阅读说明：本技术 织机的纬纱切断装置 (Weft cutting device for loom ) 是由 平野大慈 田村公一 于 2020-01-31 设计创作，主要内容包括：本发明公开了一种织机的纬纱切断装置,其通过供给及排出空气使柱塞往复移动而使可动刀往复摆动,其中,所述纬纱切断装置具备在所述汽缸内沿所述汽缸的长度方向延伸设置的引导部,所述柱塞设置为,在收容于所述汽缸内的状态下,在引导孔中由所述引导部滑动引导,所述引导孔与所述长度方向平行地形成。根据本发明,可提供一种不易产生汽缸的磨损的结构,该汽缸的磨损是导致纬纱切断装置的高维护成本的原因。(The invention discloses a weft cutting device of a loom, which enables a plunger to reciprocate through supplying and discharging air so as to enable a movable knife to reciprocate and swing, wherein the weft cutting device is provided with a guide part which is arranged in a cylinder and extends along the length direction of the cylinder, the plunger is arranged in a guide hole and is guided by the guide part in a sliding way under the state of being accommodated in the cylinder, and the guide hole is formed in parallel with the length direction. According to the present invention, it is possible to provide a structure in which wear of the cylinder, which is a cause of high maintenance cost of the weft cutting device, is less likely to occur.)

1. A weft cutting device for a loom, comprising: a fixed knife fixed on the knife seat; a movable blade pivotally supported by the holder; a shift lever pivotally supported by the tool rest so as to be swingable, and connected to the movable blade so as to swing the movable blade by swinging; a plunger which is housed in a cylinder provided in the tool holder so as to be capable of reciprocating, engages with the shift lever, and swings the shift lever by the reciprocating movement; an air supply device for supplying air into the cylinder to reciprocate the plunger, the weft cutting device for a loom being characterized in that,

a guide part extending along the length direction of the cylinder in the cylinder,

the plunger is provided to be slidably guided by the guide portion in a guide hole formed in parallel with the longitudinal direction in a state of being accommodated in the cylinder.

2. Weft cutting device for weaving looms according to claim 1,

the guide hole is a bottomed hole having a bottom surface and being open to a pressure receiving surface that is an end surface on one end side of the plunger,

the guide portion is provided to extend from an inner end surface of the cylinder opposed to the pressure receiving surface of the plunger toward an inside of the cylinder,

the weft cutting device is configured such that the movable blade is positioned at a swing limit on one side of a desired swing range in a state where the bottom surface of the guide hole of the plunger is in contact with an end surface of the guide portion and/or in a state where the inner end surface of the cylinder is in contact with the pressure receiving surface of the plunger, and the movable blade is positioned at a swing limit on one side of a desired swing range

The weft yarn cutting device has a communication passage formed to communicate a space formed between the bottom surface of the guide hole and the end surface of the guide portion along with the reciprocating movement with an outside of the plunger,

the communication passage is formed such that the space is in a negative pressure state in accordance with a relationship between a volume change of the space accompanying the reciprocating movement and an amount of air flowing into the space due to the volume change.

Technical Field

The present invention relates to a weft cutting device for a loom, comprising: a fixed knife fixed on the knife seat; a movable blade pivotally supported by the holder; a shift lever pivotally supported by the tool rest so as to be swingable, and connected to the movable blade so as to swing the movable blade by swinging; a plunger which is housed in a cylinder provided in the tool holder so as to be capable of reciprocating, engages with the shift lever, and swings the shift lever by the reciprocating movement; and an air supply device for supplying air into the cylinder to reciprocate the plunger.

Background

As the weft cutting device described above, for example, a device disclosed in patent document 1 is known. The device disclosed in patent document 1 is a weft cutting device that is attached to a tucking head (tucking block) and cuts an end of a weft after beating-up.

This weft cutting device is mainly composed of a blade holder (scissors holder), and includes a fixed blade (scissors stationary blade) fixed to the blade holder and a movable blade (scissors movable blade) pivotally supported by the blade holder so as to be swingable. In this weft cutting device, the holder has a hole functioning as a cylinder, and the plunger is housed in the cylinder so as to be movable back and forth. The holder is formed with a flow path for communicating the outside with the space in the cylinder. In addition, the weft cutting device is configured to reciprocate the plunger in the cylinder by supplying air into the cylinder and discharging air from the cylinder through the flow path.

Further, an opening portion that opens outward and communicates with the internal space is formed in the cylinder of the holder. Thus, the weft cutting device is configured such that a part of the plunger housed in the cylinder is exposed to the outside.

In this weft cutting device, the plunger is composed of two plunger members (the 1 st plunger and the 2 nd plunger). Further, this weft cutting device includes a shift lever (fork) pivotally supported on the tool holder so as to be swingable, and connected to the movable blade so as to swing the movable blade by its own swing. The displacement rod is provided so that a part thereof passes through the opening and is positioned in the cylinder. The displacement rod is engaged with the plunger so that a portion thereof located in the cylinder is sandwiched between the two plunger members. In the weft cutting device configured as described above, as the plunger reciprocates in the cylinder, the shift lever engaged with the plunger swings, and the movable blade swings and performs a cutting operation.

Disclosure of Invention

Problems to be solved by the invention

However, in a loom, generally, one cutting operation is performed on a weft inserted every weaving cycle (every rotation of a loom main shaft). In addition, in the loom, the loom main shaft is driven to rotate at a speed of several hundreds of revolutions per minute to perform weaving. Therefore, in the case of using a device such as that disclosed in patent document 1 as a weft cutting device, in such a weft cutting device, a plunger is driven so as to reciprocate in a cylinder at a speed of several hundreds times per minute.

In addition, this weft cutting device is configured such that a plunger is disposed in a cylinder so that an outer peripheral surface thereof is in contact with an inner peripheral surface of the cylinder, and the plunger is slidably guided by the cylinder in accordance with the reciprocating movement. Therefore, as the plunger reciprocates in the cylinder at a speed of several hundred times per minute as described above, abrasion occurs between the plunger and the cylinder (tool holder). When such abrasion occurs, the plunger cannot smoothly reciprocate in the cylinder, and as a result, there is a problem that the weft yarn is not cut at a desired timing or the weft yarn is not cut.

