Progressive drawer slide

Abstract

The present invention relates to an improved drawer slide of the progressive type incorporating a pair of external channel members, one of which may be secured to the side of a drawer, the other external channel being affixed to the surface of a cabinet adjacent the drawer side, the mechanism including an intermediate channel. Each external channel is connected to the intermediate channel by a separate anti-friction bearing assembly for relative sliding movement, the intermediate channel member including a compressible traction member fixed against substantial bodily movement lengthwise of the intermediate channel, the traction member including drive portions in frictional engagement with opposed vertical surfaces of the external channels. At least one of the anti-friction bearing assemblies permits a degree of lateral movement between the components connected thereby, whereby the widthwise separation of the external channels may be varied. The compressed traction means, the drive surfaces of which are biased against the channels, urge the channels outwardly to the maximum spaced condition permitted within the clearance space provided in any particular installation. The slide members of the type described are thus able to compensate for substantial inaccuracies in installation and tolerance variations in the construction of the drawer and cabinet, while at the same time, due to the yieldable biasing forces exerted by the traction member, providing smooth and controlled operation of the drawer.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is in the field of drawer slides and more particularly slides having components adapted to be attached to the sides of a drawer and the adjacent surfaces of a cabinet, permitting the drawer to be shifted between extended and retracted positions relative to the cabinet.

2. The Prior Art

It is known to provide slides for mounting drawers to cabinets to facilitate relative movement of said parts. Drawer slides typically take the form of longitudinally extended metallic channel members affixed at appropriate positions on the cabinet and drawer sides, the channel members being provided with suitable anti-friction bearings coupling the channels for relative longitudinal movement.

In more advanced forms of slide mechanisms, as shown for instance in U.S. Pat. Nos. 2,675,277 and 3,451,730, the slide is formed of three separate channels, such slides being referred to as "progressive" slides. In three channel slide systems there is provided an intermediate channel or web disposed between a pair of external channels or webs, the last mentioned webs being fixed to the drawer and cabinet surfaces. A proportioning device carried by the intermediate slide is interposed between the external slides, assuring that upon opening and closing of the drawer, the three channel elements move in a predetermined desired sequence, i.e., progressively.

While the superiority of progressive, three element drawer slide devices over the more conventional two element devices is generally acknowledged, the use of such progressive units has been more or less restricted to the metal cabinetry field. The reason for such restriction lies in the fact, inter alia, that existing progressive slides provide very limited play in a lateral direction, i.e., in the direction perpendicular to the intended path of travel of the drawer. The absence of lateral play is not a substantial drawback in the metal cabinetry field where the material admits of manufacturing within a relatively close tolerance range.

Progressive slides have found little use in wooden cabinetry applications, due principally to the natural tendency of wood to shrink, swell, warp, etc., conditions which interfere with maintaining the degree of tolerance needed for the use of existing progressive slide structures.

SUMMARY OF THE INVENTION

The present invention is directed to an improved progressive slide device for drawer suspensions and the like, characterized by its adaptability for use in wooden cabinetry or other installations wherein close tolerances cannot be maintained.

The invention is further directed to a slide of the type described wherein smooth operation of the drawer may be expected notwithstanding tolerance variations or installation errors of a magnitude which would cause progressive slides heretofore known to bind, or operate in an unacceptable manner.

The suspension or slide of the present invention includes exterior channel members surrounding an intermediate channel, the exterior channel members each being connected to the intermediate member by anti-friction bearings, allowing the channels to be shifted from a nested side by side position to an extended position. The anti-friction suspension linking the channels is of such nature as to permit a significant degree of horizontal transverse movement between the external channel members which are to be connected to the drawer and the fixed portions of the cabinet.

The intermediate channel carries a traction member which is resiliently expansible and contractable in a horizontal plane, the traction member preferably being in the form of a continuous annulus or band having spaced drive portions engaging against vertically opposed vertical wall surfaces of the external channels.

The traction member is supported on the intermediate member in such manner that relative bodily movement between the traction and the intermediate member is prevented while permitting relative longitudinal movements between the drive portions of the traction member and the intermediate channel. By reason of the outward biasing forces exerted by the drive portions of the traction member, the external members are normally urged toward their maximum spaced-apart condition.

