Patent Document

FIELD OF THE INVENTION 
       [0001]    The present invention relates to sliding assemblies for mounting drawers in cabinetry. In particular, the invention relates to extension ball bearing slides with a durable, front mounted, adjustable drawer retainer mechanism which prohibits the inadvertent opening of a closed drawer. 
       BACKGROUND OF THE INVENTION 
       [0002]    Drawer slides mounted to cabinets and drawers for slidably moving a drawer in a cabinet are well known in the art. Drawer slides are typically constructed of two or more rails which are telescopically extendable. In standard practice, the outer most rail is the widest and is mounted to the stationary cabinet wall and encloses the inner rails. The innermost rail is typically mounted on the side or underneath the drawer piece. The rails usually incorporate ball bearings mounted in retainers and seated in races formed in the sides of the rails so that the rails may slide with respect to each other. This low friction provided by the rails allows the drawer to move between the open and closed positions with minimal effort. As a result, drawers are often closed rapidly and with excess force and have a tendency to rebound when closed. In cabinetry installed in mobile homes, recreational vehicles, or boats, the low friction provided by the rails allows unintentionally opening drawers during vehicle movement. 
         [0003]    U.S. Pat. No. 5,757,109 to Parvin discloses a telescopic drawer slide with a soft sequencing latch. The soft sequencing latch comprises a latch arm carried by a slide member. A spring arm extending from the latch arm in compressive contact with the slide member biasing the latch arm into engagement with a locking element on a second slide member and an actuator on a third slide member for disengaging the latch arm. The actuator disengages the latch arm by applying a force to the latch arm with a component oppositely directed and of sufficient magnitude to overcome the compressive spring force. Interaction of the locking element with the latching arm and the interaction of the actuator with the latching arm may both serve as frictional interfaces during slide operation. The device requires a component on each slide member and the latch arm is susceptible due to constant deformation and frictional forces. Further, the force applied by the soft sequencing latch is not adjustable. 
         [0004]    U.S. Pat. No. 6,244,678 to Dopp, et al. discloses drawer slide with front-mounted stop/anti-rebound mechanism. Two stop/anti-rebound pieces comprised of resilient arcuate segments are individually attached at the forward ends of a first rail and a second rail of the rail assembly. The stop/anti-rebound mechanism engages when the first and second rails are in a closed position and prevent the first and second rails from moving beyond a closed position. The force applied by the stop/anti-rebound mechanism is not adjustable. The stop/anti-rebound mechanism includes certain arcuate segments that are prone to failure due to repeated deformation. 
         [0005]    U.S. Pat. No. 6,435,636 to MacMillan discloses a cushion end stop detent member for a drawer slide having a set of cushioning arms, a detent projection, and a frictional ramp. The cushion and detent projection element is made from a resilient material and is attached to the inside of the outer rail of a three rail drawer assembly. The cushioning arms and the frictional ramp engage and cushion the movement of the middle rail. The detent projection cooperates with a receptor in the inner rail. The device is prone to wear and deteriorates over time due to friction and repeated deformation. The device is not adjustable. 
         [0006]    U.S. patent to Radke, et al. discloses a drawer slide assembly having an adjustable integral strike and catch mechanism. An adjustable strike is included on a first slide member. A catch is included on a second slide member. The strike and catch engage when the drawer is closed. A strike fastener allows for adjustment of the strike position. The strike is deformable and so is prone to wear due to frictional forces and repeated deformation. 
         [0007]    There is a need for a less expensive, less complicated, and easily installed alternative to prior art drawer slides which secure closure of drawers. The drawer retainer mechanism disclosed provides an inexpensive yet durable, front mounted device for securing a drawer which provides ease of installation and more durable components which increase the user life of the slide and reduce the frequency of required replacement. 
       SUMMARY OF INVENTION 
       [0008]    A preferred embodiment provides an extension ball bearing drawer slide assembly with stay closed mechanism. The preferred embodiment is an inexpensive alternative to prior art drawer slide assemblies which prolongs the usable life of the drawer slide assembly and the cabinet piece by providing a front mounted and adjustable stay closed drawer retainer mechanism. 
