A coupler for interconnecting spaced bodies in an articulated manner. One form of the coupler includes elongate locking fingers having external locking bosses along opposite ends and supported by a spring in parallel spaced relationship along opposite sides of a pair of elongated spacers. The spacers are movable longitudinally against the spring toward either end of the coupler to allow the locking fingers along the other end of the coupler to be squeezed together for coupling into or uncoupling from a locking recess of one of the spaced bodies. Upon release the spring returns the spacers to neutral aligned positions holding the locking finger in parallel noncompressible coupling relationship. Another form of the coupler includes rotatable spaced latch rings around the locking fingers at opposite ends of the spring. The latch rings have internal release recesses and locking flanges and are each rotatable between a first position at which the spacers are released to move longitudinally relative to the ring and locking fingers and a second position at which the spacers are held against longitudinal movement at neutral positions between the locking fingers holding the locking fingers against compression in coupling positions. Both forms of the coupler are useful for interconnecting a plurality of well tools to form an articulated train of tools for movement through a tubing string.