An occupant propelled device having at least one hydraulic cylinder, a platform and a housing. The at least one hydraulic cylinder has at least two chambers in fluid communication. The platform is attachable to the at least one hydraulic cylinder, such that upon movement of the platform a hydraulic fluid is displaced from one chamber to the other chamber. The housing is attachable to the platform at a pivot point and has at least one axle adapted to receive at least one wheel.

FIELD OF THE INVENTION

This invention relates to a system of powering devices that either require, or benefit from, rotational power or torque in their operation. This invention utilizes hydraulic power to convert linear motion into rotational motion. More particularly, this system can be applied to a truck, wheeled platform, or a vehicle, utilizing hydraulic power, and more particularly for a skateboard or skateboard truck, which utilizes hydraulic fluid to power the skateboard by converting linear motion to rotational motion.

BACKGROUND OF INVENTION

Skateboarding is a popular sport and for some is even a means of transportation. One typical problem a skateboarder encounters is the need to propel the skateboard forward for example, when the slope of the terrain is too shallow and does not allow gravity to pull the skateboard and rider down the slope. Typically, the skateboarder will place one foot on the skateboard and utilize the other foot to push or propel the skateboard forward. This pushing motion, however, can become tiresome and may detract from the more pleasurable experience of riding the board with both feet on it.

In addition, skateboards often do not provide a sensation for the rider that is similar to the gains and losses in speed encountered when turning, curving, and straightening ones path when snowboarding downhill or surfing ocean waves due to the requirement to periodically remove one foot from the board to propel the skateboard. Many geographic areas do not have the terrain required to allow gravity to do some or all the work of propelling the skateboard.

Furthermore, many skateboards suffer from distracting wobbles and vibration at higher rates of speed. Thus, the use of the hydraulic system will tend to dampen the vibrations and provide for a much more stable and controlled feeling for the occupant.

Although, there have been innovations in the self-powered skateboard, none of the innovations have utilized a hydraulic system and method of converting linear motion into rotational motion to propel the skateboard forward.

Accordingly, what is needed is a system and method utilizing a hydraulic system to convert linear motion into rotational motion to propel a skateboard forward and provide a sensation similar to snowboarding or surfing without having to put one foot on the ground to propel the skateboard and without the need for gravity or inclined surfaces.

SUMMARY OF THE INVENTION

In one aspect of the invention, an occupant propelled device including at least one hydraulic cylinder having at least two chambers in fluid communication; at least one platform attachable to the at least one hydraulic cylinder at a first connection point and a second connection point, wherein movement of the platform displaces a hydraulic fluid from one of the at least two chambers; a housing attachable to the platform at a pivot point and having at least one axle adapted to receive a wheel, wherein the pivot point is positioned between the first connection point and the second connection point of the at least one hydraulic cylinder; and at least one wheel.

In a further aspect of the invention, an occupant propelled device including at least two hydraulic cylinders, each cylinder having at least one chamber in fluid communication; at least one platform attachable to the at least two hydraulic cylinders at a first connection point and a second connection point, wherein movement of the platform displaces a hydraulic fluid from one of the at least two hydraulic cylinders; a housing attachable to the platform at a pivot point and having at least one axle adapted to receive a wheel, wherein the pivot point is positioned between the first connection point and the second connection point of the at least two hydraulic cylinders; and at least one wheel.

In another aspect of the invention, a hydraulic skateboard including a skateboard deck; at least two hydraulic cylinders, each of the at least two hydraulic cylinders in fluid communication, wherein the skateboard deck is attachable to the at least two hydraulic cylinders such that movement of the skateboard deck displaces a hydraulic fluid from one of the at least two hydraulic cylinders; a pair of skateboard trucks, wherein at least one of the pair of skateboard trucks further comprises at least one hydraulic motor adapted to receive the hydraulic fluid from the at least two hydraulic cylinders, wherein each skateboard truck is attachable to the skateboard deck and configured to be attachable to the skateboard deck at a pivot point, wherein the pivot point is positioned between a first connection point and a second connection point of the at least two hydraulic cylinders and wherein the skateboard deck comprises at least one axle protruding from the truck and configured to receive a wheel; at least one hydraulic motor configured to rotate by displaced hydraulic fluid from one of the at least two hydraulic cylinders creating torque to drive the at least one axle; and at least one wheel attached to the at least one axle of each skateboard truck.

In a further aspect of the invention, a hydraulic skateboard including at least one hydraulic cylinder, having at least two chambers in fluid communication; a skateboard deck attachable to the at least one hydraulic cylinder at a first connection point and a second connection point, wherein movement of the platform displaces a hydraulic fluid; a pair of skateboard trucks, each skateboard truck being adapted to be attachable to the skateboard deck at a pivot point and comprising at least one axle protruding from the truck and configured to receive at least one wheel, and wherein at least one of the pair of skateboard trucks further comprises at least one hydraulic motor adapted to receive the hydraulic fluid from the at least two hydraulic cylinders creating torque to rotate the at least one axle.

In another aspect of the invention, a hydraulic system including at least one hydraulic cylinder having at least two chambers; and a housing attachable to a platform at a pivot point and having at least one axle adapted to receive at least one wheel, wherein the pivot point is positioned between a first connection point and a second connection point of the at least one hydraulic cylinder to the platform; and wherein movement of the platform displaces a hydraulic fluid from one chamber to the other chamber.

In a further aspect of the invention, a hydraulic propulsion system including a hydraulic cylinder having two chambers in fluid communication with one another; a housing connected to a platform at a pivot point; at least one axle extending from the housing; and wherein the hydraulic cylinder is connected to the housing and upon movement of the hydraulic cylinder about the pivot point a hydraulic fluid is displaced from one of the at least two chambers.

In yet another aspect of the invention, a hydraulic system for a skateboard including at least two hydraulic cylinders each having a chamber in fluid communication with one another; and a housing attachable to a platform at a pivot point and having at least one axle adapted to receive at least one wheel; and wherein upon movement of the platform at least one of the two cylinders displaces a hydraulic fluid to the other chamber.

In a further aspect of the invention, a hydraulic system including at least two hydraulic cylinders, each of the at least two hydraulic cylinders in fluid communication; and a housing comprising at least one hydraulic motor configured to receive a hydraulic fluid from the at least two hydraulic cylinders, wherein the hydraulic motor is configured to rotate creating torque to drive an axle; a directional control valve configured to direct the flow of the hydraulic fluid to engage or bypass the hydraulic motor; and an axle surrounding the housing.

