GB2072123A

GB2072123A - Helical conveyor

Info

Publication number: GB2072123A
Application number: GB8108343A
Authority: GB
Original assignee: Ammeraal Nederland BV
Current assignee: Ammeraal Nederland BV
Priority date: 1980-03-24
Filing date: 1981-03-17
Publication date: 1981-09-30
Also published as: NL8001706A; GB2072123B; JPS56145006A; DE3109942A1; FR2478594A1

Abstract

An endless conveyor belt 7 passes over upper and lower cylindrical end rollers 2 each comprising freely rotatable discs. The upper and lower runs 7%, 7_ are parallel to each other adjacent the rollers 2 and over most of the remainder of their length, except at the location of a drive 15, 16. The outer edge of the belt 7 has rollers (8) which run on helical guide walls (10) lying on a common cylindrical surface. <IMAGE>

Description

SPECIFICATION Helical conveyor The invention relates to a helical conveyor for transport along a helical path having a central axis which extends at least approximately vertically, comprising an upper and a lower end member and an endless conveyor belt passing over these end members.

In the known embodiments of such helical conveyors the upper run and the lower run of the conveyor belt enclose an oblique angle with each other, in particular in the areas adjoining the end members, which consist of conical end rollers, but in general also along their further length. This results in that the blank of the conveyor belt cannot be determined optimally throughout its entire path, but a compromise has to be found between the blanks of the upper run and of the lower run of the conveyor belt. However, this gives rise to large tensions in the conveyor belt, while this conveyor belt swings quite appreciably during operation. This leads to a great deal of noise as well as to heavy wear.

With a view to removing these difficulties, the present invention provides a helical conveyor in which the upper run and the lower run of the conveyor belt are parallel to each other in the areas adjoining the end members and in at least the major part of their further length.

More particularly, the upper run and the lower run of the conveyor belt may be parallel to each other with the exception of the location of a drive for the lower run of the conveyor belt.

In a helical conveyor according to the invention the blank of the conveyor belt can be determined very exactly, being substantially identical for the upper run and the lower run. This results in that tensions arising in the conveyor belt are appreciably diminished, while swinging of the conveyor belt during operation is reduced to a minimum. In this way the noise developed is lessened considerably and that the useful life of the conveyor belt is appreciably increased.

A further disadvantage of the known helical conveyors consists in that a complicated weld connection is necessary for making the conveyor belts endless, in order to try to compensate at least to some extent for the faulty blank of the conveyor belt. This welding operation is very time consuming and requires a high degree of skill.

According to the invention, however, the conveyor belt may be made endless by means of a simple straight finger weld.

In a known helical conveyor the outer part of the conveyor belt is provided with a plurality of retaining members, which engage stationary guides along both the upper and the lower run of the conveyor belt. According to the invention it is preferred that the guides for the upper and the lower run of the conveyor belt have the same shape and are parallel to each other.

In the known helical conveyor each retaining member consists of a lower and an upper roller, which are rotatably mounted on a shaft led at right angles through the outer part of the conveyor belt and fastened thereto, while the stationary guides on the outer side of the conveyor belt for the upper run and for the lower run of the conveyor belt each comprise a pair of cooperating upper and lower wall portions, which form an intermediate slot for the conveyor belt, the outer surfaces of these upper and lower wall portions cooperating with the rollers. According to the invention it is considered to be an advantage if the upper and lower wall portions of both guides lie at least approximately on a common cylindrical surface.

In a very simple embodiment of the helical conveyor according to the invention, wherein the end members consist of end rollers, these end rollers are cylindrical and have at least approximately horizontal axes. The end rollers may be non-driven idle rollers and may be composed of a plurality of discs which are rotatable with respect to each other in order to be able to take up differences in speed arising between parts of the conveyor belt lying on different radii without incurring any major frictional losses.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of part of a helical conveyor; and Fig. 2 is a partial section along the line Il-Il in Fig. 1 on a larger scale.

