JPS6065936A - Joining structure of high tension canvas layer for conveyor belt - Google Patents

Abstract

PURPOSE:To moderate concentrated stress directed toward a joining end part and thereby a high tension canvas layer from being separated by providing a cutway part in both parts of the high tension canvas layer joinned with each other and positioned on the outmost of a conveyor belt to form a bending rigidity reducing part. CONSTITUTION:A conveyor belt is formed by providing an intermediate rubber layer 13 and a cover rubber layer 14 among high tension canvas layers 12 formed by coating a fabric 11 with rubber coating and outside the canvas layers 12. In this instance, the joining part of the conveyor belt is formed by cutting the canvas layer 12 and the rubber layer 13 stepwise with a prescribed step length (l) taking the canvas layer 12 as a boundary, and arranging rubber 15 among surfaces of the adjoining canvas layers 12. Plural tanzaku-shaped cutaway parts 16 are provided on the both joining ends from which the rubber layer 14 is cut away for forming a bending rigidity reducing part 17. Thereafter, the joining parts are constructed by arranging a cover canvas 18 and a padding rubber 19 on the both parts 16, 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bonding structure for high-tensile canvas layers for a conveyor belt, and particularly to a bonding structure that effectively prevents peeling of the high-tensile canvas layer at a bonded portion of a conveyor belt.

As a conventional canvas layer joining structure of a bridle conveyor belt for small loads, there are those disclosed in, for example, Japanese Utility Model Publication No. 15168/1982 and Japanese Utility Model Publication No. 5426/1983. All of these are aimed at: 1) improving the flexibility of the conveyor belt by preventing thickness discrepancies due to mutual overlapping of the canvas layers, and increasing the adhesion area between the end surfaces of the canvas layers to increase the tensile strength. This invention relates to a joining structure in which a zigzag-shaped, strip-shaped, or other cut-out portion is provided at each end of a single canvas layer, and these cut-out portions are fitted and bonded to each other.

However, such known conveyor belts are designed for small loads with only a single layer of canvas buried within them, and have extremely low durability for conveying large objects.
Along with improvements in the material of the canvas layer, it is becoming common practice to embed multiple layers of canvas in the conveyor belt to manufacture conveyor belts that can withstand large loads, as shown in Figure 1. .

Here, in the illustrated example, the conveyor belt for Oumeju is made by forming a canvas layer 2 on a woven fabric 1 made of nylon fibers, for example, by coating it with rubber by dipping, and forming four layers of this canvas layer 2. are vulcanized and bonded to each other through the three intermediate rubber layers 8, and cover rubber shells are vulcanized and bonded to the outermost canvas layer 2, respectively.

In order to form the joints of the conveyor belt, first, each canvas layer 2 and intermediate rubber layer 8 are cut out in a stepped manner, for example, with a step length of 1 = 800 mm, with the canvas 12 as the boundary, and then these cut portions are The stepped surfaces are arranged opposite to each other and the adjacent general fabric layers 2.2
Preferably, the rubber 5 is arranged between the surfaces of each canvas N2.
Then, at the end portion of the outermost canvas layer 2 from which the cover rubber layer 4 has been removed, a presser canvas 6 and a padding rubber 7, which are also coated with rubber, are placed on the outer side. They are arranged sequentially, and finally, in addition to the step-like surface portions of the end portions of each canvas layer, the end portions of the outermost canvas layer 2, the presser canvas 6, and the padding rubber 7 are vulcanized and bonded to each other. ing.

Note that even in such a conveyor belt for heavy loads, as in the conventional one-ply conveyor belt described above, the end portions of the canvas layers 2 are prevented from overlapping each other, and
Of course, it is necessary to increase the adhesive strength of the canvas layer 2 to increase its tensile strength, but in this conveyor belt for heavy loads, multiple canvas layers 2 are buried, and the edges of each canvas layer 2 are buried. Since the parts are vulcanized and bonded to the surface of the canvas layer 2 that comes into instant contact via the rubber 5, sufficient adhesion of the canvas layer 2 can be achieved without having to bond the end surfaces of the canvas layers to each other as in the conventional monobly conveyor belt. It can bring strength.

