Improvements in Pneumatic Door Checks and Closers.
Year: 1895

page_text: Date of Application, 21st May, 1895-Accepted, 27th July, 1895
COMPLETE SPECIFICATION.
Improvements in Pneumatic Door Checks and Closers.
I, JOHN SCHRACK SHRAWDER, a citizen of the United States, residing at
Collegeville, in the County of Montgomery and State of Pennsylvania, Doctor of
Medicine, do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement :-
My invention has relation to a pneumatic door check and closer operating by
means of a piston working in a cylinder; and it relates more particularly to the
construction and arrangement of such an appliance.
The principal objects of my invention are first, to provide a pneumatic door
check and closer in which the parts are subjected to only a limited pressure or
strain; and second, to provide a pneumatic door check and closer with means and
mechanism, whereby atmospheric pressure or weight is utilized as the means for
checking the closing movements of a door actuated thereto by spring door closing
mechanism.
My invention consists in connecting said mechanism with a pneumatic device,
comprising a cylinder having open and closed ends, a valve chamber connected
with the head and opening into the cylinder, check and relief valves therein and a
piston and its rod, whose normal position, that is, when the door is closed, is near
the open end of the cylinder, so that the opening movement of the door will thrust-
the piston towards the closed end of the cylinder, thus exhausting the air therein
through the valved chambers thereof, whereupon in the reverse action of the
piston, caused by the closing movement of the door, a partial vacuum will be
created in the cylinder behind the piston while its movement towards its normal
position and consequently the movement of the door, will be checked by
atmospheric pressure on the outer surface thereof, the force of the spring, and
expansion of the remaining quantity of air in the cylinder being so regulated as to
finally overcome the said pressure and close the door.
The nature and general features of my present invention will be more fully
understood from the following. description taken in connection with the
accompanying drawings forming part hereof; and in which
Figure 1, is a top or plan view of a pneumatic door check and closer embodying
features of my invention in application to a door and the jamb thereof.
Fig. 2, is a view partly in section and partly in elevation of the head of the
cylinder of the check and closer provided with a valve chamber and check and
relief valves seated or mounted therein.
Fig. 3, is a perspective view of the check and closer of my invention, comprising
a cylinder having open and closed ends with a valve chamber in the closed end
having check and relief valves and a piston with its rod, whose normal position.
as shown with the door closed, is near the open end of the cylinder, and also
showing the spring door closing mechanism.
Fig. 4, is a similar view, showing the normal position of the parts of the check
in connection with a door and the jamb thereof looking at the device from the rear
and also showing the door in a closed position; and
Fig. 5, is a similar view of the check and closer of my invention, showing the
position of the several parts thereof, when the door is open, and such being. its
position as illustrated therein.

