Patent Publication Number: US-6663032-B2

Title: Multi-segment roll package

Description:
This is a divisional of application Ser. No. 09/843,012, filed Apr. 26, 2001, now U.S. Pat. No. 6,595,448. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to winding and, more particularly, to winding tape on cores to build roll packages of tape. 
     Tape, especially plastic tape, has become commonplace in a number of products including electrical products such as wire, cable, conduit, transformers and other electrical components, general purpose tapes and packaging. The use of plastic tape as ties in plastic garbage and storage bags has grown significantly. Manufacturers utilize plastic tape in the form of rolls in automated machinery to produce a wide range of such products. 
     Rolls of plastic tape are normally wound on cores to aid in winding and provide improved stability of the roll. They are sometimes wound as a single “pancake” package which comprises a single roll having a width equal to the width of the plastic tape or film. Such a roll has the disadvantage of becoming unstable at large roll outer diameters, especially if the tape is narrow. The single roll package also limits the length of plastic tape, requiring frequent stopping of the machinery for roll changes. 
     Another winding method for roll packages utilizes a spool package that employs a continuous helical winding that alternates in direction similar to winding a reel of fishing line or string. This method produces a roll package with a width greater than the tape width and provides additional capacity of the roll package as compared to the “pancake” roll package. This method results in a condition of “soft” ends resulting from voids between the windings at the roll ends caused by the helical pattern. This winding method suffers the disadvantage of instability, and limits the diameter to which the roll package may be wound. Use of spools with end discs improves the stability, but increases the complexity, cost and weight of the package. 
     U.S. Pat. No. 4,568,033 discloses a tape package comprising a winding method which incorporates a flanged portion and a central helical traverse portion. The wind portions are built up from a plurality of windings to form steps. The height of the step is limited by the ability of the tape to traverse the steps. U.S. application Ser. No. 09/370,677 hereby incorporated by reference, discloses a multi-segment roll package that utilizes a novel pattern of end, center and intermediate roll segments made up of winding groups separated by helical transition windings. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     Therefore, an object of the present invention is to provide a roll package having a high wrapping density, increasing the length of tape in a given package outer diameter. 
     A further object of the present invention is to provide a roll package that may be wrapped to larger roll diameters, increasing the capacity of the roll package. 
     A further object of the present invention is to provide a roll package with improved mechanical stability, reducing the reject rate of roll packages due to damage. 
     Yet another object of the present invention is to provide a roll package that combines the advantages of the simple spooled roll package and the high-density multi-segment roll packages of earlier designs. 
     The roll package of the present invention includes a continuous length of tape wrapped as a conventional spooled roll segment sandwiched between two outer or end roll segments. The end roll segments and the spooled roll segment are wrapped on a common core and share a common winding axis. The end roll segments are built up from spiral winding groups of one or more zero-pitch spiral windings interrupted or separated by helical transition windings which transition to and from the spooled roll segment. The helical pitch of the transition windings is greater than the helical pitch of the spooled roll segment. The spooled roll segment is built up from layers of helical spool windings of a predetermined pitch. In the preferred embodiments, the spooled roll segment is at least two tape widths wide. The end segments are substantially one tape width wide. 
     In the preferred embodiments, the helical pitch of the transition windings is greater than the tape width. A high transition winding pitch, greater than the spool pitch of the center spooled roll segment, aids in transitioning the “step” or difference in height created during the build-up of the segments. The high transition winding pitch reduces humps or distortions that would otherwise result. 
     In the preferred embodiments, the roll package is made by wrapping one or more spiral windings at the first end segment position, wrapping a helical transition winding to the beginning of the spooled roll segment, wrapping a layer of helical spool windings at a spool pitch to the end of the spool roll segment position, wrapping a helical transition winding to the second end segment position and wrapping one or more spiral windings at the second end segment position. The axial direction of the windings is then reversed and the wrappings of spooled and end windings are repeated to the first end in a similar manner. The process is repeated until the roll package is wrapped to the desired diameter. 
     A second embodiment of the roll package incorporates one or more intermediate roll segments disposed between the spooled roll segment and the end segments. The intermediate roll segment is similar to the end roll segment except that the relative number of spiral windings in each winding group is approximately one half of the end roll segments. Helical transition windings connect the intermediate winding groups to the end winding groups and the spooled winding layers. 
     Yet another embodiment of the roll package incorporates an end spool portion made up of a plurality of wrappings with an end pitch different than spool pitch  211 . 
