EASING ROLLER RETRACTING DEVICE FOR LOOM

Abstract

 Provided is an easing roller retracting device for a loom, the loom including an easing roller (1) and an easing mechanism (E1, E2, E3, E4). The easing roller (1) is swingably supported by a loom frame (F) and warp yarns (T) let off from a warp beam (WB) are looped over the easing roller (1). A position of the easing roller (1) during weaving is set so that at least a part of the easing roller (1) is located below an upper end of the warp beam (WB) in a vertical direction. The easing mechanism (E1, E2, E3, E4) is connected to the easing roller (1) and swings the easing roller (1) to absorb variation of a tension of the warp yarns (T) in each loom cycle for weaving. The easing roller retracting device allows an operation of shifting (lifting) an easing roller (1) to a retracted position at which the easing roller (1) does not interfere with a warp beam (WB) when attaching or detaching the warp beam (WB) to be easily performed without making the structure of the loom complex,
The easing mechanism (E1, E2, E3, E4) is capable of swinging and displacing the easing roller (1) to a retracted position that is beyond a swing range of the easing roller (1) during weaving and at which a lower end of the easing roller (1) is located above the upper end of the warp beam (WB).

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention relates to an easing roller retracting device for a loom, the loom including an easing roller and an easing mechanism. The easing roller is swingably supported by a loom frame and warp yarns let off from a warp beam are looped over the easing roller. A position of the easing roller during weaving is set so that at least a part of the easing roller is located below an upper end of the warp beam (to be more specific, an upper end of a flange portion of the warp beam) in a vertical direction. The easing mechanism is connected to the easing roller and swings the easing roller to absorb variation of a tension of the warp yarns in each loom cycle for weaving.

2. Description of the Related Art

[0002] For example, Japanese Unexamined Patent Application Publication No. 2004-250817 describes a loom including an easing mechanism described above. In the loom disclosed in Japanese Unexamined Patent Application Publication No. 2004-250817, warp yarns let off from a warp beam are looped over a first roller, which serves as a guide roller. Further, the warp yarns are looped over a second roller, which serves as an easing roller, so that the direction of the warp yarns is changed, and the warp yarns are guided toward the cloth fell. The guide roller (first roller) is provided so that the angle at which the warp yarns are looped over the easing roller (second roller) would not change even when the diameter of the warp yarns wound around the warp beam changes. Usually, the guide roller is disposed at a position upstream from the easing roller along the path of the warp yarns and below the easing roller.

[0003] In the loom disclosed in Japanese Unexamined Patent Application Publication No. 2004-250817, the easing roller (second roller) is swingably supported by loom frames by means of easing levers. To be specific, each of the easing levers is rotatably supported at one end thereof via a support shaft by a corresponding one of the loom frames at left and right parts of the loom. The easing roller is supported at both ends thereof by middle portions of the easing levers. Accordingly, the easing roller is supported by the loom frames so as to be swingable around the axes of the support shafts, which support the easing levers.

[0004] Moreover, an easing mechanism is connected to the other end of each of the easing levers. The easing mechanism includes an easing rod, which is connected to the easing lever, and an eccentric driving mechanism (crank-type driving device), which is connected to the easing rod. Synchronously with rotation of the loom (the main shaft), the eccentric driving mechanism is rotated once while the main shaft rotates once. The easing mechanism of the loom described in Japanese Unexamined Patent Application Publication No. 2004-250817 is a so-called active easing mechanism. With the active easing mechanism, as the eccentric driving mechanism rotates, the easing rods are reciprocated in the front-back direction (the extension direction of the warp yarns from the easing roller to the cloth fell), and thereby the easing levers are rotated back and forth around the support shafts. Thus, the easing roller performs an easing motion in which the easing roller swings back and forth around the axes of the support shafts. The easing motion is performed in order to reduce (absorb) variation of the tension of the warp yarns due to a shedding motion and the like in each loom cycle (corresponding to a period from beating to the next beating in a series of weaving operations performed by the loom and corresponding to a range of 0° to 360° of the rotation angle of the main shaft).

[0005] Regarding a loom, in order to facilitate maintenance when warp yarn breakage occurs and in order to improve easy operation of the loom, it is desirable that the height of a warp line during weaving (corresponding to the height position of warp yarns from the easing roller to the cloth fell) be set low. In order to set the height of the warp line to be low, it is necessary to make the height position of the easing roller, which form the warp line, be low. However, regarding a loom, it is necessary to perform an operation of replacing a warp beam when warp yarns wound around a warp beam have been exhausted or when making a style change. In the replacement operation, a warp beam is removed and attached by rolling the warp beam on beam guides disposed on loom frames. If the height position of the easing roller were low, the warp beam would interfere with the easing roller when the warp beam is removed and attached. Therefore, there is no other choice but to make the height position of the easing roller to be a high position at which the easing roller would not interfere with the warp beam.

[0006] Japanese Unexamined Patent Application Publication No. 09-111600 describes a guide roller lifting device that shifts (lifts) a guide roller (in this Publication, a back roller), which is located below an easing roller, to a retracted position when replacing a warp beam. In a similar way, it may be possible to set the height position of an easing roller during weaving at a position at which the aforementioned interference occurs, that is, a position at which at least a part of the easing roller is located below an upper end of a warp beam in the vertical direction, and, when replacing the warp beam, to shift the easing roller to a retracted position at which the easing roller does not interfere with the warp beam. However, an easing roller differs from the guide roller described in Japanese Unexamined Patent Application Publication No. 09-111600 in that it is difficult to easily perform an operation of shifting the easing roller to the retracted position, because easing mechanisms, such as those described in Japanese Unexamined Patent Application Publication No. 2004-250817, are connected the easing roller.

[0007] For example, in the case of the loom disclosed in Japanese Unexamined Patent Application Publication No. 2004-250817, in order to shift the easing roller to a retracted position, first, it is necessary to disconnect the easing levers from the easing rods or disconnect the easing rods from the eccentric driving mechanisms to disconnect link mechanisms, which are included in the easing mechanisms, from the loom frames. Naturally, after attaching a warp beam, it is necessary to perform operations, such as reconnection and adjustment of the disconnected components. Moreover, when the components are disconnected from each other as described above, a part of the link mechanisms, which are connected to the easing roller, becomes suddenly displaced due to the weight of the easing roller and the like. Therefore, in order to avoid danger, it is necessary to perform an operation of disconnecting the easing levers and the like while holding them, and such an operation takes an effort and is cumbersome.

[0008] Furthermore, in the case of the easing roller, the easing roller is shifted to the retracted position in a state in which at least a part of the link mechanisms is connected to the easing roller. Considering that the easing roller alone is heavy, it takes a great effort to perform such an operation. It may be possible to provide the loom with a dedicated easing roller lifting mechanism that is similar to the guide roller lifting device described in Japanese Unexamined Patent Application Publication No. 09-111600. However, in this case, a mechanism surrounding a let-off device of the loom becomes complex and the cost of the entirety of the loom is increased. Moreover, even if the easing roller were enabled to be lifted mechanically, it would be necessary to disconnect the link mechanisms, which are included in the easing mechanisms, from the loom frames as described above. Therefore, such a cumbersome operation is unavoidable.

SUMMARY OF THE INVENTION

[0009] In consideration of the problems of existing technologies described above, an object of the present invention is to provide an easing roller retracting device for the loom described above in "Field of the Invention", which can, without making the structure of the loom complex, easily perform an operation of shifting (lifting) the easing roller to a retracted position at which the easing roller does not interfere with the warp beam when an operation of attaching and removing the warp beam is performed.

[0010] In order to achieve the object, according to the present invention, in the loom described above, the easing mechanism that is capable of swinging and displacing the easing roller to a retracted position that is beyond a swing range of the easing roller during weaving and at which a lower end of the easing roller is located above the upper end of the warp beam in the vertical direction.

[0011] The easing mechanism according to the present invention may be an active easing mechanism including a link mechanism connected to the easing roller, a driving shaft that rotates synchronously with a main shaft of the loom, a driving member rotated by the driving shaft, and an eccentric shaft supported by the driving member at a position at which an axis thereof is eccentric to an axis of a support shaft that supports the driving member. The eccentric shaft imparts a reciprocating motion in a front-back direction to the link mechanism by being connected to a connection portion that is provided at one end portion of an easing rod that is included in the link mechanism, the one end portion being farther from the easing roller. The active easing mechanism is capable of setting an eccentricity of the axis of the eccentric shaft with respect to the axis of the support shaft at a first eccentricity and a second eccentricity, the first eccentricity being an eccentricity during weaving, the second eccentricity being an eccentricity for shifting the easing roller to the retracted position.

[0012] The active easing mechanism may be a crank-type active easing mechanism in which the driving member is supported by the driving shaft and the driving shaft functions as the support shaft. The crank-type active easing mechanism includes a rotation shaft that is supported by the driving member and that is disposed at a position at which an axis thereof is eccentric to the axis of the driving shaft, a transmission member that is disposed so as to surround the rotation shaft and that is supported by the rotation shaft via a bearing so as to be rotatable relative to the rotation shaft, and an engagement member that prohibits relative rotation of the rotation shaft and the transmission member. The easing rod is rotatably connected to the transmission member via a connection shaft that is fitted into the one end portion, and the easing rod is securely engageable with the transmission member at a middle portion thereof.

[0013] In the crank-type active easing mechanism, during weaving, the easing rod is securely engaged with the transmission member at the middle portion so that rotation of the easing rod relative to the transmission member around the connection shaft is prohibited and the transmission member and the easing rod are allowed to move together, the transmission member functions as the connection portion, the rotation shaft functions as the eccentric shaft, and an eccentricity of the axis of the rotation shaft with respect to the axis of the driving shaft becomes the first eccentricity. When the easing roller is retracted, the secure engagement of the easing rod with the transmission member is released so that the easing rod is rotatable relative to the transmission member around the connection shaft and relative rotation of the transmission member and the rotation shaft is prohibited by the engagement member, a part of the easing rod into which the connection shaft is fitted functions as the connection portion, the connection shaft functions as the eccentric shaft, and the eccentricity of the axis of the connection shaft with respect to the axis of the driving shaft becomes the second eccentricity.

