaft of the unit, the housings being interconnected to prevent relative rotation therebetween about said axes, and means is provided for applying a balancing torque to the housings to counterbalance the reaction torque on the housings during rotation of the output shafts, the angular orientation of the housings about the axis of rotation of the output shafts, which angular orientation is dependent on the value of said reaction torque, so controlling the transmission control means that variation in said angular orientation, resultant on an increase in said reaction torque, the settings of the transmission control means are varied to produce corresponding increases in the output torques at the output shafts with corresponding reductions in the speed of rotation thereof, and that on variation in said angular orientation, resultant on a decrease in said reaction torque, the settings of the transmission control means are varied to produce corresponding decreases in the output torques at the output shafts with corresponding increases in the speed of rotation thereof, and a steering assembly being so connected to the transmission control means of the two units that on actuation of said assembly the setting of the transmission control means of one of the units is varied to produce a reduction in the speed of rotation of the output shaft of said unit and simultaneously the setting of the transmission control means of the other of the units is varied to produce a corresponding increase in the speed of rotation of the output shaft of said other of the units.

Claim 11

Power transmission apparatus as claimed in claim 8, wherein each transmission unit comprises a hydrostatic transmission unit.

Claim 12

Power transmission apparatus for use in a vehicle, the apparatus comprising two transmission units each of which includes a housing, an input shaft and an output shaft which are operatively rotatable relative to the housing, and variable transmission control means coupling the input shaft with the output shaft to control the transmission of power therebetween, the input shafts of the units being adapted to be coupled to a prime mover for operative rotation relative to the housings, and the direction of rotation of the output shaft of each transmission unit being reversible by variation in the setting of the transmission coNtrol means of said unit, wherein the housing of each unit is journaled in a support structure for turning movement relative to the support structure about the axis of rotation of the output shaft of the unit, the housings being interconnected to prevent relative rotation therebetween about said axes, and means is provided for applying a balancing torque to the housings to counterbalance the reaction torque on the housings during rotation of the output shafts, the angular orientation of the housings about the axes of rotation of the output shafts, which angular orientation is dependent on the value of said reaction torque, so controlling the transmission control means that on variation in said angular orientation, resultant on an increase in said reaction torque, the settings of the transmission control means are varied to produce corresponding increases in the output torques at the output shafts with corresponding reductions in the speed of rotation thereof, and that on variation in said angular orientation, resultant on a decrease in said reaction torque, the settings of the transmission control means are varied to produce corresponding decreases in the output torques at the output shafts with corresponding increases in the speed of rotation thereof, and a steering assembly being so connected to the transmission control means of the two units that on actuation of said assembly the setting of the transmission control means of one of the units is varied to produce an algebraic reduction in the speed of rotation of the output shaft of said unit and simultaneously the setting of the transmission control means of the other of the units is varied to produce a corresponding algebraic increase in the speed of rotation of the output shaft of said other of the units.

Claim 13

Power transmission apparatus for use in a vehicle, the apparatus comprising two transmission units each of which includes a housing, an input shaft and an output shaft which are operatively rotatable relative to the housing, and variable transmission control means coupling the input shaft with the output shaft to control the transmission of power therebetween, the input shafts of the units being adapted to be coupled to a prime mover for operative rotation relative to the housings, and the direction of rotation of the output shaft of each transmission unit being reversible by variation in the setting of the transmission coNtrol means of said unit, wherein the housing of each unit is journaled in a support structure for turning movement relative to the support structure about the axis of rotation of the output shaft of the unit, the housings being interconnected to prevent relative rotation therebetween about said axes, and means is provided for applying a balancing torque to the housings to counterbalance the reaction torque on the housings during rotation of the output shafts, the angular orientation of the housings about the axes of rotation of the output shafts, which angular orientation is dependent on the value of said reaction torque, so controlling the transmission control means that on variation in said angular orientation, resultant on an increase in said reaction torque, the settings of the transmission control means are varied to produce corresponding increases in the output torques at the output shafts with corresponding reductions in the speed of rotation thereof, and that on variation in said angular orientation, resultant on a decrease in said reaction torque, the settings of the transmission control means are varied to produce corresponding decreases in the output torques at the output shafts with corresponding increases in the speed of rotation thereof, and a steering assembly being so connected to the transmission control means of the two units that on actuation of said assembly the setting of the transmission control means of one of the units is varied to produce an algebraic reduction in the speed of rotation of the output shaft of said unit and simultaneously the setting of the transmission control means of the other of the units is varied to produce a corresponding algebraic increase in the speed of rotation of the output shaft of said other of the units.

Claim 14

Power transmission apparatus as claimed in claim 8, wherein the means for applying a balancing torque to the housings comprises a coil compression spring, a member being rigidly connected to the housings with the spring acting between said member and a stop thereby to exert on the housings a balancing torque which is opposite in direction to the reaction torque on the housings, and wherein there is provided a rotatable control column having an upper end presenting a handgrip portion and a lower end, the column intermediate its ends incorporating a universal joint about which the upper portion of the column between the upper end thereof and the universal joint may be pivotally moved thereby, the stop being connected to the upper end of the column, to vary the magnitude of the torque exerted on the housings by the spring, the lower portion of the column between the universal joint and the lower end thereof presenting opposed, projecting arms one of which is connected by a first linkage to the transmission control means of one of the transmission units and the other of which is connected by a second linkage to the transmission control means of the other of the transmission units, and said lower portion of the column being pivotally movable about the universal joint in a direction towards and away from the transmission control means of the transmission units but being resiliently urged towards a predetermined position.