     The high-pitch helical transition windings act as connectors between the end roll segments and the spooled roll segment or the end roll segments, intermediate roll segments and spooled segments. The combined structure results in a package which eliminates the “soft end” problems of a conventional spooled roll package and allows larger diameter packages than would be practical with conventional spooled packages. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims and accompanying drawings where: 
     FIG. 1 is a perspective drawing of a multi-segment roll package having two end roll segments made up of spiral winding groups and a spooled roll segment made up of helically wrapped layers; 
     FIG. 1A is a detail end view of one end roll segment showing spiral windings making up the spiral winding groups, the spiral winding groups separated by helical transition windings; 
     FIG. 1B is a detail end view of the spooled roll segment showing spooled winding layers making up the spooled roll segment; 
     FIG. 2 is a partial cross section of the roll package taken along lines  2 — 2  of FIG. 1 showing the hump on the outside roll segments caused by the helical transition windings and the overlap of windings on the spooled roll segment; 
     FIG. 3 is a perspective drawing of an embodiment of the roll package of the present invention comprising two intermediate roll segments comprising spiral winding groups in addition to the end roll segments and spooled roll segment of the embodiment shown in FIG. 1; 
     FIG. 3A is a detail end view of the end roll segment showing the end spiral winding groups similar to those of FIG. 1A; and 
     FIG. 3B is a detail end view of the intermediate roll segment showing the intermediate spiral winding groups defined by spiral windings separated by helical transition windings. 
     FIG. 4 is a partial cross section of an alternative embodiment of the roll package having an end spool portion with a no-zero helical pitch less than the spool pitch of the center portion, and another embodiment having an end spool portion having three or more winding direction reversals between subsequent layers of the center spooled portion. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following is a description of the preferred embodiments of a multi-segment roll package of a continuous length tape and a method for making the package. 
     FIG. 1 is a perspective drawing of embodiment  101  of a multi-segment roll package comprising a continuous length of plastic tape  103  wrapped on core  105 . Package  101  is made up of end roll segments  107 A and  107 B, and spooled roll segment  109  disposed between roll segments  107 A and  107 B. End roll segments  107 A and  107 B and spooled roll segment  109  comprise a common longitudinal roll segment axis  111 . 
     End roll segments  107 A and  107 B are made up of a plurality of end spiral winding groups  108 , shown in detail FIG.  1 A. Each end winding group consists of at least one spiral winding such as windings  113  separated by helical transition windings  115 . Spiral windings  113  are wrapped spirally about roll axis  111  and, in the preferred embodiments, have substantially no (zero) helical pitch associated with them. For the purpose of this disclosure, helical pitch is defined as the axial length  116  the tape is displaced per revolution of the winding. 
     The helical transition windings have a significant helical pitch associated with the windings in order to transition to the adjacent segment, increase the stability of the package structure and to reduce humps or distortions between the roll segments as discussed later in this specification. 
     Spooled roll segment  109  comprises a substantially constant helical pitch to produce a plurality of consecutive helical spool windings  109 A,  109 B,  109 C which are axially displaced from each other by an amount depending on the magnitude of the helical spool pitch. 
     In the preferred embodiments, spooled roll segment  109  is a conventional spooled portion built up from a plurality of helical spool windings such as windings  109 A,  109 B,  109 C of FIG.  1 . Resulting layers  110  of spool windings are shown in FIG.  1 B. In the preferred embodiments, the helical pitch of the spool windings is less than the pitch of the helical transition portions, and in the preferred embodiments, the pitch of the spool windings is less than tape width  117 , resulting in overlapped spooled segment windings shown in FIG.  1  and FIG.  2 . 
     FIG. 2 is a partial cross section of the roll package taken along lines  2 — 2  of FIG.  1 . Building the roll package of FIG.  1  and FIG. 2 starts with wrapping at least one spiral winding at a starting point on core  105  such as the end segment  107 A position. Core  105  is rotated in direction  121  of FIG. 1 by a winding machine to wind a predetermined number of spiral windings  113  in radial direction  114 . A tape guide means, such as a tape guide of a winding machine then axially positions tape  103  during rotation of core  105  to transition tape  103  to the beginning of spooled roll segment  109  position to produce a helical transition winding such as winding  115 A of FIG.  1 . The term tape guide in this specification includes any means of changing the relative axial position of the tape to the roll package, such as the tape guide means of the winding machine disclosed in U.S. Pat. No. 6,007,016, hereby incorporated as a reference. The relative axial positioning rate or speed of the tape guide to the rotational speed of the winding machine defines a helical transition winding pitch of the winding. 
     The tape guide continues the axial positioning at the helical transition winding pitch until the outside (trailing) edge of tape  103  transitions to the beginning of spooled roll segment  109  position ( 203 A of FIG.  2 ). This position is defined by the tape width  117  plus the segment spacing  205 . In the preferred embodiments, segment spacing  205  is less than 0.5 times tape width  117 , and in the more preferred embodiments, spacing  205  is less than 0.25 times tape width  117 . In the most preferred embodiments, spacing  205  is 0.05 to 0.2 times tape width  117 . 
     The tape guide then begins a spool winding layer ( 110  of FIG. 1B) by axially positioning tape  103  at a second rate relative to rotational speed of the winding machine to define a spool winding pitch. The tape guide continues the spool transition at the spool winding pitch until the leading edge of tape  103  reaches the end of spooled roll segment  109  (position  203 B of FIG.  2 ). The tape guide then increases the pitch to the helical transition winding pitch until the leading edge of tape  103  reaches the outside of end segment  107 B position ( 207 B of FIG.  2 ). The tape guide holds this position, wrapping at least one winding or turn at end roll segment  107 B before reversing direction. In the preferred embodiments, the segment spacing between spooled roll segment  109  and end roll segment  107 B is the same as segment spacing  205 . 
     In the preferred embodiments, the tape guide transitions or guides tape  103  back to spooled roll segment  109  in the reversed direction at the helical transition winding pitch until the trailing edge of tape  103  reaches the end of spooled segment  109  (position  203 B), upon which time the tape guide slows to the spool winding pitch until the leading edge of tape  103  reaches spooled roll segment  203 A position. The tape guide then speeds to the helical winding transition pitch until the leading edge of tape  103  reaches end  207 A of end segment  107 A. The tape guide remains stationary to wind at least one winding at end roll segment  107 A position and the process repeats as described. 
     In the preferred embodiments, the helical transition pitch is greater than 0.5 times the tape width  117 , in the more preferred embodiments the helical pitch of the helical transition windings is greater than 1.0 times the tape width, and in the most preferred embodiments, the helical pitch of the helical transition windings is greater than 1.5 or 2.0 times the tape width. For tapes of reduced thickness, or of high elasticity, the helical transition winding pitch may be greater than 3, 4, or 6 times the tape width. The helical transition windings form connection “bridges”  210  directly between end roll segments and spooled roll segment  109 . These bridges add stability to the roll segments and allow larger diameter roll packages. 
     A relatively high helical pitch during the helical transition winding portion of the wrapping is important for several reasons. First, the axial transition from the end roll segments to the spooled roll segment means that more tape is wound on the inside of the end roll segments relative to the outside of the end roll segments. This difference in tape building results in a rise or hump  209 A on the inside of the end roll segment. It is desirable to reduce the magnitude of hump  209 A by increasing the pitch of the helical transition winding to reduce the added tape on the inside of the end roll segments. Also, the tape has a tendency to follow the “convex” portion of the roll package formed by hump  209 A, and increasing the helical pitch of the helical transition winding allows the guide to force the tape over the distortion of hump  209 A to the desired position. 
     In the preferred embodiments, spool pitch (shown by  211  of FIG. 2) of spooled roll segment  109  is less than the tape width resulting in overlap of the windings. In the more preferred embodiments, the helical pitch of the spool windings is less than 0.5 times the tape width, and in the more preferred embodiments, the helical pitch of the spool windings is between 0.2 to 0.5 times the tape width. In still other embodiments, the helical pitch of the spool windings is less than 0.2 or less than 0.1 times the tape width. The spool pitch  211  is adjusted depending on the number of spiral windings of the end roll segments in order to produce a generally cylindrical roll package without excessive concave or convex shape to the package. 
     In a variation of this embodiment, two or more layers  110  of helical windings may be applied to the spooled roll segment before transitioning to an end roll segment. The spool pitch and number of spiral windings in the end spiral winding groups  108  may be adjusted to provide the desired package shape. 
     FIG. 3 is a perspective drawing of embodiment  301  of a roll package employing two end roll segments,  107 A and  107 B, two intermediate roll segments  303 A and  303 B, and a spooled roll segment  109 . End roll segments  107 A and  107 B and spooled roll segment  109  are similar to those in the embodiments of FIG.  1  and FIG.  2 . 