The helical conveyor illustrated serves for transport along a helical path having a central axis which extends vertically.

This helical conveyor is composed of a plurality of adjoining sections 1'. Of course, the helical conveyor 1 may also be designed as a single unit.

Each section 1' comprises an upper and a lower cylindrical end roller 2, which rollers 2 are rotatably mounted on a central cylindrical core 3 with a vertical longitudinal axis and on an outer frame 4 that comprises a plurality of uprights 5 which are equally spaced from the central axis and which are connected to the core 3 by means of connecting arms 6. The end rollers 2 have an at least approximately horizontal central axis and are not driven. Preferably the end rollers 2 are composed of a plurality of discs which are rotatable with respect to each other. As an alternative to the end rollers 2 it is possible to use non-rotatable end members.

An endless conveyor belt 7 is passed over the two end rollers 2. The upper run 7' and the lower run 7D of the conveyor belt 7 are parallel to each other with the exception of the location of a drive (described below) for the lower run 7". The conveyor belt 7 is made endless by means of a straight finger weld (not shown).

The conveyor belt 7 is provided at the outer side at spaced locations with pairs of lower and upper rollers 8, rotatably mounted on respective shafts led at right angles through the conveyor belt 7 and connected to the conveyor belt 7. The upper and lower rollers 8 cooperate with upper and lower stationary guides 9 which are connected to the inner side of the uprights 5. The guides 9 for the upper run 7 and for the lower run 7" have an identical helical shape and are parallel to each other.

Both for the upper run 7' and for the lower run 7" the guides 9 comprise lower and upper wall portions 10 which are helically bent in the longitudinal direction. The wall portions 10 of each guide 9 are positioned one above the other and form an intermediate helical slot through which the upper run 7' or the lower run 7" extends. The outer surfaces of the wall portions 10 cooperate with the rollers 8 and lock the conveyor belt 7 against an inwardly directed displacement, whilst the upper run 7' and the lower run 7" obtain a helical shape. The upper and lower wall portions 10 of both guides 9 lie on a common cylindrical surface.These wall portions 10 are detachably connected by means of screws to carriers 1 1, which are connected either to girders 12 between an upright 5 and the cylindrical core 3, or directly to an upright 5.

The guides 9 for the rollers 8 of the upper run 7' and for the rollers 8 of the lower run 7" end at each extremity in the immediate proximity of the end rollers 2. The rollers 8 of the conveyor belt 7 consequently leave the one guide 9 at each end roller 2 and come again into engagement with the other guide 9 beyond the end roller 2 concerned.

The girders 12 carry support rollers 13 for the upper run 7' and guide rollers 14 for the lower run 7t of the conveyor belt 7. The lower run 7" is looped over a conical drive drum 15 which is coupled to a drive means (not shown) with a reversible direction of rotation. The conical drive drum 15 cooperates on each side with a conical guide drum 16, over which the lower run 7" is passed as shown in Figure 1. Of course, the guide 9 for the rollers 8 of the lower run 7" of the conveyor belt 7 is interrupted at the location of the drive.

In helical conveyor described above tensions in the conveyor belt 7 may be kept quite low and the conveyor belt 7 runs quietly in operation, without swinging, so that the helical conveyor produces little noise. The cylindrical end rollers 2 may have a small diameter, so that the runs 7' and 7" of the conveyor belt 7 lie only a small distance apart from each other.

Claims

1. A helical conveyor for transport along a helical path having a substantially vertical central axis, comprising an upper and a lower end member and an endless conveyor belt passing over the end members, the upper run and the lower run of the conveyor belt being parallel to each other in the areas adjoining the end members and in at least the major part of the remainder of their length.

2. A helical conveyor as claimed in claim 1, in which the upper run and the lower run of the conveyor belt are parallel to each other between the end members except at the location of a drive for the lower run.

