DRAWER SLIDE

Abstract: A drawer slide formed by cold rolling metal strip and shaped, in cross section, to define mutually presented tracks (16a, 16b; 17a, 17b) for receiving and cooperating with rollers (13; 14) carried, in use, by a drawer or by a drawer receiving cabinet, a web portion (18; 19) integrally interconnecting said tracks, stop means (24) at one end of a channel defined by said web and its respective tracks, and a buffer (31; 51) associated with said stop means (24), characterised in that said buffer (31; 51) is constructed from a shock-absorbent resilient material and comprises a pair of faces (34a, 34b; 54a, 54b) which each abut, or are closely adjacent, a respective one of said tracks, and a recess (32; 52) which is presented towards said rollers and is of such a size and shape that, in use, a roller may at least partially enter therein and abut a surface of the recess, causing the buffer to be distorted between the roller and the tracks such that at least one of said pair of faces abuts its respective track and so transfers part of the energy of the relative movement of the slide and the roller to the track, so cushioning any impact on the stop means.

Description: DRAWER SLIDE This invention relates to a drawer slide for use in a drawer slide assembly in such items of furniture as filing cabinets and other items of office furniture or domestic furniture such as bedroom and kitchen drawer units and more particularly to roller stop buffers for use in such a drawer slide. Background of the Invention International Application W095/19724 (in the name of the inventor in relation to the present application) discloses an arrangement wherein a single drawer slide, at each side of a drawer, cooperates with rollers carried by the drawer and the carcass of the cabinet housing the drawer, slidably to support the drawer within the cabinet. Each drawer slide is formed at at least one end with an upstanding flange carrying a rubber or synthetic resin buffer which has a shock absorbing function at an end of the travel of the various components. It has been found that this arrangement is able to accommodate the standard slam open/close test (BS 4875 (1985) Part 7). When larger forces are applied, the upstanding flange on which the buffer is located may become bent and on subsequent opening or closing it is possible for the roller to become jammed between the buffer and the drawer slide. It is an object of the present invention to provide a drawer slide having an improved shock-absorbing capability which obviates or mitigates the above mentioned disadvantages. Summary of the Invention In accordance with a first aspect of the present invention there is provided a drawer slide formed by cold rolling metal strip and shaped, in cross-section, to define mutually presented tracks for receiving and cooperating with rollers carried, in use, by a drawer or by a drawer receiving cabinet, a web portion integrally interconnecting said tracks, stop means at one end of a channel defined by said web and its respective tracks, and a buffer associated with said stop means, wherein said buffer is constructed from a shock-absorbent resilient material and comprises a pair of faces which each abut, or are closely adjacent, a respective one of said tracks, and a recess which is presented towards said rollers and is of such a size and shape that, in use, a roller may at least partially enter therein and abut a surface of the recess, causing the buffer to be distorted between the roller and the tracks such that at least one of said pair of faces abuts its respective track and so transfers part of the energy of the relative movement of the slide and the roller to the track, so cushioning any impact on the stop means. Preferably, the buffer is so shaped that, in use, each of said pair of faces abuts its respective track as the roller enters therein. The surface of said recess may be defined by a single curved wall or it may be defined by at least a pair of walls having different radii of curvature. Preferably, the surface of said recess comprises a pair of rectilinear walls which diverge in the direction of the rollers. Said pair of walls may be connected at their end of closest convergence by a third wall which may be perpendicular to the tracks. Preferably, the angle between said first wall and said third wall is equal to the angle between said second wall and said third wall. Preferably this angle is between 1 10° and 120°. Most preferably this angle is 1 15°. Thus it is to be understood that said recess preferably has a truncated "V" cross-section. Preferably, the shape of each of said pair of faces of the buffer corresponds to the shape of the adjacent track. Preferably the surface of said recess is itself recessed at its regions of impact by the roller so as to accept and locate the roller periphery at impact. Preferably, said buffer is formed from a material having a shore hardness of greater than 45. More preferably, between 45 and 65. Most preferably said material is rubber. Preferably, the