Inaccuracies in installation are automatically compensated for by movement of the external channels toward and away from each other as a result of the contractable and expansible nature of the traction member. Since the traction member in both its contracted and expanded condition is at all times under a degree of compression, the resultant structure is essentially free from any tendency toward looseness or rattling, vibratory movements of the channel members in all instances being damped by the stressed engagement of such components with the traction member.

A drawer suspended between a parallel pair of slides may, by reason of the simplicity of the slide structure, be readily removed and replaced in the cabinet. Additionally, attachment of the external channel components to the drawer and to the cabinet may be accurately and easily accomplished, without the necessity of providing complex jigs, etc., making the slides suitable for use by "do it yourself" craftsmen.

Accordingly, it is an object of the invention to provide an improved drawer suspension or slide of the progressive acting type.

It is a further object of the invention to provide a slide of the type described having the ability to compensate, to a substantial degree, for inaccuracies in the dimensions of a drawer or cabinet component within which the drawer is to be mounted, as well as for inaccuracies in attachment of the slide elements to the drawer and cabinet without detracting from the smooth operating characteristics of the drawer.

A further object of the invention is the provision of an apparatus of the type described including three channel elements longitudinally extensible one with respect to the other, the two external elements being in driving connection with a horizontally expansible and contractable stressed traction member supported on the intermediate channel, the traction member performing the double function of extending the channels in a proportioned relationship responsive to relative longitudinal movement of the inner and outer channels and yieldingly "floating" the drawer between the cabinet supported channels to provide a rattle-free, smoothly operating system susceptible of automatic accommodation to tolerance variations.

To attain these objects and such further objects as may appear herein or be hereinafter pointed out, reference is made to the accompanying drawings, forming a part hereof, in which:

FIG. 1 is a horizontal sectional view through a cabinet and drawer assembly incorporating as the suspension components a pair of drawer slides in accordance with the invention;

FIG. 2 is a vertical section taken on the line 2--2 of FIG. 1;

FIG. 3 is a sectional view similar to FIG. 2 with the drawer in the open position;

FIG. 4 is a fragmentary perspective view of the slide apparatus installed on a drawer;

FIG. 5 is a magnified vertical section taken on the line 5--5 of FIG. 2;

FIG. 6 is a magnified vertical section taken on the line 6--6 of FIG. 2;

FIG. 7 is a side elevational view of the slide assembly;

FIG. 8 is a fragmentary vertical section taken on the line 8--8 of FIG. 7;

FIG. 9 is a fragmentary vertical section taken on the line 9--9 of FIG. 7;

FIG. 10 is a fragmentary horizontal sectional view taken on the line 10--10 of FIG. 5;

FIG. 11 is a magnified horizontal sectional view of a latch assembly inter-connecting the drawer supported and intermediate channels;

FIG. 12 is a side elevational view of the latch of FIG. 11.

Turning now to the drawings, as best perceived from FIGS. 1 and 4, there is shown a desk or like cabinet 10 within which is mounted a drawer 11 or like member to be suspended between a spaced pair of slide assemblies 12 in accordance with the invention. While the slide assembly has been illustrated in connection with the mounting of a drawer, it will be appreciated that the suspension is adapted for a variety of comparable uses, including supporting of sliding shelves, file suspensions, etc.

The slide assembly 12 is comprised of three elongated channel members, to wit: a first external channel member 13 adapted to be secured to the stationary cabinet member; a second external channel member 14 intended to be secured to the drawer, and an intermediate channel member 15 interposed between the channels 13 and 14 and slidingly interconnecting the same. It will be understood that the channels may be reversed, with the external channel 13 secured to the moving element and the external channel element 14 secured to the fixed cabinet component, with minor changes in the connective hardware.

