Shed-forming mechanism applied to a circular loom

Abstract: In a circular loom provided with a main drive shaft, a plurality of healds (46) are arranged in a ring-shaped alignment coaxially around the main drive shaft, an annular reed member (25) is stationarily located inside the ring-shaped alignment of the healds (46) and coaxially therearound, wherein shuttles are able to move along an annular passage defined by the annular reed member (25), a weft taken out from each of the shuttles is inserted to successive sheds created by a shed-forming mechanism (45) so that the inserted weft is interwoven with the warps to form a tubular fabric having a predetermined weave structure, by applying a particular shed forming mechanism (45) based upon a principle such that the shedding operations of a unit group of warps to creat, each one repeat weave structure is controlled to satisfy the crossing condition between said warps and said inserted weft for creating said one repeat weave structure.

Description: The present invention relates to a shed-forming mechanism and to a circular loom utilising the novel shed-forming mechanism. Such a circular loom can be used for producing a tubular fabric having a satin weave structure. US4,424,836 discloses a shed-forming arrangement for a circular loom provided with: a plurality of healds disposed in a circular array, an annular reed member located within said array of healds, means for supplying warps (W) to said healds, said supplying means being disposed outside said array, each of said healds being provided with an eye for threading a warp supplied from said supply means, and shuttles arranged to move along an annular passage defined by said reed member, said shed-forming arrangement comprising a plurality of shed-forming mechanisms arranged to be disposed between said supply means and said reed member and coupled to respective groups of said healds, whereby in use a weft taken out from each of said shuttles is inserted into successive sheds created by motion of said healds out of the plane of said annular passage before the arrival of said shuttle, and said weft is interwoven with warps to form a tubular fabric having a predetermined weave structure. In the above conventional circular loom, shuttles are moved along a circular running passage, a weft taken out from each shuttle is inserted to successive sheds created before the arrival of the shuttle, and the weft is interwoven with warps to form a tubular fabric. The conventional circular loom of this type has been designed only to produce a tubular fabric having a plain weave structure, and therefore, the shed-forming mechanism is characterized by a construction for controlling the shed-forming motion of warps in such a way that each two adjacent warps move in opposite directions respectively, in each shed formation to create the plain weave structure. It is known that a tubular fabric has a high extensibility if used in the bias-cut condition, and the market for tubular fabrics in industrial use has recently expanded. Further, research by the present inventors confirmed that, if a satin weave structure is applied to the tubular fabric, this extensibility is greatly improved. Nevertheless, the conventional circular loom cannot be used to produce a tubular fabric having a satin weave structure, because the shed-forming mechanism of the conventional circular loom is designed to produce a tubular fabric having a plain weave structure, as mentioned above. Therefore, a primary object of the present invention is to provide a circular loom by which the motion of the warps is controlled in such a manner that the shed-forming motion of the warps follows the one repeat of the basic structure of the desired satin weave structure. The present invention provides a shed-forming arrangement as disclosed in US4,424,836, characterised in that the shed-forming arrangement is arranged to move the healds of each group selectively to form said successive sheds in a repeating pattern in which successive wefts (F) cross different warps (W), whereby a repeating weave structure is formed, the number of warps in each group being equal to the number of warps in one repeat of the weave structure. The invention also provides circular looms utilising such shed-forming arrangement as defined in the dependent claims. Preferred embodiments of the invention described below by way of example only with reference to the accompanying drawings wherein: Fig. 1 is a schematic perspective view of a conventional circular loom to which the present invention can be applied; Fig. 2 is a schematic view of the main part of the circular loom shown in Fig. 1; Fig. 3 is a perspective schematic view showing a shed-forming mechanism of the circular loom shown in Fig. 1, for producing a tubular fabric having a plain weave structure; Fig. 4 is a schematic elevation view of a tubular fabric and showing a bias-cut applied thereto; Fig. 5 shows a one repeat weave structure of eight healds satin weave structure; Fig. 6 is a time chart indicating the relative shed-forming motions of eight warps when creating the one repeat weave structure of eight healds satin weave structure; Fig. 7 is a perspective schematic view showing a first embodiment of the shed-forming mechanism applied to the circular loom in Fig. 1, and replacing the shed-forming mechanism shown in Fig. 3, according to the present invention; Fig. 8 is an explanatory