TURNING DEVICE FOR CONVEYOR BELT

Abstract: An endless conveyor belt (1) consists of a flexible material (2) and comprises two tensile-force-absorbing members (3, 4) which extend over the entire length of said conveyor belt and are each fixedly connected to a respective edge portion of the belt. A turning device for this conveyor belt comprises two deflection pulleys (5, 6) which are each positioned in one of two planes intersecting one another along an intersecting line (11). Means (12, 13; 18, 19) are arranged for guiding the tensile-force-absorbing members (3, 4) in first paths (14, 15) substantially from the intersecting line (11) and tangentially inwards to and in, respectively, second paths (20, 21) substantially towards the intersecting line and tangentially outwards from the circumference of the respective deflection pulley (5, 6). Means (18, 19; 22) are arranged for guiding the flexible material of the conveyor belt to a bag shape facing the first paths along the second paths from the deflection pulleys towards the intersecting line and, finally, moving together tensile-force-absorbing members essentially into contact with each other. Means (18, 19; 23) are arranged for turning the conveyor belt through at least 90 DEG around the longitudinal direction thereof directly after moving together the tensile-force-absorbing members.

Description: TURNING DEVICE FOR CONVEYOR BELT The present invention relates to a turning device for an endless conveyor belt consisting of a flexible material and having two tensile-force-absorbing members which extend over the entire length of the conveyor belt and are each fixedly connected to a respective edge por¬ tion of the belt. The turning device comprises two deflection pulleys which are each positioned in one of two planes intersecting one another along an intersecting line. Examples of conveyor belts which are suitable for the turning device are disclosed in US-A-4,915,213 and US-A-5,083,658, to which reference is now made. The former document describes, among other things, a con¬ veyor belt in which the tensile-force-absorbing mem- bers project from opposite sides of the belt in the straightened state thereof. The latter document describes a conveyor belt in which the tensile-force-absorbing mem¬ bers project from one and the same side of the conveyor belt in the straightened state thereof. These two con- veyor belts are such as to allow a closed conveyance of the goods involved. The goods can be emptied from the conveyor belt by passing this around deflection rollers or deflection pulleys. The essential thing is that, after passing the deflection roller or the deflection pulleys, the conveyor belt is prevented from letting out spillage of the material which after emptying may still be found on the goods-carrying side of the conveyor belt. The main object of the invention therefore is to provide a turning device of the type mentioned by way of introduction, which minimises the spillage from the end¬ less conveyor belt after its passing the deflection pul¬ leys and emptying the conveyed goods. According to the invention, this object is achieved by the turning device being characterised by means for guiding the tensile-force-absorbing members in first paths substantially from the intersecting line and tan¬ gentially inwards to and in, respectively, second paths substantially towards the intersecting line and tangen- tially outwards from the circumference of the respective deflection pulley, means for guiding the flexible mate¬ rial of the conveyor belt to a bag shape facing the first paths along the second paths from the deflection pulleys towards the intersecting line and, finally, moving together the tensile-force-absorbing members into contact with each other, and means for turning the conveyor belt through at least 90° around the longitudinal direction thereof directly after moving together the tensile-force- absorbing members, while the tensile-force-absorbing mem- bers are in contact with each other during the turning. Owing to this construction, it takes only a very short distance after passing the deflection pulleys to give the conveyor belt a closed shape. Normally, the means for guiding the tensile-force- absorbing members in the second paths substantially towards the intersecting line and tangentially outwards from the circumference of the respective deflection pul¬ ley, said means preferably having the shape of guide rollers cooperating with the tensile-force-absorbing members, are sufficient also as means for guiding the flexible