WO1999061352A1

WO1999061352A1 - A chute

Info

Publication number: WO1999061352A1
Application number: PCT/DK1999/000281
Authority: WO
Inventors: Erik Lünell BRUHN; Bente HØEGH; Carsten Raunsbaek
Original assignee: Crisplant A/S
Priority date: 1998-05-22
Filing date: 1999-05-25
Publication date: 1999-12-02
Also published as: AU4133399A

Abstract

A chute segment for building up a chute which may be comprised in a discharge or unloading station in a conveyor and/or sorting system. Articles may be conveyed under action of gravity along a conveying path defined by surface parts of the chute segments. The chute is built up of a plurality of chute segments. The chute segment is at least partly hollow and is made as a shell part having an outer shell which is made from a plastics or composite material and which defines one or more inner cavities. The inner cavities may be filled by a filling material, e.g., in the form of a foam or by a honeycomb structure in order to improve the stiffness and the stability of the chute segment. The chute may have a spiral- or helix-like configuration. A method for manufacturing the chute segment comprises rotational moulding of at least the shell part. A method for joining chute segments is disclosed.

Description

A CHUTE

TECHNICAL FIELD

The present invention relates to a chute, in particular a chute having a substantially helicoid shape, the chute being built up of a plurality of chute segments. The present invention further relates to a chute segment for such a chute, a method of manufacturing such a chute segment and a method of joining two or more chute segments so as to build up a chute.

The chute is in particular suited for conveying articles, such as mail bags, luggage, postal packages, factory products or other items. The chute may be arranged adjacent to a conveyor system along which the articles are being conveyed, and normally sorted, in such a way that articles, when having been discharged from the conveyor system, are being further conveyed along the chute due to gravity.

BACKGROUND OF THE INVENTION

Chutes, including helicoid chutes, which are built up of two or more chute segments are known perse. Such chutes are built up of chute segments each spanning over an angle of approximately 45^° or 90^°, the chute segments being usually made from steel, fibre glass or wood which may optionally be provided with surface coating.

GB 944,566 discloses a fibreglass spiral chute developed with the object of providing a light and easy to handle chute. GB 2 191 177 discloses a braking system for a fibreglass spiral chute having a braking system for slowing down objects at the top of the chute, the chute being built up of a number of adjacent spiral sections being secured together by bolted flanges. DE 91 01 796 U1 discloses a chute segment made from metal and spanning circularly over an angle of 45^° or more, the chute segment being adapted to be welded to an adjacent chute segment in a spiral chute. A chute for a tilt tray sorter is known from US 5,220,986, the chute comprising a rectangularly shaped support backing formed from plywood and a sheet of low friction, wear resistant polymeric material bonded to the upper surface of the support backing. US 3,565,226 discloses a special geometric configuration of a spiral chute. When building up chutes from prior art chute segments, the total length of the conveyor path provided by the chute is normally adjusted by manufacturing one or more chute segments having specially adapted dimensions. Usually it is not possible to build up standard sized chutes, as the overall dimensions of the chute is governed by space requirements, conveyor system layouts/dimensions or other restrictions which usually vary from one installation to another.

The dimensions of chute segments of the above-mentioned types are often rather large, the width of a chute segment being up to 2 m or more, the surface area part of a chute segment being 3 m² or more. Thus, a chute segment made from, e.g., steel, is rather heavy, the weight of such a chute segment being up to 80 kg or more. Consequently, installation of chute segments is troublesome and may cause lingering diseases to personnel carrying out the installation due to overload of, e.g., the personnel's back.

The strength requirements of such a chute segment are normally determined by the self- weight of the chute segment as well as by the weight of personnel operating on the chute, e.g., during installation or repair, whereas the weight of articles being conveyed along the chute is usually of minor importance in this regard. Therefore, the chute segments in a chute have to be made from a material which is sufficiently strong to carry personnel and sufficiently strong to carry their own weight. Thus, chute segments or chutes have so far been made from steel, fibre glass or plywood.

In order to control frictional surface characteristics of chute segments, coatings or layers made from a material other than the material of which the remaining parts of the chute segment are made may be applied to one or more surfaces of the chute segments. Additional coatings or layers are sometimes applied in order to reduce the level of noise generated when articles are being conveyed along the chute.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a light-weight chute segment for a chute, such as a helicoid chute, which is built up of a plurality of chute segments, the chute segments being easily joined together to form a complete chute, it is a further object of the present invention to provide a chute segment which is cheap and easy to manufacture, which is easy to handle, and which has a tensile strength allowing the chute to carry personnel which installs or repairs the chute on location or personnel which adds effects, such as cables for, e.g., photo cells to the chute.

As it has been found that at least those prior art chutes which are made from steel and fibreglass tend to generate considerable noise when articles are conveyed along the chutes, it is a further object of the present invention to provide a chute and a chute segment generating a minimum of noise when articles are conveyed along the chute while allowing the articles to be conveyed in a smooth manner even without special coatings or layers being applied to the chute.

A still further object of the present invention is to provide a method of manufacturing a chute segment according to the invention in an efficient way. A further object of the present invention is to provide a method of joining together two or more chute segments according to the invention in an easy and simple manner requiring a minimum amount of labour work while ensuring a firm interconnection between chute segments.

