WO2003024846A1

WO2003024846A1 - Conveyor

Info

Publication number: WO2003024846A1
Application number: PCT/NL2002/000602
Authority: WO
Inventors: Wouter Balk
Original assignee: Ambaflex International B.V.
Priority date: 2001-09-20
Filing date: 2002-09-19
Publication date: 2003-03-27
Also published as: NL1018994C2

Abstract

A conveyor for conveying piece goods through a helical path in upright direction comprises a frame and an endless conveyor belt having a conveying part guided in the helical path and a return path. The conveyor belt includes substantially rigid support members movably coupled to each other and having an upper transport face. The support members are coupled to each other at their adjacent edges and are also interconnected at their radially outer edge by means of a strengthening element extending in the conveying direction. At least a number of support members is provided with at least a guide roller rotatable about a rotation axis and adapted to roll along a helical guide surface guiding the rollers in substantially radial direction. The guide rollers are positioned near the radially outer edge.

Description

Conveyor

The invention relates to a conveyor for conveying piece goods and the like through a helical path in vertical direction (also called spiral conveyor) .

Such conveyors are known in various versions thereof in practice, for example from EP-A-1 009 692. Such conveyors are very suitable for bridging a relatively great height without using an overly large pitch, because it is possible to use a large number of windings. Such conveyors comprising a conveyor belt consisting of slats are not suitable for some applications, for example in the foodstuffs industry and in bottling plants, where easily cleanable or fine-meshed conveyor belts are required.

Such conveyor belts are indeed available, as disclosed in US-B-6,216, 854 and US-A-5, 573 , 105 , for example. However, these conveyor belts are not suitable for use in spiral conveyors .

US-A-3 , 854 , 575 discloses a conveyor system in which the horizontal conveyor belts travel around curves of 90° or 180°. The conveyor belt of said system does not extend in a helical path, therefore.

The object of the present invention is to provide a conveyor in which the aforesaid problems have been eliminated in an efficient manner.

To this end, the invention provides a conveyor as defined in claim 1.

The conveyor according to the invention uses a conveyor belt comprising directly coupled support members, which provide a closed surface and which can easily be rendered suitable for use in the foodstuffs industry. The use of a strengthening element and guide rollers makes it possible to guide the conveyor belts in a helical path without producing excessive friction resistance, which might lead to the much- dreaded noose effect. Furthermore, the guide rollers and the strengthening element enable the conveyor to withstand great forces and realise high speeds. In an advantageous embodiment, the axes of rotation of the guide rollers are positioned outwardly of the radial centres of the supporting members, preferably near the radially outer edge thereof, seen in relation to the frame. In an even more advantageous embodiment, the guide surface and the supporting surface of the frame are arranged on a section which comprises a shoulder above the guide surface, under which the guide rollers engage .

The above aspects lead to a stable radial support of the conveyor belt at low frictional forces. Furthermore, the guide rollers function to prevent upward movement of the conveyor belt. As a result, no additional elements are required for this purpose.

In a special embodiment of the conveyor belt according to the invention, which is especially suitable for use in a spiral conveyor, the support members are segmental in shape and they are interconnected in such a manner that the support members are maximally movable relative to each other between a position in which the conveyor belt is at least substantially straight and a position in which the radius of curvature of the conveyor belt at least substantially corresponds to that of the , helical path

The invention will be explained in more detail hereinafter with reference to the drawing, which shows an embodiment of the conveyor according to the invention.

Fig. 1 is a general, schematic side view of the embodiment of the conveyor according to the invention.

Fig. 2 is a top plan view of the conveyor that is shown in Fig. 1. Fig. 3 is a larger-scale cross-sectional view of the conveyor that is shown in Figs. 1 and 2.

Figs. 4, 5 and 6 are even larger-scale views, in plan view, front view and side view, respectively, of the conveyor belt of the conveyor of Figs . 1 - 3. Fig. 7 is a view corresponding to Fig. 5, in which an alternative embodiment of the conveyor belt is shown, however.

