Title of Invention	A DUCT ELEMENT
Abstract	The present invention relates to a structure of a duct element capable of facilitating the work involved to interconnect a number of duct elements to construct a duct assembly for a pneumatic clearer of a spinning machine while preventing torsion as well as longitudinal deviation occurring in the duct assembly to such extent that substantially no disturbance is brought about in the proper positioning of a flute when the duct assembly is installed. The duct element is constituted by a first component member forming a bottom wall thereof and a second component member forming other walls thereof. The first component member has longitudinal sides with U-like bent portions. End faces of the bent portions serve as longitudinal positioning portions in assembling the duct elements into a duct assembly.

Title of Invention

A DUCT ELEMENT

Abstract

The present invention relates to a structure of a duct element capable of facilitating the work involved to interconnect a number of duct elements to construct a duct assembly for a pneumatic clearer of a spinning machine while preventing torsion as well as longitudinal deviation occurring in the duct assembly to such extent that substantially no disturbance is brought about in the proper positioning of a flute when the duct assembly is installed. The duct element is constituted by a first component member forming a bottom wall thereof and a second component member forming other walls thereof. The first component member has longitudinal sides with U-like bent portions. End faces of the bent portions serve as longitudinal positioning portions in assembling the duct elements into a duct assembly.

Full Text	BACKGROUND QF THE TNVEMTTON Field of the Invention The present invention relates to a duct element which constitutes a portion of a duct assembly for use in a spinning machine, such as a fine spinning frame or the like, provided with a pneumatic clearer. Description of Related Art In general, the spinning machine {also referred to as the spinning frame) is equipped with a pneumatic clearer for positively catching fleece delivered from a draft part upon end breakage to prevent the fleece from adversely affecting spindles other than those suffer from the end breakage (yarn breakage). In order to better understand the invention, the prior art thereof will first be described in detail. Figure 12 is a view showing a known pneumatic clearer. Referring to Fig. 12, each pneumatic clearer is composed of a duct assembly 31 disposed so as to extend in the longitudinal direction of the machine frame (i.e., the direction perpendicular to the plane of the drawing) and a flute 33 connected to the duct assembly 31 by way of a suction pipe 32. The duct assemblies 31 are coupled to a suction box (not shown) disposed at one end portion of the frame. On the other hand, the flute 33 is disposed along a front bottom roller 34 and includes intake ports formed at locations corresponding to yarn paths for yarns leading from a draft portion 35 to respective cops . A single nozzle type pneumatic clearer is also known in which suction nozzles are provided corresponding to individual yarn paths, respectively, in place of the flute. The duct assembly 31 is constituted by a plurality of duct elements interconnected in the longitudinal direction of the frame and disposed on a rest portion 36a of a spring piece 36. Methods for connecting the duct elements together to form the duct assembly include, for example interconnecting the duct elements by means of coupling members interposed therebetween, and a method in which each of the duct elements is formed with a taper along the longitudinal axis and a smaller diameter portion of a given duct element is snugly fit into larger diameter portion of an adjacent duct element. In the latter method, if necessary, an adhesive tape may be wound around the lap-joint portion between the duct elements . In general, each of the individual duct elements is formed as a hollow box-like (or conduit) by bending a metal sheet and joining free edge portions thereof together with a tongue and groove joint 37 , as shown in Fig. 13 . More specifically, the tongue and groove joint 37 comprises a male mating portion 37a formed by bending a free edge portion of a metal sheet at a right angle and a female mating portion 37b formed along the other free edge portion of the metal sheet to receive the male mating portion 3 7a, as can be clearly seen in Fig. 13. After inserting the male mating portion 3 7a into the female mating portion 37b, the latter is pressed in the thickness direction thereof. In general, to facilitate transportation and assembly of a spinning machine, the frame body of the spinning machine is manufactured as a plurality of discrete frame units each having a predetermined length. Subsequently, these frame units are transported to a customer"s spinning mill to be assembled into a spinning machine by combining the frame units together. To this end, the duct element portions of the duct assembly are formed in a length of about 2 meters to facilitate their transportation. In this case, seven or eight duct elements will be required to construct a duct assembly disposed at one side of a frame of a spinning machine having 200 spindles installed at each side. Nevertheless, the expenditure involved to transport the duct elements is high because of their large bulk. Under the circumstances, Japanese Patent Application Laid-open No. 9-53766 (JP-A-9-53766} proposes a box-like structure of a duct element for a spinning machine which is constituted by a plurality of planar component members of the same shape formed by cutting a blank sheet material in an appropriate size and shape so that the component members can be stacked onto one another to reduce the transportation cost. As is well known in the art, a spinning machine frame is very long. Consequently, when the duct assembly for the spinning machine is manufactured in the form of a plurality of duct elements each of a certain length (about 2 meters) to facilitate the transportation thereof, a large number of duct elements have to be interconnected. When the method of interconnecting the duct elements by using coupling members interposed therebetween is adopted, in addition to the necessity to prepare the coupling members, the troublesome work of fitting the duct elements and the coupling members together is required. Consequently, the cost of installing the duct assembly increases significantly. On the other hand, the method of interconnecting the duct elements by forming each of the duct elements with a tapered structure and fitting the smaller diameter portion of one duct element into the larger diameter portion of an adjacent duct element can certainly facilitate the work of assembling the duct elements, provided that the individual duct elements are each formed with a uniform wall thickness. However, since each of the duct elements of the duct assembly are generally provided with the female mating portion 37b extending in the longitudinal direction, as previously mentioned herein (see Figs. 12 and 13), the wall thickness thereof is increased in the region of the female mating portion 37b. Consequently, fitting the smaller diameter portion of one duct element into the larger diameter portion of the adjacent one gives rise to a large force acting on the female mating portion 37b in a region where the duct elements are engaged with each other, which in turn gives rise to torsion in the duct elements. Even if the torsion in each duct element is of a small magnitude, it becomes very large in the duct assembly which is constituted by a large number of the duct elements. As a result, the portion of the flute 33 connected to the duct assembly 31 by way of the suction pipe 32 may deviate from a predetermined desired position. Moreover, with the method of interconnecting the duct elements by fitting the smaller diameter portion of a duct element into the larger diameter portion of an adjacent one, difficulty is encountered property in positioning the duct assembly properly in the longitudinal direction. More specifically, when deviation in the longitudinal direction increases due to the interconnection of a large number of duct elements through the fitting procedure mentioned above, the position of the flute 33 coupled to the duct assembly 31 by way of the suction pipe 32 will be displaced from the predetermined desired position. SUMMARY OF THE TNVEHTIOH In light of the state of the art described above, it is an object of the present invention to provide a duct element with an improved structure which is suitable for constructing a duct assembly for a pneumatic clearer of a spinning machine by using a number of such duct elements, and which can facilitate the work or processes involved in interconnecting the duct elements while preventing torsion and longitudinal deviation in a duct assembly to such an extent that substantially no disturbance is brought about in the proper positioning of a flute or pneumatic nozzles. In view of the above and other objects which will become apparent as the description proceeds, there is provided according to a general aspect of the present invention a duct element with a hollow box-like shape constituting a portion of a duct assembly for a spinning machine, wherein a plurality of the duct elements are interconnected by fitting a first end portion of a given duct element into a second end portion of another adjacent duct element to thereby constitute the duct assembly. The duct element includes a pair of component members corresponding to two halves of the box-like duct element. Each component member is provided with mating portions at opposite sides with reference to a plane extending substantially through a center of the duct element and intersecting substantially orthogonally both ends of the duct element so that the component members can be joined air-tightly when used together, and positioning portions for regulating a length of a lap-joint portion, formed longitudinally when a first end portion of one duct element is fit into a second end portion of another duct element, to a predetermined amount. With the structure described above, a duct element with a hollow box-like form is constructed by joining the two component members together by engaging the mating portions thereof so that they are airtight when the duct operates. Duct elements are interconnected by inserting a first end portion of one duct element into a second end portion of another duct element. The length of the lap-joint portion formed longitudinally between the interconnected duct elements is regulated to a predetermined amount by the positioning portions, when the duct elements are interconnected, since the mating portions are formed