JP2772369B2 - Weft insertion device for air jet loom - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a weft insertion device for an air jet loom, and more particularly to a weft insertion device capable of performing reliable weft insertion while eliminating yarn breakage. . <Prior Art> As shown in FIG. 3, a conventional weft insertion device of an air-injection loom includes a weft insertion nozzle N from a pressure air source P through a series air path of a pressure regulator R, an air tank T, and an on-off valve V. It is configured to supply pressurized air to the. W is a weft. The pressure regulator R is set to an air pressure suitable for weft insertion. On the other hand, as shown in FIG. 4, the relationship between weft insertion and air injection is such that air is injected from a weft insertion nozzle (hereinafter referred to as advance injection) prior to release of the weft (opening of the weft gripper), and The leading end is extended in front of the nozzle, and then the weft is released to insert the weft, and the air injection before the weft is restrained is stopped. However, if air is injected from the weft insertion nozzle at a pressure suitable for weft insertion before the weft is released, the weak weft may be cut at this time. For this reason, as disclosed in Japanese Patent Application Laid-Open No. 56-340, it has been proposed to weaken the flow of the air ejected from the nozzle outlet during the preceding injection. <Problems to be Solved by the Invention> However, although such means can prevent the breakage of the weft during the preceding injection, the operating speed of the loom and therefore the flight speed of the weft are increased in order to increase productivity. It has been found that when the supply air pressure to the weft insertion nozzle is increased, the weft insertion speed sharply decreases at the end of the weft insertion, thereby causing thread breakage. In other words, because the pulling force of the weft by the air flow is high, when the weft is caught by the weft grasper or stopped by the stopper at the end of the weft insertion and the traveling is stopped, the flight speed of the weft is increased. The sharp drop to zero results in thread breaks. In order to solve this, it is conceivable to terminate the air injection earlier, but this will reduce the overall weft insertion force, making the weft insertion unstable and causing the air flow to end at the end of the weft insertion. Since it hardly acts on the weft, the weft cannot be stretched straight. In other words, since the air flow does not act on the leading end of the weft, the weft is loosened and may be woven as it is to form a woven flaw. The present invention has been made in view of such a fact, and an object of the present invention is to enable suitable weft insertion without causing breakage or loosening of the weft at the end of weft insertion. <Means for Solving the Problems> For this reason, the present invention provides an air path set at a relatively low pressure and an air path set at a higher pressure than this air path for the weft insertion nozzle. In the air path, an air tank is arranged from the pressure air source side, an electromagnetic on-off valve in this order, and further connected to the weft insertion nozzle from the on-off valve via a communication portion of a plurality of air paths, In the air path set at a relatively low pressure, between the on-off valve and the communication portion, in a weft insertion device of an air-jet loom provided with a check valve that allows air to flow only into the communication portion side, While providing the flying state detecting means for detecting the flying state of the weft, the on-off valve on the air path side set to the high pressure is opened in the middle of the air injection period of the weft insertion nozzle to open the weft insertion nozzle. High-pressure air is supplied, and the flying state detecting means is The valve is closed based on the output of the stage to cut off the supply of high-pressure air, and for the remainder of the period, the air path set at the relatively low pressure is selected to supply the relatively low-pressure air to the weft insertion nozzle. A control device is provided. <Operation> In this configuration, at the time of preceding injection, air at a relatively low pressure is supplied from an air path set at a relatively low pressure, and the leading end of the weft is drawn forward of the nozzle to prepare a weft insertion state. Subsequently, at the time of weft insertion, based on the output of the weft flight state detection means, high-pressure air is supplied from an air path set at a high pressure for a period corresponding to the flight state of the weft to provide a high traction force to the weft. In addition, the weft running speed is increased, and then relatively low-pressure air is supplied from an air path set at a relatively low pressure, so that the weft running speed is reduced and the weft is extended. <Examples> Examples of the present invention will be described below. FIG. 1 shows an embodiment. 1 is a weft insertion nozzle, 2 is a weft thread, 4 is a pressure air source, 5 is a first air path, 6 is a second air path, and 7 is a control device. The first air path 5 includes a series circuit in which a pressure air source 4, a pressure regulator 8L, and an air tank 9L are arranged in this order. Second
Air path 6 is from pressure air source 4 to pressure regulator 8H, air tank 9H
In this order. The pressure regulator 8H is set at a higher pressure than the pressure regulator 8L. The control circuit 7 includes an electromagnetic on-off valve 10 connected to the first air path 5, an electromagnetic on-off valve 11 connected to the second air path 6,