Here, in order to prevent such a problem, when the wear as described above occurs, it is necessary to replace the worn portion. However, such wear occurs not only in the plunger that reciprocates in the cylinder but also in the cylinder-side portion that slidably guides the plunger. Further, the inventors of the present invention have found from experiments that such wear of the cylinder side occurs in the plunger of any material. Therefore, when such wear occurs, the entire tool holder including the cylinder side is replaced. That is, the blade holder as the main body portion of the weft cutting device is replaced. Therefore, the use of such a weft cutting device requires high maintenance costs.

The weft cutting device disclosed in patent document 1 is configured such that a cylindrical sleeve (sleeve) is fitted into a cylinder, and a plunger is slidably guided by the sleeve. As a result, the cylinder side wear on the sleeve can occur. Further, although not specifically mentioned in patent document 1, since the plunger reciprocating at a high speed is to be guided, the sleeve should be firmly fixed to the cylinder (holder). Therefore, as described above, even when the sleeve is worn, the tool holder needs to be replaced.

In view of the above circumstances, an object of the present invention is to provide a weft cutting device for a loom in which a plunger reciprocates to oscillate a movable blade by supplying and discharging air as described above, in which the wear of a cylinder, which is a cause of high maintenance cost, is less likely to occur.

Means for solving the problems

The present invention is premised on a weft cutting device of a loom that swings a movable blade by reciprocating a plunger by supplying air into a cylinder as described above.

Further, the weft cutting device according to the present invention includes a guide portion provided in the cylinder so as to extend in a longitudinal direction of the cylinder. In the weft cutting device, the plunger is provided to be slidably guided by the guide portion in a guide hole formed in parallel with the longitudinal direction in a state of being accommodated in the cylinder.

In the weft cutting device according to the present invention, the guide hole is a bottomed hole having a bottom surface and being open to a pressure receiving surface that is an end surface on one end side of the plunger, and the guide portion is provided so as to extend from an inner end surface of the cylinder facing the pressure receiving surface of the plunger toward the inside of the cylinder. In the weft cutting device, the movable blade is located at a swing limit on one side of a desired swing range in a state where the bottom surface of the guide hole of the plunger is in contact with an end surface of the guide portion and/or in a state where the inner end surface of the cylinder is in contact with the pressure receiving surface of the plunger. Further, this weft cutting device has a communication passage formed to communicate a space formed between the bottom surface of the guide hole and the end surface of the guide portion in association with the reciprocating movement with the outside of the plunger, and the communication passage is formed so that the space is in a negative pressure state in accordance with a relationship between a volume change of the space in association with the reciprocating movement and an amount of air flowing into the space due to the volume change.

Effects of the invention

According to the weft cutting device of the present invention, since the plunger is slidably guided by the guide portion in the guide hole formed inside thereof and reciprocates, it is not necessary to configure the plunger and the cylinder such that the outer peripheral surface of the plunger is slidably guided by the cylinder housing the plunger. Therefore, according to such a weft cutting device, the cylinder portion including the plunger can be configured such that the outer peripheral surface of the plunger does not abut against the inner peripheral surface of the cylinder. By configuring the weft cutting device in this manner, only the plunger and the guide portion are worn away with the reciprocating movement of the plunger. Therefore, the parts to be replaced together with the plunger along with the occurrence of the wear are the guide portions provided separately from the inner peripheral surface thereof, rather than the tool holders including the inner peripheral surface of the cylinder, and therefore, the maintenance cost using such a weft cutting device can be reduced.

In addition, by setting the weft cutting device of the present invention to have the communication passage as described above, the space as described above is formed in the plunger in association with the reciprocating movement of the plunger, and the space becomes a negative pressure state in association with the reciprocating movement, so that the service life of the plunger can be extended. Specifically, the volume of the space in the plunger changes with the displacement of the plunger from the position at which the movable blade is positioned at the swing limit on one side of the desired swing range. Further, the air flows into the space from the communication passage with the change in the volume thereof, but the space is in a negative pressure state because the communication passage is formed as described above. As a result, when the movable blade reaches the oscillation limit of the other side from the oscillation limit of the one side, the plunger receives less impact, and therefore the service life of the plunger can be prolonged.

Drawings

Fig. 1 is a schematic view showing an example of a loom provided with a weft cutting device according to the present invention;

FIG. 2 is a front view showing an example of a weft cutting device according to the present invention;

FIG. 3 is a left side view of FIG. 2;

fig. 4 is a partially enlarged sectional view showing the cylinder of fig. 2.

In the drawings

1-loom, 2-warp row, 3-reed, 4-tucking device, 5-tucking head, 6-support shaft, 7-swing arm, 8-side stay, 9-support mechanism, 10-weft cutting device, 11-scissors, 12-fixed knife, 12 a-knife section, 12a 1-knife edge, 12 b-base, 13-movable knife, 13 a-knife section, 13a 1-knife edge, 13 b-portion extending to the other end side, 14-knife holder, 14 a-mounting section, 14 b-cylinder forming section, 14 c-cylinder hole, 14c 1-bottom of cylinder hole, 14c 2-inner peripheral surface of cylinder hole, 14c 3-inner peripheral surface of opening side portion, 14 d-opening section, 14 e-one air flow path, 14 f-another air flow path, 15-pivot, 16-displacement rod, 16 a-disk-shaped section, 16a 1-third through hole, 16 b-one protrusion (one end portion), 16b 1-a fourth through hole, 16 c-another protrusion (another end), 16c 1-a side surface of the other end, 17-a connecting shaft, 18-a plunger, 18 a-an end surface on one side (a pressure receiving surface on one side), 18 b-an end surface on the other side (a pressure receiving surface on the other side), 18 c-an outer peripheral surface of the plunger, 18 d-a concave portion, 18 e-a groove portion, 18e 1-an inner side surface of the groove portion, 18e 2-a bottom surface of the groove portion, 18 f-an insertion hole (guide hole), 18f 1-a bottom surface of the insertion hole (guide hole), 18f 2-an inner peripheral surface of the insertion hole (guide hole), 19-a lid member, 19 a-a lid member, 19 b-a flange portion, 19b 1-an end surface of the flange portion, 19 c-an outer thread portion, 19c 1-an inner end surface of the cylinder (an end surface of the outer thread portion), 19 d-a hexagonal hole, 19, 19e 2-outer peripheral surface of extension (guide), 19 f-through hole (communication channel), 20-cylinder, 21-air supply mechanism, 21 a-air supply device, 21 b-supply pipe, 21 c-pipe joint, 22-space in plunger, T-cloth, CL-center line of cylinder hole.