material of the conveyor belt to a bag shape facing the first paths, or a reversed U-shape along the second paths from the deflection pulleys towards the intersecting line and, finally, moving together the tensile-force-absorbing members into contact with each other. However, in a preferred embodiment, a first support roller, which makes rolling contact with a goods- carrying side of the conveyor belt, can be arranged to secure the bag shape of the conveyor belt along the second paths of the tensile-force-absorbing members. It is also convenient that a second support roller is arranged to support the conveyor belt at a distance from the tensile-force-absorbing members during the turn¬ ing of the conveyor belt through at least 90° around the longitudinal direction thereof. Since the deflection pulleys are each arranged in one of two intersecting planes, the distance between the deflection pulleys will vary between a minimum distance and a maximum distance, the latter suitably essentially equalling the width of the conveyor belt. The optimum geometry of the turning device is obtained when the tensile-force-absorbing members are moved together essentially into contact with each other at the points where the first paths and the second paths, respectively, intersect the intersecting line which pre¬ ferably is symmetrically positioned relative to the deflection pulleys. For optimum utilisation of the turning device as an emptying device, the shafts of the deflection pulleys should be positioned in the same plane, make an obtuse angle with each other and make an angle smaller than about 45° with the horizontal plane. In this case, a satisfactory emptying will in fact be obtained even at a very low speed of the conveyor belt. In a preferred embodiment, the distance between the joining point of the first paths and the 'joining point of the second paths essentially equals the diameter of the deflection pulleys. In the embodiment described above, a frame, in which the deflection pulleys are mounted, can be positionable in an arbitrary position along a circular arc around the intersecting line. As a result, the discharging direction of the goods leaving the conveyor belt as this moves around the deflection pulleys can be changed within a relatively great range of angles, without affecting the remaining parts of a belt conveyor in which the turning device is included. To make a turning device of the type described above function in a satisfactory manner, it is extremely impor- tant that the deflection pulleys can be finely adjusted in the respective plane. To this end, each deflection pulley is suitably rotatably mounted on a shaft, which is adjustably mounted in the frame on an arm extending transversely of the shaft. According to the invention, the possibility of fine adjustment is achieved for each deflection pulley by means of an angle plate having two plate members directed transversely of one another. The shaft of the deflection pulley is mounted on one plate member so as to be, on the one hand, displaceable in its longitudinal direction and, on the other hand, tiltable about a first axis extending transversely of the longitudinal direction. The other plate member is mounted on the arm so as to be, on the one hand, displaceable in the longitudinal direction of the arm and, on the other hand, tiltable about a second axis which extends transversely of the shaft of the de¬ flection pulley as well as of the first axis. By means of the inventive angle plate, each deflec- tion pulley is adjustable relative to the frame with four degrees of freedom, which readily permits the desired fine adjustment of the position of the deflection pulley. An embodiment of an inventive turning device will now be described in more detail with reference to the accompanying drawings. The embodiment uses a conveyor belt according US-A-4,915,213, but can readily be changed to use a conveyor belt according to US-A-5,083, 658. Fig. 1 is a perspective view of a turning device according to the invention. Fig. 2 is a schematic top plan view of the turning device in Fig. 1. Fig. 3 is a schematic side view of the turning device in Fig. 1. Fig. 4 is a cross-sectional view of a conveyor belt in the positions indicated in Fig. 3. Fig. 5 is an end view of an adjusting device for a deflection pulley in the turning device according to Fig. 1. Fig. 6 is a view from below of the adjusting device in Fig. 5. Fig. 7 is a perspective view of a preferred embodi¬ ment of an angle plate included in the adjusting device according to Figs 5 and 6. Fig. 