US 5,921,128 AGranted

Method and apparatus for cold rolling tubes

AssigneeMannesmann Aktiengesellschaft

InventorsHorst Stinnertz, Jurgen Schmidt

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Abstract

A method and apparatus for continuously feeding rolling stock through a cold pilger rolling mill. A rolling stock--either a continuous or so-called "endless" piece, or a plurality of serially fed, spaced-apart pieces--is initially fed into a roll stand by a feed side drive or transporting arrangement, and thereafter, drawn through the rolling mill by a delivery side drive or transporting arrangement that is located in a rolling direction, i.e. downstream, from the feed side drive arrangement. Once the leading free end of the rolling stock is grasped by the delivery side transporting arrangement, the feed side transporting arrangement ceases to feed the rolling stock through the rolling mill, i.e. forward feeding of the rolling stock is exclusively controlled by the delivery side transporting arrangement. Thus, the critical compressive stresses and/or buckling stresses typically experienced by the rolling stock as a result of pushing the stock through the rolling mill are prevented and the disruptions in the rolling process caused by these stresses are accordingly also prevented. The transporting arrangements are operable independent of each other and at transporting or rolling speeds dependent upon each other.

Claims14

Dependent claims

An apparatus for forming a thin-walled rolling stock in a cold pilger rolling mill having a feed side and a delivery side, the rolling stock being movable through the rolling mill in a rolling direction defined from the feed side to the delivery side, said apparatus comprising:

a reciprocating roll stand located between the feed side and the delivery side and having two rolls each having a reduced diameter portion defined circumferentially thereabout, said reduced diameter portions together defining a shaping zone in said reciprocating roll through which the rolling stock passes as the rolling stock is moved in the rolling direction and by which the rolling stock is formed as the rolling stock passes therethrough, said roll stand being reciprocally movable between first and second dead center positions, the rolling stock being rotated within said roll stand when said roll stand is positioned at at least one of said first and said second dead center positions and exiting said roll stand at a second predetermined rolling speed;
a delivery side transporting arrangement located at the delivery side of the rolling mill and in the rolling direction from said roll stand and having a speed regulating means, said delivery side transporting arrangement circumferentially grasping the rolling stock as it exits said roll stand for rotating and moving the rolling stock through the rolling mill in the rolling direction at a first predetermined rolling speed;
a feed side transporting arrangement located at the feed side of the rolling mill, said feed side transporting arrangement periodically rotating and moving the rolling stock through the mill in the rolling direction, the movement of the rolling stock by said feed side transporting arrangement being dependent upon said delivery side transporting arrangement;
means for measuring the second predetermined rolling speed as the rolling stock exits the roll stand and before the rolling stock is grasped by the delivery side transporting arrangement and generating an output;
and
means for increasing the first predetermined rolling speed in response to said output of said means for measuring said second predetermined rolling speed.

3 more elements

a reciprocating roll stand located between the feed side and the delivery side and having two rolls each having a reduced diameter portion defined circumferentially thereabout, said reduced diameter portions together defining a shaping zone in said reciprocating roll through which the rolling stock passes as the rolling stock is moved in the rolling direction and by which the rolling stock is formed as the rolling stock passes therethrough, said roll stand being reciprocally movable between first and second dead center positions, the rolling stock being rotated within said roll stand when said roll stand is positioned at at least one of said first and said second dead center positions;
and
a delivery side transporting arrangement located at the delivery side of the rolling mill and in the rolling direction from said roll stand, said delivery side transporting arrangement circumferentially grasping the rolling stock as it exits said roll stand for rotating and moving the rolling stock through the rolling mill in the rolling direction at a first predetermined rolling speed, wherein said first predetermined rolling speed is operative for preventing buckling stresses between successive ones of said rolling stock.

Dependencies are inferred from the claim text.