Abstract: The present invention relates to a combined directional and infinitely variable speed transmission which, through a single continuous V-belt pulley drive mechanism, is capable of infinitely variable changing speeds and direction with a single control. It employs an axially adjustable non-rotatable drive inducing input pulley whose effective operaing diameter can be adjusted to vary its dimentional ratio with a rotatable, fixed diameter orbiting output pulley rotatable driven on its own axis by a walking motion of the connecting V-belt about the non-rotatable input pulley. Prior art transmission all require some type of forward-reverse directional change mechanism completely separate and apart from the speed section of the transmission. The present invention eliminates such separate directional devices by being able to manipulate the ratio between the effective operating diameters of the pulleys to change direction at the same time that such ratio is determining the output speed of the transmission.

Abstract: A continuously variable transmission utilizes a cam loading device with a hydraulically controlled CVT of the metal V-belt type. The cam loading device applies an axial loading force to the pulley flanges in proportion to the output torque. A hydraulic mechanism positions the pulley flanges to compensate for the limited axial movement of the cam mechanism. A preload spring and hydraulic cushion provide a necessary preload while cushioning shock from reversal of torque. The loading force on the CVT is permitted to vary with the output torque to provide improved efficiency for a full range of automotive driving conditions.

Abstract: A control arrangement for a continuously variable transmission utilizes a lationship between force ratio, speed ratio and the factor of safety to determine the force necessary on the secondary sheave to prevent belt slippage. The control system improves the efficiency of the transmission by reducing the excess clamping force between the CVT chain-belt and the secondary pulley sheave.

Abstract: A traction control of an automobile with a continuously variable transmission is provided. According to this control, in order to improve start-up ability of the vehicle on a road surface with a low friction coefficient, a wheel acceleration is derived and when the wheel acceleration is greater than a predetermined value, the tendency of the transmission to upshift is increased.

Abstract: A belt-type continuously variable transmission in which a drive pulley mounted on an input shaft and a driven pulley mounted on an output shaft are connected by an endless belt, a forward- and backward-movement switchover mechanism for transmitting a driving force from an engine to the drive pulley is disposed adjacent the stationary pulley half of the drive pulley, and a starting clutch for transmitting the rotation of the output shaft to driving wheels is disposed adjacent stationary pulley half of the driven pulley. This ensures that dead spaces created in a section opposed to both the movable pulley halves which move axially can be utilized as spaces for disposition of the forward- and backward-movement switchover mechanism and the starting clutch, thereby enabling the forward- and backward-movement switchover mechanism and the starting clutch to be disposed in a compact layout.

Abstract: Device for the regulation of an automatic transmission unit, in particular a transmission unit composed of a torque converter, a foreward coupling, a reverse coupling and a continuously variable transmission, characterized in that this device consists of a pump; a first regulating valve for the regulation of the continuously variable transmission; a second regulating valve with which a hydraulic medium for the torque converter can be controlled; a cut-off valve; and control means which supply a regulating pressure which can provide in the control of both the cut-off valve and the second regulating valve.

Abstract: A power train for use in a motor vehicle has an infinitely variable transmission with two sheaves and a belt which is trained over the sheaves. The sheaves have fixed and axially movable flanges, and one of the sheaves is driven by the engine through a torque sensor. A first hydraulic circuit has a first pump which can supply pressurized oil to the hydraulic motors for the axially movable sheaves at a pressure determined by the torque sensor. A second hydraulic circuit has a second pump serving to supply pressurized oil to a further motor which varies the ratio of the transmission and to two friction clutches between the second sheave and an output member. The pressure of oil in the second circuit is determined by a pressure regulating valve which is adjustable by a control unit in dependency on one or more parameters of the engine.

Abstract: New methods for controlling an automotive continuously variable transmission (CVT) during downshifting such that chain-belt slippage will not occur. The relationship between the primary and secondary sheave forces is used to predict and control the primary force so that the primary clamping force is sufficient to prevent slippage.

Abstract: Disclosed is an apparatus for controlling a continuously variable transmission for controlling a speed-change ratio so as to set an input number of revolutions of the continuously variable transmission mounted on a vehicle to a predetermined targeted value on the basis of engine performance at a predetermined throttle opening. The apparatus has a device for imparting an initial value of a range of the targeted value when a change in the throttle opening ceases and a device for changing the range of the targeted value when there is no change in the throttle opening. A range between the upper and lower limits of a targeted engine speed is rendered variable depending on the driver's requirements and the running state, making it possible to properly determine which of the characteristics is to be strengthened among the power performance, fuel consumption performance, control stability, and transmission efficiency.

