Improvements in Mechanism for Operating Doors and Gates of Freight Elevator Wells in Manufactories.
Year: 1891

page_text: Date: of Application, 28th Aug, 1891
Complete Specification Left, 28th May, 1892-Acospted, 23rd July, 1892
:
· PROVISIONAL SPECIFICATION.
Improvements in Mechanism for Operating Doors and Gates of
Freight Elevator Wells in Manufactories.
A communication from abroad by ORION LIVINGSTON DAVIS, of Rochester, in
the County of Monroe and State of New York, United States of America,
Manufacturer and Inventor.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E. of the Agency for
Foreign Patent Solicitors 6 Lord Street, Liverpool and 6, Bank Street,
Manchester both in the County of Lancaster and 323 High Holborn in the County
of Middlesex, Civil Engineer, do hereby declare the nature of this invention to be
as follows:
According to this invention, a light vertical continuous shaft is provided
extending from the lowest to the highest story of the building in which the
elevator doors are to be operated, so that all the doors of a vertical series, for
instance, opening into a well may be operated by it. This shaft is rotated con-
tinuously in one direction by some simple means, as a belt or cog wheels connecting
it with some convenient part of the power shafting in the building and
independently of the action or movements of the car, the shaft being outside of the
well and near the door ways therein.
At each story of the building a friction wheel about three inches in diameter is
secured rigidly to this shaft for operating the door of that story, the friction wheel
being located a short distance above the top of the door. The mechanism is the
same for each of the doors of the various stories.
The door to be operated is usually supported upon traverse rollers resting on a
track in a manner that is common and provided at its upper edge and near its
respective vertical edges with two arms which hold two parallel belts or straps.
These belts are horizontal as to their points of suspension but placed to stand
edgewise one on either side of the friction wheel and separated by a distance a
little greater than the diameter of said wheel,
Just outside of and in contact with each helt is a vertical roller held by a
horizontal sliding piece beneath the wheel, the axes of the two rollers the
friction wheel and the shaft being in the same vertical plane, transverse to the
plane of the door. The sliding piece is fitted to slide horizontally upon a bed-piece
rigid with a wall or part of the well, the motions of the sliding piece being in a line
of the plane just mentioned so that the rollers are in any case carried one directly
toward, and the other directly from, the friction wheel.
Now, if the sliding piece be moved in either direction, it will cause one or the
other of the idlers to growd its contiguous belt against the revolving wheel and, by
triotion, move the belt, and, consequently, the door. By shifting the sliding piece
in the opposite direction to bring the other belt against the wheel, the door will
be moved in the opposite direction, the shaft and the friction wheel revolving
continually in one direction.
A roller is attached to the car and a vertical cam lever is held in place near each
door to be operated by said roller as the car moves along the well, the cam lever
being connected with the sliding piece for the purpose of shifting the latter, as
above described.
The vertical operating shaft for the doors is made of such a length as to pass by
all the doors arranged in a vertical tier. This shaft is placed without the well and
near the doors to be operated, preferably enclosed in a hollow post and revolved
by an ordinary bolt leading onto a pulley from some convenient revolving shaft in

page_text: ร
by means of other gearing connecting it with the power snarting
of the building.
At a certain point is a friction wheel secured to the shaft by binding screws or
other simple means. A bed-piece is secured in a horizontal position beneath the
friction wheel to the front wall of the well or some part rigid therewith, in position
to have the shaft pass through an opening at its centre. This bed-piece may be
constructed with an upwardly projecting hub to form a bearing or support for the
shaft.
A sliding piece is fitted to move along bearings on the bed-piece formed with an
oval opening at its centre to pass over the hub. The form of bearings is
unimportant, provision being made simply to admit of a sliding motion of the
latter upon the former. The bed-piece may, if desired, be made in the form of a
letter H, and the sliding piece is formed with projecting parts to enter the end
openings therein. This sliding piece is provided with two vertical idling rollers
one on either side of, and level with, the friction wheel the axes of these rollers
and the wheel being parallel and in a vertical plane at right angles with the plane
of the door.