         [0009]    Accordingly, an embodiment of the apparatus includes a drawer slide assembly comprised of a fixed member, a middle member slidingly engaged with the fixed member via a set of linear bearings, a drawer member slidingly engaged with the middle member via a second set of linear bearings, and a drawer retainer mechanism attached to the drawer member and in adjustable contact with the fixed member. The fixed member is attached to the cabinet piece, and the drawer member is attached to the drawer piece of furniture. The drawer retainer mechanism is comprised of a frame attached to the drawer member, a housing seated in the frame, a detent fitted in the frame and spaced from one interior surface of the frame by a helical spring. The helical spring is centered on a screw threaded into the frame. The detent, biased by the helical spring, is urged upward by a raised indention in the race of the fixed member as the drawer is opened or closed. Once the detent passes the raised indention, the drawer retainer mechanism retains the drawer in a closed position and hence prevents the drawer member from opening without a sufficient force applied in the opening direction. 
         [0010]    An alternate preferred embodiment attaches the housing directly to the drawer member. A hole in the housing is threaded to receive a threaded plug to adjustably bias the detent against the raised indention. 
         [0011]    Those skilled in the art will appreciate the above-mentioned features and advantages of the invention together with other important aspects upon reading the detailed description that follows in conjunction with the drawings provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    In the detailed description of the preferred embodiments presented below, reference is made to the accompanying drawings. 
           [0013]      FIG. 1  is an isometric view of a preferred embodiment of a drawer slide assembly. 
           [0014]      FIG. 2  is an exploded isometric view of a preferred embodiment of a drawer slide assembly. 
           [0015]      FIG. 3  is an isometric view of a preferred embodiment of the housing and detent of the drawer retainer mechanism. 
           [0016]      FIG. 4  is a plan view from the underside of a preferred embodiment of the housing and detent of the drawer retainer mechanism. 
           [0017]      FIG. 5  is an elevation view of a preferred embodiment of the detent. 
           [0018]      FIG. 6  is a partial cross section view in a closed position of a preferred embodiment of a drawer slide assembly along line  6 - 6  of  FIG. 1 . 
           [0019]      FIG. 7A  is a cross section view of a preferred embodiment of a drawer slide assembly in an opened position. 
           [0020]      FIG. 7B  is a cross section view of a preferred embodiment of a drawer slide assembly between an opened and closed position. 
           [0021]      FIG. 7C  is a cross section view of a preferred embodiment of a drawer slide assembly in a closed position. 
           [0022]      FIG. 8  is a partial cross section view in a closed position of an alternate preferred embodiment of the drawer slide assembly. 
           [0023]      FIG. 9  is a partial cross section view in a closed position of an alternate preferred embodiment of the drawer slide assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0024]    In the descriptions that follow, like parts are marked throughout the specification and drawings with the same numerals, respectively. The drawing figures are not necessarily drawn to scale and certain figures may be shown in exaggerated or generalized form in the interest of clarity and conciseness. 
         [0025]    Referring to  FIGS. 1 and 2 , drawer slide assembly  100  is comprised of fixed member  102 , middle member  104 , drawer member  106 , and drawer retainer mechanism  108 . Each member  102 ,  104 , and  106  of drawer slide assembly  100  is generally C-shaped and includes a pair of races for housing ball-bearing assemblies. Fixed member  102  is mounted to the inside of the cabinet frame of a furniture piece having a drawer using common attachment hardware such as wood screws. Although three slides are shown, it is understood that a greater or lesser number of slides may be telescopically engaged with one another. 
         [0026]    Proximate the front end of fixed member  102  is raised indention  114  located in race  115  for engagement with drawer retainer mechanism  108 . Proximate the opposite end of fixed member  102  extends tab  112 . Bumper  110  is attached to tab  112 . In one embodiment, bumper  110  is formed of rubber or similar deformable yet resilient material and is frictionally held in place on tab  112  via a slot which tab  112  extends through. In other embodiments, bumper  110  is formed of nylon or Teflon®. 
