Sagittally amplified piezoelectric actuator

• US 4,318,023 A
• Filed: 02/21/1980
• Issued: 03/02/1982
• Est. Priority Date: 02/21/1980
• Status: Expired due to Term

• Current Assignee: Physics International Company
• Original Assignee: Physics International Company
• Inventors: O'Neill, Cormac G., Smiley, Parker C.
• Primary Examiner(s): Budd, Mark O.
• Application Number:
  US06/123,215
• Time in Patent Office: 740 Days
• Field of Search: 310/328, 310/321, 179/110 A
• US Class Current: 310/328
• CPC Class Codes: H02N 2/043 Mechanical transmission means, e.g. for stroke amplification

Abstract

An electroexpansive linear actuator utilizes a sagittal tension member to amplify linear motion in which the electroexpansive member is placed in compression between a fixed base support and a lever support member hingedly connected to the fixed base. One end of the sagittal tension member is attached to the fixed base while the other end is attached to the lever support member distal the hinge point. The device to be actuated is connected proximate the midpoint of the sagittal tension member and moves perpendicular to the longitudinal axis of the sagittal tension member when the electroexpansive member expands and contracts. A second embodiment of the actuator utilizes a second lever support arm instead of the fixed base as a bearing support for the other end of the electroexpansive member.

Claims

1. An electroexpansive actuator comprising

a sagittal tension member having a first end and a second end comprising an elongated resilient strap deformed proximate its midpoint to cause said ends extending longitudinally from each side of said midpoint to define an obtuse angle,

an electroexpansive member having a first end and a second end adapted to exert a tensile force in said sagittal tension member coincident with the longitudinal axis of said sagittal tension member,

means for connecting said first end of said electroexpansive member to said first end of said sagittal tension member, said means comprising

a fixed support member,

a lever arm support member having first and second ends,

means for connecting said first end of said sagittal tension member to said first end of said lever arm member, and

means for hingedly connecting said second end of said lever arm member to said fixed support member, said means comprising

at least one wire having one end attached to said second end of said lever arm and the other end of said wire connected to said fixed support member,

means for connecting said second end of said electroexpansive member to said second end of said sagittal tension member,

means for applying a voltage to said electroexpansive member for varying the dimensions thereof, and

means for operating a device connected proximate the midpoint of said sagittal tension member.

2. An electroexpansive actuator comprising

a fixed base support,

a lever arm member,

means for hingedly connecting said lever arm member adjacent said means for hingedly connecting said lever arm member to said fixed base support and adapted to amplify the motion of said electroexpansive member by rotating said lever arm member about said means for hingedly connecting said lever arm to said fixed base support,

a sagittal tension member defining an obtuse angle having one end connected to said fixed base and the other end connected proximate the end of said lever arm member distal said means for hingedly connecting said lever arm member to said fixed base support, whereby rotation of said lever arm about said means for hingedly connecting said lever arm to said fixed base support creates tension in said sagittal tension member in a direction coincident with the longitudinal axis of said sagittal tension member,

means for operating a device connected to said sagittal tension member proximate the midpoint thereof, and

means for applying a voltage to said electroexpansive member to increase and decrease the longitudinal dimension thereof.

3. An electroexpansive actuator comprising

a rigid base support,

a sagittal tension member generally defining a loop of flexible material having one side connected to said base support,

a pair of first and second lever arm members disposed proximate opposite ends within said looped sagittal tension member,

an electroexpansive member having one end bearing in compression against said first lever arm member and the other end bearing in compression against said second lever arm member,

means for operating a device connected to said sagittal tension member proximate the midpoint thereof between said first and second lever arm members distal said rigid base support, and

means for applying a voltage to said electroexpansive member whereby said electroexpansive member changes length between said first and second lever arm members when a voltage is applied to said electroexpansive member.