Abstract
The friction of wedge sliders on rubber depends surprisingly little on the angle between their leading faces and the rubber surface. Friction remains moderate even when this angle is 90°. A simple theory is put forward which accounts qualitatively for the observed limitation of the frictional force and which also predicts an experimentally verified lift of the sliders. In agreement with these findings, a photoelastic investigation of the stress distribution around the sliders reveals that no ramming pressure precedes them in the rubber. The absence of a ramming pressure is attributed to a forward tilt of the rubber which originates from the couple of the frictional force with respect to the undeformed rubber underneath.
