High power,low frequency underwater transducer array

Claim 2

An array of underwater transducers which radiate oppositely directed sound waves, said array comprising a plurality of rigid planar frame structures, each frame defining a surface, means for holding said frames in spaced parallel side-by-side relationship with adjacent ones of said frames being placed in pairs, one member of each of said pairs being positioned in front of the other member of said pair by a distance of approximately a quarter wavelength at the operating frequency, a plurality of said transducers mounted within each of said frame structures with all of the transducers in any of said frames having their radiating surfaces aligned in a single plane and generating sound waves parallel to the surface of said frame, said holding means comprising means for rigidly holding alternate non-adjacent ones of said plurality of said frame structures in spaced parallel planar relationship and for holding nOn-adjacent frames intermediate said alternate frame structures in a second spaced parallel planar relationship, thereby forming two planar groups of non-adjacent frames displaced from each other by said quarter wavelength at the operating frequency.

Claim 3

An array of underwater transducers which radiate oppositely directed sound waves, said array comprising a plurality of rigid planar frame structures, each frame defining a surface, means for holding said frames in spaced parallel side-by-side relationship with adjacent ones of said frames being placed in pairs, one member of each of said pairs being positioned in front of the other member of said pair by a distance of approximately a quarter wavelength at the operating frequency, a plurality of said transducers mounted within each of said frame structures with all of the transducers in any of said frames having their radiating surfaces aligned in a single plane and generating sound waves parallel to the surface of said frame, said holding means comprising means for rigidly holding alternate non-adjacent ones of said plurality of said frame structures in spaced parallel planar relationship and for holding nOn-adjacent frames intermediate said alternate frame structures in a second spaced parallel planar relationship, thereby forming two planar groups of non-adjacent frames displaced from each other by said quarter wavelength at the operating frequency.

Claim 4

An array of underwater transducers which radiate oppositely directed sound waves, said array comprising a plurality of rigid planar frame structures, each frame defining a surface, means for holding said frames in spaced parallel side-by-side relationship with adjacent ones of said frames being placed in pairs, one member of each of said pairs being positioned in front of the other member of said pair by a distance of approximately a quarter wavelength at the operating frequency, a plurality of said transducers mounted within each of said frame structures with all of the transducers in any of said frames having their radiating surfaces aligned in a single plane and generating sound waves parallel to the surface of said frame, said holding means comprising means for rigidly holding alternate non-adjacent ones of said plurality of said frame structures in spaced parallel planar relationship and for holding nOn-adjacent frames intermediate said alternate frame structures in a second spaced parallel planar relationship, thereby forming two planar groups of non-adjacent frames displaced from each other by said quarter wavelength at the operating frequency.

Claim 5

The invention in claim 1 and a source of alternating current electrical power, means for shifting the phase of said electrical power, a first group of said transducers mounted in one group of said frame structures, said first group of transducers being connected directly to said source of alternating electrical power and a second group of said transducers being mounted in the other group of said frame structures, said second group of transducers being connected through said phase shifting means to said source of alternating electrical power whereby said two groups of transducers are driven by electrical currents which are displaced in phase with respect to each other.

Claim 6

The invention in claim 1, characterized in that said parallel spacing between said two groups of transducers is equal to approximately a quarter wavelength of the frequency at which the transducers are operating, and still further characterized in that said phase shifting means introduces a 90* phase shift in said electrical signal of the frequency at which the transducers are operating.

Claim 7

The invention in claim 1 characterized in that said transducers are spherical bidirectional radiators of sound.

Claim 8

The invention in claim 4 and a source of alternating current electrical power, means for shifting the phase of said electrical power, a first group of said transducers mounted in one group of said frame structures, said first group of transducers being connected directly to said source of alternating electrical power and a second group of said transducers being mounted in the other group of said frame structures, said second group of transducers being connected through said phase shifting means to said source of alternating electrical power whereby said two groups of transducers are driven by electrical currents which are displaced in phase with respect to each other.

Claim 9

The invention of claim 5 characterized in that said phase shifting means introduces a 90* phase shift in said electrical signal of the frequency at which the transducers are operating.

Claim 10

An array of underwater transducers comprising a plurality of rigid planar frame structures arranged in spaced parallel side-by-side paired relationship, each of said frames having a plurality of transducers mounted therein with all transducers in each frame being aligned with their radiating surfaces in a single plane, a first group of said transducers and frame structures including a first member of each pair assembled in side-by-side spaced relationship alternating with a second member of each pair also assembled in side-by-side spaced relationship and arranged so that all transducers within said first member group of alternating frame structures lie in a first plane and all transducers within said second member group of alternating frame structures being assembled to lie in a second plane, said second plane of frame structures being displaced parallel with respect to said first plane of frame structures with said displacement being a distance approximately equal to one quarter wavelength at the operating frequency, and the transducers in said second members being positioned to drive into the spaces between said first member frame structures, said second plane being spaced from and parallel to said first plane.

Claim 11

An array of underwater transducers comprising a plurality of rigid planar frame structures arranged in spaced parallel side-by-side paired relationship, each of said frames having a plurality of transducers mounted therein with all transducers in each frame being aligned with their radiating surfaces in a single plane, a first group of said transducers and frame structures including a first member of each pair assembled in side-by-side spaced relationship alternating with a second member of each pair also assembled in side-by-side spaced relationship and arranged so that all transducers within said first member group of alternating frame structures lie in a first plane and all transducers within said second member group of alternating frame structures being assembled to lie in a second plane, said second plane of frame structures being displaced parallel with respect to said first plane of frame structures with said displacement being a distance approximately equal to one quarter wavelength at the operating frequency, and the transducers in said second members being positioned to drive into the spaces between said first member frame structures, said second plane being spaced from and parallel to said first plane.

Claim 12

The invention in claim 7 and a source of alternating current electrical power, means for shifting the phase of said electrical power, said first group of transducers mounted within said first group of frame structures being connected directly to said source of electrical power, and the second group of transducers mounted within said second group of frame structures being connected to said source of alternating current electrical power via said phasE shifting means.

Claim 13

The invention in claim 8 and a reversing switch connected between said source of electrical power and said two spaced parallel groups of transducers whereby the electrical signal phase shifting means may be connected to either of said transducer groups to selectively produce a unidirectional beam of sound from either the front or back of the array assembly.

Claim 14

The invention in claim 7 further characterized in that the width of the assembled frame structures lies in the approximate range of one quarter to one wavelength of the sound generated by the transducers at the operating frequency of the array.

Claim 15

The invention in claim 10 further characterized in that the individual frames in said groups of frame structures are separated by spaces which are approximately equal to the width of said frames.

Claim 16

The invention in claim 7 characterized in that the spacing between said parallel planes is approximately equal to one -quarter wavelength of sound of the frequency at which the transducers are operating, and phase shifting means connected to the transducers in one frame for introducing a 90* phase shift in an alternating current signal of the frequency at which the transducers in said one frame are operating.

Claim 17

The invention in claim 12 and an alternating current electrical power source which includes two alternators connected to a common drive shaft, further characterized in that said phase shifting is accomplished by displacing the rotor of one of said alternators with respect to the rotor of the other alternator so that the phase of a signal generated in one of said alternators is displaced by 90* with respect to the phase of a signal generated in the other of said alternators to produce the displaced phase voltages.