Proving rings offer excellent primary and secondary calibration standards for the calibration and measurement of force parameters up to 1,00,000 pound of force. These rings have extremely low uncertainty and high-resolution capability. Morehouse proving rings are produced according to the designed specification originally established by the nist, u.S.A. These rings are regulated according to the stringent and exacting standards of astm. Proving rings are based on the principle of the steel load ring to guarantee maximum reliability through years of use. A steel ring of the proper alloy, carefully devised and machined, will perform as a near-perfect elastic member. When forces are applied to the ring, its diameter changes according to the load. The load applied can be measured by a precise measurement of the change in diameter. . In each morehouse proving ring, the measuring apparatus that is designed into it performs consistently within related limits. In order to smooth the progress of calibration, proving rings are fitted with an electrical reed vibrator, a dial revolution counter, a vernier index, a carbide micrometer contact to minimize wear and a ball seat in the top boss.
