Knot-tying device and knot-tying method

Abstract

To provide a knot-tying device that can reliably tie the left and right strings together without making mistakes. [Solution] A string-tying device that ties the left and right strings 9 together by first wrapping the right string 9 around the right arm 45 and the left string 9 around the left arm 46, then clamping the left string 9 with the right arm 45 and clamping the right string 9 with the left arm 46, and then simultaneously pulling the right string 9 out of the right arm 45 and pulling the left string 9 out of the left arm 46.

Description

Technical Field

[0001] This invention relates to a string-tying device and a string-tying method for combining left and right strings.

Background Art

[0002] The applicant of the present application has already proposed the devices of Patent Documents 1 and 2 as a string-tying device for combining the left and right strings extending from a stringed article (for example, a stringed bag for storing grains such as rice and wheat).

[0003] The string-tying device of Patent Document 1 has a right rotating chuck, a left rotating chuck, and an auxiliary chuck. The right rotating chuck and the left rotating chuck each have a gripping claw for gripping a string at its tip, and are configured to be rotatable about an axis in the left-right direction while gripping the string with the gripping claw.

[0004] This string-tying device of Patent Document 1 grips the right string among the left and right strings extending from the stringed bag with the right rotating chuck, and grips the left string with the left rotating chuck. In this state, by rotating the right rotating chuck around the center of the chuck, the right string is wound around the outer periphery of the right rotating chuck. Next, the tip portion of the right string is transferred from the right rotating chuck to the auxiliary chuck, and then the tip portion of the left string is transferred from the left rotating chuck to the right rotating chuck, and further, the tip portion of the right string is transferred from the auxiliary chuck to the left rotating chuck. After that, while moving the left rotating chuck to the left and simultaneously moving the right rotating chuck to the right, the tip portion of the left string gripped by the right rotating chuck is passed through the wound portion of the right string wound around the outer periphery of the left rotating chuck, so as to combine the left and right strings.

[0005] However, the string-tying device described in Patent Document 1 has the problem that it cannot tie the left and right strings together at high speed because it sequentially performs string transfer operations from the right rotating chuck to the auxiliary chuck, from the left rotating chuck to the right rotating chuck, and from the auxiliary chuck to the left rotating chuck.

[0006] Therefore, in order to enable the fast tying of the left and right strings, the applicant of this application has proposed the string-tying device described in Patent Document 2.

[0007] The string-tying device of Patent Document 2 comprises a right-side chuck and a left-side chuck positioned separately to the left and right above a stringed bag; a chuck rotation mechanism that rotates both chucks together around a vertical pivot axis located midway between the right-side and left-side chucks; a right-side arm with opening and closing claws for gripping the string at its tip; a left-side arm with opening and closing claws for gripping the string at its tip; and an arm left-right movement mechanism that moves the right-side and left-side arms in the left-right direction.

[0008] The knot-tying device of Patent Document 2 first grasps the right knot with the right chuck and the left knot with the left chuck. In this state, the right chuck and the left chuck are rotated approximately 45° around a pivot axis located midway between them so that the right chuck moves to the rear and the left chuck moves to the front. Next, the right arm and the left arm are inserted between the right knot and the left knot so that the tips of the right arm and the left arm are pointing diagonally upward. At this time, the right arm and the left arm are crossed so that the right arm is at the rear and the left arm is at the front, and the opening and closing claws at the tip of the right arm and the tip of the left arm are both opened. In this state, the right chuck is moved to the front and the left chuck to the rear, and the right and left chucks are rotated approximately 45° in the return direction around a pivot axis located midway between the two chucks. This introduces the right string extending downward from the right chuck and the left string extending downward from the left chuck into the open opening / closing claws at the tip of the left arm and the open opening / closing claws at the tip of the right arm, respectively. Then, both the opening / closing claws at the tip of the right arm and the opening / closing claws at the tip of the left arm are closed to grip the strings, and in this state, the right and left arms are moved away from each other to tie the left and right strings together. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2015-113143 [Patent Document 2] Japanese Patent Publication No. 2021-041935 [Overview of the project] [Problems that the invention aims to solve]

[0010] As described above, the string-tying device of Patent Document 2 rotates the right and left chucks by approximately 45° in the return direction around a pivot axis located midway between the two chucks, thereby introducing the right string extending downward from the right chuck and the left string extending downward from the left chuck into the opening and closing claws at the tip of the left arm and the right arm, respectively. However, when the right and left chucks are rotated around a pivot axis located midway between the two chucks, slack tends to occur in the strings extending downward from the chucks, making the position of the strings unstable and prone to failure in introducing the left and right strings into the opening and closing claws at the tips of the left and right arms.

[0011] The problem that this invention aims to solve is to provide a string-tying device that can reliably tie together left and right strings without failure. [Means for solving the problem]

[0012] In order to solve the above problems, this invention provides a knot-tying device with the following configuration. [Configuration 1] A string-tying device for tying together strings extending from an item with a string attached, A right-side zipper and a left-side zipper are positioned separately to the left and right above the aforementioned stringed article, The right arm and the left arm are provided below the right chuck and the left chuck, extending in the left-right direction, and each arm has a clamp portion at its tip for gripping a string. A right-side chuck forward / backward movement mechanism for moving the right-side chuck in the forward / backward direction, A left chuck forward and backward movement mechanism for moving the left chuck in the forward and backward direction, A right arm forward / backward movement mechanism for moving the right arm in the forward / backward direction, A left arm forward / backward movement mechanism for moving the left arm in the forward / backward direction, A right arm left-right movement mechanism for moving the right arm in the left-right direction, It has a left arm left-right movement mechanism that moves the left arm in the left-right direction, With the right string gripped by the right chuck, the right arm forward / backward movement mechanism moves the right arm to one side in the forward / backward direction, and the right chuck movement mechanism moves the right chuck to the other side in the forward / backward direction, thereby performing the winding operation of the right string onto the right arm, so that the right string is wrapped around the outer circumference of the right arm from one side in the forward / backward direction. With the left string gripped by the left chuck, the left arm forward / backward movement mechanism moves the left arm to the other side in the forward / backward direction, and the left chuck forward / backward movement mechanism moves the left chuck to one side in the forward / backward direction, thereby performing the winding operation of the left string onto the left arm, so that the left string is wrapped around the outer circumference of the left arm from the other side in the forward / backward direction. After the winding operation of the right string onto the right arm and the winding operation of the left string onto the left arm, the right arm left-right movement mechanism moves the right arm to the left, and the clamp portion at the tip of the right arm grips the portion of the left string that is stretched between the left arm and the left chuck, thereby clamping the left string with the right arm, and the left arm left-right movement mechanism moves the left arm to the right, and the clamp portion at the tip of the left arm grips the portion of the right string that is stretched between the right arm and the right chuck, thereby clamping the right string with the left arm, A string-tying device that simultaneously performs the following actions to tie the left and right strings together: after the clamping operation of the left string by the right arm and the clamping operation of the right string by the left arm, the right arm is moved to the right using the right arm left-right movement mechanism while the clamp portion at the tip of the right arm is grasping the left string, and the right arm is pulled out from the portion of the right string that is wrapped around the outer circumference of the right arm; and the left arm is moved to the left using the left arm left-right movement mechanism while the clamp portion at the tip of the left arm is grasping the right string, and the left arm is pulled out from the portion of the left string that is wrapped around the outer circumference of the left arm.

[0013] With this configuration, when wrapping the right string around the right arm, the right arm is moved to one side in the front-to-back direction, and the right chuck is moved to the other side in the front-to-back direction. This allows the right string to be wrapped deeply around the outer circumference of the right arm from one side in the front-to-back direction, stabilizing the position of the right string. Similarly, when wrapping the left string around the left arm, the left arm is moved to the other side in the front-to-back direction, and the left chuck is moved to one side in the front-to-back direction. This allows the left string to be wrapped deeply around the outer circumference of the left arm from the other side in the front-to-back direction, stabilizing the position of the left string. Therefore, the operation of gripping the portion of the left string that is stretched between the left arm and the left chuck with the clamp at the tip of the right arm, and the operation of gripping the portion of the right string that is stretched between the right arm and the right chuck with the clamp at the tip of the left arm, are less likely to fail, making it possible to stably tie the left and right strings together.

[0014] [Configuration 2] The aforementioned right-side chuck forward and backward movement mechanism is a right-side pivot actuator that pivots the right-side chuck from a position aligned to the right of the right pivot axis to one side in the forward and backward direction, around the right pivot axis. The knot-tying device according to configuration 1, wherein the left-side chuck forward and backward movement mechanism is a left-side pivot actuator that pivots the left-side chuck from a position aligned to the left of the left pivot axis, which is aligned to the left of the right pivot axis, to the other side in the forward and backward direction, around the left pivot axis.

[0015] When this configuration is adopted, as a mechanism for moving the right chuck and the left chuck in the front-rear direction, a turning actuator is adopted that turns the right chuck and the left chuck around the right turning shaft and the left turning shaft arranged side by side left and right, respectively. Therefore, in the operation of winding the right string around the right arm of the right string, when moving the right chuck, the distance from the portion of the right string held by the right chuck to the root of the right string hardly changes, and it is possible to prevent the right string from sagging or being excessively pulled, and the position of the right string becomes stable. Similarly, in the operation of winding the left string around the left arm of the left string, when moving the left chuck, the distance from the portion of the left string held by the left chuck to the root of the left string hardly changes, and it is possible to prevent the left string from sagging or being excessively pulled, and the position of the left string becomes stable.

[0016] [Configuration 3] It has a right string transfer chuck that transfers the right string to the right chuck and a left string transfer chuck that transfers the left string to the left chuck. The right string transfer chuck is provided so as to transfer the middle portion of the right string to the right chuck. The string tying device according to Configuration 1 or 2, wherein the left string transfer chuck is provided so as to transfer the middle portion of the left string to the left chuck.

[0017] When this configuration is adopted, the right chuck and the left chuck will grip the middle portion of the string without gripping the tip portions of the right string and the left string. Here, the tip portions of the right string and the left string are the portions that constitute the straight portion of the string extending from the knot when the left and right strings are combined to form a knot. Therefore, when the left and right strings are combined to form a knot, it is possible to prevent the string from being broken or damaged due to the gripping of the chuck in the straight portion of the string extending from the knot.

[0018] [Configuration 4] The clamp portion at the tip of the right arm is configured to be switchable between an open state in which it does not grip the string, a semi-clamped state in which it grips the string in a direction that is perpendicular to the longitudinal direction of the string relative to the clamp portion while allowing movement of the string in the longitudinal direction relative to the clamp portion, and a fully clamped state in which it grips the string in a direction that is perpendicular to the longitudinal direction of the string relative to the clamp portion while restricting movement of the string in the direction that is perpendicular to the longitudinal direction. The clamp portion at the tip of the left arm is also configured to be switchable between an open state in which it does not grip the string, a semi-clamped state in which it grips the string in a direction that is perpendicular to the longitudinal direction of the string relative to the clamp portion while allowing movement of the string in the longitudinal direction relative to the clamp portion, and a fully clamped state in which it grips the string in a direction that is perpendicular to the longitudinal direction of the string relative to the clamp portion while restricting movement of the string in the direction that is perpendicular to the longitudinal direction. In the operation of pulling the right arm out of the right string, before the left end of the string, which is grasped by the clamp at the tip of the right arm, slips out to the right from the portion of the right string that is wrapped around the outer circumference of the right arm, the clamp is set to the half-clamped state and the right arm is moved to the right. After the left end of the string, which is grasped by the clamp at the tip of the right arm, slips out to the right from the portion of the right string that is wrapped around the outer circumference of the right arm, the clamp is switched to the fully clamped state and the right arm is moved further to the right. In the operation of pulling the left arm out of the left string, the left arm is moved to the left with the clamp portion of the left arm gripped by the clamp portion of the left arm until the end of the right string, which is gripped by the clamp portion of the left arm, comes out to the left from the portion of the left string that is wrapped around the outer circumference of the left arm, and after the end of the right string, which is gripped by the clamp portion of the left arm gripped by the clamp portion of the left arm, comes out to the left from the portion of the left string that is wrapped around the outer circumference of the left arm, the clamp portion is switched to the fully clamped state and the left arm is moved further to the left, thereby creating a single knot between the left and right strings, as described in any of configurations 1 to 3.

[0019] With this configuration, by moving the left and right arms with the clamp portions at the tips of the left and right arms in a semi-clamp state that allows movement in the longitudinal direction of the string, it is possible to quickly tie the left and right strings into a single knot while preventing the left and right strings from being overly pulled. After that, by moving the left and right arms with the clamp portions at the tips of the left and right arms in a full-clamp state that prevents movement in the longitudinal direction of the string, the tightness of the single knot can be strengthened.