Detailed Description

An embodiment of a weft cutting device according to the present invention will be described below with reference to fig. 1 to 4. In the present embodiment, it is assumed that the weft cutting device 10 is attached to the tucking head 5 and cuts the inserted weft yarn so that the weft yarn of a predetermined length is tucked.

As shown in fig. 1, in the present embodiment, the loom 1 includes a tuck-in head 5 disposed adjacent to the woven cloth T (warp row 2) in the fabric width direction. The tuck-in head 5 is a tuck-in head in which the end of the weft inserted is tucked back into the warp opening by air jet. In the present embodiment, the tucking device 4 including the tucking head 5 is a tucking device of a type that drives the tucking head 5 to reciprocate in the front-rear direction of the loom 1 so as to avoid interference with the swinging reed 3. The tuck-in head 5 is attached to the other end side of a swing arm 7 whose one end side is swingably supported by a support shaft 6 disposed on the loom 1. The folding device 4 is configured to drive the folding head 5 to reciprocate by swinging the swinging arm 7 by a driving mechanism (not shown). The support shaft 6 supporting the swing arm 7 is supported by a support mechanism 9, and the support mechanism 9 is provided upright on a temple bar 8 provided in the loom 1 so as to extend in the fabric width direction.

The weft cutting device 10 is supported together with the tuck-in head 5 on the other end side of the swing arm 7. Specifically, the weft cutting device 10 includes a tool holder 14 as a base for supporting the fixed blade 12 and the movable blade 13, and the tool holder 14 is attached to the swing arm 7. More specifically, the holder 14 is formed in a plate shape, and includes an attachment portion 14a that is long in one direction and a cylinder forming portion 14b provided on one end side in the longitudinal direction of the attachment portion 14a as viewed in the plate thickness direction.

The cylinder forming portion 14b is formed in a substantially rectangular parallelepiped shape in appearance, and has a cylinder hole 14c for accommodating the plunger 18. The cylinder bore 14c is formed so that the direction of the center line CL (center line direction) coincides with the longitudinal direction of the cylinder forming portion 14b (longitudinal direction of the side surface, hereinafter simply referred to as "longitudinal direction"), and is formed so as to open and extend in the longitudinal direction only in one of the end surfaces on both sides of the cylinder forming portion 14b in the longitudinal direction.

In the holder 14, the mounting portion 14a and the cylinder forming portion 14b are integrally formed in a state where the longitudinal direction of the cylinder forming portion 14b and the plate width direction of the mounting portion 14a are substantially aligned. However, the mounting portion 14a and the cylinder forming portion 14b are positioned such that one side surface of the cylinder forming portion 14b overlaps with one plate surface of the mounting portion 14 a. That is, the mounting portion 14a is located closer to one side surface side of the cylinder forming portion 14b than the center of the cylinder hole 14c, as viewed from the longitudinal direction of the cylinder forming portion 14 b.

Further, regarding the fixed blade 12 and the movable blade 13 supported by the holder 14, the fixed blade 12 is configured by a blade portion 12a and a base portion 12b, the blade portion 12a is a plate-shaped blade body formed with a blade edge 12a1 for cutting a weft yarn, and the base portion 12b is integrally formed with the blade portion 12a for attaching the fixed blade 12 to the holder 14. The fixed blade 12 is formed into a substantially L-shape by the base portion 12b and the blade portion 12 a. In the fixed blade 12, the cutting edge 12a1 of the cutting portion 12a is formed at an inner end edge of the L-shaped fixed blade 12.

The fixed blade 12 is fixed at its base 12b to the one plate surface of the mounting portion 14 a. However, the fixing to the mounting portion 14a is performed in such a manner that the extending direction of the blade portion 12a (blade 12a1) and the longitudinal direction of the mounting portion 14a are substantially orthogonal to each other, and the blade 12a1 faces the other end side of the mounting portion 14 a. As a result, in the weft cutting device 10, the extending direction of the blade portion 12a (blade 12a1) of the fixed blade 12 and the longitudinal direction of the cylinder forming portion 14b substantially coincide with each other, and the fixed blade 12 is in a state of facing the cylinder forming portion 14b at the end edge on the opposite side to the blade 12a1 side of the blade portion 12 a.

In the weft cutting device 10, the pivot shaft 15 is provided in the vicinity of the boundary between the base portion 12b and the blade portion 12a of the fixed blade 12 so as to protrude in the plate thickness direction of the fixed blade 12 in the state where the fixed blade 12 is attached to the blade holder 14 as described above.

The movable blade 13 is similarly a plate-shaped blade body, and has a through hole (first through hole, not shown) formed to penetrate in the plate thickness direction at substantially the center thereof. The movable blade 13 is formed such that a portion extending to one end side of the first through hole is a blade portion 13a having a blade edge 13a 1. The movable blade 13 is supported by the pivot shaft 15 so that the pivot shaft 15 is inserted through the first through hole and is swingable. However, in such a supported state, the movable knife 13 is in the following state: the extending direction of the blade portion 13a with respect to the first through hole coincides with the extending direction of the blade portion 12a of the fixed blade 12 with respect to the pivot 15, and the cutting edge 13a1 of the blade portion 13a faces the fixed blade 12 side.

