GB2292362A

GB2292362A - Elevating conveyor

Info

Publication number: GB2292362A
Application number: GB9516869A
Authority: GB
Inventors: Timothy Raymond Hogan
Original assignee: TODD KEITH FRANKLYN
Current assignee: TODD KEITH FRANKLYN
Priority date: 1994-08-19
Filing date: 1995-08-17
Publication date: 1996-02-21
Anticipated expiration: 2015-08-17
Also published as: GB9416811D0; GB2292362B; GB9516869D0

Abstract

A conveyor (1) is provided for conveying articles through an angle of 30 DEG or more with respect to the horizontal and in particular for the conveying of articles vertically. The conveyor (1) comprises a conveyor belt (8) which is mounted so that its load-bearing surface is springy and resilient and is adapted to engage frictionally an article to be conveyed. At least one guide rail (9) is located parallel to the inclined and/or vertical load-bearing surfaces of the conveyor belt (8). The spacing H between the guide rail (9) and the surface of the belt (8) when not distorted is at least substantially comparable to the height of the article to be conveyed above the load-bearing surface of the conveyor belt (8). The article is thereby supported by the guide rail (9) against the belt (8) in use so as to be frictionally gripped by the belt (8) for movement therewith. The load-bearing surface of the conveyor belt (8) may be twisted as it ascends or descends. This is preferably achieved by twisting runners (10) supporting the conveyor belt (8) around one another in the manner of a double helix. <IMAGE>

Description

A CONVEYOR The present invention relates to a conveyor for elevating and lowering articles and in particular relates to a vertical conveyor.

Conventionally, articles to be conveyed vertically upwards or downwards, or through steep inclines and declines are supported on a conveyor belt either by means of flights which project from the belt itself and support the article from beneath as it is conveyed or by a pair of grip chains which are located at the sides of the conveyor belt and grip the sides of the article immediately prior to and during the ascent or descent of the conveyor.

However, the first of these methods is not suitable for articles with dimensions which render them unstable if only supported by a small flight, for example long and floppy articles. Similarly, the second method is also unsuitable for these articles and those which are delicate as the grip chains must clamp the article to be conveyed firmly. Typically, the former method is used for small packaged articles and latter method is used for strong rigid articles such as bottles and cans. However, there is no suitable method for transporting long, floppy and delicate articles such as packets of biscuits and similar foodstuffs and confectionery. Similarly, the transportation of small metal components is also difficult.

It is an object of the present invention to provide a conveyor which will convey, inter alia, such articles both vertically upwards and vertically downwards or through steep inclines and declines in a safe manner.

According to the present invention there is provided a conveyor for conveying articles through an angle of 30 or more with respect to the horizontal comprising a conveyor belt mounted so that its load-bearing surface is springy and resilient and is adapted to engage frictionally an article to be conveyed, and at least one guide rail located parallel to the inclined and/or vertical load-bearing surfaces of the conveyor belt, the spacing between the guide rail and the surface of the belt when not distorted being at least substantially comparable to the height of the article to be conveyed above the load-bearing surface of the conveyor whereby in use the article is supported by the guide rail against the belt so as to be frictionally gripped by the belt for movement therewith.

Preferably, that portion of the guide rail facing the load bearing surface of the conveyor belt comprises a smooth plastics surface with a low coefficient of friction.

In this way, the guide rail does not exert unnecessary drag on the articles being conveyed as they are raised or lowered in height by the belt.

Alternatively, the guide rail comprises a brush strip comprising a plurality of bristles which project towards the load-bearing surface of the conveyor belt to clamp said article momentarily between the guide rail and the belt.

Preferably also, said bristles are angled in a direction pointing towards the direction of travel of the load-bearing surface of the belt.

The guide rail is preferably located substantially centrally of the belt. Alternatively, a pair of parallel guide rails is provided, the rails being equidistantly spaced on either side of the mid-line of the belt.

Preferably also, the conveyor belt is supported at its edges in runners and comprises a series of links which are hinged together by means of resiliently flexible rods.

Advantageously, the rods comprise extruded lengths of a resilient plastics material.

Preferably also, the central portion of the conveyor belt is made of flexible elastomeric links with a roughened load-bearing surface to provide grip. Typically, these links have a dimpled load-bearing surface.

