Yarn package changing apparatus and a yarn package changing method for a loom

Abstract: A yarn package changing method and an apparatus for carrying out the same, for use in combination with a loom which receives the weft yarn from a yarn package. The yarn package changing method carries out automatic yarn package changing operation through steps of removing an empty bobbin set in a yarn package changing position on a yarn package stand, by a yarn package transporting device, supplying a new yarn package to the yarn package stand by the yarn package transporting device, holding the leading end of the new yarn package at a predeter­ mined position by a leading end positioning device; and setting the new yarn package in a feeding position on the yarn package stand.

Description: BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a yarn package changing apparatus and a yarn package changing method for supplying a yarn package of weft yarn to a loom. DISCUSSION OF THE BACKGROUND The applicant for patent on the present invention has previously proposed an automatic weft yarn threading apparatus in J.P. Provisional Pub. (Kokai) No. 61-47849 (corresponding to U.S. Pat. No. 4,658,866). This previously proposed automatic weft yarn threading apparatus is capable of automatically restarting the loom by finding the leading end of the weft yarn of a new yarn package, unwinding the weft yarn from the new yarn package and threading the weft yarn on the loom when the loom is stopped due to the exhaustion of a yarn package presently supplying a weft yarn or upon the breakage of a weft yarn while the loom is in operation. This known technique enables a smooth and automatic supply package changing operation for changing the supply of a weft yarn from a yarn package supported on a yarn package stand for the supply of a weft yarn from a new package supported on the yarn package stand. However, the previously proposed yarn package changing apparatus is unable to automatically change a used yarn package for a new package and hence unable to achieve fully automated weft yarn supply operation. In this specification, "used yarn package" is the general designation of exhausted yarn packages, i.e., empty bobbins, and half used yarn packages having some amount of yarn and yet to be replaced with a new yarn package. Document EP-A-0 306 079 published on March 8, 1989, i.e after the priority dates of the present invention, discloses a yarn package changing apparatus for a loom, which receives a weft yarn via an automatic weft yarn threading device and a thread eye from a yarn package, for replacing a used yarn package by a new yarn package. In replenishing the loom with a new yarn package, it is essential to ensure finding the leading end of the weft yarn wound on the new yarn package and to introduce the leading end into the automatic weft yarn threading apparatus. To secure the precise weft yarn threading operation of the automatic weft yarn threading apparatus, one method employs a yarn transfer device disposed opposite to the automatic weft yarn threading apparatus, for positioning the leading end of the weft yarn near the automatic weft yarn threading apparatus in a predetermined shape to enable the automatic weft yarn threading apparatus to pull in the weft yarn. Another method employs a suction pipe having a flared inlet end which sucks the leading end of the weft yarn lying in a natural position on the circumference of the yarn package and introduces the leading end to the automatic weft yarn threading apparatus. The reliability of the former method in threading a weft yarn is higher than that of the latter method, because the former method grips the leading end of the weft yarn mechanically for positive introduction of the leading end to the automatic weft yarn threading apparatus. SUMMARY OF THE INVENTION Accordingly, it is the principal object of the present invention to provide an apparatus and a method capable of automatically changing a used yarn package for a new yarn package to supply a weft yarn to a loom. More specifically, it is a first object of the present invention to provide a yarn package transporting device for removing a used yarn package and supplying a new yarn package to a yarn package stand with the leading end of the weft yarn pulled out. It is a second object of the present invention to provide a yarn package stand capable of holding a new yarn package in a yarn feeding position for smooth feeding of the weft yarn to the loom and to provide a yarn package changing method capable of surely and quickly changing a used yarn package for a new yarn package. It is a third object of the present invention to provide a leading end positioning device capable of setting the leading end of a weft yarn unwound from a new yarn package at a predetermined position to introduce the leading end to the automatic weft yarn threading apparatus of a loom. BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: Figure 1 is a schematic perspective view showing the general structure of a yarn package changing apparatus embodying the present invention; Figure 2 is a side elevational view of a yarn package transporting device and a yarn package stand embodying the present invention; Figure 3 is a partially cutaway side elevational view of a yarn package transporting device embodying the present invention; Figure 4 is a plan view of assistance in explaining the operation of a yarn package transporting device and a yarn package stand embodying the present invention; Figure 5 is a perspective view of a leading end clamping device included in the yarn package transporting device of Fig. 3; Figure 6 is a side elevational view of assistance in explaining a leading end positioning device embodying the present invention; Figures 7 and 8 are illustrations of assistance in explaining the operation of a leading end positioning device; Figure 9 is a perspective view of assistance in explaining a leading end positioning device in another embodiment according to the present invention; Figure 10 is a view of assistance in explaining an essential portion of the yarn package stand of Fig. 2; Figure 11 is a sectional view taken on line XI-XI in Fig. 10; Figures 12 to 14 are perspective views of assistance in explaining a yarn package stand in another embodiment according to the present invention; Figure 15 is a side elevational view of assistance in explaining a yarn package stand in a further embodiment according to the present invention; and Figure 16 is a perspective view of the yarn package holding unit shown in Fig. 15. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Typical embodiments of the present invention will be described hereinafter with reference to the accompanying drawings, in which like or corresponding parts are denoted by the same reference characters. Referring to Fig. 1, a yarn package changing apparatus comprises a yarn package transporting device 50, first and second yarn package stands 10, only one of which is shown, and a leading end positioning device LS. The yarn package changing apparatus changes a used yarn package (hereinafter designated as "empty bobbin") Y₀ supported on the yarn package stand 10 for a new yarn package Y. Indicated at L₁ is the suction pipe of an automatic weft yarn threading device provided in combination with a loom. The suction pipe L₁ sucks the leading end Y₁ of the new yarn package Y supported on the yarn package stand 10 to feed the weft yarn from the new yarn package Y to the loom. The loom is a shuttleless loom, such as an air jet loom or a water jet loom. Referring to Fig. 3, the yarn package transporting device 50 has, as principal units, a bobbin holding unit 54 and a pinch unit 55. The bobbin holding unit 54 and the pinch unit 55 are provided respectively on a box-shaped case attached to the extremity of a swing arm 53, and an auxiliary arm 53b extending from the side wall of the box-shaped case 54h. The swing arm 53 is supported on a post 52 both for vertical movement along the post 52 and for swing motion on the post 52. As shown in Fig. 3, the bobbin holding unit 54 is held for vertical movement on a slider 54f vertically slidably engaging a vertical slide base 53a attached to the extremity of the swing arm 53; that is, the slider 54f is a base member for holding the bobbin holding unit 54 and is vertically slidable on the slide base 53a. The lowermost position of the slider 54f on the slide base 53a is limited by a stopper 53e provided at the lower end of the slide base 53a. The bobbin holding unit 54 comprises a pair of gripping fingers 54a supported for swing motion opposite to each other, a pneumatic cylinder actuator 54b for operating the pair of gripping fingers 54a, and a motor 54d for rotatively driving the gripping fingers 54a. The base ends of the gripping fingers 54a are connected through link plates 54k to the actuating rod 54b₂ of the pneumatic cylinder actuator 54b. The gripping fingers 54a are pivotally supported at the middle portions thereof by pins 54m on a holder case 54n. The free ends of the gripping fingers 54a are bent inward in the shape of a hook conforming to the shape of the ring-shaped gripping head Yb₂ of the bobbin Yb of the yarn package Y. The holder case 54n is provided on the lower surface thereof with a stepped protrusion 54g fitting the bore of the bobbin of the yarn package Y. A holding member 54p for holding both the pneumatic cylinder actuator 54b and the motor 54d is provided with sensors 54p₁ to detect the arrival of the bobbin holding unit 54 at the uppermost position and the lowermost position through the detection of the upper end of the slide base 53a. The holding member 54p is provided internally with a spring 54c to bias a rod 54b₂ constantly upward. The sensors 54p₁ also detect the extension of the spring 54c to the limit of extension and the contraction of the same to the limit of contraction respectively. The motor 54d held on the holding member 54p drives the gripping fingers 54a through a belt 54e for rotation in a horizontal plane. A shaft 54q extending upward from the upper end of the holder case 54n is journaled for rotation on the holding member 54p. The actuating rod 54b₂ of the pneumatic cylinder actuator 54b penetrates the shaft 54q axially. The belt 54e is wound round a belt pulley fixed to the upper end of the shaft 54q. The pneumatic cylinder actuator 54b and the motor 54d are contained entirely in the box-shaped case 54h, and the auxiliary arm 53b is fixed at one end thereof to the side wall of the case 54h. A suspending rod 53c is fixed at the upper end thereof to the extremity of the auxiliary arm 53b, and a base plate 53d is fixed to the lower end of the suspending rod 53c. The pinch unit 55 and a guide unit 56 are attached to the lower surface of the base plate 53d so as to extend downward. The pinch unit 55 is more remote from the bobbin holding unit 54 than the guide unit 56. The pinch unit 55 is moved vertically by a pneumatic cylinder actuator 55a. The bobbin holding unit 54, the pinch unit 55 and the guide unit 56 are disposed in alignment with a straight line passing the axis of swing motion of the swing arm 53. Referring to Fig. 5, the pinch unit 55 has a pair of pinching members 55c which are moved away from and toward each other by a pneumatic cylinder actuator 55b. The guide unit 56 has a pair of guide members 56b which are moved away from and toward each other by a pneumatic cylinder actuator 56a. The pinching members 55c are moved toward each other so that the respective parallel lower portions are pressed against each other to grip the leading end Y₁ of the weft yarn. The respective lower portions of the guide members 56b are bent obliquely inward so that the lower portions form a shape resembling the letter V when the guide members 56b are pressed against each other to hold the leading end Y₁ therebetween. When the actuating rod of the pneumatic cylinder actuator 55a is retracted, the pinch unit 55 and the guide unit 56 are substantially on the same level and, preferably, the extremities of the pinching members 55c and those of the guide members 56b are positioned below the level of the extremities of the gripping fingers 54a of the bobbin holding unit 54 by a distance corresponding to approximately half the height of the yarn package Y to be transported. The pinching unit 55 may comprise a suction pipe capable of sucking the leading end Y₁. As shown in Fig. 3, the yarn package Y to be transported has yarn layers Y 1a formed by winding a weft yarn around a bobbin Yb provided with flanges Yb₁ at the opposite ends thereof. The gripping head Yb₂ is formed at the upper end of the bobbin Yb. As shown in Fig. 1, the leading end of the weft yarn of the yarn package Y is unwound from the yarn package Y before transporting the yarn package Y to the weft yarn feeding