Conveyor for conveying bulk material

Abstract: A conveyor for conveying bulk material includes a conveyor loop (2) having an upper section forming a transport deck (5) extending along a transport path and a lower return section. The conveyor loop (2) includes an array of pins (7) and connections (8, 9) interconnecting the pins (7) and an array of carrier beams (10) each extending transverse to the array of pins (7) and connections (8, 9). A side barrier (11) above and along a side of the transport deck (5) for restraining bulk material from moving laterally off the is formed by an array of side barrier plates (24; 124). The side barrier plates (24; 124) are each fixedly connected relative to axes (35) of a pair of the pins (7). Leading and trailing ends (36) of successive side barrier plates (24; 124) are in at least close proximity of each other.

Description: TECHNICAL FIELD AND BACKGROUND OF THE INVENTION In conveyors for transporting bulk material generally provisions are made to keep bulk material on the transport deck, such as waste paper and cardboard, plastic or glass to be recycled, from falling over the side of the transport deck. In US-A-3 866 743 a belt conveyor according to the introductory portion of claim 1 is disclosed. In this belt conveyor the arrays of side barrier plates form side barriers along the side of the transport deck for keeping material from falling from the transport deck. Each side barrier plate consists of a forward plate and a rearward plate Ends of adjacent pairs of identical side plates overlap each other, each pin being connected to the forward and rearward portions of successive plates. Each of the side plates is formed of two flat plates. A forward one of the plates has a leading arcuate edge which is an arc of a circle having its center at the center of a forward bore. The trailing edge of the forward plate has a matching arcuate shape described as an arc of a circle of slightly larger radius and with its center at the center of a rear bore provided in the rear plate. The rear one of the plates overlaps the trailing arcuate edge of the forward plate and is spot welded thereto. Thus, when adjacent side plates are placed together the leading edge of one side plate will be closely spaced from the trailing edge of the preceding side plate. SUMMARY OF THE INVENTION It is an object of the present invention to provide a simple 1 solution for keeping material from falling over the side of conveyor. According to the present invention, this object is achieved by providing a conveyor according to claim 1. Further objects, modes, embodiments and details of the invention appear from the dependent claims and the description in which reference is made to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic representation in side view of an example of a conveyor according to the present invention; Figs. 2 is a more detailed view in cross-section along the line II-II in Fig. 1; Figs. 3 is an enlarged and more detailed view of a portion of Fig. 2; Figs. 4 is a schematic representation of the chain of the conveyor according to Figs. 1-3; Figs. 5 is a top plan view in cross-section along the line V-V in Fig. 1 of a portion of a transport deck of the conveyor according to Figs. 1-4; Figs. 6 is a partial frontal view in cross-section along the line VI-VI in Fig. 1; Fig. 7 is a partial side view in cross-section along the line VII-VII in Fig. 8; Fig. 8 is a partial frontal view in cross-section along the lines VIII-VIII in Figs. 1 and 7; Fig. 9 is a partial frontal view in cross-section along the lines IX-IX in Figs. 1 and 10; Fig. 10 is a partial side view in cross-section along the lines X-X in Fig. 9, Fig. 11 is a top plan view of a side portion of a transport deck of a conveyor according to an alternative embodiment of the present invention; and Fig. 12 is a partial side view in cross-section along the line XII-XII in Fig. 11. DETAILED DESCRIPTION The invention is first described with reference to a presently most preferred exemplary embodiment shown in Figs. 1-10. Dependent on transport requirements and operating circumstances, features such as dimensions and configuration of the transport path may vary. In various instances where the conveyor as shown includes larger numbers of mutually identical parts or portions, for the sake of clarity of the drawings, only a limited number of the parts or portions are designated by reference numerals. The chain conveyor 1 shown in Figs. 1-10 has an endless conveyor loop 2 extending over sprocket wheels 3, 4 on opposite ends of the conveyor 1. The conveyor loop 2 has a momentarily upper section 5 forming a transport deck extending along a transport path and a momentarily lower return section 6 extending under the transport deck 5. The conveyor loop 2 includes two chain arrays each composed of chain pins formed by bolts 7 transverse to the chain array and connections in the form of chain plates 8, 9 extending in longitudinal direction of the array and interconnecting the chain bolts 7. The conveyor loop 2 further includes an array of carrier beams 10 extending in a direction transverse to the array. Although it is in principle possible to provide a chain having an array of pins and chain plates on one side only - the transport deck preferably being oriented horizontally or sloping down towards the chain array when seen in cross-section - it is preferred to provide the conveyor loop with chain arrays along both lateral sides of the