Preferably also, the runners supporting the conveyor belt comprise channels in which opposed edges of the conveyor belt are located, the central load-bearing section of the conveyor being left unsupported and resiliently deformable. In this way, the central load-bearing section of the conveyor is left unsupported and can be resiliently deformed when required. The coefficient of friction of the runners is also preferably low so that the conveyor belt runs along inside the channels without significant drag.

Advantageously, the runners comprise extruded lengths of a plastics material.

The load-bearing surface of the conveyor belt may be twisted as it ascends or descends. This is preferably achieved by twisting the runners supporting the conveyor belt around one another in the manner of a double helix until each runner has been spiralled through the required angle. Thus, articles which are being transported in a first direction can be elevated or lowered and caused to travel in a second direction, which may be perpendicular to the first direction, on a second, higher or lower horizontal level. There is no limit to the degree of twist which can be imparted to the belt, which can be twisted through 90D and beyond as required, except the twisting properties. of the conveyor belt itself. In practice, however, the fragility of the product being conveyed will determine the degree of twist which may be employed.

The present invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a side elevation of one configuration of a conveyor according to the invention; Fig. 2 is a plan view of the conveyor shown in Fig. 1; Fig. 3 is an end elevation of the conveyor shown in Fig. 1 in the direction of arrow III; Fig 4a is a perspective view, to an enlarged scale, of a short length of a conveyor belt as used in the conveyor shown in Figs. 1 to 3; Fig. 4b is a cross-section along the line IVb-IVb in Fig 4a; Fig. 5 is a transverse section, to an enlarged scale, along the line V-V in Fig. 1 showing a first embodiment of a guide rail in the form of a brush strip; Fig. 6 is a side elevation of the brush strip shown in Fig. 5; Fig. 7 is a transverse section of a second embodiment of guide rail; and Fig. 8 is a perspective view of a twisting ascending or descending portion of a conveyor according to the invention, the conveyor belt, guide rail, and side cladding having been removed to reveal internal details thereof.

The exemplary configuration of a conveyor 1 according to the invention as shown in Figs. 1 to 3 comprises a first horizontal section 2, which is supported by legs 3; a first vertical section 4 for elevating articles; a second horizontal section 5, which is at a level higher than the first horizontal section 2 and also perpendicular to it; a second vertical section 6 for lowering articles; and a third horizontal section 7, which is at substantially the same level as the first horizontal section 4, runs parallel to it and is similarly supported by legs 3.

It can be seen that the vertical sections 4 and 6 of the conveyor 1 each twist through 90* as they rise and fall so that articles initially travelling in a first direction along the conveyor 1 are elevated to travel horizontally in a second, perpendicular direction before being lowered to resume travel in substantially the same direction as initially but in a parallel vertical plane. In this way, the conveyor 1 can be used in handling systems comprising a plurality of various types of conveyors to provide access to doorways and similar and to wind a conveying path between fixed obstacles. This is an important advantage of the conveyor 1 over conventional handling systems, particularly as the conveyor 1 is not bulky, needing to be little wider than the width of the product itself.

It will be appreciated that a conveyor 1 according the present invention can be configured in many different ways dependent on the particular application. The particular configuration shown in Figs. 1 to 3, however, demonstrates the ability of the conveyor to elevate and lower articles vertically and to twist into different directions. These features of the conveyor 1 as well as its more basic construction will now be described in more detail.

The conveyor 1 comprises an endless conveyor belt 8 above which is mounted at least one guide rail 9 located substantially centrally of the belt 8. For the conveyance of some articles a single guide rail 9 is sufficient.

However, two or more parallel guide rails 9 can be used spaced apart equidistantly on each side of the mid-line of the belt, as shown in Figs. 1 to 3 and in Fig. 5, for the particular conveyance of long, floppy articles.

The conveyor belt 8 is supported at its edges in opposing runners 10 which are rigidly secured to side cladding 11. The cladding 11 is itself supported either by the legs 3 or, in twisting portions of the conveyor 1, by another supporting structure as is described below. The runners 10 define opposing pairs of parallel C-section guide channels 12A, 12B into which the opposed edges of the belt 8 slot. The uppermost opposed channels 12A support the load-bearing surface of the belt 8 whereas the lowermost opposing channels 12B support the returning belt 8. The runners 10 defining the channels 12A,12B are made from extruded lengths of polyethylene or a similar plastics material in order to ensure that the coefficient of friction of the surfaces of the channels 12A, 12B is low.