drawer slide also includes an additional pair of mutually presented tracks for receiving and cooperating with additional rollers carried, in use, by the drawer receiving cabinet or by the drawer, and an additional web portion integrally interconnecting said additional tracks, said additional web and additional tracks defining an additional channel. A stop means and associated buffer may be provided at each end of said channel and a stop means and associated buffer may be provided at one or both ends of said additional channel. According to a second aspect of the present invention, there is provided a buffer designed and adapted for use in a drawer slide, wherein a recess extends from a first face to a second face, and wherein the surface of said recess comprises a pair of non-parallel planar walls which diverge away from a base of said recess. Said planar walls may converge at one end, in which case the recess has a "V" cross-section, and the line of intersection of said walls defines the base of the recess. Said pair of planar walls may be connected at their end of closest convergence by a third wall, in which case said third wall defines the base of the recess. Preferably, said third wall is planar and the angle between said first wall and said third wall is equal to the angle between said second wall and said third wall and is between 110° and 120°. Most preferably this angle is 1 15°. Thus it is to be understood that said recess preferably has a truncated "V" cross-section. Preferably the surface of said recess is itself recessed at its regions of impact by the roller so as to accept and locate the roller periphery at impact. Preferably, the buffer includes a third and a fourth face which extend substantially perpendicularly to said first and second faces, and said third and fourth faces each have either a convex or concave cross-section. Brief Description of the Drawings One example of the present invention is illustrated in the accompanying drawings, wherein :- Figure 1 is a diagrammatic side elevational view, in section, of a drawer and cabinet showing, in the upper part of the view, the drawer closed, and in the lower part of the view the drawer open; Figure 2 is a diagrammatic perspective view showing, in part, a drawer slide according to the present invention; Figure 3 is a diagrammatic perspective view of a buffer forming part of the slide of Figure 2 in use; Figure 4 is a diagrammatic end elevational view of the buffer of Figure 3 located on the drawer slide of Figure 2; Figure 5 is a diagrammatic side elevation view showing the buffer of Figure 3 located on the drawer slide of Figure 2; Figure 6 is a diagrammatic perspective view of an end region of the drawer slide; Figure 7 is a diagrammatic, partly exploded, perspective view of the drawer slide concentrating on the lower tracks, and Figures 8 and 9 are enlarged perspective views of a resilient buffer of the lower tracks of the drawer slide. Detailed Description of Preferred Embodiments Referring first to Figure 1 of the drawings it can seen that the drawer structure 1 1 is slidably supported within a cabinet carcass 12 by means of rollers 13 and 14 carried by the drawer and the cabinet respectively, the rollers cooperating with a drawer slide 15. There is a similar drawer slide and roller arrangement at each side of the drawer, and it can be seen that a pair of spaced rollers 13 is carried by the side wall of the drawer 1 1 aligned horizontally above a pair of spaced rollers 14 carried by the side wall of the cabinet carcass. It can be seen that the drawer 1 1 is supported by the cabinet, through the intermediary of the slide 15 throughout the whole of its travel between its fully closed and its fully open position, the length of the slide and the spacing of the rollers determining the length of the drawer travel. Referring now to Figure 2, the slide 15 is formed by a cold rolling operation from mild steel strip. In cross-section the slide 15 is basically an S-shape the upper curve of the S defining a pair of parallel, mutually presented, concave, upper tracks 16 cooperating with the rollers 13 (not shown), and the lower curve of the S defining a pair of spaced mutually presented, convex, lower tracks 1 7 cooperating with the rollers 14. More specifically the edge of the slide 15 which will be uppermost in use is, in cross-section, shaped to a part circular form to define the top track 16a of the concave upper tracks 16. The curve of the track 16a is arranged with its concave face presented vertically downwardly, and an integral, vertically extending web 18 lies between the rollers 13 (not shown) and the side wall of the cabinet in use and integrally unites the top track 16a with an intermediate region of the slide 15, which defines the lowermost concave track 16b of the upper tracks 16 and the top track 17a of the lower tracks 17. The' intermediate region defines a mirror image of the track 16a so that the concave face of the track 16b is presented vertically upwardly, and the convex