Abstract:
A locking and release mechanism for a slide assembly comprised of multiple telescoping channel members interacting, opposing cantilever springs mounted on the telescoping slides or channel. The mechanism can be made of plastic, spring steel or other alternative materials. The mechanism can be used on ball bearing or friction telescoping drawer slide assemblies.

Description:
BACKGROUND OF THE INVENTION 
     In a principal aspect the present invention relates to a mechanism, incorporated in a drawer slide assembly having multiple telescoping slide channels for locking one telescopic, slide channel or member in an extended position in a second slide channel and subsequently manually release the telescoped slide channel from its locked and extended position by means of a manual release construction which avoids exposure to a pinch point. 
     Multiple drawer cabinets for office storage and the like include drawers that are typically mounted on slide assemblies comprised of two or more nesting, telescopically movable slide channels or members which are attached respectively to the inside of a cabinet housing and the outside of the drawer. Various types of such slide assembly mechanisms have been developed to facilitate the safe and efficient movement of drawers between a drawer closed position and a drawer open position. 
     Often it is desirable to open a drawer and maintain the drawer in the open position as the contents of the drawer are reviewed or accessed. Various mechanisms incorporated in the slide assembly have been proposed for maintaining drawers in an open, locked position. Typically such mechanisms require manual release and thus exposure of the individual using the drawer to pinch points associated with the locking mechanism for the slide assembly. Development of a locking and release mechanism for a slide assembly which minimizes or avoids exposure of individuals to pinch points is thus a desirable objective and one motivation for development of the present invention. 
     SUMMARY OF THE INVENTION 
     Briefly, the present invention comprises a locking and release mechanism for a drawer slide which provides for automatic locking of a multiple channel slide assembly in an extended position and manual release when in the extended position. 
     Thus the slide assembly will include at least a first or outer slide channel and a second or inner slide channel which telescopically slides in the outer slide channel in a longitudinal axial direction. Each of the slide channels includes a center span or web. The center webs are in opposed, generally parallel relation to one another and slide longitudinally with respect to each other as the channels slide. The inner slide channel includes a first cantilever spring mounted on the central web with an active biased end that extends into the pathway of the center web of the outer slide channel when the inner slide channel is moved to the extended position to block or preclude movement of the inner channel slide to the retracted position once the inner slide channel has been extended. In order to release the first cantilever spring associated with the inner slide channel, a second cantilever spring is mounted on the center web of the outer slide channel. The second cantilever spring includes a prong which extends over the end of the outer slide channel in alignment with the longitudinal axis and opposed to the first cantilever spring mounted on the inner slide channel. The prong may be manually actuated to move toward and engage the first cantilever spring on the inner slide channel and thereby release it from blocking movement of the inner slide channel telescoping into the outer slide channel. Because the prong overlies the end of the outer slide channel, the described arrangement precludes exposure to a pinch point associated with the outer slide channel and, in particular, with the region of engagement of the outer slide channel with the first cantilever spring mounted on the inner slide channel. 
     Thus it is an object of the invention to provide an improved slide assembly having a feature which locks the slide assembly in an extended position while providing a safe and efficient release mechanism to enable release of the slide assembly from the extended position. 
     Another object of the invention is to provide a simple, effective, unobtrusive, and accessible mechanism for slide assemblies which will lock the assembly in an extended position and yet provide for easy release from the locked position. 
     Another object of the invention is to provide a locking and release mechanism for slide assemblies which may be easily incorporated in slide assemblies of the type hereto manufactured without significant modification. 
     These and other objects, advantages and features of the invention will be set forth in the detailed description that follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In the detailed description which follows, reference will be made to the drawing comprised of the following figures: 
     FIG. 1 is an isometric view of the locking and release mechanism for a drawer slide assembly; 
     FIG. 2 is an exploded isometric view of the assembly of FIG. 1; 
     FIG. 3 a  is a cross sectional view of the locking and release mechanism as incorporated in a drawer slide with slide channels in the locked position; 
     FIG. 3 b  is a cross sectional view similar to FIG. 3 a  wherein the release mechanism has been actuated to effect release of the slide channels with respect to one another; 
     FIG. 3 c  is a cross sectional view illustrating a further sequence in the operation of the release mechanism and wherein the slide channels have been moved longitudinally one with respect to the other; 
     FIG. 4 is a side elevation of the release cantilever spring; 
     FIG. 5 is a top elevation of the spring of FIG. 4; 
     FIG. 6 is an isometric view of the spring of FIG. 4; 
     FIG. 7 is an isometric view of the locking spring; and 
     FIG. 8 is a cross sectional view of the assembly taken along the line  8 — 8  in FIG. 3 a.    
