Abstract: A counterweight for a hydraulic shovel, which is applicable to a compact to large-sized hydraulic shovels, and is capable of realizing favorable engine maintainability and assurance of sufficient mass, is provided. For this purpose, supporting column portions (12b, 12c) are vertically provided at left and right of a counterweight (12). The left and right supporting column portions are constituted as an increase amount of mass of the counterweight. At least one of a floor frame (30), a canopy (40), outer casings (14, 16) and engine partition walls (33a, 33b) is supported at the left and right supporting column portions. Further, an engine (13) is placed at a position fronting to between the left and right supporting column portions.

Abstract: A vehicle ballast system for improving the balance of a vehicle. The system is particularly well suited for use in the bed of a pickup truck but is not limited to that deployment. The system includes one or more ballast units. Each ballast unit includes a frame set and a ballast element. The frame set retains the ballast element therein. The ballast element may be one or more concrete blocks. The frame set includes an upper frame and a lower frame. The respective frames are connected together in a manner to contain the ballast element using a front retaining rod and a rear retaining rod is preferably affixable to a bracket secured to the rear of the vehicle. A tether may be removably connected between the upper frame and a securing point of the vehicle. A shock-absorbing lanyard may be employed at the rear of the system as a restraint upon sudden deceleration of the vehicle.

Abstract: A structure of mounting a weight in a forklift truck which has a frame and the weight that is to be connected and fixed to the frame by a bolt and a nut includes a first hole, a second hole, a first fitting part and a second fitting part. The first hole is formed through the frame. The second hole is formed through the weight in such a manner that the first hole and the second hole correspond to each other. The first fitting part is formed on the frame. The second fitting part is formed on the weight in such a manner that the first fitting part and the second fitting part fit to each other and that the first hole and the second hole are aligned with each other when the frame and the weight are combined together.

Abstract: A vehicle bed liner apparatus includes a peripherally sealed flexible top wall and flexible bottom wall for containing a quantity of ballast liquid, e.g. water. Compartment boundary means are located at plural internal non-peripheral regions between the flexible top wall and the flexible bottom wall. The compartment boundary means are in contact with the flexible top wall and the flexible bottom wall. The compartment boundary means define internal compartment boundaries. The plural non-peripheral compartment boundaries and plural internal non-peripheral regions between the flexible top wall and the flexible bottom wall that are not in contact with the compartment boundaries define plural ballast compartments internal to the wall means. The ballast compartments are in communication with each other. A combination fill and drain valve in the flexible top wall is provided for filling the ballast compartments with a water and for emptying the water from the ballast compartments.

Abstract: A ballast assembly for vehicles is mounted on one vehicle portion to balance the vehicle and counterbalance the weight of an implement such as a snowplow assembly on another portion of the vehicle. The ballast assembly includes a ballast member having a predetermined weight and a contour coordinated to the vehicle shape. A vehicle mounting member removably mounts the ballast member to the vehicle such as at a hitch receiver socket or to the vehicle frame at the rear end of the vehicle. The ballast member may comprise one or more metal plates stacked and secured to one another, or a hollow enclosure either temporarily or permanently filled with a weighted material such as sand, gravel, or concrete.

Abstract: An industrial truck, in particular a fork lift truck, is provided with a rear weight and an internal combustion engine. The internal combustion engine is fastened to the rear weight. The internal combustion engine is advantageously mounted so that it can oscillate around an axis that extends in the transverse direction of the industrial truck.

Abstract: An industrial vehicle includes a vehicle body, a pair of rear wheels, a rear axle for supporting the rear wheels, a lock cylinder, a counterweight and a coupling portion. The rear axle is supported to be pivotable relative to the vehicle body. The lock cylinder is located between the vehicle body and the rear axle. The lock cylinder limits pivoting of the rear axle. The counterweight forms a rear portion of the vehicle body. The counter weight supports the rear axle. The coupling portion is integrally formed with the counterweight to couple the fluid pressure cylinder with the vehicle body. This reduces the number of components and the manufacturing steps of the industrial vehicle.

Abstract: The present invention relates to a stabilizing weight assembly for a vehicle, such as a tractor. The stabilizing weight assembly, in one embodiment, includes a weight holder rotatably connected to a weight holder wheel. The weight holder wheel can make contact with the driving surface, depending upon the driving conditions. The stabilizing weight assembly enhances the traction, safety and performance of vehicles such as tractors.

