Patent Publication Number: US-6220683-B1

Title: Sliding track assembley for drawer

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to a sliding track assembly for drawer, and more particularly to a durable sliding track assembly, which produces less friction resistance during loading of the inner rail, and enables the inner rail to be quickly and easily loaded or unloaded. 
     U.S. Pat. No. 5,577,821 discloses a sliding track assembly for drawer. This structure of sliding track assembly is functional, however it still has drawbacks. As illustrates in FIGS. 1 and 2, the stop member comprises two retaining portions respectively backwardly protruded from two upright side blocks thereof for engagement with two side walls of the second sliding bearing to hold down the second sliding bearing in the intermediate rail when disconnecting the inner rail with the drawer from the intermediate rail, preventing the second sliding bearing from bearing pushed backwards or damaged when inserting the inner rail into the second sliding bearing in the intermediate rail to reload the drawer. The drawback of this design is that the retaining portions of the stop member wear quickly with use, and tend to be permanently deformed. When the retaining portions of the stop member start to wear, or are permanently deformed, the stop member can not positively hold down the second sliding bearing when disconnecting the inner rail with the drawer from the intermediate rail. 
     FIGS. 3 and 4 show a sliding track assembly according to U.S. Pat. No. 5,722,750. According to this design, the stop member comprises two backwardly extended rear locating plates adapted for holding down the second sliding bearing. The locating plates each have a beveled rear guide edge adapted to guide the second sliding bearing into engagement with the locating plates, and a notch extended through the respective two opposite side walls. The notch separates the rear end of the respective locating plate into an upper part and a lower part, and enables the upper part of the rear end of the respective locating plate to be forced downwards when the front positioning portions of the bottom wall of the second sliding bearing are moved into engagement with the locating plates. This design is still not satisfactory in function. The front positioning portions of the bottom wall of the second sliding bearing may be erroneously engageed into the notches the locating plates due to improper application of force, affecting normal functioning of the sliding track assembly. 
     The present invention has been accomplished to provide a sliding track assembly for drawer, which eliminates the aforesaid problems. In one embodiment of the present invention, the sliding track assebmly comprises an outer rail fixedly mounted inside a desk, an intermediate rail carried on a first sliding bearing and moved in and out of the outer rail, an inner rail carried on a second sliding bearing and moved with a drawer in and out of the intermediate rail, and a stop member installed in the intermediate rail to limit forward movement of the inner rail relative to the intermediate rail, wherein the stop member has two rear retaining frames for holding down the second sliding bearing when disconnecting the inner rail from the intermediate rail, the rear retaining frames each having an upright retaining wall for engagement with opposite side walls of the second sliding bearing, the upright retaining wall of each rear retaining frame recessed portion on the respective side wall of the second sliding bearing, the upright retaining walls of the rear retaining frames being respectively spaced from the upright side walls of the intermediate rail by a gap, which enables the upright retaining walls of the rear retaining frames of the stop member to be respectively forced outwards to minimize friction during loading of the inner rail with the drawer on the intermediate rail. In another embodiment of the present invention, the sliding track assembly sliding track assembly comprises on outer rail, an inner rail, a sliding bearing coupled between the outer rail and the inner rail, and a stop member installed in the outer rail, the stop member comprising two upright side blocks, which stop the sliding bearing from being moved out of the outer rail, two rear retaining frames adapter to hold down the sliding bearing when dosconnecting the inner rail with the second device from the outer rail, preventing the sliding bearing from being pushed backwards or damaged when inserting the inner rail into the sliding bearing in the outer rail to reload the drawer, the rear retaining frames of the stop member each comprising an upright retaining wall respectively backwardly extended from the upright side blocks of the stop member and adapted for engagement with two opposite side walls of the sliding bearing, a bottom retaining wall adapted for engagement with the front positioning portions of the bottom wall of the sliding bearing, and a longitudinal split disposed between the upright retaining wall and the bottom retainig wall for enabling the bottom retaining wall to be forced outwards to minimize friction resistance during loading of the inner rail with the drawer on the outer rail, the bottom retaining wall of each rear retaining frame of the stop member comprising a raised portion adapted for engagement with a recessed portion on the front positioning portions of the bottom wall of the sliding bearing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sliding track assembly installed in a drawer inside a cabinet according to U.S. Pat. No. 5,577,821. 
