Support or pressure roll for a paper roll winder

Abstract

A roll for selective use as either a support drum or as a rider roll in a winder for winding a traveling paper web into a relatively large diameter wound web roll has a body with an outer, elastomeric cover. The elastomeric cover includes a pattern, open to the surface, arranged such that the percent of volumetric void for a unit of cover volume is such that the effective hardness of the cover ranges between about 30 Shore "A" to about 55 Shore "A" where the roll is a support drum, and between about 40 Shore "A" to about 65 Shore "A" when the roll is a rider roll. In addition, the elastomeric material has an absolute hardness of about 65 Shore "A", or less, for a support drum, and about 75 Shore "A", or less, for a rider roll, and a Poisson's ratio of between about 0.47 to about 0.499.

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThis invention relates to the winding of a traveling paper web, such as is produced by a papermaking machine. More particularly, this invention relates to the construction of either a support drum or a rider roll, or both, for use in a winder for winding such a traveling paper web. Still more particularly, this invention relates to the construction of a support drum or rider roll having an elastomeric cover having a unique combination of Poisson's ratio, absolute hardness and effective hardness to provide a relatively soft nip in support of the wound paper roll while utilizing a relatively hard elastomeric cover.2. Description of the Prior ArtIn the papermaking industry, a common form of winder for winding the substantially endless paper web produced by the papermaking machine comprises a pair of spaced, parallel support drums for supporting the wound paper roll being wound from the traveling paper web.It is known in the papermakin...

AI Technical Summary

Benefits of technology

The groove pattern in the cover surface need not have any particular configuration. While a dimpled surface pattern on the elastomeric cover is functionally superior, a diamond-shaped pattern or a tight spiral groove pattern is preferred. A symmetrical diamond pattern minimizes roll steering and thrusting forces. A tight spiral groove pattern minimizes noise and is more economical to make.

These characteristics of the winder support drum construction enable the instant center associated with the nip between the wound paper roll and the support drum to be shifted from inside the wound paper roll to inside the elastomeric cover of the support drum. This combination of physical parameters and characteristics of the support drum also result in an effectively much softer cover, which is desirable from a standpoint of lowering the unit pressure on the support drum surface, while providing the durability and longevity of a much harder cover.

It is contemplated that the absolute and effective hardnesses of rolls used as support drums in a two-drum type of winder do not both have to be the same. Thus, it is contemplated that the effective hardness of the back drum cover, commonly referred to as the number one drum in the papermaking industry, might be harder than the effective hardness of the cover on the front drum (number two drum).

Still another object of this invention is to provide an improved winder support drum or rider roll having an elastomeric cover with an open pattern in its surface.

Yet another object of this invention is to provide paper web winding apparatus for reducing interlayer shear stress between layers of the web in the wound web roll.

Problems solved by technology

A cover having a plurality of individual circular impressions, each extending ring-like about the circumference of the roll, is not preferred due to the likelihood that the superpositioning of a similarly depressed layers will result in a very unattractive ridge pattern on the surface of the wound web roll.

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