Doffing device for an automatic winder

Abstract

 The present invention provides a doffing device (1) for an automatic winder which has the ability to carry out bunch winding for winding packages requiring bunch winding, while reliably winding a yarn end around an intermediate portion of an empty tube for winding packages not requiring bunch winding. The doffing device (1) has bunch winding forming means (BBA) for forming a bunch winding portion around one end of an empty tube (T), straight winding forming means (BAA) for winding a yarn around an intermediate portion of the empty tube (T), and switching means for selecting either the bunch winding forming means or the straight winding forming means to form a desired wound yarn.

Description

[0001] The present invention relates to an automatic winder that winds a yarn wound around supplying packages such as spinning packages produced by a spinning machine, into a winding package of a larger diameter, and in particular, to a doffing device for an automatic winder which unloads a full winding package while supplying a new empty tube.

[0002] Automatic winders conventionally wind a given length of yarn from spinning packages produced by a ring spinning machine, into a winding package of a larger diameter.

[0003] Such an automatic winder comprises a plurality of winding units arranged in a line, and a doffing device that unloads full winding packages into which yarns have been wound by the plurality of winding units, the doffing device further installing new empty tubes.

[0004] To unload a full winding package with a given length of yarn, the doffing device cuts the yarn and grips a yarn end for the next winding start, and the doffing device then winds the yarn a number of times around one end of a new empty tube to be supplied, to form a bunch winding portion, and the doffing device the n resumes winding at a position away from the bunch winding portion.

[0005] During a postprocess of unwinding yarns from packages, the bunch winding is utilized to continuously unwind yarns from a plurality of winding packages. A plurality of packages can be continuously used by splicing a yarn end of the bunch winding of the first winding package and a yarn end of an outermost layer of the next winding package. Thus, a normal procedure of winding in the automatic winder involves winding the winding start yarn end around one end of an empty tube to form a bunch winding portion, and then carrying out regular winding in a traverse area away from the bunching winding portion to form a winding package.
The present applicant has already applied a doffing device for an automatic winder which comprises a pair of bunch forming devices so that a bunch winding portion can be generated on either the left or right side of an empty tube (see, for example, the Unexamined Japanese Patent Application Publication (Tokkai) No. 2000-255901 (p.1 to 8, Figure 1).

[0006] Bunch winding may be unnecessary depending on use conditions, for example, where each winding package can be used only once during the postprocess. Various problems may occur while a yarn is being drawn out from a package with a bunch winding portion, and the yarn in the bunch winding portion is unwound and entangled with another yarn. The present applicant has thus already applied a method of winding a yarn in which, to produce a winding package without a bunch winding portion, winding is started by winding a yarn end once around a substantially intermediate portion of an empty bobbin (empty tube) (see, for example, the Examined Japanese Patent Application Publication (Tokko-Hei) No.7-17312 (p.1 to 3, Figure 1).

[0007] In an automatic winder comprising a large number of winding units, all winding units may wind the same yarn type under the same winding conditions or the winding units may wind a plurality of yarn types under different winding conditions.

[0008] Some winding conditions require bunch winding, while others do not require bunch winding but only winding of a yarn end around the intermediate portion of an empty tube.

[0009] However, the prior art requires the selection of either a doffing device that carries out bunch winding or a doffing device that does not carry out bunch winding but start winding by once winding a yarn around the intermediate portion of an empty tube.

[0010] Thus, both winding packages with bunch winding portions and without any bunch winding portions are simultaneously produced as follows. A doffing device designed for bunch winding is first used to all winding packages and the operator then removes bunch winding portions from packages not requiring bunch winding.

[0011] When winding packages are individually used without removing bunch winding portions and connecting the yarn ends of winding packages together, the yarn end wound a number of times into a bunch winding portion is unwound and entangled with another yarn. By this cause, yarn breakage, a variation in tension, or the like may disadvantageously occur.

[0012] With a method of resuming winding simply by winding a yarn end around the intermediate portion of an empty tube, winding may disadvantageously become unstable to deform a winding package where the yarn type has a small coefficient of friction or where the yarn end is wound around a slippery empty tube surface.