     FIG. 2 is an exploded view of the sliding track assembly according to U.S. Pat. No. 5,577,821. 
     FIG. 3 illustrates a stop member used in a sliding track assembly according to U.S. Pat. No. 5,722,750. 
     FIG. 4 is an exploded view of a sliding track assembly, according to U.S. Pat. No. 5,722,750. 
     FIG. 5 illustrates a stop member for use in a sliding track assembly according to a first embodiment of the present invention. 
     FIG. 6 is a stop plain view of the stop member shown in FIG.  5 . 
     FIG. 7 is a cross sectional view of the stop member shown in FIG.  5 . 
     FIG. 8 is an exploded view of a sliding track assembly according to the first embodiment of the preset invention. 
     FIG. 9 is an assembly view of the sliding track assembly shown in FIG. 8 before the installation of the inner rail in the second sliding bearing in the intermediate rail. 
     FIG. 10 is a cross sectional view in an enlarge scale of a part of FIG. 9, showing engagement between the stop member and the second sliding bearing. 
     FIG. 11 is an elevational view of a stop member for a sliding track assembly according to a second embodiment of the present invention. 
     FIG. 12 is another elevational view of the stop member shown in FIG. 11 when viewed from another angle. 
     FIG. 13 is a sectional view of a part of the stop member shown in FIG.  11 . 
     FIG. 14 is a transverse view in section of the stop member shown in FIG.  11 . 
     FIG. 15 is an assembly view of the sliding track assembly according to the second embodiment of the present invention before installation of the inner rail in the sliding bearing in the outer rail. 
     FIG. 16 is a sectional view in an enlarged scale of a part of FIG. 15, showing engagement between the stop member and the sliding bearing. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to Figures from  5  through  10  , a sliding track assembly in accordance with the present invention comprises a locating plate  4 , a stop member  5 , an outer rail  6 , an intermediate rail  7 , an inner rail  8 , a first sliding bearing  91  coupled between the outer rail  6  and the intermediate rail  7 , and a second sliding bearing  92  coupled between the intermediate rail  7  and the inner rail  8 . The outer rail  6  is fixedly fastened to the inside wall of, for example, a desk (not shown). The inner rail  8  is fixedly fastened to one lateral side wall of a drawer (not shown). The locating plate  4  is injection-molded from plastics, and fixedly fastened to the inner rail  8  near the rear end of the inner rail  8 . The intermediate rail  7  is coupled between the outer rail  6  and the inner rail  8 , and moved in and outer of the outer rail  6 . 
     The stop member  5  is installed in the front end of the intermediate rail  7 , comprising a protruding block  51  for engagement with the locating plate  4  to limit forward movement of the inner rail  8  in the intermediate rail  7 , two upright side blocks  53  and  54 , which stop the second sliding bearing  92  from being moved out of the front end of the intermediate rail  7 , two rear retaining frames  55  and  56  bilaterally disposed at the rear side thereof and adapted to hold down the second sliding bearing  92  when disconnecting the inner rail  8  with the drawer from the intermediate rail  7 , preventing the second sliding bearing  92  from being pushed backwards or damaged when inserting the rear end  81  of the inner rail  8  into the second sliding bearing  92  in the intermediate rail  7  to reload the drawer. The rear retaining frames  55  and  56  have a respective sloping guide edge  551  or  561  adapted to act with respective front positioning portions  923  and  924  of the bottom wall of the second sliding bearing  92 , for enabling the second sliding bearing  92  to be moved into engagement with the rear retaining frames  55  and  56  when disconnecting the inner rail  8  with the drawer from the intermediate rail  7 . 
