Collinson Manhole Cover for Boilers, Patent Model

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This model was submitted to the U.S. Patent Office with the application for the patent issued to Henry Collinson, Boston, Massachusetts, April 13, 1875, no. 161934.
The invention consists of a lid or cover with a true flat face arranged in such a manner that while being forced home against a flat seat it receives a sliding and rotating motion thereon.
The model represents an opening in a plate around which is formed a flat plane face, which forms a seat for the dish –shaped lid or cover. A curved bar of metal spans the opening over the cover and supports a threaded nut through which passes a T-handled screw by which the cover is forced against the seat. At the inner end of the screw is an eccentric head that fits in a recess in the center of the cover, so that turning the screw forces the cover against the seat and moves the center of the cover in a circle, while the friction causes the cover to rotate somewhat about its own center. The result is a combined sliding and rotating of the cover as it is forced against the seat.
This description comes from the 1939 Catalog of the Mechanical Collections of the Division of Engineering United States Museum Bulletin 173 by Frank A. Taylor.
Currently not on view
date made
patent date
Collinson, Henry
place made
United States: Massachusetts
associated place
United States: Massachusetts, Boston
Physical Description
brass (overall material)
overall: 4 1/4 in x 5 1/2 in x 4 3/8 in; 10.795 cm x 13.97 cm x 11.1125 cm
ID Number
accession number
catalog number
patent number
See more items in
Work and Industry: Mechanical and Civil Engineering
Industry & Manufacturing
Bulletin 173
Engineering, Building, and Architecture
Data Source
National Museum of American History


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