Abstract:
A fastener with a locking mechanism includes an elongated bolt member with threaded segment defining a banking feature and generally planar surfaces, a nut member, a washer member, and a lock member. The nut member has a threaded bore for cooperating with the threaded segment of the bolt member and a peripheral edge with a flat side defining an axial slot. 
     The washer member has a central bore with a banking portion that complements the banking feature of the bolt member such that, when the threaded segment is inserted in the central bore, the washer member moves axially and is rotatably fixed relative to the bolt member. The washer member has an axially projecting circumferential wall with radially inward facing engagement teeth for intermeshing with teeth of the lock member. The lock member has a spring finger upstanding from the annular body that is received in the axial of the nut member for fixing the lock member in rotation relative the nut member.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to and the benefits of U.S. Provisional Patent Application No. 62/148,846 filed Apr. 17, 2015, and U.S. Provisional Patent Application No. 62/193,437 filed Jul. 16, 2015, each of which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The subject invention is directed generally to fasteners, and more particularly to locking mechanisms for threaded fasteners. 
         [0004]    2. Background of the Related Art 
         [0005]    Fasteners commonly include mechanisms for ensuring that fastener elements do not loosen over time, potentially allowing joined elements to loosen or separate. Examples of mechanisms include thread bore inserts, and screw thread profiles that deform when tightened. Fasteners accessories like lock washers, cotter pins, and lock wires are also commonly used with fasteners to prevent fastener elements from loosening. Adhesive materials, like epoxy, can be applied to fastener threads to stake fastener elements to prevent fastener elements from loosening. Examples of mechanisms, fastener accessories, and adhesives are disclosed in U.S. Pat. No. 5,460,468 to DiStacio; U.S. Pat. No. 5,538,378 to Van der Drift; and U.S. Pat. No. 5,713,708 to Van der Drift et al., each of which is incorporated herein by reference. Conventional fastener mechanisms, accessories, and adhesive materials may not be suitable for some applications, such as high temperature environments or with structures subject to vibration. 
         [0006]    Such conventional mechanisms, accessories, and adhesive materials have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved fasteners. The present disclosure provides a solution for this need. 
       SUMMARY OF THE INVENTION 
       [0007]    The subject invention is directed to a fastener locking mechanism including an elongated bolt member having a threaded segment with a banking feature, a washer member having a circumferential wall with radially inward facing engagement teeth and a banking portion that complements the banking feature of the bolt member, a lock member having an annular body with an upstanding spring finger and a tooth disposed on a radially outward surface of the annular body, and a nut member having a circumferential flat with an axial slot and a threaded bore corresponding to threaded segment of the bolt member. The banking feature of the bolt member cooperates with the banking portion of the washer member to fix the washer member in rotation relative to the bolt member. The spring finger of the lock member cooperates with the axial slot of the nut member to fix the lock member in rotation relative to the nut member. The tooth of the lock member is displaceable radially relative to the bolt member for engaging and disengaging the engagement teeth of the washer member. In a radially outer position, the tooth of the lock member intermeshes with the engagement teeth of the washer member to fix the lock member and nut member in rotation relative to the washer member. In a radially inner position, the tooth of the lock member is rotatable relative to the washer member such that the lock member and nut member are rotatable relative to the washer member and the bolt member. 
         [0008]    In accordance with certain embodiments, the bolt member can include a flat. The flat can extend axially along a length of bolt member. The banking feature of the bolt member can include the flat. The flat can be radially adjacent to the threaded segment of the bolt member. The flat can be a first flat, and the bolt member can include one or more second flats. The banking feature can include both the first flat and the second flat. The second flat can extend axially along the bolt member. The second flat can be disposed on a side of the bolt member diametrically opposite the first flat. The threaded segment can extend circumferentially about the bolt member and couple the first flat with the second flat. 
