Patent Publication Number: US-2005120667-A1

Title: Captive fastener

Description:
FIELD OF INVENTION  
      This invention relates to a fastener for a floor panel adapted to be secured to a pedestal wherein the fastener is held captive in said floor panel.  
     BACKGROUND OF THE INVENTION  
      Elevated floor structures have gained much prominence with the advent of computer systems. Such elevated floor structure can consist of access floor panels elevated from the floor wherein the floor panels are in adjacent side-by-side relation in a rectangular array. Generally speaking, the panels are supported at their corners by spaced pedestals which in turn are supported on a sub-floor. Space between the sub-floor and floor panel is available for utility lines, air ducts, computer wire or the like. Generally speaking, the access floor panels are secured to the pedestal in a manner well known to those persons skilled in the art. The floor panels may be removed from the pedestals by unthreading the fasteners from the pedestals. However quite often when the access floor panels are removed the fasteners are lost, particularly when the panels are removed and turned upside down.  
      A variety of fastening means have heretofore been designed including those disclosed in U.S. Pat. Nos. 6,256,952, 5,862,643, and 5,749,616.  
      Moreover U.S. Pat. No. 5,546,717 teaches a self-threading pedestal screw which passes through a plastic insulator, then penetrating a pedestal screw passage. Finally U.S. Pat. No. 5,509,242 teaches fasteners to extend through the panel exterior and interior surfaces as disclosed.  
      It is an object of this invention to provide an improved fastener for floor panel to be secured to a pedestal whereby the fastener is held captive in the floor panel.  
      It is an aspect of this invention to provide a fastener for a floor panel adapted to be secured to a pedestal wherein the fastener is operable to move to a position to fasten the floor panel to the pedestal and a position to permit withdrawal of the floor panel from the pedestal while being captured by the floor panel.  
      It is another aspect of this invention to provide a fastening system adapted to be disposed in a hole of a floor panel for securing the floor panel to a pedestal comprising a sleeve having an axial length and adapted to be retained in the hole; a fastener co axially disposed in the sleeve and axially displaceable relative said sleeve between a first and second position, the fastener including a head at one end and a threaded end axially displaced from the head for threaded engagement with the pedestal when securing the floor panel to the pedestal in a first position; the sleeve including structure for inhibiting the fastener from being removed from the sleeve when the panel is removed from the pedestal in a second position.  
      These and other objects and features shall now be described in relation to the following drawings: 
    
    
     DRAWINGS  
       FIG. 1  is a cross-sectional view through a corner of an access floor panel showing the fastening system.  
       FIG. 2  is a top plain view of the sleeve of  FIG. 1 .  
       FIG. 3  is a partially enlarged view of a finger shown in  FIG. 1 .  
       FIG. 4  is a side elevational view of the fastener.  
       FIG. 5  is a view of another embodiment of the invention.  
       FIG. 6  illustrates a third embodiment of the invention.  
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Like parts have been numbered with like numbers throughout the figures.  
       FIG. 1  illustrates generally a floor panel  2  having a top surface  4  and a bottom surface  6  spaced from the top surface  4 . A fastener  10  is shown. The fastener  10  has a head  12  at one end and a threaded end  14  axially displaced from the head  12  for threaded engagement with a pedestal (not shown) in a manner well known to those persons well skilled in the art. The threaded end  14  has an exterior male thread  16  adapted to be received by a female interior thread presented by a pedestal (not shown). The fastener  10  also includes a shank portion  18  which has a diameter less than the threaded end  14 . The threaded end  14  may be bevelled to assist in aligning the fastener.  
      The fastener  10  is adapted to be secured to the pedestal (not shown) wherein the fastener  10  is operable to move to a first or secured position to fasten the floor panel  2  to the pedestal and a second or withdrawn position to permit withdrawal of the floor panel  2  from the pedestal (not shown) while being captured by the floor panel. In other words, when the fastener  10  is unthreaded from the pedestal (not shown) the floor panel  2  can be removed.  
      The floor panel  2  presents means  30  to restrain the threaded end  14  from being removed from the floor panel when the floor panel  2  is withdrawn from the pedestal. The restraining means  30  comprises in one embodiment a sleeve  40  adapted to be disposed in a hole  42  presented in the floor panel  2 . In particular the hole  42  extends from the top surface  4  to the bottom surface  6 . The hole  42  frictionally receives the sleeve  30 . Furthermore the hole  42  may include a chamfered portion  44  to accommodate the bevelled edge  20  of the fastener  10 .  
      In one embodiment the retaining means  30  comprises sleeve  40  which includes means for inhibiting  50  the threaded end  14  from being removed from the sleeve when the floor panel  2  is removed from the pedestal even if the floor panel is moved upside down.  
      The sleeve  40  has an axial length and is adapted to be retained in the hole  42 . The fastener  10  is co-axially disposed in the sleeve  10  and axially displaceable relative the sleeve  40  between said first position and said second position.  
      The fastener  10  is captive in the sleeve  40 . The fastener  10  can be installed into the sleeve  40  by pressing the fastener  10  past the inhibiting means  50 . In particular, in one embodiment shown in  FIGS. 1, 2  and  3 , the inhibiting means  50  comprise a spring or fingers extending into the sleeve where the fingers  52  are: 
          (a) displaceable radially outwardly to permit passage of the threaded end  14  past the fingers  52 ; and     (b) inhibit removal of the fastener  10  from the sleeve  40  by presenting a barrier to the threaded end  14  in a second position.        

