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(11) | EP 0 186 511 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Yarn storage and delivery apparatus |
| (57) A yarn wrapping member (16) and a yarn winding drum (7) are rotated in opposite directions.
Therefore, a yarn (21) fed to the yard wrapping member (16) is wrapped around the
yarn winding drum at a speed which corresponds to the sum of the rotative speeds of
the yarn wrapping member (16) and yarn winding drum (7). The yarn (21) unwound from
the yarn winding drum (7) is passed through the hollow portion of a main shaft (2)
for delivery to the outside. |
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] This invention relates to a yarn storage and delivery apparatus and particularly to a yarn storage and delivery apparatus used to feed a yarn under constant tension, for example.
Description of the Prior Art
[0002] As is known, weaving machines use a yarn storage and delivery apparatus for feeding a weft yarn under constant tension. Such yarn storage and delivery apparatus is used not only for feeding a weft yarn to a weaving machine but also in winders.
[0003] There are two types of known yarn storage and delivery apparatuses, the yarn winding drum rotation type or the so-called Savi type and the yarn winding drum stationary type or the so-called Sulzer type. A yarn storage and delivery apparatus of the Savi Type keeps the yarn wrapping member stationary while rotatively driving the yarn winding drum to wrap a predetermined amount of yarn therearound for storage. When the weaving machine starts operating, the yarn on the yarn winding drum is unwound therefrom under constant tension to be fed to the weaving machine. Concurrently therewith, the yarn winding drum is rotated to make up for the amount of unwound yarn. That is, while the yarn on the yarn winding drum is being withdrawn, additional yarn is wrapped therearound for supplement. On the other hand, a yarn storage and delivery apparatus of the Sulzer type keeps the yarn winding drum stationary while rotating the yarn wrapping member to wrap a predetermined amount of yarn around the yarn winding drum. As soon as the yarn comes to be unwound, the yarn wrapping member is started to make up for the yarn consumption.
[0005] In the Savi type yarn storage and delivery apparatus, since the yarn winding drum is kept rotating all the time, the yarn is caused to balloon even during intermittent delivery of yarn and hence there is little possibility of snarls being formed. Accordingly, the Savi type yarn storage and delivery apparatus is suitable for hard twist yarn. However, if the yarn speed exceeds 800 m/min, the use of a tension ring fitted on the yarn winding drum results in the tension ring finger spreading to decrease the tension until the latter is zero. For this reason, the Savi type has been limited in practical yarn speed to no more than 900 m/min.
[0006] On the other hand, in the Sulzer type yarn storage and delivery apparatus, since the yarn winding drum is kept stationary, the yarn hangs down at rest during intermittent delivery of yarn, tending to produce snarls; thus, this type is not suitable for use with hard twist yarn. The Sulzer type has a feature that there is no variation in tension taking place even when the yarn speed is above 800 m/min, since the tension ring is kept at rest. However, if the yarn speed exceeds 1200 m/min, the yarn wrapping rate becomes so high as to cause yarn breakage and is dangerous: Thus, the Savi type is suitable for use at low yarn speeds of not more than 800 m/min, while the Sulzer type is suitable for use at high yarn speeds of not less than 80 m/min. Both types, however, have the disadvantage of not being applicable to high speed yarn delivery in which the yarn speed exceeds 1200 m/min.
[0007] Accordingly the present applicant proposed, in Japanese Patent Application No. 172914/1982 (Japanese Patent Application Laid-Open No. 64473/1984), a yarn storage and delivery apparatus which eliminates the disadvantage of both types and which is capable of high speed yarn delivery. In brief, the apparatus according to this prior application includes a yarn wrapping member and a yarn winding drum which are rotatably supported, said yarn winding drum being adapted to be rotated in the direction opposite to the direction of rotation of said yarn wrapping member, so that if the rotative speeds of the yarn wrapping member and yarn winding drum selected are the maximum stable speeds, since the speed at which the yarn is wrapped around the yarn winding drum is the sum of the two speeds, 800 m/min + 1200 m/min = 2000 m/min can be attained; thus, the yarn winding speed can be greatly increased.
[0008] As described above, the yarn storage and delivery apparatus proposed by the applicant is an epoch-making apparatus capable of high speed yarn delivery making use of the advantages of the Savi and Sulzer types while compensating for their disadvantages; however, it leaves some room for improvement, as described below.
