Universal dumpster

A universal dumpster adapted for use with both front loading and roll-off refuse collection trucks includes a floor, side walls and end walls. The floor, side walls and end walls together define an interior compartment for collecting and containing solid waste. Sleeves rotatably mounted to the side walls engage the lifting arms of a front loading truck to lift and tilt the dumpster above the hopper. A mechanical stop is provided on the side walls that engages the distal end of the lifting arm to thereby reduce the stress exerted on the lifting arm. One of the end walls is formed by an upper door and a lower door having side panels to contain and direct the refuse into the hopper. A safety lock is provided on the side walls that engages the corresponding sleeve to limit over travel so the dumpster does not tip over the front loading truck.

FIELD OF THE INVENTION

The invention relates to a dumpster for collecting, containing and controlling solid waste at a refuse collection site. More particularly, the invention is a universal dumpster adapted for use with both a front loading and a roll-off refuse collection truck.

BACKGROUND OF THE INVENTION

Proper collection, containment, control, transportation and disposal of solid waste are necessary for protecting public health and safety and for promoting a clean environment. Containers, commonly known as dumpsters, that hold large quantities of solid waste generated at multifamily residential, institutional, commercial, industrial, and construction sites, are an important tool in the management of solid waste.

There are at least two types of dumpsters for handling solid waste, the “front loader” dumpster and the “rear loader” dumpster. Present dumpster designs incorporate several common features including: a floor, side walls, and end walls which together define an interior compartment; openings through which solid waste is placed into the interior compartment; openings through which the solid waste is discharged out of the interior compartment; and means for supporting the dumpster while the solid waste is being discharged.

The front loader type dumpster is typically used at multifamily residential and light commercial sites and is provided with sleeves fixed to the exterior of the side walls to receive the lifting arms of a front loading truck. The front loading truck approaches the front loader dumpster and positions the arms of the truck within the sleeves of the container. The driver then activates a hydraulic system which lifts the dumpster over the cab of the truck and rotates it to a substantially inverted position to discharge the solid waste into a larger container on the back of the truck, generally referred to as a hopper. Next, the driver lowers the empty dumpster and withdraws the lifting arms of the front loading truck from the sleeves. The driver may then activate a compactor blade in the hopper to compact the solid waste and thereby increase the amount of solid waste that the hopper can accommodate. The front loading truck then travels to the location of the next front loader dumpster to repeat the procedure until the hopper is full. Once the hopper is full, the front loading truck travels to a disposal site, such as a landfill, to dispose of the solid waste.

The rear loader type dumpster is larger than a front loader type dumpster and is typically used at heavy commercial, industrial and construction sites. Rather than being emptied into the hopper of a front loading truck, the rear loader dumpster is pulled onto the bed of a roll-off truck and transported to the disposal site. A typical roll-off truck is equipped with a winch and roller system which positions the dumpster onto the bed of the truck for transportation to the disposal site. Once at the disposal site, the bed and dumpster are tilted so that the solid waste is discharged through one or more rear doors provided in the end wall of the dumpster, much like a dump truck. After being emptied, the rear loader dumpster is returned to the same or a different refuse collection site.

Utilizing different types of dumpsters which each require a different method of discharging the solid waste reduces both the cost effectiveness and the efficiency of solid waste collection. Conventional front loader type dumpsters are relatively small and are not provided with a door in an end wall of the dumpster. Furthermore, because the solid waste in a conventional front loader dumpster must be discharged through an opening in the top of the dumpster, it cannot be emptied by a roll-off truck. Conventional rear loader type dumpsters are wider than front loader type dumpsters and are not provided with sleeves. As such, a rear loader dumpster cannot be emptied by a front loading truck. Accordingly, solid waste collection would be more cost effective and efficient if the two types of dumpsters could be combined into a single universal dumpster which can be emptied by either a front loading truck or a roll-off truck.

A major environmental concern is the accidental dispersal of solid waste from a front loader dumpster while the solid waste is being discharged into the hopper of the front loading truck. For example, a sudden gust of wind may disperse some of the solid waste onto the ground surrounding the front loading truck as the front loader dumpster is being emptied. Front loader dumpsters are discharged at refuse collection sites that are typically located in areas where people live and work. Thus, the solid waste that is accidentally dispersed has a negative impact on the public health and safety, as well as the local environment.