         [0009]    It is also contemplated that, in accordance with certain embodiments, the washer member can have opposed axial surfaces separated by an axial thickness of the washer member. A circumferential wall can extend from a periphery axially from a surface of washer member. Engagement teeth can be disposed an a radially inner surface of the circumferential wall. The engagement teeth can extend radially inward from the circumferential wall. A central aperture can extend through the thickness of the washer member between the axial surfaces of the washer member. The central aperture can include the banking portion that complements the banking feature of the bolt member. For example, one or more flat segments can bound the central aperture. The flat segment can correspond with the banking feature of the bolt member. The central aperture can include one or more arcuate segments bounding the central aperture. The arcuate segment can correspond to the threaded segment(s) of the bolt member. The central aperture can include both flat and arcuate segments, and a stress reduction feature can be disposed at an intersection of a flat segment and an arcuate segment. 
         [0010]    In certain embodiments, the lock member can include a spring finger having a free end and a fixed end. The free end can be disposed radially inward of the fixed end. The fixed end can be connected to the annular body of the lock member. The tooth and the spring finger can be circumferentially aligned with one another. The annular body of the lock member can have a round, oval, square, rectangular, or any suitably shaped axial profile. The annular body can be deformable, for example becoming more round (or more elliptical) in response to inward force exerted on the spring finger at a location between the fixed and free ends of the spring finger. The spring finger can be a first spring finger, and the lock member can include a second spring finger connected to the annular body on a side of the annular body opposite the first spring finger. 
         [0011]    In accordance with certain embodiments, the lock member can have a first and second teeth that each extend radially outward from the annular body of the lock member. The first and second teeth can be circumferentially adjacent to one another. The first and second teeth can also be circumferentially aligned to the spring tab. The first and second teeth can be disposed on opposite sides of the annular body of the lock member such that each extends radially in a direction opposite the other. The second tooth can be circumferentially aligned with a second spring finger of the lock member. It is also contemplated that more than one circumferentially adjacent tooth can be aligned to a first spring finger, and that more than one circumferentially adjacent tooth can be aligned to the second spring finger. 
         [0012]    It is also contemplated that, in accordance with certain embodiments, the nut member can have an annular recess. The annular recess can have a diameter that is less than a diameter of the annular body of the lock member. The nut member can have a circumference with a plurality of faces. The plurality of faces of the nut member can form a hexagonal circumference extending about the nut member. One or more of the faces of the nut member can have an axial slot. The axial slot can extend between the annular recess and an end of the nut member opposite the annular recess of the nut member. It is contemplated that the nut member can have faces with axial slots disposed on faces that are diametrically opposed to one another. 
         [0013]    In an aspect, the threaded segment and banking feature of the bolt member, central aperture and engagement teeth of the washer member, tooth and spring finger of the lock member, and axial slot of the nut member can cooperate as a locking mechanism. The locking mechanism can have a locked position wherein the annular body urges the lock member tooth radially outward such that the tooth intermeshes with the engagement teeth of the washer member, fixing the lock member in rotation relative to the washer member and preventing loosening of the nut member from the bolt member. The locking mechanism can have a tighten or release position wherein the annular body of the lock member urges the lock member tooth radially inward, rendering the lock member and nut member rotatable relative to the washer member and bolt member. It is contemplated that lock member can have a spring preload that normally urges the lock member tooth radially outward, and that a force exerted on the spring finger of the lock member can urge the lock member tooth radially inward to move to the reconfigure the locking mechanism from the locked position to the tighten or release position. 
         [0014]    In another aspect, a spinal fixation system includes a fastener locking mechanism as described above and a rod. The rod seats in the bolt member and below the washer member. It is contemplated that tightening the nut member exerts force on the washer member which in turn urges the rod against the bolt member. 
         [0015]    In certain embodiments, the bolt member can have a head portion coupled to an end of a stem section. The head portion can be fixed relative to the stem portion. A joint can be interposed between the head portion and the stem portion, the head portion thereby being movable relative to the stem portion. The head portion pivotable relative to the stem portion, such as in a conical movement envelope. The head portion can have a first threaded segment and the stem portion can have a second threaded segment. The first threaded segment can be a male threaded segment corresponding to a female threaded segment defined by the bore of the nut member. The second threaded segment can taper between an end adjacent to the head member and an end of the stem portion opposite the head portion. It is contemplated that the second threaded segment can have threads adapted for seating the bolt member to a bone structure, such as a pedicle. 
