AN IMPROVED DOOR CHECK AND SPRING
Year: 1885

page_text: We SAMUEL PICKERING and WILLIAM PICKERING, Mill Furnishers and JOHN
EDWARD NORTON Joiner, all of Ironmonger Lane Brunswick Street Oldham in
the County of Lancaster do hereby declare the nature of our invention for
AN IMPROVED DOOR CHECK AND SPRING" and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
"
This invention relates to that class of door spring which consists of a swinging
air cylinder provided with a spring piston.
Our object has been to construct a double action spring which shall act silently;
close the door gently and not allow it to swing violently to and fro until the spring
stops but to stop it as soon as it is closed and hold it steadily in this closed position
against the action of the highest wind, and thus our apparatus is especially
applicable to heavy swing doors for public buildings hotels, and other places.
It is aleo so constructed that it can be examined, adjusted and repaired without
disturbing the flooring or cement in which the casing is fixed.
In order that our invention may be clearly understood we have annexed hereto
a sheet of drawings and have marked the same with figures and letters of reference
corresponding with those in the following explanation thereof.
Fig. 1. is a plan view of our improved door chest with the top plate removed.
Fig. 2. is a horizontal section.
Fig. 3. a longitudinal section and
Fig. 4. a transverse section through about the line A. B on Fig. 1. and showing
the position of the cam hereafter described when the door is opened and the
cylinder and spring piston have assumed the position shown by dotted lines on
Fig. 1.
a is the casing of the apparatus b and b¹ the top plates or covers thereof,
c is the swinging cylinder and d the spring piston; the door is formed with a
squared recess to receive the square end e¹ of a vertical pivot e, e' upon which is
cast or otherwise fixed a cam f, f.
The cam ff is attached to the spindle d', d of the spring piston d by the pin g
forming a pivotal joint and the end of the cylinder c, c furthest from the cam ƒ, ƒ
swings upon a hinge h, h attached to or forming part of one end of the casing a, a.
The cam ff is provided beneath with a circular or annular double incline i, i see
Figs. 3 and 4 and the casing a, a is so formed or fitted as to contain two spring
catches k, kor bolts immediately beneath and bearing up against the said incline
so that when the door is in its closed position (see Figs. 1. 2. and 3) it is held
there by these catches or both k, k springing up into the notches ** of the double
incline i, i.
The piston d, d is provided with a small air valve z of suitable construction so
that when the door is opened and the cam pulls the piston up the cylinder c, c as
shown dotted at Fig. 1, the air can escape. through the valve which however closes

page_text: .
again when the cylinder returns, and the air is forced through an outlet air
valve, of ordinary construction placed at or near the end c¹, c¹ of the cylinder c, c.
The rapidity of the return movement of the door is regulated by adjusting the
valve to allow the air to escape more or less quickly; m, m is the spring which
closes the door. The casing a, a is let in to the flooring or cement so that the
covers b, bare flush with the surface, the part b of the cover, closes over the carn
and the pivot of the door, the part 6¹ may be mounted on hinges, so that the
cylinder and working parts can be readily inspected adjusted or repaired when
required.
The action of the apparatus is as follows:-When the door is pushed open the
cam ff overcomes the pressure of the spring bolts i, i and revolves with the action
of the door, pulling the spindle and the piston d with it and swinging the
cylinder c, c either to the right or to the left. This compresses the spring m, m.
The door can be opened until a projection n, n on the cam f,f comes against a
suitable stop as at o, o on the cross plate p, p.
When the door is released the spring m, m expands and forces the piston d, d
back into the cylinder c, c; the air however between the said piston d, d and the
end c¹, c¹ of the cylinder forms a cushion and prevents the door from closing too
violently.
As the air escapes through the valve l, the piston gradually returns in the
cylinder and pulls back the spindle and the cam and consequently slowly closes the
door. The cylinder resumes its central position and the spring. bolts i, i will then
hold the door in the closed position resisting the side pressure of any ordinary
wind that may blow against it.
It is evident that as the cylinder c, c can swing either to the right or to the left
and the incline on the cam f, f is double, the door spring is a double acting one,
that is to say the door can be opened either inwards or outwards.
The apparatus also being in the casing and let in to the flooring or cement is
entirely out of sight and is thus a great improvement upon the other pneumatic
spring door checks which have hitherto been usually fixed either to the door or
the frame and which are very unsightly whereas our invention may be applied to
the most ornamental doors without in any way spoiling their design or general
appearance.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we.claim is.
First. An air cylinder arranged in a casing beneath the door so that it can swing
either way and allow the door to open inwards or outwards in combination with a
spring piston connected to the door by a cam and pivot or their equivalents
substantially as herein before described.
Secondly. The combination with a spring piston d and swinging air cylinder c
constructed substantially as described, of the cam f provided with inclines, notches,
and spring catches or bolta.
Thirdly. The combination with a spring piston d and swinging cylinder c of the
cam provided with the projection n which is arrested by the stop o, o and limits
the action or opening of the door.