Abstract: A ballast system for use in a cargo bed of a vehicle, such as a pick-up truck, provides generally even weight distribution over rear or powered wheels of the vehicle. The ballast system provides additional weight to the cargo bed of the vehicle, thereby improving stability, handling, and rear wheel traction, especially during inclement weather, such as in snow or rain. The ballast system may be rolled-up into a compact roll during non-use for convenient storage. The ballast system has a plurality of weighted cross-members laminated, attached, or bonded between two generally pliable mats. The cross-members are, preferably, equally spaced apart from each other along widths of the mats and transverse to a longitudinal direction of the cargo bed of the vehicle. The ballast system is readily rolled-up into a compact roll for convenient storage.

Abstract: An axle supporting structure for supporting an axle beam for an industrial vehicle includes a center pin, a pair of axle supporting units and a counterweight. The center pin protrudes from the axle beam. Each axle supporting unit has formed therethrough an insertion hole in which the center pin is inserted. The axle supporting unit has an upper axle supporting member and a lower axle supporting member which is detachably connected to the upper axle supporting member. The pair of axle supporting units is spaced from each other in a traveling direction of the vehicle. The center pin is rotatably supported between the pair of axle supporting units. The upper axle supporting members of the axle supporting units are cast in the counterweight.

Abstract: An industrial vehicle includes a vehicle body, a pair of rear wheels, a rear axle for supporting the rear wheels, a lock cylinder, a counterweight and a coupling portion. The rear axle is supported to be pivotable relative to the vehicle body. The lock cylinder is located between the vehicle body and the rear axle. The lock cylinder limits pivoting of the rear axle. The counterweight forms a rear portion of the vehicle body. The counter weight supports the rear axle. The coupling portion is integrally formed with the counterweight to couple the fluid pressure cylinder with the vehicle body. This reduces the number of components and the manufacturing steps of the industrial vehicle.

Abstract: A ballast assembly for vehicles is mounted on one vehicle portion to balance the vehicle and counterbalance the weight of an implement such as a snowplow assembly on another portion of the vehicle. The ballast assembly includes a ballast member having a predetermined weight and a contour coordinated to the vehicle shape. A vehicle mounting member removably mounts the ballast member to the vehicle such as at a hitch receiver socket or to the vehicle frame at the rear end of the vehicle. The ballast member may comprise one or more metal plates stacked and secured to one another, or a hollow enclosure either temporarily or permanently filled with a weighted material such as sand, gravel, or concrete.

Abstract: A vehicle bed liner apparatus includes a peripherally sealed flexible top wall and flexible bottom wall for containing a quantity of ballast liquid, e.g. water. Compartment boundary means are located at plural internal non-peripheral regions between the flexible top wall and the flexible bottom wall. The compartment boundary means are in contact with the flexible top wall and the flexible bottom wall. The compartment boundary means define internal compartment boundaries. The plural non-peripheral compartment boundaries and plural internal non-peripheral regions between the flexible top wall and the flexible bottom wall that are not in contact with the compartment boundaries define plural ballast compartments internal to the wall means. The ballast compartments are in communication with each other. A combination fill and drain valve in the flexible top wall is provided for filling the ballast compartments with a water and for emptying the water from the ballast compartments.

Abstract: The present invention relates to a stabilizing weight assembly for a vehicle, such as a tractor. The stabilizing weight assembly, in one embodiment, includes a weight holder rotatably connected to a weight holder wheel. The weight holder wheel can make contact with the driving surface, depending upon the driving conditions. The stabilizing weight assembly enhances the traction, safety and performance of vehicles such as tractors.

Abstract: A ballast attachment for a tractor three-point hitch includes a cubical, rotational molded polyethylene shell filled with steel reinforced concrete. The front side of the attachment includes a forwardly opening receptacle for receiving a transverse hitch bar carried by the lower links of a tractor three-point hitch, the rear portion of the receptacle including a semi-cylindrical seat for the hitch bar. The center of gravity of the attachment causes the lower part of the attachment to tend to pivot about the hitch bar toward the tractor to the point where it engages the lower three-point hitch draft links. A chain secures the attachment in place.

Abstract: A device for stabilizing a vehicle has a container which is substantially closed and has a size adapted to a corresponding available compartment of a vehicle, the container having walls bounding an inner space, and a body of non-particulate material which fills the inner space of the container to provide a ballast for the vehicle and therefore to stabilize the vehicle.