[0020] [Configuration 5] The right arm left - right movement mechanism includes a right - hand electric motor and a right - hand motion conversion mechanism that converts the rotation of the electric motor into left - right movement of the right arm. The left arm left - right movement mechanism includes a left - hand electric motor and a left - hand motion conversion mechanism that converts the rotation of the electric motor into left - right movement of the left arm. In the operation of pulling out the string from the right side of the right arm and the operation of pulling out the string from the left side of the left arm, when the right arm moves to the right and pulls the left string to the right, and at the same time the left arm moves to the left and pulls the right string to the left, the string tying device according to Configuration 4, in which the right - hand electric motor and the left - hand electric motor are torque - controlled so that the force with which the right arm pulls the left string and the force with which the left arm pulls the right string are the same magnitude.

[0021] This configuration prevents the single knot from being off-center to one side in the left-right direction, instead of being exactly midway between the roots of the left and right strings. In other words, when the right arm, which grasps the left string, and the left arm, which grasps the right string, are moved in the left-right direction to form a knot, the shape of the knot portion of the left and right strings may not be symmetrical, resulting in a relatively straight side and a side that wraps around the straight side. In this case, instead of torque-controlling the right electric motor for moving the right arm and the left electric motor for moving the left arm, it is also possible to control the position so that the amount of movement of the left and right arms is the same. However, if this is done, the wrap-around side of the knot portion of the left and right strings may be pulled too much more than the straight side, and as a result, the position of the knot may be off-center to one side in the left-right direction, instead of being exactly midway between the roots of the left and right strings. In contrast, by controlling the torque of the electric motor on the right and the electric motor on the left, the same force is applied to both the wrapped side and the straight side of the knot-forming portion of the left and right strings. This prevents the wrapped side from being pulled too much more than the straight side, and as a result, it prevents the single knot from shifting to one side in the left-right direction from the exact midpoint between the roots of the left and right strings.

[0022] [Composition 6] The clamp portion at the tip of the right arm is configured to be switchable between an open state in which it does not grip the string and a fully clamped state in which it grips the string in such a way that it restricts both the longitudinal movement of the string relative to the clamp portion and the movement in a direction intersecting the longitudinal direction. The clamp portion at the tip of the left arm is also configured to be switchable between an open state in which it does not grip the string and a fully clamped state in which it grips the string in such a way that it restricts both the longitudinal movement of the string relative to the clamp portion and the movement in a direction intersecting the longitudinal direction. A string-tying device according to any one of configurations 1 to 3, wherein in the operation of pulling the right arm out of the string on the right side, the clamp portion at the tip of the right arm is fully clamped and pulled out to the right from the portion of the right string that is wrapped around the outer circumference of the right arm, and in the operation of pulling the left arm out of the string on the left side, the clamp portion at the tip of the left arm is fully clamped and pulled out to the left from the portion of the left string that is wrapped around the outer circumference of the left arm, thereby tying a bow knot with the left and right strings.

[0023] With this configuration, the portion of the string grasped by the clamp at the tip of the left and right arms can be used as a loop to form a bow knot.

[0024] [Composition 7] The aforementioned strings on the left and right are flat, flat strings. The clamp portion at the tip of the right arm is configured to grasp the right side of the flat cord in a orientation where the thickness direction of the cord is in the left-right direction. The string tying device according to configuration 6, wherein the clamp portion at the tip of the left arm is configured to grasp the left string in a orientation where the thickness direction of the flat string is in the left-right direction.

[0025] With this configuration, the clamps at the ends of the left and right arms grip the flat cords in a orientation where the thickness of the cord is in the left-right direction. This results in a neatly shaped loop for the bowknot, creating an aesthetically pleasing bowknot.

[0026] [Structure 8] Left and right tightening pieces extending in the front-to-back direction, A tightening piece forward / backward movement device that moves the left and right tightening pieces together in the forward / backward direction, The device further includes a left-right tightening piece moving device that moves the left and right tightening pieces in opposite directions in the left-right direction, The string-tying device according to configuration 6, wherein after tying the left and right strings in a bow, the left and right tightening pieces are moved in the front-rear direction by the tightening piece front-rear moving device to insert the left and right tightening pieces under the bow knot, and then the left and right tightening pieces are opened to the left and right by the tightening piece left-right moving device to tighten the bow knot.

[0027] By adopting this configuration, it is possible to tighten the bow knot without shortening the straight portion of the cord extending from the knot, resulting in a more aesthetically pleasing bow knot. In other words, a common method for tightening a bow knot is to pull the loops of the bow knot tightly to the left and right. However, this method shortens the straight portion of the cord extending from the bow knot, resulting in an unattractive bow knot. In contrast, by inserting the tightening pieces on both sides under the bow knot and then opening these pieces to the left and right to tighten the bow knot, it is possible to tighten the bow knot without shortening the straight portion of the cord extending from the knot, resulting in a more aesthetically pleasing bow knot.

[0028] [Composition 9] The knot-tying device according to configuration 8, wherein when tightening the bow knot by opening the left and right tightening pieces to the left and right, the tightening is performed while keeping both the clamp portion at the tip of the right arm and the clamp portion at the tip of the left arm in the fully clamped state.

[0029] With this configuration, when tightening a bow knot, the clamps at the ends of the left and right arms grip the loops of the bow knot, so the size of the loops of the bow knot is less likely to change as it is tightened, and the size of the left and right loops of the bow knot is more likely to be uniform. As a result, it is possible to form a visually appealing bow knot.

[0030] Furthermore, this invention also provides the following method for tying knots, which allows for the secure and reliable joining of the left and right strings without failure. [Configuration 10] A method of tying knots, which involves tying together the left and right strings extending from an item with a string attached, A right-side zipper and a left-side zipper are positioned separately to the left and right above the aforementioned stringed article, The right arm and the left arm are provided below the right chuck and the left chuck, extending in the left-right direction, and each arm has a clamp portion at its tip for gripping a string. A right-side chuck forward / backward movement mechanism for moving the right-side chuck in the forward / backward direction, A left chuck forward and backward movement mechanism for moving the left chuck in the forward and backward direction, A right arm forward / backward movement mechanism for moving the right arm in the forward / backward direction, A left arm forward / backward movement mechanism for moving the left arm in the forward / backward direction, A right arm left-right movement mechanism for moving the right arm in the left-right direction, Using a left arm left-right movement mechanism that moves the left arm in the left-right direction, With the right string gripped by the right chuck, the right arm forward / backward movement mechanism moves the right arm to one side in the forward / backward direction, and the right chuck movement mechanism moves the right chuck to the other side in the forward / backward direction, thereby performing the winding operation of the right string onto the right arm, so that the right string is wrapped around the outer circumference of the right arm from one side in the forward / backward direction. With the left string gripped by the left chuck, the left arm forward / backward movement mechanism moves the left arm to the other side in the forward / backward direction, and the left chuck forward / backward movement mechanism moves the left chuck to one side in the forward / backward direction, thereby performing the winding operation of the left string onto the left arm, so that the left string is wrapped around the outer circumference of the left arm from the other side in the forward / backward direction. After the winding operation of the right string onto the right arm and the winding operation of the left string onto the left arm, the right arm left-right movement mechanism moves the right arm to the left, and the clamp portion at the tip of the right arm grips the portion of the left string that is stretched between the left arm and the left chuck, thereby clamping the left string with the right arm, and the left arm left-right movement mechanism moves the left arm to the right, and the clamp portion at the tip of the left arm grips the portion of the right string that is stretched between the right arm and the right chuck, thereby clamping the right string with the left arm, A method of tying knots by simultaneously performing the following actions: clamping the left string with the right arm and clamping the right string with the left arm; moving the right arm to the right using the right arm left-right movement mechanism while the clamp portion at the tip of the right arm is grasping the left string; and simultaneously pulling the right arm out of the portion of the right string that is wrapped around the outer circumference of the right arm; and moving the left arm to the left using the left arm left-right movement mechanism while the clamp portion at the tip of the left arm is grasping the right string; and pulling the left arm out of the portion of the left string that is wrapped around the outer circumference of the left arm. [Effects of the Invention]

[0031] In this knot-tying device, when wrapping the right knot around the right arm, the right arm is moved to one side in the front-to-back direction, and the right chuck is moved to the other side in the front-to-back direction. This allows the right knot to be deeply wrapped around the outer circumference of the right arm from one side in the front-to-back direction, stabilizing the position of the right knot. Similarly, when wrapping the left knot around the left arm, the left arm is moved to the other side in the front-to-back direction, and the left chuck is moved to one side in the front-to-back direction. This allows the left knot to be deeply wrapped around the outer circumference of the left arm from the other side in the front-to-back direction, stabilizing the position of the left knot. Therefore, the operation of gripping the portion of the left knot that is stretched between the left arm and the left chuck with the clamp at the tip of the right arm, and the operation of gripping the portion of the right knot that is stretched between the right arm and the right chuck with the clamp at the tip of the left arm, are less likely to fail, making it possible to stably tie the left and right knots together. [Brief explanation of the drawing]

[0032] [Figure 1] Plan view of a knot-tying device according to an embodiment of this invention. [Figure 2] Right side view of the knot-tying device in Figure 1. [Figure 3] Plan view of the upper portion of the folded-over section, primary knot, and secondary knot shown in Figure 1. [Figure 4] Cross-sectional view along line IV-IV in Figure 2 [Figure 5] Cross-sectional view along line VV in Figure 2 [Figure 6] Cross-sectional view along the line VI-VI in Figure 2 [Figure 7] Enlarged view of the vicinity of the right arm in Figure 6. [Figure 8] Figure 7 shows an enlarged cross-sectional view of the clamp at the tip of the right arm. [Figure 9] Figure 8 is an enlarged cross-sectional view showing the clamp section in a fully open state. [Figure 10] Cross-sectional view along line XX in Figure 2 [Figure 11] Enlarged view of the vicinity of the right arm in Figure 10. [Figure 12]Figure 11 shows an enlarged cross-sectional view of the clamp at the tip of the right arm. [Figure 13] Figure 12 is an enlarged cross-sectional view showing the clamp section in the closed position. [Figure 14] Figure 5 shows the state in which the opening of a drawstring bag is sandwiched between the left and right pairs of folding plates. [Figure 15] Enlarged cross-sectional view along line XV-XV in Figure 14 [Figure 16] Figure 14 shows the left and right folding plates moved in opposite directions in the left-right direction. [Figure 17] Figure 16 shows the state in which the opening of a drawstring bag is folded by rotating and lowering the left and right folding plates. [Figure 18] Figure 17 shows a view from above of the vicinity of the bag with a string attached. [Figure 19] Enlarged cross-sectional view along line XIX-XIX in Figure 18 [Figure 20] Figure 17 shows the left and right folding plates removed from the folded bag opening by moving them in opposite directions. [Figure 21] Figure 20 shows the bag holder lowered, pushing the center of the bag opening downwards in the left-right direction. [Figure 22] Figure 21 shows the left and right first cord transfer chucks rotated to the upright position. [Figure 23] Figure 22 shows the left and right first cord transfer chucks gripping the cords on both sides, and the bag holder in the raised position. [Figure 24] Figure 23 shows the state of the drawstring bag immediately after it has been moved from the folded opening to the primary knot. [Figure 25] Figure 24 shows the left and right chucks descending to grip the left and right strings, the claws of the left and right first string transfer chucks releasing the left and right strings, and then rotating and collapsing. [Figure 26] Figure 25 shows the left and right zippers rising while gripping the left and right strings, and the left and right arms moving in the left-right direction so that they move closer to each other, resulting in the left and right arms overlapping with the left and right strings in the front-to-back direction. [Figure 27] Figure 26 shows the left and right arms and their vicinity, viewed from above. [Figure 28] Figure 27 shows the left and right arms in a state where they have been translated in opposite directions in the front-to-back direction. [Figure 29] Figure 28 shows a state in which the left and right chucks rotate in opposite directions in the front-to-back direction, and the left and right arms move in the left-to-right direction so that they move closer to each other. [Figure 30] Figure 29 shows a view from the rear of the arms tilted so that the tips of the arms rise, with the clamps at the tips of the arms open. [Figure 31] Figure 30 shows the left and right arms moving in the left-right direction, illustrating the state in which the string is stored in the clamps at the ends of the left and right arms. [Figure 32] Figure 31 shows the clamps at the ends of the left and right arms switching from an open state to a semi-clamped state, gripping the left and right strings, while the left and right chucks release the left and right strings. [Figure 33] Figure 32 shows the left and right arms in a state where they have moved from a tilted position to a horizontal position. [Figure 34] Figure 33 shows a view from above of the vicinity of the left and right arms. [Figure 35] Figure 33 shows a state where the clamps at the ends of the left and right arms are in a semi-clamped state, while the left and right arms move in opposite directions. [Figure 36] Figure 35 shows the clamping parts at the ends of the left and right arms switching to a fully clamped state, then moving the left and right arms in opposite directions, and finally rotating the left and right second cord transfer chucks to raise them upright. [Figure 37] Figure 36 shows the left and right second cord transfer chucks gripping the cords on both sides, and then the clamps at the ends of the left and right arms are released. [Figure 38] Figure 37 shows a drawstring bag moving from the primary knot to the secondary knot, and then the right and left zippers of the secondary knot descend to grip the drawstrings on both sides. [Figure 39] Figure 38 shows the left and right zippers rising while gripping the left and right strings, and the left and right arms moving in the left-right direction so that they move closer to each other, resulting in the left and right arms overlapping with the left and right strings in the front-to-back direction. [Figure 40] Figure 39 shows the left and right arms and their vicinity, viewed from above. [Figure 41] Figure 40 shows the left and right arms in a state where they have been translated in opposite directions in the front-to-back direction. [Figure 42] Figure 41 shows a state in which the left and right chucks rotate in opposite directions in the front-to-back direction, and the left and right arms move in the left-to-right direction so that they move closer to each other. [Figure 43] Figure 42 shows a view from the rear of the right arm in a state where the tip of the right arm is tilted upward. [Figure 44] Figure 43 shows the right arm moving to the left, with the left string caught on the clamp at the tip of the right arm. [Figure 45] Figure 44 shows the left arm tilted so that the left arm's tip rises as the right arm returns from its tilted position to a horizontal position, causing the left string to engage with the clamp at the tip of the right arm. [Figure 46] Figure 45 shows the left arm moving to the right, with the right string caught on the clamp at the tip of the left arm. [Figure 47] Figure 46 shows the left and right arms moving in opposite directions, resulting in the right-hand string becoming inserted into the clamp at the tip of the left arm. [Figure 48] Figure 47 shows the state where the clamps at the ends of the left and right arms are fully clamped and gripping the left and right strings. [Figure 49] Figure 48 shows the left and right arms and their vicinity, viewed from above. [Figure 50] Figure 49 shows the state where the left and right chucks release the string, and then the left and right arms move in opposite directions while the clamps at the ends of the left and right arms remain fully clamped. [Figure 51]Figure 50 shows the left and right arms and their vicinity as viewed from the rear. [Figure 52] Figure 51 shows a view from above of the left and right tightening pieces inserted below the bow knot. [Figure 53] Figure 52 shows the left and right tightening pieces raised and in contact with the underside of the bow knot, as viewed from the rear. [Figure 54] Figure 53 shows how the left and right tightening pieces move in opposite directions to the left and right, pushing apart the bases of the left and right strings to tighten the bow knot. [Figure 55] Figure 54 shows the state in which the left and right tightening pieces and the clamping parts at the ends of the left and right arms are retracted. [Figure 56] Figure 55 shows a bag with a bow tied in a bow, viewed from the rear. [Figure 57] Figure 56 shows a bag with a string attached, viewed from above. [Modes for carrying out the invention]

