Vacuum cup with precision hard stop

摘要

A method and apparatus for holding a part on a fixture in a precisely known predetermined position includes pressing a surface of the part against a vacuum head (25) and sealing an annular elastomeric sealing ring against the part surface. A valve button (108) of a valve is engaged by the part surface to open the valve and establish communication between a vacuum source. The part is pulled by the vacuum against a hard stop (90) in the vacuum head (25) having a fixed precisely known relationship to said vacuum head reference surface. The hard-stop (90) can be mounted in the base of the vacuum head for pivoting about at least one axis to self-align the hard-stop face (94) with the part face.