at opposite sides with reference to a plane extending substantially through the center of the duct element and intersecting substantially orthogonally both ends of the duct element, even if a force acts torsionally at each mating portion of a duct element, both duct elements cancel out each other"s torsion and hence torsion in the duct assembly is thereby prevented. In a preferred mode of carrying out the invention, the mating portions may be formed symmetrically to each other with reference to a plane which extends substantially through a center of the duct element and intersects substantially orthogonally both ends of the duct element. By virtue of the structure described above, the duct elements and hence the duct assembly can be more reliably protected against torsion. In another preferred mode of carrying out the invention, the duct element may be arranged so as to be divided into a first component member constituting a bottom wall and a second component member constituting an other wall or walls. With the duct element structure described above, forming mating portions symmetrical with reference to the plane extending through a center of the duct element and intersecting orthogonally both ends thereof is facilitated, because the first component member constitutes the bottom wall of the duct element. In yet another preferred mode of carrying out the invention, the mating portions of the first component member may be formed longitudinally at both sides of the first component member in the form of roughly U-shaped bent portions having grooves such that the mating portions of the second component member comprising bottom portions of the front and rear wall are insertable therein. With the duct element structure described above, the lower end portions of the second component member are positioned opposite the mating portions of the first component member and the second member is assembled onto the first member from above. In still another preferred mode of carrying out the invention, both component members are joined together with both lower end portions of the second component member press-fit into the bent portions of the first component member. Accordingly, the air-tightness of the mating portions or joints can be ensured without resorting to a bending or caulking process after assembling the first and second component members. In a further preferred mode of carrying out the invention, the mating portions of the component members may be formed in shapes such that the component members can be joined together by moving one of the component members in a direction orthogonal to a longitudinal direction of the other component member. Since, the first and second component members can be joined together fay simply moving one of the component members toward the other component member, the work of assembling the duct elements is facilitated. In a yet further preferred mode of carrying out the invention, the positioning portions are formed by removing a portion of the mating portions corresponding to a lap-joint portion formed when the duct elements are interconnected. Thus, the positioning portions can be easily formed. Further, because the end of one duct element contacts the positioning portion of the adjacent duct element when the duct element are connected, the longitudinal length of the lap-joint portion is limited to a predetermined amount. In a still further preferred mode of carrying out the invention, at least the portion of one duct element that is fit into the end portion of another duct element when the duct elements are interconnected to construct the duct assembly, is formed with a gradual taper in the downstream direction of the air flow. Consequently, interconnection of the duct elements is facilitated and fleece or the like can be transported smoothly without being caught or trapped at the joint portions within the duct assembly. Further, according to another aspect of the invention, there is provided a box-like duct assembly which is constituted by interconnecting a plurality of the duct elements described above. Accordingly, the present invention provides a duct element of a hollow box-like shape constituting a part of a duct assembly for a spinning machine, wherein a plurality of said duct elements are interconnected by fitting a first end portion of one of said duct elements into a second end portion of another adjacent duct element to thereby construct said duct assembly, comprising; a pair of component members corresponding to two divisions of said box-like duct element, each of said component members being provided with mating portions respectively, at opposite sides with reference to a plane extending substantially through a center of said duct element and intersecting substantially orthogonally both ends of said duct element so that said component members are joined together fluid-tightly in the state of usage by engaging said mating portions with each other; and positioning portions for regulating to a predetermined amount a longitudinal length of a lap-joint portion formed when a first end portion of one of said duct elements is fit into a second end portion of another duct element upon assembly of said duct assembly. The above and other objects, features and attendant advantages of the present invention will be more easily understood by reading the following description of the preferred embodiments thereof taken, only by way of example, in conjunction with the accompanying drawings. BRIKF DESCRIPTTON OF THE DRfiWTNGS In the course of the description which follows, reference is made to the drawings, in which: Fig. 1 is a partially sectional perspective view showing a structure of a duct element according to a first embodiment of the invention; Fig. 2 is a perspective view showing assembled duct elements of the invention; Fig. 3(a) is a fragmentary front view showing duct elements in an interconnected state; Fig. 3 (b) is a fragmentary bottom plan view showing duct elements in an interconnected state; Fig. 4 is a schematic diagram showing duct elements in an interconnected state; Fig. 5 is a side elevational view of a duct element according to another embodiment of the present invention; Fig. 6 is a side elevational view of a duct element according to yet another embodiment of the invention; Fig. 7 is a side elevational view of a duct element according to still another embodiment of the invention; Fig. 8 is a side elevational view of a duct element according to a further embodiment of the invention; Fig. 9 is a side elevational view of a duct element according to yet a further embodiment of the invention; Fig. 10 is a side elevational view of a duct element according to a still further embodiment of the invention; Fig. 11(a) is a schematic view showing a connected state of duct elements according to another embodiment of the invention; Fig. 11(b) is a schematic view showing a connected state of duct elements according to a further embodiment of the invention; Fig. 12 is a fragmentary side elevational view showing a structure of a known pneumatic clearer; and Fig. 13 is a side view showing a conventional duct element. nKSCRIPTTON OF THE PREFERRFin FMB0DTMEHT5 The preferred embodiments of the present invention will now be described in detail with reference to the drawings . In the following description, like reference characters designate like or corresponding parts. Also in the following description, it is to be understood that terms such as "left", "right", "top", ■•bottom", "front", "rear", "box-like", "diameter" and the like are words of convenience and are not to be construed as limiting terms. Embodiment 1 Now, referring to Figs. 1 to 4, description will be made of a first embodiment of the present invention. As is shown in Figs. 1 and 2, each duct element 1 is constituted by a pair of component members 2 and 3 in the form of a sleeve or hollow box of a substantially pentagonal cross-section. Each of the component members 2 and 3 is formed by bending, for example, a metal sheet having a thickness of about 1 mm, wherein the first and second component members 2 and 3 are formed with shapes such that the duct element 1 is divided into two halves along a plane which extends to orthogonally intersect both ends thereof. The duct element 1 has a length of about 2 meters and is tapered such that the cross-sectional area thereof increases gradually from a first end (right end as viewed in Fig. 2) toward a second end (left end as viewed in Fig. 2). Thus, according the present embodiment, when a duct assembly constituted by assembling a plurality of duct elements is installed in a spinning machine, the first end of each above mentioned duct element is located at a downstream side of the air flow while the second end is located at a upstream side of the air flow. The difference between the diametrical size of the first and second ends of the duct element 1 substantially corresponds to the sum of the wall thickness of the first component member 2 and the second component member 3. By way of example, if the duct element has a diametrical size, e.g. height of 200 mm at the first end (right end in Fig. 2), the diametrical size or height at the second end (left end in Fig. 2) would be about 202 mm as shown in Fig. 4. The base member ( first component) 2 includes a plate portion 2a which constitutes a bottom wall of the duct element 1. A female bent portion 2b is formed along each longitudinal side of the plate portion 2a. More specifically, each female bent portion 2b is bent or folded so as to form a substantially U-like groove 2c for receiving a bottom edge portion of the hood-like member 3. The hood-like member (second component) 3 is comprised of a front wall la, a suction-pipe mounting wall lb, a top wall Ic and a rear wall Id which are continuously formed by bending a metal sheet. More specifically, the front wall la and the rear wall Id extend in parallel with each other and have respective lower end portions which are formed so as to lie on a plane which extends substantially in parallel with the top wall Ic. The suction-pipe mounting wall lb is formed with through-holes 4 for mounting a suction pipe thereat (not shown). A number of such through-holes 4 of appropriate size may be provided depending on the type of pneumatic clearer to be employed, i.e., flute type or single nozzle type. That is, the duct element 1 can be employed in combination with a flute type pneumatic clearer or a single-nozzle type pneumatic clearer. Referring to Fig. 1, the base member (first component) 2 is provided with notches 5a and 5b at both ends thereof, respectively, which are formed by partially removing the material of the female bent portions 2b. The end faces of the female bent portion 2b resulting from formation of the notches 5a and 5b serve as positioning