Abstract:
A floating fastener includes a connection member fastened to a first plate member with a lock screw member, a retaining member installed in a second plate member, a rotary locking device coupled to the connection member and having a locking shank and a shank head with longitudinal cut planes and insertable through the retaining member, a spring member supported between the top wall of the connection member and a step around the periphery of the locking shank, a knob affixed to the top end of the locking shank and operable to bias the locking shank between a locking position where the shank head is forced into engagement with the retaining member and an unlocking position where the shank head is disengaged from the retaining member, and an elastic cushion ring supported between the connection member and the knob.

Description:
[0001]    This application claims the priority benefit of Taiwan patent application number 100118141, filed on May 24, 2011. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to fasteners for joining metal plate members and more particularly, to a floating fastener, which assures locking stability, avoiding accidental disengagement between parts and accidental separation of the first plate member from the second plate member. 
         [0004]    2. Description of the Related Art 
         [0005]    Screws or pins are commonly used many different products for the positioning of movable members. For example, a lock pin may be used to lock a sliding box or board member when the sliding rails of the sliding box or board member are moved relative to respective sliding grooves to a predetermined position, facilitating user&#39;s operation. In a desk computer system, industrial computer system, work station or any other equipment where movable plate members are detachably arranged together, screws or pins may also be used to lock the movable plate members together, facilitating mounting and dismounting. To facilitate detachable installation and to avoid missing component parts, floating fasteners are created. 
         [0006]      FIGS. 9 and 10  illustrate a floating fastener according to the prior art. According to this design, the floating fastener comprises a connection member A, a locking device B consisting of a knob B 1  and a locking shank B 2 , a spring member C and a lock screw D. The lock screw D is inserted through a mounting through hole E 1  of a first plate member E and fastened to the connection member A to affix the connection member A to the first plate member E. The locking shank B 2  has a shank body B 21  upwardly inserted through a top center hole All of the connection member A, and a relatively thicker shank head B 22  located on the bottom end of the shank body B 21  for fastening to a retaining hole F 1  of a second plate member F to lock the first plate member E to the second plate member F. The spring member C is sleeved onto the shank body B 21  of the locking shank B 2  and stopped between the relatively thicker shank head B 22  and the top wall of the connection member A. When locking the first plate member E to the second plate member F, the relatively thicker shank head B 22  is directly and axially forced into engagement with the retaining hole F 1  of the second plate member F. When unlocking the first plate member E from the second plate member F, the relatively thicker shank head B 22  is directly upped upwardly away from the retaining hole F 1  of the second plate member F. This design of floating fastener is still not satisfactory in function. When the second plate member F is pulled by an external force, a shearing force may be produced, causing disconnection of the relatively thicker shank head B 22  from the retaining hole F 1  of the second plate member F. During a wiring work, or transfer or delivery of the equipment, the relatively thicker shank head B 22  may be forced away from the retaining hole F 1  of the second plate member F accidentally, leading to component or equipment damage. 
         [0007]    Therefore, it is desirable to provide a floating fastener that eliminates the aforesaid problem. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention has been accomplished under the circumstances in view. It is therefore an object of the present invention to provide a floating fastener for detachably fastening a first plate member to a second plate member, which assures locking stability, avoiding accidental disengagement between parts and accidental separation of the first plate member from the second plate member. 
         [0009]    To achieve this and other objects of the present invention, a floating fastener comprises a connection member fastened to a first plate member with a lock screw member, a retaining member having a center retaining hole with low inside wall portions, high inside wall portions, positioning grooves and locating grooves and installed in a second plate member, a rotary locking device coupled to the connection member and having a locking shank and a shank head with longitudinal cut planes and a bottom stop flange and insertable through the retaining member, a spring member supported between the top wall of the connection member and a step around the periphery of the locking shank, a knob affixed to the top end of the locking shank and operable to bias the locking shank between a locking position and an unlocking position. 
         [0010]    The shank head of the locking shank is forced into the center retaining hole of the retaining member at the second plate member when the longitudinal cut planes and bottom stop flange of the locking shank are respectively kept in alignment with the low inside wall portions and high inside wall portions of the retaining member. After insertion of the shank head of the locking shank into the center retaining hole of the retaining member, press the knob downwards and rotate the rotary locking device to force the arched faces and bottom stop flange of the locking shank into engagement with the respective positioning grooves and locating grooves, and therefore the second plate member is locked to the first plate member firmly, avoiding accidental disconnection. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an oblique top elevation of a floating fastener in accordance with a first embodiment of the present invention. 
           [0012]      FIG. 2  is an exploded view of the floating fastener in accordance with the first embodiment of the present invention. 
