Fifth-wheel hitch system

A fifth-wheel hitch system is described including: (a) a framework having an upright support; wherein the framework is adapted to be secured to a towing vehicle; (b) a support plate member secured to the top of the support member; wherein the plate member preferably includes a raised central portion and lower side portions; (c) a yoke member attached to the support plate member with fasteners which allow the yoke to be tilted away from the raised central portion of the plate member and then biased back to a central position; and (d) a receiver member attached to the yoke member for receiving and releasably connecting to the king pin of a trailer to be towed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon, and claims priority from, my Provisional Application No. 61/853,269, filed Apr. 1, 2013.

FIELD OF THE INVENTION

This invention relates to hitch systems used for pulling or towing fifth-wheel type trailers with a towing vehicle (e.g. a truck). More particularly, this invention relates to improvements in the construction and utilization of fifth-wheel hitch systems.

BACKGROUND OF THE PRIOR ART

Conventional fifth-wheel hitch systems involve use of a king pin secured to the underside portion of the forward end of a trailer to be towed, e.g. a camper trailer. The truck used for towing the trailer has a receiver portion mounted to it which is adapted to receive and releasably connect to the king pin. Normally the receiver portion is secured to a framework in the bed of the truck with a plurality of bolts which extend downwardly through the bed and are fastened to the truck frame. The receiver portion (a receiver plate) may be attached to the hitch framework by means of a yoke member which allows the receiver plate to tilt or rotate about a horizontal plane which is perpendicular to the longitudinal axis of the truck. This feature allows the receiver plate to tilt forwardly or rearwardly, for example, relative to the hitch framework when the towing truck goes over inclines or sloping terrain where the rear wheels of the truck become raised (or lowered) relative to the front of the truck.

However, in certain towing situations the trailer is subjected to various twisting forces, e.g. when the towing vehicle is tipped to one side or the other relative to the trailer, such as when the towing vehicle turns onto or off from a roadway which is lower or higher than its current path. In those situations one side of the towing vehicle becomes higher that the other side while the trailer is still in the original plane. This twisting action also can occur when only one side of the towing vehicle travels over a bump (or through a hole). These twisting forces are very undesirable. They place further burdens on the hitch system itself, and the trailer frame can be twisted or otherwise damaged.

A prior art method for alleviating the problem of twisting forces in the fifth-wheel hitch involves the use of a universal joint in which there are two axis of rotation at 90° to each other. This necessarily requires maintenance of two joints and also adds to the overall weight and cost of the hitch system.

There has not heretofore been provided a fifth-wheel hitch system having the advantages and features of the present invention.

BRIEF SUMMARY OF THE INVENTION

The present invention provides an improved fifth-wheel hitch system comprising:

(a) a framework system comprising an upright support member; wherein the framework system is adapted to be secured to a towing vehicle;

(b) a support plate secured to the top of the support member; wherein the support plate member preferably includes a raised central portion and lower side portions;

(c) a yoke member attached to the plate member by means of fasteners which allow the yoke member to be tilted away from the central portion of the plate member and then biased back to a central position; and

(d) a receiver portion attached to the yoke member for receiving and releasably connecting to the king pin of a trailer to be towed.

The improved fifth-wheel hitch system enables the receiver portion of the hitch to tilt either to the left or to the right of the longitudinal centerline of the towing vehicle, as needed in order to accommodate left and right tilting of the trailer being towed as the trailer travels over uneven ground. This avoids twisting of the trailer frame. In one embodiment the fifth-wheel hitch system can be easily secured to a conventional ball-type hitch in the bed of a truck. The hitch system of the invention can be easily disconnected from the ball-type hitch when the fifth-wheel hitch is no longer needed.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the hitch system10of the present invention is illustrated inFIG. 1. The hitch system includes an upright support member12having a plate member14secured to its upper end. Attached to the plate member is a yoke16having a relative flat base17and outwardly protruding shafts or fingers18(one extending outwardly from each side of the yoke, as shown). The yoke is attached (by means of fingers18) to the legs32of a receiver30. The receiver includes a pathway34for guiding the king pin42of trailer40to a lockable (i.e. latch) position in the receiver where latch36captures the king pin. Lever37enables the user to unlatch the king pin when desiring to unhook the trailer from the towing vehicle. Because the receiver is attached to the yoke solely by means of the fingers on the sides, the yoke allows for pivoting action of the receiver in the longitudinal direction but not in a side-to-side or lateral direction

The yoke is attached at the center of its base to the central portion of the support plate14by means of bolts20which extend through corresponding holes in the yoke base and the plate14. A spring21encircles the bolt and provides a biasing action when yoke16is tilted to one side or the other away from the center of the support plate. The tension on the spring can be increased (or decreased) by means of tightening or loosening nut22on the upper end of bolt20.