The above aspects of this invention are more fully explained in reference to the drawings and general disclosure herein.

DESCRIPTION OF THE INVENTION

FIG. 1shows a perspective view of an occupant-propelled device configured to dampen vibrations and wobbles that a skateboarder can experience at high speeds. The device10comprises at least one hydraulic cylinder100, a housing200having at least one axle220, a platform400, and at least one wheel600.

FIGS. 2 and 3are end views of the device10as shown inFIG. 1.FIG. 2shows the device10at rest with a horizontal platform400.FIG. 3shows the device10not at rest with the platform400dipping to the left. The device10comprises at least one hydraulic cylinder100comprising at least two chambers102. The at least two chambers102are in fluid communication with each other through a single conduit110which connects to an inlet/outlet port103in each chamber102.

As shown inFIG. 2, the at least one cylinder100comprises a semi-circular double-ended-piston-rod having a first connection point112and a second connection point114affixed to the at least one platform400. In this embodiment, the at least one hydraulic cylinder100is preferably a single double-ended-piston-rod-spring-centered hydraulic cylinder100; however, it can be appreciated that other types of cylinder arrangements can be used. Preferably each connection point112,114of the hydraulic cylinder100is attached with suitable fixed connections to the platform400. However, it can be appreciated that the hydraulic cylinder100can be attached to the platform400with suitable pivoting or flexible connections to the platform400. It can also be appreciated that it is not necessary to use a semi-circular hydraulic cylinder and that other cylinder configurations can be used.

The at least one hydraulic cylinders100as shown inFIG. 3is adapted to displace a hydraulic fluid from one of the hydraulic chambers102to the other hydraulic chamber102when compressed, after passing through a housing200via a conduit110which connects the two chambers102. It can be appreciated that the conduit110can be a flexible or rigid hydraulic conduit, which can be located internal or external to the housing200. Additionally, the conduit110can be designed with an adjustable restrictor valve116to dampen or restrict the rate at which the hydraulic fluids flow from one chamber102to the other chamber102. The two chambers102are separated by a movable piston122, which separates the two chambers102of the at least one hydraulic cylinder100from each other. It can be appreciated that the hydraulic fluid can be any suitable liquid or gas including but not limited to water, mineral oil, or oil. It can be appreciated that the hydraulic system could be replaced with a similar pneumatic system using air or other suitable gas as a replacement for the liquids. Pneumatic embodiments of these devices may or may not require fluid or gaseous communication between the chambers102.

Each of the two chambers102further includes a spring-like element106configured to provide resistance within the chambers102within the at least one cylinder100while the hydraulic fluid is being displaced from one chamber102to the other chamber102. Any suitable spring-like or resistive device can be used within or external to the hydraulic chambers102without departing from the present invention.

Gravitational force, centrifugal force and the force derived from the dipping of the platform400to the left or the right or up and down will actuate the hydraulic cylinder100. In operation, one of the chambers102of the hydraulic cylinder100compresses, while the other chamber102of the hydraulic cylinder100expands forcing the hydraulic fluid from the compressed hydraulic cylinder chamber102into the expanding hydraulic cylinder chamber102. The expanding hydraulic cylinder chamber102creates a volume of reduced pressure to suction the hydraulic fluid into the hydraulic cylinder chamber102.

The housing200as shown inFIGS. 1–3is a skateboard truck. However, it can be appreciated that the housing200can be a skateboard truck, or any other desirable enclosure for internal components of the hydraulic system. The housing200is attachable to the platform400at a pivot point210. It is preferable that the pivot point210is approximately equal distance (or symmetrically positioned) from the connection points112,114to the platform400, however, it can be appreciated that the pivot point210can be at a distance that is not an equal distance or centrally located. The housing200further comprises at least one axle220adapted to receive at least one wheel600.

The housing200can further include a conduit110connecting the two chambers102to one another or alternatively, the conduit110can be outside of the housing200. If the conduit110is outside of the housing200, the conduit110can be contained within the hydraulic cylinder100or outside of the cylinder100. It can be appreciated that the device10comprising a single double-ended-piston-rod-hydraulic cylinder100as shown inFIGS. 1–3can be designed without a housing200, wherein the cylinder100further comprises the conduit for flow between the two chambers of the cylinder, at least one axle220and a means for attaching the cylinder100to the deck of the skateboard or platform400.

The platform400as shown inFIGS. 1–3is preferably affixed to each end of a single double-ended-piston-rod hydraulic cylinder100at connection points112,114. The movement of the platform400from a first position to a second position (i.e., side to side, or up and down) causes the at least one hydraulic cylinder100to displace a hydraulic fluid from one of the at least two hydraulic cylinder chambers102to the other hydraulic cylinder chamber102which expands to receive the hydraulic fluid and can dampen or eliminate the vibrations to varying degrees by restricting the size of the fluid conduit which connects the two chambers102, that a skateboarder can experience as a result of the speed of the skateboard.

The at least one wheel600is preferably a skateboard wheel or suitable wheel having a bearing which can be attached to the at least one axle220. The at least one axle220preferably protrudes from truck200and is configured to receive a wheel600. It can be appreciated that the skateboard can be equipped with one hydraulic truck in the front or rear of the skateboard and one standard truck at the opposite end of the skateboard. Alternatively, multiple hydraulic trucks can be mounted on the skateboard.

FIG. 4is an end view of a device10comprising at least two hydraulic cylinders100, each having at least one chamber102, including a circuit diagram illustrating the hydraulic system120. As noted by ISO 1219-1 prime mover symbol, M, the hydraulic system120is powered by the movement of the platform400.

As shown inFIG. 4, the device10comprises at least two hydraulic cylinders100affixed to the platform400at a first connection402and to the housing200at a second connection404. Preferably one end of each hydraulic cylinder100is attached to the platform400with suitable pivoting or flexible connections402.FIG. 4shows a ball joint at the flexible connections402,404; however, the hydraulic cylinders can be attached to the platform400and housing200with any suitable flexible or pivoting connection. The two hydraulic cylinders100are attached with suitable pivoting or flexible connections404to any convenient location on the housing200. Each of the at least two hydraulic cylinders100are in fluid communication with the other via a conduit110.