position by a length suitable for the pinching unit 55 to grip the leading end, and the leading end is held in a horizontal position by a yarn holding device 57. The yarn holding device 57 has posts 57a provided with elastic yarn holding members and threading grooves. In transporting the yarn package Y, the yarn package transporting device 50 is set in a standby state by moving the swing arm 53 to an upper position, where the gripping fingers 54a of the bobbin holding unit 54 is on a level above that of the upper end of the bobbin Yb of the yarn package Y, as indicated by imaginary lines in Fig. 2 by a known lifting mechanism, such as a cylinder actuator, opening the gripping fingers 54a of the bobbin holding unit 54 as indicated by continuous lines in Fig. 3, opening the pinching members 55c of the pinch unit 55, and opening the guide members 56b of the guide unit 56. In the standby state, the actuating rod of the pneumatic cylinder actuator 55a is retracted so that the pinch unit 55 and the guide unit 56 are held on the same level. The swing arm 53 is swung to position the bobbin holding unit 54 so that the bobbin holding unit 54 and the yarn package Y are in coaxial alignment, and then the swing arm 53 is moved downward. As the swing arm 53 moves downward, the stepped protrusion 54g of the bobbin holding unit 54 is received in the bore of the bobbin Yb of the yarn package Y, and further downward movement of the bobbin holding unit 54 together with the swing arm 53 is stopped. As the swing arm moves further downward, the bobbin holding unit 54 moves upward together with the slider 54f relative to the slide base 53a fixed to the swing arm 53. Upon detection of the upper end of the slide base 53a by the sensor 54p₁, downward movement of the swing arm 53 is stopped. Since the slider 54f, and hence the bobbin holding unit 54, is able to move upward relative to the slide base 53a fixed to the swing arm 53, control operation for stopping the swing arm 53 need not be very accurate and there is no possibility that the yarn package Y is exposed to an excessively high pressure. Then, the actuating rod 54b₂ of the pneumatic cylinder actuator 54b is retracted to grip the bobbin Yb of the yarn package Y with the gripping fingers 54'a as indicated by imaginary lines in Fig. 3. That is, upward movement of the actuating rod 54b₂ of the pneumatic cylinder actuator 54b turns the gripping fingers 54a on the pins 54m through the link plates 54k so that the lower ends of the gripping fingers 54a move toward each other. Therefore, the hooks formed at the lower ends of the gripping fingers 54a engage the gripping head Yb₂ of the bobbin Yb of the yarn package Y to hold the yarn package Y when the actuating rod 54b₂ of the pneumatic cylinder actuator 54b is retracted. Since the actuating rod 54b₂ is biased constantly upward, namely, in the direction of retraction, there is no possibility that the gripping fingers 54a are disengaged accidentally from the gripping head Yb₂ and the yarn package Y falls off the bobbin holding unit 54, even if the air pressure applied to the active chamber of the pneumatic cylinder actuator is removed after the gripping fingers 54a have gripped the gripping head Yb₂ of the bobbin Yb. When the yarn package Y is held by the bobbin holding unit 54, the pinch unit 55 is positioned at a position where the pinching members 55c are able to pinch the leading end Y₁ extending horizontally from the yarn package Y, and the guide unit 56 is positioned at a position where the guide members 56b are able to receive the leading end Y₁ therebetween. Then, the pneumatic cylinder actuators 55b and 56a are actuated to close the pinching members 55c and the guide members 56b to pinch the leading end Y₁ with the pinching members 55c and to close the guide members 56b in a shape resembling the letter V. Then, the swing arm 53 is elevated along and swung on the post 52 to transport the yarn package Y to a desired position with the leading end Y₁ of the yarn package Y held ready to be threaded. The motor 54d is actuated after lifting up the yarn package Y by elevating the swing arm 53 to stretch the leading end Y₁ in a straight line between the yarn package Y and the pinch unit 55 under a fixed tension. That is, the bobbin holding unit 54 is rotated through the belt 54e by the motor 54d to rotate the yarn package Y in a winding direction. The tension of the leading end Y₁ can be adjusted to a fixed value by pinching the leading end Y₁ so that the leading end Y₁ is allowed to slip relative to the pinching fingers 55c when a tension exceeding the fixed tension is applied to the leading end Y₁. The yarn package transporting device 50 transports the yarn packages Y to the yarn package stands 10. As shown in Fig. 2, each of the yarn package stands 10 includes a post 11, a rotary shaft 12 supported coaxially with the post 11, an arm 13 journaled on the upper end of the rotary shaft 12 so as to extend perpendicularly to the rotary shaft 12, and a yarn package support peg 14 attached to one end, i.e., the free end, of the arm 13. The yarn package support peg 14 has a support part 14a of an increased diameter to be received in the bore of the bobbin Yb of the yarn package Y. A flange 14b is attached to the lower end of the support part 14a to receive the bobbin Yb thereon. As shown in Fig. 10, a recess 11a is formed in the middle portion of the post 11. A bevel gear 12a is attached to the lower end of the rotary shaft 12 projecting into the recess 11a. A pin 15a has one end fixed to the lower end of the rotary shaft 12, and the other end pivotally joined to the lower end of a pneumatic cylinder actuator 15. The extremity of the actuating rod of the pneumatic cylinder actuator 15 is joined pivotally to a lever 13a projecting from the other end of the arm 13. A bevel gear 16a is rotatably supported in the recess 11a so as to engage the bevel gear 12a. The bevel 16a is rotatably driven by a motor 16 (Fig. 2) to turn the rotary shaft 12 on the post 11. A stopper 12b is attached to the lowermost end of the rotary shaft 12. As shown in Fig. 11, stopper bolts 11b are fixed to the post 11 so as to engage the stopper 12b at the opposite limits of turning motion of the rotary shaft 12 to define the turning range of the rotary shaft 12. The rotary shaft 12 can be turned through the bevel gears 16a and 12a by the motor 16 in the directions indicated by the arrows in Fig. 