(1) Field of the Invention
This invention relates to a mechanism for picking up and placing on a substrate small articles such as micro-electronic components. 
(2) Summary of the Prior Art
In the processing of micro-electronic components (chips), the component is obtained from a supply source and transported to a placement head having a placement mechanism which picks up the component and places it on a printed circuit board.  In commonly owned U.S. patent application Ser.  No.  299,979 filed Sept. 8, 1981 such a component processing apparatus is disclosed.  Also disclosed in commonly owned U.S. patent application Ser.  No.  565,749 filed Dec. 27, 1983 there is a mechanism for adjusting the position of the placement head for different sized components.  In both of the above disclosures, the placement head performs a motion on a vertical axis from the position of receiving the component to positioning the component on the printed circuit board. 
There are machines for automatically obtaining chip size components from a supply source and transporting the component to a placement head which positions the component on a printed circuit board.  Examples of these machines are illustrated in U.S. Pat.  Nos.  4,307,832; 4,327,482; 4,346,514 and 4,393,579.  None of these machines have a placement mechanism with a vertical motion on a single axis during which the mechanism picks up the component and moves the component down to the board for positioning between the conductive lands of the circuit on the board.  Further, the placement mechanisms are not rotationally positionable on the same axis to align the component with the circuit on the board.