TOWABLE TRAILER ASSEMBLY

Abstract

A trailer assembly for use with a towing vehicle such as a dump truck. The assembly comprises a pup trailer that has a fixed or a terminally-steerable front axle and an adjustable length tongue that secures the trailer to the towing vehicle. The trailer and tongue are secured to each other by a pivot that has a single lateral axis. The pivot permits vertical pivoting of the trailer and tongue relative to each other through a range of motion that is as much as forty degrees above and below the horizontal. The pivot resists lateral pivoting motion between the tongue and trailer. The assembly permits the trailer to be easily towed over uneven terrain and resists the tendency of the trailer to tip during towing and during dumping.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiments of the invention, illustrative of the best mode in which applicant has contemplated applying the principles, are set forth in the following description and are shown in the drawings and are particularly and distinctly pointed out and set forth in the appended claims.

FIG. 1 is partial side view of a truck and pup trailer incorporating the tongue of the present invention;

FIG. 2 is a top view of the tongue shown at its minimum length;

FIG. 3 is a top view of the tongue shown at an extended length;

FIG. 4 is an enlarged top view of the pivot taken through line 4-4 of FIG. 1; and

FIG. 5 is a partial side view of the truck and pup trailer traveling over uneven terrain.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-5, there is shown a self-supported trailer in accordance with the present invention and generally indicated at 10. For the purposes of this description, it may be advantageous to define a longitudinal direction “11a”, lateral direction “11b” and transverse direction “11c” positioned to be mutually orthogonal. In general, the longitudinal direction 11a will be aligned with the longitudinal axis of trailer 10. The lateral direction 11b will extend substantially at right angles to the longitudinal axis of trailer 10 and the transverse or vertical direction 11c will be aligned with a direction close to vertical. All directions are relative with respect to trailer 10. Trailer 10 is designed to support and transport a payload therein and to dump the same. Trailer 10 is further designed not to overturn during such operations.

Trailer 10 comprises a front wall 13, a pair of opposed side walls 14, a rear dump door 15 and a floor 16 (FIG. 2). Floor 16 may additionally be supported by longitudinally aligned rails (not shown) positioned under floor 16. Front wall 13, side walls 14, dump door 15 and floor 16 define a load carrying bed 17 that is supported by a sub-frame 18. Multiple suspensions (not shown) and wheels 31 mounted on axles 32, in turn, support sub-frame 18. Each pair of wheels 31 is mounted on an axle 32. In the system illustrated in FIGS. 1&5, at least four axles 32 support bed 17. Specifically, the foremost axle 32a is one of a fixed and a terminally-steerable axle. The rearmost axle 32b may also be a terminally-steerable axle.

Although not shown in any detail, trailer 10 also includes a hoist cylinder 22 that is attached to the front end 10a of trailer 10 between sub-frame 18 and bed 17. Bed 17 is connected to sub-frame 18 at a rear end 10b of trailer 10 by a hoist pivot 23. When hoist cylinder 22 is activated, it causes bed 17 to rotate about hoist pivot 23 in the direction indicated by arrow “A” (FIG. 1). This raises bed 17 from a horizontal position to an inclined dumping position thereby allowing a load (not shown) carried on bed 17 to exit trailer 10 through the pivoted dump door 15.

In accordance with a specific feature of the present invention, trailer 10 includes two pairs of spaced apart first flanges 40 that extend forwardly and outwardly from a front end 10a of sub-frame 18. First flanges 40 are positioned at a height that is above the underside 18a (FIG. 1) of sub-frame 18 and proximate side edges 18b, 18c (FIG. 4) thereof. An aperture 42 is defined in each first flange 40 and apertures 42 in the first flanges 40 are aligned one with another. An expandable tongue 12 is used to secure trailer 10 to a towing vehicle 50 such as a dump truck.

