Year: 1898

page_text: Date of Application, 19th Apr., 1898-Accepted; 9th July, 1898
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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 has reference to door checks, such as are employed for prevent-
ing too violent closing of swinging doors and the like, and relates more particu-
larly to that class of door checks in which the resisting medium is a liquid. The
invention is more particularly although not exclusively adapted to be employed
with door checks in which a spring for closing the door automatically is com-
bined with the check in a single structure. My invention has special reference
to the piston-operating mechanism and to the means provided for operating a
regulating valve located in the piston, the chief object of the invention being to
provide a door check that shall be simple, compact, durable and capable of being
constructed inexpensively and its parts assembled or taken apart with ease.
In order that the said invention may be clearly understood I will describe the
same fully with reference to the accompanying drawings, in which
Figure 1 is an elevation of a door check and a portion of a door and door frame
showing the external appearance of the check and the devices employed for
connecting it to the door frame;
Figure 2 is a plan view of the check so attached, showing, in dotted lines the
position of the operating levers when the door is partly open;
Figure 3 is a central vertical section of the check, showing its mechanism;
Figure 4 is a detail view illustrating the action of the cam mechanism;
Figure 5 is a detail sectional view showing the regulating valve on a larger
scale;
Figure 6 is a similar view, showing a slightly different mechanism for opera-
ting the regulating valve;
Figure 7 is a transverse section of the check on the line 7-7 of Figure 3;
Figure 8 is a detail view of the plate which closes the working cylinder, with
the cam shaft, operating shaft, and gearing attached, ready for insertion into
the casing of the check; and
Figure 9 is a central vertical section of a door check which does not contain
a spring, but is designed to be used without a spring, or in connection with an
independent spring.
In the drawings, 10 indicates the main casing of the check, provided with
flanges 11 by which it may be attached to the door 12. 13 and 14 indicate the
ordinary hinged operating levers by which the operating shaft of the check is

page_text: rotated during the opening and closing of the door, one of the levers being con-
nected to this operating shaft, 15, and the other to the door frame. The cas-
ing 10 of the check shown in Figures 1, 2, and 3, is divided into an upper or
spring chamber 16, Figure 3, within which is the spring 17 which tends always
to close the door or to hold it closed; and a lower chamber or working
cylinder 18, in the upper portion of which are the gearing and cam for operating
the piston. The lower portion of this chamber, the working cylinder proper,
has within it a closely-fitting piston, 20, provided with an eccentrically-placed
piston rod 21, which at the top is provided with a projecting stud or cam piece 22
engaging a cam 23 on a cam shaft 24 which is mounted in bearings in lugs pro-
jecting downward from a plate 30 separating the spring and working chambers,
and which cam shaft is driven by bevel gear wheels 25 and 26 from the shaft 15.
The support of the cam shaft in bearings formed on or secured to the plate 30
constitutes an important feature of my invention. By this means I avoid boring
through the casing in order to fit bearings for the said shaft; and I am also
enabled to readily remove the mechanism when desired.
The cam mechanism by which the piston is reciprocated operates in the follow-
ing manner: In the edge of the cam 23 is a recess 27, into which projects the
stud or cam piece 22 of the piston rod when the piston is in the position shown
in Figure 3. One shoulder 28 of the cam is arranged to work against the under
side of the stud 22, and the other shoulder 29 is arranged to bear downwardly
upon the stud 22 and top of the piston rod 21, when forcing the piston down-
ward. The shape of the cam and of the stud 22 is such that when the piston
has been raised to the upper limit of its travel, the cam has moved to such a posi-
tion that the stud 22 is no longer within the recess 27, and the cam slides idly
past the stud without causing further movement of the piston, and without
permitting the piston to descend. The cam is. so designed that the disengage-
ment of the stud 22 occurs before the door has been opened widely. In the
closing of the door, when the cam 23 has reached a position corresponding to
that position when the stud 22 became disengaged during the opening of the
door, the stud 22 again enters the recess 27 and the shoulder 29 of the cam presses
the piston downward. As hereinafter explained, in moving downward the piston
forces the liquid below it to pass through a restricted passage, thus checking
the closing of the door, and preventing too rapid closing thereof. But since the
cam does not engage the stud 22 until the door has been partly closed, the check
does not resist the action of the spring when the door first begins to close, but
acts only in time to prevent too rapid closing.
In order that the stud 22 may not be broken off, the shoulder 29 of the cam
may be extended or broadened, as shown in Figure 7, so that it bears directly
upon the top of the piston rod 21.
In order to prevent the piston from rotating and so carrying the piston rod
stud out of engagement with the cam, I provide that the piston rod works along
and is guided by a rib projecting from the side of the cylinder (see Figure 7).
There is a plane guide face on the said rib, and a corresponding face on the piston
rod, or on the stud forming the head thereof, where it comes in contact with the
said guide rib.
The joint between the plate 30 and the casing of the check is tight enough to
prevent the leakage of liquid in case the check should be upset at any time, the
plate being held in place by screws not shown in the drawings. The operating
shaft 15 passes through a closely fitting bearing in the plate 30, which bearing
is so tight that no fluid can escape through it.
The spring chamber 16 has a cover 31. A bushing 32 surrounds the shaft 15,
and has a bearing in the cover 31. The spring 17 is an ordinary helical spring,
one end of which engages a slot 33 in the bushing 32, and the other end engages
a slot 34 in the side of the chamber 16. The bushing 33 is provided with rat-
chet teeth at the top, as shown in Figure 2, and a pawl 44 engages these ratchet
teeth, so as to hold the spring under tension.

