Abstract:
An attachment, primarily for a tractor having a three point hitch, has a post with a seat for a gooseneck hitch ball, and mounting brackets for a fifth wheel type hitch that permit a limited amount of pitch and roll.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     None. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     This invention relates generally to towing attachments mounted on vehicles. It is especially well adapted to be employed with a tractor with a three point hitch, alternatively to provide a fifth wheel hitch or a gooseneck hitch. It has particular, but not exclusive, application to a Category 3 tractor. 
     A wide array of loads, and many configurations and styles of load carriers, such as trailers and flat-beds are pulled by tractors with a three point hitch. Such tractors have the capacity to pull many loads over rough terrain, but are not intended to pull such heavy loads as a heavily loaded trailer such as the type pulled over the road by eighteen wheelers, but for pulling fifth wheel trailers such as farmers use on small type trucks. A three point hitch comprises two hydraulically operated arms spaced horizontally from one another in one plane, extending from the rear of the tractor, and a third pivoted arm, generally equidistant from the two arms and above the plane of the two arms; also extending from the rear of the tractor and oriented so that the three arms form three points of a triangle. In the device described, the third arm is threaded at one end and connected at that end by a yoke to the tractor and by a pintle at the other end to the attachment of this invention. Making the third arm manually adjustable is conventional, and forms no part of this invention. conventionally the three point hitch is attached directly or through a frame connected to the three arms, to a load carrier that is to be pulled by the tractor. 
     There are many occasions when it is desired to move a load carrier equipped with a gooseneck or a fifth wheel hitch receiver. A gooseneck hitch is a hitch in which a ball is received in a socket carried by the load carrier, the load carrier&#39;s weight then being counterbalanced by the hitch and its own contact with the ground. 
     A fifth wheel hitch has on the load carrier a downwardly depending post, often with a spherical terminus, extending from a flat bearing surface. The prime mover has a plate with a hole in it to receive the post, the plate serving as a load bearing surface complementary to that of the load carrier. In the fifth wheel hitch, the hole into which the post extends usually takes the form of a notch in the rearwardly facing edge of the prime mover plate, and jaws, defining between them the “hole”, which are opened when the post is put into position, and closed and locked in position after the post has been properly positioned. The plate&#39;s generally smooth surface faces upwards, and the rearward portion is angled downward to provide a ramp. The bearing surface of the load carrier rests against this plate, which is well greased. 
     As recited in U.S. Pat. No. 4,340,240, normally a tractor three point hitch is capable of engagement with but one arrangement of implement attachment points, and none has been adapted to handle both a gooseneck and a fifth wheel type of the kind described above. The gooseneck and fifth wheel types are often associated with quite different vehicles. For instance, it is common for a flat-bed pickup truck to have a gooseneck attachment directly over the rear differential of the truck. It is common for a semi-trailer rig to incorporate a fifth wheel hitch. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a tractor attachment connected to a standard three point hitch which is adapted to provide a hitch for load carriers heretofore considered not compatible with a three point hitch. The attachment may readily manually be converted to a gooseneck hitch, or to a fifth-wheel hitch. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     In the drawings, 
     FIG. 1 is a fragmentary, exploded perspective view of a body of one embodiment of attachment of the present invention and a three point hitch; 
     FIG. 2 is a view in front elevation of a completely assembled attachment serving as a fifth wheel hitch; 
     FIG. 3 is a view in side elevation of the attachment of FIG. 2; 
     FIG. 4 is an exploded view in front elevation of the attachment of FIG. 2; 
     FIG. 5 is a view in perspective of a post bracket of the attachment of FIG. 2; 
     FIG. 6 is a top plan view of the body of FIG. 1, without pins; 
     FIG. 7 is a top plan view of the post bracket of FIG. 5; 
     FIG. 8 is a view in perspective of a fifth wheel mount bracket of the first embodiment of FIG. 2; 
     FIG. 9 is a view in perspective of a fifth wheel mount portion of the attachment of FIG. 2; 
     FIG. 10 is a top plan view of the fifth wheel mount of FIG. 9; 
     FIG. 11A is a bottom plan view of the fifth wheel mount of FIG. 9, with a jaw mechanism in a closed position; 
     FIG. 11B is a view corresponding to FIG. 11A showing the jaw mechanism in an open position; 
     FIG. 12A is a view in side elevation of one jaw arm of the fifth wheel mount of FIG. 9; 
     FIG. 12B is a view in side elevation of a second jaw arm of the fifth wheel mount of FIG. 9; 
     FIG. 13 is a view in rear elevation of the fifth wheel mount of FIG. 9; and 
     FIG. 14 is an exploded view in front elevation of the attachment of the present invention serving as a gooseneck hitch. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description illustrates the invention by way of example and not by way of limitation. 
     Referring to FIG. 1, reference numeral  10  indicates one illustrative embodiment of a frame of the attachment of the present invention. The frame  10  is mounted to a three point hitch  1 . The three point hitch  1  includes two arms  2  and  3  of a fixed length, with means, not here shown, for raising and lowering them, such means, usually hydraulic, being conventional, and a third arm  4 , the length of which is adjustable. The three arms  2 ,  3 , and  4  form the three points of a triangle. 