10 to swing the arm 13 in a horizontal plane. The arm 13 is swung about its axis by operating the pneumatic cylinder actuator 15 to tilt the yarn package support peg 14 at a desired inclination within a vertical plane including the axis of the yarn package support peg 14. The arm 13 is turned about its axis by the pneumatic cylinder actuator 15 to set the support part 14a in an upright position as indicated by broken lines in Fig. 2, the rotary shaft 12 is turned to one of the limits of turning motion to position the support part 14a directly below and coaxially with the bobbin holding unit 54, and then the swing arm 53 is lowered and the new yarn package Y held by the bobbin holding unit 54 is released to support the new yarn package Y on the support part 14a with the support part 14a received in the bore of the bobbin Yb of the new yarn package Y. The empty bobbin Y₀ is removed from the support part 14a by the yarn package transporting device 50 before putting the new yarn package Y on the support part 14a. The yarn package changing position is common to the first and second yarn package stands 10. In transporting the yarn package Y from the yarn package transporting device 50 to the yarn package stand 10, the leading end Y₁ is transported from the pinch unit 55 to the leading end positioning device LS. Referring to Figs. 1, 4 and 6, a tubular positioning member L₂ is disposed fixedly near the suction pipe L₁ of the automatic weft yarn threading device combined with the loom. A notch L₂a is formed in the extremity of the positioning member L₂ to hold the leading end Y₁. A swing suction pipe L₃ having a suction opening L₃a for sucking the free portion of the leading end Y₁ therethrough is disposed under the positioning member L₂. Preferably, a cutter L₄ for cutting the leading end Y₁ in an appropriate length is provided between the positioning member L₂ and the suction pipe L₃. In Fig. 6, the yarn package Y held by the bobbin holding unit 54 of the yarn package transporting device 50 has been put on the support part 14a of the yarn package support peg 14 of the yarn package stand 10. In this state, the auxiliary arm 53b is positioned immediately above the positioning member L₂, the leading end Y₁ is extended over the positioning member L₂ through the guide unit 56 between the yarn package Y and the pinch unit 55. The actuating rod of the pneumatic cylinder actuator 55a is extended to lower the pinch unit 55 pinching the leading end Y₁ to a position indicated at 55', so that part of the leading end Y₁ is positioned near the suction opening L₃a of the suction pipe L₃. Then, the pneumatic cylinder actuator 55b is actuated to open the pinching members 55c, so that the leading end Y₁ is sucked into the suction pipe L₃. Then, the suction pipe L₃ is moved to a position L₃' to put part of the leading end Y₁ in the notch L₂a of the positioning member L₂. In transferring the leading end Y₁ to the suction pipe L₁ of the automatic weft yarn threading device, cutting the free portion of the leading end Y₁ at a position between the positioning member L₂ and the suction pipe L₃ facilitates transferring the leading end Y₁ to the suction pipe L₁ of the automatic weft yarn threading device by a transfer rod. Referring to Fig. 9 showing a leading end positioning device LS in another embodiment according to the present invention, the leading end positioning device LS employs a retractable guide member L₂d having a shape resembling the letter Y to guide the leading end Y₁ surely to the notch L₂a of a positioning member L₂. The guide member L₂d may be substituted by a guide member L₂ as shown in Fig. 7 having bifurcate guide lips L₂b at the extremity thereof. The positioning member L₂ may be such as movable toward and away from the suction pipe L₁ of the automatic weft yarn threading device. The yarn package changing operation of the yarn package transporting device 50, the leading end positioning device LS and the two yarn package stands 10 will be described hereinafter. New yarn packages Y and empty bobbins Y₀ are stacked up respectively at two stacking positions. The swing arm 53 positions the bobbin holding unit 54 directly above the stacking positions. Three guide posts 51a are set upright around each of the stacking positions so as to surround the new yarn packages Y and the empty bobbins Y₀ stacked up at the stacking positions to keep the respective stacks of new yarn packages Y and empty bobbins Y₀ securely in place. As shown in Fig. 4, the yarn holding device 57 is disposed beside the stacking position for new yarn packages under the extension of the swing arm 53. As shown in Fig. 1, the leading ends Y₁ of the new yarn packages Y are extended under tension between the two posts 57a of the yarn holding device 57 so as to be picked up. Suppose that a new yarn package Y in a feed position on the first yarn package stand 10 is an active yarn package (a yarn package indicated by continuous lines in Fig. 4), namely, a yarn package currently feeding a weft yarn to the loom, and the other yarn package (a yarn package indicated by imaginary lines in Fig. 4) in a feed position on the second yarn package stand 10 is a standby yarn package. Upon the exhaustion of the active yarn package Y or the interruption of yarn feed by yarn breakage during the weaving operation of the loom L, the automatic weft yarn threading device changes the weft yarn of the active yarn package for that of the standby yarn package, and then the loom L is restarted automatically. The leading end Y₁ of the standby yarn package Y is extended via the notch L₂a of the positioning member L₂ between the standby yarn package Y and the swing suction pipe L₃ staying at the retracted position. In introducing the leading end Y₁ of the weft yarn of the standby yarn package Y into the loom L by the automatic weft yarn threading device, the unnecessary portion of the leading end Y₁ is cut off by the cutter L₄. On the other hand, the arm 13 of the first yarn package stand 10 swings about the axis of the rotary shaft 12 and turns about its axis to move the empty bobbin Y₀ to the yarn package changing position and to set the empty bobbin Y₀ in an upright yarn package changing position. Then, the yarn package transporting device 50 transports the empty bobbin Y₀ from the first yarn package stand 10 to the used yarn package stacking position on the base 51 of the yarn package transporting device 50 