Acoustic transducer

Claim 2

An improved electroacoustical transducer for detecting sound energy in a liquid transmission medium comprising: a first cylindrical mass having a peripheral surface in acoustic contact with said transmission medium and arranged to be accelerated in directions substantially at right angles to the longitudinal axis of said cylindrical mass by impingement of said sound energy upon said surface, the planes of said surface being parallel to said longitudinal axis, a first piezoelectric shear type element having a first shearing portion secured to said first mass for accelerating said element in response to acceleration of said first mass, said element having a poling direction substantially at right angles to the longitudinal axis of said first cylindrical mass, a second mass shielded from said sound energy and fastened to a second shearing portion of said piezoelectric element and providing inertia so that a shearing force is set up in said piezoelectric element in response to acceleration of said first mass, and electrodes coupled to said piezoelectric element for deriving an electrical signal therefrom; said second mass being surrounded by said first mass and so positioned that it is isolated from direct acceleration by said sound energy; further comprising a second piezoelectric shear type element fastened to said first and second masses, said first and second piezoelectric elements having poling directions disposed in parallel planes and oriented at substantially 90* with respect to each other.

Claim 3

An improved electroacoustical transducer for detecting sound energy in a liquid transmission medium comprising: a first mass having a peripheral surface in acoustic contact with said transmission medium and arranged to be accelerated in directions substantially at right angles to the longitudinal axis of said mass by impingement of said sound energy upon said surface, the planes of said surface being parallel to said longituDinal axis, a first piezoelectric shear type element having a first shearing portion secured to said first mass for accelerating said element in response to acceleration of said first mass, said element having a poling direction substantially at right angles to the longitudinal axis of said first mass, a second mass shielded from said sound energy and fastened to a second shearing portion of said piezoelectric element and providing inertia so that a shearing force is set up in said piezoelectric element in response to acceleration of said first mass, electrodes coupled to said piezoelectric element for deriving an electrical signal therefrom, and further comprising a second piezoelectric shear type element fastened to said first and second masses, said first and second piezoelectric elements having poling directions in parallel planes and oriented at different angles with respect to each other.

Claim 4

An improved electroacoustical transducer for detecting sound energy in a liquid transmission medium comprising: a first mass having a peripheral surface in acoustic contact with said transmission medium and arranged to be accelerated in directions substantially at right angles to the longitudinal axis of said mass by impingement of said sound energy upon said surface, the planes of said surface being parallel to said longituDinal axis, a first piezoelectric shear type element having a first shearing portion secured to said first mass for accelerating said element in response to acceleration of said first mass, said element having a poling direction substantially at right angles to the longitudinal axis of said first mass, a second mass shielded from said sound energy and fastened to a second shearing portion of said piezoelectric element and providing inertia so that a shearing force is set up in said piezoelectric element in response to acceleration of said first mass, electrodes coupled to said piezoelectric element for deriving an electrical signal therefrom, and further comprising a second piezoelectric shear type element fastened to said first and second masses, said first and second piezoelectric elements having poling directions in parallel planes and oriented at different angles with respect to each other.

Claim 5

An improved hydrophone comprising: a first mass of material, a first piezoelectric shear-type element having one active surface fastened to said first mass, a second mass of material fastened to another active surface of said piezoelectric element, said first mass surrounding at least a portion of said second mass and said piezoelectric element so that impinging sound energy accelerates said first mass only to set up stresses in said piezoelectric element and so that said piezoelectric element produces a voltage which varies as a function of said stresses, and a second piezoelectric shear-type element having one active surface fastened to said first mass and having another active surface fastened to said second mass so that impinging sound energy accelerates said first mass to set up stresses in said second piezoelectric element, and so that said second piezoelectric element produces a voltage which varies as a function of said stresses, said first and second piezoelectric elements have their poling directions lying in parallel planes but extending at right angles with respect to each other.

Claim 6

An improved hydrophone comprising: a first mass of material, a first piezoelectric shear-type element having one active surface fastened to said first mass, a second mass of material fastened to another active surface of said piezoelectric element, said first mass surrounding at least a portion of said second mass and said piezoelectric element so that impinging sound energy accelerates said first mass only to set up stresses in said piezoelectric element and so that said piezoelectric element produces a voltage which varies as a function of said stresses, and a second piezoelectric shear-type element having one active surface fastened to said first mass and having another active surface fastened to said second mass so that impinging sound energy accelerates said first mass to set up stresses in said second piezoelectric element, and so that said second piezoelectric element produces a voltage which varies as a function of said stresses, said first and second piezoelectric elements have their poling directions lying in parallel planes but extending at right angles with respect to each other.