conveyor loop 2 and interconnected by the carrier beams 10, as in the present example to provide a stable support for the conveyor loop 2. In order to keep material which is deposited and transported on the transport deck section 5 of the conveyor loop 2 from falling over the side of the conveyor loop 2, a side barrier 11 is provided which extends above and along a side of the transport deck 5. The conveyor further includes a support structure with adjustable legs 12-15, guide rails 16, 17 for rollers 19 of the chain 2 and transverse beams 20, some of which interconnect U-shaped beams 18 of which flanges form the guide rails 16, 17 and others of which interconnect frame portions 21 (Fig. 8), 22 (Fig. 9) specifically adapted for interconnecting conveyor sections having mutually different sloping angles. The conveyor loop 2 extends through a tunnel-shaped housing 23. For driving the circulation of the conveyor loop 2, a drive unit 25 is provided which is coupled to the sprocket wheel 3 via an axis 26. A motor may be included in the drive unit 25 or power may be obtained from an external drive motor. The side barrier 11 is formed by an array of side barrier plates 24 which are each fixedly connected relative to central axes of a pair of successive ones of the bolts 7. Successive ones of the side barrier plates 24 are connected relative to successive pairs of the bolts 7 and leading and trailing ends of successive side barrier plates 24 are in close proximity of each other (distance preferably less than 10 mm and more preferably less than 1 to 5 mm) so that in operation very little or no bulk material falls over the side edges of the conveyor loop 2. If the bulk material to be transported is particularly fine grained, the end portions of successive side barrier plates 24 are preferably continuously in contact with each other. In operation, the side barrier plates 24 move along with the conveyor loop, so that friction and wear due to relative movement between contacting portions of the conveyor loop 2 or material transported thereon and the side barrier 11 is substantially reduced. Furthermore, the side barrier plates 24 do not move substantially in longitudinal direction relative to material which is being transported by the conveyor loop, so that a possible source of dislodgement of material travelling on the transport deck 5 is essentially eliminated. Compared with conveyor belts of the through type, the proposed conveyor is particularly advantageous if the transport deck has sections extending at different sloping angles. Because the side barrier 11 is composed of an array of side barrier plates 24 the position of each of the side barrier plates 24 being determined by a successive pair of the bolts 7, the side barrier 11 can easily accommodate to a great variety of curvatures to which the conveyor loop 2 is subjected in operation. This can be seen particularly clearly in Figs. 4, 7 and 10. Furthermore, because the relative movability of successive side barrier plates corresponds to the relative movability of the links of the chain the side barrier plates 24 can be made of substantially rigid material such as steel. Accordingly, a particularly robust and durable construction can be obtained. In order to avoid the formation of gaps between the side barrier plates 24 and the transport deck 5 where the direction of the conveyor loop 2 changes, such as at the sprocket wheels 3, 4 and where the sloping angle of the transport track changes, while nevertheless not substantially impeding the relative movability of the successive side barrier plates 24, the conveyor loop 2 has a material carrying surface 27 having side edges 28 facing the side barrier plates 24. This allows sections of the material carrying surface 27 between successive carrier beams 10 to move freely relative to the side barrier plates 24 over some distance transverse to a plane in which the material carrying surface 27 extends without causing the formation of a substantial gap. Surfaces 29 (see Figs. 3 and 5) of successive side barrier plates 24 facing the side edges 28 extend in a common plane, which facilitates ensuring that the material carrying surface 27 links-up closely to the side barrier plates 24 also in curved sections of the conveyor loop 2 To ensure that also small particles are effectively kept from falling from the conveyor loop 2, the side edges 28 of the material carrying surface 27 abut the side barrier plates 24. The abutment of the side edges 28 against the inner surfaces 29 of the side barrier plates is obtained in a particularly simple and reliable manner by providing that the side edges 28 of the material carrying surface 27 slightly press against the side barrier plates 24. In the present example this is achieved by providing that the material carrying surface 27 is the surface of a resilient, rubber belt 30 having a width in uncompressed state which is slightly larger than the distance between side barrier plates 24 on opposite sides of the carrier beam 10. Since the distance in transport direction between successive carrier beams is substantially smaller than the width of the transport deck, gaps between the side barrier plates 24 and the material carrying surface 27, due to sagging of the material carrying surface under the weight of the transported material, will generally not occur. However, if necessary, for instance stiffening busks and/or high modulus fiber reinforcements oriented for instance longitudinally or