Abstract:
An auto-locking structure used in a sliding track assembly for drawer is constructed to include a track located on the rear side of the outer sliding rail of the sliding track assembly, a sliding locking block sliding in the track and adapted to alternatively lock the inner sliding rail between the extended and received positions, and a tensile spring connected between the track and sliding locking block, the sliding locking block having a side locating hole defined between a sloping wall and a stop wall and an opening adjacent to the side locating hole for positively secure the inner sliding rail in the extended or received position.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to a sliding track assembly for drawer and, more specifically, to an auto-locking structure used in a sliding track assembly for drawer. 
     FIG. 1 illustrates an auto-locking structure used in a sliding track assembly for drawer according to the prior art. According to this design, the auto-locking structure comprises a seat  911 , a spring member  912  and a link  913  respectively installed in the outer sliding rail  91 , and an engagement block  921  installed in the inner sliding rail  92 . This design of auto-locking structure is not satisfactory in function. Because the seat  911  occupies much rear side space of the outer sliding rail  91 , it weakens the functioning of the outer sliding rail  91  to bear the load. 
     It is the main object of the present invention to provide an auto-locking structure for use in a sliding track assembly for drawer, which requires less installation space in the sliding track assembly. It is another object of the present invention to provide an auto-locking structure for use in a sliding track assembly, which does not weaken the functioning of the sliding track assembly to bearing the load. According to one aspect of the present invention, the auto-locking structure comprises a track fastened to the outer sliding rail of the sliding track assembly, a sliding locking block movably supported in the track, a spring member connected between the track and the sliding locking block, and a push block located on the inner sliding rail of the sliding track assembly. The track provides a sliding groove formed of a linear front sliding groove portion and a arched rear sliding groove portion and a hook hole biased from the front side of the linear front sliding groove portion to match the sliding locking block. The sliding locking block has a locating rod, a sloping wall, and a side locating hole. The push block has a push rod adapted to mach the sliding locking block to achieve an auto-locking action. Because the track and the sliding locking block have a limited size, they occupy small installation space in the outer sliding rail without affecting the functioning of the sliding track assembly to carry the load. According to another aspect of the present invention, when the inner sliding rail pushed backwards to force the back sidewall of the sliding locking block against the front sidewall of the first locating block of the track, the rear end of one lateral sidewall of the inner sliding rail is automatically forced into engagement with a clamping portion of the first locating block of the track, and therefore the inner sliding rail is positively held in position. According to still another aspect of the present invention, the sliding locking block has an opening adjacent to the sloping wall and the side locating hole, such that the sloping wall of the sliding locking block can be deformed by the push rod of the push block for enabling the push rod to move into the side locating hole to achieve an locking action when the sliding locking block forced by an unexpected external force and pulled backwards by the spring member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view of the prior art design. 
     FIG. 2 is an exploded view of the preferred embodiment of the present invention. Showing the inner sliding rail detached from the intermediate sliding rail. 
     FIG. 3 is an elevational assembly view of the present invention. 
     FIG. 4 is an exploded view of the push block and the inner sliding rail according to the present invention. 
     FIG. 5 is an assembly view of FIG.  4 . 
     FIG. 6 is an exploded view of the present invention, showing the track, the tensile spring, and the sliding locking block detached from the sliding track assembly. 
     FIG. 7 is an enlarged view of a part of FIG.  6 . 
     FIG. 8 is an oblique top elevation of the track shown in FIG.  7 . 
     FIG. 9 is an oblique bottom elevation of the track shown in FIG.  7 . 
     FIG. 10 is an oblique top elevation of the sliding locking block shown in FIG.  7 . 
     FIG. 11 is an oblique bottom elevation of the sliding locking block shown in FIG.  7 . 
     FIG. 12 is an oblique top elevation in an enlarged scale of the push block shown in FIG.  2 . 
     FIG. 13 is an oblique bottom elevation in an enlarged scale of the push block shown in FIG.  2 . 
     FIG. 14 is a top plain view of the present invention showing the push block moved with the inner sliding rail away from the sliding locking block. 
     FIG. 15 is a top plain view of the present invention showing the push rod of the push block forced into engagement with the sliding locking block. 