The movable blade 13 also has a through hole (second through hole, not shown) formed to penetrate in the plate thickness direction at a portion 13b extending to the other end side of the first through hole. The second through hole is formed on the end edge side of the other end away from the first through hole.

The weft cutting device 10 further includes a shift lever 16 for swinging the movable blade 13. The displacement rod 16 is a rod-shaped member, and has two projections 16b and 16c formed to project in the radial direction from the disk-shaped portion 16 a. That is, the shift lever 16 is formed such that one projection 16b of the two projections 16b and 16c corresponds to one end of the lever and the other projection 16c corresponds to the other end of the lever. The shift lever 16 has a through hole (third through hole) 16a1 formed at the center of the disk-shaped portion 16a so as to penetrate in the plate thickness direction. Further, a through hole (fourth through hole) 16b1 is formed in the one end portion 16 b. In the shift lever 16, one end portion 16b and the other end portion 16c are formed such that their extending directions (projecting directions) are substantially orthogonal to each other.

The shift lever 16 is swingably supported by the pivot shaft 15 so that the pivot shaft 15 is inserted through the third through hole 16a 1. The shift lever 16 is connected to the movable knife 13 at one end 16b thereof. More specifically, the connecting shaft 17 is inserted into a fourth through hole 16b1 formed in the one end 16b of the shift lever 16. Then, the connecting shaft 17 is inserted into a second through hole formed in the other end side of the movable blade 13 and the inserted state is fixed (the state is set to the disengagement prevention state), whereby the one end 16b of the shift lever 16 and the other end side of the movable blade 13 are connected, and the shift lever 16 is connected to the movable blade 13.

However, the displacement rod 16 is supported so that the other end portion 16c of the rod extends toward the cylinder forming portion 14b side in a state where the displacement rod 16 is connected to the movable blade 13. That is, as described above, in a state where the shift lever 16 is supported by the pivot shaft 15 and connected to the movable blade 13, the other end portion 16c of the shift lever 16 extends toward the cylinder forming portion 14b of the tool holder 14. In this state, the other end portion 16c has a length extending into the cylinder bore 14c of the cylinder forming portion 14 b.

On the other hand, the cylinder forming portion 14b is formed with an opening portion 14d, and the opening portion 14d is a hole that communicates the cylinder hole 14c with the outside, and opens on the side surface opposite to the one side surface and the side surface facing the stationary blade 12. Therefore, as described above, in the state where the shift lever 16 is supported, the weft cutting device 10 is in a state where the other end portion 16c of the shift lever 16 is inserted into the cylinder hole 14c from the opening portion 14 d.

In the weft cutting device 10, the movable blade 13 and the shift lever 16 are supported by the pivot shaft 15 protruding from the fixed blade 12 in the plate thickness direction as described above, but the movable blade 13 and the shift lever 16 are supported in order in the protruding direction of the pivot shaft 15. The shift rod 16 is disposed so that the position of the plate surface facing the movable blade 13 and the center position of the cylinder hole 14c of the cylinder forming portion 14b substantially coincide with each other in the plate thickness direction. In the displacement rod 16, the other end 16c extends to an end edge on the tip end side beyond the center line CL of the cylinder hole 14 c.

The weft cutting device 10 is configured such that the other end 16c of the shift lever 16 engages with a plunger 18 provided in a cylinder hole 14c of the cylinder forming portion 14 b. Details of this structure are as follows. However, in the present embodiment, the plunger 18 is formed of a single member and has a groove 18e for engaging with the other end 16c of the displacement rod 16.

The plunger 18 is a shaft-like member formed in a substantially cylindrical shape. The plunger 18 is formed such that its outer diameter is slightly smaller than the inner diameter of the cylinder bore 14 c. The plunger 18 is formed with a groove 18e, which is a portion for performing the above-described engagement. The groove 18e is formed to open to the outer peripheral surface 18c of the plunger 18, and the inner surfaces 18e1, 18e1 of the groove 18e are perpendicular to the axial direction of the plunger 18.

The plunger 18 is accommodated in the cylinder bore 14c in such a manner that the bottom surface 18e2 of the groove 18e is parallel to the plate surface of the displacement rod 16. Then, the plunger 18 and the shift lever 16 are engaged with each other as follows: the other end 16c of the shift lever 16 is inserted into the groove 18e of the plunger 18, and both side surfaces 16c1, 16c1 of the other end 16c abut against the inner side surfaces 18e1, 18e1 of the groove 18 e. Therefore, the size of the groove width (the interval between the inner surfaces 18e1 and 18e 1) of the groove portion 18e substantially matches the plate width (the interval between the two side surfaces 16c1 and 16c 1) of the other end portion 16c of the shift lever 16.

The groove 18e is formed such that the bottom surface 18e2 of the groove 18e is located at a depth substantially near the axis of the plunger 18. Thus, in the engaged state as described above, the plunger 18 and the shift lever 16 are in a state in which the position of the bottom surface 18e2 of the groove portion 18e and the position of the plate surface on the movable blade 13 side of the shift lever 16 are substantially aligned in the plate thickness direction of the shift lever 16. However, the groove 18e is formed at a position in the axial direction of the plunger 18 at which the reciprocating movement of the plunger 18 is permitted even in a state where the plunger 18 and the shift lever 16 are engaged as described above. The plunger 18 has the following length dimension in the axial direction: in a state where one end surface 18a of the two end surfaces is in contact with the bottom surface 14c1 of the cylinder hole 14c, the other end surface 18b opposite to the one end surface 18a is positioned on the opening side of the cylinder hole 14c with respect to the opening portion 14d of the cylinder forming portion 14 b.

