Abstract:
A coupler assembly for coupling a trailer to a towing vehicle hitch ball has a housing with an interior that defines a coupler socket adapted to receive a hitch ball. A ball clamp is disposed within the interior of the coupler housing and is movable toward and away from the coupler socket. The ball clamp has a clamping portion that retains the hitch ball within the coupler socket with the ball clamp positioned toward the coupler socket in a hitch ball retention position. A guide ramp is disposed within the coupler housing rearward of the coupler socket. The guide ramp projects toward the ball clamp and slopes upward and forward toward the coupler socket. A lateral guide member is disposed on the ball clamp rearward of the guide ramp. The lateral guide member cooperates with the guide ramp surface to limit forward movement of the ball clamp into the coupler socket.

Description:
BACKGROUND 
       [0001]    This invention relates to couplers. More particularly, it relates to a coupler assembly for coupling a trailer to a towing vehicle hitch ball wherein the coupler assembly has a guided ball clamp to facilitate proper coupling of the towing vehicle and the hitch ball. 
         [0002]    Trailer couplers are known. Typically, trailer couplers consist of a conformally-shaped socket that is close-fitting around a spherical hitch ball. The coupler also has securing means by which separation of the coupler and hitch ball is blocked. 
         [0003]    In certain coupler types, the primary component of this coupler securing means is called the ball shoe or ball clamp. When the hitch ball and coupler are in proper engagement, the ball clamp resides behind the hitch ball and prevents disengagement of the hitch ball from the coupler. 
         [0004]    A problem that sometimes occurs when a coupler is placed over a hitch ball is that the hitch ball does not properly enter into the socket portion of the coupler, the coupler is lowered over the hitch ball in such relationship that the hitch ball strikes the ball clamp from below and jams the ball clamp upward into the coupler where it is not in proper relationship with the hitch ball to prevent separation of the hitch ball and coupler. 
         [0005]    There is a need, therefore, for a coupler that addresses the foregoing problem. It is an object of the present invention to provide such an apparatus. 
         [0006]    Additional objects and advantages of the invention will be set forth in the description that follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations pointed out in the appended claims. 
       SUMMARY OF THE INVENTION 
       [0007]    To achieve the foregoing objects, and in accordance with the purposes of the invention as embodied and broadly described in this document, there is provided a coupler assembly for coupling a trailer to a towing vehicle hitch ball. The coupler assembly includes a coupler housing with an interior that defines a coupler socket adapted to receive a hitch ball. The coupler socket includes a bottom socket opening adapted to allow the insertion of the hitch ball into the coupler socket. The socket opening has a partially circumferential retaining rib. A ball clamp is disposed within the interior of the coupler housing and is movable toward and away from the coupler socket. The ball clamp has a clamping portion that cooperates with the socket opening retaining rib to retain the hitch ball within the coupler socket when the ball clamp is positioned toward the coupler socket into a hitch ball retention position. A guide ramp is disposed within the coupler housing rearward of the coupler socket. The guide ramp projects toward the ball clamp and slopes upward and forward toward the coupler socket. A lateral guide member is disposed on the ball clamp rearward of the guide ramp. The lateral guide member cooperates with the guide ramp surface to limit forward movement of the ball clamp into the coupler socket. 
         [0008]    According to one aspect of the invention, the lateral guide member includes a wing on the side of the ball clamp that defines a forward-facing guide surface sloped generally upward and forward toward the coupler socket. The wing on the side of the ball clamp also can define a rearward-facing guide surface sloped generally upward and forward toward the coupler socket. A rear guide ramp is disposed within the coupler housing rearward of the ball clamp rearward-facing guide surface. The coupler housing rear guide ramp slopes upward and forward toward the coupler socket and cooperates with the ball clamp rearward-facing guide surface to urge the ball clamp forward toward the coupler socket when the ball clamp is moved upward within the coupler housing. 
         [0009]    In this configuration, the guide ramp restricts unwanted movement of the ball clamp toward the coupler socket as the ball clamp is moved upward into the hitch ball retention position. If the hitch ball contacts the ball clamp from below as the trailer coupler is lowered over the hitch ball, the guide ramp and ball clamp guide member cooperate to restrict the ball clamp from moving forward, thereby assuring a sufficiently large opening for entry of the hitch ball into the coupler socket. This reduces the possibility that the hitch ball will jam the ball clamp forward and prevent the hitch ball from fully entering into the coupler socket. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate the presently preferred embodiments of the invention and, together with the general description given above and the detailed description of the preferred methods and embodiments given below, serve to explain the principles of the invention. 
           [0011]      FIG. 1A  is a side sectional view of a prior ball clamp trailer coupler showing the hitch ball secured within the coupler socket with the ball clamp positioned in contact with the hitch ball in a retention position. 
           [0012]      FIG. 1B  is a side sectional view of the coupler of  FIG. 1A  showing the hitch ball within the coupler socket with the ball clamp positioned away from the hitch ball in a release position. 