[0009] The yarn storage and delivery apparatus proposed by the present applicant is so arranged that the yarn wrapping member extends through a main shaft driven by a motor and is rotated, while the yarn winding drum is rotatably supported at the front end of said main shaft, the rotation of said main shaft being reversed in direction by a reverse rotation transmission mechanism and then transmitted to the yarn winding drum, whereby the yarn winding drum is rotated in the direction opposite to that of the yarn wrapping member. Therefore, said reverse rotation transmission mechanism has to be installed inside the yarn winding drum, thus complicating the construction and adding to weight, causing a problem of run-out taking place during operation. Further, the reverse rotation transmission mechanism, which has to be stationary with respect to the rotation of the main shaft, cannot be mechanically fixed to any fixed part because of t interference from the rotation of the yarn wrapping member; thus, stopping the rotation of the motor for stopping the rotation of the yarn winding drum often results in undesirable rotation of the reverse rotation transmission mechanism owing to inertial force due to the rotation of the yarn winding drum. Thus, an attempt has been made to magnetically fix the reverse rotation transmission mechanism by installing fixing magnets on the reverse rotation transmission mechanism and a fixed part opposed thereto. Such arrangement, however, offers problems of further complicating the construction and adding to weight.
SUMMARY OF THE INVENTION
[0010] Accordingly, a main object of this invention is to provide a yarn storage and delivery apparatus which is capable of solving all the problems of the prior application while making use of its advantages as such.
[0011] A yarn storage and delivery apparatus according to this invention comprises a yarn wrapping member, a yarn winding drum, a main shaft, and rotative drive means. The yarn wrapping member is rotatably supported by the main shaft, while the yarn winding drum is integrally supported by the main shaft. Further, the main shaft is internally formed with a hollow portion for allowing the yarn unwound from the yarn winding drum to pass therethrough. The rotative drive means rotates the yarn wrapping member and yarn winding drum in opposite directions to enable the yarn to be wound around the yarn winding drum at a speed corresponding to the sum of the rotative speeds of both members.
[0012] In this invention, a yarn is fed from one side and temporarily stored and then delivered to the other side. That is, the yarn fed to the yarn wrapping member from one side is wrapped around the outer peripheral surface from the other side by the yarn wrapping member and yarn winding drum rotating in opposite directions. The yarn wound on the yarn winding drum is unwound to one side and passes through the hollow portion of the main shaft for delivery to the other side.
[0013] According to this invention, since yarn is wound and stored on the yarn winding drum by rotating the yarn wrapping member and yarn winding drum in opposite directions, the yarn speed can be increased to a great extent as compared with that obtainable by a conventional Savi type or Sulzer type yarn storage and delivery apparatus, and the yarn can be delivered reliably at high speed without involving a no-tension state or yarn breakage, no matter how high the yarn speed may be.
[0014] Further, according to this invention, since there is no need to provide a reverse rotation transmission mechanism inside the yarn winding drum as in the prior art, simplification of construction and weight reduction can be attained.
[0015] These objects and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016]
Fig. 1 is a view showing the construction of a yarn storage and delivery apparatus according to an embodiment of the invention.
Fig. 2 is a view showing the construction of a yarn storage and delivery apparatus according to another embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] Fig. 1 is a view, partly in section, showing the construction of a yarn storage and delivery apparatus according to an embodiment of this invention. In this figure, a housing 1, which is a fixed part, includes a housing body la and a cover lb. The housing 1 has a main shaft 2 installed in the middle thereof. The main shaft 2 is journaled by bearings 3a - 3c fixed on the housing 1 and is rotatable relative to the housing 1. Further, the main shaft 2 is internally hollowed, and a cylindrical yarn delivery pipe 4 extends through the hollow portion. The main shaft 2 and the yarn delivery pipe 4 project at one of their respective ends 5 beyond the cover la. Further, adjacent the other ends 6 of the main shaft 2 and the yarn delivery pipe 4, a yarn winding drum 7 is fixed on the main shaft. The cover la is internally provided with a first motor 8 for rotating the main shaft 2. The first motor 8 is a DC motor which is called a print motor or flat motor. This motor 8 includes an armature 8a in the form of a copper disk and a yoke 8b. The armature 8a is fixed on the main shaft 2. The yoke 8b is fixed to the inner wall of the housing 1 and has a bearing 9 fixed thereto, which bearing 9 supports the main shaft 2. Further, the surface of the yoke 8b which is opposed to the armature 8a has field poles (for example, permanent magnets) 8c installed thereon at regular angular intervals (for example, of 90°). There are brushes 8d abutting against the lateral surface of the armature 8a.
