A BELT CONVEYOR

Abstract: A belt conveyor (21), in particular suitable for vulnerable products, such as agricultural and horticultural products, comprising a conveyor belt (21) guided along two return rollers (41, 42) and a plurality of support members (22) and side walls (23, 24) laterally bounding the transport path defined by the conveyor belt (21). The side walls (23, 24) are each formed by a side strip of the conveyor belt (21), which side strip extends obliquely downwards towards the portion of the belt supported by the support members. The side strip (23, 24) is supported by a platelike portion (27) of a side frame section bent from plate material (28).

Description: This invention relates to a belt conveyor, in particular suitable for vulnerable products, such as agricultural and horticultural products, comprising a conveyor belt guided by two return rollers and a plurality of support members; at least two hollow opposite side frame sections bent from sheet material and open at the underside and each having a platelike portion which in cross-sectional view extends obliquely downwards and in the direction of the other side frame section and supports in use a side strip portion of the conveyor belt, said obliquely downwards extending platelike portion at its lower end having a depending inner flange facing a similar inner flange of the opposite side frame section, wherein the support members are mounted between said inner flanges. Belt conveyors of this kind can be used for agricultural products, such as fruits, bulbs, tubers, potatoes and the like, and can be constructed as a horizontal conveyor or as an elevator, whether or not mounted on a mobile carriage. Furthermore, such conveyors may be telescopic. For increasing the transport capacity, upwardly sloping side plate sections formed from sheet material and supporting a side strip portion of the conveyor belt may be positioned along the conveyor belt of the known conveyors. Such a conveyor, designed for use as a substantially horizontal conveyor for mining products has been disclosed in FR-A-1028163. A drawback of the known conveyor is that it is comparatively heavy, so that, in particular when telescopic mobile low-bin fillers are concerned, a heavy carriage is necessary. Also the side plate sections are rather flat and do not provide an optimum transport capacity. Moreover, it is difficult with the known conveyor to make a telescopic embodiment wherein the height of the side strips of the conveyor belt at the transition between the main transport portion and the telescopic portion, and on the telescopic portion itself can be maintained. If the side guide is omitted along a part of the transport path, or is less high, the total transport capacity, however, decreases also, which is undesirable. It is an object of the present invention to remove the above drawbacks and to provide in general an effective, improved conveyor suitable in particular for transporting vulnerable products in large quantities. To that end, according to a first aspect of the invention, a belt conveyor of the above described type is characterized in that said side frame sections each are completely open as viewed in longitudinal direction, and in that said platelike portions of the side frame sections are steeply inclined and support the side strip portions of the conveyor belt in such a manner that said side strip portions form side wall portions moving together with the bottom portion of the conveyor belt, which side wall portions reach up to near the upper ridges of the side frame sections. Some embodiments of the present invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a cross-sectional view of an example of a belt conveyor known from actual practice, having a transport capacity increased by upright side wall plates; Fig. 2 is a cross-sectional view of an embodiment of a conveyor according to the invention; Fig. 3 is a cross-sectional view of an example of a telescopic conveyor according to the invention; Fig. 4 is a side view of an example of a conveyor according to the invention; and Fig. 5 shows a variant of Fig. 4. Fig. 1 shows a belt conveyor known from actual practice, comprising a belt 1, provided in this example on the transporting surface with carriers, such as chevrons or cross ribs 2, and which is guided along support rollers 3,4, downwardly inclined towards the centre of the belt, for increasing the transport capacity. Extending obliquely upwardly from the side edges of the conveyor belt are walls 5,6, formed from plate material, said walls being mounted on side frame portions 7,8 of the conveyor. The side frame portions form part of a frame mostly constructed as a lattice construction with longitudinal girders 9,10 and cross bars 11 mounted at uniform interspaces between side frame portions, said cross bars carrying supports 12 for the shafts 13 of the rollers 3,4. As a result of the trough shape obtained by the concave conveyor belt and the upright side walls, the material to be transported can be conveyed by the conveyor belt in a thick layer. A drawback is that a part of the material to be transported during transport slides along the walls 5,6, which may cause damage to vulnerable products, such as agricultural products. Another drawback is that problems arise in the known apparatus during the transport e.g. of cereals, pulse crop and the like, due to the chinks present between the side edges of the conveyor belt and the fixed side walls. Still another drawback is that in a telescopic construction of the prior art conveyor the telescopic portion including the side walls, should be provided underneath the cross bars 11. As a consequence, there is a substantial difference in height at the transition to the telescopic portion, which is bridged by the conveyor belt adapting itself gradually to the lower level of the telescopic portion. As a result,however, the side walls in this transitional region come to lie entirely or partially below the level of the conveyor belt, which may considerably limit the total transport capacity of the conveyor. Sometimes, therefore, no side walls are used on the telescopic portion or lower ones, which