In this way the conveyor belt 8 can run along the channels 12A, 12B without significant drag.

As shown in Fig. 4, the conveyor belt 8 itself comprises a series of links 13, 14 which are hinged together transversely across the width of the belt 8 by means of resiliently flexible rods 15. The rods 15 preferably comprise extruded lengths of polypropylene or a similar resilient plastics material whereby when the belt is supported at its edges in the channels 12A, the rods 15 can flex making the central load-bearing surface of the belt 8 springy and resilient.

The links 13 are located at the edges of the conveyor belt 8 and are preferably made of a plastics material with a low coefficient of friction and which is compatible with the material forming the channels 12A, 12B to ensure smooth running of the belt 8. However, the links 14 comprising the central portion of the belt 8 are made of a flexible elastomeric material, such as synthetic rubber, with a roughened load-bearing surface to provide grip. Typically, these links 14 have a dimpled load-bearing surface in order to engage frictionally articles being transported on the belt 8 whilst also adding to the springy property of the belt 8 as a whole.

The undersurface of at least the links 13 at the edges of the belt 8 each define at least one recess 16 whereby the belt 8 as a whole defines a regular series of such recesses 16 along its lower edges. These recesses 16 are engaged in turn by one or a plurality of sprocket wheels 17, which are driven by a motor 18, as shown in Figs. 1 to 3. In this way a single motor 18 can be used to power the belt 8. Undriven guide rollers 19, which may also comprise sprockets, are used to support the belt as it departs from the channel 12B to travel around the sprocket wheels 17 and also at the ends of conveyor 1 where the belt 8 turns over either to come into use or return.

Despite the frictional engagement of articles on the belt 8 hy its central links 16, at an inclination of 28 and above, the frictional grip of this and other conventional conveyor belts alone on most articles is insufficient to support them. The provision of the guide rail 9, however, enables the conveyor 1 according to the present invention to transport articles upwards and downwards between angles of 30 and the vertical and beyond so that, if necessary, the articles can be inverted.

The guide rail or rails 9 are supported a predetermined distance H above and parallel to the inclined and vertical load-bearing surfaces of the conveyor belt 8 by a series of clamps 20 attached by regularly spaced brackets 21 secured to the outer sides of the cladding 11.

In the vertical sections of the conveyor 1, the brackets 21 can assist in the securement of the cladding 11 to the conveyor.

The spacing H between each guide rail 9 and the surface of the belt 8 must be determined in accordance with the particular articles to be conveyed in each case and the nature of the guide rail 9. The spacing should be substantially comparable to the height of the articles to be conveyed above the load-bearing surface of the conveyor belt 8. In this way, each article is supported by the guide rail 9 against the belt 8 so as to be frictionally gripped by the belt for movement therewith.

It is sufficient for the conveyance of the articles for them to be frictionally supported between the conveyor belt 8 and the guide rail 9 without any deformation of the belt. However, if articles are to be transported which are not delicate and can withstand a certain degree of external pressure but which would only be supported by small areas of the belt, for example small metal components, then the spacing between the rail 9 and the surface of the belt 8 when not distorted can be made slightly smaller than the height of the article to be conveyed above the surface of the belt 8. Thus, when the articles reach the start of guide rail 9, the load-bearing surface of the belt 8 is slightly distorted by the pressure of the article on it and the article is thereby gripped between the belt 8 and the rail 9.This clamping effect compensates for any lack of frictional grip of the articles by the belt 8.

In a first embodiment, as shown in Figs. 5 and 6, the guide rail 9 comprises a brush strip 22 comprising a plurality of bristles 23 which project towards the load bearing surface of the conveyor belt 8. The strip 22 bearing the bristles 23 comprises a plastics carrier mounted into a steel backing rail 24, which provides rigidity and strength to the strip 22.

In use, the bristles 23 in contact with an article being transported on the conveyor momentarily clamp it between the guide rail 9 and the belt 8. Preferably, the clamps 20 used to mount the guide rail permit the brush strip 22 to be mounted at various distances from the surface of the belt 8. In this way the pressure exerted by the bristles 23 on the articles to be transported can be adjusted to suit the articles concerned. Lightweight delicate objects will require much less pressure than more robust heavy ones. It will be appreciated that when the guide rail 9 comprises a brush strip 22, the distance H between the brush strip 22 and the load-bearing surface of the belt 9 can be made significantly greater than the height of the articles being conveyed above the loadbearing surface of the conveyor because of the compensating effect of the bristles 23.

