Abstract:
A drawer slide assembly has at least three telescoping slide channels, including an outer channel, an intermediate channel and an inner channel. A mechanism is provided to control the sequential movement of the channels between the open and closed positions including a retention lock between the two inner most channels which is released upon sliding movement of those channels together toward the open position and engagement of a lever mounted on the intermediate channel with a raceway of the outer channel to thereby release the inner channel.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This is a utility application based upon previously filed provisional application Serial No. 60/240,670 filed Oct. 16, 2000 for a Drawer Slide With Sequence Control Mechanism which is incorporated herewith by reference and for which priority is claimed.  
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    In a principal aspect, the present invention relates to the improvement in a three-part drawer slide of a mechanism for controlling the sequence of operation of the separate slide members or channels comprising the slide.  
           [0003]    Drawers mounted on slides in filing cabinets often are comprised of multiple, telescoping slide channels. Typically, three or more sliding channels are utilized on each side of a drawer. One of the channels is connected to the wall of the drawer cabinet. A second or intermediate channel slides within the first channel. A third channel is connected to the side of the drawer. Withdrawal of the drawer from the cabinet to open the drawer effects telescoped extension of the second and third channels.  
           [0004]    It is often desirable to provide that the channels will move sequentially. That is, typically, the second or intermediate and third channel will move in unison. Thus, if a drawer is partially opened, the second or intermediate channel and third or drawer channel connected to the drawer will first extend or telescope together as a unit filly from the channel connected to the cabinet wall. Thereafter, upon further opening of the drawer, the outer channel or third channel will extend from the second or intermediate channel.  
           [0005]    Providing a mechanism to ensure sequential operation of the second and third drawer slide channels is thus a desirable objective.  
         SUMMARY OF THE INVENTION  
         [0006]    Briefly, the present invention comprises an improvement in drawer slides having three or more channels. The improvement relates to the mechanism for controlling the sequential operation of the drawer slide channels or elements. In particular, in a construction having a first channel, an intermediate or second channel slidable in the first channel and a third channel slidable in the second or intermediate channel, there is provided a retention mechanism interconnecting the second and third channels. The retention mechanism ensures that the second and third channels move simultaneously as a unit when the assembly of second and third channels is moved from the fully closed toward the open position. Upon reaching the full extension or sliding movement of the second and third channels as a unit in the first or outside channel, a release mechanism disengages the retention mechanism connecting the second and third channels. In a preferred embodiment, the release mechanism comprises a slot or raceway mounted on the first channel that engages a retention pin associated with the second and third channels and releases that retention mechanism. Upon release, the third channel may be telescoped or extended from the second channel thereby permitting the full opening of the drawer.  
           [0007]    Thus, it is an object of the invention to provide an improved channel slide construction for drawers having three or more telescoping channels.  
           [0008]    It is a further object of the invention to provide a channel slide construction for drawers having three or more channels wherein two of the channels are retained in an interlocked relationship until they telescope in unison in a third channel beyond a fixed distance.  
           [0009]    It is a further object of the invention to provide a mechanism for sequential operation of multiple channel members which is economical, rugged, easy to assemble and relatively safe.  
           [0010]    These and other objects, advantages and features of the invention will be set forth in the detailed description which follows.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0011]    In the detailed description which follows, reference will be made to the drawing comprised of the following figures:  
         [0012]    [0012]FIG. 1 is an isometric view of a typical drawer and cabinet construction incorporating drawer slides of the type comprising the invention;  
         [0013]    [0013]FIG. 2 is an enlarged isometric view of a drawer slide incorporating a sequential control mechanism of the invention;  
         [0014]    [0014]FIG. 3 is an enlarged isometric view of the control mechanism of FIG. 2;  
         [0015]    [0015]FIG. 4 is a side plan view or elevation of the slide construction depicting the three channels comprising an outer, an intermediate channel and an inner channel wherein the intermediate channel and inner channel are connected so as to move together in unison as a drawer attached to the inner channel is opened by movement in the direction of the arrow;  
         [0016]    [0016]FIG. 4A is a cross sectional view illustrating a resilient lever arm mounted on the intermediate channel and engaged by the inside channel taken along the line  4 A- 4 A in FIG. 4;  
         [0017]    [0017]FIG. 5 is an elevation similar to FIG. 4 wherein the inner channel has been moved to a position wherein engagement between the inner channel and the intermediate channel is effected by release of a connecting lever arm; and  
         [0018]    [0018]FIG. 6 is an elevation similar to FIG. 4 depicting the operation of the slide as a result of movement of the inner channel toward the closed position after the intermediate channel and inner channel have been disconnected, the drawer fully opened and then subsequently moved to the closed position; and  
         [0019]    [0019]FIG. 7 is an elevation of the three channels wherein they are in the closed position and the inner channel is faced with a resilient retaining lug. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]    Referring to the figures, the slide construction of the invention is designed for incorporation in a file cabinet for mounting of drawers in the cabinet. The slide construction typically includes three or more slide channels which telescopically fit one into the other.  
         [0021]    Referring to FIG. 1, cabinet  10  includes drawers  12  slidably mounted for horizontal movement into and out of the cabinet  10 . The drawers  12  are mounted on multiple channel slides, such as a drawer slide  14 , comprised of a first or outside channel  16 , a second or intermediate channel  18  that is telescopically and slidably mounted in the first channel races, such as bearing races. A third or inner or inside channel  20  is attached to drawer  12  and is telescopically and slidably mounted in the intermediate channel  18  by raceways and bearings. Note that the outside channel  16  is generally U-shaped with a flat side or top side of the U facing against the inner wall of cabinet  10 . The intermediate channel  18  is similarly U-shaped and fits within the outside channel  16  being slidably mounted therein on raceways. The third or inside drawer channel  20  is also U-shaped; however, it is inserted or placed within the intermediate channel so that the flat surface or crown of the U-shape is facing inwardly from the cabinet  10  and against the side wall of drawer  12 . FIG. 3 and FIG. 2 illustrate the arrangement of the described channels  16 ,  18 , and  20 . Thus, channel  16  is attached to the inside wall of cabinet  10 . Channel  18  slides on raceways or bearing races  17  intermediate outside channel  16  and intermediate channel  18 . Inside channel  20  likewise slides on bearing races or raceways  22  mounted in intermediate channel  18 . The inside channel  20  includes tabs, for example, tab  24 , for attachment to the side wall of a drawer such as drawer  12 .  