[0013] An object of the present invention to solve these problems by providing a doffing device for an automatic winder which has the ability to execute winding by carrying out bunch winding for winding packages requiring bunch winding, while reliably winding a yarn end around an intermediate portion of an empty tube for winding packages not requiring bunch winding.

[0014] To accomplish the above object, an invention in accordance with Claim 1 pro vides a doffing device for an automatic winder which unloads a full winding package while supplying an empty tube and which winds a supplying package-side yarn end around the empty tube to resume winding, the doffing device being characterized by comprising bunch winding forming means for forming a bunch winding portion around one end of the empty tube, straight winding forming means for winding a yarn around an intermediate portion of the empty tube, and switching means for selecting either the bunch winding forming means or the straight winding forming means.

[0015] The invention in accordance with Claim 1 configured as described above allows the single doffing device to carry out bunch winding for winding packages requiring bunch winding, while carrying out straight winding on the intermediate portion of the empty tube for winding packages not requiring bunch winding.

[0016] An invention in accordance with Claim 2 is characterized in that the straight winding forming means comprises a first yarn gripping device which cuts the yarn and which grips a yarn end, a first yarn transferring device, a winding rotor including a yarn receiving member that receives a yarn end gripped by the yarn gripping device and a tube holding member, and a rotor swing arm that swings the winding rotor.

[0017] The invention in accordance with Claim 2 configured as described above enables the yarn end to be subjected to straight winding, to be reliably gripped and wound around the empty tube with a predetermined number of times.

[0018] An invention in accordance with Claim 3 is characterized in that the tube holding member of the winding rotor receives and holds a new empty tube from a chucker arm that grips and transfers the empty tube, and the yarn receiving member rotates a number of times around the tube holding member holding the empty tube, to form a straight winding portion in which the yarn is wound a given number of times.

[0019] The invention in accordance with Claim 3 configured as described above enables the yarn to be wound a required number of times depending on the yarn type or the type of the empty tube. The yarn end can be reliably wound so as not to get loose.

[0020] An invention in accordance with Claim 4 is characterized in that the chucke r arm grips one empty tube housed in tube stocker that houses a plurality of empty tubes and delivers the empty tube to the tube holding member and which holds again the empty tube around which a straight portion has been formed and transfers the empty tube to a cradle position in a winding portion.

[0021] The invention in accordance with Claim 4 configured as described above allows a plurality of empty tubes to be housed in the tube stocker. This enables a winding operation to be automatically performed for a long time so that winding packages are produced while carrying out straight winding on the intermediate portion of each empty tube.

[0022] An invention in accordance with Claim 5 is characterized in that the bunch winding forming means comprises second yarn gripping device that cuts a yarn and grips a yarn end and a second yarn transferring device that guides the yarn end gripped by the second yarn gripping device, to a yarn bunch winding position.

[0023] With the invention in accordance with Claim 5 configured as described above, the selection of bunch winding ensures that the yarn end is guided to the predetermined position on the empty tube to form a bunch winding portion.

[0024] An invention in accordance with Claim 6 is characterized in that the switching means comprises one change-over valve that simultaneously controllably drives a first driving cylinder and a second driving cylinder in opposite directions, the first driving cylinder driving the first yarn gripping device and the yarn transferring device provided in the straight winding forming means, the second driving cylinder driving the second yarn gripping device and the second yarn transferring device provided in the bunch winding forming means.

[0025] With the invention in accordance with Claim 6 configured as described above, the simple control of one change-over valve enables the selection of only either the bunch winding forming means or the straight winding forming means for reliable driving.

[0026] According to the present invention, the doffing device comprises the bunch forming means for forming a bunch winding portion at one end of an empty tube, the straight winding forming means for winding the yarn around the intermediate portion of the empty tube, and the switching means for selecting either the bunch winding forming means or the straight winding forming means to form a desired winding yarn. Consequently, the provision of a single doffing device enables bunch winding to be carried out for winding packages requiring bunch winding, while enabling the yarn end to be wound around the intermediate portion of the empty tube for winding packages not requiring bunch winding.

