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Expanding surface Spreader Roller – Continuous Rubber Sleeve Type

Description:

This type of spreader is manufactured with a rubber sleeve stretched across its face. On each end of the rubber sleeve there are end collars that clamp and hold the sleeve in place. The end collars are mounted on bearings and an adjustable axle. The sleeve is mounted across a series of flexible rubber disks. The rubber sleeve and end caps rotate together.

Theory of operation:

This roller must be incorporated as a dead shaft idler roller, in order to operate properly. The continuous rubber sleeve is pre-loaded across the face of the roller. The end collars are clamped on to each end of the rubber sleeve. The end collars are then canted with an adjustment screw and flange-axle assembly. The canting adjustment is designed so that the collars are facing each other on one side of the roller face and they are away from each other on the opposite (180°) side of the roller. The continuous rubber sleeve stretches from the point where the collars are facing each other, to where the collars are away from each other. The sleeve then contracts for the next 180° of rotation, from where the end collars are facing away from each other to where they are facing toward each other. Bottom line, the rubber sleeve physically stretches from the short side of the rubber sleeve to the long side of the rubber sleeve, then contracts again. The web enters the contracted side of the rubber sleeve and exits on the expanded side. As this roller rotates, the stretching action of the rubber sleeve spreads the web.

Recommended wrap angle for this roller is from 90° to 180°. More wrap (up to 180° maximum) means more spreading. The amount of spreading is directly proportional to the amount of wrap angle. In other words 180° of wrap will provide for 100% of possible spreading, 90° of wrap will provide 50% of possible spreading, 45° of wrap will provide 25% of possible spreading, etc. Lead-in and lead-out distances are not critical in the application of this type of spreading device, because all or most of the web spreading is taking place on the roller face, not in the entry span to the roller.

Advantages:

• This type of spreader is an aggressive wrinkle removal device.

• Spreading amount is adjustable from 0% (no spreading) - 100%.

• Spread adjustment can be made from each end of the roller, independent of each other, while the machine is running and with standard tools.

• This roller is linear across its face, so tension remains evenly distributed across the roller face.

• This roller will not distort or tear the center or edges of a web.

• It is available with a multitude of different sleeve compounds including abrasion, chemical and heat resistance and release for adhesive applications.

• Roller surface is smooth and linear so it will not mark, scratch or deform a web.

• This roller is used with all types of webs.

Disadvantages:

• Web speeds are a consideration when utilizing this roller. If the web speed causes the sleeve to balloon, as a result of centrifugal force, then the effect on web may be reduced.

• The sleeve is stretching and contracting with every revolution, so the continuous rubber sleeve will degrade over time.

• Although spreading does occur across the full width of the roller face, most of the spreading occurs toward the ends of the roller face, so the amounts of spreading are not even in measured increments across the face of this roller.

The future of spreader roller technology:

As converting processes run thinning webs faster and wider, more answers to solve wrinkling problems are required. Today’s converter wants to run more types of webs with the highest level of productivity. Converters will be looking for spreader rollers to remove wrinkles, at high speeds, with no web distortion. Continuing advances in spreader roller technology must strive to supply converters with products and service to gain the highest level of productivity.