GB2233620A

GB2233620A - Roller conveyor

Info

Publication number: GB2233620A
Application number: GB8914155A
Authority: GB
Inventors: Michael Anthony James; Paul Francis Craddock; John Brian Newman
Original assignee: EXCEL AUTOMATION Ltd
Current assignee: EXCEL AUTOMATION Ltd
Priority date: 1989-06-20
Filing date: 1989-06-20
Publication date: 1991-01-16
Anticipated expiration: 2009-06-20
Also published as: GB2233620B; GB8914155D0

Abstract

A roller conveyor e.g. an accumulation conveyor (10) where articles transported by the conveyor can accumulate, comprises a plurality of rollers (16) which together provide a conveying surface, the rollers (16) each being rotatable about their longitudinal axis (B) with at least one of the rollers (16) being driven by a drive means comprising a motive means (17) and a transmission (18, 19), the driven roller (16) carrying a drive member (20) which is driven via the transmission (18, 19) and there being a friction means (36) whereby drive is transmitted from the respective drive member (20) to the roller (16), the friction means comprising a spring means (41) which exerts its spring force in a direction parallel to or coincident with the axis of rotation (B) of the roller (16) to urge the drive member (20) into frictional engagement with a friction surface (33) of the roller (16), so that when articles are accumulated on the conveyor (10), the friction means can slip to allow the drive member (20) to be driven by the transmission (18, 19) whilst the roller (16) remains stationary, when the spring force providing the frictional engagement between the drive member (20) and the frictional surface (33) is overcome. <IMAGE>

Description

Title: Roller Conveyor Description of Invention This invention relates to a roller conveyor and more particularly, but not exclusively, to an accummulation conveyor where articles transported by the conveyor can accumulate.

When such accummulation occurs, it is preferred for any driven rollers to be stopped from rotating.

According to one aspect of the invention we provide a conveyor providing a plurality of rollers which together provide a conveying surface, the rollers each being rotatable about their longitudinal axis with at least one of the rollers being driven by a drive means comprising a motive means and a transmission, the driven roller carrying a drive member which is driven via the transmission, and there being a friction means whereby drive is transmitted from the respective drive member to the roller, the friction means comprising a spring means which exerts its spring force in a direction parallel to or coincident with the axis of rotation of the roller to urge the drive member into frictional engagement with a friction surface of the roller.

Thus when articles are accummulated on the conveyor, the friction means can slip to allow the drive member to be driven by the transmission whilst the roller remains stationary, when the spring force providing the frictional engagement between the drive member and the frictioncl surface is overcome.

In one embodiment, the friction driven roller comprises a spindle which extends laterally of the direction in which articles are conveyed, and a roller casing carried on the spindle and held fast relative to the spindle. The ends of the spindle may project from either end of the roller casing and be received in bearings of the conveyor to ease rotation.

The friction surface may comprise a flange carried by the spindle and preferably rigidly mounted thereon, and the drive member mav also carry a friction surface, provided for example by a bush which encbies the drive member to rotate relative to the spindle.

The bush may include a reduced diameter hub part which is received in a central opening of the drive member.

Thus frictional engagement between the drive member and the flange may provide a friction drive.

The spring means may bear directly on the drive member although preferably bears on a washer or friction plate which is fixed relative to the spring, but allows the drive member to rotate relative to the spring means.

Preferably the bush is made from a suitably lubricated material such as Oilite which readily allows relative rotation when slippage occurs.

The spring means may comprise one or more coil springs, Belleville washers or any other suitable spring means to exert a spring force in the friction means.

The force exerted by the spring means may be adjustable. For example the spring means may bear on a nut threaded onto the spindle, the position of the nut being adjustable along the spindle to adjust the spring force.

The drive transmission may comprise a continuous loop such as a chain or belt driven by an output member of the motive means. Where the loop is a chain, the drive member may comprise a sprocket.

The invention will now be described with the aid of the accompanying drawings in which: FIGURE I is a perspective view of a conveyor in accordance with the invention.

FIGURE 2 is a side section of part of the convevor of Figure 1.

Referring first to figure 1, conveyor 10 comprises a frame II having sides 12,13, and ends 14,15, and is adapted to be used in conjunction with other conveyors to conveyor articles in a conveying direction indicated bv arrow A.

A conveying surface for the articles is provided by a plurality of rollers ló, all of which are driven in this example, although in another example some may not be driven.

Drive is transmitted from a motive means comprising an electric motor 17 mounted beneath the conveying surface, via an ouput member comprising a sprocket 18 to a loop comprising a chain 19. Chain 19 engages with drive mernbers 20 which transmit the drive to the rollers 16, the chain 19 hcving a top run 21 and a return run 22, and guides 23 to guide the chain 19.

Referring now also to figure 2, each of the rollers 16 comprises a spindle 25 and a roller casing 26 secured relative thereto by end bungs 27.

The roller spindle 25 is hexagaonal in section along a majority of its length to facilitate keying the spindle 25 to the bungs 27. The ends of the spindle 25 are indicated at 29 and 30, and project from the roller casing 26.

One end 29 of the spindle 25 is received by a bearing assembly 31 which in use is mounted by the side 13 of the frame II, which is not shown in figure 2. The opposite end 30 of the spindle 25 is received in a further bearing assembly 32 which is mounted by side 12 of the frame 11, the bearing assemblies 31,32, together permitting a free rotation of the spindle 25 in the frame.