[0033] Figure 1 shows a string-tying device according to an embodiment of the present invention. This string-tying device includes a bag conveying device 2 for conveying a string-attached bag 1, and a bag supply section 3, a mouth-folding section 4, a primary tying section 5, a secondary tying section 6, and a bag discharge section 7, which are arranged in order from the rear (bottom in the figure) to the front (top in the figure) in the direction of conveyance of the string-attached bag 1 by the bag conveying device 2.

[0034] As shown in Figure 4, the drawstring bag 1 has a bottomed cylindrical bag body 8 with an open top and a closed bottom, and a drawstring 9 (closing drawstring) that closes the opening 8a at the top of the bag body 8. The bag body 8 is, for example, a kraft bag made of kraft paper. The bag body 8 is pre-filled with contents (for example, grains such as rice and wheat). The drawstring 9 is fixed to the opening 8a at the top of the bag body 8 by the bases of the drawstrings on both sides, so that they extend to the left and right from the opening 8a. The drawstring 9 is a flat paper string with a flat cross-sectional shape (for example, a paper band made by laminating twisted paper strings in one direction perpendicular to the longitudinal direction).

[0035] As shown in Figure 1, the bag conveying device 2 includes a floor member 10 extending in the front-rear direction (up-down direction in the figure), left and right side frames 11 extending in the front-rear direction and arranged parallel to both the left and right sides of the floor member 10, a side frame left-right movement mechanism 12 that moves the left and right side frames 11 in opposite directions between a conveying position where the distance between the side frames 11 in the left-right direction is narrowed (position shown by the solid line in Figure 10) and a retracted position where the distance between the side frames 11 in the left-right direction is widened (position shown by the dashed line in Figure 10), and a side frame front-rear movement mechanism 13 (see Figure 2) that moves the left and right side frames 11 together in the front-rear direction between a retracted position (position shown by the solid line in Figures 1 and 2) and an advanced position (position shown by the dashed line in Figures 1 and 2).

[0036] As shown in Figure 1, the side frame left-right movement mechanism 12 consists of a guide member 14 that supports the left and right side frames 11 so that they can move in the left-right direction, and an actuator 15 that moves the left and right side frames 11 in the left-right direction. Similarly, the side frame front-rear movement mechanism 13 consists of a guide member 16 that supports the left and right side frames 11 so that they can move in the front-rear direction, and an actuator 17 (see Figure 2) that moves the left and right side frames 11 in the front-rear direction. The actuators 15 and 17 are, for example, air cylinders that expand and contract by air pressure.

[0037] The left and right side frames 11 are provided with back plates 18, 19, 20, and 21 that contact the drawstring bags 1 at the bag supply section 3, the opening fold section 4, the primary knot section 5, and the secondary knot section 6 from the rear (bottom in the diagram). The left and right side frames 11 are also provided with front plates 22, 23, and 24 that contact the drawstring bags 1 at the bag supply section 3, the opening fold section 4, and the primary knot section 5 from the front (top in the diagram). The back plates 18, 19, 20, and 21 and the front plates 22, 23, and 24 are fixed to the side frames 11 so as to move together with the side frames 11.

[0038] The left and right side frames 11 are fitted with left and right first string transfer zippers 25, which transfer the left and right strings 9 of the stringed bag 1 from the opening fold 4 to the primary knot 5 when the stringed bag 1 is moved from the opening fold 4 to the primary knot 5, and left and right second string transfer zippers 26, which transfer the left and right strings 9 of the stringed bag 1 from the primary knot 5 to the secondary knot 6 when the stringed bag 1 is moved from the primary knot 5 to the secondary knot 6.

[0039] As shown in Figures 1 and 2, the first string transfer chuck 25 is attached to the folded portion 4 of the side frame 11. Also, as shown in Figure 2, a rotary actuator 27 is attached to the side frame 11 that rotates the first string transfer chuck 25 between a tilted position where it is bent forward (to the right in the figure) and an upright position where it is raised upward. The first string transfer chuck 25 has a claw portion for gripping the string 9 at the end furthest from the rotation center of the rotary actuator 27.

[0040] Similarly, as shown in Figures 1 and 2, the second string transfer chuck 26 is attached to the primary knot 5 of the side frame 11. Also, as shown in Figure 2, a rotary actuator 30 is attached to the side frame 11 that rotates the second string transfer chuck 26 between a tilted position where it is bent forward (to the right in the figure) and an upright position where it is raised upward. The second string transfer chuck 26 has a claw portion for gripping the string 9 at the end furthest from the rotation center of the rotary actuator 30.

[0041] The drawstring bag 1 is supported by the floor member 10 so as to be movable in the front-rear direction between the bag supply section 3 and the bag discharge section 7. In this case, the floor member 10 is a flat plate-shaped member with a flat top surface that slidably supports the lower surface of the drawstring bag 1.

[0042] As shown in Figures 1 and 2, a pair of string guide bars 32 extending in the front-to-back direction are provided on both the left and right sides above the floor member 10. The string guide bars 32 are fixed members fixed to a fixed frame (not shown). As shown in Figure 1, the left and right string guide bars 32 are formed such that the distance between them in the left-to-right direction gradually narrows from the opening fold portion 4 towards the primary knot portion 5, they extend parallel at the primary knot portion 5, and the distance between them in the left-to-right direction widens from the primary knot portion 5 towards the secondary knot portion 6.

[0043] The bag conveying device 2 moves the stringed bags 1 as follows. First, the actuator 17 shown in Figure 2 drives the left and right side frames 11 shown in Figure 1 forward from the retracted position (position shown by the solid line in the figure) to the forward position (position shown by the dashed line in the figure). As a result, the stringed bags 1 located in the bag supply section 3, the opening fold section 4, the primary tying section 5, and the secondary tying section 6 are pressed against the back plates 18, 19, 20, and 21 and move forward along the upper surface of the floor member 10, moving to the adjacent opening fold section 4, the primary tying section 5, the secondary tying section 6, and the bag discharge section 7 on the downstream side, respectively (feeding operation). Next, the actuator 15 of the side frame left / right movement mechanism 12 is driven to move the left and right side frames 11 from the transport position (indicated by the solid line in Figure 10) to the retracted position (indicated by the dashed line in Figure 10) so that the distance between them in the left-right direction increases. Subsequently, the actuator 17 shown in Figure 2 is driven to move the left and right side frames 11 shown in Figure 1 backward (downward in the figure). After that, the actuator 15 is driven to move the left and right side frames 11 from the retracted position (indicated by the dashed line in Figure 10) back to the transport position (indicated by the solid line in Figure 10) so that the distance between them in the left-right direction decreases (return operation). As a result, the left and right side frames 11 return to the position shown in Figure 1, but the bags 1 with strings attached to the bag supply section 3, the opening folding section 4, the primary tying section 5, and the secondary tying section 6 move to their respective downstream sections. Subsequently, by alternately repeating the above-described feeding and returning operations, the bag conveying device 2 sequentially moves the stringed bags 1 supplied to the bag supply unit 3 toward the bag discharge unit 7, stopping at each of the opening folding section 4, the primary knotting section 5, and the secondary knotting section 6.

[0044] As shown in Figures 3 and 5, the opening fold section 4 includes a pair of left and right opening fold plates 33, an opening and closing mechanism 34 for opening and closing each pair of opening fold plates 33, a rotation and lifting mechanism 35 for raising and lowering each pair of opening fold plates 33 while rotating them around their respective axes in the left-right direction, and a left-right movement mechanism (not shown) for moving each pair of opening fold plates 33 in opposite directions in the left-right direction. The opening fold section 4 is also provided with a bag retainer 36 that moves up and down between a raised position (shown in Figure 5) that is above the drawstring bag 1 and a lowered position (shown in Figure 21) that pushes the left-right center of the upper end of the drawstring bag 1 downward.

[0045] As shown in Figure 6, the primary tying section 5 includes a right zipper 40 and a left zipper 41 positioned separately to the left and right above the bag with string 1, a right swivel actuator 42 and a left swivel actuator 43 that move the right zipper 40 and the left zipper 41 in the front-rear direction (perpendicular to the plane of the paper in the figure), a zipper lifting mechanism 44 that moves the right zipper 40 and the left zipper 41 together in the up-down direction, a right arm 45 and a left arm 46 that are provided below the right zipper 40 and the left zipper 41 so as to extend in the left-right direction, a clamp opening and closing mechanism 48 that opens and closes a clamp section 47 provided at the tip of the right arm 45 and the left arm 46, and an arm tilting mechanism 49 that tilts the right arm 45 and the left arm 46.

[0046] The right-side chuck 40 has a pair of opposing fingers 50 (see Figure 30) for gripping the string 9, and a finger drive unit 51 for opening and closing the pair of fingers 50. The pair of fingers 50 are provided to extend downward from the finger drive unit 51. The left-side chuck 41 is configured similarly to the right-side chuck 40.

[0047] As shown in Figure 3, a right-hand swivel bracket 53 is attached to the right-hand swivel actuator 42 so as to rotate integrally with the right-hand swivel shaft 52, which is the drive shaft of the right-hand swivel actuator 42, and a right-hand chuck 40 is attached to the end of the right-hand swivel bracket 53 that is furthest from the right-hand swivel shaft 52. Similarly, a left-hand swivel bracket 55 is attached to the left-hand swivel actuator 43 so as to rotate integrally with the left-hand swivel shaft 54, which is the drive shaft of the left-hand swivel actuator 43, and a left-hand chuck 41 is attached to the end of the left-hand swivel bracket 55 that is furthest from the left-hand swivel shaft 54.

[0048] The right rotation axis 52 of the right rotation actuator 42 and the left rotation axis 54 of the left rotation actuator 43 are arranged side by side, and the distance between the centers of the right rotation axis 52 and the left rotation axis 54 is set to be the same as or greater than the distance between the bases of the left and right strings 9 shown in Figure 6 (i.e., the inner width of the left and right string guide bars 32).

[0049] As shown by the arrows in Figure 3, the right-side pivot actuator 42 is used to pivot the right-side chuck 40 90° backward (downward in the figure) from a position aligned to the right of the right pivot axis 52 when viewed from above, while the left-side pivot actuator 43 is used to pivot the left-side chuck 41 90° forward (upward in the figure) from a position aligned to the left of the left pivot axis 54 when viewed from above. Here, the right-side pivot actuator 42 and the left-side pivot actuator 43 constitute a chuck forward and backward movement mechanism that moves the right-side chuck 40 and the left-side chuck 41 in opposite directions in the forward and backward direction.

