Patent Publication Number: US-2007110511-A1

Title: Coupling mechanism for connecting board-type shelf to vertical post of a sectional rack

Description:
FIELD OF THE INVENTION  
      The present invention relates to a coupling mechanism for connecting a board-type shelf to a vertical post of a sectional rack, and more particularly to a coupling mechanism that is invisibly mounted to each lower corner of a board-type shelf to connect the shelf to a post of a sectional rack, giving the whole rack a high quality appearance.  
     BACKGROUND OF THE INVENTION  
      A sectional rack has become indispensable in many houses, offices, and open-shelf stores because it can be easily assembled, disassembled, transported, and stored.  
      There are many types of sectional racks that could be assembled and erected without using any fastening elements, such as the sectional rack using bamboo-like vertical posts. U.S. Pat. Nos. 5,676,263; 5,303,645; 5,174,676; 4,991,725; 4,799,818; 4,595,107; 4,546,887; and 4,763,799 all disclose structures in connection with sectional racks using the bamboo-like vertical posts.  
      Most of the shelves for the sectional racks using the bamboo-like vertical posts are made of metal wires or flat boards. The shelf made of metal wires has rather weak structural strength, and includes a plurality of through holes, via which articles positioned on the shelf might very possibly drop. The sectional rack using the metal wire shelves is less beautiful in its appearance, too. The board-type shelf has a flat and smooth top surface for stably holding articles thereon, and has beautiful appearance. To assemble the board-type shelf to the vertical posts, conic sleeves must be provided to all corners of the shelf. The conic sleeves spoil the integrity of the shelf and make the whole rack looked ugly and unable to meet the general consumers&#39; requirement.  
     SUMMARY OF THE INVENTION  
      A primary object of the present invention is to provide a coupling mechanism for connecting a board-type shelf to a vertical post of a sectional rack without protruding any connecting elements thereof from the shelf, so that the whole rack presents a beautiful and high quality appearance.  
      The coupling mechanism of the present invention includes a coupling device that is fitted in a groove preformed at each lower corner of the shelf to flush with a bottom surface of the shelf, enabling the shelf before being connected to the post to have completely flat and smooth top, bottom, and side surfaces to facilitate convenient storage and transport of the shelf.  
      In addition to the coupling device, the coupling mechanism of the present invention further includes a hanger that has a front engaging head located in the coupling device and a hooked rear end hung on connecting holes on the post. By mounting the coupling device at each lower corner of the shelf to couple to the hanger on a corresponding vertical post, the shelf can be connected to and supported on the vertical posts to provide a rack.  
      The coupling device includes a tightness control element, in which the engaging head of the hanger is located; and an adjusting unit adapted to change a position of the tightness control element relative to the hanger, so that the tightness control element may be loosened from or tightened against the engaging head of the hanger to facilitate easy removal or connection of the shelf from or to the vertical post.  
      The adjusting unit includes a slide located in the tightness control element, and an adjusting screw threaded through the slide. When the adjusting screw is turned, the slide is moved up or down to bring the tightness control element to loosen from or tighten against the engaging head of the hanger. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein  
       FIG. 1  is a fragmentary bottom perspective view showing a board-type shelf connected to a vertical post of a rack using the coupling mechanism of the present invention;  
       FIG. 2  is an exploded view of  FIG. 1 ;  
       FIG. 3  is a bottom perspective view showing a coupling device of the coupling mechanism of the present invention before being mounted to a bottom side of the board-type shelf;  
       FIG. 4  is a complete bottom perspective view showing a board-type shelf is connected at four lower corners to four vertical posts using the coupling mechanism of the present invention;  
       FIG. 5  is an exploded bottom perspective view of the coupling device included in the coupling mechanism of the present invention;  
       FIG. 6  is a cross-sectional view of  FIG. 1  showing the coupling device of the present invention mounted to the lower corner of the board-type shelf is in a loosened position relative to a hanger hooked on the vertical post; and  
       FIG. 7  is similar to  FIG. 6  but showing the coupling device of the present invention mounted to the lower corner of the board-type shelf is in a tightened position relative to the hanger on the vertical post. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Please refer to  FIGS. 1 and 4  that are fragmentary and complete assembled bottom perspective views, respectively, showing a board-type shelf  10  is connected at each lower corner to a vertical post  30  of a sectional rack using a coupling mechanism of the present invention; and to  FIG. 2  that is an exploded view of  FIG. 1 . As can be clearly seen from  FIG. 2 , the coupling mechanism includes a coupling device  20  mounted at each lower corner of the shelf  10 , and a hanger  40 .  