page_text: The
Referring to the drawings A, is a door hinged to the jamb, casing or
framework A', thereof. B, is a cylinder having the head closed, and provided
with a cylindrical projection forming a valve chamber 61, which is pro-
vided with transverse channels or chambers 2 and 3, whereof one has a split
screw 3, and whereof the other has a perforated dish-shaped seat 6º, detachably
engaged by a plug valve 612, and which is prevented from escaping from the channel
or chamber 6, by means of a cross-pin 68, inserted through the same.
chamber 6, is provided with the channels or chambers 62 and 6, and with the
split screw 63, and plug 612, constitute the check and relief valves of the cylinder B.
The cylindrical projection 61, of the head of the cylinder B, is provided with an
integral lug 6, in movable connection with a bifurcated bracket or casting F, by
means of a pin or pivot 610, and the said bracket or casting is adapted to be secured
to the door A, by means of screws or the like 6. The opposite end b, of the
cylinder is open as clearly illustrated in the drawings.
C, is the piston of the cylinder B, afforded a range of to and fro movement
therein. The piston is provided with a flanged gasket or packing ring c, and a
stem c¹. At the rear end of the stem c¹, is provided a bearing e, which is engaged
by the bolt or pin c, of a cross-arm c, formed preferably integral with a lever-
arm. It may be here remarked that the connection of the piston stem c¹, with
the lever-arm co, is at or beyond the centre of the same considered with respect to
the length of said arm, as clearly illustrated in Figs. 3 and 4. At the forward end
of the lever-arm c, by means of a pivot or pin d, and a bifurcated strap d¹, is
movably connected an extensible arm e, which latter is pivotally connected with the
forked end of a bracket el, adapted to be secured to the jamb A¹, of the door by
means of screws or the like e². The rear end of the lever-arm c, is connected by
means of a screw or bolt with a bracket G, which is secured to the door A,
by means of screws g', as clearly illustrated in Figs. 1, 3 and 4. Coiled around the
hub of a ratchet or toothed wheel I, is a leaf spring. H, one end of which is
secured thereto and the other end to a back-stop or post i, of the bracket G,
whereby in the manipulation of the door A, to open it the spring H, will be
compressed so that when the energy exerted upon the door in the opening thereof,
is relieved the latter will be automatically returned to initial or closed position.
The tooth or ratchet wheel I, is loosely mounted on the bolt g, extending through
the bearing of the lever-arm c, and bracket G. Engaging through one of the
openings 2, in said wheel 1, is a pin 3, to permit of the said wheel, which has one
extremity of the coiled spring H, connected therewith, being manipulated so as to
increase the tension of the spring H, by inserting the pin 3, through the said
lever-arm c, and an opening 2, of the wheel I, after having turned by hand or
otherwise, the said spring one or more times around to closely compact the leaves
to each other as clearly illustrated in Fig. 1, of the drawings.
The mode of operation of the pneumatic door check and closer of my invention
as hereinbefore explained, is as follows:-
The door check and closer with its accessories will be in the position shown in
Figs. 1, 3 and 4, when the door A, is closed.
To open the door A, the piston C, is forced from its position at or near the open
end b, of the cylinder B, in the direction of the head or closed end thereof, thus
exhausting the air therein through the valve chamber b', by its lifting the plug
valve, from its perforated or apertured seat 6, in the transverse channel or
chamber ³, of the valve chamber 6, and thereby escaping from the cylinder B.
In the reverse action of the piston C, within the cylinder B, caused by the closing
movement of the door, a partial vacuum will be created in the cylinder, behind the
piston, while the movement towards its normal position is at or near the open end b,
of the cylinder B, and consequently the movement of the door A, will be checked
by atmospheric pressure on the outer surface of the piston C, and the force of the
spring H. and expansion of the remaining quantity of air in the cylinder B, are so
regulated as finally to overcome said pressure and to close the door. It may be
here remarked that by adjusting the split-screw 63, in its seat in the valve

page_text: chamber 6, of the cylinder B, the rapidity of the closing movement of the door,
under the influence of the forces acting upon and against the device, can be
regulated to a nicety, as practice has demonstrated.
It will be manifestly obvious that as to minor details, modifications may be made
without departing from the spirit of my invention, and hence I do not wish to be
understood as limiting myself to the precise construction and arrangement of all
the parts of the device as illustrated; but
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:—
1. A pneumatic door check and closer, comprising a cylinder having open and
closed ends, a valve chamber connected with the head of said cylinder and opening
into the cylinder and check and relief valves, a piston and its rod, the normal
position of which when the door is closed is at or near the open end of said
cylinder and spring door closing mechanism operatively connected with the said
rod and said door and the jamb thereof, substantially as and for the purposes.
described.
2. A pneumatic door check and closer, comprising a cylinder having open and
closed ends, a valve chamber connected with the head of said cylinder and opening
into the cylinder, movable check and detachable relief valves therein, said cylinder
adapted to be pivotally attached to a door, a piston and its rod, the normal position
of which piston when the door is closed is at or near the open end of said cylinder,
a spring controlled lever-arm connected with said rod and an extensible arm
connected with said lever-arm and the jamb of a door, substantially as and for the
purposes described.
Dated at Philadelphia. P. this 15th day of Faher AD 1895.
JOHN SCHRACK SHRAWDER,
Per J. G. Lorrain, M. Inst. E.E., M. Inst. M.E.,
Chartered Patent Agent.