[0027] With reference to the enclosed Figures, a description will be given of an embodiment of a doffing device for an automatic winder in accordance with the present invention.

Figure 1 is a schematic side view of an automatic winder comprising a doffing device in accordance with the present invention.

Figure 2 is a front view of the doffing device.

Figure 3 is a sectional view of an essential part of the doffing device.

Figure 4 is a schematic diagram showing how to form a straight winding port;

Figure 4A shows that a yarn receiving member is gripping a yarn, and Figure 4B shows that a yarn is being wound to form a straight winding portion.

Figure 5 is a side view showing a driving portion for a yarn gripping device.

Figure 6 is a schematic plan view of a driving mechanism for the yarn gripping device and a yarn transferring device for the doffing device.

Figure 7 is a partly enlarged side view of a driving mechanism for the yarn transferring device for the doffing device.

Figure 8 is a perspective view of the yarn transferring device for the doffing device.

Figure 9 is a front view showing an example of an empty tube around which a straight winding portion has been formed and an empty tube around which a bunch winding portion has been formed; Figure 9A shows the empty tube around which the straight winding portion has been formed, and Figure 9B shows the empty tube around which the bunch winding portion has been formed.

Figure 10 is a schematic diagram showing the relationship between a bunch winding position and a yarn transferring position.

[0028] Figure 1 is a schematic side view of an automatic winder comprising the doffing device in accordance with the present invention. Figures 2 to 8 show the configurations of the entire doffing device and its essential parts.

[0029] The configuration of an entire automatic winder W will be described with reference to Figure 1. The automatic winder W is composed of a large number of winding units 10 arranged in a line in a direction perpendicular to the sheet of the drawing. Each of the winding units 10 unwinds and draws out a yarn Y from a supplying package B supplied to the bottom of the main body. The winding unit 10 winds the yarn Y around an empty tube T rotatably held by a cradle 11D arranged at an upstream side to form a winding package P of a larger diameter.

[0030] Each winding unit 10 comprises a yarn clearer 11A which detects a yarn defect and which has a yarn cutting function, a yarn splicing device 11 B, a traversing drum 11C that rotates while traversing the yarn Y, the cradle 11 D that rotatably supports the tube T, a lower-yarn sucking and holding member 12A which sucks the yarn end of the yarn Y drawn out from the supplying package B and which introduces the yarn end into the yarn splicing device 11B, and a suction arm 12B serving as an upper-yarn sucking and holding member which sucks and catches the yarn end of a winding package P and which introduces the yarn end into the yarn splicing device 11B.
With the above configuration, each winding unit 10 winds the yarns Y drawn out from a plurality of supplying packages B, while splicing them together, to form a winding package P of a large diameter. When a defect in the yarn Y being wound is detected, the defective portion is cut and removed. The winding package-side yarn end can then be spliced to the supplying package-side yarn end again to form a winding package P having no yarn defects.

[0031] The doffing device 1 is disposed as an automatic machine that performs a doffing operation of presetting the length of the yarn Y wound around the winding package P, unloading a full winding package P reached at a predetermined yarn length, and replacing the full winding package P with a new empty tube T.

[0032] The doffing device 1 is movable along a longitudinal direction of the machine body so as to perform a doffing operation on each winding unit in the automatic winder W having a large number of winding units 10 arranged in the longitudinal direction. The doffing device 1 moves along a rail 22B in a frame 22A located at the top of the winder main body 20. The doffing device 1 unloads the winding package P from a winding unit on which doffing has been requested to be carried out, and the doffing device 1 then installs the new empty tube T in the cradle 11 D to allow winding to be automatically resumed.

