JPS627415B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of joining ends of a conveyor belt in which a plurality of layers of canvas are embedded in rubber as tensile members.

Conventionally, the method of joining rubber conveyor belts in which one or more layers of canvas are buried as tensile material is to remove the cover rubber at the top and bottom of both ends of the belt by a predetermined length necessary for joining to expose the tensile canvas. After cutting and removing the canvas layer in steps to a predetermined length, the opposing canvas tips are butted together with unvulcanized rubber interposed between each ply, and the reinforcing canvas layer is placed on top and bottom of the outermost ply joints. The commonly used method was to place a predetermined amount of unvulcanized rubber on top of the unvulcanized rubber, pressurize it from the outside, heat it, and join it together. In both methods, the canvas is cut at right angles to the thickness direction, and the ends of the canvas cut at right angles are butted and joined, so when the belt is bent, especially when the pulley diameter is small, bending stress is applied to the butt part of the canvas. There was a problem in that the upper reinforcing fabric was damaged due to the rise of the canvas, causing cracks in the cover rubber and causing premature failure of the belt.

In view of the drawbacks of the conventional method, the present invention aims to improve the method by forming tapered tip portions at both ends of only the outermost layer of ply canvas that is bonded to the upper and lower cover rubbers among the tensile canvas layers. By performing butt jointing, the bending stress at the joint is dispersed and relaxed, and the purpose is to prevent damage to the reinforcing fabric and cracking of the cover rubber.

That is, the feature of the present invention is that when joining the ends of a conveyor belt in which a plurality of tensile fabric canvases are embedded in rubber, the cover rubbers on the upper and lower sides of both ends of the belt are cut and removed by a predetermined length. exposing the layers, sequentially cutting and removing each tensile layer by a predetermined length to form a step-like joint; A vulcanized rubber sheet is interposed in a step shape and butted together, and the tips of both ends of the upper and lower outermost ply canvas are formed into a tapered shape and abutted, and an adhesive is applied to the tapered portion and the exposed portion of the canvas. drying, interposing an unvulcanized rubber sheet in the tapered abutting portion to cover it with a reinforcing canvas of a predetermined size, and filling the upper and lower surfaces of the joint with a predetermined amount of unvulcanized rubber and vulcanizing it from the outside. The bonding method consists of the steps of pressure, heating and bonding.

Hereinafter, the conveyor belt joining method according to the present invention will be further explained in detail with reference to the accompanying drawings.

First, FIGS. 1A and 1B show the respective ends of the conveyor belt to be joined, and in the same figures, 1, 2, 3 and 1', 2', 3' are usually the thicknesses after hot stretching and adhesive treatment. Tensile canvas made of 0.9 to 2 mm nylon, polyester, vinylon canvas, or a mixture of these canvases, and 5 and 6 are NR (natural rubber), SBR (styrene-butadiene rubber), CR (chloroprene rubber), NBR. The upper and lower cover rubber layers are made of a single material such as (nitrile rubber), IIR (butyl rubber), EPR (EPM (ethylene propylene monomer) or EPDM (ethylene propylene diene monomer)) or a blend thereof, and this cover rubber layer 5 , 6, the canvases 1, 2, 3 and 1'2',
3' are laminated, and three plies are buried in the figure. In this case, when burying the canvas, the side of the belt may also be buried, or, as shown in the figure, the canvas may be buried exposed on the side of the belt.

For the belt configured as described above, first, one end A is connected to the upper and lower cover rubbers 5 and 6 by a length l ₁ and l ₂ necessary for joining, and the other end B is
The layers are also cut and peeled off by the required lengths l ₂ and l ₁ , respectively, to expose the upper and lower tensile canvas layers 1, 3, 1', and 3' laminated.

Next, the canvas fabrics 1 and 2 at one end A and the canvas fabrics 3' and 2' at the other end B are sequentially cut and removed by a predetermined length to form a step-like joint at the portion. The manner in which the canvas layer is formed at this time is the most important point of the present invention. The tips of the canvases 1, 3 and 1', 3' forming the outermost plies of the first and third plies, which are directly bonded to the rubbers 5, 6, are tapered toward the ends by means such as buffing. Form into a tapered shape with an angle of ~20°. Therefore, at this time, 1
The slope of the tip of the canvas layer of the first ply and the slope of the canvas layer of the third ply are opposite as shown in the figure. Next, an adhesive such as rubber glue is applied to the exposed tapered portion and other flat portions of the tensile canvas layer and dried, and then rubber glue is applied again and dried.

The joint between both ends A and B thus formed is the second
As shown in the figure, unvulcanized rubber sheets R are interposed in steps on the upper and lower surfaces of the intermediate ply layer canvases 2 and 2', and the tips of the canvases facing each other, i.e., 1, 2',
1', 2, 2', and 3, 3' are butted against each other to form a joint.

At this time, the tips of the intermediate ply layer canvas 2, 2' are cut at right angles to the canvas thickness direction as in the conventional method, so they are butted together at right angles, but the outermost layer plies 1, 1', 3, 3 Since the tips of ' are formed in a tapered shape, the respective abutting parts form triangular grooves G and G' as shown in the figure.