As shown inFIG. 1, the support plate may have a central portion15which is raised relative to the rest of the support plate. This may be by means of a crease in the plate or by means of an arc in the plate. In either event, a gap24is created between each side portion of the plate and the base of the yoke. The gap is preferably at least about 0.5 inch but could larger (e.g. about 1 inch). The gap on each side of the plate enables the yoke16to be tilted either to the right or to the left (e.g. when the trailer or the towing truck go over bumps or holes in the roadway, or when the truck turns off from one road onto another and the roadways are at different elevations). This avoids harmful twisting of the trailer while towing.

FIG. 2is an elevational view (partially cut-away) of another embodiment of hitch system of the invention where the upright support member50is bolted to the frame60below bed62of a towing vehicle by means of bolts52. The support member50includes a plate54to which the yoke member16is attached by means of bolts20. A gap24is shown between the side portions of the support plate54and the yoke member16.

FIG. 3is an elevational view (partially cut-away) showing another embodiment70of hitch system of the invention. In this embodiment the lower end of the upright support member72is releasably connected to a conventional ball80secured in the bed82of a towing vehicle. The connection is made by means of locking pins71which are adapted to move in separate guideways71A between retracted and extended positions to lock the support member to the ball80. The locking pins are located on opposite sides of the ball, as shown. Rotatable cam members (which are pivotably mounted to ears75) are caused to push the locking pins upwardly against the ball by means of threaded screws74. A support plate76is secured to the upper end of the support member72, and yoke16is attached to the support plate by means of bolts20(as described in connection withFIG. 1). A gap24is shown between the side portions of the plate76and the yoke16. The receiver32for the hitch system is attached to the ears18of the yoke, as described in connection withFIG. 1.

The embodiment shown inFIG. 3is especially useful when it is desired to use the existing ball-type hitch in a towing vehicle in order to tow a trailer which has a fifth-wheel type hitch. Thus, it is not necessary to purchase a relatively heavy and expensive framework for a conventional fifth-wheel hitch arrangement. Also, with the embodiment shown inFIG. 3, the upright support member can be easily and quickly detached from the ball hitch so that the towing vehicle can use the ball hitch for towing gooseneck trailers.

FIGS. 4A and 4Bare elevational views illustrating two different manners in which the side portions of the support plate are lower than the central portion of the plate. InFIG. 4Athe support plate14is curved so that the outer portions of the plate form a gap24on each side, as shown. Preferably the gap is in the range of about 0.5 to 1 inch. InFIG. 4Bthe support plate14A includes a central ridge15A (with the ridge extending along the center of the plate in a longitudinal direction of the towing vehicle). Gap24is therefore provided between the outer portions of the support plate and the yoke16. The extent of the crease forming the ridge may vary, but typically a crease of about 5 degrees is sufficient to provide the desired gap on each side. As previously stated, the presence of the gaps on the sides of the plate enable the yoke (and, thus, the trailer) to rock or tilt to one side or the other when the trailer and towing vehicle go over bumps or uneven ground.

FIGS. 5A and 5Billustrate other embodiments of the hitch system wherein the support plate11is planar, and the yoke member has been modified so that a gap25is defined at each side edge between the yoke and the support plate. InFIG. 5Athe yoke32A is provided with a slightly rounded or curved bottom surface, as shown. InFIG. 5Bthe yoke32B has been provided with a creased bottom, as shown, with the crease running in the longitudinal direction.

FIG. 6illustrates one type of bracing which may be used in conjunction with the hitch system which is connected to a conventional ball-type hitch in a towing vehicle. The bracing includes elongated base member100having a central opening101to accommodate the ball80secured in truck bed82. The base member100lies on the bed of the truck and may include elongated leg extension members92positioned on opposite sides of the base member and bolted thereto by means of bolts103, for example. Brace members93are positioned forwardly and rearwardly of the upright support member12. The lower end93A of each brace is secured to the base member100with bolts96which extend through the lower end of the brace and through elongated slots102in the base. The upper ends93B of the braces are positioned, respectively, against the forward and rearward sides of the upright support member12beneath stop members95(which may be, for example, metal bars welded or otherwise secured to the support post12on the forward and rearward surfaces, as shown). Turnbuckles94are attached at opposite ends thereof to the two braces93. When the turnbuckles are tightened, the upper ends93B of braces93are drawn upwardly against stop members95, and the lower ends93A are pulled toward the support post12(sliding the bolts96in the slots102) to complete triangular bracing of the support post. In this manner, the support post is very rigidly held in a straight upright position during use. It is very easy to remove the bracing when it is necessary to remove the hitch system from the truck bed.

Other variants are possible without departing from the scope of this invention.