A continuously variable speed transmission and steering differential having a central drive axle, two pairs of sheaves and two shift arms. The drive axel is driven by an external power source. The two pairs of sheaves, left and right, are mounted to the drive axel. Each pair of sheaves includes a fixed drive sheave and a movable drive sheave. Each movable drive sheave is positioned by a shift arm. Shifting the shift arms left or right varies the gear ratio between the left and right pair of sheaves thereby providing steering control. Narrowing the distance between the shaft arms increases the gear ratio and consequently puts the transmission into a higher gear, thereby providing speed control.

The present concept is a continuously variable speed transmission and steering differential. It includes a laterally extending central drive axle driven by an external power source, two pairs of drive sheaves mounted to drive axles, and a means for transmitting rotational energy from the drive sheaves to the drive axles. There are two extended shift arms spaced apart for controlling the positioning of movable drive sheaves. Narrowing or increasing the gap between shift arms, does the same for the gap between the drive sheaves, increasing or decreasing the gear ration respectively which provides speed control. Shifting the shift arms left or right varies the gear ratio between the left and right pair of sheaves, providing differential speed between the left and right driven axles, which provides steering control.

A transmission system for a vehicle having a belt drive transmission. The belt drive has an adjustable input and output ratio, where the output of the belt drive is provided as a first input to a differential coupling. A further rotating connection is provided as a second input to the differential coupling, so that the output of the differential coupling is arranged as the output of the transmission system. Accordingly, the transmission output is based on the aggregate sum of the rotation of the first and second inputs to the differential coupling, wherein adjustment of the input and output ratio of the belt drive allows for a continuously variable transmission system.

A transmission system for a vehicle having a belt drive transmission. The belt drive has an adjustable input:output ratio, where the output of the belt drive is provided as a first input to a differential coupling. A further rotating connection is provided as a second input to the differential coupling, so that the output of the differential coupling is arranged as the output of the transmission system. Accordingly, the transmission output is based on the aggregate sum of the rotation of the first and second inputs to the differential coupling, wherein adjustment of the input:output ratio of the belt drive allows for a continuously variable transmission system.

A continuously variable transmission (CVT) system, which turns the rear wheels of a lawn mower or similar vehicle at different speeds in a coordinated method with the front steering wheels in order to achieve the best turning radius (including a tight or zero turn radius, if desired) under most conditions. The system comprises two stages: the first stage comprising a Fixed Center Distance CVT pulley system, and the second stage comprising dual CVTs (e.g., left and right) that input into dual gear reducers (left and right), which are mechanically connected to the rear wheels. The second stage dual CVTs (left and right) are synchronized with the steering wheel, thus achieving different rear wheel speeds and/or directions based on the steering wheel position.

A variable speed belt drive system having a driving pulley, a V-belt, and a driven pulley connected to the driving pulley with the V-belt. The driven pulley includes a pulley shaft rotatable about a pulley axis, an inboard pulley-half having a first contact surface that is inclined relative to the axis of the pulley shaft that defines a first belt-contacting wall of driven pulley, wherein the first contact surface is fixed relative to the pulley shaft. The driven pulley has an outboard pulley-half having a second contact surface that is opposite the first contact surface and that is inclined relative to the axis of the pulley shaft, the outboard pulley-half being movable relative the inboard pulley-half such that the second contact surface is moveable relative to the driven pulley shaft. The inboard pulley-half is connected to the outboard pulley-half with two or more tension struts.

A continuously-variable transmission (CVT) assembly is employed for transmitting a torque from an external power-source. The CVT includes a variable-diameter input pulley and a variable-diameter output pulley, each having a respective range of adjustment. The CVT also includes a continuous torque-transmitting element extending between the variable-diameter input pulley and the variable-diameter output pulley, and thereby operatively connecting the input pulley to the output pulley. The CVT additionally includes a first elastic element having a first zero stiffness over the range of adjustment of the variable-diameter input pulley and configured to apply a first constant spring clamping force via the input pulley to the continuous torque-transmitting element. Furthermore, the CVT includes a second elastic element having a second zero stiffness over the range of adjustment of the variable-diameter input pulley and configured to apply a second constant spring clamping force via the output pulley to the continuous torque-transmitting element.

A line of transmissions is described having a first multi-stage reduction gearbox that includes a first stage (first reduction set) having a variable ratio belt drive with a first fixed ratio, and a second stage (second reduction set) having fixed gears; and a second multi-stage reduction gearbox including a first stage having the same variable ratio belt drive as the first multi-stage reduction gearbox but with a second fixed ratio different from the first, and a second stage having the same fixed gears as the second stage of the first multi-stage reduction gearbox.

A line of transmissions is described having a first multi-stage reduction gearbox that includes a first stage (first reduction set) having a variable ratio belt drive with a first fixed ratio, and a second stage (second reduction set) having fixed gears; and a second multi-stage reduction gearbox including a first stage having the same variable ratio belt drive as the first multi-stage reduction gearbox but with a second fixed ratio different from the first, and a second stage having the same fixed gears as the second stage of the first multi-stage reduction gearbox.

A modular, continuously variable ratio transmission adapted to be coupled between the drive motor of a dual rotor riding trowel and the lower drive train. First and second rigid, generally planar frame plates are secured in parallel relation by a plurality of spacers. The first fame plate has a clearance orifice for admitting a portion of the trowel engine. A stub shaft receives input power and rotates a first pulley that drives a second pulley with a reduced diameter. A first jackshaft driven by said second pulley drives a variable CVT drive pulley affixed externally of the module. A second variable drive pulley coupled to said first variable drive pulley by a belt drives a second jackshaft splined to a fifth pulley that is coupled to a sixth pulley having a diameter greater than the diameter of said fifth pulley. The sixth pulley is coupled to trowel gearbox drive shafts.