Accession Number : ADD016446

Title :   Rebound Hammer.

Descriptive Note : Patent, Filed 19 Jul 93, patented 17 May 94,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Smith, Anthony ; Goff, Dan ; Kruchowy, Roman ; Rhoads, Carl

Report Date : 17 May 1994

Pagination or Media Count : 49

Abstract : A measuring apparatus which detects defects in underwater concrete structures by measuring the compressive strength of the structure. The measuring apparatus comprises a rebound hammer which has extending from the nose thereof a plunger. The plunger is pressed against the structure whose compressive strength is being measured forcing the plunger into the rebound hammer's housing which releases a spring driven mass. A resistive film strip which is in electrical contact with the mass detects the maximum rebound of the mass and provides an electrical signal indicative of this maximum rebound. A data acquisition and processing circuit comprising a microprocessor and signal conditioning electronics receives, processes and stores the electrical signals provided by the resistive strip. This circuit includes a peak detection circuit which captures the peak output signal from the resistive strip.

Descriptors :   *CONCRETE, *HAMMERS, *PLUNGERS, *PATENTS, CIRCUITS, COMPRESSIVE STRENGTH, DATA ACQUISITION, DETECTION, ELECTRONICS, HOUSINGS, MICROPROCESSORS, PROCESSING, RELEASE, SIGNALS, DEFECTS(MATERIALS), UNDERWATER STRUCTURES, STRENGTH(MECHANICS), MEASURING INSTRUMENTS

Subject Categories : Ceramics, Refractories and Glass
      Machinery and Tools

Distribution Statement : APPROVED FOR PUBLIC RELEASE