     Intermediate roll segments  301 A and  301 B are made up of spiral windings  113  separated by helical transition windings  115  to form intermediate spiral winding groups ( 303  of FIG. 3B) similar to end spiral winding groups  108  of end roll segments  107 A and  107 B. In the preferred embodiments, intermediate spiral winding groups comprise approximately half the number of windings as end spiral winding groups  108  since the intermediate roll segments are “visited” twice each time the end roll segments are visited. The spacing between the end roll segments and the intermediate roll segments is similar to spacing  205  of FIG.  2 . 
     The addition of intermediate roll segments  303 A and  303 B improves the end stability of the package. In the preferred embodiments, the roll package is built up by winding the first end spiral winding group at position  107 A, winding a helical transition winding  115  to intermediate roll segment  303 A position and winding one half the number of spiral windings  113  as the end spiral winding group, winding a helical transition winding  115  to spooled roll segment  109  position, winding a layer of helical spool windings at the spool pitch to the end of the spooled roll segment, winding a helical transition winding  115  to intermediate roll segment  303 B position and winding an intermediate spiral winding group, winding a helical transition winding  115  to end segment position  107 B and winding an end spiral group. At this point, the tape guide would reverse and the process repeated. The spool pitch of the spooled roll segment windings may be adjusted to provide the desired package shape. 
     In a variation of this embodiment, two or more layers or “visits” of helical windings may be applied to the spooled roll segment before transitioning to an intermediate roll segment. The spool pitch and number of spiral windings in the intermediate spiral winding groups  303  may be adjusted to provide the desired package shape. Likewise, the number of visits of the intermediate roll segments may be varied in relation to the number of end roll segment visits from the normal ratio of 2 as disclosed in U.S. application Ser. No. 09/370,677, hereby incorporated by reference. The relative number of windings in the intermediate winding groups and the end winding groups may be adjusted to maintain the desired roll shape. 
     Still other embodiments of the modified spool roll are shown in FIG.  4 . The end treatment of embodiment  400 A utilizes an end spool portion  401  made up of a plurality of wrappings with an end pitch  403  less than spool pitch  211 . End portion  401  has a width greater than tape width  117  of FIG.  1 . In the preferred embodiments, end portion  401  is at least two tape widths and end pitch  403  is less than tape width  117 . In the more preferred embodiments, end pitch  403  is less than 0.75 times tape width  117 . In the still more preferred embodiments, end pitch  403  is less than 0.5 times tape width  117 . 
     The end treatment of embodiment  400 B utilizes an end pitch  407  equal to, or greater than, spool pitch  211 . The tape guide may be reversed two or more times within end portion  405  to produce more wrapped layers with a reversed helical pitch in end portion  405  as compared to center spooled portion  109 . This is shown schematically at end  400 B as end spool pitch reversals  409 B and  409 C after the pitch reversal  409 A which normally occurs in a spooled portion. 
     Accordingly the reader will see that the MULTI-SEGMENT ROLL PACKAGE FOR PLASTIC TAPE disclosed and claimed provides an improved roll package for plastic tape. The roll package provides the following additional advantages: 
     The roll package density is high, increasing the length of tape on a given size roll package as compared to conventional spooled roll packages, reducing converting roll change time and shipping costs; 
     The end roll segments increase the stability and decrease the softness of the package ends as compared to conventional spooled roll packages; 
     The roll package is stable, reducing roll package damage and waste; 
     Larger package diameters may be wound, reducing converting equipment change time and shipping costs; and 
     The roll package is simple to make and use. 
     Although the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. For example, in some embodiments, all of the winding groups meet the relative winding number specifications in this disclosure. In other embodiments, the majority, or at least a substantial number of, the winding groups meet the relative winding number specifications. In other embodiments, one or more helically-wound “wrapping layers” are wound over all of the roll segments to provide a protection and a stabilizing cover for the roll package. In still other embodiments, core  105  is a temporary core used for the wrapping process only. 
     The process may be used for tapes other than plastic, such as paper tapes and fabric tapes. The wrapping process may start in the spooled roll segment or intermediate roll segment instead of an end roll segment. Deviation of the relative group winding numbers or frequency of visits for a portion of the total roll segment wind does not depart from the spirit of the invention, that is to combine roll segments utilizing groups of spiral windings and conventional spooled roll segments to increase the stability and package roll diameter as compared to conventional spooled roll packages. 
     Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.