Swing-bridge.
A swivel-bridge, spanning a canal or dock entrance, and opening horizontally to allow a vessel to pass.
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Swing-bridge. |
It was invented by Nicolas Bourgeois for the ditch of the Tuileries.
His reward was a pension of 1,200 livres per annum.
Draw or
swing bridges are required over dock entrances, canals, or other navigable waters, to allow the passage of vessels with standing masts.
The
swing-bridge is balanced, and rotates in a horizontal plane.
It is usually in two sections, each of which, when opened, is landed on its won side of the dock, the extended ends of the two meeting in the middle when brought into line, and affording a bridge across the water-course.
The tail of the bridge at the
St. Katharine's docks,
London, works around 240°; the clear opening between the walls is 44 feet 9 inches; the rise in the middle is 3 feet. The turning is effected by a wheel, running horizontally on a number of rollers that run upon a circular cast-iron bed. It is worked by a winch and pinion operating on a segment-rack.
The bridge is well balanced, and easily swung upon its central pivot by a single attendant.
A,
Fig. 6121, is an elevation;
B, a plan;
C, an enlarged view of the circular bed.
A swing-bridge on a large scale was constructed on the Great Western Railway of
Ireland, to cross the entrance to Lough Atalia.
It has two spans of 60 feet each, and is balanced on a central pier of 34 feet diameter.
See
Humber, “On iron bridges.”
Fig. 6122 is the iron swing-bridge over the entrance-lock to the
West India Docks,
London.
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Swing-bridge, London dock entrance. |
Plate XLI., page 1721, is a view of a swing-bridge on the Amsterdam,
Utrecht, and Cologne Railway where it crosses the Yssel, near Westervoort,
Holland.
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Fig. 6123 is a view of the swing section of the
Mississippi bridge at
Keokuk, Iowa.