[0014] With the present invention, in order to absorb variation of the tension of warp yarns in each loom cycle during weaving, an easing mechanism is used that imparts an easing motion due to a back-and-forth swinging motion to an easing roller, which is swingably supported by a loom frame. The easing mechanism is capable of swinging and displacing the easing roller to a retracted position that is beyond a swing range of the easing roller during weaving and at which a lower end of the easing roller is located above the upper end of the warp beam. Therefore, the easing roller can be shifted to the retracted position without using a dedicated lifting device. Moreover, because the operation of shifting the easing roller to the retracted position is performed by swinging the easing roller by using the easing mechanism, it is not necessary to disconnect the link mechanism of the easing mechanism from the loom frame, so that the operation is facilitated.

[0015] The easing mechanism may be an active easing mechanism that imparts a swinging motion due to rotation of the driving shaft to the easing roller via a driving member rotated by the driving shaft, an eccentric shaft supported by the driving member, and a link mechanism connected to the eccentric shaft and to the easing roller. In this case, the easing roller is not shifted (lifted) to the retracted position manually but mechanically, so that the operation of shifting the easing roller to the retracted position is further facilitated.

[0016] The active easing mechanism may be capable of setting an eccentricity of the axis of the eccentric shaft with respect to the axis of the support shaft at a first eccentricity and a second eccentricity, the first eccentricity being an eccentricity during weaving, the second eccentricity being an eccentricity for moving the easing roller to the retracted position. In this case, when shifting the easing roller to the retracted position, it is only necessary to change the setting of the eccentricity of the easing mechanism from the first eccentricity to the second eccentricity, so that the operation of shifting the easing roller to the retracted position is further facilitated.

[0017] The active easing mechanism may be capable of switching between a member (rotation shaft) that has the first eccentricity with respect to the axis of the driving shaft, which is used during weaving, and a member (connection shaft) that has the second eccentricity with respect to the axis of the driving shaft, which is used when retracting the easing roller. In this case, the eccentricity can be changed (switched) by using a more compact device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 

Fig. 1 is a side view illustrating a loom including an easing roller retracting device according to a first embodiment of the present invention in a state during weaving;

Fig. 2 is a plan view illustrating an example of a loom including an easing roller retracting device according to the present invention;

Fig. 3 is a schematic perspective view illustrating an example of an easing roller retracting device according to the present invention;

Fig. 4A is a side view and Fig. 4B is a partial sectional plan view illustrating a main part of an easing mechanism of the easing roller retracting device according to the first embodiment of the present invention;

Fig. 5A is a side view and Fig. 5B is a partial sectional view illustrating the details of a part of the easing mechanism of the easing roller retracting device according to the first embodiment of the present invention;

Fig. 6 is a side view illustrating the loom including the easing roller retracting device according to the first embodiment of the present invention in a state in which the easing roller is retracted;

Figs. 7A and 7B are motion diagrams of a main part of the easing mechanism of the easing roller retracting device according to the first embodiment of the present invention;

Fig. 8A is a side view illustrating an easing roller retracting device according to another embodiment of the present invention, and Figs. 8B and 8C are enlarged views illustrating a main part of the easing roller retracting device;

Figs. 9A and 9B are motion diagrams of the other embodiment illustrated in Figs. 8A and 8B, respectively illustrating a state during weaving and a state in which the easing roller is retracted;

Fig. 10A is a side motion diagram of an easing roller retracting device according to still another embodiment of the present invention, and Fig. 10B is an enlarged view of a main part of the easing roller retracting device, each illustrating a state during weaving;

Fig. 11A is a side motion diagram of the easing roller retracting device according to the still another embodiment illustrated in Figs. 10A and 10B, and Fig. 11B is an enlarged view of a main part of the easing roller retracting device, each illustrating a state in which the easing roller is retracted; and

Fig. 12 is a side view illustrating an easing roller retracting device according to still another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Referring to Figs. 1 to 7B, an easing roller retracting device according to an embodiment of the present invention will be described. The embodiment described below is an example in which a crank-type active easing mechanism is used as an easing mechanism of the present invention.

[0020] Figs. 1 to 3 illustrate a loom to which the present invention is applied. The loom includes a pair of left and right loom frames F, an easing roller 1, and a guide roller GR. The loom frames F are disposed so as to be separated from each other in the weaving-width direction. Each of the loom frames F includes a frame body Fb and a support bracket Fa. The support bracket Fa is disposed on an upper surface of a part of the frame body Fb located on the let-off side. The easing roller 1 and the guide roller GR are each supported at shaft portions at both ends thereof by the loom frames F via the support brackets Fa. In the loom according to the present embodiment, the loom frames F on the left and right sides have the same structure. Therefore, basically only the structure on one side will be described below in detail. In the following description, regarding each member, the term "inside" refers to a side nearer to the center of the loom in the weaving-width direction and the term "outside" refers to the opposite side. The term "front-back direction" refers to an extension direction in which warp yarns T extend from the easing roller 1 to the cloth fell (not shown). The term "front side (forward)" refers to the easing roller 1 side in the front-back direction (the let-off side of the warp yarns T), and the term "back side (backward)" refers to a side opposite from the easing roller 1 side (a side farther from the easing roller/cloth fell side).

[0021] A first support shaft 7 is disposed on the support bracket Fa of the loom frame F so as to protrude inward from an inner end surface of the support bracket Fa in the weaving-width direction. A tension detection lever 3 is rotatably supported by the first support shaft 7 via a bearing. In other words, the tension detection lever 3 is rotatably supported by the loom frame F via the first support shaft 7.

[0022] In the example shown in the figures, the tension detection lever 3 includes a support portion 3a and two arm portions 3b and 3c. The support portion 3a is cylindrical and supported by the first support shaft 7. The two arm portions 3b and 3c are integrally formed so as to protrude from the outer peripheral surface of the support portion 3a. The two arm portions 3b and 3c are disposed with the axis of the support portion 3a (the first support shaft 7) therebetween and extend perpendicularly to the axis. A load cell 5 is connected to an end portion of the arm portion 3b, which is one of the two arm portions 3b and 3c that extends downward. The load cell 5 includes a load cell body 5a, which is S-shaped, and connection rods 5b. The connection rods 5b are attached to both sides of the load cell body 5a facing in directions from which the load cell body 5a receives load. The load cell 5 is connected to the arm portion 3b of the tension detection lever 3 at one of the connection rods 5b via a spherical bearing, and the load cell 5 is supported by the support bracket Fa at the other connection rod 5b via a spherical bearing. Accordingly, the tension detection lever 3, which is rotatably supported by the loom frame F, is connected to the loom frame F at the arm portion 3b thereof via the load cell 5. The phase of the tension detection lever 3 around the axis of the first support shaft 7 is fixed (maintained) by the load cell 5.

[0023] In the example shown in the figures, the arm portion 3c, which is one of the two arm portions 3b and 3c of the tension detection lever 3 that extends upward, has a cylindrical end portion in which a through-hole is formed. A second support shaft 9 is fitted into the arm portion 3c via a bearing, such as a needle bearing, fitted into the through-hole. In other words, the second support shaft 9 is rotatably supported by the tension detection lever 3 at the arm portion 3c. As described above, the phase of the tension detection lever 3 around the axis of the first support shaft 7 is fixed (maintained) by the load cell 5. Accordingly, the position of the second support shaft 9 is fixed around the axis of the first support shaft 7.

[0024] The second support shaft 9 is supported by the tension detection lever 3 at an inner end portion thereof and extends from the support position outward in the weaving-width direction. A tension lever 11 is fixed the second support shaft 9 at a position that is outside from the support position, at which the second support shaft 9 is supported by the tension detection lever 3, and that is between the tension detection lever 3 and the support bracket Fa.

[0025] The tension lever 11 has through-holes at both end portions thereof. One of the end portions has a slit extending from an end edge to the through-hole and has a split clamp structure with which the diameter of the through-hole can be reduced by fastening a bolt 11a. The tension lever 11 is fixed to and supported by the second support shaft 9 at the end portion having the split clamp structure so as to form a predetermined angle (in the example shown in the figures, substantially 90°) with the arm portion 3c of the tension detection lever 3.

[0026] One of shaft portions 1a of the easing roller 1 is fitted into the other end portion of the tension lever 11 via a bearing that is fitted into the through-hole in the other end portion. Accordingly, the shaft portions 1a at both ends of the easing roller 1 are each supported by the second support shaft 9 via the tension lever 11. The phases of the tension detection levers 3, which are respectively provided on the pair of left and right loom frames F, around the axes of the first support shafts 7 are fixed by the load cells 5 so that the positions of the through-holes in the arm portions 3c of the tension detection levers 3 substantially coincide with each other in a side view. Accordingly, the positions of the axes of the second support shafts 9, which are respectively provided on the loom frames F, also coincide with each other in a side view. Moreover, the tension levers 11 are fixed to the second support shafts 9 so that the tension detection levers 3 and the tension levers 11 form the same angle with the respective loom frames F on respective sides. Thus, the easing roller 1 is supported by the tension levers 11 in a state in which the easing roller 1 extends parallel to the first support shafts 7 and the second support shafts 9.

[0027] A large number of warp yarns T, which have been let off from the warp beam WB in a sheet-like shape and guided by the guide roller GR, are looped over the easing roller 1. Accordingly, with the structure described above, the load acting on the easing roller 1 due to the tension of the warp yarns T is applied to the load cell 5 through the tension lever 11, the second support shaft 9, and the tension detection lever 3. The load cell 5 detects the load, thereby measuring the tension of the warp yarns T. Thus, in the present embodiment, the easing roller 1 not only functions as a part of an easing device that absorbs variation of the tension of the warp yarns T in each loom cycle during weaving but also functions as a tension detection roller of a tension detection device for detecting the tension of the warp yarns T.