The drawing shows a conveyor which is capable of transporting products, in particular piece goods, through a helical path in upward direction. In practice such conveyors are also known as spiral conveyors or winding conveyors. Said conveyors are capable of transporting products in a continuous flow, which product flow may be intended for vertical transport or for buffering in a process section. The conveyor according to the invention is in particular, but not exclusively, suitable for transporting small goods, such as loose bottles large and small, cans, pots and the like. Possible areas of utilization include the foodstuffs industry (bottling plants, the meat processing industry, bakeries, etc.), distribution centres, the graphics industry and the like. In such applications transport generally takes place at high velocities, whereas great forces are exerted on the conveyor belt, especially in those cases where a larger number of windings are used. The conveyor as shown (refer in particular to Figs. 1

- 3) comprises a frame 1, in this case including a central column 2 having feet 3 and a helical guide chute 4 extending round the column 2 and being fixed thereto. Various kinds of frame constructions are conceivable, of course. A reversing element 5, 6 (in this case a shaft with a number of chain wheels) is arranged on the upper and lower ends of the guide chute, and a vertical return chute 7 of the frame 1 extends between said ends of the helical guide chute 4. In this case the conveyor belt 8 supported by the frame 1 travels in different paths in the conveying part and in the return part, therefore.

Embodiments in which the conveying part is guided back along the bottom side of the guide chute 4 are also possible, however. In the illustrated embodiment, the return part travels in a quarter-circle path under the conveying part upon so as to be guided from the vertical return chute 7 to the reversing element 5.

In the illustrated embodiment, the helical guide chute 4 comprises four windings, which number may be larger or smaller, depending on the specific use. The invention makes it possible to drive the conveyor belt 8 through a large number of windings (for example maximally 12 windings) without any driving problems. In the illustrated embodiment, a driving motor 9 engages the upper reversing element 6 at the end of the conveyor path, and in addition to that, auxiliary driving units may be used at different places along the conveyor path. It is also possible for the conveyor belt 8 to be driven linearly. At the upper and lower reversing elements 5, 6, further conveyors may connect linearly or laterally to the conveyor. If the conveyor is used in bottling plants, said connection will be a lateral connection in many cases, and a push-off element will transfer the bottles laterally to another conveyor. The frame is locally narrowed and does not comprise an upright edge at that location. As is shown in particular in Fig. 3, the conveyor belt

8 comprises a large number of support members 10 which are directly coupled to each other, preferably along the entire length of their adjacent edges, thus forming a closed conveying surface. Each support member has an upper, flat conveying surface, and the support members 10 join one another so closely in the direction of their path of movement, such that products can be supported by a number of support members arranged adjacently to each other. As already said before, the support members 10 are pivotally interconnected either directly or, in this case, via an endless strengthening element yet to be described, in such a manner that the support members 10 can pivot with respect to each other, both about a first axis extending parallel to their plane of transport and perpendicularly to the conveying direction, and about a second axis extending perpendicularly to their conveying surface and perpendicularly to the conveying direction. The latter pivoting movement allows the formation of the helical path, whereas the former pivoting movement makes it possible for the conveyor belt 8 to pass over the end pulleys 5 and 6. As is shown in particular in Figs. 2 and 3, the guide chute 4 of the frame 1 comprises radial spokes, on which helical sections 11, 12 (consisting of plastic material with a metal core) having an upper supporting surface 13 are present, on which the support members 10 rest with their bottom side, so that the support members 10 are slidably supported by the supporting surfaces 13 during their movement . A suitable selection of the materials of the (plastic) sections 11 and 12 and the (plastic) support members will help to keep the level of friction and wear low.