portions 6, respectively. A portion of the base plate 2a held between the notches 5b provided at the second end of the duct element 1 mentioned previously is formed so that the width thereof gradually decreases toward the second end. When the component members 2 and 3 are joined together, as shown in Fig. 2, front and rear lower end male portions 3a of the hbod-like member ( second component) 3 project outwardly from the female bent portions 2b, respectively, of the base member (first component) 2, Next, the description will turn to assembly of the duct element 1 described above and assembly of a duct assembly. Upon assembling the duct element 1, the base member (first component) 2 and the hood-like member (second component) 3 are disposed so that both lower end male portions 3a of the hood-like member 3 are positioned opposite the grooves 2c of the base member 2, whereupon the hood-like member 3 is pressed downwardly from above. As a result, both the lower end male portions 3a of the hood-like member 3 are inserted into the grooves 2c, respectively, and the component members 2 and 3 are secured together. On the other hand, to construct a duct assembly by interconnecting the duct elements 1 thus formed, the first end portion (reduced diameter portion) of one duct element 1 is inserted into the second end portion (larger diameter portion) of another duct element 1. In this state, the front wall la, the suction-pipe mounting wall lb, the top wall Ic, the rear wall Id and the bottom wall of the one duct element 1 at the first end portion thereof are positioned inside the front wall la, the suction-pipe mounting wall lb, the top wall Ic, the rear wall Id and the bottom wall, respectively, of the other duct element 1, as csn be seen in Figs. 3(a) and 3(b). Since the hood-like member (second component) 3 has no overlapping bent portion in the thickness direction thereof, the first end portion of the one duct element 1 can be fit into the second end portion of the other duct element 1 without any appreciable difficulty. On the other hand, the base member (first component) 2 has the female bent portions 2b overlapping in the thickness direction thereof. Consequently, if the female bent portions 2fa extend over the entire length of the second component member 2, the female bent portions 2b provide an obstacle to the insertion of the first end portion of the one duct element 1 into the second end portion of the other duct element 1. However, with the duct element 1 according to this, both of the duct elements 1 to be coupled together are provided with the notches 5a and 5b, respectively, at locations corresponding to the portions where the duct elements are connected to each other. Since the female bent portions 2b at these portions are deleted, when the duct elements 1 are interconnected by inserting the reduced diameter portion of one duct element 1 into the large diameter portion of another one, the female bent portions 2b of the base member 2 provide no obstacle. Furthermore, both the lower end male portions 3a of the hood-like member (second component) 3 located at the first end (downstream side) of one duct element 1 bear against the positioning portions 6, respectively, which are formed at the second end {upstream side) of the base member {first component) 2 of the other duct element 1 upon insertion of the one duct element 1 into the other duct element 1, while both the lower end male portions 3a of the hood-like member 3 located at the second end of the one duct element 1 bear against the positioning portions 6, respectively, which are formed at the first end of the base member 2 of another duct element 1. In this way, the length of the lap-joint region or portion in the longitudinal direction of the interconnected duct elements 1 can be limited to a predetermined amount. The structure of the duct element described above enjoys advantageous effects which will now be mentioned below. (a) when a plurality of duct elements 1 are telescopically interconnected by inserting the reduced diameter portion of one duct element into the larger diameter portion of another duct element to thereby assemble a duct assembly after having assembled each tapered duct element by engaging the mating portions (lower end male portions 3a and female bent portions 2b) extending longitudinally along the two component members 2 and 3, respectively, the mating portions, overlapping in the direction of the thickness of the duct element 1, do not overlap each other. Consequently, since a force does not act torsionally on the duct element 1, torsion in the individual duct elements, and hence in the duct assembly, is prevented, (b) Upon interconnection of the duct elements 1, the length of the lap-joint portion or region in the longitudinal direction of the duct element 1 can be limited to a predetermined amount due to the action of the positioning portions 6 provided at both ends of the duct element 1, and deviations in the longitudinal direction, of the interconnected duct elements, large enough to hinder the desired positioning of the flute or pneumatic nozzles are prevented. (C) Assembly of the duct element 1 can be carried out very simply by merely fitting one mating portion (lower end male portion 3a) into the other (female bent portion 2b). Moreover, even when the thickness of the lower end male portion 3a is smaller than the width of the female groove 2c and there is a gap between the lower end male portion 3a and the female bent portions 2b, when the front wall la and the rear wall Id are pushed inwardly by application of a negative pressure to the duct assembly from a vacuum source ( not shown) , the lower end male portion 3a is caused to bear on the female bent portions 2b, and air-tightness can thereby be ensured. (d) When a plurality of duct elements 1 are connected by inserting the smaller end of one duct element 1 into the lager end of another duct element, the positioning portion 6 can be automatically formed by removing a predetermined length from the female bent portions 2b such that the mating portions, when combined, do not overlap each other in the direction of the thickness of the duct element 1. (e) since the duct element 1 is constituted by the first component member 2 serving as the base member forming the bottom wall and the second component member 3 forming the other walls of the duct element, compared to the construction wherein mating portions are formed midway on front wall la and rear wall lb the inner wall surface of the duct element 1 can be formed flat, and it becomes difficult for fly waste and fibers to remain midway in the duct assembly. { f) Interconnection of the duct elements is facilitated due to their tapered structure. {g) Since an end portion of the duct element 1 is formed with a taper that gradually decreases toward the downstream side of the duct assembly, when the duct elements are interconnected to construct the duct assembly, fleece or the like can be transported smoothly without being caught by or trapped at the joint portions within the duct assembly. The present invention is not limited to the above mentioned embodiment, but may also embodied as described below. Embodiment 2 A second embodiment of the present invention will be described with reference to Fig. 5. According to the second embodiment, with the lower male portions 3a of the second component member not inserted, each female bent portion 2b formed integrally with the first component member {base member) 2 with a substantially U-shape in cross-section may be formed so that width gaps at top portions of the female bent portions 2b are smaller than the thicknesses of the lower end male portions 3a, and the lower end male portions 2a are then press fit into the female bent portions 2b. In this case, with the lower end male portions inserted into the female portions 2b, the first component member (base member) 2 and the second component member (hood-like member) 3 can be positively joined together in an air-tight manner. Embodiment 3 As shown in Fig. 6, instead of the construction wherein the structure of the mating portions is such that the lower end male portions are inserted into the grooves 2c mating members 2d are foldedly formed at both sides of the first component member 2 as inward facing convex are surfaces. On the other hand, mating members 3b are formed at lower end surface portions of the second component member 3 so as to be engageable with the mating members 2d, respectively, of the first component member. Also according to the structure of this embodiment, portions of the mating members 2d, corresponding to the area where they overlap when the duct elements 1 are connected, are removed at both end portions of the first component member 2 . In this case, both the mating members 2d and 3b exhibit resiliency, and the first component member (base member) 2 and the second component member (hood-like member) 3 can be simply assembled by pressing the second component member (hood-like member) 3 onto the first component member (base member) 2 from above. Each of the mating members 2d and 3b may also be formed as outward facing convex arc surfaces, respectively, with substantially the same effect as the structure shown in Fig. 6. Embodiment 4 The mating portions are not necessarily restricted to shapes which are symmetrical to each other with reference to a plane extending substantially through a center of the duct element 1 and intersecting substantially orthogonally both the ends of the duct element 1. That is mating portions of different types may be disposed at opposite sides with reference to a plane extending substantially through a center of the duct element and intersecting substantially orthogonally both the ends of the duct element. Figure 7 shows a structure of a duct element according to a fourth embodiment of the present invention. As can be seen in the figure, the first component member (base member) 2 is provided with a female bent portion 2b at a side corresponding to the front wall la, while a mating member 2d is formed at the opposite side corresponding to the rear wall Id that it presents an inward facing convex arc surface. On the other hand, a lower end male portion 3a is formed at the front wall la of the second component member (hood-like member) 3 and a mating member 3b is formed at a lower portion thereof in a complementarily arcuate shape so as to be engageable with the mating member 2d of the first component member (base member) . Also according to the structure of this embodiment, portions of the female bent portions 2b and the mating members 2d, corresponding to the areas where they overlap, respectively, when the duct elements 1 are connected, are removed at both end portions of the first component member 2 . The structure of the duct element