Patent Publication Number: US-2011070046-A1

Title: Metal plate member fixation device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a metal plate member fixation device for joining two metal plate members and more particularly, to a low-profile metal plate member fixation device, which is formed of a locking device, a barrel, a spring member and a stop washer, wherein the stop washer secures the lock screw bolt of the locking device to the barrel, allowing axial movement of the lock screw bolt relative to the barrel within a predetermined range and prohibiting escape of the lock screw bolt from the barrel. 
     2. Description of the Related Art 
     When fastening two plate members together, a positioning screw formed of a knob, a ring and a screw nail is usually used. During installation, the screw nail and the ring are secured to the first plate member, and then the knob is rotated to drive the screw nail into the second plate member, and then a hand tool is used to fasten tight the screw nail, affixing the first and second plate members together. This plate member joining method can be used in a machine tool to join plate members together. 
     The power drive and speed-adjustment unit of a machine tool are generally provided inside the housing. To facilitate repair of a machine tool or adjustment of the output speed of a machine tool, a detachable plate member is usually provided at the housing of the power drive or speed-adjustment unit. Screw bolts are commonly used to fasten the movable plate member to the housing. When unfastening screw bolts to dismount a movable plate member from the housing, the associating lock nuts may fall from the screw bolts. This movable plate member mounting and dismounting procedure is complicated, wasting much time and labor. 
     There is known a metal plate member fixation device comprised of a cap, a screw bolt, a spring member and a locating base for joining two metal plate members together. After fixation of the locating base of the metal plate member fixation device to a through hole on a first plate member, the screw bolt is threaded into a screw hole on a second plate member to secure the first plate member and the second plate member together. Because the locating base of the metal plate member fixation device is kept secured to the first plate member after removal of the first plate member from the second plate member, the metal plate member fixation device will not be missed by accident. According to this design, the cap is a metal member. After the screw bolt is accommodated in the cap, a machine tool is used to process the cap so that retaining protrusions are formed on the cap and forced into engagement with the screw bolt. This processing process requires high precision and wastes time and labor. During processing, the cap may be compressed excessively, resulting in permanent deformation. 
     Therefore, it is desirable to provide a metal plate member fixation device that eliminates the aforesaid problems. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is therefore an object of the present invention to provide a metal plate member fixation device for joining metal plate members, which facilitates installation and presents disconnection between component parts. 
     To achieve these and other objects of the present invention, a metal plate member fixation device comprises a barrel for bonding to a first metal plate member, a locking device, which comprises a lock screw bolt axially slidably coupled to the barrel for inserting through a mounting through hole on the first metal plate member and threading into a screw hole on a second metal plate member to lock the first metal plate member and the second metal plate member together and a cap affixed to the head of the lock screw bolt for gripping, a spring member sleeved onto the shank of the lock screw bolt inside the cap and stopped against the head of the lock screw bolt, and a stop washer set in an annular inside locating groove inside the barrel around the shank of the lock screw bolt and stopped against the other end of the spring member for stopping against one end of the thread of the lock screw bolt to prohibit escape of the lock screw bolt of the locking device from the barrel. By means of the application of the stop washer, the height (length) of the spring member can be minimized so that the metal plate member fixation device can have a low profile characteristic for easy, quick and accurate installation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational view of a metal plate member fixation device in accordance with the present invention. 
         FIG. 2  is an exploded view of the metal plate member fixation device in accordance with the present invention. 
         FIG. 3  is an exploded view in sectional elevation of the metal plate member fixation device in accordance with the present invention. 
         FIG. 4  is a sectional assembly view of the metal plate member fixation device in accordance with the present invention (I). 
         FIG. 5  is a sectional assembly view of the metal plate member fixation device in accordance with the present invention (II). 
         FIG. 6  is a sectional assembly view of the metal plate member fixation device in accordance with the present invention (III). 
         FIG. 7  is a schematic sectional applied view of the present invention, showing the barrel of the metal plate member fixation device bonded to a first metal plate member. 
         FIG. 8  corresponds to  FIG. 7 , showing the first metal plate member attached to the second metal plate member and the lock screw bolt of the locking device fastened to the screw hole of the second metal plate member. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1˜4 , a metal plate member fixation device in accordance with the present invention is shown comprising a locking device  1 , a barrel  2 , a spring member  3 , and a stop washer  4 . 
     The locking device  1  comprises a cap  11  and a lock screw bolt  12 . The cap  11  is a hollow member having a center opening  110  axially extending through the top and bottom sides for receiving the barrel  2 , the lock screw bolt  12  and the spring member  3 , a mounting groove  111  extending around the inside wall thereof in one end of the center opening  110  and a grip  112  located on the periphery for gripping by hand. The lock screw bolt  12  is a metal screw bolt having a head  121  fitting the mounting groove  111  of the cap  11 , a shank  122  perpendicularly extended from the center of the bottom wall of the head  121 , a thread  123  spirally extending around the periphery of one end of the shank  122  remote from the head  121  and a tool groove  1211  located on the top wall of the head  121 . 
     The barrel  2  is a hollow cylindrical metal member having a mounting hole  20  extending through top and bottom sides thereof for the passing of the shank  122  of the lock screw bolt  12 , an annular inside locating groove  21  extending around the inside wall thereof near one end of the mounting hole  20 , a sloping inside wall portion  22  gradually increasing in diameter in direction from the annular inside locating groove  21  toward the other end of the mounting hole  20 , a bottom bonding wall  24  located on the bottom side around the mounting hole  20  and a bottom extension tube  23  perpendicularly extended from the bottom bonding wall  24  around the mounting hole  20 . 