[0033] The full winding package P is unloaded from the cradle 11D by the doffing device 1, and the winding package P is then conveyed to a predetermined position by a conveyor 21 A installed in the rear of the machine body for discharge. The doffing device 1 further takes one empty tube T out of a tube stocker 21 B disposed in each winding unit to store a plurality of empty tubes. The doffing device 1 then installs the empty tube T in the cradle 11 D to resume a new winding operation.

[0034] Before resumption of a new winding operation, what is called a bunch winding portion is formed by winding the winding start yarn end around one end of the empty tube T with a number of times.

[0035] The doffing device 1 also has this function of forming a bunch winding portion. When doffing the full winding package P, the doffing device 1 catches and cuts a part of the yarn located at the tip of the lower-yarn sucking and holding member 12A gripping the next yarn end from the supplying package B. The doffing device 1 unloads the winding package P and then installs the empty tube T in the cradle 11 D. The doffing device 1 then winds the supplying package-side yarn end around one end of the empty tube T to form a bunch winding portion, thus resuming a new winding operation.

[0036] However, packages having no bunch winding portions may be desired as previously described. The doffing device 1 in accordance with the present invention has bunch winding forming means for forming a bunch winding portion around one end of the empty tube, a straight winding forming means for winding the yarn around the intermediate portion of the empty tube, and switching means for selecting either the bunch winding forming means or the straight winding forming means to form a desired wound yarn.

[0037] The doffing device 1 in accordance with the present invention will be described below in detail with reference to Figures 2 to 8.

[0038] As shown in Figure 2, the doffing device 1 comprises a housing 1A, and a right and left vertical frames 1B, 1C hung from the opposite sides of the housing 1A. A lateral pair of yarn gripping devices 3, 4 is disposed in the housing 1A, and the yarn gripping devices 3, 4 have yarn cutting and gripping members 3D, 4 D, respectively, installed at their tips.

[0039] The doffing device 1 also comprises a chucker arm 5 that takes one empty tube T out of the tube stocker 21 B to transfer it to the cradle 11D. The doffing device 1 further comprises a rotor swing arm 2 located in the left of the figure.

[0040] The rotor swing arm 2 is an essential part constituting the straight winding forming means for winding the yarn around the intermediate portion of the empty tube T. The rotor swing arm 2 is installed on a supporting shaft 1 E extended between the right vertical frame 1 B and the left vertical frame 1C so as be able to swing freely.

[0041] A winding rotor 2C is installed at the tip of an arm main body portion 2A of the rotor swing arm 2 so as to swing around a yarn receiving member 2D disposed on the winding rotor 2C. Rotative-driving transmitting means 2E is built into the arm main body portion 2A to swing the yarn receiving member 2D. The rotative-driving transmitting means 2E is composed of a belt and a pulley which transmit rotation of a separately provided driving motor 2B, and the rotative-driving transmitting means 2E swings the yarn receiving member 2D via the transmitting means 2E.

[0042] A fan-shaped guide plate 2F is installed at the upper end of the arm main body portion 2A of the rotor swing arm 2. A circular channel (see Figure 3) is formed in the guide plate 2F, and the guide plate 2F can be arbitrarily slid along the supporting shaft 1 E in the direction of arrow 2b in the figure by a cylinder 1 F having a rod fitted into the circular channel.
6 is a yarn transferring device having a first yarn transferring device 6A and a second yarn transferring device 6B disposed on the left vertical frame 1 B and the right vertical frame 1C, respectively. The yarn transferring device 6 can arbitrarily swing a yarn transferring lever 32 and a bunch lever 33 described later (see Figure 7), in the direction shown by arrow 6a in the figure. To actuate the first yarn gripping device 3, located on the left side, the first yarn transferring device 6A, also located on the left side, is also operated. To actuate the second yarn gripping device 4, located on the right side, the second yarn transferring device 6B, also located on the right side, is also operated.

