Charles R Swift

US Patent:

53592522, Oct 25, 1994

Filed:

Mar 30, 1993

Appl. No.:

8/039614

Inventors:

Charles D. Swift - Livermore CA
John W. Bergum - Concord CA

Assignee:

The United States of America as represented by the United States
Department of Energy - Washington DC

International Classification:

H01L 4108

US Classification:

310328

Abstract:

An improved lead magnesium niobate actuator is disclosed comprising a cylindrical lead magnesium niobate crystal stack mounted in a cylindrical casing wherein a bias means, such as one or more belleville washers, is located between one end of the crystal stack and a partially closed end of the casing; and adjustment means are provided which bear against the opposite end of the crystal stack, whereby an adjustable compressive force is constantly applied against the crystal stack, whether the crystal stack is actuated in an extended position, or is in an unactuated contracted position. In a preferred embodiment, cooling ports are provided for the circulation of coolant in the actuator to cool the crystal stack, and provision is made for removal and replacement of the crystal stack without disconnecting the actuator from the external device being actuated.