Abstract: A final drive assembly is used to support a track chain on a track type machine. The final drive assembly includes a sprocket hub mounted for rotation on a fixed hub. A seal is positioned between the fixed hub and the sprocket hub. The fixed hub and the sprocket hub define a seal protection passageway that extends between an outer surface and the seal. The seal protection passageway includes a labyrinth located between an annular attachment flange and the seal along a rotation axis of the sprocket hub. The outer surface includes a valley between a sprocket mount of the sprocket hub and a machine mount of the fixed hub. The seal protection passageway opens at a greater radius than a minimum radius of the valley.

Abstract: A mobile robot includes a robot chassis having a forward end, a rearward end and a center of gravity. The robot includes a driven support surface to propel the robot and first articulated arm rotatable about an axis located rearward of the center of gravity of the robot chassis. The arm is pivotable to trail the robot, rotate in a first direction to raise the rearward end of the robot chassis while the driven support surface propels the chassis forward in surmounting an obstacle, and to rotate in a second opposite direction to extend forward beyond the center of gravity of the robot chassis to raise the forward end of the robot chassis and invert the robot endwise.

Abstract: A tracked vehicle, particularly a piste grooming vehicle, comprising a chassis frame and at least one sprocket for a track is characterized in that the sprocket has limited movement between a working position—in which the sprocket protrudes beyond the chassis frame—and a transit position in which the sprocket is located at least partially, preferably totally, within the width of the chassis frame.

Abstract: An articulated amphibious vehicle includes a boat in the front and a rear propulsion unit pivotally connected by an articulation mechanism to the boat. The rear propulsion unit comprises an engine mechanically coupled to a pair of drive tracks for propelling the vehicle. Steering and throttle devices are provided in the boat to enable the operator to turn and power the rear propulsion unit, to thereby steer and control the vehicle. The articulated amphibious vehicle can travel over water, snow, ice, marsh, bogs, swamp, soft wet terrain or even hard terrain (preferably by adding wheels to the boat). Because it can traverse such a wide variety of environments, this “track boat” is more versatile than conventional air boats or conventional all-terrain vehicles.

Abstract: The present invention provides track assemblies and a method that allow bringing the contact patch towards the inside (the outside) of the suspension arm, by providing a asymmetric track assembly, either by lowering at least one inside (outside) support wheel relative to the remaining support wheels, or by using a belt that comprises, transversally, at least one first profile on the outer (inner) side thereof lower than a second profile on an inner side thereof.

Abstract: A track link connector is disclosed herein that includes an elongate, substantially cylindrical body having a length dimension and including a substantially annular exterior surface and first and second opposing end portions. The track link connector further includes a textured region extending less than 360 degrees around a circumference of the exterior surface of the body at one of the end portions thereof.

Abstract: A robotic vehicle including a chassis having front and rear ends, an electric power source supported by the chassis, and multiple drive assemblies supporting the chassis. Each drive assembly including a track trained about a corresponding drive wheel and a drive control module. The drive control module including a drive control housing, a drive motor carried by the drive control housing and operable to drive the track, and a drive motor controller in communication with the drive motor. The drive motor controller including a motor controller logic circuit and an amplifier commutator in communication with the drive motor and the motor controller logic circuit and is capable of delivering both amplified and reduced voltage to the drive motor from the power source. In one instance, the drive control module is separately and independently removable from a receptacle of the chassis as a complete unit.

Abstract: Embodiments of an all-terrain vehicle for ski track setting, military applications, gardening, etc are described herein which include a rear section having a power train and a first set of drive wheels coupled to the power train so as to be driven thereby, a front section having a drive train and a second set of wheels coupled to the drive train so as to be driven thereby; and a universal coupler that attaches the front and rear sections together and that allows free controlled movement therebetween. The drive train of the front section is coupled to the power train so as to be driven thereby. The front section includes a passenger compartment having user controls therein. Tracks are mounted on both set of wheels.

Abstract: A method and apparatus is disclosed, for construction and operation of an all terrain polymorphic tracked vehicle. The invention improves on the prior art by providing a mechanism whereby it is possible to vary the shapes of the tracks during operation of the vehicle. This capability facilitates negotiating obstacles and rough terrain, enables such vehicles to climb stairs or similar obstacles, and also enables self leveling of the vehicle on inclined terrain.