view showing the basic technical concept of controlling the shed-forming motion of the warps of a unit group based upon the number of warps needed to construct the one repeat weave structure of eight healds satin weave structure; Fig. 9 is a schematic side view of the second embodiment of the shed-forming mechanism applied to the circular loom, similar to the first embodiment of the present invention; and, Fig. 10 is a view of the third embodiment of the shed-forming mechanism applied to the circular loom, similar to the first embodiment of the present invention. Before explaining the preferred embodiments of the present invention, to facilitate an easy understanding of the present invention, the mechanism and the function of the conventional circular loom are briefly explained with reference to Figs. 1, 2, and 3. In the circular loom 11 shown in Fig. 1, a main part 14 including a shed-forming means and filling means is mounted within a frame 19; the shed-forming means and filling means being driven by an electric motor 15 mounted below the main part 14, through a first power transmission mechanism (not shown). A tubular fabric take-out means 18 mounted on the frame 19 above the main part 14 is driven by a second power transmission mechanism (not shown) connected to the take-out means 18. This second power transmission mechanism is driven by the first power transmission mechanism through a drive transmission lever 21, and thus the take-out means 18 is driven synchronously with the main part 14. A number of warps w for weaving a required tubular fabric 12 are fed to a pair of creels 16 arranged symmetrically to each other on both sides of the main part 14, with respect to the main part 14 (only one creel arranged on the right side is illustrated Fig. 1), from a plurality of packages 16a, mounted rotatably for feeding the warps w, and the warps w are fed to the main part 14 through a warp feed mechanism 17. The tubular fabric 12 formed by a weaving operation in the main part 14 of the circular loom 11 is taken out upwardly by the take-out means 18 and guided to a winding means (not shown) in the direction indicated by an arrow. As shown in Figs. 1 and 2, the main part 14 of the circular loom 11 is provided with a vertical shaft 24 rotatably supported on bearings fixed to a central opening of a supporting frame 26 secured to the frame 19, a cylindrical cam mechanism 29 fixed to the shaft 24 at a position above the supporting frame 26, a shed-forming mechanism 30 which is operated by the cylindrical cam mechanism 29, four shuttle propelling mechanisms 23 fixed to a supporting mechanism 22 fixed to the shaft 24 at a position above the cylindrical cam mechanism 29, an annular reed member 25 comprising a pair of ring-shaped holding members 25a, 25b and a plurality of reed elements 31 rigidly supported by the ring-shaped holding members 25a, 25b in vertical condition with an identical spacing between each two adjacent reed elements 31, a horizontal disc guide member 27 supported rotatably on the top of shaft 24 to guide another wheel 13c of a shuttle 13, and an annular guide 28 held by supporting arms 32 in a stationary condition, with a small clearance between the guide 28 and the top end of the annular edge of the horizontal disc guide member 27. As shown in Figs. 1, 2, and 3, warps w are supplied from the creels 16 at both side of the circular loom 11, and are threaded into the respective spaces between each two adjacent reed elements 31 of an annular reed member 25 rigidly supported by the ring-shaped holding members 25a and 25b, after passing through the respective eyes of corresponding healds 38 of the shed-forming mechanism 30. The shuttles 13 are propelled by the shuttle propelling mechanism 23 and inserted to the shed created by the shed-forming mechanism 30, and then a weft yarn f from the shuttle 13 is inserted to the shed by the wheel 13c, whereby a stable weave structure is created to form a tubular fabric 12. The tubular fabric 12 is taken out upwardly via a small annular shaped clearance formed between the horizontal guide member 27 and the outside guide member 28, and the tubular fabric 12 is then wound on a roll of a take-up mechanism (not shown). In the above-mentioned circular loom, as shown in Fig. 3, the shed-forming means consists of a plurality of vertical guide rods 35 fixed to the peripheral flange portion of the supporting frame 26, a cam follower holding member 36 slidably mounted on the guide rods 35, an annular cam 29a protruded beyond the periphery of the cylindrical cam mechanism 29, a pair of cam followers 37a, 37b rotatably mounted on the holding member 36 and in rolling contact with the cam 29a from the upper and lower directions, heald frame guides 40 mounted on the upper annular guide member 25a to guide a pair of healed frames, i.e., to guide an inner heald frame 41a and an outer heald frame 41b, belts 42a, 42b connecting the two heald frames 41a, 41b so that the heald frames 41a, 41b are moved alternately in the upper and lower directions to form a shed, and belt guides 34 (only one shown) mounted on the peripheral flange portion of the frame 26 to guide and support the belts 42a, 42b. The holding member 36 to which the cam followers 37a, 37b are attached is connected to the belt 42b by a pin member 33, and thus a vertical movement is given to the heald frame 41a by the vertical movement of the holding member 36. This