[0028] In the present embodiment, the second support shaft 9, which supports the easing roller 1, extends outward from the support position, at which the second support shaft 9 is supported by the tension detection lever 3, to the outside of the loom frame F. An easing mechanism, which imparts a swinging motion (easing motion) in the front-back direction to the easing roller 1, is connected to the outer end portion of the second support shaft 9. In the present embodiment, the second support shaft 9 is supported not only by the tension detection lever 3 but also by the support bracket Fa of the loom frame F at a position outside from the tension lever 11. To be specific, a through-hole is formed in the support bracket Fa of the loom frame F at a position at which the central axis of the through-hole substantially coincides with the central axis of a through-hole 3c1 formed in the arm portion 3c of the tension detection lever 3, and the second support shaft 9 is supported by the support bracket Fa via a bearing fitted into the through-hole. In other words, the second support shaft 9 is rotatably supported by the tension detection lever 3 at an end portion thereof protruding inward from the loom frame F (the support bracket Fa), and the second support shaft 9 is also rotatably supported by the loom frame F (the support bracket Fa).

[0029] In the present embodiment, an easing mechanism E1, which is a crank-type active easing mechanism, includes an eccentric driving mechanism 20 as a driving device and a link mechanism 30 that transmits motion of the eccentric driving mechanism 20 to the second support shaft 9. As illustrated in Fig. 1 and other figures, the link mechanism 30 includes an easing rod 31, which is connected to the eccentric driving mechanism 20, and an easing lever 32, which connects the second support shaft 9 and the easing rod 31 to each other.

[0030] The easing lever 32 of the link mechanism 30 has split clamp structures at both end portions thereof. The easing lever 32 is fixed to the second support shaft 9 at one of the end portions by using one of the split clamp structures. The easing lever 32 extends downward from the position at which the easing lever 32 is connected to the second support shaft 9. A connection shaft 32a is fixed to the other end portion of the easing lever 32 by using the other split clamp structure. The easing rod 31 includes a conrod 31a and a connection member 31b. The conrod 31a is connected to the eccentric driving mechanism 20 at one end portion thereof on the back side (hereinafter, referred to as "back end portion"). The connection member 31b is attached to the other end portion of the conrod 31a on the front side. A spherical bearing (not shown) is fitted into a through-hole formed at an end portion of the connection member 31b on the front side.

[0031] The easing lever 32 and the easing rod 31 are connected to each other so as to be rotatable relative to each other by fitting and fixing the connection shaft 32a, which has been fixed to the other end portion of the easing lever 32, to an inner race of the spherical bearing fitted into the connection member 31b of the easing rod 31. Therefore, with the link mechanism 30, the easing rod 31 is reciprocated in the front-back direction by the eccentric driving mechanism 20, and thereby the easing lever 32 is swung back and forth around the axis of the second support shaft 9. As a result, the second support shaft 9 is rotated back and forth in a range corresponding to the swing amount of the easing lever 32. Accordingly, the easing roller 1, which is supported by the second support shaft 9 via the tension lever 11, performs a swinging motion (easing motion) around the axis of the second support shaft 9.

[0032] The eccentric driving mechanism 20 basically has the same structure as a crank-type driving device disclosed in Japanese Unexamined Patent Application Publication No. 2008-180289, which is a related-art document. As illustrated in detail in Figs. 4A to 5B, the eccentric driving mechanism 20 includes a crank hub 21 as a driving member, a holder 22 fixed to the crank hub 21, and a transmission member 23 supported by the holder 22 so as to be rotatable relative to the holder 22. Figs. 5A and 5B are partial views illustrating only the crank hub 21, the holder 22, and a driving shaft 13 of the structure shown in Figs. 4A and 4B. Hereinafter, the structure of the eccentric driving mechanism 20 will be described in more detail. The eccentric driving mechanism 20 is supported by the driving shaft 13, which protrudes outward from a side surface of the loom frame F. Therefore, in the following description, the term "outside" refers a side of each member nearer to a distal end portion of the driving shaft 13 (a side farther from the loom frame F) and the term "inside" refers to the loom frame F side.

[0033] The crank hub 21 is fixed to the distal end portion of the driving shaft 13, which protrudes outward from the loom frame F. In other words, in the present embodiment, the crank hub 21, which is a driving member, is supported by the driving shaft 13, and the driving shaft 13 and a support shaft are the common shaft. The driving shaft 13 is rotatably supported by the frame body Fb of the loom frame F and is connected to the main shaft of the loom (not shown). Synchronously with the rotation of the main shaft of the loom, the driving shaft 13 rotates once when the main shaft rotates once.

[0034] The crank hub 21 includes a shaft portion 21a and a flange portion 21b. A through-hole 21d having substantially the same diameter as the driving shaft 13 is formed in the shaft portion 21a. The flange portion 21b is integrally formed with the shaft portion 21a. The shaft portion 21a of the crank hub 21 has a split clamp structure in which a slit connected to the through-hole 21d is formed. In a state in which the driving shaft 13 is fitted into the through-hole 21d, the crank hub 21 is fixed to the driving shaft 13 by using the split clamp structure of the shaft portion 21a.

[0035] The holder 22 includes an attachment portion 22a and a shaft portion 22b. The attachment portion 22a has a flat plate-like shape and is fixed to the flange portion 21b of the crank hub 21. The shaft portion 22b, which serves as a rotation shaft, is integrally formed with the attachment portion 22a so as to protrude from an inner end surface of the attachment portion 22a. A through-hole 22c is formed in the shaft portion 22b. The through-hole 22c extends through the shaft portion 22b and has an opening in an outer end surface of the attachment portion 22a.

[0036] The holder 22 is attached to the crank hub 21 by screwing a plurality of (in the example shown in the figures, three) screw members from the crank hub 21 side in a state in which the driving shaft 13 is disposed so as to extend through the through-hole 22c and an outer end surface of the attachment portion 22a is in contact with an inner end surface of the flange portion 21b of the crank hub 21. Accordingly, the shaft portion 22b of the holder 22 is supported by the crank hub 21, which serves as a driving member, via the attachment portion 22a, because the holder 22 is attached to the crank hub 21, which is fixed to the driving shaft 13.

[0037] The holder 22 is attached to the crank hub 21 so that an axis 22b1 of the shaft portion 22b is disposed eccentric to an axis 13a of the driving shaft 13. Therefore, in the structure shown in the figures, in order to allow the shaft portion 22b to be eccentric to the driving shaft 13, the through-hole 22c, through which the driving shaft 13 extends, has a size larger than the diameter of the driving shaft 13 at least in the direction of eccentricity.

[0038] Regarding the direction of eccentricity, in the structure shown in the figures, as illustrated in detail in Figs. 5A and 5B, the holder 22 includes a pair of restriction portions 22d, which are used for positioning. The restriction portions 22d are disposed so that the driving shaft 13 is located therebetween in a state in which the driving shaft 13 is inserted through the through-hole 22c. The restriction portions 22d protrude from the outer end surface of the attachment portion 22a of the holder 22. Each of the restriction portions 22d includes a restriction surface 22d1 on a linearly extending plane. The restriction surfaces 22d1 of the restriction portions 22d face each other and extend parallel to each other.

[0039] The crank hub 21 includes a guide portion 21c, which is cylindrical and protrudes from the inner end surface of the flange portion 21b. A guide groove 22e, into which the guide portion 21c of the crank hub 21 is fitted, is formed in the holder 22, which is attached to the crank hub 21. The width direction of the guide groove 22e of the holder 22 coincides with the extension direction of the restriction surfaces 22d1 of the restriction portions 22d. The dimension of the guide groove 22e in the width direction is substantially the same as the diameter of the guide portion 21c of the crank hub 21. The dimension of the guide groove 22e in the longitudinal direction (the direction perpendicular to the width direction) is larger than the diameter of the guide portion 21c.

[0040] Thus, the holder 22 is displaceable in the longitudinal direction of the guide groove 22e relative to the crank hub 21, which is fixed to the driving shaft 13, in a state in which the guide portion 21c is fitted into the guide groove 22e and the holder 22 is attached to the crank hub 21 but is not fixed to the crank hub 21 by using the screw members. Positioning of the holder 22 relative to the crank hub 21 is performed by bringing one of the restriction surfaces 22d1 of the restriction portion 22d of the holder 22 into contact with a corresponding one of a pair of end surfaces 21e, which are formed in side surfaces of the crank hub 21 and which extend parallel to each other. Holes formed in the crank hub 21, into which the screw members are inserted, are elongated holes that are elongated in a direction perpendicular to the end surfaces 21e so that the crank hub 21 and the holder 22 can be fixed to each other in a state in which the holder 22 is in contact with whichever of the pair of the end surfaces 21e of the crank hub 21.

[0041] Regarding the crank hub 21 and the holder 22, the dimension from the through-hole 21d to each of the end surfaces 21e of the crank hub 21 and the dimension from the axis 22b1 of the shaft portion 22b to each of the restriction surfaces 22d1 of the holder 22 are set so that the axis 22b1 of the shaft portion 22b of the holder 22 is eccentric to the axis 13a of the driving shaft 13 in a state in which the end surface 21e of the crank hub 21 and the restriction surface 22d1 of the restriction portion 22d of the holder 22 are in contact with each other.

[0042] Accordingly, in the state in which the holder 22 is positioned relative to the crank hub 21, the axis 22b1 of the shaft portion 22b of the holder 22 is eccentric to the axis 13a of the driving shaft 13 in the longitudinal direction of the guide groove 22e of the holder 22. Therefore, the longitudinal direction of the guide groove 22e, that is, the direction perpendicular to the restriction surfaces 22d1 of the restriction portion 22d of the holder 22, is the direction of eccentricity. In the structure illustrated in Figs. 4A to 5B, in either of a state in which the restriction portion 22d on the left side of Fig. 5B is in contact with one of the end surfaces 21e of the holder 22 (as shown in the figures) and a state in which the restriction portion 22d on the right side of Fig. 5B is in contact with the other end surface 21e of the holder 22, the axis 22b1 of the shaft portion 22b of the holder 22 is eccentric to the axis 13a of the driving shaft 13 in a direction the same as the aforementioned direction of eccentricity, which is the direction to the right side in the figures. However, the eccentricities of the axis 22b1 of the shaft portion 22b with respect to the axis 13a of the driving shaft 13 in the two states differ from each other. In other words, the eccentric driving mechanism 20 according to the present embodiment is capable of setting two different eccentricities, each for imparting an easing motion to the easing roller 1.