Conventional designs for front loader dumpsters pose additional safety concerns. The sleeves of a front loader dumpster that engage the lifting arms of a front loading truck are typically welded onto the exterior surface of the side walls of the dumpster. Because the solid waste in a conventional front loader dumpster is discharged through an opening in the top, the dumpster must be completely inverted to discharge all of the solid waste from the interior compartment. Completely inverting the dumpster induces shock stresses on the welds holding the sleeves to the side walls because the weight of the dumpster suddenly shifts from the top of the sleeves to the bottom of the sleeves as the dumpster is inverted. Over time, the welds holding the sleeves to the side walls can weaken and ultimately break from repeated emptying of the dumpster. As a result, the dumpster could fall onto the front loading truck as it is being inverted to discharge the solid waste, potentially injuring workers or passersby.

In addition to posing a safety hazard, the shock stresses induced on the sleeve welds reduce the efficiency of front loading trucks. The lifting capability of late model front loading trucks usually exceeds the weight capacity of a front loader dumpster. However, because of the danger of the sleeves breaking away from the side walls, the usable volume of a front loader dumpster is limited by a safety factor. If front loader dumpsters were provided with doors in one of the end walls for discharging solid waste, they would not have to be completely inverted to discharge all of the solid waste from the interior compartment of the dumpster. Eliminating the need to completely invert the dumpster would significantly reduce the shock stresses on the welds holding the sleeves to the side walls induced by the sudden shifting of the weight of the dumpster on the sleeves. As a result, dumpsters capable of containing a larger volume of solid waste could be utilized with front loading trucks,

For the foregoing reasons, it is apparent that a need exists for a universal dumpster that can be emptied by either a front loading truck or a roll-off truck. A need also exists for a universal dumpster that minimizes, and preferably eliminates, the accidental dispersal of solid waste into the environment during discharge of the solid waste into the hopper of a front loading truck. Finally, there exists a need to increase both the safety of front loader dumpsters and the efficiency of front loading trucks and dumpsters.

SUMMARY OF THE OBJECTS OF THE INVENTION

Accordingly, it is a principal object of the present invention to provide a universal dumpster that is designed and constructed in such a way that it may be emptied by either a front loading truck or a roll-off truck.

It is a further object of the present invention to provide a universal dumpster that minimizes the environmental damage caused by the accidental dispersal of solid waste during discharge of the solid waste into the hopper of a front loading truck.

It is a further object of the present invention to provide a universal dumpster that is designed and constructed to be emptied by a front loading truck without inducing significant shock stresses on the welds which hold the sleeves to the side walls of the dumpster.

It is a further object of the present invention to provide a universal dumpster that is designed and constructed to be emptied by a front loading truck without exerting excessive forces on the lifting arms of a convention front loading refuse collection vehicle at the beginning of the lifting process.

It is a further object of the present invention to provide a universal dumpster that has an expandable volume.

It is a further object of the present invention to provide a universal dumpster having sufficient lids and doors conveniently located on the dumpster so that solid waste may be placed in all areas of the interior compartment of the dumpster.

SUMMARY OF THE INVENTION

The above objects and others are achieved by a universal dumpster constructed in accordance with the present invention. A universal dumpster according to this invention includes a floor having interior and exterior surfaces. A pair of side walls extend upwardly and generally perpendicularly from the floor. Likewise, a pair of end walls extend upwardly and generally perpendicularly from the floor. The end walls are also generally perpendicular to and attached to the side walls. The floor, side walls and end walls together define an interior compartment for collecting and containing solid waste. A sleeve is fixed to each side wall to engage the pickup arm of a conventional front loading refuse collection vehicle. At least one of the end walls of the dumpster includes at least one door which is movable between a first fully closed position and a second fully opened position which exposes an opening through the end wall for depositing solid waste into the dumpster and discharging the solid waste from the dumpster.