The channel member 14 preferably includes an elongated metal web 16 which has been folded or rolled longitudinally to form inwardly extending horizontal tracks 17, 18, the terminal edges of the tracks 17, 18 being defined by opposed lips 19, 20. The channel 14, adjacent its upper and lower edges 21, 22, respectively, is provided with attachment apertures 23, 23, through which attachment screws 24 extend, the screws being driven into the drawer for effecting the desired connection thereto of the channel 14. It will be appreciated that a multiplicity of apertures 23 and screws 24 are provided along the length of the channel 14.

The other external channel 13 is likewise formed of a longitudinally extending web, the web 25 being bent or rolled to define inwardly facing projections 26, 27. The undersurface 28 of the projection 27 and the upper surface 29 of the projection 26 are arcuate in vertical section, each of said portions 28 and 29 defining a part of a raceway for receiving ball bearings.

The channel 13 includes upper and lower flanges 30, 31 having formed therein spaced attachment apertures 32 for the receipt of attachment screws 33. Optionally but preferably, flanges 30, 31 extend a vertical distance above and below the margins 21, 22 of the flanges of the channel 14, the extent of such projection being calculated to correspond to the clearance between the upper and lower surfaces of the drawer and surrounding cabinetry. Where the channels are thus formed, the channel 14 may be attached to the drawers with its lower edge 22 flush with the drawer bottom, and the lower edge of channel 13 positioned over a ledge in the cabinet opening, thereby facilitating accurate heightwise location of the parts. Alternatively, as shown, the suspension may be mounted centrally of the drawer.

Intermediate channel 15, as best seen in FIG. 6, is formed of a bent or rolled metallic web which is generally in the form of a "U" in vertical section, the U being located with its connecting branch portion 34 vertically arrayed and its legs 35, 36 generally horizontally disposed. The upper surface 37 of the leg 35 and the lower surface 38 of the leg 36 are arcuate in vertical section, the arcuate portion 37 of the intermediate channel 15 and the arcuate portion 28 of the external channel 13 together forming a raceway within which is slidably mounted a series of ball bearings 39.

In similar fashion, arcuate portion 38 of the intermediate channel and arcuate portion 29 of external channel 13 form a raceway for a lower series of ball bearings 40.

Since the arcuate surfaces of the raceways conform closely to the arcuate configurations of the balls 39 and 40, the balls permit sliding translatory movement between the intermediate channel 15 and external channel 13, with only a limited amount of transverse or horizontal relative movement being permitted, due to the conforming curvatures of the balls and races.

As best seen in FIG. 7, the balls, when once installed within the raceways, are permanently confined as by tabs 41, 41 struck from the channel 13 and projecting into the path of the balls at the outer terminal ends of the raceways, tabs 42, 42 struck from the intermediate channel 15 at the inner terminal ends of the raceways preventing an escape of the balls in a rearward direction.

When the maximum extended position of the channels 13 and 15 is achieved, the balls are compacted between the tabs 41 and 42.

As best seen in FIG. 6, the connecting branch portion 34 includes a longitudinally extending recess 43. A pair of stub shafts 44 is mounted within horizontal apertures 45 formed through the recess, the recess providing clearance for the head 46 of the stub shafts. Each of the shafts 44 carries a roller member 47 rotatably mounted on the shaft, the roller preferably being formed of nylon.

As best seen in FIG. 6, the transverse dimension of the rollers 47 is substantially smaller than that of the trackway defined between the web 16 of channel 14 and the lips 19, 20, providing room for relative transverse movement between the rollers 47 and the surfaces 17 and 18.

From the foregoing description it will be evident that the external channel 14 may be shifted toward and away from the intermediate channel 15 a distance dictated by the amount by which the transverse extent of surfaces 17, 18 exceed the width of rollers 47. A relative lateral movement of up to about three sixty-fourths inch between the noted channels has been found suitable for most installations.

It will be appreciated that with a permitted relative movement of the magnitude mentioned, a substantial amount of chatter or unevenness in the extension and retraction of the drawer might be anticipated, especially if the opening and closing forces were not exerted substantially centrally of the drawer. In order to eliminate any tendency toward lateral shifting and, hence, to obtain smoothness of operation, and in order further to provide the desired progressive extension and contraction, the intermediate channel 15 is provided with a traction assembly 48, which is depicted in greatest detail in FIGS. 5 and 10.