outer face of the strip at that point defines the track 17a. At the termination of the tracks 16b and 17a the strip is bent through approximately 180° to define a second web 19. The web 19 extends vertically downwardly in use between the rollers 14 and the side wall of the drawer 11 and at its lower edge the strip is bent to form a convex rib defining the bottom track 17b of the lower tracks 17, the free edge being bent underneath the rib to form a flange 21 lying generally at right angles to the web 19. The tracks of the slide 15 are shaped to cooperate with the treads of the rollers, and thus the rollers 13 carried by the drawer have, in transverse cross-section, a convex, generally part-circular, periphery while the rollers 14 have, in transverse cross-section, a concave, generally part-circular, periphery. In practice the radius of curvature of the concave tracks 16 will be slightly larger than the radius of curvature of the convex rollers 13 and the radius of curvature of the convex tracks 17 will be slightly smaller than the radius of curvature of the concave rollers 14 so that the rollers can centre themselves within their respective tracks without binding. Both ends of the channel defined by the tracks 16 and the web 18 are closed by integral, upturned flanges 24 (only one shown); and one end of the channel defined by the tracks 17 and the web 19, the end which is innermost during use of the slide, is closed by an integral upstanding flange (not shown), the opposite end of the channel being open. It will be understood that the drawer slide at the opposite side of the drawer 1 1 is a mirror image of the drawer slide described above. Referring now to Figure 3, a buffer 31 is constructed of rubber having a shore hardness of between 45 and 65, and preferably 50 in the arrangement illustrated. One face of the buffer 31 has a recess 32 extending across its width. The walls of the recess 32a, 32b and 32c are linear and in its depth dimension the recess has a truncated "V"-section. The angles between walls 32a and 32b and walls 32b and 32c are 1 15° thus defining a "V'-angle (the angle between walls 32a and 32c at the point where they would converge) of 50°. A cut out 33 is provided through the main body of the buffer 31 in the same direction as the direction of extension of the recess 32 and corresponds in size and shape to the upstanding flange 24. An upper wall 34a and lower wall 34b of the buffer are convexly curved, mirroring the curves of tracks 16a and 16b respectively. Referring now to Figures 4 and 5, the buffer 31 is shown in position on the drawer slide ready for use, mounted on the flange 24 of the upper tracks which is outermost in use of the slide, the flange 24 being received in the cut out 33. Flexure of the buffer 31 is needed in order for it to be able to pass the free edge of track 16a and the uppermost edge of web 19 when mounting it on the flange 24, whereafter the buffer sits in the channel defined by tracks 16a and 16b and web 18 and is retained therein, with walls 34a and 34b in contact with tracks 16a and 16b respectively. A similar buffer could be provided on the opposite flange 24 (at the innermost end of the slide) but in practice a relatively simple, conventional, buffer in the form of a rubber block having a concave face presented to the rollers 13 is sufficient since this flange 24 does not accept impact loadings in normal use. Preferably a revised buffer 51 (as described below with reference to Figures 7, 8 and 9) operating on the same principle as the buffer 31 will be utilised in conjunction with the flange of the lower tracks 17. In use, rollers 13 and 14 travel along their respective tracks 16 and 17 and at one end of their travel each front roller 13 impacts with the respective buffer 31 . For conventional drawer slides, if the impact force is high, for example if the drawer is slammed open, there is a danger that the drawer slide will be damaged, possibly resulting in jamming of the cabinet drawer. A resilient buffer is traditionally provided to absorb some of the impact energy by compression. However, most of the force is directed against the upstanding flange which tends to bend. The buffer is then no longer located along the path of the rollers but sticks out, away from the tracks. Subsequently, the roller may become wedged behind the buffer, or the buffer may detach itself from the flange. The drawer slide of the current invention can withstand a much greater force without damage because the first points of impact of the roller 13 with the buffer 31 are on walls 32a and 32b. The buffer distorts and becomes wedged between the roller 13 and the tracks 16a and 16b. This has the effect of directing a proportion of the impact force into tracks 16a and 16b orthogonally to the direction of travel of roller 13. The construction of the drawer slide is such that much greater forces in this direction can be tolerated without deformation than forces applied to the relatively weak upstanding flange 24 in the direction of travel of the