Abstract: A continuously variable transmission provided with a primary pulley mounted on a primary shaft and a secondary pulley mounted on a secondary shaft. A transmission is passed over said pulleys. Both the primary pulley and the secondary pulley comprise a pair of discs. At least one of said discs is axially movable by a hydraulic cylinder, so as to adjust the position of the transmission around the pulleys and thus the transmission ratio of the transmission. The pump for providing fluid for said hydraulic cylinders has a regulable delivery, so as to enhance the transmission efficiency.

Abstract: An apparatus for controlling a continuously variable vehicle transmission includes a fixed pulley member and a movable pulley member which is supported for movement toward and away from the fixed pulley member. A groove defined between the pulley members has a width which is decreased and increased to thereby respectively increase and decrease the rotational radius of a belt which is received in the groove. A control arrangement executes speed change control to change the belt ratio. The control arrangement includes a control unit which receives throttle opening degree and vehicle velocity detection signals and determines first and second target engine rotational speed which are based respectively on these detection signals. The control unit determines an optimum target engine rotational speed based on the firt and second target engine rotational speeds and sets upper and lower limit values of the optimum target engine rotational speed in accordance with predetermined conditions.

Abstract: A power transmitting system has a belt drive continuously variable transmission for transmitting power of an engine to wheels of a motor vehicle through a torque converter with a lockup clutch. The transmission comprises a primary pulley connected to an output member of the torque converter, a secondary pulley operatively connected to the wheels, a primary cylinder and a secondary cylinder for changing effective diameters of both pulleys, a secondary pressure control valve for controlling secondary pressure applied to the secondary cylinder. Vehicle driving conditions for engaging and disengaging the lockup clutch are detected for producing an engagement or a disengagement signal. In response to the engagement signal, the locked up clutch is locked and the secondary pressure is reduced after a predetermined delay time. In response to the disengagement signal, the secondary pressure is increased and the lockup clutch is disengaged after a predetermined delay time.

Abstract: A transmission ratio control device for a controllable, continually variable V-belt transmission for motor vehicles includes a primary hydraulic line carrying the clamping pressure for the V-belt from the primary pressure chamber, a check valve opening against the pressure in the primary pressure chamber, a secondary hydraulic line carrying the clamping pressure for the V-belt from the secondary pressure chamber, and a second check valve opening against the pressure in the secondary pressure chamber. An adjustable pump is installed in a line connecting the first line, between the primary pressure chamber and the first check valve, to the second line, between the secondary pressure chamber and the secondary check valve. The adjustable pump is dependent on a control signal to control the continually variable gear ratio by pumping hydraulic fluid between the primary pressure chamber and the secondary pressure chamber.

Abstract: A continuously variable belt drive transmission has a torque converter with a lockup clutch. The lockup clutch is engaged in accordance with conditions of an engine and the transmission. Torque of the torque converter is estimated based on engine operating conditions and transmission conditions, and torque of the lockup clutch is estimated based on engine operating conditions and detected transmission conditions. The estimated converter torque and the estimated clutch torque are compared with each other for determining larger torque. The lockup clutch is disengaged when the estimated converter torque is larger than the estimated lockup clutch torque.

Abstract: A refrigeration system includes a compressor, a motor, variable pitch pulleys mounted on the ends of the compressor and motor shafts, and an endless belt looped around the motor and compressor pulleys for drivingly connecting the motor to the compressor. A sensor determines a variance in a refrigerant characteristic of the system from a predetermined value. An electrically powered actuator is responsive to the sensor and effects axial movement to one pulley component of the motor for thereby changing the pitch diameter of the motor pulley and to in turn vary the pitch diameter of the pulley on the compressor so as to change the speed of rotation of the compressor.

Abstract: Auxiliary equipment in a vehicle such as dynamo, fan, pumps etcetera are coupled to an engine by a continuously variable transmission. The pump is connected to the secondary shaft of the transmission, whereas the rest of the equipment is coupled to the shaft 9 via a controllable clutch. Engaging of the clutch takes place with a signal provided by per example a Pitot tube fixed to a secondary pulley of the transmission in dependence on the number of revolutions of the shaft.

