Improvements in or relating to Door Operating Mechanism, chiefly Designed for use in connection with Lifts.
Year: 1899

page_text: Improvements in or relating to Door Operating Mechanism, chiefly
Designed for use in connection with Lifts.
I, HAROLD ROWNTREE, of 76, West Jackson Street, Chicago, State of Illinois,
United States of America, Manufacturer, 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 relates to a door operating mechanism.
The object of the invention is to provide efficient means for operating doors,
and particularly the doors at the landings of elevator shafts.
A further object of the invention is to provide means for efficiently cushioning
the door as it approaches the limits of its movements.
The invention consists substantially in the construction, combination, location
and relative arrangement of parts, all as will be more fully hereinafter set forth,
as shown in the accompanying drawings, and finally specifically pointed out in
the appended claims.
Referring to the accompanying drawings and to the various views and reference
signs appearing thereon,
Fig. 1, is a view in elevation illustrating the general arrangement of apparatus
embodying the principles of the invention as applied to the operation of the doors.
at a landing of an elevator shaft.
Fig. 2, is a view in vertical section of a car showing the arrangement of trip
mechanism for throwing the door-operating mechanism into action.
Fig. 3, is a detail view, parts in side elevation and parts in longitudinal sec-
tion, showing the mechanism for operating the door, and also the means for
cushioning the door at the limits of its movements.
Fig. 4, is a detached broken detail view in top plan of a portion of the con-
struction shown in Fig. 3.
Fig. 5, is a detached detail sectional view illustrating the arrangement of valves
through which the door-operating mechanism is controlled.
The same part is designated by the same reference sign wherever it occurs.
In the arrangement of apparatus for automatically operating doors or gates
at railway stations or in elevator service, and particularly in the latter case, it is
important to provide means for operating the doors or gates which are control-
lable from the car and which may be thrown into action from the car
only when
it is desired to operate the door; for instance, in the case of elevator service it is
desirable to provide means, under the control of the elevator conductor, whereby
the door at any particular landing of the elevator shaft or well may be opened
only when the car arrives at that particular landing. It is also of importance to
provide means for efficiently cushioning the door in its movements to open or
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page_text: closed position in order to avoid slamming, whereby the door may be opened or
closed easily, noiselessly and without shock.
It is the special purpose of the present invention to provide means for accom-
plishing these results in a simple and efficient manner.
In the accompanying drawings illustrating an arrangement of apparatus em-
bodying the principles of the invention, reference sign A, designates an elevator
car; B, the door at a. landing of the elevator shaft; and C, a cylinder suitably
supported upon a bar or beam D, fixed in the framing of the elevator shaft. The
door B, may be mounted in the framing of the elevator shaft or well to operate
in any desired manner. In the particular form shown, the door B, is mounted
upon hangers E, suitably supported: upon a beam F, whereby said door may slide
back and forth. Arranged within cylinder C, is a piston G, having a rod H, from
which suitable connection is made to the door, whereby when said piston G, is
moved within cylinder C, the door is operated or moved correspondingly. Many
different forms of connections between the door and piston H, may be adapted
for use in connection with the invention. A simple and efficient arrangement is
shown, wherein a lever J, is pivotally connected at one end to a bracket, or in
any other suitable or convenient manner, as at K, and is loosely and slidingly
connected at the other end thereof to one edge of the door. A link L, pivotally
connects piston H, to lever J, at a point intermediate the ends of such lever.
From the foregoing description it will be seen that when piston G, is moved
back and forth within cylinder C, the door B, will be moved through the described
connections back and forth into open or closed position, according to the direc-
tion in which said piston is moved.
The piston G, may be actuated under any convenient form of pressure, whether
steam, water, or compressed air. Preferably, I employ compressed air for the
purpose stated, and in Fig. 1, I have shown a system wherein compressed air is
employed, and wherein reference sign O, designates a compressed air reservoir,
to which air is supplied through pipe connection N, from a suitable air pump M.
