Abstract:
A method and structure for installing an automotive suspension member is herein disclosed. A fastener used to couple a link member includes a head, a shaft extending from the head and a self-holding mechanism that prevents rotation of the fastener when it is engaged with an aperture formed through a mating member. The self-holding mechanism obviates the need for more than one tool for installing the link member.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is related to and claims the benefit of Provisional Application Ser. No. 60/347,619 filed on Jan. 10, 2002. 

   FIELD OF THE INVENTION 
   The present invention relates to a method and structure for installing fasteners in inaccessible locations. More particularly, the present invention relates to a method and structure for installing automotive suspension mechanisms. 
   BACKGROUND OF THE INVENTION 
   Installing threaded fasteners in hard to reach places has always been difficult. This is especially so where multiple tools are required to install the fastener. A typical scenario of this type requires a first tool, such as a box end wrench or the like, to be engaged with a head of the fastener to prevent rotation of the fastener as a second tool threads a nut onto the shaft of the fastener. This is not difficult where the threaded fastener is readily accessible. However, where the fastener is located in a hard to reach location, such as within the undercarriage or suspension of an automobile or other similar location, the installation of a threaded fastener may be extremely difficult, resulting in damage to the fastener, injury to an installer, and may sometimes require specialized tools. 
   Where a fastener is difficult to access, or where the head of a fastener may not be grasped for fear of damage, grasping structures have been formed on the shaft of the fastener. As can be seen in  FIG. 2 , one prior art structure includes a squared tip  12  on the shaft  14  of the prior art fastener  10 . In use, a nut  16  is first threaded onto the shaft  14  of the prior art fastener  10  past the squared tip  12  until the nut  16  abuts the structure  20  through which the prior art fastener  10  is received. At this point, an installer addresses a first tool, such as a box end wrench (not shown), to the squared tip  12  of the fastener  10  so as to prevent rotation of the fastener  10  as a second tool is used to drive the nut  16  onto the shaft  14  until an appropriate amount of torque has been applied to the nut  16 . 
   Unfortunately, where a fastener such as prior art fastener  10 , is installed in an awkward position, such as where one or more fasteners are used to secure a link member in an automobile suspension system such as, for example, an end link of a sway bar assembly between an automobile suspension and a stabilizer bar, it becomes awkward or even impossible to utilize two tools in the installation of the fastener. In these types of situations, it would be desirable to provide a structure on a fastener that prevents rotation of the fastener relative to the stabilizer bar or automobile suspension. In this manner, an installer of the link member need use only a single tool, such as a box end wrench or torque wrench, to properly seat a nut on the fastener. 
   SUMMARY OF THE INVENTION 
   The present invention is realized in a fastener system that prevents relative rotation between the fastener and an aperture in which the fastener is received. The prevention of relative rotation between the fastener and the aperture in which it is received obviates the need for more than a single tool in installing this fastener. In a preferred embodiment, the present invention comprises a fastener having a head from which extends a shaft. The head of the fastener is captured in an associated receptacle in an end of a link member of a suspension assembly to form a joint therebetween. The shaft of the fastener is preferably threaded and has formed thereon adjacent the head a non-circular portion. The non-circular portion of the fastener is constructed and arranged to engage a complementarily shaped inner surface of an aperture into which the fastener has been inserted such that when the non-circular portion of the fastener and the similarly shaped interior surface of the aperture are operatively engaged, there can be no rotation of the fastener within the aperture. To achieve this end, the non-circular portion of the fastener may have a “D” shape, a double “D” shape, a hexagonal, square, splined, multi-faceted, triangular, or multi-lobular shape. 
   Such a fastener facilitates a simplified method for installing a suspension link member in an automobile that requires only a single tool at any given time for the installation thereof. Obviously, before beginning, any preexisting suspension assembly that is installed in the vehicle must be removed or disassembled. Once this has been accomplished, the method of the present invention may be implemented. The first step of the present invention is to provide a suitable suspension system that will impart the desired handling characteristics to the automobile. In one embodiment, a stabilizing bar is secured to the frame of the automobile, as by slip fit bushings, in such a manner as to allow the stabilizing bar to rotate about a longitudinal axis thereof. A pair of end links is next coupled to the respective ends of the stabilizer bar using fasteners constructed and arranged according to the present invention. In a preferred embodiment, the fasteners used to secure the end link to the stabilizer bar have a head that is captured in a socket in the end of the end link. Each fastener has a shaft that extends from its head and has a non-circular portion that is formed in the shaft adjacent to the head or perhaps between the shaft and the head. The non-circular portion of the shaft of the fastener is constructed and arranged to operatively engage an aperture formed through the end of the stabilizer bar that has a similarly shaped inner surface. The operative engagement of the non-circular portion of the fastener with the complementarily formed inner surface of the aperture in the stabilizer bar prevents the rotation of the fastener with respect to the stabilizer bar. A standard nut is then threaded onto the shaft of the fastener and the appropriate torque is applied thereto using only a torque wrench or a box-end wrench. To complete the installation, the remaining free ends of the end links are coupled to a lower control arm of the automobile&#39;s suspension using either a fastener constructed and arranged according to the present invention as previously described, or with a standard prior art fastener as is known. Although the invention has been summarized in conjunction with a stabilizer bar, the invention can be utilized with other members, including other linking members of an automobile suspension system. 