      The vertical post  30  is symmetrically provided on two opposite sides with a row of connecting holes  31  each. The hanger  40  is hung onto the vertical post  30  by extending two vertically spaced hooks  41  provided at a rear end of the hanger  40  into two vertically adjacent connecting holes  31  on the post  30 . An engaging head  42  is provided at a front end of the hanger  40 .  
      The board-type shelf  10  is provided at each lower corner with one coupling device  20 , which is adapted to couple to the engaging head  42  of the hanger  40  hung on the vertical post  30 .  
      Please refer to  FIG. 3  that is a bottom perspective view showing the coupling device  20  of the present invention before being mounted to the lower corner of the board-type shelf  10 , and to  FIG. 5  that is an exploded bottom perspective view of the coupling device  20 . As shown, the coupling device  20  includes a locating unit  21 , a tightness control element  22 , and an adjusting unit  23 .  
      As can be seen from  FIG. 3 , the locating unit  21  is firmly fitted in a groove  11  preformed at the lower corner of the board-type shelf  10  using a screw  12 , and includes a base plate  211 , which is fitted in the groove  11 , and a cover plate  212  for closing an open lower side of the groove  11 . Please refer to  FIG. 5 . In the illustrated embodiment of the present invention, the base plate  211  is provided at two opposite lateral sides of an outer end facing toward the post  30  with two downward extended and slightly inward bent tabs  213 . It is noted the groove  11  preformed at the bottom side of the shelf  10  is a dovetail groove having a cross section corresponding to that of the base plate  211  at the two tabs  213  (see  FIG. 3 ). When the base plate  211  is inserted into the groove  11 , the two tabs  213  fitly bear against an inner wall surface of the groove  11 , allowing the base plate  211  to stably and tightly locate in the groove  11 . The cover plate  212  has an overall width and an overall length slightly larger than those of the base plate  211 , and can be fitly set in a shallow recessed area  13  formed at the bottom of the shelf  10  around the groove  11 . The cover plate  212  is locked to the shallow recessed area  13  by the screw  12 . The base plate  211  and the cover plate  212  of the locating unit  21  together define at the outer end a side opening  214  oriented to one side of the shelf  10  facing toward the post  30 , and at a central area between them a hollow space for receiving the tightness control element  22  therein. The cover plate  212  is provided near the outer end with a window  215  to communicate with the side opening  214 .  
      The tightness control element  22  is a lying U-shaped member formed from a flat plate to include a side opening  221  at an outer end thereof. Two sidewalls of the lying U-shaped tightness control element  22  are substantially parallelly extended from a closed top at an inner end of the element  22  by a predetermined distance and then tapered toward the side opening  221 , so that two inclined inner wall surfaces  222  are formed immediately behind the side opening  221 . Two downward and outward inclined oblique guide slots  223  are symmetrically formed on the parallel portion of the two sidewalls of the control element  22  near the closed top thereof.  
      Please refer to  FIG. 6  that is a cross-sectional view of  FIG. 1  showing the coupling device  20  mounted to the lower corner of the board-type shelf  10  is coupled to the engaging head  42  at the front end of the hanger  40 , and the two hooks  41  at the rear end of the hanger  40  are connected to the connecting holes  31  on the post  30 . The engaging head  42  of the hanger  40  has a cross section tapered from the front end toward the rear end of the hanger  40 , and is shaped and dimensioned corresponding to a space in an outer part of the tightness control element  22  immediately behind the side opening  221 . The coupling device  20  is connected to the hanger  40  by moving the engaging head  42  of the hanger  40  into the hollow central space of the tightness control element  22  via the window  215  on the cover plate  212  of the locating unit  21 .  
