Waist elastic applicator for diaper or similar article

DETAILED DESCRIPTION The present invention is an apparatus for applying tensioned elastic transversely to a moving web of material.
The apparatus is suitable for application of the elastic at high line speeds without interruption or intermittent operation of the moving web.
It is especially well adapted for the application of waist zone elastic-to disposable diapers or similar products.
A first essential element of the invention is a pair of spaced apart elastic transfer wheels.
These are located in a mirror image relationship transversely across the moving web to which the elastic is to be applied.
The transfer wheels each lie in planes which, when projected onto the plane of the web, describe lines parallel to the longitudinal axis of the web.
The centers of the transfer wheels are located so that the circumferential edges at one point are adjacent to and essentially tangent to the plane of the web.
The two transfer wheels are inclined relative to each other so that the distance between them is greatest where a point on their circumference lies adjacent the web and least where a point on their circumference is at the greatest distance from the web.
An elastic supply system provides an untensioned elastic strip to the transfer wheels at or adjacent to the point of least distance between them.
Each transfer wheel has an elastic retainer which grips the elastic at the point of application, holds it in place during about 180.
degree.
rotation of the transfer wheels, and then releases it at the plane of the web.
A drive system rotates the transfer wheels at a circumferential speed esssentially equal to the linear speed of the moving web.
The elastic is applied to the transfer wheels at the point where their edges are closest together and released where they are furthest apart and is stretched an amount equal to the ratio of these two distances.
Normally the stretched elastic will be adhesively bonded to the moving web.
The system for supplying the elastic strips to the transfer wheels may be a cylinder or drum which has its longitudinal axis normal to the longitudinal axis of the moving web