Patent Abstract:
An anti-rattle hitch ( 100 ) includes a tubular insert ( 102 ) that is configured to be inserted into a receiver ( 90 ). A wedge mechanism comprising a first wedge member ( 112 ) and a second wedge member ( 114 ) are disposed in the insert, and have slidably engaged angled faces. The second wedge member includes one or more pistons that extend through piston ( 110 ) apertures in the insert such that the longitudinal position of the second wedge member is fixed. An adjustment member ( 120 ) adjusts the position of the first wedge member, thereby adjusting the piston position which can be biased against the receiver.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of patent application Ser. No. 12/777,163, filed May 10, 2010, which claims the benefit of Provisional Application No. 61/177,203, filed May 11, 2009, the entire disclosures of which are hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     Hitch assemblies provide a connection between a device, such as a trailer, ski rack, or the like, and a vehicle. A receiver-type hitch assembly typically includes a receiver that is attached to the frame of a vehicle and a hitch that is removably inserted into the receiver. The hitch may include, for example, a conventional trailer ball that is sized to be engaged by a ball receiver on a trailer. Alternatively, the hitch may comprise a portion of a carrier, for example, a bicycle carrier, ski carrier, cargo carrier, or the like. The hitch may include additional or alternative mechanisms for engaging an apparatus to be carried or towed. A conventional SAE receiver typically comprises a rectangular tube with a rearwardly facing square opening that is 1.25 inches (32 mm), 2.0 inches (51 mm) or 2.5 inches (64 mm) square. 
     The insertable hitch includes a shaft having an outer dimension that is somewhat smaller than the inner dimension of the receiver so that the hitch can be relatively easily inserted into the receiver. A hitch pin (or locking pin) is inserted through holes provided in the side walls of the receiver and alignable holes in the hitch. The locking pin may be secured, for example, with a retaining clip to prevent the locking pin from inadvertently coming out during use. Exemplary prior art hitch assemblies include those disclosed in U.S. Pat. No. 6,105,989, to Linger, which is hereby incorporated by reference in its entirety, and in U.S. Pat. No. 6,382,656, to Johnson, Jr., which is hereby incorporated by reference in its entirety. 
     Detachable hitches are preferred for many applications. For example, a user may use one hitch for towing loads and other hitches for attaching bicycle racks, ski racks, carriers, or the like, to the vehicle. Also, hitches typically extend beyond the rear of the towing vehicle to enable attachment of a trailer to the hitch with clearance for the trailer and towing vehicle to articulate relative to each other during towing. The protruding hitch with a ball attachment can be bothersome and dangerous when the vehicle is used without the trailer attached; therefore, it is beneficial to be able to remove the hitch when it is not needed. 
     However, as noted above the hitch shaft is smaller than the receiver opening, and so the fit between the hitch and the receiver includes some play between the receiver and the walls of the hitch shaft. The relatively loose fit permits undesirable relative movement or play between the receiver and the hitch, which can be noisy and annoying. The play between the walls of the receiver and hitch can cause clanging noises and vibrations that can be felt by operators and passengers within the towing vehicle. The play may also be magnified by the lever arm of the hitch so that it is felt more strongly by the trailer. That same play can also increase wear and stress on various parts of the mechanisms attaching the trailer to the towing vehicle, leading to undesirable wear and fatigue. 
     The disadvantages of the relatively loose fit between the receiver and hitch coupling have been recognized by others. For example, in U.S. Pat. No. 6,974,147, to Kolda, which is hereby incorporated by reference, a mechanism for preventing relative movement between these members is disclosed, wherein the tow bar or mounting member is provided with a cam that is adjustably urged into the mounting member and abuts the hitch pin. The adjustment mechanism causes the cam to rotate, extending through a slot in the mounting member, and is urged against the receiver. However, the mechanism has the disadvantage that it presses against the receiver at a single position and against the opposite side of the mounting member at a single position, in addition to the hitch pin, which may still permit some movement between the mounting member and receiver. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     An anti-rattle hitch is disclosed having an insert that is configured to be inserted into a receiver. For clarity, the hitch will be described with directional references, such as “upper” and “lower,” although it will be appreciated that the particular orientation may be different. The insert has an upper wall with a piston aperture, a lower wall, and two side walls. A lower wedge block and an upper wedge block are disposed in the insert. The lower wedge block has a lower surface that slidably engages the lower wall of the insert, and an upper angled surface. The upper wedge block has a lower angled surface that slidably engages the lower wedge block, and a piston that extends through the piston aperture, such that the longitudinal position of the upper wedge block is constrained by the piston. An adjustment member engages the lower wedge block, extends out of the insert, and is operable to adjust the longitudinal position of the lower wedge block, thereby adjusting the transverse position of the upper wedge block. This configuration allows adjusting the position of the piston that extends out of the insert. The hitch is configured such that the piston may be adjusted to press against the receiver, thereby locking the hitch therein and avoiding play therebetween. 
