GB2222867A - An idler roller for a belt or roller conveyor - Google Patents

Abstract

A roller (11) for a roller conveyor, formed as an assembly of individually replaceable parts, comprising a cylindrical roller wall member (24), at least one removable roller end member (26, 27) removably connectable thereto, and a central spindle (44) with respect to which the said cylindrical roller wall member (24) and roller end member (26, 27) are rotatable and which defines the axis of rotation of the roller and projects from the ends thereof to permit mounting of the roller on a fixed support. <IMAGE>

Description

AN IDLER ROLLER FOR A BELT OR ROLLER CONVEYOR The present invention relates to an improved idler roller for a belt conveyor.

Belt conveyors comprise a plurality of cylindrical idler rollers arranged on fixed axes to form an array lying generally in a plane defining the conveyor surface by the upper generatrices of the plurality of rollers. Belt conveyors are used to carry bulk material via a flexible belt running on sets of idler rollers spaced at intervals to support the weight of the belt and material being carried. The rollers turn freely on their axes as the belt passes over them. Roller conveyors comprise an array of rollers on parallel axes which support articles to be conveyed thereby on successive roller crests which define an effective support plane.

Although the rollers share the load of the articles or material carried and conveyed thereby they are nevertheless subject to wear both on the cylindrical surface of the roller and on their bearings, and it is also possible for occasional accidents to cause damage to the cylindrical roller surface making it unusable.

Prior art rollers are producing having cylindrical walls generally made of metal and in come cases coated with a wear resistant or low friction material, with the cylindrical walls being secured permanently to end walls, for example by welding, in which end walls the bearings for the roller are secured, again usually in a fixed and non-removable manner such as by welding. The techniques used for the manufacture of such rollers have been employed in order to ensure strict alignment between the axis of the cylindrical roller surface and the axis of rotation defined by the bearings in the opposite end walls, and also to ensure that this strict parallelism is retained in use despite the rigorous conditions which the roller may experience. As a result of this any roller which becomes worn or damaged requires total replacement.

In industrial locations or in mines, for example, this can result in considerable expense much of which is wasted if the roller damage or wear is localised. For example, the roller bearings may wear out leaving the roller imperfectly supported for rotation about its axis whilst the cylindrical wall of the roller may nevertheless be perfectly serviceable. Likewise, any accidental impact on the cylindrical roller surface may cause damage to this making the roller unusable but the roller may-include perfectly serviceable bearing having considerable life expectancy which, however, cannot be realised due to the fixed connection of the bearings to the damaged roller.

The present invention seeks, therefore, to provide a roller suitable for roller bearings in which this disadvantage is overcome by forming the roller as an assembly of parts all of which are easily and individually replaceable.

According to one aspect of the present invention, therefore, a roller for a belt or roller conveyor is formed as an assembly of individually replaceable parts, comprising a cylindrical wall member, at least one radially extending planar end wall member removably connectable thereto, and removably mounted bearings for rotatably carrying the said cylindrical wall member for rotation about its axis.

According to another aspect of the present invention, there is provided a roller for a roller conveyor formed as an assembly of individually replaceable parts, comprising a cylindrical roller wall member, at least one removable roller end member removably connectable thereto, and a central spindle with respect to which the said cylindrical roller wall and roller end member are rotatable and which defines the axis of rotation of the roller and projects from the ends thereof to permit mounting of the roller on a fixed support.

In one embodiment of the present invention only one end member of the roller is removable, the other end member being fixed permanently to or formed integrally with the cylindrical surface of the roller. However, in accordance with the principles of the present invention, it is preferred that both end wall members are removable from the cylindrical wall member in order that as many parts as possible are individually replaceable. In either embodiment both bearings are individually replaceable, one bearing being removable from the fixed end wall and the other bearing being removable from the removable end wall.

In a preferred embodiment of the invention the said cylindrical wall member comprises an outer cylindrical skin layer of wear resistant material attached or otherwise bonded to an inner reinforcing liner. The reinforcing liner and skin layer are preferably bonded together to form a single unit which is open at both ends and conveniently the reinforcing member may be axially shorter than the skin layer so as to form a radially inwardly directed rebate or annular shoulder the purpose of which will be described in more detail below.

In an embodiment in which the said inner reinforcing liner and the said outer skin layer together form an annular radially inner shoulder at least at the said one end, it is preferred that the said end wall member has a cooperating annular radially outer shoulder engageable against the said radially inner shoulder to locate the said end wall member in position. In embodiments in which both end walls are removable it is, of course, symmetrical in that two annular shoulders are formed one at each end of the cylindrical wall member and the end wall members may be identical with one another.