     The frame  10  includes a center post  12 , and bottom plate  14  with a flat upper surface  15 . The center post  12  is a square, hollow post, welded at a lower end to the upper surface  15  of the bottom plate  14 . The post  12  has a front wall  5 , a rear wall  6 , side walls  7 , and a heavy top wall  11  welded into an upper end of the post. The bottom plate  14  has two flanges  16 , perpendicular to the surface  13  of the plate, one on each end of the bottom plate  14 . Each of the flanges  16  has a passage through it of a size to admit a threaded shank of a hitch pin  17 . The shank is reduced in diameter with respect to the rest of the pin  17 , to provide a shoulder that bears on the outside surface of the flange when a nut  18 , threaded on the shank, is tightened against the inside surface of the flange, as shown in FIG.  1 . The pins  17  are mounted in holes  19  in the arms  2  and  3  of the three point hitch. The third arm  4  is hingedly mounted to the post  12  between ears  13  welded to the rear surface  6  of the post, as indicated in FIG. 1, by means of a pintle pin extending through a passage in an end of the arm  4  and aligned holes in the ears  13 . 
     The frame  10  further includes two gusset plates  20 . The plates  20  are generally triangular, and each plate  20  is welded to a side wall  7  of the center post  12  and to the upper surface  15  of the bottom plate  14 , for structural support. 
     The top wall  11  of the post has a central seat in the form of a hole  24  in it to receive a gooseneck ball mount  130 . The front wall of the post has a window  9  cut in it to facilitate the installation and securement of the mount  130 . The side walls  7  have aligned passages to receive a mounting pin  21  for use with the fifth wheel adaptor. The mounting pin  21  has a flange at one end. 
     Referring now to FIG. 14, the attachment of this invention is shown as providing for a gooseneck hitch. The gooseneck adaptor  130  has a ball  131  on a neck  132 , and a threaded shank  133 . As the gooseneck adaptor  130  is inserted into the seat  24 , the shank  133  is visible through the window  9 . A lock washer  135  is mounted around the shank through the window  9 , and a nut  136  is inserted through the window  132  and threaded onto the shank  133  to secure the adaptor  130  in the seat  24 . 
     Referring now to FIGS. 2 through 13, for the adaptation of the attachment to a fifth wheel hitch, the center post  12  receives over and around its top end a post bracket  32 . The post bracket  32  has a central sleeve  33 , with a hollow lower portion  34  that is square and fits closely over the upper end of the center post  12 , and a tapered upper portion  35  defined by two spaced parallel walls  36 , integral with front and rear walls of the lower portion  34 . Aligned passages  37  extend through the upper portion  35 . Saddles  38  are welded to an inner face of both of the walls  36  below the passages  37 , to serve as convenient locators for a wheel mount bracket, as will be explained hereinafter. The rear wall of the lower portion of the post bracket is cut away to accommodate the ears  13  on the post  12 , which ears can function as locating stops. The post bracket  32  is secured to the center post  12  with the pin  21 , extending through holes in side walls of the lower portion  34  perpendicular to the walls  36 , and through aligned holes in side walls of the post  12 . 
     The post bracket  32  includes two laterally extending arms  40 , welded to the side walls of the lower portion  34 . Each of the laterally extending arms (see FIG. 5) has, at its outer end two, upwardly extending, divergent tongues  41 , which flare outwardly, upwardly. The tongues  41  are spaced from one another at their lower ends by the width of the arms  40 . 
     A fifth wheel mount bracket  50  (see also FIG. 8) includes a center cylindrical-bearing  52 , aligned with the passages  37  in the post bracket, through which a heavy pivot pin  44  passes. The pin  44  has a flange at one end with a hole through it. A threaded hole in the part  34  immediately below the flange of the pin  44  when it is installed, receives a threaded bolt, which passes through the hole in the flange, and holds the pin  44  in place. The bearing  52  is welded on its top to a lower flat surface of a center plate  54 . The mount bracket  50  also includes a reinforcing beam  55  welded to and structurally securing the bearing  52  and the center plate  54 , as shown particularly in FIG.  4 . The center plate  54  is elongatedly rectangular and includes at its two ends flanges  56 , perpendicular to an upper and the lower flat surface of the center plate. Each flange has in it a bore  58  to receive a pivot pin  60 . The bores  58  are aligned. 
     The pivot pins  60 , extending through the holes  58  in the bracket flanges  56  and corresponding holes  79  in end walls  76 , pivotally secure a fifth wheel mount  70  (see FIG. 9) to the mount bracket  50 , as shown in FIGS. 2 and 4. The fifth wheel mount includes a body  72  with front and rear side walls  73  and  74 , a top wall  75 , the end walls  76 , and a bottom wall  78  (see FIG.  11 A). The bottom wall  78  is recessed somewhat from the front, rear and end walls. A plate  80  is welded to the top wall  75 . The plate  80  has a pair of ramp surfaces  81 , sloping downwardly from the plane of the rest of the plate, and a U-shaped opening  83  in it, long sides of which define edges of the U-shaped opening. Supporting walls  85 , extending between an apron  87  welded to the body and projecting forwardly of the body, and undersurfaces of the ramp surfaces  81 . A post of a fifth wheel trailer passes through opening  83  at the bottom of the U. The plate  80  is smooth, and the ramps  81  allow the fifth wheel trailer to mate easily with the fifth wheel mount  70 . 