           [0013]      FIG. 1C  is a side sectional view of the coupler of  FIG. 1A , showing the ball clamp jammed into the socket by the hitch ball, resulting in the insecure engagement of the ball and socket. 
           [0014]      FIG. 2  is a side sectional view of a coupler assembly in accordance with one embodiment of the present invention, showing the ball clamp in a retention position securing the hitch ball within the coupler socket. 
           [0015]      FIG. 3  is a top perspective view of the ball clamp of the coupler assembly of  FIG. 2 . 
           [0016]      FIG. 4  is a bottom perspective view of the coupler housing of the coupler assembly of  FIG. 2 . 
           [0017]      FIG. 5  is a bottom plan view of the coupler assembly of  FIG. 2 , showing the relationship of the ball clamp and the guide ramps in the coupler housing. 
           [0018]      FIG. 6  is a bottom perspective view of the coupler assembly of  FIG. 2 , showing the ball clamp positioned in the release position. 
       
    
    
     DESCRIPTION 
       [0019]    Reference will now be made in more detail to presently preferred embodiments of the invention, as illustrated in the accompanying drawings. While the invention is described more fully with reference to these examples and drawings, the invention in its broader aspects is not limited to the specific details, representative devices, and illustrative examples shown and described. Rather, the description which follows is to be understood as a broad, leaching disclosure directed to persons of ordinary skill in the appropriate arts, and not as limiting upon the invention. 
         [0020]    For purposes of explanation, and to further assist in the understanding of this invention, a brief description of the operation of a standard previously-known ball and socket coupler mechanism follows. Referring to  FIGS. 1A-B , a standard coupler assembly  10  is shown, which includes a coupler  20  and hitch ball  22 . The hitch ball  22  is commonly affixed to the rear end of a tow vehicle, such as a truck or sport utility vehicle, utilizing a standard mounting device that can support the tongue weight of the vehicle to be towed. Similarly, the coupler  20  is affixed, by commonly known techniques, e.g. welding, bolting, etc., to the frame of the vehicle that is to be lowed, e.g. a trailer, thus forming an integrated frame unit. The coupler  20  has a housing  34  with a ball-shaped socket  24  for receiving the hitch ball  22  when the trailer is hitched to the tow vehicle. In operation the trailer coupler socket  24  is lowered onto the hitch ball  22 , from an elevated height relative to the hitch ball  22 , such that the socket  24  engulfs the hitch ball  22 . 
         [0021]    Still referring to  FIGS. 1A-B , the ball and socket coupler assembly  10  further includes a user rotatable handwheel  26 . The handwheel  26  is rotatably mounted upon a threaded member  29  such that rotation of the handwheel  26  draws or urges the threaded member  29  and a ball clamp  25  depending from the member  29  either toward or away from the hitch ball  22 . The ball clamp  25  has a forward-facing curved surface  32  that conforms to the curved surface of the hitch ball  22  and a rearward-facing guide surface  33  sloped generally upward and forward toward the coupler socket  24 . 
         [0022]    The coupler housing  34  includes a rear wall  28  opposite the coupler socket  24  and sloped generally upward and toward the coupler socket  24 . The sloped rear wall  28  urges the ball clamp  25  forward toward the coupler socket  24  when the ball clamp  25  is moved upward within the coupler housing  34 . Upon rotation of the handwheel  26  in the appropriate direction (usually clockwise), the ball clamp  25  is drawn upward and toward the hitch ball  22 , thereby decreasing the effective opening dimension of the socket  24  until the ball clamp  25  contacts the hitch ball  22  and secures it within the coupler socket  24 . In this retention position, as shown in  FIG. 1A , the ball clamp  25  cooperates with the socket  24  to prevent removal of the hitch ball  22  from the socket  24 . Similarly, upon rotation of the handwheel  26  in the opposite direction (typically counterclockwise), the ball clamp  25  is moved downward and away from the hitch ball  22  to a release position, shown in  FIG. 1B , which allows the hitch ball  22  to be released from the socket  24 . 
         [0023]    As shown in  FIGS. 1A-B , a spring loaded retaining tab  30  is usually provided in ball and socket hitches in order to maintain the ball clamp  25  in the retention position. The lab  30  has a projection  31  that engages recesses  27  formed in the periphery of the handwheel  26 . The tab  30  exerts a biasing force against one of the wheel recesses  27  to maintain the tab  30  in engagement with the handwheel  26 . When engaged, the tab  30  prevents rotation of the handwheel  26 , such rotation being permitted only when the projection  31  of tab  30  is pivoted away from the recess  27  in the handwheel periphery. 
         [0024]    During the rotation of the handwheel  26 , the retaining tab  30  is continually depressed by the operator. The depression of the tab  30  disengages the tab projection  31  from the recesses  27  formed in the periphery of the handwheel  26 . Upon positioning the handwheel  26  such that the coupler assembly  10  is in a coupled condition, the operator releases the tab  30  so that it engages one of the recesses  27  formed in the lower periphery of the handwheel  26 , thus securing the handwheel  26 . Minor additional rotation of the handwheel  26  may be required to properly align the tab  30  in one of the recesses  27 . Proper alignment of the tab  30  in one of the recesses  27  helps prevent the handwheel  26  from becoming inadvertently loosened by vibrations, or other unexpected forces. 
