IMPROVEMENTS IN AND RELATING TO DOOR-CHECKS OR DEVICES FOR PREVENTING THE SLAMMING OF DOORS
Year: 1881

page_text: LETTERS PATENT to Henry Harris Lake, of the Firm of Haseltine, Lake,
and Co., Patent Agents, Southampton Buildings, London, for an Invention
of "IMPROVEMENTS IN AND RELATING TO DOOR-CHECKS OR DEVICES FOR
PREVENTING THE SLAMMING OF DOORS." A communication from abroad by
Lewis Carey Norton, of Boston, Massachusetts, United States of America,
Builder.
COMPLETE SPECIFICATION filed by the said Henry Harris Lake at the
Office of the Commissioners of Patents on the 21st December 1881.
HENRY HARRIS LAKE, of the Firm of Haseltine, Lake, and Co., Patent Agents
Southampton Buildings, London. "IMPROVEMENTS IN AND RELATING TO DOOR-
CHECKS OR DEVICES FOR PREVENTING THE SLAMMING OF DOORS." A commu-
nication from abroad by Lewis Carey Norton, of Boston, Massachusetts, United
States of America, Builder.
The object of this Invention is to prevent the slamming of doors in the closing
of the same.
The said Invention relates to that class of door-checks in which compressed air
is used to cushion a piston which moves with the door as the latter closes, and by
which the notion of the same is controlled.
The said Invention comprises a peculiar form of door-check and spring herein-
after described; it also comprises the combination with a door and its jamb of a
door-check of the class first herein referred to by means of certain connecting and
operating mechanism, all so arranged together that when the door is closed at a
constant rate of speed there will be a material increase in the rapidity with which
the piston is driven home as the door nears the jamb, and consequently the
resisting or cushioning power of the air in the cylinder in front of the said
piston will not materially affect the motion of the piston until the same has been
driven nearly home and the door is about to strike the jamb.
The said Invention further comprises certain other combinations of parts herein-
after described, all assisting in various ways to effectually prevent the slamming of
doors.

page_text: accompanying Drawing, in which
Figure 1 is a perspective view of the door-check with the brackets and adjacent
parts attached, so that it may be used upon the hinge side of the door.
Figure 5 is a perspective view of the same device attached to a door and its
frame.
Figure 9 shews the door-check with a modified form of bracket and arm adapted
for use upon the side of the door opposite to the hinge side, and
Figure 10 shews this device as it appears when in use.
The remaining Figures are hereinafter referred to, and some of the same are
drawn to a larger scale than others.
A represents a door-frame, and B the door; C represents a cylinder, having at
its ends the cap c, c¹; the cap c is provided with a hole in its centre through
which passes a piston-rod D, to one end of which is attached a piston d provided
with suitable packing, as shewn in Figure 2, and adapted to move backward and
forward in the cylinder C.
Around the rod D within the cylinder is a spiral spring E adapted to be
compressed between the cap c and piston d when the piston is drawn back.
The
said cap c is provided with one or more holes by means of which the air in the
cylinder behind the piston can escape while the piston is being drawn back.
The cap c is provided with a valve which is adapted to open when the piston d
is drawn back, but which will close more or less tightly in proportion as the power
exerted in forcing the piston forward is greater or less. For this purpose the
cape is provided with a small hole ƒ passing through its centre; around this hole,
and but a short distance from it, is a small groove f₁; f represents a disc made of
soft leather, india-rubber, or other like substance of a diameter about equal to
that of the interior diameter of the cap c¹. That portion of the said disc which
rests on the flat part of the cap c¹³ is provided with two or more slits cut in it, all
as shewn in Figures 2 and 3.
The operation of the valve is as follows, that is to say-While the piston is
being drawn back all pressure is removed from the disc f, and the outside air
passes through the hole f, and between the inner surface of the cap c² and the
disc f, and then through the slits f into the cylinder. While the piston is being
forced forward it compresses the air in the cylinder more or less, and the disc is
thereby forced against the inner surface of the cap c', as shewn in Figure 2; the
disc forming with the inner surface of the said cap c¹ a joint more or less
air-tight according to the pressure exerted by the piston. If great pressure be
employed to force the piston forward the disc will be forced tightly into the
hole and groove f¹, and the amount of air which can escape through the slits f³
between the disc and the inner surface of the cap c² and through the hole in the
open air will be very small, consequently the air is compressed by the piston, and
at the same time retards its motion. If however only a little pressure be employed
to force the piston forward a much larger amount of air can escape, and there
is consequently a much less quantity of compressed air to retard the motion of the
piston.
By means of the groove f1 a ridge f4 is formed on the inner surface of the
cap c' next to the hole f. When the air in the cylinder is compressed it forces
the disc into both the hole f and the groove f' as before stated, and consequently
draws that part of the disc which rests upon the said ridge f* very tightly over
the same, and causes the formation of a joint which will be more nearly air-tight
than if no such ridge were there.
In case the air does not escape fast enough from the chamber in front of the
piston through the valve, and consequently the door closes too slowly, an outlet
may be provided through which a very small quantity of air may pass. It is best
to make this outlet adjustable in size, and a device for effecting this object is shewn
in Figures 2 and 3. It consists of a hollow rod or screw F of substantially the
length shewn, fastened with an air-tight joint into a hole in the cap c¹ and passing