[0043] The transmission member 23 is supported by the shaft portion 22b, which is the rotation shaft of the holder 22, via a bearing 24. To be specific, the transmission member 23 includes a base portion 23a, which is substantially disc-shaped, as a main part thereof. A through-hole 23b, which has a diameter larger than that of the shaft portion 22b of the holder 22, is formed in the base portion 23a. An inner race of the bearing 24 is fixed to the shaft portion 22b of the holder 22, and the outer race of the bearing 24 is fitted and fixed to the through-hole 23b. Thus, the transmission member 23 is supported by the holder 22 so as to be rotatable relative to the holder 22 in such a way that the inner peripheral surface of the through-hole 23b surrounds the shaft portion 22b of the holder 22.

[0044] The transmission member 23 includes first and second joint portions 23c and 23d for connecting the easing rod 31. The first joint portion 23c and the second joint portion 23d are disposed with the through-hole 23b therebetween and so as to protrude from the side surfaces of the base portion 23a. The back end portion of the conrod 31a of the easing rod 31 is connected to the first joint portion 23c by using a connection pin 25, which serves as a connection shaft.

[0045] To be specific, a through-hole 23c1, into which the connection pin 25 is fitted, is formed in the first joint portion 23c of the transmission member 23. An insertion hole 31c1, into which the connection pin 25 is fitted, is formed at the back end portion of the conrod 31a of the easing rod 31. The connection pin 25 has a head portion having a large diameter for preventing the connection pin 25 from being pulled out. The transmission member 23 and the conrod 31a are attached to each other by fitting the connection pin 25, which has been inserted into the through-hole 23c1 of the transmission member 23 from the inside, into the insertion hole 31c1 of the conrod 31a. The transmission member 23 and the conrod 31a are connected to each other by fixing the connection pin 25 to the conrod 31a by screwing a set screw (not shown) from the side surface of the back end portion of the conrod 31a in a state in which the head portion of the connection pin 25 is in contact with the first joint portion 23c of the transmission member 23. The connection pin 25 is only fitted into the transmission member 23 and prevented from being pulled out by using the head portion, so that the connection pin 25 and the transmission member 23 can rotate relative to each other. Accordingly, the conrod 31a (easing rod 31) is rotatably connected to the transmission member 23 via the connection pin 25, which is fixed to the conrod 31a.

[0046] When imparting an easing motion to the easing roller 1 during weaving, the conrod 31a of the easing rod 31, which is connected to the first joint portion 23c of the transmission member 23, is connected to the transmission member 23 in such a way that the conrod 31a extends from the first joint portion 23c to the second joint portion 23d of the transmission member 23. Therefore, as illustrated in the figures, the conrod 31a has a shape that is bent in a trapezoidal shape in a region in which the transmission member 23 is present so as to circumvent the driving shaft 13, the crank hub 21, and the like, which protrude from the through-hole 23b of the transmission member 23. Moreover, the conrod 31a has such a shape that the conrod 31a is in contact with an outer end surface (contact surface) of the second joint portion 23d of the transmission member 23 and the conrod 31a extends from the contact position in the direction perpendicular to the axis of the driving shaft 13.

[0047] The conrod 31a includes a secure engagement portion 31a1, which is located at the contact position at which the conrod 31a is in contact with the second joint portion 23d of the transmission member 23. The secure engagement portion 31a1 has a dimension in the width direction (the direction perpendicular to the extension direction) that is larger than those of other portions. Through-holes are formed in both side portions of the secure engagement portion 31a1 with the center of the secure engagement portion 31a1 therebetween in the width direction. Two female screw holes are formed in the second joint portion 23d of the transmission member 23 so as to correspond to the secure engagement portion 31a1 of the conrod 31a. The conrod 31a is fixed to the transmission member 23 at the contact position by screwing screw members 26, which have been inserted into the through-holes of the secure engagement portion 31a1 of the conrod 31a from the outside, into the female screw holes formed in the second joint portion 23d of the transmission member 23. Accordingly, the conrod 31a, which is rotatably connected to the first joint portion 23c of the transmission member 23 via the connection pin 25 (connection shaft) at the back end portion thereof,
is, during weaving, fixed to (securely engaged with) the second joint portion 23d of the transmission member 23 at a position at which the conrod 31a is in contact with the second joint portion 23d, so that the conrod 31a is integrated with the transmission member 23 in a state in which rotation of the conrod 31a around the connection pin 25 is prohibited.

[0048] With the structure of the easing mechanism E1 described above, when the crank hub 21, which serves as a driving member, rotates as the driving shaft 13 rotates, the shaft portion 22b of the holder 22, which is supported by the crank hub 21, performs an eccentric rotational motion with respect to the driving shaft 13 in such a way that the axis 22b1 of the shaft portion 22b rotates along a circle that is centered at the axis 13a of the driving shaft 13 and that has a radius equal to the eccentricity of the axis 22b1. Accordingly, the transmission member 23, which is supported by the shaft portion 22b of the holder 22 via the bearing 24, and the conrod 31a of the easing rod 31, which is fixed to the transmission member 23, perform a non-rotational eccentric motion centered at the axis 13a of the driving shaft 13. Due to displacement in the front-back direction caused by the eccentric motion, the easing rod 31 is reciprocated in the front-back direction. As a result, the easing lever 32, which is connected to the easing rod 31, performs a back-and-forth swinging motion around the axis of the second support shaft 9, the back-and-forth swinging motion causes the second support shaft 9 to perform a reciprocating motion, and thereby the easing roller 1 performs an easing motion.

[0049] In the structure according to the present embodiment, in a state in which the direction of eccentricity of the eccentric driving mechanism 20 coincides with the extension direction of the easing rod 31, the easing lever 32 is located at the swinging limit of the back-and-forth swinging motion (the dead center of the easing mechanism E1). The easing lever 32 is swung back and forth with a swing amount corresponding to the eccentricity of the eccentric driving mechanism 20, and the swing amount of the easing motion of the easing roller 1 corresponds to the swing amount of the easing lever 32. Typically, an easing motion of the easing roller 1 for reducing variation of the tension of the warp yarns T in each loom cycle during weaving is a swinging motion with an angular range of 2 to 3° and less than 10° at the maximum. Accordingly, eccentric driving mechanisms of existing easing mechanisms are capable of setting the eccentricity with which an easing motion of such an angular range can be realized.

[0050] As described above, the eccentric driving mechanism 20 according to the present embodiment is capable of setting two types of eccentricity. During weaving, either of the two types of eccentricity is set, and the easing roller 1 is driven. Accordingly, the two types of eccentricity, which can be selectively set, both correspond to a first eccentricity in the present invention. With the structure according to the present embodiment, in the state illustrated in Figs. 4A, 4B, and other figures, which is a state during weaving, the shaft portion 22b of the holder 22, which serves as a rotation shaft, performs an eccentric rotational motion with respect to the driving shaft 13, and thereby the easing rod 31 is reciprocated in the front-back direction. In this state, the shaft portion 22b of the holder 22 corresponds to an eccentric shaft in the present invention. Moreover, in the state illustrated in Figs. 4A, 4B, and other figures, the conrod 31a of the easing rod 31 is integrated with the transmission member 23 and is connected to the shaft portion 22b of the holder 22, which corresponds to an eccentric shaft, via the transmission member 23. Accordingly, in this state, the transmission member 23 functions as a part of the easing rod 31, and the transmission member 23 corresponds to a connection portion in the present invention.

[0051] With the structure according to the present invention, the eccentric driving mechanism 20 of the easing mechanism E1 described above is capable of switching the eccentric shaft, which is disposed so as to be eccentric to the axis 13a of the driving shaft 13 and which imparts a motion corresponding to the eccentricity thereof, between an eccentric shaft used during weaving and an eccentric shaft used when retracting the easing roller 1. To be specific, the eccentric driving mechanism 20 is structured as follows.

[0052] As described above, the easing rod 31 of the link mechanism 30 is securely engaged with (fixed to) the transmission member 23 by using the screw members 26 at the secure engagement portion 31a1 of the conrod 31a, which is located at the middle portion of the easing rod 31. In other words, the easing rod 31 can be made to be rotatable relative to the transmission member 23 around the connection pin 25 by releasing the secure engagement of the easing rod 31 (conrod 31a) by removing the screw members 26.

[0053] In the eccentric driving mechanism 20, two female screw holes 23e, which have openings in an outer end surface of the base portion 23a and into which the screw members 26 can be screwed, are formed in the base portion 23a of the transmission member 23. The female screw holes 23e are located at positions between which the through-hole 21d is interposed and that are different from those of the first and second joint portions 23c and 23d. Moreover, cutouts 22f are formed in the holder 22 so that the female screw holes 23e of the transmission member 23 are exposed to the outside in a state in which the direction of eccentricity of the holder coincides with the extension direction of the conrod 31a when the conrod 31a is fixed to the transmission member 23 of the holder 22 at the secure engagement portion 31a1.

[0054] The screw members 26 are shoulder bolts each including a head portion that is an operation portion, a shaft portion that extends from the head portion and that does not have a male thread, and a male screw portion that is nearer to the tip than the shaft portion and that has a male thread. Each of the cutouts 22f of the holder 22 has such a size that, when the screw member 26 is screwed into the female screw hole 23e of the transmission member 23, the cutout 22f does not interfere with the shaft portion of the screw member 26, and, in a state in which the screw member 26 has been screwed into the female screw hole 23e, there is only a small gap between the shaft portion of the screw member 26 and a side surface of the holder 22 at the position of the cutout 22f. Cutouts 21f are formed in the crank hub 21 so as to avoid interference with the head portions of the screw members 26.

[0055] With the structure of the eccentric driving mechanism 20, by removing the screw members 26, which have been screwed into the second joint portion 23d of the transmission member 23 to connect the conrod 31a of the easing rod 31 to the transmission member 23, from the second joint portion 23d and by screwing the screw members 26 into the female screw holes 23e, a peripheral surface the shaft portion of the screw member 26 faces the side surface of the holder 22 at the position of the cutout 22f. Then, relative rotation of the holder 22 and the transmission member 23 is prohibited due to contact between the peripheral surface of the shaft portion of the screw member 26 and the side surface of the holder 22. The holder 22 is fixed to the crank hub 21, which is fixed to the driving shaft 13. Accordingly, in the state in which the screw members 26 are screwed into the female screw holes 23e, the transmission member 23 is unrotatable relative to the driving shaft 13.