also limits the transport capacity. Fig. 2 is a cross-sectional view of an example of a belt conveyor according to the present invention. The belt conveyor shown in Fig. 2 has a belt 21 provided in this example with a moulding 20, said belt being guided over straight support rollers 22. Furthermore, there are provided stationary side walls 23,24 made from plate material and extending obliquely upwardly on either side of the transport path. Contrary to what is the case in the apparatus shown in Fig. 1, the side edges of the conveyor belt in the apparatus according to the invention shown in Fig. 2 are inclined upwardly against the comparatively steep side walls 23,24, so that the conveyor belt itself forms a cross-sectionally trough-shaped transport path. The conveyor belt, consequently, is supported with its central region on the support rollers 22 and with the edge regions on the side walls. As the side walls are made from plate material and are smooth, the friction occurring between the conveyor belt and the side walls is not objectionable. It is observed in this connection that stationary support faces, instead of support rollers, are sometimes used. The result of the configuration described, actually is a conveyor track with side walls moving along with it, thereby excluding damage to products to be transported due to friction against the side walls. Moreover, a conveyor of this kind is highly suitable for transporting small or granular material and the like, since there is no longer a chink between the belt and the side walls and since, insofar as the side walls extend to above the inclined side strips of the conveyor belt, there is an intimate, properly sealing contact between the belt and the side walls. In practice, the side walls do not extend beyond the inclined strips of the conveyor belt, or hardly so. In an embodiment reduced to practice of a conveyor according to the invention, the flat bottom of the trough-shaped conveyor belt may occupy 50% or more of the width of the conveyor belt, while the side walls may enclose an angle of 55° or more with the horizontal plane. There is thus obtained a substantial transport capacity, as well as a strong construction. It is observed already now that in a telescopic conveyor according to the present invention, the trough shape of the conveyor belt is substantially maintained at the transition to the telescopic portion. This is additionally promoted by features to be described hereinafter. According to the invention, side walls 23,24 each form part of a section made from plate material and which, according to the principle of the chassisless body known from the motorcar art, at the same time forms the side frame of the conveyor. Each section has an upper triangular portion 26, with the apex of the triangle being directed upwards and the base lacking. One side of the triangular portion is formed by either of the above described side walls 23,24 and the other side 27 extends from the apex obliquely outwards and downwards. Approximately at the level of the under-side of the conveyor belt, side 27 passes into a substantially vertical portion 28 which, as shown in Fig. 2 at 29, may have a re-entrant portion and which may also have an inwardly bent flange 30 along the free lower edge. Furthermore, also side walls 23,24, approximately at the level of the under-side of belt 21 , are provided with comparatively narrow depending flanges 31. The support rollers 22 are mounted between flanges 31 of the two side walls 23,24. The two side frame sections 26 are connected by cross bars. Fig. 2 shows, by way of example, such a cross bar at 32, which is provided between the inner surfaces of the vertical portions 28, in this example more in particular between the opposite re-entrant portions 29. Fig. 2 further shows at 21′ the return path of the conveyor belt. It is observed that the use of self-sustaining side frame sections bent from plate material highly simplifies the construction of the frame of a belt conveyor and hence the construction of a total conveyor. Moreover, the side frame sections, identical for both sides, can be manufactured and stocked in standard lengths of e.g. 2 meters and a conveyor of any desired length can be manufactured by attaching the required number of sections longitudinally to each other, e.g. by welding, possibly cutting the last section to the exactly desired length, installing the cross bars and subsequently mounting the support rollers. The side walls 23 or 24 and 27 of the triangular portions preferably are comparatively steep so that there is produced as it were an open-bottomed triangular beam section which does not require further internal reinforcements. If desired, the side frame sections can be constructed in such a manner that the contiguous ends can be inserted one into the other to some extent, in the manner of tent poles. The frame is then completed by attaching an end portion to each end. One of the end portions comprises a drive motor and the drive pulley and the other end portion comprises a return roller. The end portions according to the invention can be constructed as standard portions, in which case the two end portions of a belt conveyor may be identical. In this manner, it becomes possible to obtain a modular build-up of a belt conveyor of any desired length from a small number of standard parts. Moreover, a conveyor of this kind has a comparatively light weight and a comparatively low height transversely to the direction of transport. The re-entrant portions 29 on the one hand form a reinforcement of the side frame sections and on the other hand may serve as an outer guide or bearing for applications among other things in so-called horizontal conveyors such as duo extendable belts and the like. Such a carriage is mostly mobile and is provided with supports for the conveyor, which enable the conveyor to be brought from a horizontal position into a desired inclined position. In the example shown in Fig. 2, the portion of the side frame section situated underneath the portion 29, together with the lower flange 30 and the lowermost flange 33 of portion 29, forms a moulding being the mirror image of the