A BALL SLIDE SYSTEM

Abstract: For supporting a drawer in a filing cabinet an inner runner 11 runs on three sets of balls 13, 14 and 15 within an outer runner 10. The balls are supported by a cage 12. The three sets of balls are in a triangular disposition and the inner runner has lobes 22 and 23 extending across the sides of the triangle between the balls and a stem 21 which passes be­ tween the balls 14 and 15 and emerges through a slot be­ tween edges 19 and 20 of the outer channel-section runner 10.

Description: The present invention relates to a ball slide system of the kind which is used, for example, to support drawers in filing cabinets. Conventional ball slides normally have upper and lower ball races which provide good support for the weight acting in a vertical plane but are weak in a direction perpendicular to the plane of the ball races. European Patent Specification EP-A-0158811 discloses a ball slide system comprising an inner runner an outer runner and three sets of balls interposed between the runners and arranged in a triangular array, as seen in the cross-section of the runners, the outer runner being shaped to provide three tracks for the three sets of balls and the inner runner being of Y shape in cross-section with a stem extending outwardly from the centre of the array between two sets of balls and through a slot in the outer runner and two arms extending outwardly from the centre of the array between the other pairs of sets of balls. The present invention as defined in Claim 1 characterized in that the balls are supported by a cage, the outer runner is of generally rectangular channel section with the base of the channel deformed to provide one ball track turned-in edges to the sides of the channel providing the other two tracks, and the inner runner is formed from sheet metal so that the two arms are of double thickness in the form of lobes extending outwards beyond the line joining the centres of the respective sets of balls and the angles between the stem and the arms and between the two arms rounded to form tracks for the three sets of balls. German Patent Specification DE-A-3323195 shows a rectangular channel section outer runner providing three tracks for a triangular array of balls supported by a cage but has a different form of inner runner providing for essentially vertical loads. German Patent Specification DE-A-3329541 shows a rectangular channel-section outer runner but has a rectangular array of balls in a rectangular cage with the balls running in the corners of the channel. In the ball slide system of the invention, the extension of the lobes of the inner runner between the sets of balls ensures that there is adequate bearing surface between the inner runner and the balls and a good distribution of load between the balls regardless of the direction of the load. In addition, the arrangement provides a good resistance to rotational movement of the inner runner within the outer runner and prevents the ball slide from tightening and becoming jammed. The resistance to rotation and the even distribution of load between the balls are improved if the sets of balls are arranged in an isosceles triangle or equilateral triangle, as seen in a cross-section. In the case of the isosceles triangle, the stem of the inner runner will extend from the base of the triangle. Preferred features of the invention are defined in dependent claims 2 to 6. Embodiments of the present invention will now be described with reference to the accompanying drawings in which:- Figure 1 is a cross-section of a single extension ball slide; Figure 2 is a cross-section of a double-extension ball slide; Figure 3 is a cross-section of a modified double-extending ball slide; Figures 4 and 5 show modifications of the ball slide of Figure 1. Referring first to Figure 1, this shows an outer runner 10, an inner runner 11, and a ball cage 12 which supports three sets of balls 13, 14 and 15. The outer runner 10, which encloses the balls and the ball cage 12, is of generally rectangular channel section with two flat parallel sides 16 and 17 which serve for attachment of the runner 10 to a cabinet or other fixed support. The base 18 of the runner 10 is shaped to provide a track for the balls 13. The sides 16 and 17 are bent in at their edges 19 and 20 to provide tracks for the balls 14 and 15, respectively, and to retain the balls and ball cage within the outer runner 10. The inner runner 11 is of Y shape in cross-section with the stem 21 extending out through the slot between the edges 19 and 20 for attachment to a drawer or other member which is to be supported. The arms 22 and 23 of the Y extend between the pairs of balls 14, 13 and 13, 15, respectively. It will be seen that the inner runner 11 is formed from rolled steel so that the stem 21 and arms 22 and 23 are of double thickness and the angles between the stem and the arms and between the two arms are rounded to form tracks for the three sets of balls. It can be seen that by having each of the two arms of the Y in the form of lobes extending beyond the line joining the centres of the two respective sets of balls, there is adequate bearing surface between the inner runner and the balls to provide an even distribution of load between the balls. This ensures the ball slide will not tighten or become jammed when a load is applied that would tend to twist the inner runner. This makes it possible to use the ball slide in different orientations. In particular the ball-slide may be inverted without affecting its basic operation, though the loading on the balls will be different. Thus for a double-extension slide the structure of Figure 2 consists of a slide as described with reference to Figure 1 together with a similar slide in inverted position with the two inner runners formed integrally with one another. In Figure 2 the parts of the upper slide are given the same references as in Figure 1, while the corresponding parts of the inverted lower slide have the same references with 100 added, thus ball 114 corresponds to ball 14. The inner runner 11 is common to the two slides and comprises two Y shaped parts joined by their stems. To increase the clearance between a sliding drawer and the walls of the cabinet, for example, the double extension system shown in Figure 3 can be used. The inner runner 11a is formed with an offset crank 11b. The side 16 of the upper outer runner 10 may be attached to the drawer. The side 117 of the lower outer runner will then clear the side of the drawer by the length of the offset 11b. The offset crank 11b will also strengthen the inner runner 11a. Figures 4 and 5 show modifications of Figure 1 in which the top horns 24 and 25 of the outer runner have been extended to increase the bending moment of the runner. The central region 18 between the horns 24 and 25 still forms the track for the ball 13. In the case of Figure 5 a larger-size ball 13' is used which is of greater diameter than the balls 14 and 15. Both the inner and outer runners can be made of rolled steel or similar hard material or can be made as extrusions.

Claims: A ball slide system comprising an inner runner (11) an outer runner (10) and three sets of balls (13, 14, 15) interposed between the runners and arranged in a triangular array, as seen in the cross-section of the runners, the outer runner being shaped to provide three tracks for the three sets of balls and the inner runner being of Y shape in cross-section with a stem (21) extending outwardly from the centre of the array between two sets of balls (14,15) and through a slot in the outer runner and two arms (22,23) extending outwardly from the centre of the array between the other pairs of sets of balls characterized in that the balls are supported by a cage (12), the outer runner (10) is of generally rectangular channel section with the base (18) of the channel deformed to provide one ball track turned-in edges (19,20) to the sides of the channel providing the other two tracks, and the inner runner is formed from sheet metal so that the two arms (22,23) are of double thickness in the form of lobes extending outwards beyond the line joining the centres of the respective sets of balls and the angles between the stem and the arms and between the two arms rounded to form tracks for the three sets of balls. A ball slide system according to claim 1, wherein the triangular array is an isosceles triangle, the stem extending outwardly from the base of the triangle. A ball slide system according to claim 1, wherein the triangular array is an equilateral triangle. A ball slide system according to any preceding claim, wherein the balls of the three sets are of the same size. A ball slide system according to any preceding claim, wherein, for double extension, two inner runners are integral with one another and run in respective outer runners of which one is inverted with respect to the other. A ball slide system according to claim 6, wherein the two inner runners are offset with respect to each other.

Inventors: JACKSON, ANDREW CLIVE, JACKSON, PAUL ADRIAN SOUTHON
Applicants: JACKSON, ANDREW CLIVE, JACKSON, PAUL ADRIAN SOUTHON
Application year: 1986
Main classification: A47B88
IPC codes: F16C29, A47B88