The present invention provides a chute segment for a chute which is built up of a plurality of chute segments, and on which chute articles may be conveyed along a conveying path defined by surface parts of the chute segments, at least a major part of the domain or domains of the chute segment which provides/provide the surface part or parts defining the contribution to the conveying path by the chute segment being made as a shell part having an outer shell which is made from a plastics or composite material and which defines one or more inner cavities, the chute segment defining an upstream and a downstream end, the downstream end being adapted to be joined with the upstream end of a downstream chute segment, and the upstream end being adapted to be joined with the downstream end of an upstream chute segment.

Where in the present context, the term "upstream" is used, this term should be interpreted as any location along the conveying path provided by the chute reached by a conveyed article before reaching a particular position, i.e. any position located prior to that particular position when seen in the conveying direction of articles. Equivalent^, where in the present context, the term "downstream" is used, this term should be interpreted as any location along the conveying path provided by the chute reached by a conveyed article after having passed a particular position, i.e. any position located subsequent to that particular position when seen in the conveying direction of articles. In the present context, the term "shell part" designates a part which is substantially hollow, i.e. a part having an outer shell and defining one or more inner cavities. In such a part, a substantial portion of the volume occupied by the part is occupied by the one or more cavities. Thus, at least 5% of the volume occupied by the shell part is occupied by the one or more inner cavities, such as at least 10% or 10-20%, such as 15-17% or more, such as at least 20% or at least 30%, such as at least 40%, in some cases at least 50% or at least 60%, such as at least 70% or at least 75% such as at least 80%, such as at least 90%.

A chute segment according to the invention has several major advantages: It is easy and cheap to manufacture, its weight is considerably reduced as compared to the weight of chute segments of equal size made from, e.g., steel or plywood. Moreover, due to one or more inner cavities, a chute segment according to the invention may be made using less material than solid chutes. Due to the reduced weight of the chute segment, assembling of two or more chute segments is easily carried out. Moreover, plastics or composite materials which are easy to shape or process, e.g., by drilling or cutting, may be used, thereby allowing for easy and fast assembling of the chute segments and for improved adaptability at a given installation which is useful, e.g., in case external appliances, such as photo detectors or grooves for electrical wires, are to be added to the chute. Furthermore, plastics or composite materials fulfilling desired surface and/or damping characteristics may be used, thereby eliminating or at least reducing the need for surface coatings or layers for obtaining such characteristics. A further advantage of the chute segment according to the invention is that it may be made from a non-corrosive material, thereby eliminating the need for providing an anti-corrosive coating or paint. Moreover, sharp edges or burrs may be avoided, thereby eliminating or at least reducing the risk of personnel being injured, e.g., when installing or repairing the chute and the risk of articles being damaged due to such sharp edges or burrs when being conveyed along the conveyor path of the chute.

The conveying path of the chute is preferably a surface which is inclined in the conveying direction and upon which articles may be conveyed due to the gravitational force. Each chute segment provides a contribution to the conveying path which contribution is defined by one or more surface parts of each chute segment. The conveying path may be bounded by, e.g, walls which may prevent the articles being conveyed from leaving the conveying path. Alternatively, the surface of the conveying path may provide friction characteristics which vary across and/or along the conveying path. A further possibility is that the contribution to the conveying path by the chute segment is upwardly inclined in an outwardly radial direction, and/or partly concave, whereby articles may be prevented from leaving the conveying path in the outwardly radial direction.

The upstream and the downstream ends defined by the chute segment are preferably a part of the outer shell. They may be surface parts of the outer shell or they may be flanges which are integrated parts of the outer shell. They may, however, also be separate parts and may thus be made from a different material, such as, e.g., stainless steel or another suitable metal or alloy, or any other material different from the material of the outer shell.

Preferably, at least the shell part of the chute segment is made from a plastics material, e.g. a polymer, such as polyethylene, or nylon, in which case the chute segment may be manufactured by moulding, such as rotational moulding. Compared to fibreglass, such materials have the advantage of being recyclable and non-toxic which is an advantage for people handling the chute segment, e.g. during manufacturing or installation, and the use of such materials makes it possible to discard a chute segment in an environmental-friendly way. Moreover, it is rather easy and cheap to dye such materials which may constitue an advantage when the chute is to be installed, e.g., next to a sorting system. In that case, different groups chutes installed, e.g., at different domains of the sorting system may be coloured in a certain way, whereby the different domains of the sorting system can be easily identified. Moreover, the use of plastics materials allows for an automated, cheap and easy manufacturing process. The use of a non-metallic material for the outer shell has the further advantage, that such a material is usually rustproof. Moreover, for many applications, no surface coating is needed whereby problems and expenses in the manufacturing process of the chute segment and wear problems resulting from a coating being worn down are eliminated. Thus, changes in surface characteristics of the conveying path and resulting problems in the conveyance of articles are avoided or reduced. For example, it has been found that wet articles tend to stick to the surface of a steel chute coated with, e.g., a Krautol layer when that layer is partly or completely worn down.

