File:Door closing mechanism Jh. Clay 1896.jpg

From the patent:

Be it known that I, JOHN H. CLAY, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Door Openers and Holders; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in devices for operating large doors of fire-engine houses, gates, and the like, opening the same, and holding them in an open position; and the objects of my improvements are, first, to provide means for swinging doors and gates, &c., open, and, secondly, to construct devices to catch and hold the doors and gates, &c., firmly and rigidly, when set and regulated, at their open limit, and thereby prevent them from swinging and oscillating inward from the desired point or open limit.

I, the copyright holder of this work, hereby publish it under the following license:

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