The end 30 of spindle 25 beyond the bearing assembly 32 is round in section and carries a flange 33 which provides a friction surface, and is fixed relative to the spindle 25. Adjacent the flange 33 the drive member 20 is received on the end 30 of the spindle 25, the drive member 20 including a sprocket 34 to engage with the chain 19, and a bush 35 which includes a friction surface 36 which frictionally engages the flange 33, and a reduced diameter hub part 37 which is received in a central opening 38 of the sprocket 34. The sprocket 34 and bush 35 are held rigidly together by pins 40.

A spring means 41 is received on the end 30 of the spindle 25 and exerts a force between the drive member 20 and a stop comprising a nut 42 received on a threaded outward end part 43 of the spindle 25.

The spring means 41 comprises a coil spring in this example which carries a washer 44 which engages the drive member 20, and a washer 45 on the opposite end which engages the nut 42. In another example, instecd of a coil spring, the spring means 41 couid comprise Belleville washers or any other suitable spring means preferably which exerts a force in a direction parallel to or coincident with the axis of rotation indicated at B, of the roller 16.

The drive member 20 is able to rotate relative to the spindle 25 by virtue of the bush 35, but by virtue of the spring means 41 urging the drive member 20 to the left as seen in figure 2, the flange 33 and friction surface 36 will engage and so normally drive will be transmitted from the drive member 20 to the roller 16.

However, in the event that articles accummulate on the convevina surface of the conveyor 10, the frictional force between the roller ló and the article will be sufficient to overcome the force of the spring 4 and thus slippage will occur between the frictional surfaces of the flange 33 and the bush 35. Thus the drive transmission can continue to operate to drive those rollers where the article is not accummulated, but drive to the or each of the rollers 16 where the article is accummulated will be discontinued.

Immediately the article is able to move in the direction of arrow A again, or if the article is removed from the conveying surface, drive is again transmitted from the drive member 20 to the roller 16 by virtue of the frictional contact between the surfaces of the flange 33 and bush 35.

In the present example, the bush 35 and washer 44 are made from a suitably lubricated material such as Oilite so that the surfaces can freely rotate relative to one another.

It will be appreciated that by virtue of the nut 42 being received on the threaded outward end part 43 of the spindle 25, the force exerted by the spring 41 can be adjusted by rotating the nut 42 to move the nut longitudinally of the spindle 25.

The strength of the spring 41, and its adjustment by nut 42, can be selected depending upon the weight and size of articles being transported, the diameters of the roller 16 and any other factors, to achieve a suitable friction drive which will readily permit slippage in the event that articles become accummulated on the conveyor 10.

Various further modifications are possible without departing from the scope of the invention. For example, it is not essential for the spindle 25 to be hexagonal along the majority of its length, but if desired, the bungs 27 could be otherwise keyed to a round section spindle 25.

Instead of the transmission from the motor 17 to the drive members being by way of a chain 19, drive may be transmitted by way of a belt, the drive members 20 each having a pulley wheel instead of a sprocket, and the sprocket 18 of the motive means comprising a pulley wheel.

The features disclosed in the foregoing description or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, cs appropriate, may, separately or in any combinction of such features, be utilised for realising the invention in diverse forms thereof.

Claims

I. A conveyor providing a plurality of rollers which together provide a conveying surface, the rollers each being rotatable about their longitudinal axis with at least one of the rollers being driven by a drive means comprising a motive means and a transmission, the driven roller carrying a drive member which is driven via the transmission, and there being a friction means whereby drive is transmitted from the respective drive member to the roller, the friction means comprising a spring means which exerts its spring force in a direction parallel to or coincident with the axis of rotation of the roller to urge the drive member into frictional engagement with a friction surface of the roller.
2. A conveyor according to claim I wherein the friction driven roller comprises a spindle which extends laterally of the direction in which articles are conveyed, and a roller casing carried on the spindle and held fast relative to the spindle.
3. A conveyor according to claim 2 wherein the ends of the spindle project from either end of the roller casing are received in bearings of the conveyor to ease rotation.
4. A conveyor according to claim 2 or claim 3 wherein the friction surface comprises a flange carried by the spindle friction surface.
5. A conveyor according to claim 4 wherein the flange is rigidly mounted on the spindle.
6. A conveyor according to claim 4 or claim 5 wherein the drive member also carries a friction surface.
7. A conveyor according to claim 6 wherein the friction surface of the drive member is provided by a bush which enables the drive member to rotate relative to the spindle.
8. A conveyor according to claim 7 wherein the bush includes a reduced diameter hub part which is received in a central opening of the drive member.
9. A conveyor according to claim 7 or claim 8 wherein the bush is made from lubicated material which readily allows relative rotation when slippage occurs.
10. A conveyor according to any one of the preceding claims wherein the spring means bears directly on the drive member or bears on a weasher or friction plate which is fixed relative to the spring, but allows the drive member to rotate relative to the spring means.
II. A conveyor according to any one of the preceding claims wherein the spring means comprise one or more coil springs.
12. A conveyor according to any one of the preceding claims wherein the force exerted by the spring means is adjustable.
13. A conveyor according to claim 12 where appendent to claim 2 wherein the spring means bears on a nut threaded onto the spindle, the position of the nut being adjustable along the spindle to adjust the spring force.
14. A conveyor according to any one of the preceding claims wherein the drive transmission comprises a continuous loop such as a chain or belt driven by an output member of the motive means.
15. A conveyor according to claim 14 wherein where the loop is a chain, the drive member comprises a sprocket.
16. A conveyor substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
17. Any novel feature or novel combination of features disclosed herein and/or shown in the accompanying drawings.