Drag belts preferably made of leather, canvas or similar material, are provided,
and are held one on either side of the friction wheel to be acted upon by it to
move the door. The belts are conveniently held by arms secured rigidly to the
door by iron straps; one arm being near each vertical edge of the door. As shown,
the arms hold prismatic blocks of wood, to the vertical edges of which the
respective belts are secured by simple fastenings. These arms overhang the vertical
edges of the door and the drag belts are stretched between them; and the arms
being formed with longitudinal slots, they may be moved in directions away from
each other to tighten the belts.
The door is supported by rolling hangers resting on a horizontal track-held on a
ledge over the door and rolls toward the right when closed and toward the left
when opened. When the door is closed, the left hand arm is near the shaft, and
when the door is open, the right hand arm is near the shaft, these arms alternately
approaching and receding from the shaft as the door is moved one way or the other.
By moving the sliding piece forward or backward, one or the other idling roller is
caused to press the drag belt near it firmly against the fiction wheel, thus causing
the door to be moved in one direction or the other as the case may be.
A vertical cam lever is held within the well upon a pivot in position to indirectly
actuate the sliding piece, a vertical spring bar being interposed between it & said
sliding piece. This spring bar is secured at its upper end to the sliding piece by a
simple bolt and held at its lower end by a pin. Normally, the cam-lever stands
inclined slightly in a direction away from the shaft, resting, for a stop, against a
wall of the hollow post. In this position, the swell of the lever will be in the way
of a roller projecting from the car as the latter moves up or down within the well.
Now, if the car be ascending, for instance, the roller will encounter the lower
inclined part of the swell of the lever and, as the ear continues upward, cause the
lever to crowd the spring bar and thus shift the sliding piece in a manner to cause the
inner roller to press the inner drag belt against the friction wheel. The result
of this is that said drag belt and the door are moved to the left to open the
passage way into the well.
The spring bar being flexible and elastic causes the belt to be held steadily
against the friction wheel notwithstanding the fact that the car, as it moves along
in the well, is liable to shake or joggle in a sidewise direction toward or from the
cam-lever and thereby exert an unsteady pressure against the latter.
F
When the car passes on, the sliding piece, spring-bar and cam-lever are
respectively thrown back to their normal positions by a laterally acting spring
pressing against the extended pin of the inner roller or some other convenient part
of the sliding piece. Also, when these parts are thus returned to their normal
positions, the position of the sliding piece is such that the outer roller presses the
outer belt against the friction wheel which causes the door to be closed. Thus it

page_text: will be seen that the normal positions of the various alternately acting parts
correspond with a closed position of the door.
The car has nothing to do with the closing of a door except to clear itself from
the cam lever by proceeding on its way, leaving the closing spring to act upon
the parts. The actions of the two springs cause the belts respectively to be held
against the friction wheel with a yielding pressure.
Recesses are formed in the inner faces of the respective belts, so that when, in
any instance, the door becomes fully closed or fully opened, contact between the
friction wheel and the belts will be broken; the wheel then becoming temporarily
inactive although continually revolving.
The sliding piece, coming in contact with the hub of the bed-piece when shifted
by the spring, limits its motion in that direction, so that the breaking of the
contact just mentioned between the belt and the friction wheel is rendered possible
and certain, and a similar contact between the sliding piece and bed-piece when the
former is moved in the opposite direction by the cam lever renders certain the
breaking of the contact described between the belt and the friction wheel,
The sliding piece is further provided with a rigid stud, and a spring catch or
hook is secured to the left hand arm in position to catch onto the stad when the
door is moved to the right and closed, thus serving to hold the door in that position
against any effort to open it by hand. When, however, the sliding piece is shifted
by the notion of the car, the stud becomes relieved from the spring catch and the
latter, with the arm, is permitted to move freely away to the left as the drag belt
is moved by the friction wheel to open the door.
The actuator is held by the car in any convenient manner so as to be thrown in
the way of the swell of the cam lever, or withdrawn.so as to pass the successive
cam levers without touching them.
The actuator is a wheel secured by means of holding jaws to a hand lever pivoted
to some convenient timber or part of the car so as to swing toward or from the
cam lever. A simple latch pivoted to the side of the hand lever to move in a
vertical plane and riding upon a stud rigid with the car, serves to hold the hand
lever in its forward position in which the wheel is caused to encounter the swell of
the cam lever as the car comes along. A tooth of the latch drops beside the stud
when the hand lever is pushed out, thus bolding the latter in position. When it is
wished to have the car pass any of the doors without opening them, the attendant
lifts the latch sufficiently to allow the tooth to clear the stud and immediately the
hand lever is thrown back by a spring pressing against it. This carries the wheel
out of the way of the various cam-levers so that all doors are passed without being
opened. The stud also acts as a stop for the backward movement of the hand
lever caused by the action of the spring.
When the belts are made of leather or eanvas, one or both of them are bent
against the friction wheel by the shifting of the sliding piece above described.
In case they are made rigid, as, of stiff iron, they are to be shifted bodily sidewise
against the friction wheel by means similar to those employed to shift the sliding
piece. In this case, the prismatic blocks, instead of being rigid with the respective
arms, are held to slide along the channels therein, the holding bolts at the same
time moving in the slots. When such rigid iron bars are employed, the friction
wheel is covered with leather or some, similar material to augment the friction
between it and the bars.
Or, again, when, for convenience of construction or adaptation, it becomes desirable,
a single rigid bar only, may be employed instead of two, such bar being placed
centrally between two friction wheels, turning in the same direction, that is to say,
turning so that the peripheries of the wheels shall pass the bar in opposite
directions, the wheels being placed a little further apart than the thickness of the
bar. As the bar is moved against one or the other of the wheels it, with the door,
will be carried in one direction, or the other as the case may be. In this
construction, as in the other, the bar may be shifted against the wheels or tho
wheels may be shifted against the bar, this being a mere matter of convenience in
.
030

page_text: construction and left to the mechanic, both being comprehended in the invention
herein shown and described.. Also said rigid bar or bars may be formed with
cogs along their vertical faces instead of with friction. surfaces, the periphery.of
the wheel or wheels being also formed with cogs to engage said cogs of the bars
the propriety of forming the contact parts smooth or with cogs being. also
determined by the mechanic or constructor.
Dated ski. 0041 1 100i
L
COMPLETE SPECIFICATION..
Improvements in Mechanism for Operating Doors and Gates of
Freight Elevator Wells in Manufactories.
A communication from abroad by ORION LIVINGSTON DAVIS, of Rochester, in
the County of Monroe and State of New York, United States of America,
Manufacturer and Inventor.
I, WILLIAM PHILLIPS THOMPSON F.O.S., M.LIME. of the Agenoy for
Foreign Patent Solicitors, 6 Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster and 323 High Holborn, in the
County of Middlesex, Civil Engineer, 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:-
According to this invention, a light vertical continuous shaft is provided
extending from the lowest to the highest story of the building in which the
elevator doors are to be operated, so that all the doors of a vertical series, for
instance, opening into a well may be operated by it. This shaft is rotated con-
tinuously in one direction by some simple means, as a belt or cog wheels connecting
it with some convenient part of the power shafting in the building and indepen-
dently of the action or movements of the car, the shaft being outside of the well
and near the doorways therein.
At each story of the building a friction wheel about three inches in diameter is
secured rigidly to this shaft for operating the door of that story, the friction wheel
being located a short distance above the top of the door. The mechanism is the
same for each of the doors of the various stories.
The door to be operated is usually supported upon traverse rollers resting on a
track in a manner that is common and provided at its upper edge and near its
..respective vertical edges with two arms which hold two parallel belts or straps,
These belts are horizontal as to their points of suspension but placed to stand
edgewise one on either side of the friction wheel and separated by a distance a
little greater than the diameter of said wheel.
Just outside of and in contact with each belt is a vertical roller held by a
horizontal sliding piece beneath the wheel, the axes of the two rollers, the friction
wheel and the shaft being in the same vertical plane, transverse to the plane of the
door. The sliding piece is fitted to slide horizontally upon a bed-piece rigid with
a wall or part of the well, the motions of the sliding piece being in the line of the
.plane just mentioned so that the rollers are in any case carried one directly toward,
and the other directly from, the friction wheel.
Now, if the sliding piece be moved in either direction, it will cause one or the
other of the idlers to press its contiguous belt against the revolving wheel and, by
friction, move the belt, and, consequently, the door. By shifting the sliding piece
in the opposite direction to bring the other belt against the wheel, the door will be
moved in the opposite direction, the shaft and the friction. wheel revolving con-
tinually in one direction.
A roller is attached to the car and a vertical cam lever is held in place near each

page_text: door to be operated by said roller, as the car moves along the well, the cam lever
being connected with the sliding piece for the purpose of shifting the latter, as
above described.
In order that the said invention may be more fully understood and readily carried
into effect, the drawings hereto annexed will now be described and the parts
therein shown and the manner of their construction and operation pointed out; in
which
Figure 1 is a plan of the essential parts of the mechanism for operating a doør
at the left side thereof.
Figure 2 is a similar plan of the parts at the right side of the door, the latter
having been moved to the left.
Figure 8 is a plan of a bed-piece for holding the sliding piece for moving the
belts.
Figure 4 is a plan of said sliding piece.
Figure 5 is a section taken on the dotted line 5 5 in Figure 1, and viewed as
indicated by the arrow pointed thereon.
妻
Figure 6 is a transverse section of the ledge holding the bed piece and other
parts, taken on the dotted line 66 in Figure 1, and viewed in a direction opposite
to that in which Figure 5 is seen,
!
Figure 7 is an elevation of the cam lever and associated parts seen as indicated
by arrow 7 in Figure 5.
Figure 8 is a front elevation of a door with parts of the operating mechanism,
the door being closed.
;
The first seven figures are drawn to a scale one third of what is preferred to
be the working size, and Figure 8 drawn to a scale of one-twelfth of the working
size.
Referring to the drawings, H is the interior of the elevator well and I portion
of the wall thereof.
The vertical operating shaft A for the doors is made of such a length as to pass
by all the doors arranged in a vertical tier. This shaft is placed without the well
and near the doors to be operated, preferably enclosed in a hollow post L and
revolved by an ordinary belt and pulley B, Figure 8, from some convenient
revolving shaft in the building, or by means of other gearing connecting it with tho
power shafting of the building.
C is one of the doors of the well and at a certain point above the level of its
upper edge is a friction wheel D secured to the shaft by binding screws or other
simple means. A Bed piece E shown separately in Figure 3 is secured in 'a
horizontal position beneath the friction wheel to the front wall of the well or some
part of equal rigidity in position to have the shaft pass through an opening in
its centre. This bed piece may be constructed with an upwardly projecting hub a
to form a bearing or support for the shaft.
-
bis a sliding piece shown separately in Figure 4 fitted to move along bearings
on the bed-piece, formed with an oval opening at its centre to pass over the hub a.
The form of bearings between the parts E and b is unimportant, provision being
made simply to admit of a sliding motion of the latter upon the former. The bed-
piece may, if desired, be made in the form of a letter H, and the sliding piece is
formed with projecting parts to enter the end openings cc therein. This sliding
piece is provided with two vertical idling rollers d d one on either side of, and level
with, the friction wheel, the axes of these rollers and the wheel being parallel and
in a vertical plane at right angles with the plane of the door C.
fare drag belts preferably made of leather, canvas or similar material and
are held one on either side of the friction wheel to be acted upon by it to move
the door. The belts are conveniently held by arms secured rigidly to the
door by iron straps hh, Figures 6 and 8, one arm being near each vertical
edge of the door. As shown, the arms hold prismatic blocks of woodi i to the
vertical edges of which the respective belts are secured by simple fastenings.
These arms overhang the vertical edges of the door and the drag belts are
L

page_text: ..stretched between them; and the arms being formed with longitudinal slots k
they may be moved in directions away from each other to tighten the belts.