In one preferred embodiment of the invention, the end wall is formed by a downwardly opening lower door hingedly attached to the floor and having a front panel and a pair of side panels. The front panel and the side panels form a discharge chute when the lower door is in the second fully opened position. In another preferred embodiment, the end wall is formed by a pair of front doors that are movable between a first fully closed position and a second fully opened position. In the fully opened position, the doors form a discharge chute. Each door is hingedly attached to one of the side walls and has a floor panel extending from the base of the door. In another preferred embodiment, the end wall is formed by a pair of front doors that are hingedly attached to a telescoping discharge chute. The telescoping discharge chute is formed by a floor ramp extension panel and side wall extension panels extending upwardly and generally perpendicularly from the floor ramp extension panel. The telescoping discharge chute is attached to the dumpster by at least one telescoping rod.

In addition, the dumpster may be constructed with or without a lid. A lid for a dumpster according to this invention is formed by at least one door which is movable between a first fully closed position and a second fully opened position which allows access to the interior compartment of the dumpster for depositing solid waste. Likewise, at least one of the side walls of the dumpster may be provided with a door that allows access to the interior compartment of the dumpster for depositing solid waste. In yet another preferred embodiment, the dumpster may include at least two wheels attached to the floor of the dumpster and a removable trailer hitch. The wheels and the trailer hitch permit the dumpster to be moved to a location that is accessible to a conventional refuse collection vehicle. In yet another preferred embodiment, the dumpster may include a pair of movable sleeves for reducing the forces exerted on the lifting arms of a conventional front loading refuse collection vehicle at the beginning of the lifting process, thereby further increasing the capacity of the dumpster.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A number of preferred embodiments of the present invention will be described more fully hereinafter. However, the invention should not be construed as being limited to the embodiments described herein. Rather, it is intended that the invention be construed broadly to encompass any and all embodiments of a dumpster having the disclosed features, or equivalents thereof, which are within the skill of an ordinary person in the relevant art. In the description, like reference numerals designate like or corresponding parts throughout the several figures. It is to be also understood that such terms as “front”, “rear”, “top”, “floor”, “side”, and “end” are used in the description for purposes of locating one element relative to another and are not to be construed as limiting terms. Finally, it should be understood that the illustrations provided in the figures are for the purpose of describing various exemplary embodiments of the invention, and thus, are not intended to limit the scope of the invention in any manner.

Referring now to the accompanying figures, the invention is a large container, hereinafter referred to as a dumpster, indicated generally at30, for the efficient collection, containment, and control of solid waste material. In the broadest sense, the dumpster30comprises a floor40, opposed side walls50, and opposed end walls60. The floor40, side walls50and end walls60together define an interior compartment of the dumpster30for collecting and containing the solid waste. Dumpster30is generally rectangular, but may be constructed to any size and shape which will contain the solid waste efficiently and accommodate the conventional apparatus for compacting and discharging the solid waste from the dumpster. While dumpsters are generally made of a rigid metal, such as steel, the dumpster30of the present invention may be made of any rigid and durable material. The floor40, the side walls50and the end walls60are preferably thin and lightweight to permit conventional refuse collection vehicles to lift and transport as much solid waste as possible. However, the dumpster30must also be strong and durable enough to withstand repeated lifting, transportation and discharge of the solid waste, as well as prolonged exposure to the elements.

The floor40comprises floor plate42that is raised above the ground by support feet44attached to the underside of the floor plate42. At least one hook46is also attached to the floor plate42adjacent to at least one of the end walls60for pulling the dumpster30onto a roll-off truck R, as illustrated inFIG. 14. The hook46is engaged by a conventional winch which pulls the dumpster30onto the bed of the roll-off truck R, As the dumpster30is pulled onto the bed of roll-off truck R, the support feet44engage rollers which assist the winch in positioning the dumpster30on the truck R and support the dumpster30during transportation. The support feet44and hook46may be attached to the floor plate42by any conventional means, such as welding, which provides a rigid and durable attachment. The floor40further comprises a ramp48that slopes upwardly from a medial point on the top side of the floor plate42in the direction of one of the end walls60to facilitate emptying of the solid waste, as will be described hereinafter.

The side walls50extend upwardly and generally perpendicularly from the floor40. Preferably, at least one of the side walls50has an opening52formed therein (FIG. 3A) which provides access to the interior compartment of the dumpster30for depositing the solid waste. More preferably, a door54may be provided that is movable from a fully closed position covering the opening52to a fully opened position exposing the opening52. The door54may be provided with a handle55to facilitate movement between the fully closed position and the fully opened position. The door54is preferably biased in the closed position since it is desirable to cover the opening52while the dumpster30is being transported or emptied. As is shown inFIGS. 9–11, the side walls50may comprise angled side portions51which taper inwardly to form a neck having a width narrower than that of the remainder of the interior compartment of the dumpster30. The neck allows a dumpster30having the width of a conventional rear loading dumpster to be emptied into the hopper of a conventional front loading truck F.