As shown in Fig. 6, the bristles 23 are preferably arranged in clumps and angled in a direction pointing towards the direction of travel of the load-bearing surface of the belt 8. This reduces drag on the articles being transported by the bristles 23 in the forward direction of travel whilst at the same time preventing the articles slipping back down the conveyor 1 when it is travelling in an upwards direction. Preferably, the bristles 23 are angled at an angle a which is approximately 30e to a plane normal to the load-bearing surface of the belt 8 and the bristle clumps are spaced by a distance L, which is approximately 12.5 mm long.

In a second embodiment, as shown in Fig. 7, the guide rail 9 comprises a smooth strip 25, which is crimped in an extruded channel section aluminium carrier 26. Here the distance H between the surface of the strip 25 and the load-bearing surface of the belt 9 is made substantially comparable to the height of the articles being conveyed above the belt 9 so that the strip 25 can support each article against the belt and ensure it is frictionally gripped by the belt for movement therewith. However, to ensure the guide rail 9 does not exert unnecessary drag on the articles being conveyed, the strip 25 is preferably made from a material with a low coefficient of friction such as an extruded length of polyethylene or similar plastics material.

As previously indicated, the present invention also permits the conveyed articles to be turned as they are being elevated or lowered by twisting the load-bearing surface of the conveyor belt 8 as it travels out of a horizontal plane and during vertical ascent or descent.

The manner in which the belt 8 is twisted will now be described with reference to Figs. 5 and 8.

With reference to these drawings, it will be seen that as the conveyor 1 ascends the runners 10 twist around one another in the manner of a double helix until each runner 10 has been spiralled through 90 around a vertical axis.

This is possible because the runners 10 are made from extruded lengths of a plastics material which, to a certain extent, enables them to accommodate a degree of twist. By attaching the runners 10 defining the channels 12A, 12B at each side of the conveyor 1 at regularly spaced intervals to spacer blocks 27 which are appropriately bevelled, the required helix structure can be produced.

The blocks 27 are themselves secured to crosspieces 28 which are screwed to a rigid vertically mounted support rod 29. The rod 29 gives rigidity to the structure and runs the whole length of the vertical section of the conveyor 1 centrally between the runners 10. The rod 29 is thereby effectively encased by the cladding 11 covering the runners 10 and the conveyor belt 8 itself.

In the vertical sections of the conveyor, it will appreciated that the cladding 11 does not support the runners 10. Here, the cladding 11 is held in place by the brackets 21 which are secured through the cladding 11 to the bevelled spacer blocks 27.

It will be appreciated that the degree of twist which can be imparted to the conveyor belt 8 depends on its own twisting properties and that of the runners 10. Typically, a resilient belt suitable for use in the present invention can be twisted through 30- for every 250 mm of its length.

However, in practice the degree of twist which can be imparted to the conveyor 1 is determined by the nature of the product. Delicate articles such as confectionery cannot be given too much twist without damage. Preferably, therefore, the degree of twist imparted to the conveyor belt 8 by the runners 10 is no more than 15 for 250 mm of its length.

As previously mentioned, the conveyor according to the invention can be used for transporting articles downwardly as well as upwardly. The structure of the conveyor 1 is the same regardless of the direction of travel of the conveyor belt 8 apart from the direction of the bristles 23 in the brush strip if such a guide rail is used. Hence, in conveyors 1 with a guide rail as depicted in Fig. 7 or similar, the direction of travel of the conveyor belt 8 can be reversed.

Thus, the conveyor according to the invention will convey, inter alia, long, floppy and delicate articles both vertically upwards and vertically downwards and through steep inclines and declines in a safe manner as well as turning the direction of travel when required. The conveyor has been specifically designed for conveying articles such as biscuits and confectionery which are packaged in cellophane wrappers, which has a very low coefficient of friction. Such articles can be conveyed vertically upwardly and downwardly, without damage and without either falling out of the conveyor 1 sideways or slipping down the vertically inclined belt.

Claims

1 A conveyor for conveying articles through an angle of 30 or more with respect to the horizontal comprising a conveyor belt mounted so that its load-bearing surface is springy and resilient and is adapted to engage frictionally an article to be conveyed, and at least one guide rail located parallel to the inclined and/or vertical loadbearing surfaces of the conveyor belt, the spacing between the guide rail and the surface of the belt when not distorted being at least substantially comparable to the height of the article to be conveyed above the load-bearing surface of the conveyor whereby in use the article is supported by the guide rail against the belt so as to be frictionally gripped by the belt for movement therewith.

