Dump truck systems and method

A dump truck system comprising a vehicle, a trailer assembly on which is mounted a trailer bed, a hitch assembly for connecting the trailer assembly to the vehicle, and trailer dump assembly for pivoting the trailer bed relative to the trailer about a dump axis. Optionally, the dump truck system may comprise a tilt assembly for tilting the trailer bed relative to the trailer assembly about a tilt axis, where the tilt axis is substantially perpendicular to the dump axis. The trailer assembly optionally comprises a trailer frame assembly, a tube member pivotally connected to the trailer frame assembly, and a suspension assembly arranged between the tube assembly and the trailer frame assembly to resiliently oppose transmission of shocks from the trailer frame assembly to the vehicle. The trailer assembly optionally comprises a trailer frame assembly, a support tube member attached to the trailer frame assembly, a slide tube member that extends through and is supported by the support tube member. In this case, the slide tube member moves relative to the support tube member between a retracted position and an extended position.

TECHNICAL FIELD
 The present invention relates to systems and methods for loading,
 transporting, and dumping bulk materials and, more specifically, to such
 systems and methods adapted to transport bulk materials over roadways and
 load and dump these materials at desired locations.
 BACKGROUND OF THE INVENTION
 During construction products, bulk materials such as dirt, gravel, and the
 like must be removed and deposited at the construction site. For example,
 often dirt must be removed from a site during excavation for a foundation.
 Gravel is then often dumped at the site and compacted to form a stable
 substrate for the foundation.
 Conventionally, dump trucks are used to remove the dirt and deposit the
 gravel at the site. Dump trucks are high capacity vehicles that have a
 truck bed that may be tilted to dump the contents from the bed quickly and
 efficiently. In the example give, a loader would commonly be used to load
 dirt onto the truck during the excavation process. The truck will then
 take the dirt to a dumping location where the excavated dirt is to be
 deposited. The truck will then dump the excavated dirt at the dumping
 location. Gravel will normally be loaded onto the truck by an overhead
 conveyor or hopper. The truck will then take the gravel to the
 construction site and dump the gravel at the desired location.
 To improve efficiency, dump trucks often tow a trailer that supports what
 will be referred to as a trailer bed. The trailer bed allows the truck to
 transport approximately twice the amount of dirt or gravel as a truck
 without a trailer bed. Conventionally, the trailer bed is loaded while on
 the trailer and dumped by transferring the trailer bed to the truck bed
 and then tilting the truck bed as described above.
 The need exists for improved dump truck systems and methods that may be
 easily loaded and unloaded and can carry large loads during each trip.
 The term "bulk material" will be used herein to refer to any material that
 may be loaded onto, transported by, and dumped from a dump truck of the
 kind to which the present invention relates. The term "desired location"
 will be used to refer to the precise point at which material is to be
 deposited, while the term "transfer site" will be used to refer more
 broadly to the general area surrounding the desired location.
 SUMMARY OF THE INVENTION
 A dump truck system comprising a vehicle, a trailer assembly on which is
 mounted a trailer bed, hitch means for connecting the trailer assembly to
 the vehicle, and trailer dump means for pivoting the trailer bed relative
 to the trailer about a dump axis. The trailer dump means allows bulk
 material within the trailer bed to be dumped directly from the trailer
 without transferring the trailer bed to the dump truck bed.
 Optionally, the dump truck system may comprise a tilt assembly for tilting
 the trailer bed relative to the trailer assembly about a tilt axis, where
 the tilt axis is substantially parallel to the dump axis. The tilt
 assembly allows the operator to stabilize the dump truck system prior to
 raising the trailer bed using the trailer dump means.
 The trailer assembly optionally comprises a trailer frame assembly, a tube
 member pivotally connected to the trailer frame assembly, and a suspension
 assembly arranged between the tube means and the trailer frame assembly to
 resiliently oppose transmission of shocks from the trailer frame assembly
 to the vehicle. The suspension assembly helps to absorb shock that would
 otherwise be transmitted to the truck.
 The trailer assembly may optionally comprise a trailer frame assembly, a
 support tube member attached to the trailer frame assembly, a slide tube
 member that extends through and is supported by the support tube member.
