Patent Publication Number: US-7722140-B2

Title: Slide rail

Description:
BACKGROUND 
   1. Field of the Invention 
   The present invention generally relates to slide rails. Particularly, the present invention relates to slide rails without ball bearings. 
   2. Description of Related Art 
   Slide rails are used for guiding objects, such as drawers, to be pushed into or pulled out from bodies, such as furniture. There are many kinds of slide rails, some have ball bearings and others do not. Slide rails having ball bearings are easy to be pulled or pushed, for they have little friction. However, the ball bearings add to the cost of the slide rails, and brackets for supporting the ball bearings tend to be broken, which causes the slide rail to become unusable. 
   Slide rails without ball bearings have lower costs than those having ball bearings. Such slide rails each has at least two slides movable relative to each other. The two slides contact each other in a line-contact mode. This kind of contact makes the slide rails unable to support heavy loads. 
   Therefore, a need exists in the industry to provide a low-cost slide rail which can support heavy loads. 
   SUMMARY 
   In one embodiment, a slide rail includes a first slide and a second slide. The first slide provides a first arced surface. The second slide provides a second arced surface for being engaged with the first arced surface, so that the second slide is slidable relative to the first slide. The second arced surface has a same curvature as that of the first arced surface. 
   Other advantages and novel features of the slide rail will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a slide rail in accordance with an exemplary embodiment of the present invention; 
       FIG. 2  is an assembled view of the slide rail of  FIG. 1 ; and 
       FIG. 3  is a cross-sectional view of the slide rail of  FIG. 2 . 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1  and  FIG. 2 , a slide rail in accordance with an exemplary embodiment includes a first slide  20 , a second slide  40 , and a third slide  60 . The first slide  20  is used for being fixed on a stable object, like a kind of furniture, or racks for servers. The third slide  60  can be fixed on a movable object, such as drawers of the furniture, or servers to be installed in the racks. The second slide  40  is received in the first slide  20 , and installed between the first slide  20  and the third slide  60 . The second slide  40  is movable relative to the first slide  20  and the third slide  60 . Through the motion between the three slides, the movable object can be pushed into or pulled out from the stable object. 
   Referring to  FIG. 3 , the first slide  20  includes a bottom wall  22  and a pair of sidewalls  24 ,  26 . The bottom wall  22  extends in the longitudinal direction, along with the sidewalls  24  and  26 . The two sidewalls  24  and  26  are extended from the bottom wall  22  at its two longitudinal sides, in an identical direction. Ends  242  and  262  of the two sidewalls  24  and  26  are respectively turned over to be generally parallel with the bottom wall  22 . At an inner side of each of the sidewalls  24  and  26 , first recesses  244 ,  264  are provided respectively. 
   The second slide  40  includes a main plate  42  and two side parts  44 ,  46 . The two side parts  44  and  46  are symmetrically disposed on two sides of the main plate  42 , integrally extending from the main plate  42 . 
   The main plate  42  includes a pair of end portions  422 , a flat panel  424 , and a pair of connection portions  426 . The end portions  422  are disposed on two side of the flat panel  424 , and are parallel with the flat panel  424 , which is parallel with the bottom wall  22  of the first slide  20  after assembled. The connection portions  426  connect the pair of end portions  422  and the flat panel  424  at two sides of the flat panel  424 , respectively. The connection portions  426  are symmetrically inclined to the flat panel  424 . After assembly, the end portions  422  are nearer the bottom wall  22  than the flat panel  424 . 
   The side parts  44  and  46  have generally the same structure, so the side part  46  is mainly described in below description for simplicity. The side part  46  includes a first curve  462 , a second curve  464 , and a connection portion  466 . The first curve  462  is extended from the end portion  422  of the main plate  42 . The first curve  462  interconnects the end portion  422  and the connection portion  466 , which is parallel with the end portion  422 . A first camber  468  is provided on an outer surface of the first curve  462 . The curvature of the first camber  468  is the same as the curvature of the first recess  264  of the first slide  20 . The connection portion  466  is generally extended from the first curve  462  in a direction approaching the inclined connection portion  426  of the main plate  42 . The second curve  464  extends from the connection portion  466  in a direction away from the connection portion  426  of the main plate  42 . Accordingly, a second recess  470  is provided in an inner surface of the second curve  464 . 
   Similarly, the side part  44  includes a first curve  442 , a second curve  444 , and a connection portion  446 . The connection portion  446  interconnects the first curve  442  and the second curve  444 . The first curve  442  provides a first camber  448  on the outer surface thereof, and the second curve  444  provides a second recess  450  on the inner surface thereof. Thus the connection portions  446 ,  466  of the side parts  44 ,  46  extend toward each other, and the extension ends of the second curves  444 ,  464  extend away from each other. 
   The third slide  60  includes an installation plate  62  and two arms  64 ,  66  symmetrically disposed on two sides of the installation plate  62  respectively. The installation plate  62  can be fixed to the movable object when in use, and is parallel with the bottom wall  22  of the first slide  20  after assembly. The arms  64  and  66  that have symmetrically the same structures are used for clamping the second slide  40  when assembled. 
   The arm  64  includes a bending portion  642 , a clamp plate  644 , and a free end  646 . The bending portion  642  interconnects the installation plate  62  and the clamp plate  644 . The bending portion  642  is set in such a manner that, the extension end of the clamp plate  644  other than its opposite end that is connected to the bending portion  642 , points at the second curve  444 , and is received in the second recess  450  of the second curve  444 . The bending portion  642  guides the installation plate  62  to turn over from its edge to its central part. 
   The extension end of the clamp plate  644 , other than its opposite end that is connected to the bending portion  642 , is turned over to form the free end  646 . The free end  646  is generally parallel with the clamp plate  644 . At a cross that the clamp plate  644  meets the free end  646 , a second camber  648  is provided. The second camber  648  has a same curvature as that of the second recess  450 . 
   Similarly, the arm  66  includes a bending portion  662 , a clamp plate  664 , and a free end  666 . A second camber  668  is also provided at the cross of the clamp plate  664  meets the free end  666 . Thus, the clamp plates  644 ,  664  extend toward each other. 
   In assembly, the second slide  40  is received in the first slide  20 , with the first cambers  448 ,  468  slidably engaging with the first recesses  244 ,  264 , respectively. Thus, the second slide  40  and the first slide  20  contact each other at arced surfaces thereof. The third slide  60  is slidably sleeved over the second curves  444 ,  464  of the second slide  40 , with the second cambers  648 ,  668  engaging with the second recesses  450 ,  470 , respectively. Accordingly, the second slide  40  and the third slide  60  contact each other at arced surfaces thereof in other than in line-contact mode. 
   Some lubricant can be added on the contact surfaces of the slides, which can result in smooth movement during pushing and pulling of the slides, and facilitates use of the slide rail. 
   The slides of the slide rail contact each other at arced surfaces, which reduces the intensity of pressure applied on the slides. Accordingly, the slide rail is able to endure heavy loads. The arced contact surfaces can also be utilized in slide rails having only two slides, or four or more slides, as well. 
   The embodiments were chosen and described in order to explain the principles of the invention and their practical application so as to enable others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.