Profile indicator

Claim 1

In a profile indicator for measuring the contour of a surface, said indicator comprising a slide plate, an arm carried by the slide plate, and a stylus attached to one end of the arm, the improvement which comprises a first link bar having a first pivot and a second pivot spaced from the first pivot, said first link being pivotally connected at said first pivot to said slide plate for swinging movement in a plane parallel to said slide plate, a third link bar having a third pivot and a fourth pivot and pivotally connected to said slide plate at said third pivot for swinging movement in a plane parallel to said slide plate, a second link bar having one end pivotally connected to said first link bar at said second pivot, and pivotally connected to said third link bar at said fourth pivot at the point on the second link bar which is spaced from said second pivot, said arm with the stylus being fixed to said second link bar, said first, second, third and fourth pivots, said first, second and third members, and said arm being positioned and configured such that swinging movement of said second link bar results in a compensating swinging movement of said first link bar to cause the tip of the stylus to move in a straight line.