Abstract:
The present invention discloses a self locking floating fastener. Further embodiments, forms, features, aspects, benefits, and advantages shall become apparent from the description and figures provided herewith.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application 61/203,892, filed Dec. 30, 2008, which is incorporated herein by reference. 
     
    
     GOVERNMENT RIGHTS IN PATENT 
       [0002]    This invention was made with Government support under FA8650-07-C-2803 awarded by United States Air Force. The Government may have certain rights in this invention. 
     
    
     FIELD OF THE INVENTION 
       [0003]    The present invention relates to a re-useable self locking floating fastener that may be used in place of rivets and the like. 
       BACKGROUND 
       [0004]    Threaded fasteners are used to fasten structure in many forms. Blind applications are defined by the lack of access to one side of the fastened structure i.e. when an individual can not torque a male fastener on one side and simultaneously place or hold a nut on the other side. One common method to alleviate this problem is to install a threaded insert into one side of the structure prior to assembly and then torque a male fastener into the insert. Another method is to use a rivet if the blind portion of the structure is too thin to install a threaded fastener into. One problem with using inserts is the initial cost in terms of manufacturing cost and labor required to precisely prepare the hole and install the insert. If the insert fails for any reason such as stripped threads the insert must be drilled out and the hole must be re-prepped before installing a new insert. Rivets are problematic in that they are only one use applications and must be drilled out if there is a problem with the rivet or if the structures require separation. In addition to the labor intensive costs associated with drilling out rivets or inserts there is also a possibility of foreign object damage (FOD) occurring with small pieces of drilled out metal entering sensitive areas of high value machines such a gas turbine engines and the like. The present invention addresses the problems associated with prior art fasteners by providing a novel and non-obvious solution for a reusable threaded fastener for blind installations. 
       SUMMARY 
       [0005]    The present invention discloses a self locking floating fastener. Further embodiments, forms, features, aspects, benefits, and advantages shall become apparent from the description and figures provided herewith. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
           [0007]      FIGS. 1A-1D  schematically depict a non-limiting example of a fastener in accordance with an embodiment of the present invention for clamping together two structures. 
           [0008]      FIG. 2  schematically depicts the fastener of  FIGS. 1A and 1B  with a fastener component expanded to fasten the two structures together. 
           [0009]      FIG. 3  is an exploded perspective view of a floating fastener according to the present invention; 
           [0010]      FIG. 4  is cross sectional view of the floating fastener of  FIG. 3  extending through a structure in an unlocked configuration; and 
           [0011]      FIG. 5  is cross-sectional view of the floating fastener of  FIG. 4  in a locked configuration. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    For purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
         [0013]    The present invention relates to a floating self locking fastener that can be inserted through a blind aperture and torque to a desired level. In one form, the floating self locking fastener is reusable. In one form, the floating self locking fastener operates to fasten separate components or structure of any conceived dimension together. In one aspect of present invention the floating fastener can be advantageously used to replace rivets in thin walled structures and the like. 
         [0014]    Referring now to  FIGS. 1A-1D , a non-limiting example of a fastener  100  in accordance with an embodiment of the present invention is schematically depicted. In one form, fastener  100  is adapted for fastening two structures  102  and  104  together. In other embodiments, fastener  100  may be adapted for fastening together any number of structures. Structures  102  and  104  have respective holes  106  and  108  into which portions of fastener  100  are admitted. Holes  106  and  108  may or may not be the same size. Structures  102  and  104  may be any metallic or nonmetallic structures sought to be affixed to one another. In one form, structures  102  and  104  are metallic sheets. In other embodiments, structures  102  and  104  may take other forms. 
         [0015]    In one form, fastener  100  includes a fastener component  110 , a fastener component  112  and a fastener component  114 . Fastener components  110 ,  112  and  114  may each take one or more of a variety of forms. Fastener components  110 ,  112  and  114  cooperate to fasten structures  102  and  104  together. 