moulding formed by the re-entrant portion 29. This moulding too, may serve as a guide for members, such as rollers or the like of a carriage, whether or not in combination with portion 29. For the sake of completeness, it is observed that the mouldings need not be exact mirror images of each other and further may have a form other than the form drawn. Additional mouldings may also be provided. Fig. 3 is a diagrammatic cross-sectional view of a telescopic conveyor according to the present invention, such as may be used in a telescopic low-bin filler. For the sake of elucidation, Fig. 3 diagrammatically shows at A the construction of a telescopic conveyor and III-III also indicates what cross section is shown at B. Fig. 3A shows a telescopic conveyor having an endless belt 40, which is passed around a drive pulley 41 and an end return roller 42. The belt further traverses an S-shaped path formed by two intermediate rollers 43,44. To extend the conveyor, the end return roller is moved to the right and likewise rollers 43,44 are moved towards one another so that the total length of the conveyor becomes longer, while the S-shaped path is shortened accordingly. The shortening of the conveyor takes place in an opposite manner. The cross section shown in Fig. 3B is taken on the line IIIb-IIIb in the region of intermediate rollers 43,44. Fig. 3b shows an extendable portion 50 of a telescopic conveyor. This extendable portion in this example is identical to the conveyor shown in Fig. 2, with the exception of the level of the return path 21' of the conveyor belt. This level is determined at the cross section shown by the diameter of the end return roller 42 and by the location of the intermediate roller 43. The same reference numerals are used for the various parts of the extendable portion 50 as in Fig. 2. Extendable portion 50, at the cross section shown, lies within the base portion 51 of the conveyor. Base portion 51, similarly to the extendable portion, consists of side frame sections connected by cross bars 52 and which each have triangular portion 53 open at the under-side, with obliquely inwardly extending walls 54, forming a guide for the side strips of the conveyor belt. Lower inner flanges 55 of the walls 54 carry the shafts for support rollers 57. Furthermore, there are provided obliquely outwardly extending walls 56, which terminate in a substantially vertically depending portion 56', which is again provided with a moulding by means of a re-entrant portion 58 and an inwardly bent lower flange 59. The cross bars 52 in this example are comparatively low, i.e. provided near the lower edge of the descending portions 56'. By virtue of such a construction, combined with a slightly broader construction of the side frame sections, sufficient space is obtained for receiving the extendable portion 50. As a result of the triangular form open at the bottom of the side frame sections, so that the side frame sections of the base portion and the extenable portion may telescope into each other in a simple manner, and because the shafts of the support rollers or other support members are mounted between moulded portions disposed on the inside of the triangular portions, support rollers 22 of the telescopic portion can be positioned directly underneath support rollers 57 of the base portion, as shown in Fig. 3. As a result, the conveyor belt has to bridge only a tiny difference in level in the transition region between the base portion and the extendable portion. The trough shape of the conveyor belt is substantially maintained thereby, so that the telescopic design of the conveyor does not adversely affect the transport capacity or hardly so. The moulding 28,29 of the extendable portion can now be used for guiding the same in the base portion. Fig. 4 is a side elevational view of a conveyor according to the invention, which is advantageously composed of standard parts. The conveyor shown in inclined position, as with a bin-filling conveyor, comprises a central portion 60 and two end portions 61,62. Central portion 61 is composed of a suitable number of standard lengths of side frame section and cross bars. Mounted on the ends are end portions 61,62, which are preferably identical. The end portions are connected to the central portion preferably for pivotal movement about a pin transversely to the transport direction. Fig. 4 shows the pivot pins at 63,64. Also shown in broken lines are the swung-down positions of the end portions after release of locking members, not shown, such as bolts. When either of the end portions has been swung down, or both end portions have been swung down, the conveyor belt hangs loosely around the support rollers and the drive pulley 65 shown in broken lines and the end return roller 66. In that position, the endless belt can be mounted with facility and all portions of the conveyor are readily accessible for maintenance and/or repair. The end portion 62 can also contain the drive motor. The drive motor may be positioned in the drive pulley 65. Furthermore, both end portions have slots 67 in the side walls, extending in the transport direction, which slots together with adjusting members not shown, enable a movement of rollers 65 and/or 66, so that the conveyor belt can be tensioned and centred in the direction of travel in a simple manner. Fig. 5 shows a variant of the conveyor shown in Fig. 4, with the upper end portion, indicated at 70, being constructed as a collapsing portion bringing the end of the transport path in a substantially horizontal orientation. The lower end portion 71 in this example is provided with a chute 72 for the products being transported and further includes a reinforcement 73 and a drawbar 74, so that the conveyor mounted on a mobile carriage, not further shown, can be coupled to a tractor. It is observed that after reading the foregoing, various modifications will readily occur to one skilled in the art. For instance, the side wall sections may have a shape deviating from that shown, in that e.g. a non-isosceles triangular section or a trapezoidal section are used. Such modifications are deemed not to depart from the scope of the present invention.

