Abstract:
A device for captivating a variety of fasteners relative to a first member. A captivator includes a body adapted to be secured to the first member and a retainer received within the body and having a surface engaging a captured fastener. Together the body and retainer maintain the captivated fastener in place relative to the first member. Keyway surfaces are provided upon the body or retainer or both and an external or internal key engages the keyway surfaces to selectively lock the body and retainer together, such as during installation or replacement of the captured fastener. Upon removal of the key, the retainer is free to rotate and translate relative to the body.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 61/344,802, filed Oct. 13, 2010, and incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to fasteners, and more particularly, to a captive screw-type fastener assembly for securing together a pair of members, and where the fastener is retained in position on one of the members to be secured, when disconnected. 
     BACKGROUND OF THE INVENTION 
     Broadly, captive fastener assemblies are well known, including but not limited to a variety of captive screw devices. Many of these assemblies are relatively complex and consist of customized components. Reliability, ease of operation and overall efficiency of known fastener assemblies is often inadequate. For example, the screws used in many known fastener assemblies are custom machined components which add to costs and limit the applicability of a given assembly. Because of the customized nature of prior captive screw assemblies, a significant inventory of component parts is often required to accommodate different captive screw requirements. Furthermore, additional machinery and effort are ordinarily required to affix captive screw assemblies. Interchangeability of known assemblies has also been limited. Still further, many captive screw assemblies have inseparable components and field repair is difficult if not unfeasible. Often an entire panel or subassembly must be returned to a shop for repair or replacement when the captive screw is damaged. 
     Thus, a need remains for a screw captivator providing improved reliability, ease of operation, and overall efficiency. A need also exists for a system of screw captivators consisting of modular components and suitable for use with conventional threaded fasteners. 
     SUMMARY OF THE INVENTION 
     The present invention provides a screw captivator that is both simple and economical to manufacture, and readily installed and used. The captivator avoids extraneous parts and cumbersome connections. The present invention also provides a system of screw captivators utilizing modular components suitable for use with conventional threaded fasteners. In this manner, a system of relatively few components can captivate a vast array of screws or other threaded fasteners. A screw captivator of the present invention provides a simplified installation procedure and reduces the cost of the use of the captivators of this invention. 
     The present invention relates to a screw captivator useful, for example, to secure together a pair of members, such as panels. For example, in operation the panels are brought together with the bottom surface of the upper panel being flush with the top surface of the lower panel. Mounted upon the top surface of the upper panel is a captured screw with a threaded shaft of the screw capable of protruding beyond the bottom surface of the upper panel so as to engage a nut or other threaded aperture of the lower panel. By tightening the captive screw, the panels are secured together. 
     To use an example of a screw captivator of the present invention, the upper panel is prepared by drilling or punching a hole or slot of a selected diameter. A counter bore may be drilled or a dimple may be formed on the bottom side of the upper panel, to accommodate connection of a body to the upper panel. A threaded retainer is then passed into the body and is sized to engage the captive screw. A tool may be used to engage and lock the body and retainer together while the screw to be captured is threaded into the retainer. The tool may be an external, hand-graspable tool having a keyed end adapted to engage keyway surfaces of the body or retainer or both. Alternatively, either the body or retainer may incorporate a tool, such as a keyed surface, to engage a keyway and lock the body and retainer together while the captive screw is threaded into the retainer. A variety of different keys and keyways are disclosed herein. In one embodiment, the key is provided on the distal end of an external tool which is inserted into the body from the underside of the top panel. The tool includes a cylindrical receptacle for receiving a portion of the captive screw shaft during assembly. Once the retainer and captive screw are connected, the tool can be withdrawn to permit free rotation between the body and the retainer/captive screw. 
     One object of the invention is to provide a captivator capable of capturing a wide variety of common, conventional threaded fasteners. Another object of the invention is to provide a system of screw captivators which significantly reduces the number of component parts necessary to capture a wide variety of threaded fasteners. A significantly smaller inventory of component parts would be needed to accommodate a variety of threaded fasteners as compared to systems of the prior art. 
     Another object of the invention is to provide a captivator with a self-ejecting feature using an ejection spring. The ejection spring can be protected from hostile environments when the captive screw is fastened. 
     A further object of the invention is to provide a screw captivator which is simple, rugged, small in size and suitable for low-cost mass production. 
