JPS61136808A - Conveyor belt - Google Patents

Abstract

PURPOSE:To improve the coefficient of utilization of strength in a conveyor belt having a specific fabric core body, according to a method wherein a woof and a warp made of the yarn of an aromatic polyamide constructed by the specified upper, center and lower twisting three steps are arranged at straight- like position, being entwined by means of an entwining yarn to construct the core body. CONSTITUTION:A warp 1 consists of the yarn of an aromatic polyamide constructed by upper, center and lower twisting three steps. In this case, the angle across a center yarn 5 and the yarn axis of a lower yarn 4, or a center twisting angle alpha, is 10 to 30 degrees, and the angle across the axises of an upper yarn and the center yarn 5 is 10 to 20 degrees. The intertwisting number of the upper yarn is specified to two or three. The warp 1 and a woof 2 are arranged at substantially straight-like position, being entwined by means of an entwining yarn 3 to construct a core body. According to the above constitution, the core body having high coefficient of utilization of strength and high strength can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a conveyor belt having a core fabric having a thickness of 1M or more, and particularly to a conveyor belt having excellent strength and durability in the core fabric.

[Conventional technology]

Conventionally, a core fabric has been used as a reinforcing material for conveyor belts, but in order to improve the strength utilization rate, a special fabric with no shrinkage is used as the structure of the core fabric.

Figures 1A to 1C are diagrams for explaining special weaving, with warp threads 1
(used in the longitudinal direction of the belt) and the weft thread 2 are simply placed perpendicular to each other, and the warp and weft threads are not intertwined and woven together like in normal textiles.

In addition to the warp yarns 1 and the weft yarns 2, a leno yarn 3 is entangled with the weft yarns as shown in FIG. 1C to form a cloth-like structure. Therefore, warp thread 1
The weft threads 2 are substantially straight and in a so-called non-wavy state, and such weaving is referred to as special weaving in the present invention.

The material used for the warp thread of the special weave is ordinary vinylon,
Polyester, polyamide, etc. are commonly used, but recently aromatic polyamides have also come into use.

However, the structure of conventional special weaving is that the warp yarns are single-twisted or double-twisted using top and bottom twists, and the twist configuration of the warp yarns is also undefined (for example, 1500d x 2 x 6.150
0dx 3 x 4), and the twist angle was also inappropriate.

Therefore, the power utilization rate is low, and the high power (1000 to 250
Not only was it not possible to produce a core of 0 kg/am), it was also necessary to use a large amount of aromatic polyamide yarn, which was disadvantageous in terms of cost.

[Purpose of the invention]

The object of the present invention is to eliminate such drawbacks of the prior art and provide a conveyor belt having a core body with high strength and utilization.

[Structure of the invention]

That is, the present invention provides a conveyor belt having one or more layers of core fabric, which has a structure in which the warp yarns and weft yarns of the core fabric are substantially straight, and these are entangled with leno yarns. , and the warp yarn is (1) a plied aromatic polyamide yarn consisting of three stages of top, middle, and bottom twists, and (2) the angle between the axis of the middle twist yarn and the axis of the bottom yarn (hereinafter referred to as (3) the number of twists of the ply-twisted yarn; The gist thereof is a conveyor belt characterized by having two or three belts. 'Hereinafter, the present invention will be explained in detail by way of examples with reference to the drawings.

Figure 2 is a diagram showing the middle twist angle, where 4 is the first twist yarn (5 strands in the figure), and its hewax angle α is the following formula (1), (2
).

2r=KJD/ρ −−−−−−−−−−−−
------・(1) tan cx = 2 πr /
h −−−−−−−−−−−−−−−−−(21 here r: radius (wm), to: constant (0,011),
ρ: Specific gravity of woven fiber, α: Helix angle, h: Pitch (+n) of lower twist yarn, D: Denier of medium twist yarn.