 In this case, the slide tube member moves relative to the support tube
 member between a retracted position and an extended position. This
 facilitates transfer of the trailer bed to the truck bed and/or the use of
 the trailer dump assembly.

DETAILED DESCRIPTION OF THE INVENTION
 Referring initially to FIGS. 1-4 of the drawing depicted at 20 therein is a
 dump truck system constructed in accordance with, and embodying, the
 principles of the present invention. These FIGS. 1-4 also depict methods
 of using the system 20 embodying the principles of the present invention.
 The present invention is of particular significance, and that application
 will be described in detail herein. However, many of the features of the
 present invention can be applied to other types of trucks, such as logging
 trucks. The following discussion is thus not intended to limit the scope
 of the invention to only environments in which the invention is used on
 improved dump trucks.
 The exemplary dump truck system 20 employs a dump truck 22 and a trailer
 assembly 24. The dump truck system 22 employs a vehicle portion 26 and a
 truck bed 28. The dump truck 22 is generally conventional and will be
 described herein only to the extent necessary for complete understanding
 of the present invention.
 The vehicle portion 26 comprises a vehicle frame assembly 30 that supports
 the truck bed 28. The truck bed 28 comprises a bed gate assembly 32. The
 bed gate assembly 32 may be moved between a closed position (FIGS. 1 and
 4) and an open position (FIGS. 2 and 3) using a gate actuator assembly 33
 (FIG. 9).
 The trailer assembly 24 comprises a trailer frame assembly 40, a hitch
 assembly 42, a trailer bed 44, a trailer dump assembly 46, and a trailer
 tilt assembly 48.
 The dump truck system 20 may operate in any one of a number of
 configurations depending on the circumstances. In FIG. 1, the dump truck
 system 20 is shown in a transportation and loading configuration. In this
 first configuration, bulk material is loaded into the truck bed 28 and/or
 trailer bed 44. Bulk material in these beds 28 and 44 may be moved from a
 source point to a destination point by operation of the vehicle 26.
 In FIGS. 2 and 3, the dump truck system 20 is shown in a second
 configuration in which the trailer bed 44 is loaded into the truck bed 28,
 after which the trailer assembly 24 is detached from the dump truck 22. A
 conventional winch system (not shown) may be used to transfer the trailer
 bed 44 to the truck bed. The dump truck 22 may then be used to dump
 material from the trailer bed 44 in a conventional manner. This second
 configuration would be primarily used in situations in which use of the
 trailer assembly 24 is not practical.
 Referring now to FIG. 4, depicted therein is a third configuration in which
 the trailer bed 44 is dumped directly from the trailer assembly 24 using
 the trailer dump assembly 46. This third configuration is used in
 situations where the trailer assembly 24 may be maneuvered into position
 at the desired location where the bulk material is to be dumped. If the
 trailer assembly 24 can be maneuvered such that this third configuration
 is possible, the bulk material contained in the trailer bed 44 may be
 dumped more quickly and efficiently than using the second configuration
 described above with reference to FIGS. 2 and 3.
 With the foregoing general understanding of the operation of the dump truck
 system 20 in mind, reference is now made to FIGS. 5-7. FIGS. 5-7 show
 details of operation of the trailer tilt assembly 48.
 In particular, FIGS. 5 and 6 show that the trailer bed 44 defines a bed
 reference plane A and the trailer frame assembly 40 defines a frame
 reference axis B. Under most situations, the trailer bed 44 is in the down
 position shown in FIGS. 1-3 and the bed reference plane A is perpendicular
 to the trailer reference axis B.
 However, FIG. 6 shows that the bed reference plane A can be substantially
 misaligned with a true vertical reference plane C on uneven ground.
 Accordingly, maintaining this perpendicular relationship between the bed
 reference plane A and the trailer reference axis B can cause an unstable
 situation on non-level ground when the trailer bed 44 is in its raised
 position as shown in FIG. 6.
 Referring now to FIG. 7, it can be seen that on uneven ground (the trailer
 reference axis B is not horizontal), the trailer tilt assembly 48 is
 operated until the bed reference plane A is substantially parallel with
 the vertical reference plane C. In this case, the bed reference plane A is
 no longer perpendicular to the trailer reference axis B. The trailer tilt
 assembly 48 thus allows the trailer to be unloaded in a stable fashion on
 uneven ground.