1 illustrates a turning device according to the invention at one end of a belt conveyor (otherwise not shown) having an endless conveyor belt 1. The conveyer belt 1 consists of a web 2 of a flexible and elastic material, and two tensile-force-absorbing members 3 and 4. The members 3 and 4 are each fixedly connected to a respective edge portion of the conveyor belt 1 and pro¬ ject from opposite sides of the conveyor belt, i.e. in opposite directions, when the conveyor belt 1 is in its transversely straightened state. The tensile-force- absorbing members 3, 4 extend over the entire length of the conveyor belt and preferably have the profile of a V-belt, although other profiles are also conceivable. The two tensile-force-absorbing members 3, 4 are further reinforced in the longitudinal direction so as to be but little extensible when absorbing tensile 'forces. The conveyor belt 1 travels in the direction of arrow A towards two deflection pulleys 5 and 6 which are included in the inventive turning device and are each rotatably mounted on a shaft 7 and 8, respectively. As shown in Fig. 2, the deflection pulleys 5, 6 are each positioned in a plane 9 and 10, respectively, which make an acute angle with one another and intersect one another along an intersecting line 11. The deflection pulley 5 has a planar circumferential surface, whereas the circum¬ ferential surface of the deflection pulley 6 comprises a groove for receiving the member 4. The conveyor belt 1 is conducted inwards with the tensile-force-absorbing members 3, 4 directed tangential- ly towards the circumference of the deflection pulley 5 and 6, respectively, which is achieved by means of guide rollers 12 and 13 which move together the tensile-force- absorbing members 3, 4 essentially into contact with each other at a point substantially on the intersecting line 11. Consequently, the tensile-force-absorbing members 3, 4 follow substantially straight paths 14, 15 from the intersecting line 11 into circumferential contact with the respective deflection pulley 5, 6. In the embodiment illustrated, the tensile-force-abscrbing members 3, 4 then follow the circumference of the deflection pulleys 5, 6 through an angle of about 180°. Owing to the configuration with the deflection pul¬ leys 5, 6 in the planes 9, 10, the central part of the conveyor belt 1 will, however, while turning around the deflection pulleys 5, 6, not follow a circular path, but form two or more, essentially stationary folds 16, 17 of the belt. As a result, goods conveyed on the conveyor belt 1 in the direction of arrow A will be thrown off from the conveyor belt 1 in the direction of arrow B with an excellent release effect relative to the goods-carry¬ ing surface of the conveyor belt 1. In consequence, only very small residues of the conveyed goods will remain on the goods-carrying surface of the conveyor belt 1 when this leaves the deflection pulleys 5, 6. As is evident from Fig. 1 and, in more detail, from Fig. 4 a-d, which illustrates the cross-sectional shape of the conveyor belt 1 in the positions a-d in Fig. 3, the conveyor belt 1 has a closed shape, the tensile- force-absorbing members 3, 4 essentially contacting each other up to the guide rollers 12, 13, whereupon the con¬ veyor belt 1 gradually opens to an almost planar shape in the outermost position on the deflection pulleys 5, 6, i.e. in the angular position of the deflection pulleys 5, 6, in which their mutual distance is at a maximum. From the lower side of the deflection pulleys 5, 6, the conveyor belt 1 is conducted towards two guide rollers 18, 19, which move together the tensile-force- absorbing members 3, 4 essentially into contact with each other at a point substantially on the intersecting line 11. The tensile-force-absorbing members 3, 4 move more precisely tangentially away from the circumferences of the deflection pulleys 5, 6 in substantially straight, second paths 20, 21 in between the guide rollers 18, 19. From the deflection pulleys 5, 6 to the guide rollers 18, 19, the web 2 of the conveyor belt 1 moves upwardly towards the first paths 14, 15, such that the web 2 forms a bag shape facing the first paths 14, 15 along the second paths 20, 21. The guide rollers 18, 19 are normal¬ ly sufficient to achieve this bag shape, but in order to absolutely secure the desired bag shape, a first support roller 22 can be arranged between the guide rollers 18, 19 and the deflection pulleys 5, 6, said first support roller 22 making rolling contact with the previously goods-carrying side of the conveyor