FIG. 3 is a diagram showing the ply-twist angle, where 5 is a medium-braid yarn (3-bray in the figure), and the ply-twist angle β is determined by the following equation (3).

tan β= 2 tc R/H---------
--- (31 where R: radius (n+) of the upper yarn centered around the cord axis, H: pitch (m) of the upper yarn.

Figure 4 is a diagram showing the number of training stages and the number of upper training stages, a
1 indicates a lower-strand yarn, b indicates a medium-twist yarn, and C indicates a top-twist yarn. Therefore, in FIG. 4A, the number of twist stages and the number of final twists are both 1, in B, the number of twist stages and the number of final twists are both 2, and in C, the number of twist stages is 3. This is an example of four twists.

In the core in the present invention, it is necessary to use aromatic polyamide for the warp threads.

Usually, the cutting strength of twisted yarn is determined by the strength of the material used for it. That is, if the strength of the material is high, a twisted yarn with high strength can be obtained.

However, there are some cases in which the inherent strength of the fiber cannot be fully utilized unless the fiber material is configured appropriately based on the shape of the stress-strain curve. A typical example is aromatic polyamide 1'' (for example, "Kevlar" (trademark)).

Figure 5 shows nylon (N) and polyester (PUT).
) The stress-strain curve of Kevlar (K) is shown. As seen in the graph, although Kevlar has high strength, its elongation at break is lower than that of polyester or nylon.

If you pay closer attention, the modulus near the cutting point is small for polyester and nylon (a horizontal curve), but for Kevlar it is large, and the stress-strain curve is almost linear from the initial stage to the cutting point. It has become.

The modulus near the cutting point is called the terminal modulus, and in general, fibers with a small terminal modulus have a high strength utilization rate, whereas Kevlar is the complete opposite, so it is necessary to carefully consider the structure of the twisted yarn.

Kevlar can also be said to have terminal modulus due to its low elongation. Polyester and nylon have a low terminal modulus, so the twist structure does not significantly change the strength utilization rate.

On the other hand, the special fabric used for the core of the present invention has warp threads and weft threads that intersect in a straight line, and the warp threads and weft threads are bound together by leno threads, so they are similar to ordinary plain weave or twill weave. Since the warp threads are not crimped, the loss of strength due to friction between the warp threads and the weft threads is small, and the strength utilization rate hardly changes depending on the material of the weft threads.

Therefore, other organic synthetic fibers can be used for the weft in the present invention.

Only when the special fabric used as the core of the present invention satisfies all of the following four items will it exhibit a high strength effect.

(1) The angle is 10 to 30''.

(2) The top combustion angle is 10 to 20 degrees.

(3) The thread consists of three tiers.

(4) The number of ply twists is 1 or 2 or 3.

In the present invention, the high-strength twisted yarn refers to one whose cutting strength divided by the total denier of the twisted yarn (g/d) is 16.5 g/d or more.

Examples will be used to explain how the strength decreases and it is economically disadvantageous if the above (II to (4)) are not satisfied at the same time.

What I would like to clarify here is that the four factors mentioned above interact with each other to produce a synergistic effect in the twisted yarns that make up the fabric of the present invention, which achieves maximum strength with a small amount of yarn, and these four factors do not work independently. It has no effect on strength. Furthermore, the total denier of the single threads constituting the fabric of the present invention is 10,000 d.
Thick twisted yarns as mentioned above exhibit great effects and are economically advantageous.

(Example) Using "Kevlar" as the warp yarn, special fabrics were made by changing the number of twists, number of twists, and twisting angle, and their strength was measured, and the results shown in the table below were obtained. All yarns were 1500
d (1000 filaments).

(Margin below this page) Comparing 11h3 according to the present invention and 11h14 according to the conventional method, the middle twist angle of the former is 26.83°, while the latter is 33.67°, and the latter has a twist angle of 30°. It can be seen that it exceeds. It is generally known that the larger the angle, the lower the strength, and it can be understood that the angle of medium twist, which is one of the conditions of the present invention, must be 30 degrees or less.

