Probe device usable in measuring stress

Claim 2

For a stress-measuring system, including a readout device, that sends and receives pulsed mechanical waves between two probes in contact with the sample whose stress is being measured, such that the time delay between transmission and reception of such pulses is measured in the readout device, indicating the actual stress present in said sample, a probe device including, in combination, a pair of mutually spaced probes, and means for mounting said probes in mutually spaced relationship, each of said probes including: an electrically conductive contact tip, a piezoelectric crystal having a front surface engaging said contact tip and a rear surface, and a coaxial cable having a central conductor and an electrically conductive coaxial shield circumscribing and insulated from said central conductor, said coaxial shield being electrically grounded, means for electrically coupling said central conductor to said rear surface of said piezoelectric crystal, and electrically conductive means encasing said piezoelectric crystal and the juncture thereof with said central conductor for forming an enlaRged, grounded continuation of said coaxial shield thereabout, said electrically conductive means being coupled electrically to said tip, whereby to be electrically coupled to and between said front surface of said piezoelectric crystal and said coaxial shield, said coaxial shield, electrically conductive encasing means, and contact tip completely shieldingly enclosing said piezoelectric crystal and said central conductor where connected thereto, to electrically shield the same from external interference.

Claim 3

For a stress-measuring system, including a readout device, that sends and receives pulsed mechanical waves between two probes in contact with the sample whose stress is being measured, such that the time delay between transmission and reception of such pulses is measured in the readout device, indicating the actual stress present in said sample, a probe device including, in combination, a pair of mutually spaced probes, and means for mounting said probes in mutually spaced relationship, each of said probes including: an electrically conductive contact tip, a coaxial cable having a central conductor and a coaxial shield circumscribing and insulated from said central conductor, and ultrasonic electromechanical transducer means interposed between and operatively coupled to said central conductor and said contact tip for, as to one probe, converting electrical energy received by its central conductor into mechanical vibration for said probe''s contact tip and, as to the remaining probe, for receiving mechanical vibration from its respective contact tip and converting the same into electrical energy for its respective central conductor, and respective, electrically conductive, shielding means circumscribing said ultrasonic electromechanical transducer and said central conductor and being electrically connected to said respective coaxial shield and also to the tip, said coaxial shield, electrically conductive shielding means, and contact tip completely shieldingly enclosing said piezoelectric crystal and said central conductor where connected thereto, to electrically shield the same from external interference.

Claim 4

For a stress-measuring system, including a readout device, that sends and receives pulsed mechanical waves between two probes in contact with the sample whose stress is being measured, such that the time delay between transmission and reception of such pulses is measured in the readout device, indicating the actual stress present in said sample, a probe device including, in combination, a pair of mutually spaced probes, and means for mounting said probes in mutually spaced relationship, each of said probes including: an electrically conductive contact tip, a coaxial cable having a central conductor and a coaxial shield circumscribing and insulated from said central conductor, and ultrasonic electromechanical transducer means interposed between and operatively coupled to said central conductor and said contact tip for, as to one probe, converting electrical energy received by its central conductor into mechanical vibration for said probe''s contact tip and, as to the remaining probe, for receiving mechanical vibration from its respective contact tip and converting the same into electrical energy for its respective central conductor, and respective, electrically conductive, shielding means circumscribing said ultrasonic electromechanical transducer and said central conductor and being electrically connected to said respective coaxial shield and also to the tip, said coaxial shield, electrically conductive shielding means, and contact tip completely shieldingly enclosing said piezoelectric crystal and said central conductor where connected thereto, to electrically shield the same from external interference.