| 摘要 |
A nonresonant acoustic projector especially suited to the creation of low frequency (0-100 Hz, approximately) acoustic signals is provided, this projector including a housing and a rocker arm which is mounted within the housing on a pivotal transverse axis fixed with respect to the housing. At least one piston is sealably mounted in a wall of the housing so that one face of the piston is directed exteriorally and the other face of the piston is directed interiorally with respect to the housing. The inner piston face is connected to a piston push rod which extends perpendicularly to the piston face into the housing, the inner end of this piston push rod being pivotally connected to the rocker arm at a point offset from the rocker arm pivotal axis. A power drive device is connected to the rocker arm at a second offset location for the purpose of rocking the rocker arm in an oscillatory manner about its pivotal axis, wherefore the attached piston push rod forces the piston into reciprocatory movement directed along the axis of the piston push rod. Various power drive devices are described hereinbelow which result in many desirable embodiments of the invention.
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