BELT CONVEYOR SUPPORTING ARRANGEMENT

Abstract: In an apparatus for mitigating the drop impact of ores or the like using a buffer device (2) when they are transferred from a feeder or shooter S to a belt conveyor, a plurality of grooves extending in a belt conveying direction are formed on a slide support plate (3) of the belt (B) so as to reduce the contact area with the back of the belt and to reduce the heat of friction. An air stream fluidizing in the belt conveying direction is generated for cooling, and the gap between the shooter and a transfer apparatus is closed in such a manner that a skirt plate having a low friction resistance is supported so that it can be dropped under its own weight and the drop of the material to be conveyed outside the belt is prevented. Furthermore, on the return side of the belt, the belt is travelled while being curved at a predetermined angle of correction by inverted V-shaped rollers in order to prevent zigzag travel of the belt at the transfer surface and to prolong the life of the belt.

Description: This invention relates to a supporting arrangement for a belt conveyor which is used to convey bulk materials, such as ore, stone, coal etc. ; especially to one which is arranged at a position where bulk materials are transfered to a driven belt from a chute or feeder. When bulk materials such as ore, coal and stone are transfered from a chute or feeder to a belt conveyor, the belt tends to be damaged. Therefore, the chute or feeder are developed so as to lower the dropping energy onto the conveyor belt. For instance, a ladder or stone box L is mounted an the inside of the chute as shown Fig.11 so that the drop distance of bulk materials becomes shorter. Alternatively, the chute is usually designed with a throat portion and a pair of plate SC as the bulk materials tend to jump off the belt and lodge between carrier roller C and the belt B as shown in Fig. 12, in which R is a return roller. The portion of the belt positioned where bulk materials are transfered from the chute is supported by plural carrier rollers C, spaced from each other, so that the dropping materials jump about on the belt and engage between the belt and the rollers C, in this manner the belt tends to be damaged. Therefore, as shown in Fig. 13, it is proposed that the carrier roller is covered by rubber materials, the rollers are supported by rubber liners RL and also a carrier table T is supported by coil springs or an air cushion device SP. However, such remodeling is unwieldy and such roller supporting system fails to alleviate dropping impact between the carrier rollers. To avoid such problems, it has been proposed that a supporting arrangement for a belt conveyor comprised of a top plate P, made of high molecular polyethylene, which comes into contact with a running belt; an elastic plate R, made of natural or synthetic rubber, through which the top plate P is mounted on a supporting frame so as to support the conveyor belt B on a lubricous surface of the top plate and absorb the dropping impact by the elastic plate R (JP-U-60-137711 and JP-U-63-190106, both disclosing a supporting arrangement according to the preamble of claim 1). In such cases, however, there are some problems such that the top resin plate P becomes badly worn in a short time because it comes into constant surface contact with the running belt and thus the friction area is larger than that in a conventional roller supporting system, so that the resin plate tends to soften and wear out owing to friction heat. Futhermore, it is difficult to bend a resin plate having sufficient rigidity and thickness into the arc troughed shape, which is necessary to convey the bulk materials without excessive jumping on the belt surface. Therefore, as shown in Fig. 14, the resin plate is divided into at least 3 parts so that the belt enters into the opening D between the inclined support plates and the horizontal support plate and thus is worn away or cut down. In the worst cases, the supporting system itself comes to be damaged. Besides, the dropping impact can be lessened only to a limited extent with the elastic plate, so that the dropping materials still tend to jump or flow out through the opening between the chute S and the belt B, causing sanitation problems. It is proposed, therefore, that the opening must be closed by a rubber skirt plate, but it is inevitable that the plates and belt are cut down and wear unevenly because the bulk materials such as ores enter into the small opening between the skirt and belt (which widens with abrasion). Additionally, the bulk materials drop down from the chute onto the running belt at random, so that material cannot be loaded uniformly onto the receiving surface of the belt and thus the belt tends to run in zigzag. Such a zigzag running causes the belt to be worn locally. To avoid this problem, attempts have been made to adjust the tension of endless belt by tension pulleys, but it is difficult to avoid zigzag running. Accordingly, it is a primary object of the invention to provide an improved rollerless supporting arrangement for prolonging belt-life, and especially for improving the durability of a lubricous backing top plate as well as the belt. A secondary object of the invention is to provide a skirt shutting device, without damaging the belt, for avoiding outflow of dust or fine particles of bulk materials, in the proposed system. A further object of the present invention is to provide a return tension roller apparatus for avoiding zigzag running of the belt. To accomplish the above objectives, we have found that, providing a top lubricous plate with plural channels extending in the running direction of a belt at the plate surface, which is in contact with the belt, 1 ○ the contact