In accordance with another specific feature of the present invention and as shown in FIGS. 2 and 3, tongue 12 has two parts, a tongue front 28 and a tongue back 29. Tongue front 28 comprises one or more rails 60 and has a hitch attachment device 21, such as a pintle eye, secured to a first end 28a thereof. Hitch attachment device 21 is designed to be secured to a hitch 52 on vehicle 50. Tongue front 28 has a length “L1” as measured from hitch attachment device 21 to a second end 28b thereof. Tongue back 29 comprises a pair of legs 62 and a base 64. A first end 64a of base 64 includes an aperture (not numbered) through which rails 60 of tongue front 28 are slidably received. Legs 62 extend outwardly and rearwardly from a second end 64b of base 64. Legs 62 diverge away from each other to form a generally V-shaped member when viewed from above. A tapered gap 66 is defined between legs 62a, 62b. A bar 68 extends from an outer edge of leg 62a to an outer edge of leg 62b. A pair of spaced apart second flanges 70 extend rearwardly from bar 68. Each second flange 70 defines an aperture 72 therein. Each aperture 72 is alignable with the apertures 42 in first flanges 40.

In accordance with another specific feature of the present invention, tongue 12 is adjustable in length between a minimum length L2 and a maximum length L3. When tongue 12 is at its minimum length L2, tongue front 28 extends only partially out of first end 64a of base 64. When tongue 12 is to be extended, tongue front 28 is slid outwardly for a distance by sliding tongue front 28 out of the aperture in base 64. When tongue front 28 is slid outwardly to its greatest degree, the length of tongue 12 is at a maximum length L3. Tongue 12 is reduced in length by pushing tongue front 28 inwardly into gap 66. A locking mechanism (not shown) is provided for securing tongue 12 at a desired length.

In accordance with yet another specific feature of the present invention, a pivot rod 20 extends through the aligned apertures 42, 72 in first and second flanges to secure trailer 10 to tongue 12. For purposes of this application, pivot rod 20 comprises one or more coaxial metal bars that extend in a lateral direction 11b across sub-frame 18. The attached figures show a pivot rod 20 that is a single, unitary bar that extends substantially from one side 14a of trailer 10 to the other side 14b thereof. Pivot rod 20 has a single lateral axis and is the only structural connection between tongue 12 and trailer 10. Pivot rod 20 is secured in place by suitable connectors 74. It should be noted that there are no stops or obstructions provided on tongue 12, first flanges 40, second flanges 70, or on sub-frame 18 to prevent significant relative rotation of tongue 12 and trailer 10 pivot rod 20. Tongue 12 and trailer 10 are therefore free to rotate relative to each other about pivot rod 20 through as much as plus or minus forty degrees relative to the horizontal. Tongue 12, because of its unrestricted motion about pivot rod 20 is therefore useful to enable trailer 10 to be moved across more uneven terrain than was possible with previously known pup trailers, without damage being done to trailer 10.

Bed 17 of trailer 10 has a bed-load center, indicated at 24 (FIG. 1), that is positioned forward of the rearmost suspension associated with rearmost wheel 31a. Overturning of trailer 10 can occur if the load center 26 of the trailer and load shifts to behind the rearmost suspension. This is most likely to occur during dumping, particularly if the dump door 15 remains closed. Tongue 12 and trailer 10 of the present invention are connected together and axles placed in such a manner that the bed load center 24 is always in a position that is forward of the rearmost axle. Furthermore, the load center 26 always remains forward of the rearmost axle on the trailer, even during dumping on a 10% grade.

FIG. 5 shows vehicle 50 on a substantially horizontal surface 80 and trailer 10 on a severely inclined surface 82. As there are no stops or obstacles to restrict the pivotal motion between tongue 12 and trailer 10, wheels 31b remain in contact with surface 82. Bed-load center 24 is far enough forward of the rearmost suspension associated with wheels 31a to prevent overturn of trailer 10 due to load center 26 being behind the rearmost suspension.

In use, tongue 12 is connected to vehicle 50 by securing hitch attachment device 21 on tongue 12 to hitch 52 on vehicle 50. The driver determines what length of tongue 12 needs to be provided between axle 54 on vehicle 50 and axle 32a (FIG. 5) on trailer 10. If it is decided that a longer tongue 12 is required, the brakes (not shown) on trailer 10 are applied, and the driver drives vehicle 50 forwardly away from trailer 10 so that tongue front 28 slides outwardly away from base 64 of tongue back 29. When the appropriate length of tongue 12, such as length L3 is reached, tongue front 28 is locked into position by engaging the provided locking mechanism (not shown). The brakes are disengaged and vehicle 50 may then be driven over surface 80 pulling trailer 10 behind it.