Communicating with reservoir O, is a supply pipe connection P, which is arranged
to extend throughout the entire length of the elevator shaft or well. A suitable
pressure regulator Q, may be employed to regulate the pressure supplied to supply
pipe P. An exhaust pipe R, is also arranged to extend throughout the length of
the elevator shaft or well.
In the application of the principles of my invention to the operation of doors
at the landings in an elevator shaft or well, it will be understood that an opera-
ting cylinder C, is located adjacent to each door or landing throughout the eleva-
tor shaft or well, the piston in such cylinder being suitably connected, as above
described, to the door at the same landing therewith. Therefore, both the supply
pipe P, and the exhaust pipe R, are in suitable connection with the cylinder at
each door to be operated. This connection is shown generally in Fig. 1, and more
in detail in Figs. 3, & 4, wherein reference sign 6, designates an enclosed valve
casing, into which the supply pipe connection 7, delivers. Arranged within valve
casing 6, are three port openings-8, 9, & 10. Port opening 10, opens communi-
cation between the chamber of valve casing 6, and one end of cylinder C; for
instance, the left hand end of said cylinder, as viewed in Fig. 3, and at a point
on the left hand side of piston G. Port opening 8, communicates through a pipe
connection 11, with the opposite end of the cylinder C, while port opening 9,
establishes communication between the interior or chamber of casing C, and the
exhaust pipe R, through pipe connection 12. A valve 13, is arranged to control
the port openings 8, 9, & 10. This valve may be of any suitable form or con-
struction, but preferably, and as shown, provided with a recess 14, on the face
thereof arranged to bring exhaust port opening 9, into communication with either
of the port openings 8, or 10, when said valve is suitably moved. In the particular
arrangement shown, valve 13, occupies a position such as to establish communi-
cation between port openings 9, & 10, thus leaving port 8, uncovered. Under
this arrangement cylinder C, is exhausted from its left hand end, and air pres-

page_text: sure is supplied thereto at the right hand end through connection 11, from the
chamber of casing 6; therefore, piston G, will be at one of its extreme limits of
movement. When, however, valve 13, is shifted so as to establish communication
between ports 8, & 9, the reverse of this condition will be established; that is to
say, the right hand end of cylinder C, will be opened to exhaust and the left
hand end of such cylinder will be opened to supply pressure, and hence piston G;
will be moved to the opposite limit of its travel from that shown in Fig. 3.
Many specifically different arrangements of apparatus may be employed for
operating valve 13. In the particular form shown, to which, however, the inven-
tion is not limited, I suitably journal a rock shaft 15, in valve casing 6, and the
valve is connected in any suitable or convenient manner to an arm 16, of said
rock shaft. Rock shaft 15, is arranged to project through valve casing 6, and
mounted thereon is a trip arm 17, through which said rock shaft, and hence said
valve, is actuated. This trip arm may be operated or rocked by any suitable
arrangement of means controllable from the car. In the particular form shown,
to which, however, the invention is not limited, I mount on each car a trip bar 18,
having the inclined or bent ends 19, and suitably supported, as shown in Fig. 2,
upon the ends of bell crank levers 20. These bell crank levers are suitably
connected at their other ends as through a bar 21, to which is connected a chain,
rope, or other connection 22, leading to a lever 23, arranged to be operated in
any suitable or convenient manner by the elevator conductor, as through the
foot treadle 24. Spring 25, normally holds trip bar 18, retracted into such posi-
tion as to permit the car to pass a landing without engaging trip arm 17, at that
landing. If, however, it be desired to operate the door-operating mechanism at
any particular floor or landing, the elevator conductor will press treadle 24, when
the car approaches that particular landing, thereby rocking lever 23, and hence
through connections 22 & 21, rocking bell crank levers 20, in a direction to pro-
ject trip bar 18, against the action of spring 25, and into position to engage trip
lever 17, at the particular landing or floor the door of which is to be operated.
The bent ends 19, of trip bar 18, facilitate the easy engagement of trip bar 18,
with trip arm 17.