On the other hand, when comparing other items, the ply twist angle is 1 for both.
The same as 9.5°, the number of twisting stages is 3 stages, upper, middle, and lower, and this is also the same, but the upper number is 1, but the number of twists is 2 in the former.
In contrast, the latter was 4.

Therefore, the difference between Magnetic 3 and N[Li2 is the two-term difference between the middle twist angle and the number of top twists, but what should be noted here is the middle twist angle and the number of top 1 twists, as mentioned above. The numbers influence each other. It can be clearly understood that the medium twist angle is responsible for a portion of the overall effect.

Next, when considering the final twist angle, the influence of the final twist angle can be clearly seen by comparing 11h2 according to the present invention and Na13 according to the conventional method. As with the middle twist angle, there is a synergistic effect between the final twist angle and the number of final twists, and as the twist angle increases, the strength decreases, and you can understand why the angle must be appropriate.

Next, the effect of three-stage twisting, which is one of the features of the present invention, is clearly seen in the comparison between the 11 examples in the table and the conventional method 7111. According to the present invention, even if the total number of twisted yarns varies widely from 9 to 15, the strength is 16°5 to 18.1.
It shows a very high intensive utilization rate of g/d. On the other hand, in the conventional method, the utilization rate is 12.3 to 15.0 g/d, which is significantly lower.

Here, the conventional method 11m13.14 shows low strength even though it is twisted in three stages, but as mentioned above, the utilization rate is decreasing because four factors influence each other. . Both the twist angle and the number of top twists have a negative influence on the strength. This shows that if the twist angle is too large (or the number of first twists is too large), the positive effect of three-stage twisting is completely negated, and the strength is significantly reduced.

Furthermore, although it is possible to increase the number of twisting stages to four or more, it requires a lot of man-hours and is disadvantageous in terms of cost, and a large number of stages at the ti end becomes impossible due to equipment considerations, which is not beneficial.

Furthermore, when we pay attention to the effect of the number of ply twists, this factor has the greatest effect on strength, and as seen in the examples in the table,
There is a large difference in strength between the present invention and the conventional method. In particular, the conventional method N11L13°18 is an extreme example of the number of upper twists. Seed 13 has 6 strands, Toru 18 has 1 strand, and the strength will decrease if the number of upper twists is too large or too small.

As I have stated many times before, it should be kept in mind that in addition to the number of twists, the angle of the top twist for N1113, the angle of the middle twist for N[Li2, and the number of twist stages have negative effects. Must be.

In addition, the number of upper twists in space 17 is 3, but the weight is 13.6 g/
d and low strength. The reason for this is that the number of stages among the four factors is 2, so this factor acts as a large negative effect,
The strength has decreased.

〔Effect of the invention〕

Since the present invention is configured as described above, it has the following effects. That is, (1) A durable conveyor belt can be obtained because a high strength utilization rate and a highly strong core body can be obtained.

(2) Achieving the desired strong design.

(3) The cost of the core is low, which is economically advantageous.

[Brief explanation of the drawing]

Fig. 1 is an organization chart of the special weave, Fig. 1A is a plan view, Fig. 1B is a front view, Fig. 1C is a side view, Fig. 2 is an explanatory diagram showing the medium twist angle, FIG. 3 is an explanatory diagram showing the twisting angle, and FIGS. 4A and B. C is an explanatory diagram showing the number of twist stages and the number of upper twists, and FIG. 5 is a graph showing a stress-strain curve. 1--Warp thread, 2-Weft thread, 3-Leander thread, 4-Low twisted thread, 5-.-Medium twisted thread.

Claims (1)

[Claims] A conveyor belt having one or more layers of core fabric,
The core fabric, the warp yarns and the weft yarns are substantially straight, and have a structure in which these are entwined with leno yarns, and the warp yarns have (1) three stages of upper, middle and lower twists; (2) The angle between the axis of the middle strand and the axis of the bottom strand is 10.
-30°, the angle between the axis of the ply-twisted yarn and the axis of the medium-twisted yarn is 10-20°, and (3) the number of twists of the ply-twisted yarn is 2 or 3.