     In an embodiment of the invention, the piston comprises a cylinder that is attached to the upper wedge member with a screw. 
     In an embodiment of the invention, a second piston aperture is provided through the insert, and a second piston is attached to the upper wedge block and extends through the second piston aperture. 
     In an embodiment of the invention, the hitch includes a ball mount member that is configured to support a tow ball. 
     In an embodiment of the invention, the adjustment member is a threaded rod that threadably engages the first wedge member and a head that extends out of the tubular insert. 
     In an embodiment of the invention, the adjustment member includes a security feature, such as a lock or a keyed head, that hinders operation of the adjustment member without a corresponding tool. 
     In an embodiment of the invention, a low friction panel is provided between the angled faces and may comprise an ultrahigh molecular weight polyethylene. 
     In an embodiment of the invention, the wedge blocks further include second angled faces that are slidably engaged. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1A  is a perspective view of a hitch assembly in accordance with the present invention; 
         FIG. 1B  is another perspective view of the hitch shown in  FIG. 1A ; 
         FIG. 2  is an exploded view of the hitch assembly shown in  FIG. 1A ; and 
         FIG. 3  is a cross-sectional view of the hitch assembly shown in  FIG. 1A . 
         FIG. 4  is a fragmentary end view of the hitch shown in  FIG. 1A . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1A  is a perspective view of a hitch assembly  100  in accordance with the present invention and showing in phantom a receiver  90  and a tow ball  101 . A three-quarter rear perspective view of the hitch assembly  100  is shown in  FIG. 1B . The hitch assembly  100  includes a tubular insert  102  that is sized and configured to be inserted into a receiver  90  to cooperatively comprise a receiver-type hitch assembly. The tubular insert  102  is a substantially square tube. In an exemplary embodiment the tubular insert  102  is sized to engage an SAE standard receiver having a square opening that is 1.25 inches (32 mm), 2.0 inches (51 mm) or 2.5 inches (64 mm) on each side. The tubular insert  102  is fixedly attached to a structural member, for example a ball mount  103  that is configured to support a tow ball  101 . For example, the tow ball  101  ( FIG. 1A ) may bolt through aperture  107  ( FIG. 1B ) in the ball mount  103 . An optional gusset plate  105  reinforces the connection between the tubular insert  102  and the ball mount  103   
     The tubular insert  102  includes a first wall  102 A (in this case the upper wall), oppositely disposed second and third walls  102 B,  102 C (e.g., side walls), and a fourth wall  102 D (e.g., lower wall) disposed opposite the first wall  102 A. As seen most clearly in the exploded view of  FIG. 2 , the first wall  102 A includes a pair of longitudinally spaced piston apertures  104 . The second and third walls  102 B,  102 C each have a locking pin aperture  106  (one visible), which are aligned to receive a conventional locking pin (not shown). Corresponding locking pin apertures  96  are provided through the receiver  90 . Also visible in  FIG. 1A  are a pair of adjustable pistons  110 , which are discussed in more detail below. 
       FIG. 2  shows an exploded view of the hitch  100 . Refer also to  FIG. 3 , which shows a longitudinal cross-sectional view of the hitch  100 , taken through a centerline of the tubular member  102 . A sliding wedge mechanism is disposed in the tubular insert  102  and is operable to selectively tighten the hitch  100  within the receiver  90 , thereby reducing or eliminating play between the hitch  100  and the receiver  90 . The wedge mechanism includes a first wedge member  112 , defining a first angled face  112 A, a second angled face  112 B and a recess  112 C therebetween. A threaded aperture  113  is oriented longitudinally from a proximal end of the first wedge member  112 . 
     A second wedge member  114  is positioned generally adjacent the first wedge member  112  and includes a first angled face  114 A, a second angled face  114 B, and a recess  114 C therebetween. When assembled, the first wedge member first angled face  112 A is disposed adjacent the second wedge member first angled face  114 A, and the first wedge member second angled face  112 B is disposed adjacent the second wedge member second angled face  114 B to slidably engage the first wedge member  112  when the hitch  100  is assembled. 
     The pistons  110  are attached to an upper face  114 D of the upper block  114 . In the present embodiment the attachment is accomplished with flathead fasteners  110 A, although other attachment means may be used, including for example by forming a post (threaded or unthreaded) on the bottom of the pistons, with corresponding apertures in the second wedge member  114 . Optionally, recesses  114 E are provided in which the pistons  110  are securely seated. 
     A threaded adjustment fastener  120  extends through an aperture  108  in the ball mount  103  and into the tubular insert  102  to threadably engage the first wedge member  112  threaded aperture  113 . Optionally, an angled spacer  122  and spring, or other biasing member  124 , are also provided. It will now be appreciated that the longitudinal position of the second wedge member  114  is constrained within the tubular insert  102  by the pistons  110  extending through the piston apertures  104 . The position of the first wedge member  112  is adjusted with the adjustable fastener  120 . 