area with the belt is diminished and thus the heat of friction can be decreasing between the belt and the top plate, and 2 ○ simultaneously an air flow in the running direction of the belt occurs in the plural channels owing to the belts running, and thus, cools the top plate in contact with the belt, so that the top plate can be maintained in good condition for a long time. Also, we have found that it is easy to bend the top stiff plate into the desire arc troughed shape owing to the plural channels on the surface thereof, without the need for any joint spaces, as shown in Fig. 14. In accordance with this invention, there is provided a supporting arrangement for a supporting arrangement for a conveyor belt which is positioned where bulk materials are transferred from a chute or feeder comprising a supporting frame extending in the running direction of the belt; a cushioning device mounted on the supporting frame for relieving dropping impact owing to bulk materials dropping onto the conveyor belt; a backing contact top plate with a lubricous surface for smoothly supporting the conveyor belt characterised in that the contact surface of the backing plate is provided with plural ribs extending in the running direction of the belt and defining therebetween a plurality of substantially parallel channels or grooves whereby the area of contact between the belt and the backing plate is significantly reduced and air flow along the channels is generated in the running direction of the belt. In a preferred configuration, the supporting frame has an arcuate sectional shape in a direction transverse to the running direction and can be attached on a conventional stand for rollers. The cushioning device can be formed to have a dropping impact lowering function and is preferably made of a rubber plate mounted in an arc shape along the arc surface on the supporting frame. In this case, the rubber plate tends to hang down to some extent between spaced frame members of the supporting frame owing to receiving repeat impact thereon. Therefore, it is prefered that the spaced frame members are covered at the upper side by a mesh plate in order to prevent the rubber plate from hanging down thereby maintaining the cushioning function thereof. As a backing plate, a slotted resin plate can be used. As shown in Fig. 10, long bar members 35 may be inserted and mounted into the slotted channels 31 to be detached in a longitudinal direction therefrom when desired but not to be detached upwardly therefrom by accident. Long bar members, have a rectangle section, which is made of lubricous heat-resistant material so that the upper surfaces of the bar members serve as a contact backing surface to the belt. In such a prefered case, the bar members can be replaced with new ones after abrasion, this is beneficial to lower the product cost of the backing plate if they are made of high cost resin materials. The contact backing plate may be preferably made of a synthetic resin plate having a superior heat resistance, such as teflon resin, ultra molecular polyethylene resin, heat resisting nylon resin. MC-nylon is best among them for the backing material. Generally plates of such materials having the desired thickness are difficult to bend into an arcuate shape having the desired curvature. However, since, according to this invention, the upper surface of the backing plate is provided with plural parallel channels in a longitudinal direction thereof, it is easy to bend the plate into an arc shape in the transverse direction and thus mount it on the rubber plate along the arcuate surface thereof. For achieving the secondary object in the above supporting arrangement comprising a supporting frame, a cushioning device on the frame, and a contact backing top plate on the device, there is provided a skirt plate device M2 for shutting the opening between the belt conveyor and the chute. This skirt plate device comprises a pair of plates made of lubricous resin material which extend in the running direction of the belt at respective sides of the belt and are supported upstream of the belt by a pivoted means so as to automatically descend by their own weight and contact the belt surface with little friction. In a prefered embodiment, as with the lubricous resin materials for production of the skirt plate, the use of high moleculer polyethylene resin, teflon resin or heat resisting nylon resin mentioned above, especially heat resisting nylon resin, for example MC-nylon, is recommended. In such a device, each skirt plate tends to lower by its own weight so that there occurs no gap between the plate and belt even as the lower part thereof wears. It is prefered, however, to adjust a weight of each skirt plate by arranging a balance-weight G, thereon, so as to prevent the skirt plate from jumping on the belt. For achieving the third objective in the above supporting arrangement comprising a supporting frame, a cushioning device mounted on the frame, and a contact backing top plate on the device, there is provided a bending tension roller apparatus comprised at least of a pair of rollers inclined in the opposite direction just like the symbol , the two rollers being linked to each other pivotably at one end axis thereof and at the other end axis thereof connected to the supporting table by means of a slidable connector, whereby the angle between the opposite inclined rollers can be adjusted to such a desired extent that the belt can be prevented from zigzag running. In such an apparatus, it is prefered that a pair of the inclined rollers is connected pivotably with a center connecting roller at both axes thereof. The above first arrangement M1, of this invention, includes a top contact plate provided with plural parallel channels at the