         [0016]    In one form, fastener component  110  includes an end  116 , and end  118  and an opening  120 . The geometric shape of fastener component  110  may take any of a variety of forms. End  118  is structured, e.g., geometrically dimensioned, for reception into both holes  106  and  108 . End  116  is sized to prevent its entry into hole  106 , and is located adjacent a front wall of structure  102 . In one form, fastener component  110  includes a torquing feature  122  that is operative to transmit and/or react torque. In one form, torquing feature  122  is disposed on end  116 . In one form, torquing feature  122  is a hex shape. In other embodiments, torquing feature  122  may take other forms. In other embodiments, torquing feature  122  may be disposed on end  118  in addition to or in place of end  116 . In one form, torquing feature  122  is an anti-rotation feature operative to anti-rotate fastener component  110  relative to fastener component  112 . In other embodiments, torquing feature  122  may be an anti-rotation feature operative to anti-rotate fastener component  110  relative to one or both of structure  102  and  104 , e.g., such as a key that engages a slot in structure  102  and/or structure  104 . Torquing feature  122  is operative to prevent the rotation of fastener component  110  upon the rotation of fastener component  112 . 
         [0017]    End  118  of fastener component  110  includes a ramp  124  for expanding fastener component  114 . In one form, ramp  124  acts as a wedge to drive at least a portion of fastener component  114  radially outward. In one form, ramp  124  extends circumferentially around end  118  of fastener component  110 . In other embodiments, ramp  124  may only be disposed at one or more locations around the circumference of end  118 . End  118  also includes an anti-rotation feature  126  that is structured to engage an anti-rotation feature on fastener component  114  to anti-rotate fastener component  114  relative to fastener component  110 . In one form, anti-rotation feature  126  is a key extending from ramp  124 . In one form, a single key is employed, although the number of keys in other embodiments may vary with the application. In addition, in other embodiments, anti-rotation feature  124  may be positioned in other locations. Further, in other embodiments, anti-rotation feature  124  may take other forms, e.g., such as a slot that is structured to engage an anti-rotation feature, such as a key, on fastener component  114 . 
         [0018]    In one form, fastener  100  includes a resilient member  128 . In one form, resilient member  128  is operative to seal against structure  102 , e.g., against the front face or wall of structure  102  and/or hole  106 . In one form, resilient member  128  is disposed adjacent end  116 , e.g., opposite a head of fastener component  112 . In other embodiments, resilient member  128  may be disposed in other locations, including in or on end  116  and/or end  118 . In still other embodiments, fastener  100  may be devoid of resilient member  128 . In still other embodiments, other members, resilient or not, may be employed in addition to or in place of resilient member  128 . 
         [0019]    Fastener component  112  includes a head  130  and an extension  132 . Head  130  is structured, e.g., geometrically configured, to axially engage end  116  of fastener component  110  (the axial direction being a direction parallel to the center line  134  of fastener component  112 , e.g., left-to-right in the depiction of  FIG. 1A ). Extension  132  is structured, e.g., geometrically configured, to be received into opening  120  of fastener component  110 . In one form, extension  132  is a bolt shank with a threaded portion having threads  136 . Threads  136  may extend partially or fully along the length of extension  132 . 
         [0020]    Fastener component  112  includes a torquing feature  138  that is operative to transmit and/or react torque. In one form, torquing feature  138  is disposed on head  130 . In one form, torquing feature  138  is a hex socket. In other embodiments, torquing feature  138  may take other forms, including shapes extending into or out of head  130 . Torquing feature  138  is operative to impart rotation to fastener component  112 , e.g., via a tool or by hand. 
         [0021]    Fastener component  114  is structured for driving engagement with extension  132  of fastener component  112 . Fastener components  110 ,  112  and  114  are structured to translate fastener component  114  upon a rotation of fastener component  112 . Fastener component  114  and end  118  of fastener component  110  are structured to expand at least a portion of fastener component  114  upon a translation of fastener component  114  toward and against, and impart both an axial clamp load against structure  104  and a radial load against hole  108 . 
         [0022]    In one form, fastener component  114  is a threaded nut configured to engage threads  136  of extension  132  of fastener component  112 . In other embodiments, fastener component  114  may take other forms. In one form, fastener component  114  has a slotted end  140  with a plurality of slots  142  spaced apart circumferentially around fastener component  114 . Although 8 slots are depicted in  FIG. 1B , the number of slots may vary with the needs of the particular application. In the depiction of  FIG. 1B , end  118  of fastener component  110  is not shown for purposes of clarity. 
