WO1988006135A1

WO1988006135A1 - Belt conveyor

Info

Publication number: WO1988006135A1
Application number: PCT/SE1988/000072
Authority: WO
Inventors: Lennart Tingskog
Original assignee: Lennart Tingskog
Priority date: 1987-02-20
Filing date: 1988-02-19
Publication date: 1988-08-25
Also published as: SE462088B; AU1369988A; SE8700709D0; SE8700709L

Abstract

A belt conveyor comprises an endless conveyor belt (5) which is substantially U-shaped in cross-section. The conveyor belt has a base portion (6) with a central, longitudinal bead (7) on the lower side and two substantially flat lateral portions (9, 10) joined to the base portion and rigid relative to the longitudinal axis of the conveyor belt. Furthermore, the belt conveyor has a plurality of rollers distributed along its goods conveying path and comprising on one hand supporting rollers (11) on which the bead (7) rests, and on the other hand lateral guide rollers (14, 15) which bear against the upper part of the outside of each lateral portion (9, 10) to retain this in a substantially vertical position such that the weight of the conveyor belt and of the goods (16) conveyed in the belt is absorbed by the supporting rollers via the base portion and the bead.

Description

BELT CONVEYOR

The present invention relates to a belt conveyor of high conveying capacity under severe operating con¬ ditions for conveying such goods as coal and ore.

Prior art conveyors for such conveyance are unpro- fitable because of the high manufacturing, mounting or maintenance costs involved. Further drawbacks arise because these conveyors are usually bulky and difficult to contain, or cause material to be spilled from the return part. Finally, their construction often prevents conveyance through tight curves and at sharp angles.

It therefore is the object of the present invention to provide a belt conveyor that eliminates or at least reduces most of the above-mentioned disadvantages of prior art conveyors. According to the invention, this object is achieved by a belt conveyor comprising an endless conveyor belt which is substantially U-shaped in cross-section along the goods conveying path of the belt conveyor, and has a base portion and two lateraj. portions joined to said base portion, and also comprising a plurality of rollers distributed along the conveyor belt to support the same, and guide means to maintain the U-shape of the conveyor belt at least along the goods conveying path by cooperating with the outside of said lateral portions, substantially as a result of the belt conveyor being characterised in that the base portion has a longitudinal bead in a central region of its lower side along the goods conveying path; that said lateral portions are flat and rigid relative to the longitudinal axis of the conveyor belt; and that the conveyor belt is supported along the goods conveying path by supporting rollers on which said bead rests, and is guided laterally by means of guide rollers cooperating with the lateral surfaces of said 2 bead, such that the whole weight of the conveyor belt and of the goods conveyed therein is absorbed by the supporting rollers via the bead of the base portion.

The lateral guide rollers preferably bear against the upper portion of the outside of the associated lateral portion. Furthermore, the height of the lateral portions is substantially greater than the width of the base portion, preferably at least two and normally three times greater. In the preferred embodiments of the invention, the lateral portions are hingedly con¬ nected to the base portion.

The base portion and the lateral portions of the conveyor belt can be manufactured in one piece of a rubber material and with several inserts to make the lateral portions rigid and hingeable relative to the base portion.

By using^' a terminal roller over which the conveyor belt travels in a laterally straightened condition, the conveyor belt can follow a return path in a position either above or below the position of the conveyor belt along the goods conveying path. The lateral por¬ tions of the conveyor belt are in this case turned downwardly from the base portion and rest with their free edges on supporting rollers, the free edges being preferably reinforced to be able to support the conveyor belt.

Alternatively, the conveyor belt lateral portions may be directed upwardly from the base portion along the whole length or substantially the whole length of the belt. In this case, it is not necessary that the lateral portions are hingedly connected to the base portion. Along a return path, the conveyor belt may then also be travelling in a position beside the position of the conveyor belt along the goods convey- ing path.