Claims: A belt conveyor, in particular suitable for vulnerable products, such as agricultural and horticultural products, comprising a conveyor belt (21) guided by two return rollers (41,42) and a plurality of support members (22;57); at least two hollow opposite side frame sections (26;26',53) bent from sheet material and open at the underside and each having a platelike portion which in cross-sectional view extends obliquely downwards from an upper ridge in the direction of the other side frame section and supports in use a side strip portion of the conveyor belt (21;40), said obliquely downwards extending platelike portion (23,24;54) at its lower end having a depending inner flange (31;55) facing a similar inner flange of the opposite side frame section, wherein the support members (22;57) are mounted between said inner flanges, characterized in that said side frame sections (26;26',53) each are completely open as viewed in longitudinal direction, and in that said platelike portions (23,24;54) of the side frame sections are steeply inclined and support the side strip portions of the conveyor belt in such a manner that side strip portions form side wall portions moving together with the bottom portion of the conveyor belt (21;40), which side wall portions reach up to near the upper ridges of the side frame sections. A belt conveyor as claimed in claim 1, characterized in that each side frame section (26;26',53) includes a descending portion (28;57) at the outer side facing away from the other side frame section, which descending portions (28;57) are provided with at least one longitudinal moulding (29;58). A belt conveyor as claimed in claim 2, characterized in that said descending portions (28) have a flange (30;59) formed along the lower edge and oriented towards the opposite side frame section. A belt conveyor as claimed in any one of claims 1-3, characterized in that each side frame section is cross-sectionally substantially triangular with an open base and an upwardly oriented apex. A belt conveyor as claimed in any one of the preceding claims, constructed as a telescopic conveyor having a base portion (51) and at least one extendable portion (50), and a belt (40) guided by a first return roller (41) at one end of the base portion, a second return roller (42) at the free end of the extendable portion and two rollers (43,44) at the adjacent ends of the base portion and the extendable portion respectively wherein the belt (40) follows an S-shaped path over and between said two rollers (43,44), characterized in that the base portion (51) consists of at least two opposite side frame sections (53,56') bent from plate material, which are connected by support members (57) for a conveyor belt (40) and by cross members (52), said side frame sections each being hollow and in use slidably receiving a corresponding similar but smaller hollow side frame section of the telescopic portion (50) bent from plate material, wherein the inner flanges (31) of the opposite side frame sections of the extendable portion (50) reach lower than the inner flanges (55) of the side frame sections of the base portion (51) in such a manner that the support members (22) of the extendable portion (50) are located directly underneath the support members (57) of the base portion (51) insofar as the extendable portion extends into the base portion. A belt conveyor as claimed in any one of the preceding claims, characterized by end sections (61,62;70,71) provided at the opposite ends of the conveyor, said end sections containing a drive pulley (65) and an end return roller (66), respectively, and each having a self-supporting frame made from sheet material, the frames of the end sections (61,62;70,71) being substantially identical. A belt conveyor as claimed in claim 6, characterized in that one end section (61,70) is constructed as a collapsing section. A belt conveyor as claimed in claim 6 or 7, characterized in that one of the end sections (71) is provided with reinforcing means (73) and a drawbar (74) connected thereto. A hollow side frame section bent from sheet material for a belt conveyor as claimed in any one of the preceding claims, said side frame section in the position of use being open at the underside and having an uppermost longitudinal edge, an inner flange (31;55) for supporting in use one end of a belt support member (22;57), characterized in that said side frame section (26;26',53) is completely open as viewed in longitudinal direction and comprises in the position of use a steeply inclined platelike portion (23,24;54) downwardly extending from the longitudinal edge to the inner flange (31;55), the frame section further having an outer descending flange (28;56') for supporting in use one end of a cross member (32;52) of the belt conveyor, said descending flange (28;56') being provided with at least one longitudinal moulding (29;58). A side frame section as claimed in claim 9, characterized in that the steeply inclined platelike portion (23,24;54) in use in a vertical cross section encloses an angle of 55° or more with the horizontal plane. A side frame section as claimed in claim 9 or 10, characterized in that the hollow side frame section in the position of use and above the inner and outer flanges (31;55 and 56' resp.) in cross section has the shape of a triangle.

Inventors: MIDDEL, JAN
Applicants: ZIJLSTRA & BOLHUIS B.V.
Application year: 1988
Main classification: B65G21
IPC codes: B65G21