| 摘要 |
A pair of die rolls of novel construction are disclosed which act upon a continuous wire having a preliminary zig zag formation in order to impact the bends in the wire and thus narrow the formation, preparatory to use of the wire as a ring binder. Each roll has a continuous spiral groove with a first section of progressively narrowing width which is substantially wider than the wire bend which it accommodates, and a second section of constant width. A knob or projection is formed on at least one side wall of the groove in each roll at the juncture of the first and second sections, which impacts the wire bend as it passes, giving it a set.
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