JPH0480128B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a needle for an automatic pull-out device for defective weft yarns in a loom, and more specifically to a needle for a device for automatically pulling out defective weft yarns in a loom. This invention relates to the structure of a needle used in a device that automatically pulls out defective weft yarns from a shed when a loom stops operating due to a feeding defect or a filler error.

(Prior art) The technology to automatically take out the defective weft from the shed when the loom stops operating due to defective weft insertion is as follows.
For example, there is an invention disclosed in Japanese Patent Application Laid-Open No. 58-220856.

The device of the present invention has a defective weft release member and a capture member, and the defective weft yarn after pick-up is caught by the release member and separated from the fabric, and is held between the warp rows by the capture member. It is pulled out through the shaft and out of the shed.

However, in the case of this device, there is a lack of certainty in the release of defective weft yarns from the loom by the release member, and there is also a lack of certainty in the transfer of defective weft yarns from the release member to the capture member, resulting in overall operational errors. Easy to do. Furthermore, if an attempt is made to avoid operational errors, the release member will forcefully scratch the cloth surface, which will easily cause scratches.

In order to avoid such inconvenience, the present inventor separately proposed a technique for automatically pulling out defective weft yarns using a needle. The needle used in this technology has a hook-shaped weft gripping part that opens upwards, and is driven by a cam that rotates in synchronization with the operation of the loom to hold the weft in the vertical plane in the warp direction near the fabric front near the fabric edge on the weft injection side. It is something that oscillates within itself.
In the case of a normal weft, the tip of the needle is driven into the shed by a cam drive before weft insertion is detected on the warp arrival side, and the tip is removed from the shed after weft insertion is detected on the weft arrival side. In the case of a defective weft, the tip of the needle is driven into the shed by a cam drive before weft insertion is detected on the weft arrival side, and the needle is separated from the cam drive by the action of a solenoid that is energized in response to the occurrence of a defective weft insertion. The machine prevents the tip of the needle from escaping from the shed, and after the loom has stopped and the defective weft has exited, the servo motor, which rotates 360 degrees in response to the occurrence of defective weft insertion, allows the needle to penetrate deeper into the shed. By positioning the weft gripping section under the defective weft yarn and completely letting the rear needle escape from the shed, the weft gripping section captures the defective weft yarn and pulls out a part of it outside the warp row. This returns the rear hand to the control of the cam drive.

In the above operations, the needle is first required to easily catch the defective weft yarn in its weft gripping section. Moreover, once the defective weft yarn has been captured, it is required to firmly hold it and not allow it to fall off.

Furthermore, since the needles pass between the warp rows and move in and out of the shed during each weft insertion cycle, it is preferable that the needles be as thin as possible. However, on the other hand, since the needle is strongly struck against the textile fabric during weft striking between the textile fabric and the defective weft, it is required to be strong enough to withstand the impact.

Furthermore, when a weft insertion failure occurs, the needle's top-opening hook-shaped weft gripping section moves in and out of the shed between the warp rows, so the weft gripping section does not catch adjacent warp threads (especially when entering from the shed). ) is required when escaping.

(Objective of the Invention) An object of the present invention is to provide a needle that can automatically pull out defective weft yarns using a needle, and which can capture defective weft yarns without any operational errors and pull them out of a shed without falling off.

Another object of the present invention is to provide a needle that is sufficiently thin and can withstand the impact of weft beating when the needle is used to automatically pull out defective weft yarns.

Still another object of the present invention is to provide a needle that can enter and exit a shed without disturbing the warp row in automatic withdrawal of defective weft yarns using a needle.

(Basic Structure of the Invention) In the needle of the present invention, at least the weft gripping portion is formed of a shape memory alloy, and has a first memory shape suitable for capturing defective wefts and preventing the captured defective wefts from falling off. It has a second memory shape.

(Embodiment) FIG. 1 shows an example of the needle of the present invention, in which a needle 8 is fixed to the tip of a swinging lever 7 and extends forward and downward, and has a tip 81 and an upper side thereof. It has an open hook-shaped weft gripping part 82, and is made of a shape memory alloy that undergoes two-way martensitic transformation as a whole. The inside of the needle 8 is hollow up to the vicinity of the gripping part 82, and the heating nichrome wire 83 inserted therein is connected to an appropriate power source (not shown) by a conducting wire 84. It is turned on. In this example, a cooling nozzle 5 is provided in front of the needle 8, and is turned on when a defective weft is caught by the needle 8 to direct cooling water or air toward at least the gripping portion 82 of the needle 8. and inject it.