   These and other objects, aspects, features and advantages of the present invention will become more fully apparent upon careful consideration of the following Detailed Description of the Invention and the accompanying Drawings, which may be disproportionate for ease of understanding, wherein like structure and steps are referenced generally by corresponding numerals and indicators. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view of an automobile illustrating a typical prior art automobile suspension having a sway bar assembly coupled thereto; 
       FIG. 2  is a partial cross-sectional view of a prior art fastener; 
       FIG. 3  is a partial cross-sectional view of a fastener of the present invention; 
       FIG. 4  is a plan view of an end link of a sway bar assembly incorporating fasteners of the present invention; and, 
       FIGS. 5A-H  are cross-sectional views of non-circular structures of the fastener of the present invention taken along lines  5 — 5  of FIG.  4 . 
   

   Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. 
   DETAILED DESCRIPTION 
     FIG. 1  illustrates an automobile  30  that is in the course of making a turn. As the automobile  30  negotiates a curve in the direction indicated by arrow  40 , the automobile  30  tilts away from the direction of the curve as indicated by the angle A created between the horizontal surface  42  upon which the automobile rests and the mid-plane  44  of the auto  30 . The rotation of the automobile  30  is caused by centrifugal effects that are applied to the automobile  30  in a direction opposite that of the curve  40 . 
   The automobile  30  is provided with a suspension system  31  that is capable of accommodating the centrifugal effects described above. The exemplary suspension system  31  comprises a frame  32  and wheels  34  that are coupled to the frame  32  by independent suspension mechanisms that include an upper control arm  36  and a lower control arm  38 . As shown, the rotation of the automobile  30  to angle A causes the suspension of the left-hand wheel  34  to be compressed upwardly, whereas the suspension of the right-hand wheel  34  extends downwardly. In order to minimize the rotation defined by angle A, a sway bar assembly  50  comprising a stabilizing bar  52  may be coupled between the respective lower control arms  38 . The stabilizing bar  52  is rotatably coupled to the frame  32  of the automobile  30  by bushings  54 . These bushings allow the stabilizing bar  52  to rotate freely with respect to the frame  32  of the automobile and to have some degree of lateral motion as well. The ends  56  of the stabilizing bar  52  are coupled to end links  58 , which are in turn secured to the lower control arms  38  of the respective right and left wheels  34 . In this manner, the right and left lower control arms  38  are resiliently coupled through the stabilizing bar  52  so as to limit the rotation of the automobile  30  as it negotiates a curve. 
     FIG. 3  is a partial cross-section of an end link  58  and an appurtenant fastener  60  that has been adapted to allow installation with only a single tool according to the present invention. Fastener  60  comprises a head  64  from which extends a shaft  66 . Between the head  64  and the shaft  66  there is formed a non-circular portion  70 . The fastener  60  may also be provided with a shoulder  63  that limits the insertion of the shaft  66  of the fastener  60  into a bore or aperture  72 . The non-circular portion  70  of the fastener  60  is constructed and arranged to engage an interior surface of an aperture  72  formed in a suspension member  73 , which can be, for example, stabilizer bar  52  or lower control arm  38  or other linking member, as the case may be. The non-circular portion  70  of the fastener  60  and the interior surface of the aperture  72  in which it is received are complementary with one another in that their engagement prevents relative rotation between the fastener  60  and the aperture  72 . 
   As can be seen in  FIG. 3 , the head  64  of fastener  60  may comprise the ball portion of a ball and socket joint. Alternatively, a ring link or bushing link or any other suitable joint member could be utilized. The end link  58  comprises a socket  65  or other associated receptacle into which head  64  of fastener  60  is rotatively received. The ball and socket coupling of the fastener  60  to the end link  58  allows for relative movement and misalignment that might otherwise damage the sway bar assembly  50 . The end link  58 , as shown in  FIG. 4 , may comprise a ball and socket joint with the head  64  of a fastener  60  received in a socket  65  at each end. Alternatively, the end link  58  may utilize a single fastener  60  to secure the end link  58  to the stabilizer bar  52  and a standard, prior-art fastener to secure the remaining end of the end link  58  to the lower control arm  38 , or vice versa. 