     The main characteristics of the present invention is outlined hereinafter with reference to Figures from  5  through  10  again. The retaining frames  55  and  56  each comprise an upright retaining wall  552  or  562  extended from the rear end  541  or  531  of the upright side block  54  or  53  adapted for engagement with two opposite side walls  925  and  926  of the second sliding bearing  92 . The upright retaining wall  552  or  562  of the retaining frame  55  or  56  has a raised portion  5521  or  5621  adapted for engagement with a recessed portion  9251  or  9261  on the side wall  925  or  926  of the second sliding bearing  92 . The upright retaining walls  552  and  562  of the rear retaining frames  55  and  56  of the stop member  5  have a certain thickness, and are respectively spaced from two upright side walls  71  of the intermediate rail  7  by a gap (see FIG.  10 ). The gap enables the upright retaining walls  552  and  562  of the rear retaining frames  55  and  56  of the stop member  5  to be respectively forced outwards to minimize friction resistance during loading of the inner rail  8  with the drawer on the intermediate rail  7 . The upright retaining walls  552  and  562  of the rear retaining frames  55  and  56  of the stop member  5  each have a beveled guide edge  5523  or  5623  (see FIGS. 5 and 6) adapted for guiding the side walls  925  and  926  of the second sliding bearing  92  in and out of the rear retaining frames  55  and  56  of the stop member  5 . 
     Figures from  11  through  16  show an alternate form of the present invention. This alternate form eliminates the aforesaid intermediate rail  7  and first sliding bearing  91 ′, and the stop member  5  is directly installed in the front end of the outer rail  6 , that is, the sliding track assembly of this alternate form is comprised of an outer rail  6  fixedly mounted inside the desk, an inner rail  8  fixedly fastened to the drawer, a locating plate  4  fixedly fastened to the inner rail  8  near the rear end  81  of the inner rail  8 , a sliding bearing  92 ′ coupled between the outer rail  6  and the inner rail  8 , and a stop member  5 ′ fixedly mounted in the front end of the outer rail  6 . The stop member  5 ′ comprises a protruding block  51 ′ for engagement with the locating block  4  to limit forward movement of the inner rail  8  in the outer rail  6 , two upright side blocks  53 ′ and  54 ′, which stop the sliding bearing  92 ′ from being moved out of the front end of the oute rail  6 , two rear retaining frames  55 ′ and  56 ′ (see FIGS. 11 and 12) adapted to hold down the sliding bearing  92 ′ when disconnecting the inner rail  8  with the drawer from the outer rail  8 , preventing the sliding bearing  92 ′ from being pushed backwards or damaged when inserting the rear end  81  of the inner rail  8  into the sliding bearing  92 ′ in the outer rail  6  to reload the drawer. The rear retaining frames  55 ′ and  56 ′ have a respective sloping guide edge  551 ′ or  561 ′ adapted to act with respective front positiong portions  923 ′ and  924 ′ of the bottom wall of the sliding bearing  92 ′, for enabling the sliding bearing  92 ′ to be moved into engagement with the rear retaining frames  55 ′ and  56 ′ when disconnecting the inner rail  8  with the drawer from the outer rail  6 . 
     Referring to FIGS. 11 through 16 again, the rear retaining frames  55 ′ and  56 ′ each comprise an upright retaining wall  552 ′ or  562 ′ extended from the rear end  541 ′ or  531 ′ of the upright side block  54 ′ or  53 ′ and adapted for engagement with two opposite side walls of the sliding bearing  92 ′, a bottom retaining wall  550 ′ or  560 ′ adapted for engagement with the front positioning portions  923 ′ and  924 ′ of the bottom wall of the sliding bearing  92 ′. The bottom retaining wall  550 ′ or  560 ′ of the retaining frame  55 ′ or  56 ′ has a raised portion  5501 ′ or  5601 ′ adapted for engagement with a recessed portion  9231 ′ or  9241 ′ on the front positioning portions  923 ′ and  924 ′ of the bottom wall of the sliding bearing  92 ′. The upright retaining walls  552 ′ and  562 ′ of the rear retaining frames  55 ′ and  56 ′ have a substantially crescent-like cross section. The rear retaining frames  55 ′ and  56 ′ each further comprise a longitudinal split  5502 ′ or  5602 ′ disposed between the upright retaining wall  552 ′ or  562 ′ and the bottom retaining wall  550 ′ or  560 ′ for enabling the bottom retaining wall  550 ′ or  560 ′ of the retaining frame  55 ′ or  56 ′ to be respectively forced outwards to minimize friction resistance during loading of the inner rail  8  with the drawer on the outer rail  6 .