Wilson Industries, Inc.

Apogee Acoustics, Inc.

Gary E Walker

Leo Spiegel

Harper E Sharp

Richard M Masters

John R Howatt

Elmer J Frey

James L Kirtley, Jr

Anthony J Shuman

The speaker system consists of a single housing containing a tweeter, mid-range and woofer transducer units. The tweeter unit consists of an elongated, aluminum ribbon positioned vertically and connected to the top and bottom of a rigid elongated frame. The ribbon is located between sets of split magnets which are designed to provide a shaped magnetic field that helps center the ribbon in a direction perpendicular to its length. Additional electromagnetic centering is provided by flat ribbon conductors located on the surfaces of the magnets sets which return the current carried by the ribbon. The mid-range transducer is similar to the tweeter transducer in construction except that the edges of the mid-range ribbon are mechanically attached to the frame by foam strips. In addition, the mid-range ribbon is transversely corrugated at variable slant angles relative to ribbon longitudinal axis. The woofer transducer consists of an elongated, trapezoidal, corrugated aluminum ribbon attached to a non-vibrating frame. In order to provide a single electrical path, the ribbon is divided into a serpentine path by a series of cuts. To prevent undesirable auto effects, the ribbon is tensioned in a transverse direction.

Ribbon speaker system

An inertial borehole survey system is disclosed. The survey system of the present invention includes a probe suitable for insertion into a borehole. The probe includes a plurality of temperature sensitive inertial measuring instruments which are utilized to survey the borehole during the descent or ascent of the probe. Accuracy of these instruments is maintained by enclosing the instruments in a thermal insulating package and by providing a mass of isothermal heat absorbing material which exhibits a phase change at a temperature well above most ambient temperatures. In a preferred embodiment of the present invention, a heat absorbing material is utilized which exhibits a phase change at a temperature of 116.degree. F. The probe also includes a longitudinal air passage which permits ambient temperature air to be utilized to cool the isothermal heat absorbing material by passing air through the length of the probe. Currently the instrument cluster is mounted on a member formed of a single billet of metal to form a thermally conductive, small diameter, stiff structure which permits the inertial measurement instruments to be spaced longitudinally in a cluster in order to minimize the diameter to approximately the largest diameter of any single instrument and yet which permits heat generated by the instruments to be absorbed by the heat absorbing material.

Inertial borehole survey system

A system and method for surveying, with accuracies better than one foot per thousand feet of depth, very deep boreholes having the attendant small diameters, high temperatures and high pressures with very high accuracy. A downhole probe is used having a small diameter, less than about four inches. Three linear type accelerometers and at least two gyros to provide three sensitive axes are fixedly mounted at points spaced along the axis of an elongated, rigid, thermally conductive support member to form an instrument cluster. Signals from these instruments are then processed and transmitted serially over a conductor of a conventional wireline to the surface unit where a surface computer continuously computes and records the current position of the instrument.

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Dover, MA, United States of America

Gary E Walker