Ribbed core dual wall structure

Details Ribbed core dual wall structure Ribbed core dual wall structure

2000-07-27

2002-06-18

Jillions, John M. (Department: 3653)

Winding, tensioning, or guiding

Coil holder or support

Spool or core

C242S610500, C242S610600, C242S613500, C138S148000

Reexamination Certificate

active

06405974

ABSTRACT:

GENERAL FIELD OF THE INVENTION
This invention relates to generally tubular articles such as cores for rolled goods like carpets and plastic film. It more particularly refers to such cores that are light in weight and have unusually high crush resistance. It further relates to decorative toy articles made from such tubular articles.
BACKGROUND OF THE INVENTION
Cores for all kinds of rolled goods, such as plastic film, carpeting, paper products, and the like, are well known. In many instances, these cores are simply hollow cylindrical rolls of cardboard or other materials. In other cases, these cores may be solid plastic, wood or metal rods.
In one very old patent, U.S. Pat. No. 3,627,221, there is described a decorative end plug for rolled paper, such as newsprint. The end plug is made up of a centrally located opening for receiving an axially disposed shaft, a generally flat, solid, disc like portion
16
disposed radially about the shaft receiving axial opening
18
, and a peripheral rim portion
20
disposed radially around the disc portion
16
. From a consideration of FIG.
1
of this patent, it appears that a core
12
of the paper roll
10
is intended to fit about the rim portion
20
. Put another way, the described end plug is intended to fit within the core of the roll of paper and the shaft (unnumbered) that will support the assembly is intended to pass through the axial opening
18
in the end plug.
The peripheral rim portion
20
of this disclosed end plug appears to be composed of a “U” shaped member that is made up of two concentric elements
26
and
30
that form the arms of the “U”. A series of webs
34
and
36
appear to span the top of the “U”. These webs and the arms of the “U” are so arranged as to form generally triangular areas or cells
38
. This end plug is intended to help to support the ends of the paper roll on its cylindrical paper core. The depicted end plug is generally flat in cross section and is not disclose to pass axially all the way through the paper roll or its cylindrical paper core. In fact, this end plug is characterized by having a diameter that is substantially larger than its depth, that is, it is a disk-like shape rather than a tube-like shape. The end plug is said to taper inwardly in thickness from its periphery toward the central opening in order to increase its resiliency during its insertion into the end of the paper roll. The '221 patent says that the depicted flat, disc like end cap may be made of molded plastic, such as polyethylene. It is clear that the depicted end cap is not suited to have paper or other flat goods rolled up on it, but is only suited to be inserted into the end of an already made roll of paper or the like. Despite the support that the end plug of the '221 patent may give to the ends of the internal tubular paper central tube, the paper core
12
must be self supporting and able to withstand the weight of the paper rolled thereon over substantially the whole of its length.
It is to be noted that the '221 patent states that the disclosed end plug is intended to help protect the already made roll from damage during loading and unloading and during transit, not during the making of the roll of paper. This distinguishes that end plug of the prior art from the core structure of the instant invention which is intended for use in creating the roll of flat goods, especially stretch or shrink wrap plastic film (hereafter generally referred to as shrink wrap plastic film). The crush stress that is applied to the core by shrink wrap plastic film is substantially greater that what is applied by newsprint, and this stress increases with the amount of shrink wrap film that is wound on the central core. It increases further with the shrinkability of the film being wound and with the speed of winding of the film. Therefore, modern wrapping techniques use solid cores to support most industrial sized rolling of flat goods, from carpet to plastic film.
Solid wood plastic or steel rollers are quite heavy and add to the shipping costs of the material rolled on them. Further, solid cores of these materials are expensive and, although efforts at recycling have been attempted, they have not met with great success. The cost of the cores must then be added to the cost of the material that is wrapped on the cores. It is obvious that making the cores hollow and thin walled will substantially reduce their weight, and therefore their cost, and will also reduce the weight of the entire rolled product whereby reducing shipping costs as well. The problem with using hollow cores, however, is that hollow tubes necessarily have lower crush strength than solid cylinders of the same diameter and material. Further, and the thinner the wall of hollow cores, the less is their crush resistance. It has therefore been thought that the tradeoff between the weight and cost of the core and the crush strength of the core was just something the art had to accept, with the proper core selected for each application.
OBJECTS AND DESCRIPTION OF THE INVENTION
It is an important object of this invention to provide a hollow core tubular article, that can be used for, among other things, supporting rolled goods thereon.
It is an object of this invention to provide such a tubular article that is lighter in weight than previous similar articles, and yet has a substantially higher crush resistance than has been achieved in the past.
It is a further object of this invention to provide such a tubular article that has sufficient radial crush strength to support the stress of substantial quantities of flat goods, particularly shrink wrap plastic film, thereon.
It is another object of this invention to provide a method of making relatively inexpensive, crush resistant hollow tubes that are suited for use as cores in supporting rolled flat goods.
It is a still further object of this invention to provide novel means for improving the roundness of tubular articles, particularly hollow tubular articles that are made by an extrusion method.
It is a still further object of this invention to provide an improved method of making tubular articles of substantial length that have more consistent diameters than has been achievable in the past.
It is still another object of this invention to make a novel entertainment or toy article that is derived from the hollow tubular articles made according to this invention.
Other and additional objects of this invention will become apparent from a consideration of this entire specification, including the drawing hereof.
In accord with and fulfilling these objects, one aspect of this invention is an elongated hollow tubular article, sometimes referred to herein as a composite tube, comprising a smaller diameter inner, generally hollow, tubular element and a larger diameter outer, generally hollow tubular element with at least one web of material disposed between, and attached to, both the inner and outer elements. The intermediate web(s) of material enable the inner and outer tubes to maintain their radial spacing from each other. Preferably there are a plurality of such webs of material disposed between, and attached to, both the inner and outer elements or walls. These plural webs are suitably spaced from each other. Most preferably, these ribs or webs are substantially equidistantly spaced apart angularly (sometimes hererafter referred to as radially spaced apart ribs) within the toroidal area between the inner and the outer tubes. These plural webs or ribs are preferably disposed in locations such that at least some of them, and preferably all of them, contact, and support, the radial spacing of both the inner and outer tubes, respectively, at locations where other such ribs also contact the inner and outer walls respectively. Put another way, each rib contacts the inner and outer tube and at the same time contacts, or at least is close to the point where the next adjacent rib also contacts, either the inner or the outer tubular wall, respectively. In one embodiment of this invention, this configuration causes a rib to be

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