vertical movement is transmitted to the other heald frame 41b through the belts 42a, 42b, and therefore, the outer heald frame 41b moves up and down in a reverse direction with respect to the movement of the inner heald frame 41a. The heald frames 41a, 41b are each provided with an equal number of healds 38, and a number of vertical rods 39 corresponding to the number of healds 38 are firmly positioned to form a vertically oriented grid between the upper and lower opposing guide members 25a, 25b constituting the annular reed member 25. The shape of the cam surface of the protruded annular cam 29a is designed with respect to the heald frames 41a, 41b in such a manner that a full-open shed is formed. By alternately passing the adjacent warps w through the mails of the healds 38, a shed constituting a plain weave fabric can be formed by rotating the cylindrical cam mechanism 29. Since a plurality of pairs of the heald frames 41a, 41b are annularly arranged adjacent to each other along the periphery of the cylindrical cam mechanism 29, the pairs of heald frames 41a, 41b successively form sheds having an identical shape, in accordance with the rotation of the horizontal cylindrical cam mechanism 29, and accordingly, a plain weave tubular fabric 12 can be produced by propelling a plurality of shuttles 13. As mentioned above, in the conventional circular loom used to produce a tubular fabric having a plain weave structure, since the shedding motion applied to the warps w is carried out in a simple way such that two adjacent warps w always take opposite positions upon each formation of an open shed, it is sufficient to use a plurality of combinations of the two heald frames 41a, 41b which are displaced in directions opposite to each other. As explained above, a tubular fabric having a satin weave structure is very valuable for industrial use if the fabric is cut in a bias-cut as shown in Fig. 4, wherein the fabric is cut along a line L inclined by 45 degrees to the longitudinal direction thereof, but to produce such a tubular fabric provided with a satin weave structure, it is obvious that the shed-forming mechanism utilized in the conventional circular loom cannot be adopted. After intensive research, the following basic technical concept was obtained, whereby the object of the present invention can be attained. During this research, consideration was given to meeting the requirements of practical use, i.e., an easy threading of the warps into the respective healds, an easy weaving operation, and no expansion of the space needed for installation of the circular loom, etc. In view of the above considerations, the following conditions were found to be essential to the creation of the shed-forming mechanism of the present invention to be applied to a circular loom having the same mechanism as the conventional circular loom. Namely, all of the warps w are considered as a plurality of successive groups of warps w, wherein each group of warps w are successively threaded through the respective eyes of corresponding healds successively arranged coaxially to the annular reed member 25, and the number of warps w of each group coincides with the number of warps of a one repeat weave structure, i.e, one repeat satin weave structure. Further, as in the case of weaving a plain fabric by a conventional power loom, when producing a tubular fabric having a satin weave structure, it is essential that the shed-forming motions of the element warps w of each group corresponds to the arrangement of each crossing point between the element warps w and the element wefts f for forming "one repeat weave structure". The construction and function of the shed forming mechanism according to the present invention is hereinafter explained in detail with reference to the attached drawings. Figure 5 shows the relationship between the passage of a shuttle 13 and the position of the respective warps w, represented as w1, w2, w3, w4, w5, w6, w7, and w8, in the respective shed formations to create a one repeat weave structure of an eight healds satin weave structure, wherein each cross mark indicates a warp w which crosses a corresponding weft f in such a manner that the warp w takes a position below the weft f. This one repeat weave structure shows a lower shed system of the shed-forming motion. To facilitate an easy understanding of this shed-forming motion, the relative positions of the shuttle 13 to the warps w1, w2, w3, w4, w5, w6, w7, and w8 at each shed formation s1, s2, s3, s4, s5, s6, s7 and s8 are shown in Fig. 6. Namely, in the first shed formation s1, the first warp w1 is moved below the passage of the shuttle 13 while the other warps w2, w3, w4, w5, w6, w7 and w8 remain at their standby positions, respectively; in the second shed formation s2, only the sixth warp w6 is moved below the passage of the shuttle 13; in the third shed formation s3, only the third warp w3 is moved below the passage of the shuttle 13; in the fourth shed formation s4, only the eighth warp w8 is moved below the passage of the shuttle 13; in the fifth shed formation s5, only the fifth warp w5 is moved below the passage of the shuttle 13; in the sixth shed formation s6, only the second warp w2 is moved below the passage of shuttle 13; in the seventh shed formation s7, only the seventh warp w7 is moved below the passage of the shuttle 13; and in the eighth shed formation s8, only the fourth warp w4 is moved below