An electroacoustical transducer is disclosed as incorporating a metallic sing having an aperture located in the wall thereof. A plurality of shutters are rotatably mounted on said housing for effectively and timely opening and closing predetermined portions of said aperture. A plastic support member is disposed within said housing, and a slot is located therein in alignment with said aperture. A wooden frame is disposed in said slot in such manner as to effect a semi-resilient lining therefor, and an electroacoustical energy converter element is disposed within said frame lining. A shutter actuator, either programmed or manually operated, is connected to said plurality of shutters for respectively moving them in such manner as to effect predetermined openings and closings of the aforesaid aperture. A utilization apparatus, such as for example, a sonar transceiver, is connected to the aforesaid energy converter element for energization thereof and for response thereto during transmit and receive modes of operation, respectively.
A flextensional transducer provides a low resonance frequency by having its shell portions connected to its ends by a pin- or rotation-type hinge whereby the motion of the ends of the transducer caused by energization of the transducer drive is transferred to the shell portions by the hinge. The reduction in the resonance frequency is achieved by the shell portions acting as a hinged plate whose ends rotate relative to the transducer ends rather than being cantilevered as in the prior art.
A flextensional electroacoustic transducer with end plates and outwardly convex shells connected to form a housing containing a transduction drive member and laterally disposed tensioning members in contact with said end plates. The tensioning members are connected by hinges allowing rotational oscillatory movement of the end plates with respect to said hinges. Another embodiment includes end plate hinges where the end plates contact the transduction drive member and hinges where the shells connect to the end plates.
A cylindrical transducer for providing an omnidirectional beam pattern in one plane and a line radiation pattern in planes normal to the omnidirectional pattern. The cylindrical transducer active element is a radially poled piezoceramic having a surface into which a square thread is spirally cut so that only a pair of electrical leads are needed to excite the whole assembly. In one embodiment the thread is cut entirely through the thickness of the cylinder and in another embodiment it is cut partially through.
An electroacoustic transducer having one end portion of a first piezoelectric element and one end portion of a second piezoelectric element fixed to a frame such that the first piezoelectric element and the second piezoelectric element are supported by the frame in an opening of the frame in the cantilever manner. A flexible thin film is bonded to the frame and the first and second piezoelectric elements so that it covers at least a gap between each of the piezoelectric elements and the frame. The other end portions of the piezoelectric elements are free end portions, and face each other with a gap therebetween.
A baffle for enlarging the field of view of and enhancing collection of radiation for a sensor apparatus having a transducer for receiving radiation within its field of view. The baffle includes a base securable proximate the transducer, and at least one blade element extending from the base outwardly from the transducer. The base element includes a proximal edge transecting the transducer to establish at least two apertures for the transducer for enlarging its field of view. The blade element is reflective for the radiation to enhance collection of the radiation from a periphery of the enlarged field of view.
