US3488242A - Apparatus for making multi-ply sheet product - Google Patents

Description

Jan. 6, W79 A. c. BERRY Q I 9 12 APPARATUS FOR MAKING MULTI-PLY SHEET PRODUCT Filed June 23, 1966 United States Patent 3,488,242 APPARATUS FOR MAKING MULTI-PLY SHEET PRODUCT Andrew C. Berry, Appleton, Wis., assignor to Kimberly- Clark Corporation, Neenah, Wis., a corporation of Delaware Filed June 23, 1966, Ser. No. 559,766 Int. Cl. B65h 81/00 US. Cl. 156428 1 Claim ABSTRACT OF THE DISCLOSURE A mandrel having a cylindrical portion on which sheet material may be spirally wound as the sheet material is pulled off the free end of the mandrel which is 111 the form of a straight edge is disclosed. The mandrel has a transition section connecting the straight edge with the cylindrical portion. The transition section in cross section is in the form of flat sided ovals.

The invention relates to papermaking machines and more particularly to machines for making a multi-ply product of sheet material, such as paperlike material.

It has been previously proposed, for example, in Patent No. 1,515,792, to R. B. Respess, to spirally wind a web of sheet material about a central cylindrical mandrel and to pull the sheet material from the end of the mandrel between a pair of pressure rollers for flattening the web so wound into a double ply product and for bonding the plies together. A suitable adhesive may be inserted between the plies of the multi-ply product in order to cause the plies to adhere to each other. It has been found with such a process, however, that in changing the form of the web from cylindrical to flat form, the web wrinkles and distorts so that a final wrinkled two-ply product results.

It is an object of the present invention to provide an improved machine of this type and, in particular, to provide a mandrel of improved shape so that, as the wound web travels longitudinally of the mandrel, it does not wrinkle substantially and results in a correspondingly unwrinkled multi-ply product.

The invention consists of the novel constructions, arrangements and devices to be hereinafter described and claimed for carrying out the above stated objects, and such other objects, as will be apparent from the following description of a preferred form of the invention, illustrated with reference to the accompanying drawing, wherein:

FIG. 1 is a perspective view of a winding machine embodying the principles of the invention and shown in operation with a web of sheet material being wound about the mandrel of the machine;

FIG. 2 is another perspective view of the machine with the sheet material web being broken off and with certain parts of the machine being broken away for clarity of illustration of certain other parts of the machine;

FIG. 3 is a side elevational diagrammatic view of the mandrel of the machine; and,

FIG. 4 is a sectional view taken on line 4-4 of FIG. 3.

Like characters of reference designate like parts in the several views.

Referring now to the drawing, the illustrated machine may be seen to comprise a central mandrel 9 having a cylindrical portion 10, and a transition section 11 formed by opposite flat portions 12 and 13 and opposite round portions 14 and 15. The portions 12 to 15 terminate in a straight edge 16. The mandrel 9 is held stationary and vertical by means of a downwardly disposed fixed rod 17.

A rotatable disc 18 is disposed above the mandrel 9, and it has the rod 17 passing through the center of the "ice disc. A downwardly depending coreshaft 19 is fixed with respect to the disc 18 by means of a bracket 20 and carries a roll of paperlike or other sheet material 21 rotatably disposed on the coreshaft 19.

A pair of nipped calender rolls 22 and 23 are disposed below the mandrel 9 with the straight edge 16 immediately above the nip between the rolls 22 and 23. The nip of the rolls 22 and 23 extends parallel to the straight edge 16 and lies on the longitudinal center 24 of the mandrel 9.

In operation, as illustrated in FIG. 1, the disc 18 and thereby the roll 21 are rotated about the longitudinal center 24 of the mandrel 9, and the web 21 is wound onto the cylindrical portion 10 of the mandrel. The web 21 slides downwardly along the surface of the mandrel and, in particular, on the portions 12 to 15, down to the straight edge 16, and the web passes from the straight edge 16 to and between the calender rolls 22 and 23 and from thence to a suitable takeup roll or reel (not shown). The web 21 is helically wound on the cylindrical portion 10 and while on the portion 10 is of course in cylindrical shape; and the cylindrical of sheet material is flattened as the web travels downwardly over the portions 12 to 15 to the straight edge 16 and through the nip between the rolls 22 and 23. The rolls 22 and 23 are driven by any suitable means (not shown) so as to pull the spirally wound web 21 off the free end of the mandrel 9 defined by the'straight edge 16.

Preferably the web 21 has some thermoplastic fibers within it or else has thermoplastic adhesive within it and at least one of the rolls 22 and 23 is heated, as by an internal electric heater 25, so that as the web passes between the rolls 22 and 23, the two plies formed from the flattened Web cylinder are thereby caused to adhere to each other to form a unitary two-ply sheet material product. Preferably also, the sheet material web 21 in its original roll form has longitudinally extending, substantially aligned, synthetic filaments or has aligned, staple fibers within it; and, due to these filaments or fibers, the sheet material web 21 is very strong in the longitudinal direction. Since the web 21 is wound spirally on the mandrel 9, and since its cylindrical form is flattened as the web passes between the calender rolls 22 and 23, one ply of the composite material extends at 45 with respect to the longitudinal dimension of the final composite web, and the other ply also extends at 45 to the web but at with respect to the other ply. Thus strength is imparted to the composite sheet material product primarily in two directions extending at 90 with respect to each other and both extending at 45 with respect to the longitudinal dimension of the composite sheet material product.

