Electro-hydraulic interface for a power tongs

摘要

A manually operable valve in a power tongs assembly has, in combination therewith, an electro-hydraulic interface module. The interface module comprises an electrically responsive solenoid valve connected in hydraulically parallel path to the manually operated valve. The manually operated valve may be selectively disenabled and the electrically responsive valve simultaneously enabled to permit electrical control of the power tongs assembly.