     Other purposes will appear in the ensuing specification, drawings and claims. The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings which form part of the specification and wherein like numerals and letters refer to like parts wherever they occur. 
         FIG. 1  is a perspective illustration of a pair of screw captivators in accordance with the present invention. 
         FIG. 2  is a cross-sectional view of the screw captivators of  FIG. 1 . 
         FIG. 3  is a perspective illustration of the screw captivators of  FIG. 1  shown in an extended or retracted orientation. 
         FIG. 4  is a cross-sectional view of the screw captivators of  FIG. 3 . 
         FIG. 5  is an exploded perspective view of the screw captivators of  FIG. 1   
         FIG. 6  is a plan view of a cap screw and cover suitable for use with the screw captivator of  FIG. 1 . 
         FIG. 7  is a cross-sectional view of the screw of  FIG. 6 . 
         FIG. 8  is a perspective view of a screw captivator utilizing the cap screw and cover of  FIG. 6 . 
         FIG. 9  is a cross-sectional view of the screw captivator of  FIG. 8 . 
         FIG. 10  is a cross-sectional view of a body component of the screw captivator of  FIG. 1 . 
         FIG. 11  is a perspective view of the body component of  FIG. 10 . 
         FIG. 12  is another perspective view of the body component of  FIG. 10 . 
         FIGS. 13 ,  14  and  15  are yet other perspective views of the body component of  FIG. 10 . 
         FIG. 16  is an exploded perspective view of the screw captivator of  FIG. 1  including an assembly tool. 
         FIG. 17  is a perspective view of the assembly tool of  FIG. 16  along with a retainer component of the screw captivator. 
         FIG. 18  is a cross-sectional view of a screw captivator and assembly tool as depicted during an assembly process. 
         FIG. 19  is a perspective view of the assembly tool, panel members and retainer components of the screw captivator of  FIG. 1 . 
         FIG. 20  is a cross-sectional view of the assembly tool, captive fastener, retainer and body components of the screw captivator of  FIG. 1 . 
         FIG. 21  is a perspective view of a captive screw, body and retainer components and assembly tool. 
         FIG. 22  is a perspective view of the body component of the screw captivator of  FIG. 1  and the assembly tool. 
         FIGS. 23 and 24  are perspective views of a second embodiment of the body and retainer components of a screw captivator in accordance with the present invention. 
         FIGS. 25 and 26  are perspective views of a third embodiment of the body and retainer components of a screw captivator in accordance with the present invention. 
         FIGS. 27 and 28  are perspective views of a third embodiment of the body and retainer components of a screw captivator in accordance with the present invention. 
         FIGS. 29 and 30  are perspective views of a fourth embodiment of the body and retainer components of a screw captivator in accordance with the present invention. 
         FIGS. 31 and 32  are perspective views of a fifth embodiment of the body and retainer components of a screw captivator in accordance with the present invention. 
         FIGS. 33 and 34  are perspective views of a sixth embodiment of the body and retainer components of a screw captivator in accordance with the present invention. 
         FIGS. 35 and 36  are perspective views of a seventh embodiment of the body and retainer components of a screw captivator in accordance with the present invention. 
         FIG. 37  is a perspective view of a screw captivator in accordance with the present invention. 
         FIG. 38  is a cross-sectional view taken through a body component of an alternative embodiment of a screw captivator. 
         FIG. 39  is a detailed view of  FIG. 38  depicting the connection between a base and retainer elements of the body component of  FIG. 38 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout, and prime notation is used to indicate similar elements in alternate embodiments. 
     Referring now to  FIG. 1 , two embodiments of the present invention are illustrated as screw captivators  10 ,  20  for securing together two elements, such as plate or panel members  30 ,  32 , via a captured screw  40 . The configuration of members  30 ,  32  may be widely varied and need not constitute plate members. The present invention can thus be adapted to secure together a wide variety of elements, such as plates, panels, frames, etc. For simplicity&#39;s sake member  30 ,  32  will simply be referred to as panels in this description. 
     In one application of the invention, panel  30  may be a removable panel and panel  32  may be a frame or body.  FIGS. 1 and 2  illustrate the screw captivators  10 ,  20  as connecting panels  30 ,  32 .  FIGS. 3 and 4  illustrate the screw captivators in retracted (non-connected) configurations. 
