Patent ID: 7392588

Claim:
A rotary encoder, comprising: a first component group including a detector system; and a second component group including: a code disk; a shaft having a central bore hole, a shoulder and a ridge having an outer surface; a ring element having an inner surface and an actuation device; and a component arranged between the outer surface and the inner surface of the ring element; wherein the first component group and the second component group are rotatable relative to each other about an axis; wherein the detector system is configured to scan the code disk to determine a relative angular position between the two component groups with respect to each other; wherein points on the inner surface of the ring element and points on the outer surface of the shaft having different distances with respect to the axis such that, via the actuation device, the ring element rests on the shoulder, a force having a radial directional component acts on the ridge via the component, and a machine part inserted into the bore hole of the shaft is clampable.