Abstract: A continuously variable speed transmission with parallel rotary input and output shaft which respectively carry first and second adjustable sheaves for an endless belt or chain. Each sheave has a first flange which is affixed to the respective shaft and a second flange which is movable axially of the respective shaft toward and away from the adjacent first sheave. A first cylinder and piston unit can receive hydraulic fluid from a first pump to urge the second flange of the first sheave against the adjacent portion of the belt or chain, and the same pump supplies fluid to a second cylinder and piston unit which urges the second flange of the second sheave against the adjacent portion of the belt or chain. A second pump serves to supply hydraulic fluid to a third cylinder and piston unit which is located radially inwardly of the first unit and is operable to change the transmission ratio.

Abstract: An automatic transmission apparatus for vehicles include a continuously variable transmission of belt type, and a control unit supplied with a plurality of data relating to a vehicle. The control unit computes output data on the basis of the input data, and generates control signals for changing a pulley width of the continuously variable transmission of belt type, for changing an effective diameter of the pulley and for substantially continuously controlling the transmission ratio on the basis of the output data. The control unit comprises a control signal generator for deciding whether the vehicle is started or not and for generating a control signal to temporarily narrow the pulley width when it is decided that the vehicle is started.

Abstract: According to a control for a continuously variable transmission for a motor vehicle, in order to avoid a rapid increase in engine revolution speed upon selecting a power mode from an ordinary mode, the reduction ratio of the continuously variable transmission is varied along a third schedule which connects an ordinary shift schedule for the ordinary mode with a power shift schedule for the power mode. The third schedule is expressed as a funtion of time that has pressed since the instant when the power mode has been selected.

Abstract: A hybrid continuously variable transmission includes a gearing mechanism and a continuously variable transmission mechanism which altenatively take over a drive. According to a ratio change control system, the continuously variable transmission mechanism is prevented from shifting operation until a transition from a drive owing to the gearing mechanism to a drive owing to the continuously variable transmission mechanism is completed.

Abstract: A control system for a continuously variable transmission for a motor vehicle has a transmission ratio control valve for controlling the transmission ratio. The transmission ratio is controlled in accordance with a transmission ratio changing rate. At acceleration during low vehicle speed driving, the transmission ratio changing rate is set to a large value so as to quickly increase the transmission ratio.

Abstract: A control system for a continuously variable transmission for a motor vehicle has a transmission ratio control valve for controlling the transmission ratio. The transmission ratio is controlled in accordance with a transmission ratio changing speed. The transmission ratio changing speed is corrected with a coefficient which is determined in accordance with desired transmission ratio changing speed and the difference between desired transmission ratio and actual transmission ratio.

Abstract: In a part-time (selective) four-wheel-drive vehicle, the engine driving power is selectively transmitted to the rear (or front) wheels by way of a transfer clutch which is operated by a hydraulic actuator acting through a rail and a sleeve of the dog clutch and being controllable by a changeover valve operated by a solenoid which is controlled by a four-wheel-drive switch manipulative by the driver.

Abstract: A speed ratio of a continuously variable transmission is controlled by varying the effective diameters of drive and driven pulleys mounted respectively on input and output shafts with a V-belt trained around the drive and driven pulleys. The effective diameter of the drive pulley is increased based on a signal proportional to a vehicle speed and reduced based on a signal proportional to a throttle valve opening degree and a signal proportional to a speed ratio.

Abstract: A control method controls a belt-and-pulley type continuously variable transmission having drive and driven pulleys mounted respectively on input and output shafts, a V-belt trained around the drive and driven pulleys, and an oil pressure source and an oil reservoir operatively coupled to first and second hydraulic pressure chambers for axially moving the movable conical members of the drive and driven pulleys to vary effective diameters of the drive and driven pulleys for thereby controlling a speed ratio. The movable conical members of the driver and driven pulleys are movable in synchronism with each other. The hydraulic pressure chamber of one of the driver and driven pulleys, the effective diameter of which is to become larger at that time, is first brought into communication with the oil pressure source.

Abstract: A control system for a transmission is disclosed. The control system includes a high clutch and a low clutch. When the high clutch is engaged, the torque transmission path through a V-belt type continuously variable transmission mechanism is established, while when the low clutch is engaged, the torque transmission path through a gearing mechanism is established. The same hydraulic fluid pressure as prevailing in a driver pulley cylinder chamber is admitted to the high clutch directly or via a suitable selector valve (a neutral valve).

