Abstract:
Various embodiments of the present invention comprise apparatus, assemblies and methods for towing a vehicle using a swivel head assembly. The swivel head assembly can permit a grid head of a towing system to roll as well as yaw with respect to a tow arm. Spring members are also provided that can help dampen roll motions.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims the benefit of U.S. provisional patent application Ser. No. 61/305,096, filed Feb. 16, 2010, which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to a swivel assembly for use in towing vehicles. 
         [0004]    2. Description of Related Art 
         [0005]    In the field of vehicle towing, substantial forces are exerted against towing systems that connect a towing vehicle to a towed vehicle. These forces can damage or “wear-down” equipment. It is thus desirable to reduce stress on the equipment. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    In some embodiments of the present invention, a swivel head assembly is provided that allows a grid head used to attach the vehicle being towed to a towing arm to have rotation in two degrees of freedom. The grid head can swivel left or right when the towing vehicle makes a turn (yawing), and it can roll up to 30 degrees from horizontal when the towed vehicle has a roll angle with respect to the towing vehicle. Furthermore, the present invention dampens the motion associated with roll of the towed vehicle, which can help reduce vibration in the towing system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of an embodiment of the swivel head assembly of the present invention, also including a partial perspective view of an end portion of a towing arm. 
           [0008]      FIG. 2  is a perspective view of a towing arm including the swivel head assembly of  FIG. 1  attached thereto. 
           [0009]      FIG. 3  is a perspective view of the swivel head and shaft of the swivel head assembly of  FIG. 1 , without showing a cassette of the swivel head assembly. 
           [0010]      FIG. 4  is an exploded perspective view of the swivel head assembly of  FIG. 1 . 
           [0011]      FIG. 5  is a side elevation view of the swivel head assembly of  FIG. 1 . 
           [0012]      FIG. 6A  is a top plan view of the swivel head assembly of  FIG. 1 . 
           [0013]      FIG. 6B  is a cross sectional view of the swivel head shown in  FIG. 6A , along line  6 B- 6 B. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0014]    In the following description, certain specific details are set forth in order to provide a thorough understanding of various embodiments of the invention. However, upon reviewing this disclosure, one skilled in the art will understand that the invention may be practiced without many of these details. In other instances, some well-known materials of construction, structures and methods of use and manufacture associated with towing arms, towing vehicles, and their related components, have not been described in detail to avoid unnecessarily obscuring the descriptions of the embodiments of the invention. 
         [0015]      FIG. 1  illustrates an embodiment of a swivel head assembly  1  of the present invention, having a swivel head  3  with a shaft  4  (See, e.g.,  FIG. 3 ) encased within a cassette assembly  22 . 
         [0016]    As best seen in  FIGS. 1 &amp; 2 , the swivel head assembly  1  can be connected to a towing arm  50 , by insertion of the cassette assembly  22 , or a portion thereof, into a chamber  51  of the towing arm  50 , and securing the cassette assembly  22  to the towing arm  50  by, for example, without limitation, bolting or screwing the cassette assembly  22  to the towing arm  50 . Both the cassette assembly  22  and towing arm  50  can have a generally rectangular lateral cross section, with the cassette assembly  22  being configured to fit within walls of the towing arm  50 , to be attachable therein. As will be appreciated by those skilled in the art upon reviewing this disclosure, the towing arm  50  can be mounted on a towing vehicle by a mounting system  53 , so that the towing arm  50  and swivel head assembly  1  may extend from the back of the towing vehicle. 
         [0017]    Also, as can be seen in  FIG. 2 , the swivel head  3  of the swivel head assembly  1  can be coupled to a grid head  2 . The grid head  2  can be, in turn, connected to wheel cradles (not illustrated) or other attachment or retaining devices for coupling the towing vehicle (not illustrated) to a towed vehicle, as will be appreciated by those skilled in the art after reviewing this disclosure. 