[0018] Between the bearing 3a and the yarn winding drum 7, a rotary cylindrical member 10 is installed on the outher peripheral surface of the main shaft 2. Fixed on the inner peripheral surface of the rotary drive member 10 are bearings lla and 11b mounted on the main shaft 2. Therefore, the rotary drive member 10 is rotatable relative to the main shaft 2. A timing belt 12 is entrained around the outer peripheral surface of the rotary drive member 10. This timing belt 12 is also entrained around a pulley 14 fixed on the rotary shaft 13a of a second motor 13 (fixed to the lower portion of the housing 1), so that the rotary drive member 10 is rotated by the second motor 13. In addition, the direction of rotation of the rotary drive member 10 is opposite to that of the main shaft 2. Further, the other portion of the outer peripheral surface of the rotary drive member 10 has a yarn wrapping member 15 fixed thereon. Therefore, the yarn wrapping member 15 is rotated integrally with the rotary drive member 10. The yarn wrapping member 15 extends in a direction orthogonal to the main shaft 2, and its front end portion is bent substantially at right angle to extend parallel to the main shaft 2. That is, the front end portion of the yarn wrapping member 15 is opposed to the outer peripheral surface of the yarn wrapping drum 7. The bent front end portion of the yarn wrapping member 15 is formed with a throughgoing hole through which a yarn is passed to the outer peripheral surface of the yarn winding drum 7. In addition, a ceramic guide 16 is fitted in said throughgoing hole to present wear of the yarn wrapping member 15. Further, on the outer peripheral surface of the rotative drive member 10, a balancing member 17 is disposed diametrically opposite to the yarn wrapping member 15. The balancing member 17 is substantially as heavy as the yarn wrapping member 15, thus serving to prevent run-out due to deviation of the center of gravity.
[0019] An annular tension finger 18 is provided around the outer periphery of the yarn winding drum 7. The tension finger 18 serves to impart a suitable tension to the yarn unwound from the yarn winding drum 7. Sensors Sl and S2 are transversely spaced a predetermined distance apart so that they are opposed to the outer peripheral surface of the yarn winding drum 7. The sensor Sl is a photoelectric sensor for optically detecting the amount of the yarn wrapped around the yarn winding drum 7, i.e., the amount of stored yarn, when the amount decreases to a lower predetermined value. The sensor S2 is a photoelectric sensor for detecting the amount of the yarn wrapped around the yarn winding drum 7 when the amount exceeds an upper predetermined value.
[0020] A plate spring friction tenser 20 is provided on amount 19 fixed to the housing 1. This plate spring friction tenser 20 serves to impart a constant tension to the yarn fed to the yarn wrapping member 15.
[0021] In the arrangement described above, a yarn 21 fed from an unillustrated yarn supply source to the yarn storage and delivery apparatus is given a constant tension by the plate spring friction tenser 20 and then guided through the throughgoing hole of the front end portion of the yarn wrapping member 15 onto the inclined portion 7a of the outer peripheral surface of the yarn winding drum 7. Therefore, the yarn 21 is wrapped around the outer peripheral surface of the yarn winding drum 7 in accordance with the rotation of the yarn wrapping member 7. In addition, since the yarn 21 is first wrapped around the inclined portion 7a of the outer peripheral surface of the yarn winding drum 7, the convolutions of yarn 21 successively slide down this inclined portion 7a to push out the preceding stored convolutions of yarn forwardly (in the figure, to the left). Thus, the yarn 21 is regularly wound in a single layer without overlapping or crossing itself. In this case, the yarn winding drum 7 is rotated by the first motor 8 in the direction opposite to the direction of rotation of the yarn wrapping member 15. Thus, the speed at which the yarn 21 is wrapped around the outer peripheral surface of the yarn winding drum 7 is the sum of the rotative speeds of the yarn winding drum 8 and yarn wrapping member 15. For example, suppose that the speed at which the yarn is would by the rotation of the yarn winding drum 7 is 800 m/min and that the speed at which it is wound by the rotation of the yarn wrapping member 15 is 1,200 m/min, then the wrapping speed of the yarn 21 is 2,000 m/min, a value which is far greater than the one obtainable by the conventional Savi type or Sulzer type yarn storage and delivery apparatus. Moreover, since the rotative speeds of the yarn winding drum 7 and yarn wrapping member 15 are selected to be lower than the speeds at which the drawbacks of the Savi and Sulzer types manifest themselves, it is possible to utilize only the advantages of the Savi and Sulzer types. After having had a suitable tension imparted thereto by the tension finger 18, the yarn 21 wound around the yarn winding drum 7 is unwound from the yarn winding drum 7 and guided to the other end 6 of the yarn delivery pipe 4. The yarn 21 is passed through the yarn delivery pipe 4 and guided out of one end 5 of the yarn delivery pipe 4. The yarn 21 thus guided out is fed, e.g., as a weft yarn, to a weaving machine.