A major part of the volume of the chute segment is preferably provided by the one or more inner cavities. One or more of the one or more inner cavities may optionally be at least partly filled by a filling material which is different from the material of the outer shell. Thus, for example 10% of the one or more inner cavities may be filled in order to improve the stiffness and the stability of the chute segment. The filling material may consist of or comprise a polymer, such as polyurethane or polyethylene, preferably in the form of a foam. Polyurethane and polyethylene have the particular advantage of being recyclable. As an alternatively to or as a supplement to the filling material, the one or more inner cavities may be provided with a honeycomb structure made from one or more of the above- mentioned filling materials or from a metal, such a steel or aluminium. Such a honeycomb structure has the effect stiffen and/or stabilising the chute segment.

In the case where the filling material comprises polyurethane foam and the outer shell is manufactured by rotational moulding, the filling material may advantageously be introduced in at least one of the one or more inner cavities through a hole or bore in the outer shell after having cooled the chute segment.

In the case where the filling material comprises polyethylene foam and the outer shell is manufactured by rotational moulding, the filling material may advantageously be introduced in at least one of the one or more inner cavities during the rotational moulding process.

Preferably, the chute segment is adapted to be joined with a substantially identical chute segment, so as to build up a chute having a substantially helicoid shape. Thereby the chute defines a center axis. The surface part of the chute segment defining the contribution to the conveying path by the chute segment may define an inner and an outer peripheral edge.

In case the chute segment is adapted to be part of a substantially helicoid chute, the shape of the chute segment may be a segment of a substantially circular disc, so that the inner and/or the outer periphery of the chute has a regularly rounded shape. The surface part of the chute segment defining the contribution to the conveying path by the chute segment is preferably inclined from its upstream end downwardly towards its downstream end, so that articles may be conveyed by the gravitational force.

Preferably, the linear distance between the inner peripheral edge and the outer peripheral edge along the upstream end of the chute segment is greater than or equal to the linear distance between the inner peripheral edge and the outer peripheral edge along the downstream end of the chute segment. In this case it is possible to arrange two chute segments arranged next to each other in a chute in such a way that downstream peripheral edges are avoided at the interconnection between the two chute segments. This may be achieved when the two chute segments are arranged so that, at the interconnection between the two chute segments, the inner peripheral point on the downstream end of the upstream chute segment is arranged at a greater distance from the center axis than the inner peripheral point on the upstream end of the downstream chute segment. Analogously, the outer peripheral point on the downstream end of the upstream chute segment is arranged at a smaller distance from the center axis than the outer peripheral point on the upstream end of the downstream chute segment.

The linear distances between the inner and the outer peripheral edges along the upstream and downstream ends, respectively, are preferably between 800 and 1600 mm, such as between 1000 and 1400 mm, such as approximately 1200 mm, the distance along the upstream end being only slightly greater than the distance along the downstream end.

The chute segment may comprise a wall projecting from the surface part or parts defining the contribution to the conveying path by the chute segment and extending along the outer peripheral edge from the downstream end to the upstream end. The wall may provide the outer peripheral edge. In this case, the angle between the wall and the contribution to the conveying path by the chute segment may be approximately 90°.

A wall as described above may prevent articles being conveyed along the conveying path from leaving the conveying path in a radial direction. The wall may be solid or hollow, and it may extend along part of the length of the outer peripheral edge or along the entire length of the outer peripheral edge. The wall may be, e.g., provided with holes or cutouts. The height of the wall may be adapted to the kind of articles being conveyed. Thus, relatively flat articles, such as compact discs, video cassettes or books may not require as high a wall as larger articles, such as luggage or larger parcels.

The wall preferably defines upstream and downstream end surfaces and an upper surface. Preferably, the upstream and downstream end surfaces are aligned with the upstream and downstream ends, respectively. In this embodiment there will be no gap in the wall corresponding to the interconnection between two adjacent chute segments. This efficiently prevents the articles from leaving the conveying path in a radial direction regardless of the size of the articles. This may be useful, e.g., if articles of variable size are to be conveyed. In an embodiment wherein a wall is provided on the chute segment, a groove or bore adapted to receive one or more wires and/or tubes and/or other appropriate appliances and extending from the downstream to the upstream end surface may be provided in the wall. Such a groove or bore may be located at any suitable position on or in the wall. Thus, a bore may be, e.g, drilled in the wall. Additionally or alternatively a groove may be provided in any surface of the wall, such as the upper surface or a lower surface or an outer surface. The groove may have a removable cover so that the one or more wires and/or tubes and/or other appropriate appliances are not exposed when the chute is in use, and so that it is easy to gain access to them in case they need maintenance or replacement and/or if additional appliances are to be applied.

Appropriate appliances may be wires for, e.g., photo cells or surveillance cameras or light bulbs or any other electrical appliances which may be desired in connection with the chute. Such appliances may further be tubes, e.g., water tubes for water cooling of, e.g., wires carrying large currents or oil tubes for carrying oil for, e.g., hydraulics or air tubes for, e.g., pneumatics.

The dimensions of the bore or groove are preferably adapted so that they allow appropriate appliances to be received in the bore or groove. Thus, the dimensions may be individually suited for different purposes, such as for different kinds of appliances and for different amounts of appliances.