A pickup sleeve56is fixed to each side wall50. The sleeves56are constructed to accommodate the lifting arms A of a conventional front loading truck F (FIG. 6). In some exemplary embodiments, the pickup sleeves56are positioned on the exterior surface of the side walls50adjacent the floor40of the dumpster30and flush with one of the end walls60of the dumpster30(FIG. 1–4,6–8B,15–16,19–20). In other exemplary embodiments, the sleeves56are positioned on the interior surface of the side walls50in the space between the floor ramp48and the floor plate42(FIGS. 9–11,12–13,23–24). The pickup sleeves56may be fixed to the side walls50by any conventional means, but preferably are welded to the exterior or interior surface of the side walls50.

As best shown inFIGS. 1 and 2, in a preferred embodiment of the invention at least one of the end walls60is formed by an upwardly opening upper door62and downwardly opening lower door64. Each of the doors,62,64is movable between a fully closed and a fully opened position. The upwardly opening upper door62hangs between the ends of the side walls50from a lateral hinge61. Handle63enables a user to open upper door62for the purpose of placing solid waste into the dumpster30. Upper door62is biased in the closed position by gravity. However, hinge61may also be provided with a torsion spring (not shown) for biasing upper door62in the closed position. Downwardly opening lower door64comprises a front panel64aand side panels65that overlap the exterior surface of side walls50when the lower door64is in the fully closed position. The lower door64is biased in the closed position by a pre-tensioned torsion spring66located along the hinge line formed between the lower door64and the floor40of the dumpster30. Detent latches67may be attached to the exterior surface of the side walls50to insure that the lower door64remains in a closed position until the dumpster30is lifted and tilted by a front loading truck F to be emptied. When the dumpster30is tilted, the lower door64opens automatically under the weight of the solid waste in the interior compartment of the dumpster30. A discharge chute, for directing the solid waste from the interior compartment of the dumpster30into the hopper H of the front loading truck F (FIG. 7), is formed by the front panel64aand the side panels65of the fully opened lower door64. The upper door62also opens when the dumpster30is lifted and tilted into position for emptying. Preferably, when the lower door64is in the fully opened position, the angle of the front panel64arelative to the floor40of the dumpster30corresponds to the angle of the ramp48relative to the floor40. Thus, the front panel64aforms a straight line with the ramp48, as shown inFIG. 3B. Preferably, at least one stop68is provided on the dumpster30to prevent the lower door64from opening beyond the point where the front panel64aand the ramp48form a straight line. The stop68may be fixed to the floor40of the dumpster30, as shown inFIG. 1, or may be fixed at any other convenient location on the dumpster30.

A rear view of the same embodiment of the invention is shown inFIGS. 4,5A and5B. In the rear view it is apparent that at least one of the end walls60is formed by a pair of large rear doors70attached to the side walls50by opposed vertical hinges72. Preferably, each of the large rear doors70is biased in the closed position by a pre-tensioned spring located along the hinge line formed between the side wall50and the end wall60. Preferably, each of the rear doors70has an opening73formed therein (FIG. 5A) for providing access to the interior compartment of the dumpster30to deposit the solid waste. The opening73is covered by a small inset door74that is movable between a fully closed position and a fully opened position. Preferably, hinges75provided between the rear doors70and the inset doors74are angled relative to vertical to bias the inset doors74in the closed position. A handle76may also be provided to assist in opening the inset door74.

The exemplary embodiment of the universal dumpster30described above has at least three advantages. First, the open upper door62and the open lower door64define a funnel that directs the solid waste into the hopper H of the front loading truck F. The funnel prevents the solid waste from being accidentally dispersed into the surrounding environment as the dumpster30is being emptied into the hopper H of the front loading truck F, as illustrated inFIG. 7. Second, because the dumpster30is emptied through an end wall60instead of through the top, the dumpster30empties with a reduced lifting angle L relative to horizontal. More specifically, the front loading truck F does not have to rotate the dumpster30to a substantially inverted position as is required with a conventional front loader dumpster. Accordingly, the lifting angle L generates little or no torque reversal. As a result, the dumpster30may be made considerably larger than a conventional front loader dumpster. Third, the universal dumpster30of this embodiment may be emptied from either end by a conventional roll-off truck R, as illustrated inFIGS. 8A and 8B.

