Patent ID: 7561785

Claim:
A lock mechanism for a stage apparatus, comprising: a movable stage which is provided on a stationary member movable in a reference plane; a pair of engaging members provided on said movable stage; a pair of lock members which are positioned between said engaging members and are movable so as to engage and disengage with corresponding said engaging members, said lock members being movable along a straight imaginary line passing through said engaging members; a first link member which is movable in a plane parallel to said reference plane in a direction along a reference straight line which passes through a central position of pair of said engaging members and is orthogonal to the moving direction of said lock members; a pair of second link members symmetrically arranged with respect to said reference straight line, wherein one end of each of said second link members is rotatably mounted on said first link member via a first rotational axis, and the other end of each of said second link members is rotatably mounted on a corresponding said lock member via a second rotational axis, said first and second rotational axes extending normal to said reference plane; a lock driving device which moves said lock members to an engaged position wherein said lock members mutually move away from each other and engage with said corresponding engaging members by moving said first link member in one direction along said reference straight line; and an unlock driving device which moves said lock members to a disengaged position wherein said lock members mutually move toward each other so as to disengage with said corresponding engaging members by moving said first link member in the other direction along said reference straight line.