         [0018]    Referring to  FIGS. 1 ,  6 A &amp;  6 B, in some embodiments, the swivel head  3  contains two generally annularly shaped cavities  15 , the cavities  15  being oppositely facing and including a top circular cavity  15  facing upward and a bottom circular cavity  15  facing downward. Furthermore, a hole  6  is provided through a wall between the cavities  15 . The hole  6  can be concentrically located within the circular cavities  15 . A rod  15 ′ (See, e.g.,  FIG. 2 ) can pass through the hole  6  to attach a grid head  2  to the swivel head  3 . Bearings (not illustrated) can be included in the circular cavities  15  to help guide the rod  15 ′. Referring to  FIG. 2 , the grid head  2  can rotate, or pivot, about a vertical axis “A” of the rod  15 ′, in either direction, as roughly represented by the arrows “B,” thus providing a yaw feature to allow the grid head  2  to pivot in a horizontal plane as the towing vehicle turns. 
         [0019]    As illustrated in  FIGS. 3 &amp; 4 , the swivel head assembly  1  further includes a shaft  4  extending away from the swivel head  1 . One end portion of shaft  4  is attached to the swivel head  3 , while an opposite end portion of the shaft  4  includes a threaded connector  7 . The threaded connector  7  can have a smaller radius than the shaft  4 . Near the threaded connector  7 , on the shaft  4 , an aperture  4 ′can be provided through the shaft  4  for receiving a pin  8 . The pin  8  can be inserted through the aperture  4 ′ such that end portions of the pin  8 , protrude or extend outward on either side of the shaft  4  approximately equal distances from the shaft  4  (See, e.g.,  FIG. 3 ). 
         [0020]    As best seen in  FIG. 4 , the cassette assembly  22  comprises a cassette base  21  having walls that form a generally rectangular cross, with a cavity contained therein defined by its walls. The sides of the cassette assembly  22  include side plates  9 ,  10 , attachable to the cassette base  21 . End plates  11 ,  12  can also be provided, the first end plate  11  having an aperture configured to receive the shaft  4 , to allow the first end plate to slide over the shaft  4  until it abuts against a portion of the swivel head  3 , and the second end plate  12  having an aperture configured to receive the threaded connector  7 , to allow the second end plate to slide over the threaded connecter  7  until an end portion of the threaded connector  7  extends outwardly past the second end plate  12 . A tubular bearing  16  can fit over the shaft  4  such that the shaft  4  is at least partially concentrically located within the bearing  16 , and the bearing  16  can be, in turn, concentrically disposed within a circular tube  15 . Both the bearing  16  and circular tube  15  are shorter in length than the shaft  4  such that they can avoid obstructing the aperture  4 ′ of the shaft  4 . Pairs of end brackets  13 ,  14  can be provided, one pair disposed at each end of the cassette base  21 . Each of the pairs of end brackets  13 ,  14  can be configured such that they can be mated together to provide circular openings to receive and retain the cylindrical tube  15 . The end brackets  13 ,  14  can be located inside the cassette base  21  and may be welded in place. In some embodiments, all of the components of the cassette assembly  22  are retained between the end plates  11 ,  12 , except end nuts (or other end retaining members)  19 ,  20 , which can be securely attached to the threaded connector  7  to securely retain the end plate  12  against the rest of the cassette assembly  22 , placing pressure on the cassette assembly  22  between the end plates  11 ,  12 . 
         [0021]    As further illustrated in  FIGS. 4 &amp; 5 , the cassette base  21 , the side plates  9 ,  10  together with the end plates  11 ,  12 , define windows  23  on each side of the cassette assembly  22 , though which opposite ends of pin  8  can extend and thus move. That is, for example, the cassette base  21  contains a cutaway window portion  23 ′ on each side thereof, on each of its vertical walls. Also, the side plates  9 ,  10  each have an edge cutaway window portion  23 ″, which can be aligned with corresponding cutaway window portions  23 ′ on the cassette base  21 . 
