Stress relief for flextensional transducer

• US 4,420,826 A
• Filed: 07/06/1981
• Issued: 12/13/1983
• Est. Priority Date: 07/06/1981
• Status: Expired due to Term

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Sanders Associates, INC. (BAE Systems Plc)
• Inventors: Marshall, William J. Jr., White, Ronald P.
• Primary Examiner(s): Tudor, Harold J.
• Application Number:
  US06/280,637
• Time in Patent Office: 890 Days
• Field of Search: 310/337, 310/345, 181/110, 181/120, 367/140, 367/141, 367/142, 367/149, 367/153-157, 367/159, 367/163, 367/165, 367/167, 367/111, 367/172, 367/174
• US Class Current: 367/167
• CPC Class Codes: B06B 1/0611 in a pile
• CPC Class Codes: G10K 9/121 Flextensional transducers

Abstract

This invention is a device that permits a flextensional transducer to function after the flextensional transducer experiences a pressure equal to or greater than the pressure found at the survival depth of prior art flextensional transducers. The foregoing is achieved by not bonding at least one end of the transducer'"'"'s piezoelectric stack to the transducer'"'"'s shell and having the other end or ends of the piezoelectric stack held in the vicinity of the transducer'"'"'s shell by a pair of guide rails, etc. This permits the transducer'"'"'s shell to move away from at least one end of the piezoelectric stack at pressures equal to or greater than the pressure at which the stack would experience tensile stresses in a conventional flextensional design. Thus, the piezoelectric stack will not fracture since it receives no tensile stress. Hence, when the transducer experiences a hydrostatic pressure less than the pressure at the survival depth, the shell of the transducer will recontact the free end of the piezoelectric stack permitting the transducer to function.

Claims

1. In an underwater flextensional acoustical transducer comprising a cylindrical shell with an extendable driver stack disposed in an operable position between opposed sides of the shell in a longitudinally prestressed state, the improvement to prevent damage to the driver stack from negative stress resulting from overpressurization of the transducer comprising:

(a) one of the ends of the driver stack being adapted to move longitudinally away from its respective side of the shell during an overpressurization condition of the transducer; and

(b) guide means operably disposed adjacent said end and its respective side for guiding said end back into its operable position as said overpressurization condition is removed.

2. The improvement of claim 1 wherein said guide means comprises:

a pin on one of the two members and a groove on the other adapted to receive said pin in a sliding relationship.

3. The improvement of claim 1 wherein said guide means comprises:

guide rails carried by the shell extending along the driver adjacent said end.

4. The improvement of claim 3 wherein:

said end and said guide rails are tapered inwardly.

5. The improvement of claim 1 wherein said guide means comprises:

an elastic calking material having a soft rubber-like quality disposed adjacent said end and its respective side.