according to the present embodiment obtains advantageous effects similar to those of the first embodiment. Embodiment 5 The mating portions need not necessarily be provided at both sides of the bottom wall. They may be provided at top and bottom sides of the duct element 1. For example, as can be seen in Fig. 8, a duct element 1 according to the instant embodiment is comprised of a first component member 10 and a second component member 11 which comprise the front wall la, the suction-pipe mounting wall lb, the top wall Ic and a bottom wall le. Bent portions 10b having grooves 10a for receiving mating members 11a of the second component member 11 are formed at top and bottom sides of the first component member 10. Also according to the structure of this embodiment, portions of the bent portions 10b formed at the first component member 10, corresponding to the area where they overlap when duct elements 1 are connected, are removed at both end portions of the first component member 10. The structure of the duct element according to the present embodiment obtains advantageous effects similar to those of the first embodiment. Embodiment 6 The present invention can find application not only to the duct assemblies installed at both lateral sides of a frame but also to the duct assembly to be installed longitudinally at the center of a frame. For example, figure 9 shows a duct element 1 which has a hexagonal cross-section. As can be seen in the figure, bent portions 7b having grooves 7a for receiving mating members 8a of a second component member 8 are formed at both top sides, respectively, of a first component member 7 at bottom, and mating members 8a at both bottom sides of the second component member 8 project horizontally. According to the structure of this embodiment of the present invention, portions of the bent portions 7b of the first component member 7, corresponding to the area where they overlap when the duct elements are connected, are removed at both end portions of the first component member 7. In the present embodiment, the first component member 7 and the second component member 8 can fit inside each other, which allows these component members to be packaged efficiently. Consequently, the packaging and transportation costs can be advantageously reduced. As a modification of the present embodiment, the mating members 8a provided at bottom sides of the second component member 8 may be formed so as to extend downwardly while the bent portions 7b of the first component member 7 may be formed so that the grooves 7a are oriented upwardly to receive therein the downwardly extending mating members 8a. Embodiment 7 Figure 10 shows a duct element according to a seventh embodiment of the present invention. The mating portions for joining the first and second component members together need not necessarily be disposed on the exterior of the duct elements. It is equally possible to provide the mating portions in the interior of the duct elements as shown in Fig. 10. More specifically, the lower end portions of the second component member 3 are bent inwardly to form bent male portions 3c, while female mating portion 9a are formed at both sides of a first component member 9. In this case, the female mating portions 9a are not notched, the duct elements are connected in the state where the mating portions overlap each other. Consequently, when a plurality of tapered duct elements are interconnected for realizing a duct assembly, a force may act to bring about torsion in the individual duct elements at the locations where the mating portions or joints overlap each other in the thickness direction thereof. However, since the mating portions or joints are formed symmetrically to each other with reference to a plane extending substantially through a center of the duct element and orthogonally intersecting both end faces of the duct element, the forces acting on the duct elements are mutually canceled out, whereby torsion in the duct elements, and hence the duct assembly, can be prevented. With the structure of the duct element according to this embodiment of the present invention, it is necessary to provide the positioning ineans for limiting the longitudinal length of the lap-joint portion formed upon interconnection of the duct elements separately. As such positioning means, for example, a stopper member may be formed on an external surface of the duct element in the vicinity of the smaller diameter end of the duct element. Many features and advantages of the present invention are apparent from the detailed description and thus it is intended by the appended claims to cover all such features and advantages which fall within the true spirit and scope of the invention. Further, since numerous modifications and combinations will readily occur to those skilled in the art, it is not intended to limit the invention to the exact construction and operation described. By way of example, the duct element 1 of the present invention is not restricted to any particular shape or geometrical configuration. What is essentially required is that the duct element be of a hollow-box or sleeve-like form and that the duct elements can be interconnected by inserting a first end portion of a given duct element into a second end portion of another duct element to construct a duct assembly. Thus, it is not necessarily required that the duct element be tapered so that the cross-sectional area thereof increases gradually from the first end toward the second end thereof so long as the requirements mentioned above can be satisfied. By way of example, the duct element may be tapered at both end portions thereof with an intermediate portion having a constant cross-sectional area, as illustrated in Fig. 11 (a) . Alternatively, the intermediate portion of the duct element may be tapered with both end portions thereof being formed with constant cross-sectional areas, as illustrated in Fig. 11(b). Needless to say, the length of the duct element 1 may be shorter or longer than two meters. Application of the present invention is not limited to the duct elements and duct assembly for a ring spinning machine. The teachings of the present invention may be equally applied to duct assemblies for flyer frames and other types of spinning frames. Furthermore, in the structure of the duct element shown in Fig. 6, the mating members 2d and the mating members 3b may be formed so as to exhibit a spring action, and the duct element can be realized by simply pressing the second component member onto the first component member from above. Accordingly, all suitable modifications and equivalents may be resorted to, falling within the spirit and scope of the invention. WE CLAIM: 1. A duct element of a hollow box-like shape constituting a part of a duct assembly for a spinning machine, wherein a plurality of said duct elements are interconnected by fitting a first end portion of one of said duct elements into a second end portion of another adjacent duct element to thereby construct said duct assembly, comprising: a pair of component members (2, 3) corresponding to two divisions of said box-like duct element, each of said component members (2, 3] being provided with mating portions (2b, 3a) respectively, at opposite sides with reference to a plane extending substantially through a center of said duct element and intersecting substantially orthogonally both ends of said duct element so that said component members are joined together fluid-tightly in the state of usage by engaging said mating portions (2a, 3b) with each other; and positioning portions (6) for regulating to a predetermined amount a longitudinal length of a lap-joint portion formed when a first end portion of one of said duct elements is fit into a second end portion of another duct element upon assembly of said duct assembly. 2. The duct element for a spinning machine according to claim 1, wherein said mating portions (2b, 3a) are formed symmetrically to each other with reference to a plane which extends substantially through a center of said duct element (1) and intersects substantially orthogonally both ends of said duct element (1). 3. The duct element for a spinning machine according to claim 1, wherein said duct element (1) is divided into a first component member (2) constituting a bottom wall and a second component member (3) constituting other walls* 4. "The duct element for a spinning machine according to claim 3, wherein the mating portions of said first component member (2) are formed longitudinally at both sides of said first component member (1) in the form of U-shaped bent portions (2b) having grooves (2c), respectively, and wherein the mating portions of said second component member (3) are constituted by lower end portions (3a) of a front wall (la) and a rear wall (Id), respectively, which are insertable in said grooves (2c) of said U-shaped bent portions (2b) of said first component member (2). 5. The duct element for a spinning machine according to claim 4, wherein both component members (2, 3) are joined together to form a duct element {1) in a state where both lower end portions (3a) of said second component member (3) are press-fit into said bent portions (2b) of said first component manner (2), respectively. 6. The duct element for a spinning machine according to claim 1, wherein said mating portions (2b, 3a) of said component members (2, 3) are formed in shapes such that both of said component members (2, 3) may be joined together by moving one of said component members relative to the other in a direction orthogonal to a longitudinal direction of said component members (2, 3). 7. The duct element for a spinning machine according to any one of the preceding claims, wherein said positioning portions (6) are formed with portions of said mating portions that correspond to lap-joint portions, formed when one duct element (1) is telescopically inserted into an other duct element to form a duct assembly, removed. 8. The duct element for a spinning machine according to any one of the preceding claims, wherein said duct element (1) is longitudinally tapered so that said duct element (1) has a reduced diameter end portion and a larger diameter end portion, and wherein said duct assembly is constituted by inserting telescopically said reduced diameter portion Qf one duct element into said larger diameter portion of another duct element, said reduced diameter end portions of said duct elements being positioned downstream of a fluid flow of said duct assembly. 9. A duct assembly of a hollow box-like form for a spinning machine constituted by interconnecting a plurality of duct elements (1) as claimed in any one of claims I to 8. 10. A duct element substantially as herein described with reference to figures 1 to lib of the accompanying drawings.