         [0016]    In accordance with certain embodiments, the bolt member can include a tulip head. The tulip head can have a slot extending therethrough for seating the rod. The slot can be centrally disposed, extending across the top of the bolt member. The slot can be laterally disposed, extending across a side of the bolt member. Lobes can be defined on opposite sides of the slot. The lobes can have the banking feature of the bolt member defined thereon. The lobes can have the threaded segment of the bolt member defined thereon. In a contemplated exemplary embodiment, each lobe has portions of both the threaded segment and the banking feature defined thereon. 
         [0017]    It is also contemplated that, in accordance with certain embodiments, the washer member can include a central bar portion. The central bar portion can extend across the washer member central aperture and divide the central aperture into first and second portions. One lobe of the bolt member tulip head can extend through the first portion of the central aperture, and the another lobe of the bolt member tulip head can extend through the second portion of the central aperture. The central bar portion can extend from the banking portion of the washer member such that, when the central bar portion is seated with the slot of the tulip head, the washer member is fixed in rotation relative to the tulip head. It is contemplated that central bar portion can seat slot of the tulip head, overlay the rod, and can be disposed between the nut member, lock member, and the stem of the bolt member. 
         [0018]    It should be appreciated that the present technology can be implemented and utilized in numerous ways, including without limitation as a process, an apparatus, a system, a device, a method for applications now known and later developed. These and other unique features of the technology disclosed herein will become more readily apparent from the following description and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    So that those having ordinary skill in the art to which the disclosed technology appertains will more readily understand how to make and use the same, reference may be had to the following drawings. 
           [0020]      FIG. 1  is an exploded perspective view of a fastener device constructed in accordance with the present disclosure, showing a nut member, a lock member, a washer member, and a bolt member of the fastener device; 
           [0021]      FIG. 2  is a perspective view of the fastener device of  FIG. 1 , showing the fastener device in an assembled configuration; 
           [0022]      FIG. 3  is a perspective view of the bolt member of  FIG. 1 , showing the elongated body, threaded segment, and banking feature of the bolt member; 
           [0023]      FIG. 4  is a perspective view of the nut member of  FIG. 1 , showing the threaded bore, annular recess, hexagonal recess, and an exemplary axial slot of the nut member; 
           [0024]      FIG. 5  is a perspective view of the lock member of  FIG. 1 , showing the deformable body, upstanding spring fingers, and teeth of the lock member; 
           [0025]      FIG. 6  is a perspective view of the washer member of  FIG. 1 , showing the washer member central aperture and banking portion, circumferential lip, and radial teeth oriented radially inwards relative to the circumferential lip; 
           [0026]      FIG. 7  is a perspective view of fastener of  FIG. 1 , showing the fastener and fastener locking mechanism in a locked position; 
           [0027]      FIG. 8  is a perspective view of the fastener of  FIG. 1 , showing the fastener and fastener locking mechanism in a release or tighten position; 
           [0028]      FIG. 9  is an exploded perspective view of another embodiment of fastener device constructed in accordance with the present disclosure, showing a bone fixation system including a locking mechanism in accordance with the present disclosure; 
           [0029]      FIG. 10  is a perspective view of the bolt member of  FIG. 9 , showing the bolt member stem and tulip head; 
           [0030]      FIG. 11  is a perspective view of the washer member of  FIG. 9 , showing the washer member central bar portion; and 
           [0031]      FIGS. 12-14  are perspective views of embodiments of nut member and lock member for the fasteners described herein, showing spring member protrusions and corresponding protrusion sockets define within the nut member axial slots. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0032]    The present disclosure overcomes many of the prior art problems associated with threaded fasteners. In general, threaded fasteners are used to fixedly connect two or more pieces in a variety of applications such as, without limitation, with surgical implants, industrial applications, aerospace applications, and building applications. Among other features and benefits, the disclosed fastening devices and systems can provide one or more of quick and easy installation and/or removal, low torque requirements, vibration resistant secured tightness, and/or single end access for blind fastening applications. The advantages, and other features of the technology disclosed herein, will become more readily apparent to those having ordinary skill in the art from the following detailed description of certain preferred embodiments taken in conjunction with the drawings which set forth representative embodiments of the present invention and wherein like reference numerals identify similar structural elements. 