     Two flat plate jaws  90 , symmetrically arranged about the U-shaped opening, are pivotally mounted on the bottom plate  78 . As shown particularly in FIGS. 11A and 11B, the jaws  90  have facing semicircular openings  91  in them to receive a necked part of a post depending from a bearing plate of a load carrier fifth wheel mechanism. Sloped edges  92  on the rear part of the plate jaws, where they are pivoted, help guide the neck of the post into the openings  91 . The jaws are moved toward and away from one another by links  93  and  94 , actuated by a lever  95 . The lever  95  has a hole  99  in it. A tab  97 , welded to the side plate  74 , has a hole  98  in it positioned complementarily to the hole  99  in the lever  95 , to receive a holding pin to ensure that the jaws remain closed around the neck of the load carrier post. Such arrangements are conventional. The rear wall  74  of the fifth wheel mount (see FIG. 13) has a slot  120  positioned in the margin of the wall  74  below the bottom wall  78 , through which the lever  95  extends. 
     In assembling the fifth wheel hitch attachment, the post bracket  32  is merely slipped over the top of the post  12 , and pinned to the post with the pin  21 . The fifth wheel mounting bracket is then positioned with the bearing  52  between the walls  36 , and permitted to move down until the bearing, guided by the saddles  38 , rests on the saddles, centered with respect to the holes  37 , and the heavy pin  44  is pushed through the larger of the holes  37  and the other end is threaded into the complementarily threaded hole  37  until a head on the pin engages a flat surface surrounding the hole. In this condition, the bar  55  is positioned between the ears  41 . The fifth wheel mount  70  is positioned between the flanges  56 , with the holes  58  and  79  aligned, and the pins  60  inserted. All or part of the assembly, from the bracket  32  on up, can be pre-assembled. 
     In order to move a load carrier over rough or uneven terrain, the tractor must not be rigidly connected to the fifth wheel. This is accomplished by the use of the attachment of this invention. In use, the fifth wheel hitch is free, within limits, to pitch, roll and yaw. The amount of roll permitted is determined by the configuration of the bar  55  and depth of the ears  41 . The amount of pitch is determined by the clearance between the body  72  and the surface  54  of the bracket  50 . The amount of yaw is determined by the characteristics of the load carrier, the tractor and load carrier being necessarily articulated if the tractor is to steer the load carrier. 
     Merely by way of illustration, the center post  12  can be made of ¼″ steel, four inches by four inches on a side, and any desired height, such, for example, as 21″. The top wall  11  can be 1″ thick and the bottom plate  14 , 1″ thick, 4″ wide and 26″ long. The walls  36  of the post bracket can be ¾″ thick. The bearing  52  can take the form of a pipe, 2½″ o.d., 2″ i.d., and the pivot pin  44 , 2″ o.d. (with just enough clearance in the bearing for a close but sliding fit), drilled axially to its longitudinal center to accommodate a grease fitting at one end, and radially to provide an outlet for grease at the center of the bearing. The dimensions of the other elements of the attachment are consistent with the foregoing. The actual dimensions form no part of this invention, but the foregoing provide some idea of the magnitude of the elements of one embodiment of the attachment. 
     Numerous variations in the construction of the attachment, within the scope of the claims, will occur to those skilled in the art in the light of the foregoing disclosure. Merely by way of illustration, the post  12  can be of any desired cross-sectional configuration, but preferably non-circular so as to provide positive restraint against rotation of the post bracket on the post. The tongues  41  can be differently formed, as long as they receive the bar  55  and limit the amount of roll permitted the load carrier. The attachment can be mounted on the three point hitch in other ways. For example, the arms  2  and  3  may have hook-like appendages instead of the holes  19 , and the pins  17  may then have to be modified, as by having a wide flange at their outer end or a bale to accommodate the hook. The saddles  38  can be eliminated, but their provision makes for easy assembly. The gooseneck ball may be supported by a tapered shaft, seated in a complementarily shaped socket in the top of the post  12 , with a pin or heavy clip to ensure that it does not come out, although in use, the weight of the load carrier will hold it in place. Various additional reinforcing members, in the form of gussets or channels, for example, may be employed. If the post bracket is properly configured, it can contain the gooseneck ball, so that the gooseneck ball can be fixedly secured in the top of the post  12  and the post bracket removably mounted around it. Although as has been indicated, the attachment of this invention has particular utility with tractors with three point hitches, and especially with Category 3 tractors, the attachment can be used with other tractors or other vehicles. In some cases it is desirable to attach front tractor weights to counterbalance the weight of the load carried, depending on tractor size and trailer size. These variations are merely illustrative.