The or each said end wall member preferably has a central opening the rim of which is formed as an annular shoulder for receiving and locating a bearing. Bearings of any known type may be employed although it is preferred for the bearings to be rolling element bearings as these have a long service life and low frictional properties.

The bearings may be carried on a spindle having means for determining the axial separation of the bearings and for retaining them fixed in position spaced a predetermined distance from one another. The separation-determining means preferably comprise a radially outwardly extending annular shoulder projecting from the said spindle against which a bearing support member engages.

In embodiments in which the bearings are rolling element bearings it is preferred that the dimensions of the bearing supports are such that the bearings themselves are an interference or press fit thereon. Likewise, it is preferred that the bearing dimensions are chosen such that each bearing is an interference or force fit within the central opening in the associated end wall.

Preferably, the said bearing-separation determining means comprise a collar fixed to the spindle to determine the axial position of at least one bearing support, the other bearing support being either permanently secured to the spindle or adjustable thereon in the same manner. The said collar may, conveniently, be formed as an internally threaded element for engagement on a correspondingly threaded portion of the spindle whereby to provide for simple adjustment of the axial position and ready retention of the selected adjusted position until the collar is secured in position on the spindle. Such securement may be achieved by welding the collar to the spindle or by bringing a lock nut or other friction fixing into engagement with it.

Each end wall preferably has an associated external cover member having a central aperture to receive and fit onto the bearing support member at that end of the roller.

Like the separation-determining means, at least one of the bearing support members may be threadedly engaged on a threaded section of the said spindle and held in a selected position thereon by appropriate means such as a lock nut or thread deformation.

Two embodiments of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a roller assembly incorporating three rollers formed as embodiments of the present invention; Figure 2 is a section taken on the line II-II of Figure 1 illustrating one of the rollers in the assembly of Figure 1 in more detail; and Figure 3 is an axial sectional view of a second embodiment of the invention.

Referring first to Figure 1 the roller assembly shown comprises three cylindrical rollers 11, 12, 13 mounted on a support rack 14 in such a way that the end rollers 11, 13 of the array are held with their axes inclined at a shallow angle to the horizontal so that the ends of the outer cylinders are raised slightly so as to exert a self-locating action on the conveyor belt running over a series of arrays such as that illustrated in Figure 1.

The roller 11 is provided with axial projections such as the projection 21 which is the only one visible in Figure 1, carried on terminal brackets 15, 16 one at each end of the roller 11. Likewise, the roller 12 is mounted on respective terminal brackets 17, 18 and the roller 13 is mounted on respective terminal brackets 19, 20 of the support 14. All of the terminal brackets are formed, as the bracket 15, with a bifurcated end having two fingers 22, 23 defining a slot 10 for receiving the axial projection 21 of the roller 11.

Referring now to Figure 2, the roller 11 comprises a cylindrical outer layer 24 of wear resistant resilient material such as polyurethane shaped as a right circular cylinder with open ends.

On the radially inner cylindrical surface of the outer skin layer 24 is bonded a similar right-circular reinforcing member 25 conveniently made of steel. The axial length of the reinforcing member 25 is slightly less than that of the skin layer 24 so as to form an annular rebate or shoulder defined by the axial ends of the reinforcing member 25 and identified with the reference numeral 33 at the right hand end and the reference numeral 37 at the left hand end.

Fitted into the open ends of the cylinder defined by the skin 24 and the reinforcing member 25 are respective end walls 26, 27 formed as discs with respective radial flange portions 34, 36 which engage against the end faces 33, 37 respectively of the reinforcing member 25. The end wall member 27 is formed as a flat disc with a central aperture 28 from which projects an inward radial flange 29 forming an annular shoulder against which engages a rolling element bearing 30 housed within the aperture 28. The relative dimensions of the aperture 28 and the roller element bearing 30 are such that the latter is a force fit within the aperture so as to be securely fixed to the end wall member 27 and located axially with respect thereto by contact against the annular shoulder 29.The rolling element bearing 30 is carried on a bearing support member 31 formed as a collar securely fixed to a spindle 44 and welded thereto by the welding bead 32. A nut 21, which constitutes the axial projection from the roller 11 for supporting the roller on the bifurcated bracket 15 as illustrated in Figure 1, is screwed to the end of the spindle 44.