         [0027]    Middle member  104  is slidingly engaged with fixed member  102  via a series of ball bearings  120  held in bearing retainer  124 . Drawer member  106  is slidingly engaged with middle member  104  via a second series of ball bearings  122  held in a second bearing retainer  126 . Drawer member  106  is mounted to the side of the drawer frame of the cabinet piece using common attachment hardware such as wood screws through a plurality of mounting holes. From rear end  107  of drawer member  106  extend arms  127  and  129  which define cavity  128 . Arms  127  and  129  are slightly angled towards one another resulting in the distance between them being smaller than the height of drawer member  106 . The distance between arms  127  and  129  is slightly less the width of bumper  110  so that when engaged, drawer member  106  is frictionally held adjacent bumper  110 . In a preferred embodiment, drawer retainer mechanism  108  is attached to the front facing end of drawer member  106  opposite arms  127  and  129  and cavity  128 . As this front mounted feature is preferred for easier maintenance and replacement, it should be understood that the desired effect of preventing the inadvertent opening of the drawer and the rebound of the closed drawer can be accomplished if drawer retainer mechanism  108  were to be mounted on rear end  107  of drawer member  106 . 
         [0028]    As seen best in  FIGS. 2 and 6 , drawer retainer mechanism  108  is comprised of frame  130  mounted to the front facing end of drawer member  106 , housing  140  contained in frame  130 , and detent  142  seated within housing  140 . Frame  130  includes flanges  134 ,  135 ,  136 ,  137 , and  138  which form a generally open-sided rectangular box. Flange  134  connects frame  130  to drawer member  106  via a weld or other connection means common in the art. Flange  135  opposes flange  134 . Flange  138  includes threaded hole  132 . Flange  138  opposes flanges  136  and  137 . Flanges  136  and  137  are separated by gap  141 . 
         [0029]    As seen best in  FIGS. 2 ,  3 , and  4 , housing  140  is comprised of center support  171 , walls  173  and  175 , base support  177 , and guide wall  179 . The center support, walls, base support and guide wall form cavity  170 . Hole  154  passes through center support  171  into cavity  170 . Slot  158  is provided in base support  177  and is located opposite from and axially aligned with hole  154 . Slot  158  includes open end  160 . Open end  160  is less in width than slot  158  thereby creating a stepped recess and retaining detent  142  within cavity  170 . Guide wall  179  includes guide ridges  190  and  192 . Guide ridges  190  and  192  are integrally formed raised ridges generally parallel to each other and parallel to the longitudinal axis of screw  144 . Housing  140  is preferably cast from plastic or similar lightweight yet durable material and is generally rectangular in shape. 
         [0030]    As shown in  FIG. 5 , detent  142  comprises a combined rectangular body  167  and rounded protrusion  166 . Detent  142  further includes hole  156  having bottom  157 . Channels  162  and  164  flank hole  156  and are spaced to slidingly engage guide ridges  190  and  192 . In one embodiment, Channels  162  and  164  contain lubrication to ensure unencumbered linear movement of detent  142  with respect to housing  140 . The axes of channels  162  and  164  are generally parallel with the axis of hole  156 . Detent  142  is preferably cast from plastic or similar lightweight yet durable material. In alternate embodiments, detent  142  is constructed of Delrin, nylon or Teflon®. 
         [0031]    Screw  144  includes threaded section  152 , spanner head  153 , and shaft  155 . Spanner head  153  is shaped to accept a torsional force from a spanner. Screw  144  adjustably attaches housing  140  and detent  142  to frame  130  as threaded section  152  engages threaded hole  132 . When assembled, screw  144 , threaded hole  132 , hole  154 , and hole  156  are axially aligned. Spring  146  surrounds shaft  155  and is simultaneously constrained by shaft  155 , hole  154  and hole  156 . In an alternate embodiment, shaft  155  is not necessary as spring  146  is constrained by holes  154  and  156 . Spring  146  passes through hole  154  and is seated in hole  156 . Spring  146  provides a bias between frame  130  and bottom  157  thus forcing detent  142  out of housing  140  and extending protrusion  166  through slot  158  and through gap  141 . 
         [0032]    As shown in  FIGS. 7A ,  7 B and  7 C, in use, a pair of drawer slide assemblies  100  are typically mounted one on each side of a drawer and to opposing inside surfaces of a cabinet piece. 
         [0033]    In an “opened” position as shown in  FIG. 7A , the front end of drawer member  106  is extended beyond the front end of fixed member  102 . Drawer retainer mechanism  108  is not engaged with raised indention  114  and bumper  110  is not wedged between arms  127  and  129 . As a result the drawer is free to slide in direction  220  to a fully open position. 