Another exemplary embodiment of the invention is shown inFIGS. 9–11. As previously mentioned, angled side portions51of side walls50allow dumpster30having the width of a conventional rear loading dumpster to be emptied into the hopper H of a conventional front loading truck F. This embodiment utilizes pick up sleeves56positioned on the interior surface of side walls50in the space between the ramp48and the floor plate42. In order to accommodate the sleeves56, the space between the ramp48and the floor plate42is enlarged by the addition of a ramp portion48a. Ramp portion48ais positioned at less of an angle relative to the floor40than that of ramp48. Preferably, when the downwardly opening lower door64is in the fully opened position, the angle of the front panel64arelative to the floor40corresponds to the angle of the ramp portion48arelative to the floor40. Side panels65of lower door64overlap the interior surface of side walls50of the dumpster30.

Another exemplary embodiment of the invention is shown inFIGS. 12 and 13. This embodiment also utilizes a downwardly opening lower door64comprising side panels65that overlap the interior surface of side walls50of the dumpster30.

Another exemplary embodiment of the invention is shown inFIGS. 15–18. In this embodiment, at least one of the end walls60of the dumpster30is formed by a pair of large front doors80attached to the side walls50by vertical hinges82such that the doors80are movable between a fully closed position and a fully opened position. Preferably, each door80is biased in the closed position by one or more pre-tensioned torsion springs83located along the hinge line formed between the side wall50and the end wall60. Each door80comprises an arcuate floor panel84attached to the base of the door80at an angle relative to the floor40that corresponds to the angle of the ramp48relative to the floor40of the dumpster30. When the doors80are in the fully opened position, the floor panels84overlap one another to form an extension of the ramp48. In the closed position, the floor panels84retract into the open space85between the ramp48and the floor plate42, as best shown inFIG. 17. In the fully opened position, the ramp48, doors80and floor panels84define a funnel for discharging the solid waste from the interior compartment of the dumpster30, as previously described.

Another exemplary embodiment of the invention is shown inFIGS. 19–22. In this embodiment, at least one of the end walls60is formed by a pair of large front doors90. The doors90are attached to side wall extension panels92by vertical hinges94such that the doors90are movable between a fully closed position and a fully opened position. Preferably, each door90is biased in the closed position by one or more pre-tensioned torsion springs95located along the hinge line formed between the side wall extension panel92and the door90. Each side wall extension panel92is attached along its base to a floor ramp extension panel96. The side wall extension panels92are connected to telescoping rods97which slide between a fully extended position and a fully retracted position to allow the side wall extension panels92and the floor ramp extension panel96to alternatively telescope outwardly from the dumpster30and retract back into the interior compartment of the dumpster30. The telescoping rods97are mounted for movement in sleeves98that are fixed to the exterior surface of side walls50of the dumpster30. Preferably, each of the telescoping rods97is biased in the fully retracted position by a coil spring99. The end of the rod97is provided with a stop97ato prevent the side wall extension panel92from extending too far. In the fully retracted position, the side wall extension panels92overlap the interior surface of the side walls50and floor ramp extension panel96overlaps the interior surface of the ramp48so that the dumpster30is available for receiving solid waste in the interior compartment. As the dumpster30is tilted for emptying, the side wall extension panels92and the floor ramp extension panel96slide outwardly from the dumpster30as a unit. Once the side wall extension panels92and the floor ramp extension panel96are fully extended, the doors90open outwardly under the weight of the solid waste being discharged from the dumpster30. Together, the side wall extension panels92, the floor ramp extension panel96and the doors90form a telescoping discharge chute for guiding the solid waste out of the interior compartment of the dumpster30.