the passage of the shuttle 13; in the shed formations s2, s3, s4, s5, s6, s7, and s8, the other warps remain in their standby positions, respectively. Referring to Figs. 7 and 8, the first embodiment of the shed-forming mechanism according to the present invention is explained in detail. As can be easily understood from the above explanation, the shed-forming mechanism is composed of a plurality of unit shed-forming mechanisms successively arranged in an alignment and coaxially to the annual reed member 25, to operate in combination with the cylindrical cam mechanism 29 in which the cam follower 29a protrudes beyond the periphery of the cylindrical cam mechanism 29. Each unit shed-forming mechanism comprises a group of healds 46 successively arranged in an alignment therein, a heald holding member consisting of an upper heald holder 45a and a lower heald holder 45b, which function to hold the healds 46 in an alternately upward and downward displaceable condition, and a means for selectively providing the above-mentioned upward and downward displacement of one of healds 46 each time a shed is formed. This means comprises, in combination with the cylindrical cam mechanism 29, a pair or vertical guide rods 35 a holding member 47 supported by the vertical guide rods 35 so as to be displaceable upwardly and downwardly, and a horizontal annular body 48 rigidly mounted on the vertical guide rods 35 of each unit shed forming mechanism the annular reed member 25 being rigidly mounted on the annular body 48 coaxially thereto. The holding member 47 is provided with a pair of cam followers 49a, 49b having an identical function to that of the cam followers 37a, 37b of the conventional circular loom, and accordingly, the holding member 47 can be displaced upward or downward along the vertical guide rods 35. A control cylinder 50 is rotatably mounted on a horizontal shaft (not shown) supported by the holding member 47 and a ratchet wheel mechanism 51 by which the control cylinder 50 is rotated by a predetermined angle α at each actuation thereof, and an actuation member 52, for actuating the ratchet wheel mechanism 51, is projected upward toward the annular body 48. A predetermined number of projecting members 53 are axially projected from the cylindrical surface of the control cylinder 50 at respective positions of which each projecting member 53 can be engaged with a corresponding hook 54 formed at the bottom end of each of the healds 46. Each heald 46 is connected to helical spring 55, so that each heald 46 is always in the standby position except when the hook portion 54 of the heald 46 is pulled down by the action of the projection 53 of the control cylinder 50. The annular cam 29a of the cylindrical cam mechanism displaces the holding member 47 between a lowermost position at which the projecting member 53 displaces the corresponding hook 54 of the heald 46 to the lowermost position thereof to create a bottom open shed, and an uppermost position at which the member 53 is completely separated from the engaged hook 54 after the heald 46 is returned to the standby position by the force of the spring 55. The actuation member is provided with a function such that, when the actuation member is pressed by the bottom surface of the annular body 48, the actuation member actuates the ratchet wheel mechanism 51 and causes it to be rotated by a predetermined angle α, as hereinafter explained in detail. The arrangement of the projecting members is defined by the principle based upon the one repeat weave structure mentioned with reference to Figs. 5, and 6. The following additional explanation with reference to Fig. 8 will facilitate an understanding of this principle. In Fig. 8, since the numbers of crossing points of the warp w and the weft f in "one repeat weave structure" of an eight heald satin weave structure are eight, respectively, if a circle 50a which represents one rotation in the clockwise direction of a point on the cylindrical surface of the control cylinder 50, is divided into eight portions s1, s2, s3, s4, s5, s6, s7 and s8, with an identical arcuate length between each two adjacent points these divided points s1, s2, s3, s4, s5, s6, s7 and s8, on the circle 50a represent the timing points for forming sheds to produce a tubular fabric having an eight heald satin weave structure. Therefore, if the control cylinder 50 is rotated clockwise in Figs. 7 and 8, each time the control cylinder 50 is rotated by the above-mentioned predetermined angle α (in this embodiment, α is 360/8 degrees = 45 degrees) one of the projecting members 53 is engaged with the hook 54 of the corresponding heald 46 if the control cylinder 50 is located at a position such that the above engagement can be made, and the projecting members 53 are arranged in a condition such that the circular tracks thereof are arranged on the cylindrical surface of the control cylinder 50 at an identical spacing therebetween along the axial direction thereof, which coincides with the spacing between two hooks 54 of two adjacent healds 46. To facilitate an understanding of the above explanation, in Fig. 8 the tracks of the projecting members are represented as w1, w2, w3, w4, w5, w6, w7, and w8, respectively and the angular positions of the projecting members 53, which are selected based upon the eight healds satin weave structure, are indicated by c1, c2, c3, c4, c5, c6, c7, and c8, respectively. Therefore, the