belt 1, i.e. in this case, the lower side. By closing the conveyor belt 1 in reversed bag shape directly after leaving the deflection pulleys 5, 6, a very short distance is achieved, where residues of the conveyed goods, which remain on the conveyor belt, can be spilled by falling down from the conveyor belt 1. After passing the guide rollers 18, 19, where the conveyor belt 1 has a closed shape, it is turned around its longitudinal direction through at least 90° and pre¬ ferably 180°, as illustrated in Fig. 1. After such turn¬ ing, the conveyor belt can, in the remaining part of the return run, be conducted in its closed or open state, without risking further spillage, since the previously goods-carrying surface is now turned essentially upwards. To ensure clearance between the conveyor belt 1 and guide rollers (not shown) used for the turning, a second sup- port roller 23 can be arranged to support the conveyor belt 1 at a distance from the tensile-force-absorbing members 3, 4 in one or some positions during the turning of the conveyor belt 1 around its longitudinal direction, as schematically illustrated in Fig. 1. The shafts 7, 8 of the deflection pulleys 5, 6 are positioned in the same, preferably horizontal plane and make an obtuse angle with each other, as is evident from Fig. 2. More specifically, the shafts 7, 8 are each adjustably mounted on a transverse arm 24 and 25, respec¬ tively, of a frame 26. By the guide rollers 12, 13 as well as the guide rollers 18, 19 moving together the tensile-force-absorbing members 3, 4 essentially into contact with each other substantially at a point where the first paths 14, 15 intersect the intersecting line 11 and a point, respectively, where the second paths 20, 21 intersect the intersecting line 11, the inventive turning device can be made movable without affecting the rest of the belt conveyor. More precisely, this can be achieved by moving the frame 26 along a circular arc around the intersecting line 11, i.e. in the direction of arrow C or arrow D in Fig. 2. Correspondingly, the path of the con- veyor belt 1 inwardly towards the guide rollers 12, 13 and outwardly away from the guide rollers 18, 19 can run within a relatively wide angular field, without essentially affecting the inventive turning device, as indicated by arrows E, F in Fig. 2. The cross-sectional shape of the conveyor belt 1 on the exit side of the deflection pulleys 5, 6 is illu¬ strated in Fig. 4 e-h for the positions e-h indicated in Fig. 3. In the turning device according to the invention, the adjustment of the position of the deflection pulleys 5, 6 is very critical, and therefore a special adjusting device is provided for each deflection pulley 5, 6. This adjusting device for the deflecting pulley 5 is shown in Figs 5 and 6. More precisely, it comprises an angle plate 27 and four clamping means in the form of U-shaped yokes 28 with threaded ends. The angle plate 27 has two plate members 29, 30 which are directed transversely of one another and each have four through holes 31 for inserting the threaded ends of the yokes 28. The plate member 29 is attached to the shaft 7 by means of the yokes 28, whereby the shaft 7 abuts against a ridge 32 formed on the plate member 29 and directed transversely of the shaft. The shaft 7 and the angle plate 27 are thus tiltable relative to one another about the ridge 32 and can be set in the desired angular position by means of nuts on the free ends of the yokes 28. The arm 24 of the frame 26 is cor- respondingly fixable to the plate member 30, whereby this and the arm 24 are tiltable relative to one another about a ridge 34 formed on the plate member 30 and extending transversely of the longitudinal direction of the arm 24 and transversely of the longitudinal direction of the ridge 32. By means of the adjusting device as described above, each deflection pulley 5 can be set in the desired posi¬ tion with four degrees of freedom. For additional securing of the position of the shaft 7 relative to the plate member 29, the latter can be pro¬ vided with two lugs 35 and two lugs 36, whose respective mutual distance essentially corresponds to the width of the shaft 7. The plate member 30 can, on both sides of the ridge 34, be provided with two lugs 37 and two lugs 38, whose mutual distance essentially corresponds to the corresponding width of the arm 24. The man skilled in the art realises that the de¬ scribed embodiment of a turning device according to the invention can be modified in several respects with- in the scope of the appended claims.