         [0022]    The subject matter of the invention relates to a mechanism for interlocking or maintaining the third or inside drawer channel  20  and the second or intermediate channel  18  locked or engaged one with the other when a drawer  12  is initially opened. In that manner, the inside channel  20  and intermediate channel  18  will initially move in unison together toward the open position as the drawer  12  is opened. Upon reaching the desired limit of extension of the two channels; namely, inside channel  20  and intermediate channel  18  toward the open position, a mechanism is provided which releases the engagement of the inside channel  20  from the intermediate channel  18  thereby permitting extension of inside channel  20  as the drawer is moved to a fully opened position. As a further feature of the invention in combination, the inside channel  20  engages with a resilient retaining member  26  at the inside end of the outside channel  16  to retain the drawer  12  in a closed position until the holding force associated with the resilient member  26  is overcome by pulling outwardly on the drawer  12  to release channel  20  from member  26 .  
         [0023]    The mechanism for providing the sequential operation of the channels is comprised of a resilient, elastomeric arm  30  mounted on the intermediate channel  18  so as to engage with a stop surface  32  of the inside channel  20  when the channels  18  and  20  are moved toward the open position. The resilient arm  30  includes a projecting pin actuator or lug  34  that extends into the pathway of a raceway  17  provided between the outside channel  16  and intermediate channel  18 . The raceway  17  includes a cam pathway  40  in FIG. 5 and FIG. 3 which engages the projecting pin actuator or lug  42 , moves the arm  30  by flexing the arm  30  in a manner which releases the projecting lug  42  of the arm  30  from engagement with surface  32  of inside channel  20  to thereby release the channel  20  as the assembly of the intermediate channel  18  and inside channel  20  move toward the drawer open position.  
         [0024]    Referring therefore to the figures, intermediate channel  18  includes the flexible arm  30  attached thereto by a rivet or fastener  44 . Flexible arm  30  flexes about its length as a cantilever beam. A flex point in the described construction depicted is provided at a narrowed section  46  of the arm  30 . The arm  30  projects forwardly and defines a lug  42  which projects into the pathway of the inside channel  20 , and more particularly, the lug engaging surface of the channel  20 . The channel  20  includes a detent cutout section  48  at its inside end which is designed for cooperation with the elastomeric retention bumper  26 . Thus, as depicted in FIG. 7 when the channels  16 ,  18  and  20  are in the closed position, the detent section  48  engages with the bumper  26  which is attached by a metal tab  50  to the outside channel  16  to retain the three channels  16 ,  18 ,  20  in the closed position until the drawer  12  is engaged and pulled so as to release the detent  48  from the resilient bumper and retention member  26 .  
         [0025]    The sequence of operation of the assembly is depicted in FIGS. 4, 5 and  6  in greater detail. Referring to FIG. 4, the inside channel  20  is initially engaged by the intermediate channel  18  and moved in unison therewith as the two channels move to the left as depicted in FIG. 4. Such engagement is effected by virtue of the lug  42  engaging with the retention surface  32  of channel  18 . Thus, as the inside channel  20  is moved to the left in FIG. 4, the intermediate channel  18  likewise moves therewith pulled by lug  42  against surface  32 .  
         [0026]    [0026]FIG. 5 illustrates the subsequent sequential operation. Specifically, the lug  42  becomes disengaged from the stop surface  32  inasmuch as the projecting pin  34  is engaged by the raceway cam slot  40  of raceway  17 . The projecting pin  34  thus engages and rides into the slot  40 . This moves the lug  42  downwardly into the center of the detent slot  48  in the direction of the arrow in FIG. 5 thereby releasing the inside channel  20  from the intermediate channel  18 . The inside channel  20  may then be moved to the full open position. The intermediate channel  18  is effectively stopped in its movement by virtue of the engagement of the projecting pin  34  with the end  41  of the raceway slot  40 .  
         [0027]    [0027]FIG. 6 illustrates the operation of the slide as the intermediate channel  18  and inside channel  20  are moved to the closed position. The intermediate channel  18  moves so that the distal inside end  60  of the intermediate channel engages against the stop or bumper  26 . Subsequently, the inside channel  20  moves to the right in FIG. 6 so that the detent opening  48  is positioned to engage with the bumper or resilient stop member  26 . The movement of the inside channel  20  to the fully closed position, as shown in FIG. 7, permits the resilient biasing arm  30  to move in the direction of the arrow in FIG. 6. Such movement repositions the lug  42  for engagement with the stop surface  32 . That is the arrangement then when the component parts are in the position illustrated by FIG. 7. The lug  42  is in the position shown in FIG. 7 engaging with the stop surface  32 .  
         [0028]    With the construct of the present invention, it can be seen that a fewer number of parts are required to provide for sequential operation. A single biasing arm  30  having appropriate lugs  42  and pins  34  for cooperation with an existing raceway  17  construction associated with the outside channel  16  enables sequential control of the slide mechanism. Various alternatives and changes may be made without departing from the spirit and scope of the invention. The invention is therefore limited only by the following claims and equivalents thereof.