[0043] In the present embodiment, the second yarn gripping device 4, located on the right side, and the second yarn transferring device 6B, also located on the right side, constitute bunch forming means BBA, and the first yarn gripping device 3, located on the left side, and the first yarn transferring device 6A, also located on the left side, constitute straight forming means BAA. That is, the doffing device 1 in accordance with the present invention comprises the bunch forming means BBA for forming a bunch winding portion around one end of the empty tube T and the straight winding forming means BAA for winding the yarn around the intermediate portion of the empty tube T. The doffing device 1 also has switching means (described later) for selecting either the bunch winding forming means or the straight winding forming means.

[0044] Now, the straight winding forming means will be described with reference to Figures 3 and 4.

[0045] To carry out straight winding, a selective driving device ST described later (see Figure 5) is switched in accordance with a preset program to actuate one of two groups constituting the straight winding forming means, for example, the first yarn gripping device 3 and first yarn transferring device 6A, both located on the left side, and the rotor swing arm 2.

[0046] The first yarn gripping device 3 comprises the cylinder portion 3A, a supporting portion 3B that supports the cylinder portion 3A, and the yarn gripping device 3D installed on the cylinder rod 3C. The yarn gripping device 3D is installed on the first yarn gripping device 3 via a driving cylinder 3E, and the yarn gripping device 3D has a function of cutting the yarn and gripping the yarn end, and the yarn gripping device 3D can be arbitrarily moved by the driving cylinder 3E.

[0047] The supporting portion 3B is supported on the vertical frame 1 B via a bearing 3F and is pivotable in the direction of arrow 3a. The supporting means 3B can move the gripping device 3D to a predetermined position via driving means (not shown in the drawings).

[0048] The rotor swing arm 2 rotatively drives the winding rotor 2C in the direction of arrow 2a in the figure by the driving motor 2B via the rotative-driving transmitting means 2E. The winding rotor 2C comprises the yarn receiving member 2D located at its outer periphery, and the tube holding member 2G located in its center and which can hold the empty tube T. Thus, when the yarn receiving member 2D rotates while gripping the yarn Y, the yarn receiving member 2D and the tube holding member 2G simultaneously rotate in the direction of arrow 2a.

[0049] Thus, after the chucker arm 5 gripping the empty tube T is located at a delivery position, the rotor swing arm 2 moves in the direction of arrow 2b, and the winding tube holding member 2G then once receives the empty tube T. At this state, the yarn receiving member 2D, which keep gripping the yarn Y drawn from the supplying package B, and the empty tube T then simultaneously rotate in the direction of arrow 2a. The rotation in the direction of arrow 2a draws the yarn Y out of the supplying package B and winds the yarn Y while applying a predetermined winding tension to the yarn Y. The yarn Y is thus wound around the empty tube T at a predetermined position with a predetermined number of rotations.

[0050] With reference to Figure 4, a description will be given of how to form a straight winding portion with the empty tube T received by the tube holding member 2G.

[0051] The tube holding member 2G, disposed in the winding rotor 2C of the rotor swing arm 2, is, for example, a cylinder member with three pawls which moves in a radial direction to increase or reduce its diameter. The diameter of the tube holding member 2G decreases to hold an outer peripheral portion of the empty tub e T or increases to hold an inner-diameter portion of the empty tube T. As shown in Figure 4A, the yarn T gripped by the yarn gripping device 3D of the yarn gripping device 3 is guided to a position where it engages with the yarn receiving member 2D, by the first yarn transferring device 6A, which can swing in the direction of arrow 6a in the figure. The yarn receiving member 2D is then driven to cut and grip the yarn Y.

[0052] After the yarn Y is cut and gripped, when the yarn transferring device 6A is swung to a position shown in Figure 4B, the yarn Y is guided to a position where a straight winding portion is formed. The winding rotor 2C and the empty tube T are then rotated in the direction of arrow 2a in the figure to wind the yarn Y a predetermined number of times to form a bunch winding portion BA.

[0053] That is, changing the standby positions of the first yarn transferring device 6A and the yarn receiving member 2D enables the position where the yarn is wound to be regulated to form a straight winding portion around the empty tube T at the predetermined position. Presetting the number of rotations of the winding rotor 2C enables a bunch winding portion with a predetermined number of windings to be formed around the empty tube T at the predetermined position.