through steps of elevating the swing arm 53, swinging the swing arm 53 to position the bobbin holding unit 54 directly above the empty bobbin Y₀ on the first yarn package stand 10, lowering the swing arm 53 to make the bobbin holding unit 54 engage the gripping head Yb₂ of the bobbin of the empty bobbin Y₀, holding the empty bobbin Y₀ by the bobbin holding unit 54, elevating the swing arm 53 to remove the empty bobbin Y₀ from the yarn package support peg 14, swinging the swing arm 53 to position the used empty bobbin Y₀ held by the bobbin holding unit 54 directly above the stack of empty bobbins Y₀ on the base 51 of the yarn package transporting device 50, lowering the swing arm 53 to place the empty bobbin Y₀ on top of the stack of empty bobbins Y₀, and releasing the empty bobbin Y₀ from the bobbin holding unit 54. Subsequently, the yarn package transporting device 50 elevates the swing arm 53, swings the swing arm 53 in the opposite direction as shown in Fig. 4 to position the bobbin holding unit 54 directly above the stack of new yarn packages Y, lowers the swing arm 53, and grips the uppermost new yarn package Y by the bobbin holding unit 54. Simultaneously with the yarn package gripping operation of the bobbin holding unit 54, the pinching unit 55 pinches the leading end Y₁ extending from the new yarn package Y, and the guide unit 56 closes the guide members 56b under the leading end Y₁. Then, the swing arm 53 is elevated and swung again to position the bobbin holding unit 54 directly above the common yarn package changing position. The bobbin holding unit 54 is turned by the motor 54d in a winding direction after the pinching unit has pinched the leading end Y₁ to extend the leading end Y₁ in a predetermined taut state. Subsequently, the swing arm 53 is lowered to mount the new yarn package Y on the yarn package support peg 14 placed in an upright position. Simultaneously, the actuating rod of the pneumatic cylinder actuator 55a is extended to move the pinching unit 55 downward to the position 55' indicated by imaginary lines in Fig. 6, so that the leading end Y₁ is bent at the extremity of the guide unit 56 and is moved to a position below the suction pipe L₃ positioned at the front standby position passing near the respective extremities of the positioning member L₂ and the suction pipe L₃. In lowering the pinching unit 55, the bobbin holding unit 54 is turned by the motor 54d so that the weft yarn is unwound properly from the new yarn package Y as the pinching unit 55 is moved downward. Then, the suction pipe L₃ becomes active, the pinching unit 55 releases the leading end Y₁ and the guide members 56b of the guide unit 56 are opened to suck the leading end Y₁ into the suction pipe L₃. Then, the suction pipe L₃ is moved to the retracted position. Consequently, the leading end Y₁ is bent by the positioning member L₂ and is extended taut between the new yarn package Y and the suction pipe L₃ as indicated by an imaginary line in Fig. 6. The notch L₂a of the positioning member L₂ positions the leading end Y₁ accurately. Then, the bobbin holding unit 54 releases the new yarn package Y, and then the swing arm 53 is elevated to separate the bobbin holding unit 53 from the new yarn package Y. After the new yarn package Y has been mounted on the yarn package support peg 14 of the first yarn package stand 10, the rotary shaft 12 is reversed and the arm 13 is swung to position the new yarn package Y at the common yarn package changing position in a weft yarn feeding position. Thus, the new package Y is reserved on the first yarn package stand 10 as a standby yarn package for the next use. Since the leading end Y₁ of the new yarn package Y is extended in a taut state by the suction of the suction pipe L₃ during the operation for changing the position of the new yarn package Y, the leading end Y₁ never falls off the notch L₂a of the positioning member L₂. Even if the length of the portion of the leading end Y₁ extending between the new yarn package Y and the suction pipe L₃ changes due to the variation of the distance between the new yarn package Y and the positioning member L₂ in changing the position of the new yarn package Y, the variation in the length can smoothly be absorbed by a portion of the leading end Y₁ pulled out from or sucked into the suction pipe L₃. The yarn package stands 10 may be substituted by yarn package stands as shown in Figs. 12 to 15. Fig. 12 shows a pair of yarn package stands 10 in a second embodiment according to the present invention. The yarn package stands 10 shown in Fig. 12 are used when the yarn package support pegs 14 of the yarn package stands 10 need not be moved to a common yarn package changing position for yarn package changing operation. Each yarn package stand 10 has an arm 13 provided with the yarn package support peg 14 at one end thereof. The arm 13 is turned simply about its axis between a position where the yarn package support peg 14 is placed in an upright position, and a position where the same is placed in a tilted position in which the yarn package support peg 14 is directed toward the weft yarn inlet L₁a of the suction pipe L₁ of the automatic weft yarn threading device. A bend is formed at the extremity of a lever 13a attached to the other end of the arm 13. This yarn package stand 10 is used suitably for supporting a cone as shown in Fig. 12. An overhead traveling yarn package transporting device 50 as shown in Fig. 12 is used in combination with the yarn package stands 10. The traveling yarn package transporting device 50 is suspended from a trolley 59 which travels along an overhead guide rail 59a. The traveling yarn package transporting device 50 has a horizontal arm 53 instead of the swing arm 53. The arm 53 does not swing and instead is moved vertically by a known lifting mechanism, not shown. A bobbin holding unit 54 included in the traveling yarn package transporting device 50 employs an elastic bag instead of the gripping fingers 54a to hold a yarn package Y. In lifting up a yarn package Y, the elastic bag is inserted in the bore of the bobbin of the yarn package Y, compressed air is supplied into the elastic bag to inflate the same, and then the inflated elastic bag is elevated to lift up the yarn package Y. In releasing the yarn package Y, the air is discharged from the inflated elastic bag to allow the inflated elastic bag to reduce its diameter. An auxiliary arm 53b is