Clutch for pivoting workpiece support

A workpiece support, comprising:

• (a) a base;
• (b) a platform;
• and
• (c) an adjustment mechanism coupled between the base and the platform to selectively enable pivoting of the platform relative to the base, the adjustment mechanism comprising:
• (i) a rotatable member coupled in a fixed position relative to one of the base and the platform, the rotatable member configured to rotate within a rotational plane and about an axis of rotation, the rotatable member including an annular engagement surface circumscribing the axis of rotation;
• (ii) a housing coupled in a fixed position relative to the other of the base and the platform, the housing having defined thereon a convergent surface opposing the annular surface of the rotatable member and separated therefrom by a gap that decreases between first and second positions within the rotational plane of the rotatable member;
• (iii) a roller disposed within the gap between the convergent and annular surfaces, the roller configured to rotate about an axis of rotation that is parallel to the axis of rotation of the rotatable member, and the roller having a diameter that is less than the gap between the convergent and annular surfaces proximate the first position, but is greater than or equal to the gap between the convergent and annular surfaces proximate the second position;
• (iv) a biasing mechanism coupled to the roller and configured to bias the roller toward the second position to wedge the roller between the convergent and annular surfaces and thereby restrict rotation of the rotatable member;
• and
• (v) a release mechanism coupled to the roller and configured to selectively oppose the biasing mechanism to bias the roller toward the first position and permit rotation of the rotatable member to pivot the work surface relative to the base.