As shown inFIG. 4, each of the at least two hydraulic cylinders100is adapted to displace a hydraulic fluid from within the cylinder100. For some hydraulic cylinders100, the hydraulic cylinder100will comprise a piston130, a chamber102, and an inlet/outlet port103, and a spring-like element132configured to provide resistance within the chambers102of the cylinder100when the hydraulic fluid is being displaced. It can be appreciated that the hydraulic cylinders100can be hydraulic single acting, double acting, telescopic, pneumatic, and rod-less, with or without springs or any other suitable hydraulic cylinder without departing from the present invention.

The device ofFIG. 4operates based on the gravitational force, centrifugal force and the force derived from the movement or dipping of the platform400to the left or the right or up and down to actuate the hydraulic cylinders100. In operation, one of the hydraulic cylinders100compresses, while the other hydraulic cylinder100expands forcing the hydraulic fluid from the compressed hydraulic cylinder100, after passing through the housing200of the truck and a conduit110into the expanding hydraulic cylinder100. The expanding hydraulic cylinder100creates a volume of reduced pressure to suction the hydraulic fluid into the hydraulic cylinder100.

The housing200as shown inFIG. 4is a skateboard truck. The housing200is attachable to the platform400at a pivot point210. It is preferable that the pivot point210is approximately equal distance (or symmetrically positioned) from each of the at least two hydraulic cylinders100, however, it can be appreciated that the pivot point210can be at a distance that is not an equal distance nor centrally located. The housing200comprises at least one axle220adapted to receive at least one wheel600.

The platform400is affixed to the at least two hydraulic cylinders100. The movement of the platform400from a first position to a second position (i.e., side to side, or up and down) causes the hydraulic cylinders100to displace a hydraulic fluid from one of the at least two hydraulic cylinders100to the other hydraulic cylinder100which expands to receive the hydraulic fluid, which dampens or eliminates the vibrations that a skateboarder can experience as a result of the speed of the skateboard. The degree to which the fluid dampens the vibrations can be engineered by changing the dimensions of the conduit110to be more or less restrictive to fluid flow or by adding an adjustable restrictor valve116.

The housing200comprises at least one axle220adapted to receive at least one wheel600. The at least one axle220preferably protrudes from the housing200and is configured to receive a wheel600. Preferably, the at least one wheel600is a skateboard wheel. The at least one skateboard wheel600is equipped with standard skateboard bearings. It can be appreciated that the skateboard can be equipped with one hydraulic truck in the front or rear of the skateboard and one standard truck at the opposite end of the skateboard. Alternatively, multiple hydraulic trucks can be mounted on the skateboard.

FIGS. 5 and 6show alternative embodiments ofFIGS. 3 and 4, respectively, further comprising at least one hydraulic motor300adapted to receive the hydraulic fluid from either chamber102of the at least one cylinder embodiment as shown inFIG. 3or from either of the at least two hydraulic cylinders100as shown inFIG. 4. The hydraulic motor300comprises at least one rotor310configured to rotate by the displaced hydraulic fluid creating torque to drive the at least one axle220.

The hydraulic cylinders100are adapted to displace the hydraulic fluid from the hydraulic cylinders100when compressed. The hydraulic motor300is adapted to receive a displaced hydraulic fluid from the hydraulic cylinder100or the at least two hydraulic cylinders100, wherein the rotor310of the hydraulic motor300is caused to rotate by the displaced hydraulic fluid creating torque to drive an axle220of a wheel600.

FIGS. 5 and 6include modified circuit diagram for an embodiment of an occupant-propelled device such as a skateboard having a fixed displacement or variable displacement hydraulic motor300.FIGS. 5 and 6show a hydraulic motor300having a pair of drive axles220. The drive axles220preferably comprises at least one axle220that can be disengaged from the motor300, such that the disengaged axle will be fixed and will not rotate. This fixed axle will contain a standard skateboard wheel equipped with standards skateboard bearings. Disengaging one of the drive axles from the motor enables the two wheels to rotate at different rotational velocities, which may be preferable for housings200which may be designed to also steer the device or skateboard. In addition, it can be appreciated that the motor300can have either one direction of rotational torque or two directions of rotational torque. The skateboard may be propelled by the rider in immediate response to the steering of the skateboard, whether turning left or right by providing torque to the drive axle220in response to the compression of the hydraulic cylinder or hydraulic cylinders100located symmetrically across a longitudinal axis of the platform400in the form of a skateboard deck.

The torque can be provided in either one direction of axial rotation or both, depending on the type and construction of the hydraulic motor. In addition, the direction of rotation for motors300with only one direction of torque can be either clockwise or counterclockwise depending on which side of the device10the motor300is located and whether the hydraulic device10is positioned at the front end or back end of the platform400. Although torque may be provided in only one direction, the rotor310, axles220, or the wheels600mounted to them, can spin in either direction.

The hydraulic motor300can be a variable displacement motor, such as vane motors or axial piston motors or any other type hydraulic motor300that can provide variable displacement or fixed displacement capacity. If a variable displacement motor is used, the variable displacement motor is preferably pressure balanced, such that the rider will experience a relatively narrow range of resistive forces when turning, regardless of the speed at which the occupant is traveling on the skateboard. The variable displacement motor allows its displacement capacity to vary in response to the speed of the axial rotation of its internal components305and axles220and to the pressure delivered by the compression of the hydraulic fluid from one chamber102to the other chamber102. It is the intent of this invention's design to allow the rider to feel a relatively consistent feel of resistance, within the inventions nominal range of operation, regardless of the speed at which the skateboard is traveling.

The platform400or skateboard deck as shown in theFIGS. 5 and 6are affixed to the at least one hydraulic cylinder100or the two cylinders100, wherein the platform400is adapted to move from a first position to a second position to displace the hydraulic fluid within the hydraulic cylinders100. The at least one wheel600is attachable to the axle220protruding from either the at least one cylinder100or housing200(FIG. 5) or the housing200(FIG. 6) and configured to provide the device10ameans to move laterally over a surface.

In operation, the device10in the form of a skateboard is propelled forward by the shifting of the bodyweight of a rider of the skateboard. In operation, the rider propels the device10by shifting their body weight to the left or the right. Typically, the skateboard will turn in response to the shifting of the platform from side to side or up and down. However, it can be appreciated that the at least one cylinder100or housing200(FIG. 5) or the housing200(FIG. 6) or skateboard truck can be configured to not turn when the platform400or deck of the skateboard is tilted to the left and right. As a result of the shifting of the rider's bodyweight, the skateboard deck dips to the left or right, respectively, which causes the hydraulic fluid located within the chambers of a cylinder100or the at least two hydraulic cylinders100to flow to the hydraulic motor300. The internal components305within the hydraulic motor300are caused to rotate by the displaced hydraulic fluid creating torque to drive the axle220and the wheels600.