 Referring now to FIG. 8, the trailer tilt assembly 48 will now be described
 in further detail. Identified by reference characters 50 and 52 are first
 and second main frame members of the trailer frame assembly 40. These
 frame members 50 and 52 are rigid beams capable of carrying the load of
 the trailer bed 44 and its contents. Referring for a moment to FIG. 5, it
 can be seen that the main frame members 50 and 52 are supported by wheels
 54 mounted on wheel axials 56 and wheel axials struts 58. The wheel axials
 56 define the trailer reference axis B described above.
 Referring back to FIG. 8, the dump assembly 46 comprises a dump axle 60 is
 mounted by dump bearings 62 and 64 to the main frame members 50 and 52.
 The dump axle 60 defines a dump axis D; the dump bearings 62 and 64 allow
 the dump axle 60 to axially rotate about the dump axis D.
 The exemplary tilt assembly 48 comprises a frame flange 66, a bed flange
 68, and a tilt pin 70. The frame flange 66 is rigidly attached to the dump
 axle 60. The frame flange 66 is connected to a bed flange 68 by a tilt pin
 70. The tilt pin 70 allows the bed flange 68 to rotate about a tilt axis E
 relative to the frame flange 66. The bed flange 68 is in turn rigidly
 connected to first and second bed support members 74 and 76 that support
 the trailer bed 44 and its contents. The trailer bed 44 is thus supported
 on the trailer frame assembly 40 in a manner that lets the trailer bed 44
 move in two axes of rotation; i.e., about the dump axis D and the tilt
 axis E relative to the trailer frame assembly 40.
 The exemplary tilt axis assembly 48 further comprises a tilt actuator
 assembly 80 comprising an actuator housing 82 and an actuator piston 84.
 The actuator assembly 80 is conventional and is hydraulically operated to
 extend and retract the piston 84 relative to the housing 82. The housing
 82 is pivotally connected to the dump axle 60 by a housing pin 86, while
 the actuator piston 84 is pivotally connected to a tilt flange 90 rigidly
 extending from the trailer bed 44. Appropriate application of hydraulic
 fluid to the actuator housing 82 increases and decreases the effective
 length of the tilt actuator assembly 80, which in turn causes the trailer
 be 44 to rotate about the tilt axis E as described above with reference to
 FIGS. 5-7.
 Referring now to FIG. 11, depicted therein is a dump actuator 94 that is
 pivotally connected at one end to the trailer frame assembly 40 and at
 another end to the trailer bed 44. The dump actuator 94 is also
 conventional, and appropriate application of hydraulic fluid thereto
 increases and/or decreases the effective length of the actuator 94 using
 telescoping parts (see FIG. 4). Operation of the dump actuator 94 thus
 allows the trailer be 44 to be rotated about the dump axis D as described
 above with reference to FIGS. 1-4.
 FIG. 11 also depicts bed wheels 96 that are mounted to the trailer bed 44
 by bed wheel axles 98. These bed wheels 96 engage the trailer frame 40 and
 allow the trailer bed 44 to be moved along the trailer frame 40 as
 depicted in FIGS. 2 and 3 above.
 FIG. 11 further depicts exemplary latch assemblies 100 that may be moved
 between an engaged position (solid lines) in which movement of the trailer
 bed 44 towards the front is prevented and a disengaged position (broken
 lines) in which movement of the trailer bed 44 towards the front is
 allowed. In the engaged positions, the latch assemblies engage the bed
 wheel axles, 98.
 Extending upwardly from the trailer frame 40 are bed stops 102 that engage
 the trailer bed 44 to prevent the bed 44 from moving further towards the
 rear when the trailer bed 44 is in a storage/dump position as shown in
 FIGS. 1, 4, and 11.
 Referring now to FIGS. 1-4, the exemplary hitch assembly 42 used by the
 system 20 will now be described in further detail. The hitch assembly 42
 allows the trailer assembly 24 to be attached to and detached from the
 vehicle 26.