         [0023]    In one form, slots  142  are through-slots that extend through both the outer and inner diameters of slotted end  140 . In other embodiments, slots  142  may only extend partially through the inner and/or outer diameters of slotted end  140 . 
         [0024]    Slotted end  140  is structured for engagement with fastener component  110  to both anti-rotate fastener component  114  relative to fastener component  110 , and to expand slotted end  140  into engagement with structure  104 . Slotted end  140  expands upon translation toward and onto end  118  of fastener component  110  under the action of ramp  124 . In one form, slotted end  140  includes a ramp  144  operative to engage ramp  124  of fastener component  110 . In other embodiments, slotted end  140  may not include a ramp. In one form, slotted end  140  includes a tip surface  146  operative to engage structure  104 . In one form, tip surface  146  includes serrations  148 . Serrations  148  may take any convenient form, e.g., knurls. 
         [0025]    Fastener component  114  includes an anti-rotation feature that is structured to engage anti-rotation feature  126  of fastener component  110  to anti-rotate fastener component  114  relative to fastener component  110 . In one form, the anti-rotation feature is a slot  142 . In one form, a single slot  142  is employed as an anti-rotation feature, although the number of slots employed as anti-rotation features in other embodiments may vary with the needs of the particular application. In addition, in other embodiments, the anti-rotation feature of fastener component  114  may be positioned in other locations. Further, in other embodiments, the anti-rotation feature may take other forms, e.g., such as a key or other protrusion that is structured to engage an anti-rotation feature, such as a slot, on fastener component  110 . 
         [0026]    In one form, fastener  100  also includes a sealing member  150  disposed between and operative to seal between fastener component  110  and fastener component  112 . In one form sealing member  150  is disposed between head  130  of fastener component  112  and end  116  of fastener component  110 . In other embodiments, sealing member  150  may be positioned in other locations. In still other embodiments, fastener  100  may not include a seal for sealing between fastener component  110  and fastener component  112 . In one form, sealing member  150  is disposed in a seal gland  152 . In one form, gland  152  is formed in end  116  of fastener component  110 . In other embodiments, gland  152  may be formed in desired locations on one or both of fastener components  110  and  112 . Yet other embodiments may not include a gland for retaining sealing member  150 . 
         [0027]    Some aspects of a non-limiting example of an embodiment of the operation of fastener  100  are described thusly: Fastener components  110 ,  112  and  114  are assembled together, along with sealing member  150  and resilient member  128  for those embodiments so equipped. Fastener  100  is inserted into structures  102  and  104  via holes  106  and  108 , e.g., until end  116  of fastener component  110  (or resilient member  128 , for those embodiments so equipped) engages the front face of structure  102 . Then, torque is applied to rotate fastener component  112  via torquing feature  138 , while anti-rotating fastener member  110  with torquing feature  122 . In other embodiments, fastener component  110  may be rotated, while anti-rotating fastener component  112  via torquing feature  122 . In still other embodiments, both components  110  and  112  may be rotated, e.g., in opposite directions. The rotation of fastener component  112  relative to fastener component  110  results in the translation of fastener component  114  via the action of threads  136  of fastener component  112  engaging corresponding threads in fastener component  114 , since fastener component  114  is anti-rotated relative to fastener component  110  via the engagement of key  126  with slot  140 . The translation of fastener component  114  toward end  118  and onto ramp  124  of fastener component results in slotted end  140  expanding under the influence of ramp  124 , increasing the diameter of slotted end  140 . In one form, fastener component  114  is configured, in conjunction with fastener component  110 , to expand in such a manner so as to intercept hole  108  with tip surface  146  of slotted end  140 . Continued translation of fastener component  114  drives the serrated tip surface  146  of fastener component  114  into hole  108 , e.g., at the corner established by the intersection of hole  108  with the back wall or face of structure  104 , which imparts radial and axial loads to structure  104 , and clamps structures  102  and  104  together between end  116  of fastener component  110  and slotted end  140  of fastener component  114 . By providing serrations  148  in serrated end  140  of fastener component  114 , the potential for loosening of fastener  100  in service may be reduced. Also, the need for anti-rotation of fastener component  110  during the final stages of assembly are reduced or eliminated in some embodiments, since fastener component  114  may be anti-rotated via serrations  148  “biting” into structure  104 . In other embodiments, fastener  100  may be configured to provide only axial clamping loads between fastener component  114  and fastener component  110 , with or without serrations. 