roller 13. In addition, the tendency of the flange 24 to bend is further reduced because the buffer 31 is forcibly pressed into tracks 16a and 16b respectively and thus the buffer 31 and the flange 24 are held in position. The walls 32a, 32c of the buffer 31 are each formed with a recess 35 at the point of impact of the respective roller 13, the actual position of the recesses 35 being determined by the diameter of the roller relative to the width of the opening 32 of the buffer. The recesses 35 receive the periphery of the roller at impact and resist any tendency for the roller to skid on the surface of the buffer walls or for the roller or the buffer to be deflected laterally. Thus the impact force flexes the buffer into the tracks 16a, 16b which absorb a proportion of the impact loading. The rear shoulders 36 of the buffer are cut away to assist assembly of the buffer to the slide. Moreover to accommodate strengthening ribs pressed in the flange 24 and/or web 18 the buffer is formed with corresponding grooves 37. Conventional drawer slides are formed with a cut-out region in the track 16a to permit assembly of the slide to the rollers 13. However such a cut-out would move part of the support for the buffer 31 and to avoid this the outer wall of the track 16a is flared outwardly adjacent its end (as shown at 41 in Figure 6) to provide a clearance to facilitate assembly of the slide to the rollers 13. The assembly described above can exceed level 4 of the BS 4875 (1985) Part 7 slam open/closed test. Referring now to Figures 7, 8 and 9 there is illustrated a corresponding form of buffer 51 for use with the tracks 17 to cushion the impact of a roller 14 at one end of the travel of the rollers 14 relative to the track 17. Although only one roller is shown in Figure 7 it will be recognised that in practice there will be two rollers spaced apart along the length of the slide. The buffer 51 is constructed of rubber having a shore hardness of between 45 and 65, and preferably 50 in the arrangement illustrated. The buffer 51 is generally in the form of a block of rubber which seats between the upper and lower tracks 17a, 17b and which is held against longitudinal movement relative to the slide 15 by the flange 24 upstanding between the tracks 1 7a, 17b. The flange 24 is formed, as illustrated in Figure 1 , with strengthening ribs which extend around the right angle where the flange 24 merges with the web of the slide 15 interconnecting the tracks 17a, 1 7b, and the buffer 51 has a correspondingly shaped cut out 53 extending therethrough to receive the upstanding flange 24. The upper and lower walls 54a, 54b of the buffer are grooved along their length, so as to be of concave cross-section and thus to seat on the convex tracks 17a, 17b respectively. The front face of the buffer 51 , presented in use to the roller 14 defines a recess 52 of truncated V-shape. Thus the upper and lower walls 52a, 52b of the recess 52 are inclined inwardly from the walls 54a, 54b and converge towards the centre line of the buffer. However, prior to convergence the walls 52a, 52b terminate in a base wall 52c parallel to the flange 24. In addition, in transverse cross-section, the wall of the recess 52 includes an upstanding rib 55 of part-circular cross-section and of a radius of curvature such that it can be received within the groove of the concave roller 14. In use, as the slide 15 moves relative to the roller 14 to bring the rollers 14 towards the flange 24 the roller enters the recess 52 of the buffer 51 and the rib 55 of the wall of the recess 52 enters the peripheral groove of the roller 14. Continued relative longitudinal movement drives the roller further into the recess 52 and the inclined upper and lower walls 52a and 52b of the recess 52 are thus flexed outwardly by the entry of the roller 14. The outward flexure of the buffers 51 is resisted by the tracks 17a, 17b and thus the buffer 51 serves to cushion the impact of the roller 14 at the end of the relative travel of the roller 14 and the slide 15, and the impact loading is transmitted, at least in part, to the tracks 1 7a, 1 7b rather than being accepted exclusively by the flange 24. It will be recognised therefore that the buffer 51 operates in a manner similar to the buffer 31 of the tracks 16 as disclosed above. Whereas there may be buffers at both ends of the tracks 16 of the slide 15, it is only necessary to provide a flange 24 and buffer 51 at one end of the tracks 1 7 where the rear roller 14 coacts with the end of the slide as the drawer is slammed open relative to the carcass of the cabinet. When the drawer is moved to its shut position the outermost roller 14 will not normally reach the end of the slide 15, and thus a flange 24 and buffer at that end of the track 17 is unnecessary for most applications. It will be recognised that as an alternative to the recess 32 (52) having rectilinear walls, it could be defined by a single curved wall or it may be defined by at least a pair of walls having different radii of curvature.