Claims: CLAIMS 1. A turning device for an endless conveyor belt (1 ), which consists of a flexible material (2) and com¬ prises two tensile-force-absorbing members (3, 4) which extend over the entire length of the conveyor belt and are each fixedly connected to a respective edge portion of the belt, said turning device having two deflection pulleys (5, 6) which are each positioned in one of two planes (9, 10) intersecting one another along an inter¬ secting line (11), c h a r a c t e r i s e d by means (12, 13; 18, 19) for guiding the tensile-force-absorbing members (3, 4) in first paths (14, 15) substantially from the intersecting line (11) and tangentially inwards to and in, respectively, second paths (20, 21) substantially towards the intersecting line and tangentially outwards from the circumference of the respective deflection pul¬ ley (5, 6), means (18, 19; 22) for guiding the flexible material (2) of said conveyor belt ( 1) to a bag shape facing said first paths along said second paths from the deflection pulleys towards the intersecting line and, finally, moving together said tensile-force-absorbing members essentially into contact with each other, and means (18, 19; 23) for turning said conveyor belt through at least 90° around the longitudinal direction thereof directly after moving together said tensile-force-absorb¬ ing members. 2. The turning device as claimed in claim 1, c h a r a c t e r i s e d in that the shafts (7, 8) of said deflection pulleys (5, 6) are positioned in the same plane, make an obtuse angle with each other and make an angle smaller than about 45° with the horizontal plane. 3. The turning device as claimed in claim 1 or 2, c h a r a c t e r i s e d in that said tensile-force- absorbing members (3, 4) are moved together essentially into contact with each other substantially at the points where said first paths (14, 15) and said second (20, 21) paths, respectively, intersect said intersecting line (11). 4. The turning device as claimed in claim 3, c h a r a c t e r i s e d in that said deflection pulleys (5, 6) are mounted in a frame (26) which is placeable in an arbitrary position along a circular arc around the ' intersecting line (11). 5. The turning device as claimed in claim 3 or 4, c h a r a c t e r i s e d in that the distance between the joining point of said first paths (14, 15) and the join¬ ing point of said second paths (20, 21) essentially equals the diameter of said deflection pulleys (5, 6). 6. The turning device as claimed in claim 4, c h a r a c t e r i s e d in that each deflection pulley (5, 6) is rotatably mounted on a shaft (7, 8) which is adjustably mounted in said frame (26) on an arm (24, 25) extending transversely of said shaft. 7. The turning device as claimed in claim 6, c h a r a c t e r i s e d in that an angle plate (27) with two plate members (29, 30) directly transversely of one another is arranged for each deflection pulley (5), that the shaft (7) of said deflection pulley is mounted on one plate member (29) so as to be displaceable in its longi- tudinal direction and tiltable about a first axis trans¬ versely of the longitudinal direction, and said second plate member (30) is mounted on the arm (24) so as to be displaceable in the longitudinal direction of said arm and tiltable about a second axis which extends trans- versely of the shaft of said deflection pulley and of said first axis. 8. The turning device as claimed in claim 7, c h a r a c t e r i s e d in that the shaft (7) of said deflection pulley (5) and the arm, respectively, are attached to the respective plate member (29, 30) by means of two clamping devices (28), between which said plate member comprises a ridge (32, 34) directed transversely of said shaft and said arm, respectively, such that said shaft and said arm, respectively, are tiltable on said ridge and fixable in the desired angular position by means of the clamping devices. 9. The turning device as claimed in any one of claims 1-8, c h a r a c t e r i s e d in that one deflec¬ tion pulley (5) /has a smooth circumferential surface, and the other deflection pulley ( 6) has a grooved circumfe¬ rential surface for cooperation with a conveyor belt (1 ) , whose two tensile-force-absorbing members (3, 4) project from different sides of said conveyor belt. 10. The turning device as claimed in any one of claims 1-9, c h a r a c t e r i s e d by a first support roller (22) which makes rolling contact with a goods-car- rying side of said conveyor belt (1) for ensuring the bag shape of said conveyor belt along the second paths (20, 21) of said tensile-force-absorbing members (3, 4). 11. The turning device as claimed in any one of claims 1-10, c h a r a c t e r i s e d by a second sup- port roller (23) for supporting said conveyor belt (1) at a distance from said tensile-force-absorbing members (3, 4) during the turning of said conveyor belt through at least 90° around the longitudinal direction thereof. 12. The turning device as claimed in any one of claims 1-11, c h a r a c t e r i s e d in that the greatest distance between the circumferences of said deflection pulleys (5, 6) essentially equals the width of said conveyor belt (1 ) .

Inventors: JOHANSSON ROBERT, JOHANSSON, ROBERT
Applicants: SICON ROULUNDS AKTIEBOLAG
Application year: 1995
Main classification: B65G15
IPC codes: B65G15