[0050] As shown in Figure 3, the right arm 45 and the left arm 46 are positioned perpendicular to the front-to-back direction (up-to-down direction in the figure) when viewed from above. The right arm 45 is positioned rearward (downward in the figure) relative to the center position of the right chuck 40 when the right chuck 40 is aligned to the right of the right pivot axis 52 (i.e., before the right chuck 40 pivots to the rearward (downward in the figure) direction). On the other hand, the left arm 46 is positioned frontward (upward in the figure) relative to the center position of the left chuck 41 when the left chuck 41 is aligned to the left of the left pivot axis 54 (i.e., before the left chuck 41 pivots to the frontward (upward in the figure) direction). Thus, the right arm 45 and the left arm 46 are positioned offset to the side in the direction of movement of the right chuck 40 and the left chuck 41, with respect to the respective center positions of the right chuck 40 and the left chuck 41 before they move in opposite directions in the front-rear direction.

[0051] As shown in Figure 6, when viewed from the front-to-back direction, the right arm 45 and the left arm 46 are provided to extend in the left-to-right direction. The right arm 45 and its surrounding area, and the left arm 46 and its surrounding area, have the same symmetrical configuration. Therefore, the configuration of the right arm 45 and its surrounding area will be described below, and the configuration of the left arm 46 and its surrounding area will be given the same reference numerals and its description will be omitted.

[0052] As shown in Figure 7, the right arm 45 is attached to a tilting bracket 57 which is supported so as to be tiltable around a tilting axis 56. The right arm 45 is attached so as to extend to the left from the tilting bracket 57 in a cantilevered manner, with the base end (right end) of the right arm 45 fixed to the tilting bracket 57. A tilting actuator 58 is attached to the tilting bracket 57 to tilt the tilting bracket 57. In the figure, the tilting actuator 58 is an air cylinder with one end rotatably connected to a support frame 59 and the other end rotatably connected to the tilting bracket 57. The tilting axis 56 is attached to a support bracket 60 which is fixed to the lower surface of the support frame 59.

[0053] The right arm 45 is tiltable between a horizontal position where the tip of the right arm 45 faces horizontally (the position shown by the solid line in Figure 7) and a tilted position where the tip of the right arm 45 faces diagonally upward (the position shown by the dashed line in Figure 7), by the extension and retraction of the tilt actuator 58. Here, the tilt axis 56, the tilt bracket 57, and the tilt actuator 58 form an arm tilting mechanism 49 that tilts the right arm 45.

[0054] As shown in Figures 8 and 9, the clamp portion 47 at the tip of the right arm 45 is composed of a pair of upper and lower clamping claws 61 extending to the left from the tip of the right arm 45. Each clamping claw 61 is pivotably supported on a pin 62 provided at the base of the clamping claw 61, and the pivoting of each clamping claw 61 causes the pair of upper and lower clamping claws 61 to open and close, allowing them to grasp the string 9 (see Figure 6). In addition, one of the upper and lower clamping claws 61 has a projection 63 at its tip that protrudes toward the other clamping claw 61, and the other clamping claw 61 has a recess 64 that accommodates the projection 63. The projection 63 is formed in a cylindrical shape that extends in the vertical direction.

[0055] The clamp opening and closing mechanism 48 includes pinions 65 formed at the base ends of a pair of upper and lower clamp claws 61, a clamp operating rod 67 with a rack 66 formed at its tip that engages with both pinions 65, and a clamp operating actuator 68 (see Figure 7) that moves the clamp operating rod 67 in the longitudinal direction. The clamp operating rod 67 is mounted on the right arm 45 so as to be movable in the longitudinal direction of the right arm 45. As shown in Figure 7, the clamp operating rod 67 has a portion that protrudes from the base end of the right arm 45, and the clamp operating actuator 68 is connected to this protruding portion. The clamp operating actuator 68 is attached to the tilting bracket 57 so as to tilt integrally with the tilting bracket 57.

[0056] The clamping actuator 68 shown in Figure 7 is configured to allow the clamping rod 67 to be selectively moved to three predetermined positions. Specifically, the clamping actuator 68 is configured to allow the clamping rod 67 to be selectively moved to three positions: a fully clamped position where the pair of clamping claws 61 are completely closed, as shown in Figure 8; an open position where the pair of clamping claws 61 are completely open, as shown in Figure 9; and a half-clamped position where the pair of clamping claws 61 are partially closed, as shown in Figure 35. As a result, the clamping section 47 can switch between an open state where it does not grip the string 9 (as shown in Figure 8), a fully clamped state where it grips the string 9 in a way that restricts both its longitudinal movement and its movement in a direction intersecting the longitudinal direction relative to the clamping section 47 (as shown in Figure 9), and a half-clamped state where it grips the string 9 in a way that restricts its movement in a direction intersecting the longitudinal direction relative to the clamping section 47 while allowing its longitudinal movement relative to the clamping section 47 (as shown in Figure 35). In this case, the semi-clamped state is a state in which the protrusion 63 prevents the string 9 from falling out between the pair of clamping claws 61.

[0057] As a clamp operating actuator 68 that can selectively move the clamp operating rod 67 to three predetermined positions, it is possible to use a combination of an electric motor and a motion conversion mechanism (such as a lead screw mechanism) that converts the rotation of the electric motor into linear movement of the clamp operating rod 67. However, it is more cost-effective to use a configuration in which two air cylinders that extend and retract with a short stroke (for example, a stroke of 10 mm or less) are arranged in series, and the clamp operating rod 67 is moved by selectively extending and retracting these two air cylinders.

[0058] The right support frame 59 shown in Figure 6 is supported by the right arm left-right movement mechanism 69. The right arm left-right movement mechanism 69 employs a configuration that includes an electric motor (not shown) and a motion conversion mechanism (for example, a ball screw mechanism with the left-right direction as the axis) that converts the rotation of the electric motor into left-right movement of the right support frame 59. The right arm left-right movement mechanism 69 moves the right arm 45, the right clamp opening / closing mechanism 48, and the right arm tilting mechanism 49, all supported by the right support frame 59, in a linear fashion in the left-right direction.

[0059] Furthermore, the right arm left-right movement mechanism 69 is supported by the right arm front-back movement mechanism (not shown). The right arm front-back movement mechanism moves the right support frame 59 linearly in the front-back direction (perpendicular to the plane of the paper in the figure), thereby moving the right arm 45, the right clamp opening / closing mechanism 48, and the right arm tilting mechanism 49, all supported by the right support frame 59, together in the front-back direction.

[0060] Similarly, the left support frame 59 is supported by the left arm left-right movement mechanism 69, and the left arm left-right movement mechanism 69 is supported by the left arm front-rear movement mechanism (not shown). The left arm left-right movement mechanism 69 and the left arm front-rear movement mechanism are configured similarly to the right arm left-right movement mechanism 69 and the right arm front-rear movement mechanism.

[0061] As shown in Figure 10, the secondary knot section 6 includes a right-side zipper 70 and a left-side zipper 71 positioned separately to the left and right above the bag with the string 1, a right-side swivel actuator 72 and a left-side swivel actuator 73 that move the right-side zipper 70 and the left-side zipper 71 in the front-rear direction (perpendicular to the plane of the paper in the figure), a zipper lifting mechanism 74 that moves the right-side zipper 70 and the left-side zipper 71 together in the up-down direction, a right-side arm 75 and a left-side arm 76 that are provided below the right-side zipper 70 and the left-side zipper 71 so as to extend in the left-right direction, a clamp opening and closing mechanism 78 that opens and closes a clamp section 77 provided at the tip of the right-side arm 75 and the left-side arm 76, and an arm tilting mechanism 79 that tilts the right-side arm 75 and the left-side arm 76.

[0062] The right-side chuck 70 has a pair of opposing fingers 80 (see Figure 43) for gripping the string 9, and a finger drive unit 81 for opening and closing the pair of fingers 80. The pair of fingers 80 are provided to extend downward from the finger drive unit 81. The left-side chuck 71 is configured similarly to the right-side chuck 70.

[0063] As shown in Figure 3, a right-hand swivel bracket 83 is attached to the right-hand swivel actuator 72 so as to rotate integrally with the right-hand swivel shaft 82, which is the drive shaft of the right-hand swivel actuator 72, and a right-hand chuck 70 is attached to the end of the right-hand swivel bracket 83 that is furthest from the right-hand swivel shaft 82. Similarly, a left-hand swivel bracket 85 is attached to the left-hand swivel actuator 73 so as to rotate integrally with the left-hand swivel shaft 84, which is the drive shaft of the left-hand swivel actuator 73, and a left-hand chuck 71 is attached to the end of the left-hand swivel bracket 85 that is furthest from the left-hand swivel shaft 84.

[0064] The right rotation axis 82 of the right rotation actuator 72 and the left rotation axis 84 of the left rotation actuator 73 are arranged side by side. The distance between the centers of the right rotation axis 82 and the left rotation axis 84 is set to be the same as the distance between the centers of the right rotation axis 52 and the left rotation axis 54 of the primary connection section 5.

[0065] As shown by the arrows in Figure 3, the right-side pivot actuator 72 is used to pivot the right-side chuck 70 90° forward (upward in the figure) from a position aligned to the right of the right pivot axis 82 when viewed from above, while the left-side pivot actuator 73 is used to pivot the left-side chuck 71 90° backward (downward in the figure) from a position aligned to the left of the left pivot axis 84 when viewed from above. Here, the right-side pivot actuator 72 and the left-side pivot actuator 73 constitute a chuck forward and backward movement mechanism that moves the right-side chuck 70 and the left-side chuck 71 in opposite directions in the forward and backward direction. Furthermore, the direction of movement of the right-side chuck 70 and the left-side chuck 71 in the secondary knotting section 6 is set to be alternating with the direction of movement of the right-side chuck 40 and the left-side chuck 41 in the primary knotting section 5.

[0066] As shown in Figure 3, the right arm 75 and the left arm 76 are positioned perpendicular to the front-to-back direction (up-to-down direction in the figure) when viewed from above. The right arm 75 is positioned forward (upper in the figure) relative to the center position of the right chuck 70 when the right chuck 70 is aligned to the right of the right pivot axis 82 (i.e., before the right chuck 70 pivots forward (upper in the figure)). On the other hand, the left arm 76 is positioned backward (downward in the figure) relative to the center position of the left chuck 71 when the left chuck 71 is aligned to the left of the left pivot axis 84 (i.e., before the left chuck 71 pivots backward (downward in the figure)). Thus, the right arm 75 and the left arm 76 are positioned offset to the side in the direction of movement of the right chuck 70 and the left chuck 71, with respect to the respective center positions of the right chuck 70 and the left chuck 71 before they move in opposite directions in the front-rear direction.

[0067] As shown in Figure 10, when viewed from the front-to-back direction, the right arm 75 and the left arm 76 are provided to extend in the left-to-right direction. The right arm 75 and its surrounding area, and the left arm 76 and its surrounding area, have the same symmetrical configuration. Therefore, the configuration of the right arm 75 and its surrounding area will be described below, and the configuration of the left arm 76 and its surrounding area will be given the same reference numerals and its description will be omitted.

[0068] As shown in Figure 11, the right arm 75 is attached to a tilting bracket 87 which is supported so as to be tiltable around a tilting axis 86. The right arm 75 is attached so as to extend to the left from the tilting bracket 87 in a cantilevered manner, with the base end (right end) of the right arm 75 fixed to the tilting bracket 87. A tilting actuator 88 is attached to the tilting bracket 87 to tilt the tilting bracket 87. In the figure, the tilting actuator 88 is an air cylinder with one end rotatably connected to a support frame 89 and the other end rotatably connected to the tilting bracket 87. The tilting axis 86 is attached to a support bracket 90 which is fixed to the lower surface of the support frame 89.

[0069] The right arm 75 is capable of tilting between a horizontal position where the tip of the right arm 75 faces horizontally (the position shown by the solid line in Figure 11) and a tilted position where the tip of the right arm 75 faces diagonally upward (the position shown by the dashed line in Figure 11) by the extension and retraction of the tilt actuator 88. Here, the tilt shaft 86, the tilt bracket 87, and the tilt actuator 88 form an arm tilting mechanism 79 that tilts the right arm 75.

[0070] As shown in Figures 12 and 13, the clamp portion 77 at the tip of the right arm 75 is composed of a downward-extending clamp receiving piece 91 provided at the tip of the right arm 75 and a clamp rod 93 having a clamping surface 92 at its tip that contacts the clamp receiving piece 91. The clamp rod 93 is a rod-shaped member assembled to the right arm 75 so as to be movable in the longitudinal direction. The clamp receiving piece 91 is fixed to the right arm 75 so as to receive the tip of the clamp rod 93 when the clamp rod 93 protrudes.

[0071] The clamp receiving piece 91 is formed in a cylindrical shape that extends vertically. The clamping surface 92 at the tip of the clamping rod 93 is formed in a planar shape perpendicular to the longitudinal direction of the right arm 75. A U-shaped gap that opens downward is formed between the clamping surface 92 at the tip of the clamping rod 93 and the clamp receiving piece 91. This clamping section 77 is designed so that by extending the clamping rod 93 toward the clamp receiving piece 91, the gap between the clamping surface 92 at the tip of the clamping rod 93 and the clamp receiving piece 91 is opened and closed, allowing the flat cord 9 (see Figure 13) to be gripped in a orientation where the thickness direction of the cord is in the left-right direction.