Claims: CLAIMS 1. A drawer slide formed by cold rolling metal strip and shaped, in cross-section, to define mutually presented tracks (16a, 16b; 17a, 17b) for receiving and cooperating with rollers (13; 14) carried, in use, by a drawer or by a drawer receiving cabinet, a web portion (18; 19) integrally interconnecting said tracks, stop means (24) at one end of a channel defined by said web and its respective tracks, and a buffer (31 ; 51 ) associated with said stop means (24), characterised in that said buffer (31 ; 51 ) is constructed from a shock-absorbent resilient material and comprises a pair of faces (34a, 34b; 54a, 54b) which each abut, or are closely adjacent, a respective one of said tracks, and a recess (32; 52) which is presented towards said rollers and is of such a size and shape that, in use, a roller may at least partially enter therein and abut a surface of the recess, causing the buffer to be distorted between the roller and the tracks such that at least one of said pair of faces abuts its respective track and so transfers part of the energy of the relative movement of the slide and the roller to the track, so cushioning any impact on the stop means. 2. A drawer slide as claimed in claim 1 characterised in that the buffer is so shaped that, in use, each of said pair of faces (34a, 34b; 54a, 54b) abuts its respective track (16a, 16b; 17a, 17b) as the roller (13; 14) enters therein. 3. A drawer slide as claimed in claim 1 or claim 2 characterised in that the surface of said recess (32; 52) is defined by a single curved wall or by at least a pair of curved walls having different radii of curvature. 4. A drawer slide as claimed in claim 1 or claim 2 characterised in that the surface of said recess comprises a pair of rectilinear walls (32a, 32c; 52a,52c) which diverge in the direction of the rollers. 5. A drawer slide as claimed in claim 4 characterised in that said pair of walls (32a, 32c; 52a,52c) are connected at their end of closest convergence by a third wall (32b; 52b) which is perpendicular to the tracks. 6. A drawer slide as claimed in claim 5 characterised in that the angle between said first wall and said third wall is equal to the angle between said second wall and said third wall. 7. A drawer slide as claimed in claim 6 characterised in that said angle is between 1 10° and 120°. 8. A drawer slide as claimed in claim 7 characterised in that said angle is 1 15°. 9. A drawer slide as claimed in any one of the preceding claims characterised in that the shape of each of said faces (34a, 34b; 54a, 54b) of the buffer corresponds to the shape of the adjacent track (16a, 16b, 17a, 17b). 10. A drawer slide as claimed in any one of the preceding claims characterised in that said first and second walls of said recess (32) are recessed at regions (35) of impact by the roller (13) so as to accept and locate the roller periphery at impact. 1 1. A drawer slide as claimed in any one of the preceding claims 1 to 9 characterised in that said first and second walls are convex to cooperate with a concave roller. 12. A drawer slide as claimed in any one of the preceding claims characterised in that said buffer is formed from a material having a shore hardness of greater than 45. 13. A drawer slide as claimed in any one of the preceding claims characterised in that said buffer is formed from a material having a shore hardness of between 45 and 65. 14. A drawer slide as claimed in any one of the preceding claims characterised in that said material is rubber. 15. A drawer slide as claimed in any one of the preceding claims characterised by an additional pair of mutually presented tracks (17) for receiving and cooperating with additional rollers (14) carried, in use, by the drawer receiving cabinet or by the drawer, and an additional web portion (19) integrally interconnecting said additional tracks, said additional web and additional tracks defining an additional channel. 16. A drawer slide as claimed in any one of the preceding claims characterised by stop means (24) and associated buffer (31) provided at each end of said channel and a stop means (24) and associated buffer (51 ) provided at one or both ends of said additional channel. 1 7. A shock-absorbent resilient buffer designed and adapted for use in a drawer slide, characterised by comprising a pair of faces (34a, 34b; 54a, 54b) which each abut, or are closely adjacent, a respective one of roller receiving tracks (16a, 16b; 17a, 17b) of the slide, and a recess (32; 52) which is presented towards rollers (13; 14) of the slide assembly in use and is of such a size and shape that, in use, a roller may at least partially enter therein and abut a surface of the recess, causing the buffer to be distorted between the roller and the tracks such that at least one of said pair of faces abuts its respective track and so transfers part of the energy of the relative movement of the slide and the roller to the track.

Inventors: MUNACHEN RICHARD N, MUNACHEN, RICHARD, N.
Applicants: METSEC PLC, MUNACHEN RICHARD N, MUNACHEN, RICHARD, N.
Application year: 1998
Main classification: A47B88
IPC codes: A47B88