Patent ID: 6725701
Filing Date: 2004-04-27
Classification: B21B

Abstract:
A cluster type multistage rolling mill comprising:an upper group of rolls arranged above a pass line; a lower group of rolls arranged below the pass line; a top inner housing for containing said upper group of rolls; a bottom inner housing for containing said lower group of rolls; an operating side outer housing and a driving side outer housing, said outer housings being arranged at a distance from one another and containing said top and bottom inner housings; a top side supporting means for supporting an upper side of said top inner housing to said outer housings in the operating side and the driving side each at two points in a front side and in a back side with respect to a pass direction, said top side supporting means being arranged in the upper side of said top inner housing and between said operating side and said driving side outer housings; and a bottom side supporting means for supporting a lower side of said bottom inner housing to said outer housings in the operating side and the driving side each at one point in the middle with respect to the pass direction, said bottom side supporting means being arranged in the lower side of said bottom inner housing and between said operating side and said driving side outer housings; and wherein a height of said bottom inner housing that is a distance between the uppermost portion thereof and a bottom portion thereof on which said bottom side supporting means is disposed is greater than a height of said top inner housing that is a distance between upper portions thereof on which said top side supporting means are disposed and the lowermost portion thereof so that a ratio of a vertical rigidity of said top inner housing to a vertical rigidity of said bottom inner housing is a value within a range of 1.02 to 1.18.