 The hitch assembly 42 comprises a support tube 120, a slide tube 122, a
 support collar 124, and a suspension system 126. The support collar 124 is
 rigidly attached to the trailer frame 40; the support collar 24 also
 pivotally suspends the support tube 120 from the trailer frame 40 such
 that the support tube 120 rotates relative to the trailer frame 40 about a
 suspension axis F. The slide tube 122 is slidably supported by the support
 tube 124 such that the slide tube 122 moves between an extended position
 (FIG. 1) and a retracted position (FIGS. 2-4). The suspension system 126
 is mounted between the support tube 120 and the trailer frame 40 to
 resiliently oppose movement of the support tube 120 towards the trailer
 frame 40. A hitch assembly 128 is formed by a tongue assembly 130 and a
 receiver assembly 132. The tongue assembly 130 is rigidly connected to the
 slide tube 120, while the receiver assembly 132 is rigidly connected to
 the vehicle 26. The tongue assembly 130 is adapted to be detachably
 attached to the receiver assembly 132 in a conventional manner. The hitch
 assembly 128 is thus generally conventional and allows the slide tube 122
 to be rigidly connected to and detached from the vehicle 26. A jack
 assembly 133 is rigidly connected to the trailer frame 40 to support the
 trailer assembly 24 when the trailer assembly 24 is detached from the
 vehicle 26.
 Referring now to FIGS. 9 and 10, depicted therein are lock projections 134
 and lock cavities 136 that allow the trailer frame 40 to be directly
 supported by a structural, portion 138 of the vehicle frame assembly 30.
 The lock projections 134 are formed on the main frame members 50 and 52.
 The lock cavities 136 are formed in the structural portion 138 of the
 trailer frame 40. The lock cavities 136 are sized and dimensioned to
 snugly receive the lock projections 134 such that movement of the main
 frame members 50 and 52 up, down, sideways, or towards the vehicle 26 is
 substantially prevented. Optionally, lock pins 140 may be passed through
 lock holes 142 in the lock projections 134 to prevent withdrawal of the
 lock projections 134 from the lock cavities 136 under normal use.
 The lock projections 134 and lock cavities 136 allow the trailer assembly
 24 to be secured to the vehicle assembly 26 during the second and third
 configurations of used shown in FIGS. 2-4.
 Referring now to FIGS. 12 and 13, the optional suspension system 126 will
 now be described in further detail. The suspension system 126 comprises a
 suspension housing 150, a suspension bracket 152, and an air bag system
 154. The suspension housing 150 is rigidly connected to a cross member 156
 that extends between the main frame members 50 and 52 and forms a part of
 the trailer frame assembly 40. Brace members 158 further rigidly connect
 the suspension housing 150 to the trailer frame 40.
 The suspension bracket 152 is rigidly attached to the support tube 120 such
 that the bracket 152 is substantially contained within the suspension
 housing 150 with a bracket surface 160 on the suspension bracket 152
 facing a housing surface 162 on the cross member 156. The air bag system
 154 is contained within the suspension housing 150 between the bracket
 surface 160 and the housing surface 162.
 The air bag system 154 is conventional and, when inflated, resiliently
 opposes movement of the bracket surface 160 towards the housing surface
 162. As described above, the support tube 120 is pivotally connected to
 the trailer frame 40 by the support collar 124. This pivotal connection
 allows the support tube 120 to pivot in the direction shown by arrow G in
 FIG. 13 relative to the trailer frame 40. The air bag system 154 will
 resiliently oppose movement in the direction shown by arrow G.
 Accordingly, in the first configuration shown in FIG. 1, with the slide
 tube 122 in the extended position and the trailer assembly 24 connected to
 the vehicle 26, the suspension system 126 will inhibit transmission of
 shocks from the moving trailer assembly 24 to the vehicle 26. The air bag
 system 154 may be inflated and/or deflated in the second and third
 configurations shown in FIGS. 2-4 as necessary to facilitate connection of
 the tongue assembly 130 to the hitch assembly 128 and/or insertion of the
 lock projections 134 into the lock cavities 136.
 From the foregoing, it should be apparent that the present invention may be
 embodied in forms other than those described above. The scope of the
 present invention should thus be determined by the following claims and
 not the foregoing detailed description.