Rotatable holder with position memory

Claim 1

A position memorizing mechanism for establishing and memorizing the angular orientation of a rotatable part with respect to a fixed part of a holder for an article, the mechanism comprising: a relatively fixed part, having a front side; a stop defined on the front side of the fixed part; a relatively rotatable part having a rear side; means supporting the rear side of the rotatable part at the front side of the fixed part and enabling relative rotation of the rotatable part with respect to the fixed part; a first engagement surface on the rear side of the rotatable part, a cooperating second engagement surface on the front side of the fixed part, and the first and second engagement surfaces being engageable for locking the rotatable part against rotation with respect to the fixed part when the fixed and rotatable parts are secured together; securing means between the fixed and the rotatable parts for drawing them together for moving the first and second engagement surfaces into engagement and also for enabling the fixed and rotatable parts to move slightly apart for disengaging the first and second engagement surfaces; a rearwardly projecting protrusion on the rotatable part, the protrusion including third engagement surface thereon, the third engagement surface having a first smaller diameter section spaced further away from the rear side of the rotatable part, the protrusion having a second greater diameter section spaced further toward the rear side of the rotatable part; memory means supported at the rotatable part including a fourth engagement surface on the periphery of the memory means engageable with the third engagement surface of the protrusion, the fourth engagement surface having a diameter such that it engages the third engagement surface when the memory means is at the first small diameter section of the third engagement surface and such that it disengages from the third engagement surface when the memory means is at the second greater diameter section of the protrusion with the third and fourth engagement surfaces in engagement while the securing means is adjusted to move the first and second engagement surfaces apart from engaging one another, the memory means is rotatable with respect to the fixed part while the memory means fourth engagement surface is in engagement with the rotatable part third engagement surface such that the memory means rotates together with the rotary part; the securing means being further releasable to also release the engagement between the third and fourth engagement surfaces; stop engagement means on the memory means for engaging the stop on the fixed part when the memory means is rotated to an orientation at which the stop engaging means engages the stop, and the memory means being rotatable with respect to the fixed part for the stop engagement means to be off the stop.