The traction assembly 48 includes a vertical shaft 49 supported on the intermediate channel 15 between upper and lower horizontal ears 50, 51 struck from the material of the channel 15. The shaft 49 is secured between aligned apertures 52, 53 in the ears 50, 51, respectively. The shaft 49 forms a locating support for the traction band or wheel 54, which extends to both sides of channel 15 through the aperture resulting from formation of the ears 50, 51. The band 54 is preferably formed of a resilient, readily compressible, high friction substance having high plastic memory characteristics. While numerous materials may suggest themselves for use, a preferred material is a high quality neoprene rubber.

The traction member 54 is generally annular in its normal or unstressed condition and is provided with an internal, vertically directed aperture 55 which is preferably substantially oversized as respects the diameter of the vertical shaft 49. The traction member is in the form of an endless tread, and is preferably provided with a series of vertically extending, closely spaced ribs or corrugations 56 on its outer perimeter to augment the frictional contact between said outer perimeter and drive portions 57, 58, which drive portions comprise opposed vertical wall surfaces of the webs defining the external channels 13, 14, respectively.

As best understood from an inspection of FIG. 10, the dimensions of the traction member 54 are selected so as to maintain frictional contact between the periphery of the traction member and the wall surfaces 57, 58 in all spaced conditions of the external channels 13, 14. It will be appreciated that the traction member 54 will be under compression even when the channels 13, 14 are at their greatest spacing whereby the traction member exerts a continuous outward biasing force on the channels 13, 14.

The channels 13, 14 may be shifted toward each other within the tolerance limits provided by the anti-friction rollers, as previously set forth.

When the channels 13, 14 are moved closer together, the traction element 54 will assume a progressively less circular and more elongated configuration. The closer the channels 13, 14 are moved toward each other, the greater the compressive forces exerted on the traction member, the greater the length of flattened components of the traction member pressed against the drive surfaces 57, 58 and, as a consequence, the greater the frictional connection formed between the traction member and drive surfaces.

The action of the slide in the course of movement will next be described.

When the drawer, positioned as shown in FIG. 2, is pulled to effect extension thereof, the traction member 54 which is sandwiched between drive surfaces 57 and 58 will, as a consequence, be caused to be moved in the manner of a tank tread, i.e., will move in a horizontal plane relative to intermediate slide 15. Substantial bodily movement of the traction member relative to channel 15 will of course be prevented by shaft 49. The actual distance which the traction member 54 is moved will be precisely one half the distance which the lead edge of the drawer moves relative to the cabinet, whereupon it will be observed that the intermediate channel 15, by reason of its connection through shaft 49 to the traction member, will be progressively extended at a rate which is one half the rate of movement of the drawer relative to the cabinet. The movement of the channels of the slide assembly is thus effected in a progressive manner, whereby each channel is shifted in a predetermined ratio relative to each other.

As previously noted, the spacing between the drawer sides and side adjacent faces of the cabinetry may vary, due to swelling, shrinkage, warping or improper fabrication or installation. However, so long as the variations remain within the tolerance range provided by the sum of relative lateral movements between the components of the drawer slides, there will be no tendency toward binding. Moreover, in view of the constant expanding forces exerted by the traction wheel, notwithstanding the substantial lateral tolerances provided, the movement of the drawer will at all times have a smooth "feel" and be free from looseness or play, notwithstanding the extending or retracting forces exerted on the drawer may be applied eccentrically, i.e. not centrally of the drawer.

Preferably mechanism is provided which permits the drawer to be bodily lifted clear of the cabinet assembly. A latching mechanism L suitable for such purpose is shown in detail in FIGS. 11 and 12 as interposed between channels 13 and 14. It should be understood, however, that such mechanism may alternatively, and in some installations preferably, be located as shown in dotted lines L' (FIG. 4) as coupling channel 14 and intermediate slide 15 in the fully extended position of the drawer.

