Patent Abstract:
A friction reducer is positioned between a bar component and a channel in which an edge of the bar is enclosed during relative motion between the bar and the channel. The friction reducer is made of a material that presents a lower friction surface upon which the relative motion occurs.

Full Description:
FIELD OF THE INVENTION  
       [0001]    The present invention relates to a friction reducer and to a sliding friction reducer between a bar component and a channel. 
       BACKGROUND 
       [0002]    Many mechanical devices have a moving mechanism that includes a bar component that slides within a channel that closely fits along long sides of the bar. The closeness of the fit between the bar and the channel impacts many functional aspects of the mechanism. For example, depending on the frictional characteristics of the material of the bar and the channel, an overly close fit may result in a mechanism that presents too much drag as the bar is moved in the channel. On the other hand, while a looser fit between the bar and the channel may result in easier sliding, the mechanism may rattle when moved or become jammed due to misalignment between the bar and the channel. When both the bar and the channel are formed from a relatively rigid material, such as metal, it is difficult to compensate for these variations in component interaction that routinely occur due to many reasons such as manufacturing tolerance stack up. 
       SUMMARY  
       [0003]    A friction reducer is positioned between a bar component and a channel in which an edge of the bar is enclosed during relative motion between the bar and the channel. The friction reducer is made of a material that presents a lower friction surface upon which the relative motion occurs. The friction reducer may be, for example, a tab that snaps onto the edge of the bar and covers the front, side, and back of the edge of the bar at spaced locations along the edge of the bar. The friction reducer may be, for example, an insert that fits into the channel at locations along the length of the channel and provides a close fitting slot in which the edge of the bar may ride. The friction reducer may be, for example, a substantially continuous strip that folds around the front, side, and back edge of the bar along its length. The friction reducer may be, for example, a substantially continuous lining of friction reducing material in the channel. 
         [0004]    Further features and advantages of the invention will become apparent from the following detailed description made with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    In the accompanying drawings, which are incorporated in and constitute a part of this specification, embodiments of the invention are illustrated, which, together with the description of the invention serve to illustrate the principles of this invention. The drawings and detailed description are not intended to and do not limit the scope of the invention or any subsequent claims in any way. Instead, the drawings and description only describe embodiments of the invention and other embodiments of the invention not described are encompassed by this disclosure of the invention. 
           [0006]      FIG. 1  is a perspective view of a sliding bar within a guide channel that is cut away to show a friction reducing tab installed on the sliding bar according to an embodiment of the present invention; 
           [0007]      FIG. 2  is a cross section of the sliding bar and guide channel of  FIG. 1 ; 
           [0008]      FIG. 3  is an exploded perspective view of the sliding bar and friction reducing tab of  FIG. 1 ; 
           [0009]      FIG. 4  is a perspective view of a tool storage cabinet that includes a sliding lock bar within a guide channel according to an embodiment of the present invention; 
           [0010]      FIG. 5  is a cut away view of a guide channel that includes friction reducing inserts according to an embodiment of the present invention; 
           [0011]      FIG. 6  is a cut away perspective view of a sliding bar that includes a friction reducing edge wrap according to an embodiment of the present invention; and 
           [0012]      FIG. 7  is a cut away perspective view of a guide channel that includes a friction reducing liner according to an embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE INVENTION  
       [0013]    The Description of the Invention merely describes preferred embodiments of the invention and is not intended to limit the scope of the specification or claims in any way. Indeed, the invention as described by the claims is broader than and unlimited by the preferred embodiments, and the terms in the claims have their full ordinary meaning. 
         [0014]      FIG. 1  illustrates a lock bar  62  that slides within a lock bar guide channel  94 . The lock bar  62  is formed by bending a metal strip  64  into a flanged V-shape into which drawer catches  67  are machined. The lock bar  62  is a particular type of bar component that can be used in practice of the present invention. It will be apparent to one of skill in the art that the friction reducers that will be described herein can be used with any type of bar component having edges that slide within a channel. As will be described in more detail below, the lock bar  62  is moved vertically within the lock bar guide channel  94  in response to movement of a key cylinder to selectively lock or unlock drawers in a lockable chest. Friction reducing tabs  81  are snapped onto the outer edge of the metal strip  64  periodically along its length. These friction reducing tabs  81  provide a reduced friction surface upon which the lock bar  62  slides within the lock bar guide channel  94 . 
         [0015]      FIG. 2  illustrates the friction reducing tabs  81  installed on opposing edges of the lock bar  62  and fitted into the lock bar guide channel  94  within an outer channel portion  82 . The friction reducing tabs  81  are made from a material, such as for example, nylon, that provides a low friction interface with the metal of the lock bar guide channel. In addition to providing a low friction interface, it may also be advantageous for the material of the tab  81  to have elastomeric qualities so that it may be compressed to some extent within the outer channel portion  82  to compensate for variations in the amount of clearance between the lock bar metal strip  64  and the outer channel portion  82 . 