From the foregoing description it will be seen that through means controllable
from the car, trip arm 17, may be rocked to throw into action the door-operating
mechanism at any particular or desired floor or landing of the elevator shaft or
well, and whether the car is ascending or descending. The rocking movement of
trip arm 17, is normally opposed by a spring 26, the action of which is to hold
said trip arm, and hence rock shaft 15, and valve 13, in position to normally open
one end of cylinder C, to exhaust and the other end thereof to the air pressure,
whereby piston G, is held normally in one limit of its movement. This limit of
movement corresponds to the closed position of the door. Therefore, in their
normal condition the parts are arranged to normally close the doors, and when
the apparatus is thrown into action through the rocking of trip 17, the door will
be opened.
In order that the piston rod H, may be suitably steadied and guided in its
movements, I connect said piston rod to a cross head 27, mounted to slide back
and forth upon supporting bar or beam D. An arm 28, is connected to move
with cross head 27, and trip arm 17, is provided with lugs, indicated at 29,
arranged to embrace or engage said arm 28, in order to hold said arm and prevent
the same from being accidentally thrown out of position. Bar 28, is provided
with a notch or seat, indicated at 30, into which a projection 31, of trip arm 17,
engages when the parts are in their normal position, that is, when the door is
closed, thereby locking the door in its closed position. Thus it will be seen that
all the doors throughout the elevator shaft or well are normally in their closed
position and are locked against movement until trip arm 17, is rocked, and the
means for rocking said trip arm, as will be seen from the foregoing description,
are controllable from the car.

page_text: I will now describe the arrangement for cushioning the door as it approaches
either of the limits of its movements.
Upon a bracket 32, suitably mounted on a fixed part of the framing, as for
instance, upon bar or beam D, is pivotally mounted at one end, as at 33, a cylin-
der 34, in which operates a piston 35, suitably formed on or connected to a piston
rod 36, arranged to project through the end of said cylinder and pivotally con-
nected, as at 37, to a crank pin mounted upon the face of a gear wheel 38, said
gear wheel being suitably journaled in bracket 32. Suitably connected to cross
head 27, is a rack bar 40, the teeth of which are arranged to engage the teeth of
gear 38, whereby when said cross head is moved said gear 38, is rotated.
Cylinder 34, is intended to contain non-compressible fluid, such, for instance, as
glycerine, water, or other suitable liquid, and piston 35, is provided with a series
of openings 41, therethrough. A flap or disk 42, is loosely mounted upon the
end of piston 35, for movement relative thereto.
From the foregoing description it will be seen that when piston 35, moves
toward the upper end of cylinder 34, the fluid will readily pass through the open-
ings 41, in said piston, thus offering but slight resistance to the upward movement
of said piston. Upon the downward movement of said piston, however, flap or
disk 42, will immediately close said openings 41, and hence prevent the passage
of fluid through openings 41, and forcing such fluid to pass between the peri-
pheral edge of piston 35, and the inner wall of cylinder or chamber 34, said piston
being of smaller external diameter than the internal diameter of said cylinder.
By forcing the liquid contained in cylinder or chamber 34, to pass around the
edges of cylinder 35, instead of freely through the openings 41, a cushioning
resistance is secured which enables the door to be brought easily to the limit of
its travel or movement, and in order that a cushioning effect may be secured
at each limit of movement of the door, the size and relative arrangement of
gear 38, and rack 40, are such that when the main door-operating piston G, travels
from one end of main cylinder C, to the other, the cushioning piston 41, will make
a complete excursion from one end of cylinder or chamber 34, to the other end
and back again.
Instead of the arrangement above described for securing a cushioning of the
door as it nears the limit of its travel, or in conjunction and in co-operation there-
with, the lower end of chamber or cylinder 34, may be slightly contracted in
internal diameter, as indicated at 43, whereby the fluid contained in said cylinder
or chamber is more closely confined at the extreme end of said cylinder, thereby
securing an increased cushioning effect.