[0056] In the structure described above, the easing roller 1 is shifted to the retracted position as follows.

[0057] First, the loom is stopped in a state in which the main shaft of the loom is at such a rotation angle that the direction of eccentricity of the eccentric driving mechanism 20 of the easing mechanism E1 coincides with the extension direction of the easing rod 31 (the state shown in Figs. 4A and 4B). Then, the screw members 26 are removed from the second joint portion 23d of the transmission member 23 and respectively screwed into the female screw holes 23e while the loom is stopped. By doing so, the easing rod 31 becomes rotatable relative to the transmission member 23 (eccentric driving mechanism 20) around the connection pin 25 fixed thereto, which serves as a connection shaft; and the transmission member 23, the crank hub 21, and the holder 22 become unrotatable relative to the driving shaft 13.

[0058] In this state, the main shaft of the loom is rotated by jogging the loom so that the driving shaft 13 is rotated by 180°. As the driving shaft 13 is rotated, the crank hub 21 and the holder 22 rotate, and the transmission member 23 rotates. Then, the connection pin 25, which has an axis 25a at a position eccentric to the axis 13a of the driving shaft 13, revolves around the axis of the driving shaft 13 by 180° and enters a state illustrated in Fig. 6. Accordingly, as illustrated in Figs. 7A and 7B, the connection pin 25 is shifted to a position that is displaced forward from the axis 13a of the driving shaft 13 by the amount of an eccentricity d2 of the axis 25a thereof with respect to the axis 13a of the driving shaft 13. As a result, due to the rotation of the driving shaft 13, the connection pin 25 becomes displaced from its position before the rotation by a distance that is twice the eccentricity d2. Thus, the easing rod 31 is moved forward by this distance, the easing lever 32 is swung by a swing amount corresponding to the distance, and thereby the easing roller 1 is swung by a large amount and moved to the retracted position.

[0059] During the operation of moving (shifting) the easing roller 1 to the retracted position as described above, the connection pin 25, which serves as a rotation shaft, functions as an eccentric shaft in the present invention, and the back end portion of the easing rod 31 (conrod 31a), into which the connection pin 25 is fitted and fixed, corresponds to a connection portion in the present invention. The eccentricity d2 of the axis 25a of the connection pin 25 with respect to the axis 13a of the driving shaft 13 corresponds to a second eccentricity in the present invention. In the present embodiment, the screw members 26 correspond to an engagement member that prohibits relative rotation of the transmission member 23 and the shaft portion 22b of the holder 22 (rotation shaft).

[0060] In Figs. 7A and 7B, an eccentricity d1 is the eccentricity of the axis 22b1 of the shaft portion 22b of the holder 22 with respect to the axis 13a of the driving shaft 13, which serves as the basis of an easing motion during weaving. In the example shown in the figures, the eccentricity d2, which serves as the basis of a swinging motion for moving the easing roller 1 to the retracted position, is about 16 times the eccentricity d1. The eccentricity d2, that is, the position of the connection shaft (connection pin 25) with respect to the axis 13a of the driving shaft 13, is set so that the easing roller 1 can be swung upward and displaced to such a position that the lower end of the easing roller 1 is located above the upper end of the warp beam WB. In the example shown in the figures, the swing amount of the easing roller 1 during retraction corresponds to an angle larger than 45° as illustrated in Fig. 6 (in the state shown in the figures, about 48°) in contrast to the swinging mount during weaving, which is an angle range of about 2 to 3° as described above.

[0061] Thus, the retracting device for the easing roller 1 according to the present embodiment can shift the easing roller 1 to the retracted position by driving the active easing mechanism while maintaining the linked state of the link mechanism 30. Therefore, even when the height position of the easing roller 1 is set to be low in order to set the height of the warp line during weaving to be low, an operation of replacing the warp beam WB can be easily performed.

[0062] The two screw members 26 are used to securely engage the easing rod 31 with the transmission member 23, and the screw members 26 are also used as an engagement member. By enabling the screw members 26, which function as an engagement member, to be used also during weaving and thereby using the screw members 26 in two ways, an advantage is obtained in that, it is not necessary to provide a space in which the engagement member is to be placed and to perform management for preventing loss of the engagement member during weaving when the engagement member is not needed. Moreover, as in the present embodiment, with the structure in which the easing rod 31 is made to be securely engaged with the transmission member 23 by using the two screw members 26, an advantage is obtained in that the operation for retracting the easing roller 1 can be easily performed, while using the screw members 26 in two ways as described above. To be specific, this advantage is as follows.

[0063] In the case in which the screw members 26 are used in two ways as described above, when the screw members 26 are used as an engagement member, it is necessary to remove the screw members 26, which have been screwed into the transmission member 23 (second joint portion 23d) to securely engage the easing rod 31 with the transmission member 23, from the transmission member 23. If only one screw member 26 were used and when the secure engagement of the easing rod 31 using the screw member 26 were released, in the easing mechanism E1, the easing rod 31 would become rotatable relative to the transmission member 23 around the connection pin 25 while the transmission member 23 remains rotatable relative to the holder 22 (shaft portion 22b).

[0064] Due to the weight of the easing roller 1, a force is applied to the link mechanism 30 of the easing mechanism E1 so that the easing lever 32 in the state shown in Fig. 1 is rotated in the clockwise direction in Fig. 1. The force is supported by the eccentric driving mechanism 20. However, if the secure engagement at the middle portion of the easing rod 31 is released in a state in which the transmission member 23 is rotatable as described above, a force in the rotational direction due to the weight of the easing roller 1 is applied to the transmission member 23 via the link mechanism 30, and thereby the transmission member 23 might be rotated from the state during the stoppage of the loom. In this case, the positions of the cutouts 22f of the holder 22 and the positions of the female screw holes 23e of the transmission member 23 become displaced from each other, so that the screw members 26 cannot be inserted into the female screw holes 23e of the transmission member 23. Therefore, if the transmission member 23 is rotated as described above, it is necessary to perform an operation of rotating the transmission member 23 to its original position. The operation, for rotating the transmission member 23 to its original position against the weight of the easing roller 1, requires a considerable effort.

[0065] In contrast, with the structure according to the present embodiment, the two screw members 26 are used to securely engage the easing rod 31 with the transmission member 23. Therefore, when one of the screw members 26 is removed from the transmission member 23, the secure engagement of the easing rod 31 with the transmission member 23 is not released. By screwing the removed screw member 26 into the female screw hole 23e of the transmission member 23, the transmission member 23 is made to be unrotatable relative to the holder 22. In this state, when the secure engagement of the easing rod 31 with the transmission member 23 is released by removing the other screw member 26 from the transmission member 23, the aforementioned rotation of the transmission member 23 due to the weight of the easing roller 1 does not occur. Accordingly, it is not necessary to perform the aforementioned operation for making the positions of the cutouts 22f of the holder 22 and the female screw holes 23e of the transmission member 23 to coincide with each other. Therefore, an operation performed on the easing mechanism E1 to move the easing roller 1 to the retracted position can be easily performed.

[0066] However, in a case where a dedicated member is used as an engagement member, the number of members (screw members 26) for securely engaging the easing rod 31 with the transmission member 23 may be one. In this case, the number of engagement members need not be two as in the present embodiment but may be one.

[0067] In the present embodiment, as a structure for prohibiting relative rotation of the transmission member 23 and the holder 22 (shaft portion 22b) by using engagement members, the cutouts 22f are formed in the holder 22, and the side surface of the holder 22 at the positions of the cutouts 22f are in contact with the peripheral surfaces of the shaft portions of the screw members 26, which are shoulder bolts. Instead of the cutouts 22f, for example, through-holes may be formed in the holder 22 so that the screw member 26 can be screwed into the female screw holes 23e of the transmission member 23 through the through-holes. In this case, due to the contact between the shaft portions of the screw members 26 and the inner peripheral surfaces of the through-holes, relative rotation of the transmission member 23 and the holder 22 is prohibited. In a case where a dedicated member is used as an engagement member, for example, a hook-like member having an inverted U-shape may be used as the engagement member. In this case, one end of the hook-like member may be fitted into the transmission member 23 and the other end of the hook-like member may be fitted into the holder 22.

[0068] In the structure according to the present embodiment shown in the figures, the cutouts 22f formed in the holder 22 are each larger than the diameter of the shaft portion of the screw member 26 in the direction along the outer periphery of the holder 22. This is not necessary if it were always possible to stop the loom from a weaving state so that the rotation angle (stop angle) of the main shaft is a predetermined rotation angle, that is, a rotation angle at which the direction of eccentricity of the eccentric driving mechanism 20 completely coincides with the extension direction of the easing rod 31. In practice, however, the stop angle of the main shaft is not always the same and the main shaft may stop at a rotation angle that slightly deviates from the predetermined rotation angle. By forming the cutouts 22f in the holder 22 so as to each have a lager size as described above, such deviation of the stop angle of the main shaft can be resolved.

[0069] Accordingly, also in the case where the through-holes for inserting the screw members 26 are formed in the holder 22 as described above, it is preferable that the through-holes be elongated holes that are elongated along a circle centered at the axis 13a of the driving shaft 13. In the structure shown in the figures, the cutouts 22f are each formed so as to allow for a deviation of a rotation angle of about 3° from the predetermined rotation angle. However, in a case where it is possible to control the loom so that the main shaft can be stopped at a predetermined stop angle without fail, the cutouts 22f and the through-holes formed in the holder 22 may be formed so as to substantially coincide with the outer peripheral surfaces of the shaft portions of the screw members 26.

[0070] In the present embodiment, the easing roller 1 also functions as a tension detection roller. However, this is not a limitation on the present invention. Alternatively, the tension of the warp yarns T may be detected by using another roller or the like, and the easing roller 1 may only function to perform an easing motion. The present embodiment has a both-side driving structure, in which the easing mechanisms E1 are disposed on both sides of the loom (on the left and right loom frames F) and connected to both end portions of the second support shaft 9, and the easing roller 1 is positively driven at the both end portions thereof. Alternatively, a one-side driving structure, in which the easing mechanism E1 is connected only to one end of the second support shaft 9, may be used.