Abstract: An object is to provide an arrangement which enables the worker to easily carry out checking and maintenance on a part such as an engine from outside in a natural pose without climbing on a counterweight. In a construction vehicle having a traveling vehicle body and a revolving superstructure with an implement, a counterweight installed in the rear of the revolving superstructure comprises a detachable, separable sub-counterweight which is located on the position corresponding to the position of a part requiring maintenance.

Abstract: A ballast weight arrangement for a working vehicle has an interlocking connection between a ballast weight and a ballast weight support in the transverse plane of the vehicle, wherein interlocking is brought about by at least one projection on the ballast weight engaging in a recess on an adjacent ballast weight. Interlocking is achieved by controlled movement of a locking member on lifting up ballast weight 8 from a deposit block 22 and be released on putting down ballast weight 8 on deposit block 22.

Abstract: A low profile, hollow, “H” shaped vessel that, when filled with liquid, greatly enhances traction and handling of rear wheel drive vehicles, by securely adding weight over the drive axel Said vessel (14) is placed in the bed (12) of said vehicle where it straddles the wheel wells (18). Liquid is then added through a fill plug (16) Internal support baffles (22), act to support the entire load surface, while keeping the inertial shift of said liquid to a minimum. Integral tapered ramps (26) ease the loading of cargo, which can be securely tied down to said vessel (14), using the provided tie down slots (24).

Abstract: A low profile, hollow, “H” shaped vessel that, when filled with liquid, greatly enhances traction and handling of rear wheel drive vehicles, by securely adding weight over the drive axel.

Abstract: A ballast weight arrangement for a working vehicle has an interlocking connection between a ballast weight and a ballast weight support in the transverse plane of the vehicle, wherein interlocking is brought about by at least one projection on the ballast weight engaging in a recess on an adjacent ballast weight. Interlocking is achieved by controlled movement of a locking member on lifting up ballast weight 8 from a deposit block 22 and be released on putting down ballast weight 8 on deposit block 22.

Abstract: An apparatus for tuning the weight distribution in a vehicle, typically a high performance automobile, is provided. The apparatus includes a weight tray having an internal passage, a screw element, typically a threaded bolt, that extends into an end of the internal passage, a retainer at the same end of the passage, defining a hole through which the screw is rotatably retained, a primary weight is disposed within the passage and having a bore into which the screw extends and a nut or a threaded portion (i.e., a tapped portion) disposed within the bore that operatively engages the threads of the screw. Additional weights may be attached to the primary weight to increase the weight in the weight tray. The primary and additional weights may further include interlocking portions that are suitably configured to interlock with a corresponding interlocking portion on another weight. One or more of the weights may be assembled from two weight segments to facilitate assembly of the apparatus with minimal tools.

Abstract: A pickup bed ballast assembly for providing added traction while taking up a limited amount of pickup bed space. The pickup bed ballast assembly includes a pair of generally rectangular box shaped main containers and a pair of generally rectangular cover members. Each main container includes a pair of end walls, a first side wall, a second side wall and a bottom wall. Moreover, the main container forms a holding cavity that is used for holding a quantity of sand. The cover members are designed to selectively cover the holding cavities. Each main container is designed to fit over an associated wheel well in a bed of a pickup. In addition, each main container is coupled to the bed of a pickup thereby holding the main container in a static position.

Abstract: A system for providing ballast for cargo bed of trucks consisting of a multiplicity of interlocking low-profile hollow containers interconnectively-assembled across the entirety of a cargo bed of a pickup truck and secured to the bed of the truck with bolts. When the individual containers are filled with a weighted material, such as water or sand, each container preferably will weight less than 50 pounds, and the flat weighted structure provides additional traction to the drive wheels of the truck on slippery road surfaces. In an alternate application, the filled containers are stacked at selective locations and secured to the truck bed to provide a counter-balancing weight for a heavy piece of cargo that is not placed in the gravitational center of the cargo bed.

Abstract: An attachment assembly provides a secure attachment point for the fall arrest tether lines of safety harnesses of workers on flat roofs, the assembly being movable over the roof as required. The assembly can be used alone, but usually is mounted on a wheeled utility cart as employed by roofers to move materials on the roof, or may be an integral part of such a cart. The assembly has a base frame that is spaced from the roof edge over which the worker may fall. An attachment member for tether lines is mounted on the base frame together with at least two longitudinally spaced surface engaging arm, the arms being located at the frame side nearer to the roof edge. When the assembly is in operative position each arm has its lower end, which usually has teeth, close to the roof surface. A counterweight is mounted on the opposite side of the base frame.