[0022] The operation of the sensor Sl and S2 will now be described. If the amount of yarn wound for storage on the winding drum 7 is small, there is no output from the sensor S2. Thus, drive currents are fed to the first and second motors 8 and 13 on the basis of the absence of an output from the sensor S2, so that the yarn winding drum 7 and yarn wrapping member 15 are rotated. Therefore, the yarn 21 is wound around the outer peripheral surface of the yarn winding drum 7 at a wrapping speed which corresponds to the sum of the rotative speeds of the yarn winding drum 7 and yarn wrapping member 15. When the sensor S2 detects the yarn 21 wound on the yarn winding drum 7, its output stops the supply of currents to the first and second motors 8 and 13, thereby stopping their rotation.
[0023] The yarn 21 wound on the yarn winding drum 15 is fed through the tension finger 18 and yarn feed pipe 4 to a weaving machine or the like, as described above. Thus, when the yarn 21 is pulled by the weaving machine, the amount of yarn 21 wound for storage on the yarn winding drum 7 gradually decreases until the portion of the yarn 21 opposed to the sensor S2 is delivered. Then, the sensor S2 detects the absence of the yarn 21, so that drive currents are fed again to the first and second motors 8 and 13. Thus, the first and second motors 8 and 13 are rotated to rotate the main shaft 2 and yarn wrapping member 15 in opposite directions. This operation is continued until an output from the sensor S2 is obtained.
[0024] Thereafter, in the same way, the sensor S2 detects the yarn 21, whereupon the first and second motors 8 and 13 are stopped, and when the sensors Sl ceases to detect the yarn 21, the first and second motors 8 and 13 are driven. In this way, a fixed amount of yarn is intermittently wound on the yarn winding drum 7 for a vary short time or the wound and stored yarn is delivered.
[0025] If the yarn 21 is suddenly pulled for some reason or other, it often occurs that the yarn 21 wound on the yarn winding drum 7 disappears. To prevent this situation, it is so arranged that when the sensor Sl detects the absence of the yarn 21, the first and second motors 8 and 13 are driven at increased rotative speeds.
[0027] First, there is an advantage that delivery of yarn at much higher speeds than in conventional Savi type and Sulzer type yarn storage and delivery apparatuses is possible, without causing disadvantages involved in high speed operation, as described above.
[0028] Next, in the aforesaid embodiment, since there is no need for a reverse rotation transmission mechanism as needed by a yarn storage and delivery apparatus according to the present applicant's prior application, the construction is extremely simplified and weight reduction can be attained. Further, there is no need to provide fixing magnets needed by a reverse rotation transmission mechanism, so that further simplification of construction and further reduction in weight can be attained. Such advantage is produced because of the fact that in the aforesaid embodiment the yarn winding drum is fixed to the main shaft 2 for rotation while the yarn unwound from the yarn winding drum is passed through the interior of the main shaft 2 for delivery to the outside, with the result that the rotary cylindrical member 10 can be supported on the outer peripheral surface of the main shaft 2 and the outer peripheral surface of the rotary cylindrical member 10 can be utilized to impart rotative force to the yarn wrapping member 15. In contrast, in the yarn storage and delivery apparatus according to the present applicant's prior application, since the member (the yarn wrapping member) through the interior of which yarn is passed is fixed to the main shaft for rotation, the member (the yarn winding drum) around the outer peripheral surface of which yarn is passed cannot have rotation transmitted thereto from the outer periphery because of interference of yarn, thus requiring a reverse rotation transmission mechanism.