           [0013]      FIG. 3  corresponds to  FIG. 2  when viewed from another angle. 
           [0014]      FIG. 4  is a sectional side view of the floating fastener in accordance with the first embodiment of the present invention. 
           [0015]      FIG. 5  is a schematic sectional applied view of the first embodiment of the present invention, illustrating the floating fastener fastened to the first metal plate member before installation of the retaining member in the second plate member. 
           [0016]      FIG. 6  corresponds to  FIG. 5 , illustrating the retaining member installed in the second plate member. 
           [0017]      FIG. 7  corresponds to  FIG. 6 , illustrating the rotary locking device fastened to the retaining member at the second plate member. 
           [0018]      FIG. 8  is a sectional view of a floating fastener in accordance with a second embodiment of the present invention. 
           [0019]      FIG. 9  is an exploded view of a floating fastener according to the prior art. 
           [0020]      FIG. 10  is a sectional view of the floating fastener according to the prior art. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0021]    Referring to  FIGS. 1-5 , a floating fastener in accordance with a first embodiment of the present invention is shown comprising a connection member  1 , a rotary locking device  2 , a spring member  3 , an elastic cushion ring  31 , a lock screw member  4  and a retaining member  5 . 
         [0022]    The connection member  1  comprises a tubular body  11  having a bottom open chamber  13 , an embossed positioning portion  12  located on the bottom edge thereof around the bottom open side of the bottom open chamber  13 , a top center hole  132  located on the top side thereof in communication with the bottom open chamber  13 , and an inner thread  131  spirally extending around an inside wall thereof in the bottom open chamber  13 . 
         [0023]    The rotary locking device  2  comprises a knob  21  disposed above the connection member  1 , and a locking shank  22  connected to the knob  21  and inserted through the top center hole  132  and the bottom open chamber  13  of the connection member  1 . The knob  21  has a plurality of vertical tooth grooves  211  spaced around the periphery thereof, a bottom recess  213  located on the center of the bottom wall thereof and a bottom mounting hole  212  located on the center of the bottom recess  213 . The locking shank  22  has a plain shank body  221 , a top mounting portion  223  located on one end of the plain shank body  221  and riveted to the bottom mounting hole  212  of the knob  21 , a shank head  222  located on the other end of the plain shank body  221  and a step  2211  connected between the plain shank body  221  and the shank head  222 . The shank head  222  has a diameter greater than the plain shank body  221 , two longitudinal cut planes  2221  and two arched faces  2222  alternately spaced around the periphery and abutted against one another, and a bottom stop flange  2223  extending around the bottom end thereof beyond the longitudinal cut planes  2221  remote from the plain shank body  221 . 
         [0024]    The spring member  3  is sleeved onto the locking shank  22  of the rotary locking device  2 , having its one end stopped against an inside part of the tubular body  11  of the connection member  1  around the top center hole  132  and its other end stopped against the step  2211  of the rotary locking device  2 . 
         [0025]    The elastic cushion ring  31  is elastically compressibly set in between the bottom recess  213  of the knob  21  and the top wall of the connection member  1  around the top center hole  132 . 
         [0026]    The lock screw member  4  comprises a screw tube  42  threaded into the inner thread  131  of the connection member  1 , a screw head  41  radially outwardly extending around the periphery of the bottom end of the screw tube  42  and an axial hole  421  surrounded by the screw tube  42 . 
         [0027]    The retaining member  5  comprises a center retaining hole  50  cut through top and bottom sides thereof, an embossed engagement portion  51  located on the top side around the center retaining hole  50  for positioning in a mounting through hole  71  of a second late member  7 , two high inside wall portions  52  and two low inside wall portions  53  alternatively arranged around the center retaining hole  50  and connected to one another in a flush manner corresponding to the longitudinal cut planes  2221  and two arched faces  2222  of the locking shank  22  of the rotary locking device  2 , two positioning grooves  531  respectively located on the low inside wall portions  53  and two locating grooves  532  located on the bottom side of the retaining member  5  corresponding to the positioning grooves  531 . 
