Abstract: An apparatus and method for facilitating the transfer of pipe sections between a vertical storage array and a power operated pipe elevator. A travelling block is equipped with a measuring arm to position the elevators relative to a pipe stand to be added to the drill string and taken from the storage array by a hydraulically powered pipe transfer device. After insertion of pipe by the transfer device, the elevators are automatically actuated by a contact arm mounted on the elevators. The contact arm signals the actuation of the elevators and withdraws transfer device. Pipe transfer from the storage array to the elevators and back again is semi automatic and under the supervision of the drilling crew.

Abstract: A sensing and sampling system for certain elements capable of assuming a plurality of discrete states including a sensor for sensing the state of each circuit element, and a sampling circuit element for sampling the sensor and for providing signals having a characteristic indicative of the state of the circuit element.