Abstract: An apparatus for handling objects such as information technology equipment racks in an environment such as a data center. In one aspect, the apparatus includes a body having a first mount on a first interior side of the body; and second mount on a second interior side of the body and in same horizontal position as the first mount; and a lifting system comprising one or more lifting elements with one or more retractable wheels coupled each of the one or more lifting elements, wherein, when the lifting system extends outside of the body to handle an object, the object rests on the one or more retractable wheels that are in an extended position, and when the lifting system is substantially inside the body, the retractable wheels are in a retracted position, and the object rests on the first mount and the second mount of the body.

Abstract: A semiconductor processing system includes a first semiconductor processing site and a second semiconductor processing site. The system includes an unmanned electric vehicle configured to carry a portable cleanroom stocker between the first and second semiconductor processing sites. The portable cleanroom stocker is configured to maintain cleanroom conditions within the portable cleanroom stocker during transportation.

Abstract: A robotic item retrieval and transport apparatus includes at least one item retrieval mechanism that is minimally exposed while stored and/or engaged in loading or unloading of objects relative to a deck (e.g., upper surface) thereof. Actuators and at least major portions of one or more movable implements are arranged below the deck. Loading and/or unloading of objects may include lateral sliding, such as by pulling the object while it is supported by an extrinsic support surface. At least substantial portions of an item retrieval mechanism may remain outside a central target area of a deck, to provide a unobstructed or minimally obstructed deck surface for holding objects. The apparatus may be used with at least one movable pallet element. A pallet element and/or a retrievable item may include one or more features detectable by a sensor.

Abstract: The invention relates to a modular sliding fork for a fork-lift truck or pallet truck, a fork-lift truck or pallet truck provided therewith and a method therefor. The modular sliding fork includes a sliding part configured to be adjusted in length direction relative to a fork part of a fork of a fork-lift truck or pallet truck, a drive system for sliding the modular sliding fork relative to the fork part for the purpose of extending and/or shortening the fork; and a locking mechanism for locking the modular sliding fork relative to the fork part at a desired position. The drive system utilizes a movement of the fork-lift truck or pallet truck for the purpose of sliding the modular sliding fork.

Abstract: A machine for handling heavy components in a heavy equipment environment. In an example implementation, the machine includes a truck having at least two front wheels and at least one rear wheel. A outrigger portion extends forward from the truck. The front wheels are attached at a forward end of the outrigger portion. A mast extends vertically from a track extending forward from the truck on a base of the outrigger portion. The mast is movably extendable or retractable along the track. A carriage is mounted on the mast and configured to move vertically on the mast. A pair of forks are mounted on the carriage to move vertically when the carriage is controlled to move. A personnel platform is mounted on the carriage independent of the mounting of the forks on the carriage. A remote control panel is configured to override a cab control panel under operator control. The remote control panel includes a plurality of controls for moving the carriage and for extending or retracting the mast.

Abstract: The powered hand truck and dolly system for ISO (International Organization for Standardization) containers is a system for moving ISO containers. The system includes at least one dolly and a powered hand truck. The hand truck includes two booms that are vertical for storage and rotate into a horizontal position for engaging the container. The ends of the booms have shafts with cams for engaging standard twist lock connector receptacles on one end of the container. Each dolly also has a shaft with a cam for engaging a standard twist lock connector receptacle on the other end of the container. The dollies include bars that are vertical for storage and rotate into a horizontal position for connecting the dollies to one another such that their shafts are appropriately positioned to align with their associated connector.

Abstract: Distance measurements are performed by a fork pocket detection sensor at a position at which the fork pocket detection sensor faces one of fork pockets and at a position at which the fork pocket detection sensor faces the central position in the horizontal direction between the fork pockets on a pallet side face, and information obtained by combining pieces of distance-measurement information acquired by the distance measurements is compared with information of predefined shapes of the fork pockets, so as to specify the positions of the fork pockets. Hereby, it is possible to accurately detect the positions of the fork pockets without causing a decrease of conveyance efficiency.

Abstract: A pantograph assembly may include a mast carriage assembly comprising a trunnion cross-member and a trunnion shaft coupled to the trunnion cross-member, and a pantograph mechanism coupled to the trunnion shaft.