Preferably, a groove is provided in the upper surface, and in this case the groove preferably has a width between 34 and 42 mm, such as between 36 and 40 mm, such as approximately 38 mm.

The wall is integral with the shell, and it is preferably made from the same material as the shell. The mould for the rotational moulding process may thus be shaped in such a way that the wall and the shell are moulded in one step, thus providing a strong interconnection between the shell and the wall and a rigid construction. The wall may, however, alternatively be applied to the shell by, e.g., gluing or bolting or by any other appropriate method of assembling in which cases the wall may be made from any material, including the material from which the shell part is made and other materials, such as steel or fibre glass. Alternatively or additionally the wall and the remaining parts of the chute segment may be fixed in relation to each other and/or in relation to one or more other chute segments in a chute by means of a wire which is subjected to stress and which is locked at both ends.

In case the chute segment is adapted for a chute having a substantially helicoid shape, the chute segment preferably spans over an angle which is smaller than or equal to 90°, such as between 30^° and 90^°, such as between 30^° and 80^°, such as approximately 60^°, approximately 70^° or approximately 45^°.

The chute may segment further comprise a holding member which is connected to the chute segment at the inner peripheral edge. In this embodiment the chute is preferably connected to a column coextending with the center axis, the holding member being preferably adapted to fix the chute segment in relation to the column in a transverse direction in relation thereto.

The holding member may be integral with the shell, the holding member being made from the same material as the shell. If the chute segment is manufactured by rotational moulding, the mould may thus be shaped in such a way that the chute segment and the holding member are moulded in one step.

Preferably, the holding member defines a through-going bore or cavity for receiving at least a portion of the column. The cross-section of the through-going bore or cavity may be of any shape, such as a substantially cylindrical shape or a substantially square, rectangular or triangular shape or a star-like shape or any other suitable shape. The shape and the dimensions of the through-going bore or cavity are preferably adapted to the shape and the dimensions of the column, so that the column may extend through the bore or cavity, or so that the column may be partly received in the bore or cavity. The diagonal or diameter is preferably between 100 and 300 mm, such as between 150 and 250 mm, such as approximately 200 mm or 160-180 mm.

The dimensions of the holding member are preferably adapted to the dimensions of the chute member in the area near the inner peripheral edge as well as to the dimensions of the column. Preferably, for a 45° chute segment, the height of the holding member is between 100 and 300 mm, such as between 150 and 250 mm, such as approximately 200 mm. The holding member may be fortified by a sleeve extending through the through-going bore or cavity. The sleeve preferably has a shape which corresponds to the shape of the through-going bore or cavity, so that the sleeve may be fitted relatively tightly into the through-going bore or cavity.

The sleeve may have a free end surface at its one end and a collar portion at its other end, said collar portion having: an annular abutting surface adapted to be received in a recess in an end surface of said holding member, and a free collar end surface constituting a substantially common end surface together with an end surface of the holding member and being adapted to support the free end surface of the sleeve provided in the through-going bore or cavity of an upstream or downstream chute segment.

Preferably, the sleeve is at least partly made from a metal or an alloy, such as stainless steel. When two chute segments according to the invention are positioned adjacent to each other and connected to a center column in such a way that the holding member of one of the chute segments rests upon the holding member of the other chute segment, the collar portion of one of the chute segments will abut the free end surface of the other chute segment. This allows for a metal-to-metal connection even if one of the chute segments is slightly displaced in a radial direction in relation to the other chute segment. It further ensures that the forces on the lower-most chute segment due to the gravitational pull on the upper-most chute segment are expediently distributed in the chute segment. Thereby the force per area unit is reduced, whereby the chute segment material is subjected to minimum stress.

In an embodiment where the chute segment is adapted to form part of a chute having a substantially helicoid shape, the distance in the center axis direction - which is usually a substantially vertical direction - between the upstream and the downstream points of the inner peripheral edge is preferably substantially the same as the distance in the center axis direction between the upstream and the downstream points of the outer peripheral edge. In embodiments where the chute segment spans over approximately 45°, the distance is preferably between 100 and 300 mm, such as between 150 and 250 mm, such as approximately 200 mm. Preferably, at least a substantial part of the shell is made from polyethylene. At least a substantial part of the shell may be made from an antistatic material or from another material having an antistatic additive comprised therein. Such an antistatic additive may, e.g., comprise carbon particles. An example of such a material comprising an antistatic additive is Microstat ML which is manufactured by Micropol Ltd.

In case the chute segment has the dimensions given above as examples of dimensions, the total volume of the chute segment is typically between 0.05 and 0.10 m³, the total weight of the chute segment being between 14 and 18 kg, such as between 15 and 17 kg, such as approximately 16 kg, the total volume of the chute segment being defined as the sum of the volume of the one or more inner cavities and the solid material volume of all parts of the chute segment. For comparison, a chute segment of corresponding dimensions made from steel would have a weight of approximately 35-45 kg.

In case the chute segment has a total volume of approximately 0.08 m³, the total weight of the chute segment is preferably between 14 and 18 kg, such as between 15 and 17 kg, such as approximately 16 kg. The ratio between the solid material volume and the total volume of the chute segment is preferably 0.05 - 0.9, such as 0.08 - 0.8 or 0.1 - 0.75 or 0.1 - 0.7 or 0.1 - 0.6 or 0.1 - 0.5 or 0.1 - 0.4 or 0.1 - 0.3 or 0.1 - 0.25 or 0.1 - 0.2, such as approximately 0.15 - 0.17.

