Patent Publication Number: US-7588299-B2

Title: Rail assembly for drawers

Description:
FIELD OF THE INVENTION 
   The present invention relates to a rail assembly for drawers and includes an retrieving unit which allows the second and/or third rail to be moved to longer distance. 
   BACKGROUND OF THE INVENTION 
   A conventional rail assembly is widely used on drawers and generally includes a first rail which is fixed to the desk and the second and third rails are connected to the side of the drawer. The second and third rails are retractably connected to each other and both of which are movable in the first rail so that the drawer can be pulled out a desired distance and pushed back completely. 
   A retrieving unit is used at the end of the first rail which is operatively connected to the second rail so that when the drawer is to be pushed back, the springs of the retrieving unit automatically pulls the drawer inward into the space for the drawer. However, the conventional retrieving unit occupies a certain space and length so that the travel distance of the second and third rails is reduced. In other words, the conventional rail assembly requires longer second and third rails to allow the drawer to be pulled outward to its desired distance which usually three times of the length of the first rail. 
   As shown in  FIG. 9  which shows a conventional rail assembly and includes a first rail (the outer rail not numbered) and a retrieving unit is fixed in an end of the first rail, the retrieving unit includes an extension portion  91 . A second rail  90  and a third rail  93  are retractably received in the first rail. The second rail  90  includes a recess  92  defined in an end thereof so that when the second rail  90  is moved toward the retrieving unit, the extension portion  91  is received in the recess  92  and does not interfere the second rail  90 . The second rail  90  is then weakened and cannot move to its extreme position because of the springs on two side of the extension portion  91  interfere the second rail  90 . The extension portion  91  actually interferes the movement of the third rail  93 . 
   The present invention intends to provide a rail assembly for drawer and the retrieving unit does not interfere the movement of the second and third rails so that both of the second and third rails can be completely retracted in the first rail and can be pulled outward fully. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a rail assembly for drawers and the assembly comprises a substantially U-shaped first rail having two sidewalls and a first space is defined between the two sidewalls. A substantially U-shaped second rail is movably received in the first space and includes two sidewalls with a second space defined between the two sidewalls of the second rail. An escape space is defined inward from an underside of the second rail. A substantially inverted U-shaped third rail is movably received in the second space. A retrieving unit includes a fixed member which is fixedly located in an end of the first rail and received in the first space. An extension rail extends from the fixed member and located in the first space. A movable member is slidably connected to the extension rail. The extension rail is sized to be received in the escape space of the second rail so that the second rail can be moved toward the fixed member without interference. The movable member includes two upright sides and the two sidewalls of the third rail are guided by two respective insides of the two upright sides. Two grooves are defined in a top on two sides of the fixed member and the two sidewalls of the third rail are slidably engaged with the grooves. 
   The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view to show the rail assembly of the present invention; 
       FIG. 1-1  shows an underside of the connection member; 
       FIG. 2  is a perspective view to show the rail assembly of the present invention; 
       FIG. 3  is a top view to show that the second and third rails are received in the first rail of the rail assembly of the present invention; 
       FIG. 4  is a top view to show that the second and third rails are pulled away from the movable member in first rail of the rail assembly of the present invention; 
       FIG. 5  is a side cross sectional view to show the status disclosed in  FIG. 4 ; 
       FIG. 6  is a side cross sectional view to show the status disclosed in  FIG. 5 ; 
       FIG. 7  is an exploded view to show another embodiment of the rail assembly of the present invention; 
       FIG. 8  is a perspective view to show the rail assembly of the present invention shown in  FIG. 7 , and 
       FIG. 9  shows a conventional rail assembly. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1 and 2 , the rail assembly  1  for drawers of the present invention comprises a substantially U-shaped first rail  10  having two sidewalls and a first space  11  is defined between the two sidewalls. A plurality of rollers units  12  are connected to two insides of the two sidewalls of the first rail  10 . A substantially U-shaped second rail  20  is movably received in the first space  11  and includes two sidewalls with a second space  21  defined between the two sidewalls of the second rail  20 . An escape space  23  is defined inward from an underside of the second rail  20 . A plurality of rollers units  22  are connected to two insides of the two sidewalls of the second rail  20 . A substantially inverted U-shaped third rail  30  is movably received in the second space  21  and includes a third space  31  defined between two sidewalls of the third rail  30 . 
   A retrieving unit  40  includes a fixed member  41  which is fixedly located in an end of the first rail and received in the first space  11 . An end plate is connected to the fixed member  41  so as to seal the first space  11 . An extension rail  412  extends from the fixed member  41  and located in the first space  11 . A movable member  42  is slidably connected to the extension rail  412  and can be stopped by a stop rod  415  extending from the fixed member  41 . A positioning slot  413  is connected to a distal end of the extension rail  412  and the movable member  42  is removably positioned on the positioning slot  413  by a connection member  421  which will be described later. Two springs  414  are located on the two sides of the fixed member  41  and connected to the movable member  42 . It is noted that the extension rail  412  and the movable member  42  are sized to be received in the escape space  23  of the second rail  20 , so that the second rail  20  can be moved to a position above the extension rail  412  without interference. 
   The movable member  42  includes two upright sides  422  and the two sidewalls of the third rail  30  are guided by two respective insides of the two upright sides  422  when the third rail  30  passes the movable member  42 . Two grooves  416  are defined in a top on two sides of the fixed member  41  and the two sidewalls of the third rail  30  slidably engaged with the grooves  416  so that the third rail  30  can be received in the first space  11  of the first rail  10  completely. 
   The connection member  421  is located on a top of the movable member  42  and the connection member  421  includes a first protrusion  4211  and a second protrusion  4212  extending from an underside of two ends thereof. The first and second protrusions  4211 ,  4212  extend through two respective slots in the movable member  42  and the connection member  421  includes a curved end surface facing the third rail  30 . 
   As shown in  FIGS. 4 and 6 , when the drawer (not shown) is pulled to its open position, the second rail  20  is slid away from the retrieving unit  40  and the third rail  30  is slid relative to the second rail  20 . The protrusion of the third rail  30  pulls the movable member  42  unit the protrusion of the third rail  30  is disengaged from the side notch of the connection member  421 . 
   As shown in  FIGS. 3 and 5 , when the drawer is pushed to its closed position, the second rail  20  is moved toward the retrieving unit  40  and the extension rail  412  is received in the escape space  23 , so that the second rail  20  can be moved to an end of the fixed member  41 . The two sidewalls of the third rail  30  are guided by the two upright sides  422  of the movable member  42  and slidably engaged with the grooves  416 . The third rail  30  includes a protrusion (not shown) extends from its bottom and is able to move along the curved end surface to be slightly engaged with one of the two notches in one side of the connection member  421  to pivot the connection member  421 . By the connection member  421 , the third rail  30  can be moved with the movable member  42  when the drawer (not shown) is pushed to its closed position. 
   Therefore, the third rail  30  can be moved to the very end of the fixed member  41 . The springs  414  help the user to pull the movable member  42  so that the drawer automatically moves to its closed position. 
     FIGS. 7 and 8  show another embodiment of the present invention, wherein the second rail  20  in the first embodiment is omitted and only the third rail  30  is slidably engaged within the first space  11 . The third space  31  is sized such that the extension rail  412  is received therein so that the two sidewalls of the third rail  30  can be moved within the grooves  416  in the fixed member  41 . 
   While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.