[0072] As shown in Figure 11, the clamp opening and closing mechanism 78 has a clamp operating actuator 94 connected to a portion of the clamp rod 93 that protrudes from the base end of the right arm 75. The clamp operating actuator 94 is mounted on the tilting bracket 87 so as to tilt integrally with the tilting bracket 87.

[0073] The clamping actuator 94 shown in Figure 11 is capable of selectively moving the clamp rod 93 to an open position, as shown in Figure 12, where the gap between the clamping surface 92 at the tip of the clamp rod 93 and the clamping receiving piece 91 is opened, and to a fully clamped position, as shown in Figure 13, where the gap between the clamping surface 92 at the tip of the clamp rod 93 and the clamping receiving piece 91 is closed. This allows the clamping portion 77 to switch between an open state (shown in Figure 12) where it does not grip the string 9, and a fully clamped state (shown in Figure 13) where it grips the string 9 in a way that restricts both its movement in the longitudinal direction and its movement in a direction intersecting the longitudinal direction relative to the clamping portion 77. The clamping actuator 94 shown in Figure 11 is, for example, a single air cylinder.

[0074] The right support frame 89 shown in Figure 10 is supported by the right arm left-right movement mechanism 95. The right arm left-right movement mechanism 95 employs a configuration that includes an electric motor (not shown) and a motion conversion mechanism (for example, a ball screw mechanism with the left-right direction as the axis) that converts the rotation of the electric motor into left-right movement of the right support frame 89. The right arm left-right movement mechanism 95 moves the right arm 75, the right clamp opening / closing mechanism 78, and the right arm tilting mechanism 79, all supported by the right support frame 89, in a linear fashion in the left-right direction.

[0075] Furthermore, the right arm left-right movement mechanism 95 is supported by the right arm front-back movement mechanism (not shown). The right arm front-back movement mechanism moves the right support frame 89 linearly in the front-back direction (perpendicular to the plane of the paper in the figure), thereby moving the right arm 75, the right clamp opening / closing mechanism 78, and the right arm tilting mechanism 79, all supported by the right support frame 89, together in the front-back direction.

[0076] Similarly, the left support frame 89 is supported by the left arm left-right movement mechanism 95, and the left arm left-right movement mechanism 95 is supported by the left arm front-rear movement mechanism (not shown). The left arm left-right movement mechanism 95 and the left arm front-rear movement mechanism are configured similarly to the right arm left-right movement mechanism 95 and the right arm front-rear movement mechanism.

[0077] As shown in Figure 1, the secondary knot section 6 includes a pair of left and right tightening pieces 96 extending in the front-rear direction (up and down direction in the figure), a tightening piece front-rear movement device (not shown) that moves the tightening pieces 96 together in the front-rear direction, a tightening piece up-down movement device (not shown) that moves the tightening pieces 96 in the up-down direction (direction perpendicular to the plane of the paper in the figure), and a tightening piece left-right movement device (not shown) that moves the left and right tightening pieces 96 in opposite directions in the left-right direction between a width reduction position (position shown in Figure 53) where the distance between them in the left-right direction is narrowed and a width expansion position (position shown in Figure 54) where the distance between them in the left-right direction is widened.

[0078] This section explains an example of how this knot-tying device works.

[0079] [Bag transfer process from bag supply unit 3 to opening folding unit 4] A bag with a string attached 1 is placed in the bag supply unit 3 shown in Figure 1. Then, the left and right side frames 11 move forward (upwards in the figure) as a single unit, pushing the bag with a string attached 1 against the back plate 18 and moving from the bag supply unit 3 to the opening folding unit 4. Subsequently, the left and right side frames 11 move away from each other in the left-right direction, then move backward (downwards in the figure) as a single unit, and then move closer to each other in the left-right direction. As a result, the left and right side frames 11 return to the positions shown in Figure 1.

[0080] [Folding the opening of the bag] Next, as shown in Figure 3, each pair of folding plates 33 on the left and right sides of the drawstring bag 1 opens, and as shown in Figure 14, the opening 8a of the drawstring bag 1 is sandwiched between the folding plates 33. At this time, as shown in Figure 15, the string-holding groove 37, which extends in the left-right direction and is formed on the surface of the tip of one of the pair of folding plates 33 that sandwich the opening 8a of the bag, accommodates the portion of the string 9 that is attached to the opening 8a of the bag.

[0081] Subsequently, as shown in Figure 16, each pair of left and right folding plates 33 move away from each other in the left-right direction, shortening the clamping length of the bag opening 8a by the folding plates 33. In this state, as shown in Figure 17, the left and right folding plates 33 rotate and descend, wrapping the bag opening 8a around the folding plates 33. As a result, as shown in Figures 18 and 19, the bag opening 8a is folded into a flat cylindrical shape (folded).

[0082] Subsequently, as shown in Figure 20, each pair of folding plates 33 on the left and right move away from each other in the left-right direction, and are extended out to the left and right from the folded bag opening 8a. At this time, the left and right strings 9 are held in the string holding grooves 37 (see Figure 15) at the tips of each pair of folding plates 33 on the left and right. Then, as shown in Figure 21, the bag holder 36 descends, pushing downwards the left-right center of the folded bag opening 8a.

[0083] [Bag transfer process from the folded opening 4 to the primary knot 5] Next, as shown in Figure 22, the left and right first string transfer chucks 25 are raised upward by the drive of the rotary actuator 27. At this time, the portions of the left and right strings 9 that extend from the opening fold plate 33 toward the stringed bag 1 are inserted into the open claws of the left and right first string transfer chucks 25. Subsequently, as shown in Figure 23, the claws of the left and right first string transfer chucks 25 close to grip the left and right strings 9, and the bag retainer 36 rises. At this time, the claws of the left and right first string transfer chucks 25 do not grip the ends of the left and right strings 9, but rather grip the middle portions of the left and right strings 9 closer to the root than the ends.

[0084] Subsequently, as the left and right side frames 11 shown in Figure 23 move forward (towards the back of the paper in the figure), the drawstring bag 1 is pushed by the back plate 19 and moves from the opening fold 4 to the primary knot 5. Also, as the first drawstring transfer zipper 25 moves together with the side frames 11, the left and right drawstrings 9 held by the first drawstring transfer zipper 25 also move from the opening fold 4 to the primary knot 5.

[0085] As shown in Figure 24, when the drawstring bag 1 moves to the primary knot 5, the right-side zipper 40 of the primary knot 5 is located above a position shifted to the left (i.e., towards the base of the drawstring 9) of the portion of the right drawstring 9 that is gripped by the first drawstring transfer zipper 25, and the left-side zipper 41 is located above a position shifted to the right (i.e., towards the base of the drawstring 9) of the portion of the left drawstring 9 that is gripped by the first drawstring transfer zipper 25.

[0086] Subsequently, as shown in Figure 25, the right-side zipper 40 and the left-side zipper 41 descend and grasp the left and right strings 9, respectively. At this time, the right-side zipper 40 and the left-side zipper 41 do not grasp the ends of the left and right strings 9, but rather grasp the middle portion of the strings 9 closer to the root than the ends. In other words, the left and right first string transfer zippers 25 are designed to grasp the middle portion of the left and right strings 9 closer to the root than the ends (the portion corresponding to the straight portion 101 extending from the bow knot 100 shown in Figures 56 and 57), rather than the ends of the left and right strings 9, and to transfer that middle portion to the right-side zipper 40 and the left-side zipper 41.

[0087] Subsequently, the claws of the left and right first string transfer chucks 25 open, releasing the string 9, and the rotary actuator 27 drives the unit forward (towards the back of the page in the diagram).

[0088] [Primary knotting process] Next, as shown in Figure 26, the right chuck 40 and the left chuck 41 rise while gripping the left and right strings 9. Then, as shown by the arrows in Figure 26, the right arm 45 and the left arm 46 move in the left-right direction so that they move closer to each other. As a result, the right arm 45 faces the right string 9 from the rear (front side of the paper in the figure), and the left arm 46 faces the left string 9 from the front (back side of the paper in the figure). Also, as shown in Figure 27, the right arm 45 extends in the left-right direction above the right string guide bar 32 so that it intersects with the right string guide bar 32 when viewed from above, and the left arm 46 also extends in the left-right direction above the left string guide bar 32 so that it intersects with the left string guide bar 32 when viewed from above.

[0089] Next, the following actions—wrapping the right string 9 around the right arm 45 and wrapping the left string 9 around the left arm 46—are performed simultaneously and in sync on both sides.

[0090] <The action of wrapping the string 9 on the right side around the arm 45 on the right side> As shown in Figures 27 and 28, the right arm 45 moves forward (upward in the figures), and then, as shown in Figure 29, the right arm 45 moves to the left, and subsequently, the right chuck 40 rotates 90° backward (downward in the figures) while still gripping the right string 9. As a result, as shown in Figure 29, the right string 9 is wrapped around the outer circumference of the right arm 45 from the front (upward in the figures). At this time, the portion 9a of the right string 9 that is stretched between the right arm 45 and the right chuck 40, as shown in Figures 29 and 30, is extended horizontally or at an angle close to horizontal (specifically, at an angle of less than 30° to the horizontal).

[0091] <The action of wrapping the left string 9 around the left arm 46> As shown in Figures 27 and 28, the left arm 46 moves to the rear (downward in the figures), and then, as shown in Figure 29, the left arm 46 moves to the right, and subsequently, the left chuck 41 rotates 90° forward (upward in the figures) while still gripping the left string 9. As a result, as shown in Figure 29, the left string 9 is wrapped around the outer circumference of the left arm 46 from the rear (downward in the figures). At this time, the portion 9a of the left string 9 that is stretched between the left arm 46 and the left chuck 41, as shown in Figures 29 and 30, is extended horizontally or at an angle close to horizontal (specifically, at an angle of less than 30° to the horizontal).

[0092] Next, the clamping action of the left string 9 by the right arm 45 and the clamping action of the right string 9 by the left arm 46 are performed simultaneously and in sync on both sides.

[0093] <Clamping action of the left string 9 by the right arm 45> As shown in Figure 30, the right arm 45 tilts so that the height of the clamp portion 47 at the tip of the right arm 45 corresponds to the height of the left string 9 held by the left chuck 41. Subsequently, the clamp portion 47 at the tip of the right arm 45 becomes fully open, and the right arm 45 moves to the left in this state. As a result, as shown in Figure 31, the portion 9a of the left string 9 that is stretched between the left arm 46 and the left chuck 41 becomes inserted into the clamp portion 47 at the tip of the right arm 45. Then, as shown in Figure 32, the clamp portion 47 at the tip of the right arm 45 switches to a semi-clamped state and grips the left string 9. After that, the left chuck 41 opens and releases the string 9, and then, as shown in Figure 33, the right arm 45 returns from the tilted position to the horizontal position while the clamp portion 47 at the tip of the right arm 45 remains in a semi-clamped state.

[0094] <Clamping action of the right-side string 9 by the left-side arm 46> As shown in Figure 30, the left arm 46 tilts so that the height of the clamp portion 47 at the tip of the left arm 46 corresponds to the height of the right string 9 held by the right chuck 40. Subsequently, the clamp portion 47 at the tip of the left arm 46 becomes fully open, and the left arm 46 moves to the right in this state. As a result, as shown in Figure 31, the portion 9a of the right string 9 that is stretched between the right arm 45 and the right chuck 40 becomes inserted into the clamp portion 47 at the tip of the left arm 46. Then, as shown in Figure 32, the clamp portion 47 at the tip of the left arm 46 switches to a semi-clamped state and grips the right string 9. After that, the right chuck 40 opens and releases the string 9, and then, as shown in Figure 33, the left arm 46 returns from the tilted position to the horizontal position while the clamp portion 47 at the tip of the left arm 46 remains in a semi-clamped state.

[0095] Next, the pulling motion of the right arm 45 from the right side of the string 9 and the pulling motion of the left arm 46 from the left side of the string 9 are performed simultaneously and in sync on both sides.

[0096] <Pulling action from the right-side string 9 of the right-side arm 45> As shown in Figure 34, while the clamp portion 47 at the tip of the right arm 45 is gripping the left string 9, the right arm 45 is moved to the right, and the right arm 45 is pulled out from the portion of the right string 9 that is wrapped around the outer circumference of the right arm 45. At this time, while the clamp portion 47 at the tip of the right arm 45 is disengaged to the right from the portion of the right string 9 that is wrapped around the outer circumference of the right arm 45, and even after the clamp portion 47 at the tip of the right arm 45 has disengaged to the right from the portion of the right string 9 that is wrapped around the outer circumference of the right arm 45, the clamp portion 47 at the tip of the right arm 45 is moved to the right in a semi-clamped state that allows movement of the string 9 in the longitudinal direction, as shown in Figure 35, until the tip of the left string 9 (see Figure 36) gripped by the clamp portion 47 at the tip of the right arm 45 disengages to the right from the portion of the right string 9 that is wrapped around the outer circumference of the right arm 45. Then, the end of the left string 9 (see Figure 36), which is grasped by the clamp portion 47 at the tip of the right arm 45, slips out to the right from the portion of the right string 9 that is wrapped around the outer circumference of the right arm 45 as shown in Figure 34. After that, as shown in Figure 36, the clamp portion 47 at the tip of the right arm 45 is switched from a half-clamped state to a fully clamped state, and the right arm 45 is moved further to the right in that state.