2. A conveyor as claimed in Claim 1, wherein that portion of the guide rail facing the load bearing surface of the conveyor belt comprises a smooth plastics surface.

3. A conveyor as claimed in Claim 1, wherein the guide rail comprises a brush strip comprising a plurality of bristles which project towards the load-bearing surface of the conveyor belt to clamp said article momentarily between the guide rail and the belt as it is conveyed.

4. A conveyor as claimed in Claim 3, wherein said bristles are angled in a direction pointing towards the direction of travel of the load-bearing surface of the belt.

5. A conveyor as claimed in any one of Claims 1 to 4, wherein the guide rail is located substantially centrally of the belt.

6. A conveyor as claimed in any one of Claims 1 to 4, wherein a pair of parallel guide rails is provided, the rails being equidistantly spaced on either side of the midline of the belt.

7. A conveyor as claimed in any one of Claims 1 to 6, wherein the conveyor belt is supported at its edges in runners and comprises a series of links which are hinged together by means of resiliently flexible rods.

8. A conveyor as claimed in Claim 7, wherein the rods comprise extruded lengths of a resilient plastics material.

9. A conveyor as claimed in Claim 7 or Claim 8, wherein at least the central portion of the conveyor belt is made of flexible elastomeric links with a roughened load-bearing surface to provide grip.

10. A conveyor as claimed in any one of Claims 7 to 9, wherein the runners supporting the conveyor belt comprise channels in which opposed edges of the conveyor belt are located, the central load-bearing section of the conveyor being left unsupported and resiliently deformable.

11. A conveyor as claimed in Claim 10, wherein the runners comprise extruded lengths of a plastics material.

12. A conveyor as claimed in any one of Claims 1 to 11, wherein the load-bearing surface of the conveyor belt is twisted as it ascends or descends.

13. A conveyor as claimed in Claim 12, wherein the runners supporting the conveyor belt twist around one another in the manner of a double helix.

14. A conveyor as claimed in Claim 13, wherein the runners supporting the conveyor belt spiral around a vertical axis.

15. A conveyor as claimed in Claim 13 or Claim 14, wherein the degree of twist imparted to the conveyor belt by the runners is no more than 15 for 250 mm of its length.

16. A conveyor for conveying articles through an angle of 30* or more with respect to the horizontal substantially as described herein with reference to any one or more of the accompanying drawings.

16. A conveyor for conveying articles through an angle of 30 or more with respect to the horizontal substantially as described herein with reference to any one or more of the accompanying drawings.

Amendments to the claims have been filed as follows 1 A conveyor for conveying articles through an angle of 300 or more with respect to the horizontal comprising a conveyor belt with a load bearing surface adapted to engage frictionally an article to be conveyed and mounted so that the load-bearing surface is supported at its edges by runners with its central load-bearing section left unsupported and thereby resiliently deformable, and at least one guide rail located parallel to the inclined and/or vertical load-bearing surfaces of the conveyor belt, the spacing between the guide rail and the load-bearing surface of the belt when not distorted being at least substantially comparable to the height of the article to be conveyed above the load-bearing surface of the conveyor, whereby in use the article is supported by the guide rail against the belt so as to be frictionally gripped by the belt for movement therewith.

7. A conveyor as claimed in any one of Claims 1 to 6, wherein the conveyor belt comprises a series of links which are hinged together by means of resiliently flexible rods.

9. A conveyor as claimed in Claim 7 or Claim 8, wherein at least the central pnrtjon of the conveyor belt is made of flexible elastomeric links with a roughened load-bearing surface to provide grip.

10. A conveyor as claimed in any one of Claims 7 to 9, wherein the runners supporting the conveyor belt comprise channels in which opposed edges of the conveyor belt are located.

13. A conveyor as claimed in Claim 12, wherein the runners sllpporting the conveyor belt twist around one another in the manner of a double helix.

]4. A Conveyor as claimed in Claim 13 wherein the runners supporting the conveyor belt spiral around a vertical axis.

15. A conveyor as claimed in Claim 13 or Claim 14, wherein the degree of twist imparted to the conveyor belt by the runners is no more than 15- for 250 mm of its length.