Claim 7

An improved hydrophone comprising: a cylindrically shaped inner mass concentrically positioned along a longitudinal axis, a first piezoelectric shear-type element having one active face operatively fastened to one end of said inner mass and symmetrically positioned relative to said longitudinal axis, a second piezoelectric shear-type element having one active face operatively fastened to the other end of said inner mass and symmetrically positioned relative to said longitudinal axis, said first and second piezoelectric elements having poling directions disposed in planes that are substantially parallel to each other, a hollow outer mass positioned around said inner mass and said first and second piezoelectric elements and spaced from said inner mass, said outer mass being symmetrically positioned relative to said longitudinal axis and being fastened to respective second active faces of said first and second piezoelectric elements so that acceleration of said outer mass in a direction lateral to said axis creates shearing stresses in said first and second piezoelectric elements, means connected to said first and second piezoelectric elements deriving electrical signals therefrom, third and fourth piezoelectric shear-type elements respectively operatively secured between said first and second piezoelectric elements and said outer mass, said third and fourth piezoelectric elements having poling directions disposed in planes parallel to the planes of the poling direction of said first and second piezoelectric elements extending in a first direction and those of said third and fourth piezoelectric elements extending in a second direction.

Claim 8

An improved hydrophone comprising: a cylindrically shaped inner mass concentrically positioned along a longitudinal axis, a first piezoelectric shear-type element having one active face operatively fastened to one end of said inner mass and symmetrically positioned relative to said longitudinal axis, a second piezoelectric shear-type element having one active face operatively fastened to the other end of said inner mass and symmetrically positioned relative to said longitudinal axis, said first and second piezoelectric elements having poling directions disposed in planes that are substantially parallel to each other, a hollow outer mass positioned around said inner mass and said first and second piezoelectric elements and spaced from said inner mass, said outer mass being symmetrically positioned relative to said longitudinal axis and being fastened to respective second active faces of said first and second piezoelectric elements so that acceleration of said outer mass in a direction lateral to said axis creates shearing stresses in said first and second piezoelectric elements, means connected to said first and second piezoelectric elements deriving electrical signals therefrom, third and fourth piezoelectric shear-type elements respectively operatively secured between said first and second piezoelectric elements and said outer mass, said third and fourth piezoelectric elements having poling directions disposed in planes parallel to the planes of the poling direction of said first and second piezoelectric elements extending in a first direction and those of said third and fourth piezoelectric elements extending in a second direction.

Claim 9

An improved hydrophone comprising: a cylindrically shaped inner mass concentrically positioned along a longitudinal axis, a first piezoelectric shear-type element having one active face operatively fastened to one end of said inner mass and symmetrically positioned relative to said longitudinal axis, a second piezoelectric shear-type element having oNe active face operatively fastened to the other end of said inner mass and symmetrically positioned relative to said longitudinal axis, a hollow outer mass positioned around said inner mass and said first and second piezoelectric elements and spaced from said inner mass, said outer mass being symmetrically positioned relative to said longitudinal axis and being fastened to respective second active faces of said first and second piezoelectric elements so that acceleration of said outer mass in a direction lateral to said axis creates shearing stresses in said first and second piezoelectric elements, means connected to said first and second piezoelectric elements deriving electrical signals therefrom, wherein said first and second piezoelectric elements having poling directions that lie in parallel planes but that are positioned at an angle with respect to each other.

Claim 10

An improved hydrophone comprising: a cylindrically shaped inner mass concentrically positioned along a longitudinal axis, a first piezoelectric shear-type element having one active face operatively fastened to one end of said inner mass and symmetrically positioned relative to said longitudinal axis, a second piezoelectric shear-type element having oNe active face operatively fastened to the other end of said inner mass and symmetrically positioned relative to said longitudinal axis, a hollow outer mass positioned around said inner mass and said first and second piezoelectric elements and spaced from said inner mass, said outer mass being symmetrically positioned relative to said longitudinal axis and being fastened to respective second active faces of said first and second piezoelectric elements so that acceleration of said outer mass in a direction lateral to said axis creates shearing stresses in said first and second piezoelectric elements, means connected to said first and second piezoelectric elements deriving electrical signals therefrom, wherein said first and second piezoelectric elements having poling directions that lie in parallel planes but that are positioned at an angle with respect to each other.