Abstract: A method and apparatus of moving a picker on an automatically guided vehicle (AGV) along with a plurality of totes to a successive plurality of inventory stock bins to allow the picker to successively retrieve each of a plurality of stock items from the stock bins and place the respective items in a preselected one of the plurality of totes based on a customer order. In some embodiments, the picker is a human picker. In some embodiments, the totes are shipping containers.

Abstract: A pallet wedge for slidingly displacing a loaded pallet located on top of the pallet holder through ground engagement of ground runners on the pallet wedge as the pallet holder moves forward until the loaded pallet slides off the pallet wedge.

Abstract: A component moving system may include a cart, and a component support assembly coupled to the cart. The component support assembly may include a component cradle moveable in first linear translational directions, second linear translational directions that are orthogonal to the first linear translational directions, third linear translation directions that are orthogonal to the first and second linear translational directions, and first rotational directions.

Abstract: A hydraulic training system includes a cart, with a fluid reservoir, a motor, a first pump and a second pump situated on the cart. The first and second pumps are in fluid communication with the fluid reservoir and are operatively connected to be driven by the motor. A drivable wheel is rotatably attached to the cart and is selectively connectable to the first pump to drive the wheel. A steering system is selectively connectable to the second pump and arranged to steer a steerable wheel extending from the top of a first planar surface.

Abstract: An apparatus for controlling a load handling device of an industrial vehicle includes a lifted height detector that detects a lifted height of the load handling device, a tilt angle detector that detects a tilt angle of the load handling device, a loading pump that pumps hydraulic oil from a hydraulic tank in the industrial vehicle and supplies the hydraulic oil to a lift cylinder and a tilt cylinder, a drive that drives the loading pump, and a controller that controls the flow rate of hydraulic oil supplied to the lift cylinder and the tilt cylinder. When the forward tilt angle of the load handling device is greater than a first regulation tilt angle and a lifted height of the load handling device is higher than a predetermined reference height, the controller regulates the flow rate of hydraulic oil supplied to the lift cylinder.

Abstract: A carriage frame includes first and second side members supporting a floating fork pin, where the floating fork pin is movably mounted in respective fork pin slots in the first and second side members and is adapted to receive load carrying forks. The first and second side members each includes a locking aperture positioned spaced from the fork pin slots. A pair of lock plates are secured to ends of the floating fork pin, respectively, where each of the lock plates includes a lock pin slot and a lock pin hole positioned in substantial alignment with the locking apertures in the first and second side members. A pair of fork pin locks extend through the locking apertures of the first and second side members and are selectively extended through one of the lock pin slot and the lock pin hole.

Abstract: A duckbill pod (100) having an ejector mechanism, the duckbill pod (100) comprising a tray (10) for providing a transport surface for goods or material, a pusher plate (50) arranged substantially perpendicular to the tray (10), a drive arrangement for actuating the pusher plate (50) and reciprocate same between a mouth and a rear end of the duckbill pod (100), and a lifting plate (20) secured to the tray (10) for attaching the duckbill pod (100) to a loader.

Abstract: An industrial truck is shown with a lifting frame, on which a load-receiving section is arranged so as to be movable vertically. The load-receiving section has at least one degree of movement freedom with respect to the lifting frame, which lies in a plane perpendicular to the main direction of travel of the industrial truck and has at least one horizontal component. In addition, a vibration control system is provided for damping or preventing vibrations in the relative position of load-receiving section and lifting frame.

Abstract: A vehicle trailer including a trailer chassis with two opposed sides secured together at/adjacent one end by a crossmember, to form a U-shaped structure with an interior space between the arms of said U; a load-bearing tailgate between the sides of said chassis to removably close off said interior space; a loading device mounted in said interior space adjacent said crossmember and including a loading fork which can be moved up and down and which provides at least one load-engaging member; the or each said load-engaging member having a length such that the end of said load-engaging member furthest from said crossmember can be positioned to engage said load-bearing tailgate so as to stabilise said load-engaging member and to transfer load from said load-engaging member to said tailgate.

Abstract: A materials handling vehicle is provided comprising: a support structure including a fixed member; a movable assembly coupled to the support structure; a hydraulic system; and a control system. The support structure further comprises lift apparatus to effect movement of the movable assembly relative to the support structure fixed member. The lift apparatus includes at least one ram/cylinder assembly. The hydraulic system includes a motor, a pump coupled to the motor to supply a pressurized fluid to the at least one ram/cylinder assembly, and at least one electronically controlled valve associated with the at least one ram/cylinder assembly. The control structure may estimate a speed of the movable assembly from a speed of the motor and control the operation of the at least one valve using the estimated movable assembly speed.