[0097] <Pulling action from the left side of the left arm 46, using the left string 9> As shown in Figure 34, while the left arm 46 is gripping the right string 9 with the clamp portion 47 at its tip, the left arm 46 is moved to the left, and the left arm 46 is pulled out from the portion of the left string 9 that is wrapped around the outer circumference of the left arm 46. At this time, from the time the clamp portion 47 at the tip of the left arm 46 comes out to the left from the portion of the left string 9 that is wrapped around the outer circumference of the left arm 46, and even after the clamp portion 47 at the tip of the left arm 46 comes out to the left from the portion of the left string 9 that is wrapped around the outer circumference of the left arm 46, the clamp portion 47 at the tip of the left arm 46 is moved to the left with the clamp portion 47 at the tip of the left arm 46 (see Figure 36) still gripped by the clamp portion 47 at the tip of the left arm 46 coming out to the left from the portion of the left string 9 that is wrapped around the outer circumference of the left arm 46, as shown in Figure 35, the left arm 46 is moved to the left with the clamp portion 47 at the tip of the left arm 46 in a semi-clamped state that allows movement of the string 9 in the longitudinal direction. Then, the end of the right string 9 (see Figure 36), which is grasped by the clamp portion 47 at the tip of the left arm 46, slips out to the left from the portion of the left string 9 that is wrapped around the outer circumference of the left arm 46 as shown in Figure 34. After that, as shown in Figure 36, the clamp portion 47 at the tip of the left arm 46 is switched from a half-clamped state to a fully clamped state, and the left arm 46 is moved further to the left in that state.

[0098] When the pulling operation from the right side of the right arm 45 and the pulling operation from the left side of the left arm 46 are performed simultaneously, the left and right strings 9 become tied together in a single knot, as shown in Figure 36.

[0099] Here, the movement of the right arm 45 and the left arm 46 is performed by operating the electric motor of the right arm left-right movement mechanism 69 that supports the right support frame 59, as shown in Figure 6, and the electric motor of the left arm left-right movement mechanism 69 that supports the left support frame 59. Then, as shown in Figure 36, when the clamp portion 47 at the tip of the right arm 45 is fully clamped and the right arm 45 moves to the right, the left string 9 (the part of the left string 9 that extends to the right from the single knot 99) is pulled to the right, and at the same time, when the clamp portion 47 at the tip of the left arm 46 is fully clamped and the left arm 46 moves to the left, the right string 9 (the part of the right string 9 that extends to the left from the single knot 99) is pulled to the left, the electric motors of the right arm left-right movement mechanism 69 and the electric motors of the left arm left-right movement mechanism 69, as shown in Figure 6, are controlled by torque rather than position so that the pulling force on the left and right strings 9 is the same magnitude.

[0100] During the primary knotting process described above, the left and right side frames 11, located at the positions shown by the dashed lines in Figure 1, move away from each other in the left-right direction, then move backward (downward in the figure), and then move closer to each other in the left-right direction, performing a series of parallel movements until they return to the positions shown in Figure 1.

[0101] [Bag transfer process from primary knot 5 to secondary knot 6] In the following explanation, the string 9 extending to the right from the single knot 99 shown in Figure 36 (the string 9 held by the right-side zipper 70 of the secondary knot section 6 shown in Figure 38) will be referred to as the right-side string 9, and the string 9 extending to the left from the single knot 99 (the string 9 held by the left-side zipper 71 of the secondary knot section 6 shown in Figure 38) will be referred to as the left-side string 9. In the above explanation, the string 9 extending to the right from the drawstring bag 1 shown in Figure 4 (the string 9 held by the right-side zipper 40 of the primary knot section 5 shown in Figure 25) will be referred to as the right-side string 9, and the string 9 extending to the left from the drawstring bag 1 (the string 9 held by the left-side zipper 41 of the primary knot section 5 shown in Figure 25) will be referred to as the left-side string 9.

[0102] Next, as shown in Figure 36, the left and right second string transfer chucks 26 are raised upward by the drive of the rotary actuator 30. At this time, the portion of the right string 9 extending from the clamp portion 77 at the tip of the right arm 75 toward the bag with the string is inserted into the open claw of the right second string transfer chuck 26, and the portion of the left string 9 extending from the clamp portion 77 at the tip of the left arm 76 toward the bag with the string is inserted into the open claw of the left second string transfer chuck 26.

[0103] Subsequently, as shown in Figure 37, the claws of the left and right second cord transfer chucks 26 close to grip the left and right cords 9. At this time, the claws of the left and right second cord transfer chucks 26 do not grip the ends of the left and right cords 9, but rather grip the middle portion of the cords 9 closer to the root than the ends. Then, the clamp portion 77 at the tip of the right arm 75 and the clamp portion 77 at the tip of the left arm 76 switch to a fully open state, releasing the cords 9.

[0104] Subsequently, as the left and right side frames 11 shown in Figure 37 move forward (towards the back of the page in the figure), the bag with the strings 1 is pushed by the back plate 20 and moves from the primary knot 5 to the secondary knot 6. Also, as the second string transfer zipper 26 moves together with the side frames 11, the left and right strings 9 held by the second string transfer zipper 26 also move from the primary knot 5 to the secondary knot 6.

[0105] When the drawstring bag 1 moves to the secondary knot 6, the right-side zipper 70 of the secondary knot 6 shown in Figure 38 is located above a position shifted to the left (i.e., towards the base of the string 9) of the portion of the right-side string 9 that is gripped by the second string transfer zipper 26, and the left-side zipper 71 is located above a position shifted to the right (i.e., towards the base of the string 9) of the portion of the left-side string 9 that is gripped by the second string transfer zipper 26.

[0106] Subsequently, as shown by the arrows in Figure 38, the right chuck 70 and the left chuck 71 descend and grip the left and right strings 9, respectively. At this time, the right chuck 70 and the left chuck 71 do not grip the ends of the left and right strings 9, but rather grip the middle portion of the strings 9 closer to the root than the ends. In other words, the left and right second string transfer chucks 26 are designed to grip the middle portion of the left and right strings 9 closer to the root than the ends (the portion corresponding to the straight portion 101 extending from the bow knot 100 shown in Figures 56 and 57), rather than the ends of the left and right strings 9, and to transfer that middle portion to the right chuck 70 and the left chuck 71.

[0107] Subsequently, the claws of the second string transfer chucks 26 on the left and right open, releasing the string 9, and the rotary actuator 30 drives the unit forward (towards the back of the page in the diagram).

[0108] [Second knotting process] Next, as shown in Figure 39, the right chuck 70 and the left chuck 71 rise while gripping the left and right strings 9. Then, as indicated by the arrows in Figure 39, the right arm 75 and the left arm 76 move in the left-right direction so that they move closer to each other. As a result, the right arm 75 faces the right string 9 from the front (towards the back of the page in the figure), and the left arm 76 faces the left string 9 from the rear (towards the front of the page in the figure). Also, as shown in Figure 40, the right arm 75 extends in the left-right direction above the right string guide bar 32 so as to intersect it when viewed from above, and the left arm 76 also extends in the left-right direction above the left string guide bar 32 so as to intersect it when viewed from above.

[0109] Next, the following actions—wrapping the right string 9 around the right arm 75 and wrapping the left string 9 around the left arm 76—are performed simultaneously and in sync on both sides.

[0110] <The action of wrapping the string 9 on the right side around the right arm 75> As shown in Figures 40 and 41, the right arm 75 moves to the rear (downward in the figures), and then, as shown in Figure 42, the right arm 75 moves to the left, and subsequently, the right chuck 70 rotates 90° forward (upward in the figures) while still gripping the right string 9. As a result, as shown in Figure 42, the right string 9 is wrapped around the outer circumference of the right arm 75 from the rear (downward in the figures). At this time, the portion 9a of the right string 9 that is stretched between the right arm 75 and the right chuck 70 as shown in Figure 42 is extended horizontally or at an angle close to horizontal (specifically, at an angle of less than 30° to the horizontal).

[0111] <The action of wrapping the left string 9 around the left arm 76> As shown in Figures 40 and 41, the left arm 76 moves forward (upward in the figures), and then, as shown in Figure 42, the left arm 76 moves to the right, and subsequently, the left chuck 71 rotates 90° backward (downward in the figures) while still gripping the left string 9. As a result, as shown in Figure 42, the left string 9 is wrapped around the outer circumference of the left arm 76 from the front (upward in the figures). At this time, the portion 9a of the left string 9 that is stretched between the left arm 76 and the left chuck 71, as shown in Figure 42, is extended horizontally or at an angle close to horizontal (specifically, at an angle of less than 30° to the horizontal).

[0112] Next, the left string 9 is clamped by the right arm 75, and the right string 9 is clamped by the left arm 76.

[0113] <Clamping action of the left string 9 by the right arm 75> (first half) First, as shown in Figure 43, the right arm 75 tilts so that the height of the clamp portion 77 at the tip of the right arm 75 corresponds to the height of the left string 9 held by the left chuck 71. Next, as shown in Figure 44, the right arm 75 moves to the left with the clamp portion 77 at the tip of the right arm 75 released. As a result, the portion 9a of the left string 9 that is stretched between the left arm 76 and the left chuck 71 becomes caught in the clamp portion 77 at the tip of the right arm 75. After that, as shown in Figure 45, the right arm 75 returns from the tilted position to the horizontal position. As a result, the portion 9a of the left string 9 that is stretched between the left arm 76 and the left chuck 71 is inserted into the clamp portion 77 at the tip of the right arm 75.

[0114] <Clamping action of the right-side string 9 by the left-side arm 76> (First half) Next, as shown in Figure 45, the left arm 76 tilts so that the height of the clamp portion 77 at the tip of the left arm 76 corresponds to the height of the right string 9 held by the right chuck 70. Subsequently, as shown in Figure 46, the left arm 76 moves to the right with the clamp portion 77 at its tip released. As a result, the portion 9a of the right string 9 that is stretched between the right arm 75 and the right chuck 70 becomes caught in the clamp portion 77 at the tip of the left arm 76. After that, as shown in Figure 47, the left arm 76 moves to the left. As a result, the portion 9a of the right string 9 that is stretched between the right arm 75 and the right chuck 70 becomes inserted into the clamp portion 77 at the tip of the left arm 76. At the same time, the right arm 75 also moves to the right.

[0115] <Clamping action of the left string 9 by the right arm 75> (second half) <Clamping action of the right-side string 9 by the left-side arm 76> (second half) Subsequently, as shown in Figures 48 and 49, the clamp portion 77 at the tip of the right arm 75 closes and switches to a fully clamped state, and at the same time, the clamp portion 77 at the tip of the left arm 76 also closes and switches to a fully clamped state, and the clamp portions 77 at the tips of the right arm 75 and the left arm 76 grasp the left string 9 and the right string 9, respectively. After that, the left arm 76 returns from the tilted position to the horizontal position.

[0116] Next, the pulling motion of the right arm 75 from the right side of the string 9 and the pulling motion of the left arm 76 from the left side of the string 9 are performed simultaneously and in sync on both sides.

[0117] <Pulling action from the right-side string 9 of the right-side arm 75> As shown in Figures 49 and 50, while the clamp portion 77 at the tip of the right arm 75 is gripping the left string 9, the right arm 75 is moved to the right, and the right arm 75 is pulled out from the portion of the right string 9 that is wrapped around the outer circumference of the right arm 75. This pulling operation is performed while the clamp portion 77 at the tip of the right arm 75 is held in a fully clamped state.

[0118] <Pulling action from the right side of the left arm 76 to the string 9> As shown in Figures 49 and 50, while the left arm 76 is gripping the right string 9 with the clamp portion 77 at its tip, the left arm 76 is moved to the left, and the left arm 76 is pulled out from the portion of the left string 9 that is wrapped around the outer circumference of the left arm 76. This pulling operation is performed while the clamp portion 77 at the tip of the left arm 76 is held in a fully clamped state.

[0119] When the right arm 75 is pulled out from the right side of the string 9 and the left arm 76 is pulled out from the left side of the string 9 simultaneously, the left and right strings 9 are tied in a bow, as shown in Figure 50. At this time, the part of the string 9 held by the clamp part 77 at the tip of the right arm 75 becomes the right loop 102 of the bow, and the part of the string 9 held by the clamp part 77 at the tip of the left arm 76 becomes the left loop 102 of the bow.

[0120] During the secondary knotting process described above, the left and right side frames 11, located at the positions shown by the dashed lines in Figure 1, move away from each other in the left-right direction, then move backward (downward in the figure), and then move closer to each other in the left-right direction, performing a series of parallel movements until they return to the positions shown in Figure 1.

[0121] [Tightening the bow knot] Next, as shown in Figures 51 and 52, the left and right tightening pieces 96, in a width-reduced position with their distance from left to right narrowed, move from the rear side (back of the page in the diagram) to the front side (front of the page in the diagram) of the bag with string 1 and are inserted into the space below the bow knot 100.