If the load (not shown) in trailer 10 is to be dumped down a steeply inclined surface, such as 82, vehicle 50 is reversed so that trailer 10 rests on inclined surface 82 and vehicle 50 remains on horizontal surface 80. As trailer 10 transitions the ridge 84 between surfaces 80 and 82, sub-frame 18 pivots vertically about pivot rod 20.

The device of the present invention does not include any physical stops or limiting devices that are operationally connected to the tongue 12 or trailer 10 and that would limit the pivotal motion between the tongue 12 and trailer 10 during normal operation. During normal operating conditions, the tongue 12 and trailer 10 can pivot relative to each other through a range of motion between about forty degrees above the horizontal to about forty degrees below the horizontal, without encountering any obstructions to that pivotal movement by components on either of the tongue or trailer.

As there are no structural stops or obstacles on tongue 12 or trailer 10 that will restrict the pivotal motion between the trailer's sub-frame 18 and tongue 29 during normal operating conditions, the wheels 31 on trailer 10 tend to remain in contact with surface 80, ridge 84 and surface 82 at all times when vehicle 50 is at one orientation from level and the trailer 10 at another. When vehicle 50 has been reversed to the point that the appropriate dumping zone is reached, hoist cylinder 22 is activated so that front end 10a of trailer 10 is raised as bed 17 pivots about hoist pivot 23. The load slides outwardly from bed 17 through dump door 15. Once the load has exited bed 17, hoist cylinder 22 is activated to lower bed 17 back toward sub-frame 18. Vehicle 50 is driven forwardly so that trailer 10 is pulled back over lip 84 and onto surface 82. As front end 10a of trailer 10 passes over lip 84, sub-frame 18 thereof pivots about pivot rod 20. This permits trailer 10 to be pulled over a ridge without inducing a bending moment into tongue 12 of trailer 10.

If at some stage it is decided that tongue 12 is too long, then the brakes on trailer 10 are locked, the locking mechanism on tongue 12 is disengaged and the driver reverses vehicle 50 back toward trailer 10. Tongue front 28 is slid rearwardly into base 64. When tongue 12 is at the appropriate length, then the locking mechanism is engaged. The brakes on trailer 10 are released and vehicle 50 can then be used to tow trailer 10.

The present invention has been tested in the field by causing a towed pup trailer to be reversed from a horizontal surface and over an incline of about twenty degrees while the towing vehicle remained on the horizontal. When the pup trailer was on the incline and the vehicle was on the horizontal surface, the trailer was activated to dump its load. After dumping, the trailer was lowered and driven forwardly back onto the horizontal. During this entire procedure, the trailer did not tip over or even begin to tip over. Furthermore, with the vehicle on the horizontal surface and the trailer on the twenty degree incline, all the wheels on both the towing vehicle and the pup trailer remained in constant contact with the ground.

In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover, the description and illustration of the invention are an example and the invention is not limited to the exact details shown or described.

Claims

1. A trailer assembly comprising: a trailer having a load-carrying bed and a plurality of pairs of wheels, each pair of wheels being mounted on an axle; wherein said bed has a front end and a back end and a longitudinal axis extending therebetween; and wherein at least a first axle proximate the front end of the trailer is one of a fixed and a terminally-steerable axle;a tongue that is adjustable in length between a maximum length and a minimum length; and wherein said tongue has a first end and a second end; and a longitudinal axis between said first and second end; anda pivot which secures the front end of the trailer to the second end of the tongue; said pivot being oriented substantially at right angles to the longitudinal axes of the trailer bed and tongue; whereby said tongue and trailer are able to pivot vertically about said pivot.

2. The trailer assembly as defined in claim 1, wherein said trailer bed comprises a front wall, a back wall, a pair of side walls and a floor that surround and define a cavity adapted to receive the load; and wherein said pivot is formed with a single rod.

3. The trailer assembly as defined in claim 1, further comprising at least one pair of first flanges extending outwardly and forwardly away from the front end of the trailer; a pair of spaced apart second flanges extending outwardly and rearwardly from the second end of the tongue; wherein each of said first and second flanges define an aperture therein; and wherein said apertures are alignable with each other; anda pivot rod extends through said aligned apertures to form the pivot.