Fig. 4 also shows that the support members 10 consist of elongated elements comprising (in this case) two rows of teeth 15, 16, which are connected in the longitudinal centre of the support member 10. The teeth in the two rows are staggered relative to each other, in such a manner that the facing teeth 15, 16 of adjacent support members 10 can mesh with each other. Holes are formed through the teeth 15, 16, parallel to the adjacent edges of the support members. The holes 17 in the teeth 15 are circular in shape, whereas the holes 17' in the teeth 16 are elongated in the conveying direction. A pin 18, preferably made of steel, extends through the holes 17 and 17' (see Fig. 6), which pin interconnects adjacent support members 10 in such a manner that there is some play between the adjacent support members 10 in the conveying direction, which play results from the fact that the pin 18 is accommodated in the elongated holes 17' with some play. This pin-hole construction enables the relative pivoting movements of the support members 10 as described above. Furthermore, movement of the support members towards and away from each other is possible.

The support members 10 are made of plastic material, and consequently they are not sufficiently capable of withstanding the forces that occur at high speeds or high loads . Consequently, the conveyor belt 8 comprises at least one strengthening element 19 at its radially outer edge, where said forces are greatest, which strengthening element 19 is provided with steel links 20 in this case, which are passed over the adjacent pins 18, so that an entirely steel connection between the support members 10 and the conveyor belt 8 is formed in the maximally extended position of the support members 10, which provides great strength. The elongated holes in each link 20 of the strengthening element 19 ensure that movement of the support members 10 towards and away from each other remains possible. In the illustrated embodiment of the support members

10, the teeth 15 and 16 are provided with vertically extending openings in the shape of slots 21. In this case, said slots 21 are used for mounting guide rollers 22 which are attached to every second support member 10 at positions some distance away from the radially outer edge of the conveyor belt 8 in this case. The guide rollers 22 consist of a ball bearing or other type of roller bearing in this case, which is fixed to a holder by means of a screw 23. The holder 24 has two projections 25, which engage in the slots 21 of two adjacent teeth 15. In order to obtain a locking engagement of the projections 25 in the slots 21, the projections 25 partially engage around the associated pin 18, which is fixed to the support member 10 in question. After all, each pin 18 is mounted in the teeth 15 without play, whereas it is mounted in the teeth 16 of the adjacent support member with some play. The holder 24 of the guide rollers 22 is shaped such that the axis of rotation of the guide rollers 22 intersects the longitudinal axis of the support member 10 in question.

As Fig. 3 shows, the helical section 12 of the frame 1 comprises an at least substantially radially extending guide surface 14 in addition to the supporting surface 13, along which guide surface the guide rollers 22 can roll with their outer circumference so as to provide a rolling guidance and support of the conveyor belt 8 in radial direction. Stable guidance is provided by positioning the guide rollers 22 near the radially outer edge of the conveyor belt 8.

The section 12 has a shoulder 27 above the guide surface 14, under which the guide rollers 22 engage, and which consequently acts as a hold-down which prevents the conveyor belt 8 from lifting. This tendency of the conveyor belt 8 to lift is greatest near the radially outer edge of the conveyor belt, so that it is advantageous in this case as well that the guide rollers 22 are positioned near the outer edge.

An alternative embodiment of the conveyor belt 8 is shown in Fig. 7. In this embodiment the strengthening element is a so-called sidebow roller chain 26, which is commonly known in the field of transport. Said roller chain allows limited bending transversely to the normal direction of pivoting of the links. The attachment of the roller chain 26 to each support member 10 takes place via a fastening element 27, into which one or more pins of the links are snapped and which is movably or immovably mounted on the outer side of the support member 10 in question. Said roller chain 26 can also be used for driving the conveyor belt, because a chain wheel can engage the chain from below. In this embodiment, the guide roller 22 may be attached to the support member in the same manner as in the preceding embodiment, but it is also possible to mount said guide roller 22 on the fastening element 27. The interplay of forces of the drive mechanism and the radial support of the support members 10 takes place entirely on the outer side of the conveyor belt in that case, making it possible to use thinner or otherwise less strong support members 10, because the forces that are passed through the support members are not so large.

Further alternatives for the strengthening element comprise (steel) cables, (kevlar) strings and similar flexible and strong elements which enable a simple construction.

