Abstract: An improved linkage assembly (10) provides for locking the pivotable position of one member (12) relative to another member (14). The linkage assembly permits the unlocking of these members, their subsequent repositioning, and the reliable relocking in a desired position without utilizing tooling. The first member (12) includes a pair of spaced apart support flanges (24,26) each having a through aperture (28) therein defining a flange female spline (29). The second member (14) has an end (42) positioned between the pair of support flanges (24,26) and also includes a through aperture (46 ) defining a pair of second member female splines (47). A pair of control members (84,86) are each slidably moveable along the common axis (32) and extend through the respective flanges (24,26). Each control member (84,86) has a male splined portion (66) which normally engages both the respective flange female spline and the second member female spline to lock the rotatable position of the first and second members.