     FIG. 16 is a top plain view of the present invention showing the inner sliding rail pushed backwards and forced into engagement with the clamping portion of the first locating block of the track. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to Figures from  2  through  16 , an auto-locking structure in accordance with the present invention is used in a sliding track assembly for drawer. The sliding track assembly comprises an outer sliding rail  2 , an intermediate sliding rail  7 , an inner sliding rail  1 , a first ball bearing plate (not shown) provided between the outer sliding rail  2  and the intermediate sliding rail  7 , and a second ball bearing plate  82  provided between the intermediate sliding rail  7  and the inner sliding rail  2 . The outer sliding rail  2  is fixedly fastened to the inner sidewall of the desk (not shown) at one side of the drawer receiving space. The inner sliding rail  1  is fixedly fastened to one vertical side panel of the drawer (not shown), for enabling the drawer to be moved in and out of the drawer receiving space within the desk. The drawer can be detached with the inner sliding rail  1  from the intermediate sliding rail  7  and the outer sliding rail  2 . The intermediate sliding rail  7  comprises a locating block  71  in the outer end. The locating block  71  has a protruded engagement portion  712 . The inner sliding rail  1  comprises a retaining strip  12  for detachably engaging the protruded engagement portion  712  of the locating block  71  of the intermediate sliding rail  7 . 
     The auto-locking structure is comprised of a push block  4 , a sliding locking block  5 , a tensile spring  50 , and a track  6 . The push block  4  has an insert portion  43  press-fitted into a locating hole  19  in the rear end of the inner sliding rail  1 , and a mounting hole  41  fixedly fastened to the inner sliding rail  1  by a fastening element  44 . The sliding locking block  5  is fastened to one end  501  of the tensile spring  50 . The track  6  is fixedly fastened to the outer sliding rail  2  near its rear end. When the drawer moved with the inner sliding rail  1  backwards to the inside of the drawer receiving space of the desk, the push block  4  pushes the sliding locking block  5  backwards to the locking position. 
     The main features of the present invention are outlined hereinafter. The track  6  comprises a sliding groove  61  formed of a linear front sliding groove portion  611  and an arched rear sliding groove portion  612  (see FIG.  9 ), a low stop wall  62  extended along one side of the linear front sliding groove portion  611 , a first locating block  64  at the rear side of the low stop wall  62  adjacent to the arched rear sliding groove portion  612 , a clamping portion  641  protruded from one side of the first locating block  64 , a high stop wall  63  extended along the other side of the linear front sliding groove portion  611 , a second locating block  65  at the rear side of the high stop wall  63  opposite to the first locating block  64 , a retaining hole  6121  in between the second locating block  65  and the rear side of the arched rear sliding groove portion  612  for the positioning of the other end  502  of the tensile spring  50 , a front stop wall  67  in the front side of the linear front sliding groove portion  611 , a hook hole  661  biased from the front side of the linear front sliding groove portion  611  behind the front stop wall  67 , and a stop block  66  provided between the hook hole  661  and the linear front sliding groove portion  611 . The high stop wall  63  has an outwardly curved protruded portion  631  extended along one side of the hook hole  661  The low stop wall  62  has a front notch  621  corresponding to the outwardly curved protruded portion  631  of the high stop wall  63 . 
     The sliding locking block  5  (see FIGS. 7,  10 , and  11 ) comprises a hook rod  51  and a locating rod  52  respectively inserted into the linear front sliding groove portion  611  of the sliding groove  61  of the track  6  to guide movement of the sliding locking block  5  in the sliding groove  61 , a sloping wall  53  and a stop wall  54  disposed at one side opposite to the hook rod  51  and the locating rod  52 , a side locating hole  55  defined between the sloping wall  53  and the stop wall  54 . The push block  4  has a push rod  42 . 