Abstract: A traction weight assembly, for mounting traction weights on a utility vehicle, has a weight bar that is inserted into a tubular receptacle. The tubular receptacle is secured to the vehicle frame. A retainer pin is inserted through a retainer pin passage through the tubular receptacle and an aligned adjustment bore through the weight bar. Traction weights are mounted on a portion of the weight bar that extends to the rear of the tubular receptacle. A retainer plate is attached to the weight bar by at least one bolt that clamps the traction weights between the tubular receptacle and the retainer plate. If needed a spacer is provided between the tubular receptacle and the traction weights.

Abstract: A traction enhancing ballast device for use in the cargo compartment of a vehicle is disclosed. The device includes a pair of hollow ballast container members, each one fastened to a flat anchor plate on opposite ends of a telescoping bracing bar member. The ballast containers each have a hinged top lid for adding and removing ballast, such as sand, to the container. The container has a curved end that fits against the wheel well of a vehicle. The device is mounted behind the wheel wells in the cargo compartment of a vehicle with the bracing bar member extended to hold the containers against the sidewalls of the cargo compartment. The device is locked in place by inserting a pin member through aligned apertures in the telescoping bracing bar member. The end of the container opposite the curved end has a spout that is used to empty the ballast contents of the containers when not in use.

Abstract: A counterweight system for a lift-type vehicle, which includes a lifting arrangement for lifting a load at one end of the vehicle, includes a counterweight compartment located at an opposite end of the vehicle. The vehicle includes a set of ground-engaging wheels, and the lifting arrangement is located on one side of the set of wheels and the counterweight compartment is located on the other side of the set of wheels. The lifting arrangement includes a boom assembly mounted for pivoting movement between a pair of uprights located toward the same end of the vehicle as the counterweight compartment. The uprights are constructed to provide a first amount of counterweight to the vehicle, to provide a first lifting capacity for the vehicle. The counterweight compartment is located between the uprights, and one or two counterweights can be received within the counterweight compartment.

Abstract: A tractor for use with a front loader connected thereto has a pair of mast mounts for detachably attaching right and left masts of the front loader, a pair of braces for coupling the mast mounts to the tractor, and a weight mount for carrying a plurality of weights. The braces have distal ends thereof connected to the weight mount. A spacing L1 between the distal ends of the braces is smaller than a spacing L2 between proximal ends thereof. Consequently, the braces are arranged to avoid their interference with front wheel steering. With the weight mount acting also as a brace support, the weight mount has an increased supporting strength.

Abstract: A ballast system comprising an I-beam shaped molded member having a hollow inner chamber accessible through a fill cap and drain plug and including a molded contoured bottom section molded to fit into the recesses formed into the upper surface of the ballast member. The recesses formed into the upper surface serve as storage spaces for tools and supplies.

Abstract: A vehicle traction enhancing apparatus is provided having a rectangular base designed to fit between the wheel wells of a vehicle cargo area with extensions in juxtaposition with the front and rear faces of the wheel wells. The base is constructed of four restraint members welded together and sized to hold an array of concrete/cinder blocks over the rear axle of the vehicle. A removable rack fits into sockets, and supports construction sheets, such as wall board, plywood, ladders, lumber or the like. An auxiliary holder for round containers may be attached to the base or an extension member.

Abstract: A ballast receptacle is provided to increase the load on the rear wheels of a vehicle such as a pick-up truck. The receptacle includes a container formed from a plastic material such as vinyl and can be filled with water to increase the vehicle's traction on slick surfaces such as ice or mud covered roads. The ballast receptacle is positioned laterally at the rear of the vehicle bed and is releasably anchored by flexible straps to each side of the vehicle.

Abstract: The invention provides a self-mounting counterweight device which is mounted to one end of the chassis frame of the vehicle. The counterweight is U-shaped having two vertical sides and an outward wall defining an internal enclosure. The counterweight includes a rod mounted to the top of the counterweight for suspending it from a boom and includes lateral threaded bolts to releasably mount the counterweight to blocks on the chassis frame. The lifting boom has an inward end journalled to the frame and an outward end with tackle for releasably connecting the boom outward end to the counterweight suspending rod. A hydraulic cylinder provides mechanical lift with an inward end journalled to the frame and an outward end pivotally connected to the boom. The combination of the boom and lift provides a scissor-like lever for selectively raising and lowering the counterweight between a lowered and mounted position.

