Patent ID: 7421988

Claim:
A positive-guidance apparatus for conversion of a rotary movement of a drive to a reciprocating movement of a part, the apparatus comprising: a first cam having formed thereon a first cam area disposed to directly push the part away from a given position resting against the first cam; a flexible element having an end connected to the part; and a second cam having formed thereon a second cam area disposed to interact with said flexible element to pull the part back solely by way of said flexible element into the given position resting against the first cam; and wherein: said first and second cam areas have mutually different contours; a contour of said second cam area is outside of a contour of said first cam area; said second cam area is formed on said second cam in the form of a sleeve and an internal contour corresponds to the contour of the first cam area; and said cam element has a first cam having a holding area formed thereon axially alongside said first cam area, having the same contour as the first cam area, and having said second cam with said second cam area disposed thereon.