SU1723222A1 - Braided cord - Google Patents

Abstract

Use: for traction devices. SUMMARY OF THE INVENTION: The cord is made of several strands forming the core and braided around the perimeter of the strand, wherein the ratio of the product of the diameter of the strands by their number to the diameter of the core is within 2.8-3.5, and the pitch of the braid is the case of the formula t yi0 + 0,318 Kdo К dl where t is the braid pitch; K (dc + do) 2 the number of braid strands; do is pt diameter; dc is the diameter of the core. 2 ill., 1 tab.

Description

The invention relates to the design of long products intended for traction devices, in particular, in agriculture and in the fishery.

A cord obtained by braiding strands (cables) forming a core, in which a complete overlapping of the surface of the core is made, and the braiding pitch is determined according to the dependence.

t ad K

Р1 cos a where t is the pitch of the sheath, mm;

a - the number of pairs of spindles on the machine;

d is the diameter of the thread, mm;

K is the number of filaments in the strand;

a - the angle of the weave.

The density of the braid is calculated by the formula

one

l: D sin a where D is the diameter of the braid, mm ..

However, in the well-known cord with the core, providing for complete closure

braided core, does not take into account the effect of braid on the core, the strength of which when forming from several strands largely depends on the degree of their compaction.

In the known cord, the dense braid, which completely covers the core, does not allow to create sufficient pressure on it and to provide a high degree of strength of the core, and also creates an increased consumption of the thread for the braid.

The aim of the invention is to improve the physico-mechanical properties of the cords.

The goal is achieved by the fact that in a braided cord made of several strands forming a core braided around the perimeter by strands consisting of one or several mono- or complex yarns with a pitch of braid ensuring complete overlapping of the core, the ratio of the product of the diameter of the strands their number to the diameter of the core is in the range of 2.8 to 3.5, and the pitch of the weave is determined by the formula

N

J

M

to with

N Yu Yu

t 0,318Kdo 10 +

TO

dS

(dc + do) 2 where t is the pitch of the weave, mm;

K is the number of braid strands (machine class);

do is the diameter of the strand (thread), mm;

dc core diameter, mm

This embodiment of the cord provides an improvement of its physico-mechanical properties.

Fig. 1 shows schematically the position of the braid threads on the core surface in a section plane perpendicular to their axes: a, biv with full overlap; g - with incomplete overlap of the core; FIG. 2 shows a part of the sweep of the braid and a sweep of the braid of the cord.

The cord is obtained as follows.

For the given strength of the cord, with the selected class of braider, the required number of core strands is prepared and its diameter dc is determined. Next, the braid strands are produced in such a way that the ratio of the production of the diameter of the strands by their number to the diameter of the core is within 2.8-3.5. The above step determines the weave pitch, installs it on the machine, and the braiding process is carried out.

To obtain comparative data, the weaving process was carried out at a ratio Kdo / dc in the range 2.5-5.0.

The physicomechanical indicators of the cords worked are given in the table.

The calculated breaking load of the cords, given in the table, was calculated as the sum of the breaking loads of the initial strands (cabol), taking into account the complete realization of the strength of the filaments.

As follows from the table, the best physicomechanical indicators have cords with the ratio of the product of the diameter of the strands by their number in the braid to the diameter of the core in the range of 2.8-3.5 (figure 1). The above weaving ensures the maximum strength of the core yarns with complete overlapping of its surface, which is not disturbed when the cord is bent through a rod 5 mm in diameter (+).

An analysis of cord samples of known construction showed that the ratio of the product of the diameter of the strands to their number in the onlet to the core diameter Kdo / dc, as a rule, is outside 4.0 and the degree of realization of the strength of the elementary threads in them does not exceed 70%. In addition, with the increase in the specified ratio

weave spacing decreases, i.e. increases thread consumption for braid.

It is also seen from the table that at the values of the ratio Kdo / dc 2.8, the (-) braid is broken in the process of bending the cord, which is a consequence of its structure.

With complete overlapping of the core surface with braid threads in a known cord, an ellipse, conventionally representing the cross section of a braid consisting of multifilament yarns, is positioned so that its major axis is perpendicular to the plane of the braid sweep (Fig. 1a). The / dc cross section of the braided strand is changed by increasing the small axis of the ellipse and passes through a circle (Fig. 1b) to an ellipse with a major axis parallel to the plane of the unfolding of the braid (Fig. 1c). It should be noted that the cross section of strands consisting of complex filaments in the form of a circle at Kdo / dc 3.14 conditionally shows the equality of the major and minor axes of the ellipse. A further decrease in this ratio first leads to an increase in the major axis of the ellipse of the spur section, and then to the formation of gaps (Fig, 1 g), i.e. the core partially opens and at the same time the degree of realization of the strength of the filaments falls.

In order to find the conditions for the complete closure of the yarns of the core surface, we construct a sweep of the braid (see Fig. 2).

The following notation is taken:

h DE is the pitch of the braid (the distance between the axes of adjacent strands of the same direction along the axis of the cord);

jrdc AC is the circumference of the core;

t BC is the pitch of the weave (pitch of the helix pd);

I DM is the distance between the axes of adjacent strands of the same direction along the normal to them;

dc - core diameter;

do is pt diameter;

K-class machine (the number of strands);

P is the angle of the helical braid of the braid.

With a dense packing of strands consisting of complex textile yarns, the pitch of the weave approaches the value of d0K, although it never reaches it. In deriving the formula, the equality t doK was adopted, the validity of this assumption was confirmed by the results of the experiment. Of

similar to the triangles abc and dem find that

L V2

do K,

 (dc + d0j

h J / l2 (do) 2 + i

2do rdc

Received in consideration that we will receive:

1 0,318ikok / l2 +

t

hK

H2 1/2 do K.

(dc + do) 2 Comparison of calculated and obtained braid pitch showed that. greater convergence of these quantities is observed if the number 10 is taken in the radical expression instead of m2. In this case, the equation takes the form:

t 0,318 +

do K2

(dc + do) 2

P p and m e p 1. A cord with a core with dc 3.60 mm and a do 0.7 mm was made on a 16th class braider, i.e. K 16.

; 3.1 (2.8-25 recommended

15 20

According to the above formula

t 14.6 mm.

A pitch of 14.5 mm was taken. The test results of the cord are shown in the table.

PRI mme R 2. The cord has the parameters: dc 3.29 mm; do 0.7 mm; K 16.

do k

25

 3.4

ZG

t 15.1 mm.

With the received braiding step t 15 mm 5 a cord was obtained, the test results of which are shown in the table.

The cords of the proposed construction have the ability to work for a long time, subjected to multi-cycle bends 10 and abrasion, and in some cases can replace steel ropes with increased consumption of materials, and at the same time eliminate the risk of injury.

Claims (1)

Claim 15 Braided cord made of several strands forming a core, braided around the perimeter of the strand, consisting of one or several mono- or complex threads with a pitch of braid, which ensures complete overlapping of the core, about t and h so that, in order to improve its physical and mechanical properties, the ratio of the diameter of the strands by their number to the diameter of the core is in the range of 2.8 to 3.5, and the braiding pitch is determined by the formula t 0.318 "do„ (dc + dc; 30 where t is the plexus pitch, mm ;. K is the number of braid strands (machine class); . do is the diameter of the strand (thread), mm; dc - core diameter, mm. ) 2 4fer / 776-vertm olmetto Sweep pr di Uig.2 Editor M. Tsitkina Tehred M. Morgenthal Order 1047 CirculationSubscribe VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, 4/5 Raushsk nab. Proofreader N. Revska