IMPROVEMENTS IN DOOR CLOSING OR CHECK APPARATUS FOR THE PREVENTION
Year: 1885

page_text: Prevention of Slamming.
I, CHARLES HIGGIN MAXSTED, of Westholme, in the town and county of
Lancaster, Silk Spinner, do hereby declare the nature of said invention for
"IMPROVEMENTS IN DOOR CLOSING OR CHECK APPARATUS FOR THE PREVENTION
OF SLAMMING to be as follows:-
This invention consists in an arrangement of weight and cord apparatus for
closing the door and in employing in combination therewith a pneumatic cushioning
device consisting of an air cylinder arranged in such manner that the compression
of air within the cylinder and its escape therefrom may cause the motion of the
door when pulled to by the weight to be partially arrested when nearly closed but
so as that the door may perform the remaining portion of the closing operation
more freely and with greater certainty than in arrangements of such apparatus
heretofore known to me.
According to my invention the air cylinder is arranged horizontally and is
mounted at one end on a hinge joint or pivot secured to the frame or jamb a little
above the door. When the door is closed the cylinder occupies a position nearly
parallel thereto. A regulating valve of the usual or any convenient kind for the
escape of the compressed air is provided. The piston preferably consists of a
washer of leather pressed into the hollow or concave side of a piston block by the
head of a fastening screw this arrangement permitting the air to pass round the
edge of the leather washer during the outward movement of the piston but pro-
viding an air-tight piston ring on its return or inward movement. The piston rod
emerges from the free end of the cylinder and is jointed to the extremity of a short
projecting arm secured to the door. From this arm a cord passes over suitably
placed pulleys to a weight hanging preferably on one side out of the way. It will
be obvious that the pull or power exerted by the weight upon the door will be
uniform throughout its entire opening and closing traverse.
By arranging the air cylinder as above described the door when wide open,
hat is to say at about right angles to its position when closed, exerts its greatest
ID 21

page_text: thrust or power upon the piston such power gradually decreasing as the door
travels radially to its closing point. Thus the closing of the door by the action of
the weight will cause the air within the cylinder to be compressed and the
cushioning or arresting effect to be produced at a point determined by the adjust-
ment of the regulating valve; the remaining portion of the closing operation being
performed when the thrust upon the piston and its resisting power are nearly
exhausted.

page_text: Prevention of Slamming.
I, CHARLES HIGGIN MAXSTED, of Westbolme, in the town and county of
Lancaster, Silk Spinner, 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:-
This invention consists in an arrangement of weight and cord apparatus for
closing the door and in employing in combination therewith a pneumatic cushioning
device consisting of an air cylinder arranged in such manner that the compression
of air within the cylinder and its escape therefrom may cause the motion of the
door when pulled to by the weight to be partially arrested when nearly closed but
so as that the door may perform the remaining portion of the closing operation
more freely and with greater certainty than in arrangements of such apparatus
heretofore known to me.
According to my invention the air cylinder is arranged horizontally and is
mounted at one end on a hinge joint or pivot secured to the frame or jamb a little
above the door. When the door is closed the cylinder occupies a position nearly
parallel thereto. A regulating valve of the usual or any convenient kind for the
escape of the compressed air is provided. The piston preferably consists of a
washer of leather pressed into the hollow or concave side of a piston block by the
head of a fastening screw, this arrangement permitting the air to pass round the
edge of the leather washer during the outward movement of the piston but pro-
viding an air-tight piston ring on its return or inward movement. The piston rod
emerges from the free end of the cylinder and is jointed to the extremity of a short
projecting arm secured to the door. From this arm a cord passes over suitably
placed pulleys to a weight hanging preferably on one side out of the way. It will
be obvious that the pull or power exerted by the weight upon the door will be
uniform throughout its entire opening and closing traverse.
By arranging the air cylinder as above described the door when wide open, that
is to say at about right angles to its position when closed, exerts its greatest
thrust or power upon the piston, such power gradually decreasing as the door
travels radially to its closing point. Thus the closing of the door by the action of
the weight will cause the air within the cylinder to be compressed and the
cushioning or arresting effect to be produced at a point determined by the adjust-
ment of the regulating valve; the remaining portion of the closing operation being
performed when the thrust upon the piston and its resisting power are nearly
exhausted.
In the accompanying Drawings Fig. 1 is a side view and Fig. 2 a plan view
shewing the arrangement of door closing or check apparatus as above described.
A is the door; B the frame or jamb; C the air cylinder; D the piston rod; E the
short projecting arm; g a cord from the armi E passing over pulleys h, h to a
weight i. is a hinge plate carrying the jointed end of the air cylinder C.
In Fig. 4 the details of the air cylinder and piston rod are shewn enlarged. The
screw (which has preferably a thin washer of leather or other suitable material

page_text: interposed between the screw head and the end of the cylinder), by being screwed
further in or out, allows the air to escape more or less freely as required through
the air duct m. n is a leather washer secured to the concave end of the piston
block o by a fastening screw p, this arrangement permitting the air to pass round
the edge of the washer during the outward movement of the piston rod but pro-
viding an air-tight piston on its return or inward movement, the peculiar
construction of the piston dispensing with the necessity of a back pressure valve
as usually required.
Fig. 5 is a view of my improved apparatus having a springs as the door closing
medium in lieu of a weight as shewn in Figs. 1 and 2.
Fig. 3 is a diagram view shewing the relative power exerted by the door A upon
the air cylinder C in the several positions indicated between the wide open and closed
points o aud c. It will be observed by reference to the vertical dotted lines that
as the door approaches the closing point c the ratio of resistance of the cylinder
gradually decreases, thus permitting the door after the cushioning or check effect
has been produced in the ordinary manner to gradually increase its speed as it
approaches the closing point by reason of its gradually overcoming the resistance
of the cylinder, thus differing from those arrangements of door check apparatus in
which the air cylinder affords an uniform resisting power between the check and
the closing point. The door inay, therefore, if desired be readily arranged to
reach the closing point with sufficient impetus to latch itself. The above described
result is similar to that which would obtain if the regulating valve 1, as the door
approached the closing point, were to be gradually opened wider and wider to
allow of a gradually increasing escape of the compressed air from within the
cylinder.
"
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
1. The arrangement of a hinged or pivotted air cylinder in combination with a
weight or equivalent closing medium whereby the resisting power of the air
cylinder relatively to the traverse of the door gradually decreases as the door
approaches its closing point substantially as described and shewn in the Drawings
for the purpose specified.
2. The combination of parts constituting the air cylinder and attendant
mechanism shewn and described with reference to Fig. 4 of the Drawings for
the purpose specified.
Dated this 21st day of September 1885
CHARLES HIGGIN MAXSTED,
Westholme, Lancaster.