It will be appreciated that the belt conveyor ac¬ cording to the invention, because of the relatively small width of the belt compared to its height, can travel through relatively tight curves. This means that the belt conveyor according to the invention can carry out conveying work that would require one or several reloading operations with prior art belt conveyors. Furthermore, the belt conveyor according to the invention is easy to contain and is also compact and has an adaptable cross-section. More precisely, the height of the belt conveyor can be made relatively small by disposing the belt parts of the goods conveying path and the return path side by side, or the width of the belt conveyor can be made extremely small by disposing the belt parts of the goods conveying path and the return path on top of one another. in the case where the conveyor belt parts of the goods conveying path and the return path are disposed side by side, the belt conveyor according to the inven¬ tion permits two-way conveyance. If the path of the conveyor belt is such that the lateral portions are directed upwardly from the base portion along the whole path, the belt conveyor according to the inven¬ tion is particularly useful for circulation conveyance between a plurality of stations arbitrarily disposed along the belt conveyor and adapted for loading goods on the conveyor belt or discharging goods from the conveyor belt. Such a circulation conveyance may occur in, for example, silo installations.

Combining, in accordance with the present inven¬ tion, a relatively narrow base portion with vertical, rigid, lateral portions, gives the advantage of a high loading capacity in combination with the possi¬ bility of conveyance through relatively tight curves. The construction furthermore is such that the manu¬ facturing and mounting costs become relatively low, and that also the maintenance costs remain at a low level thanks to the anticipated high longevity of the belt and the easy access to the rollers. Provid- ing the base portion with a bead gives the further advantage that relatively few supporting rollers are required, on the one hand because but one row of sup¬ porting rollers is needed and, on the other hand, because the bead and the base portion can be made relatively rigid, and hence the supporting rollers can be spaced relatively far apart.

The invention will be described in more detail below, reference being had to the accompanying drawings. Fig. 1 is a cross-sectional view of a first embodiment of a belt conveyor according to the invention. Fig. 2 illustrates a preferred alternative to the embodiment of Fig. 1. Fig. 3 is a cross-sectional view of a se¬ cond embodiment of the belt conveyor according to the invention. Fig. 4 is a cross-sectional view of a curve portion of a belt conveyor according to the invention. Fig. 5 shows an alternative embodiment of a supporting roller as well as alternative embodiments of derailment protection devices. Fig. 6 illustrates two possible shapes of the cross-section of the belt along a return path. Fig. 7 shows a preferred embo¬ diment of the cross-section of the conveyor belt. Figs 8-11 illustrate alternative possibilities of discharging goods from a belt conveyor according to the invention. Fig. 12 illustrates an alternative cross-sectional shape of a belt bead according to the invention. Fig. 13 illustrates, partly in longitu¬ dinal section, a terminal roller usable in the belt conveyor according to the invention. In the embodiment shown in Fig. 1 of a belt con¬ veyor according to the present invention, a plurality of roller stands are mounted in a supporting frame comprising posts 1, 2 and crossbars 3, 4. Through the lower part of the supporting frame, a conveyor belt 5 travels along a goods conveying path, and through the upper part of the supporting frame the same con¬ veyor belt 5 travels along a return path. The conveyor belt 5 thus is endless and is substantially U-shaped in cross-section. It comprises, more precisely, a base portion 6 having a longitudinal bead 7 on its lower side. Two substantially vertical lateral por- tions 9 and 10 are joined to the base portion 6. The bead 7 rests on a supporting roller 11 rotatably mounte on a horizontal axis. It is substantially rectangular in cross-section, and pairs of opposing guide or drive rollers 12, 13 bear against the lateral surfaces of the bead and are mounted rotatably about vertical axes. The rollers 11-13 are supported in roller stands mounted on the crossbar 4. On the posts 1 and 2, there are rigidly mounted two roller stands in which lateral guide rollers 14 and 15 are mounted rotatably about vertical axes. These lateral guide rollers 14, 15 bear against the upper portion of the outside of each lateral portion 9, 10 to retain the lateral portion in a substantially vertical position against the action of the outwardly directed pressure the transported goods 16 exert on the lateral portions 9, 10.

To prevent the lateral portions 9, 10 from leaving their substantially vertical position when the conveyor is running without goods, guide means 17, 18 are mounted on brackets 19, 20 attached to the posts 1, 2. The guide means 17, 18 extend downwardly to a position below the upper free edge of the lateral portions 9, 10 on the inside of the lateral portions.

As a supplementary protection against derailment, shoulders 21, 22 are mounted on the inside of the posts 1, 2 at the lower portion of the outside of each lateral portion 9, 10. Between the outer edge of the shoulders 21, 22 and the lateral portions 9, 10 there is a clearance or play.