page_text: through the disc f2 so that there will be a free passage from the interior of the
cylinder to the open-air. This hollow rod or screw is provided with screw-threads
upon its interior. A screw F¹ is employed to regulate the size of this passage, one
side of the said screw being filed flat. If the screw F' be screwed tightly into the
female screw F no air can pass through the said passage; but if this screw F' be
unscrewed one or more turns as its flat side is at a small angle with the axis of the
screw, as shown, the passage through the said screw F will be opened more or less
wide, depending upon the number of turns given to the screw F¹. By means of
this device a very accurate adjustment may be attained.
To the outer end of the piston rod is pivoted at k an arm G, wbich, in the device
shewn in Figures 1, 5, 6, 7, and 8, is provided with a bracket g adapted to be
screwed to a door, as shewn in Figure 5, and to allow the said arm to stand at any
required angle with the same. For reasons hereinafter stated the end of the armg,
which is attached to the piston-rod, is best made (in this form of device) in the
shape of a disc cast in one piece with the remainder of the arm, and arranged with
respect to the same, as shewn at K.
Pivotted to the disc K. at (see Figure 4) is a rod II, which is curved at one end
as shewn, and is hinged at the other end to the hinge-plate J, which is also hinged
to the cap c of the cylinder C. The purpose of this guide-rod H is to control the
length and direction of the piston's stroke, and its pivot k¹ acts as a fulcrum upon
which the arm G turns, and which is necessary for the proper working of the
device, as will be understood from the ensuing description. The hinge-plate J
is for the purpose of securing the door-check in place upon the lintel as hereinafter
described.
The device shewn in Figures 1 and 5 is designed to be used upon the hinge-side
of a left-hand door so termed. To attach it properly a point is found upon the
edge of the door-lintel, and distant from the hinge-edge of the door a little less
(say about an inch) than the length of the cylinder added to the length of the
piston's stroke. When the cylinder is of the usual length (about seven inches) this
distance will be about nine inches. The cylinder is then placed upon the lintel, so
that the hinge j rests upon the point so found with the guide-rod H toward the
hinge-edge of the door, and the said device is then screwed in place by means of
the hinge-plate J, so that the door in swinging will just clear the said cylinder aud
hinge-plate. The bracket g is then screwed to the door, so that the arm G will be
immediately under the cylinder and parallel with it.
The operation of this Invention will be understood by reference to Figures 6, 7,
and 8, which shew the position of the device when the door B is closed, when it
stands at an angle of 90 degrees with the lintel A, and when it is thrown wide
орец. In Figure 6 as the door is closed it is hidden by the lintel A, and cannot
therefore be indicated by any letter. The direction of the force, which is first
applied to the device by the opening of the door, is at substantially right angles to
the lintel; and if the door did not swing on hinges the distance which the piston
would be drawn out by this force would be equal to the distance traversed by the
door in this direction. But as the position of the bracket g (at which point the
force is applied to the arm by the door) alters during the swinging of the door, the
arm will be caused to turn on this bracket g and the pivots k, k, and to constantly
draw the end of the piston-rod away from the door-lintel. The cylinder will be
turned by the action of the arm upon the hinge j¹, and kept at nearly right angles
to the door until it stands at right angles to the lintel, when the cylinder will lie
nearly parallel with the same, and the arm nearly parallel with the door, as shewn
in Figure 7. It will be seen that as the position of the bracket g changes with
reference to the hinge-plate J during the opening of the door, the force which draws
out the piston and is exerted by the door through the arm G and bracket g upon
the piston-rod acts with less and less leverage upon the said piston-rod, and
consequently the piston will be drawn out and a less and less distance in proportion
to the distance traversed by the door as it opens, until, when the door stands at
right angles to the lintel, this force will be substantially expended. After the door