         [0033]    All relative descriptions herein such as upward, downward, left, right, up, down, length, height, width, thickness and the like are with reference to the Figures, and not meant in a limiting sense. Additionally, the illustrated embodiments can be understood as providing exemplary features of varying detail of certain embodiments, and therefore, features, components, modules, elements, and/or aspects of the illustrations can be otherwise combined, interconnected, sequenced, separated, interchanged, positioned, and/or rearranged without materially departing from the disclosed fastener assemblies. Additionally, the shapes and sizes of components are also exemplary and can be altered without materially affecting or limiting the disclosed technology. 
         [0034]      FIG. 1  shows a fastener with a locking mechanism constructed in accordance with the present disclosure designated generally by reference numeral  100 . Fastener device  100  generally includes an elongated bolt member  110 , a washer member  120 , a lock member  130 , and a nut member  140 . Bolt member  110  has a threaded segment  114 . Threaded segment  114  includes male threads corresponding to female threads disposed on nut member  140 . One or more of bolt member  110 , washer member  120 , lock member  130 , and nut member  140  may include plastic, metal, a combination thereof, or any other suitable material. 
         [0035]    With reference to  FIG. 2 , washer member  120  seats about threaded segment  114  such that washer member  120  is rotateably fixed and axially displaceable relative to bolt member  110 . Lock member  130  seats about threaded segment  114  of bolt member  110  and against an axial face of washer member  120 . Nut member  140  has female threads that thread engage male threads on threaded segment  114 , and is disposed axially along bolt member  110  such that nut member  140  seats against washer member  120 . Lock member  130  seats about threaded segment  114  and is axially interposed between washer member  120  and nut member  140 . 
         [0036]    With reference to  FIG. 3 , an exemplary bolt member  110  is shown. Bolt member  110  defines a fastener axis A and, in the illustrated exemplary embodiment, includes a head portion  112  disposed on an end opposite threaded segment  114 . Threaded segment  114  has a banking feature  116  that, in the illustrated exemplary embodiment, includes a first longitudinally extending flat  116 A and an opposed second longitudinally extending flat  116 B. It is to be understood and appreciated that other banking feature geometries are possible within the scope of the present disclosure such as a single flat portion, notches, grooves, convex portions, concave portions, protrusions, slots and/or combinations thereof. Examples of such features are shown and described in U.S. Patent Application Publication No. 2014/0308089 A1, the contents of which incorporated by reference herein in their entirely. 
         [0037]    With reference to  FIG. 4 , nut member  140  is shown. Nut member  140  includes a bore  142  having female threads, an annular recess  144 , one or more slotted circumferential face  146 , and one or more continuous face  147 . Bore  142  extends between axially opposed faces of nut member  140 . Annular recess  144  extends circumferentially about bore  142  and adjacent to the tool engagement faces of nut member  140 . The one or more slotted circumferential face  146  and one or more continuous face  147  define tool engagement faces that extend axially between annular recess  144  and an axial face of nut member  140  that is opposite annular recess  144  and circumferentially about nut member  140 . The tool engagement faces may correspond to one or more common tools, such as a wrench or socket, and in the illustrated exemplar embodiment define a hexagonal circumference. This allows for tightening or loosening nut member  140  using a common hand tool and without requiring use of a specialized tool. 