Preferably, dumpster30has a removable lid100which can be opened to allow access to the interior compartment of the dumpster30from above and can be closed to prevent refuse from blowing out of the dumpster30during transportation and during discharge of the solid waste from the interior compartment of the dumpster30. In one embodiment, the lid100comprises a pair of hinged top doors102. The top doors102may be hinged at the end walls60or may be hinged at a medial location between the end walls60of the dumpster30. Each top door102of the lid100opens upwardly to allow access to the interior compartment of the dumpster30to deposit the solid waste. One or both top doors102of the lid100may also be removed entirely to allow the dumpster30to be utilized, for example, at a construction site to collect and contain large articles of debris, such as building materials. The dumpster30may be constructed without any lid100as shown inFIG. 12. However, the absence of a lid100increases the likelihood that solid waste will be accidentally dispersed during discharge of the solid waste into the hopper H of a front loading truck F, or during transportation by a roll-off truck R. In another exemplary embodiment shown inFIG. 13, the lid100of the dumpster30comprises a pair of top doors106hinged along the side walls50of the dumpster30. This alternative embodiment allows use of the dumpster30at a construction site, or at another site where large articles of solid waste are generated, without having to remove any portion of the lid100.

In another exemplary embodiment, shown inFIGS. 23 and 24, the dumpster30comprises a removable lid110for expanding the usable volume of the dumpster30. The lid110comprises end walls112, side walls114and a pair of top doors116. A retaining leg118provided at each bottom corner of the lid110cooperates with a hollow corner post120provided at each upper corner of the dumpster to secure the lid110on the dumpster30. A removable end wall cross bar122is also provided to support the end walls60of the dumpster30when the lid110is not in use. The cross bar122may be removed to prevent solid waste from catching between the hinged lower door64and the hinged end wall112during discharge when the lid110is in use. The end walls112and the side walls114of the lid110may be adapted for use with any of the exemplary embodiments of the invention shown and disclosed herein.

In some situations, it may be convenient to locate a dumpster30in a place that is not readily accessible to either a front loading truck F or a roll-off track R. To accommodate these situations, the dumpster30could be fitted with wheels130and a removable trailer hitch132as shown inFIG. 25. The wheels130and removable trailer hitch132permit the dumpster30to be moved to a location that is accessible to the refuse collection trucks so that the dumpster30may be emptied.

In yet another exemplary embodiment shown inFIGS. 26–29, the dumpster30reduces the forces exerted on the lifting arms A of a conventional front loading truck F. The dumpster30is substantially identical to the dumpster shown inFIGS. 1–8Bexcept that the floor40does not comprise ramp48sloping upwardly from a medial point on the top side of the floor plate42in the direction of one of the end walls60. As a result, the torsion spring66is located nearer to the ground. Accordingly, the front loading truck F is not required to rotate the dumpster30nearly as far to discharge solid waste from the interior compartment of the dumpster30into the hopper H of the front loading truck F (FIG. 29). In addition, the pickup sleeves156are rotatably mounted to the exterior surface of the side walls50adjacent the floor40of the dumpster30. The pickup sleeves156may be rotatably mounted to the side walls50in any known manner. As shown, each pickup sleeve156comprises a triangular shaped pivot160mounted on a cylindrical trunnion pin162projecting outwardly from the side wall50. Sleeves156are interconnected by a relatively large diameter sleeve bar164extending transversely between the side walls50such that sleeves156and sleeve bar164form a generally U-shaped lifting tongue.

As previously described, the sleeves156are constructed to engage the lifting arms A of a conventional front loading truck F (FIG. 27). However, because the sleeves156are rotatably mounted to the side walls50, the sleeves156will be contacting the ground when the lifting arms A initially engage the sleeves156of the dumpster30(FIG. 27). As the lifting arms A fully engage the sleeves156and begin to lift the dumpster30, the sleeves156rotate about the pivots160on the trunnion pins162. As a result, the dumpster30is dragged in the direction of the front loading truck F until the sleeve bar164contacts feet44on the underside of the floor40of the dumpster30. Rotation of the sleeves156is terminated once the dumpster30has been lifted by the front loading truck F approximately sixty degrees relative to horizontal, as depicted by the broken lines inFIG. 28. The front loading truck F continues to lift the dumpster30upwardly and rearwardly so that the dumpster30is substantially horizontal above the front loading truck F, as depicted by the broken lines inFIG. 29.