Abstract: A front end bumper assembly for tractors is constructed from hollow steel fluid reservoir tanks for providing ballast. The bumper assembly has an upper grille for protecting the nose-radiator region of the tractor and two spaced lowermost horizontally disposed bumper arms. The bumper assembly is attached to a tractor by a bracket assembly at a location below the center of gravity of the tractor to concentrate the bumper weight for bearing upon front steering wheels for better traction and steering.

Abstract: A supplementary weight for ballasting a work vehicle includes locating pins which project therefrom. The weight has a pin bore which receives the locating pins and the locating pins are at least partially retractable into the weight. The supplementary weight is preferably comprised of a plurality of partial weights, each having a pin bore extending therethrough, and a central tube is received by the pin bores and couples the partial weights together, the locating pins being adjustably mounted in the central tube. A central tube extends through the pin bore which extends through the supplementary weight, and clamping devices are attached to ends of the central tube for clamping the supplementary weight on the central tube. Recesses are formed in outer side surfaces of the supplementary weight and the clamping devices are located at least partially within the recesses.

Abstract: A supplementary weight for ballasting a vehicle can be adapted to be hooked onto a carrier component. The weight includes an entry opening which is bordered by an upper leg and a lower leg. The upper leg is supported on the carrier component which projects into the entry opening. Generally vertical bores extend in the upper leg and the lower leg, and the leg bores are aligned with a corresponding vertical bore in the carrier component. An attaching bolt is received by these bores when the weight is mounted on the carrier component. The attaching bolt has a head, a shank and a threaded section. The attaching bolt is screwed into an axially movable tensioning device which is mounted inside the lower leg, thus clamping the carrier component to the upper leg.

Abstract: A truck bed ballast apparatus includes a container assembly and a foot assembly adapted for connection to a truck bed. An inlet aperture is located on a wall of the container assembly. A quantity of sand can be added to the container assembly through the inlet aperture. A cover assembly covers the inlet aperture for retaining the sand inside the container assembly. The container assembly is adapted to be juxtaposed to a fender well projecting upward from the truck bed adjacent to a side wall of the truck bed. The foot assembly includes a plurality of apertures adapted to receive connectors for connecting the container assembly to the truck bed. In one embodiment, the container assembly includes a fender-well shaped outer portion adapted to fit over a fender well.

Abstract: Counterweights are useful in stabilizing a work machine to increase the traction to a pair of wheels on one end when a implement is attached to the opposite end of the machine. The subject counterweight arrangement includes a base weight which is removably attached to the machine frame. A plurality of add-on weights are removably attached beneath the base weight by a u-shaped bolt. This arrangement of components provides a simple compact structure to counteract the weight of the implement attached to the opposite end of the machine and also provides a way to add or subtract weight to offset the the addition or subtraction of mechanisms to the end of the backhoe stick assembly.

Abstract: A skate having a damping mechanism secured thereto to reduce the harmful vibrational stress from being transmitted through the skate to the wearer's leg.

Abstract: An apparatus for providing weight over the driven wheels of a motor vehicle. The apparatus includes a plurality of elongated containers for holding material. The material provides adjustable weight to the vehicle. The containers are installed on the floor of a normal cargo area of the vehicle. Also included are removable end covers located at one or both ends of the elongated containers for filling and emptying the containers with weighted material. A bracket is provided for holding the elongated containers with their installed end covers onto the floor of the vehicle to prevent movement of the containers with respect to the floor.

Abstract: A tractor having a front axle that pivotally moves laterally in response to a corresponding steering action of the steerable wheels mounted on the front axle is disclosed wherein the ballast assembly is supported directly by the front axle so as to be laterally movable relative to the chassis with the shiftable front axle. The ballast assembly is formed by individual weights mounted on an arcuate rack detachably connected to the front axle. The individual weights are connected together by fasteners to form a unitary package positioned centrally between the steerable wheels.

