No. 91-1697. Argued December 11, 1991. Decided July 23, 1992. Paul J. Spielberg, Michael J. Gan (argued), N.L.R.B., Contempt Litigation Branch, Aileen A. Armstrong, N.L.R.B., Appellate Court, Enforcement Litigation, Washington, D.C., Joseph A. Szabo, Director, N.L.R.B., Milwaukee, Wis., for petitioner. Paul Cady, Paul J. Zech (argued), Felhaber, Larson, Fenlon Vogt, Minneapolis, Minn., for respondent. Before FLAUM, and RIPPLE, Circuit Judges, and WILL, Senior District Judge. The Honorable Hubert