GB2177165A

GB2177165A - Bearing cages

Info

Publication number: GB2177165A
Application number: GB08616490A
Authority: GB
Inventors: Brian Anthony Davies
Original assignee: FIRSTEEL METAL PROD
Current assignee: FIRSTEEL METAL PROD
Priority date: 1985-07-06
Filing date: 1986-07-07
Publication date: 1987-01-14
Anticipated expiration: 2006-07-07
Also published as: GB2177165B; GB8616490D0

Abstract

A bearing cage comprises a body having a base portion and a pair of spaced parallel upstanding walls. Ball bearing locations 15 are formed in the walls and each comprises a circular aperture 16 having inner and outer openings 17 and 18. These are sized just below the diameter of the ball bearing so that once a ball bearing is introduced into the aperture it is retained therein. Ball bearings are snap-fitted into these apertures. Apparatus for automatically snap- engaging ball bearings in the locations 15, comprises chutes 25 which deliver ball bearings to a tapering section 27 adjacent a moving bearing cage body. The ball bearings are then urged into respective apertures 16 by the inwardly tapering walls. <IMAGE>

Description

SPECIFICATION Bearing cages This invention relates to bearing cages and in particular, but not exclusively, to bearing cages for use in drawer runners or the like.

Drawer runners have been used for many years in the construction of filing cabinets. In the majority of such runners the balls are laterally retained in the cage by being located between the inner and outer sliding members and so have to be positioned in the locations in the cage as the runner is assembled. Recently a bearing cage has been proposed in which the ball bearings are held within the cage and hence assembly is simplified. However, the use of drawer runners has recently extended to the domestic market and particularly to kitchen units. Here the metallic clangs created by the use of a metal cage are unacceptable and hence a plastics cage has had to be substituted. To date no simple method of retaining ball bearings within the cage has been developed for plastics cages and so the complex and slow hand assembly mentioned above still has to be used.

It is an object of the invention to provide an improved bearing cage and/or an apparatus or method for assembling bearings in a cage.

From one aspect the invention consists in a bearing cage having a ball location for snapfittingly receiving a ball bearing.

In a preferred embodiment the location comprises an aperture in the wall of the cage and one side of the aperture is formed with a flexible lip, for example by means of a channel formed in one side of the wall circumjacent the aperture. In this instance the aperture may be circular and the channel annular.

The internal periphery of the aperture may be cut away so that there is a substantially line contact between the ball bearing and the wall at two spaced apart positions, when the ball bearing is engaged in the location. The diameter of the opening of the aperture may be between 85 and 98 per cent of the diameter of the ball and the aperture may extend through the wall and the other side of the aperture may be rigid relative to the lip. The lip may be cut away at the opening to facilitate entry of the ball.

The cage may have a plurality of locations, which may be arranged in pairs on parallel walls of the cage and the cage may have a body made of plastics material in which the locations are formed.

The invention also includes a drawer runner including a cage as defined above and for the purposes of this specification the term drawer runner" covers devices for slidably supporting baskets or other article supports as well as drawers.

From a further aspect the invention consists in apparatus for snap-fitting a first element in a location in a second element,comprising a channel defining a path of movement for the second element, means for delivering the first element to the channel such that the first element can locate in the location, the channel having a first broad portion into which the first element can be drawn to lie between the second element and the channel wall and a downstream tapering portion in which the wall of the channel is shaped to cam the first element into the location to snap-fittingly engage it therein.

The apparatus may further include delivery means on either side of the channel and the channel may taper on each side. Preferably the delivery means debouche obliquely into the channel. The first element may comprise a ball bearing and the second element may comprise a bearing cage.

From another aspect the invention consists in a method of snap-fitting a ball bearing into a location in a bearing cage,comprising moving the cage along a channel defining a path of movement, delivering the ball bearing to the location in the cage, moving the cage and hence the ball further along the path of movement to trap the ball bearing between a wall of the channel and the cage and moving the cage and ball bearing through a tapering portion of the channel to force the ball into the location.

Although the invention has been defined above, it is to be understood it includes any inventive combination of the features set out above or in the following description. An object of the invention has been stated, but the invention is not limited to articles, apparatus or methods which fulfil that object.

The invention may be performed in various ways, specific embodiments of which will now be described with reference to the accompanying drawings, in which: Figure 1 is a view of a bearing cage from above; Figure 2 is a side view of the cage of Figure 1; Figure 3 is a section along the line AA of Figure 1 and shows a ball bearing location; Figure 4 is a side view along the arrow B of the location of Figure 3; Figure 5 is an end view of the cage of Figure 1, and Figure 8 is a front view of an apparatus for locating ball bearings in a bearing cage.

Referring to Figures 1 to 6, a bearing cage 10 comprises a body, generally indicated at 11, and a plurality of ball bearings 12. The body has a base portion 13 and a pair of spaced parallel upstanding walls 14. Located along the walls, in aligned pairs, in groups of four, are ball-bearing locations 15 in which the ball bearings 12 are received.

The locations 15 are all identical, although those on one wall are oppositely sensed from those on the other wall, i.e. the locations can all be set to face outwardly. Thus, each location 15 comprises a circular aperture 16 having inner and outer openings 17 and 18. The openings 17,18 are sized just below the diameter of the ball bearing 12 so that once a ball bearing is introduced into the aperture 16 it is retained therein. Part of the wall 14 defining the inner opening 17 is essentially rigid, but that defining the outer opening 18 is at least partially flexible because that opening is defined by a lip 19. This lip 19 is itself formed by an annular cutout 20 which surrounds the aperture 16 and penetrates to about half the thickness of the wall 14. The leading or outer edge of the lip 19 is bevelled at outer opening 18 to provide a lead-in for the ball bearings 12.

Thus a ball bearing 12 can be simply engaged in the location 15, by initially disposing it in the outer opening 18 and then pushing the ball into the aperture 18 so that the lip 19 initially flexes into the cutout 20 to allow the ball to pass and then springs back to its original position to grip the ball within the cage 10.

It will be seen that the inner periphery of the aperture 16 is cut away at 22 so that only line contact is made with the ball bearing 12 at each of the openings 17,18.

The method of assembly enabled by this construction is extremely simple and quick even if carried out by hand and the balls are safely retained in the cage prior to the final assembly of the drawer runner so that that latter operation can also be accelerated.

In Figure 6 an apparatus for automatically engaging ball bearings 12 in the locations 15 is shown. This comprises a body 23 which defines a closed mouth channel or passageway 24 along which bodies 11 of the bearing cage 10 can be passed. At its upper end the channel 24 is slightly wider than the body 11, whereas at its lower end it is almost exactly the width of the body 11 with the balls assembled. Intermediate the ends of the channel 24 are two oblique chutes 25 which debouche into the channel 24 just upstream of a wider portion 26 of the channel 24. Downstream of the section 26 is a tapering section 27. In use ball bearings 12 are fed by gravity down each channel 25, whilst bodies 11 are fed down the channel 24 at a relatively steady rate by a piston or other suitable means. As each location 15 passes the mouth 28 of the chutes 25 the leading ball bearing 12 rolls into the opening 18 and is sufficiently engaged therein to be dragged down the channel 24 by the movement of the cage 10. When the ball bearing 12 enters the wider portion 26 of the channel 24, it becomes trapped between the wall of the channel 29 and the body 11, and once trapped it can be steadily urged into the aperture 16 by the tapering walls of the tapering section 27. Thus, merely by passing bodies 11 down the channel 24, automatic snap-fitting engagement of ball bearings in the locations is achieved. It is believed that this arrangement need not merely apply to the assembly step described above, but can also apply to many other snap-fitting assembly operations.

Claims

1. A bearing cage having a ball location for snap-fittingly receiving a ball bearing.

2. A cage as claimed in claim 1, wherein the location comprises an aperture in a wall of the cage and one side of the aperture is formed with a flexible lip.

3. A cage as claimed in claim 2, wherein the lip is formed by a channel formed in the one side of the wall circumjacent the aperture.

4. A cage as claimed in claim 3, wherein the aperture is circular and the channel annular.

5. A cage as claimed in any one of claims 2 to 4, wherein the internal periphery of the aperture is cut away so that there is a substantially line contact between the ball bearing and the wall at two spaced apart positions when the ball bearing is engaged in the location.

6. A cage as claimed in any one of claims 2 to 4, wherein the diameter of the opening of the aperture is between 85 and 98 per cent of the diameter of the ball.

7. A cage as claimed in any one of claims 2 to 6, wherein the aperture extends through the wall and the other side of the aperture is rigid relative to the lip.

8. A cage as claimed in any one of claims 2 to 7, wherein the lip is cut away at the opening to facilitate entry of the ball.

9. A cage as claimed in any one of the preceding claims having a plurality of locations.

10. A cage as claimed in any one of the preceding claims having a body made of plastics material in which the locations are formed.

11. A bearing cage substantially as hereinbefore described with reference to the accompanying drawings.

12. A drawer runner incorporating a cage as claimed in any one of the preceding claims.

13. Apparatus for snap-fitting a first element in a location in a second element comprising a channel defining a path of movement for the second element, means for delivering the first element to the channel such that the first element can locate in the location, the channel having a first broad portion into which the first element can be drawn to lie between the second element and the channel wall and a downstream tapering portion in which the wall of the channel is shaped to cam the first element into the location to snap-fittingly engage it therein.

14. Apparatus as claimed in Claim 13, wherein there are delivery means on either side of the channel and the channel tapering portion on each side of the channel.

15. Apparatus as claimed in Claim 13 or 14, wherein the delivery means debouche obliquely into the channel.

16. Apparatus for snap-fitting a first element in a location in a second element substantially as hereinbefore described with reference to the accompanying drawings.

17. A method of snap-fitting a ball bearing into a location in a bearing cage comprising moving the cage into a channel defining a path of movement, delivering the ball bearing to the location in the cage, moving the cage and hence the ball bearing further along the path of movement to trap the ball bearing between a wall of the channel and the cage and moving the cage and ball bearing through a tapering portion of the channel to force the ball into the location.

18. A method of snap-fitting a ball bearing into a location in a bearing cage substantially as hereinbefore described with reference to the accompanying drawings.