No. 78-1183. Heard September 19, 1978. Decided October 24, 1978. R. Clay Bennett, Chicago, Ill., for petitioner. Richard A. Cohen, N.L.R.B., Washington, D.C., for respondent. Joel A. D'Alba, Chicago, Ill., for intervenor. Petition for review from the National Labor Relations Board. Before CUMMINGS, PELL and WOOD, Circuit Judges. CUMMINGS, Circuit Judge. Cerlo Manufacturing Corporation has asked us to review a decision by the National Labor Relations Board finding that Cerlo's refusal to bargain with