Further, a cover member 19 is attached to the cylinder forming portion 14b of the tool holder 14 to close the cylinder hole 14 c. More specifically, the lid member 19 has a substantially cylindrical lid portion 19a, and the cylinder hole 14c is closed by attaching the lid portion 19a to the cylinder forming portion 14 b. The lid portion 19a is formed such that a portion on one end side in the axial direction is a flange portion 19b having a larger diameter than the cylinder hole 14c, and a portion on the other end side is a male screw portion 19c having a male screw formed on an outer peripheral surface thereof. On the other hand, the inner peripheral surface 14c3 of the cylinder bore 14c on the opening side thereof is internally threaded. The lid member 19 is attached to the cylinder forming portion 14b in a state where the male screw portion 19c of the lid portion 19a is screwed into the cylinder hole 14c and the screw is tightened until the flange portion 19b comes into contact with the cylinder forming portion 14 b. The cap member 19 has a hexagonal hole 19d formed so as to open to the end face 19b1 of the flange portion 19b, and a tool is inserted into the hexagonal hole 19d to perform the above-described screwing operation.

The cover 19a and the cylinder forming part 14b of the cover member 19 form a cylinder 20 of the weft cutting device 10. The weft cutting device 10 further includes an air supply mechanism 21 including an air supply device 21a, and the air supply device 21a supplies compressed air into the cylinder 20 to reciprocate the plunger 18. The air supply mechanism 21 is described in detail below.

First, the mounting portion 14a of the holder 14 is configured such that the dimension of the one end side portion in the plate width direction is larger than the dimension of the other end side portion in the plate width direction. The size of the portion on the one end side is such that the holder 14, in which the mounting portion 14a and the cylinder forming portion 14b are integrally formed as described above, is present over the entire range including the range in which the cylinder hole 14c of the cylinder forming portion 14b is present in the plate width direction. The other end portion is formed in the vicinity of the center of the one end portion in the plate width direction. Therefore, the mounting portion 14a is formed such that a portion on the one end side bulges out to both sides with respect to the other end side in the board width direction.

The holder 14 has two air flow paths 14e and 14f formed so as to open at the end surfaces of the bulging portions (bulging portions) on the two sides of the mounting portion 14a and communicate with the cylinder hole 14 c. One air flow path 14e of the two air flow paths 14e and 14f is formed to open at a bottom surface 14c1 of the cylinder hole 14 c. In contrast, the other air flow path 14f is formed to communicate with the cylinder hole 14c in the vicinity of the lid portion 19a of the lid member 19 (the inner end surface 19c1 of the cylinder 20 formed by the lid portion 19 a).

The air supply device 21a is provided in the loom 1 so as to be fixed to a frame (not shown) of the loom 1. The air supply device 21a and the tool holder 14 (cylinder 20) are connected via flexible supply pipes 21b and 21b such as hoses. The supply pipes 21b and 21b are connected to the holder 14 via pipe joints 21c and 21c such as screw joints attached to the bulging portion of the mounting portion 14 a. The air supply mechanism 21 is constituted by the supply pipes 21b and 21b connected to the tool holder 14, the air supply device 21a, and the like.

In the weft cutting device 10 configured as described above, the air supply mechanism 21 supplies compressed air from the air flow paths 14e and 14f into the cylinder 20, thereby reciprocating the plunger 18 in the cylinder 20. More specifically, by supplying compressed air from the one air flow passage 14e into the cylinder 20, the one end surface 18a of the plunger 18 receives the pressure as a pressure receiving surface (one pressure receiving surface), and the plunger 18 moves toward the cover 19 a. Further, by supplying compressed air into the cylinder 20 from the other air flow path 14f, the other end surface 18b of the plunger 18 receives the pressure as a pressure receiving surface (the other pressure receiving surface), and thereby the plunger 18 moves back toward the bottom surface 14c1 of the cylinder hole 14 c. Then, the displacement rod 16 engaged with the plunger 18 is driven to swing in accordance with the reciprocating movement of the plunger 18. Thereby, the movable knife 13 connected to the shift lever 16 is driven to swing throughout a desired swing range.

In the weft cutting device 10 as described above, the weft cutting device according to the present invention includes a guide portion for slidably guiding the plunger. In the present embodiment, the guide portion 19e is disposed on the cover member 19 as a part of the cover member 19. The guide portion 19e is described in detail below.

First, the lid member 19 has a rod-like extension 19e extending in the axial direction of the lid member 19a from an end surface (a surface that becomes an inner end surface of the cylinder 20) 19c1 of the male screw portion 19c of the lid member 19 a. The extension portion 19e is formed in a cylindrical shape (round bar shape) and is formed at a position where its axial center coincides with the axial center of the lid portion 19a when viewed in the axial direction thereof. Also, the extension 19e has the following length dimensions: in the state where the cap member 19 is attached to the cylinder forming portion 14b as described above, the end surface 19e1 is located substantially at the middle between the inner end surface 19c1 of the cylinder 20 and the bottom surface 14c1 of the cylinder hole 14 c.

On the other hand, the plunger 18 is formed with an insertion hole 18f, and the insertion hole 18f is opened only in the pressure receiving surface 18b on the other side and into which the extending portion 19e is inserted. The insertion hole 18f is formed at a position where the center thereof coincides with the axial center of the plunger 18 when viewed in the direction of the center line. The insertion hole 18f is formed in a hole such that the inner peripheral surface 18f2 thereof and the outer peripheral surface 19e2 of the extension portion 19e are in sliding contact with each other in a state where the extension portion 19e is inserted therein.

In the weft cutting device 10, the plunger 18 is accommodated in the cylinder 20 as described above, the extending portion 19e of the cover member 19 is inserted into the insertion hole 18f, and the plunger 18 is supported by the extending portion 19 e. Further, in this state, some clearance is formed between the outer peripheral surface 18c of the plunger 18 and the inner peripheral surface 14c2 of the cylinder hole 14 c. In this state, the insertion hole 18f is parallel to the center line direction of the cylinder hole 14c (the longitudinal direction of the cylinder 20). The insertion hole 18f is formed to have a depth (dimension in the axial direction of the plunger 18) as follows so as not to hinder the reciprocating movement of the plunger 18 in the cylinder 20: in a state where the plunger 18 abuts against the bottom surface 14c1 of the cylinder hole 14c, the bottom surface 18f1 of the insertion hole 18f and the end surface 19e1 of the extension portion 19e are separated from each other.