Abstract: A materials handling vehicle is provided including: a support structure including a fixed member; a movable assembly coupled to the support structure; a hydraulic system; and a control system. The support structure further includes lift apparatus to effect movement of the movable assembly relative to the support structure fixed member. The lift apparatus includes at least one ram/cylinder assembly. The hydraulic system includes a motor, a pump coupled to the motor to supply a pressurized fluid to the at least one ram/cylinder assembly, and at least one electronically controlled valve associated with the at least one ram/cylinder assembly. The control structure may estimate a speed of the movable assembly from a speed of the motor and calculate an updated pump volumetric efficiency using the estimated movable assembly speed and a determined movable assembly speed.

Abstract: A pallet fork including a frame and a fork tine. The frame supports a fork bar and a carriage plate. Further, the fork bar and the carriage plate extend in a longitudinal direction of the pallet fork. The fork tine is mounted to the fork bar. Also, the fork tine has a swingable motion and a lateral motion relative to the fork bar. Moreover, the fork tine includes a vertical leg and a horizontal leg. A bracket is attached to the vertical leg of the fork tine. A first locking member is selectively inserted in the bracket to engage the fork tine with the carriage plate and restrict the swingable motion of the fork tine.

Abstract: A powered pallet truck is provided having a frame assembly that includes a base support portion and a load lift portion. The powered pallet truck has a lift cylinder device connected to the load lift portion and to the base support portion.

Abstract: A materials handling vehicle includes a power unit, a mast assembly coupled to the power unit, and a reach assembly coupled for vertical movement on the mast assembly. The mast assembly includes first, second, and third weldments, wherein the first weldment is fixed to the power unit, the second weldment is movable with respect to the first weldment, and the third weldment is movable with respect to the first and second weldments. The reach assembly includes an extension/retraction mechanism for effecting horizontal movement of the reach assembly relative to the mast assembly. Components of the vehicle have been redesigned and/or rearranged to improve operator visibility.

Abstract: A materials handling vehicle includes a power unit, a mast assembly coupled to the power unit, and a reach assembly coupled for vertical movement on the mast assembly. The mast assembly includes first, second, and third weldments, wherein the first weldment is fixed to the power unit, the second weldment is movable with respect to the first weldment, and the third weldment is movable with respect to the first and second weldments. The reach assembly includes an extension/retraction mechanism for effecting horizontal movement of the reach assembly relative to the mast assembly. Components of the vehicle have been redesigned and/or rearranged to improve operator visibility.

Abstract: A materials handling vehicle includes a power unit, a mast assembly coupled to the power unit, and a reach assembly coupled for vertical movement on the mast assembly. The mast assembly includes first, second, and third weldments, wherein the first weldment is fixed to the power unit, the second weldment is movable with respect to the first weldment, and the third weldment is movable with respect to the first and second weldments. The reach assembly includes an extension/retraction mechanism for effecting horizontal movement of the reach assembly relative to the mast assembly. Components of the vehicle have been redesigned and/or rearranged to improve operator visibility.

Abstract: A cart-handler for mobile carts within narrow confines is provided. The cart-handler is constructed from an elongate frame having at least one upright support rail and opposite ends supported on wheels. A pair of stabilizers is connected to the frame with each stabilizer being movable into a retracted position on the frame and into a laterally-extended position in which the stabilizer directly engages an underlying floor surface to aid in supporting the cart-handler on the floor. When the stabilizers are placed in the laterally-extended position, each stabilizer extends outward from a common side of the elongate frame. A cart-lifter is mounted on the support rail of the frame and is movable vertically along the support rail so that the cart-lifter can engage, elevate, and support a separate mobile cart above the underlying floor surface. The cart-handler can be interconnected to a pair of elevated mobile work platforms.

Abstract: A railway car door operator assembly is adapted for use in opening or closing railway car doors. The assembly is mountable on a self-propelled vehicle and includes a base mountable on the vehicle. An elongated arm having one end secured to an articulated joint on the base secures the arm to the base limiting movement of the arm to movement in a substantially horizontal plane. Another end of the arm is secured to a releasable restraint for releasable connection to a railway car door.

