Abstract:
A captive fastener assembly and method comprising a retaining plate for positioning upon a perimeteral surface of a cover of an enclosure during use, the retaining plate comprising a plurality of plate openings having an inner diameter for the passage of a plurality of respective captive fasteners. The captive fastener assembly further comprises a plurality of respective securing rings having inner and outer diameters, the plurality of capture fasteners comprising an annular notch for fixedly attaching to the inner diameter of the securing ring during use, wherein the outer diameter of the securing rings is greater than the inner diameter of the plate openings.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/977,367 filed Apr. 9, 2014 entitled CAPTIVE FASTENER ASSEMBLY AND METHOD. The above-identified provisional application is incorporated herein by reference in its entirety for all purposes. 
     
    
     FIELD OF THIS DISCLOSURE  
       [0002]    The present disclosure relates to a captive fastener assembly method and more specifically, a captive fastener assembly and method for securing first and second portions of a cover to form a single enclosure with one more fasteners, while retaining said fasteners to the enclosure should any one of the fasteners become disengaged. 
       BACKGROUND 
       [0003]    Captivating bolts has advantages such that it prevents bolts from being lost or displaced when conditions allow the bolts to become loose or disengaged. This is particularly important when the bolts could become displaced into moving equipment, such as motors and the like. 
         [0004]    One known method for captivating bolts is by using a non-metallic insert. This insert is held in a counter bore on the inside of the cover. The bolt then threads through the insert. The insert holds the bolt in place in the cover. Generally, one problem with this method is that it is often difficult to thread the bolt through the insert. As a result, damage can occur to the cover from the use of too much force to tighten the bolts. Another problem that can arise with this method is that it is often relatively easy to unthread the bolt all of the way out of the insert. This results in loss of the captivation of the bolt. Additionally, over time, wear on the insert can result in the loss of captivity of the bolt. 
         [0005]    While another method for captivating bolts is the use a reduced shank bolt. In this method, the cover has specially machined holes that have a few threads near the outside surface of the cover and a larger counter bore on the inside surface of the cover. As the reduced shank bolt is unthreaded, the threaded portion of the bolt is retained against the threaded portion of the cover. One problem that may occur with this method is that in addition to a specially made bolt, a specially made cover is also required. While another problem that can occur with this design is that the bolt can bind against the threads in the cover when the bolt is being unthreaded. 
       SUMMARY 
       [0006]    One aspect of the present disclosure comprises captive fastener assembly and method comprising a retaining plate for positioning upon a perimeteral surface of a cover of an enclosure during use, the retaining plate comprising a plurality of plate openings having an inner diameter for the passage of a plurality of respective captive fasteners. The captive fastener assembly further comprises a plurality of respective securing rings having inner and outer diameters, the plurality of captive fasteners comprising an annular notch for fixedly attaching to the inner diameter of the securing ring during use, wherein the outer diameter of the securing rings is greater than the inner diameter of the plate openings. 
         [0007]    Another aspect of the present disclosure comprises a method of securing first and second cover portions together to form an enclosure with a captive fastener assembly in order to retain a plurality of captive fasteners to the enclosure should any one of a plurality of captive fasteners become disengaged from the first or second cover portions, the method comprising the steps of: securing a retaining plate upon a perimeteral surface of a first cover of an enclosure during use, the retaining plate further comprising a plurality of plate openings having an inner diameter for the passage of a plurality of respective captive fasteners; providing a plurality of respective securing rings having inner and outer diameters, the plurality of captive fasteners comprising an annular notch for fixedly attaching to the inner diameter of the securing ring during use; and providing the outer diameter of the securing rings to have a greater diameter than the inner diameter of the plate openings such that the retaining plate retains the plurality of fasteners to the enclosure should any one of the plurality of fasteners become disengaged from the first and second cover portions. 
         [0008]    While another aspect of the present disclosure includes an enclosure system having captive fastener assembly for securing a plurality of fasteners to an enclosure, the enclosure system comprising: first and second cover portions that when secured together by at least two captive fasteners form an enclosure, one of the first and second cover portions having a plurality of threaded openings and the other of the first and second cover portions having a plurality of pass-through openings, the pass-through openings being substantially concentrically aligned with the threaded openings in order to receive the at least two captive fasteners; a captive fastener assembly comprising: the at least two captive fasteners; a retaining plate for positioning upon a perimeteral surface the cover portion comprising the pass through openings, the retaining plate further comprising a plurality of plate openings having an inner diameter for the passage of the at least two fasteners; and a respective securing ring for fixedly attaching to each of the at least two captive fasteners, the securing rings having inner and outer diameters and the at least two captive fasteners comprising an annular notch for fixedly attaching to the inner diameter of the securing ring during use, wherein the outer diameter of the securing rings is greater than the inner diameter of the plate openings, such that the retaining plate retains the securing ring; and fixedly attached captive fasteners within the pass through-opening should any one of the captive fasteners become unthreaded from the threaded openings. 