The platform400in the form of a skateboard deck as shown inFIGS. 1–6is composed of fiberglass, metal, plastic, wood, or wood composite or any suitable material for a skateboard deck and may be configured to be constructed in one or more pieces. In addition, the platform400can have variable degrees of stiffness and flexibility to maximize the hydraulic system based on the weight of the rider and the riders skateboarding style, i.e. gradual turns or a more aggressive pumping action of the skateboard deck. It can be appreciated that although the platform400is shown as a skateboard deck, any type of platform400can be used, such that the platform400can be modified for use in moving furniture or other heavy items on a platform400, wherein the apparatus is propelled by a rocking motion. In addition, it can be appreciated that a heavier item preferably would be on a different platform than those that compress the hydraulic cylinders. For example, a stable platform400can be used for the load. Meanwhile, separate rocking or alternating platforms for example a stair climbing type motion, can drive the hydraulic cylinder or cylinders100. Alternatively, the system can be used with a plurality of platforms400, wherein each of the platforms400controls a hydraulic cylinder100as shown inFIG. 7.

FIG. 7illustrates an alternative embodiment of the present invention, wherein the platform400further comprises at least two separate platforms410,420. As shown inFIG. 7, each of the at least two separate platforms400controls a hydraulic cylinder100. Each hydraulic cylinder100is attached to the platform400with suitable fixed, pivoting or flexible connections402. The opposite end of each of the two hydraulic cylinders100is attached with suitable fixed, pivoting or flexible connections404to any convenient location on the housing200. It can be appreciated that the embodiment shown inFIG. 7can be adapted to any of the embodiments described herein. It can be appreciated that these alternate forms of platforms can integrated with any of the embodiments inFIGS. 1–6,9–12, and14.

It can be appreciated that the embodiments as shown in shown inFIGS. 5,6, and7can further comprise a directional control valve500as shown inFIG. 8. The directional control valve500is configured to direct the hydraulic fluid to flow either through the hydraulic motor300or to bypass the hydraulic motor300. The route the hydraulic fluid travels can be a function of the hydraulic pressure at the head of, or the pressure differentials across, the valve500. For example, if the hydraulic pressure is too low or too high, the hydraulic fluid will bypass the motor300, such that the motor's internal components305are allowed to spin freely. It can be appreciated that unless the hydraulic fluid is allowed to bypass the motor300, the motor300may not have a free-spin state, which is desirable for coasting or gliding.

The directional control valve500preferably comprises a pair of tension screws to manually adjust one or more springs510,520to minimum and maximum pressure settings. The minimum and maximum pressure settings define a range within which hydraulic fluids will engage the hydraulic motor300. It can be appreciated that a sensor, a programmable microprocessor or other desirable device for setting a minimum and a maximum pressure range can be used. It can further be appreciated that a switch505can be used to lock the directional control valve500into a position that causes the hydraulic fluid to bypass the motor300. If the switch is used to bypass the hydraulic motor300, the switch effectively becomes an on/off switch for the motorized functionality of the invention. If pressures created by the compression of the hydraulic cylinder are within the manually adjusted operational range of the directional control valve500, the hydraulic motor300will be engaged and may impart torque to the drive axle220of the hydraulic motor300.

The hydraulic system120preferably provides a continuous variable transmission through the use of a variable displacement hydraulic motor rather than a fixed displacement hydraulic motor, such that at rest, the variable displacement hydraulic motor300is spring centered and has no volumetric displacement capacity and allows the internal components to spin freely without providing torque. At slower speeds, the motor's300volumetric capacity is increased towards its maximum by internal hydraulic pressure acting against the spring force to allow some relatively larger amount of fluid within the hydraulic system to pass through the variable displacement hydraulic motor300with fewer rotations of the motor's internal parts. As angular velocity of the drive axle220increases, the motor's volumetric per rotation displacement capacity automatically decreases and lets a relatively smaller amount of the fluid in the closed hydraulic system to pass through per rotation. Regardless of the speed at which the skateboard is traveling, when the motor300is engaged, a similar amount of hydraulic fluid passes through the motor300per unit of time and the motor300will continue to provide torque due to the automatically varying displacement capacity of the motor. Torque will diminish as the displacement capacity approaches zero at higher speeds, effectively defining the upper nominal range of operation at faster velocities. At zero displacement capacity the hydraulic motor300imparts no torque, allows no fluid to pass through, and the motor's internal components305will spin freely within the motor housing.

Torque is preferably provided by the hydraulic motor300in both directions of axial rotation clockwise and counterclockwise, when they are engaged by an appropriate amount of hydraulic pressure. Alternatively, the hydraulic motor300can provide torque in only one direction of axial rotation, clockwise or counterclockwise, depending on the which side of the truck the motor300is located and the position of the trucks relative to the front or leading end of the skateboard. Additionally, each hydraulic motor300can have a no-torque resting state, which allows the drive axles220to rotate freely when the hydraulic pressures are not appropriate to engage the hydraulic motors300.

The hydraulic motor300can further comprise a motor bypass valve285as shown in half of the motors300detailed inFIGS. 15 and 16, which alternately connects and disconnects direct fluid communication between inlet chamber286of the hydraulic motor300and the discharge chambers288of the hydraulic motor300. The bypass valve285enables continuous fluid communication between the inlet and discharge chambers of the hydraulic motor300when the remaining fluids in the hydraulic system120are bypassing the hydraulic motor300. The bypass valve285allows the hydraulic motor300to retain a non-zero displacement capacity in the motor's300free-spin state. When the bypass valve285is open, allowing fluid communication between the inlet286and discharge288chambers of the motor300, the motor300does not have to return to a spring-centered zero displacement capacity state each time the motor300is disengaged from the system120or each time the cylinder100cycles between the compression and expansion phases. Rather, the motor300can retain non-zero displacement capacity, which the motor300may have adopted at the end of its last cycle of engagement by pressured hydraulic fluids. The next time the motor300returns to a state of engagement by pressurized fluids, the displacement capacity will be waiting at or near that level established during the prior cycle of engagement.

The bypass valve285also prevents the need for the displacement capacity to reset to zero during each cycle of engagement. The bypass valve285features will be especially effective when the axles retain a relatively constant state of angular velocity. So long as the angular velocity of the axles remains relatively constant, the motor's displacement capacity should remain relatively constant. The net effect of the bypass valve285is to prevent wear and tear on moving parts and to prevent the possibility of a jerky feel to the inventions function as the motor300would otherwise have to constantly cycle between zero displacement capacity when disengaged and a non-zero displacement capacity when the motor300is engaged.