[0054] The chucker arm 5 takes the empty tube T out of the tube stocker 21 B and transfers it to the cradle 11D. The chucker arm 5 thus comprises a supporting member 5A, a cylinder member 5B, and a chuck portion 5D supported at the tip of the cylinder member 5B via a connection member 5C as shown in Figure 3.

[0055] The supporting member 5A is rotatably installed on a supporting shaft 1 D extended between the right vertical frame 1 B and the left vertical frame 1C, and the supporting member 5A can be rotated in the direction of arrow 5a by driving means (not shown in the drawings). The supporting means 5A is expanded and contracted in the direction of arrow 5b in the figure by the cylinder member 5B, and this enables the chuck member 5D to be opened and closed.

[0056] Thus, the following operations can be arbitrarily performed in accordance with settings: the chuck portion 5D is moved to a position where it grips the empty tube T housed in the tube stocker 21 B, provided in each winding unit, the empty tube T gripped by the chuck portion 5D is transferred to the winding rotor 2C of the rotor swing arm 2, or the empty tube T is transferred to the cradle 11 D.

[0057] Figure 3 shows that the gripped empty tube T has been transferred to the winding rotor 2C. As shown in Figure 4, the tube holding member 2G then holds the empty tube T, and the yarn Y being gripped by the yarn gripping device 3D is re-gripped by the yarn receiving member 2D. The winding rotor 2C, integrally comprising the tube holding member 2G and the yarn receiving member 2D, is rotated a predetermined number of times.

[0058] In the present embodiment, with the outer periphery of one end of the empty tube T gripped by a plurality of gripping pieces located at respective positions and with the chuck portion 5D opening the chuck for the empty tube T, the rotor portion 2C is rotatively driven a predetermined number of times. A straight winding portion BA is formed at a particular position in a traverse area as shown in Figure 9A.

[0059] After a predetermined winding operation is performed, the chuck portion 5D holds again the empty tube T around which the straight winding portion BA has been formed and transfers it to the cradle position in the winding portion.

[0060] Now, the yarn gripping device will be described in brief with reference to Figures 5 to 8. The yarn gripping devices 3, 4 are the same components constituting a lateral pair and will thus be described using a common reference numeral.

[0061] As shown in Figure 5, the yarn gripping device 3, which is pivotable in the direction of arrow 3a via the bearing 3F, is driven via an operation lever 7B, a coil spring 7D, and a link rod 7E in synchronism with the rotation of a yarn gripping device driving cam 8B; the operation lever 7B is rotatably installed around an arm supporting shaft 7A, the coil spring 7D and link rod 7E are attached to the operation lever 7B, and the yarn gripping device driving cam 8B is installed around a cam shaft 8A. 7C is a cam follower that is a roller guide member urged by the coil spring 7D to always abut against a peripheral surface of the yarn gripping device driving cam 8B. Thus, when the cam shaft 8A is driven to rotate the yarn gripping device driving cam 8B, the operation lever 7B pivotally moves in conformity with the external shape of the cam to pivot the yarn gripping device 3.

[0062] The selective driving device ST, comprising a shaft 9A, a stop lever 9B, and a driving cylinder 9C, is disposed in each of the yarn gripping devices 3, 4, and the selective driving device ST drives the driving cylinder 9C in accordance with a preset program to arbitrarily displace the stop lever 9B between a posit ion where it inhibits the rotation of the operation lever 7B as shown by a solid line in the figure and a position where it does not inhibit the rotation of the operation lever 7B (as shown by a one long and two short alternate line in the figure). Thus, the stop lever 9B located as shown by the solid line in the figu re inhibits the rotation of the operation lever 7B to stop driving the first yarn gripping device 3 (or the second yarn gripping device 4), in spite of the rotation of the yarn gripping device driving cam 8B. On this occasion, the other stop lever is not driven, but only the second yarn gripping device 4 (or the first yarn griping device 3) is driven.