Therefore, here, rather than the adhesive strength between the canvas layers,
Care should be taken that their end parts do not overlap, and for this reason, when the end faces of canvas layers 2 of the same level facing each other are spaced apart and their stepped surfaces are glued together, the rubber 5 can also fill the gap between those end faces.

Such a conveyor belt for heavy loads has sufficient durability against considerably large loads due to the fact that the canvas layer 2 has multiple layers and the material of the canvas layer 2 has been improved. can.

However, in the conventional canvas layer joining structure as shown in FIG. When the thickness of the canvas layer 2 is increased in order to provide durability against large loads, the bending rigidity of the canvas layer 2 also increases, and the conveyor belt wound around the pulley is bent and deformed by the pulley. At this time, there was a problem in that stress concentration occurred at the joint edge of the outermost canvas layer 2, and the canvas layer 2 peeled off from there at an early stage. That is, in the illustrated example of the joining structure, when the tensile strength per 1 cIn width of the canvas layer 2 is up to about 800 kg/crn, in other words, when the canvas layer has a tensile strength of up to about 1.2 cm, the Since the bending rigidity is not so high, the stress generated at the joint edge of the outermost canvas layer 2 is not so large, and therefore, peeling of the canvas layer 2 is not so much of a problem, whereas it can handle a larger load. Therefore, when the tensile strength of the canvas layer 2 is set to about 400 kg/cm or more, the tensile strength of the canvas layer 2 becomes about 1.5 kg/cm or more, and the bending rigidity and tensile shear stress of the canvas layer 2 become high. According to the structure shown, which does not take any measures to reduce the rigidity and shear stress of the joint end portion of the canvas layer 2, when the joint end portion is bent, the joint end portion 2 is bent. A significant reaction (4) as shown in (4) causes force concentration, and as a result, there is a problem in that the canvas layer 2 peels off from the joint edge relatively early.

The present invention advantageously solves the problems of the prior art and provides a high-tensile canvas layer bonding structure that sufficiently increases the durability of the conveyor belt against heavy loads.

The joining structure of the high-tensile canvas layer for a conveyor belt of the present invention is particularly characterized in that the outermost high-tensile canvas layer is provided with a cut-out portion such as a strip-shaped, mountain-shaped, or wave-shaped portion at both mutually opposing joint end portions. Alternatively, bending stiffness reducing portions formed by providing hole-shaped cut portions are provided symmetrically. Here, since the bending stiffness reduced portions of both joint end portions are symmetrical with each other, even if the end surfaces located on the same axis are butted together, the cut portions will not fit into each other. For example, the joint end portion of the outermost canvas layer is prone to bending due to the presence of the bending stiffness reduced portion, so it is especially important to use a high-tensile canvas layer made of thick twisted yarn or a high-strength canvas layer for conveyors for heavy loads. When constructing a belt, the concentration of stress on the joint end portion of the canvas layer is sufficiently relaxed, and peeling of the n1 high-tensile canvas layer is effectively prevented.

The present invention will be explained below based on the drawings.

FIG. 8 is a cross-sectional perspective view showing one embodiment of the present invention.

In the figure, reference numeral 11 indicates a woven fabric made of relatively thick twisted yarns, and by applying a rubber coating to this woven fabric 11, a high-tensile canvas layer 12E is constructed.

Further, 18 indicates an intermediate rubber layer provided between each high-tensile canvas layer 12, and 14 indicates two upper and lower cover rubber layers arranged further outside of the outermost high-tensile canvas layer 12.