     The first and second wedge members  112 ,  114  angled faces  112 A,  114 A, and  112 B,  114 B are configured to slidably engage. In this embodiment, low friction pads  118  are provided between the respective angled faces. For example, low friction pads may comprise polymeric material. In a current embodiment, the low friction pads comprise ultrahigh molecular weight polyethylene, which has a very low coefficient of friction, is self-lubricating, and is highly resistant to abrasion. 
     The wedge member recesses  112 C,  114 C are sized and shaped to cooperatively define an opening therebetween that is aligned with the locking pin apertures  106  in the tubular insert  102  (which are also alignable with corresponding apertures  96  in the receiver  90 ), such that the wedge members  112 ,  114  will not interfere with the locking pin during use. 
     A fragmentary end view of the hitch  100  is shown in  FIG. 4 , showing the first wedge member  112  and the lower portion of the tubular insert  102 . In this embodiment, the lower surface of the first wedge member  112  is provided with longitudinal ribs  112 D to reduce friction between the first wedge member  112  and the tubular member  102 , and thereby facilitate adjustment of the wedge mechanism. It is further contemplated that a low friction panel or other friction-reducing mechanism (not shown) may be provided between the first wedge member  112  and the tubular insert  102 . 
     In the present embodiment, the hitch  100  is assembled by inserting the adjustment member  120  through the aperture  108  in the ball mount  103  and inserting the angled spacer  122  and spring  124  through the open end of the tubular insert  102  to slide over the adjustment member  120 . The first and second wedge members  112 ,  114  are inserted together into the tubular insert  102  and the adjustment member  120  engages the threaded aperture  113 . The second wedge member is then positioned such that the recesses  114 E are aligned with the piston apertures  104 , and the pistons  110  are inserted through the respective piston apertures  104  and attached to the second wedge member  114 . 
     To use the hitch  100 , the adjustment member  120  is adjusted such that the pistons  100  are approximately flush with the first wall  102 A of the tubular insert  102 . The hitch  100  may then be inserted into the receiver  90 . The adjustment member  114  is then adjusted such that the first wedge member  112  is drawn to the right in  FIG. 3 , as indicated by arrow  80 . The second wedge member  114  is restrained from moving longitudinally by the pistons  110 . Due to the angled faced of the first and second wedge members  112 ,  114 , the second wedge member  114  moves upwardly as indicated by arrow  81 , such that the pistons  110  move upwardly to engage and press against the receiver  90 , as indicated by arrows  82 . The locking pin (not shown) is then inserted through the locking pin apertures  96 ,  106 . 
     To disengage the hitch  100  from the receiver  90 , the adjustment member  120  is adjusted in the reverse direction. After removing the locking pin, the adjustment member  120  is adjusted in the opposite direction. The biasing spring  124  aids in moving the first wedge member to the left in  FIG. 3 , and the pistons  110  disengage from the receiver  90 , such that the tubular insert  102  can be readily pulled out of the receiver  90 . 
     It is also contemplated that the adjustment member  120  may include one or more security features, such as a lock or the like. In an embodiment the adjustment member incorporates an unusual head shape, such that the adjustment member is not easily adjusted without a corresponding, suitably keyed tool (not shown). This security feature provides the additional advantage that once the hitch  100  is securely locked to the receiver  90 , the hitch  100  cannot be easily removed from the vehicle without the special tool. This will provide the additional advantage of protection from theft. 
     Although not required for the present invention, in an exemplary embodiment the first and second wedge members  112 ,  114  may be formed from a relatively soft material such as aluminum or a composite material, and the tubular insert  102  and ball mount  103  may be formed from a conventional rugged material such as steel. 
     As discussed above, the hitch  100  may alternatively be configured as a portion of any hitchable device, for example, a bicycle carrier, ski carrier, or the like. Also, although the current hitch  100  includes two generally cylindrical pistons  110  that engage the receiver  90 , it would be straightforward to change the number of pistons and/or to use other shapes or sizes of members for engaging the receiver. For example, it is contemplated that the second wedge member  114  may be provided with four smaller pistons or protrusions disposed generally at the corners of the second wedge member  114 , with corresponding apertures in the tubular sleeve member  102 . 
     Although a currently preferred embodiment has been described, many modifications may be made to this embodiment without departing from the present invention. For example, it is contemplated that the first and second wedge members  112 ,  114  may be formed from some alternate material, such as a polymer or composite material. Also, where threadable connections are shown, it will be appreciated that other connection means, as are known in the art, may alternatively be used. It is also contemplated that a cover or other blocking means may be provided on the end of the tubular sleeve member  102 , to deter foreign matter from entering the member. 
     While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.

Technology Classification (CPC): 1