         [0028]    Referring to  FIGS. 4˜7  and  FIGS. 2 and 3  again, during installation of the floating fastener, insert the top mounting portion  223  of the locking shank  22  upwardly in proper order through the spring member  3 , the bottom open chamber  13  and top center hole  132  of the connection member  1  and the elastic cushion ring  31 , and the riveting the top mounting portion  223  to the bottom mounting hole  212  of the knob  21 . At this time, the spring member  3  is received in the bottom open chamber  13  of the connection member  1  and stopped the inner surface of the top wall of the tubular body  11  of the connection member  1  around the top center hole  132  and the step  2211  of the rotary locking device  2 , and the elastic cushion ring  31  is accommodated in the bottom recess  213  of the knob  21 . Thereafter, attach the embossed positioning portion  12  of the connection member  1  to the top wall of a first plate member  6  around a mounting through hole  61 , and then insert the screw tube  42  of the lock screw member  4  upwardly through the mounting through hole  61  of the first plate member  6  and thread the screw tube  42  into the inner thread  131  of the connection member  1  to lock the connection member  1  to the first plate member  6 . When attaching the second plate member  7  to the first plate member  6  to keep the center retaining hole  50  of the retaining member  5  that is affixed to the mounting through hole  71  of the second plate member  7  in alignment with the mounting through hole  61  of the first plate member  6 , the spring member  3  imparts an outward pressure to the step  2211  to force the shank head  222  of the locking shank  22  into the center retaining hole  50  of the retaining member  5  at the second plate member  7 . At this time, the longitudinal cut planes  2221  and bottom stop flange  2223  of the locking shank  22  are respectively aimed at the low inside wall portions  53  and the high inside wall portions  52  of the retaining member  5  for allowing the shank head  222  to enter the center retaining hole  50 . Thereafter, press the knob  21  to compress the elastic cushion ring  31  against the connection member  1  to force the shank head  222  to enter the center retaining hole  50 . After the bottom stop flange  2223  passed downwardly over the bottom side of the second plate member  7 , rotate the rotary locking device  2  through 90° angle to force the arched faces  2222  into the positioning grooves  531  respectively. After the user released the hand from the knob  21 , the elastic cushion ring  31  immediately returns to its former shape, causing the bottom stop flange  2223  of the locking shank  22  to be forced into engagement with the locating grooves  532 , enhancing locking tightness and avoiding accidental disengagement of the shank head  222  of the locking shank  22  from the center retaining hole  50  of the retaining member  5  at the second plate member  7 . 
         [0029]    When going to detach the second plate member  7  from the first plate member  6 , press the knob  21  to compress the elastic cushion ring  31  against the connection member  1  and to move the bottom stop flange  2223  of the locking shank  22  downwardly away from the locating grooves  532 , and then rotate the rotary locking device  2  through 90° angle to move the arched faces  2222  away from the respective positioning grooves  531  and simultaneously to move the shank head  222  of the locking shank  22  into axial alignment with the longitudinal cut planes  2221  and the bottom stop flange  2223  into axial alignment with into axial alignment with the high inside wall portions  52 , enabling the shank head  222  to be retracted into the center retaining hole  50 . When released the pressure from the rotary locking device  2  at this time, the spring member  3  returns to its former shape, and therefore the second plate member  7  is unlocked from the first plate member  6  and can be moved away freely. 
         [0030]      FIG. 8  illustrates an alternate form of the present invention. This second embodiment is substantially similar to the aforesaid first embodiment with the exception that the retaining member  5  is eliminated, and the mounting through hole  71  of the second plate member  7  is designed subject to the structure of the retaining member  5 , i.e., the second plate member  7  comprises two high inside wall portions  72  and two low inside wall portions  73  alternatively arranged around the mounting through hole  71  and connected to one another in a flush manner corresponding to the longitudinal cut planes  2221  and two arched faces  2222  of the locking shank  22  of the rotary locking device  2 , two positioning grooves  731  respectively located on the low inside wall portions  73  and two locating grooves  732  located on the bottom side of the second plate member  7  corresponding to the positioning grooves  531 . 
         [0031]    In general, the invention provides a floating fastener for detachably fastening the second plate member  7  to the first plate member  6 . Subject to the spring force of the spring member  3 , the shank head  222  of the locking shank  22  is forced into the center retaining hole  50  of the retaining member  5  at the second plate member  7  when the longitudinal cut planes  2221  and the bottom stop flange  2223  of the locking shank  22  are respectively kept in alignment with the high inside wall portions  52  and the low inside wall portions  53  of the retaining member  5 . After insertion of the shank head  222  of the locking shank  22  into the center retaining hole  50  of the retaining member  5  at the second plate member  7 , press the knob  21  downwards and rotate the rotary locking device  2  to force the arched faces  2222  and the bottom stop flange  2223  of the locking shank  22  into engagement with the positioning grooves  531  and the locating grooves  532  respectively, and therefore the second plate member  7  is locked to the first plate member  6  firmly. Further, the shank head  222  can be made having one single longitudinal cut plane  2221  or two longitudinal cut planes  2221 , and the retaining member  5  can be made having one single low inside wall portion  53  or two inside wall portions  53 , achieving the same effects. 
         [0032]    Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention.