Dye spring
BACKGROUND OF THE INVENTION 
     This invention is directed towards improvements in collapsible dye tubes, commonly referred to as dye springs. The dye springs of the present invention are characterized in that they are resiliently compressible and are further able to withstand elongation. The dye spring has a surface area of cylindrical shape with elements disposed between rings at the end of the tube. The elements insure that the dye spring surface area remains open when the dye spring is in a compressed state so that dye will be able to flow radially outwardly through the tube and thereby dye the yarn wound around the tube. The elements further insure that the degree of elongation and/or compression experienced by the spring during winding operations is substantially diminished or even eliminated. 
     THE PRIOR ART 
     Generally, dye springs are made of a molded thermoplastic material that is collapsible and are disposable after a single use. The dye tube is wound with yarn and the yarn dyed. The yarn thereafter is wound off the tube and the tube is discarded. The dye tube of prior art U.S. Pat. No. 4,181,274 comprises a pair of annular flanges and an intermediate structure between the flanges comprising at least one member extending generally axially to the length of the tube and a plurality of rigid members, such as rings or helices, that extend generally transversely to the length of the tube. The members are integrally formed by molding to initially define a rigid structure having an open network with at least some of these rigidly extending members being deformable by an axial force to cause axial compression of the tube. These members are referred to as ribs which form an open network to permit passage of dye therethrough. 
     Prior art U.S. Pat. No. 3,465,984 discloses a carrier resiliently compressible in the axial direction which comprises end rings and at least one intermediate ring with a plurality of ribs disposed between the end rings. These ribs are elastically bendable and equally distributed along the periphery of the carrier and inclined for at least a part of their length to the longitudinal axis of the carrier. The outer edges of the ribs are oriented toward the surface of the carrier, the ribs being rigidly secured to the rings. 
     The prior art attempts to insure that the cylindrical surface of the dye spring remains sufficiently open after compression have not been entirely successful. Frequently the members deform so that the surface of the dye tubes become closed, effectively limiting, if not prohibiting, dye flow. Furthermore, the prior art does not adequately address the phenomenon of spring elongation and/or compression, which is caused by the torsional forces applied to the spring during winding operations. Elongation is highly adverse because it causes the springs to buckle and possibly jump out of the winding machines or prevent machines from automatically doffing. Compression usually causes the spring to jump out of the machine. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an improved dye spring which is open on at least part of its surface when it is compressed. 
     It is a further object of the invention to provide an improved dye spring which resists and withstands elongation and/or compression during the winding operation. 
     Other objects shall become apparent from the following disclosure. 
     The present invention is directed towards a dye spring that is resiliently compressible in the axial direction and is able to prohibit or prevent elongation and/or compression in the axial direction. The dye spring generally has a surface area of cylindrical shape with elements disposed between rings at the end of the tube. The elements are generally comprised of at least one ring member, and a plurality of spaced, rigid stays that are integrally formed with the rings and define therewith an initially rigid network for winding yarn which is to be dyed. The elements are generally comprised of a structure of outer members and inner members appearing upon and integral with the outer members. The outer members are integral with the rings and define an area in the spaces between the rings. The inner members are integral with the outer members and lie in the circumferential plane formed by the rings of dye spring. The network of outer members and inner members cooperate to insure that a portion of the circumferential surface of the dye spring remains open upon compression of the tube so that dye can flow radially outwardly through the open spacing. Also provided are axial spacing stops that are integral with the rings and formed in pairs. Each member of the pair sits adjacent to the other member of the pair with the pairs being aligned so that each pair is substantially parallel along an axis formed along the length of the tube. The network of outer and inner members further cooperate to substantially diminish or prevent the dye spring from elongating and/or compressing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1a is a partial side elevational view of a first embodiment of the present invention. 
     FIG. 1b is a partial side elevational view of the embodiment of FIG. 1a shown in a compressed state. 
     FIG. 1c is partial side elevational view of a second embodiment of the present invention in a compressed state. 
     FIG. 1d is a partial side elevational view of an alternative to the first embodiment shown in FIG. 1b. 
     FIG. 1e is a partial side elevational view of a third embodiment of the invention. 
     FIG. 1f is a partial side elevational view of the third embodiment of the invention in a compressed state. 
     FIG. 2a is a partial side elevational view of a fourth embodiment of the present invention. 
     FIG. 2b is a partial side elevational view of the embodiment of FIG. 2a shown in a compressed state. 
     FIG. 3 is a partial side elevational view of a dye spring incorporating the first embodiment of the present invention. 
     FIG. 4 is a partial side elevational view of the dye spring of FIG. 3 in the compressed state. 
     FIG. 5 is a partial side elevational view of a dye spring incorporating the fourth embodiment of the present invention. 
     FIG. 6 is a partial side elevational view of the dye spring of FIG. 5 in the compressed state. 
     FIG. 7 is a partial side elevational view of a section of the dye spring under a tensile load. 
     FIG. 8 is a partial side elevational view of a section of the dye spring under a compressional load. 
     FIG. 9 is a top perspective view of the dye spring. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The figures depict a dye spring constructed in accordance with the principles of the present invention. The dye spring structure and dye spring itself is shown in FIGS. 1a, 2a, 3 and 5. End rings 25 define the outer edge of the tube, with the rings 5 being spaced intermediate the end rings 25. Rings 5 and end rings 25 define a cylindrical surface area along the longitudinal axis of the spring, with the length of that axis itself L30 defined by the spacing of the rings 5 and end rings 25, and the number of rings 5. 
     Outer members 10 are integrally formed with rings 5 and 25 and in combination with rings 5 and 25 define a cylindrical open surface area along the spring. Outer members 10 may be circular in shape, as is shown in FIG. 1a and 3, or it may have the shape of a square, rectangle, or other parallelogram as shown in FIGS. 2a and 5. Inner members 8a, 8b are integrally formed upon the outer members 10. Outer member 10, as well as inner members 8a, 8b lie in the circumferential plane P formed within the circumferential surface area of the dye spring. See FIG. 9. Inner members 8a, 8b have a length dimension L (see FIG. 2a) so that they nearly abut each other when the spring is in the uncollapsed and unelongated state. Inner members 8a and 8b are connected by bridge 8c which is integral with inner members 8a and 8b. Bridge 8c is relatively thinner than members 8a and 8b and will elongate upon compression of the dye spring. See FIG. 1b. Alternatively, bridge 8c can be designed to fracture upon compression. See FIGS. 1c, 1d.  Under either alternative, bridge 8c provides resistance which inhibits the occurrence of total dye spring collapse. 
     The rings can be additionally provided with axial spacing stops 15 integral with the rings 5, which extend into the space between the rings, grouped together in pairs parallel to the longitudinal axis of the tube. Axial spacing stops 15 are dimensioned so that upon compression of the tube the pairs of stops will not abut each other so that yarn pinching, an adverse condition, will be avoided. The dye springs of the present invention are designed so as to collapse axially when a predetermined force is applied to the tube. The predetermined force will generally be an amount required to collapse the dye spring after the winding the yarn upon the tube. 
     When the dye spring is collapsed, the network of outer members and inner members function to insure that a portion of the cylindrical surface area of the dye spring remains open during and after collapse of the dye spring so that dye can flow through the spaces in the cylindrical area upon the dye spring and contact the yarn wound upon the spring. The dye spring is shown in a collapsed position in FIGS. 1b, 1c, 1d, 1f, 2b, 4 and 6. 
     During collapse, the dye spring becomes compressed, forcing the rings closer together, compressing the outer members 10 so that they become elongated in shape. As shown in FIGS. 1b, 4, and 8, the circular outer members become elongated and take on an oval shape. A similar effect can be observed for the parallelogram shaped outer members in FIGS. 2b and 6. The inner members 8a,  8b, which are integral with the outer members 10, move outwardly and away from each other thus stretching or fracturing the bridge 8c as shown in FIGS. 1b and 8 when a compression force C is applied to the dye spring. Referring to FIGS. 1b and 2b, the movement of the inner members 8a, 8b due to the elongation of the outer members 10 stretches bridge 8c. Bridge 8c may also fracture due to the elongating effect. In any event, the stretching of bridge 8c resists the compressive forces that may develop during winding. The combination of adjacent outer members or outer member and adjacent stops prevent the total collapse of the dye spring which would effectively prohibit or reduce the flow of dye radially outwardly through the tube. 
     An additional manner of preventing total collapse is to space adjacent outer members so that upon collapse, the elongated outer members will abut each other and thereby provide an additional source of resistance to total collapse. See FIG. 1c. This embodiment can be provided for by omitting axial spacing stops 15. 
     The inner and outer members also prevent or at least substantially diminish the degree of elongation experienced by the dye spring during the winding operation. Elongation is the result of torsional forces exerted on the spring during the winding operation and could result in buckling of the dye spring or cause the dye spring to jump out of the winding mandrel. As illustrated in FIG. 7 tensile forces are exerted upon the dye spring 30, urging the dye spring to elongate as designated by arrows T. As a result of this urging the opposite sides of the outer members 11, 12 will tend to move closer together as shown by the arrows A and A&#34;. Because the inner members 8a, 8b are joined by bridge 8c and are dimensioned to abut each other upon elongation of the spring, the abutting action of the inner members 8a, 8b and compression of bridge 8c will further prohibit the outer members from moving closer together, stabilizing the spring against further elongation. It should be apparent to a person skilled in the art that while it is not necessary for the inner members to abut each other, they should be of a sufficient length so that they will be caused to abut during the application of a torsional force and prohibit an undesired degree of elongation. 
     An alternative embodiment is shown in FIG. 1e, wherein only one inner member is provided with a bridge 8c. This embodiment would also function to prevent compression and elongation in the manner set forth for the embodiment having inner members 8a and 8b. FIG. 1f shows this embodiment in a compressed state, where bridge 8c has been fractured. 
     The dye springs of the present invention are preferably integral and injection molded from polypropylene and similar thermoplastic resins and modifications thereof. The material used should be able to withstand the elevated temperatures of dye baths and should provide sufficient structural integrity to endure the various forces described above and other forces apparent to the skilled artisan.