projecting members 53 arranged on the cylindrical surface of the control cylinder 50 as mentioned above are engaged one by one with one of the hooks 54 of the corresponding healds 46, due to the above arrangement of the projecting members 53 which is selected in accordance with the required weave structure (in this embodiment, an eight healds satin weave structure). Referring to Fig. 7, the healds 46 simultaneously follow the action of the control cylinder 50 at each shed forming, and therefore, the above-mentioned control motion of the shed formation is applied to all of the unit shed forming mechanisms, whereby a tubular fabric having the desired weave structure can be produced. The above-mentioned shed-forming motion by the shed-forming mechanism is hereinafter explained in more detail with reference to Fig. 7. During the weaving operation by the circular loom provided with the above-mentioned shed-forming mechanism, the holding member 47 of each unit shed-forming mechanism is displaced upward and downward by the action of the cylindrical cam mechanism 29. In each shed-forming mechanism, after the holding member 47 is displaced to the uppermost position thereof, when the holding member 47 is to be displaced downward, one of projecting members 53 of the control cylinder 50 is positioned at a horizontal position such that this projecting member 53 can be engaged with a hook 54 of a corresponding heald 46 (this hook is hereinafter referred to as a particular hook 54, and the heald of this particular hook 54 is referred to as a particular heald 46), while the other projecting members 53 are arranged at respective angular positions of the control cylinder 50 at which they cannot come into contact with the respective hooks 54 of the corresponding healds 46. Accordingly, when the holding member 47 is displaced downward, the above-mentioned particular hook 54 of the particular heald 46 is also displaced downward by the downward displacement of the holding member 47, because the particular hook 54 is engaged with the projecting member 53, whereby the particular heald 46 only is displaced to the lowermost position, while the other healds 46 remain at their standby positions. Accordingly, a "bottom open shed" for creating a satin weave structure is formed, and when this "bottom open shed" is formed, the shuttle 13 is successively inserted to this shed so that a unit weave structure can be created after forming the successive sheds. Since the timing at which the shuttle 13 is inserted to the shed is very important, the propelling of the shuttle along the annular reed member 25 is carried out synchronously by the rotating motion of the cylindrical cam mechanism 29, as in the conventional circular loom. After the downward motion of the holding member 47, the holding member 47 is displaced upward by the action of the cylindrical cam mechanism 29, and the particular heald 46 is pulled upward by the force of the spring 55, while maintaining the engagement between the particular hook 54 and the corresponding projecting member 53, until the particular heald 46 arrives at the uppermost position thereof. The holding member 47 is further displaced upwards so that the engagement between the hook 54 and the projecting member 53 is released, and thereafter, the actuating member 52 is forced into contact with the bottom surface of the annular body 48 so that the actuating member 52 causes the ratchet wheel mechanism 51 to rotate, whereby the control cylinder 50 is rotated by the predetermined angle α (in this embodiment, 45 degrees). Due to this one unit rotation for α degrees of the control cylinder 50, the next projecting member 53, which is defined as mentioned above, comes to the working position to cause the next unit shed to weave the desired weave structure. The shed-forming motion of each unit shed-forming mechanism is thus continuously carried out by rotating the cylindrical cam mechanism 29. In the above embodiment, the case of producing a tubular fabric provided with an eight healds satin weave structure is explained, but if a tubular fabric having a five healds satin weave structure is required, the number of unit shed forming mechanisms, number of healds of each unit shed forming mechanism, and the number and arrangement of the projecting members 53 of the control cylinder 50 can be easily changed by applying the technical concept of the above-mentioned embodiment, and therefore, an explanation thereof is omitted. In the second embodiment of the present invention shown in Fig. 9, the shed-forming mechanism is characterized by a modified mechanism for selecting the particular heald 46 in the weaving operation. As shown in Fig. 9, each heald 46 of the unit shed-forming mechanism is provided with a slit 46a formed along the lengthwise direction and at the upper portion thereof. Further, a plurality of horizontal arms 57, in a number identical to the number of healds 46 of the unit shed-forming mechanism, are extended from the annular reed member 25 in such a manner that a small shaft 57a secured to each horizontal arm 57 is inserted into the slit 46a of the corresponding heald 46 such that the heald 46 can be displaced upward and downward while able to turn about the small shaft 57a. The holding member 47 is provided with a horizontal recess 58 having sharp edge portion forming a hook by which the hook portion 54 of each heald 46 can be caught. A plurality