Full Text

BACKGROUND QF THE TNVEMTTON Field of the Invention
The present invention relates to a duct element which constitutes a portion of a duct assembly for use in a spinning machine, such as a fine spinning frame or the like, provided with a pneumatic clearer. Description of Related Art
In general, the spinning machine {also referred to as the spinning frame) is equipped with a pneumatic clearer for positively catching fleece delivered from a draft part upon end breakage to prevent the fleece from adversely affecting spindles other than those suffer from the end breakage (yarn breakage). In order to better understand the invention, the prior art thereof will first be described in detail. Figure 12 is a view showing a known pneumatic clearer. Referring to Fig. 12, each pneumatic clearer is composed of a duct assembly 31 disposed so as to extend in the longitudinal direction of the machine frame (i.e., the direction perpendicular to the plane of the drawing) and a flute 33 connected to the duct assembly 31 by way of a suction pipe 32. The duct assemblies 31 are coupled to a suction box (not shown) disposed at one end portion of the frame. On the other hand, the flute 33 is disposed along a front bottom roller 34 and includes intake ports formed at locations corresponding to yarn paths for yarns leading from a draft portion 35 to respective cops . A single nozzle type pneumatic clearer is also known in which suction nozzles are provided

corresponding to individual yarn paths, respectively, in place of the flute.
The duct assembly 31 is constituted by a plurality of duct elements interconnected in the longitudinal direction of the frame and disposed on a rest portion 36a of a spring piece 36. Methods for connecting the duct elements together to form the duct assembly include, for example interconnecting the duct elements by means of coupling members interposed therebetween, and a method in which each of the duct elements is formed with a taper along the longitudinal axis and a smaller diameter portion of a given duct element is snugly fit into larger diameter portion of an adjacent duct element. In the latter method, if necessary, an adhesive tape may be wound around the lap-joint portion between the duct elements . In general, each of the individual duct elements is formed as a hollow box-like (or conduit) by bending a metal sheet and joining free edge portions thereof together with a tongue and groove joint 37 , as shown in Fig. 13 . More specifically, the tongue and groove joint 37 comprises a male mating portion 37a formed by bending a free edge portion of a metal sheet at a right angle and a female mating portion 37b formed along the other free edge portion of the metal sheet to receive the male mating portion 3 7a, as can be clearly seen in Fig. 13. After inserting the male mating portion 3 7a into the female mating portion 37b, the latter is pressed in the thickness direction thereof.
In general, to facilitate transportation and assembly of a spinning machine, the frame body of the spinning machine is manufactured as a plurality of discrete frame units

each having a predetermined length. Subsequently, these frame units are transported to a customer"s spinning mill to be assembled into a spinning machine by combining the frame units together. To this end, the duct element portions of the duct assembly are formed in a length of about 2 meters to facilitate their transportation. In this case, seven or eight duct elements will be required to construct a duct assembly disposed at one side of a frame of a spinning machine having 200 spindles installed at each side. Nevertheless, the expenditure involved to transport the duct elements is high because of their large bulk. Under the circumstances, Japanese Patent Application Laid-open No. 9-53766 (JP-A-9-53766} proposes a box-like structure of a duct element for a spinning machine which is constituted by a plurality of planar component members of the same shape formed by cutting a blank sheet material in an appropriate size and shape so that the component members can be stacked onto one another to reduce the transportation cost.
As is well known in the art, a spinning machine frame is very long. Consequently, when the duct assembly for the spinning machine is manufactured in the form of a plurality of duct elements each of a certain length (about 2 meters) to facilitate the transportation thereof, a large number of duct elements have to be interconnected. When the method of interconnecting the duct elements by using coupling members interposed therebetween is adopted, in addition to the necessity to prepare the coupling members, the troublesome work of fitting the duct elements and the coupling members together is required. Consequently, the cost of installing

the duct assembly increases significantly.
On the other hand, the method of interconnecting the duct elements by forming each of the duct elements with a tapered structure and fitting the smaller diameter portion of one duct element into the larger diameter portion of an adjacent duct element can certainly facilitate the work of assembling the duct elements, provided that the individual duct elements are each formed with a uniform wall thickness. However, since each of the duct elements of the duct assembly are generally provided with the female mating portion 37b extending in the longitudinal direction, as previously mentioned herein (see Figs. 12 and 13), the wall thickness thereof is increased in the region of the female mating portion 37b. Consequently, fitting the smaller diameter portion of one duct element into the larger diameter portion of the adjacent one gives rise to a large force acting on the female mating portion 37b in a region where the duct elements are engaged with each other, which in turn gives rise to torsion in the duct elements. Even if the torsion in each duct element is of a small magnitude, it becomes very large in the duct assembly which is constituted by a large number of the duct elements. As a result, the portion of the flute 33 connected to the duct assembly 31 by way of the suction pipe 32 may deviate from a predetermined desired position. Moreover, with the method of interconnecting the duct elements by fitting the smaller diameter portion of a duct element into the larger diameter portion of an adjacent one, difficulty is encountered property in positioning the duct assembly properly in the longitudinal direction. More

specifically, when deviation in the longitudinal direction increases due to the interconnection of a large number of duct elements through the fitting procedure mentioned above, the position of the flute 33 coupled to the duct assembly 31 by way of the suction pipe 32 will be displaced from the predetermined desired position.
SUMMARY OF THE TNVEHTIOH
In light of the state of the art described above, it is an object of the present invention to provide a duct element with an improved structure which is suitable for constructing a duct assembly for a pneumatic clearer of a spinning machine by using a number of such duct elements, and which can facilitate the work or processes involved in interconnecting the duct elements while preventing torsion and longitudinal deviation in a duct assembly to such an extent that substantially no disturbance is brought about in the proper positioning of a flute or pneumatic nozzles.
In view of the above and other objects which will become apparent as the description proceeds, there is provided according to a general aspect of the present invention a duct element with a hollow box-like shape constituting a portion of a duct assembly for a spinning machine, wherein a plurality of the duct elements are interconnected by fitting a first end portion of a given duct element into a second end portion of another adjacent duct element to thereby constitute the duct assembly. The duct element includes a pair of component members corresponding to two halves of the box-like duct element. Each component

member is provided with mating portions at opposite sides with reference to a plane extending substantially through a center of the duct element and intersecting substantially orthogonally both ends of the duct element so that the component members can be joined air-tightly when used together, and positioning portions for regulating a length of a lap-joint portion, formed longitudinally when a first end portion of one duct element is fit into a second end portion of another duct element, to a predetermined amount.
With the structure described above, a duct element with a hollow box-like form is constructed by joining the two component members together by engaging the mating portions thereof so that they are airtight when the duct operates. Duct elements are interconnected by inserting a first end portion of one duct element into a second end portion of another duct element. The length of the lap-joint portion formed longitudinally between the interconnected duct elements is regulated to a predetermined amount by the positioning portions, when the duct elements are interconnected, since the mating portions are formed at opposite sides with reference to a plane extending substantially through the center of the duct element and intersecting substantially orthogonally both ends of the duct element, even if a force acts torsionally at each mating portion of a duct element, both duct elements cancel out each other"s torsion and hence torsion in the duct assembly is thereby prevented.
In a preferred mode of carrying out the invention, the mating portions may be formed symmetrically to each other

with reference to a plane which extends substantially through a center of the duct element and intersects substantially orthogonally both ends of the duct element.
By virtue of the structure described above, the duct elements and hence the duct assembly can be more reliably protected against torsion.
In another preferred mode of carrying out the invention, the duct element may be arranged so as to be divided into a first component member constituting a bottom wall and a second component member constituting an other wall or walls.
With the duct element structure described above, forming mating portions symmetrical with reference to the plane extending through a center of the duct element and intersecting orthogonally both ends thereof is facilitated, because the first component member constitutes the bottom wall of the duct element.
In yet another preferred mode of carrying out the invention, the mating portions of the first component member may be formed longitudinally at both sides of the first component member in the form of roughly U-shaped bent portions having grooves such that the mating portions of the second component member comprising bottom portions of the front and rear wall are insertable therein.
With the duct element structure described above, the lower end portions of the second component member are positioned opposite the mating portions of the first component member and the second member is assembled onto the first member from above.
In still another preferred mode of carrying out the

