Abstract: A ratchet wrench mechanism is set forth. It is constructed so that it advances on rotation in one direction and locks when attempting to rotate the ratchet in the opposite direction. It does not require incremental advances as occur with a toothed locking mechanism in the ratchet. Rather, the handle supports a socket which has a surrounding shoulder with upper and lower faces. The socket and shoulder have a gap to permit socket insertion over a bolt. The shoulder passes through wedge shaped chambers or cavities in the housing, and wedges loaded by a bias spring are forced towards the narrow end of the tapered chambers. Rotation in one direction is permitted because the wedges are retracted to the large end of the cavity, but rotation in the opposite direction is forbidden when the wedges move to the opposite and narrow end of the cavity.

Abstract: A ratchet wrench mechanism is set forth. It is constructed so that it advances on rotation in one direction and locks when attempting to rotate the ratchet in the opposite direction. It does not require incremental advances as occur with a toothed locking mechanism in the ratchet. Rather, the handle supports a socket which has a surrounding shoulder with upper and lower faces. The socket and shoulder have a gap to permit socket insertion over a bolt. The shoulder passes through wedge shaped chambers or cavities in the housing, and wedges loaded by a bias spring are forced towards the narrow end of the tapered chambers. Rotation in one direction is permitted because the wedges are retracted to the large end of the cavity, but rotation in the opposite direction is forbidden when the wedges move to the opposite and narrow end of the cavity.

Abstract: A seawater probe for measuring a physical parameter which includes a sensor element having an electrical characteristic dependent on the parameter and a detector circuit for deriving a measurement signal corresponding to a measured value of the electrical characteristic, the improvement including a reference element having a known, stable value of the electrical characteristic connected in series with the sensor element, the reference and sensor elements being powered by a single power supply, means for selectively connecting the sensor and reference elements separately in the detector circuit, and means for calibrating the detector circuit using the known value of the electrical characteristic of the reference element and the measurement signal derived when the reference element is in the detector circuit.