Abstract: The present invention instrument measures the differential distances between two adjacent surfaces. To accomplish this end, the instrument has a main body to which there is pivotally coupled a U frame whose arms extend at an angle from its base, so that as the former is pivoted in one direction, the latter will correspondingly pivot in an opposite direction. Contact points are provided to the arms and the bottom surface of the body, and the base of the U frame is biased by a spring loaded slidable element within the body which in turn is connected to a transducer. Thus, as the instrument is moved between two adjacent surfaces, the lower and upper contacts having previously been adjusted to maintain contact with the respective lower and upper surfaces, any deviation in the space between the two being measured adjacent surfaces would cause the U frame to pivotally move.

Abstract: The adjustable measuring parallel has a head assembly that includes upper and lower slider blocks that are mated to each other at an incline, which may be a common transversal incline. The upper slider block is connected to a movable extender rod member which has connected to its other end a ferromagnetic core. The lower slider block is connected to a stationary extender member which is threaded to a handle that has a cavity in which a linear variable differential transformer (LVDT) is fitted. By moving the movable extender member in directions along the longitudinal axis of the instrument, the upper slider block is forced against the lower slider block such that relative movements are effected between the two slider blocks along a direction orthogonal to the parallel surfaces of the slider blocks, or the longitudinal axis of the tool.