4. The trailer assembly as defined in claim 3, further comprising a second pair of first flanges extending outwardly away from the front end of the trailer.

5. The trailer assembly as defined in claim 4, wherein each second flange is received between the flanges of one of the pairs of first flanges.

6. The trailer assembly as defined in claim 1, wherein said trailer further comprises a sub-frame which supports the load-carrying bed thereon; and wherein said pairs of first flanges extend outwardly and forwardly away from said sub-frame.

7. The trailer assembly as defined in claim 6, wherein the pairs of first flanges extend outwardly from a front end of the sub-frame; and one of the pairs of first flanges is proximate a first longitudinal side edge of the sub-frame; and the other of the pairs of first flanges is disposed proximate a second longitudinal side edge of the sub-frame.

8. The trailer assembly as defined in claim 7, wherein the pairs of first and second flanges are further positioned vertically above an underside surface of the sub-frame.

9. The trailer assembly as defined in claim 1, wherein said tongue comprises: a tongue front having a first end and a second end, anda tongue back having a first end and a second end; said first end of said tongue back being configured to adjustably engage the second end of the tongue front.

10. The trailer assembly as defined in claim 9, wherein the tongue front further includes a hitch attachment device secured to the first end of the tongue front; said hitch attachment device being adapted to be secured to a hitch on a towing vehicle.

11. The trailer assembly as defined in claim 9, wherein said tongue back includes an aperture in said first end; and wherein said second end of the tongue front is slidably receivable through said aperture; and wherein said tongue front is slid in a first direction to increase the length of the tongue and said tongue front is slid in a second direction to decrease the length of the tongue.

12. The trailer assembly as defined in claim 11, wherein said tongue back comprises: a base in which the aperture is defined;a bar;a pair of legs extending between said base and said bar; anda gap defined between said legs; said gap being sized to receive the second end of the tongue front therein.

13. The trailer assembly as defined in claim 12, wherein said legs originate in said base and diverge away from each other; and wherein said gap increases in width from proximate the base to proximate the bar.

14. The trailer assembly as defined in claim 13, further comprising at least one pair first flanges extending outwardly and forwardly away from the front end of the trailer; and a pair of spaced apart second flanges extending outwardly and rearwardly from the bar on the tongue back; wherein each of said first and second flanges define an aperture therein; and wherein said apertures are alignable with each other and the pivot rod extends through said aligned apertures.

15. The trailer assembly as defined in claim 1, wherein the trailer includes four or more axles and four or pairs of wheels associated therewith.

16. The trailer assembly as defined in claim 1, wherein the trailer further comprises; a sub-frame disposed beneath the load-carrying bed;a hoist pivot securing the back end of the bed to the sub-frame;a hoist cylinder operationally engaged with the front end of the bed and being activatable to selectively raise and lower the front end of the bed with respect to the sub-frame.

17. The trailer assembly as defined in claim 16, wherein the bed further comprises a pivotally mounted dump door at the back end thereof; said dump door being pivoted into an open position when the hoist cylinder is activated to raise the front end of the bed away from the sub-frame.

18. The trailer assembly as defined in claim 1, wherein the pivot rod is substantially parallel to the foremost axle and the trailer is pivotable about an axis that is parallel to the foremost axle, whereby the trailer is able to follow the towing vehicle over uneven terrain without placing bending moments on the tongue.

19. The trailer assembly as defined in claim 1, wherein the adjustable tongue and trailer are able to pivot to around forty degrees above and below the horizontal.

20. The trailer assembly as defined in claim 1, wherein the bed of the trailer has a load center and said load center shifts between a foremost position when the bed is in a towing orientation and a rearmost position when the bed is in a dumping orientation; and wherein the load center remains forward of the rearmost axle on the trailer when the bed is both the towing and the dumping orientations.

21. A trailer assembly comprising: a trailer having a load-carrying bed and a plurality of pairs of wheels, each pair of wheels being mounted on an axle; and wherein at least a first axle proximate a front end of the trailer is a terminally-steerable axle;an adjustable length tongue that is adapted to be secured to a towing vehicle at a first end; anda pivot; wherein said pivot has a single lateral axis and wherein the only structural connection between said trailer and a second end of said tongue is the pivot.