The latch mechanism includes a gravity pawl 59 pivotally mounted to the channel 14 on the pivot pin 60 extending outwardly from the channel. The pawl 59 is normally maintained by gravitational forces in its solid line position as shown in FIG. 12, a stop tab 61 limiting the amount of clockwise movement permitted the laterally directed latching tooth 62.

A cam strike 63 is fixed to the outermost end of external channel 13, the strike including an inwardly directed locking face 64 normally engaged by latching tooth 62. The outermost withdrawn limit of the drawer results in the tooth 62 engaging against the locking face 64.

Should it be desired bodily to remove the drawer, the release tabs 65 of the supporting slide mechanisms are pressed downwardly, tilting the latch assembly 59 against gravity to the dot and dash position, FIG. 12, whereupon channel 14 is freed from its connection with intermediate channel 15.

The drawer may be reinstalled by shifting the same inwardly, whereupon the under surface of the latching tooth 62 will ride up over the cam 63 and drop into the latching position. Return movement of the drawer into the cabinet will result in progressive return movements of the three channel components to their original or telescoped position by reverse action of the traction member.

From the foregoing it will be appreciated that there is provided, in accordance with the present invention, an improved drawer slide assembly having particular advantages for use in supporting drawers or the like in installations where substantial tolerance variations may be encountered. The slide incorporates the desired progressive action through the use of a traction member compressed between vertical drive faces on longitudinally and laterally shiftable channels to be affixed to the drawer and the cabinet.

The compressed traction member biased between the channels assures smooth operation of the drawer, notwithstanding the substantial lateral movement permitted between the channels. The traction member will thus be understood to perform the double function of effecting the desired progressive drive action and absorbing any tendency toward looseness resulting from the substantial lateral shiftability between the channel elements.

It will be evident to skilled workers in the art, in the light of the instant disclosure, that variations may be made without departing from the spirit of the invention and, accordingly, the invention is to be broadly construed within the scope of the appended claims.

Claims

Having thus described the invention and illustrated its use, what is claimed as new and is desired to be secured by Letters Patent is:

1. A self-compensating drawer slide of the progressive opening type comprising first and second elongated external channel members free of direct connection to each other adapted selectively to be attached to a drawer side and a cabinet surface adjacent said side, an intermediate channel interposed between said exterior channel members, said exterior channel members including vertical, opposed, parallel wall portions, first and second anti-friction bearing means interposed between said intermediate channel and said first and said second external channels, respectively, for enabling relative longitudinal sliding movement of said channels, at least one of said anti-friction bearing means comprising a vertically disposed roller means rotatable about a horizontal shaft fixed to one said channel, the other said channel including a horizontal track supported on said roller means, the width of said track exceeding the width of said roller means to permit relative horizontal movement between the channels connected by said at least

one anti-friction bearing means, a resilient, compressible traction member including a continuous tread having first and second opposed drive portions biased into frictional driving contact with a different one of said parallel wall portions, and mounting means on said intermediate channel securing said traction member against substantial bodily movement longitudinally of said intermediate channel while permitting relative longitudinal movements between said drive portions and said intermediate channel.

2. A drawer slide in accordance with claim 1 wherein said traction member comprises an annular band, said band being deformed from the normal annular condition when disposed between said parallel wall portions.

3. A drawer slide in accordance with claim 2 wherein said tread includes corrugations in contact with said parallel wall portions.

4. A drawer slide of the progressive type comprising a pair of exterior channel members to be selectively secured to a drawer side and to a parallel cabinet surface adjacent said side and an intermediate channel, first and second guide and support means interposed, respectively, between said intermediate channel and each of said exterior channels, at least one of said guide and support means comprising a roller mounted on a guide track, said roller being shiftable lengthwisely and widthwisely relative to said track to permit, in addition to longitudinal sliding movement, relative lateral movements between the intermediate channel and exterior channel connected by said one guide and support means, and a traction member carried by said intermediate channel and including a pair of oppositely moving drive portions, one said drive portion being in frictional driving connection with a portion of each of said exterior channel members, said traction member being resiliently expansible and contractable in a horizontal plane yieldingly to bias said drive portions and, hence, said external channels laterally away from each other, movement of said exterior channels toward each other being accommodated by contraction of said traction member.