In the weft cutting device 10 configured as described above, the plunger 18 is reciprocatingly movable in the longitudinal direction of the cylinder 20 in a state of being supported by the extending portion 19e of the cover member 19 in the insertion hole 18f as described above, and the reciprocatingly movable is slidably guided by the extending portion 19 e. Therefore, in the weft cutting device 10, the extending portion 19e of the cover member 19 corresponds to a "guide portion" in the present invention, and the insertion hole 18f of the plunger 18 corresponds to a "guide hole".

The depth of the insertion hole (guide hole) 18f is set so that the pressure receiving surface 18b on the other side of the plunger 18 is positioned closer to the opening 14d of the cylinder forming portion 14b than the other air flow path 14f in a state where the bottom surface 18f1 of the guide hole 18f and the end surface 19e1 of the guide portion 19e are in contact with each other. Thus, the weft yarn cutting device 10 is configured such that the displacement of the plunger 18 toward the cover 19a is restricted to a predetermined position by the guide 19e so that the other air flow passage 14f is not blocked by the plunger 18.

The lid member 19 is formed with a through hole 19f that penetrates the guide portion 19e in the axial direction and has a center that coincides with the axial center of the guide portion 19e when viewed in the axial direction. Therefore, as the plunger 18 reciprocates, the space (space inside the plunger 18) 22 formed between the bottom surface 18f1 of the guide hole 18f and the end surface 19e1 of the guide portion 19e communicates with the outside of the cylinder 20 (outside the plunger 18) via the through hole 19 f. Therefore, the through hole 19f functions as a "communication passage". Accordingly, as the volume of the space 22 changes when the plunger 18 reciprocates in the cylinder 20, air flows into the space 22 through the communication passage 19f and air flows out of the space 22. The reciprocating movement of the plunger 18 in which the volume change occurs is performed at a speed at which the loom 1 reciprocates once per cycle.

However, the size of the diameter of the communication passage 19f is such that the amount of air flowing from the communication passage 19f corresponds to the amount that causes the space 22 to be in the negative pressure state in association with the displacement of the plunger 18 toward the bottom surface 14c1 side of the cylinder bore 14c, based on the relationship between the change rate (the amount of change per unit time) of the volume change of the space 22 in the plunger 18 and the same. Thus, during the return movement, the space 22 in the plunger 18 is under negative pressure. Further, according to this structure, the space 22 in the plunger 18 is in a positive pressure state at the time of the forward movement.

In the weft cutting device 10 configured as described above, in a state where the plunger 18 abuts the bottom surface 14c1 of the cylinder hole 14c with the one pressure receiving surface 18a, the movable blade 13 is positioned at the swing limit on the one side of the desired swing range, and the scissors 11 composed of the movable blade 13 and the fixed blade 12 are in the most open state. In this state, when the air supply mechanism 21 starts to supply compressed air into the cylinder 20 from the one air flow path 14e, the pressure of the compressed air acts on the pressure receiving surface 18a on the one side of the plunger 18, and the plunger 18 starts the forward movement. The concave portion 18d is formed on the pressure receiving surface 18a on the one side of the plunger 18 that receives the pressure of the compressed air, and when the forward movement starts, the plunger 18 receives the pressure of the compressed air through the concave portion 18 d.

Thereafter, the plunger 18 is displaced toward the lid 19a while being guided by the guide portion 19e in the guide hole 18f, and the displacement is stopped when the bottom surface 18f1 of the guide hole 18f abuts against the end surface 19e1 of the guide portion 19 e. Then, the movable blade 13 swings toward the other swing limit of the swing range in accordance with the displacement of the plunger 18 toward the cover 19a, and the scissors 11 cut the weft yarn.

Then, the air supply mechanism 21 stops the supply of the compressed air from the one air flow path 14e, and starts the supply of the compressed air from the other air flow path 14f into the cylinder 20. Thereby, the plunger 18 is in a state of receiving the pressure of the compressed air on the pressure receiving surface 18b on the other side, and the plunger 18 starts the return movement from the position at which it was stopped as described above. The plunger 18 is guided by the guide portion 19e and displaced toward the bottom surface 14c1 side of the cylinder bore 14c as described above, and when the pressure receiving surface 18a on the one side comes into contact with the bottom surface 14c1, the displacement is stopped. As a result, the scissors 11 are again in the most open state.

Thus, according to the weft cutting device 10, the sliding guide of the plunger 18 during the reciprocating movement in the cylinder 20 is guided only by the guide portion 19e that supports the plunger 18 on the inner side (guide hole 18f) of the plunger 18, and is not guided by the outer peripheral surface 18c of the plunger 18 as in a normal cylinder or the like. Thus, the inner peripheral surface 14c2 (the cylinder forming portion 14b) of the cylinder hole 14c of the tool holder 14 is not worn along with the slide guide. The guide portion 19e is worn along with the sliding guide, but the guide portion 19e is included in the cap member 19 that is detachable from the cylinder forming portion 14b (the tool seat 14) as described above. Therefore, when the worn portion is replaced, the blade holder 14 does not need to be replaced, and only the cover member 19 needs to be replaced, so that the maintenance cost of the weft cutting device 10 can be reduced.

Further, at the time of the forward movement of the plunger 18, the air existing between the pressure receiving surface 18b on the other side and the end surface (inner end surface of the cylinder 20) 19c1 of the cap 19a is discharged to the outside through the gap between the plunger 18 and the cylinder hole 14c, the air in the space 22 in the plunger 18 is discharged to the outside through the communication passage 19f, and the space 22 in the plunger 18 becomes a positive pressure state along with the forward movement as described above. During the return movement, the air existing between the pressure receiving surface 18a on the one side and the bottom surface 14c1 of the cylinder hole 14c is discharged to the outside through the gap, and the outside air flows into the space 22 in the plunger 18 through the communication passage 19f, but as described above, the space 22 in the plunger 18 becomes a negative pressure state along with the return movement. This alleviates the impact when the plunger 18 collides with the end face 19e1 of the guide 19e during the forward movement of the plunger 18 or when the plunger 18 collides with the bottom face 14c1 of the cylinder bore 14c during the return movement of the plunger 18, and therefore the service life of the plunger 18 can be extended.