     The spring member  3  is sleeved onto the lock screw bolt  12 , having one end thereof stopped against the head  121  of the lock screw bolt  12  and the other end thereof inserted into the mounting hole  20  of the barrel  2 . 
     The stop washer  4  is inserted into the mounting hole  20  of the barrel  2  and engaged in the annular inside locating groove  21  of the barrel  2 , having a top bearing surface  41  for supporting one end of the spring member  3  and a bottom stop surface  42  for stopping against one end of the thread  123  of the lock screw bolt  12  to prohibit escape of the lock screw bolt  12  from the barrel  2  after the metal plate member fixation device has been assembled. 
     The aforesaid lock screw bolt  12  is made of metal. The cap  11  can be directly molded on the head  121  of the lock screw bolt  12  with over-molding technology. Alternatively, the cap  11  can be separately made and then affixed to the lock screw bolt  12  by means of any of a variety of fastening techniques. In this case, male engagement means, such as barbs, threads or teeth, may be formed on the periphery of the head  121  of the lock screw bolt  12  for engagement with the mounting groove  111  of the cap  11 . When the cap  11  and the lock screw bolt  12  are molded or fastened together, a user can drive the grip  112  to rotate the lock screw bolt  12  into the workpiece. The stop washer  4  can be made from brass, zinc alloy, aluminum or any other metal materials having high extensibility. Alternatively, a C-shaped retainer ring can be used to substitute for the stop washer  4 . 
     Referring to  FIGS. 5 and 6  and  FIGS. 1˜4  again, during assembly process of the metal plate member fixation device, sleeve the spring member  3  onto the shank  122  of the lock screw bolt  12  to have one end of the spring member  3  be stopped at the bottom side of the head  121  of the lock screw bolt  12 , and then insert the barrel  2  into the center opening  110  of the cap  11  around the spring member  3  and the shank  122  of the barrel  2  against the other end of the spring member  3 , and then use a tool to insert the stop washer  4  into the mounting hole  20  of the barrel  2  and to further force the stop washer  4  inwardly along the sloping inside wall portion  22  over the thread  123  of the lock screw bolt  12  against the spring member  3  into the annular inside locating groove  21  of the barrel  2 . After the stop washer  4  has been positioned in the annular inside locating groove  21  of the barrel  2 , the top bearing surface  41  of the stop washer  4  is stopped against one end of the spring member  3  and the bottom stop surface  42  of the stop washer  4  is stopped against one end of the thread  123  of the lock screw bolt  12  to prohibit escape of the lock screw bolt  12  from the barrel  2 . Thus, the lock screw bolt  12  is axially movably coupled to the barrel  2  and the stop washer  4  for installation. 
     Further, when assembling the lock screw bolt  12  and the barrel  2 , the spring member  3  is stopped against the stop washer  4  and the stop washer  4  is forced into the annular inside locating groove  21  of the barrel  2  for stopping against one end of the thread  123  of the lock screw bolt  12 . By means of the application of the stop washer  4 , the height (length) of the spring member  3  can be minimized so that the metal plate member fixation device can have a low profile characteristic for easy, quick and accurate installation. 
     Referring to  FIGS. 7 and 8 , during application, press-fit the bottom extension tube  23  of the barrel  2  into a mounting through hole  51  of a first metal plate member  5  to attach the bottom bonding wall  24  of the barrel  2  to the solder paste  52  being applied to the border area of the mounting through hole  51  of the first metal plate member  5 . Alternatively, an automatic installation machine can be used to pick up the metal plate member fixation device and then to insert the bottom extension tube  23  of the barrel  2  of the metal plate member fixation device into the mounting through hole  51  of the first metal plate member  5  tightly. Thereafter, a reflow soldering process is applied to bond the barrel  2  to the first metal plate  5 . 
     After installation of the barrel  2  in the first metal plate member  5 , attach the first metal plate member  5  to a second metal plate member  6  to keep the mounting through hole  51  of the first metal plate member  5  in alignment with one screw hole  61  of the second metal plate member  6 , and then force the cap  11  downwards and rotate the grip  112  of the cap  11  to drive the outer thread  123  of the lock screw bolt  12  into the screw hole  61  of the second metal plate member  6 , and then attach a hand tool (for example, screwdriver) to the tool groove  1211  of the head  121  of the lock screw bolt  12  and rotate the hand tool to tighten up the connection between the lock screw bolt  12  and the second metal plate member  6 . Thus, the first metal plate member  5  and the second metal plate member  6  are locked together. When wishing to dismount the first metal plate member  5  from the second metal plate member  6 , rotate the cap  11  in the reversed direction to disengage the thread  123  of the lock screw  12  from the screw hole  61  of the second metal plate member  6 , allowing removal of the first metal plate member  5  from the second metal plate member  6 . 
     Further, the stop washer  4  can be made in the form of a flat retaining ring or C-shaped retainer ring. Further, the stop washer  4  is positioned in the annular inside locating groove  21  of the barrel  2 , having the top bearing surface  41  thereof stopped against one end of the spring member  3  and the bottom stop surface  42  thereof disposed for stopping against the thread  123  of the lock screw bolt  12  to prohibit escape of the lock screw bolt  12  from the barrel  2 . By means of the application of the stop washer  4 , the height (length) of the spring member  3  can be minimized so that the metal plate member fixation device can have a low profile characteristic. 
     A prototype of metal plate member fixation device has been constructed with the features of  FIGS. 1˜8 . The metal plate member fixation device functions smoothly to provide all of the features disclosed earlier. 
     Although a particular embodiment of the invention has 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. Accordingly, the invention is not to be limited except as by the appended claims.