      Please refer back to  FIGS. 3 and 5 . The adjusting unit  23  includes an adjusting screw  231  mounted on the locating unit, and a slide  232 . The slide  232  includes a centered, vertically extended, and internally threaded hole  233  and two opposite, horizontally outward extended shafts  234 . The slide  232  is located between the two parallel sidewalls of the tightness control element  22  with the two opposite horizontal shafts  234  separately movably seated in the two oblique guide slots  223  on the element  22 . The adjusting screw  231  is upward threaded through the cover plate  212 , the internally threaded vertical hole  233  on the slide  232 , and the base plate  211  to be pivotally turnable about an axis of the slide  232 . When the adjusting screw  231  is turned, the slide  232  is caused to move up or down along the two oblique guide slots  223  on the tightness control element  22  and thereby brings the latter to move toward the inner end or the outer end of the groove  11 . In the illustrated embodiment of the present invention, when the adjusting screw  231  is turned clockwise, the tightness control element  22  is brought to move toward the inner end of the groove  11  and therefore presses the two inclined inner wall surfaces  222  against the engaging head  42  of the hanger  40  hung on the post  30 , as shown in  FIG. 7 . At this point, the tightness control element  22  tightly pulls the engaging head  42  of the hanger  40  for the whole coupling device  20  to firmly couple to the hanger  40  and for the board-type shelf  10  to stably connect to the post  30 . And, when the adjusting screw  231  is turned counterclockwise, the tightness control element  22  is brought to move toward the outer end of the groove  11 , as shown in  FIG. 6 . At this point, the two inclined inner wall surfaces  222  of the tightness control element  22  no longer tightly press against the engaging head  42  of the hanger  40 , allowing the board-type shelf  10  to be easily removed from the post  30 .  
      For easy operation, words with arrows showing different operational directions, such as “close” and “open”, may be marked on the cover plate  212 , as shown in  FIG. 5 . The two horizontal shafts  234  provided at two opposite sides of the slide  232  may be two screws symmetrically threaded into the two opposite sides of the slide  232 . Meanwhile, to facilitate easy mounting of the slide  232  in the tightness control element  22 , the length of the two horizontal shafts  234  projected from the two opposite sides of the slide  232  may adjusted by changing the depth by which the two screws are threaded into the slide  232 .  
      The tightness control element  22  is located in the central hollow space of the locating unit  21  with the side opening  221  located in the side opening  214  at the outer end of the locating unit  21 , such that the side opening  221  of the tightness control element  22  is restrained from expanding due to a fixed openness of the side opening  214  of the locating unit  21 . After the engaging head  42  of the hanger  40  is moved into the tightness control element  22  via the window  215  on the cover plate  212  of the locating unit  21 , the adjusting screw  231  may be turned in a correct direction to allow connecting of the board-type shelf  10  to the post  30 .  
      Please refer back to  FIG. 5 . The cover plate  212  of the locating unit  21  is provided at two lateral sides of the window  215  near the side opening  214  with an upward extended tab  216  each. When the cover plate  212  is closed to a lower side of the base plate  211 , the two upward tabs  216  are adapted to fitly bear against the inner side of the two downward tabs  213  of the base plate  211 , as shown in  FIG. 6 , and a distance between the two upward tabs  216  defines the openness of the side opening  214  of the locating unit  21 . Moreover, the tightness control element  22  is provided at a top of each sidewall adjacent to the side opening  221  with a sideward projected wing portion  224 , which serves as a means to prevent the tightness control element  22  from moving sideward in the locating unit  21 .  
      As can be seen from  FIG. 4 , the coupling device  20  is mounted to each lower corner of the board-type shelf  10  to couple to the engaging head  42  of the hanger  40  hung on the post  30 . When the adjusting screws  231  of all the coupling devices  20  below one shelf  10  are sequentially turned clockwise, all the tightness control elements  22  in the coupling devices  20  are caused to tightly press against the engaging heads  42  of the hangers  40 , allowing the board-type shelf  10  to be firmly and stably connected to and supported on the posts  30 .  
      It is noted the coupling device  20  of the present invention is set in the groove  11  formed at each lower corner of the board-type shelf  10  to flush with a bottom surface of the shelf  10 . In this manner, the shelf  10  does not have any member protruded from its top, bottom, and all side surfaces, and would have a volume as small as possible to occupy a minimum space for storage and transport. Moreover, the board-type shelf  10  connected to the posts  30  advantageously shields the hangers  40 , giving the rack fully assembled from the posts  30  and the shelves  10  a high quality appearance without any exposed connecting members.