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       [0009]    The foregoing and other features and advantages of the present disclosure will become apparent to one skilled in the art to which the present disclosure relates upon consideration of the following description of the disclosure with reference to the accompanying drawings, wherein like reference numerals, unless otherwise described refer to like parts throughout the drawings and in which: 
         [0010]      FIG. 1 . is a first perspective view of an enclosure arrangement comprising a captive fastener assembly constructed in accordance with one example embodiment of the present disclosure; 
         [0011]      FIG. 2  is a second perspective view of  FIG. 1 ; 
         [0012]      FIG. 3  is a top plan view of  FIG. 1 ; 
         [0013]      FIG. 4  is a bottom plan view of  FIG. 1 ; 
         [0014]      FIG. 5  is a lower front elevation view of  FIG. 1 ; 
         [0015]      FIG. 6  is an upper front elevation view of  FIG. 1 ; 
         [0016]      FIG. 7  is a first side elevation view of  FIG. 1 ; 
         [0017]      FIG. 8  is a second side elevation view of  FIG. 1 ; 
         [0018]      FIG. 9  is an exploded perspective assembly view of  FIG. 1 ; 
         [0019]      FIG. 10  is a partial perspective section assembly view of an enclosure arrangement comprising a captive fastener assembly constructed in accordance with another example embodiment of the present disclosure along section lines  10 - 10  and  11 - 11  in  FIG. 3   
         [0020]      FIG. 11  is a further partial perspective section assembly view of the enclosure arrangement comprising a captive fastener assembly of  FIG. 10 ; 
         [0021]      FIG. 12A  illustrates a first step of a method of assembly of a captive fastener assembly in accordance with one example embodiment of the present disclosure; 
         [0022]      FIG. 12B  illustrates a second step of the method of assembly of  FIG. 12A ; and 
         [0023]      FIG. 12C  illustrates a third step of the method of assembly of  FIG. 12A . 
     
    
       [0024]    Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present disclosure. 
         [0025]    The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
       DETAILED DESCRIPTION 
       [0026]    Referring now to the figures generally wherein like numbered features shown therein refer to like elements having similar characteristics and operational properties throughout unless otherwise noted. The present disclosure relates to a captive fastener assembly method and more specifically, a captive fastener assembly and method for securing first and second portions of a cover to form an enclosure arrangement with one more fasteners, while retaining said fasteners to the enclosure arrangement should any one of the fasteners become disengaged. 
         [0027]    Referring now to  FIGS. 1-12C , an enclosure arrangement  10  secured together with a captive fastener assembly  12 . The enclosure arrangement  10  comprises first and second boxes or covers  14 ,  16 , respectively. In one example embodiment, the enclosure arrangement  10  is a metal explosion proof and/or a dust tight enclosure made by Adalet, a Scott Fetzer Company and an assignee of the present disclosure. In another example embodiment, the enclosure  10  can be any type of container, case, trunk, or the like when it is desirable for the fasteners remain coupled to the enclosure. 
         [0028]    In one example embodiment, the covers  14  and  16  are made from metal, such as aluminum or stainless steel. The second cover  16  includes a base  18  with a plurality of tabs  20  for supporting the enclosure arrangement  10  to a surface such as a wall or floor with the use of fasteners as would be appreciated by one of ordinary skill in the art. Located and concealed during use between first and second covers  14 ,  16 , is a cavity  22  (see  FIG. 10 ) for housing motors, machines, and in the like. 
         [0029]    Surrounding the perimeter of the first and second covers  14 ,  16  are respective first and second flanges  24 ,  26 . The flanges  24 ,  26  support the captive fastener assembly  12 . That is, the flanges include corresponding openings  28  for securing the first cover  14  to the second cover  16  via a plurality of fasteners  30 . In one example embodiment, the fasteners are bolts, such as socket head cap screws, standard and quad lead bolts, or hex head bolts, that may include a shoulder or an unthreaded portion. The fasteners  30  in one example embodiment further comprise a head or cap  31  at a first end and a plurality of threads  33  at a second end. 
         [0030]    The openings  28  include an oversized opening  28 A through the first cover  14 , which is oversized for the passage of the fastener  30 , such as a drill through or counter-bored opening. While the openings  28 B in the second cover are tapped-through openings for receiving the threaded portion of the fasteners  30 . 
         [0031]    The captive fastener assembly  12  comprises a retaining plate  40  that surrounds the perimeter  15  of the first cover  14  along the first flange as illustrated in  FIGS. 1 and 9 . The retaining plate  40  includes corresponding openings  28  for the passages of the fasteners  30 . In particular, the corresponding openings  28  forming the retaining openings  28 C are spaced and correspond with the openings  28 A and  28 B in the first and second covers,  14  and  16 , respectively. In one example embodiment, the retaining plate  40  is made of metal, such as, for example aluminum or stainless steel. 
