Patent Publication Number: US-7712851-B2

Title: Slide rail assembly

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a slide rail assembly. 
   2. Description of Related Art 
   Slide rails are used in a variety of applications, including business furniture, kitchen drawers, electronic racks, and copiers. One type of slide rail is a telescopic slide rail. Telescopic slide rails often include two, three, four or more telescoping members. The shape of a slide rail, and the individual members, are determined by the design. The slides can be frictional, with lubricated members rubbing against each other, or a slide assembly may include roller or ball bearings for easier movement. The members in such assemblies tend to be C-shaped in nature. 
   A conventional three-section slide rail assembly for a drawer includes a first slide rail (e.g. outer slide rail), a second slide rail (e.g. middle slide rail), and a third slide rail (e.g. inner slide rail). A ball bracket is sandwiched between any two of the first slide rail, the second slide rail, and the third slide rail to provide a smooth sliding movement. In such basic slide mechanisms; the order in which the second slide rail extends relative to the first slide rail and the third slide rail extends relative to the second slide rail is unpredictable. Considerations of strength and smoothness of operation may render a given order or sequence preferable in a given slide configuration. Further, activation of external mechanisms such as cabinet interlocks may require a specific sequence of operation. 
   Consequently, it is required to provide a slide rail assembly having a latch mechanism urging collapsing of slide rails in a specific desired order. 
   SUMMARY OF THE INVENTION 
   In one preferred embodiment, a slide rail assembly includes a first slide rail having a release portion, a second slide rail having a slot, a third slide rail having a stop portion, a latch member slidably attached to a slot of the second slide rail, and a resilient member connected to the latch member for returning the latch member to an original position. The latch member includes a first engaging portion and a second engaging portion located at opposite sides of the second slide rail. Wherein the first engaging portion engages with the stop portion of the third slide rail such that the third slide rail is capable of driving the second slide rail to slide together relative to the first slide rail. The release portion of the first slide rail is capable of engaging with the second engaging portion to bias the latch member to slide along the slot to release the third slide rail from the first engaging portion. 
   Other advantages and novel features of the present invention will become more apparent from the following detailed description of preferred embodiment when taken in conjunction with the accompanying drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded, isometric view of the slide rail assembly according to a preferred embodiment of the present invention; 
       FIG. 2  is an inverted view of  FIG. 1 ; 
       FIG. 3  is an partially assembled view of  FIG. 1 ; 
       FIG. 4  is an assembled view of  FIG. 1 ; and 
       FIGS. 5 and 6  are lateral views of  FIG. 4  showing the slide rail assembly in two states. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 1 and 2 , in an embodiment of the invention, a slide rail assembly includes a first slide rail  10 , a second slide rail  20 , a third slide rail  30 , a latch member  40 , and a resilient member  50 . 
   The first slide rail  10  includes a bottom wall and two sidewalls extend from opposite sides of the bottom wall. A release portion  12  extends inward from the bottom wall of the first slide rail  10  at a predetermined releasing position. The release portion  12  includes an inclined surface  122  formed at a free side thereof. 
   The second slide rail  20  includes a bottom wall and two sidewalls extending from opposite sides of the bottom wall respectively. The second slide rail  20  includes an arc-shaped slot  22  defined in the bottom wall at a predetermined retaining position, a protrusion  24  formed on the bottom wall thereof, and an aperture  26  defined in the bottom wall between the slot  22  and the protrusion  24 . The slot  22  has a larger end and a smaller end. 
   The third slide rail  30  includes a bottom wall and two sidewalls extending from opposite sides of the bottom wall respectively. A stop portion  32  is formed on the bottom wall of the third slide rail  30  in the vicinity of one end of the third slide rail  30 . The stop portion  32  has a stop surface  324  formed thereon adjacent to the one end of the third slide rail  30 . 
   The latch member  40  is generally column-shaped. A neck portion  42  is defined in a middle portion of the latch member  40 . A first engaging portion  44  and a second engaging portion  46  are formed on opposite ends of the latch member  40  respectively. 
   The resilient member  50  is generally R-shaped, and preferably made by bending a resilient steel wire. The resilient member  50  includes a mounting portion  52  at a middle thereof, and a pressing portion  54  and a locking portion  56  at opposite ends thereof respectively. 
   Referring also to  FIGS. 3 and 4 , in assembly, the latch member  40  is inserted into the slot  22  of the second slide rail  20  via the larger end and biased to the smaller end. Two sidewalls bounding the slot  22  engage in the neck portion  42  of the latch member  40 . The mounting portion  52  of the resilient member  50  is fixed around the protrusion  24  of the second slide rail  20 . The locking portion  56  of the resilient member  50  is locked in the aperture  26  of the second slide rail  20 . The pressing portion  54  of the resilient member  50  presses on the neck portion  42  of the latch member  40 . The first to third slide rails  10 ,  20 ,  30  are nested in sequence to form the slide rail assembly. 
   Referring also to  FIG. 5 , in collapsing the slide rail assembly from an extended state, the third slide rail  30  is pushed to slide into the second slide rail  20 . When the stop portion  32  of the third slide rail  30  arrives at the latch member  40 , the stop surface  324  of the stop portion  32  engages with the first engaging portion  44  of the latch member  40  to drive the second slide rail  20  simultaneously to collapse into the first slide rail  10 . 
   Referring also to  FIG. 6 , when the latch member  40  arrives at the release portion  12  of the first slide rail  10 , the inclined surface  122  of the release portion  12  presses the second engaging portion  46  of the latch member  40  to drive the latch member  40  to slide toward the larger end of the slot  22  of the second slide rail  20  along the slot  22  against resistance of the resilient member  50  until the first engaging portion  46  of the latch member  40  disengages from the stop surface  122  of the stop portion  12 , and the third slide rail  30  continues to slide into the second slide rail  20 . The resilient member  50  restores the latch member  40  toward the smaller end of the slot  22  of the second slide rail  20 . 
   It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.