[0122] Subsequently, as shown in Figure 53, the left and right tightening pieces 96 rise while their distance from each other in the left-right direction is narrowed, and come into contact with the lower surface of the bow knot 100. Then, as shown in Figure 54, the left and right tightening pieces 96 open to the left and right, forcibly spreading the portions of the left and right cords 9 closer to the base of the knot 100, thereby tightening the bow knot 100. At this time, the clamp portion 77 at the tip of the right arm 75 and the clamp portion 77 at the tip of the left arm 76 are both held in a fully clamped state.

[0123] Subsequently, as shown in Figure 55, the distance between the left and right tightening pieces 96 narrows and they move backward (towards the back of the paper in the figure), and they come out of the space below the bow knot 100. Then, the clamp portion 77 at the tip of the right arm 75 and the clamp portion 77 at the tip of the left arm 76 switch from a fully clamped state to a released state. Then, the right arm 75 and the left arm 76 tilt simultaneously so that the tips of the right arm 75 and the left arm 76 rise, and the clamp portions 77 at the tips of the right arm 75 and the left arm 76 come out of the left and right loop portions 102 of the bow knot. This completes the bow knot shown in Figures 56 and 57.

[0124] [Bag transfer process from secondary knotting section 6 to bag discharge section 7] Subsequently, the left and right side frames 11 shown in Figure 1 move forward (upward in the figure) as a single unit, pushing the bag with the string 1 against the back plate 21, and it is discharged from the secondary knot section 6 to the bag discharge section 7.

[0125] As shown in Figures 28 and 29, in the operation of wrapping the right string 9 on the right arm 45 in the primary knotting section 5 (see Figure 3), the right arm 45 is moved to the front (upper side in the figure) and the right chuck 40 is moved to the rear (lower side in the figure). This allows the right string 9 to be wrapped deeply around the outer circumference of the right arm 45 from the front (upper side in the figure), stabilizing the position of the right string 9. Similarly, in the operation of wrapping the left string 9 on the left arm 46, the left arm 46 is moved to the rear (lower side in the figure) and the left chuck 41 is moved to the front (upper side in the figure). This allows the left string 9 to be wrapped deeply around the outer circumference of the left arm 46 from the rear (lower side in the figure), stabilizing the position of the left string 9. Therefore, as shown in Figure 31, the operation of gripping the portion 9a of the left string 9 that is stretched between the left arm 46 and the left chuck 41 with the clamp portion 47 at the tip of the right arm 45, and the operation of gripping the portion 9a of the right string 9 that is stretched between the right arm 45 and the right chuck 40 with the clamp portion 47 at the tip of the left arm 46, are less likely to fail, making it possible to stably tie a single knot between the left and right strings 9.

[0126] Similarly, as shown in Figures 41 and 42, in the operation of wrapping the right string 9 on the right arm 75 in the secondary knotting section 6 (see Figure 3), the right arm 75 is moved to the rear (downward in the figure) and the right chuck 70 is moved to the front (upward in the figure). This allows the right string 9 to be wrapped deeply around the outer circumference of the right arm 75 from the rear (downward in the figure), stabilizing the position of the right string 9. Similarly, in the operation of wrapping the left string 9 on the left arm 76, the left arm 76 is moved to the front (upward in the figure) and the left chuck 71 is moved to the rear (downward in the figure). This allows the left string 9 to be wrapped deeply around the outer circumference of the left arm 76 from the front (upward in the figure), stabilizing the position of the left string 9. Therefore, as shown in Figure 48, the operation of gripping the portion 9a of the left string 9 that is stretched between the left arm 76 and the left chuck 71 with the clamp portion 77 at the tip of the right arm 75, and the operation of gripping the portion 9a of the right string 9 that is stretched between the right arm 75 and the right chuck 70 with the clamp portion 77 at the tip of the left arm 76, are less likely to fail, making it possible to stably tie the left and right strings 9 in a bow.

[0127] Furthermore, this string-tying device employs pivot actuators 42 and 43 that pivot around a right pivot axis 52 and a left pivot axis 54, which are arranged side by side, as a mechanism for moving the right chuck 40 and the left chuck 41 of the primary knotting section 5 (see Figure 3) in the front-back direction. As shown in Figure 29, when the right chuck 40 is moved during the winding operation of the right string 9 onto the right arm 45, the distance from the part of the right string 9 that is gripped by the right chuck 40 to the base of the right string 9 does not change easily, preventing the right string 9 from becoming loose or excessively pulled, and ensuring that the position of the right string 9 remains stable. Similarly, when winding the left string 9 onto the left arm 46, the distance from the part of the left string 9 that is gripped by the left chuck 41 to the base of the left string 9 does not change easily when the left chuck 41 is moved, preventing the left string 9 from becoming loose or excessively pulled, and ensuring that the position of the left string 9 remains stable.

[0128] Similarly, this string-tying device employs pivot actuators 72 and 73 that pivot around a right pivot axis 82 and a left pivot axis 84, which are arranged side by side, to move the right chuck 70 and the left chuck 71 of the secondary knotting section 6 (see Figure 3) in the front-back direction. As shown in Figure 42, when the right chuck 70 is moved during the winding operation of the right string 9 onto the right arm 75, the distance from the part of the right string 9 that is gripped by the right chuck 70 to the base of the right string 9 does not change easily, preventing the right string 9 from becoming loose or excessively pulled, and ensuring that the position of the right string 9 remains stable. Similarly, when winding the left string 9 onto the left arm 76, the distance from the part of the left string 9 that is gripped by the left chuck 71 to the base of the left string 9 does not change easily when the left chuck 71 is moved, preventing the left string 9 from becoming loose or excessively pulled, and ensuring that the position of the left string 9 remains stable.

[0129] Furthermore, as shown in Figure 24, the left and right first string transfer chucks 25 of this string-tying device are designed to transfer the middle portion of the left and right strings 9, closer to the root than the tip portion, to the right chuck 40 and the left chuck 41, rather than the tip portions of the left and right strings 9. Therefore, the right chuck 40 and the left chuck 41 of the primary knotting section 5 (see Figure 3) grip the middle portion of the left and right strings 9. Here, the tip portions of the right and left strings 9 are the parts that constitute the straight portion 101 of the string 9 extending from the knot 100 when the left and right strings 9 are tied together to form a knot 100, as shown in Figures 56 and 57. Therefore, when the left and right strings 9 are tied together to form a knot 100, it is possible to prevent the straight portion 101 of the string 9 extending from the knot 100 from being bent or damaged by the gripping of the right chuck 40 and the left chuck 41 of the primary knotting section 5 (see Figure 3).

[0130] Similarly, as shown in Figure 38, the second string-passing chucks 26 on the left and right sides of this string-tying device are designed to pass the middle portion of the strings 9, closer to the root than the tips, to the right chuck 70 and the left chuck 71, rather than the tips. As a result, the right chuck 70 and the left chuck 71 of the secondary knotting section 6 (see Figure 3) grip the middle portion of the strings 9. Therefore, as shown in Figures 56 and 57, when the left and right strings 9 are tied together to form a knot 100, it is possible to prevent the straight portion 101 of the string 9 extending from the knot 100 from being bent or damaged by the gripping of the right chuck 70 and the left chuck 71 of the secondary knotting section 6 (see Figure 3).

[0131] Furthermore, this knot-tying device is configured so that the clamp portions 47 at the tips of the left and right arms 45 and 46 shown in Figure 6 can be switched between a half-clamped state and a fully clamped state. As shown in Figure 35, by moving the left and right arms 45 and 46 with the clamp portions 47 at the tips of the left and right arms 45 and 46 in a half-clamped state that allows movement of the cord 9 in the longitudinal direction, the left and right cords 9 can be quickly tied in a single knot while preventing them from being pulled excessively. Then, as shown in Figure 36, by moving the left and right arms 45 and 46 with the clamp portions 47 at the tips of the left and right arms 45 and 46 in a fully clamped state that prevents movement of the cord 9 in the longitudinal direction, the tightness of the single knot can be increased.

[0132] Furthermore, as shown in Figure 36, this knot-tying device is designed so that when the clamp portions 47 at the tips of the left and right arms 45 and 46 are fully clamped and the left and right strings 9 are pulled, the electric motor of the left and right arm left and right movement mechanism 69 shown in Figure 6 is torque-controlled so that the pulling force on the left and right strings 9 is equal in magnitude. This prevents the single knot 99 shown in Figure 36 from being shifted to one side in the left-right direction from the exact midpoint between the roots of the left and right strings 9. In other words, when the right arm 45, which grasps the left string 9, and the left arm 46, which grasps the right string 9, are moved in the left-right direction to form the knot 99, the shape of the knot 99 portion of the left and right strings 9 may not be symmetrical, resulting in a relatively straight side and a side that wraps around the straight side. In this case, instead of torque-controlling the right-side electric motor for moving the right arm 45 and the left-side electric motor for moving the left arm 46, it is also possible to control the position so that the amount of movement of the left and right arms 45 and 46 is the same. However, if this is done, the winding side of the knot 99 of the left and right strings 9 will be pulled too much more than the straight side, and as a result, the position of the knot 99 may be shifted to one side in the left-right direction from the exact midpoint between the bases of the left and right strings 9. In contrast, by torque-controlling the right-side electric motor for moving the right arm 45 and the left-side electric motor for moving the left arm 46, the winding side and the straight side of the knot 99 of the left and right strings 9 will be pulled with the same force, so it is possible to prevent the winding side from being pulled too much more than the straight side, and as a result, it is possible to prevent the single knot 99 from being shifted to one side in the left-right direction from the exact midpoint between the bases of the left and right strings 9.

[0133] Furthermore, as shown in Figures 12 and 13, the clamp portions 77 at the tips of the left and right arms 75 and 76 of the secondary knotting section 6 (see Figure 3) grip the left and right strings 9 in a orientation where the thickness direction of the flat string is in the left-right direction. As a result, as shown in Figures 56 and 57, the loop portion 102 of the bowknot has a neat shape (the flat string makes a smooth U-turn at the tip of the loop), making it possible to form an aesthetically pleasing bowknot. In addition, the loop portion 102 of the bowknot is not bent or damaged.

[0134] Furthermore, as shown in Figures 53 and 54, this knot-tying device inserts the left and right tightening pieces 96 under the bow knot 100 and tightens the bow knot 100 by opening the tightening pieces 96 to the left and right. This allows the bow knot 100 to be tightened without shortening the straight portion 101 of the string 9 extending from the bow knot 100, resulting in the formation of a visually appealing bow knot. In other words, as a method to tighten the bow knot 100 as shown in Figure 57, a common method is to pull the loop portion 102 of the bow knot strongly to the left and right. However, in this case, the straight portion 101 of the string 9 extending from the bow knot 100 becomes shorter, resulting in a less visually appealing bow knot. In contrast, as shown in Figures 53 and 54, by inserting the left and right tightening pieces 96 under the bow knot 100 and opening the left and right tightening pieces 96 to the left and right, it becomes possible to tighten the bow knot 100 without shortening the straight portion 101 of the cord 9 extending from the bow knot 100, thereby forming a visually appealing bow knot.

[0135] Furthermore, as shown in Figures 53 and 54, when tightening a bow knot, this knot-tying device grips the left and right loops 102 of the bow knot with the clamp portions 77 at the tips of the left and right arms 75 and 76, and tightens the knot while gripping them. As a result, the size of the loops of the bow knot does not change easily when tightened, and the left and right loops of the bow knot tend to be the same size. Therefore, it is possible to form a visually appealing bow knot.