It comprises a check valve 12 for preventing air flow from the second air path 6 side to the first air path 5 side. Reference numeral 15 denotes a weft storage device, which winds a predetermined amount of the weft 2 around the drum 16 held in a stationary state by a rotating arm 17. Reference numeral 18 denotes a locking member that moves in and out of the peripheral surface of the drum 16 and is moved by an electromagnetic actuator 19. The weft yarn 2 drawn from the drum 16 is passed through a weft insertion nozzle 1 via a guide 20. Reference numeral 21 denotes a photoelectric type weft sensor as a weft flight state detecting means, which outputs a pulse signal when the weft 2 passes in front of the weft sensor 21 while rotating around the drum 16. A counter 22 counts a pulse signal from the weft sensor 21 and outputs it to the control circuit 23. Reference numeral 25 denotes an angle sensor, which has 360 projections 27 around a rotation shaft 26 that rotates in synchronization with the main shaft of the loom and has a through hole 28 provided at a position corresponding to the main shaft 0 °. A disc 29, a pulse generator 30 that outputs a pulse signal for each of the protrusions 27, a photoelectric sensor 31 that outputs a pulse signal when facing the through-hole 28, and a pulse signal from the sensor 31 for zeroing. After that, the pulse signal from the pulse generator 30 is counted up, and a count 32 for outputting an angle signal of 1 °, 2 °,. The output of the counter 32 is input to the control circuit 23. Reference numeral 33 denotes a switching circuit which turns on and off the current supplied to the on-off valve 11. The switching circuit 33 is turned ON and OFF by the output of the control circuit 23. Note that the counter 22 is cleared by a reset signal output when the control circuit 23 outputs 0 °. Further, the on-off valve 10 is turned on and off by the control circuit 23 at a predetermined timing. The switching circuit 33 is turned on at a predetermined time at the beginning of the weft insertion by the output of the control circuit 23, and opens the on-off valve 11, and the predetermined weft insertion length, in this example, the number of rewinds of the weft from the drum 16 is a predetermined value. Is turned off when it becomes
It is controlled to close 1. In this example, drum 1
It is set so that weft insertion is equivalent to one pick by rewinding four times from 6. Therefore, when the counter 22 counts 3, the switching circuit 33 is turned off. Next, the operation will be described with reference to FIG. First, at a predetermined timing before the start of weft insertion, the on-off valve 10 on the first air path 5 side is opened for pre-injection.
As a result, relatively low-pressure air set by the pressure regulator 8L from the first air path 5 reaches the weft insertion nozzle 1 via the check valve 12 and is ejected from the ejection outlet thereof (FIG. 2A). 2 is extended forward of the nozzle 1. Immediately after this, at a predetermined time, the locking body 18 is pulled out of the drum 16 by the electromagnetic actuator 19, the switching circuit 33 is turned on, and the on-off valve 11 is opened. As a result, the weft yarn 2 is drawn out while rotating around the peripheral surface of the drum 16 and inserted into the weft, and the weft insertion is performed by high-pressure air from the second air path 6. That is, by opening the on-off valve 11 on the second air path 6 side, high-pressure air set by the pressure regulator 8H is supplied from the second air path 6 to the weft insertion nozzle 1 side, and the check valve 12 is closed. At the same time, the gas is ejected from the ejection port of the nozzle 1 (FIG. 2B),
The weft yarn 2 is injected into the warp shedding while being pulled with a high pulling force. The injected weft yarn 2 is conveyed by the jet airflow or the auxiliary jet airflow. Due to this high traction, the weft 2 will fly at high speed. At this time, although the air pressure gradually decreases as shown in FIG. 2B, it is considered that the air in the air tank 9H is consumed while the supply from the pressure regulator 8H is delayed. Since the weft sensor 21 outputs a pulse signal every time the weft 2 passes in front of the weft sensor 21 in this turning process, the counter 22 counts as 1, 2,. Counter 22
Counts 3, the control rotation 23 becomes the switching circuit
As a result of turning off the switch 33 and closing the on-off valve 11 to stop the supply of high-pressure air from the second air path 6, weft insertion is continued by the low-pressure air in the first air path 5. That is, since the on-off valve 11 is closed, the first air path 5
When the air pressure on the side becomes higher, the check valve 12 is opened, and low-pressure air is supplied to the nozzle 1 (FIG. 2C), and the air is weakly jetted from the jet port. Although the weft 2 is conveyed while being pulled by the relatively weak airflow, the flying speed of the weft 2 gradually decreases. Since the weft yarn 2 is weak but is exposed to the airflow in the warp shed, the leading end of the weft yarn 2 is also stretched straight by receiving the stretching force. Next, at a predetermined timing, the on-off valve 10 closes and the air injection is stopped. Thereafter, the electromagnetic actuator 19 is operated so that the locking member 18 protrudes into the surface of the drum 16 between the third and fourth windings, the weft 2 is locked by the locking member 18, and the weft insertion is completed. After this, the running speed of the weft 2 is reduced as described above, so that the speed of the weft 2 is not sharply reduced.