[0063] As shown in Figure 6, the cam shaft 8A is appropriately driven by separately provided driving means (not shown in the drawings) via a belt 1 F and a pulley 1G; the cam shaft 8A transmits a driving force required to drive the yarn gripping devices 3, 4. Each yarn gripping device is driven by the yarn gripping device driving cam 8B (8Ba, 8Bb) via the operation lever 7B (7Ba, 7Bb), and the yarn gripping device driving cam 8B is installed around the cam shaft 8A. Similarly, the yarn transferring device 6, comprising the yarn transferring lever 32 and the bunch lever 33, is driven by a yarn transferring device driving cam 8C (8Ca, 8Cb), installed around the cam shaft 8A, via the operation lever 7F (7Fa, 7Fb).

[0064] On this occasion, one of the selective driving devices ST (first selective driving device STa, second selective driving device STb), comprising the shaft 9A (9Aa, 9Ab) and the stop levers 9B (9Ba, 9Bb), 9D (9Da, 9Db), is driven in accordance with the preset program as previously described; the shaft 9A is rotatively driven by the driving cylinder 9C (9Ca, 9Cb) and the stop levers 9B (9Ba, 9Bb), 9D (9Da, 9Db) are installed on the opposite sides of the shaft 9A. That is, a change-over valve 14 provided in switching means 13 is driven to drive one of the yarn gripping devices and one of the yarn transferring devices 6.

[0065] That is, the change-over valve 14 is driven via the switching means 13 to supply compressed air to a pipe 15A shown by a solid line to project the one driving cylinder 9Cb, while withdrawing the other driving cylinder 9Ca, and this drives only the one second selective driving device STb and thus drives the second yarn gripping device 4. On the other hand, compressed air is supplied to a pipe 15B shown by a broken line to withdraw the one driving cylinder 9Cb, while projecting the other driving cylinder 9Ca, and this drives the other first selective driving device STa and thus drives the first yarn gripping device 3. The single change-over valve 14 is thus switched via the switching means 13 in accordance with the program preset in the machine body, and either the bunch winding forming means or the straight winding forming means is thus selected to form a desired wound yarn.

[0066] Now, the yarn transferring device 6 (6A, 6B) will be described with reference to Figures 7 and 8.

[0067] The yarn transferring device 6 (both 6A and 6B) is disposed at a tip portion of a link lever 7G, and the yarn transferring device 6 is actuated by driving the link lever 7G by the yarn transferring device driving cam 8C of the cam shaft 8A via the operation lever 7F. On this occasion, a cam follower 7J installed on the operation lever 7F is urged by the coil spring 7H to abut against a peripheral surface of the yarn transferring device driving cam 8C as in the case of the yarn gripping device 3.

[0068] The bunch lever 33 is installed at the tip portion of the link lever 7G via a bell crank 30 and a yarn transferring lever 32. When the link lever 7G is moved in the direction of arrow 7Ga, the bell crank 30 rotates in the direction of arrow 30a to rotate the yarn transferring lever 32 around a vertical shaft 60 in the direction of arrow 32a, and the urging force of the coil spring or the like correspondingly rotates a yarn hooking portion 33B of the bunch lever 33 in the direction of arrow 33a. The rotating yarn hooking portion 33B catches the yarn Y, and the bunch lever 33 stops at a position adjusted by a stopper 34 so that a guide 35 is located at a predetermined bunch winding position. The yarn transferring lever 32 further rotates against the urging force of the coil spring to cause the yarn catching portion 32B of the yarn transferring lever 32 to re-catch the yarn already caught by the yarn hooking portion 33B, thus regulating the yarn Y. Finally, the link lever 7G moves in a direction 7Gb along the shape of the yarn transferring device driving cam 8C to move the yarn transferring lever 32 in the direction of arrow 32b, and the caught yarn Y is then delivered to the guide 35 and guided to a predetermined position where it is wound.