transversely can be incorporated in the web material 30 to counteract sagging of the material carrying surface 27. The flexible belt 30 is carried by the carrier beams 10 and mounted to the carrier beam by clamping between a strip 31, 32 and the carrier belt, the strips 31, 32 being bolted to the carrier beams 10. The strips 32 mounted to each second carrier beam 10 each have a flange 33 forming a material entrainer projecting from a foot 34 of the strip 32, the belt 30 being clamped between the foot 34 of the strip 32 and the carrier beam 10. Thus, the function of mounting the belt 30 to the carrier beams 10 and providing a projection for entraining material on the belt, for instance during the ascent along a sloping section of the transport track, are efficiently combined. In the present example, the fixed position of each of the side barrier plates 24 relative to the two axes 35 (see Fig. 3) of the associated bolts 7 is obtained in a particularly efficient manner, because the bolts 7 are directly connected to the side barrier plates 24. Accordingly, the bolts 7 fulfil both the functions of forming hinges of the respective chain array and of providing connections between the chain array and the central area of the conveyor loop 2 for carrying bulk material. In turn, the side barrier plates 24 are directly connected to opposite ends of the transverse carrier beams 10, so that the side barrier plates 24 fulfil both the function of restraining bulk material against falling off the transport deck and of connecting the transverse carrier beams 10 to the chain arrays. The bolts 7 have threaded ends threaded in threaded bores in the side barrier plates 24 allowing the chain arrays to be connected to the side barrier plates 24 in a simple manner and allowing separate replacement of both the central load carrying area of the conveyor loop 2 and the chain arrays. The bolts 7 abut end faces of the carrier beams 10 attached to the side barrier plates 24 so that the depth over which the bolts 7 can be screwed into the side barrier plates 24 is limited without the need of drilling blind holes in the side barrier plates 24 or providing specific measures to limit the depth over which the bolts 7 can be screwed into the side barrier plates 24. As can be seen particularly clearly in Figs. 4, 7 and 10, end faces 36 of the side barrier plates 24 facing each other are each curved with a radius R (Fig. 4) about axes 35 of a most adjacent one of the bolts 7 fixedly connected relative to the respective one of the side barrier plates 24. Due to this shape of the end faces 36 of the side barrier plates 24, successive side barrier plates 24 remain in the same close proximity, or in contact with each other, both during passage along a straight transport track section and when the respective portion of the conveyor loop 2 passes through a curved track portion, for instance at the end of the conveyor (see Fig. 4) or where the transition toward a different sloping angle is made (Figs. 7 and 10). To further reduce the risk of material inadvertently falling over the side of the transport deck 5, the conveyor 1 is provided with substantially stationary side guards 42 extending in longitudinal direction of the conveyor loop 2 and suspended above the transport deck on a side of the side barrier plates 24 facing away from the bolts 7 and the chain array. The carrier rollers 19 supported by guide tracks 16 and carrying the bolts 7 provide a simple construction for smoothly guiding the conveyor loop along the transport track. To laterally guide the conveyor loop 2, the conveyor further includes guide rollers 43 (see Figs. 1 and 6) mounted in stationary positions (see Fig. 1) and having circumferential surfaces 44 facing surfaces 45 of the side barrier plates 24 facing away from the carrier beams 10. Thus, the side barrier plates 24 also contribute to lateral guidance of the conveyor loop 2. Figs. 7-10 further illustrate the construction of the side plates 21, 22 which is specifically adapted for leading the conveyor loop 2 through a transition to a section of the conveyor 1 having a different sloping angle. In Figs. 7 and 8, the plate 21 carries curved upper and lower guide ridges 46-49 between which the rollers 19 are guided through the curved transitions between sections having different sloping angles. In Figs. 9 and 10, the plate 22 carries curved guide ridges 50, 51 over which the rollers 19 are run through the curved transitions between sections having different sloping angles. From the above description it will be clear to the skilled person that within the framework of the present invention, many variations based on the proposed examples are possible. The bolts 7 can for instance be connected by any suitable type of string members, such as a toothed belt or a wire instead of by chain plates as provided according to the present examples. Guidance of the chain can for instance be achieved by a series of stationary, rotatable sprocket wheels instead of, as shown, by guide rails over which rollers can pass. As is illustrated by Figs. 11 and 12, the passage of material in-between opposing end faces 36 of the side barrier plates 24 can also be counteracted in different manners, for instance by providing successive side barrier plates 124 projecting past each other and having co-operating recesses 137, 138 and projections 140, 141. Such side barrier plates of a more complex design are preferably manufactured by casting or moulding.