invention, both component members are joined together with both lower end portions of the second component member press-fit into the bent portions of the first component member.
Accordingly, the air-tightness of the mating portions or joints can be ensured without resorting to a bending or caulking process after assembling the first and second component members.
In a further preferred mode of carrying out the invention, the mating portions of the component members may be formed in shapes such that the component members can be joined together by moving one of the component members in a direction orthogonal to a longitudinal direction of the other component member.
Since, the first and second component members can be joined together fay simply moving one of the component members toward the other component member, the work of assembling the duct elements is facilitated.
In a yet further preferred mode of carrying out the invention, the positioning portions are formed by removing a portion of the mating portions corresponding to a lap-joint portion formed when the duct elements are interconnected.
Thus, the positioning portions can be easily formed. Further, because the end of one duct element contacts the positioning portion of the adjacent duct element when the duct element are connected, the longitudinal length of the lap-joint portion is limited to a predetermined amount.
In a still further preferred mode of carrying out the invention, at least the portion of one duct element that

is fit into the end portion of another duct element when the duct elements are interconnected to construct the duct assembly, is formed with a gradual taper in the downstream direction of the air flow.
Consequently, interconnection of the duct elements is facilitated and fleece or the like can be transported smoothly without being caught or trapped at the joint portions within the duct assembly.
Further, according to another aspect of the invention, there is provided a box-like duct assembly which is constituted by interconnecting a plurality of the duct elements described above.
Accordingly, the present invention provides a duct element of a hollow box-like shape constituting a part of a duct assembly for a spinning machine, wherein a plurality of said duct elements are interconnected by fitting a first end portion of one of said duct elements into a second end portion of another adjacent duct element to thereby construct said duct assembly, comprising; a pair of component members corresponding to two divisions of said box-like duct element, each of said component members being provided with mating portions respectively, at opposite sides with reference to a plane extending substantially through a center of said duct element and intersecting substantially orthogonally both ends of said duct element so that said component members are joined together fluid-tightly in the state of usage by engaging said mating portions with each other; and positioning portions for regulating to a predetermined amount a longitudinal length of a lap-joint portion formed when a first end portion of one of said duct elements is fit into a second end portion of another duct element upon assembly of said duct assembly.

The above and other objects, features and attendant advantages of the present invention will be more easily understood by reading the following description of the preferred embodiments thereof taken, only by way of example, in conjunction with the accompanying drawings.
BRIKF DESCRIPTTON OF THE DRfiWTNGS
In the course of the description which follows, reference is made to the drawings, in which:
Fig. 1 is a partially sectional perspective view showing a structure of a duct element according to a first embodiment of the invention;
Fig. 2 is a perspective view showing assembled duct elements of the invention;
Fig. 3(a) is a fragmentary front view showing duct elements in an interconnected state;
Fig. 3 (b) is a fragmentary bottom plan view showing

duct elements in an interconnected state;
Fig. 4 is a schematic diagram showing duct elements in an interconnected state;
Fig. 5 is a side elevational view of a duct element according to another embodiment of the present invention;
Fig. 6 is a side elevational view of a duct element according to yet another embodiment of the invention;
Fig. 7 is a side elevational view of a duct element according to still another embodiment of the invention;
Fig. 8 is a side elevational view of a duct element according to a further embodiment of the invention;
Fig. 9 is a side elevational view of a duct element according to yet a further embodiment of the invention;
Fig. 10 is a side elevational view of a duct element according to a still further embodiment of the invention;
Fig. 11(a) is a schematic view showing a connected state of duct elements according to another embodiment of the invention;
Fig. 11(b) is a schematic view showing a connected state of duct elements according to a further embodiment of the invention;
Fig. 12 is a fragmentary side elevational view showing a structure of a known pneumatic clearer; and
Fig. 13 is a side view showing a conventional duct element.
nKSCRIPTTON OF THE PREFERRFin FMB0DTMEHT5
The preferred embodiments of the present invention will now be described in detail with reference to the drawings .

In the following description, like reference characters designate like or corresponding parts. Also in the following description, it is to be understood that terms such as "left", "right", "top", ■•bottom", "front", "rear", "box-like", "diameter" and the like are words of convenience and are not to be construed as limiting terms. Embodiment 1
Now, referring to Figs. 1 to 4, description will be made of a first embodiment of the present invention. As is shown in Figs. 1 and 2, each duct element 1 is constituted by a pair of component members 2 and 3 in the form of a sleeve or hollow box of a substantially pentagonal cross-section.
Each of the component members 2 and 3 is formed by bending, for example, a metal sheet having a thickness of about 1 mm, wherein the first and second component members 2 and 3 are formed with shapes such that the duct element 1 is divided into two halves along a plane which extends to orthogonally intersect both ends thereof. The duct element 1 has a length of about 2 meters and is tapered such that the cross-sectional area thereof increases gradually from a first end (right end as viewed in Fig. 2) toward a second end (left end as viewed in Fig. 2). Thus, according the present embodiment, when a duct assembly constituted by assembling a plurality of duct elements is installed in a spinning machine, the first end of each above mentioned duct element is located at a downstream side of the air flow while the second end is located at a upstream side of the air flow. The difference between the diametrical size of the first and second ends of the duct element 1 substantially corresponds to the sum of the wall

thickness of the first component member 2 and the second component member 3. By way of example, if the duct element has a diametrical size, e.g. height of 200 mm at the first end (right end in Fig. 2), the diametrical size or height at the second end (left end in Fig. 2) would be about 202 mm as shown in Fig. 4.
The base member ( first component) 2 includes a plate portion 2a which constitutes a bottom wall of the duct element 1. A female bent portion 2b is formed along each longitudinal side of the plate portion 2a. More specifically, each female bent portion 2b is bent or folded so as to form a substantially U-like groove 2c for receiving a bottom edge portion of the hood-like member 3.
The hood-like member (second component) 3 is comprised of a front wall la, a suction-pipe mounting wall lb, a top wall Ic and a rear wall Id which are continuously formed by bending a metal sheet. More specifically, the front wall la and the rear wall Id extend in parallel with each other and have respective lower end portions which are formed so as to lie on a plane which extends substantially in parallel with the top wall Ic. The suction-pipe mounting wall lb is formed with through-holes 4 for mounting a suction pipe thereat (not shown). A number of such through-holes 4 of appropriate size may be provided depending on the type of pneumatic clearer to be employed, i.e., flute type or single nozzle type. That is, the duct element 1 can be employed in combination with a flute type pneumatic clearer or a single-nozzle type pneumatic clearer.
Referring to Fig. 1, the base member (first

component) 2 is provided with notches 5a and 5b at both ends thereof, respectively, which are formed by partially removing the material of the female bent portions 2b. The end faces of the female bent portion 2b resulting from formation of the notches 5a and 5b serve as positioning portions 6, respectively. A portion of the base plate 2a held between the notches 5b provided at the second end of the duct element 1 mentioned previously is formed so that the width thereof gradually decreases toward the second end. When the component members 2 and 3 are joined together, as shown in Fig. 2, front and rear lower end male portions 3a of the hbod-like member ( second component) 3 project outwardly from the female bent portions 2b, respectively, of the base member (first component) 2,
Next, the description will turn to assembly of the duct element 1 described above and assembly of a duct assembly. Upon assembling the duct element 1, the base member (first component) 2 and the hood-like member (second component) 3 are disposed so that both lower end male portions 3a of the hood-like member 3 are positioned opposite the grooves 2c of the base member 2, whereupon the hood-like member 3 is pressed downwardly from above. As a result, both the lower end male portions 3a of the hood-like member 3 are inserted into the grooves 2c, respectively, and the component members 2 and 3 are secured together.
On the other hand, to construct a duct assembly by interconnecting the duct elements 1 thus formed, the first end portion (reduced diameter portion) of one duct element 1 is inserted into the second end portion (larger diameter

portion) of another duct element 1. In this state, the front wall la, the suction-pipe mounting wall lb, the top wall Ic, the rear wall Id and the bottom wall of the one duct element 1 at the first end portion thereof are positioned inside the front wall la, the suction-pipe mounting wall lb, the top wall Ic, the rear wall Id and the bottom wall, respectively, of the other duct element 1, as csn be seen in Figs. 3(a) and 3(b).
Since the hood-like member (second component) 3 has no overlapping bent portion in the thickness direction thereof, the first end portion of the one duct element 1 can be fit into the second end portion of the other duct element 1 without any appreciable difficulty. On the other hand, the base member (first component) 2 has the female bent portions 2b overlapping in the thickness direction thereof. Consequently, if the female bent portions 2fa extend over the entire length of the second component member 2, the female bent portions 2b provide an obstacle to the insertion of the first end portion of the one duct element 1 into the second end portion of the other duct element 1. However, with the duct element 1 according to this, both of the duct elements 1 to be coupled together are provided with the notches 5a and 5b, respectively, at locations corresponding to the portions where the duct elements are connected to each other. Since the female bent portions 2b at these portions are deleted, when the duct elements 1 are interconnected by inserting the reduced diameter portion of one duct element 1 into the large diameter portion of another one, the female bent portions 2b of the base member 2 provide no obstacle.