       FIG. 2  is a cross-sectional view of  FIG. 1 , where screw captivator  10  is a non-spring loaded assembly. In comparison, screw captivator  20  of  FIG. 3  includes a spring  22  which biases the captured screw  40  upwardly so as to retract a threaded end of the captive screw  40 . Depending on the length of the screw  40 , the threaded end of screw  40  may be fully retracted into the assembly  20 , thereby precluding scratching or damaging the underlying member  32 . When the threaded end of captive screw  40  is released from panel member  32  it is thus automatically retracted and can be made to entirely enter the body  21 . Such full retractability means that the panels  30 ,  32  can be essentially flush against each other prior to tightening down of the captive screw  40 . 
     Screw captivator  10  includes body  11 , retainer  12  and washer  13  (optional). For illustration purposes, captive screw  40  is shown as a simple hex-headed screw fastener adapted to engage a nut  14  of panel  32 . As described in detail hereinafter, captive screw  40  may assume a variety of shapes, size and configurations including non-headed fasteners, simple threaded shanks, handles, knobs, etc. 
     In this assembly, body  11  secures the captured screw  40  to panel member  30 . The retainer  12  is a cylindrical element having an outwardly projecting flange  16  at one end. This is for engagement with an inwardly extending flange  17  on the body  11  when the two parts are fitted together. In other words, when the retainer  12  is received into the body  11 , it can slide relative to the body  11 , but axial movement in one direction is limited by the flanges  16 ,  17 . 
     Body  11  may be secured to panel member  30  via welding, adhesive, mechanical deformation, etc., or may be freely disassociated from member  30 . In one embodiment, body  11  includes an end which is swaged to secure body  11  to member  30 . In another embodiment, body  11  can be secured to panel  30  via a floating connection. For example, body  11  can be secured so as to permit movement within an elongate slot. Body  11  could also be secured to panel  30  via a snap-fit structure, such as described herein with reference to  FIGS. 38 and 39 . 
     Retainer  12  captivates screw  40  within body  11 . As described in more detail hereinafter, when fitted together flange  16  of retainer  12  cooperates with flange  17  of body  11  to precludes screw  40  from detaching from body  11 . When screw  40  is retained by retainer  12 , it can move relative to the body  11 , but axial movement in one direction is limited by contact between flanges  16 ,  17  so as to prevent detachment. Flanges  16 ,  17  thus act to captivate the captive screw  40  while still allowing unrestricted rotation of the captive screw  40 . 
     Washer  13  is optional and provides a means for facilitating the rotation of the screw head relative to the body  11 . A variety of washer styles (e.g., split, configured, flat) could be utilized as dictated by a given application. 
     Panel nut  14  may be secured to the underside of panel member  32  via welding, adhesive, deformation, etc. or may be freely disassociated with member  32 . In alternative embodiments, panel nut  14  can be replaced with a simple aperture which need not even contain internal threads. For illustration purposes, panel nut  14  of  FIG. 2  simply provides an internally-threaded element which is engaged by the captive screw assembly  10  to secure the panels  30 ,  32  together. 
     The second embodiment of screw captivator  20  includes body  21 , spring  22 , cover  23 , retainer  12  and panel nut  14 . Body  21  may be secured to panel member  30  via welding, adhesive, deformation, etc. or may be freely disassociated from member  30 . In one embodiment, body  11  includes an end which is swaged to secure body  11  to member  30 . 
     Spring  22  biases the assembly to a retracted orientation as shown in  FIGS. 3 and 4 . One end of spring  22  engages a flange  24  on body  21  and the end of spring  22  engages the underside of cover  23 . In other embodiments, the spring  22  could engage the top surface of panel  30 . To promote a compact assembly, spring  22  is a helical coil having a diameter greater than the diameter of body  21 . 
     Cover  23  is a generally open ended cylinder functioning to shield debris and conceal spring  22  and also act as a flat wash for screw  40 . Cover  23  is optional and in embodiments not having cover  23 , spring  22  may engage the underside of screw  40  (or handle, knob, etc.) or be replaced by a flat washer. Cover  23  may include knurling or other surface texture or configurations. 
       FIG. 5  illustrates components of the screw captivator  10 ,  20  in an exploded perspective view. 
       FIGS. 6 through 9  illustrate another embodiment of cover  50  wherein a conventional socket head cap screw  52  is received within cover  50 . Cap screw  52  may be press-fit into engagement with cover  50  or be secured by adhesive. In another embodiment, cover  50  could be larger and form a hand-graspable knob. 