At the other end of the roller 11 the end wall member 35 which is identical in shape to the end wall member 27 has an aperture 39 with a radial inward flange 38 defining an annular shoulder 40 against which engages a rolling element bearing 41 which, again is a press fit in the aperture 39 such that the bearing 41 is securely located within the end wall member 35 by its contact with the annular shoulder 40. The bearing 41 is carried on a bearing support member 42 formed as a collar threadedly engaged on a threaded portion 43 of the spindle 44 (which in practice may be threaded throughout its length as illustrated in Figure 2) and engaged against a locating collar 45 formed in this embodiment as a nut threaded onto the spindle 44, adjusted in position and welded thereto by a welding bead 46.The threaded collar 42 is held securely in position against the locating member 45 by a lock nut 47 which serves the same purpose as the lock nut 21 at the other end of the spindle 44. The axial separation of the bearings 30, 41 is thus determined by the positions on the spindle of the bearing support members 31 and 42 which, in turn, are determined by the position of the locating member 45.The rolling element bearings 30, 41 are a press fit on the bearing support members 31, 42 so that, once in position, the spindle 44, the bearings 30, 41 and the end walls 27, 35 are all securely located with respect to one another and this sub-assembly is located with respect to the cylindrical wall of the roller 11 by engagement of the radial flanges 34, 36 of the end wall members 27, 35 against the axial ends 33, 37 of the reinforcing member 25 whilst the end wall members 27, 35 are axially inwardly located from the ends of the surface layer 24.

The annular recess formed thereby is filled by a cover plate 48 over the end wall member 35 and 50 over the end wall member 27: the cover plates 48, 50 have respective axial bosses 49, 51 which are an interference fit on the bearing support members 30, 42 respectively so that the end walls 27, 35 and the cylindrical wall composed of the reinforcing member 25 and the surface layer 24 can rotate with respect thereto.

It will be appreciated from the above description that an accident involving any member of the roller 11 described hereinabove will not result in the necessity for the entire roller to be discarded since any damaged member can be replaced simply by unscrewing the end nuts 21 or 47, unscrewing the bearing support member 42, withdrawing the spindle 44 and separating the end walls 27, 35 from the cylindrical wall of the roller 11. This can be achieved readily using only spanners matching the dimensions of the nuts 21, 47 without requiring any other tools except a press tool for withdrawing the bearings from the end walls.

A suitable material for the end walls 27, 35 is a hard polyurethane similar to that of the skin layer 24 which has a considerable elasticity allowing the bearings 30, 41 to be securely held therein without requiring a great force to be exerted for insertion or removal. Likewise, the end covers 50, 48 may also be made of the same polyurethane material to provide a wear resistant and impact absorbing external surface to the roller.

Referring now to Figure 3, an alternative embodiment is shown. The roller shown in Figure 3 comprises a cylindrical roller wall member 52 reinforced internally by a coil spring 53. At its ends the cylindrical roller wall member 52 is closed by respective opposite roller end members 54, 55 which are identical to one another and of which only the end member 54 will be described in detail hereinafter. The end member 54 is integrally formed from polyurethane, like the cylindrical roller wall member 52, and comprises a radially inner radial end wall portion 55, a radially outer radial wall portion 56 joined to the radially inner radial wall portion 55 by conical wall portion 57.

Centrally within the inner radial wall portion 55 is located an axially extending boss 58 which forms a plane bearing with a roller spindle 59 which passes centrally through the roller, which is generally indicated with the reference numeral 60. The radially outer perimeter of the outer radial wall portion 56 has the same diameter as that of the cylindrical roller wall portion 52 and is formed with a curved edge region 61 at its outer end face.

Projecting axially from the inner face of the radially outer radial wall portion 56 is an axial skirt portion 62 having an helical groove 63 formed in its radially outer surface for receiving the last two turns of the coil spring 53. At the junction between the axial skirt portion 62 and the radially outer radial wall portion 56 there is defined an annular shoulder 64 against which the cylindrical roller wall portion 52 engages when the roller end member 54 is fitted in position as illustrated in Figure 3, in which position it is retained by the tension on the coil spring 53.Indeed, fitting of the roller end member 54 is achieved by drawing out the free end of the coil spring 53 and screwing the axial skirt 62 onto the end two turns of the coil spring before releasing the roller end member 54 to be drawn by the tension in the spring 53 to engage the annular shoulder 64 against the end 65 of the cylindrical roller wall member 52.

The spindle 59 is retained in position by a pair of collars, only one of which is illustrated in Figure 3, and identified with the reference numeral 65, which are fitted over the spindle 59 and clamped in position by circumferential clamps, commonly termed hose clamps, and identified in Figure 3 with the reference numeral 66.

The advantages of the roller structure described in relation to Figure 3 are the light weight, ease of assembly and the fact that any component can be removed and replaced without the need for any tools, apart from a tool required to slacken or tighten the hose clamp 66 (conventionally a screwdriver).

The coil spring 53 serves the double purpose of reinforcing the polyurethane cylindrical roller wall 52 and retaining the roller end members 54, 55. The spindle 59, unlike the embodiment of Figure 2, requires no threading to receive nuts, although a prismatic end 66 may be formed, conveniently by screw threading the very end portion to receive a nut, to ensure that the spindle 59 is held in the mounts non-rotatably.

