Resonant acoustic transducer system for a well drilling string

Claim 1

A transducer for coupling acoustic signals to a bore-hole drilling string primarily during drilling operations comprising: piezoelectric means having an electrical capacity C, a first mechanical axis, and adapted for compression and elongation along said first mechanical axis when excited by a variable electric field disposed thereacross, inductor means having inductance L and coupled in series relation with said piezoelectric means in an electrical circuit having an electrical resonant frequency substantially determined by C and L, fastener means for affixing said piezoelectric means against a surface of said bore-hole drilling string and for holding said piezoelectric means in substantially fixed compression, spring means having mass m, spring constant k, and a compression axis collinear with said first axis, extending from and coupled integrally with said fastener means, and elongate cylindrical mass means having mass M, a cylinder axis collinear with said first axis, and extending from and coupled integrally with said spring means to form a mechanical vibrating circuit having a mechanical resonant frequency that is substantially determined by m, k, and M to be substantially equal to said electrical resonant frequency.