JPH0314663A - Sensor for needle breakage in knitting machine - Google Patents

Abstract

PURPOSE:To obtain the subject sensor capable of sensing needle breakage with a high accuracy without any erroneous sensing due to oil fouling, etc., and producing a high quality knitted fabric without knitting defects by mounting magnetic resistance elements close to knitting needles so as to enable sensing of a change in magnetic field relatively to the knitting needles of a knitting machine. CONSTITUTION:In a knitting machine 1 composed of a knitting mechanism 2 for knitting a tubular fabric 3 with vertical motion of knitting needles 21 provided in a needle cylinder 20 rotatable around a vertical shaft and reciprocation of the needle cylinder 20 of a sinker 22 in the radial direction and a cylindrical unit 4 for sucking and recovering the tubular fabric 3 knitted to a prescribed size with the knitting mechanism 2, magnetic units 8 and magnetic resistance elements 9 are arranged near movement passages of the knitting needles 21 in a state in which the knitting needles 21 are present in the magnetic sensitive direction of the magnetic resistance elements 9. A signal indicating a change in resistance value obtained from the magnetic resistance elements 9 with time is led to a circuit for converting the signal into a signal corresponding to the interval of the normal knitting needles 21 and needle breakage is sensed from the irregularity in interval of the normal knitting needles obtained from an output of the aforementioned circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a needle breakage detection device in a knitting machine for socks and the like.

When the hook portion of a knitting needle in a strained knitting machine deteriorates or has poor strength, or when an abnormal tensile strength is added to the hook portion, the hook portion is missing and the needle breaks. When such needle breakage occurs, the yarn cannot be hooked properly, resulting in knitting flaws and a significant decrease in commercial value.

Conventional devices for detecting needle breakage include the bellows stop motion, which detects contact by centrifugal force when the bellows of a knitting needle is released from the constraints of the yarn, and a device that uses an optical fiber sensor near the knitting needle to detect changes in the amount of light. There is.

However, in the case of using the above-mentioned bellow stop motion, there is a problem that the bellows does not necessarily face directly to the side due to centrifugal force, resulting in a significantly low detection accuracy.

On the other hand, in the case of the latter optical fiber sensor, this problem is solved, but since it is an optical type, there is a problem that malfunctions may occur due to oil stains and the like.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a needle break detection device that has high detection accuracy and is resistant to oil stains.

In order to achieve the above object, the present invention is characterized in that a magnetic resistance element is attached close to the knitting needles of a knitting machine so that changes in the magnetic field can be detected with respect to the knitting needles.

More specifically, the present invention arranges a magnet body and a magnetoresistive element near the movement path of the knitting needle in a state where the knitting needle exists in the direction of magnetic sensitivity of the magnetoresistive element, and the resistance value obtained from the magnetoresistive element is determined over time. This method is characterized in that a signal indicating a change in the knitting needle is guided to a circuit that converts it into a signal corresponding to the normal knitting needle spacing, and needle breakage is detected from the unevenness of the normal knitting needle spacing obtained from the output of this circuit.

More specifically, the present invention comprises a magnet body disposed near the movement path of a knitting needle, and a magnetoresistive element disposed in a state where the knitting needle exists in a magnetic path of lines of magnetic force generated by the magnet body and in a direction of magnetic sensitivity. and a pulsing processing means for pulsing the temporal change in resistance value obtained from the magnetoresistive element as the knitting needle moves;
It is characterized by comprising a pulse interval measuring means for measuring the time interval of each pulse obtained from the pulse processing means, and a determining means for determining needle breakage from the time interval of each pulse obtained from the pulse interval measuring means. It is said that

The Tachi-Ichi-Ichiri knitting needle is made of metal, and its relative magnetic permeability (μS) is higher than l. For this reason, if the knitting needles moving near the magnetoresistive element are normal and have no needle breakage, many lines of magnetic force will concentrate on the knitting needles, resulting in a large change in the resistance value detected by the magnetoresistive element. In the case of knitting needles with bends, the number (density) of magnetic lines of force decreases, and the change in resistance value decreases.

Therefore, needle breakage can be detected from the magnitude of the change in resistance value.

Fig. 1 shows an example of the present invention applied to a circular sock knitting machine.

A circular knitting machine 1 supplies comparatively light-colored yarn from a plurality of raw yarn cones (not shown) above the machine to a knitting mechanism 2, and a cylindrical fabric knitted into a predetermined size by the satin mechanism 2. The basic structure is to suck and collect 3 into a cylinder 4.

Note that, prior to the above-mentioned main knitting from one raw yarn cone, makeup yarn is supplied to the round pigeon machine 1 and initial knitting is performed.

