A transducer for the non-destructive testing of plate bonds (particularly adhesive bonds)

摘要

949,501. Piezo-electric crystal holders. KONINKLIJKE NEDERLANDSE VLIEGTUIGENFABRIEK FOKKER N.V. June 17, 1960 [May 13, 1960], No. 21435/60. Heading H1E. [Also in Division H4] An electro-mechanical transducer (particularly for testing the shearing strength of bonds between plates) comprises a barium titanate disc 2 provided with mutually insulated and metallized electrodes 5, 6, and holding means for the disc consisting of a metal pin 3 engaging the interior end face of the disc and a spring 4, the cylindrical surface of the disc having longitudinal grooves 7 terminating above its interior end face and co-operating with some play with the end pieces 8 of metal strips 9. Electrode 6 continues to the lower ends of grooves 7. It is stated that radial disc vibrations are substantially undamped.