of plate cams 59 are rotatably disposed above the holding member 47 at respective positions closely facing the corresponding healds 46, and a plurality of urging elements 60 provided with a pushing element utilizing a spring force are arranged to always push the respective healds 46 away from the feeding side of the warps w, so that each heald 46 is always pushed against the corresponding plate cam 59. Each plate cam 59 is provided with a means for turning by the predetermined angle α, as explained in the description of the first embodiment of the present invention, each time the holding member 47 is reciprocally displaced upward and downward. A mechanism such as a rack and pinion, wherein the rack is actuated by the motion of the holding means, can be utilized for this invention. In this mechanism, an additional mechanism, provided with such function to rotate the plate cam 59 only at the time of either one of the above-mentioned upward and downward displacement of the holding member 47, involves. The mechanism for displacing the holding member 47 upward and downward is similar to that used in the first embodiment, and thus an explanation thereof is omitted. Each cam plate 59 is provided with a recessed portion at which the corresponding heald 46 is turned about the small shaft 57a, so that the hook portion 54 of the heald 46 can take a position at which it can be engaged with the hook portion formed by the recess 58. The relative arrangement of the recessed portions of the plate cams 59 of the unit shed-forming mechanism, with respect to the axial center thereof, is made on the same principle as that of the relative arrangement of the projecting members 53 of the control cylinder 50 of the first embodiment, and thus an explanation thereof is omitted. The shed-forming motion of the second embodiment is carried out as explained hereinafter. In the above-mentioned unit shed-forming mechanism shown in Fig. 9, the holding member 47 is once displaced downward and then reciprocally displaced upward when the actuation part of the annular cam 29a of the cylindrical cam mechanism 29 actuates the unit shed-forming mechanism to make a shed, which one unit of a plurality of sheds needed to construct a one repeat weave structure. If one of the cam plates 59 takes an angular position such that the recessed portion thereof faces the corresponding heald 46, this heald 46 is turned clockwise about the small shaft 57a (in Fig. 9), so that the hook portion 54 of the heald 46 can be engaged with one of the hook edge portions 61 of the recess 47, and accordingly, this heald 46 is displaced to the lowest position thereof by the downward displacement of the holding member 47, while the small shaft 57a slides in the slit of the heald 46, and thus the bottom open shed is formed. When the holding member 47 is displaced upward, the cam plate 59 is turned by the predetermined angle α (in this embodiment, α is 45 degrees), so that the recessed portion of the cam plate 59 is angularly displaced from the above-mentioned facing position, and accordingly, the heald 46, as one of the healds 46 of the unit shed-forming mechanism, is turned in the counter-clockwise direction (Fig. 9) by following the turning motion of the cam plate 59. Therefor, the hook portion 54 of the heald 46 is separated from the hook edge portion 61 of the recess 58 of the holding member 47, and then pulled upward by the force of the spring (not shown), as in the first embodiment, to the upper most position (standby position) thereof. The above-mentioned shed-forming motion is applied to all healds 46 of the unit shed-forming mechanism in the same way as in the first embodiment, so that a one repeat weave structure of the desired tubular fabric is formed. The third embodiment shown in fig. 10 of the shed-forming mechanism is a modification of the above-mentioned first and second embodiments of the present invention. In this third embodiment, many machine elements having functions similar to those of the above-mentioned embodiments are utilized, and these machine elements are represented by the identical reference numerals to those of the above embodiments, and therefore, an explanation thereof is omitted. As can be understood from the above-mentioned explanation of the first and second embodiments of the present invention, the space between two adjacent healds is relatively small, and thus in practice it is desirable to widen this space. Accordingly, in the third embodiment of the present invention, the space between two adjacent healds is enlarged to twice that of the above-mentioned first and second embodiments. Namely, in each unit shed-forming mechanism, the healds 46A, 46B are arranged in two alignments along respective horizontal circular arrangements, coaxially with each other as shown in Fig. 10. The arrangement of the healds 46A along the inside circular arrangement is hereinafter referred to as an inside arrangement, and the arrangement of the healds 46B along the outside circular arrangement is hereinafter referred to as an outside arrangement. Accordingly, a different mechanism for selectively creating the unit sheds when weaving a tubular fabric having a satin weave threads structure becomes necessary. Since the healds 46 of each unit shed-forming mechanism are arranged in two rows in the radial direction, the following technical concept is applied. Namely, one reciprocal upward and downward displacing