The directional control valve500and its manually adjusted tension springs510,520define the pressure range within which hydraulic fluids will engage the hydraulic motor300and generate non-zero displacement capacity within the motor and torque in the drive axle. Below or above this manually adjusted pressure range, the directional control valve500will divert hydraulic fluids and bypass the hydraulic motor300. The pressure range within the directional control valve500is adjusted manually by adjusting a maximum pressure spring510and a minimum pressure spring520. (SeeFIG. 8). At rest the directional control valve500is spring controlled by the maximum pressure spring510, which provides greater force than the minimum pressure spring520. Compression of the hydraulic cylinder300causes the hydraulic fluid to move from the hydraulic cylinder100to the directional control valve500.

The directional control valve500has two end states, both of which cause the diversion of hydraulic fluids around the hydraulic motor300, and one, or a continuum, of intermediate state that causes hydraulic fluids to engage the hydraulic motor300. Below minimum pressures, defined by the manually adjusted tension on the minimum pressure tension spring520, the hydraulic fluid does not engage the motor since the fluid is diverted through a bypass conduit240and around the hydraulic motor300.

Alternatively, when hydraulic pressures at the directional valve500exceed maximum pressures defined by the manually adjusted settings of the maximum pressure tension spring510, the hydraulic fluid does not engage the motor300since the fluid is diverted around the hydraulic motor300. Between the minimum and maximum pressures defined by the manually adjusted settings of the minimum pressure tension spring520and the maximum pressure tension spring510, fluids are directed by the directional control valve500to the hydraulic motor300. It can be appreciated that it is not necessary to have an upper pressure range setting for this invention to function as designed. The upper pressure range setting for the direction control valve500is a safety feature that disengages the motor300if there is a system malfunction which involves excessive system120pressures. Drastically reducing the spring tension of the upper pressure setting can also function as a means of manually disengaging the ability of the system to provide torque while riding the skateboard.

As shown inFIGS. 5,6, and7, the hydraulic system120comprises a delivery conduit235, the bypass conduit240, a motor conduit245, and a return conduit280. In operation, the hydraulic fluid exits the hydraulic cylinder100through an exit port320into the delivery conduit235. In the multiple cylinder embodiments ofFIGS. 6 and 7, the delivery conduit235and the return conduit280preferably have sections with flexible hose or conduits to accommodate for the tilting or movement from side to side of the platform400, cylinders100, and housing relative to each other. However, it can be appreciated that any suitable conduit material can be used or that other fluid delivery routes between the cylinders and the housing can be accomplished. In the one cylinder embodiment shown inFIG. 5, the two chambers102of the cylinder100are preferably incorporated within the housing200of the hydraulic truck, such that the fluid communication occurs entirely within the housing200. The delivery conduit235and the return conduit280are preferably contained entirely within the housing200, as there is no differential motion required between the semi-circular housing of the single cylinder and the truck housing200.

In the at least two hydraulic cylinder100embodiments shown inFIGS. 6 and 7the hydraulic fluid flows from the hydraulic cylinders100through the exit port320and enters the housing200through an entrance port325into the delivery conduit235. In the single cylinder embodiment shown inFIG. 5there is not a need for the entrance port325, which is designed to receive fluid delivered through a ball joint coupling404. The delivery conduit235in all embodiments ofFIGS. 5,6, and7preferably has a first check valve265, which prevents the hydraulic fluid from flowing into the hydraulic cylinder100through the delivery conduit235. The hydraulic fluid then flows through the delivery conduit235from one cylinder chamber102to a junction of the delivery conduit235from the other or cylinder chamber102and a continuation of these conduits235to the directional control valve500. Fluid from both delivery conduits235can only travel to the directional control valve500, which directs the hydraulic fluid through the motor conduit245to the hydraulic motor300or to the bypass conduit240.

The fluid passing through the hydraulic motor300exits the motor through return conduit280. The fluid bypassing the hydraulic motor through bypass conduit240joins the return conduit280. Fluid in the return conduit can flow in only one direction, which is controlled by check valves250and275. Check valve250specifically prevents the backflow of fluids through the hydraulic motor300. Check valve260prevents the backflow of fluids in the bypass conduit240through the directional control valve500.

The hydraulic pressure in the delivery conduit235, which is located upstream of the directional valve500, provide pressure assistance to the minimum pressure tension spring520, and directs force against the tension provided in the maximum pressure tension spring510. The pressure range within which the directional control valve500will direct fluid to engage the hydraulic motor300can be adjustable by manually adjusting the tension on the springs510,520via screws or knobs or any other suitable controlling mechanism whose controlling elements may be exposed on the exterior of the truck housing and attached to tension springs510,520. When the combination of upstream fluid pressure in conduit235and the minimum spring520pressure just exceeds the maximum spring510pressure, the directional control valve500will shift to an intermediate state referred to as the working pressure range. Within the working pressure range fluid will flow through motor conduit245to the hydraulic motor300.

Outside of working pressure range, hydraulic fluids will bypass the motor300through the bypass conduit240, and a free spin state will be established within the motor300and axles220. In this embodiment, the hydraulic fluid discharged through the hydraulic motor300or bypassed around the hydraulic motor300enters the return conduit280. The hydraulic fluid is suctioned into the opposing hydraulic cylinder100located on the opposite side of the housing, in a symmetrical position around the centerline of the skateboards longitudinal axis through the return conduit280. Return conduit280splits at a junction and allows fluid to flow to either of the two hydraulic cylinder chambers102. The route the fluid takes will be determined by the compression and expansion phases of the hydraulic cylinders100. Hydraulic fluids in return conduit280will flow to the hydraulic cylinder chamber102, which is expanding. Fluids within the hydraulic cylinders100are prevented from flowing backwards through return conduit280by a pair of check valves275. Alternatively, a single directional check valve276(SeeFIG. 7) located at the junction that splits the return conduit280into two paths can replace the pair of check valves275. The return conduit280returns the hydraulic fluid to the hydraulic cylinder100through an entrance port330.

