Two-axis, self-nulling skin friction balance

摘要

A skin friction force measuring device having a first pivoted 13 L-shaped arm 12, a second arm 16 pivoted 17 on one end of the L-shaped arm with a sensing element 20 attached to an end of the second arm. In response to skin friction forces on the sensing element 20 the arms are pivoted about the two pivots and two nulling means 23, 28 force the pivots back to their zero positions. The outputs of the two nulling means are indicative of the skin friction forces along two perpendicular axes, x and y, in the plane of the sensing element.