Abstract: A powered pallet truck is provided having a drive motor mounted in a drive wheel, a lift mechanism in general fore-and-aft alignment with the center of the drive wheel, and a pressurized fluid supply mechanism mounted to the load lift portion of the frame assembly. In one aspect, the powered pallet truck has a fluid conduit connected to an upper portion of a lift cylinder device adjacent a pivot connection between the lift cylinder device and a load lift portion of the pallet truck to limit movement of the fluid conduit during up and down movement of the load lift portion. In another aspect, the powered pallet truck has a base support portion with an arcuate window permitting movement of one or more cables extending therethrough as a steering assembly of the pallet truck is turned.

Abstract: A workpiece container storage and handling system includes a base, a number of wheels connected to the base, and a container handling system connected to the base. The wheels provide for movement of the base. The container handling system is defined to hold at least two containers in a vertically overlying orientation relative to each other. The container handling system is defined to provide for controlled vertical travel of the at least two containers in unison relative to the base. Also, the container handling system is defined to provide for controlled and independent horizontal travel of each of the at least two containers relative to the base.

Abstract: A cart-handler for mobile carts within narrow confines is provided. The cart-handler is constructed from an elongate frame having at least one upright support rail and opposite ends supported on wheels. A pair of stabilizers is connected to the frame with each stabilizer being movable into a retracted position on the frame and into a laterally-extended position in which the stabilizer directly engages an underlying floor surface to aid in supporting the cart-handler on the floor. When the stabilizers are placed in the laterally-extended position, each stabilizer extends outward from a common side of the elongate frame. A cart-lifter is mounted on the support rail of the frame and is movable vertically along the support rail so that the cart-lifter can engage, elevate, and support a separate mobile cart above the underlying floor surface. The cart-handler can be interconnected to a pair of elevated mobile work platforms.

Abstract: It is intended to provide a transferring apparatus for a heavy object cassette as well as a transferring method for the heavy object cassette, which is mainly operable mechanically without using hydraulic pressure, by which it is easy to load the heavy object cassette and an operation speed is improved. The transferring apparatus is provided with a heavy object cassette which is a heavy object contained in a cassette integrally, a common steel plate 15 to which support rods 6a, 6c are fixed, the support rods being inserted in holes 4a formed horizontally in the heavy object cassette 4, and a play mechanism 51 which allows adjustment of a relative position between the holes 4a and the support rods 6a, 6c by adjusting a position of the common steel plate 15, a base unit 7 having thereon the play mechanism 51 and a lifting and lowering device 5, and a slide mechanism 72 which supports the base unit 7 movable forward and backward relative to a main body 71 of the transferring apparatus.

Abstract: A materials handling vehicle is provided comprising: a power unit; a work assembly coupled to the power unit comprising a first auxiliary device; and a fluid supply system. The fluid supply system may comprise: pump structure for supplying a fluid; a first manifold apparatus located on the power unit; a second manifold apparatus located on the work assembly; and fluid supply line structure coupled between the first and second manifolds. The first manifold may receive fluid from the pump structure and comprise valve structure for maintaining fluid pressure at an output port of the first manifold apparatus at a commanded pressure substantially equal to or greater than an operating pressure of the first auxiliary device.

Abstract: An arm of a forklift fork including a substantially horizontal arm having a supporting surface for supporting and carrying a load. The arm may include a carriage that also includes a supporting surface for supporting and carrying a load, wherein the carriage is arranged to move in parallel to the arm in relation to the supporting surface of the arm. The carriage may include a caterpillar track for moving. The arm may include two adjacent arm parts fastened to each other, between which parts the carriage is located. The arm may include several separate units, each containing members which make the load capable of rolling in parallel to the arm. Each unit is also arranged to remain in its place.

Abstract: The invention relates to an industrial truck (10; 15) comprising a truck body (20) and a load supporting member (30). The load supporting member (30) is movable in a vertical direction (40) and in a horizontal direction (50; 80) in relation to the truck body (20). According to the invention, the industrial truck (10; 15) is adapted to reduce the maximum allowed acceleration of the load supporting member (30) in the vertical direction (40) when the load supporting member is located at specific horizontal positions in relation to the truck body (20). The invention also pertains to a corresponding method and a computer program.

