Abstract: A flattened resilient sheet metal band prestressed to assume the shape of an extended tubular rod when unstressed, is stored as a coil wound on a spool. The end of the band is fixed to a post. When the coil is released, the band assumes its tubular shape and the end of the band fixed to the post encircles the post. A clamp responsive to the change in shape of end of the band clamps it to the post when the band assumes its tubular rod shape.

Abstract: A rotor mounting a sensor to be inserted into the earth is rotatably mounted within and locked to a cylindrical housing. The latter may be dropped to the earth and may come to rest in any orientation. When at rest, the rotor is unlocked and a drive mechanism rotates the rotor with respect to the housing. Gravity causes a ball in a tortuous path in the rotor to traverse the path and to drop into one of a plurality of annularly spaced recesses in the housing when the rotor reaches a desired orientation. With the ball in place in a recess, a wedge surface on the rotor wedges against a portion of the ball extending from the recess and this stops the rotor--in the desired orientation.