motion of the holding member 47 is utilized to operate, separately and successively, a pair of healds 46A, 46B of the inside arrangement and the outside arrangement, so that, for example, when producing a tubular fabric having an eight healds satin weave structure, four plate cams 59 are utilized. Therefore, when utilizing the healds supporting mechanism as in the second embodiment, the cam plates 59 are arranged to rotate by a half revolution at each reciprocal upward and downward displacing motion of the holding member 47, to displace one of the healds 46A of the inside arrangement to the bottom position at an identical level, or to displace one of the healds 46B of the outside arrangement to the bottom position at an identical level. To create the above-mentioned motion of the healds 46A, 46B, an endless belt 62 having a width equal to a space covering the motions of the healds 46A and 46B is arranged in such a manner that the endless belt 62 is guided by five guide rollers 63a, 63b, 63c, 63d and 63e, rotatably motioned on brackets (not shown) secured to the machine frame of the circular loom, while the endless belt 62 is connected to the holding member 47 so that the endless belt 62 is reciprocally moved towards an arrow D1 or an arrow D2 in accordance with the reciprocal upward and downward motion of the holding member 47. The endless belt 62 is provided with two groups of hook members 66a, 66b arranged in such a manner that each one of the hook members 66a can displace the corresponding heald 46A of the inside arrangement to the bottom position thereof when the hook member 66a is engaged with the hook portion 54 of the heald 46A, and each one of the hook members 66b can displace the corresponding heald 46B to the bottom position thereof when the hook member 66b is engaged with the hook portion 54 of the heald 46B. The above-mentioned engagement of the hook portion 54 to either one of the healds 46A, 46B is controlled by the motion of the cam plates 59, which act on the corresponding healds 46A, 46B in a manner similar to that of the cam plate 59 in the second embodiment, except that each cam plate 59 acts alternately on the corresponding heald 46A and 46B at each 180 degrees rotation thereof, as shown in Fig. 10. As explained with reference to the first embodiment of the present invention, each time a shed is formed to create one repeat weave structure, the shuttle 13 is inserted into the shed in accordance with the weave structure. Therefore, the arrangement of the hook members 66a and 66b is based on the principle explained with reference to the first embodiment. In the third embodiment, however, since two groups of healds, i.e., the healds 46A of the inside arrangement and the heald 46B of the outside arrangement, are used, the group hook members 66a are arranged against the respective hook portions 54 of the corresponding healds 46A of the inside arrangement, and the group hook members 66B are arranged against the respective hook portions 54 of the corresponding healds 46B. Further, since the endless belt 62 is moved in accordance with the reciprocal upward and downward displacement of the holding member 47, when the endless belt 62 is moved in the direction shown by an arrow D1 in Fig. 10, due to the upward displacement of the holding plate 47, the hook member 66b is able to engage with the hook portion 54 of one of the healds 46B, and when the endless belt 62 is moved in the direction of the arrow D2 in Fig. 10, due to the downward displacement of the holding member 47, the hook member 66a is able to engage with the hook portion 54 of one of the healds 46A. Since the arrangement of the hook members 66a and 66b can be made in the same manner as explained with reference to the first embodiment, while considering the above-mentioned mechanism having the double alignment of healds 46A and 46B as mentioned above, a detailed explanation thereof is omitted. The mechanism explained with reference to the second embodiment can be used to drive the plate cams 59, but as shown in Fig. 10, a different mechanism can be applied. Namely, the cam plate 59 is rigidly mounted on a horizontal shaft 59a to which a pinion wheel 59b is secured, and the pinion wheel 59b is driven by a bevel gear mechanism 67 which is driven by a shaft 68, which, in turn, is synchronously driven by a main shaft of the circular loom via a power transmission mechanism (not shown) to insert one of the shuttles (when producing a tubular fabric having an eight healds satin weave structure, four shuttles are utilized). As mentioned above, the tubular fabric having a satin weave structure can be also produced by applying the above-mentioned modifications of the shed-forming mechanism to the conventional circular loom, and thus the present invention contributes to an improvement of the quality of the tubular fabric, particularly for industrial use. In the above description, the shed-forming mechanism is used particularly to produce a tubular fabric provided with a satin weave structure, and only the above-mentioned principle of forming sheds for creating a satin weave structure is disclosed. Nevertheless, this principle of forming a unit shed for creating a one repeat weave structure as mentioned above can be applied to the production of a tubular fabric having a weave structure other than a plain weave structure, such as a twill structure and other complicated plain weave structures.