Abstract: The remote controlled utility vehicle provides a substantially all purpose vehicle for carrying a plethora of personal items and needs. The floor contains a plurality of closable storage compartments and also numerous tubular holders for items like umbrellas and fishing poles. The removable rails help contain any cargo, and the side rails provide flip up solar panels. Most beach and like outings see substantial sunshine. The solar panels can therefore power the apparatus without need of the charging port, which might be used elsewhere in preparation of apparatus uses. The separately controlled drive wheels are linked to rear free wheels and provide, together, treaded track power to negotiate even difficult and especially sandy terrain. Positioning the drive wheels in front features best propulsion and steering characteristics, with treaded tracks providing excellent traction. Flip down cup holders provide convenience, as does multidirectional lighting.

Abstract: A robotic vehicle (10,100,150A,150B150C,160,1000,1000A, includes a chassis (20,106,152,162) having front and rear ends (20A,152A,20B,152B) and supported on right and left driven tracks (34,44,108,165). Right and left elongated flippers (50,60,102,154,164) are disposed on corresponding sides of the chassis and operable to pivot. A linkage (70,156,166) connects a payload deck assembly (D1,D2,D3,80,158,168,806), configured to support a removable functional payload, to the chassis. The linkage has a first end (70A) rotatably connected to the chassis at a first pivot (71), and a second end (70B) rotatably connected to the deck at a second pivot (73). Both of the first and second pivots include independently controllable pivot drivers (72,74) operable to rotatably position their corresponding pivots (71,73) to control both fore-aft position and pitch orientation of the payload deck (D1,D2,D3,80,158,168,806) with respect to the chassis (20,106,152,162).

Abstract: A vehicle incorporating a plurality of control motion gyroscopes (CMTs) contained within a support structure is described. Optionally, a mass shifting mechanism may also be incorporated in the vehicle. The vehicle and its CMTs are configured to have a plurality of gravitationally stable states on a sloped surface.

Abstract: A hybrid mobile robot includes a base link and a second link. The base link has a drive system and is adapted to function as a traction device and a turret. The second link is attached to the base link at a first joint. The second link has a drive system and is adapted to function as a traction device and to be deployed for manipulation. In another embodiment an invertible robot includes at least one base link and a second link. In another embodiment a mobile robot includes a chassis and a track drive pulley system including a tension and suspension mechanism. In another embodiment a mobile robot includes a wireless communication system.

Abstract: An endless track suspension is comprised of a suspension support beam having an idler wheel assembly connected to a respective one of opposed ends thereof. At least one of the idler wheel assemblies has an endless track binding mechanism. Support wheels are secured to the suspension support beam and project from a lower face thereof. A drive sprocket is secured elevated above the suspension support beam by a support arm. The drive sprocket is secured to a vehicle drive axle by a coupling ring. The drive sprocket, the support wheels and idler wheels constitute an endless track support assembly for supporting an endless track in drivable engagement thereabout. A flexible connection of the drive sprocket support arm and the support wheels absorbs shocks and vibrations transmitted to the vehicle drive axle by the displacement of the endless track over a rough ground surface.

Abstract: The invention relates to a method for propelling an articulated tracked vehicle (1) provided with at least a front and rear vehicle portion (2, 4), comprising a front drive shaft (6), which rotates a front track (8) on the front vehicle portion (2); a rear drive shaft (10), which rotates a rear track (12) on the rear vehicle portion (4), the front drive shaft (6) being disposed in the front vehicle portion (2) and the rear drive shaft (10) being disposed in the rear vehicle portion (4). At least one motor (20, 34, 36) rotates the respective front and rear drive shaft (6, 10) in order thus to propel the vehicle (1) at a speed in relation to a ground surface (16). The front drive shaft (6) is rotated at a first speed and the rear drive shaft (10) is rotated at a second speed, which first and second speeds are different, so that the front and rear tracks (8, 12) rotate at different speeds.

Abstract: An apparatus capable of omni-directional movement including a belt layer made of a plurality of interlocking flexible rings and a surface layer made of a laterally inelastic and longitudinally flexible material that surrounds the exterior of the belt layer. The device has a bladder located in the interior of the belt layer that provides structural support for the belt layer and surface layer and a hub that is in contact with the surface layer and is connected to an axle. Longitudinal motion occurs as the bladder, the belt layer, the surface layer, and the hub rotate together. Lateral motion occurs as the belt layer and the surface layer rotate around the bladder. Longitudinal motion is induced by a plurality of electromagnetic curvilinear motor drive rings that are located around the hub and are in contact with the surface layer.