It should be noted that because the sleeves156are rotatably mounted to the side walls50, the elevation of the dumpster30above the front loading truck F is reduced compared to the elevation of the dumpster30, as depicted inFIG. 7. Accordingly, the center of gravity of the dumpster30is closer to the front loading truck F at both the beginning and during the initial stage of the lifting process, and less force is therefore exerted on the lifting arms A. As a result, the capacity of the dumpster30may be increased somewhat. The lifting arms A continue to lift and tilt the dumpster30rearwardly approximately 105 degrees until the weight of the solid waste in the interior compartment of the dumpster30automatically opens the lower door64against the torsion spring66, as previously described. The lower dumping position, as depicted by the solid lines inFIG. 29, permits the solid waste in the interior compartment of the dumpster30to be discharged deeper into the hopper H of the front loading truck F.

In yet another exemplary embodiment shown inFIGS. 30–33, the dumpster30further reduces the forces exerted on the lifting arms A of a conventional front loading truck F and further minimizes the likelihood that refuse will be inadvertently dispersed into the environment while the dumpster is being raised and tipped above the hopper of the front loading truck F. At the same time, the amount of travel of the dumpster30relative to the front loading truck F is limited so that the dumpster30cannot tip over the truck F. In addition, the embodiment of the dumpster30shown inFIGS. 30–33permits operation of the packer blade inside the hopper H of the front loading truck F even when the dumpster30is in the raised and tipped position above the hopper H. The dumpster30is substantially identical to that shown inFIGS. 26–29except that one or more mechanical stops170are provided to engage the lifting arms A of the front loading truck F and thereby reduce the amount of stress exerted on the pivots160and trunnion pins162when the dumpster30is raised and tipped above the hopper H of the front loading truck F, as will be described. Furthermore, the upper door62and the lower door64are configured to further contain the refuse and to reduce exposure to sideways wind gusts while solid waste is being emptied into the hopper H of the front loading truck F, as will be described. In addition, rotation of the pickup sleeves156about the respective trunnion pins162is limited to prevent over-travel while the dumpster30is being raised and tipped above the hopper H of the front loading truck F, as will be described.

As best shown inFIGS. 30 and 32, at least one mechanical stop170is provided medially on the exterior surface of one of the opposed side walls50of the dumpster30. Preferably, a mechanical stop170is fixed on each side wall50at a predetermined location above the respective pivot160such that the distal ends of the lifting arms A will engage the mechanical stops170when the dumpster30is lifted above the hopper H of the front loading truck F, as illustrated inFIG. 33. As shown, the mechanical stop170comprises a relatively short L-shaped section of a strong, rigid material, such as angle iron, and is preferably coated, painted or galvanized to inhibit corrosion. However, the mechanical stop170may be any known expedient for engaging the lifting arm A of the front loading truck F and thereby reduce the stress exerted on the lifting arm A when the weight of the dumpster30shifts over center. For example, the mechanical stop170may comprise a piston or elastomeric material for absorbing a portion of the stress exerted on the lifting arm A when the weight of the dumpster30shifts over center.