The W* mechanism 2 has a needle cylinder 20 that is freely rotatable around a vertical axis as its main structural member, and controls the vertical movement of the knitting needles (21 dollars) 21 provided on the needle cylinder 20 and the sinker 2.
The structure is such that the cylindrical fabric 3 is erected by the cooperative action of the reciprocating movements (sliding movements) of the needle cylinders 20 in the radial direction. The knitting needles 21... are installed in the grooves of the needle cylinder 20, and the vertical movement of the knitting needles 21... is controlled by a latch and a latch guard cam (none of which are shown) provided thereon.
It is done through. On the other hand, the sinkers 22 are held by a top cylinder 23 screwed to the inner surface of the upper end of the needle cylinder 20 so as to be able to reciprocate in the above direction. Shinka 2
The rear end portions of 2... are covered with sinker caps 24.

The rotation of the needle cylinder 20 is performed via a gear mechanism consisting of a sleeve gear 26 connected to the needle cylinder via a key 25 and a bevel gear 27 meshing with the sleeve gear. Bevelga 2
7 is driven by a drive mechanism (not shown). In addition,
The needle cylinder 20 rotates in the R direction (see Figure 2), and in synchronization with this rotation, a circular cuff (not shown) provided inside the needle cylinder 20 rotates in the same direction. .Circular cassette is for cutting yarn feed.

A ring-shaped auxiliary table 5 is provided concentrically outside the sinker camp 24, and a magnet body 8 and a magnetic resistance element 9 are provided on this table via a mounting plate 6 and a position adjustment member 7. There is. These mounting plates, position adjustment members,
As shown in FIG. 1, the magnet body and the magnetoresistive element are arranged in pairs on the left and right at an angle of about 180° about the center of rotation of the knitting needle. The reason for arranging the needles in pairs on the left and right is to detect needle breakage when knitting a part of the garter of a sock in order to improve detection accuracy.

In other words, when knitting a part of the garter, every other knitting needle 21 moves downward, so the pitch of the knitting needles 21 that protrudes upward as shown in Figure 1 is lower than that when knitting other parts. This increases the resolution of broken knitting needles in relation to the rotational speed of the knitting needles. However, in this case, if the magnetic resistance element and magnet body are only provided on either the left or right side, the needle breakage of the knitting needle moving downward cannot be detected, but the knitting needle moving downward will protrude upward. death,
If instead, another magnetic resistance element and a magnet are provided at a position corresponding to the latter half cycle of the downward movement of the upper knitting needles, it is possible to detect all the needle breaks of all the knitting needles from the output of these two magnetic resistance elements. Can be detected.

In consideration of this, in the embodiment, a pair of left and right magnet bodies and magnetoresistive elements are provided.

The mounting plate 6 is L-shaped as shown in FIG.
The L-shaped bottom side plate piece 6l is attached to the auxiliary table 5. A position adjustment member 7 is attached to the plate piece 62 on the upright side. The position adjustment member 7 includes a fixed member 71 and a slide shaft 72.
．． It is separated from a slide member 73 which can be slid in the axial direction via a slide member 72 . For reasons of mounting space, the position adjusting member 7 is attached to the mounting plate 6 so that the slide member 73 can move in a direction inclined by θ6 (0≦θ<90″) with respect to the horizontal direction.

The tip end surface of the slide member 73 is a socket portion, and the lead terminal 9a of the magnetic resistance element is inserted into the socket portion.
・ is inserted. The magnet body 8 is attached with its S pole side in contact with one surface of the magnetoresistive element 9. The magnetoresistive element 9 and the magnet body 8 are placed as close as possible to the rotational movement path of the knitting needle 21, and are arranged in appropriate magnetic relationship positions such that the hook of the knitting needle is located in the direction of magnetic sensitivity of the magnetoresistive element 9. ing. In Figure 2, 10 is the connection cable, 1
1 is a position adjustment screw.

As shown in FIG. 3, the input signal from the magnetoresistive element 9 is passed through an amplifier 31, a filter 32, a pulsing circuit 33, a gutter detection circuit 34, and so on. The signal is input from the break judgment circuit 35 and the needle break signal output circuit 36 to a certain signal processing circuit, and a needle break is detected.

Next, the operation of the above-mentioned Kaikai will be explained. First, as shown in FIG. 4(a), if a normal knitting needle 21a with no needle breakage comes rotating near the magnetoresistive element 9, the normal knitting needle 21a
Since the metal content is large enough to prevent the needle from breaking, the number of magnetic lines of force concentrated there increases. The magnetoresistive element 9 is shown in FIG. 4(b).
Since the direction of arrow a is the direction of magnetic sensitivity,
The resistance value changes greatly in response to the magnetic force line portion P1 that starts from the normal knitting needle 21a and ends at the S pole of the magnet body 8.

