FI56590C - FOERFARANDE FOER MAETNING AV UNDER STICKNINGSSTEGET PAO EN NAOLSPETS I MASKINEN INRIKTADE KRAFTER OCH ANORDNING FOER ATT UTFOERA FOERFARANDET - Google Patents

Description

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* (44) Date of Nihtivikslpanon and other monthly publications. - Λ _Λ

Patent- och reglsterttyrelsen v 7 An * ökan utlagd och utUkrlfwn publlc * r »d 31.10.79 (32) (33) (31) Privilege requested — Begird pylorltet (71) (72) Iija Sisko Pietikäinen, Rauduntie 11 H, 02130 Espoo 13,

The present invention relates to a method of measuring to measure the forces on the needle head and a device to perform the method.

The strain on the yarn during the knitting phase varies depending on the characteristics of the yarn used, the structure and settings of the machine used, the structure of the knit to be made, and environmental factors.

Yarn strain, tension, describes the ease of knitting. If the strain is small, knitting is easy and machine downtime is low, and vice versa.

Various devices have been built to measure the ease of knitting. A sensitive device for measuring the torque of the machine is built on the drive shaft of a small-cylinder machine. The result obtained by mathematical means can be converted into the work required for knitting yarn / Textile Research Journal, Vol. 37 (7), 1967 p. 539 /.

The result given by that device is total. It does not provide information on the tension variations of the yarn in the knitting stage, nor on the tension peaks, the latter of which are important for the efficiency of knitting. The same is the case in a solution where all the pieces of one lock are attached to a measuring sensor / Journal of the Textile Institute, Vol. 61 (7), 1970 p. 340 /.

Due to the shortcomings presented, various devices have also been designed to measure the forces applied to a single needle.

The measuring strips acting as a sensor are placed between the head and the base of the severed needle so that the impulse generated by the force on the needle end is transmitted through the strip to the needle head / Wirkerei- und Strickereitechnik, Vol. 1B (6), 196Θ p.309 /. The design of the device is such that it can only be used on coarse-grained (3 gg) flatbed machines.

Several solutions are based on measuring the forces from the needle to the locking pieces. In one solution the knitting piece of the lock is attached to the force sensor / Textile Research Journal, Vol.38 (6), 1968 p.592 /, in the other the knitting piece is attached to the sensor and the guide lock piece below it / Journal of the Textile Institute, Vol.67 (4 ), 1976, 113 /. These devices can be used to study the forces acting on the locking pieces from a single needle when a new groove is built in the machine on the needle bases, where the locking pieces with a sensor guide the needle under test. The bases of all other needles run in a different groove.

A device has also been made in which part of the knitting piece has been replaced by a beam attached to a measuring sensor / Sen-I Gakkaishi, Vol.24 (2), 1968 p. 18 /.

In order to determine the strain on the yarn during the knitting phase, the distance between the measuring point and the object to be examined is large by means of the forces applied to the lock. Therefore, in addition to the forces acting on the needle head, several other factors are involved in the result.

The latest solution for determining the knitting tension of a yarn is probably a device in which the upper part of the needle wall has been replaced by a plate attached to a force transducer / Journal of the Textile Institute, Vol.67 (4), 1976 p. 119 /. The method is only applicable to machines with a single needle system. It can be used to measure the forces exerted from the wire on the top edge of the groove wall when the needle is depressed.

The share of information from the yarn forming the new loop in the results is small.

It is an object of the present invention to avoid the limitations and drawbacks of the above solutions. To this end, a method has been provided by the invention, which is characterized in that 3,56590 measurement results are obtained which have few other influencing factors in addition to the forces on the needle end, that it provides information on the acting forces during the entire needle movement and that the device is e.g. easy to install on wheeled machines.

The features of the device according to the invention will become more apparent from the appended claims.

In the following, pictures showing the device according to the invention will be explained in more detail.

Figures 1 and 2 show an arrangement when a device according to the method is placed on a cylinder of a rotary machine. Fig. 1 is a schematic radial cross-section of the cylinder from the cylinder wall, and Fig. 2, respectively, is a radially cylindrical wall of the cylinder as seen from the outside of the cylinder. Figure 3 shows a method for impulse transmission from strain gauge strips to recording equipment. In Figures 1 and 2, the purposes of the reference numerals are: 1 generally cylinder wall, 2 needle groove, 3 inter-needle wall, 4 needle, 5 needle head, 6 needle head, 7 strain gauge strips, Θ pulses for impulse transmission, and 9 holes in the cylinder wall. In Figure 3, the purposes of the reference numerals are: 10 strain gauge strips, 11 resistor bridges, 12 differential amplifiers, 13 voltage to frequency conversion, 14 transmitter, 15 receiver, 16 filter, 17 amplifier, 1Θ frequency to voltage conversion, 19 registration.

The following describes the placement of the device on the cylinder of the rotary machine. The strain gauge strips (7), which act as force transducers, are attached to the shaft of the needle (4) by gluing (Fig. 1). At the needle groove (2) corresponding to the needle (4), a hole (9) is made in the cylinder wall (1), the height of which is somewhat greater than the reciprocating movement of the needle (4) and the width, e.g. the width of the needle groove (2) + both adjacent groove walls. (3) width (Figure 2). This provides sufficient clearance for the strain gauge strips (7) and the cables required for impulse transmission (Θ). In the case of a machine with a rotating cylinder, the strain gauge strips (7) rotate with the cylinder. Then the transmission of the pulse from the rotating strips (7) to the fixed recording device takes place by the method according to the diagram shown in Fig. 3.