         [0022]    As best seen in  FIGS. 4 &amp; 5 , spring members (or bumpers)  17 ,  18 , are provided to mate with the end portions of the pin  8 . That is, for example, an upper spring member  17  can have a centrally positioned bottom facing semi-circular concave curvature  17 ′ to fit snuggly over a top portion of the shaft  4  and can have one bottom facing semi-circle concave curvature  17 ″ formed on each of two side portions thereof to fit snugly over the top of end portions of the pin  8  (which extend laterally outward past the shaft  4 ). A high-point axis of the centrally positioned semi-circular curvature can be perpendicular to high-point axes of the semi-circular curvatures on the two side portions. Similarly, lower spring member  18  can have a centrally positioned upper facing semi-circular concave surface  18 ′ to fit snuggly over a bottom portion of the shaft  4  in a longitudinal direction, and can have one upper facing semi-circle concave surface  18 ″ formed on each of two side portions thereof to fit snugly over downwardly facing end portions of the pin  8  (which extend laterally outward past the shaft  4 ). A low-point axis of the centrally positioned semi-circular curvature can be perpendicular to low-point axes of the semi-circular curvatures on the two side portions. When the spring members  17 ,  18  are aligned and mated around the shaft  4  and pin  8 , as shown in  FIG. 5 , the end portions of the pin  8  can be held snuggly between the spring members  17 ,  18 . 
         [0023]    The spring members  17 ,  18  may be made from different materials and are preferably made of urethane. Urethanes can have Shore ratings of, for example,  90 A,  95 A,  60 D, and  65 D, which may be suitable in various applications for various embodiments of the present invention. Furthermore, different spring members can be selected having different spring characteristics, such as, for example, without limitation, spring members having different hardness (Shore) ratings, or spring constants, depending upon the amount of dampening and the speed of return desired, as discussed further below. 
         [0024]    Referring to  FIG. 2 , during towing, when the towing vehicle and towed vehicle travel over surfaces of differing surface contour resulting in different angles of roll between the towing vehicle and towed vehicle, the grid head can pivot about a longitudinal axis, to provide roll of the grid head  2  with respect to the towing arm  50 . That is, for example, the swivel head  3  to which the grid head  2  is attached, can roll about the longitudinal axis “C” roughly in the direction of arrows “D,” with respect to the towing arm  50  and cassette assembly  22 . This can allow the grid head to pivot about a longitudinal axis with respect to the towing arm  50 . 
         [0025]    When the grid head  2  pivots, or rolls, with respect to the towing arm  50 , the shaft  4  can rotate about axis “C,” and the end portions of the pin  8  can move either up or down within the spring members  17 ,  18  to compress the spring members  17 ,  18 . The spring members  17 ,  18  can bias the return of the pin  8  to a level position, or roughly zero roll position with respect to the towing arm  50 . The speed of the return can be adjusted by using materials of different spring constants, as discussed above. 
         [0026]    In some embodiments, when nuts  19 ,  20  are used to secure the shaft within the cassette assembly  22 , they can be tightened to approximately 50 to 150 ft-pounds of torque. In some embodiments, once the swivel head assembly  1  has been assembled, the cassette assembly  22  can be received within the towing arm  50  and attached therein, such as by hex headed bolts. 
         [0027]    In some embodiments, during operation, the swivel head  3  can roll up to, for example, 30 degrees from horizontal when the grid head  2  is not horizontal because, for example, the towing is being done over uneven terrain. The amount of roll can be adjusted up to approximately 30 degrees by varying the sizes of the window  23  form by the cassette assembly  22  walls, such that the pin  8  abuts against the edges of the windows  23 , which serve as a stopping surfaces, when the roll angle is about 30 degrees from horizontal in either direction. As discussed above, the rate of return or dampening of roll motion or vibration can be adjusted by adjusting spring characteristics. In some embodiments, to avoid galling of shaft  4 , it is preferable that end plate  11  is made from bronze, thereby allowing the swivel head assembly  1  to hold loads of up to approximately 100,000 pounds. Also, in some embodiments, bearing  16  can be made from a composite material. One such bushing is, for example, the POLYLUBE® MRP bushing available from Polygon Company. 
         [0028]    Although specific embodiments and examples of the invention have been described supra (and in the attachments) for illustrative purposes, various equivalent modifications can be made without departing from the spirit and scope of the invention, as will be recognized by those skilled in the relevant art after reviewing the present disclosure. The various embodiments described can be combined to provide further embodiments. The described structures and methods can omit some elements or acts, can add other elements or acts, or can combine the elements or execute the acts in a different order than that illustrated, to achieve various advantages of the invention. These and other changes can be made to the invention in light of the detailed description. 
         [0029]    In general, in the following claims, the terms used should not be construed to limit the invention to the specific embodiments disclosed in the specification. Accordingly, the invention is not limited by the disclosure, but instead its scope is determined entirely by the following claims.