     Referring now to  FIGS. 10 and 11 , details of body  11  will be discussed. Body  11  is generally cylindrical in form and includes a first end  60  adapted to receive retainer  12 . Second end  62  includes flange structure  17  for engaging flange structure  16  of retainer  12  thereby limiting axial displacement of the retainer relative to body  11 . First end  60  may include an annular narrowing size to be received within a panel aperture. The first end  60  may be deformed, such as via a swaging process, to secure the body  11  to a panel. In other embodiments, body  11  may be welded or otherwise mechanically coupled to a panel. While body  11  is illustrated as a generally cylindrical form, alternative embodiments of body  11  could assume a variety of other forms. 
     A portion of body  11  defines keyway surfaces  64  which are engaged by a keyed tool as described hereinafter. The keyed tool is utilized during assembly/disassembly of the captive screw assembly  10 . A variety of different keyway surfaces may be provided upon body  11  as described herein with reference to  FIGS. 23 through 26 . 
     Referring now to  FIGS. 12 through 15 , retainer  12  is shown in various views. Retainer  12  is generally cylindrical in form and includes interior threading  70  and flange structure  16  at one end. Interior threading  70  is adapted to engage threading on the screw  40  to be captured. The interior threading  70  need to extend the full length of retainer  12 . Various thread sizes, pitches and configurations are envisioned for a family of retainers  12  to accommodate various screw sizes and pitches. In addition, the upper end of the retainer  12  may be relieved to allow the retainer to thread up a screw  40  that is not fully threaded. Also, the upper end of the retainer  12  may have external relief so that a standard flat washer may slide over it. Retainer  12  is sized for axial movement within body  11  with flange structure  16  preventing detachment of retainer  12  from body  11 . 
     The connection between retainer  12  and captive screw  40  may be further secured with an adhesive, such as a thread locking compound, to inhibit loosening. In another embodiment, retainer  12  may include other thread-locking structures such as a deformable polymer tip, asymmetric threading, lock washers, etc. In one embodiment, the end of retainer  12  may be designed to deform upon contact with the captive screw  40  to further lock the components together. 
     A portion of retainer  12  defines keyway surfaces  74  which are also engaged by a keyed tool during installation or repair. As described hereinafter, the keyed tool engages the keyway surfaces  64  and  74  of body  11  and retainer  12 , respectively, to lock the body  11  and retainer  12  together so as to facilitate coupling the retainer  12  onto the screw  40 . 
     Referring now to  FIGS. 16 and 17 , an embodiment of a keyed tool  80  adapted for use with the body  11  and retainer  12  of  FIGS. 1-4  is illustrated. Tool  80  includes a hand graspable handle attached to shaft  82  having a keyed end  84 . Keyed end  84  includes a generally cylindrical receptacle  86  sized to receive a shaft of captive screw  40 . Keyed end  84  further includes key surfaces adapted to engage keyway surfaces  64 ,  74  of body  11  and retainer  12 , respectively. In this embodiment, keyed end  84  is a simple bifurcation of a hollow end of shaft  82 . 
     As shown in  FIG. 18 , the keyed end  84  of tool  80  is inserted into the first end  60  of body  11  during installation. A shaft portion of captive screw  40  received into receptacle  86 . As tool  80  is inserted into body  11  and rotated as needed, keyed end  84  engages the keyway  74  of retainer  12 , as shown in  FIG. 19  (body  11  removed from view). 
       FIG. 20  is a cutaway illustration showing the tool end  84  just prior to contact with the keyway surfaces  64 ,  74  of body  11  and retainer  12 . As tool  80  is further inserted and rotated into body  11 , keyed end  84  then engages keyway  64  of body  11  as shown in the detailed view of  FIG. 21 . Body  11  and tool  80  are separately shown in  FIG. 22  to illustrate the coupling between keyed end  84  and keyway surfaces  64  of body  11 . 
     With tool  80  fully inserted to engage the keyway surfaces  64 ,  74  of body  11  and retainer  12 , the components are locked together. Captive screw  40  can then be secured to retainer  12  by rotation of captive screw  40  relative to retainer  12 . The tool  80  thus provides an interface to both force the retainer  12  out of body  11  and also lock the body  11  and retainer  12  together while the captive screw is rotated into engagement with retainer  12 . With the hand-graspable version of tool  80 , torque applied to captive screw  40  is resisted by the coupling between the body  11  and panel  30  or transferred to the tool handle. If the body  11  is loosely secured to panel  30 , torque applied to captive screw  40  is counteracted with torque applied to tool  80 . Once tool  80  is removed, retainer  12  is unlocked from body  11  and the captive screw  40  and retainer  12  are free to rotate relative to body  11 . 