surface therof, thereby the surface area contact with the running belt is decreased and the air flow occuring in the channels cools the surface of the contact plate. Additionally, the channels on the upper surface thereof permit the plate to be deformable into an arc troughed shape although it is made of a stiff material. Further, the above second arrangement M2, of this invention, provides automatically lowering lubricous skirt plates for shutting the opening above the belt, thereby bulk materials tend not to flow out from the belt surface and there occurs no cutting or local wearing problems caused by the entering of ores between the belt and the skirt plate. Furthermore, according to the above third arrangement M3, of this invention, a pair of the inclined rollers permits the belt at the return side to be forced into a desired arc troughed shape, so that there occurs no problem of abrasion caused by zigzag running of the belt owing to random loading. Accordingly with all these measures the belt for conveying bulk materials can be completely prevented from damage by the combination of the above three arrangements M1, M2 and M3, and the service life of the conveyor belt can be greatly extended. Many other features and advantages of the present invention will become apparent to those skilled in the art upon making reference to the detailed description which follows and the accompanying sheet of drawings. Fig.1 is a schematic elevational view showing a supporting arrangement for a belt conveyor suitable for carrying out a preferred embodiment of the present invention; Fig.2 is a sectional view taken on line II - II of Fig.1; Fig.3 is a perspective view showing only a rollerless supporting arrangement; Fig.4 is a perspective view showing only a top plate mounted on a cushioning plate; Fig.5 is a perspective view showing only a frame for supporting the combination plate shown in Fig. 4; Fig.6(a) is an enlarged fragmentary end vertical section showing a side end of Fig.2; Fig.6(b) is an enlarged fragmentary end vertical section showing a front end of Fig.3; Fig.7 is an enlarged fragmentary vertical section of the top plate; Fig.8 is an enlarged fragmentary elevational view showing a pivoted supporting portion of a skirt plate device M3; Fig.9 is a detailed sectional view on line IX - IX of Fig.1; Fig.10 is a fragmentary perspective view of an alternative embodiment of the top plate; Fig.11 is an elevational diagrammatic view of the prior art; Fig.12 is a front end view of the prior art; Fig.13 is a view of the prior supporting arrangement similar to Fig.2; and Fig.14 is a view of an alternative prior art supporting arrangement similar to Fig.2. In Fig.1, there is shown a belt conveyor arrangement comprised of an endless and arc troughed belt B which is supported in the running direction by means of a tension pulley TP and sustained by means of carrier table T mounted on a conveyor frame F. The belt can run in the arrow direction for conveying bulk material such as ore. On the carrier table T which is positioned where bulk material is transfered from a chute S, a belt supporting apparatus M1 is mounted. This is comprised of a supporting frame 1 made of steel constructed by plural arc lateral members 11, 11 spaced in a parallel relation connected with both side longitudinal members 12, 12 (Fig. 5) and a cushioning plate 2 mounted on the upper surface of the frame 1, which plate 2 may be made of natural or synthetic rubber and is of an appropriate thickness, for example about 30 mm, considering the impact load thereonto. Such a cushioning plate works as a resilient surface support for the belt receiving bulk material, thereby absorbing the dropping energy of bulk material at any position on the belt. On the above cushining plate, a contact top plate 3 made of lubricous material provided with plural channels 31 extending in the running direction of the belt and parallel-spaced in a lateral direction thereof, is mounted. As the lubricous material, it is prefered to use low friction materials such as heat resisiting nylon resin. The contact top plate is preferably designed to have 10∼20mm thickness and channels 31 spaced out at 20∼40mm intervals on the surface thereof which have 5∼10mm depth and 10∼20mm width. It is necessary to preform the contact top plate 3 into an arc troughed shape. The plural parallel channels make the plate itself easy to deform into the determined shape, as shown in Fig.3, whereby the deformed plate can rest upon the arc troughed surface of the cushioning plate 2. Attachment of the contact top plate on the supporting frame 1 can be carried out in the following manner. Firstly, both side edges 32 of the top plate 3 are cut out along the longitudinal arts thereof, on which cut portions are abutted and fixed detachably by means of flush belt 42. Pressing members are provided with a corresponding cut portion 41 as shown in Fig.7. In such a case, it is prefered to attach side longitudinal members 12, of the supporting frame 1 on a carrier table T by means of a rubber ring to protect the attaching portion from fatigue failure. In contrast, as shown in Fig.3, the contact top plate 3 is fixed at the front and back ends in that plural short fractions 34 separated by gaps extend downward from inclined parts 33 connecting to the belt contacting area, the short fractions being arranged like flower petals and engaging detachably over front and back arc members 11, 11. Such an arrangement permits the belt contact plate to have some lateral flexibility against belt lateral sliding and also sufficient cushioning function against bulk material dropping shock. Additionally, by means of plural parallel channels extending in the longitudinal direction, the belt contact area therewith decreases into