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Lighten the Load

There are many methods to supporting unwind and rewind roll cores in center driven applications. Air shafts, air chucks, mechanical chucks and core cones are the most common methods. Typically, air shafts are individually designed to support the full width of your widest roll and include journals designed to fit your machines bearing support.

Air chucks, mechanical chucks and core cones are core support methods that are more standard or off-the-shelf in nature. They are typically shorter in length than a full length air shaft and support the core of your unwind or rewind roll at its ends. These types of core chuck devices must be mounted via a temporary locking mechanism to a thru shaft and slid along that thru shaft to accommodate for varying roll widths. Once their proper position is determined on the thru shaft, they are locked in place to support the core. Engagement to the core is either through air inflation or mechanical locking.

The center or thru shaft is often times a solid steel shaft with ends designed to fit the bearing supports of the unwind or rewind shaft. One method to decreasing the weight of this support shaft is to manufacture it from hollow mechanical tubing. Beam strength of shafting comes mainly from the outside diameter. Some stiffness will be lost by making the thru shaft hollow but this is typically a very small amount. The weight savings compared to stiffness loss makes this option very attractive when considering ways of lightening the center shaft. Solid steel ends can be mounted and welded in place on each end of the hollow mechanical tubing to fit your unwind or rewind stand. Obviously, weight savings and deflection of hollow shafting versus solid shafting can be calculated for any individual application and determination of feasibility for your application can made.

Machine operators must handle whatever core support method your machine utilizes when roll changes must be made. Lightening the center shaft will ease this operation.

Jeff Damour, Converter Accessory Corporation
201 Alpha Road, Wind Gap PA 18091

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