An example of shape change due to martensitic transformation in this invention is shown in FIGS. 2A and 2B. In this case, the entire needle 8 is made of a shape memory alloy.

In the state shown in FIG. 2A, the needle 8 has the first memorized shape, and at that time, the opening degree D of the weft gripping section 82
is larger than the weft diameter. Therefore, when catching a defective weft yarn, the defective weft yarn is likely to enter the gripping portion 82.
Nichrome wire 8 at the timing when the defective weft is captured
3 is turned on, the needle 8 assumes the second memory shape shown in FIG. becomes. Therefore, the defective weft caught by the weft gripping section 82 is tightly held, so that it will not fall off when it is pulled out from the shed through the warp rows. When the defective weft yarn that has been pulled out is removed from the needle 8, the cooling nozzle 5 is turned on to cool it down, and the needle 8 returns to the first memorized shape shown in FIG. 2A.

However, in the case of ordinary shape memory alloys, martensitic transformation occurs at a low temperature of about 30 to 50°C, and weft insertion defects do not occur very often. Therefore, in practice, it is not necessary to actively cool the
→There is sufficient time to lower the temperature necessary for the change in memory shape.

In the above example, the first memory shape shown in FIG. 2A is given to the needle 8 under normal conditions, and the second memory shape shown in FIG. 2B is given to the needle 8 by heating only when a defective weft is caught. However, you can also do the opposite. That is, normally, the needle 8 is given the first memory shape shown in FIG. 2A by heating, and only when a defective weft is caught, the heating is stopped and cooling is performed to give the needle 8 the second memory shape shown in FIG. 2B. You may also give it a shape. However, this second method is disadvantageous compared to the first method because power consumption for heating increases and active cooling is required.

Furthermore, as a third method, in normal times, set the hand 8 to Figure 2 B.
In response to the occurrence of defective weft insertion, the needle 8 is heated to capture the defective weft yarn that gives the first memorized shape shown in FIG. The captured defective weft may be prevented from falling off by returning to the second memorized shape shown in FIG. This method consumes less power than the second method, but depending on how the defective weft is removed from the needles 8 following withdrawal, it may be heated again at the time of removal and the first method shown in FIG. This is still disadvantageous compared to the first method, as it may be necessary to return to the memorized shape, and in addition, active cooling is required.

Other examples of shape changes are shown in FIGS. 3A and 3B. In this case as well, the entire needle 8 is made of a shape memory alloy. In the state shown in FIG. 3A, the needle 8 has a first memorized shape, which may be the same as that shown in FIG. 2A. That is, since the opening degree D of the weft thread gripping section 82 is larger than the diameter of the weft thread, the faulty weft thread easily enters the gripping section 82 when capturing the faulty weft thread. When the nichrome wire 83 is turned on at the timing when the defective weft is captured, the needle assumes the second memorized shape shown in FIG. 3B due to martensitic transformation as the temperature rises. At this time, the opening degree D' of the weft yarn gripping portion 82 is smaller than the diameter of the weft yarn, as in the case of FIG. 2B. Therefore, the defective weft caught and entered by the weft gripping section 82 is firmly held, so that it will not fall off when it is pulled out from the shed after passing between the warp rows. In addition, in this example, the second memory shape is approximately linear. Therefore, during this shape change, there is an effect of pulling the defective weft yarn caught in the front of the weaving back from the front of the cloth, making it easier to pull out the defective weft thread between the warp rows than in the case of the shape shown in Fig. 2B. Become. Once the defective weft yarn that has been pulled out is removed from the needle 8, the needle 8 returns to the first memorized shape shown in FIG. 3A by active cooling or natural cooling.

Still other examples of shape changes are shown in FIGS. 4A and 4B.
In this case, at least the vicinity of the tip 81 of the needle is formed of a shape memory alloy. In the state shown in FIG. 4A, the needle 8 has the first memorized shape and does not have a weft gripping portion. If weft insertion failure occurs, use needle 8.
When the needle 8 is heated at a timing when the tip 81 of the needle 8 reaches a certain level below the defective weft, the needle 8 assumes the second memorized shape shown in FIG. 4B due to martensitic transformation as the temperature rises. At this time, the tip is bent into an upwardly opening hook shape and becomes a weft gripping portion 85 whose opening degree D' is smaller than the diameter of the weft, firmly gripping the defective weft.
This example is relatively easy to manufacture. Furthermore, since the first memorized shape in the normal state does not have a weft gripping portion, there is less risk of the warp being caught.
Furthermore, even when capturing defective weft yarns, the degree of penetration of the needle into the shed is small, and what is more, it is the thin tip 81 that penetrates.
Since only the needles need to be removed, disturbance of the fabric structure due to needle penetration can be kept to a minimum.

