Door Spring
UNITED STATES PATENT OFFICE.
THOMAS THORPE, OF WEST CAMBRIDGE, MASSACHUSETTS.
DOOR-SPRING.
Specification of Letters Patent No. 506, dated December 7, 1837.
To all whom it may concern:
Be it known that I, THOMAS THORPE, of West Cambridge, county of Middlesex, and State of Massachusetts, have invented a new and useful Improvement in Door-Springs. The said improvement, the principle thereof, and modes in which I have contemplated the application of the same, together with such parts, combinations, or characteristics by which it may be distinguished from other inventions, and which I claim I have fully set forth in the following specification and drawings referred to herein.
A. A represents the outer casing of brass, or other suitable metal, shaped as seen in the drawings, or otherwise properly formed.
B is the door on which the spring is to be fastened; C, the door frame.
E is a metallic rod, turning on a hinge at a, in the side of the piece of metal F, screwed to the door frame. The rod E passes through holes in the ends b, c of the casing A, moving freely back and forth in said holes.
G is a cross bar, attached to the rod E in a proper manner, and has connected to each extremity the end of a wound spring, H H, whose opposite end is confined to the end b of the casing, or to a pin d, passing through the sides thereof.
When the door is opened, the spring H H are extended by the movement of the rod E through the slots in the ends b, c of the casing, and on withdrawing the force applied to open the door, the springs contract, and immediately close the same.
Instead of two springs, I may use only one, or I may employ three or more, should it be deemed advisable.
The main advantage of this spring consists in the exertion of a strong force to close the door, when nearly shut. Other kinds of door spring generally fail in this part of their operation.
I claim as my improvement-
The above arrangement of springs acting on a rod E, and operating in manner above described.
In testimony that the above is a true description of my said invention, I have hereto set my hand this ninth day of November, in the year eighteen hundred and thirty seven.
THOMAS THORPE.
Witnesses:
R. H. EDDY,
A. E. WILSON.