[0029] In addition, in the aforesaid embodiment, the first motor 8 directly connected to the main shaft 2 is used to rotate the main shaft 2, but said first motor, like the second motor 13, may be one installed outside to have its rotation transmitted to the main shaft 2 by belting or gearing.
[0030] While two motors have been used in the aforesaid embodiment, a single motor may be sued to rotate the yarn winding drum 7 and yarn wrapping member 15. The construction of such embodiment is shown in Fig. 2. In the figure, this embodiment is the same as the one shown in Fig. 1 except the following points, and like parts are denoted by like reference numerals to omit a description thereof. In this embodiment, the first motor 8 in Fig. 1 is omitted and a second motor (hereinafter referred to simply as the motor) 13 is used to rotate also the yarn winding drum 7. That is, the motor 13 has its rotary shaft 13a projecting in opposite directions, so that on the rotary shaft 13a projecting to one side a pulley 14 is fixed and rotates the rotary cylindrical member 10 and hence the yarn wrapping member 15 by belting. On the rotary shaft 13a projecting to the other side, a pulley 22 is fixed. The pulley 22 has a timing belt 23 entrained therearound. On the other hand, in the interior of the housing 1, a rotary shaft 25 is journaled in bearings 24a and 24b fixed on the cover lb. A pulley 26 is fixed on the rotary shaft 25 and has said timing belt 23 entrained therearound. Further the rotary shaft 25 has a gear 27 fixed thereon. The gear 27 meshes with a gear 28 fixed on the main shaft 2.
[0031] In the aforesaid arrangement, when the motor 13 is rotated, the rotation of the rotary shaft 13a is transmitted to the rotary shaft 25 by the timing belt 23. The rotation of this rotary shaft 25 is reversed by the gears 27 and 28 and transmitted to the main shaft 2. Therefore, the main shaft 2 is rotated in the direction opposite to the direction of rotation of the rotary cylindrical member 10. The rotative speed of the yarn winding drum 7 can be set to any desired value by suitably selecting the gear ratio of gears 27 and 28.
[0032] In addition, in the embodiment in Figs. 1 and 2, the rotary cylindrical member 10 is rotated by belting, but gears or a combination of gears and belts may be used for transmission of rotation.
[0033] Further, in the embodiment in Fig. 1, the first motor 8 is directly connected to the main shaft 2, but belting or gearing may be used for transmission of rotation.
[0034] Further, in the embodiments shown in Figs. 1 and 2, a yarn wrapping member in the form of a bar is used, but this yarn wrapping member is not limited to a bar form but may be a disk or cylindrical (mushroom) form. In that case, the balancing member is unnecessary.
[0035] Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.
1. A yarn storage and delivery apparatus for temporarily storing a yarn (21) fed from
one side and delivering it to the other side, comprising:
a yarn wrapping member (15) fed with a yarn from said one side,
a yarn winding drum (7) disposed on said one side relative to said yarn wrapping member and having a yarn wound therearound from said other side by the rotation of said yarn wrapping member and its own rotation and unwound therefrom to said one side,
a main shaft (2) rotatably supporting said yarn wrapping member and integrally supporting said yarn winding drum and internally formed with a hollow portion through which the yarn unwound from said yarn winding drum is led to said other side, and
rotative drive means (8, 13) for imparting rotative forces of opposite directions to said yarn wrapping member and said yarn winding drum.
2. A yarn storage and delivery apparatus as set forth in Claim 1, wherein said rotative
drive means comprises:
a first motor (8) directly connected to said main shaft,
a second motor (13), and
a rotative force transmitting mechanism (10, 12, 14) for transmitting the rotative force of said second motor to said yarn wrapping member.
3. A yarn storage and delivery apparatus as set forth in Claim 1, wherein said rotative
drive means comprises:
a single motor (13),
a first rotative force transmitting mechanism (22 - 28) for transmitting the rotative force of said motor to the outer peripheral surface of said main shaft, and
a second rotative force (10, 12, 14 ) transmitting mechanism for transmitting the rotative force of said motor to said yarn wrapping member.
4. A method of storing and delivering yarn, in which the yarn is wound on a drum (7)
by a yarn wrapping member (15) while the drum (7) and member (15) are rotated in opposite
directions about substantially coincident axes, and in which the yarn is delivered
by unwinding the yarn from the drum, characterised in that the yarn is delivered from
the drum along a path disposed substantially on said axes of rotation.