Method for drawing seamless metal tubing particularly copper tubing under inclusion of a floating mandrel and a diameter reducing die
First Claim
1. Method for drawing seamless metal tubing particularly copper tubing under inclusion of a floating mandrel and a diameter reducing die wherein the wall thickness is reduced under cooperation of the mandrel and of the die in an action zone defined by a drawing gap between the mandrel and the die, there being means to apply a drawing force to the drawn tube downstream from the die, comprising the steps of:
- connecting a plurality of tubings end-to-end to each other thereby providing a joint in each instance of connection;
normally and regularly drawing the tubing in portions not having any joint;
shifting the mandrel away from the action zone of the die as a joint between two of said tubings approaches the mandrel and keeping the mandrel out of the action zone in relation to the die as the joint passes through the die;
hollow drawing the tubing so that as a consequence of the shifting step, only a portion of the combined tubing including the joint is deformed, for a diameter reduction without concurring wall thickness reduction;
returning the mandrel to the action zone of the die following passage of the joint through the die; and
applying a pulling force to resume drawing to be effective downstream from the die but upstream from the joint that just passed through the die.
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Accused Products
Abstract
A method for drawing seamless metal tubing particularly copper tubing under inclusion of a floating mandrel and a diameter reducing die wherein the wall thickness is reduced under cooperation of the mandrel and of the die in an action zone defined by a drawing gap between the mandrel and the die, a drawing force is applied to the drawn tube downstream from the die, a plurality of tubings are connected to each other end-to-end thereby providing a joint in each instance of connection; normally and regularly the tubing is drawn in portions not havng any point; the die is shifted in the direction of drawing while holding the mandrel as the joint approaches, or the mandrel is shifted while the die is held; the tubing is hollow drawn in and adjacent to the joint without the mandrel being in the action zone of the die for reducing the diameter of the tubing with little or no concurring reduction in the wall thickness; subsequently the mandrel or the die is returned to the action zone of the die after the joint has passed through the die so that regular drawing can be resumed.
18 Citations
19 Claims
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1. Method for drawing seamless metal tubing particularly copper tubing under inclusion of a floating mandrel and a diameter reducing die wherein the wall thickness is reduced under cooperation of the mandrel and of the die in an action zone defined by a drawing gap between the mandrel and the die, there being means to apply a drawing force to the drawn tube downstream from the die, comprising the steps of:
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connecting a plurality of tubings end-to-end to each other thereby providing a joint in each instance of connection;
normally and regularly drawing the tubing in portions not having any joint;shifting the mandrel away from the action zone of the die as a joint between two of said tubings approaches the mandrel and keeping the mandrel out of the action zone in relation to the die as the joint passes through the die; hollow drawing the tubing so that as a consequence of the shifting step, only a portion of the combined tubing including the joint is deformed, for a diameter reduction without concurring wall thickness reduction; returning the mandrel to the action zone of the die following passage of the joint through the die; and applying a pulling force to resume drawing to be effective downstream from the die but upstream from the joint that just passed through the die. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 16, 17, 18, 19)
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9. Method for drawing seamless metal tubing particularly copper tubing under inclusion of a floating mandrel and a diameter reducing die wherein the wall thickness is reduced under cooperation of the mandrel and of the die in an action zone defined by a drawing gap between the mandrel and the die, there being means to apply a drawing force to the drawn tube downstream from the die, comprising the steps of:
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connecting a plurality of tubings end-to-end to each other thereby providing a jooint in each instance of connection; normally and regularly drawing the tubing in portions not having any joint; shifting the die in the direction of drawing while holding the mandrel as the joint approaches; hollow drawing the tubing in and adjacent to the joint without the mandrel being in the action zone of the die for reducing the diameter of the tubing with little or no reduction in the wall thickness; returning the mandrel in the action zone of the die after the joint has passed through the die and resume drawing. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification