The invention relates to an idler roller assembly primarily for use in supporting conveyor belting. BACKGROUND TO THE INVENTION

Idler rollers are in wide general use and there are many designs of these products. There are ongoing developments to obtain better rollers and improved cost effectiveness. While these rollers are driven to rotate by movements of the belt with which they are used the power consumed in rotating the rollers is becoming a serious consideration. Particularly the power concerned in breakout of the rollers from the stationary condition in conveyors of considerable length is a matter of concern along with roller life and costs of repair and replacement. OBJECT OF THE INVENTION

It is the object of this invention to provide an idler roller assembly which provides overall cost advantages over those presently available.

SUMMARY OF THE INVENTION

According to this invention a roller assembly comprises a bearing housing having a shaft bearing outer race seat, an inner seal component having a resilient part for clip-in engagement in the housing to retain a shaft bearing by engagement with the outer end of outer bearing race and an end cap for the housing providing the outer seal component.

The invention also comprises a bearing housing and a bearing with an end cap which forms a mounting socket for a roller shaft and provides a clip-on end to engage the bearing inner race.

Further features of this invention provide for the end cap to have an extension with flat surfaces arranged to engage in an idler roller support cradle, for the inner seal component to conform with the end cap to provide axial and radial sealing for the roller shaft bearing and for the outer surface of the mounting to provide a seat for the end for a roller drum.

The invention further provides for the clip-on end to the mounting socket to be formed as a series of flexible longitudinally extending fingers projecting from the end of the socket mounting and terminating at their free ends in catches to engage the inner end of the bearing inner race and for an outwardly extending peripheral shoulder on the socket adapted to engage the outer end of the inner race. It is another feature of this invention that the inner and outer components of the bearing seal provide co-operating surfaces which extend at about 45 degrees to the axis of the bearing. BRIEF DESCRIPTION OF THE DRAWING

These and other features of this invention will become apparent from the following description of one embodiment in which reference is made to the accompanying drawing:-

Fig 1 shows a cross-section through an idler roller bearing assembly.

DETAILED DESCRIPTION OF THE INVENTION The bearing assembly (1 ) illustrated consists of a moulded housing (2) of suitable plastics material. The outer surface (3) provides a seat for the end of a hollow cylindrical metal, usually steel, drum (4).

The inner surface of the housing (2) provides a seat (5) for the outer race (6) of the bearing (7). The bearing (7) is of larger than conventional size. In particular larger than conventional balls are used in the bearing.

The body of the housing (2) is hollowed out at (8) to keep the overall weight of the product as low as possible while providing adequate support strength.

To retain the bearing (7) on the seat (5) one component (9) of a rotary seal is provided which has at least a peripheral part (10) made as a resilient clip-in engagement in the housing (2). This component (9) is accurately moulded, as is the seat (5), so that the bearing (7) is located in the correct position to provide free running of the inner (21 ) and outer (6) races of the bearing (7). The seal, housing and seat (5) thus form a secure and accurately dimensioned bed for the three sides of the outer race (6) and bearing (7).

An end cap (1 1 ) is formed to have a flange (1 1 A) extending radially to the periphery of the housing (2). The flange (1 1 A) has inwardly directed formations (12) co-operating with mating formations (13) on the component (9) to provide radial sealing between rotary housing (2) and stationary end cap (1 1 ). The mating formations have surfaces which extend at approximately 45 degrees to the bearing axis.

The end cap (1 1 ) has an axial inwardly extending and outward projecting socket (14). This socket (14) serves the function of co-operating with the side (15) of component (9) to provide axial sealing between the end cap and housing (2). The side (15) may have a labyrinth-type (15A) surface with only a small clearance between it and the outer surfaces of the outer wall of the socket (14).

This sealing arrangement protects the bearing (7) against the ingress dirt and moisture. To further protect the bearing (7) a thin lip seal (not shown) may be positioned between the periphery of the end cap (1 1 ) and a rib (22) extending from the edge of the housing (2). A further impregnated lip seal (16) can be provided between the parts (9) and (12) of the bearing seal. The end of the roller shaft indicated by (17) is supported in the socket (14). The outwardly extending part (18) of the socket has flats (23) formed to enable the bearing housing to be mounted on the conventional idler roller cradle (not shown).

The open end of the socket (14) has a circumferentially extending series of spaced longitudinally extending flexible fingers (1 9) with catches (20) on their free ends. These fingers (19) are flexibly resilient so that on assembly they will grip the inner race (21 ) of the bearing (7). With the shaft (17) then inserted into the socket (14) the finger cannot be flexed to release the inner race (21 ). It will be appreciated that with accurate moulding the end of the socket (14) from which the fingers (19) project, the fingers themselves and the catches (20) also hold the bearing (7) securely in position and the assembly of the roller can be maintained to be free running. This has been shown to give a breakout force of as low as 20 grams.

The outer surface of the housing (2) extending from the bottom of the lip (22) is provided with a shallow peripheral groove (24). In the assembly of the roller the end of the roller drum (4) is swaged into groove (24) giving a secure maintenance free mounting of the roller housing (2) in the drum (4).

It will also be understood that the machining of components is kept to a minimum with no skilled labour required to assemble the components into a complete roller.