half or two thirds of the total as well as cooling air flowing along the channels accompanied by the belt running thereon, so that the cooling effect is larger than in the case of total contact. As shown in Fig.8 and 9, between the chute S and the running belt B supported by the tranfer apparatus M1 there is inevitably formed an opening O extending in the running direction, which can be closed by means of the skirt plates 5 with little friction, if the weight that presses it in contact with the belt surface at the lower edge 5a is adjusted properly. The skirt plate 5 is arranged slidably between the lower portion of the chute S and adverse L shape members pivoted thereon and spaced from each other in a manner to lower downwardly by their own weight. Also, the skirt plate 5 is supported pivotably at the upstream side by an arm membr 8, expandable through an adjuster 83, where the arm member 8 is connected at one end 81 to a fan-shaped projection part 71 of a supporting member 7 in a manner that the connecting angle can be adjusted by means of bolt B1 as well as bolt B2 inserted in an arcuate hole 72, while at the other end 82, connected is a supporting pole 91 where both ends are pivotably supported by a pair of stands 9, 9 spaced out over the belt B positioned behind the tranfer apparatus M1. From the supporting pole 91, protruded in a diagonally upward direction, is a supporting member 92, on a selected position of which, through plural attaching holes 92a, is attached a balance height G to adjust the contact pressure against the belt surface. In such an arrangement, the skirt plate 5 automatically lowers and rests on the belt with a predetermined contact pressure at the lower end thereof, this pressure is adjusted by means of attaching the balance weight at a selected position. Further, the skirt plate 5 is cut out at the lower corner of upstream side thereof to abut smoothly against the belt. As shown in Fig. 9, at the return side opposite to the transfer position, there is arranged a tension return roller M3, for correcting the curve of the belt. In this roller apparatus, at both ends of an axis on which, rotatably mounted is a center tension roller R1, there are linked pivotably one end of an axis on which rotatably mounted is a pair of right and left rollers R2, R3 arranged to form a pivotably linked return roller system just like the symbol . As shown in Fig. 9, the site of joint portion J1 can be selected, while the rollers R2, R3 are jointed and slidably adjusted along the axis thereof by means of a screw adjuster at the remaining end thereof, so that the cross angles between the rollers R2, R3 and the center roller R1 can be changed by means of adjustment of the joints J1 and J2. Thereby, the portion of the belt at the return side can be corrected to be larger in the curve extent than at the receiving side thereof. In such an apparatus, the side rollers R2, R3 may be linked by a suitable means in place of the above center roller R1. As apparent from the above description, according to the above embodiments, the dropping energy of bulk material can be absorbed and thus alleviated by the arrangement for receiving bulk materials comprised of the cushioning device made of elastic material such as rubber which is curvedly arranged in a lateral direction on the supporting frame extending in the running direction of the belt. Further, the contact area between the belt and the top plate is reduced by about half or two thirds, and thus, the fraction resistance therebetween is reduced by half compared to that when the belt runs fully in contact with the top plate. This is achieved by means of the arrangement comprised of the top plate on which surface plural parallel channels extend in the running direction of the belt. Besides, along the plural parallel channels, cooling air comes to flow accompanied by the belt running in contact with the channels, thereby this air flow cools the contact surface thereof. For instance, it has been found that the surface temperature of the belt decreases 5°C below the ambient temperature in a unloaded condition, i.e. when no bulk material is loaded. It is apparent that the service life of the belt is greatly prolonged compared to a total contact supporting system. According to the arrangement comprised of the skirt plate device M2 for shutting the opening extending between the chute and the transfer apparatus by means of a low friction material plate which automatically lowers by its own weight, there is no excessive friction and there occurs little opening between the skirt plate and the belt. Therefore, the dropping bulk material is prevented from jumping out, even if it jumps on the receiving surface of the belt, so that all the bulk material can be completely conveyed to the determined place. Furthermore, according to the arrangement comprised of the tension return roller system M3 for correcting a deformable troughed belt, the belt running at return side is tensed by means of a pair of rollers R2, R3 opposite each other and inclined just like the symbol , as well as the belt being adjusted to a determined tension by a pair of tension pulleys, so that the belt can run without zigzag or lateral sliding even if local loading onto the receiving surface of the belt, thereby preventing the belt B from excessive contact with the transfer apparatus M1. These above functions and effects, such as the cushioning of the impact energy onto the belt, the diminishing of the contact frictional area with the belt, forced cooling of the belt, the closing of the opening between the belt and the chute as well as avoiding the zigzag running of the belt, etc. work together to prevent the belt from being damaged and wearing locally, and thus insure long belt service life.