[0071] In the above-described embodiment, an easing roller retracting device for a loom according to the present invention, which uses a crank-type active easing mechanism as an easing mechanism, has been described. However, according to another embodiment (modified embodiment) of the present invention, an easing roller retracting device may be configured as described below.

[0072] (1) In a case where a crank-type active easing mechanism is used as an easing mechanism of an easing roller retracting device according to the present invention, an easing mechanism E2 illustrated in Figs. 8A to 9B may be used instead of the above-described embodiment. Regarding the link mechanism 30, the easing mechanism E2 basically has the same structure as the above-described embodiment. Therefore, in Figs. 8A to 9B, the elements the same as those of the above-described embodiment will be denoted by the same numerals and detailed descriptions of such elements will be omitted. The easing mechanism E2 includes, as a driving device, an eccentric driving mechanism 40 different from that of the above-described embodiment.

[0073] The eccentric driving mechanism 40 includes a crank disc 41, an eccentric shaft 43, and a position adjusting mechanism 45. The crank disc 41, which serves as a driving member, is supported by the driving shaft 13 so as to be unrotatable relative to the driving shaft 13. The eccentric shaft 43 is supported by the crank disc 41 and is disposed at a position at which an axis 43a is eccentric to the axis 13a of the driving shaft 13. The position adjusting mechanism 45 is disposed so as to be unrotatable relative to the crank disc 41, supports the eccentric shaft 43, and is used to adjust the position of the eccentric shaft 43 in the radial direction of the crank disc 41 (hereinafter, simply referred to as the "radial direction"). Accordingly, the eccentric shaft 43 is supported by the crank disc 41 via the position adjusting mechanism 45. The easing rod 31 of the link mechanism 30 is connected to the eccentric shaft 43 at a connection portion at a back end thereof so as to be rotatable relative to the eccentric shaft 43 via a bearing member, such as a bearing metal. In the same way as in the above-described embodiment, synchronously with the rotation of the main shaft of the loom, the driving shaft 13 is driven once when the main shaft rotates once. Accordingly, the crank disc 41 is rotated once when the main shaft rotates once.

[0074] The position adjusting mechanism 45 includes a ball screw 45a, which is supported by the crank disc 41 so as to extend in the radial direction, and a driven nut 45b, which supports the ball screw 45a. To be specific, the ball screw 45a is supported by a pair of brackets 45c, which are fixed to a front surface of the crank disc 41 (an end surface farther from the driving shaft 13) so as to straddle the center of the crank disc and so as to extend from a position near the center to a position near an outer peripheral edge of the crank disc 41. The ball screw 45a is rotatably supported by the brackets 45c at shaft portions 45a1 at both ends thereof. One of the shaft portions 45a1 near an outer periphery of the crank disc 41 protrudes from the bracket 45c. The ball screw 45a is rotated and operated by using a tool (not shown) connected to the protruding portion. The shaft portions 45a1 of the ball screw 45a can be securely engaged by using a secure engagement piece (not shown). When the shaft portions 45a1 are securely engaged, the ball screw 45a is unrotatable relative to the bracket 45c.

[0075] The driven nut 45b includes a rectangular-parallelepiped-shaped body and has a through-hole 45b2 extending therethrough in the longitudinal direction. A female thread, which meshes with the ball screw 45a, is formed in the inner peripheral surface of the through-hole 45b2. The driven nut 45b further includes a guide piece 45b1 on one of two side surfaces, which are two of four side surfaces parallel to the axis of the through-hole 45b2. The guide piece 45b1 protrudes from the side surface and has a width smaller than that of the side surface. A guide groove 41a is formed in the crank disc 41 at the same position as the ball screw 45a in a front view. The guide groove 41a extends in the radial direction, and the guide piece 45b1 of the driven nut 45b can be fitted into the guide groove 41a. The driven nut 45b is supported by the ball screw 45a by screwing the ball screw 45a into the through-hole 45b2. In a state in which the driven nut 45b is supported by the ball screw 45a, the guide piece 45b1 is fitted into the guide groove 41a of the crank disc 41. Accordingly, due to the engagement of the guide piece 45b1 with the guide groove 41a, the driven nut 45b is unrotatable relative to the crank disc 41 and is displaceable in the longitudinal direction of the guide groove 41a (the radial direction and the extension direction of the ball screw 45a).

[0076] With the structure of the eccentric driving mechanism 40, when the ball screw 45a is rotated, the driven nut 45b becomes displaced along the ball screw 45a in the radial direction. Accordingly, when the ball screw 45a is rotated, the position of the eccentric shaft 43, which is supported by the driven nut 45b, on the crank disc 41 in the radial direction is changed. Thus, the eccentricity of the axis 43a of the eccentric shaft 43 with respect to the axis 13a of the driving shaft 13 is changed.

[0077] In the structure shown in the figures, the ball screw 45a extends from a position near an outer peripheral edge of the crank disc 41 toward the center of the crank disc 41 (the position of the axis 13a of the driving shaft 13) and to a position beyond the center. Accordingly, the position of the driven nut 45b near the center of the crank disc 41 can be set at such a position that the axis 43a of the eccentric shaft 43 is located adjacent to the axis 13a of the driving shaft 13 in the radial direction.

[0078] During weaving, for example, the position of the driven nut 45b is set at such a position (with an eccentricity d3) that the axis 43a of the eccentric shaft 43 is located adjacent to the axis 13a of the driving shaft 13 in the radial direction, as shown by a solid line in Fig. 8C. The easing roller 1 performs an easing motion in a range shown by a solid line and a two-dot chain line in Fig. 9A. The eccentricity d3 at this time corresponds to a first eccentricity in the present invention. With the eccentric driving mechanism 40, the position of the driven nut 45b on the ball screw 45a, that is, the position of (= the eccentricity of) the axis 43a of the eccentric shaft 43 with respect to the axis 13a of the driving shaft 13 in the radial direction, can be freely set within a region in which the ball screw 45a is present. Accordingly, the position of the driven nut 45b (eccentric shaft 43) during weaving can be freely set in accordance with the weaving condition and the like. However, as described above in the embodiment, because the swing amount of the easing roller 1 due to an easing motion during weaving is small, any position of the driven nut 45b (eccentric shaft 43) that can be set for an easing motion is in such a range that the axis 43a of the eccentric shaft 43 is located adjacent to the axis 13a of the driving shaft 13. As long as the position of the axis 43a is in the range that can be set for the easing motion, any eccentricity of the axis 43a of the eccentric shaft 43 with respect to the axis 13a of the driving shaft 13 corresponds to a first eccentricity.

[0079] In the easing mechanism E2, the position of the driven nut 45b (eccentric shaft 43) on the ball screw 45a can be changed to a position that is beyond the range that can be set for an easing motion during weaving. The maximum value of the change (the maximum change amount) is set so that the easing roller 1 can be moved to a retracted position. The maximum change amount is set so that the easing roller 1 can be shifted to a position at which the lower end of the easing roller 1 is located above the upper end of the warp beam WB on the basis of the relationship between the position of the easing roller 1 and the position of the upper end of the warp beam WB in the vertical direction during weaving. The diameter of the crank disc 41 and the length of the ball screw 45a are set so that the maximum change amount can be realized.

[0080] When retracting the easing roller 1, by rotating the ball screw 45a, the driven nut 45b is displaced to a position corresponding to the maximum change amount (the position shown by a broken line in Fig. 8C), which is beyond a range that can be set for an easing motion. By doing so, the eccentricity d4 of the axis 43a of the eccentric shaft 43 with respect to the axis 13a of the driving shaft 13 becomes considerably larger than the first eccentricity d3 for an easing motion. In the example shown in the figures, the eccentricity d4 is more than 10 times larger than the eccentricity d3. The eccentricity d4 corresponds to a second eccentricity in the present invention. In this state, the loom is jogged to rotate the driving shaft 13 to a phase at which the easing mechanism E2 is at the dead center and the easing roller 1 is at the foremost position, and thereby the easing roller 1 is shifted to a retracted position shown by a solid line in Fig. 9B. A two-dot chain line in Fig. 9B shows a state in which the easing roller 1 is moved to the backmost position in an easing motion during weaving.

[0081] The structure of an adjusting mechanism for adjusting the eccentricity of the axis of the eccentric shaft with respect to the axis of the driving shaft of a crank-type active easing mechanism is not limited to the structure described above. Alternatively, for example, a structure described in Japanese Unexamined Patent Application Publication No. 7-133545, in which a spiral groove is formed in a crank disc and the position of an eccentric shaft is adjusted along the spiral groove, may be used. However, also in this case, the spiral groove in the crank disc is formed so that the position of the eccentric shaft can be set at a position beyond the adjustment range of the eccentric shaft for performing an easing motion during weaving.

[0082] (2) In the above-described embodiment and the modified embodiment, a crank-type active easing mechanism is used as an easing mechanism of an easing roller retracting device according to the present invention. However, this is not a limitation on the present invention. Alternatively, the easing mechanism may be, for example, a cam-driving-type active easing mechanism illustrated in Figs. 10A to 11B.

[0083] Figs. 10A to 11B illustrate an easing mechanism E3 including a cam driving mechanism 50 as a driving device. Regarding the link mechanism 30, the easing mechanism E3 basically has the same structure as the above-described embodiment. Therefore, in Figs. 10A to 11B, the elements the same as those of the above-described embodiment will be denoted by the same numerals and detailed descriptions of such elements will be omitted.

[0084] The cam driving mechanism 50 of the easing mechanism E3 includes a cam 51, which is rotated by the driving shaft 13, and a cam lever 52. The cam lever 52 is in contact with the cam 51 via a cam ball 52d (cam follower) and is connected to the easing rod 31 of the link mechanism 30. In the same way as in the above-described embodiment, synchronously with the rotation of the main shaft of the loom, the driving shaft 13 rotates once when the main shaft rotates once. Accordingly, the crank disc 41 is rotated once when the main shaft rotates once.