Abstract: A retainer cap assembly for attaching a track assembly to a vehicle includes a housing and at least two latch plates disposed in the housing, pivotable about a common pivot axis, between a locked and an unlocked position. A lock bar is rotatably supported on the housing, wherein the lock bar rotates about an axis perpendicular to the pivot axis of the latch plates, so as to be selectively engaged with both of the latch plates to prevent the latch plates from rotating on the pivot axis when the latch plates are in a locked position and disengaged with both of the latch plates to allow the latch plates to rotate on the pivot axis when the latch plates are in an unlocked position.

Abstract: An all terrain vehicle and suspension providing frame members that pivot relative to each other and independent of supported track assemblies. Suspension frame sections pivot at supported bearings and torsion couplers. An endless track of each track assembly is trained around a framework having a drive sprocket and sets of idler wheels. The track assemblies independently pivot relative to the vehicle from a track suspension frame and supported sets of idler wheels mounted to torsion biased rocker arms that resist and bias the rocker arms and idler wheels to an equilibrium position and conformally shape the track to the terrain. Improved track drive lug surfaces are shaped to prevent track derailment. The vehicle frame and track assemblies independently rise, fall and pivot as obstacles of differing configurations and types are encountered to stabilize and maintain an operator body substantially parallel to the ground.

Abstract: A modular mobile robot with a chassis including a power source housed therein. Right and left hand track modules are each removeably coupled to the robot chassis. Each track module includes a side plate, at least one drive wheel rotatable with respect to the side plate, a motor for driving the drive wheel, at least one idler rotatable with respect to the side plate, and a track extending around the drive wheel, the side plate, and the idler. A turret assembly with its own turret drive subsystem is removeably coupled to the robot chassis via a quick release mechanism.

Abstract: A system for inserting a robot through an opening which includes a robot, the robot, payload, a tether, and a remote controller. The robot includes a first body supporting a first ground engaging drive and a second body supporting a second ground engaging drive. A pivoting connective linkage is provided between the first body and the second body. The connective linkage has an operative position in which the first body and the second body are in parallel spaced relation and an insertion position in which the first body and the second body are aligned on a common axis. An actuator is provided for moving the connective linkage from the insertion position to the operative position.

Abstract: A hybrid mobile robot includes a base link and a second link. The base link has a drive system and is adapted to function as a traction device and a turret. The second link is attached to the base link at a first joint. The second link has a drive system and is adapted to function as a traction device and to be deployed for manipulation. In another embodiment an invertible robot includes at least one base link and a second link. In another embodiment a mobile robot includes a chassis and a track drive pulley system including a tension and suspension mechanism. In another embodiment a mobile robot includes a wireless communication system.

Abstract: A climbing robot for travelling over adhesive surfaces with endless traction mechanisms (14) and, fastened to them at a distance, controllable adhesive feet (21) that circulate with the endless traction mechanisms (14) along guides (17) in the travel plane, by means of which the adhesive sides of their adhesive elements (15) always point towards the travel surface and wherein the adhesive elements (15) that support and move the climbing robot are switched “ON” and lowered onto the adhesive surface and all of the other adhesive elements (15) are switched “OFF” and raised from the adhesive surface, wherein the climbing robot has square running gear (11), one foot plate (13) each with a guide (17) running around the edges for a multitude of adhesive feet (21) driven by traction mechanisms is arranged in two diagonally opposite corner areas (18) of the running gear (11), wherein the foot plates (13) are attached to a support bar (12) of the running gear (11) and the adhesive feet (21) and therefore their adhesive

Abstract: A robotic system that can have a body and four flippers is described. Any or all of the flippers can be rotated. The flippers can have self-cleaning tracks. The tracks can be driven or passive. The robotic system can be controlled by, and send audio and/or video to and/or from, a remote operator control module. The methods of using and making the robotic system are also described.

Abstract: The vehicle (1) includes a chassis (2) and a pair of track assemblies (3, 4) mounted at the front and rear of the chassis respectively. At least one of the track assemblies is powered by a motor (5) to propel the vehicle. The chassis include mounting points (6, 7) for attaching the track assemblies. A deck area including rider footpads (8, 9) flanks a central motor mounting section (10).

