Operatory stool with adjustable arm

Claim 1

An operatory stool comprising in combination, a seat, support means for said seat depending therefrom, a post extending upward from said seat adjacent an edge thereof, and a curved arm supported by the upper end of said post within a plane transverse to said post, the improvement comprising a post section reciprocably mounted upon the upper portion of said post for vertical movement in opposite directions and the upper end of said post section being connected to said arm to support it, coengageable rotation control members including a circular member coaxial with the axis of said post and provided with a series of radial recesses in the upper end thereof and a pin member extending transversely through said post section and positionable selectively in one or more of said recesses to prevent relative rotational movement between said circular member and post section about the axis of said circular member when said pin member and one of said recesses are coengaged, a cylindrical housing fixedly connected to the lower surface of said curved arm and enclosing said circular member and pin, and spring means within said housing and interengageable between said pin member and circular member and operable normally to urge said members into coengagement to prevent relative rotation between said post and arm, whereby when said arm is moved upward a predetermined distance said member with recesses and said pin member are disengaged to permit rotation of said arm about said post and upon release of said arm said spring means is operable to assist gravity in restoring said members into coengagement.