IMPROVEMENTS IN FLOOR SPRINGS OR APPARATUS EMPLOYED FOR CLOSING DOORS."
Year: 1881

page_text: LETTERS PATENT to Edward Bull, of Halifax, in the County of York, Civil
Engineer, for an Invention of "IMPROVEMENTS IN FLOOR SPRINGS OR
APPARATUS EMPLOYED FOR CLOSING DOORS."
PROVISIONAL SPECIFICATION left by the said Edward Bull at the Office
of the Commissioners of Patents on the 1st January 1881.
EDWARD BULL, of Halifax, in the County of York, Civil Engineer.
"IMPROVEMENTS IN FLOOR SPRINGS OR APPARATUS EMPLOYED FOR CLOSING
DOORS."
This Invention relates to that class of door spring which is inserted within the
floor, and the improvements consist in the employment of a short lever connected
to the bottom of the door by means of a pivot and screw or other suitable means.
On the underside of the lever a socket or half round hole is formed, fitting onto
a stationary ball, which allows the lever to swing backward and forward thereon as
the door is opened or closed, a hole being made in the lever for lubricating the
socket joint. To the lever one end of a chain is attached, the other end of the
chain being attached to a collar by a link, the chain being always extended or
kept in a state of tension by a spiral spring acting against the collar and a fixed
part of the box or framework surrounding the apparatus. The chain passes
between two friction rollers, against one or other of which it bears on the door
being opened.
When putting this apparatus together, the chain is first attached to the collar,
and when the other end of the chain has to be attached to the said lever it is
necessary for the spiral spring to be compressed so as to leave the end of the chain
slack; for this purpose a bolt and nut is employed, which compresses the spring
until the chain is connected to the lever.
On the nut being unscrewed the spring is free to act between the collar and
bottom of the box. In order to ensure the door to swing back into a straight
line, a flat spring is employed acting against a pulley fixed on the underside of
the lever.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Bull in the Great Seal Patent Office on the 30th June
1881.
EDWARD BULL, of Halifax, in the County of York, Civil Engineer.
"IMPROVEMENTS IN FLOOR SPRINGS OR APPARATUS EMPLOYED FOR CLOSING
DOORS,"
This Invention relates to that class of door spring which is inserted within the
floor, and in order that the Invention may be better understood, I will proceed to
describe the accompanying Sheet of Drawings illustrative thereof, wherein Fig. 1 is
sectional elevation shewing the spring and door closed; Fig. 2 is plan of same.
with the cover or top plate removed to shew the parts of the apparatus more
clearly. The apparatus consists of a box or casing A having a moveable cover B;
C is a lever with a boss or pivot D formed thereon, which is inserted within the
bottom of the door for the door to rest and ride upon; E is a stationary ball fitting
into a socket or half round hole formed in the lever C, so that the said lever with
the weight of the door upon it can freely swing backward and forward, a suitable
hole being made in the lever for lubricating the socket joint. The lever C is
connected by chain F and link G to one end of the spiral spring H, the other end
of the spring being secured to the stationary fixing I, which is capable of
adjustment by screw J, the head K of the screw being held in its place by the
flanges L. The chain passes between two friction rollers M, against one or other
of which it bears when the door is opened. To ensure, when the door is closed,
that it shall stop and remain as near as possible in a straight line or at right angles
with the door jamb, a spring or springs N is provided indented in the middle, for
the purpose of receiving the end of the lever C. It will be seen that when the
door is opened either backward or forward, the lever C will be moved as shewn in
dotted lines in the plans, Figs. 2 and 4, consequently the chain will be pulled and
the spring opened, but immediately the door is released and at liberty the spiral
spring will close and shut the door.
Instead of employing closed springs which are opened by the opening of the
door, open springs may be employed, which are closed by the opening of the door,
so that when the door is set at liberty the spring will distend itself and thereby
close the door. This form of spring is shewn in Figs. 3 and 4.
When putting the apparatus together as shewn in Figs. 3 and 4, the chain is
first attached to the spring by link G, and when the other end of the chain has to
be attached to the lever C, it is necessary for the spiral spring to be compressed so as
to leave the end of the chain slack; for this purpose the screw J and nut K is
employed, which on being turned in one direction compresses the spring so that
the chain can be connected to the lever. On the nut being unscrewed the spring
is free to act between the stationary fixing I and bottom of the box.
Having thus described the nature and particulars of my Invention, and shewn
by Drawings how the same is to be performed and carried into practice, I would
have it understood that I do not confine myself to the exact details of the parts
herein shewn and described, as some of them may be varied without departing
from the peculiar features of the Invention, but what I claim is,—-
Firstly. The combined use of the lever C, chain F, and spiral spring H,
substantially as herein shewn and described.

page_text: Secondly. The general combination and arrangement of the parts, substantially
as herein shewn and described, for closing doors.
In witness whereof, I, the said Edward Bull, have hereunto set my hand
and seal, this Twenty seventh day of June, in the year of our Lord One
thousand eight hundred and eighty one.
EDW. BULL.
BULL. (L.S.)