page_text: In the piston 20 is a non-return valve 35, which permits free passage of liquid
from the upper side of the piston to the lower side thereof, when the piston
rises, but which prevents the passage of liquid through it when the piston des-
cends. In the piston there is also a passage 36, arranged to be closed to such an
extent as may be desired by a screw valve plug 37 forming the return valve for
the liquid. Upon the end of the said valve plug is a spur wheel 38 adapted to
engage with a spur pinion-rod 39 which passes through the bottom of the casing
of the check and has upon its end a milled head 40. This pinion-rod 39 has
also a collar 41, and a bushing 42 is screwed into the opening in the casing
through which said rod passes, and holds it in place. A suitable packing
material may be placed between the collar 41 and the bushing 42 to prevent the
escape of liquid.
The upper end of the pinion-rod enters a socket 43 in the piston 20 when
the piston is at the lower limit of its travel. It is in this position that the
pinion rod is in engagement with the spur wheel 38 on the regulating screw 37.
By turning the milled head 40, when the parts are in this position, (the position
being that which corresponds to the closed position of the door) the flow of fluid
through the passage 36, and therefore the resistance offered by the check to the
closing of the door may be regulated.
When the piston rises, the spur wheel 38 moves out of engagement with the
pinion 39, but when the piston descends, the spur wheel will engage again with
the pinion. To facilitate the engaging of the teeth of the gear wheel 38 and
pinion as the piston descends, the rods of the teeth of the pinion are bevelled. If
it be thought, however, that it is preferable not to permit the wheel 38 and
pinion 39 to disengage, the pinion may be prolonged as shown in Figure 6, so
that in the normal operation of the door check the piston will never rise so far
as to move the spur wheel 38 out of engagement with the pinion.
The passage 36 in the piston is a right-angled passage, so that the pressure
as the piston descends is squarely against the side of the screw 37 and there is
no tendency, therefore, due to this pressure, for the screw to revolve and to change
the adjustment of the valve.
The operation of the check is as follows:
When the door is opened the shafts 15 and 24 are rotated in such a direction
that the cam 23 raises the piston 20, thus causing liquid to pass from the space
above the piston through the non-return valve 35 into the space below the piston.
When the door is only partly open the shoulder 28 of the cam slips away from
the stud 22 (as shown in Figure 4) and the piston remains stationary, though
the door may continue to open and the cam shaft to revolve. The rotation of
the shaft 15 while the door opens increases the tension of the spring 17. The
door is closed automatically by the spring 17 as soon as said door is released.
As it closes, the cam 23 again engages the piston rod, and forces the piston down,
the liquid in the working cylinder passing through the passage 36, since the
non-return valve 35 does not permit upward flow of liquid through it. Since
the passage 36 is restricted by the screw 37, the liquid can only pass through it
slowly, so that the door cannot close rapidly, but its rapid movement, produced
by the spring, is checked. By turning the milled head 40, the rate of closing
of the door may be regulated as desired.
It is obvious that the piston-reciprocating mechanism and the valve-regulating
mechanism herein described are applicable to pneumatic door checks as well as
to liquid door checks. Moreover the check need not have a spring combined with
it in the same structure, and in Figure 9 a check is shown which does not have
a spring combined with it, but may be used with an independent spring or may
be used where no spring is required
In the drawings, the check is shewn as arranged for use on a door opening to
the right. To adapt it to a door opening to the left, the gear wheel 26 should
be placed on the opposite side of the cam 23, the spring 17 should be reversed,

page_text: and the pawl 44 brought into engagement with the teeth on the right-hand side
of the bushing 32, in Figures 1 and 2.
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. A door check provided with a detachable plate for closing the working
chamber, a transverse shaft suspended from said plate, mechanism operated by
the revolution of said shaft for actuating the piston, and a longitudinal shaft
connected by gearing to the transverse shaft, all substantially as described and
for the purpose specified.
2. The combination, with the working chamber, and the piston therein, of a
rotary cam having shoulders, one of which is adapted to engage with a cam
piece or stud on the piston rod and move the piston outward, and the other of
which is arranged to bear against the end of the piston rod for pressing the
piston inward, said cam and cam piece being so shaped that they disengage when
the cam is in a position corresponding to a partly open position of the door, sub-
stantially as described and for the purpose specified.
3. The combination, with the working chamber, of a piston within said cham-
ber having a piston rod working along and guided by a guide rib projecting
from the side of said working chamber and having a plane guide face, the cor-
responding face of the piston rod where it comes in contact with said guide rib
being also plane, whereby rotation of the piston in the working chamber is pre-
vented, substantially as described.
4. The combination, with the piston, of a non-return valve adapted to permit
free passage of fluid from one side of the piston to the other, a valve-plug in
said piston adapted to restrict a passage therein through which reverse flow of
the fluid may take place, an operating rod projecting through the wall of the
chamber in which the piston works, and gearing substantially as described for
connecting together the valve-plug and the operating rod, so that the said valve-
plug may be adjusted for the purpose specified.
5. A door check having its parts constructed, arranged and combined to oper
ate substantially as hereinbefore described with reference to the accompanying
drawings.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.