Preferably, the thickness of material of the shell is between 3 and 6 mm, such as between 4 and 5.5 mm, such as approximately 5 mm.

The chute segment may further be fortified by one or more ribs which extend along one or more inner surfaces of the shell, whereby the contribution to the conveying path by the chute segment is additionally supported/fortified. Such ribs may be created during the rotational moulding process. Preferably, at least one of the ribs provides an interconnection between opposite inner surface parts of the shell. The ribs are preferably provided by shaping the mould which is used for the rotational moulding process in such a way that the distance between opposite inner walls of the mould is relatively small at certain points. Thus, during the rotational moulding process when the inner walls of the mould are coated with the shell material, the shell material will form interconnections, so-called "kiss points", between the shell parts corresponding to the aforementioned points on the inner walls of the mould.

One or more holes may be provided in the upstream end and in the downstream end of the chute segment, the holes corresponding in pairs to each other in such a way that two chute segments may be joined together by applying joining means to each of the pairs of holes when the chute segments are arranged next to each other in such a way that the upstream end of a first one of said chute segments abuts the downstream end of a second one of said chute segments.

The joining means may be bolts or screws or rivets or pieces of wire or any other suitable kind of joining means.

Each of the one or more holes may have an elongated, non-circular shape. Each hole in the upstream end of the chute segment may be elongated in a first direction which is substantially perpendicular to a second direction in which the corresponding hole in the downstream end of the chute segment may be elongated.

The upstream and downstream ends of the chute segment may be fortified by applying a bushing to each of the one or more holes provided in the upstream and downstream ends, respectively.

The present invention further provides a method of manufacturing a chute segment according to the invention and comprising the step of manufacturing at least the shell by rotational moulding. The rotational moulding process is known perse to those skilled in the art of moulding polymers. US 5,358,682 and US 5,641 ,439 disclose certain kinds of rotational moulding processes and apparatuses therefor.

When the chute segment to be manufactured by the method comprises a holding member as previously defined, which holding member is provided with a sleeve as previously defined, the method may comprise inserting the sleeve into the bore or cavity defined by the holding member substantially immediately after the rotational moulding step and before the chute segment is cooled. When the chute segment to be manufactured by the method is provided with one or more bushings as previously defined, the method may comprise inserting the one or more bushings into the holes provided therefor substantially immediately after the rotational moulding step and before the chute segment is cooled.

The present invention further provides a method of joining two or more chute segments according to the invention, said method comprising the steps of: providing one or more holes in the upstream end and one or more holes in the downstream end, respectively, of each of the chute segments to be joined, said holes corresponding in pairs to each other so that two chute segments may be joined together by applying joining means to each of the pairs of holes when said chute segments are arranged next to each other in such a way that the upstream end of a first one of said chute segments abuts the downstream end of a second one of said chute segments; - fortifying the upstream and downstream ends by providing a bushing to each of the one or more holes in the upstream end and each of the one or more holes in the downstream end of each chute segment; arranging the chute segments next to each other in such a way that the upstream end of one chute segment abuts the downstream end of another chute segment, and in such a way that the holes corresponding in pairs are positioned next to each other; and applying joining means to the one or more pairs of holes.

The joining means preferably comprises one or more bolts, and the method preferably comprises the step of bolting together two or more chute segments.

In an embodiment, wherein the chute is connected to a column coextending with its center axis, and wherein a holding member is connected to each chute segment at the inner peripheral edge, so as to fix the chute segment in relation to the column in a transverse direction in relation to the column, the method of joining two or more chute segments according to the invention may comprise the step of coaxially arranging the holding members of the two or more chute segments to be joined next to each other along the column. The present invention further relates to a chute comprising at least two chute segments according to the invention.

The chute may have a substantially helicoid shape, it may be straight, or it may be of any other shape/configuration.

The chute according to the invention is particularly suited for conveying articles from one level of a conveyor system to another (lower) level of the conveyor system due to the gravitational force. A chute having a substantially helicoid shape is preferred in conveyor system where articles need to be conveyed from a higher to a lower level while being conveyed only a small distance in a substantially horizontal direction, thus requiring a large angle of inclination if the articles are to be conveyed by a straight chute.

Preferably, the at least two chute segments are manufactured by a method according to the invention and have been joined by a method according to the invention.

Each chute may be connected to a column coextending with the center axis, and a holding member may be connected to the chute segment at the inner peripheral edge, so as to fix the chute segment in relation to the column in a transverse direction in relation to the column.

The invention will now be further described with reference to the drawings in which:

Fig. 1 is a perspective elevated view of a chute segment according to the present invention, as seen from the outer peripheral edge,

Fig. 2 is a perspective view of the chute segment of Fig. 1 , as seen from the outer peripheral edge and partly from below,

Fig. 3 is a view from below of the chute segment of Fig. 1 along the line A indicated in Fig. 2,

Fig. 4 is a perspective view of the chute segment of Fig. 1 , as seen from the outer peripheral edge and partly from above, Fig. 5 is an elevated view of the chute segment of Fig. 1 ,

Fig. 6 is a side view of a sleeve for fortifying the holding member of a chute segment, and

Fig. 7 is an elevated view of the sleeve of Fig. 6,

Fig. 8 illustrates a conveyor system comprising a chute according to the invention.