extended from a rotary member 53e which is turned about a vertical axis by a motor 53f to swing the auxiliary arm 53b in a horizontal plane so that a pinching unit 55 and a guide unit 56 suspended from the auxiliary arm 53b are placed directly above a positioning member L₂. In removing an empty bobbin Y₀ from the yarn package stand 10, the traveling yarn package transporting device 50 is stopped upon the arrival of the bobbin holding unit 54 at a position directly above the yarn package stand 10, the horizontal arm 53 is lowered to a predetermined position, the lever 13a is turned downward by extending the actuating rod of an pneumatic cylinder actuator 58 to set the empty bobbin Y₀ supported on the yarn package support peg 14 of the yarn package stand 10 in an upright position as indicated by imaginary lines in Fig. 12, the actuating rod of the pneumatic cylinder actuator 58 is disengaged from the lever 13a by suitable means, such as turning the actuating rod, the horizontal arm 53 is lowered further to insert the elastic bag in the bore of the empty bobbin Y₀, the elastic bag is inflated, and then the horizontal arm 53 is elevated to remove the empty bobbin Y₀ from the yarn package support peg 14. Then, the traveling yarn package transporting device 50 is moved to transport the empty bobbin Y₀ to an empty bobbin storing place. In putting a new yarn package Y on the yarn package support peg 14 of the yarn package stand 10, the yarn package transporting device 50 picks up a new yarn package Y at a new yarn package storing place, carries the new yarn package Y with the leading end of the weft yarn of the new yarn package Y held by the pinching unit 55 to a position directly above the yarn package support peg 14 placed in an upright position, and puts the new yarn package Y on the yarn package support peg 14 of the yarn package stand 10 simply by lowering the horizontal arm 53. Then, the auxiliary arm 53b is swung in a horizontal plane to position the pinching unit 55 near and above the positioning member L₂ as indicated by imaginary lines in Fig. 12. Then, the leading end Y₁ of the new yarn package Y is extended via the notch L₂a of the positioning member L₂ between the new yarn package Y and a suction pipe L₃ by the same procedure as that employed in positioning the leading end by the aforesaid yarn package transporting device 50. Then, the lever 13a is turned upward by the pneumatic cylinder actuator 58 to set the yarn package support peg 14 supporting the new yarn package Y in the feeding position. In removing an empty bobbin Y₀ from the other yarn package support stand 10 and in putting a new yarn package Y on the same, the yarn package transporting device 50 is moved to a position corresponding to the other yarn package stand 10. Thus, the yarn package support pegs 14 of the yarn package stands 10 need not be positioned at a common yarn package changing position. A yarn package stand 10 in a third embodiment according to the present invention is shown in Fig. 13. This yarn package stand 10 comprises a post 11, a rotary block 28 rotatably supported on the post 11, three radial arms 13 radially extending from the rotary block 28, three yarn package support pegs 14 joined to the extremities of the radial arms 13 by hinge joints 14c. respectively, a peg operating mechanism 17 comprising a rack 17a supported on top of the post 11, and three pinions 17b interlocked respectively with the hinge joints 14c, and a rotating mechanism 18 comprising a motor 18a, a driving gear 18b fixed to the output shaft of the motor 18a, a driven gear 18c engaging the driving gear 18b, coaxially connected to the rotary block 28 and provided with recesses 18f formed in one surface thereof at equal angular intervals, and a positioning pin 18e capable of elastically engaging the recess 18f. The rotary block 28 is turned at equal angular intervals of 120° to index the radial arms 13 at predetermined positions including a position where the radial arms 13 are set in an upright position. The rotary block 28 is stopped at the predetermined angular positions by the engagement of the positioning pin 18e with the recesses 18f formed in the driven gear 18c. When each arm 13 is set in an upright position, the rack 17a engages and drives the pinion 17b to set the yarn package support peg 14 in an upright position as indicated by imaginary lines in Fig. 13. When the arm 13 is in a position other than the upright position, the yarn package support peg 14 is in a feed position in which the yarn package support peg 14 is directed toward the weft yarn inlet L₁a of the suction pipe L₁ of the automatic weft yarn threading device. A traveling yarn package transporting device, not shown, to be used in combination with this yarn package stand 10 is substantially the same in construction as that used in combination with the yarn package stands 10 in the second embodiment, except that the horizontal arm 53 is swingable in a horizontal plane and the pneumatic cylinder actuator 58 need not be provided. Desirably, the yarn package stand 10 is provided with three leading end positioning units, not shown, each provided with a positioning member L₂, not shown, capable of being moved toward and away from the suction pipe L₁ of the automatic weft yarn threading device. The yarn package stand 10 may be provided with no leading end positioning unit, and may be used in combination with a suction pipe L₂, not shown, having a funnelform inlet end entirely covering the yarn package supported on the yarn package support peg 14. Fig. 14 shows a yarn package stand 10 in a fourth embodiment according to the present invention. This yarn package stand 10 comprises a post 11, a rotary block 28 rotatably supported on the post 11, three radial arms 13 radially extending from the rotary block 28 at equal angular intervals, and three yarn package support pegs 14 joined respectively to the respective extremities of the radial arms 13. The radial arms 13 are swingable on the rotary block 28. The yarn package support pegs 14 are swingable on the extremities of the radial arms 13. When the radial arm 13 is positioned at a yarn package changing position as indicated by imaginary lines in Fig. 15, the yarn package support peg 14 is set in a yarn package changing position. A traveling yarn package transporting device 50, not shown, to be used in combination with the yarn package stand 10 travels horizontally to