The brackets 19, 20 also serve as a roller stand for a supporting roller 23 mounted rotatably about a horizontal axis and supporting the return part of the conveyor belt 5. In this embodiment, the lateral portions 9, 10 are directed downwardly from the base portion 7 along the return path and are urged against one another by two pairs of pressure rollers 24, 25 and 26, 27 respectively, which are mounted rotatably about vertical axes and supported in roller stands attached to the posts 1 and 2. In the crossbar 3, there is mounted a roller stand with a roller 28 mounted rotatably about a horizontal axis and forming a protec¬ tion against vertical derailment of the return part of the conveyor belt 5. Normally, however, the roller 28 is out of contact with the bead 7.

As is seen from the above, the whole or essential¬ ly the whole weight of the conveyor belt 5 and of the goods 16 conveyed therein is carried by the sup- porting roller 11 via the base portion 6 and the bead 7. The lateral guide rollers 14 and 15, therefore, do not normally take up any weight, but serve merely to retain the lateral portions 9, 10 in an essentially vertical position. Instead of, as in Fig. 1, permitting the return part to take a position above the goods conveying part, the return part can be placed below the goods conveying part, as is illustrated in Fig. 2. The embo¬ diment of Fig. 2 is advantageous in that goods can be loaded in the conveyor belt at any place along at least the straight runs of the conveyor, as a result of the upper crossbar 3 being omitted. Furthermore, the roller 28 shown in Fig. 1 is not needed since its function has been taken over by the supporting roller 11. Finally, the guide rollers 26, 27 engage directly with the sides of the bead 7.

In another embodiment of the invention, the return part of the conveyor belt 5 is placed in a position beside the goods conveying part. The goods conveying part of the conveyor belt 5 is supported and guided by rollers in the same way as in the embodiment of Fig. 1, although a cover bar 29 is mounted over the conveyor belt in order to essentially seal the opening between the upper free edges of the lateral portions 9, 10. In this manner, a contained goods conveyance is achieved. In the embodiment of Fig. 3, also the return part of the conveyor belt 5 is supported via the bead 7, and a pair of pressure rollers 30, 31 bear against the outside of the upper parts of the lateral portions 9, 10 to keep these together. The rollers 30, 31 are mounted rotatably about vertical axes. To prevent the return part of the conveyor belt 5 from derailing, a roller 32 is mounted rotatably about a horizontal axis immediately above the upper free edges of the lateral portions 9, 10.

Fig. 4 illustrates a preferred embodiment of the guide rollers along a part of the conveying path where the conveyor belt 5 travels through a curve substantially in the plane of the base portion 6, in this case the horizontal plane. Along the whole curve, a plurality of guide rollers are disposed, and two such guide rollers 33, 34, are shown in Fig. 4. More precisely, the guide rollers 33, 34 are mounted rotatably about vertical axes and bear against the uppermost part of the inside of each lateral portion 9, 10. A lateral guide roller 35 which is journalled in bearings for rotation around a vertical axis, bears against substantially the whole part of the outside of the lateral portion 10 located externally in the curve, and therefore replaces both the lateral guide roller 15 and the derailment protection means 22 which are disposed along straight runs of the goods conveying part. By means of the rollers 33-35, the conveyor belt is effectively guided through curves.

Fig. 5 illustrates an alternative embodiment of the conveyor belt 5. In this embodiment, the bead 7 is also of rectangular shape, but could be shaped as a V-rope, and the rollers 11-13 are replaced by a belt disk 36 with the profile of a V-rope. As is indicated in Fig. 5, rollers 37, 38 can be used as derailment protection means. These rollers 37, 38 can be journalled to bear resiliently against the lateral portions 9, 10, but with a limited possibility of compressing the conveyor belt.