Figs. 1-5 show a chute segment 9 according to the present invention. The chute segment 9 defines a conveying path contribution or conveying path 10, the conveying path 10 defining an inner peripheral edge 11 and an outer peripheral edge 12 which limit the conveying path along which articles are forced to move when being conveyed along a chute built up of a number of chute segments 9. The conveying path 10 is inclined, so as to allow the articles to be conveyed by the gravitational force. The chute segment 9 further comprises an upstream end 13 and a downstream end 14. In Figs. 1 , 3 and 5 a holding member 15 connected to the inner peripheral edge 11 is further shown. The holding member 15 defines a through-going bore 16 which is adapted for receiving a part of the center column of the chute. At the bottom end surface 15a of the holding member 15 and along the through-going bore 16 a recess 17 is provided. The recess 17 is adapted to receive a collar portion 18 of a sleeve 19 which may be applied to the through-going bore 16 in order to fortify the holding member 15. The sleeve 19 is shown in detail in Figs. 6 and 7. The sleeve 19 is preferably made from a metal, most preferably steel.

The chute segment 9 is preferably manufactured by rotational moulding. A sleeve 19, e.g., as the one shown in Figs. 6 and 7, is applied to the through-going bore 16 before the chute segment 9 is cooled in order to fortify the holding member 15. The sleeve 19 is applied in such a way that the collar portion 18 is received in the recess 17 which is provided at the end surface of the holding member 15 around the through-going bore 16, and in such a way that the free collar end surface 20 constitutes a substantially common surface with the bottom end surface 15a of the holding member 15 and the free end surface 21 constitutes a substantially common surface with the top end surface 15b of the holding member 15. When the chute segment 9 is cooled it will "shrink" around the sleeve 19, which is thereby being integrated in the chute segment 9. When the chute is assembled, two chute segments 9 are arranged next to each other in such a way that the two holding members 15, having been fortified by a sleeve 19 as described above, are arranged co-axially, one above the other, on a center column in such a way that the free collar end surface 20 of the sleeve 19, which has been applied to the upper chute segment 9, abuts the free end surface 21 of the sleeve 19, which has been applied to the lower chute segment 9. Thus a substantially metal-metal connection between the two holding members occur, thereby fortifying the chute. The collar portion 18 of the sleeve 19 provides the metal-to-metal connection even if one of the chute segments 9 is slightly displaced as compared to the other chute segment 9. It further allows for the load capacity to be distributed into the material of the holding member 15, thus providing a stronger construction of the chute.

When the two chute segments 9 have been arranged as described above, the downstream end 14 of the upper chute segment 9 abuts the upstream end 13 of the lower chute segment 9. The two chute segments 9 may then be joined together by applying joining means, e.g., bolts or screws to holes 22, 23, which are provided in the upstream 13 and downstream 14 ends, respectively. The holes 22, 23 are provided in such a way, that a hole 22 provided in the upstream end 13 of the lower chute segment 9 is arranged corresponding to the hole 23 provided in the downstream end 14 of the upper chute segment 9.

Preferably, the holes 22 provided in the upstream end 13 are elongated in a direction which is substantially perpendicular to a direction in which of the holes 23 provided in the downstream end 14 are elongated. In Figs. 1 , 2 and 4 the holes 22 provided in the upstream end 13 are elongated in a substantially vertical direction, while the holes 23 provided in the downstream end 14 are elongated in a substantially horizontal direction.

Preferably, the upstream 13 and downstream 14 ends are fortified by applying a bushing to each of the holes 22, 23. The bushing is preferably made from metal, most preferably steel, and it is preferably introduced in the holes 22, 23 in a similar way as the one described for applying the sleeve 19 to the holding member 15. This provides a strong joint between the two chute segments 9.

The chute segments 9 are manufactured in such a way that the distance between the inner 11 and the outer 12 peripheral edges along the upstream end 13 is greater than the corresponding distance along the downstream end 14, and the outer peripheral edge 12 provides a smooth connection between the two ends 13, 14. When two chute segments 9 are joined as described, the downstream end 14 of the upper chute segment 9 will "fit" on the inside of the upstream end 13 of the lower chute segment 9. Thus, when the articles to be conveyed by the chute pass the interconnection between the two chute segments 9, they will experience no obstructions in the outer peripheral edge. Instead the outer peripheral edge 12 of the upper chute segment 9 will smoothly lead the articles past the interconnection.

The outer peripheral edge 12 of the chute segment 9 comprises a groove 24 which is suitable for receiving, e.g., cables for electrical installations which may be used in connection with the chute, such as photo cells, cameras, light bulbs etc.

