WO2001045926A1

WO2001045926A1 - Method for manufacturing tapered drums

Info

Publication number: WO2001045926A1
Application number: PCT/US2000/034649
Authority: WO
Inventors: Winfield C. Scott
Original assignee: Scott Winfield C
Priority date: 1999-12-22
Filing date: 2000-12-20
Publication date: 2001-06-28
Also published as: AU2443301A

Abstract

A method for manufacturing a tapered drum (10) including the steps of providing a plurality of generally arcuate component sheets (30) of paper and attaching the plurality of component sheets (30) of paper together in an end-to-end manner to form a generally arcuate composite sheet (40) of paper. The method further includes the steps of providing a rotatable frusto-conical mandrel (42), and wrapping the composite sheet (40) of paper about the mandrel (42) such as to form a tapered drum (10).

Description

METHOD FOR MANUFACTURING TAPERED DRUMS

The present invention is directed to a method for manufacturing fiber drums, and more particularly, to a method for manufacturing tapered fiber drums.

BACKGROUND OF THE INVENTION Fiber drums are widely used to store and transport a variety of materials. Most fiber drums are formed by wrapping a sheet of fibrous material, such as paper, around a cylindrical mandrel to form a cylindrical drum. However, empty cylindrical drums can not be efficiently stacked for storage or transportation and therefore require high volume in a warehouse, trailer, and the like. It is known that frusto-conical tubes (i.e. drums with tapered side walls) are nestable and stackable when they are empty. That is, one tapered drum can be largely received in another tapered drum, much like paper or styrofoam drinking cups, which greatly reduces the volume required to store empty drums. However, existing methods for forming tapered drums are time consuming and inefficient. Accordingly, there is a need for a method for quickly and efficiently manufacturing tapered, stackable fiber drums.

SUMMARY OF THE INVENTION

The present invention is a method for quickly and efficiently manufacturing tapered, stackable fiber drums. In a preferred embodiment, the invention is a method for manufacturing a tapered drum comprising the steps of providing a plurality of generally arcuate component sheets of paper and attaching the plurality of component sheets of paper together in an end-to-end manner to form a generally arcuate composite sheet of paper. The method further includes the steps of providing a rotatable frusto-conical mandrel, and wrapping the composite sheet of paper about the mandrel such to form a tapered drum.

Thus it is an object of the present invention to provide a method that quickly and efficiently forms tapered, stackable drums. Other objects and advantages of the present invention will be apparent from the following description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a tapered daim manufactured by the method of the present invention;

Fig. 2 is a schematic perspective view showing one method of forming component sheets; and

Fig. 3 is a schematic top view showing a composite sheet being wrapped around a mandrel.

DETAILED DESCRIPTION

As shown in Fig. 1, a tapered, stackable drum 10 has a bottom 12 and a side wall 14. The side wall 14 extends radially inwardly as it approaches the bottom 12. This enables another drum (not shown) to be stacked inside the drum 10 such that the other drum is substantially received in the drum. In order to form the drum 10, a longitudinal stock sheet 16 (Fig. 2) is unrolled from a source roller 18, and the stock sheet is conveyed in the direction of its longitudinal axis (shown by arrow A) to a take-up roller 20. The stock sheet is conveyed below a die 22 that stamps a component sheet 30 (Fig. 3) out of the stock sheet 16. The die 22 is lowered onto the stock sheet 16 by a set of arms 24. A void 26 is located where a component sheet has been stamped out of the stock sheet 16. After a component sheet is cut, the rollers 18, 20 are advanced until an uncut portion of the stock sheet 16 is located below the die 22. Die 22 then cuts another component sheet out of the stock sheet 16. This process is repeated until the desired number of component sheets are cut out of the stock sheet 16, and the take-up roller 20 collects the unutilized portions of the stock sheet 16. It should be understood that a variety of methods may be used to cut the component sheets 30 out of the stock sheet 16, and the stock sheet and die 22 shown herein is only one way in which the component sheets may be manufactured or obtained.

A number of component sheets 30 are shown in Fig. 3. Each component sheet 30 is generally "arcuate" shaped, and has an outer edge 32, an inner edge 34, and a pair of side edges 36, 38. The outer and inner edges 32, 34 are generally arcuate, and the radius of the outer edge 32 is greater than the radius of the inner edge 34. A plurality of component sheets 30 are attached together in an end-to-end manner to form a generally arcuate composite sheet 40. The component sheets 30 are attached together by tape, adhesives, or other methods in accordance with the material of the sheets 30. The stock sheet 16, component sheets 30, and composite sheets 40 are preferably formed of a fibrous material, such as paper. The composite sheet 40 shown in Fig. 3 may be formed or obtained by a variety of methods beyond the methods disclosed herein. For example, the composite sheet 40 need not be made of a series of smaller component sheets, and may be formed as a single, unitary sheet of paper.