Of course it will be understood that the space, or rather the relative size of
cushioning piston 41, is suitably proportioned to the amount of cushion desired.
From the foregoing description it will be seen that when main controlling
piston G, approaches the limit of its movements in one direction the cushioning
piston 41, is also approaching the limit of its stroke towards the cushioning end
of cylinder 34, and when the main controlling piston G, is approaching the other
limit of its stroke the cushioning piston will also be coincidently approaching
the same or cushioning end of cylinder 34, as before, but when the controlling
piston G, is at the middle of its stroke the cushioning piston will be at the opposite
limit or end of cylinder 34. Therefore, during the first half of the stroke of the
controlling piston G, in either direction, practically no resistance is offered to the
proper operation of the door, but from this point onward a resistance is offered
to the operation of the door. This resistance may be made to gradually and
steadily increase, and this increase in resistance may be effected in either of two
different ways. For instance, piston 41, can be made to travel at a speed coincident
with the speed of travel of the main controlling piston G, and the cushioned cylin-
der or chamber 34, may be made of decreasing internal diameter, as above stated,
and as indicated at 43. From this arrangement it will be seen that the opening
for the escape of the fluid around the edge of cushioning piston 41, gradually

page_text: decreases as said piston approaches the cushioning end of said cylinder or chamber,
thus increasing the resistance offered to the movement of the door. Instead of
this arrangement, however, or in conjunction and in co-operation therewith, the
speed of cushioning piston 41, may be acclerated with reference to the speed of
the controlling piston G. This acceleration of speed may be secured in any
suitable or convenient manner; for instance, by suitably regulating the relative
location and arrangement of the parts in such manner that when the main or
controlling piston G, is about midway its stroke the crank pin connection 37,
is at a dead point with respect to the axis of rotation of gear 38, and with the
cushioning piston at the top limit of its stroke. At this point it will be observed
that piston 41, travels at a comparatively slow speed with respect to the speed
of travel of piston G, but when piston G, approaches the end of its stroke, the
speed of the stroke of piston 41, is increased, because crank pin connection 37,
has passed beyond its dead line, and therefore much greater resistance is offered
as the speed of piston 41, increases.
Thus in both cases a gradually increasing resistance is secured, thus securing
a perfect cushioning of the door as it approaches the limits of its movement in
either direction. Many changes, variations and alterations in the details of con-
struction and arrangement would readily suggest themselves to persons skilled
in the art and still fall within the spirit and scope of my invention. While,
therefore, I have shown and described a specific arrangement and embodiment
of the principles of my invention, I do not desire to be limited or restricted thereto.
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. In an elevator, the combination of a door, a cylinder and piston actuated by
fluid pressure, said piston operatively connected to the door, whereby when said
piston is actuated said door is moved, a second cylinder and piston operatively
connected to the door, said second cylinder adapted to contain a non-compressible
fluid, whereby the door is cushioned as it nears the end of its travel, and means
for increasing the cushioning effect as the door approaches the limits of its move-
ment, as and for the purpose set forth.
2. In an elevator, the combination of a door, a cylinder and piston actuated
by fluid pressure and operatively connected to the door, a cushioning cylinder
and piston operatively connected to the door, and means for accelerating the
speed of travel of said cushioning piston as it approaches the limit of its stroke,
whereby the fluid contained in said cushioning cylinder will offer increased resis-
tance to the motion of the door as it nears the end of its travel, as and for the
purpose set forth.
3. The combination with a door, of means for operating the door, a cushioning
cylinder, connections between the piston of said cylinder and said door, and
means for acelerating the speed of travel of said cushioning piston as the door
approaches the limits of its movements, as and for the purpose set forth.
4. The combination with a door, of a cylinder and piston, connections between
said piston and door, whereby when said piston is moved in said cylinder said
door is moved to open or closed position, a cushioning cylinder having a piston,
and connections between said cushioning piston and said operating piston, and
adapted to increase the speed of the cushioning piston as it approaches the limits
of its stroke, whereby as the door approaches the limits of its travel it is
cushioned, as and for the purpose set forth.