In the example shown in FIG. 5, only the weft gripping portion 86 is made of a shape memory alloy. In the illustrated state, the needle 8 has the first memorized shape, and the opening degree D of the weft thread gripping portion 86 is larger than the diameter of the weft thread. If the gripping portion 86 is heated when capturing a defective weft yarn, martensitic transformation occurs as the temperature rises, and the gripping portion 86 moves toward the main body 87 side, and its opening becomes smaller than the weft diameter.

By the way, when the needle catches and grips the defective weft yarn and pulls it away from the weaving front, the weft can be smoothly pulled out from the shed. For this purpose, as shown in FIG. 6A, the weft gripping section 82
It is preferable that the warp direction dimension T of the main body 87 is as large as possible at the position. Further, in order to facilitate the shape change, it is preferable that the warp direction dimension T' of the weft thread gripping portion 82 is as small as possible. Generally, it is desirable to have the relationship T>T'.

Furthermore, the needle 8 which has captured and gripped the defective weft passes between the warp rows and escapes from the shed, but at this time there is a risk that the upwardly opening hook-shaped weft gripping section 82 may catch the adjacent warp. To avoid this, the weft gripping section 82
The weft direction dimension W of the main body 87 at the position is the sixth
As shown in Figure B, the weft direction dimension of the weft gripping part 82
It is desirable to take it larger than W′.

In the case of further active cooling, the cooling nozzle 5 is used in the example shown in FIG. 1, but a cooling member may also be provided within the needle 8. That is, as shown in FIG. 7, a cooling thermoelectric element 88 is provided inside the needle 8 in parallel with the heating nichrome wire 83, and the Peltier effect is utilized to absorb heat by electrical energy.

In the above example, the case where the heating and cooling elements were built into the needle was mainly explained, but both of them may be of an external type. An example is shown in FIG. That is, a heating/cooling unit 90 is provided which opens facing the weft gripping portion 82 of the needle 8, a motor 91 and a fan 92 are installed inside this unit, and a heating heater 93 and a cooling thermoelectric element 94 are provided in front of the heating/cooling unit 90. Hot air or cold air is selectively blown onto the needle 8.

(Effects of the Invention) According to the present invention, when catching a defective weft, the needle has a shape suitable for capturing and separating it from the weft front, and when pulling out a defective weft, the needle has a shape that prevents the weft from falling off. Therefore, the work of pulling out defective weft yarns can be carried out reliably.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view showing an example of the needle of this invention, FIGS. 2A to 4B are side views showing several examples of changes in the shape of the needle of this invention, and FIG. 5 is a side view of the needle of this invention. A partially sectional side view showing another example; FIGS. 6A and 6B are side and front views showing the dimensional relationship of each part of the needle of the invention; FIG. 7 is a side view showing still another example of the needle of the invention. FIG. 8 is a partially sectional side view showing still another example of the needle of the present invention. 8... Needle, 82, 85, 86... Weft gripping part,
83...Nichrome wire for heating, 88...Thermoelectric element for cooling.

Claims (1)

[Claims] 1. At least the weft gripping portion is formed of a shape memory alloy that takes a first memory shape suitable for capturing defective wefts and a second memory shape that prevents the captured defective wefts from falling off. A needle for an automatic pull-out device for defective weft yarns in a loom, characterized in that: 2. The needle according to claim 1, wherein the weft gripping section made of a shape memory alloy has a built-in heating member. 3. Has a hook-like weft gripping part that opens upward in the middle in the longitudinal direction, and the degree of opening thereof is larger than the diameter of the weft in the first memory shape and larger than the diameter of the weft in the second memory shape. Needle according to claim 1, characterized in that it is smaller. 4. According to claim 1, which has a second memorized shape and has a hook-shaped weft gripping portion that opens upward at its tip, and the degree of opening of the weft gripping portion is smaller than the diameter of the weft. needle.