Abstract: A lift that is configured to securely lift, carry and deposit a control unit using three degrees of movement. The lift comprises a chassis having a support frame and a power source connected to the support frame. A pivot member rotatably connects to the support frame, wherein the pivot member has a pivot plate and a rod rotatably connected to the pivot plate. A lift frame connects to the rod of the pivot plate, wherein a lift arm rotatably connects to the lift frame. The lift further comprises a pressurized fluid drive operatively connected to the power source and operatively connected to the pivot plate, the lift frame and the lift arm. The fluid drive is configured to reciprocally move the pivot plate, the lift frame and the lift arm such that the lift arm moves in three degrees of movement with respect to the chassis.

Abstract: This invention relates to a forklift truck (1) of the type suitable for mounting on the rear of a carrying vehicle, the forklift truck comprising a u-shaped chassis (3) having a vertical mast (17) mounted thereon. The vertical mast carries a side shift mechanism (21), the side shift mechanism comprising a fixed carriage (23) with a movable carriage (25) slidably mounted thereon. A pair of fluid actuated rams (27, 29) is provided to slide the movable carriage (25) laterally relative to the fixed carriage (23). A rotating cylinder (49) is provided to rotate a pair of forks (19) mounted on the movable carriage. The configuration achieves greater side shift without the use of rollers or chains and permits the use of a rotating cylinder.

Abstract: The pallet jack apparatus provides lateral fork adjustment between the two forks, each having a forwardly disposed pivoted wheel for added fork support. The lateral fork adjustment is controlled by the horizontal control lever on the stem. The lateral fork adjustment is via a motor with pinion gear which directly drives the first and second fork gears. The apparatus further provides height adjustment for the forks via the vertical control lever on the stem. The control levers are positioned within the handle interior of the oblong circular handle which guards against inadvertent control movements while providing superior leverage for positioning the apparatus.

Abstract: An apparatus is for displacing objects which can be picked up. The apparatus includes a fork-like member provided with teeth for picking up the objects, a transporting device connected to this member, a device for moving the fork-like member vertically, and a control device for controlling the transporting and moving devices. The apparatus includes at least one pair of mutually adjacent teeth of the fork-like member which is equipped with one flexible carrier arranged on each tooth and drivable in longitudinal direction of the tooth. When the objects are set down, this carrier can impart a determined speed to the objects such that the distance between two rows of set-down objects standing perpendicularly of the direction of the teeth can be regulated in a flexible manner by way of adjusting the speed of the carrier.

Abstract: A pallet jack with a pallet engaging fork having separate and independently movable first and second fork arms connected to independently controlled and operable first and second fork arm elevating means, for lifting a pallet loaded with a stack of items so that when the stack of items leans and is out of balance one fork arm can be elevated higher than the other to compensate and restore balance to the stack of items.

Abstract: A warehousing system for palletized cargo, and an automated loading/unloading system for use with the same. The warehousing system includes a feed conveyer and a plurality of storage racks. A traveling conveyor carries the cargo from the feed conveyor to the individual racks, and from the racks to a loading/unloading conveyor which carries the cargo to the loading/unloading docks. The traveling conveyor rides on a wheeled chassis that is guided between the receiving and discharge locations on tracks. The storage racks are stackable in tiers, and the traveling conveyor has a deck that raises and lowers to be level therewith. The automated loading/unloading dock includes a rigid, extensible plate having an upper surface for supporting a load of palletized cargo, with a drive mechanism being mounted to the inner end of the plate to translate it in and out of the transport vehicle. The plate carries a load of palletized cargo into or out of the transport vehicle en masse.

Abstract: Disclosed herein is an automatic folding fork device for forklift trucks. The folding fork device is operated so that forks are rotated upwards and folded by the rotation of a hydraulic motor when a driver driving in a forklift truck easily manipulates a lever or switch, thus allowing the forklift truck to move safely, with the forks in a folded state. Further, this invention is constructed so that external threaded parts, having threads formed in opposite directions, are provided on both sides of the outer circumferential surface of a shaft, and coupling pipes having internal threaded parts corresponding to the external threaded parts are provided, thus allowing an interval between the forks mounted to the coupling pipes to be adjusted, according to the rotating direction of the hydraulic motor.

Abstract: A loader attachment including a frame having a left sidewall and a right sidewall. The loader attachment also includes a first track with a tine slidably coupled to the first track, a second track with a tine slidably coupled to the second track, a first actuator mounted on the right sidewall of the frame for initiating sliding of the first tine along the first track toward and away from the left sidewall, and a second actuator mounted on the left sidewall of the frame for initiating sliding of the second tine along the second track toward and away from the right sidewall of the frame.