         [0032]    In the illustrated example embodiment, the retaining opening  28 C diameter is smaller than the diameter of the first cover  14  opening  28 A, but are slightly large enough to allow for the unrestrictive passage of the fastener  30  therethrough. The captive fastener assembly  12  further comprises modified fasteners  30  that include an annular notch  42 . In one example embodiment, the annular notch  42  is an under-cut machined or turned into the fastener by a lathe. In one example embodiment, the notch  42  diameter of 0.4130+/−0.003 inches for a half-inch diameter size fastener  30 . 
         [0033]    Also forming part of the captive fastener assembly  12  are securing rings  44 . A securing ring  44  is positioned during assembly into each notch  42  of the fasteners  30 . The securing ring  44  in one example embodiment is made from metal, such as stainless steel and has an outer diameter of 0.523+/−0.003 inches for securing into the 0.4130 inch diameter notch  42  in the example embodiment discussed above. In one example embodiment, the securing ring  44  is continuous, while in another example embodiment, the securing ring is a snap ring having an opening  46  (see  FIGS. 9 and 12 ) to allow the ring to be snapped and held into the notch  42 . 
         [0034]    The captive fastener assembly  12 , and more specifically the retaining plate  40  includes a plurality of holding points  48 . The holding points  48  include in one example embodiment, a through hole  50  in the retaining plate  40  and a holding fastener  52  that corresponds to a tapped hole  54  in the first cover  14  beneath the retaining plate. The holding points  48  secure the retaining plate  40  to the perimeteral  15  surface of the first cover  14 . In another example embodiment, the holding points  48  comprise a self tapping fastener  52 , eliminating the need for a pre-drilled through hole  50  and tapped hole  54 . 
         [0035]    Referring now to  FIGS. 10 ,  11 ,  12 A,  12 B, and  12 C, is a method of installing a captive fastener assembly  12  on an enclosure arrangement  10  in accordance with one example embodiment of the present disclosure. 
         [0036]    In the illustrated example embodiment, the fasteners  30  are first inserted first into openings  28 C in the retaining plate  40  before the securing rings  44  are attached to the fasteners  30  about their respective notches  42  (either by a snap ring through opening  46  or by being placed about the fastener from the bottom up into the notch). The fasteners  30  are then placed into openings  28 A of the first cover  14  and threaded into tapped openings  28 B of the second cover  16 . 
         [0037]    The retaining plate  40  is then secured to the perimeteral surface of the first cover  14  by holding points  48 . The securing rings  44  have an outer diameter smaller than the diameter of the opening or c&#39;bore  28 A, thus allowing free movement of the fastener  30  therein during the threading of the fasteners to the tapped opening  28 B. 
         [0038]    The securing rings  44 , however, have an outer diameter that is larger than the diametrical opening  28 C in the retaining plate  40 . Thus, once the retaining plate  40  is secured to the first cover  14  by the holding points  48 , the retaining plate and its small opening  28 C prevent the passage of the securing ring  44  or their corresponding fasteners  30  from the openings  28 . As such, should a fastener  30  become unthreaded from the tapped opening  28 B, the captive fastener assembly  12 , namely the retaining plate  40  and securing rings  44  prevent the fastener from leaving the opening  28 , since the securing rings&#39; diameter is larger, thus the securing rings&#39; outer diameter is blocked by the smaller diameter of the corresponding openings  28 C in the retaining plate. 
         [0039]    The above construction and method of installation of the captive fastener assembly  12  advantageously allows numerous types of covers  10  to be used with this fastener securing design. Moreover, such design of the captive fastener assembly  12  provides for retro fitting existing covers and enclosure arrangements  10 . 
         [0040]    In the foregoing specification, specific embodiments have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the disclosure as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present teachings. 
         [0041]    The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The disclosure is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued. 
         [0042]    Moreover in this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” “has”, “having,” “includes”, “including,” “contains”, “containing” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, has, includes, contains a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a”, “has . . . a”, “includes . . . a”, “contains . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises, has, includes, contains the element. The terms “a” and “an” are defined as one or more unless explicitly stated otherwise herein. The terms “substantially”, “essentially”, “approximately”, “about” or any other version thereof, are defined as being close to as understood by one of ordinary skill in the art, and in one non-limiting embodiment the term is defined to be within 10%, in another embodiment within 5%, in another embodiment within 1% and in another embodiment within 0.5%. The term “coupled” as used herein is defined as connected, although not necessarily directly and not necessarily mechanically. A device or structure that is “configured” in a certain way is configured in at least that way, but may also be configured in ways that are not listed. 
         [0043]    The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.