Furthermore, both the lower end male portions 3a of the hood-like member (second component) 3 located at the first end (downstream side) of one duct element 1 bear against the positioning portions 6, respectively, which are formed at the second end {upstream side) of the base member {first component) 2 of the other duct element 1 upon insertion of the one duct element 1 into the other duct element 1, while both the lower end male portions 3a of the hood-like member 3 located at the second end of the one duct element 1 bear against the positioning portions 6, respectively, which are formed at the first end of the base member 2 of another duct element 1. In this way, the length of the lap-joint region or portion in the longitudinal direction of the interconnected duct elements 1 can be limited to a predetermined amount.
The structure of the duct element described above enjoys advantageous effects which will now be mentioned below.
(a) when a plurality of duct elements 1 are telescopically interconnected by inserting the reduced diameter portion of one duct element into the larger diameter portion of another duct element to thereby assemble a duct assembly after having assembled each tapered duct element by engaging the mating portions (lower end male portions 3a and female bent portions 2b) extending longitudinally along the two component members 2 and 3, respectively, the mating portions, overlapping in the direction of the thickness of the duct element 1, do not overlap each other. Consequently, since a force does not act torsionally on the duct element

1, torsion in the individual duct elements, and hence in the duct assembly, is prevented,
(b) Upon interconnection of the duct elements 1, the length of the lap-joint portion or region in the longitudinal direction of the duct element 1 can be limited to a predetermined amount due to the action of the positioning portions 6 provided at both ends of the duct element 1, and deviations in the longitudinal direction, of the interconnected duct elements, large enough to hinder the desired positioning of the flute or pneumatic nozzles are prevented.
(C) Assembly of the duct element 1 can be carried out very simply by merely fitting one mating portion (lower end male portion 3a) into the other (female bent portion 2b). Moreover, even when the thickness of the lower end male portion 3a is smaller than the width of the female groove 2c and there is a gap between the lower end male portion 3a and the female bent portions 2b, when the front wall la and the rear wall Id are pushed inwardly by application of a negative pressure to the duct assembly from a vacuum source ( not shown) , the lower end male portion 3a is caused to bear on the female bent portions 2b, and air-tightness can thereby be ensured. (d) When a plurality of duct elements 1 are connected by inserting the smaller end of one duct element 1 into the lager end of another duct element, the positioning portion 6 can be automatically formed by removing a predetermined length from the female bent portions 2b such that the mating portions, when combined, do not overlap each other in the direction of the thickness of the duct element 1.

(e) since the duct element 1 is constituted by the first component member 2 serving as the base member forming the bottom wall and the second component member 3 forming the other walls of the duct element, compared to the construction wherein mating portions are formed midway on front wall la and rear wall lb the inner wall surface of the duct element 1 can be formed flat, and it becomes difficult for fly waste and fibers to remain midway in the duct assembly. { f) Interconnection of the duct elements is facilitated due to their tapered structure.
{g) Since an end portion of the duct element 1 is formed with a taper that gradually decreases toward the downstream side of the duct assembly, when the duct elements are interconnected to construct the duct assembly, fleece or the like can be transported smoothly without being caught by or trapped at the joint portions within the duct assembly.
The present invention is not limited to the above mentioned embodiment, but may also embodied as described below. Embodiment 2
A second embodiment of the present invention will be described with reference to Fig. 5. According to the second embodiment, with the lower male portions 3a of the second component member not inserted, each female bent portion 2b formed integrally with the first component member {base member) 2 with a substantially U-shape in cross-section may be formed so that width gaps at top portions of the female bent portions 2b are smaller than the thicknesses of the lower end male portions 3a, and the lower end male portions 2a are

then press fit into the female bent portions 2b. In this case, with the lower end male portions inserted into the female portions 2b, the first component member (base member) 2 and the second component member (hood-like member) 3 can be positively joined together in an air-tight manner. Embodiment 3
As shown in Fig. 6, instead of the construction wherein the structure of the mating portions is such that the lower end male portions are inserted into the grooves 2c mating members 2d are foldedly formed at both sides of the first component member 2 as inward facing convex are surfaces. On the other hand, mating members 3b are formed at lower end surface portions of the second component member 3 so as to be engageable with the mating members 2d, respectively, of the first component member. Also according to the structure of this embodiment, portions of the mating members 2d, corresponding to the area where they overlap when the duct elements 1 are connected, are removed at both end portions of the first component member 2 . In this case, both the mating members 2d and 3b exhibit resiliency, and the first component member (base member) 2 and the second component member (hood-like member) 3 can be simply assembled by pressing the second component member (hood-like member) 3 onto the first component member (base member) 2 from above. Each of the mating members 2d and 3b may also be formed as outward facing convex arc surfaces, respectively, with substantially the same effect as the structure shown in Fig. 6. Embodiment 4
The mating portions are not necessarily restricted

to shapes which are symmetrical to each other with reference to a plane extending substantially through a center of the duct element 1 and intersecting substantially orthogonally both the ends of the duct element 1. That is mating portions of different types may be disposed at opposite sides with reference to a plane extending substantially through a center of the duct element and intersecting substantially orthogonally both the ends of the duct element. Figure 7 shows a structure of a duct element according to a fourth embodiment of the present invention. As can be seen in the figure, the first component member (base member) 2 is provided with a female bent portion 2b at a side corresponding to the front wall la, while a mating member 2d is formed at the opposite side corresponding to the rear wall Id that it presents an inward facing convex arc surface. On the other hand, a lower end male portion 3a is formed at the front wall la of the second component member (hood-like member) 3 and a mating member 3b is formed at a lower portion thereof in a complementarily arcuate shape so as to be engageable with the mating member 2d of the first component member (base member) . Also according to the structure of this embodiment, portions of the female bent portions 2b and the mating members 2d, corresponding to the areas where they overlap, respectively, when the duct elements 1 are connected, are removed at both end portions of the first component member 2 . The structure of the duct element according to the present embodiment obtains advantageous effects similar to those of the first embodiment. Embodiment 5

The mating portions need not necessarily be provided at both sides of the bottom wall. They may be provided at top and bottom sides of the duct element 1. For example, as can be seen in Fig. 8, a duct element 1 according to the instant embodiment is comprised of a first component member 10 and a second component member 11 which comprise the front wall la, the suction-pipe mounting wall lb, the top wall Ic and a bottom wall le. Bent portions 10b having grooves 10a for receiving mating members 11a of the second component member 11 are formed at top and bottom sides of the first component member 10. Also according to the structure of this embodiment, portions of the bent portions 10b formed at the first component member 10, corresponding to the area where they overlap when duct elements 1 are connected, are removed at both end portions of the first component member 10. The structure of the duct element according to the present embodiment obtains advantageous effects similar to those of the first embodiment. Embodiment 6
The present invention can find application not only to the duct assemblies installed at both lateral sides of a frame but also to the duct assembly to be installed longitudinally at the center of a frame. For example, figure 9 shows a duct element 1 which has a hexagonal cross-section. As can be seen in the figure, bent portions 7b having grooves 7a for receiving mating members 8a of a second component member 8 are formed at both top sides, respectively, of a first component member 7 at bottom, and mating members 8a at both bottom sides of the second component member 8 project

