Abstract:
A captive panel fastener has a telescopically adjustable two-part sleeve which provides a mechanism whereby the length of the fastener is selectively adjustable.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to fasteners and, more particularly, to a fastener which is secured to a panel and is adapted to mount the panel to an underlying chassis. 
     Captive panel fasteners are used on a wide variety of products. Commercially available captive panel fasteners typically come in standard, pre-specified lengths which are dictated by the manufacturer and the demand for the product. Typically, the manufacturer stocks a number of fasteners which usually differ by length and thread code. This forces the manufacturer to stock many different types of fasteners, thereby increasing inventory costs. Also, when a non-standard length is required for a specific application, no product is available to address the application. It would therefore be desirable to have an adjustable length captive panel fastener. 
     SUMMARY OF THE INVENTION 
     According to the present invention, a captive panel fastener has a telescopically adjustable two-part sleeve which provides a mechanism whereby the length of the fastener is selectively adjustable. 
     According to an aspect of the present invention, there is provided an adjustable length captive panel fastener which comprises a cylindrical sleeve member having an internal axial through-bore. The sleeve member is formed with attachment structure at one end to secure the fastener to a panel. An adjustment member is axially movable within the sleeve member from the end opposite the one end, and has an internal axial through-bore which is stepped so as to provide first and second spaced ledges. A headed screw is adapted to extend through the internal through-bores of the sleeve member and the adjustment member so as to be rotatable and axially movable therein. The head of the screw is dimensioned so as not to pass the first ledge. A coil spring surrounds the screw within the through-bore of the adjustment member. A first end of the spring abuts the head of the screw and the second end of the spring abuts the second ledge. 
     In accordance with another aspect of this invention, the sleeve member is formed with internal threads in its through-bore and the adjustment member is formed with external threads adapted to mate with the internal threads of the sleeve member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing will be more readily apparent upon reading the following description in conjunction with the drawing in which the single FIGURE thereof is a cross-sectional view showing an adjustable length captive panel fastener constructed in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawing, the adjustable length captive panel fastener according to the present invention, designated generally by the reference numeral  10 , includes a cylindrical sleeve member  12  which has an internal axial through-bore  14 . At a first end  16 , the sleeve member  12  is formed with attachment structure  18  for securing the fastener  10  to a panel  20 . Illustratively, the attachment structure  18  is a radially outwardly directed flange surrounding the through-bore  14  at the first end  16  of the sleeve member  12 . The flange  18  is adapted to extend through an aperture  22  in the panel  20  to secure the fastener  10  to the panel  20  by a press-fit operation with the through-bore  14  aligned with the aperture  22 . 
     The fastener  10  also includes adjustment member  24  which is externally threaded at  26  to mate with complementary threads  28  in the through-bore  14  of the sleeve member  12 . The threads  28  extend into the through-bore  14  from the second end  30  of the sleeve member  12  so that the adjustment member  24  is axially movable within the sleeve member  12 . The adjustment member  24  has a radially outwardly directed flange  32  adapted to abut the end  30  of the sleeve member  12  so as to provide a limit for insertion of the adjustment member  24  into the through-bore  14  of the sleeve member  12 . Thus, the sleeve member  12  and the adjustment member  24  are telescopically adjustable to selectively vary the length of the fastener  10 . 
     The adjustment member  24  is formed with an internal axial through-bore  34  which is stepped so as to provide a first ledge  36  and a second ledge  38 . A headed screw  40  extends through the through-bores  14  and  34 . The head  42  of the screw  40  is sized so that it cannot pass the first ledge  36 . 
     A coil spring  44  surrounds the screw  40  within the through-bore  34  of the adjustment member  24 . A first end of the spring  44  abuts the head  42  of the screw  40  and the second end of the spring  44  abuts the second ledge  38 . A retainer ring  46  captures the screw  40  so as to keep the assembly together. 
     In use, when the panel  20  is to be secured to an underlying chassis (not shown), the threaded end of the screw  40  is inserted into a suitable threaded bore in the chassis. The screw  40  is then rotated against the biasing force of the spring  44  until the head  42  bottoms out against the first ledge  36 . If the threaded end of the screw  40  bottoms out in the threaded bore of the chassis before the head bottoms against the ledge  36 , this indicates that the fastener  10  is too short. In this case, the adjustment member  24  is backed out of the sleeve member  12  a sufficient distance so that the screw head  42  bottoms out against the first ledge  36  before the threaded end of the screw  40  bottoms out in the threaded bore of the chassis. 
     Accordingly, there has been disclosed an improved adjustable length captive panel fastener. While an illustrative embodiment of the present invention has been disclosed herein, it will be appreciated by those of skill in the art that various adaptations and modifications to the disclosed embodiment are possible. It is therefore intended that this invention be limited only by the scope of the appended claims.