Abstract: A V-pulley to be used in a belt type continuously variable transmission, which V-pulley comprises a stationary pulley half fixedly mounted to a transmission shaft and a movable pulley half coupled slidably to the shaft via a plurality of rows of ball keys and cooperating with the stationary half to support a V-belt. A plurality of coil springs resiliently biasing the movable half toward the stationary half too impart an initial tension to the V-belt. A hydraulic operating device includes a first hydraulic member fixedly mounted to the shaft and a second hydraulic member disposed on the movable pulley half to define a hydraulic chamber against the first member for operating the movable half by hydraulic pressure fed to the hydraulic chamber. A control valve for controlling the pressure supply to the device.

Abstract: A hydraulic pressure controller is provided between a hydraulic actuator for changing the effective radii of a drive V-pulley mounted on an input shaft and a driven V-pulley mounted on an output shaft and a hydraulic pump is provided for supplying hydraulic pressure to the hydraulic actuator. The hydraulic pressure controller is controlled by an input torque sensor and a speed change ratio sensor, whereby the hydraulic pressure supplied to the hydraulic actuator is automatically controlled in proportion to the input torque received by the input shaft and the speed change ratio between the input and output shafts.

Abstract: An apparatus for controlling the speed ratio of a steplessly variable transmission of an automotive vehicle comprises a belt-pulley type of steplessly variable transmission mechanism, a speed ratio control device for steplessly varying the speed ratio of the belt-pulley transmission mechanism according to speed ratio change schedules of a target engine speed relative to a vehicle speed depending upon engine load conditions, and a drive mode change device for changing the steplessly variable transmission in operation between a power drive priority mode and a fuel economy drive priority mode and changing the speed ratio change schedules to two different patterns, one suitable for the power drive priority mode and the other suitable for the economy drive mode according to the change of drive mode.

Abstract: A control device for controlling the transmission ratio of an infinitely variable transmission of a motor vehicle is disclosed. The transmission ratio is adjustably dependent on the position of a hydraulic control valve which is movable in dependence upon the difference between a predetermined desired engine speed and the actual engine speed. A stop member displaceable in dependence upon the transmission ratio regulates the minimum possible engine speed in dependence thereon.

Abstract: A control for a continuously variable transmission provides an improved transient performance by restraining proportional and integral terms when an error exceeds a predetermined value range. This is effective in suppressing an overshoot in driver pulley revolution speed in approaching to its target speed. This control is provided with a safeguard against break down of a vehicle speed sensor such that the above mentioned restrain is removed when the vehicle speed indicative signal should drop to zero during running of the vehicle.

Abstract: A control system for a continuously variable transmission for a motor vehicle has a transmission ratio control value for controlling the transmission ratio. The transmission ratio is controlled in accordance with a desired transmission ratio. During use of an air conditioner of the vehicle, the desired transmission ratio increases, so that necessary engine power can be obtained. The desired transmission ratio is increased by a larger value in a small transmission ratio range than a large transmission ratio range.

Abstract: A control valve has ports and a spool which has lands and an annular groove between the lands. The land has a plurality of hollow portions at a circumferential edge portion adjacent the annular groove so as to gradually increase the opening area of one of the ports.

Abstract: According to a hydraulic pressure control system for a continuously variable transmission embodying the present invention, a hydraulic fluid pressure supplied to pulleys is increased temporarily during a transient period where the transmission upshifts from a reduction ratio to a smaller reduction ratio as a result of a predetermined movement of a manual selector valve. The level of the hydraulic fluid pressure is allowed to return to the previous low level after the transient period.

Abstract: A hydraulic control apparatus is employed in a stepless transmission in which an endless belt is stretched between and wrapped around a pair of pulleys and the velocity ratio between input and output shafts is changed by varying the width of a groove defined in each of the pulleys. Hydraulic pressure supplied from a hydraulic pressure supply source is reduced to necessary levels by first and second adjusting apparatus, respectively, and then sent ot respective cylinder chambers of the pulleys. A controller controls the hydraulic pressure supply source on the basis of either one of the hydraulic pressures respectively reduced by the first and second adjusting apparatus which is higher than the other so that the supply source generates a hydraulic pressure which is sufficiently high to supply the higher hydraulic pressure, thus reducing loss of power in the hydraulic pressure supply source.