      The shank portion  18  is axially displaceable in the sleeve  40  without contacting the fingers  52  when the fastener  10  is moved between the first position or when the threaded end  14  is secured to the pedestal and a second position when the floor panel is removed from the pedestals, and the fastener  10  moves to a position where the threaded end  14  is blocked by the fingers  52 .  
      More specifically the sleeve  40  presents an inner cylindrical surface  33  which presents a plurality of fingers  52  protruding from the surface towards the axis A. In the embodiment shown in  FIG. 2  four fingers  52  are present. However any number of fingers can be used within the spirit of this invention. The fingers  52  permit axial movement of the shank between the first and second positions, but present a barrier to the treaded end in the second position.  
      Furthermore the sleeve  40  presents a first end  35  adjacent to top surface  4  and a second end  37  adjacent the bottom surface  6 . The shank portion  18  has an axial length to permit the head  12  to engage the top surface of the floor panel in the second secured position whereby the bevelled edge  10  contacts the chamfered portion  44  where the top of the head  10  is flush with the top surface  4 . Furthermore the threaded portion  16  has an axial length less than the axial length between the second end  37  of the sleeve  30  and the plurality of fingers  52  so as to permit a threaded end  14  to be received in the sleeve  30 .  
      In this fashion the fastener  10  floats freely in a vertical motion or in other words is axially displaceable between the first and second positions so as to allow the panel to be laid flat on a surface. When the floor panel  2  is laid flat the fastener  10  protracts upwardly. Furthermore when the panel  10  is lifted to be put back into the floor the fasteners  10  will drop down by gravity. Moreover the captive fastener  10  and in particular the head  12  does not drop below the top surface  4  or into the hole  42  of the panel and thus can not get caught inside the panel  2 .  
      The fastener  10  may be of a self-threading type in a manner well known to those persons skilled in the art. Moreover the fastener  10  has a threaded portion  14  which is long enough to engage the female threaded portion of the pedestal as previously described. Furthermore the length of the shank  18  extending between the threaded portion  14  and at  16  may have a dimension less than the distance between the second end  37  of the sleeve and the fingers  52  as represented by the letter “H”. Furthermore the diameter of the head  12  is greater than the diameter of the hole  42 .  
      In one embodiment the sleeve is comprised of plastic. The sleeve  40  can be pressed into the access floor panel  2 . The plastic sleeve  40  has an inside diameter greater than the outside diameter of the threaded portion  14  of the fastener  10 .  
      The inside of the sleeve can present the four fingers  52  shown or alternatively protrusions or bumps which have an opening between them of less than the outside diameter of the threaded portion  16  of the fastener  10  but less than the outside diameter of the shank portion  18 .  
      The springs or bumps  50  in one embodiment are located at a distance from the bottom  37  of the sleeve  40  greater than the length of the threaded portion  14  of the fastener  10 .  
      The sleeve can comprise a variety of materials including nylon, plastic or metal. Furthermore the sleeve  40  may act as a plug to prevent leakage from within the cavity  16  of the access floor panel  2  to prevent leakage when the panel is filled with cement, foam or other material.  
       FIG. 5  illustrates another embodiment of the invention whereby the fastener  10  is captive within the sleeve  40 . In particular the sleeve  40  includes a plastic cylinder  70  which has internal threads  72 . The outside diameter of the plastic cylinder  70  has a press fit or frictioned fit with the inside surface  33  of the cylinder  30 . Alternatively the cylinder  70  can be glued or integrally formed.  
      Accordingly the inhibiting means shown in  FIG. 5  consists of female threaded portion  72  which permits rotational passage of the threaded end of the fastener  10  through the female threaded portion  72  but inhibits axial removal of the fastener  10  in a second position, i.e., when the access floor panel  2  is removed from the pedestal. It should be noted that the plastic cylinder can be comprised of a variety of materials other than a plastic, such as nylon, metal, or the like.  
      In another arrangement as shown in  FIG. 6  the fastening system has an inhibiting means which comprises protrusions  86  disposed interiorally of the sleeve  40  to: 
          (a) permit forced passage of the threaded end  14  past the protrusions  86  into the sleeve so as to permit the fastener  10  to be secured into the pedestal, and     (b) inhibit removal of the fastener  10  from the sleeve  40  and the access floor panel  2  by presenting a barrier to the threaded end  14  in a second or removed position.        

      In particular the fastener system illustrated in  FIG. 6  illustrates a fastener  10  which includes a shank portion  18  intermediate to head  12  and threaded portion  14  where the shank portion  18 , has a diameter less than the threaded portion  14 , a shoulder  82  presented by the shank  18  and a ring  84  which is axially displaceable relative to shank  18  between the shoulder  82  and the threaded end  14 .  
      The sleeve  40  includes means  86  for catching the ring  84  so as to allow the fastener  12  to move between the first and second positions. The catching means  86  comprises of two spaced, centric, annular protrusions adapted to catch the ring  84  there between. Moreover the two protrusions  86  define a groove  87  therebetween.  
      The fingers  52  illustrated in  FIG. 3  may be substituted with protrusions  86  which are dimensioned so as to permit the fastener  12  to be pushed past the protrusions when moving the fastener  12  to the first secured position but which present a barrier when the access floor panel is removed therefrom, to prevent the fastener from being easily removed from the sleeve  40 .  
      Although the preferred embodiment as well as the operation in use have been specifically described in relation to the drawings, it should be understood the variations in the preferred embodiment could be achieved by a person skilled in the trade without departing from the spirit of the invention as claimed herein.