Since the distance to be travelled by the articles or the part of the articles being near the outer peripheral edge 12 of the chute segment 9 is greater than the equivalent distance near the inner peripheral edge 11 when an article is passing a chute segment 9, the angle of inclination of the conveying path 10 is not uniform across the chute segment 9. Instead the whole of the upstream end 13 is contained in a substantially horizontal plane, and the entire downstream end 14 is contained in another substantially horizontal plane. Thus, the articles or the part of the articles being conveyed near the outer peripheral edge 12 and the articles or the part of the articles being conveyed near the inner peripheral edge 11 are conveyed the same distance in a vertical direction when passing a chute segment 9.

Fig. 8 illustrates a conveyor system comprising a chute 25 according to the invention, the chute 25 being built up of a number of chute segments 9 according to the invention. The conveyor system may comprise conveyor wagons 26 for moving along tracks, the conveyor wagons 26 carrying items to be sorted and/or transported, such as suitcases, mail bags, postage packages etc. The conveyor wagons 26 may be loaded with items at one or more loading stations arranged along the track, and items may be unloaded at one or more unloading station arranged along the track. The unloading stations may comprise a chute 25 according to the invention, wherein items are moved due to the gravitational force.

The chute 25 illustrated in Fig. 8 has a substantially helicoid shape thereby defining a center axis along which a center column 27 extends. The chute 25 of Fig. 8 is suited for conveying articles from one level 28 of the conveyor system to another lower level 29 of the conveyor system. As it appears from Fig. 8, the level difference between the two levels 28, 29 and the space available in a substantially horizontal direction may sometimes require a large angle of inclination of the chute 25 if articles are to be conveyed from the higher level 28 to the lower level 29 by a chute having only a straight portion. Thus, the velocity of articles being conveyed may become so high that there is a risk of damaging the articles. A helicoid chute 25 as the one shown in Fig. 8 allows for a reduction of the angle of inclination without the chute 25 taking up more space in a substantially horizontal direction. The velocity of the articles may thus be controlled and damage on the articles due to high velocity may be avoided or at least reduced to a minimum.

Claims

1. A chute segment for a chute which is built up of a plurality of chute segments, and on which chute articles may be conveyed along a conveying path defined by surface parts of the chute segments, at least a major part of the domain or domains of the chute segment which provides/provide the surface part or parts defining the contribution to the conveying path by the chute segment being made as a shell part having an outer shell which is made from a plastics or composite material and which defines one or more inner cavities, the chute segment defining an upstream and a downstream end, the downstream end being adapted to be joined with the upstream end of a downstream chute segment, and the upstream end being adapted to be joined with the downstream end of an upstream chute segment.

2. A chute segment according to claim 1 , at least the shell part of which is manufactured by rotational moulding.

3. A chute segment according to claim 1 or 2, wherein at least one of the one or more inner cavities is at least partly filled by a filling material which is different from the material of the outer shell.

4. A chute segment according to claim 3, wherein the filling material is a polymer.

5. A chute segment according to claim 4, wherein the filling material is in the form of a foam.

6. A chute segment according to any of claims 1 to 5, adapted for a chute having a substantially helicoid shape, the chute thereby defining a center axis, the surface part of the chute segment defining the contribution to the conveying path by the chute segment defining an inner and an outer peripheral edge.

7. A chute segment according to claim 6, wherein the linear distance between the inner peripheral edge and the outer peripheral edge along the upstream end of the chute segment is greater than or equal to the linear distance between the inner peripheral edge and the outer peripheral edge along the downstream end of the chute segment, so as to avoid downstream peripheral edges at the interconnection between two substantially identical chute segments arranged next to each other in said chute.

8. A chute segment according to claim 6 or 7, further comprising a wall projecting from the surface part or parts defining the contribution to the conveying path by the chute segment and extending along the outer peripheral edge from the downstream end to the upstream end, so as to prevent articles being conveyed along the conveying path from leaving the conveying path in a radial direction, the wall defining upstream and downstream end surfaces and an upper surface.

9. A chute segment according to claim 8, wherein the upstream and downstream end surfaces are aligned with the upstream and downstream ends, respectively.

10. A chute segment according to claim 8 or 9, wherein a groove or bore adapted to receive one or more wires and/or tubes and/or other appropriate appliances and extending from the downstream to the upstream end surface is provided in the wall.

11. A chute segment according to claim 10, wherein the groove or bore is provided in the upper surface.

12. A chute segment according to any of claims 8 to 11 , wherein the wall is integral with the shell, the wall being made from the same material as the shell.

13. A chute segment according to any of claims 6 to 12, wherein the chute segment spans over an angle which is smaller than or equal to 90┬░.

14. A chute segment according to claim 13, wherein the chute segment spans over an angle which is between 30┬░ and 90┬░.

15. A chute segment according to claim 14, wherein the chute segment spans over an angle which is between 30┬░ and 60┬░.

16. A chute segment according to claim 15, wherein the chute segment spans over an angle which is approximately 45┬░.

17. A chute segment according to any of claims 3 to 16, further comprising a holding member which is connected to the chute segment at the inner peripheral edge, the chute being connected to a column coextending with the center axis, the holding member being adapted to fix the chute segment in relation to the column in a transverse direction in

5 relation thereto.

18. A chute segment according to claim 17, wherein the holding member is integral with the shell, the holding member being made from the same material as the shell.