Abstract: A suspension system for a lightweight robotic crawler is disclosed. The suspension system provides for mounting of a flexible endless track thereon. The suspension system includes a forward guide and a rearward guide around which the endless track can be looped. A deflector positioned between the forward guide and the rearward guide downwardly deflects a ground-engaging portion of the endless track to form a peaked area. The peaked area can support the lightweight robotic vehicle allowing alteration of a distribution of load over the ground-engaging portion of the endless track with respect to a supporting surface.

Abstract: A robotic system that can have a body and four flippers is described. Any or all of the flippers can be rotated. The flippers can have self-cleaning tracks. The tracks can be driven or passive. The robotic system can be controlled by, and send audio and/or video to and/or from, a remote operator control module. The methods of using and making the robotic system are also described.

Abstract: A robotic system that can have a body and four flippers is described. Any or all of the flippers can be rotated. The flippers can have self-cleaning tracks. The tracks can be driven or passive. The robotic system can be controlled by, and send audio and/or video to and/or from, a remote operator control module. The methods of using and making the robotic system are also described.

Abstract: A modular mobile robot with a chassis including a power source housed therein. Right and left hand track modules are each removeably coupled to the robot chassis. Each track module includes a side plate, at least one drive wheel rotatable with respect to the side plate, a motor for driving the drive wheel, at least one idler rotatable with respect to the side plate, and a track extending around the drive wheel, the side plate, and the idler. A turret assembly with its own turret drive subsystem is removeably coupled to the robot chassis via a quick release mechanism.

Abstract: A track type machine includes an integrated track adjustment/recoil system unit cantilever mounted in a track roller frame, and operable to resist movement of the idler along a recoil line. The integrated track adjustment/recoil system unit includes track adjust cylinder that is attached to a gas cylinder by a joining component that has two sets of identical external threads mated to the track adjust cylinder and the gas cylinder respectively. A track adjust piston is partially received in the track adjust cylinder, and a recoil piston is positioned in the gas cylinder. The recoil piston and the gas cylinder define a gas volume. The recoil piston, the gas cylinder, the joining component, the track adjust cylinder and the track adjust piston define a grease volume. Track tensioning is adjusted by adjusting the amount of grease in the grease volume, and the recoil action is adjusted by setting the gas pressure in the gas volume.

Abstract: A robotic system that can have a body and four flippers is described. Any or all of the flippers can be rotated. The flippers can have self-cleaning tracks. The tracks can be driven or passive. The robotic system can be controlled by, and send audio and/or video to and/or from, a remote operator control module. The methods of using and making the robotic system are also described.

Abstract: An all-terrain vehicle having a unique suspension system for enabling handicapped individuals or invalids to easily access the vehicle and be self-transportable over ground or an ice surface.

Abstract: Presented in is a self-contained jettison able tracked drive, which is intended for redundant propulsion of the multi-track vehicle. This drive enhanced survivability of military vehicle to perform under enemy fire and over anti-tank mines.

Abstract: A tracked vehicle (e.g., a tracked carrier vehicle) comprising a plurality of track assemblies for traction of the tracked vehicle. Each of the track assemblies supports a portion of a weight of the tracked vehicle when the tracked vehicle is in use. Each track assembly comprises: a first wheel and a second wheel spaced apart from one another along a longitudinal direction of the tracked vehicle; a number of support wheels arranged in an in-line configuration between the first wheel and the second wheel; and an endless track disposed around the first wheel, the second wheel, and the support wheels. The support wheels may comprise at least five (5) support wheels mounted such that, when the tracked vehicle is in use, the portion of the weight of the tracked vehicle supported by the track assembly is never applied to only one of the support wheels.

Abstract: A robotic system that can have a body and four flippers is described. Any or all of the flippers can be rotated. The flippers can have self-cleaning tracks. The tracks can be driven or passive. The robotic system can be controlled by, and send audio and/or video to and/or from, a remote operator control module. The methods of using and making the robotic system are also described.

Abstract: A suspension system for a machine is disclosed. The suspension system may have a front torsion axle assembly with a first arm connected at a first end to a first shaft, and a first axle connected to a second end of the first arm. The suspension system may also have a rear torsion axle assembly with a second arm connected at a first end to a second shaft, and a second axle connected to a second end of the second arm. The suspension system may further have a frame connected to an end of the first shaft and an end of the second shaft. The second ends of the first and second arms are oriented within common angular quadrants defined by a coordinate system having an axis passing through the first ends of the first and second arms and aligned with a travel direction of the machine.