The present invention is not limited to the above-described embodiments, and may be modified as shown in the following (1) to (6).

(1) Regarding the guide portion for guiding the reciprocating movement of the plunger and the guide hole of the plunger, in the above embodiment, the guide portion 19e is formed in a cylindrical shape, and the guide hole 18f is formed in a hole diameter such that its inner peripheral surface 18f2 and the outer peripheral surface 19e2 of the guide portion 19e are in sliding contact. That is, in the above embodiment, the cross-sectional shape of the guide portion 19e and the hole shape of the guide hole 18f are both formed in a circular shape (substantially circular shape). However, in the present invention, the cross-sectional shape of the guide portion and the hole shape of the guide hole are not limited to such a circular shape, and at least one of the cross-sectional shape and the hole shape may be a non-circular shape.

For example, the cross-sectional shape of the guide portion and the hole shape of the guide hole may be both of the same elliptical shape or polygonal shape (such as a square or regular hexagon). Further, the shape of the guide hole is not limited to the same shape, and for example, the shape of the guide hole may be a substantially circular shape, and the cross-sectional shape of the guide portion may be an elliptical shape or a polygonal shape in which two or more points on the outer periphery are in contact with the inner peripheral surface of the guide hole, as in the above-described embodiment. In this case, in order to further increase the contact area, it is preferable that a portion of the guide portion that contacts the inner circumferential surface of the guide hole on the outer circumferential surface of the guide portion is an arc surface having the same curvature as the inner circumferential surface of the guide hole. Further, even when the shapes of the guide hole and the guide hole are different from each other, the shape of the guide hole is not limited to one of the guide hole and the guide hole, and for example, the guide hole may have an elliptical shape and the cross-sectional shape of the guide portion may have a polygonal shape in which two or more corners of the outer periphery are in contact with the inner peripheral surface of the guide hole.

In the case of the structure in which the cross-sectional shape of the guide portion and the hole shape of the guide hole are made different from each other as described above, a plurality of spaces are present between the periphery of the outer peripheral surface of the guide portion and the inner peripheral surface of the guide hole. The space communicates with a space formed between the end surface of the guide portion and the bottom surface of the guide hole in accordance with the reciprocating movement of the plunger, and communicates with a space between the plunger and the cover portion (outside the plunger). Therefore, since the plurality of spaces around the guide portion function as the communication passages, the through-holes that function as the communication passages with respect to the guide portion (the cover member) as in the above-described embodiment may not be provided in such a configuration.

On the other hand, in the case of the structure in which the cross-sectional shape of the guide portion and the hole shape of the guide hole are made the same as described above, a through-hole may be formed in the guide portion as in the above-described embodiment, and the through-hole may function as a communication passage. However, in the case where the cross-sectional shape of the guide portion and the hole shape of the guide hole are the same shape as in the case of the above-described embodiment or the structure, the communication passage is not limited to such a through hole formed in the guide portion, and may be at least one of a groove formed in the guide portion so as to extend in the axial direction and open to the outer circumferential surface and a groove formed in the plunger so as to extend in the direction of the center line of the guide hole and open to the inner circumferential surface of the guide hole. In the case where both of the guide holes have the same shape, the communicating path may be a through hole formed in the plunger, and the through hole may be opened to the inner peripheral surface of the guide hole at a position closest to the bottom surface of the guide hole in the direction of the center line of the guide hole.

In the communication passage described above, it is preferable that the amount of air flowing from the communication passage into the space in the plunger in accordance with the return movement of the plunger is equivalent to the amount of air in which the space is brought into a negative pressure state, as in the above-described embodiment. However, in the present invention, the communication passage is not limited to the passage formed so that the space in the plunger becomes a negative pressure state in association with the return movement, and may be formed so that air of an amount corresponding to a change in the volume of the space in the plunger can flow into the space without resistance in association with the return movement.

(2) In the plunger as a component for swinging the shift lever, in the above-described embodiment, the plunger 18 is formed of a single member and has the groove portion 18e, and the shift lever 16 is engaged with the groove portion 18 e. However, in the present invention, the plunger is not limited to being constituted by such a single member, and may be constituted by two members (plunger constituting members) disposed on both sides of the other end portion of the displacement rod in the center line direction of the cylinder hole.

Specifically, in the case where the plunger is formed by using two plunger forming members each formed of a single columnar member, the two plunger forming members are disposed on both sides of the other end portion of the displacement rod in the cylinder. The other end of the displacement rod is sandwiched between the two plunger constituting members, whereby the plunger and the displacement rod are engaged with each other.

In addition, in the case where the plunger is constituted by two plunger constituting members as described above, it is necessary to reciprocate the two plunger constituting members by sliding guide of the guide portion. Here, for example, two plunger constituent members are formed as bottomed guide holes like the plunger 18 of the embodiment. The structure for slidably guiding the reciprocation of one plunger constituent member is the same as that of the above-described embodiment, and the structure for slidably guiding the reciprocation of the other plunger constituent member may be the same as that for slidably guiding the reciprocation of the one plunger constituent member.

Specifically, the cylinder forming portion has a cylinder hole formed to penetrate through the cylinder forming portion in the longitudinal direction thereof, in order to slidably guide the other plunger constituting member to reciprocate. Further, a lid member configured similarly to the lid member 19 of the above-described embodiment is attached to the cylinder forming portion so as to close the cylinder hole on the opposite side of the lid member that slidably guides the reciprocation of the one plunger constituting member in the longitudinal direction of the cylinder forming portion. The other plunger constituent member is guided by the guide portion of the cap member attached to the cylinder forming portion in this manner in the guide hole. In this configuration, the one air flow passage may be formed so as to communicate with the cylinder hole in the vicinity of the lid portion of the lid member, similarly to the other air flow passage.