5. The combination with a door, of an operating cylinder and piston, and con-
nections between said piston and door whereby when said piston is operated said
door is opened or closed, a cushioning cylinder and piston, and connections
between said cushioning piston and said operating piston whereby when said
operating piston moves from one limit to the other said cushioning piston makes

page_text: a complete excursion from one end of the cushioning cylinder to the other and
back again, as and for the purpose set forth.
6. The combination with a door, of an operating cylinder and piston, connec-
tions between said operating piston and the door, a cushioning cylinder and
piston, said cushioning cylinder adapted to contain a non-compressible fluid, said
cushioning piston being perforated, connections between said cushioning piston
and said operating piston whereby when the latter moves from one limit of travel
to the other said cushioning piston makes a complete excursion from one end of
said cushioning cylinder to the other and back again, and means for closing
the openings in said cushioning piston when said piston moves in one direction
and arranged to uncover said openings when said cushioning piston moves in
the opposite direction, as and for the purpose set forth.
7. The combination with a door, of an operating cylinder and piston, connec-
tions between said piston and the door, a cushioning cylinder and piston, a gear-
ing actuated coincidently with the movements of the operating piston for actuating
said cushioning piston, as and for the purpose set forth.
8. The combination with a door, of an operating cylinder and piston, connec-
tions between said piston and the door, a cushioning cylinder and piston, and
gearing intermediate said cushioning piston and operating piston, whereby as the
latter approaches the limits of its travel in either direction the movements of said
cushioning piston are accelerated, as and for the purpose set forth.
9. The combination with a door, of an operating cylinder and piston, connec-
tions between the door and said piston, a gear wheel, upon the face of which
the rod of said cushioning piston is pivotally connected, and a rack actuated coin-
cidently with the movements of said operating piston for rotating said gear, as
and for the purpose set forth.
10. The combination with a door, of an operating cylinder and piston, connec-
tions between the door and said piston, a cushioning cylinder and piston, means
actuated by the movements of said operating piston for reciprocating said cushion-
ing piston, said means arranged to move said cushioning piston from one end
of said cushioning cylinder to the other and back again during the travel of said
operating piston from one limit to the other, said cushioning cylinder contracting
in internal diameter at one end thereof, as and for the purpose set forth.
11. The combination with a door, of a cushioning cylinder and piston, said
piston fitting loosely in said cylinder and provided with openings therethrough,
a flap or valve arranged to cover and uncover said openings, said flap valve being
loosely connected with respect to said piston, means for operating said door, and
connections between said operating means and said piston whereby the move-
ments of the door are resisted as the door approaches the limits of its movement,
as and for the purpose set forth.
12. The combination with a door, of an operating cylinder and piston, connec-
tions between said piston and door, a valve for controlling said cylinder, a trip
arm for said valve means carried by the car for operating said trip arm, said trip
arm when in normal position arranged to lock the door in closed position, and
means for cushioning the door as it approaches the limits of its movement, as and
for the purpose set forth.
13. The combination with a door, of an operating cylinder and piston, connec-
tions between said piston and the door, a valve for controlling said cylinder, a
_trip arm for actuating said valve, said trip arm when in normal position arranged
to lock the door in closed position, means carried by the car for operating said
trip arm, and means actuated by the movements of said operating piston for
cushioning the door as it approaches the limits of its travel, as and for the purpose
set forth.
14. The combination with a door of an operating cylinder and piston, a cross
head actuated by said piston, connections between said cross head and door, a bar
carried by said cross head and provided with a notch, a valve for controlling said

page_text: cylinder, a trip arm for operating said valve, said trip arm provided with a pro-
jection arranged to enter the notch in said bar, whereby the door is normally
locked in closed position, as and for the purpose set forth.
Dated this 4th day of February 1899
HAROLD ROWNTREE.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.