The system120preferably has one direction of fluid flow into the hydraulic motor300, such that hydraulic fluid collected in the return conduit280and returning to one of the at least two hydraulic cylinders100is prevented by return check valves250,260from flowing back through the motor300or through the bypass conduit240in the opposite direction, respectively. It can be appreciated that the system120can be designed to operate by allowing fluids to flow both directions through the motor100. In the current embodiment the motor300allows fluids to pass through in only one direction such that the inlet286and discharge ports288on the motor300cannot be interchanged, wherein the fluid flow is into the inlet port only. In this embodiment the motors can be single-rotation or bi-rotational motors, wherein the torque can be provided in only one or in both direction of axial rotation, respectively. If the hydraulic motor is not engaged it will have a zero-displacement capacity (unless the motor is equipped with bypass valve285) and will be in a free-spin resting state.

Check valves275prevent the back flow of fluid from one hydraulic cylinder chamber102to the other hydraulic cylinder chamber102. It can be appreciated that although the flow of hydraulic fluid is through conduits, other suitable devices can be used for the flow of the hydraulic fluid in the hydraulic system120.

The embodiments as shownFIGS. 5,6, and7can incorporate the full suite of types of motors as shown inFIG. 15: single or dual directions of torque, single or variable displacement, single or dual axle. Alternatively if a fixed displacement motor is implemented, the system should include bypass valve285(seeFIGS. 15 and 16) but could be designed without it.

FIGS. 9 and 10illustrate circuit diagrams for a further embodiment having multiple motors and multiple directional control valves. Functionally it operates much like the prior embodiment referencingFIGS. 5 and 6with the distinct addition of two hydraulic motors300and directional control valves500. In this embodiment, the rider propels the skateboard in immediate response to the steering the device either left or right. This embodiment can have one drive direction forward and can free spin in the other direction or the embodiment can have two directions of rotation. It can be appreciated that the hydraulic motors300can be any suitable types of hydraulic motors. In addition, it can be appreciated that if the hydraulic motors are variable displacement motors, the motors300may or may not include the bypass valve285. If the motors300are fixed displacement motors, then the bypass valve285is preferably included.

As shown inFIGS. 9 and 10, the hydraulic motors300are located within the housing200or skateboard truck, and provide torque to the drive axles220. Throughout this description there are dual and symmetric functional elements one directional control valve, motor, conduits drives and controls one axle, the other set of symmetrical components controls the other axle. Dual components allow the system to be propelled by one or the other motors300and allow the dual components to have different angular velocity for opposite wheels at the same time. Variable angular velocity in opposite wheels provides the device10with the ability to drive axles220which, during steering or turning, are rotating at different rotational velocities. The hydraulic motors300can be engaged in immediate response to the compression of one or the other hydraulic cylinders100. The two hydraulic cylinders100are located symmetrically across the longitudinal axis of skateboard deck.

In the single cylinder embodiment shown inFIG. 9the delivery conduit235from one hydraulic cylinder chamber102can be connected to either one or the other directional control valves500. Regardless of which directional control valve500the delivery conduit235is connected to for a given cylinder chamber102, the return conduit280must lead to the opposite cylinder chamber102. The difference between these two alternative connection schemes determines whether the wheels on the outside of the turn or the wheels on the inside of the turn may be engaged by its respective motor300. Conceivably, if the wheels600and axles220connected to the motors300on the inside of the turn provide the torque; the vehicle may achieve greater speeds than the alternative connection scheme.

FIGS. 1 and 12illustrate a circuit diagram for another embodiment having a delayed-drive system. The system comprises at least two motors300, at least two directional control valves500and a piston accumulator800. In this embodiment, the rider propels the skateboard in a delayed and indirect response to the steering of the skateboard, whether turning left or right. In prior embodiments the compression of hydraulic cylinders created pressures that, when in a user defined range of pressure, was in direct fluid communication with the hydraulic motors that propelled the skateboard. In the prior embodiments the skateboard was propelled in immediate response to the compression of the hydraulic cylinders. In this present embodiment the skateboard is propelled in delayed response to the steering of the skateboard.

The delayed response provides a sensation for the rider that is more similar to the gains and losses in speed encountered when turning, curving, and straightening ones path when snowboarding downhill, or surfing ocean waves. In these sports, the motion of turning tends to slow the rider and speed is typically gained when straightening the path of travel when the radius of curvature of the turn increases. The current embodiment is designed to provide a similar sensation.

Functionally it is proposed that the torque provided by the hydraulic motor300in the present embodiment will have less force to overcome than prior embodiments and that greater speeds will be possible as a result. As one hydraulic cylinder100compresses, the radius of curvature of the skateboard's path of travel decreases. The fluid displaced by compressed hydraulic cylinder100is forced, under pressure, into storage, within a functional unit herein referred to as a piston accumulator800. At that moment in time when the turning motion of the skateboard has its shortest radius of curvature, the centrifugal and gravitational loads of the rider are peaking for that cycle of compression within the turn. Following this peak the rider begins to straighten his turn, expands the formerly compressed hydraulic cylinder100and “unweights” his centrifugal and gravitational loads. Skateboard decks or platforms400with greater elasticity will accentuate this unloading effect. It is in this next moment following the peak of the centrifugal loading that the piston accumulator800releases the stored hydraulic pressure stored within it. This stored hydraulic pressure is able then to act upon a system whose external loads are being lightened, thereby offering the potential of greater speeds, effectively providing a bouncy, sling-shot feeling of propulsion as the rider comes out of his turns. It is this delayed-drive response that will provide a more natural feel similar to that of snowboarding or surfing. Potential energy to propel the skateboard is created when the skateboard is turned either left or right. This potential energy is stored in a device referred to herein as a piston accumulator800located in the hydraulic circuits between the hydraulic cylinders100on one side and the directional control valves500on the other side. Energy is stored in the piston accumulator800during the compression of one hydraulic cylinder100in a multiple cylinder embodiment or one of the two chambers102in the single hydraulic cylinder100embodiment and is retained there until the radius of the turn begins to increase when the path of the skateboard begins to straighten coming out of the turn or when the compressed hydraulic cylinder100begins to expand. The potential energy is then released from the piston accumulator800and made available to one of the hydraulic motors300.