Claims: A supporting arrangement for a conveyor belt which is positioned where bulk materials are transferred from a chute or feeder (S) comprising a supporting frame (1) extending in the running director of the belt; a cushioning device (2) mounted on the supporting frame (1) for relieving dropping impact owing to bulk materials dropping onto the conveyor belt; and a backing contact top plate (3) with a lubricous surface for smoothly supporting the conveyor belt characterised in that the contact surface of the backing plate is provided with plural ribs (35) extending in the running direction of the belt and defining therebetween a plurality of substantially parallel channels or grooves (31) whereby the area of contact between the belt (B) and the backing plate (3) is significantly reduced and airflow along the channels (31) is generated in the running direction of the belt. A supporting arrangement according to claim 1 wherein the supporting frame (1) has an arcuate sectional shape in a direction transverse to the running direction of the belt, the cushioning device is comprised of a rubber plate (2) and is mounted on the frame (1) so as to be in an arc troughed shape along the arcuate surface thereof, and the contact backing plate (3) is mounted on the rubber plate (2) so as to be in an arc troughed shape along the arcuate surface of the rubber plate 2. A supporting arrangement according to claim 2 wherein the supporting frame (1) is constructed from plural arcuate members (11, 11) spaced apart in parallel relationship and connected between respective longitudinal side members (12, 12) so as to be capable of being attached onto a conventional stand for rollers. A supporting arrangement according to claim 3 wherein a mesh plate overlies the spaced arcuate frame members (11) to prevent the rubber plate (2) from hanging down therebetween. A supporting arrangement according to any preceding claim wherein the contact backing plate (3) comprises a supporting body (30) provided with plural parallel slotted channels (31) extending in a longitudinal direction and bar members (35) of lubricous material detachably fitted in these channels such that the bar members (35) protrude above the surface of the supporting body (30) and define the channels or grooves therebetween. A supporting arrangement according to any preceding claim wherein at least the surface of the contact backing plate (3) is made of teflon resin or engineering nylon resin, such as MC-nylon. A supporting arrangement according to any preceding claim and further comprising a skirt plate device (M2) for shutting an opening between the belt conveyor and the chute, said skirt plate device comprising a part of skirt plates (5) made of lubricous material which extend in the running direction of the belt at respective sides of the belt and are supported upstream of the belt by pivoted means so as to lower automatically by their own weight and contact the belt surface with little friction. A supporting-arrangement according to any preceding claim and further comprising a bending tension roller apparatus (M3) which comprises at least a pair of rollers inclined in opposite direction to each other, the two rollers being linked to each other at one end of the respective axes thereof and connected at the other end of their respective axes to a supporting table by means of a slidable connector, whereby the angle between the oppositely inclined rollers can be adjusted to such an extent that the belt can be prevented from zigzag running.

Inventors: NAGAHAMA HIDEHARU, NAGAHAMA, HIDEHARU
Applicants: YOKO KK, KABUSHIKI KAISHA YOKO
Application year: 1989
Main classification: B65G21
IPC codes: B65G15, B65G21, B65G69