       FIGS. 23 and 24  illustrate another embodiment of a retainer  102  suitable with use with body  11 . In this embodiment, retainer  102  defines a keyed surface  104  which engages the keyway  64  of body  11 , thus allowing for assembly without an external tool. In operation, the retainer  102  is axially displaced within body  11  so that keyed surface  104  engages keyway  64  of body  11 , thereby locking the body  11  and retainer  102  together as the captive screw  40  is secured to retainer  102 . Once retainer  102  is displaced away from the keyway  64 , the body  11  and retainer are unlocked and the captive screw  40  and retainer are free to rotate relative to body  11 . 
       FIGS. 25 and 26  illustrated another embodiment of a retainer  120  suitable for use with a body  122 . In this embodiment, retainer  120  defines a keyed surface  124  which engage keyway surfaces  126  of body  122 . Keyed surface  124  has a hexagonal form which engages a corresponding hex-shaped keyway  126 . In operation, the retainer  120  is axially displaced within body  122  so that keyed surface  124  engages keyway surfaces  126  of body  122 . Once retainer  120  is axially displaced away from keyway surfaces  126 , the body  122  and retainer  120  are unlocked and the captive screw  40  and retainer are free to rotate relative to body  122 . A variety of different key and keyway surfaces are envisioned on body and retainer components of the present invention. 
       FIGS. 27 and 28  illustrate another body  130  and retainer  132  for use with an external tool (not shown) for holding the retainer  132  as the captive screw  40  is inserted into retainer  132 . Retainer  132  has one or more flats  134  adapted to be engaged by an external wrench or other tool. 
       FIGS. 29 and 30  illustrate another retainer  140  for use with body  11 . Keyway surfaces  142  are defined upon retainer  140  away from flange  144 . A rectangular aperture in retainer  140  forms the keyway surfaces  142 . Other aperture configurations would also be practicable. An external keyed tool (not shown) can engage keyway surfaces  64 ,  142  so as to lock the body  11  and retainer  140  together during assembly. 
       FIGS. 31 and 32  illustrate another body  150  and retainer  152 . Retainer  152  can be a spiral-formed wire component having an enlarged end  154  sized to prevent detachment of the retainer  152  from body  150 . Retainer  152  can be a wire having a triangular cross section formed to conform to threads of the captive screw. 
       FIGS. 33 and 34  illustrate another body  160  and retainer  162  wherein the retainer  162  snaps into body  160 . A deflecting portion  164  of body  160  is adapted to deflect as the flange  166  of retainer  162  is inserted into body  160 . In another embodiment the deflecting portion can be provided upon retainer  162 . 
       FIGS. 35 and 36  illustrate another embodiment of a body  170  and retainer  172  wherein the retainer  172  includes a relatively thin, broken flange  174  adapted to pass through a gap  176  in body  170 . During assembly, an edge of broken flange  174  is inserted into the gap  176  and the retainer  172  is rotated to pass the flange  174  into the body  170 . 
     Captive screw  40  includes a variety of threaded assemblies. For example,  FIG. 37  illustrates a captive screw  40  having a hand-graspable knob  180  connected to a threaded shaft  182 . In another example, captive screw  40  provides a handle. 
     An alternative embodiment of a body  190  is illustrated in  FIGS. 38 and 39 . A two-part body  190  includes a body cap  192  and body base  194  which are snap-fit together during assembly. The body cap  192  and body base  194  define a latch mechanism to secure the portions together. For example, body cap  192  includes a plurality of internal annular grooves  196  which are sized to engage an annular protrusion  197  on body base  194 . The plurality of grooves  196  allow the same body cap  192  and body base  194  to accommodate panels  30  of different thickness. The grooves and protrusions need not be continuous. For example, a plurality of disjointed grooves and protrusions could be utilized in another embodiment of body  190 . During assembly, the body base  194  is passed through an aperture in panel  30 . A flange  198  precludes body base  194  from passing through panel  30 . 
     Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.