[0085] The cam lever 52 includes a boss portion 52a, which is rotatably supported by the loom frame F via a support shaft 54; and two lever portions 52b and 52c, which are integrally formed with the boss portion 52a so as to extend toward both sides of the boss portion 52a with the boss portion 52a interposed therebetween. In the example shown in the figures, the lever portion 52b, which is one of the two lever portions 52b and 52c, extends downward from the boss portion 52a. A shaft 52b1 is fixed to a distal end portion (end portion farther from the boss portion 52a) of the lever portion 52b, and the cam ball 52d is rotatably supported by the shaft 52b1. The cam lever 52 is disposed so that the position of the cam ball 52d, which is supported by the lever portion 52b, coincides with the position of the cam 51 in the weaving-width direction. The lever portion 52b of the cam lever 52 is urged toward the cam 51 by urging means (not shown), such as a spring, so as to maintain contact between the cam ball 52d and the cam 51.

[0086] The lever portion 52c of the cam lever 52 extends upward from the boss portion 52a. The lever portion 52c extends along an arc centered at a connection shaft that connects the easing rod 31 and the easing lever 32 to each other in a state in which the easing roller 1 is at the backmost position (a state in which the cam ball 52d is in contact with the bottom dead center of the cam 51). A connection member 53, to which the back end portion of the easing rod 31 is connected, is attached to the lever portion 52c.

[0087] The connection member 53 includes a body 53a, which is attached to the lever portion 52c of the cam lever 52; and a shaft portion 53b, which protrudes from the body 53a and is connected to the easing rod 31. To be specific, the body 53a has a substantially rectangular-parallelepiped shape and has a through-hole 53a1, into which the lever portion 52c of the cam lever 52 can be fitted. The body 53a is fitted onto the lever portion 52c at the through-hole 53a1. Moreover, by screwing a secure engagement bolt 53c into a female screw hole, which is connected from a side surface to the through-hole 53a1, the body 53a is attached to the cam lever 52 so that the position of the body 53a on the lever portion 52c is fixed. The shaft portion 53b is disposed on a side surface 53a2 of the body 53a, which is one of side surfaces in the width direction (the axial direction of the support shaft 54 of the cam lever 52) farther from the cam 51, so as to protrude in the width direction.

[0088] The body 53a has a width larger than that of the boss portion 52a so that, in a state in which the body 53a is attached to the cam lever 52, the side surface 53a2, on which the shaft portion 53b is disposed, is located at a position separated farther from (outward from) the cam 51 than the boss portion 52a of the cam lever 52 is. Moreover, a through-hole 52a1 is formed near a side surface opposite from the side surface 53a2. Accordingly, in a front view, in a state in which the body 53a is attached to the cam lever 52, the body 53a protrudes outward from the boss portion 52a of the cam lever 52. A part of a lower surface of the body 53a facing the boss portion 52a of the cam lever 52 is cut out in an arc shape along the outer peripheral surface of the boss portion 52a. Moreover, an outer end portion of the body 53a, including the side surface 53a2,
has a protruding portion that protrudes toward an axis 54a of the support shaft 54. Accordingly, with the structure of the body 53a, the shaft portion 53b, which is disposed on the side surface 53a2, can be disposed so that an axis 53b1 of the shaft portion 53b is located adjacent to the axis 54a of the support shaft 54 of the cam lever 52.

[0089] The shaft portion 53b of the connection member 53 is unrotatably fixed to the body 53a. The easing rod 31 is connected to the shaft portion 53b at a connection portion at a back end thereof via a bearing member, such as a bearing metal, so as to be rotatable relative to the shaft portion 53b. The connection member 53 is fixed to the lever portion 52c of the cam lever 52 so that the axis 53b1 of the shaft portion 53b is located at a position eccentric (with an eccentricity d5) to the axis 54a of the support shaft 54.

[0090] With the easing mechanism E3 including the cam driving mechanism 50 having such a structure, when the cam 51 is rotated by the driving shaft 13, the cam lever 52, which is in contact with the cam 51 via the cam ball 52d at the lever portion 52b, is swung back and forth around the axis 54a of the support shaft 54. In the present embodiment, the cam lever 52 corresponds to a driving member in the present invention, which is rotated by the driving shaft 13. In the present embodiment, the rotational driving of the driving member (cam lever 52) by the driving shaft 13 is not continuous rotation in one direction as in the above-described embodiments but is back-and-forth rotation. In the present embodiment, the shaft portion 53b of the connection member 53 supported by the cam lever 52 (driving member), which is disposed so that the axis 53b1 is eccentric to the axis 54a of the support shaft 54 supporting the cam lever 52, corresponds to an eccentric shaft in the present invention.

[0091] When the cam lever 52 swings back and forth, the shaft portion 53b of the connection member 53, which is disposed at a position at which the axis 53b1 is eccentric to the axis 54a of the support shaft 54, reciprocates in the front-back direction by an amount corresponding to the eccentricity, and the easing rod 31, which is connected to the shaft portion 53b, is reciprocated in the front-back direction. As a result, the easing roller 1 swings with a swing amount corresponding to the eccentricity.

[0092] During weaving, as illustrated in Figs. 10A and 10B, the position of the connection member 53 on the lever portion 52c of the cam lever 52 is set at a position adjacent to the boss portion 52a of the cam lever 52. The eccentricity of the axis 53b1 of the shaft portion 53b of the connection member 53 with respect to the axis 54a of the support shaft 54 is the eccentricity d5 shown in Fig. 10B, which is small. Accordingly, during weaving, the easing roller 1 performs an easing motion with a swing amount corresponding to the eccentricity d5. The eccentricity d5 at this time corresponds to a first eccentricity in the present invention. In Fig. 10A, a state in which the easing roller 1 is located at the backmost position (a state in which the cam ball 52d is in contact with the bottom dead center of the cam 51) is shown by a solid line. A state in which the easing roller 1 is at the foremost position (a state in which the cam ball 52d is in contact with the top dead center of the cam 51) is shown by a two-dot chain line.

[0093] In the structure shown in the figures, the lever portion 52c of the cam lever 52 extends upward over such a length that the eccentricity of the axis 53b1 of the shaft portion 53b of the connection member 53 can be set at a value exceeding the eccentricity that can be set for an easing motion during weaving. In a state in which the connection member 53 is located near a distal end of the lever portion 52c, the eccentricity d6 (Fig. 11B) of the axis 53b1 of the shaft portion 53b of the connection member 53 is considerably larger than the aforementioned eccentricity d5 during weaving. In the example shown in the figures, the eccentricity d6 is more than 6 times larger than the eccentricity d5.

[0094] When retracting the easing roller 1, first, the secure engagement bolt 53c, which fixes the position of the connection member 53 relative to the cam lever 52, is loosened so that the connection member 53 becomes movable along the lever portion 52c. Then, the connection member 53 is moved toward the distal end of the lever portion 52c, and the connection member 53 is fixed again near the distal end of the lever portion 52c by using the secure engagement bolt 53c. By doing so, as illustrated in Fig. 10B, the axis 53b1 of the shaft portion 53b of the connection member 53 becomes eccentric to the axis 54a of the support shaft 54 with the eccentricity d6, which is large. The eccentricity d6 at this time corresponds to a second eccentricity in the present invention. The connection member 53 is moved as described above in a state in which the easing roller 1 is located at the backmost position.

[0095] In this state, the main shaft of the loom is rotated by jogging the loom so that the driving shaft 13 is rotated by 180°. As the driving shaft 13 is rotated, the cam 51 rotates, and thereby the cam lever 52 swings forward. At this time, because the shaft portion 53b of the connection member 53 is eccentric to the support shaft 54 with the large eccentricity d6, the shaft portion 53b becomes displaced forward by a distance equal to the length of an arc having a radius corresponding to the eccentricity d6. As a result, the easing lever 32, which is connected to the shaft portion 53b of the connection member 53 via the easing rod 31, is swung by a large amount, and the easing roller 1 is shifted to the retracted position shown by a solid line in Fig. 11A. The state shown by a two-dot chain line in Fig. 11A is a state in which the easing roller 1 is moved to the backmost position due to an easing motion during weaving.

[0096] In the embodiments described above with reference to Figs. 8A to 11B, the eccentric shaft is common to an operation during weaving and an operation during retraction of the easing roller 1. The position of the common eccentric shaft can be switched between the eccentric position that is used during weaving (position at which the axis is eccentric to the axis of the support shaft (driving shaft) with a first eccentricity) and the eccentric position that is used when retracting the easing roller 1 (position at which the axis is eccentric to the axis of the support shaft (driving shaft) with a second eccentricity). However, in the case of these structures, the driving member, which supports the eccentric shaft, needs to be large enough to allow the two eccentric positions to be set. Although this is feasible, the structure has a problem in that the size of the device is increased. In contrast, in the case of the above-described embodiment, with which the eccentric shafts are switched between an eccentric shaft that is used during weaving and an eccentric shaft that is used when retracting the easing roller 1 as described above, has an advantage that the size of the device can be reduced.

[0097] In the embodiments described above, the driving shaft 13 is connected to the main shaft of the loom and rotated by the main shaft of the loom. In other words, the main shaft of the loom serves as a driving source. However, this is not a limitation on the present invention. Alternatively, the driving shaft 13 may have a dedicated driving motor, which is independent from the main shaft (main driving motor), as a driving source, and may be rotated by the dedicated driving motor synchronously with the main shaft of the loom.

[0098] (3) In the embodiments described above, an active easing mechanism is used as an easing mechanism of an easing roller retracting device according to the present invention. However, this is not a limitation on the present invention. Alternatively, the easing mechanism may be a passive easing mechanism that does not include a driving device and that absorbs variation of the tension of the warp yarns T during weaving by using an urging force of a spring or the like.

[0099] Fig. 12 illustrates an example in which a passive easing mechanism E4, which absorbs variation of the tension of the warp yarns T during weaving by using an easing spring 37, is used as an easing mechanism according to the present invention. In the easing mechanism E4, the easing spring 37, which is a compression spring, is disposed between the easing lever 32 and an easing rod 35. Due to an urging force applied by the easing spring 37 to the easing lever 32, a tension is applied to the warp yarns T and variation of the tension of the warp yarns T during weaving is absorbed. In the passive easing mechanism E4, the easing rod 35 is supported by the loom frame at an end portion (back end portion), the end portion being opposite from the end at which the easing rod 35 is connected to the easing lever 32, via a bearing member, such as a spherical bearing, attached to the end portion.

