GB766984A - Improvements in and relating to the transmission of ultrasonic vibrations - Google Patents

Abstract

766,984. Ultrasonic inspection devices. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Feb. 20, 1953 [Nov. 21, 1951], No. 27326/51. Class 118 (2). [Also in Group XXXIX] The coupling (see Group XXXIX) connecting an ultrasonic transducer, e.g. piezo-electric, to a solid body, enables the angle at which vibrations are received from or sent into the body to be varied without movement of the member engaging the solid body. The transducer is mounted on a pad 14 on the cylindrical surface of a wedge 13 slidable on a bolster 12 contacting the solid body 11. The bolster 12 is clamped in position by a bracket 38 bearing on studs 21 in the bolster. Plates 29 secured to the bolster 12 carry spring-loaded rollers 36 running on flanges on the .wedge 13 and a manuallyrotatable pinion 32 which engages a rack 33 on the wedge 13 to slide the wedge 13 over the bolster 12. The pad 14 which is spring-urged against the wedge 13 is secured with play to arms 26 on a pivot 17 on members 18 fixed to the wedge 13. Links 19 pivoted on the studs 21 have slots to receive the ends of the pivot 17 and pins 25 threaded into the pad 14. In order to compensate for changing distance between the transducer and the body 11 when the position of the wedge is adjusted, it is arranged that movement of the pin 25 in the slot in the arm 19 controls an electronic delay device governing the start of the time base sweep of a cathode-ray tube indicator. In a modification a second wedge similar but at right angles to the first is adjustably mounted on the pad 14 and a second pad carrying the transducer co-operates with the second wedge. The second wedge projects through slots in the arms 26 and links 19 and its movement is controlled in a similar manner to that of the first wedge, but the links are pivoted to the pad 14 instead of the bolster 12. It is stated that information derived from a scanning movement of the transducer may be displayed in a similar manner to that employed for radar. Further, that scanning by orthogonal or spiral movements can be used and the results presented on a cathode-ray tube in amplitude or intensity modulated form. Also that since films of oil are necessary between the sliding parts, intermittent scanning movements with application of pressure to the sliding parts when stationary is desirable, bursts of high pressure oil being fed through ducts in the parts to free the sliding surfaces when about to be moved. Specifications 766,982 and 766,983, [Group XXXIX], are referred to.