Abstract:
An adjustable clip for flexible flat cables comprising a pair of pivotally interconnected scissors arms having retainer tabs on the opposite ends and detents so that angle between the arms can be set in any of several different positions to accommodate FFCs of different widths. A bayonet fastener extends through a center hub portion so as to be forcibly inserted into a preformed hole in a support structure such as an automotive body pillar.

Description:
FIELD OF THE INVENTION 
   This invention relates to cable anchors, often called “clips,” for securing flexible flat cables to structural support members by means of bayonet fasteners and particularly to a device of the type described which is adjustable for receiving and securing flexible flat cables of different widths. 
   BACKGROUND OF THE INVENTION 
   It is known to anchor wiring harnesses to automotive body structures by means of clips which include a first portion which surrounds or otherwise attaches to the harness and a second portion such as a bayonet fastener which can be forced into a preformed hole in the body structure. The bayonet fastener is often called a “Christmas tree,” is made of plastic, and can take any of several forms all of which include barbs which deform to enter the hole and resist being withdrawn. 
   It is now becoming common to use flexible flat cables (“FFCs”) instead of more conventional bundled wires. An FFC is illustrated herein as comprising a plurality of parallel spaced apart flat conductors embedded in a flexible, plastic insulator. 
   The prior art shows one FFC anchor in the form of a flexible C-shaped plastic clip having an integral bayonet fastener extending from the clip base. An anchor of this design can only be used with an FFC having a width corresponding generally to the inside dimension of the C-shaped clip. Where FFCs of different widths are used, supplies of several different size anchors must be provided. 
   Adjustable clip-type anchors to accommodate FFCs of different widths are known. In general, such devices comprise multi-component ratchet or strap-type structures which are complex to make and use. 
   SUMMARY OF THE INVENTION 
   The present invention is a clip-type anchor for securing FFCs to support structures having one or more preformed holes by means of a bayonet fastener which can be inserted into the hole and retained by the structure after insertion. The device of the present invention accommodates FFCs of different widths, yet is simple and economical to both make and use. 
   In general, the present invention comprises a clip-type fastener device having first and second pivotally connected arms to form a scissors-type structure with retainer tabs at the ends. Using the scissors-action, the ends of the arms can be spread to receive the FFC and then closed to a degree to hold the FFC in place. A bayonet fastener projecting outwardly from the assembled arms is designed to be forced into a preformed hole to hold the FFC and clip in a desired location. 
   In the preferred embodiment, the lower arm has a central recess and the upper arm is shaped to fit into the recess such that the top surfaces of the two arms are essentially coplanar. The arms are provided with complemental bearing structures which can be snapped together to provide not only the pivotal scissors action, but also a mechanical retention which holds the two arms together. The bayonet fastener preferably extends through the center of the two arms and is held in position by a head and directional barbs on a shaft extending from the head. In this fashion, it is not necessary for the bayonet fastener to extend through the FFC and take up space which might otherwise be devoted to conductive material. 
   The components of the present invention are preferably formed by injection molding a suitable plastic such as Nylon to afford a measure of pliability. Means such as detents may be provided for releasably retaining the arms in one or more angular relationships to accommodate FFCs of predetermined widths. 
   Other features and advantages of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
       FIG. 1  is an exploded perspective view of an adjustable FFC anchor embodying the present invention; 
       FIG. 2  is an exploded sectional view of the components of the device of  FIG. 1 ; and 
       FIG. 3  is a perspective view of the device of  FIGS. 1 and 2  after assembly of the fastener to an FFC but before inserting the bayonet fastener into a preformed hole in an automotive body structure. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the figures, the anchor  10  of the present invention is shown to comprise a pair of injection molded plastic arms  12  and  14  which are preferably but not necessarily of equal length. The lower arm  12  has a circular central portion  16  carrying a raised cylindrical bearing structure  18  with an enlarged annular retainer ring  20  formed thereon. A central hole  22  defining an axis of rotation extends through the structure  18  to receive a barbed fastener  60 . The portion  16  has a recessed surface  24  which lies below surfaces  37  and  39  and which is planar except for the bearing structure  18  and a plurality of arcuately arranged raised detents  26  for purposes to be described. 