page_text: has passed this point and when the opening of the said door is continued, the angle
between the cylinder and the arm will become greater. The piston however will
be drawn out but little farther, that is to say, far enough only to allow a change
in the positions of the pivots k, l, as shewn in Figures 7 and 8, so that the force
of the spring within the door-check applied through the piston and piston-rod may
act upon the arm and cause it to turn on the pivot ¹ and close the door when it
is required to do so, the leverage acquired by the use of these two pivots being
sufficient to do away with any possibility of a dead point.
When the door closes the operations above described are reversed. The force
acting to close the door will only move the check slightly until the door is at right
angles to the lintel, but after that point is passed the nearer the door approaches
the jamb, the more directly will this force act upon the piston, and the motion of
the piston will be increased greatly in proportion to the rapidity of the motion of
the door as the door nears the jamb. Consequently the air in front of the piston
in the cylinder will be compressed more and more, and the valve closed tighter and
tigher until finally the piston is cushioned, and the door prevented from slamming.
The device shewn in Figure 1 is adapted to be used on the hinge-side of a door,
as before stated, and as thus arranged it can only be used upon a left hand door;
if it is to be used upon a right hand door, the same device is adapted for the
purpose, by simply unscrewing the screw which forms the pivot , and turning the
arın G through an are of 180 degrees upon the piston and piston-rod D, as a pivot,
so that the disc K will bear against the other side of the guide-rod H when the
guide-rod and the arm are screwed together again, this time by means of the screw
and the screw-hole ³. The device will then be screwed to the door and frame, as
before described.
In every case the guide rod should be upon the side of the device towards the
door-hinge, and when this form of device is used the cylinder should be screwed to
the door-frame over the door.
When it is desired to use the device upon the side of the door opposite to the
hinge side, the arm G is made of the form shewn in Figures 9 and 10, with the
post L pivotted to its outer end. When this form of device is used the cylinder is
screwed to the door, its position in reference to the door-hinge being determined, as
before. The device must always be so placed that the guide-rod will be upon the
side next the door-hinge. The post L which is pivotted to the arm G, as shewn, is
screwed to the door lintel above the door, as indicated in Figure 10; the cylinder
and arm being in this case side by side instead of one above the other, as is the
case when the other form of device is used.
The operation of this device with reference to the piston's stroke is in this case,
substantially the same as that before described, except that when this device is
used, the door cannot be swung through more than, say 120 degrees.
As shewn in Figures 9 and 10, the device is adapted to be used upon a left hand
door. If it be desired to use the same device upon a right hand door, the screw
holding the post L in place is removed, and the said post L attached by the same
pivot-hole and screw to the other side of the same end of the arm G.
The parts of this device, except the disc f' and piston packing are made
preferably of brass or iron, and they may be nickel-plated or ornamented in any
desired manner.
The hinge-plate J is ordinarily made about two inches long from
hinge to hinge, the guide-rod about eleven inches long, or long enough to reach
from its hinge j to the arm disc K, as shewn, and the arm G about seven inches
from its bracket g (or post L) to the point where it joins the piston-rod. These
dimensions are suitable for a door-check of ordinary length, that is to say, one
having a cylinder about seven inches long. The disc K is usually about an inch
and a quarter in diameter, and it is provided with four screw-holes, arranged as
shewn, one being at k for attachment to the piston-rod, two others at k¹ and les for
use in altering the device, so that it may be used on either a left or right handed
door, as before described, and one ² for use in cases where a longer stroke of the
piston is desired after the door has passed an angle of 90 degrees with the jamb

page_text: than is usually necessary. To lengthen the stroke the guide-rod is pivotted at
instead of either at kor k³, and the effect of this alteration will be readily
understood by supposing the pivot on which the arm turns in Figures 7 and 8 to
be at k instead of k¹.
As there is no necessity for altering the position of the pivots connecting the
arm, guide-rod, and piston-rod in the device shewn in Figures 9 and 10; the end M
of the arm G is usually made, as there shewn, instead of providing the arms with
a disc similar to the disc K.
Having thus fully described the said Invention, as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,
First. In a door-check, the combination of the cylinder and the piston therein
with the cap c' so as to form a chamber adapted for the compression of air, and
provided with two outlets, one adjustable by hand only, and the other automatically,
as above set forth and shewn in the accompanying Drawing.
Second. The combination of the cylinder, the cap c, the piston, the spring, the
cap c' with its valve, and the adjusting device F, FI, or its equivalent, all as above
set forth and shewn in the Drawing.
Third. The hollow rod or screw F and the adjusting screw F', arranged as
shewn and adapted for the purposes specified.
Fourth. The combination with a door and its frame of a door-check in which
the forward stroke of the piston is controlled by compressed air, and which is
provided with an arm whereby its piston-rod may be operated, a guide-rod
whereby the stroke of its piston may be controlled, and suitable devices for the
attachment of the said arm, guide-rod, and door-check to the door and its
frame, all connected and operating substantially as above set forth and for the
purposes specified.
Fifth. The combination of the door-check, the hinge-plate, the guide-rod, and
the arm G, provided with a suitable device for attaching it to the door or its
frame, all arranged and connected substantially as above set forth and for the
purposes specified.
Sixth. In a door-check, the combination of the piston-rod, the guide rod, and the
arm G with its adjusting disc K, all substantially as shewn and described.
Seventh. A door-check which embodies in its construction the above specified
novel features or any of them, and which operates as herein set forth and for the
purposes specified.
In witness whereof, I, the said Henry Harris Lake, have hereunto set my
hand and seal, this Twenty first day of December, in the year of our
Lord One thousand eight hundred and eighty one.
HENKY H. LAKE. (L.S.)