In a special case, the support members 10 may be segmental and be interconnected in such a manner that the . support members are maximally movable with respect to each other between a position in which the conveyor belt is at least substantially straight and a position in which the radius of curvature of the conveyor belt at least substantially corresponds to that of the helical path. The radius of curvature of the conveyor belt can be smaller in that case, so that conveyors having a smaller diameter can be constructed. The outer strengthening element may be a non-telescopic element in this case, such as the aforesaid side bow chain. The support members 10 take up a substantially fixed position (in the conveying direction) relative to each other at their radially outer edges, i.e. the support members are fixed in their maximally extended position at that location. Bending of the conveyor belt takes place by sliding the support members into each other at their radially inner edges. This can also be affected with normal rectangular support members.

From the foregoing it will be apparent that the invention makes it possible, using simple and reliable means, to drive a conveyor belt formed of fine-meshed links, which is guided through a helical path, through a large number of windings without any driving problems and without affecting the support member construction.

The invention is not restricted to the embodiment as described above and shown in the drawing, which can be varied in many ways within the scope of the invention.

Claims

1. A conveyor for conveying piece goods through a helical path in a vertical direction, comprising a frame, an endless conveyor belt supported by said frame and driven by drive means, which endless conveyor belt has a conveying part guided in said helical path and a return part, and which includes movably interconnected, substantially rigid support members having an upper conveying surface, which support members are pivotable relative to each other both about a first axis extending parallel to said conveying surface and perpendicularly to the conveying direction and about a second axis extending perpendicularly to said conveying surface and perpendicularly to the conveying direction, wherein said support members are coupled to each other at their adjacent edges and are also interconnected at their radially outer edge by means of a strengthening element extending in the conveying direction, and wherein the frame comprises a helical supporting surface for sliding support of the support members in the conveying part, whereas the frame furthermore comprises a helical guide surface for guiding said support members substantially radially in said conveying part, wherein at least a number of support members includes at least one guide roller which is rotatable about an axis of rotation extending parallel to the second axis and which is adapted to roll along said guide surface.

2. A conveyor according to claim 1, wherein the axes of rotation of said guide rollers are positioned outwardly of the radial centre of the support members .

3. A conveyor according to claim 2, wherein the axes of rotation of said guide rollers are positioned near the radially outer edge of the support members .

4. A conveyor according to any one of the preceding claims, wherein the guide surface and the supporting surface of the frame are arranged on a section which comprises a shoulder above the guide surface, under which the guide rollers engage.

5. A conveyor according to claim 4, wherein the guide rollers are cylindrical and wherein the guide surface is at least substantially vertical, whereas the guide rollers are preferably roller bearings.

6. A conveyor according to any one of the preceding claims, wherein each guide roller is attached to a holder comprising at least one projection which is inserted in an opening in the support members .

7. A conveyor according to any one of the preceding claims, wherein the support members are coupled at their adjacent edges by means of pins extending along said edges of the support members, which pins preferably extend through openings which exhibit some play relative to said pins in a direction at least substantially parallel to the conveying surface .

8. A conveyor according to claims 6 and 7, wherein the pins in question intersect the openings for the projections of the holders of the guide rollers and wherein said projections engage at least partially round the pins in question.

9. A conveyor according to any one of the preceding claims, wherein the support members are segmental in shape and they are interconnected in such a manner that the support members are maximally movable relative to each other between a position in which the conveyor belts is at least substantially straight and a position in which the radius of curvature of the conveyor belt at least substantially corresponds to that of the helical path

10. A conveyor according to claim 9, wherein the mutual distance between the support members at the radially outer edges is at least substantially constant.

11. A conveyor according to any one of the preceding claims, wherein said strengthening element includes at least one side bow chain, which is preferably attached to the various support members via fastening elements, whereas the drive means are preferably provided with chain wheels which mesh with the side bow chain.

12. A conveyor according to any one of the claims 1 -

10, wherein the strengthening element comprises a strong cable or string.