Of course, the tapered tips of the outermost layer of ply canvas do not necessarily have to be brought into contact and abutted, but are butted at a slight interval so as to form a trapezoidal groove at the abutting portion, although not shown. It's okay.

Next, after the above-mentioned butt is completed, unvulcanized rubber sheets 5'' and 6'' are covered on the upper surface of the outermost ply joint, and a reinforcing canvas of a predetermined size, usually weighing 50 to 100 kg, is placed on top of the unvulcanized rubber sheets 5'' and 6''. Cover with low-strength canvas T, T' of /cm ply. Finally, the upper and lower joint recesses are filled with a predetermined amount of unvulcanized rubber 5', 6' necessary to obtain a flat joint at the joint, and the inside is filled with steam, an electric heater, or other vulcanized rubber. Using press plates P and P' equipped with a mechanism, the joint surfaces are pressed and heated from the upper and lower surfaces as shown by the arrows to perform a vulcanization press.

In this way, the unvulcanized rubber 5', 6' on the joining surface, the unvulcanized rubber sheets 5'', 6'' inside thereof, and the unvulcanized rubber sheet R of the intermediate ply layer are vulcanized, and both ends of the belt are cured. As shown in FIG. 3, the triangular grooves G and G' at the abutting portions of the outermost plies are filled, and reinforcing canvas T and T' are buried in between to form an integrated flat joint.

The above method is for joining multiple plies of tensile canvas layers, but even in the case of one ply, the exposed tip of the canvas is formed into a tapered shape as described above, and the so-called lamination method is used to overlap the canvas layers. After filling the upper and lower joint recesses with unvulcanized rubber, the joints are similarly pressed and heated to form a flat joint similar to the case of the multiple ply. .

Further, the above-mentioned joining method of the present invention relates to a rubber belt,
Although it has been described above, it goes without saying that the present invention is not limited to this and can also be applied to joining resin belts.

As described above, in the method of the present invention, a predetermined length of the upper and lower cover rubbers at both ends of the belt to be joined is removed to expose the tensile canvas layer, the exposed canvas layer is formed into a step shape, and the outermost layer is The tips of the ply canvas are formed into a tapered shape and butted together, and the tapered abutting portion is sequentially laminated and covered with an unvulcanized rubber sheet and a reinforcing canvas.After that, the joining recess is filled with unvulcanized rubber and pressurized. By applying this method, various effects as described below can be achieved.

(1) The outermost plies at the joint are tapered and butted, and the triangular grooves in these butts are filled with rubber, so when the belt bends, bending stress is not concentrated at the butt but is dispersed to the tapered part. As a result, the belt's flexibility is significantly improved and it can be used even with small pulley diameters.

(2) Due to the reason mentioned in (1) above, it is possible to prevent damage to the reinforcing fabric and cracks in the cover rubber due to the rising of the tensile canvas at the joints, especially for heat-resistant conveyor belts where the cover rubber deteriorates rapidly due to high-temperature loads. It is suitable as a joining method.

(3) Due to the reason in (1) above, the life of the joint can be extended, and the repair work of the joint, which has often been done in the past, can be significantly reduced.

(4) Since the reinforcing canvas is embedded in the abutting portion, the reinforcing effect in this portion is good, and together with the above effects, it is possible to further increase the life.

(5) Since the unvulcanized rubber sheet is interposed in the form of a step, it is suitable for dispersing bending stress at the canvas layer joint part, improving belt flexibility, and also improving the fit of the canvas layer at the joint part, further enhancing the joining effect. can be increased.

[Brief explanation of the drawing]

FIG. 1 is a partial side view showing the canvas exposure cutting mode of the joining method of the present invention, FIG. 2 is a partial side view showing the joining mode of the present invention, and FIG. 3 is a belt joint obtained by the joining method of the present invention. FIG. A, B...Joining belt end, 1, 2, 3,
1', 2', 3'... Tensile canvas, 5, 6... Cover rubber, R, 5'', 6''... Unvulcanized rubber sheet,
5', 6'...Unvulcanized rubber, T, T'...Reinforced canvas.

Claims (1)

[Scope of Claims] 1. A conveyor characterized in that the following steps (a) to (f) are performed in that order in joining the ends of a conveyor belt in which multiple layers of tensile canvas are embedded in rubber. How to join the belt. (a) A process of cutting and removing a predetermined length of the upper and lower cover rubber of both ends of the belt to be joined to expose the tensile layer at each end. (b) Each exposed tensile layer is covered with a predetermined length;
A process of sequentially cutting and removing to form a step-like joint. (c) Of the step-shaped tensile layer, an unvulcanized rubber sheet is applied in a step shape from the exposed upper surface of the canvas of the intermediate ply layer, and both ends of the upper and lower outermost ply layers of the canvas are abutted, respectively. A step of forming a tapered shape and abutting the two end portions against each other to form a triangular groove in the abutting portion. (d) A step of applying adhesive to the tapered portion and the exposed canvas portion and drying it. (E) A step of interposing an unvulcanized rubber sheet to the tapered end butt joint to cover the required reinforcing canvas. (f) A step of filling the upper and lower surfaces of the butt joint portion with a predetermined amount of unvulcanized rubber, applying pressure, heating, and joining.