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The figures illustrate a typical telescopic slide assembly which includes a first or outer slide channel or member and second or inner slide channel or member  12 . The inner slide channel  12  telescopically slides within the outer slide channel  10 . The outer slide channel  10  includes a central web or plate  14 . Similarly, the inner or second slide channel  12  includes a central web or plate  16 . The inner slide channel or slide  12  slides longitudinally in a direction along an axis  18  within the first or outer slide or slide channel  10 . The outer slide  10  is typically connected to an inner drawer cabinet wall, for example, or alternatively is incorporated in a further slide channel that is attached to an inner cabinet wall. The inner slide or second slide  12  is attached to the outside of a drawer. Thus as the drawer is opened, the inner slide or second slide  12  will move in the direction indicated by the arrow in FIG. 1 along axis  18  and telescopically extends from the first or outer slide  10 . 
     The embodiment of the invention includes a mechanism which will maintain the inner or second slide  12  in an extended position. This mechanism comprises a cantilever spring  20 . The cantilever spring  20  includes a first end  22  which is fastened to the web  16  of the second or inner slide  12 . The cantilever spring  20  includes a second active or free end  24  which is biased away from the web  16  by virtue of the spring effect of the cantilever spring  20 . The active or free end  24  of the spring  20  projects into the pathway against an end stop  15  of the first or outer channel  10  when the inner channel  12  is moved to a desired, extended position. Thus by positioning the cantilever spring  20  appropriately on the web or plate  16  a designer may provide that when slide  12  is moved to an extended position, it cannot be retracted into the outer channel or outer slide  10 . 
     In order to release the engagement of the active end  24  of the cantilever spring  20  it is necessary to bias or move the spring  20  so as to disengage the active end  24  from the end stop  15  of web  14  of channel  10  and, more particularly, from the end of the web  14  of the first channel or slide member  10 . This disengagement is accomplished by means of a release lever or second cantilever spring  30 . 
     The second cantilever spring  30  includes the first end  32  which is fastened to the central web  14  of the outer slide  10  and a second movable, active end  34  having a prong or arcuate section  36  at its active end  34 . The cantilever release spring  30  will typically be biased out of engagement with any of the slide members  12  or  14 . However, in order to release the spring  20 , prong  36  may be manually engaged and depressed against the spring force of the cantilever spring  30  thereby engaging the first or locking spring  20  to release the end of spring  20  from engagement from the end of the web  14  of the inner slide  10 . The inner slide  12  or second slide  12  may then be longitudinally telescoped into the outer slide  10 . 
     It should be noted that the release lever or release spring  30  is a cantilever spring and that the prong  36  is shaped in a manner to avoid exposing operator of the spring to the pinch point which is defined as the intersection between the end of the web  14  and the active end  24  of the spring  20 . Thus, utilization of the release spring  30  as designed avoids exposure of an individual to a potential hazardous situation to effect release of the locking mechanism. 
     In the embodiment it is preferred that the cantilever springs  20 ,  30  be aligned longitudinally along the longitudinal axis  18  on the respective webs  14  and  16  and that the active ends of each of the cantilever springs  20 ,  30  are in opposed relationship. However, it is possible to reverse the construction of the locking spring  20  by providing a tab (not shown) which would project upwardly and into the pathway of the end or web  14  of the outer channel  10 . The release mechanism to for such a configuration would be substantially the same as depicted for the construction of the locking spring  20 . 
     The materials which are utilized to provide the spring mechanism may be spring steel, plastic, or other alternatives. Further, the mechanism is useful for various types of drawer slides having two or more nesting slides. Thus the mechanism may be used on ball bearing or friction telescoping drawer slides. Various other alterations and changes to the design and construction of the invention are possible. Thus the invention is to be limited only by the following claims and equivalents thereof.