Head clamp releasable locking device

A device for positioning a surgical head clamp, relative to a base, comprising a plurality of arms each having a longitudinal axis and opposite ends, with a first arm being connectable to the base, an intermediate second arm being connected between an end of said first arm and an end of a third arm with said arms connected so as to be pivotable about an end of the adjacent arm, at least one arm including a locking lever to lock the associated arm against pivoting relative to the adjacent arm,

• said third arm having a free end and including a spherical member carried in a socket and comprising an integrally formed mounting tube extending radially outwardly of said spherical member, said mounting tube being positionable at a selected point relative to the axis of said arm through, said third arm including a gripping device to restrain movement of said spherical member in said socket,
• said head clamp including a mounting post insertable into said mounting tube and having a plurality of recesses spaced about the surface of said post adjacent one end thereof, said mounting tube including a releasable locking device for engaging and holding said mounting post against rotation and withdrawal from said mounting tube so that accidental release of the mounting post is prevented.