3. A helical conveyor as claimed in claim 1 or 2, in which the conveyor belt is made endless by means of a straight finger weld.

4. A helical conveyor as claimed in any preceding claim, in which the outer part of the conveyor belt is provided with a plurality of retaining members which engage stationary guides along both the upper and the lower run, the guides for the upper and the lower run having the same shape as each other and being parallel to each other.

5. A helical conveyor as claimed in claim 4, in' which each retaining member consists of a lower roller and an upper roller which are rotatably mounted on a shaft led at right angles through the outer part of the conveyor belt and fastened thereto, the stationary guides on the outer side of the conveyor belt for the upper run and for the lower run each comprise a pair of upper and lower wall portions which define between them a slot for the conveyor belt, the outer surfaces of the wall portions cooperating with the respective rollers, and the upper and lower wall portions of both guides lie substantially on a common cylindrical surface.

6. A helical conveyor as claimed in claim 4 or 5, in which the guide for the retaining members of the lower run is interrupted at the location of a drive for the lower run.

7. A helical conveyor as claimed in any preceding claim, in which the end members consist of cylindrical rollers having substantially horizontal axes.

8. A helical conveyor as claimed in claim 7, in which the end rollers are idle rollers.

9. A helical conveyor as claimed in claim 7 or 8, in which the end rollers comprise a plurality of discs which are rotatable with respect to each other.

10. A helical conveyor substantially as described with reference to, and as shown in, the accompanying drawings.

10. A helical conveyor as claimed in any preceding claims, in which the lower run of the conveyor belt is looped over a conical drive drum which is coupled to a drive means.

11. A helicai conveyor as claimed in claim 10, in which the direction of rotation of the drive means is reversible.

12. A helical conveyor as claimed in claim 10 or 11, in which the conical drive drum is located between two conical guide drums over which the lower run of the conveyor belt is passed.

13. A helical conveyor substantially as described with reference to, and as shown in, the accompanying drawings.

New claims or amendments to claims filed on 1 st July 1981.

Superseded claims 1 to 13.

New or amended claims

1. A helical conveyor for transport along a helical path having a substantially vertical central axis, comprising an upper and a lower end member and an endless conveyor belt passing over the end members, the end members consisting of cylindrical rollers having substantially horizontal axes, the upper run and the lower run of the conveyor belt being parallel to each other between the end members except at the location of a drive for the lower run, the outer part of the conveyor belt being provided with a plurality of retaining members which engage stationary guides along both the upper and the lower run, the guides for the upper and the lower run having the same shape as each other and being parallel to each other.

2. A helical conveyor as claimed in claim 1, in which the conveyor belt is made endless by means of a straight finger weld.

3. A helical conveyor as claimed in claim 1 or 2, in which each retaining member consists of a lower roller and an upper roller which are rotatably mounted on a shaft led at right angles through the outer part of the conveyor belt and fastened thereto, the stationary guides on the outer side of the conveyor belt for the upper run and for the lower run each comprise a pair of upper and lower wall portions which define between them a slot for the conveyor belt, the outer surfaces of the wall portions cooperating with the respective rollers, and the upper and lower wall portions of both guides lie substantially on a common cylindrical surface.

4. A helical conveyor as claimed in any preceding claim, in which the guide for the retaining members of the lower run is interrupted at the location of a drive for the lower run.

5. A helical conveyor as claimed in any preceding claim, in which the end rollers are idle rollers.

6. A helical conveyor as claimed in any preceding claim, in which the end rollers comprise a plurality of discs which are rotatable with respect to each other.

7. A helical conveyor as claimed in any preceding claim, in which the lower run of the conveyor belt is looped over a conical drive drum which is coupled to a drive means.

8. A helical conveyor as claimed in claim 7, in which the direction of rotation of the drive means is reversible.

9. A helical conveyor as claimed in claim 7 or 8, in which the conical drive drum is located between two conical guide drums over which the lower run of the conveyor belt is passed.