Varco International, Inc.

Johannes W Van Rijzingen

Cornelis L Busink

David B Mason

An elevator for supporting a string of pipe in a well rig is actuable between a closed condition for gripping of the pipe and an open condition, and includes a safety device for preventing opening of the elevator when a string of pipe is positioned in and supported by the elevator, to thus prevent accidental dropping of the string into a well. The elevator may be opened and closed by air pressure, with the safety device preferably including a sensing element positioned to respond to the presence of a well pipe in the elevator at a location to be supported thereby, and a valve actuable by the sensing element to control the delivery of pressure fluid to the elevator.

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Oosterhout, Netherlands

Johannes W Van Rijzingen