deliver a new yarn package, not shown, to the yarn package support peg 14 set in the yarn package changing position. Fig. 15 shows a yarn package stand 10 in a fifth embodiment according to the present invention. This yarn package stand 10 comprises a post 11, a frame 19a having a shape resembling the letter U, fixed to the upper end of the post 11, and having opposite upright base members, a pair of base plates 19b attached respectively to the upright base members of the frame 19a, and a pair of yarn package support units 20 detachably mounted respectively on the base plates 19b, and each comprising a base plate 20a, a pair of brackets 22a obliquely extending from the front surface of the base plate 20a in opposite directions, and yarn package support pegs 14 attached respectively to the respective extremities of the brackets 22a. Fig. 16 shows an exemplary means for detachably mounting the yarn package support unit 20 on the corresponding base plate 19b. As shown in Fig. 16, a dovetail groove 19c is formed in the base plate 19b, and a dovetail 20c fitting the dovetail groove 19c is formed in the backside of the base plate 20a of the yarn package support unit 20. Knobs 20b are formed respectively at the upper and lower ends of the base plate 20a. The gripping fingers 54a of the bobbin holding unit 54 of a yarn package transporting device 50 grips the knob 20b in removing the yarn package support unit 20 from the base plate 19b and transporting the same. As shown in Fig. 16, the yarn package support pegs 14 are positioned so that the center axis K of the yarn package support pegs 14 intersect each other at a point A positioned at a set distance d from a perpendicular CL to the front surface of the base plate 20a, passing the center G of the base plate 20a, and approximately on the center axis of the weft yarn inlet opening of the automatic weft yarn threading device to enable the weft yarns of the yarn packages supported on the yarn package support pegs 14 to be unwound smoothly. The bobbin holding unit 54 of the yarn package transporting device 50 is movable both horizontally and vertically to facilitate removing the yarn package support unit 20 from and putting the same on the base plate 19b. The yarn package transporting device 50 employs a swingable auxiliary arm 53b holding a pinching unit 55. The swingable auxiliary arm 53b swings to transfer the leading end Y₁ of a yarn package Y supported on the yarn package support unit 20 to a leading end positioning member L₂ in the same manner as that employed in the foregoing embodiments. Preferably, the trailing end of one of the two yarn packages supported on the yarn package support unit 20 and the leading end of the other yarn package are tied together to feed the weft yarn successively from both the yarn packages. The yarn package stand 10 provided with the two yarn package support units 20 reduces yarn package changing frequency. The use of the yarn package transporting device 50 in combination with the yarn end positioning device enables automatic yarn package changing operation. The yarn package transporting device 50 thus constructed changes empty bobbins efficiently and surely for new yarn packages, and the leading end of the new yarn package can accurately be taken to the leading end positioning device by the pinching unit and the guide unit. The yarn package stand holds the yarn package in a feeding position to feed the weft yarn to the loom without hindrance. The leading end positioning device positions successively and accurately the leading ends of yarn packages to be used successively at the predetermined position to ensure the weft yarn threading operation of the automatic weft yarn threading device, so that the lost weaving time necessary for yarn package changing operation is reduced to the least extent. The yarn package changing apparatus comprising the yarn package transporting device, the yarn package stand or stands, and the leading end positioning device fully enables automatic yarn package changing operation on the loom. Furthermore, the use of the yarn package stand having the yarn package support units for supporting yarn packages eliminates problems in changing the bobbin holding unit when the yarn packages are changed for those formed on bobbins different from those of the former yarn packages.

Claims: A yarn package changing apparatus for a loom which receives a weft yarn through an automatic weft yarn threading device (L₁) from a yarn package (Y), for replacing an empty bobbin (Y₀) by a new yarn package (Y), comprising a yarn package stand device (10) including means (11 - 16) for holding said yarn package (Y) in a feeding position to feed said weft yarn to said automatic weft yarn threading device (L₁), a yarn package transporting device (50) including means for mounting said new yarn package (Y) on and removing said used yarn package (Y₀) from said yarn package stand device (10), said means comprising a bobbin holding unit (54) for holding said yarn package (Y), and a pinching unit (55) for pinching the leading end (Y₁) of said yarn package (Y) held by said bobbin holding unit (54), said pinching unit (55) being movable relative to said bobbin holding unit (54) for conveying the pinched leading end (Y₁) to a threading position of said automatic weft yarn threading device (L₁), and a leading end positioning device (LS) for holding said leading end (Y₁) of said new yarn package (Y) mounted on said yarn package stand device (10) at a predetermined position opposite said automatic weft yarn threading device (L₁). An apparatus according to claim 1, characterized in that said bobbin holding unit (54) is provided with a plurality of gripping fingers (54a) operated by a cylinder actuator (54b) for gripping operation, wherein said bobbin holding unit (54) is driven for rotation via a driving belt (54e) by a motor (54d). An apparatus according to claim 1 or 2, characterized in that said pinching unit (55) is connected to a cylinder actuator (55a) connected to an auxiliary arm (53b) which is connected to said bobbin holding unit (54), wherein a guide unit (56) having guide members (56b) capable of being joined together and spaced apart is provided in the proximity of said pinching unit (55) on said auxiliary arm (53b). An apparatus according to claim 3, characterized in that said auxiliary arm (53b) is held at one end thereof by a case (54h) holding said bobbin