Finally, someone has developed a chuck that can control 45-to-50-inch-diameter newsprint rolls. What's more, the new keyless chuck eliminates the need for metal end-caps on newsprint cores.
The chuck, created by Syzygen Inc. of Cary, N.C., was tested at the Myrtle Beach Sun News on their Goss Headliner press and at the Winston-Salem (N.C.) Journal on their new Mitsubishi press. Managers at both papers report reason to hope.
The new chuck should prove cost-effective for both newspapers and newsprint suppliers. It will help newspapers reduce newsprint waste by reducing web breaks and paster failures and by eliminating labor and freight costs incurred in handling and returning these cores. For newsprint suppliers, it means no labor costs to remove the metal caps and no recycling expenses.
So far, the Mitsubishi press places the highest demand on chucks because, as on most newer printing presses, reel chucks help accelerate and brake the newsprint roll. Presses with this feature often have problems with cardboard cores. High-speed presses running large-diameter rolls (45 inch - 50 inch) using keyless chucks tend to suffer damage to the ends of these cardboard cores. This causes the roll to unwind unevenly, precipitating problems during paster cycles. Rolls running unevenly also have trouble maintaining the color register on process-color leads.
The new chuck eliminates the need for metal end-caps by using three "fingers" that fit snugly in slots in the chuck. Each finger is roughly "L" shaped--the long leg of the "L" slips inside the chuck and the short leg of the "L" protrudes from a collar. When the clamping arrangement is inserted, the long ends of the fingers jut out of the chuck and exert a powerful clamping force inside the core.
A special feature of the chuck is that the fingers are held in place by an open ring placed in the grooves of the fingers and the main body. This ring expands when the fingers rotate and restores the fingers to the home position once the chuck is retracted from the core.
By controlling the fingers with this powerful but elastic steel ring, the chuck maximizes the hold on the core, sustains higher loads and handles cores of widely varying diameters.
The grip and adjustment capability of the clamping arrangement is also determined by the unique design of the fingers, which allows an optimal distribution of the contact forces. This even distribution of forces translates into a smooth unwinding of newsprint rolls, eliminating "flapping" during press runs.
The hold of the chuck can be regulated by changing the longitudinal force applied to the chuck or by changing the height of the fingers.
The new chucks should hit the market later this year. For more information, contact Glen W. McLaughlin, (919) 302-7249; fax, (919) 387-9078.
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Frank Balentine is NAA's press manager. E-mail, balef@naa.org; phone, (703) 648-1217; fax, (703) 648-1216.
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