   The lower arm  12  has opposite ends  28  and  30  with raised retainer tabs  32  and  34  having oppositely extending tab arms  36  and  38 , respectively. The under surfaces of the arms  36 ,  38  are spaced above planar arm surfaces  37  and  39  by the thickness of an FFC  66  (shown in  FIG. 3  only), which is to be anchored by the device  10 . Through-holes  40  and  42  are provided in the tab structures  32  and  34  and arms  36  and  38  for purposes to be described. 
   The upper aim  14  is provided with a circular central portion  40  having through-hole  43  which is dimensional to complementary receive the bearing structure  18  of the lower arm  12 . The hole  43  is provided with an enlarged diameter annular portion  44  (shown in  FIG. 2  only) to receive the annular retainer ring  20  of the lower arm  12  in a snap-lock fashion to hold the two arms  12  and  14  together in a pivotal scissors-type relationship that allows changes in the angular relationship between the two arms  12  and  24  for purposes to be described. 
   The under surface of the central portion  40  of the upper arm is provided with recesses  72  which cooperate with the detents  26  to permit the arms  12  and  14  to be releasably retained in each of three different angular relationships corresponding to three different FFC widths. 
   When assembled, the top surface  41  of the upper arm  14  is essentially coplanar with the surfaces  37  and  39  of the lower arm  12 . The height d3 of the bearing  18  is equal to the thickness of the arm  14  as shown in FIG.  2 . 
   The upper arm  14  also has opposite ends at which are provided retainer tabs  48  and  50  with oppositely extending fingers  52  and  54  to receive and hold an FFC as shown in FIG.  3 . Holes  56  and  58  are formed in the retainer tabs  48  and  50  and arms for purposes to be described. 
   The anchor  10  is completed by means of a bayonet fastener  60  having an enlarged flat head  62  and a series of unidirectional barbs  64  which relatively easily enter a hole but resist withdrawal. The device  60  is of conventional construction, is often referred to as a “Christmas tree.” The length d1 between the under surface of the head  62  and the top of the first barb  64  is approximately equal to the dimension d2 of the arm  12  as shown in FIG.  2 . 
   The assembled condition is shown in FIG.  3 . The arms  12 ,  14  are snapped together and the fastener  60  is pushed through the center hole  22 . An FFC  66  is inserted into the anchor  10  by spreading the opposite ends of the arms  12 ,  14  sufficiently to permit insertion of the FFC  66  onto the surfaces  37 ,  39  and  41  and under the lateral extensions  36 ,  38 ,  52  and  54  of the retainer tabs. The arms  12 ,  14  are squeezed together to grip the FFC  66 . The barbs  64  are thereafter forcibly inserted into and through hole  68  which is formed in the automotive body structure  70  to hold the FFC  66  and the anchor  10  in the desired position. 
   The width of the FFC  66  corresponds to the distance between the opposite ends of the arms  12  and  14  when in one of the positions corresponding to the locations of the detents  26  on the lower arm  12  and the recess  72  in the undersurface of the upper arm  14  as shown in FIG.  2 . Indicia may be molded into or otherwise formed on the visible upper surfaces of the arms  12  and  14  as shown in  FIG. 1  to indicate to the user which FFC width is in use. 
   Various modifications and additions to the illustrated structures are possible. By way of example, the arm  12  may be made slightly longer than the arm  14  to cause the inwardly extending retainer tabs  38  and  54  to pass over and under one another to prevent interference. The retainer tab fingers may alternatively be angled differently, as shown, to achieve the same result. Also, by way of example, the bayonet fastener  60  may be formed integrally with the lower arm  14 . Additional bayonet fasteners may be used in connection with the holes  40 ,  42 ,  56  and  58  formed in the retainer tab structure at the ends of the arms  12 ,  14  if additional security in the anchoring of the assembly to a body structure or the like is necessary and available. 
   While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.