After the composite sheet 40 is formed, it is wrapped around a frusto-conical mandrel 42 (Fig. 3) in a series of 360 degree rotations, or windings. The composite sheet 40 is wrapped around the mandrel 42 for multiple winds (typically 2-15 winds) to create a multiply drum. In one embodiment, each component sheet 30 is sized to form a single wind around the mandrel 42, such that a composite sheet 40 made of four component sheets 30 would form a four-ply drum. This simplifies the manufacturing process, and provides workers with an easy visual aid to determine that the composite sheet is of the proper size and length. The composite sheet 40 should be tightly wound around the mandrel during the windings. An adhesive is preferably continuously applied to the composite sheet 40 as it is wrapped around the mandrel 42 such that the adhesive is located on the wound composite sheet 40 between each ply. After sufficient windings, the drum formed on the mandrel 42 is removed from the mandrel, the adhesive is allowed to dry, and a bottom is attached in a known manner.

A drum 10 formed by his method is shown in Fig. 1. The resultant hollow, tapered drum 10 can be stacked with other tapered drums, and there is little or no flash to be trimmed from the diametral ends of the drum. The shape and size of the component sheets 30 and composite sheet 40 may be selected to vary the frustum length, diameter, cone angle, and other dimensions of the drum 10.

The size of the composite sheet 40 is selected such that only a single composite sheet is required to form a drum 10 that has the desired number of windings. Thus, each composite sheet 40 is preferably wound to form a single drum 10. Because each drum 10 is made of a single sheet of material (a composite sheet) as opposed to several smaller sheets, the manufacturing process is greatly simplified. For example, if the component sheets 30 were not joined together to form a composite sheet 40, a number of component sheets would have to be located and wound around the mandrel 42 to form a drum 10. The use of multiple sheets to form a single drum requires additional time and labor to properly locate each sheet, and increases the chances of folds or bubbles being formed in the drum. Thus, the use of a single sheet eliminates the problems associated with using multiple sheets to form a tapered, stackable fiber drum.

Having described the invention in detail and by reference to the preferred embodiments, it will be apparent that modifications and variations thereof are possible without departing from the scope of the invention.

What is claimed is:

Claims

1. A method for manufacturing a tapered drum comprising the steps of: providing a plurality of generally arcuate component sheets of material; attaching said plurality of component sheets of material together in an end-to- end manner to form a generally arcuate composite sheet of material; providing a rotatable frusto-conical mandrel; and wrapping said composite sheet of material about said mandrel such to form a tapered drum.

2. The method of claim 1 wherein each component sheet of material is stamped out of a roll of stock paper.

3. The method of claim 2 wherein said stock paper is located below a die and conveyed along its longitudinal axis such that said die cuts said component sheets of material out of said conveyed stock paper.

4. The method of claim 1 wherein each component sheet of material has a pair of opposide side edges, an outer edge having a radius, and an inner edge having a radius that is less than said radius of said outer edge.

5. The method of claim 1 wherein said component sheets of material are attached together by an adhesive.

6. The method of claim 1 further comprising the step of removing said tapered drum from said conic mandrel.

7. The method of claim 1 further comprising the step of adding an adhesive to said composite sheet of material as said composite sheet is wrapped about said mandrel.

8. The method of claim 1 wherein each component sheet is sized to form a single wind about said mandrel.

9. The method of claim 8 wherein when said drum is desired to have a predetermined number of plys, said composite sheet is comprised of said predetermined number of component sheets.

10. The method of claim 1 wherein each component sheet is sized to form a single ply of said drum.

11. The method of claim 1 wherein said composite sheet is sized to form a drum with the desired number of widings.

12. The method of claim 1 wherein said sheet of material is a sheet of paper.

13. A method for manufacturing a tapered drum having a predetermined number of plys comprising the steps of: providing a predetermined number of generally arcuate component sheets of paper, said predetemiined number of component sheets corresponding to said predetermined number of plys; attaching said predetermined number of component sheets together in an end- to-end manner to form a generally arcuate composite sheet of material; providing a rotatable frusto-conical mandrel; and wrapping said composite sheet of material about said mandrel such to form a tapered drum, wherein each component sheet forms a single wind about said mandrel.

14. A tapered drum formed by the steps of: providing a plurality of generally arcuate component sheets of paper; attaching said plurality of component sheets of paper together in an end-to- end manner to form a generally arcuate composite sheet of paper; providing a rotatable frusto-conical mandrel; and wrapping said composite sheet of paper about said mandrel such to form a tapered drum.