         [0016]      FIG. 3  shows a friction reducing tab  81  in an exploded orientation relative the lock bar metal strip  64 . To facilitate installation of the friction reducing tabs, the lock bar metal strip includes notches  69  and tab mounting holes  68  along its edges. The friction reducing tab includes an ear  92  that is sized to snap into the mounting hole  68 . The ear  92  projects from a tab channel that is formed by a front tab wall portion  88 , an outer tab wall portion  87 , and a rear tab wall portion  89 . As can also be seen in  FIG. 2 , once the tab  81  is snapped into the mounting hole  68 , the tab channel fits within the notch  69 . The front, outer, and rear tab wall portions  87 ,  88 ,  89  protrude from the notch  69  and extend beyond the edge of the metal strip  64 . In this manner, the friction reducing tab  81  becomes the point of contact between the lock bar  62  and the guide channel  94 . In particular, the outer surface of the tab channel becomes a sliding interface surface that provides reduced friction. 
         [0017]      FIG. 4  is a perspective view of a lockable drawer chest  10 , such as for example, a tool chest with its walls in phantom. It should be appreciated that a chest is shown for exemplary purposes only, and that any other container could be used, such as for example, a tool cabinet. The chest  10  includes the lock bar  62  and lock bar guide channel  94  described above as well as the friction reducing tabs  81 . The use of the friction reducers between a lock bar and a lock bar guide channel is but one example of a sliding bar mechanism in which the friction reducing techniques discussed herein can be used. The chest defines a cavity in which drawers  38  are slideably mounted. The chest is lockable, such that the drawers can be locked in the closed position. The chest includes a key cylinder  32  that is rotatable upon insertion of a proper key. The lock bar  62  is moved between a locked position and an unlocked position by the actuator when the key cylinder  32  is rotated. When the lock bar is moved downward to the locked position, a catch  67  on the lock bar is aligned with the striker plate  72  to hold the drawer in the closed position. When the lock bar is moved upward to the unlocked position, the catch is not aligned with the striker plate and the drawer can be opened. 
         [0018]    The lock bar  62  is slideably retained in a lock bar channel  94  on the rear wall  28  of the chest. The lock bar channel is formed from a strip of metal and includes a pair of spaced rolled flanges that form the outer channel portion  82  and in which the side edges of the metal strip  64  are enclosed. The edges of the metal strip  64  include one or more notches  69 . As discussed above, friction reducing tabs  81  are pressed into the notches  69 . The friction reducing tabs are thicker than the metal strip  64  and therefore the lock bar rides on the friction reducing inserts  81  as it is moved within the lock bar channel  94 . The friction reducing inserts may be made from nylon or other suitable material. 
         [0019]      FIG. 5  illustrates an alternative friction reducer arrangement. Friction reducing inserts  181  are pressed into the outer channel portion  82  of the guide channel. The friction reducing inserts may be made of nylon or other suitable material. The friction reducing inserts are substantially U-shaped and are sized to be maintained in position by frictional engagement with the outer channel portion  82 . Locating features (not shown) around an outer surface of the insert may be provided that connect to mating features in the outer channel portion. An inner insert channel  183  provides a reduced friction surface upon which the metal strip rides when the lock bar is moved relative to the guide channel. 
         [0020]      FIG. 6  illustrates a substantially continuous friction reducing edge wrap  187 . The edge wrap  187  is U-shaped with an inner channel that closely fits around the edge of the metal strip  64 . The edge wrap may be made from nylon or other suitable material or may be coating of friction reducing material that is applied to the metal strip  64  in liquid form and cures to form the edge wrap  187 . An outer wrap surface  188  provides a reduced friction surface that slides within the outer channel portion  82  when the lock bar is moved relative to the guide channel. 
         [0021]      FIG. 7  illustrates a substantially continuous liner  189  that is fitted into the outer channel portion  82 . The liner  189  is U-shaped and configured to closely contain the metal strip  64  within an inner channel. The liner may be molded from nylon or other suitable material. An inner liner channel  190  provides a reduced friction surface upon which the metal strip rides when the lock bar is moved relative to the guide channel. 
         [0022]    While various aspects of the invention are described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects may be realized in many alternative embodiments not shown, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present invention. Still further, while various alternative embodiments as to the various aspects and features of the invention, such as alternative materials, structures, configurations, methods, devices, and so on may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adapt one or more of the aspects, concepts or features of the invention into additional embodiments within the scope of the present invention even if such embodiments are not expressly disclosed herein. Additionally, even though some features, concepts or aspects of the invention may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless expressly so stated. Still further, exemplary or representative values and ranges may be included to assist in understanding the present invention however; such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated.

Technology Classification (CPC): 4