No. 73-1041. Argued June 12, 1973. Decided October 24, 1973. Elliott Moore, Asst. Gen. Counsel, Peter G. Nash, Gen. Counsel, Patrick Hardin, Associate Gen. Counsel, John S. Irving, Deputy Gen. Counsel, John D. Burgoyne, Atty., N.L.R.B., Washington, D.C., for petitioner. Marshall J. Conn, Pittsburgh, Pa., for respondent; Clifford A. Weisel, Weisel, Xides Conn, Pittsburgh, Pa., on brief. Robert C. Knee, Jr., Dayton, Ohio, for intervenor; Knee, Snyder Parks, Sorrell Logothetis, Dayton, Ohio, on brief