On the other hand, as shown in FIG. 5(a), when knitting needle 2lb with a needle break rotates near the magnetoresistive element 9, the concentration of magnetic lines of force is reduced because the amount of metal is small by the amount of needle break. ease. For this reason, as shown in FIG. 5(b), the knitting needle 2l
Since the number of magnetic lines of force in the magnetic line of force portion P2 starting from b and ending at the S pole is also small, the change in resistance value of the magnetoresistive element 9 with that direction as the magnetically sensitive direction is also small.

During actual detection, the knitting needle 21 approaches the magnetoresistive element 9 and then moves away from it, and then a new knitting needle approaches the magnetoresistive element 9, and so on. The value changes periodically, and if there is a knitting needle with a needle break, there is no difference in the resistance value of the magnetoresistive element than when the needle is far away from the magnetoresistive element, so the period of change in resistance value changes. become longer.

FIG. 6(a) shows changes in the detection signal of the magnetoresistive element 9 in a knitting machine in which one knitting needle is broken.

This detection signal is amplified by an amplifier 31, and a filter 32
After being waveform-shaped, the signal is input to a pulse forming circuit 33 and a gutter part detection circuit 34. The pulsing circuit 33 performs pulsing processing in which one trigger pulse is generated based on the peak value of the detection signal. FIG. 6(b) shows a pulse signal obtained by such pulse processing. The garter part detection circuit 34 monitors the length of the period of the detection signal (a) and determines whether the part currently being knitted is part of the garter of the sock. If it is determined that it is part of the gutter, the needle breakage determination circuit 35 is switched to an enabled state. Although the needle breakage judgment circuit 35 is not shown, it includes a clock generator that generates a high-speed clock, a counter that counts the high-speed clock between one trigger pulse and the next trigger pulse output from the pulse generator 33, and a counter. A comparator is used to compare the count value with a reference value corresponding to normal knitting needle spacing.

If adjacent knitting needles protruding upwards are normal, the count value on the counter will be equal to the reference value, but if one needle breaks, the distance between normal knitting needles will double.
When the count value of the counter no longer matches the reference value, an output is generated from the comparator.

The needle breakage signal output circuit 36 amplifies the output from this comparator and outputs it as a needle breakage signal to the control section of the knitting machine. Upon receiving this output, the control section issues a warning or stops the knitting machine. Do the following.

In the embodiment, needle breakage is detected only while knitting a part of the sock garter, but it is of course possible to perform the detection operation while knitting other parts. It is. In that case, only one magnet and one magnetoresistive element are required. As explained above, according to the needle breakage detection device according to the present invention, since the needle breakage of a knitting needle is detected in a non-contact state using a magnetic resistance element, it is possible to reliably detect a needle breakage and also to detect a needle breakage. Since it uses a physical phenomenon called magnetoresistive effect as its principle, it has the advantage of being able to detect needle breakage with high precision without causing false detections due to oil stains as with conventional optical detection means.

There is fruit.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a knitting machine showing one embodiment of the present invention;
The figure is a perspective view showing the structure of the main part of the present invention, FIG. 3 is a diagram showing a processing circuit for detecting needle breakage, and FIGS. 4 and 5 are magnetic resistances when the needle is broken and when the needle is normal. FIG. 6, which explains the difference in detection states of the elements, is a waveform diagram illustrating the needle breakage detection operation. 6 Figure 2

Claims (2)

[Claims] (1) A needle break detection device for a knitting machine, characterized in that a magnetic resistance element is attached close to the knitting needles of the knitting machine so as to be able to detect changes in the magnetic field of the knitting needles. (2) A magnet body and a magnetoresistive element are arranged near the movement path of the knitting needle in a state where the knitting needle exists in the direction of magnetic sensitivity of the magnetoresistive element, and the temporal change in the resistance value obtained from the magnetoresistive element is shown. A needle break detection device for a knitting machine, characterized in that the signal is guided to a circuit that converts the signal into a signal corresponding to the normal knitting needle spacing, and needle breakage is detected from the unevenness of the normal knitting needle spacing obtained from the output of this circuit. . (3) a magnet arranged near the movement path of the knitting needle; a magnetoresistive element arranged so that the knitting needle exists in the magnetic path of the lines of magnetic force generated by the magnet, and in the direction of magnetic sensitivity; and the knitting needle. pulsing processing means for pulsing the temporal change in resistance value obtained from the magnetoresistive element as the magnetoresistive element moves; pulse interval measuring means for measuring the time interval of each pulse obtained from the pulsing processing means; and the pulse interval. A needle breakage detection device for a knitting machine, comprising: determination means for determining needle breakage from the time interval of each pulse obtained from the measurement means.