[0136] In the above embodiment, a stringed bag 1 for storing grains such as rice and wheat was used as an example of a stringed article having strings 9 on both sides. However, this invention can also be applied to string-tying devices for tying together strings 9 of stringed articles other than stringed bags 1. [Explanation of Symbols]

[0137] 1. Bag with drawstring 9 strings 9a The part that spans between the arm of the string and the zipper. 25. First cord transfer zipper 26. Second cord transfer zipper 40 Right-side zipper 41 Left side zipper 42 Right-side swivel actuator 43 Left-side swivel actuator 45 Right arm 46 Left arm 47 Clamp section 52 Right rotation axis 54 Left rotation axis 69 Arm left and right movement mechanism 70 Right-side zipper 71 Left side zipper 72 Right-side swivel actuator 73 Left-side swivel actuator 75 Right arm 76 Left arm 77 Clamp section 82 Right rotation axis 84 Left rotation axis 95 Arm left and right movement mechanism 96 Re-tightening piece 100 Bow knots

Claims

1. A string-tying device for tying together left and right strings (9) extending from a stringed article (1), The right zipper (40, 70) and the left zipper (41, 71) are positioned above the stringed article (1) at a distance from each other, The right arm (45, 75) and the left arm (46, 76) are provided below the right chuck (40, 70) and the left chuck (41, 71) so as to extend in the left-right direction, and each has a clamp portion (47, 77) at its tip for gripping the string (9), A right-side chuck forward / backward movement mechanism for moving the right-side chucks (40, 70) in the forward / backward direction, A left chuck forward and backward movement mechanism for moving the left chuck (41, 71) in the forward and backward direction, A right arm forward / backward movement mechanism for moving the right arm (45, 75) in the forward / backward direction, A left arm forward / backward movement mechanism for moving the left arm (46, 76) in the forward / backward direction, A right arm left-right movement mechanism (69, 95) moves the right arm (45, 75) in the left-right direction, The left arm (46, 76) is further moved by a left arm left-right movement mechanism (69, 95) in the left-right direction. With the right string (9) gripped by the right chuck (40, 70), the right arm forward / backward movement mechanism moves the right arm (45, 75) to one side in the forward / backward direction, and the right chuck movement mechanism moves the right chuck (40, 70) to the other side in the forward / backward direction, thereby winding the right string (9) around the outer circumference of the right arm (45, 75) from one side in the forward / backward direction, and the left With the left string (9) gripped by the side chucks (41, 71), the left arm forward / backward movement mechanism moves the left arm (46, 76) to the other side in the forward / backward direction, and the left chuck forward / backward movement mechanism moves the left chuck (41, 71) to one side in the forward / backward direction, thereby performing the winding operation of the left string (9) onto the left arm (46, 76) so that the left string (9) is wrapped around the outer circumference of the left arm (46, 76) from the other side in the forward / backward direction. After the winding operation of the right string (9) onto the right arm (45, 75) and the winding operation of the left string (9) onto the left arm (46, 76), the right arm left-right movement mechanism (69, 95) moves the right arm (45, 75) to the left, and the clamp portion (47, 77) at the tip of the right arm (45, 75) grasps the portion (9a) of the left string (9) that is stretched between the left arm (46, 76) and the left chuck (41, 71). The left arm (45, 75) performs a clamping operation on the left string (9), and the left arm left-right movement mechanism (69, 95) moves the left arm (46, 76) to the right, and the clamping portion (47, 77) at the tip of the left arm (46, 76) grasps the portion (9a) of the right string (9) that is stretched between the right arm (45, 75) and the right chuck (40, 70), thereby performing a clamping operation on the right string (9) by the left arm (46, 76). After the clamping operation of the left string (9) by the right arm (45, 75) and the clamping operation of the right string (9) by the left arm (46, 76), the right arm (45, 75) is moved to the right by the right arm left / right movement mechanism (69, 95) while the left string (9) is still being grasped by the clamp portion (47, 77) at the tip of the right arm (45, 75), and the right arm (45, 75) is then pulled out from the portion of the right string (9) that is wrapped around the outer circumference of the right arm (45, 75). A string-tying device that ties the left and right strings (9) together by simultaneously performing a pulling operation from the right string (9) and a pulling operation of the left arm (46, 76) from the left string (9) by moving the left arm (46, 76) to the left using the left arm left-right movement mechanism (69, 95) while the right string (9) is grasped by the clamp portion (47, 77) at the tip of the left arm (46, 76), and then pulling the left arm (46, 76) from the portion of the left string (9) that is wrapped around the outer circumference of the left arm (46, 76).

2. The aforementioned right-side chuck forward and backward movement mechanism is a right-side pivot actuator (42, 72) that pivots the right-side chuck (40, 70) from a position aligned to the right of the right pivot axis (52, 82) to one side in the forward and backward direction around the right pivot axis (52, 82). The knot-tying device according to claim 1, wherein the left-side chuck forward and backward movement mechanism is a left-side pivot actuator (43, 73) that pivots the left-side chuck (41, 71) from a position aligned to the left of the left pivot axis (54, 84), which is positioned to the left of the right pivot axis (52, 82), to the other side in the forward and backward direction, around the left pivot axis (54, 84).

3. It has a right-side string transfer zipper (25, 26) that transfers the right-side string (9) to the right-side zipper (40, 70), and a left-side string transfer zipper (25, 26) that transfers the left-side string (9) to the left-side zipper (41, 71), The right-side cord transfer zippers (25, 26) are provided to transfer the middle portion of the right-side cord (9) to the right-side zippers (40, 70). The string-tying device according to claim 1 or 2, wherein the string-passing chucks (25, 26) on the left side are provided to pass the middle portion of the string (9) on the left side to the left-side chucks (41, 71).

4. The clamp portion (47) at the tip of the right arm (45) is configured to be switchable between an open state in which it does not grip the string (9), a semi-clamped state in which it grips the string (9) in a direction that intersects the longitudinal direction of the string (9) relative to the clamp portion (47) while allowing movement of the string (9) in the longitudinal direction relative to the clamp portion (47), and a fully clamped state in which it grips the string (9) in a direction that restricts both movement of the string (9) in the longitudinal direction relative to the clamp portion (47) and movement in a direction that intersects the longitudinal direction. The clamp portion (47) at the tip of the left arm (46) is also configured to be switchable between an open state in which it does not grip the string (9), a semi-clamped state in which it grips the string (9) in a direction that intersects the longitudinal direction of the string (9) relative to the clamp portion (47) while allowing movement of the string (9) in the longitudinal direction relative to the clamp portion (47), and a fully clamped state in which it grips the string (9) in a direction that restricts both movement of the string (9) in the longitudinal direction relative to the clamp portion (47) and movement in a direction that intersects the longitudinal direction. In the operation of pulling the right arm (45) out of the right string (9), before the left end of the string (9), which is grasped by the clamp portion (47) at the tip of the right arm (45), comes out to the right from the portion of the right string (9) that is wrapped around the outer circumference of the right arm (45), the clamp portion (47) is kept in the half-clamped state and the right arm (45) is moved to the right. After the left end of the string (9), which is grasped by the clamp portion (47) at the tip of the right arm (45), comes out to the right from the portion of the right string (9) that is wrapped around the outer circumference of the right arm (45), the clamp portion (47) is switched to the fully clamped state and the right arm (45) is moved further to the right. In the pulling operation of the left arm (46) from the left string (9), the clamp portion (47) is kept in the half-clamped state and the left arm (46) is moved to the left until the tip of the right string (9), which is grasped by the clamp portion (47) at the tip of the left arm (46), comes out to the left from the portion of the left string (9) that is wrapped around the outer circumference of the left arm (46), and after the tip of the right string (9), which is grasped by the clamp portion (47) at the tip of the left arm (46), comes out to the left from the portion of the left string (9) that is wrapped around the outer circumference of the left arm (46), the clamp portion (47) is switched to the fully clamped state and the left arm (46) is moved further to the left, thereby tying a single knot between the left and right strings (9), as described in claim 1 or 2.

5. The right arm left-right movement mechanism (69) comprises a right-side electric motor and a right-side motion conversion mechanism that converts the rotation of the electric motor into left-right movement of the right arm (45). The left arm left-right movement mechanism (69) comprises a left-side electric motor and a left-side motion conversion mechanism that converts the rotation of the electric motor into left-right movement of the left arm (46). The string-tying device according to claim 4, wherein, in the pulling operation of the right arm (45) from the right string (9) and the pulling operation of the left arm (46) from the left string (9), when the right arm (45) moves to the right and pulls the left string (9) to the right, and at the same time when the left arm (46) moves to the left and pulls the right string (9) to the left, the torque of the right electric motor and the left electric motor are controlled so that the force with which the right arm (45) pulls the left string (9) and the force with which the left arm (46) pulls the right string (9) are equal in magnitude.

6. The clamp portion (77) at the tip of the right arm (75) is configured to be switchable between an open state in which it does not grip the string (9) and a fully clamped state in which it grips the string (9) in such a way that it restricts both the longitudinal movement of the string (9) relative to the clamp portion (77) and the movement of the string (9) in a direction intersecting the longitudinal direction. The clamp portion (77) at the tip of the left arm (76) is also configured to be switchable between an open state in which it does not grip the string (9) and a fully clamped state in which it grips the string (9) in such a way that it restricts both the longitudinal movement of the string (9) relative to the clamp portion (77) and the movement of the string (9) in a direction intersecting the longitudinal direction. The string-tying device according to claim 1 or 2, wherein in the operation of pulling out the right string (9) of the right arm (75), the clamp portion (77) at the tip of the right arm (75) is fully clamped and the right string (9) is pulled out to the right from the portion wrapped around the outer circumference of the right arm (75), and in the operation of pulling out the left string (9) of the left arm (76), the clamp portion (77) at the tip of the left arm (76) is fully clamped and the left string (9) is pulled out to the left from the portion wrapped around the outer circumference of the left arm (76), thereby tying a bow knot between the left and right strings (9).

7. The left and right strings (9) are flat, flat strings. The clamp portion (77) at the tip of the right arm (75) is configured to grasp the right side of the flat cord (9) in a direction where the thickness direction of the cord is in the left-right direction. The string tying device according to claim 6, wherein the clamp portion (77) at the tip of the left arm (76) is configured to grasp the left string (9) in a direction in which the thickness direction of the flat string is in the left-right direction.

8. Left and right tightening pieces (96) extending in the front-to-back direction, A tightening piece forward / backward movement device for moving the left and right tightening pieces (96) together in the forward / backward direction, The device further includes a tightening piece left-right moving device that moves the left and right tightening pieces (96) in opposite directions in the left-right direction, The string-tying device according to claim 6, wherein after tying the left and right strings (9) in a bow, the left and right tightening pieces (96) are moved in the front-rear direction by the tightening piece front-rear moving device to insert the left and right tightening pieces (96) under the bow knot (100), and then the left and right tightening pieces (96) are opened to the left and right by the tightening piece left-right moving device to tighten the bow knot (100).

9. The knot-tying device according to claim 8, wherein when tightening the bow knot (100) by opening the left and right tightening pieces (96) to the left and right, the tightening is performed while holding both the clamp portion (77) at the tip of the right arm (75) and the clamp portion (77) at the tip of the left arm (76) in the fully clamped state.

10. A method of tying knots for connecting the left and right strings (9) extending from an item (1) with a string attached, The right zipper (40, 70) and the left zipper (41, 71) are positioned above the stringed article (1) at a distance from each other, The right arm (45, 75) and the left arm (46, 76) are provided below the right chuck (40, 70) and the left chuck (41, 71) so as to extend in the left-right direction, and each has a clamp portion (47, 77) at its tip for gripping the string (9), A right-side chuck forward / backward movement mechanism for moving the right-side chucks (40, 70) in the forward / backward direction, A left chuck forward and backward movement mechanism for moving the left chuck (41, 71) in the forward and backward direction, A right arm forward / backward movement mechanism for moving the right arm (45, 75) in the forward / backward direction, A left arm forward / backward movement mechanism for moving the left arm (46, 76) in the forward / backward direction, A right arm left-right movement mechanism (69, 95) moves the right arm (45, 75) in the left-right direction, Using the left arm left-right movement mechanism (69, 95) which moves the left arm (46, 76) in the left-right direction, With the right string (9) gripped by the right chuck (40, 70), the right arm forward / backward movement mechanism moves the right arm (45, 75) to one side in the forward / backward direction, and the right chuck movement mechanism moves the right chuck (40, 70) to the other side in the forward / backward direction, thereby winding the right string (9) around the outer circumference of the right arm (45, 75) from one side in the forward / backward direction, and the left With the left string (9) gripped by the side chucks (41, 71), the left arm forward / backward movement mechanism moves the left arm (46, 76) to the other side in the forward / backward direction, and the left chuck forward / backward movement mechanism moves the left chuck (41, 71) to one side in the forward / backward direction, thereby performing the winding operation of the left string (9) onto the left arm (46, 76) so that the left string (9) is wrapped around the outer circumference of the left arm (46, 76) from the other side in the forward / backward direction. After the winding operation of the right string (9) onto the right arm (45, 75) and the winding operation of the left string (9) onto the left arm (46, 76), the right arm left-right movement mechanism (69, 95) moves the right arm (45, 75) to the left, and the clamp portion (47, 77) at the tip of the right arm (45, 75) grasps the portion (9a) of the left string (9) that is stretched between the left arm (46, 76) and the left chuck (41, 71). The left arm (45, 75) performs a clamping operation on the left string (9), and the left arm left-right movement mechanism (69, 95) moves the left arm (46, 76) to the right, and the clamping portion (47, 77) at the tip of the left arm (46, 76) grasps the portion (9a) of the right string (9) that is stretched between the right arm (45, 75) and the right chuck (40, 70), thereby performing a clamping operation on the right string (9) by the left arm (46, 76). After the clamping operation of the left string (9) by the right arm (45, 75) and the clamping operation of the right string (9) by the left arm (46, 76), the right arm (45, 75) is moved to the right by the right arm left / right movement mechanism (69, 95) while the left string (9) is still being grasped by the clamp portion (47, 77) at the tip of the right arm (45, 75), and the right arm (45, 75) is then pulled out from the portion of the right string (9) that is wrapped around the outer circumference of the right arm (45, 75). A method of tying knots by simultaneously performing the pulling motion from the right string (9) and the pulling motion of the left arm (46, 76) from the left string (9) by moving the left arm (46, 76) to the left using the left arm left-right movement mechanism (69, 95) while the right string (9) is grasped by the clamp portion (47, 77) at the tip of the left arm (46, 76), and pulling the left arm (46, 76) from the portion of the left string (9) that is wrapped around the outer circumference of the left arm (46, 76).

Images