As illustrated inFIGS. 11 and 12, the delayed-drive system preferably comprises two directional control valves500, two hydraulic motors300, two axles220, at least two wheels600, and a piston accumulator800. The delayed-drive system can be used with the single cylinder100or the at least two hydraulic cylinder100embodiments as shown inFIGS. 1,5–7,9, and10. In operation, the system incorporates a piston accumulator800with a hydraulic motor300comprising a fixed displacement or a variable displacement configuration. In addition, the hydraulic motors300preferably provide torque in one direction of rotation or both directions of rotation. Preferably a hydraulic motor300is positioned on each side of the truck housing200. A rider stands on the skateboard and shifts their body weight left or right to turn the skateboard. The skateboard deck dips to the left or right, respectively, in response to the shift in the rider's weight. Gravitational force, centrifugal force and the force derived from the dipping of the skateboard left or right will actuate hydraulic cylinders100. The hydraulic cylinder100on one side compresses and the other hydraulic cylinder100on the other side simultaneously expands the same amount. This pattern of compression and expansion of the two hydraulic cylinders100alternates back and forth as the skateboard is turned repeatedly from left to right.

As illustrated inFIGS. 11 and 12, two hydraulic motors300, located within skateboard truck200, provide torque independently to drive two different axles220. Each hydraulic motor300drives one axle220. Throughout this description there are dual and symmetric functional elements. The hydraulic motors300can be engaged in delayed and indirect response to the compression of one or the other hydraulic cylinders100. The compression of hydraulic cylinder chamber102builds potential energy within a piston accumulator800. The potential energy stored in the piston accumulator800drives the hydraulic motors300.

FIG. 13shows the piston accumulator800comprising two dual-chambered, double-ended-piston-rod, spring-centered hydraulic cylinders880, wherein each hydraulic cylinder comprises at least two inlet ports860,870, two outlet ports865,875, one for each of the two chambers of each double ended hydraulic cylinder880, a directional control valve850, and a series of conduits through which hydraulic fluids are directed. It can be appreciated that there are other methods of designing an element herein referred to as a piston accumulator that have the same or similar function of alternately storing and releasing hydraulic potential energy to a hydraulic system without deviating from the present invention. In operation, fluids accumulating in the expanding chamber of the double-ended-piston-rod cylinder880are stored under pressure and prevented from escaping the chamber through exit port865by the piston accumulator's directional control valve850, so long as the compressing hydraulic cylinder100continues its compression phase. The directional control valve850is, itself, controlled by the compression and expansion of hydraulic cylinders100. During the compression phase of hydraulic cylinder100fluids within conduit815force the directional control valve into one of two end states. In the first end state, the piston accumulator's directional control valve850allows the communication of fluids between one of the two double-ended-piston-rod cylinders880in the piston accumulator800and one of the directional control valves500. During this same initial end-state of the piston accumulators directional control valve500, fluids are prevented from communicating between the other double-ended-piston-rod cylinders880in the piston accumulator800and the other directional control valve500.

At the point the rider begins to straighten out of the turning skateboards minimum radius of curvature, the compressed cylinder100begins to expand. At this moment the piston accumulator's800directional control valve850shifts to its second of two end states. In this second end state the roles of the two double-ended-piston-rod hydraulic cylinders880reverse. The double-ended-piston-rod hydraulic cylinder880that formerly was storing pressurized fluid is now releasing this stored energy through exit port865through conduit820through the piston accumulator's directional control valve850to delivery conduit830to directional control valve500. This fluid either passes through the hydraulic motor300or bypasses the hydraulic motor300and returns through return conduit280back to the piston accumulator's800directional control valve850. This returning fluid passes through the piston accumulator's800directional control valve850through conduit840and then through the inlet port870on the expanding side of the double-ended-piston-rod hydraulic cylinder880.

In operation, the chambers within the two double-ended-piston-rod hydraulic cylinders880function very much like the chambers of a heart. A plurality of valves allows the hydraulic fluid to flow into the piston accumulator800within the chamber in a single direction. The valves allow the hydraulic fluid to escape with the heart compresses and forces the fluids into the circulatory system. Once the compressed hydraulic cylinder100begins to expand, the potential energy stored within the first piston accumulator is made available to engage one of the hydraulic motors and to propel the vehicle. At the same time energy is released from one of the chambers of the piston accumulator800on one side of the skateboard truck, the other chamber of the piston accumulator800is being stored with potential energy from the compression of the other formerly expanding now compressing hydraulic cylinder100.

As shown inFIG. 13, the hydraulic fluid is delivered from the hydraulic cylinder or cylinders100through the delivery conduit235to the piston accumulator800. The hydraulic fluid exits the piston accumulator through a directional control delivery conduit830, which connects the piston accumulator800to the directional control valve500. As with the other embodiments, the hydraulic fluid is delivered to the motor300via conduit245. With a piston accumulator800, the return conduit280terminates at the piston accumulator800and a return conduit890connects the piston accumulator to the hydraulic cylinders100.

In the single cylinder embodiment shown inFIG. 11the delivery conduit830from the piston accumulator800can be connected to either one or the other directional control valves500. Regardless of which directional control valve500the delivery conduit830is connected to, the return conduit280must lead to the appropriate connection on valve850such that fluid passing through one direction control valve500returns to the same double ended piston rod cylinder880from which it derived. The difference between these two alternative connection schemes determines whether the wheels on the outside of the turn or the wheels on the inside of the turn may be engaged by its respective motor300. Conceivably, if the wheels600and axles220connected to the motors300on the inside of the turn provide the torque; the vehicle may achieve greater speeds than the alternative connection scheme.

The directional control valve500directs the hydraulic fluids through the hydraulic motor300or to the bypass conduit240. As with the other embodiments as shown inFIGS. 5–10, the route the fluid travels will be a function of the hydraulic pressure at the head of the directional valve500. If pressures are too low or too high the fluid will bypass the motor300. If pressures are within the manually adjusted operational range, the hydraulic motors will be engaged and impart torque to the drive axle of the hydraulic motor300.

In a two-cylinder embodiment, compression of either of the hydraulic cylinders100will cause hydraulic fluid to discharge from the hydraulic cylinders100through a discharge port320through the delivery conduit235to the piston accumulator800. Check valves250,260, and275prevent fluid from flowing the wrong direction in the conduits235,240,245,890and280, the hydraulic motors300, directional control valve.

FIGS. 14Aand B are alternative embodiments of a device10comprising a single wheel600. The hydraulic circuitry of this embodiment may be identical to that shown inFIG. 5,6, or7. It can be appreciated that the rotational motor need not drive a wheel, but may drive any axle or rotor of a device that requires rotational force, velocity or torque. The device10comprises at least one hydraulic cylinder100, a hydraulic motor300, a directional control valve500and a wheel600. InFIGS. 14Aand B, the hydraulic motor300and directional control valve500are located adjacent to or within the wheel600. As shown, the wheel600surrounds the axle220.

