Abstract:
A gas spring is mounted through a unique mount structure including a socket joint. The socket joint is mounted in a yoke for rotation through 180° about an axis of the yoke. The inventive structure provides greater freedom of movement than the prior art, and in many applications will allow rotation for more than 180°.

Description:
RELATED APPLICATION 
   The application claims priority to U.S. Provisional Application No. 60/520,102, filed on Nov. 14, 2003. 

   BACKGROUND OF THE INVENTION 
   This invention relates to a yoke connection allowing 180° of rotation for the connection of a gas spring to a base. 
   Gas springs are utilized to provide a linkage between two components, at locations where movement between the components needs to be limited at certain times. One common example is a linkage between a closure, such as liftgate or trunk, and a body on a motor vehicle. 
   Typically, the gas spring includes a mount on one of the closure and the body. The mount includes a member received in a socket to provide freedom of rotation about at least one axis. However, in this configuration, the amount of available rotation is limited, at least about one axis of freedom. The prior art has typically required an additional bracket to provide an acceptable range of movement. 
   It would be desirable to provide a greater degree of freedom of rotation about a desired axis, and to eliminate the required bracket. 
   SUMMARY OF THE INVENTION 
   In a disclosed embodiment of this invention, a gas spring is connected to a structure through a ball and socket combination. The socket is mounted within a yoke such that the socket can rotate within a large angle of freedom relative to the yoke. In the disclosed embodiment, the yoke and socket is utilized to mount a closure to a vehicle body. However, other applications would benefit from this invention. The inventive yoke provides additional freedom of rotation on the order of 180°. Thus, no extra bracket to provide a distinct mount location is necessary. 
   The ball and socket combination may be as known in the art. The socket may receive an intermediate resilient member and a clip member to secure the ball within the socket. Such ball and socket combinations are known in the gas spring art. While the ball and socket combination provides a universal connection in theory, in practice, rotation about at least one axis is limited. The yoke connection provides additional freedom of movement about this axis. 
   An alternative arrangement has a socket receiving a member for rotation about a single axis. Again, this type combination is as known in the gas spring art. 
   The gas spring is disclosed to connect a closure to a vehicle body. One end of the gas spring, defined by an end of a piston rod, is secured to one of the closure and the vehicle body, and another end of the gas spring, defined by a cylinder, is secured to the other of the vehicle body and the closure. A yoke mount, as described above, may be utilized at either one, or both ends. 
   These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  shows a prior art liftgate mount arrangement. 
       FIG. 1B  shows a bracket often required in the prior art. 
       FIG. 1C  shows a problem that would exist in the prior art without the additional bracket. 
       FIG. 2A  schematically shows a benefit of the inventive embodiments. 
       FIG. 2B  shows further freedom of movement from the inventive embodiments. 
       FIG. 3A  shows a first embodiment incorporating the subject invention. 
       FIG. 3B  is an opposed view of the first embodiment. 
       FIG. 3C  is a cross-section through the first embodiment. 
       FIG. 3D  is an exploded view of the first embodiment. 
       FIG. 4A  shows a second embodiment. 
       FIG. 4B  is an exploded view of the second embodiment. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1A  shows a prior art arrangement  20  for mounting a liftgate  22  on a vehicle body  23 . As shown, a gas spring  11  holds the liftgate  22  at an upwardly spaced position. The gas spring  11  is attached through socket connections  12  at each spring end. 
   As known, the gas spring  11  includes a piston  9  movable within a cylinder  8 . While it is desirable to provide free relative movement between the gas spring  11 , the liftgate  22  and the vehicle body  23 , in fact, the amount of available movement of the gas spring  11  along at least one axis is limited due to the socket connection  12 . 
   As shown schematically in  FIG. 1B , the frame  100  of the vehicle (which might be part of the vehicle body  23  or the liftgate  22 ) must receive a bracket  102  to move a mounting ball  104  to a position spaced 90° from a plane of the frame  100 . As will be explained below, the mounting ball  104  receives a socket structure. 
   As shown in  FIG. 1C , the socket structure  106  may be connected such as to the piston rod  9 . However, if the ball  104  is mounted to be generally parallel to the frame  100 , and without the bracket  102 , then the socket  106  might only be movable through a very limited range of movement relative to the frame  100 . This range of movement is too limited for the mounts to be readily utilized in many applications, and may be on the order of 30°. Thus, the brackets  102  have typically been utilized. 
     FIG. 2A  schematically shows the use of a yoke  24  to connect the ball  104  to the frame  100 . The ball may be simply bolted to the frame  100 , and the yoke  24  mounted to a socket member  108 . As can be appreciated from  FIG. 2A , the yoke  24  pivots about an axis X, and would have freedom of movement much greater than that provided by the  FIG. 1C  embodiment. 
   As can be appreciated from  FIG. 2B , the freedom of movement within a plane of the axis X could be universal depending on the detail of the socket  108 , and the ball  104 . The movement provided about the axis X is in addition to this prior art movement. 
   As shown in  FIG. 3A , the present invention includes a gas spring incorporating a yoke  24  that pivotally receives pins  26  from a socket  28 . In the embodiment shown in  FIG. 2A , a ball  36  is received in socket  28  and secured by a clip  30 . The structure of ball  36 , socket  28  and clip  30  is generally as known. In the prior art, the piston  9  was mounted directly to the socket. Here, the piston  21  (or the cylinder, not shown) is mounted to the yoke  24 . 
   The piston  21  is received within a cylinder (not shown) in a manner similar to that shown in  FIG. 1 . As shown in  FIG. 3B , clip  30  may secure a ball  36  ( FIG. 3C ) which is fixed to a mount structure  100 , such as either or both of the body  23  and the liftgate  22 . Piston  21  is attached to yoke  24 . It should be appreciated a similar connection can be utilized between another mount location. This can be understood from  FIG. 1A .  FIG. 3D  is an exploded view that shows further detail. 
   As shown, the socket  28  includes an inner member  34  and clip  30 . As also shown in  FIG. 3B , socket  28  includes side mount structures  40  on each side of the clip  30 . 
   Side mount structures  40  carry pins  26  for pivoting movement through pin holes  38  in the yoke  24 . Due to the ball  36  and socket  28  mount, the gas spring can move relative to vehicle body  23  (or liftgate  22 ) as in the prior art. However, about the axis of the pins  26 , there is additional freedom of movement due to the inventive structure. 
     FIG. 4A  shows another embodiment wherein a socket  50  is attached to a gas spring piston  21  through yoke  24 . As with the first embodiment, a similar connection can also be utilized for the cylinder. Socket  50  has pins  59  pivotally mounted in yoke  24 . A central member  52  is supported in socket  50 . This structure operates similarly to the  FIG. 3A–3D  embodiments, however, the capture of the central member within the socket  50  is distinct. As known in the art, central member  52  can rotate about its elongate axis x within socket  50 .  FIG. 4B  shows an exploded view of this embodiment. 
   The inner structure for holding the balls within the sockets may be as known in the art, and forms no portion of this invention. While two examples are shown, other types of connecting members and sockets come within the scope of this invention. Moreover, while only a liftgate is illustrated, other vehicle closures, and other non-vehicle applications, would benefit from a gas spring mount such as disclosed in this application. 
   While many manufacturing techniques can be utilized to make the inventive mount structures, it is preferred that the yoke and the socket are molded in a two-shot molding process, such that they are molded to each other, while still allowing the movement as described above. A worker of ordinary skill in the art would recognize how to provide such movement. Further, portions of the mount connections can be insert molded into the two-shot mold process. 
   Although preferred embodiments of this invention have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.