         [0028]    Referring to  FIG. 3 , a non-limiting example of a floating self locking fastener  10  is in accordance with an embodiment of the present invention is illustrated therein. In one form, fastener  10  is a blind fastener, i.e., a fastener configured for use in a blind aperture, such as wherein access to the fastener is readily obtained only on one end. In one form, self locking fastener  10  includes a threaded bolt  12  having a head  14  with a drive socket  15  formed therein. The drive socket  15  can be in any form desired such as a recessed internal hex or a protruding connection. Furthermore, the drive socket  15  may be designed for standard tools or specially designed tools. A shank  16  extends from the head  14  and has a threaded portion  18  formed in the distal end thereof. 
         [0029]    A bolt housing  20  includes a head pocket  22  for the head  14  of the bolt  12  to rest therein. The bolt housing  22  can include an anti-torque feature  24  operable for receiving in an anti-torque tool (not shown) to restrict the bolt housing  20  from rotating when the threaded bolt  12  is torqued down. The bolt housing  20  can optionally include a seal groove  26  for applications that require a fluid seal or a resilient abutment and the like. An optional seal or resilient member  32  can be positioned within the seal groove  26  if desired. A nut ramp  28  is formed on one end of the bolt housing  20  opposite of the head pocket  22 . The bolt housing  20  includes at least one key  30  extending outward from the nut ramp  28 . 
         [0030]    A perforated nut  34  is designed to threadingly engage with the threaded bolt  12 . The perforated nut  34  includes a plurality of expandable tabs  36  circumferentially extending around the perimeter of the nut  34 . A plurality of slots  38  define the boundary between each tab  36 . The nut  34  includes a threaded aperture  44  for engaging the threaded portion  18  of the bolt  12 . 
         [0031]    Referring now to  FIG. 4 , the nut  34  is threaded onto the threaded portion  18  of the bolt  12  after the bolt  12  has been inserted through the bolt housing  20 . The nut  34  can be rotated down the threaded portion  18  until at least one slot  38  of the nut  34  engages with at least one key  30  of the bolt housing  20 . The key  30  of the bolt housing  20  will prevent the nut  34  rotating relative to the bolt housing  20 . The self locking fastener  10  can then be inserted through an opening  42  formed within structure having at least two walls  44   a,    44   b  coupled together. After the fastener  10  is positioned within the through opening  42  the bolt  12  can be further torqued causing the nut  34  to move up the ramp  28  of the bolt housing  20  toward the wall  44   b.  As the nut  34  travels up the ramp  28  the expandable slots  36  will be elastically forced radially outward and an abutment edge  48  will engage the wall  44   b  an a manner that will hold the fastener  10  in place and prevent the walls  44   a  and  44   b  from separating as shown in  FIG. 5 . The threaded portion  18  of the bolt  12  can have deformable threads  46  to prevent the bolt  12  from inadvertently loosening after installation. A seal  50  can be positioned at an interface between the bolt head  14  and the head pocket  22  to prevent fluid from escaping through the interface. 
         [0032]    Embodiments of the present invention include a fastener comprising a bolt having a drive head and a threaded shank extending therefrom; a bolt housing having a bolt receiving pocket adjacent one end and a nut ramp adjacent an opposing end; at least one key formed on the bolt housing proximate the nut ramp; and an expandable nut having at least two expandable tabs with a key receiving slot formed therebetween. 
         [0033]    In a refinement, the fastener further comprises a resilient member disposed on the bolt housing between the bolt receiving pocket and the nut ramp. 
         [0034]    In another refinement, the fastener further comprises a groove in the bolt housing for retaining the resilient member with the bolt housing. 
         [0035]    In yet another refinement, the resilient member is a seal. 
         [0036]    In still another refinement, the fastener further comprises a seal disposed in a seal gland formed in at least one of the bolt and the bolt housing, wherein the seal is operative to seal between the bolt and the bolt housing. 
         [0037]    In yet still another refinement, the seal gland is disposed in the drive head. 