horizontally. According to the structure of this embodiment of the present invention, portions of the bent portions 7b of the first component member 7, corresponding to the area where they overlap when the duct elements are connected, are removed at both end portions of the first component member 7. In the present embodiment, the first component member 7 and the second component member 8 can fit inside each other, which allows these component members to be packaged efficiently. Consequently, the packaging and transportation costs can be advantageously reduced.
As a modification of the present embodiment, the mating members 8a provided at bottom sides of the second component member 8 may be formed so as to extend downwardly while the bent portions 7b of the first component member 7 may be formed so that the grooves 7a are oriented upwardly to receive therein the downwardly extending mating members 8a. Embodiment 7
Figure 10 shows a duct element according to a seventh embodiment of the present invention. The mating portions for joining the first and second component members together need not necessarily be disposed on the exterior of the duct elements. It is equally possible to provide the mating portions in the interior of the duct elements as shown in Fig. 10. More specifically, the lower end portions of the second component member 3 are bent inwardly to form bent male portions 3c, while female mating portion 9a are formed at both sides of a first component member 9. In this case, the female mating portions 9a are not notched, the duct elements are

connected in the state where the mating portions overlap each other. Consequently, when a plurality of tapered duct elements are interconnected for realizing a duct assembly, a force may act to bring about torsion in the individual duct elements at the locations where the mating portions or joints overlap each other in the thickness direction thereof. However, since the mating portions or joints are formed symmetrically to each other with reference to a plane extending substantially through a center of the duct element and orthogonally intersecting both end faces of the duct element, the forces acting on the duct elements are mutually canceled out, whereby torsion in the duct elements, and hence the duct assembly, can be prevented. With the structure of the duct element according to this embodiment of the present invention, it is necessary to provide the positioning ineans for limiting the longitudinal length of the lap-joint portion formed upon interconnection of the duct elements separately. As such positioning means, for example, a stopper member may be formed on an external surface of the duct element in the vicinity of the smaller diameter end of the duct element.
Many features and advantages of the present invention are apparent from the detailed description and thus it is intended by the appended claims to cover all such features and advantages which fall within the true spirit and scope of the invention. Further, since numerous modifications and combinations will readily occur to those skilled in the art, it is not intended to limit the invention to the exact construction and operation described.
By way of example, the duct element 1 of the present

invention is not restricted to any particular shape or geometrical configuration. What is essentially required is that the duct element be of a hollow-box or sleeve-like form and that the duct elements can be interconnected by inserting a first end portion of a given duct element into a second end portion of another duct element to construct a duct assembly.
Thus, it is not necessarily required that the duct element be tapered so that the cross-sectional area thereof increases gradually from the first end toward the second end thereof so long as the requirements mentioned above can be satisfied.
By way of example, the duct element may be tapered at both end portions thereof with an intermediate portion having a constant cross-sectional area, as illustrated in Fig. 11 (a) .
Alternatively, the intermediate portion of the duct element may be tapered with both end portions thereof being formed with constant cross-sectional areas, as illustrated in Fig. 11(b). Needless to say, the length of the duct element 1 may be shorter or longer than two meters. Application of the present invention is not limited to the duct elements and duct assembly for a ring spinning machine. The teachings of the present invention may be equally applied to duct assemblies for flyer frames and other types of spinning frames.
Furthermore, in the structure of the duct element shown in Fig. 6, the mating members 2d and the mating members 3b may be formed so as to exhibit a spring action, and the duct element can be realized by simply pressing the second component member onto the first component member from above.
Accordingly, all suitable modifications and equivalents may be resorted to, falling within the spirit and

scope of the invention.

WE CLAIM:
1. A duct element of a hollow box-like shape constituting a part of a duct assembly for a spinning machine, wherein a plurality of said duct elements are interconnected by fitting a first end portion of one of said duct elements into a second end portion of another adjacent duct element to thereby construct said duct assembly, comprising:
a pair of component members (2, 3) corresponding to two divisions of said box-like duct element, each of said component members (2, 3] being provided with mating portions (2b, 3a) respectively, at opposite sides with reference to a plane extending substantially through a center of said duct element and intersecting substantially orthogonally both ends of said duct element so that said component members are joined together fluid-tightly in the state of usage by engaging said mating portions (2a, 3b) with each other; and
positioning portions (6) for regulating to a predetermined amount a longitudinal length of a lap-joint portion formed when a first end portion of one of said duct elements is fit into a second end portion of another duct element upon assembly of said duct assembly.
2. The duct element for a spinning machine according to claim 1,
wherein said mating portions (2b, 3a) are formed symmetrically to each other with reference to a plane which extends substantially through a center of said duct element (1) and intersects substantially orthogonally both ends of

said duct element (1).
3. The duct element for a spinning machine according to
claim 1,
wherein said duct element (1) is divided into a first component member (2) constituting a bottom wall and a second component member (3) constituting other walls*
4. "The duct element for a spinning machine according to
claim 3,
wherein the mating portions of said first component member (2) are formed longitudinally at both sides of said first component member (1) in the form of U-shaped bent portions (2b) having grooves (2c), respectively, and
wherein the mating portions of said second component member (3) are constituted by lower end portions (3a) of a front wall (la) and a rear wall (Id), respectively, which are insertable in said grooves (2c) of said U-shaped bent portions (2b) of said first component member (2).
5. The duct element for a spinning machine according to
claim 4,
wherein both component members (2, 3) are joined together to form a duct element {1) in a state where both lower end portions (3a) of said second component member (3) are press-fit into said bent portions (2b) of said first component manner (2), respectively.

6. The duct element for a spinning machine according to
claim 1,
wherein said mating portions (2b, 3a) of said component members (2, 3) are formed in shapes such that both of said component members (2, 3) may be joined together by moving one of said component members relative to the other in a direction orthogonal to a longitudinal direction of said component members (2, 3).
7. The duct element for a spinning machine according to
any one of the preceding claims,
wherein said positioning portions (6) are formed with portions of said mating portions that correspond to lap-joint portions, formed when one duct element (1) is telescopically inserted into an other duct element to form a duct assembly, removed.
8. The duct element for a spinning machine according to
any one of the preceding claims,
wherein said duct element (1) is longitudinally tapered so that said duct element (1) has a reduced diameter end portion and a larger diameter end portion, and
wherein said duct assembly is constituted by inserting telescopically said reduced diameter portion Qf one duct element into said larger diameter portion of another duct element, said reduced diameter end portions of said duct elements being positioned downstream of a fluid flow of said duct assembly.

9. A duct assembly of a hollow box-like form for a spinning machine
constituted by interconnecting a plurality of duct elements (1) as
claimed in any one of claims I to 8.
10. A duct element substantially as herein described with reference to
figures 1 to lib of the accompanying drawings.

Documents:

1357-mas-1998 abstract duplicate.pdf

1357-mas-1998 abstract.pdf

1357-mas-1998 claims duplicate.pdf

1357-mas-1998 claims.pdf

1357-mas-1998 correspondence-others.pdf

1357-mas-1998 correspondence-po.pdf

1357-mas-1998 description (complete) duplicate.pdf

1357-mas-1998 description (complete).pdf

1357-mas-1998 drawings duplicate.pdf

1357-mas-1998 drawings.pdf

1357-mas-1998 form-13.pdf

1357-mas-1998 form-19.pdf

1357-mas-1998 form-2.pdf

1357-mas-1998 form-26.pdf

1357-mas-1998 form-4.pdf

1357-mas-1998 form-6.pdf

1357-mas-1998 others.pdf

1357-mas-1998 petition.pdf

« Previous Patent

Next Patent »

Patent Number

196419

Indian Patent Application Number

1357/MAS/1998

PG Journal Number

08/2007

Publication Date

23-Feb-2007

Grant Date

17-Feb-2006

Date of Filing

19-Jun-1998

Name of Patentee

M/S. KABUSHIKI KAISHA TOYOTA JIDOSHOKKI

Applicant Address

1, TOYODA-CHO, 2-CHOME, KARIYA-SHI, AICHI-KEN,

Inventors:

#	Inventor's Name	Inventor's Address
1	MAKOTO YAKUSHI	C/O KABUSHIKI KAISHA TOYODA JIDOSHOKKI SEISAKUSHO, 1, TOYODA-CHO 2-CHOME, KARIYA-SHI, AICHI-KEN,
2	HISSAKI HAYASHI	C/O KABUSHIKI KAISHA TOYODA JIDOSHOKKI SEISAKUSHO, 1, TOYODA-CHO 2-CHOME, KARIYA-SHI, AICHI-KEN,

PCT International Classification Number

D01H 11/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	9-164420	1997-06-20	Japan