Abstract: Pressure regulating system for use in an automatic transmission including a fluid coupling, a belt drive continuously-variable speed transmission mechanism having an input pulley and an output pulley which are rotatably interlocked with a V-belt and a reduction ratio control system for controlling the reduction ratio of the belt drive continuously-variable speed transmission mechanism. The pressure regulating system includes a regulator valve capable of regulating the discharge pressure of an oil pump to provide a line pressure, a reduction ratio detecting valve and a throttle pressure valve. The reduction ratio detecting valve receives the line pressure and provides a pressure which is proportional to the displacement of the movable flange of the output pulley with respect to the corresponding fixed flange.

Abstract: A belt type continuously variable transmission system which includes: a fluid coupling device for transmitting an output from an engine by use of fluid; a belt type continuously variable transmission device for transmitting an output from the fluid coupling device at a continuously variable transmission gear ratio through a belt; an auxiliary transmission device having a function of shifting an output from the belt type continuously variable transmission device in accordance with the forward reverse running conditions; a reduction gear device for reducing an output from the auxiliary transmission device; and an oil pump device for feeding the hydraulic pressures to various hydraulic pressure components such as a valve body and the like wherein the various devices are connected to one another while preventing the various devices from interfering with one another, whereby proper functions of the various devices are satisfactorily performed and the transmission system as a whole can be made simplified in constru

Abstract: A hydraulic control system for a continuously variable transmission for an automotive vehicle, the transmission having a first and a second variable-diameter pulley provided on respective first and second shafts, a belt connecting the first and second pulleys, and a first and a second hydraulic cylinder for changing effective diameters of the first and second pulleys.

Abstract: A mechanically adjustable variable speed drive includes an electric actuation apparatus which can be controlled by an analog embodiment or a digital circuitry embodiment. A speed change actuator is automatically and mechanically adjustable, such as with a controlled servomotor. A tachometer determines the actual rotational speed of a drive shaft, which is compared in a digital controller with a manually set desired rotational output speed. The digital controller (or an analog circuit in the case of the analog embodiment) controls the servomotor to adjust the mechanically adjustable variable speed drive. An automatic deadband means inhibits driving of the servomotor whenever the tachometer signal and the desired speed setting signal is within a predetermined deadband, which deadband is adaptively changed responsive to various conditions.

Abstract: A hydraulic control system for a belt drive continuously-variable speed transmission comprising a continuously-variable speed transmission means including a primary variable-pitch pulley having a fixed pulley flange fixed to an input shaft and a movable pulley flange adapted to be axially slidable on said input shaft, a secondary variable-pitch pulley having a fixed pulley flange fixed to an output shaft and a movable pulley flange adapted to be axially slidable on said output shaft, and an endless belt interconnecting said primary and said secondary variable-pitch pulleys; and a hydraulic control circuit including hydraulic servomechanisms hydraulically interconnected with the respective movable pulley flanges of said primary and said secondary variable-pitch pulleys for pressing the corresponding movable pulley flanges toward the corresponding fixed pulley flanges, a regulator valve for supplying the pressurized working fluid of a controlled pressure to said hydraulic servomechanisms, and a control valve ca

Abstract: A control system for an infinitely variable transmission has a transmission ratio control valve having a spool for controlling oil supplied to a cylinder of a drive pulley to change the transmission ratio. The transmission ratio control valve has chambers at both ends of the spool. By controlling the pressure of oil supplied to the chambers in accordance with engine operating conditions, the spool is shifted, so that the speed of changing the transmission ratio is controlled.

Abstract: In a belt driven continually variable transmission, the drive ratio is changed by varying the radial position of the drive belt by moving displaceable sheaves of a pulley assembly. A system for actuating the displaceable sheaves includes a ratio control valve supplied with pressurized fluid and connected to a source of ratio control pressure produced by a solenoid actuated valve. An orifice located between the ratio control valve and the hydraulic cylinder in which the displaceable sheave is located has feedback lines located on opposite sides of the orifice. Pressure in the feedback lines produces a differential force on the ratio control valve tending to increase the flow rate to the cylinder when the pressure drop across the orifice decreases.