[0069] Thus, to form a bunch winding portion, the yarn transferring lever 32 positions the supplying package-side yarn leading to the yarn gripping device 4D, between an end surface of the empty tube T and the tube holding member 11 E of the cradle 11 D as shown in Figure 10. The cradle 11 D is then closed to sandwich the yarn between the empty tube T and the holding member 11 E. The guide portion 35 of the bunch lever 33 locates the yarn at the position of a bunch winding portion BB.

[0070] As described above, the doffing device 1 for the automatic winder in accordance with the present invention has the bunch winding forming means BBA for forming a bunch winding portion around one end of the empty tube T, the straight winding forming means BAA for winding the yarn around the intermediate portion of the empty tube T, and the switching means 13 for selecting either the bunch winding forming means or the straight winding forming means to form a desired wound yarn. This makes it possible to carry out bunch winding for winding packages requiring bunch winding, while reliably winding the yarn end around the intermediate portion of the empty tube for winding packages not requiring bunch winding.

[0071] Figure 9 shows an example of an empty tube around which a straight winding portion has been formed and an empty tube around which a bunch winding portion has been formed. Figure 9A shows that the yarn Y is wound by winding a winding start yarn end around the intermediate portion of the empty tube T to form a straight winding portion BA. Figure 9B shows that the yarn Y is wound by winding a winding start yarn end around one end of the empty tube T to form a bunch winding portion BB. The empty tube may be either a cylindrical para-tube such as the one shown in the figures or a cone tube.

[0072] Thus, even to wind plural types of yarns under different winding conditions, the doffing device in accordance with the present invention can select and actuate the bunch winding forming means to carry out bunching on winding packages requiring bunch winding, while selecting and actuating the straight winding forming means to reliably wind the yarn end around the intermediate portion of the empty tube for winding packages not requiring bunch winding.

[0073] Thus, the automatic winder comprising the doffing device in accordance with the present invention can easily deal with both a yarn type requiring bunch winding and a yarn type that prefers straight winding to bunch winding, by presetting respective operation conditions. The present invention is thus suitable for producing multiple types of yarns in small amounts.

Claims

1. A doffing device for an automatic winder which unloads a full winding package while supplying an empty tube and which winds a supplying package-side yarn end around the empty tube to resume winding, the doffing device being characterized by comprising:

bunch winding forming means for forming a bunch winding portion around one end of the empty tube, straight winding forming means for winding a yarn around an intermediate portion of the empty tube, and switching means for selecting either the bunch winding forming means or the straight winding forming means.

2. A doffing device for an automatic winder according to Claim 1, characterized in that the straight winding forming means comprises a first yarn gripping device which cuts the yarn and grips a yarn end, a first yarn transferring device, a winding rotor including a yarn receiving member that receives a yarn end gripped by the yarn gripping device and a tube holding member, and a rotor swing arm that swings the winding rotor.

3. A doffing device for an automatic winder according to Claim 2, characterized in that the tube holding member of the winding rotor receives and holds a new empty tube from a chucker arm that grips and transfers the empty tube, and the yarn receiving member rotates a number of times around the tube holding member holding the empty tube, to form a straight winding portion in which the yarn is wound a given number of times.

4. A doffing device for an automatic winder according to Claim 3, characterized in that the chucker arm grips one empty tube housed in tube stocker that houses a plurality of empty tubes and delivers the empty tube to the tube holding member and which holds again the empty tube around which a straight portion has been formed and transfers the empty tube to a cradle position in a winding portion.

5. A doffing device for an automatic winder according to any one of Claims 1 to 4, characterized in that the bunch winding forming means comprises second yarn gripping device that cuts a yarn and grips a yarn end and a second yarn transferring device that guides the yarn end gripped by the second yarn gripping device, to a yarn bunch winding position.

6. A doffing device for an automatic winder according to Claim 5, characterized in that the switching means comprises one change-over valve that simultaneously controllably drives a first driving cylinder and a second driving cylinder in opposite directions, the first driving cylinder driving the first yarn gripping device and the yarn transferring device provided in the straight winding forming means, the second driving cylinder driving the second yarn gripping device and the second yarn transferring device provided in the bunch winding forming means.

Drawing