   The cross-sectional shape of the non-circular portion  70  of the fastener  60  may take many forms. A number of these forms are illustrated in  FIGS. 5A-H .  FIG. 5A  illustrates a non-circular portion  70  having two flats formed therein in a configuration that is commonly referred to as a “double D” configuration.  FIG. 5B  illustrates a hexagonal non-circular portion  70  while  FIG. 5C  illustrates the non-circular portion  70  as being four-sided and square.  FIG. 5D  illustrates a “splined” non-circular portion  70  that includes longitudinal splines.  FIG. 5E  illustrates a non-circular portion  70  that is multi-faceted. Note that the non-circular portion  70  may have any suitable number of facets.  FIG. 5F  illustrates a non-circular portion  70  having a single facet and  FIG. 5G  illustrates a non-circular portion having three facets that form a triangle.  FIG. 5H  illustrates a non-circular portion  70  having a multi-lobular cross-sectional shape similar to the splined non-circular portion  70  illustrated in FIG.  5 D. It is to be understood that the cross-sectional shape of the non-circular portion  70  is not to be limited to those illustrated in  FIGS. 5A-H . 
   Using the fastener  60  of the present invention, a sway bar assembly  50  may be easily installed. The first step in this process is to remove the existing sway bar assembly, if any exists. Next, bushings  54  are placed on the stabilizing bar  52  in predetermined positions dictated by the mounting locations provided on the frame  32  of the automobile  30 . The bushings  54  are then installed by driving one or more fasteners into the frame  32 . Note that the bushings  54  may be installed using standard fasteners or fasteners  60  that are constructed and arranged according to the present invention. In the case (not shown) in which fasteners  60  are used, the shafts  66  of the fasteners  60  are inserted into a bore  72  formed through the bushing  54  and the frame  32  such that the non-circular portion  70  of the fastener  60  engages the interior of the bore  72  formed through the bushing  54  and the frame  32 . A nut  74  is then threaded onto the shaft  66  of the fastener that extends through the frame  32 . Once the nut  74  is substantially in its desired position abutting the frame  32  of the automobile, a single tool such as a box end wrench or a torque wrench may be used to tighten the nut  74  to a predetermined torque level. 
   After the stabilizer bar  52  has been coupled to the frame  32  of the automobile  30 , an end link  58  is coupled to each end  56  of the stabilizer bar  52 . A fastener  60  is connected to each end link  58  by capturing head  64  in socket  65 . One end of fastener  60  thereby is connected to stabilizing bar  52 . Alternatively, the structures illustrated in the exemplary embodiment shown can be reversed. In such embodiment, the shaft  66  of a fastener  60  is inserted into an aperture  72  formed through the end  56  of the stabilizing bar  52  until the non-circular portion  70  of the fastener  60  engages the interior of the aperture  72 . Once the non-circular portion  70  of the fastener  60  is engaged in the aperture  70 , a nut  74  is threaded onto the shaft  66  and tightened using only a single tool such as a torque wrench or box end wrench. 
   Next, the end link  58  is coupled to the lower control arm  38 , preferably using a fastener  60 , though it is to be understood that the end link  58  may be secured to the lower control arm  38  using other types of fasteners. However, where fasteners  60  are used, as described above and shown in the drawings, the shaft  66  of the fastener  60  is inserted into an aperture  72  formed in the lower control arm  38  until the non-circular portion  70  of the shaft  66  engages the complementary inner surface of the aperture  72  so as to prevent relative rotation therebetween. Once the non-circular portion  70  of the fastener  60  is engaged in the aperture  72 , a nut  74  is threaded onto the shaft  66  and tightened using only a single tool such as a torque wrench or box end wrench. 
   Although the invention has been primarily described in connection with a sway bar assembly, the invention is capable of use in other applications, in particular, other suspension applications, and the sway bar assembly as shown and described in merely shown and described as an example of one such application. For example, the fastener of the present invention could be used in combination with a strut assembly, an axle assembly, or various other assemblies found within vehicles to name just a few. It should also be understood that the fastener may be employed with various washers, bushings, or other mechanisms necessary to effect a secure connection without exceeding the scope of the present invention. 
   Thus, it should be understood that the invention is not limited in its application to the details of construction and arrangements of the components set forth herein. The invention is capable of other embodiments and of being practiced or carried out in various ways. Variations and modifications of the foregoing are within the scope of the present invention. It also being understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. 
   Various features of the invention are set forth in the following claims.