The theory and practice of modern framed structures : designed for the use of schools, and for engineers in professional practice (1897)
Johnson, J. B. (John Butler), 1850-1902, Bryan, C. W. (Charles Walter), 1863-1927, Turneaure, Frederick Eugene, 1886- · New York : J. Wiley & Sons · leaf 405
Fig. 395. In this form of end lift the bridge is first swung into line and latched ; then, by turningthe vertical shaft A, the wheels B revolve about their centres, and at the same time force thesuspended wheels W under the ends of the arms. Let Fig. 396 represent the motion of the parts of the end… … Fig. 396. R the maximum lift has been attained. Then the total work done in raising the end = ~ h. 2 As the time for opening or closing a swing bridge is usually limited, let t equal thenumb.er of seconds required to raise the ends; then the mean power required to raise the ends ^RXh 2t * See Plate…
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