The end wall60adjacent the lifting sleeves156of the dumpster30is configured to contain the refuse within the dumpster30and to direct the refuse into the hopper H of the front loading truck F while the dumpster30is being emptied. As best shown inFIG. 31B, the side walls50are chamfered rearwardly towards the floor40and the top of the dumpster30. The end wall60is formed by a large upwardly opening upper door182having integral side panels183and a relatively smaller downwardly opening lower door184having integral side panels185. The doors,182,184are movable between a fully closed and a fully opened position in a clamshell fashion, and together with the chamfered ends of the side walls50, define a discharge chute that is enclosed on all four sides. In the fully opened position, the side panels183of the upper door182and the side panels185of the lower door184overlap the chamfered ends of the side walls50to reduce the likelihood that a sideways gust of wind will inadvertently disperse solid waste into the environment while the dumpster30is being emptied into the hopper H of the front loading truck F (seeFIG. 33). In addition, the side panels183of the upper door182eliminate air from traveling sideways across the refuse as it is being discharged. As indicated by the phantom lines inFIG. 33, the side walls of the front loading truck F may be extended to substantially eliminate the possibility that refuse will be dispersed into the environment while the dumpster is being emptied. The upwardly opening upper door182hangs between the ends of the side walls50from a lateral hinge181. Upper door182remains closed under the influence of gravity and is biased in the closed position by a linear compression spring186having one end attached to the exterior surface of the upper door182and the other end attached to the top of the dumpster30adjacent top door102at a medial location between the side walls50. Alternatively, hinge181may also be provided with a torsion spring (not shown) for biasing upper door182in the closed position. Similarly, downwardly opening lower door184is biased in the closed position by at least one linear compression spring188having one end attached to the exterior surface of the side panel185of the lower door184and the other end attached to the side wall50at a medial location between the floor40and the top of the dumpster30. As shown, the lower door184is provided with a spring188on each side panel185to insure that the lower door184remains in a closed position until the dumpster30is lifted and tilted by a front loading truck F to be emptied. Furthermore, the lip189of the lower door184is positioned inwardly of the lip187of the upper door182. When the dumpster30is tilted, the lower door184opens automatically under the weight of the solid waste in the interior compartment of the dumpster30and forces the upper door184to open. The upper door182is forced open and over center of the hinge181(FIGS. 31B and 33) so that the spring186retains the upper door182in the fully opened position until the influence of gravity causes the upper door182to close and the spring186to retain the upper door182in the fully closed position. Preferably, when the lower door184is in the fully opened position, the interior surface of the lower door184forms an extension of the floor40of the dumpster30. Thus, the lower door184forms a straight line with the floor40as best shown inFIG. 31Bso that the refuse flows smoothly into the hopper H of the front loading truck F through the discharge chute defined by the upper door182, lower door184and chamfered side walls50. Preferably, at least one stop, such as an extension of the feet44on the underside of the floor, is provided on the dumpster30to prevent the lower door184from opening beyond where a straight line is formed.

As best shown inFIGS. 30 and 32, at least one safety lock190is provided medially on the exterior surface of one of the opposed side walls50of the dumpster30. Preferably, a safety lock190is fixed on each side wall50at a predetermined location rearward of the respective pivot160. As shown, the safety lock190comprises a locking arm192rotatably mounted on a pivot pin194protruding outwardly from the exterior surface of the side wall50. As illustrated inFIG. 33, the locking arm192rotates about the pivot pin194when the dumpster30is lifted and tilted above the hopper H of the front loading truck F. The locking arm192rotates under the influence of gravity so that the locking arm192remains oriented substantially vertical while the dumpster30is lifted and tilted until a protruding lip provided on the locking arm192engages a receiving tab196affixed to the underside of the corresponding lifting sleeve156. Once the lip of the locking arm192and the receiving tab196of the lifting sleeve156are engaged, the dumpster30cannot be lifted or tilted any further. Accordingly, over travel is prevented so that the dumpster30does not tip over the front loading truck F. Preferably, as shown inFIG. 33, the locking arm192engages the receiving tab196and the mechanical stop170engages the distal end of the lifting arm A with the dumpster30in approximately the same location above the hopper H of the front loading truck F. As shown, the locking arm192comprises a generally L-shaped section of a strong, rigid material, such as welded iron, and is preferably coated, painted or galvanized to inhibit corrosion. However, the locking arm192may be any known expedient for engaging the lifting sleeve156of the dumpster30and thereby prevent over travel of the dumpster30relative to the front loading truck F. As a result, the capacity of the dumpster30may be increased.

Utilizing the mechanical stop170, the clamshell discharge chute defined by the upper door172, the lower door174and the chamfered side walls50, and the safety lock190, the front loading truck F is not required to rotate the dumpster30nearly as far to discharge solid waste from the interior compartment of the dumpster30into the hopper H of the front loading truck F (compareFIG. 33andFIG. 29). As a result, the lip177of the upper door172and the lip179of the lower door174are clear of the top of the packer blade PB when the dumpster30is lifted and tilted in the dumping position above the hopper H of the front loading truck F. As indicated by the phantom lines inFIG. 33, the packer blade PB is free to move rearward relative to the front loading truck F and the dumpster30to compact the refuse inside the hopper H. Thus, the packer blade PB may be extended before, during and even after the dumpster30is lifted and tilted.

It is to be understood that the forgoing description and specific embodiments shown herein are merely illustrative of the best mode of the invention and the principals thereof, and that various modifications and additions may be made by those skilled in the art without departing unnecessarily from the spirit and scope of the invention, which is intended to be limited only by the scope of the appended claims.