Patent ID: 6871522

Claim:
A continuous extrusion machine having a chassis ( 1 ) supporting a wheel ( 2 ) for rotation and a shoe ( 3 ) enveloping a span of the periphery of the wheel ( 2 ) and co-operating with a groove ( 7 ) formed in the periphery of the wheel ( 2 ) to form a passage, a support mechanism supporting at least one of said shoe ( 3 ) and said wheel ( 2 ) to be relatively displaceable in a direction perpendicular to the axis of rotation of the wheel ( 2 ) during use, a gap sensor system able to sense the size of a gap ( 12 ) between the wheel periphery and the shoe ( 3 ) when the machine is operating, and a control device responsive to the gap sensor system to adjust the support mechanism to displace the shoe ( 3 ) relative to the wheel ( 2 ), in each of two mutually perpendicular directions whereby the size and shape of the gap can be controlled.