Built 1880 - King Iron Bridge Company
The Bridge Street Bridge was constructed in 1880 by the King Iron Bridge Company of Cleveland Ohio. It survives as a unique example of a small late 19th century hand operated mechanical drawbridge. The lifting system dates back to drawbridge designs used during the middle ages. The bascule span is lifted by steel chains attached to the far corners at one end, with the other ends of the chains wrapped around constant diameter drums or sheaves. Counterweights are hung by chains at the towers, which wrap around variable diameter drums so that each successive wrapping is smaller. The counterweight drums and the lifting chain drums are mounted on a common shaft. As the diameter of the counter weight drums gets smaller the mechanical advantage of the counter weight decreases. In this way, as the bascule span opens the mechanical advantage needed from the counter weights continues to decrease. This is a unique characteristic of the Bridge Street Bridge. It is unknown if any other bridges are in existence today that contain a similar mechanism. The bridge was operated by a hand crank at the base of the tower, which was connected to the counterweight and lifting shaft through a gear and pulley system. This system allowed the bridge to be opened and closed by hand with a relatively constant effort.| HM Number | HM1TI7 |
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| Tags | |
| Year Placed | 2009 |
| Placed By | Rockland County Highway Department |
| Marker Condition | No reports yet |
| Date Added | Saturday, August 6th, 2016 at 9:01am PDT -07:00 |
| UTM (WGS84 Datum) | 18T E 591109 N 4543487 |
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| Decimal Degrees | 41.03751667, -73.91606667 |
| Degrees and Decimal Minutes | N 41° 2.251', W 73° 54.964' |
| Degrees, Minutes and Seconds | 41° 2' 15.06" N, 73° 54' 57.84" W |
| Driving Directions | Google Maps |
| Area Code(s) | 845, 914 |
| Closest Postal Address | At or near Bridge St, Piermont NY 10968, US |
| Alternative Maps | Google Maps, MapQuest, Bing Maps, Yahoo Maps, MSR Maps, OpenCycleMap, MyTopo Maps, OpenStreetMap |
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