     When the drawer moved backwards with the inner sliding rail  1  (see FIG.  14 ), the push rod  42  of the push block  4  pushes the stop wall  54  of the sliding locking block  5 , thereby causing the sliding locking block  5  to be biased outwards to force the push rod  42  into engagement with the side locating hole  55  and to disengage the locating rod  52  from the stop block  661 . When the locating rod  52  disengaged from the stop block  661 , the tensile spring  50  immediately pulls the sliding locking block  5  and the inner sliding rail  1  backwards (see FIG. 15) to the position where the back sidewall  59  of the sliding locking block  5  is stopped at the front sidewall  640  of the first locating block  64  of the track  6  (see FIG.  16 ). When the back sidewall  59  of the sliding locking block  5  stopped at the front sidewall  640  of the first locating block  64  of the track  6 , the rear end of one lateral sidewall  11  of the inner sliding rail  1  is forced into engagement with the clamping portion  641  of the first locating block  64  of the track  6 . On the contrary, when the drawer pulled to move the inner sliding rail  1  forwards, the push rod  42  of the push block  4  moves the sliding locking block  5  forwards to the position where the locating rod  52  of the sliding locking block  5  reaches the connection area between the linear front sliding groove portion  611  and the stop block  66 . At this time, the push rod  42  of the push block  4  pushes the side locating hole  55  to bias the sliding locking block  5 , thereby causing the locating rod  52  to be forced into engagement with the stop block  66  again, and therefore the drawer and the inner sliding rail  1  are stopped in position. 
     Referring to FIGS. 10 and 11, the sliding locking block  5  has an opening  56  disposed adjacent to the sloping wall  53  and the side locating hole  55 . Due to the presence of the opening  56 , the sloping wall  53  of the sliding locking block  5  can be deformed by the push rod  42  of the push block  4  for enabling the push rod  42  to move into the side locating hole  55  when the sliding locking block  5  forced by an unexpected external force (for example, vibration) and pulled backwards by the tensile spring  50 . 
     The track  6  has a locating open frame  68  in front of the front stop wall  67  for the positioning of a hook  22  of the outer sliding rail  2  (see FIG.  2 ), and two locating holes  642  and  652  respectively formed in the first and second locating blocks  64  and  65  for the positioning of locating rods  23  and  24  of the outer sliding rail  2  respectively. 
     During installation, the two ends  501  and  502  of the tensile spring  50  are respectively fastened to the hook rod  51  of the sliding locking block  5  and the retaining hole  6121  in between the second locating block  65  and the rear side of the arched rear sliding groove portion  612  of the track  6 , keeping the locating rod  52  of the sliding locking block  5  in the linear front sliding groove portion  611 , and then the track  6  is fixedly fastened to the outer sliding rail  2 . 
     As indicated above, the present invention has the following advantages 
       1 . The track  6  provides a sliding groove  61  formed of a linear front sliding groove portion  611  and a arched rear sliding groove portion  612  and a hook hole  661  biased from the front side of the linear front sliding groove portion  611  to match the sliding locking block  5 , which is connected to the track  6  by the tensile spring  50 ; the design of the locating rod  52 , sloping wall  53  and side locating hole  55  of the sliding locking block  5  matches the push rod  42  of the push block  4  to achieve an auto-locking action. Because the track  6  and the sliding locking block  5  have a limited size, they occupy small installation space in the outer sliding rail without affecting the functioning of the sliding track assembly to carry the load. 
       2 . When the inner sliding rail  1  pushed backwards to force the back sidewall  59  of the sliding locking block  5  against the front sidewall  640  of the first locating block  64  of the track  6 , the rear end of one lateral sidewall  11  of the inner sliding rail  1  is automatically forced into engagement with the clamping portion  641  of the first locating block  64  of the track  6 , and therefore the inner sliding rail  1  is positively held in position. 
       3 . Due to the presence of the opening  56  in the sliding locking block  5  adjacent to the sloping wall  53  and the side locating hole  55 , the sloping wall  53  of the sliding locking block  5  can be deformed by the push rod  42  of the push block  4  for enabling the push rod  42  to move into the side locating hole  55  to achieve a locking action when the sliding locking block forced by an unexpected external force and pulled backwards by the tensile spring  50 . 
       4 . Because the track  6  has a locating open frame  68  in front of the in front of the front stop wall  67  for the positioning of the hook  22  of the outer sliding rail  2  and two locating holes  642  and  652  respectively formed in the first and second locating blocks  64  and  65  thereof for the positioning of locating rods  23  and  24  of the outer sliding rail  2  respectively, positive connection between the track  6  and the outer sliding rail  2  is assured. 
     A prototype of auto-locking structure used in a sliding track assembly for drawer has been constructed with the features of FIGS.  2 ˜ 16 . The auto-locking structure used in a sliding track assembly for drawer functions smoothly to provide all of the features discussed 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.