         [0038]    The one or more slotted circumferential face  146  defines an axial slot  148 . Axial slot  148  extends axially along slotted circumferential face  146  between annular recess  144  and the axial face of nut member  140  opposite annular recess  144 , and has a circumferential width corresponding to the width of spring finger  134  (shown in  FIG. 5 ) and spring finger  136  (shown in  FIG. 5 ). This allows nut member  140  to cooperate with the preload of spring finger  134  such that, when axial slot  148  aligns in rotation about fastener axis A (shown in  FIG. 3 ), spring finger  134  snaps into axial slot  148 . As will be appreciated by those of skill in the art in view of the present disclosure, snapping spring finger  134  into axial slot  148  fixes lock member  130  in rotation relative to nut member  140 . 
         [0039]    In the illustrated exemplary embodiment shown in  FIG. 4  axial slot  148  is a first axial slot and nut member  140  includes a second axial slot  149 . Second axial slot  149  is disposed on a diametrically opposed side of nut member  140 , i.e. on a side of axis A opposite first axial slot  148 , and on a slotted face that is substantially parallel to slotted circumferential face  146 . As will be appreciated by those of skill in the art in view of the present disclosure, nut member  140  can have one, two, or more than two axial slots. The number of axial slots on nut member  140  may correspond in number and circumferential position relative to those of lock member  130 . Although two axial slots are shown in the illustrated exemplary embodiment, it is to be understood and appreciated that nut member  140  can have a single axial slot or more than two axial slots, as suitable for an intended application. 
         [0040]    With reference to  FIG. 5 , lock member  130  is shown. Lock member  130  includes a deformable annular body  132 . In the illustrated exemplary embodiment annular body  132  has a ring-like shape. It is contemplated that annular body  132  may be round, oval, ellipsoid, or any other suitable shape, and is constructed from a resilient material, such as an elastomer or spring steel. Response to a radial force exerted thereon by one or more spring fingers  134 , annular body  132  may become more or less round depending upon the amount of radial force exerted on annular body  132  and the spring constant of lock member  130 . 
         [0041]    Spring finger  134  upstands from annular body  132  and extends between a fixed end  134 A and a free end  134 B. Fixed end  134 A connects to annular body  132 . Spring finger  134  extends radially inward from fixed end  134 A such that free end  134 B is disposed radially inward of fixed end  134 A. In the illustrated exemplary embodiment, spring finger  134  is a first spring finger and lock member  130  includes a second spring finger  136 . Second spring finger  136  is similar to first spring tab  134 , and is additionally connected to annular body  132  such that second spring finger  136  faces first spring finger  134  on a side of lock member  130  that is diametrically opposed to the first spring finger  134 . 
         [0042]    A tooth  138  is disposed on the radially outer surface of lock member  130  and is circumferentially aligned relative to spring finger  134 . Tooth  138  includes a locking face  138 B and a sliding face  138 A that correspond to the locking faces and sliding faces of washer member  120  (shown in  FIG. 4 ). This allows a tool, e.g. tool  10  (shown in  FIG. 8 ), to slidably engage spring finger  134 , thereby radially displacing tooth  138  relative to the engagement teeth  126  of washer member  120 . In the illustrated exemplary embodiment, tooth  138  is one of a plurality of teeth, and a second tooth  139  is disposed on a diametrically opposite side of annular body  132  circumferentially adjacent to second spring finger  136 . First tooth  138  and/or second tooth  139  can each be one of a plurality of circumferentially adjacent teeth arranged about the radially outer surface of annular body  132  for fixing lock member  130  in rotation relative to washer member  120  (shown in  FIG. 6 ). 
         [0043]    With reference to  FIG. 6 , washer member  120  is shown. Washer member  120  has a central bore  121  that extends between a first axial face  129  and an opposed second axial face  123 . First axial face  129  is separated from second axial face  123  by an axial thickness T of washer member  120 . Central bore  121  is bounded by a plurality of banking segments that complement banking feature  116  of bolt member  110  (shown in  FIG. 3 ). In the illustrated exemplary embodiment the plurality of banking segments includes pair of flats coupled by a pair of arcuate segments and a plurality of stress reduction features. In this respect central bore  121  includes a first flat  124 A and a second flat  124 B that bound central bore  121 . A first arcuate segment  124 C extends between first flat  124 A and second flat  124 B. A second arcuate segment  124 D faces first arcuate segment  124 C and extends between opposite ends first flat  124 A and second flat  124 B. Stress reduction features  125  are defined at corners of central bore  121  where respective flats and arcuate segments intersect one another. It will be appreciated that other banking segments are contemplated within the scope of the present disclosure. 
