PRODUCTION OF POINTED WORKPIECES
First Claim
1. In apparatus for forming a point on the end of a long slender workpiece, the combination of means for clamping the workpiece in place at a fixed location, a crosshead reciprocable toward and away from an end of said workpiece, a die carried on said crosshead and adapted to be forced over the end of the workpiece to produce a point of reduced cross-sectional area when said crosshead is forced toward the workpiece, a member having a generally conical surface which engages an edge of the end surface of said workpiece as said die is forced thereover to prevent said end from bowing from the longitudinal axis of the workpiece, said member being reciprocable along said axis, and means for yieldingly urging said member toward said crosshead whereby the member will move forwardly with said crosshead as the die is forced over said workpiece until the end of the workpiece engages said generally conical surface, whereupon further forward movement of said member with the crosshead is terminated and the pointed end of the workpiece is prevented from bowing by engagement with said generally conical surface.
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Abstract
Described are a method an apparatus for pointing long slender workpieces, characterized in that concentric, telescoping dies of successively smaller cross-sectional areas are forced over the end of the workpiece to thereby progressively reduce its crosssectional area in steps. Also described are a method and apparatus for preventing bowing or curving in a point formed by forcing a die over a workpiece to extrude the point.
13 Citations
6 Claims
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1. In apparatus for forming a point on the end of a long slender workpiece, the combination of means for clamping the workpiece in place at a fixed location, a crosshead reciprocable toward and away from an end of said workpiece, a die carried on said crosshead and adapted to be forced over the end of the workpiece to produce a point of reduced cross-sectional area when said crosshead is forced toward the workpiece, a member having a generally conical surface which engages an edge of the end surface of said workpiece as said die is forced thereover to prevent said end from bowing from the longitudinal axis of the workpiece, said member being reciprocable along said axis, and means for yieldingly urging said member toward said crosshead whereby the member will move forwardly with said crosshead as the die is forced over said workpiece until the end of the workpiece engages said generally conical surface, whereupon further forward movement of said member with the crosshead is terminated and the pointed end of the workpiece is prevented from bowing by engagement with said generally conical surface.
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2. The apparatus of claim 1 wherein said means for yieldingly urging said member toward said crosshead comprises fluid cylinder means having a piston rod coaxial with said axis of the workpiece, said member being carried on the end of said piston rod and said conical surface being on the side of said member opposite the piston rod, and means for pressurizing said fluid cylinder to yieldingly urge said member toward said crosshead, the pressure exerted by said fluid cylinder being such that forward movement of the member with the crosshead will stop when the generally conical surface on the member engages said end surface of the workpiece.
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3. The apparatus of claim 1 wherein said means for clamping the workpiece in place comprises a first cradle, a second cradle movable toward and away from the first cradle, clamping members carried in the cradles, each of the clamping members having a plurality of sides, and semicircular channels of different diameters formed in said dies and extending parallel to the axis of an article to be clamped, each channel in one member being of the same diameter as a corresponding channel in the other member whereby the members can be rotated to place the same sized channels in juxtaposition for reception of a workpiece to be clamped.
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4. The apparatus of claim 1 including a plurality of crossheads each of which carries an associated die, the dies on successive crossheads being of successively smaller diameters and coaxial with the axis of said workpiece, means for forcing the crosshead carrying the die of largest diameter along the axis of said workpiece whereby the die of largest diameter will pass over the end of said workpiece, means for forcing at least a second crosshead carrying a die of smaller diameter along the axis of said workpiece whereby said die of smaller diameter will pass over the reduced cross-sectional area formed by said largest diameter die while the first-mentioned die remains on the workpiece, said generally conical surface on said member engaging said end surface of the workpiece after said die of smaller diameter has passed thereover.
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5. The apparatus of claim 1 including hydraulic cylinder means for forcing said crosshead and the die carried thereby toward said workpiece, and wherein said means for yieldingly urging said member toward said crosshead comprises a pneumatic cylinder which exerts a force less than the force exerted by said hydraulic cylinder means.
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6. The apparatus of claim 1 wherein said crosshead carries a plurality of dies of successively smaller diameters, and means on said crosshead for moving successive ones of said dies into alignment with the axis of said workpiece.
Specification