Claims: A conveyor for conveying bulk material comprising: a conveyor loop (2) having a momentarily upper section forming a transport deck (5) extending along a transport path and a momentarily lower return section extending under said transport deck (5), said conveyor loop (2) including at least one array of pins (7) transverse to said array and connections (8, 9) extending in longitudinal direction of said array and interconnecting said pins (7) and an array of carrier beams (10) each extending transverse to said array of pins (7) and connections (8, 9); at least one side barrier (11) extending above and along a side of said transport deck (5) for keeping bulk material from falling over a side edge of said transport deck (5), wherein said side barrier (11) is formed by an array of side barrier plates (24; 124), said side barrier plates (24; 124) each being fixedly connected relative to axes (35) of a pair of successive ones of said pins (7), and leading and trailing end portions (36; 137, 138, 140, 141) of successive ones of said side barrier plates (24; 124) being in at least close proximity of each other for keeping bulk material from passing in-between said end portions (36; 137, 138, 140,141), characterized in that successive ones of the side barrier plates (24) are connected relative to successive pairs of the pins (7), and end faces (36) of the side barrier plates (24; 124) facing each other are each curved about the axis (35) of the most adjacent one of the pins (7) fixedly connected relative to the respective one of said side barrier plates (24; 124). A conveyor according to claim 1, wherein the conveyor loop (2) further comprises a material carrying surface (27) having at least one side edge (28) facing said side barrier plates (24; 124). A conveyor according to claim 2, wherein said at least one side edge (28) of said material carrying surface (27) abuts said side barrier plates (24; 124). A conveyor according to claim 3, wherein said at least one side edge (28) presses against said side barrier plates (24; 124). A conveyor according to any one of the claims 2-4, wherein said material carrying surface (27) is formed by a flexible belt (30) carried by said carrier beams (10). A conveyor according to claim 5, further including mounting elements (32) having a foot (34) and at least one material entrainer (33) projecting from said foot (34), said belt (30) being clamped between feet (34) of said mounting elements (32) and said carrier beams (10). A conveyor according to any one of the preceding claims wherein said pins (7) are directly connected to said side barrier plates (24; 124). A conveyor according to claim 7, wherein said pins (7) have threaded ends threaded in threaded bores in said side barrier plates (24; 124). A conveyor according to claim 8, wherein ends of said pins (7) abut end faces of said carrier beams (10). A conveyor according to any one of the preceding claims, wherein said transport deck (5) has sections extending at different sloping angles. A conveyor according to any one of the preceding claims, further including a substantially stationary side guard (42) extending in longitudinal direction of said transport deck (5) and suspended above said transport deck (5) on a side of said side barrier plates (24; 124) facing away from said pins (7) and said connections (8, 9) of said array of pins (7) and connections (8, 9). A conveyor according to any one of the preceding claims, further comprising carrier rollers (19) supported by guide tracks (16, 17) and carrying said pins (7). A conveyor according to any one of the preceding claims further comprising guide rollers (43) mounted in substantially stationary positions and having circumferential surfaces (44) facing surfaces (45) of said side barrier plates (24; 124) facing away from said carrier beams (10). A conveyor according to any one of the preceding claims, wherein said side barrier plates (24; 124) are directly connected to ends of the transverse carrier beams (10).

Inventors: BOLLEGRAAF HEIMAN SALLE, BOLLEGRAAF, HEIMAN SALLE
Applicants: MACHF BOLLEGRAAF APPINGEDAM B, MACHINEFABRIEK BOLLEGRAAF APPINGEDAM B.V.
Application year: 2000
Main classification: B65G17
IPC codes: B65G17