         [0044]    A circumferential wall  127  extends axially from first axial face  129  about the periphery of washer member  120 . Circumferential wall  127  has a plurality of engagement teeth  126 . Engagement teeth  126  are distributed about a radially inner face of circumferential wall  127  and extend radially inward from circumferential wall  127  and towards central bore  121 . In the illustrated exemplary embodiment, engagement teeth  126  include a locking face  126 A that is substantially orthogonal with respect to circumferential wall  127  and a sliding face  126 B that is oblique relative to circumferential wall  127 . 
         [0045]    With reference to  FIGS. 7 and 8 , fastener  100  is shown in an assembled configuration.  FIG. 7  shows fastener  100  with the locking mechanism  102  in a locked position.  FIG. 8  shows fastener  100  with locking mechanism  102  in a tighten or release position. In the locked position shown in  FIG. 7 , washer member  120 , lock member  130 , and nut member  140  are each fixed both axially and in rotation relative to bolt member  110 . In the tighten or release position shown in  FIG. 8 , lock member  130  and nut member  140  are both rotationally free relative to bolt member  110 . As will be appreciated, rotation of nut member  140  relative to bolt member  110  displaces nut member  140  axially relative to bolt member  110 , allowing corresponding axial displacement of washer member  120  and lock member  130  relative to bolt member  110 . 
         [0046]    As indicated in  FIG. 7 , fixed end  134 A of spring finger  134  assumes a locked position radial offset P 1  when locking mechanism  102  is in the locked position. At the locked position radial offset P 1 , deformable annular body  132  is urged radially outward at the circumferential position corresponding to spring finger  134 . Urging annular body  132  radially outward at the location corresponding to spring finger  134  in turn urges tooth  138  of lock member  130  against engagement teeth  126  of washer member  120 . Consequently, at circumferential arrangements where lock member tooth locking surface(s)  138 A align and overlap in a coplanar arrangement with a corresponding locking surface  126 A of engagement tooth  126 , lock member  130  becomes rotational fixed relative to washer member  120 . 
         [0047]    As also indicated in  FIG. 7 , free end  134 B of spring finger  134  seats within axial slot  148  when locking mechanism  102  is in the locked position. Seating free end  134 B of spring finger  134  in axial slot  148  fixes lock member  130  in rotation with nut member  140 . Fixing lock member  130  in rotation relative to nut member  140  causes lock member  130  to rotation with nut member  140 . Consequently, when tooth  138  of lock member  130  seats against engagement teeth  126  of washer member  120 , lock member  130  becomes fixed in rotation relative to washer member  120 . As will be appreciated, since washer member  120  is fixed in rotation relative to both member the complementary banking member and banking portion of each, seating tooth  138  of lock member  130  against engagement tooth  126  also fixes nut member  140  in rotation relative to bolt member  110 . 
         [0048]    With reference to  FIG. 8 , fastener  100  is shown with locking mechanism  102  in the tighten or release position. Locking mechanism  102  moves from the locked position (shown in  FIG. 7 ) to the illustrated tighten or release position by seating a tool over an end of fastener  100 . In this respect tool  10  includes a finger contact surface  12  extending circumferentially about an interior recess of tool  10 . Upon seating tool  10  seats over nut member  140  by axially displacing tool  10  relative to fastener  100 , contact surface  12  comes into contact and exerts a contact force F on spring finger  134 , oriented obliquely relative thereto, at a location between fixed end  134 A and free end  134 B of spring finger  134 . Contact force F urges spring finger  134  radially inward relative to fastener axis A, deforming annular body  132  such that fixed end  134 A of spring finger  134  assumes an unlocked or tighten radial offset P 2 . 
