The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jun. 18, 2002

Filed:

Jul. 30, 1999
Applicant:
Inventors:

James M. Hannan, Portland, OR (US);

Jeffrey S. McMullin, Portland, OR (US);

Assignee:

Credence Systems Corporation, Fremont, CA (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R 3/102 ;
U.S. Cl.
CPC ...
G01R 3/102 ;
Abstract

A docking mechanism docks a test head having a docking plate to a machine having a docking fixture when the docking plate is in a predetermined position with respect to the docking fixture. The test head has cam blocks which are moveable with respect to the docking plate. The docking fixture includes cam followers for engaging cam slots in the cam members when the docking plate is in the predetermined position and the cam blocks are in a first position, so that when the cam blocks are moved to a second position the docking plate and the docking fixture are drawn together. At least two sensors are carried by the docking plate and spaced apart from one another. The sensors cooperate with the docking fixture and are in a first state when the docking plate is not engaged with the docking fixture and the docking plate is being brought towards, but has not attained its predetermined position, and are in a second state when the docking plate attains the predetermined position. A logic function prevents movement of cam blocks from the first position towards the second position when the sensors are in the first state and permits movement of the cam blocks from the first position towards the second position when the sensors are in the second state.


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