Opening/closing device for manhole cover
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United States of America Patent
Stats
-
Oct 9, 2012
Grant Date -
Apr 23, 2009
app pub date -
Mar 5, 2007
filing date -
May 15, 2006
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
An opening and closing apparatus of a manhole cover has a simple structure and by which opening and closing operation of a cover can be performed safely by a worker alone. An opening and closing apparatus of a manhole cover has such a configuration that the manhole cover is openably and closably coupled to an opening portion of a supporting frame via a rotational joining portion. A hydraulic jack in which a plunger pump is driven by a manual lever raises a ram and the ram lowers due to releasing of an oil returning valve attached on the supporting frame near the rotational joining portion such that the hydraulic jack is rotatable at a lower end portion thereof, and the hydraulic jack and an engagement member fixed attachably to and detachably from the manhole cover are coupled to each other by a pulling member.
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