Commercial Shearing, Inc.

Robert M Birch

Warren E Brown

A method and apparatus for tunnel lining is provided made up of arcuate liner segments having a formed body with two end walls and two substantially parallel sidewalls, at least two pins extending from one sidewall intermediate its length in the median plane of the body and transverse to said sidewall, a like number of openings in the other sidewall each adapted to receive one of said at least two pins from two adjacent interfitting segments and locking means in said opening permitting insertion of said at least two pins in said openings of adjacent segments and lockingly engaging the same against removal and urging said two adjacent fittings into tight end to end engagement.

Growing community of inventors

Youngstown, OH, United States of America

Robert M Birch