Fig. 6 illustrates two further ways to dispose pairs of pressure rollers for compression of the lateral portions 9, 10 of the return part of the conveyor belt 5. As a result of the compression, the return part can be urged to travel in a manner so as to de¬ scribe curves having a smaller radius of curvature than the goods conveying part of the conveyor belt 5. The preferred embodiment of the belt 5 is shown in Fig. 7. The base portion 6 and the lateral portions 9, 10 are in this case made of a rubber material and in one piece together with a plurality of inserts 39-41. The insert 39 is disposed at approximately the same distance from the upper and lower surfaces of the base portion 6 and is of such construction that it permits flexing of at least the outer parts of the base portion 6 relative to the longitudinal axis of the conveyor belt 5. However, other embodi¬ ments of the insert 39 are possible. The inserts 40, 41 in the lateral portions 9, 10 are, on the other hand, located in the surface layer of the lateral portions 9, 10 and are constructed such that the lateral portions 9, 10 are rigid relative to the longitudinal axis of the conveyor belt. As a result of this rigidity, the lower parts of the lateral portions 9, 10 are pre- vented from bulging, even if the conveyor belt 5 is filled with goods and the only retaining force exerted on the lateral portions 9, 10 is derived from the lateral guide rollers 14, 15.

The lateral portions 9, 10 are preferably also rigid relative to a vertical axis, although this rigi¬ dity must not be so high that it prevents the conveyor belt 5 from travelling through relatively tight curves. The bead 7 is preferably of rectangular shape and includes a means 42, such as a wire, for absorbing tensile forces. The bead 7 can be vulcanised to the lower side of the base portion 6. In order to improve the support of the conveyor belt 5 along a return path where the lateral portions 9, 10 are directed downwards relative to the base portion 6, the free edges of the lateral portions 9, 10 are provided with reinforcing flanges 43, 44. Figs 8-11 illustrate different ways to discharge goods from a belt conveyor according to the invention. The goods conveyor shown in Fig. 8 is of the same kind as the one schematically shown in Fig. 2. More precisely, the conveyor belt 5 is passed over a termi- nal roller 45 in a laterally straightened condition, whereby the conveyed goods will leave the conveyor belt 5 at the moment when the travelling direction of the belt around the terminal roller 45 changes. Along a certain distance ahead of the terminal roller 45, special guide rollers are disposed which permit the cross-sectional shape of the belt 5 to change from U-shape to a completely straight shape. When leaving the terminal roller 45, the conveyor belt 5 is preferably made to resume its U-shape, but now the lateral portions 9, 10 are directed downwardly from the base portion 6. Along the return path, the conveyor belt 5 can, however, also travel in the same condition as when passing over the terminal roller 45. The belt conveyor shown in Fig. 9 is of the type shown in Fig. 1. Discharging is here carried out via a terminal or deflecting roller 46, down onto e.g. a second belt conveyor 47 travelling in a direction transverse to the plane of the drawing. By means of two further deflecting rollers 48 och 49 the conveyor belt 5 is urged to return along a return path located above the goods conveying path. Conveyed goods can also be discharged from the belt conveyor according to the invention by pivoting one of the lateral portions downwardly relative to the base portion 6 over a limited distance. This is illustrated in Fig. 10 which also shows how a plurality of rollers 50-52 are used to retain one lateral portion 9 in an essentially vertical position and to guide the pivoting of the other lateral portion 10 downward¬ ly to a position in which it slopes downwardly and in which the conveyed goods 16 are discharged from the conveyor by gravity or, optionally, by means of a scraper.

Fig. 11 illustrates another way to discharge goods from the conveyor belt 5 down onto e.g. a con- veyor 56 travelling in a direction transverse to the plane of the drawing, by means of three deflecting rollers 53-55.

As is seen from the cross-sectional view in Fig. 12, the bead 7 can alternatively have protruding lateral por- tions 57, 58 for cooperation with the guide rollers 12, 13 which in this case have a peripheral surface, the profile of which corresponds to the profile of the pro¬ truding portions 57, 58. In this manner, the guide rollers 12, 13 will bear against the lateral surfaces of the bead 7 and engage with these in such a way that the bead is vertically immobile.

The terminal and deflecting rollers 45, 46, 53 and 55 illustrated in Figs 8, 9 and 11 can be shaped as shown in Fig. 13, i.e. they have a central groove 57 to accommodate the bead 7 and grooves 58 and 59 on each side of the groove 57 to accommodate the outer parts of the base portion 6.

A great many modifications of the embodiments described above are possible within the scope of the invention. For example, plastic layers of high strength can be used as means for absorbing tensile forces, instead of the wire 42. The lateral guide rollers 11 14, 15 cooperating with the outside of the lateral portions 9, 10 can be replaced by other lateral guide means, such as slide ledges, which can be operated by compressed air. Furthermore, the lower support bearing for the roller 35 can be made resilient. Fi¬ nally, it should be mentioned that the belt can be run at a relatively sharp angle, the belt starting and ending its passage of the inclined path through a 90° curve.

Claims

1. Belt conveyor comprising an endless conveyor belt (5) which is substantially U-shaped in cross- section along the goods conveying path of the belt conveyor, and has a base portion (6) and two lateral portions (9, 10) joined to said base portion, and also comprising a plurality of rollers (11) distributed along the conveyor belt to support the same, and guide means (14, 15) to maintain the U-shape of the conveyor belt at least along the goods conveying path by coope- rating with the outside of said lateral portions, c h a r a c t e r i s e d in that the base portion (6) has a longitudinal bead (7) in a central region of its lower side along the goods conveying path; that said lateral portions (9, 10) are flat and rigid rela- tive to the longitudinal axis of the conveyor belt (5); and that the conveyor belt is supported along the goods conveying path by supporting rollers on which said bead rests, and is guided laterally by means of guide rollers (12, 13; 36) cooperating with the lateral surfaces of said bead, such that the whole weight of the conveyor belt and of the goods (16) conveyed therein is absorbed by the supporting rollers via the bead of the base portion.

2. Belt conveyor according to claim 1, c h a - r a c t e r i s e d in that the lateral portions (9,

10) are hingedly connected to the base portion (6).

3. Belt conveyor according to claim 2, c h a ¬ r a c t e r i s e d in that the base portion and the lateral portions (6; 9, 10) of the belt conveyor (5) are manufactured in one piece of a rubber material and with several inserts (39-41) to make the lateral portions rigid and hingeable relative to the base portion.

13 4. Belt conveyor according to claim 2 or 3, c a r a c t e r i s e d by at least one terminal roller (45 over which the conveyor belt (5) travels in a laterally straightened condition.

5. Belt conveyor according to any one of claims 2-4 c h a r a c t e r i s e d in that the conveyor belt (5) is urged to follow a return path in a position either above (Fig. 1) or below (Fig. 2) the position of the conveyor belt. along the goods conveying path, the lateral portions (9, 10) in this case being turned down¬ wardly from the base portion (6) and resting with their free edges on supporting rollers (23).

6. Belt conveyor according to claim 5, c h a ¬ r a c t e r i s e d in that the free edges of the lateral portions (9, 10) are reinforced (43, 44).

7. Belt conveyor according to any one of claims 1-4 c h a r a c t e r i s e d in that the conveyor belt

(5) travels along a return path in a position beside the position of the conveyor belt along the goods con- veying path (Fig. 3).

8. Belt conveyor according to any one of claims 1-7 c h a r a c t e r i s e d in that the bead (7) comprise a means (42) for absorbing tensile forces.

9. Belt conveyor according to any one of claims 1-8 c h a r a c t e r i s e d in that the height of the la¬ teral portions (9, 10) is substantially greater, prefer¬ ably at least two times greater, than the width of the base portion (6) .

10. Belt conveyor according to any one of claims 1- c h a r a c t e r i s e d in that the bead (7) is sub¬ stantially rectangular in cross-section.

11. Belt conveyor according to any one of claims 1-9 c h a r a c t e r i s e d in that the lateral surfaces of the bead (7) have protruding portions (57, 58) dis- posed to engage the lateral guide rollers (12, 13).

12. Belt conveyor according to any one of claims 1-1 c h a r a c t e r i s e d in that it travels through a curve substantially in the plane of the base portion (6); and that a plurality of further rollers (33, 34) are distributed along the curve and bear against the uppermost part of the inside of each lateral portion (9, 10).

13. Belt conveyor according to any one of claims 1-1 c h a r a c t e r i s e d by derailment protection means (21, 22; 37, 38) disposed along at least the goods con¬ veying path and located at the lower part of the outside of each lateral portion (9, 10), preferably in spaced apart relation to said lateral portion.

14. Belt conveyor according to any one of claims 1-1 c h a r a c t e r i s e d in that the lateral guide rol¬ lers (14, 15) along the goods conveying path bear against the upper part of the outside of the lateral portions (9, 10).

15. Belt conveyor according to any one of claims 1-1 c h a r a c t e r i s e d in that the supporting rollers (36) also serve as lateral guide rollers for the bead (7)