10 19. A chute segment according to claim 17 or 18, wherein the holding member defines a through-going bore or cavity for receiving at least a portion of the column.

20. A chute segment according to claim 19, wherein the holding member is fortified by a sleeve extending through said through-going bore or cavity.

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21. A chute segment according to claim 20, wherein the sleeve has a free end surface at its one end and a collar portion at its other end, said collar portion having: an annular abutting surface adapted to be received in a recess in an end surface of said holding member, and 20 - a free collar end surface constituting a substantially common end surface together with an end surface of the holding member and being adapted to support the free end surface of the sleeve provided in the through-going bore or cavity of an upstream or downstream chute segment.

25 22. A chute segment according to any of claims 6 to 21 , wherein the distance in the center axis direction between the upstream and the downstream points of the inner peripheral edge is substantially the same as the distance in the center axis direction between the upstream and the downstream points of the outer peripheral edge.

30 23. A chute segment according to any of the preceding claims, wherein at least a substantial part of the shell is made from polyethylene.

24. A chute segment according to any of the preceding claims, in which at least a substantial part of the shell is made from an antistatic material or from another material 35 having an antistatic additive comprised therein.

25. A chute segment according to claim 24, wherein the antistatic additive comprises carbon particles.

26. A chute segment according to any of the preceding claims, having a total volume between 0.05 and 0.10 m³, the total weight of said chute segment being between 14 and 18 kg.

27. A chute segment according to claim 26, having a total volume of approximately 0.08 m³, the total weight of said chute segment being approximately 16 kg.

28. A chute segment according to any of claims 2 to 27, which chute segment is further fortified by one or more ribs which extend along one or more inner surfaces of the shell and which are created during the rotational moulding process.

29. A chute segment according to claim 28, wherein at least one of said ribs provides an interconnection between opposite inner surface parts of the shell.

30. A chute segment according to any of the preceding claims, wherein one or more holes are provided in the upstream end and in the downstream end of the chute segment, said holes corresponding in pairs to each other in such a way that two chute segments may be joined together by applying joining means to each of the pairs of holes when said chute segments are arranged next to each other in such a way that the upstream end of a first one of said chute segments abuts the downstream end of a second one of said chute segments.

31. A chute segment according to claim 30, wherein each of the one or more holes has an elongated, non-circular shape, each hole in the upstream end of the chute segment being elongated in a first direction which is substantially perpendicular to a second direction in which the corresponding hole in the downstream end of the chute segment is elongated.

32. A chute segment according to claim 30 or 31 , wherein the upstream and downstream ends of the chute segment are fortified by applying a bushing to each of the one or more holes provided in the upstream and downstream ends, respectively.

33. A method of manufacturing a chute segment according to any of claims 1 to 32 and comprising the step of manufacturing at least the shell by rotational moulding.

34. A method according to claim 33, wherein the chute segment comprises a holding

5 member as defined in claim 17, which holding member is provided with a sleeve as defined in claim 20, the method comprising inserting the sleeve into the bore or cavity defined by the holding member substantially immediately after the rotational moulding step and before the chute segment is cooled.

10 35. A method according to claim 33 or 34, wherein the chute segment is provided with one or more bushings as defined in claim 32, the method comprising inserting the one or more bushings into the holes provided therefor substantially immediately after the rotational moulding step and before the chute segment is cooled.

1 5 36. A method of joining two or more chute segments according to any of claims 1 to 32, said method comprising the steps of: providing one or more holes in the upstream end and one or more holes in the downstream end, respectively, of each of the chute segments to be joined, said holes corresponding in pairs to each other so that two chute segments may be joined

20 together by applying joining means to each of the pairs of holes when said chute segments are arranged next to each other in such a way that the upstream end of a first one of said chute segments abuts the downstream end of a second one of said chute segments; fortifying the upstream and downstream ends by providing a bushing to each of the

25 one or more holes in the upstream end and each of the one or more holes in the downstream end of each chute segment; arranging the chute segments next to each other in such a way that the upstream end of one chute segment abuts the downstream end of another chute segment, and in such a way that the holes corresponding in pairs are positioned next to each other;

30 and applying joining means to the one or more pairs of holes.

37. A method according to claim 36, wherein the joining means comprise one or more bolts, and wherein said method comprises the step of bolting together two chute segments. 35

38. A method according to claim 36 or 37, wherein the chute is connected to a column coextending with its center axis, and wherein a holding member is connected to each chute segment at the inner peripheral edge, so as to fix the chute segment in relation to the column in a transverse direction in relation to the column, said method comprising the step

5 of coaxially arranging the holding members of the two or more chute segments to be joined next to each other along the column.

39. A chute comprising at least two chute segments according to any of claims 1 to 32.

10 40. A chute according to claim 39, wherein the at least two chute segments are manufactured by a method according to any of claims 33 to 35.

41. A chute according to claim 39 or 40, wherein the at least two chute segments have been joined by a method according to any of claims 36 to 38.

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42. A chute according to any of claims 39 to 41 , wherein each chute is connected to a column coextending with the center axis, and wherein a holding member is connected to the chute segment at the inner peripheral edge, so as to fix the chute segment in relation to the column in a transverse direction in relation to the column.

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