RU29374U1 - DEVICE FOR DETERMINING THREAD RIGIDITY IN A BEND - Google Patents

Abstract

A device for determining the bending stiffness of a thread, comprising a strain gauge measuring the tension of the driven branch of the thread, a cylinder of known radius, characterized in that it is equipped with a stepper motor moving the carriage with a strain gauge interacting with the thread, a photosensor that fixes the moment the thread moves on the cylinder and a video camera for taking an image placed opposite the cylinder.

Description

The utility model relates to the textile industry, namely, devices designed to determine the stiffness of a thread in bending.

The following devices are known for determining the stiffness of a thread during bending: ПЖУ12М 1, containing a base, a lifting mechanism with a movable clamp for an elementary sample, a loader, force and strain gauges for an elementary sample; PT-2, containing the supporting horizontal platform, consisting of a fixed middle part and movable lateral sides, a mechanism for smooth and uniform lowering and lifting of both sides of the horizontal platform, deflection indicators, absolute deflection flange, load.

A disadvantage of the known devices is that when calculating the bending stiffness of the thread proceed from the condition of pure bending, excluding any phenomena associated with bending. The phenomenon of pure bending is practically absent during the processing of textile yarn. For example, bending during knitting is accompanied by friction and stretching.

As the closest analogue, we took a device for determining the bending stiffness of textile materials 2, containing a coiling unit, strain gauges measuring the tension of the driven and thread branches, and frames for attaching removable rods. The tension of the filament branches is recorded using an ANCH7M strain gauge 8 and an H327 recorder.

A disadvantage of the known device is the low accuracy of the measurement due to the fact that the actual angle of the thread of the cylinder, the actual radius of curvature of the thread are taken constant.

The problem to which the invention is directed, is to increase the accuracy of measuring the parameters of the bending of the thread for the subsequent calculation of the stiffness of the thread in bending.

The specified technical result is achieved by the fact that for measuring the tension in the branches of the thread, the actual radius of curvature of the thread, the actual angle of the thread of the cylinder, a strain gauge, a photo sensor, a stepper motor, an amplifier, an analog-to-digital converter, a computer, and an image pickup device are used. The actual angle of the thread of the cylinder with a sufficient degree of accuracy can be fixed only at low loads on the thread. Based on the measured parameters, constant friction parameters are calculated, and then the bending stiffness of the thread.

In Figl shows a kinematic diagram, Fig.2 shows a structural diagram of the inventive device.

Based on (Fig. 1), a loading unit is installed, the construction of which includes a stepper motor (1), the output lever of which reports a reciprocating movement in the vertical plane of the carriage (2). The strain gauge (3) has free movement in the horizontal plane relative to the axis (4) of the carriage (2). A clamp (5) for the thread is attached to the end of the strain gauge (3). A cylinder of known radius (6) and a photosensor (7), including a photodetector and a light emitter, are mounted on a vertically located support. A video camera (8) is installed opposite the cylinder.

The device operates as follows.

The branch (9) of the thread (Fig. 1), enveloping the cylindrical guide (6), is inserted into the clamp (5) located on the movable strain gauge (3), which perceives the change in the tension of the thread with high accuracy. Branch (10) is loaded with a constant initial weight. A flag (11) is attached to this branch, tucked into the photosensor (7).

By the signal of a special program, the stepper motor (1) is turned on and the carriage (2) moves down evenly. The movement of the elements (2), (3), (4), (5) (Fig. 1) of the loading unit (NU) (Fig. 2) causes tension in the branches of the thread, which is recorded using an amplifier (U) and an analog-digital converter ( ADC) on a hard medium. Using special software, the movement of the thread is detected by the photosensor signal and a command is issued to record the tension G2 in the thread branch (10) (Fig. 1) and the image of the position of the thread on the cylinder. From the obtained images, the actual radius (g) of the thread is measured and the actual angle of the cylinder thread (a) is determined.

During the experiment, the initial load (Gi) is changed in a range that allows to determine (a) with sufficient accuracy. The bending stiffness of the thread for small and large loads is calculated using the dependence:

) l.

5

where Pi is the radius of curvature of the thread;

,

R is the radius of the cylinder;

i is the number of experiments,, 2, 3 ..;

FO, fi) are the constant friction parameters.

The results of determining the bending stiffness at low and high loads for threads of different linear densities are presented in the table.

(1)

The proposed device has the following advantages:

-increases the accuracy of measurement of parameters characterizing the bending of the thread, through the use of a stepper motor; a photosensor that fixes the moment of movement of the thread on the cylinder; camcorders for taking images.

-increases the reliability and objectivity of assessing the stiffness of the thread during bending due to the maintenance of friction parameters characterizing its behavior during bending in real conditions.

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Claims (1)

A device for determining the bending stiffness of a thread, comprising a strain gauge measuring the tension of the driven branch of the thread, a cylinder of known radius, characterized in that it is equipped with a stepper motor moving the carriage with a strain gauge interacting with the thread, a photosensor that fixes the moment the thread moves on the cylinder and a video camera for taking an image placed opposite the cylinder.