         [0049]    Unlocked or tighten radial offset P 2  is smaller than locked radial offset P 1 . Moving fixed end  134 A of spring finger  134  from locked radial offset P 1  to unlocked or release radial offset P 2  causes the locking face  138 B of tooth  138  to slide across locking face of engagement tooth  126 . This disengages tooth  138  of lock member  130  from engagement tooth  126  of washer member  120 , allowing lock member  130  and nut member  140  to rotate relative to washer member  120  and bolt member  110 . As will be appreciated, tool  10  may be rotated either clockwise or counterclockwise about fastener axis A to displace nut member  140  axially in either direction along fastener axis A, tightening nut member  140  or loosening nut member  140  as appropriate. Thus, when a tool such as a conventional socket wrench is applied to nut member  140 , lock member  130  is deflected radially inward such that teeth of lock member  130  disengage teeth of washer member  120 , thereby allowing rotation of lock member  130  and nut member  140  relative to washer member  120  and bolt member  110 . 
         [0050]    Referring now to  FIG. 9 , another embodiment of a fastener with a locking mechanism constructed in accordance with the present disclosure designated generally by reference numeral  200 . Fastener  200  is similar to fastener  100  and generally includes an elongated bolt member  210 , a washer member  220 , a lock member  230 , and a nut member  240 . Nut member  240  is similar to nut member  140  (shown in  FIG. 6 ). Lock member  230  is similar to lock member  130  (shown in  FIG. 5 ). 
         [0051]    With reference to  FIG. 10 , bolt member  210  is similar to bolt member  110 , and is additionally configured as fixation system for coupling a rod  204  to bone, for example as a spinal pedicle screw rod system. Bolt member  210  includes a tulip head  211  and an elongated stem  212 . Elongated stem  212  includes a second threaded segment  217  that tapers from an end adjacent to tulip head  211  to an end opposite tulip head  211 , thereby facilitating insertion of elongated stem  212  into bone structure, such as a pedicle. 
         [0052]    Tulip head  211  includes a lateral slot  213  with a first prong  214 A and an opposed second prong  214 B. Tulip head  211  has a first threaded segment  215  with a banking feature  216 . First threaded segment  215  has male threads that correspond to female threads defined within the central bore of nut member  240  (shown in  FIG. 9 ). Banking feature  216  complements the banking feature of washer member  220  (shown in  FIG. 11 ) such that washer member  220  is rotatably fixed and axially displaceable relative to tulip head  211 . Banking feature  216  is split by lateral slot  213 , thereby allowing for rod  204  to seat therein and to extend therethrough, allowing for rod  204  to be rotationally fixed and axially displaceable relative to tulip head  211 . With reference now to  FIG. 11 , washer member  220  is shown. Washer member  220  is similar to washer member  120  and additionally includes a central bar portion  227 . Central bar portion  227  is disposed within washer member central aperture  225  and extends between first flat  224 A and second flat  224 B of washer member banking portion  224 . In this respect central bar portion  227  spans central aperture  225 , allowing transfer of force from nut member  240  (shown in  FIG. 9 ) in a force flow path including central bar portion  227  to rod  204  (shown in  FIG. 10 ). As will be appreciated, central bar portion  227  extends between opposing sides of lateral slot  213  to create two discrete axial apertures on diametrically opposed flats of the tulip head banking feature. 
         [0053]    Referring to  FIGS. 9-11 , the flats on first prong  214 A (shown in  FIG. 10 ) and second prong  214 B are configured to mate with respective first flat inner surface  224 A or second inner surface  224 B of washer member  220 . This rotationally fixes washer member  220  relative to tulip head  211  when first prong  214 A and second prong  214 B of tulip head  211  are inserted into the discrete axial apertures bounded by central bar portion  227 . This allows axial movement of washer member  220  along the prongs of tulip head  211  to secure rod  204  within lateral slot  213  between washer member  220 , lock member  230 , and tulip head  211 . After rod  204  is placed within lateral slot  213 , washer member  220  is inserted over prongs of tulip head  211 , and central bar portion  227  displaces axially downward within lateral slot  213  response to downward axial displacement of nut member  240  to rest against rod  204 . 