In addition, when the plunger is configured by two plunger configuring members, the two plunger configuring members may be configured to be guided by a common guide portion. Specifically, the cylinder hole is a bottomed hole as in the above-described embodiment, and the cylinder hole is closed with a lid member as in the above-described embodiment. However, the guide portion of the cover member has the following length dimensions: the cylinder extends to the bottom surface side of the cylinder hole than the position where the other end of the displacement rod is present.

In addition, the two plunger constituent members are formed such that the plunger constituent member disposed on the cover portion side with respect to the other end portion of the displacement rod has a guide hole penetrating in the axial direction. On the other hand, the guide hole is set as the bottomed hole as described above with respect to the plunger constituent member disposed on the bottom surface side of the cylinder hole. Also, the following structure may be considered: the cylinder component on the cover side is arranged in a state that the guide part is inserted into the guide hole, and the cylinder component on the bottom side is arranged in a state that the guide part is inserted into the guide hole, so that the other end part of the displacement rod is positioned between the two plunger component. The guide portion has a length dimension such that the movable knife is positioned at the other swing limit in a state where the end surface of the guide portion is in contact with the bottom surface of the guide hole of the plunger constituting member on the bottom surface side.

In the structure in which the two plunger constituting members are guided by the single guide portion, the guide hole of the plunger constituting member on the bottom surface side may be formed as a through hole, similarly to the plunger constituting member on the cover portion side.

In these configurations, since the guide portion is configured to pass through the range in which the displacement rod is present in the cylinder, it is necessary to configure the guide portion and/or the displacement rod so as not to interfere with each other. As such a structure, for example, a groove or the like that allows the displacement lever to swing may be formed at a position overlapping the displacement lever in the guide portion.

In these configurations, the stop of the displacement of the plunger constituent member on the cover portion side during the forward movement is achieved by the contact between the inner end surface of the cylinder (the end surface of the cover portion) and the pressure receiving surface of the plunger constituent member. In this case, when the other air flow path is formed at the position as in the above-described embodiment, the compressed air from the air flow path is supplied to the outer peripheral surface of the plunger constituent member, and therefore, the other air flow path may be formed so as to be opened, for example, at the end surface of the lid portion. In the case of the structure in which the guide hole in the plunger constituent member on the bottom surface side is formed as the through hole as described above, the one air flow passage may be formed so as to be opened in a portion of the bottom surface of the cylinder hole which is in contact with the plunger constituent member on the bottom surface side, for example.

(3) As for the guide portion for slidably guiding the plunger, in the above-described embodiment, the guide portion 19e is constituted by an extension portion formed to extend in the axial direction at the lid portion, and is formed in a single rod shape. However, in the present invention, the guide portion is not limited to being constituted by a single extension portion as described above, and may be constituted by a plurality of extension portions extending in the axial direction from a portion (cover portion) of the cylinder forming portion attached to the cover member. That is, in the case of such a configuration, the guide portion is constituted by the plurality of extending portions.

In the case where the guide portion is constituted by a plurality of extending portions as described above, the guide hole in the plunger to be slidably guided by the guide portion may be constituted by the same number of holes as the extending portions, or may be constituted by a single hole as in the above-described embodiment. However, when the guide hole is formed of a single hole as described above, the plurality of extending portions are arranged such that all the extending portions simultaneously contact the inner peripheral surface of the guide hole.

(4) As for the guide portion that slidably guides the plunger, in the embodiment, this guide portion 19e is formed integrally with the cap portion 19a that is detachable with respect to the cylinder forming portion 14 b. That is, in the embodiment, the guide portion 19e is formed as a part of the cover member 19, the cover member 19 including the cover portion 19a and constituting a part of the cylinder 20. However, in the present invention, the guide portion is not limited to being formed as a part of the cover member as described above, and may be formed as a member separate from the cover member and attached to the cylinder.

More specifically, the lid member is constituted only by the lid portion. In addition, as the guide portion, a member (guide portion forming member) having a rod-shaped portion (rod-shaped portion) functioning as the guide portion may be provided separately from the cover member, and the guide portion forming member may be attached to the cylinder (cover member).

As such a configuration, for example, the lid member is configured only by the lid member as described above, and the through hole is formed as a hole penetrating in the axial direction thereof, and the rod-like portion of the guide forming member is fitted therein. The guide forming member has a flange portion formed on one end side of the rod-shaped portion. Further, the rod-shaped portion of the guide forming member is fitted into the through hole of the cover member attached to the cylinder forming portion from the outside, and the guide forming member is fixed to the cover member at the flange portion, so that a portion of the guide forming member on the tip end side of the cover portion of the rod-shaped portion extends in the longitudinal direction of the cylinder in the cylinder. Therefore, the rod-shaped portion serves as a guide portion extending in the cylinder.

(5) With regard to the structure for reciprocating the plunger, in the above embodiment, the forward movement and the return movement of the plunger 18 are performed by applying the pressure of the compressed air to the pressure receiving surface 18a on the one side and the pressure receiving surface 18b on the other side of the plunger 18. However, in the present invention, the reciprocating movement of the plunger is not limited to this, and a spring member may be provided between the one pressure receiving surface and the bottom surface of the cylinder hole or between the other pressure receiving surface and the inner end surface of the cylinder in the cylinder, and one of the forward movement and the return movement may be performed by the urging force of the spring member.

(6) The above-described embodiment is an example in which the present invention is applied to a weft cutting device 10, and the weft cutting device 10 is attached to a tuck-in head 5 that is driven to reciprocate in the front-rear direction of a loom 1 and swings together with the tuck-in head 5. However, the weft cutting device to which the present invention is applied is not limited to this type of weft cutting device, and may be, for example, a weft cutting device fixedly arranged on a loom so as to be attached to a normal tuck-in head fixedly arranged on the loom. The present invention can be adapted to the yarn feeding scissors and the waste selvedge scissors which are similarly fixed to the loom.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.