Abstract: An all terrain vehicle and suspension providing frame members that pivot relative to each other and independent of supported track assemblies. Suspension frame sections pivot at supported bearings and torsion couplers. An endless track of each track assembly is trained around a framework having a drive sprocket and sets of idler wheels. The track assemblies independently pivot relative to the vehicle from a track suspension frame and supported sets of idler wheels mounted to torsion biased rocker arms that resist and bias the rocker arms and idler wheels to an equilibrium position and conformally shape the track to the terrain. Improved track drive lug surfaces are shaped to prevent track derailment. The vehicle frame and track assemblies independently rise, fall and pivot as obstacles of differing configurations and types are encountered to stabilize and maintain an operator body substantially parallel to the ground.

Abstract: In a first aspect, the invention is directed to an undercarriage for a tracked vehicle. The undercarriage includes a main frame including a frame body and an equalizer bar extending laterally on either side of a pivot connection with the frame body, a first track frame and a second track frame. A first front spherical bearing connects a first end of the equalizer bar and the front end of the first track frame. A second front spherical bearing connects a second end of the equalizer bar and the front end of the second track frame. A first rear spherical bearing connects the rear end of the main frame to the rear end of the first track frame. A second rear spherical bearing connects the rear end of the main frame to the rear end of the second track frame.

Abstract: In a first aspect, the invention is directed to an undercarriage for a tracked vehicle. The undercarriage includes a main frame including a frame body and an equalizer bar extending laterally on either side of a pivot connection with the frame body, a first track frame and a second track frame. A first front spherical bearing connects a first end of the equalizer bar and the front end of the first track frame. A second front spherical bearing connects a second end of the equalizer bar and the front end of the second track frame. A first rear spherical bearing connects the rear end of the main frame to the rear end of the first track frame. A second rear spherical bearing connects the rear end of the main frame to the rear end of the second track frame.

Abstract: An exhaust system is provided for a snowmobile having a front portion in which an engine is mounted, a rearward portion, and a track belt for propelling the snowmobile. The track belt is in a track belt tunnel that extends from behind the engine to a rear portion of the snowmobile. The exhaust system includes an exhaust pipe that extends from an exhaust outlet of the engine to the track belt tunnel. At least one exhaust outlet is located within the track belt tunnel at a position within the inner circumference of the track belt.

Abstract: This invention relates to a traction assembly for a vehicle which uses an endless traction band and a plurality of wheels for propulsion. More particularly, the traction assembly comprises a sprocket wheel which has a different size and number of sprocket teeth depending on whether the traction kit replaces the front wheels or the rear wheels of the vehicle. The sprocket wheel of the traction kit can also be configured such that its sprocket teeth are laterally offset. The traction kit can also comprise an anti-torque system that prevent physical contact between the traction kit and the vehicle and that can bias the position of the traction kit in order to improve the steering performance. Finally, the traction assembly can comprise a pivotable extension which lengthens the traction assembly and improves its traction capabilities.

Abstract: A track belt for a snow vehicle includes a belt body, a first lug, outer end circumferential regions, and contacting portions. The first lug is disposed at a central portion in a right/left direction of the belt body. The outer end circumferential regions are provided at both end portions in the right and left directions of the belt body, and include second lugs each having a height from the outer circumferential surface being no more than a half of a height of the first lug, or do not include lugs protruded from the outer circumferential surface of the belt body. The contacting portions are provided at the inner circumferential surface such that positions of the contacting portions in the right/left direction overlap with the outer end circumferential regions and are arranged to contact a rotating wheel member that opposes a snow surface across the belt body.

Abstract: A robotic system that can have a body and four flippers is described. Any or all of the flippers can be rotated. The flippers can have self-cleaning tracks. The tracks can be driven or passive. The robotic system can be controlled by, and send audio and/or video to and/or from, a remote operator control module. The methods of using and making the robotic system are also described.

Abstract: A robotic system that can have a body and four flippers is described. Any or all of the flippers can be rotated. The flippers can have self-cleaning tracks. The tracks can be driven or passive. The robotic system can be controlled by, and send audio and/or video to and/or from, a remote operator control module. The methods of using and making the robotic system are also described.

