Abstract: A device for accurately measuring the position of a traveling block in a drilling rig or the like which is supported by means of a cable wrapped around a drum winch assembly. A pneumatic sensor coupled to the drum provides a predetermined number of output pulses per revolution of the drum. During the paying out of a first layer of cable from the drum, the sensor pulses are coupled to a first pneumatic counter, which is preset so as to provide an output pulse corresponding to a predetermined increment of motion during the paying out of the first layer. Additional counters are provided with different preset limits so that they will provide output pulses corresponding to the predetermined increment of motion during the paying out of second and additional layers of cable from the drum. As the cable is paid out or wound in, the output of the drum motion sensor is coupled to the appropriate pneumatic counter by means of a switching assembly.

Abstract: An analog to digital converter device is disclosed. The device includes a plurality of serially connected stages representing bits, each stage including generally a source of current or fluid and a second current or fluid source of opposite polarity, a current or flow direction controlled voltage or pressure drop unit, a comparator unit and a current or flow switch or valve responsive thereto for controlling the source of current or fluid flow.

Abstract: A pneumatic apparatus used for reading punch cards containing processing condition data for articles being processed in an automatic system. The apparatus has a pneumatic reading head for reading the punch cards, and the head has a plurality of air conduits therein. Each conduit has an inlet and an outlet. An air supply is connected to the air conduits for supplying air thereto, and a back pressure detector is provided in each conduit for detecting back pressure therein. The apparatus also includes a movable carrier jig for holding and carrying the article being processed in said system and the jig has a card fitting portion thereon for holding the punch card. The carrier jig is movable toward and away from the conduits so that the card on the card fitting portion can be positioned adjacent the outlets of the conduits.