holding unit (54). An apparatus according to one of the preceding claims, characterized in that said leading end positioning device (LS) comprises a positioning member (L₂) provided at the extremity thereof, having a notch (L 2a ) through which said leading end (Y₁) extends, and a swingable suction pipe (L₃) disposed in the proximity of said positioning member (L₂). An apparatus according to claim 5, characterized in that a cutter (L₄) for cutting said leading end (Y₁) at a predetermined length is disposed between said positioning member (L₂) and said swingable suction pipe (L₃). An apparatus according to claim 5 or 6, characterized in that a yarn guide (L 2d ) of a shape resembling the letter Y and capable of being advanced and retracted in the direction of the axis of said positioning member (L₂) is provided on the side of said yarn package transporting device (50) with respect to said positioning member (L₂). An apparatus according to one of the preceding claims, characterized in that said yarn package stand device (10) includes yarn package support pegs (14), each for supporting one yarn package (Y) and capable of being set in a feeding position for feeding yarn from said yarn package (Y) supported thereon, and in a yarn package changing position for changing said yarn package (Y). An apparatus according to claim 8, characterized in that said yarn package stand device comprises a pair of yarn package stands (10) each having a post (11), a rotary shaft (12) coaxially supported on said post (11), an arm (13) which is rotatably supported at one end thereof on the upper end of said rotary shaft (12) for rotation about its axis perpendicular to that of said rotary shaft (12), and which is provided at the other end thereof with said yarn package support peg (14), and a cylinder actuator (15) for turning said arm (13) about its axis. An apparatus according to claim 8, characterized in that said yarn package stand device comprises a pair of yarn package stands (10) each having a post (11), an arm (13) rotatably supported on the upper end of said post (11) with its axis perpendicular to that of said post (11), said yarn package support peg (14) being fixedly attached to one end of said arm (13) with its axis intersecting that of said arm (13), and a lever (13a) to be operated by a cylinder actuator (58) provided on said yarn package transporting device (50), fixedly joined to the other end of said arm (13). An apparatus according to claim 8, characterized in that said yarn package stand device (10) comprises a post (11), a rotary block (28) mounted on said post (11) for rotation about its axis perpendicular to that of said post (11), a plurality of radial arms (13) radially extending from said rotary block (28) at equal angular intervals, and swingable yarn package support pegs (14) pivotally joined to the extremities of said radial arms (13), respectively. An apparatus according to claim 11, characterized in that said rotary block (28) is combined with a gear wheel (18c) which can be indexed by a positioning pin (18e), said gear wheel (18c) being driven for rotation via a gear wheel (18b) by a motor (18a), wherein said yarn package support pegs (14) are combined with pinions (17b), respectively, which engage with a rack (17a). An apparatus according to one of the claims 1 to 7, characterized in that said yarn package stand device (10) comprises a post (11), a frame (19a) of a shape resembling the letter U, fixed to the upper end of said post (11) and having a pair of base members, a plurality of base plates (19b) provided on said base members, and a plurality of yarn package support units (20) for supporting yarn packages (Y), detachably mounted on said base plates (19b), respectively. An apparatus according to claim 13, characterized in that each of said yarn package support units (20) comprises a slide base (20a) capable of slidably engaging said base plate (19b), a plurality of brackets (22a) obliquely extending from the front surface of said slide base (20a), and yarn package support pegs (14) respectively attached to the respective extremities of said plurality of brackets (22a) so that the axes thereof converge substantially on a point (A) on the axis of the weft yarn inlet of said automatic weft yarn threading device (L₁). An apparatus according to claim 14, characterized in that said slide base (20a) of each of said yarn package support units (20) is provided with a dovetail (20c) at the back surface thereof, wherein a dovetail groove (19c) fitting said dovetail (20c) of said slide base (20a) is formed in each base plate (19b) provided on said base member of said frame (19a). An apparatus according to one of the claims 13 to 15, characterized in that said yarn package support units (20) are each provided with knobs (20b) to be gripped by said bobbin holding unit (54) of said yarn package transporting device (50). A yarn package changing method for replacing an empty bobbin (Y₀) by a new yarn package (Y) on a yarn package stand device (10) combined with a loom, comprising the steps of changing the position of a yarn package support peg (14) supporting said empty bobbin (Y₀), from a feeding position to a yarn package changing position, automatically removing said empty bobbin (Y₀) from said yarn package support peg (14) set in said yarn package changing position, transporting said new yarn package (Y) to a predetermined position with the leading end (Y₁) thereof being gripped, and holding said leading end (Y₁) at a position for transferring said leading end (Y₁) to an automatic weft yarn threading device (L₁) combined with said loom, and putting said new yarn package (Y) on said yarn package support peg (14) set in said yarn package changing position, and setting said yarn package support peg (14) supporting said new yarn package (Y) in said feeding position for feeding yarn from said new yarn package (Y). A method according to claim 17, characterized in that a plurality of yarn packages (Y) is supported in said feeding position and/or said yarn package changing position, wherein said yarn packages (Y) are supported in said yarn package changing position at a common position.

Inventors: NAGAI MASAHIRO, TAKEHANA TATSUO, TAMATANI YASUYUKI, NAGAI, MASAHIRO, TAKEHANA, TATSUO, TAMATANI, YASUYUKI
Applicants: TSUDAKOMA IND CO LTD, TSUDAKOMA KOGYO KABUSHIKI KAISHA
Application year: 1989
Main classification: D03D47
IPC codes: D03D47, B65H67