Can be prevented from being cut. The counter 22 is zeroed by a pulse signal transmitted at 0 °. If the supply time of the high-pressure air in the second air path 6 is controlled in accordance with the weft insertion state in this way, more suitable weft insertion can be performed. In this case, the supply stop of the second air path 6 may be controlled by reaching the weft end to a predetermined position. The air tanks 9L and 9H are not necessarily required, but are preferably installed to supply air at a stable pressure. <Effects of the Invention> As described above, according to the present invention, at the time of preceding injection, the front end of the weft yarn is extended toward the front of the nozzle while supplying low-pressure air to the weft insertion nozzle to eliminate yarn breakage. At the time of weft insertion, based on the output of the weft flight state detection means, for a period corresponding to the flight state of the weft, supply high-pressure air to give a large traction force to the weft and rapidly increase the flight speed of the weft. Perform high-speed flight, and then supply low-pressure air to reduce the traction force and reduce the flight speed of the weft, but also to stretch the weft by pulling the tip of the weft, so weft breaks can be resolved In addition, loosening of the weft can be eliminated. Also, the present invention does not directly connect the relatively low-pressure air path and the high-pressure air path, and at least the relatively low-pressure air path is provided between the on-off valve and the communication section, toward the communication section side. Since the check valve that allows air to flow only is interposed, weft insertion can be reliably performed without accurately setting the timing at which the high-pressure side and low-pressure side on-off valves interlock. In other words, the open / close valve on the relatively low-pressure air path side can be set to the open state regardless of the open / close valve on the high-pressure air path side. When the supply air is switched from high pressure to low pressure, the low pressure air is supplied to the weft insertion nozzle via the check valve as soon as the open / close valve on the high pressure air path side is closed. Become. Further, according to the present invention, the supply period of the high-pressure air is cut off based on the output of the weft flying state detecting means, and the injection period of the high-pressure air is changed according to the flying state of the weft. By increasing the high-pressure air injection period in response to slow running, the weft transfer force can be increased to prevent poor weft insertion. The power can be reduced so that weft insertion does not end prematurely. Therefore, even if the yarn (yarn type) to be inserted changes, the appropriate weft conveyance force can always be obtained automatically, and thus, the inferior weft insertion can be suppressed and the cloth quality can be improved. The effect is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an embodiment of the present invention, FIG. 2 is a control characteristic diagram of the embodiment, FIG. 3 is a schematic diagram showing a conventional example,
FIG. 4 is a control characteristic diagram in a conventional example. 1 ... weft insertion nozzle, 2 ... weft, 4 ... pressure air source 5 ... first air path, 6 ... second air path, 7 ... controller 8L, 8H ... pressure regulator, 9L, 9H …… Air tank, 10,11… Open / close valve 12… Check valve, 15… Weft storage device, 16… Drum 18… Locking body, 21… Weft sensor, 22… Counter 23… Control circuit, 25… Angle sensor, 33… Switching circuit

   ────────────────────────────────────────────────── ─── Continuation of front page       (56) References JP-A-56-343 (JP, A)                 JP-A-65-152851 (JP, A)                 JP-A-60-17148 (JP, A)                 Showa 60-82476 (JP, U)

Claims (1)

(57) [Claims] An air path (5) set at a relatively low pressure and an air path (6) set at a higher pressure than the air path (5) are provided for the weft insertion nozzle (1). , 6) are connected to the air tank (9L,
9H), an electromagnetic on-off valve (10, 11), and the weft insertion nozzle (10, 11) through the communicating portion of a plurality of air paths (5, 6). 1), and a check valve that allows air to flow only into the communication section between the on-off valve (10) and the communication section in the air path (5) set at a relatively low pressure. In a weft insertion device of an air jet loom equipped with (12), a flying state detecting means (2) for detecting a flying state of the weft (2).
In the meantime, the on-off valve (11) on the side of the high-pressure air path (6) is opened in the middle of the air injection period of the weft insertion nozzle (1) to open the weft insertion nozzle (1). High-pressure air is supplied to the valve, and the valve is closed based on the output of the traveling state detecting means (21) to interrupt the supply of high-pressure air, and the rest of the period is set to the relatively low pressure. A weft insertion device for an air-jet loom, characterized in that a control device (7) for selecting the air path (5) and feeding relatively low-pressure air to the weft insertion nozzle (1) is provided.