Abstract: The hinge comprises a first link element and a second link element hinged to a free end of a telescopic arm of the lift truck. The first link element is commanded to oscillate about a hinge axis by first means for actuating acting between the free end and the first link element. The second link element, which supports a quick-release mechanism for a tool, is commanded to oscillate about the same hinge axis by second means for actuating acting between the first link element and the second link element.

Abstract: A fork lift truck attachment having side shiftable forks which can be adjusted for side loading and which can be tilted fore and aft laterally.

Abstract: A forklift for mounting on a carrier vehicle which has a two-part upright mast and a telescopic boom substantially orthogonal to the mast slidable up and down the mast to move a fork carrier on the boom in both a horizontal and a vertical direction. Retractable wheels may be provided to support forks on a loading bay floor or truck chassis.

Abstract: A lift truck attachment for handling loads comprises a main frame assembly for attachment to an elevator of a lift truck and a lower slide assembly. The lower slide assembly includes an elongated sliding element for performing a reciprocal motion relative to the main frame assembly. A bottom slide cross tube is furnished and has an elongated structure extending substantially perpendicular to the elongated sliding element. An elongated pusher plate is attached to the bottom slide cross tube and extends substantially parallel to the elongated sliding element. A first shear plate has a first hole and is attached to an end of the bottom side cross tube. A second shear plate has a second hole and is rotatably attached to the first shear plate with a rotation axis disposed substantially parallel to the elongated sliding element. The first hole and the second hole have the same distance from the rotation axis. A threaded safety bolt penetrates through the first hole and through the second hole.

Abstract: The hand truck/forklift as disclosed in this application is new and useful as an improvement of the conventional hand truck in that it enables lifting of loads up to four feet high as-well-as transporting loads commonly carried on a conventional hand truck. This lever operated lift is also an improvement in that it enables lifting of heavy loads by a person without the use of more expensive power operated lifts where space and environmental concerns make them impractical to operate. This lever operated lift enables the operator to lift heavy loads safely equaling the lifters body weight plus his lift strength while keeping his back in an up-right posture. The lever lift assembly is also new and useful in that it allows the operator to lift a load and allows that load to be held at a selected height by use of a sleeved punched post frame assembly with spring loaded set pins which are manually retracted by use of hand operated cable from the lever side of the lift.

Abstract: A lifting apparatus including a horizontal framework having a connector connected to a bridge crane trolley and a motor mounted on the horizontal framework, a telescoping mast unit coupled to one side of the horizontal framework and having upper, middle, and lower mast assembly and adjusting a height of the lifting apparatus, a fork tine assembly adjusting the tine center to center distance, and a counterbalance coupled to the other side of the horizontal framework is provided. The horizontal framework is coupled to an overhead bridge crane and is accessible to any load located within a minimum amount of aisle space.

Abstract: A towbar adapter assembly that attaches to a towbar boom and acts as a link between the towbar boom and a vehicle attachment point. The assembly has a base for attachment to the towbar boom and an anchoring strut that attaches to the vehicle. The base is incrementally positionable with respect to the towbar boom and the anchoring strut is incrementally positionable with respect to the base.

Abstract: A fork lift with retractably extendable loading prongs for lifting loads from either side of a vehicle. The fork lift includes a mechanism for displacing the prongs over and across the vehicle, which mechanism has front and rear transverse girders which can be rigidly secured to the vehicle's chassis. The mechanism further includes front and rear masts, sprocketed wheels mounted on the masts to move the front and rear masts reciprocally, and a longitudinal beam which is coupled to the masts. The longitudinal beam can move up and down. Front and rear uprights extend downwardly from the longitudinal beam. The prongs are retractably engaged to the bottom of the uprights and are moved with hydraulic pistons.

Abstract: A fork lift with retractably extendable loading prongs for lifting loads from either side of a vehicle. The fork lift includes a mechanism for displacing the prongs over and across the vehicle, which mechanism has front and rear transverse girders which can be rigidly secured to the vehicle's chassis. The mechanism further includes front and rear masts, sprocketed wheels mounted on the masts to move the front and rear masts reciprocally, and a longitudinal beam which is coupled to the masts. The longitudinal beam can move up and down. Front and rear uprights extend downwardly from the longitudinal beam. The prongs are retractably engaged to the bottom of the uprights and are moved with hydraulic pistons.