Appletons' cyclopaedia of applied mechanics: a dictionary of mechanical engineering and the mechanical arts (1880)
D. Appleton and Company, Benjamin, Park, 1849-1922 · New York, D. Appleton · leaf 316
closed, however, unlocking can be effected by the movement of either one of the dials indepen-dently of the other since the yoke will not support the lever and block if either of its supports beremoved. It thus follows that the lock cannot lock up unless both movements are in good order andare…
Mechanical engineering -- Dictionaries
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