Improvements in Automatic Door Closing Apparatus.
Year: 1895

page_text: Date of Application, 11th Oct., 1895-Accepted, 10th Oct., 1896
COMPLETE SPECIFICATION.
Improvements in Automatic Door Closing Apparatus.
I, FREDERIC DOSSOGUE, Engineer, of 7 Rue de la Duchesse, Antwerp,
Kingdom of Belgium do hereby declare the nature of this invention, and in what
manner the same is to be performed to be particularly described in and by the
following statement :-
The present invention relates to automatic door clesing apparatus.
The accompanying drawings represent the improved apparatus.
Fig. 1 is a longitudinal section of the barrel and spring with the spring
uncompressed.
Fig. 2 the same view thereof with spring compressed.
Fig. 3 a view of the piston, spring and rod removed from the barrel.
This invention relates more particularly to the construction of the piston to form
the valve and otherwise to the special form and construction of the piston.
The inner end of rod G is screw-threaded to receive the piston.
The piston is composed of a flexible cup B of leather or any other material with
the form of a truncated cone and of a metallic disk-plate C having the same form
and serving as support for the flexible part B; the border of this disk-plate C
leaves a very small free space between it and the inner wall of the tube K.
A cylinder E is attached to the disk-plate C by means of the bent arms D
perforated at F. This hollow cylinder slids louly in the tube K, it sustains the
disk-plate and guides it centrally in its to and fro movement. Against the end of
cylinder E the end of the helical spring L presses.
The centre of the flexible piece B is maintained against the metallic plate C by
means of a screw-nut I.
The device is attached by its opposite ends at RS respectively to a door and
door-post.
When the door is opened the rod G is drawn out of the tube K, the piston
compresses the helical spring L moving with the inner extremity of the rod G;
the air from in front of the piston passes through the holes F F through the small
space between the inner wall of the tube K and the edge of the disk-plate C,
presses upon the borders of the flexible cup B, bends them and enters the
chamber P which is enlarged by the forward movement of the piston (Fig. 2).
When the door closes again the spiral spring expends and pushes the piston back,
the air in the chamber P is compressed and presses the borders of the flexible cap B
against the wall of the tube K, thus closing the small space formed between this
wall and the edge of the metallic disk-plate C.
As the air is compressed, it retards the movement of the piston, the expansion
of the spiral spring and the movement of the door, while the air escapes through
the passage O controlled by the screw and the mechanisin gradually reverts to
the position shown in Fig. 1.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is:
A door-closing apparatus consisting of an elongated tube having a spring

page_text: throughout its length and provided with a piston forming a valve substantially as
shown in the accompanying drawings and for the purpose set forth.
Dated this 11th day of October 1895.
HERBERT HADDAN & Co.,
18 Buckingham Street, Strand, London, W.C.,
Agents to Applicant.