Here, such a joint part of the conveyor belt is formed by cutting each high-tensile canvas layer 12 and the intermediate rubber layer 8 into a step shape having a required step length l with one canvas layer 12 as a boundary, and Preferably, the surfaces of the high-tensile canvas layers 12 are made to face each other with the step-like surfaces of the cut portions facing each other, and the rubber 15 is placed between the surfaces of the canvas layers that are in instant contact with each other, so that each canvas layer is preferably at the same level. 12. The end surfaces of 12 are butted against each other, and an interval is made in the width direction at both joint end portions of the outermost high-tensile canvas layer 12, in other words, at the portion where the cover rubber 14 of the canvas layer 12 is removed. By providing a plurality of strip-shaped cut portions 6 symmetrically with respect to the joint center line, bending stiffness reducing portions 17 are provided at both joint end portions, and furthermore, the bending stiffness reduction portions 17 are provided at both joint end portions. Then, the presser canvas [8] and the padding rubber 19 are sequentially arranged over both joint end portions, and finally, they are vulcanized and bonded to each other.

Incidentally, the pitch, width, and length direction dimensions of the strip-shaped cut portions 16 can be appropriately selected depending on the required reduction amount and required reduction length of the rigidity of the joint end portion.

According to such a joint structure, there is a bending stiffness reducing portion especially at the joint end portion of the outermost high-tensile canvas layer 12]7
By providing this, when the conveyor belt undergoes bending deformation, the stress generated at the joint end portion of the conveyor belt is reduced, as shown by the solid line in FIG. This results in sufficient flexibility of the joint end portion against bending, and therefore, it is effective to prevent peeling from the joint end portion of the high-tensile canvas layer 12, especially from the joint edge. This greatly improves the durability of the conveyor belt.

Also, although it is not clear from the illustrated example, the high tensile canvas layer 1
2. Presser canvas 18 placed further outside the joint end portion of 2.
It is also possible to provide cut-outs similar to those described above at both longitudinal ends of the presser canvas 18 - in such a case, sufficient flexibility is provided at the longitudinal ends of the presser canvas 18, and from there, The occurrence of peeling of the presser canvas] 8 is also effectively prevented.

FIG. 5 is a plan view showing a modified example of the stiffness reducing portion 17, and FIG. figure(
b) is achieved by providing a plurality of circular hole cutouts 16 (8) in the joint end portion near the joint edge, and Fig. 5 (○) shows that a plurality of round hole cut portions 16 are provided in the joint end portion near the joint edge. By providing the elongated hole cut portions 6, rigidity reducing portions 17 are respectively formed. In any of these examples, the joint end portion will have sufficient flexibility, so early peeling will be effectively prevented.

Although the present invention has been described above based on the illustrated example, it goes without saying that the number of layers of the high-strength canvas layer 12 may be a plurality of layers other than that shown in the figures. One or more oval holes, the number and shape of which can be adjusted as long as the desired effect is achieved;
It can also have a trapezoidal shape or other shapes.

Therefore, according to the present invention, in particular, bending stiffness reduced portions are provided symmetrically at both mutually opposing joint end portions of the outermost high tensile canvas layer, and the bending stiffness reduced portions By ensuring the flexibility of the layer, the concentration of stress on the joint edge is alleviated, effectively preventing the occurrence of peeling of the high-tensile canvas layer from there, and significantly increasing the durability of the conveyor belt. can.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional perspective view showing a conventional example, Fig. 2 is a line diagram showing stress concentration on the joint edge of the outermost canvas layer in the conventional example, and Fig. 8 shows an embodiment of the present invention. FIG. 4 is a cross-sectional perspective view, FIG. 4 is a line diagram showing the effect of stress on the joint end portion of the outermost high-tensile canvas layer in the joint structure shown in FIG. 8, and FIG. 5 is a plan view showing the bending stiffness reduced portion. be. ] 2... High tensile canvas layer 18... Intermediate rubber layer 14.
...Cover rubber layer]5...Rubber 16...Removed part 17...Bending stiffness reduced part 18...Presser canvas]
9...Buried rubber. Figure 1 Figure 2

Claims (1)

[Scope of Claims] L In a joint of a conveyor belt formed by embedding a plurality of high-tensile canvas layers, a cutout portion is provided at both mutually opposing joint end portions of the outermost high-tensile canvas layer. A joint structure of high-tensile canvas layers for conveyor belts, in which bending stiffness-reduced portions formed by this method are symmetrically provided.