         [0038]    In a further refinement, the bolt housing includes an anti-torque feature operative to transmit and/or react torque. 
         [0039]    Embodiments of the present invention include a method of fastening at least two structures together comprising: sliding a threaded bolt through a bolt housing having a ramp with a key; torquing an expandable nut with at least two expandable tabs and a key slot formed therebetween onto the bolt until the key engages the key slot; positioning the fastener through an opening formed in the at least two structures; drawing the expandable nut up the ramp and expanding the tabs to engage a back wall of the one of the structures; and torquing the bolt to a desired torque level. 
         [0040]    Embodiments of the present invention include a fastener for fastening at least two structures together, comprising: a first fastener component having a first end, a second end, and an opening extending through the first end and the second end, wherein the second end is structured for reception into both a first hole in a first structure of the at least two structures and a second hole in a second structure of the at least two structures; and wherein the first end is sized to prevent entry into the first hole; a second fastener component having a head and an extension adjacent to the head, wherein the head is structured to axially engage the first end of the first fastener component; and wherein the extension is structured to be received into the opening of the first fastener component; and a third fastener component structured for driving engagement with the extension of the second fastener component, wherein the first, second and third fastener components are structured to translate the third fastener component upon rotation of the second fastener component; and wherein the third fastener component and the second end of the first fastener component are structured to expand at least a portion of the third fastener component upon a translation of the third fastener component and impart both an axial clamp load against the second structure and a radial load against the second hole. 
         [0041]    In a refinement, the second end of the first fastener component includes a ramp for expanding the third fastener component. 
         [0042]    In another refinement, the extension of the second fastener component includes a threaded portion, and wherein the third fastener component is a nut. 
         [0043]    In yet another refinement, the third fastener component has a slotted end structured for engagement with the first fastener component. 
         [0044]    In still another refinement, the first fastener component has a first anti-rotation feature and the third fastener component has a second anti-rotation feature; and wherein the first anti-rotation feature and the second anti-rotation feature are operative to anti-rotate the third fastener component relative to the first fastener component. 
         [0045]    In yet still another refinement, one of the first anti-rotation feature and the second anti-rotation feature includes a slot; and wherein the other of the first anti-rotation feature and the second anti-rotation feature includes a key structured to engage the slot to anti-rotate the third fastener component relative to the first fastener component. 
         [0046]    In a further refinement, the first fastener component includes an anti-torque feature for preventing rotation of the first fastener component upon rotation of the second fastener component. 
         [0047]    In a yet further refinement, the fastener further comprises a resilient member disposed adjacent to the first end of the first fastener component opposite the head of the second fastener component. 
         [0048]    In a still further refinement, the fastener further comprises a sealing member disposed between the first end of the first fastener component and the head of the second fastener component. 
         [0049]    In a yet still further refinement, the fastener further comprises a sealing member and a gland, wherein the gland is formed in at least one of the first fastener component and the second fastener component, wherein the sealing member is operative to seal between the first fastener component and the second fastener component. 
         [0050]    In an additional refinement, the first fastener component has a first torquing feature operative to transmit and/or react torque; and wherein the second fastener component has a second torquing feature operative to transmit and/or react torque. 
         [0051]    In another refinement, the third fastener component includes a serrated end operative to engage the second hole. 
         [0052]    Embodiments of the present invention include a fastener for fastening at least two structures together, comprising: a first fastener component having a first end, a second end, an opening extending through the first end and the second end, and a first anti-rotation feature, wherein the second end is structured for reception into both a first hole in a first structure of the at least two structures and a second hole in a second structure of the at least two structures; and wherein the first end is sized to prevent entry into the first hole; a second fastener component having a head and an extension adjacent to the head, wherein the head is structured to axially engage the first end of the first fastener component; and wherein the extension is structured to be received into the opening of the first fastener component; and a third fastener component having a second anti-rotation feature operative to anti-rotate the third fastener component relative to the first fastener component, wherein the third fastener component is structured for driving engagement with the extension of the second fastener component, wherein the first, second and third fastener components are structured to translate the third fastener component upon rotation of the second fastener component to clamp the at least two structures together. 
         [0053]    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 embodiment(s), 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 permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.