AN IMPROVED DOOR CHECK
Year: 1885

page_text: I ANDREW MACKIE, of 42 Cambridge Street Westminster in the County of
Middlesex Civil Engineer do hereby declare the nature of my invention for AN
IMPROVED DOOR CHECK to be as follows :-
A. Cylinder with an open front and a closed back end is attached to the door
frame or other convenient position and a piston is fastened to the door in such a
manner that when the door is in the act of closing and within a short distance of
the door frame the piston enters the cylinder and compresses the air, bringing the
door gently up almost to a standstill the door then gently closes altogether as the
air within the cylinder escapes past the piston or thro' a small orifice either in
the piston or in the cylinder-A small flap valve opening inwards is fixed in the
piston or cylinder so as to admit air freely when the piston is drawn out by the
door being opened-to facilitate the re-entry of the piston when the door is closing
the cylinder is made slightly bellmouthed. The cylinder & piston can be fixed the
reverse to that described above or in any other suitable relative positions.
I ANDREW MACKIE of 42 Cambridge Street Pimlico London in the County of
Middlesex, Engineer, do hereby declare the nature of my invention for A DOOR
CHECK and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:
The door check is preferred to be constructed as shown on the drawing, and
consists of a curved cylinder "a" closed at one end and open at the other, the
closed end being provided with a base for securing the cylinder to the door frame.

page_text: A piston "b" is attached to the door "d" by means of a bent bracket "c" in
such a manner and at such a distance from the door hinge "e" that the piston ""
describes an arc equal to the curve of the cylinder "a."
**
The cylinder "a" is curved to a radius described from the hinge of the door "e
and the open end is bell mouthed to facilitate the entry of the piston "b."
,
"
The piston "b" is preferred to be made a close but not a tight fit in the
cylinder "a" and without an air inlet valve so as to prevent the door being pushed
open too suddenly as well as to prevent the door slamming when closing.
.
The relative positions of the parts can be changed the piston being on the top of
the door frame, while the cylinder is on the door, their attachments being altered
to suit.
The action of the arrangement is as follows, a resistance to opening is caused by
a partial vacuum formed behind the piston on its outward stroke and a resistance
to slamming is caused by the air in the cylinder being suddenly compressed by the
entry of the piston, the door slowly closing as the air escapes past the piston or
through a small aperture.
When the arrangement is only required to prevent the door slamming a small
air inlet valve is fixed in the cylinder or piston so as to admit air behind the piston
on its outward stroke, the air valve closing on the inward stroke of the piston and
so causing the air to be compressed as before described.
Any suitable material can be used in the construction of the various parts.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
1st The used of a Cylinder curved or bent to a radius as shown on the drawing.
2ndly The use of a close fitting piston without an air inlet valve for the purpose
described.
3rd The arrangement of a piston & cylinder in which the piston leaves the
cylinder entirely when the door is opened to a sufficient extent.
.
4th The arrangement described and shown on the drawings with or without an
air inlet valve.
It is however to be clearly understood that I do not claim the air inlet valve as
forming part of the invention.
Dated this 26th day of October 1885