[0100] In the structure shown in the figures, the effective rod length of the easing rod 35 (the length from a support position at which the easing rod 35 is supported by the loom frame to a position at which the easing rod 35 is connected to the easing lever 32) can be changed. To be specific, the easing rod 35 includes two rod members, which are a first rod member 35a connected to the easing lever 32 and a second rod member 35b supported by the loom frame. The first and second rod members 35a and 35b are connected to each other through a rod-length adjusting device 60.

[0101] The rod-length adjusting device 60 includes a first connection member 61, a second connection member 62, and a ball screw 63. The first connection member 61 is unrotatably fixed to a back end portion of the first rod member 35a. The second connection member 62 is unrotatably fixed to an end portion (front end portion) of the second rod member 35b on the easing lever 32 side with a phase that is the same as that of the first connection member 61 with respect to the easing rod 35. The ball screw 63 connects the first connection member 61 and the second connection member 62 to each other. The ball screw 63 is supported by the first connection member 61 at a shaft portion 63a, which is formed at a front end portion thereof, and is supported by a support member 64 at a shaft portion 63b, which is formed at a back end portion thereof. The support member 64 is fitted onto the second rod member 35b at a through-hole 64a, so that the support member 64 is slidable relative to the second rod member 35b in the axial direction of the second rod member 35b. The ball screw 63 is rotatably supported by the first connection member 61 and the support member 64 respectively at the shaft portions 63a and 63b at both ends thereof so as to be immovable in the axial direction.

[0102] The second connection member 62 has a through-hole 62a at a position at which the second connection member 62 crosses the ball screw 63, which is supported by the first connection member 61. A female thread, which can mesh with the male thread of the ball screw 63, is formed in the inner peripheral surface of the through-hole 62a. The second connection member 62 is screwed onto the ball screw 63 at the through-hole 62a between the first connection member 61 and the support member 64.

[0103] Accordingly, with the structure of the rod-length adjusting device 60, by rotating the ball screw 63, the position of the second connection member 62 on the ball screw 63 is changed. Therefore, the distance between the first connection member 61 and the second connection member 62 (between the first rod member 35a and the second rod member 35b) in the axial direction of the easing rod 31 is changed. As a result, the effective rod length of the easing rod 35 is changed. The ball screw 63 may be rotated by connecting a tool (not shown) or the like to a part of the shaft portion 63b of the ball screw 63 protruding from the support member 64.

[0104] With the retracting device for the easing roller 1 according to the present invention, which includes the passive easing mechanism E4 described above, during weaving, the position of the second connection member 62 on the ball screw 63 is set at a position at which an end portion of the first rod member 35a and an end portion the second rod member 35b that face each other are located close to each other but do not contact each other. During retraction of the easing roller 1, the ball screw 63 is rotated in such a direction that the distance between the first connection member 61 and the second connection member 62 is increased. Because the second rod member 35b, to which the second connection member 62 is fixed, is fixed in position by being supported by the loom frame at a back end portion thereof, the position of the second connection member 62 does not change in the axial direction of the easing rod 35. Accordingly, as the ball screw 63 is rotated as described above, the first connection member 61 becomes displaced in a direction in which the first connection member 61 is separated from the second connection member 62 in the axial direction of the easing rod 35. As a result, the first rod member 35a, to which the first connection member 61 is fixed, becomes displaced toward the easing lever 32, and thereby the easing lever 32 is swung and the easing roller 1 becomes displaced upward.

[0105] As the ball screw 63 is rotated as described above, the support member 64 slides over the second rod member 35b toward the second connection member 62. Until the support member 64 contacts the second connection member 62, the ball screw 63 can be rotated as described above, or, in other words, the second connection member 62 (second rod member 35b) can be displaced in the axial direction of the easing rod 35 relative to the first connection member 61 (first rod member 35a). The amount of displacement is set in accordance with the distance between the second connection member 62 and the support member 64 (the length of the ball screw 63) during weaving. The distance is set at such a value that the easing roller 1 is moved to the retracted position due to the swing of the easing lever 32 caused by the displacement of the first rod member 35a. Accordingly, by rotating the ball screw 63 until the support member 64 contacts the second connection member 62, the easing roller 1 is shifted to the retracted position.

[0106] The function of the passive easing mechanism E4 can be applied to the active easing mechanism E2 described with reference to Figs. 8A to 8C. In the above description of the active easing mechanism E2, the position of the driven nut 45b is displaced to such a position that the axis of the eccentric shaft 43 has the second eccentricity with respect to the axis 13a of the driving shaft 13, and then the easing roller 1 is shifted to the retracted position by rotating the driving shaft 13. Alternatively, while the loom is stopped, first, the main shaft (driving shaft 13) may be rotated to an angle corresponding to the foremost position of the easing roller 1 in an easing motion during weaving, and then the ball screw 45a may be rotated so as to move the driven nut 45b to such a position that the eccentric shaft 43 has the second eccentricity with respect to the axis 43a of the eccentric shaft 43. In this case, as the driven nut 45b becomes displaced, the easing roller 1 becomes displaced upward, and the easing roller 1 is shifted to the retracted position in a state in which the eccentricity of the axis 43a of the eccentric shaft 43 is the second eccentricity.

[0107] In the active easing mechanism E2 illustrated in Figs. 8A to 8C and in the passive easing mechanism E4 illustrated in Fig. 12, the ball screws 45a and 63 may be electrically rotated by using a dedicated actuator or the like, instead of using a tool as described above.

[0108] The present invention is not limited to any of the embodiments described above, and the embodiments can be modified in various ways within the sprit and scope of the present invention.

Claims

1. An easing roller retracting device for a loom, the loom including an easing roller (1) and an easing mechanism (E1, E2, E3, E4), the easing roller (1) swingably supported by a loom frame (F) and warp yarns (T) let off from a warp beam (WB) being looped over the easing roller (1), a position of the easing roller (1) during weaving being set so that at least a part of the easing roller (1) is located below an upper end of the warp beam (WB) in a vertical direction, the easing mechanism (E1, E2, E3, E4) being connected to the easing roller (1) and swinging the easing roller (1) to absorb variation of a tension of the warp yarns (T) in each loom cycle for weaving,
wherein the easing mechanism (E1, E2, E3, E4) is capable of swinging and displacing the easing roller (1) to a retracted position that is beyond a swing range of the easing roller (1) during weaving and at which a lower end of the easing roller (1) is located above the upper end of the warp beam (WB) in the vertical direction.

2. The easing roller retracting device according to Claim 1,
wherein the easing mechanism (E1, E2, E3, E4) is an active easing mechanism (E1, E2, E3) including a link mechanism (30) connected to the easing roller (1), a driving shaft (13) that rotates synchronously with a main shaft of the loom, a driving member (21, 41, 52) supported and rotated by the driving shaft (13), and an eccentric shaft (22b, 25, 43, 53b) supported by the driving member (21, 41, 52) at a position at which an axis (22b1, 25a, 43a, 53b1) thereof is eccentric to an axis of a support shaft that supports the driving member (21, 41, 52), the eccentric shaft (22b, 25, 43, 53b) imparting a reciprocating motion in a front-back direction to the link mechanism (30) by being connected to a connection portion that is provided at one end portion of an easing rod (31) that is included in the link mechanism (30), the one end portion being farther from the easing roller (1), and
wherein the active easing mechanism (E1, E2, E3) is capable of setting an eccentricity of the axis (22b1, 25a, 43a, 53b1) of the eccentric shaft (22b, 25, 43, 53b) with respect to the axis of the support shaft at a first eccentricity (d1, d3, d5) and a second eccentricity (d2, d4, d6), the first eccentricity (d1, d3, d5) being an eccentricity during weaving, the second eccentricity (d2, d4, d6) being an eccentricity for shifting the easing roller (1) to the retracted position.

3. The easing roller retracting device according to Claim 2,
wherein the active easing mechanism (E1, E2, E3) is a crank-type active easing mechanism (E1) in which the driving member (21) is supported by the driving shaft (13),
wherein the crank-type active easing mechanism (E1) includes a rotation shaft (22b) that is supported by the driving member (21) and that is disposed at a position at which an axis (22b1) thereof is eccentric to the axis (13a) of the driving shaft (13), a transmission member (23) that is disposed so as to surround the rotation shaft (22b) and that is supported by the rotation shaft (22b) via a bearing (24) so as to be rotatable relative to the rotation shaft (22b), and an engagement member (26) that prohibits relative rotation of the rotation shaft (22b) and the transmission member (23),
wherein the easing rod (31) is rotatably connected to the transmission member (23) via a connection shaft (25) that is fitted into the one end portion, and the easing rod (31) is securely engageable with the transmission member (23) at a middle portion thereof,
wherein, during weaving, the easing rod (31) is securely engaged with the transmission member (23) at the middle portion so that rotation of the easing rod (31) relative to the transmission member (23) around the connection shaft (25) is prohibited and the transmission member (23) and the easing rod (31) are allowed to move together, the transmission member (23) functions as the connection portion, which is a part of the easing rod (31), the rotation shaft (22b) functions as the eccentric shaft, and an eccentricity of the axis (22b1) of the rotation shaft (22b) with respect to the axis (13a) of the driving shaft (13) becomes the first eccentricity (d1), and
wherein, when the easing roller (1) is retracted, the secure engagement of the easing rod (31) with the transmission member (23) is released so that the easing rod (31) is rotatable relative to the transmission member (23) around the connection shaft (25) and relative rotation of the transmission member (23) and the rotation shaft (22b) is prohibited by the engagement member (26), a part of the easing rod (31) into which the connection shaft (25) is fitted functions as the connection portion, the connection shaft (25) functions as the eccentric shaft, and the eccentricity of the axis (25a) of the connection shaft (25) with respect to the axis (13a) of the driving shaft (13) becomes the second eccentricity (d2).

Drawing