Claims: A shed-forming arrangement for a circular loom provided with: a plurality of healds (46) disposed in a circular array, an annular reed member (25) located within said array of healds, means (17) for supplying warps (W) to said healds, said supplying means being disposed outside said array, each of said healds being provided with an eye for threading a warp supplied from said supply means, and shuttles (13) arranged to move along an annular passage defined by said reed member, said shed-forming arrangement comprising a plurality of shed-forming mechanisms (45) arranged to be disposed between said supply means and said reed member and coupled to respective groups of said healds, whereby in use a weft taken out from each of said shuttles is inserted into successive sheds created by motion of said healds out of the plane of said annular passage before the arrival of said shuttle, and said weft is interwoven with warps to form a tubular fabric having a predetermined weave structure, characterised in that the shed-forming arrangement is arranged to move the healds (46) of each group selectively to form said successive sheds in a repeating pattern in which successive wefts (F) cross different warps (W), whereby a repeating weave structure is formed, the number of warps in each group being equal to the number of warps in one repeat of the weave structure. A shed-forming arrangement according to claim 1 which is arranged to form a satin weave structure by individually displacing each heald (46) relative to the other healds of its group in a repeating pattern. A circular loom comprising a shed-forming arrangement according to claim 1 or claim 2 and a cylindrical cam mechanism (29) mounted on an upright main drive shaft (24) of the loom, said cam mechanism having an annular cam (29a) which raises or lowers a cam-follower arrangement (47,49a,49b) as the cam mechanism rotates, said cam-follower arrangement being arranged to catch said healds (46) and thereby move them in an upward and downward direction to form said sheds, the catching of the healds being controlled by a selective actuating means (50,51,53,54;59,60) which ensures that the healds of each group are moved selectively to form said successive sheds. A circular loom according to claim 3 wherein said actuating means comprises a rotatable control cylinder (50) having a plurality of catching members (53) disposed on its cylindrical surface and arranged to catch respective healds (46) as the cylinder rotates, said control cylinder being provided with a ratchet wheel mechanism which is coupled to said cam-follower arrangement (47,49a,49b) and indexes the control cylinder to cause selected healds to be caught and to form said successive sheds. A circular loom according to claim 3, wherein said cam-follower arrangement (47,49a,49b) includes a catching member (47) which catches a projecting portion (54) of each heald (46) in the path of the catching member, each heald being supported by a sliding pivot (57a) which enables the heald to swing away from the path of the catching member and each heald engaging a respective cam (59) of a multiple cam arrangement (59,60) which is cam arrangement indexed to displace a selected heald from the path of the catching member as each successive shed is formed. A circular loom according to claim 3, wherein each group of healds (46) comprises a radially inner sub-group (46A) aligned with a radially outer sub-group (46B), said cam-follower arrangement (47,49) being arranged to drive two catching members (66a,66b) which can catch healds of the inner sub-group (46A) and outer sub-group (46B) respectively, said catching members being arranged to move in opposite directions whereby healds of the inner sub-group (46A) and outer sub-group (46B) are caught alternately, each heald being supported by a sliding pivot (57a) which enables the heald to swing away from the path of its associated catching member (66a,66b) and each heald engaging a cam (59) of a multiple cam arrangement which cam arrangement is indexed to displace selective healds from the path of their associated catching members as each successive shed is formed. A circular loom according to claim 6 wherein said catching members (66a,66b) are mounted on an endless belt (62) which includes a loop extending upwardly between said sub-groups (46A,46B) of healds (46) and is driven in a reciprocating manner by said cam-follower arrangement (47,49a,49b). A circular loom according to any of claims 5 to 7 wherein each heald (46) is supported by spring means (55) and said pivot (57a) slides in a slot as the heald is caught by a catching member (47;66a,66b) or released and returned to its original position by said spring means.

Inventors: HIRAMATSU SATORU C O TORII WIN, HIRAMATSU, SATORU, C/O TORII WINDING MACHINE CO.
Applicants: TORII WINDING MACHINE CO, TORII WINDING MACHINE CO., LTD.
Application year: 1990
Main classification: D03D37
IPC codes: D03C13, D03D37, D03C5