Abstract: Infinitely variable transmission for a device with an internal combustion engine (67) is provided with an endless transmission member (14) which has been looped over two pulleys, each having a running groove situated between conical pulley halves (2,3 and 8,9 resp.), at least one conical half of each pulley being axially movable through an associated hydraulic cylinder (4,12), also provided with a first control valve (40) for regulation of the fluid pressure in the cylinder (12) of the driven pulley and in the supply line to a second control valve (20), which second valve is intended for the adjustment of the transmission ratio by regulation of the amount of fluid supplied to and discharged from the cylinder (4) of the driving pulley. Devices have been provided for the operation of the first control valve (40) which bring about an increase or a decrease of the fluid pressure in the cylinder (12) of the driven pulley, depending on the movements of the engine block.

Abstract: In a control device in continuously variable transmission system for a vehicle, wherein a belt is racked across a pulley on the input side and a pulley on the output side, an engine power is transmitted through this belt, and an urging force of the belt by one of the pulleys is controlled by a line pressure of a hydraulic cylinder of the pulley, an engine output torque is determined from an engine rotational speed, an intake throttle opening or an intake air flowrate per unit rotation of the engine and engine operation parameters other than said data, and the line pressure is regulated in relation to the so determined value to obtain the proper line pressure as accurately commensurate to the actual output torque of the engine, so that the fuel consumption rate can be lowered to the maximum, avoiding the slips of the belt.

Abstract: A control system for a motor vehicle provided with a continuously variable transmission. The transmission has a line pressure control valve having ports and a spool for controlling the line pressure of oil supplied to a cylinder of a pulley device to change the transmission ratio. When torque of an engine is rapidly increased, the line pressure is increased so as to prevent a belt of the pulley device from slipping.

Abstract: A compact and rugged belt drive mechanism includes a hydraulically controlled actuator located generally between first and second variable pulley assemblies individually having a movable pulley disc and a fixed pulley disc in order to controllably position the movable pulley discs. A drive belt is entrained between the pulley assemblies, and a force-multiplying apparatus including a competitively profiled cam with oppositely inclined ramps and a plurality of roller members engaging the cam serves to automatically adjust tension on the drive belt. The force-multiplying apparatus and an associated plurality of compression springs for applying a preload against the drive belt are operatively associated with only one of the movable pulley discs for simplicity.

Abstract: An infinitely variable transmission in which the pitches of a driving pulley and a driven pulley are variable by means of hydraulic fluid pressure to vary the velocity ratio between the two pulleys. A lower pressure fluid and a higher pressure fluid are created from a hydraulic fluid from a hydraulic fluid supply source, with a constant pressure difference therebetween. The lower pressure fluid has its pressure value varied in response to the velocity ratio. The lower pressure fluid and the higher pressure fluid are selectively supplied to the movable pulley elements of the driving pulley and driven pulley. A hydraulic clutch and a pressure regulating valve are connected together by a hydraulic fluid supply passageway which is selectively closed and opened by a supply control valve. A drain passage is connected to the hydraulic fluid supply passageway to allow hydraulic fluid to escape from the hydraulic clutch when the passageway is closed by the supply control valve.

Abstract: The speed ratio of a continuously variable transmission (CVT) is adjusted in relation to the actual ratio R.sub.a and a desired ratio R.sub.d so that the time required to change the ratio by any multiplicative step is substantially the same regardless of the ratio provided by the transmission. The ratio error E.sub.r is defined according to the ratio R.sub.d /R.sub.a, and the ratio is adjusted at a rate determined in accordance therewith.

Abstract: A control system for a continuously variable transmission has a line pressure control valve having ports and a spool for controlling the line pressure of oil supplied to a cylinder of a drive pulley. A hydraulic circuit is provided for supplying oil to a port of the line pressure control valve so as to shift the spool. A pressure reducing valve is provided in the hydraulic circuit for keeping the pressure in the circuit constant and a control valve is provided in the hydraulic circuit so as to control the quantity of the constant pressure oil supplied to the end of the spool.

Abstract: A hydraulic control system for a continuously variable transmission which has an input and an output variable-diameter pulley, a belt connecting the input and output pulleys, and a pair of cylinders for changing effective diameters of the pulleys. The control system includes a hydraulic source to supply a pressurized fluid for applying first and second line pressure to one and the other of the cylinders via a first and a second line, respectively.