330-PS-6457-2:   Master Caption:   U.S. Navy Studies Effects of Vibrations On Man.   To study the effects of mechanical vibrations on man, the U.S. Navy has designed and constructed a research instrument termed a large displacement amplitude vibration machine.   The Naval Research Laboratory, cooperating with the Naval Medical Research Institute, Bethesda, Maryland, has completed the first phase of the project by the construction, calibration, and testing of the instrument.  Over five years in the building, the instrument has now been assembled and installed at the Naval Medical Research Institute where research studies are being undertaken by Lieutenant Commander David E. Goldman, MC, USN, (a Biophysicist).  The two-ton instrument was designed to study low frequency vibrations.  It is capable of producing smooth vibrations from two to 50 cycles per second.   Constructed to handle loads of up to 200 pounds, the table-top vibrating platform moves vertically through a maximum of four inches at accelerations up to 15 units of gravity.  Also, special built-in features allow the investigators to vary the cycles per second and the amplitude while the instrument is in operation, or to hold one and vary the other.   As machinery with greater power concentrations is developed, the effects of vibration on operators and maintenance crews become more important.   Aviators, operators of heavy construction equipment, operators of pneumatic tools, and of small-hand operated rills, buffing tools, etc., often complain of fatigue and discomfort.  Occasionally, there is interference with vision and the ability to perform fine handwork.  Little is known at this time as to just what effects vibration has on body tissue.  Since the body is very complicated mechanical system, the problem is extremely difficult.  The investigators in their studies up to this time have found that different parts of the body respond maximally at different speeds.  Studies are now underway to map the mechanical structure of the body and its vibratory motion at various settings of the vibration machine.  Studies will then be made of physiological and psychological responses.  With this information, it will be possible to establish safety and tolerance limits as well as to devise protective measures when indicated.   Subject is shown on vibration platform.     Photograph released January 19, 1954.  (4/14/2015).
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