Abstract: A crawler traveling apparatus includes a traveling vehicle body having a rear axle case, a track frame supported via a pivot shaft to the rear axle case, a pair of front and rear driven wheels mounted at front and rear end portions of the track frame, a pair of the rear driven wheels being provided on the right and left sides across a rear end portion of the track frame, a free wheel mounted at an intermediate portion of the track frame, a crawler entrained about a drive wheel, the front and rear driven wheels and the free wheel, a rearwardly downward inclined face formed at an upper portion of the rear end portion of the track frame, the inclined face being configured to cause an amount of earth/sand to drop off its surface; and a rear upper cover provided at an upper portion of the rear portion of the track frame in the vicinity of said inclined face, the rear upper cover forming a rear upper inclined face that is oriented downward in the right/left outward direction, the rear upper inclined face being conf

Abstract: A snowmobile is disclosed having improved drive train including a continuously variable transmission (CVT) having a drive belt looped around a driving pulley and a driven pulley, and a transversely arranged jackshaft wherein the driven pulley is connected directly onto the outer surface of one end of the jackshaft. The transverse jackshaft is preferably made from a thin-walled hollow tube and the driven pulley is preferably press fitted thereon. A method of assembling a snowmobile drive train is also disclosed.

Abstract: A gasoline engine powered snowboard having an endless track trained about a support frame containing driven and idler wheels. Engine operation is directed from an upright operator support column. A molded chassis is hinge coupled to pivot about alternative contoured track support pan assemblies. The pan support assemblies cooperate with flexible track surfaces (e.g. fringe or pleat members) and foot supports to enable steering with foot and body movements. A lower support pan exhibits convex edge surfaces that contact track pleats or fringe pieces and includes an elliptic longitudinal channel. Alternative upper support pans provide a reciprocating wheeled steering plate, longitudinal drive lug channels and contoured snow diversion surfaces and/or an agitator. Internal track surfaces include UHMW pieces at or aligned to the drive lugs. Ground contact lugs exhibit traction promoting and snow clearing contoured profiles, shapes and recesses.

Abstract: A method of operating a production line comprises the steps of supporting equipment in the production line on a plurality of crawlers comprising at least one rolling track and a structural support for supporting the equipment. A first plurality of lifting magnets coupled to an interior surface of said at least one rolling track is configured to oppose a second plurality of lifting magnets coupled to an exterior surface of said structure support to lift the structural support, such that the structural support floats between and within said at least one rolling track. The magnetic fields experienced by the first and second plurality of lift magnets are adjusted to translate the at least one rolling track, such that the crawlers move along the production line.

Abstract: The invention relates to the automotive technique. The use of the present invention for increasing the cross-country ability all-terrain vehicle allows for obtaining technical result in the form of simplifying the all-terrain vehicle structure and increasing the reliability. For this purpose, the all-terrain vehicle comprises: an engine transmission section; at least one pair of supporting wheels mounted in the bottom part of the engine-transmission section at each of side faces thereof; driving wheels for number of the supporting wheels, the driving wheels being mounted on one side of each of the supporting wheels; a pair of caterpillar drives each one encircling the respective of the supporting wheels along with the driving wheel mounted on one side from the supporting wheel; a driver configured for transmitting a torsion torque from the engine-transmission section to the driving wheels.

Abstract: The mobile robot includes a chassis, a pair of drive system, a manipulator arm with a turret. The pair of drive systems is operably connected to opposed sides of the chassis. The turret is rotationally attached to the platform. The first link of the manipulator arm is attached to the turret at a first joint. The manipulator arm has at least a first link, and the first link is adapted to function as a traction device.

Abstract: A device for facilitating the movement of a vehicle across ground comprises a track able to move around a board. The device includes a track for contacting ground that is mounted on a board. Brackets are provided for attaching the board to a vehicle. The track is movable in a direction independent of the direction of movement of the vehicle in at least the reverse direction relative to the vehicle's direction of movement. That track is able to move around the board by means of cylinders arranged in the form of a belt extending around the board between the board and the track. The device can be used to facilitate movement of off-road vehicles across obstacles. It can also be used to provide snow-free sledges and skis. It is also envisaged that the device may be incorporated into a trolley, which can be used on uneven surfaces.