Valve machining unit

Abstract

Methods and apparatus for on-site machining are disclosed. The internal portions of devices such as turbine valves must be machined in place, but present certain areas, such as the valve seat, that cannot be readily accessed from an external surface. The present invention provides methods and apparatus whereby such surfaces can be machined using a fixture to which a milling head or other machine tool is attached. In a preferred embodiment, a mounting plate is provided that contains holes or other features that cooperate with the structure to which the plate attached, thereby providing a rigid base for the machining operation. The present inventions also preferably uses a tool bar that has a cutting head that retracts and swivels. In its initial position the cutting head is swiveled inside the tool bar and the assembly can be inserted into a structure. Once inside, a threaded push rod is turned and manipulated to cause the cutting head to swivel, and then it is locked in place. After machining is complete, the cutting head is unlocked, swiveled and retracted into its original position so that the tool bar can be removed.

Dependencies are inferred from the claim text.