         [0034]    Referring to  FIG. 7B , during a closing sequence, a force applied in the closing direction shown by arrow  210  causes drawer member  106  and drawer retainer mechanism  108  to approach fixed member  102 . Because spring  146  is compressed between threaded section  152  and detent  142 , the bias of spring  146  tends to force detent  142  out of housing  140  thus extending protrusion  166  through slot  158  and between flanges  136  and  137  through gap  141 . Detent  142  is held within housing  140  by the result of the width of body  167  being wider than slot  158 . Once protrusion  166  contacts raised indention  114 , raised indention  114  forces protrusion  166 , against the bias of spring  146 , to move in a direction parallel to the longitudinal axis of screw  144  through gap  141  and slot  158  until protrusion  166  has retreated towards housing  140  enough to successfully bypass raised indention  114 . Guide ridges  190  and  192  engaged with channels  162  and  164  in cooperation with walls  173  and  175  prevent detent  124  from rotating or jamming within housing  140  during engagement with raised indention  114 . Simultaneously, as protrusion  166  clears raised indention  114 , arms  127  and  129  engage bumper  110 . After passing raised indention  114 , spring  146  forces protrusion  166  through slot  158  and gap  141  away from housing  140  until body  167  abuts housing  140 . 
         [0035]    The force required to open or close the drawer can be adjusted by adjusting the compression of the helical spring. The compression of spring  146  increases as threaded section  152  is advanced. As the compression of spring  146  increases, the force required to move protrusion  166  through slot  158  and gap  141  toward housing  140  also increases. Adjusting the position of threaded section  152  relative to detent  142  thus adjusts the force necessary to move protrusion  166  through slot  158 . Rotating screw  144  in a clockwise direction shortens the distance between threaded section  152  and detent  142  thus compressing spring  146  and thus requiring a greater force to open or close the drawer. Rotating screw  144  in a counter-clockwise direction lengthens the distance between threaded section  152  and detent  142  decompressing spring  146  and thus reducing the force necessary to open or close the drawer. 
         [0036]    During an opening sequence, a sufficient force is applied in the opening direction shown by arrow  220 . The opening force must overcome the frictional force between bumper  110  and arms  127  and  129 . Simultaneously, raised indention  114  forces protrusion  166 , against the bias of spring  146 , through slot  158 . Once protrusion  166  clears raised indention  114 , spring  146  forces protrusion  166  through slot  158  and gap  141  until body  167  abuts housing  140  and the drawer is free to slide to its fully opened position unencumbered. 
         [0037]    In a “closed” position as shown in  FIG. 7C , drawer retainer mechanism  108  works cooperatively with bumper  110  and arms  127  and  129  to prevent the drawer from inadvertently opening without a sufficient force applied in the opening direction, as shown by direction arrow  220 . The combination of drawer retainer mechanism  108  and bumper  110  and arms  127  and  129  further prevents the drawer from rebounding from the closed position. 
         [0038]    In an alternate preferred embodiment shown in  FIG. 8 , housing  140  is mounted on tab  194  and constrained on one side by flange  196 . Tab  194  extends from drawer slide  106 . Tab  194  is integrally formed with drawer slide  106 . Flange  196  is integrally formed with tab  194 . In another alternative embodiment, tab  196  is not present. Housing  140  is mounted on tab  194  using common attachment hardware such as welding, rivets, or machine screws or with a suitable epoxy adhesive. Plug  180  is threaded for engagement with threaded hole  182  and upon rotation advances or retreats through threaded hole  182 . Spring  146  is constrained by threaded hole  182  and hole  156  in detent  142 . Spring  146  is adjacent plug  180  and bottom  157 . Spring  146  biases detent  142  against raised indention  114 . Adjusting the position of plug  180  relative to detent  142  adjusts the compression of spring  146  and thus adjusts the bias of detent  142  against raised indention  114 . 
         [0039]    In an alternate preferred embodiment shown in  FIG. 9 , housing  140  is mounted on tab  194  and constrained by flange  196 . Flexible member  186  is wedged between center support  171  of housing  140  and detent  142 . Flexible member  186  is constructed of rubber or closed shell plastic shock absorbing foam or any resilient substance having compressive shock absorbing and rebounding features. Flexible member  186  biases detent  142  against raised indention  114 . 
         [0040]    It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.

Technology Category: 1