Claims (25)

1. A roller for a roller conveyor formed as an assembly of individually replaceable parts, comprising a cylindrical roller wall member, at least one removable roller end member removably connectable thereto, and a central spindle with respect to which the said cylindrical roller wall and roller end member are rotatable and which defines the axis of rotation of the roller and projects from the ends thereof to permit mounting of the roller on a fixed support.

2. A roller as claimed in Claim 1, in which the said removable roller end member is resiliently urged into position on the cylindrical roller wall member.

3. A roller as claimed in Claim 1 or Claim 2, in which the said removable roller end member is located on the spindle by a spindle abutment stop thereon which limits the relative axial movement between the spindle and the said removable roller end member.

4. A roller as claimed in Claim 3, in which the said spindle abutment stop is formed as a collar clamped in a selected position on the spindle.

5. A roller as claimed in any of Claims 2 to 4, in which the resilient bias urging the roller end member into position is applied thereto by a roller cylindrical wall reinforcement member.

6. A roller as claimed in Claim 5, in which the roller cylindrical wall reinforcement member is a helical spring held under tension between opposite roller ends within the roller body.

7. A roller as claimed in Claim 6, in which the said helical spring is a metal coil spring.

8. A roller as claimed in Claim 6 or Claim 7, in which the said removable roller end member has an axial skirt portion engageable within an open end of the cylindrical roller wall member, the said axial skirt portion having a radially outer circumferential groove for receiving at least one turn of the said helical spring whereby to interengage this and the said removable roller end member so as to apply to the latter an axial force generated by placing the said helical spring under tension.

9. A roller as claimed in Claim 8, in which the said axial skirt projects axially from a radial wall of the said roller end member which latter has a peripheral lip defining, with the said axial skirt, an annular shoulder for receiving an end of the said cylindrical roller wall member.

10. A roller as claimed in any preceding Claim, in which the said removable roller end member has a central axially extending boss with a central aperture through which the said roller spindle extends, the said axial boss forming a plain bearing for rotation of the said removable roller end member with respect to the said spindle.

11. A roller as claimed in any preceding Claim, in which there is a removable roller end member at each end of the roller body defined by the cylindrical roller wall member.

12. A roller for a roller conveyor, as claimed in Claim 1, formed as an assembly of individually replaceable parts, comprising the said cylindrical roller wall member, at least one radially extending roller end member removably connectable thereto, and removably mounted bearings for rotatably carrying the said cylindrical wall member for rotation about its axis with respect to the said central spindle.

13. A roller as claimed in Claim 12, in which the said cylindrical wall member comprises an outer cylindrical skin layer of wear resistant material supported by an inner reinforcing member.

14. A roller as claimed in Claim 13, in which the said inner reinforcing member is a liner and the said outer skin layer form an annular radially inner shoulder of the said one end and the end wall member has a cooperating annular radially outer shoulder engageable against the said radially inner shoulder to locate the said end wall member in position.

15. A roller as claimed in any of Claims 12 to 14, in which the said cylindrical wall member is open at both ends thereof and there are provided two flat end wall members receivable in respective ends thereof.

16. A roller as claimed in any of Claims 12 to 15, in which the or each said end wall member has a central opening the rim of which is formed as an annular shoulder for receiving and locating a bearing.

17. A roller as claimed in any of Claims 12 to 16, in which the bearings are carried on a spindle having means for determining the axial separation of the bearings and for retaining them fixed in position spaced a predetermined distance from one another.

18. A roller as claimed in Claim 17, in which the separation determining means comprise a radially outwardly extending annular shoulder projecting from the said spindle against which engages a bearing support member.

19. A roller as claimed in Claim 18, in which the bearings are rolling element bearings and the dimensions of the bearing supports are such that the bearings are an interference fit thereon.

20. A roller as claimed in Claim 18 or Claim 19, in which the bearing dimensions are such that each bearing is an interference fit within the central opening in the associated end wall.

21. A roller as claimed in any of Claims 18, 19 or 20, in which the said bearing separation determining means comprise a collar fixed to the spindle to determine the axial position of the bearing support.

22. A roller as claimed in Claim 21, in which the collar is internally threaded for engagement on a correspondingly threaded portion of the spindle whereby to adjust the axial position thereof.

23. A roller as claimed in any of Claims 12 to 22, in which each end wall has an associated external cover member having a central aperture to receive and fit on the bearing support member at that end of the roller.

24. A roller as claimed in any of Claims 19 to 23, in which at least one of the bearing support members is threadedly engaged on a threaded section of the said spindle and held in a selected position by lock nut means.

25. A roller formed as an assembly of replaceable parts substantially as hereinbefore described with reference to, and as shown in Figures 1 and 2 or Figure 3, of the accompanying drawings.