FIGS. 14A and 14Bare single wheeled600devices comprising two hydraulic cylinders100, a hydraulic motor300and a directional control valve500positioned within the interior of the wheel600. It can be appreciated, as in other embodiments of the device10that the system can be constructed with a single hydraulic cylinder.

As shown inFIGS. 14A–Bthe hydraulic device10comprises at least two hydraulic cylinders100attachable to a wheel600having a hydraulic motor300located therein. The hydraulic skateboard comprises a platform400, at least two hydraulic cylinders100, and a hydraulic motor300located within at least one wheel600. It can be appreciated that any suitable connection between the hydraulic cylinder100and the platform400can be used and that any type of hydraulic or pneumatic cylinder can be used.

It can be appreciated that the radial load on the internal components of the motor can be minimized by the extension of the axle220to wrap around or surround the housing200of the motor300. In this situation, bearings222can be used between the housing200and the wrap-around axle220to bear the load and significantly reduce radial loading on the axle200. This aspect of wrapping the axle220around the housing200can be used on any ofFIGS. 1–14or any hydraulic motor300for any function to reduce the radial loads.

FIG. 15shows a reference table of potential motors that could be used for the hydraulic motor300and shown inFIG. 16. Column1includes a variety of fixed displacement motors, column2includes variable displacement motors, column3includes fixed displacement motors with bypass valve285, and column4includes variable displacement motors with bypass valve285. Five rows are included within Table 15 andFIG. 16. Row A shows the general ISO 1219-1 hydraulic circuitry for motors without specification of details of the motor type. Row B shows single-axle/single-torque-direction motors, Row C shows single-axle/bi-directional-torque motors, Row D shows dual-axle/single-torque-direction motors, and Row E shows dual-axle/bi-directional-torque motors. It can be appreciated that each of the hydraulic motors can be replaced with pneumatic motors and the hydraulic system120can be replaced with a similar pneumatic system without departing from the present invention.

FIGS. 16A–16Tis a series of ISO 1219-1 hydraulic circuit diagrams showing many different hydraulic motors referenced by Table 15 that can be used in any of the embodiments as shown inFIGS. 5–7,9–12,14. It can be appreciated that other types of motors can be used for the motor300other than those shown inFIGS. 15 and 16without departing from the present invention. It can be appreciated that the motor300can be either hydraulic or pneumatic without departing from the present invention.

In addition, the devices and skateboards as shown amongFIGS. 1–14can be equipped with one hydraulic truck and one standard truck, or with two hydraulic trucks. In addition, in an alternate embodiment, the hydraulic motors including any torque generating mechanisms can be entirely located within the skateboard wheel rather than within the truck, enabling the hydraulic motorized wheels on any standard skateboard trucks.

The devices or skateboards as shown amongFIGS. 1–14also can include an on/off switch configured to allow the system to operate in two different modes. In the first mode or “off” mode, the hydraulic system does not engage the motor and wheels, such that the wheels are in a free spin mode. In the second mode or “on” mode, the hydraulic system engages the motor under the user defined pressure ranges.

FIG. 17shows a cross section of an alternative embodiment of the device10as shown inFIGS. 1–3,5,9, and11. The device10comprises a standard or hydraulic skateboard truck housing200configured to enable the adjustment of the pitch angle, phi, of the plane of rotation of truck housing200as the truck housing200pivots about pivot point210. When the angle phi is zero, the plane of rotation of the truck housing200as it rotates around pivot point210is vertical. In this end state the truck will not turn left or right in response to the dipping of the deck400to the left or right. In this end state, hydraulic cylinders100may engage the hydraulic motors, but the skateboard will travel in virtually a straight path. As the angle, phi (φ), is adjusted to larger angles, the plane of rotation of the truck housing200as it pivots around pivot point210will deviate from vertical. The larger the angle phi, the more responsive the steering of the skateboard will become to a given dipping motion of the skateboard from the first position to the second position. The occupant can manually adjust the angle, phi (φ), to suite his preferences in the responsiveness of the skateboard's steering to a given change in position (dip) of the skateboard's deck. The truck housing200can be attached to the platform400by a support plate450. It can be appreciated that any of the embodiments as shown inFIGS. 1–14can utilize the pivoting member480as shown inFIG. 17.

It can be appreciated that the pivoting member480can be manually adjustable to fix the angle phi (φ) to any desired position by suitable connection490. Alternatively, the pivoting member480can comprise a sensor and processing unit to automatically adjust the angle, phi (φ), as a function of the rotational velocity of the axles220.

It can be appreciated that any of the devices10as shown amongFIGS. 1–14can further comprise a hydraulic braking system. The hydraulic braking system comprises a hydraulic brake, which clamps onto or presses against the drive shaft of the motor axle220or any other rotating elements of the hydraulic truck300, axle220or wheel600. It can be appreciated that the hydraulic braking system can be used in both the “on” and “off” modes. The hydraulic braking system can be activated by a hand held control; a foot brake located on the skateboard deck400, or other suitable device for activating the braking system.

In an alternative embodiment, the braking system is controlled by a brake pad or lever located on the platform400or skateboard deck. The brake plate or lever rotates about a vertical axis to actuate the hydraulic braking system. In operation, the rider can position his or her trailing foot on or next to the brake plate or lever and upon a twist of the foot; the brake plate rotates sending an impulse to the hydraulic braking system. The hydraulic braking system slows the skateboard and provides the rider with a sensation of a stopping or slowing motion.

Although the platform400has been shown to be a skateboard deck, it can be appreciated that the platform can be any type of platform such as a plain deck for moving furniture and other items, or an in-line skate where the wheels with a flat footprint remain in contact with the road and the hydraulic pressure created by the inline boot leaning from left to right and vice-versa creates a linear hydraulic pressure that is converted to rotational force within each of the in-line skates.

The hydraulic system can be applied to other human powered devices that convert energy generated by compressing and expanding single or multiple hydraulic cylinders into rotational energy via hydraulic motors. Such as motors to drive pumps, pottery wheels, wheeled equipment to move office or work equipment, hand trucks, or any device that can benefit from the rotational energy, such as sewing machines or ice cream makers. In addition, it can be appreciated that the system120can be incorporated into an inline skate, roller skate, or any device comprising a plurality of wheels.

While the invention has been described with reference to the preferred embodiments described above, it will be appreciated that the configuration of this invention can be varied and that the scope of this invention is defined by the following claims.