         [0025]    In the operation of the previously-known coupler illustrated in  FIG. 1A , the coupler  10  is first aligned over the hitch ball  22  with the ball clamp  25  in the release position, as shown in  FIG. 1B . The trailer is then lowered so that the socket cavity  24  engulfs the hitch ball  22 . After the hitch ball  22  is positioned in the socket cavity  24 , the handwheel  26  is then rotated to move the ball clamp  25  into the retention position shown in  FIG. 1A . In this position, the ball clamp  25  reduces the effective opening of the coupler socket  24  so that the hitch ball  22  can no longer be readily retracted from the coupler socket  24  and the coupler assembly  10  is securely coupled. 
         [0026]    With the previously-known coupler assembly  10 , during installation of the hitch ball  22  into the coupler socket  24 , the hitch ball  22  can strike the ball clamp  25  from below and jam the ball clamp  25  upward into the coupler socket  24  and into an insecure relationship with the hitch ball  22 , as shown in  FIG. 1C . This can result in unwanted separation of the hitch ball  22  from the coupler socket  24 . 
         [0027]    Having described the operational characteristics of a typical ball and socket coupler mechanism, the features of an improved coupler assembly according to the present invention will now be described. In accordance with the present invention, the ball clamp  25  cooperates with a guide ramp  36  within the coupler housing  34  so that movement of the ball clamp  25  is restricted to a path that assures a sufficiently large opening for entry of the hitch ball  22  into the coupler socket  24 . This lessens the possibility, during installation of the hitch ball  22  into the coupler socket  24 , that the hitch ball  22  will strike the ball clamp  25  from below and jam the ball clamp  25  upward into the coupler socket  24  as described above. 
         [0028]      FIGS. 2-6  depict various aspects of a coupler assembly  10  in accordance with a presently preferred embodiment of the invention. The interior of the coupler housing  34  includes guide ramps  36  (see, e.g,  FIG. 4 ). As described below in more detail, the guide ramps  36  engage the ball clamp  25  and limit forward movement of the ball clamp  25  toward the coupler socket  24 . 
         [0029]    As shown in  FIGS. 5-6 , the guide ramps  36  are disposed within the coupler housing  34  rearward of the coupler socket  24  and projecting toward the sides of the ball clamp  25 . The guide ramps  36  slope upward and forward toward the coupler socket  24 . As shown in  FIG. 4 , the guide ramps  36  are formed by projections  37  disposed on the interior walls of the coupler housing  34  that form a rearward-facing ramp surface. Lateral guide members  38  are provided, one on each of the opposite sides of the ball clamp  25 . Each of the guide members  38  projects outwardly from the ball clamp  25  and engages one of the guide ramps  36 . In one preferred embodiment, as shown in  FIG. 3 , the lateral, guide members  38  are formed as wings on the sides of the ball clamp  25  that define forward-facing guide surfaces  39 , which slope generally upward and forward toward the coupler socket  24  when the ball clamp is assembled with the coupler housing  34  (sec  FIGS. 5 and 6 ). 
         [0030]    In the operation, the guide ramps  36  restrict the forward movement of the guide members  38  and thereby restrict unwanted movement of the ball clamp  25  toward the coupler socket  24 . If the hitch ball  22  contacts the ball clamp  25  from below as the trailer coupler  10  is lowered over the hitch ball  22  (e.g., as shown in  FIG. 1C ), the guide ramps  36  and ball clamp guide members  38  cooperate to restrict the ball clamp  25  from moving forward, thereby assuring a sufficiently large opening for entry of the hitch ball  22  into the coupler socket  24 . This reduces the possibility that the hitch ball  22  will jam the ball clamp  25  forward and prevent the hitch ball  22  from fully entering into the coupler socket  24 . The trailer then can be lowered such that the socket cavity  24  engulfs the hitch ball  22  therein (e.g., as shown in  FIG. 1B ). 
         [0031]    After the hitch ball  22  is positioned in the socket cavity  24 , the handwheel  26  is then rotated, as previously described, thereby drawing the ball clamp  25  upward. As this occurs, the angular orientation of the guide ramps  36  allows the ball clamp  25  to move forward toward the hitch ball  22  until the ball clamp  25  reaches the retention position shown in  FIG. 1A . In this position, the ball clamp  25  reduces the effective opening of the coupler socket  24  and contacts the hitch ball  22  so that it cannot be readily retracted from the coupler socket  24 . The operator then aligns the tab  30  in one of the recesses  27  and releases the lab  30  to secure the handwheel  26  as previously described. 
         [0032]    Upon reading this disclosure, those skilled in the art will appreciate that various changes and modifications may be made to the preferred embodiments of the invention and that such changes and modifications may be made without departing from the spirit of the invention. Therefore, the invention in its broader aspects is not limited to the specific details, representative devices, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the general inventive concept.