Abstract: A suitcase weight for use in forming a ballast assembly for the front of an agricultural tractor is disclosed wherein the weight has a body member including a rearward portion adapted for support on a carrier detachably connected to said tractor. Each individual weight further has an upper and lower fastener opening forming a transversely extending passageway for the insertion of a fastener from each side of the ballast assembly for engagement with a fastener strip inserted through flutes formed in the body member and extending vertically from each of the fastener openings. Each weight is thicker at the forward end than at the rearward end to form an arcuate ballast assembly when the weights are clamped together.

Abstract: A motor vehicle trailer is provided with counterbalancing weights and a plurality of recesses formed in the floor of the trailer for engaging the counterbalancing weights. The weights can be positionally interchanged among the recesses so as to counterbalance the contents of the trailer and provide stability in use. A carriage for a boat hull upside down atop the trailer, rear access to the trailer interior, and an openable top in the form of a roller blind are included.

Abstract: A bed liner for a pickup truck cargo area is disclosed wherein a ballast means is disposed about said liner in advantageous positions. An upper bed liner is mounted on the side wall of the pickup truck and compatibly retains a ballast media. Further, a floor bed liner incorporating a ballast means is disclosed.

Abstract: A crawler tractor is disclosed with a counterweight assembly which affords optimum weight distribution and traction for operation on steep slopes and grades. The assembly includes a counterweight body having a shank which is carried by a housing mounted by a support arm weldment on the rear end of the tractor. The shank is releasably engaged with the housing. Hydraulic actuators are provided to move the counterweight to a lowered position for backing the tractor uphill, and for raising the counterweight for dozing in a downhill direction. One embodiment provides for selective fore and aft positioning of the counterweight relative to the tractor in accordance with operating conditions.

Abstract: This invention is puzzle shaped units that preferably are filled with concrete or sand and interlocked in such a way as to form one ballast unit that will lay flat on the floor of a vehicle's normal cargo carrying area. These puzzle shaped units can be arranged in many ways to best fit the cargo space and ballast weight requirements of any vehicle. They are made in such a way and of such a weight that they are easy to take in and out as the need arises.

Abstract: Front end loader mounting structure including a rear support assembly for receiving pivot tubes located at the lower ends of the rear upright mast posts. A round cross tube connecting the forward ends of the mast arms is rotatable upwardly through an arc-shaped path with center of radius of the path located on the axis of the pivot tubes. The cross tube is received within an inverted cradle assembly located directly in the path and is releasably locked in a raised mounted position within the cradle assembly by latching structure remotely actuated from the tractor cab. The mast posts include downwardly extending projections which are freely received by the support assembly when the loader is in the stored position but which rotate against a locking block to secure the posts tightly to the tractor frame as the mast arms approach the upwardly rotated position.

Abstract: A traction weight system comprised of a plurality of generally rectangular cast metal plates sized so as to be arranged in a variety of two dimensional arrays to comport with the dimensions of different vehicle cargo compartments, each plate having means to interlock that plate with those adjacent plates along or across their closely confronting edges. The plates may be interlocked by various means, including integral tongue and groove structures formed in each plate, or a series of aligned notches which may receive coupling pins. Each plate preferably has a height dimension substantially less than its width or length dimensions, so that the plates may be arranged across the floor or bed of the cargo compartment without interfering with the normal uses of that cargo compartment for storing or transporting cargo.

Abstract: A load handling vehicle equipped with a load handling device comprises a pair of reinforcing frames attached to opposite sides of the vehicle body, a steering panel, a front cover covering the space under the panel from the front and a protective device covering the operator's seat and including a pair of opposite front posts connected to the frames in front of the seat. Each of the front posts comprises a lower post member extending upright from the frame and positioned in the vicinity of of the front cover, and an upper post member removably attached to the lower post member. The steering panel and the front cover are attached to the pair of lower post members and can therefore be fixed in place by a simple arrangement and yet with increased strength. When unnecessary, the protective device is removable with the panel and the cover fixed in place.

Abstract: A hollow compartment is formed in the bottom wall of the present truck bed protective liner and defines a ballast chamber to permit inserting liquid ballast in the ballast chamber when it is desired to provide additional weight on the rear portion of the truck and also permitting removal of the liquid ballast from the ballast chamber when it is desired to reduce the weight on the rear portion of the truck. The hollow compartment is preferably provided by spaced-apart upper and lower bottom wall members extending substantially throughout the width and length of the protective liner and being joined along their front and side edges to the corresponding front and side walls of the protective liner. A rear wall is joined to the upper and lower bottom walls of the opposed side walls of the liner to completely enclose the ballast chamber.