         [0054]    Those skilled in the art will readily appreciate that because nut member  240  and washer member  220  are substantially similar to nut member  140  and washer member  120 , a common tool such as a wrench or socket can be used to tighten rod  204  to the fastener  100  or remove rod  204  from fastener  100  by either rotating nut member  240  clockwise or counterclockwise. Traditional bone fixation systems tend to require a significant amount of torque in order to lock a rod to a fastener or to remove the rod from the fastener. This can be the case, for example, in conventional external bone fixation systems and/or internal bone fixation systems like spinal pedicle screw rod systems. Those skilled in the art will readily appreciate, however, that embodiments of the present invention reduce the amount of torque required as compared with traditional spinal pedicle screw rod systems. 
         [0055]    With reference to  FIGS. 12-14 , a nut member  340  and a lock member  330  are shown according to another embodiment. Referring to  FIG. 12 , nut member  340  is shown. Nut member  340  is similar to nut member  140  (shown in  FIG. 6 ) and additionally includes a stepped axial slot  348 . Stepped axial slot  348  has a first step  348 A and a second step  348 B. First step  348 A traverses annular groove  344  and extends axially to second step  348 B. Second step  348 B is disposed radially inward of first step  348 A. An arcuate riser  348 C extends radially outward and faces axially. 
         [0056]    Referring to  FIG. 13 , lock member  330  is shown. Lock member  330  is similar to lock member  130  (shown in  FIG. 5 ) and additionally includes a stiffened deformable annular body  332 , a stiffened first spring finger  334 A, and a stiffened second spring finger  334 B. As used herein, stiffened means that deforming annular body  332 , first spring finger  334 A, and/or second spring finger  334 B requires more force than annular body  132 , first spring finger  134 , and/or second spring finger  136  (each shown in  FIG. 5 ). This may be accomplished, for example, by thickening the respective elements relative to the counterpart elements shown in the embodiment illustrated in  FIG. 5 . 
         [0057]    First spring finger  334 A and second spring finger  334  both include a protrusion  347  (only one indicated in  FIG. 13  for clarity reasons). Protrusion  347  corresponds second step  348 B of stepped axial slot  348  (shown in  FIG. 12 ), and in illustrated exemplary embodiment has an arcuate lip contoured to complement arcuate riser  348 C (shown in  FIG. 12 ) such that arcuate riser  348 C seats in second step  348 B (shown in  FIG. 12 ). This allows for lock member  330  to seat against  340  and remain in an assembled configuration (shown in  FIG. 14 ) prior to installation on a bolt member, simplifying fastening elements and error proofing the installation process. 
         [0058]    Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only exemplary embodiments of the present disclosure are shown and described, simply by way of illustration of the best mode contemplated for carrying out the present disclosure. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. 
         [0059]    The fastening device technology described herein has unlimited application in industry and other uses. Particularly advantageous applications will involve use near motors or moving equipment in which vibration may cause loosening of traditional fasteners such as in automotive applications, aerospace applications, oil and gas, and manufacturing machinery. The present fastening device technology is also well suited for medical applications such as attaching pedicle screws to spinal rods, attaching spinal plates and fracture plates, fixing artificial joints, like hips and knees, orthopedic and maxillofacial external fixator systems, and the like. In particular, those skilled in the art will readily appreciate that embodiments of the fastening device technology described herein can withstand high temperature applications, for example, they can withstand temperatures as high as the material they are fabricated from can tolerate, and are easily applied, removed and reused. In addition, it is contemplated that the tightening of a nut number on a bolt member can be blind. For example, instead of the head portions, flats defined on the bolt member can be held or otherwise fixed during tightening. 
         [0060]    While the subject invention has been described with respect to preferred and exemplary embodiments, those skilled in the art will readily appreciate that various changes and/or modifications can be made to the invention without departing from the spirit or scope of the invention as described herein and as defined by the appended claims.