It is very desirable that the web 21, as it passes downwardly on the mandrel 9 and along the transition section 11 to the straight edge 16, remain in unwrinkled condition, otherwise the wrinkles are ealendered into the composite laminated final product and the final product is not smooth. I have discovered that if the transition section 11 of the mandrel 9 is made so that, in cross section, the side portions 12 and 13 are flat and the rounded end portions 14 and 15 are circular, considering the mandrel 9 in cross section between the cylindrical portion 11 and the straight edge 16, substantial Web wrinkling does not occur. Also, the perimeter of each cross section of the transition section 11, from the cylindrical portion 10 to the straight edge 16, shall preferably be the same and equal to the circumference of the cylindrical portion 10.

Referring to thediagrammatic illustration of the mandrel shown in FIG. 3 and to the cross section of the mandrel shown diagrammatically in FIG. 4, which is taken through the transition section 11 between the cylindrical portion 10 and the straight edge 16 on any plane spaced a distance Z from the lower end of the cylindrical portion 10 and disposed at right angles to the longitudinal center line 24 of the mandrel, it will be apparent that the perimeter of such a cross section, if it is to be equal to the circumference of the cylindrical portion 10, shall be equal to 21rr where r is the radius of the cylindrical portion 10. If this relationship is to hold along the straight edge 16, the length of the straight edge must, therefore, be equal to 1rl which is one-half the circumference of the cylindrical portion 10. I have found that the perimeters of the various cross sections through the transition section 11 will also be equal to 21rr (the circumference of the cylindrical portion if n equals and if the length of each of the flat portions 12 and 13 in cross section equals Zm' /L, where L is the distance between the lower end of the cylindrical portion 10 and the straight edge 16, Z is the distance from the lower end of the cylindrical portion 10 to the plane of the particular cross section being considered and r is the radius of curvature of the end portions 14 and in cross section. The following mathematical equations may be utilized to prove that the perimeter (designated as P) of any cross section taken through the transition section 11 of the mandrel 9, below the cylindrical portion 10, is equal to the circumference of the cylindrical portion which is 21 if the radius r equals and if the length of each of the flat sides 12 and 13, as seen in cross section, equals Z1rr /L:

P= (Z+L-Z) P=21rr =Circumference of cylindrical portion 10 Utilizing Equation 1 it will be apparent that if Z equals zero for the cross section at the lower end of the cylindrical portion 10, the first term of Equation 1 is zero and the second term of Equation 1 equals 21rr satisfying the one end condition for the transition section 11 of the mandrel. For the other end condition, when Z equals L at the straight edge 16, the second term ofEquation 1 is zero and the perimeter P equals 21rl thus satisfying the other end condition. For each intermediate cross section of the transition section 11 of the mandrel 9 comprising the portions 12 to 15, both terms of Equation 1 have finite values and add up to 21rr In view of the fact that the perimeter of the mandrel 9, considering it in cross section from one end to the other, is the same, and in view of the fact that the portions 14 and 15 are circular and the portions 12 and 13 are flat, there is no substantial wrinkling of the Web 21 due to web distortion as the web travels down the mandrel 9 in producing bias cross laid product. Therefore, the web 21, as it is wound onto the mandrel 9, travels at a substantially constant linear speed; and the amount of overlap or the amount of space between successive turns of the spirally wound web 21 may be quite accurately controlled.

It is contemplated that, for best results, the dimension L is preferably substantially greater than multiples of the radius r in view of the fact that there is some slight stretching of the material 21 in portions as it travels along the transition section 11, which stretching is, however, decreased as the dimension L is increased with respect to the radius r Material of the type above mentioned, for example, allows a 2% percent stretch within its elastic limit (measured on the 45 bias direction of the material); and it can be shown mathematically that if the dimension L is equal to or greater than 4r the amount of stretch of the material 21 as it passes over the transition section 11 is substantially less than the 2% percent stretch capabilities of the material 21. Therefore, I prefer that the dimension L shall be equal to or greater than 4r I wish it to be understood that the invention is not to be limited to the specific constructions, arrangements and devices shown and described, as it will be apparent to those skilled in the art that changes may be made without departing from the principles of the invention.

What is claimed is:

1. In apparatus for making a multi-ply sheet product, a mandrel having a cylindrical portion on which sheet material may be spirally wound as the sheet material is pulled oif a free end of the mandrel, said free end being in the form of a straight edge and said mandrel having a transition section connecting said straight edge with said cylindrical portion, said transition section in cross section from said cylindrical portion to said straight edge being in the form of a continuous series of flat sided ovals; the flat sides of the oval of each cross section of said transition section having a length of Z1rI /L and the ends of said oval being circular and having a radius of where L is the length of the transition section from said cylindrical portion to said straight edge, Z is the distance from said cylindrical portion to the particular cross sectional plane in said transition section being considered, r is the radius of said cylindrical portion, and the dimension L is not less than 4r References Cited UNITED STATES PATENTS 1,504,255 8/1924 MacDonald 156- 194 XR 1,515,792 11/1924 Respess l56179 XR 1,604,273 10/ 1926 Gammeter l56l94 XR 1,676,351 7/1928 Robinson l56l94 XR 1,915,626 6/1933 Spohn l56l94 XR 2,847,056 8/ 1958 Vanlaer l56428 XR 2,797,728 7/ 1957 Slayter et a1. l56431 XR HAROLD ANSHER, Primary Examiner D. I. FRITSCH, Assistant Examiner US. 01. X.R. 156189, 195, 459

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