The door is, supported by rolling hangers 6 6 resting on a horizontal track, e¹
held on a ledge over the door and rolls toward the right when closed and
toward the left when opened. When the door is closed, the left hand arm gis
near the shaft A. as shown in Figure 1, and when the door is open, the right
hand arm is near the shaft as shown in Figure 2, these arms alternately
..approaching and receding from the shaft as the door is moved one way or the
other. By moving the sliding piece forward or backward one or other idling
roller is caused to press the drag belt near it firmly against the friction wheel,
thus causing the door to be moved in one direction or the other as the case may be.
A vertical cam lever F, Figures 1 and 5, is held within the well upon a
pivot a in position to indirectly actitate the sliding piece b; a vertical spring
bar being interposed between it and said sliding piece as shown. This spring
bar is secured at its upper end to the sliding piece by a simple bolt and held at its
lower end by a pin. Normally, the cam-lever stands inclined slightly in a direction
away from the shaft in the position shown in full lines, Figure 5, resting, for a stop
at e, against a wall of the hollow post L. In this position, the swelle of the lever
will be in the way of a roller a projecting from the car Gas the latter moves up or
down within the well. Now, if the car be ascending, for instance, the roller n will
encounter the lower inclined part of the swell of the lever and, as the car continues
npward, cause the lever to press against the spring bar and thus shift the sliding
piece in a manner to cause the inner roller d to press the inner drag belt f¹ against
the friction wheel. The result of this is that said drag belt and the door are moved
to the left to open the passage way into the well.
These forced positions of the cam lever and the spring bar are shown in dotted
lines in Figure 5, which correspond with the position of the sliding piece with its
rollers and other parts shown in dotted lines in Figure 1, and in full lines in
Figure 2.
The spring bar being flexible and elastic causes the belt to be held steadily
against the friction wheel notwithstanding the fact that the car, as it moves along
in the well, is liable to shake or jog in a sidewise direction toward or from the cam
lever and thereby exert an unsteady pressure against the latter..
When the car passes on, the sliding piece, spring-bar and cam-lever are
respectively thrown back to their normal positions by a laterally acting spring p,
Figures 1 and 2, pressing against the extended pin o of the inner roller d or some
-other convenient part of the sliding piece. Also, when these parts are thus
.returned to their normal positions, the position of the sliding piece is such that the
-outer roller d presses the outer belt f against the friction wheel which causes the
door to be closed. Thus it will be seen that the normal positions of the various
alternately acting parts correspond with a closed position of the door.
The car has nothing to do with the closing of a door except to clear itself from
the cam lever by proceeding on its way, leaving the closing spring p to act upon
the parts. The actions of the two springs and p. cause the belts respectively to be
held against the friction wheel with a yielding pressure.
Recesses are formed in the inner faces of the respective belts as shown in
Figures 1 and 2, so that when, in any instance, the door becomes fully closed or
fully opened, contact between the friction wheel and the belts will be broken; the
wheel then becoming temporarily inactive although continually revolving.
The sliding piece coming in contact with the hub a of the bed-piece, as shown, in
Figure 5, when shifted by the spring p, limits its motion in that direction so that
the breaking of the contact just mentioned. between the belt f and the friction
wheel is rendered possible and certain, and a similar contact between the sliding
piece and bed-piece when the former is moved in the opposite direction by the cam
Jever renders the breaking of the contact described between the belt and the
friction wheel certain..
:.
The sliding piece is further provided with a rigid studs, Figures 1,and 7, and a

page_text: :
spring eatch or hook tis secured to the left hand arm ÿ in position to catch onto
the stud when the door is moved to the right and closed, thus serving to hold the
door in that position against any effort to open it by hand. When however the
sliding piece is shifted to the position shown by dotted lines in Figure 1 by
the action of the car, the stud becomes relieved from the spring catch and the
latter, with the arm, is permitted to move freely away to the left as the drag
belt is moved by the friction wheel to open the door.
It is not essential to this invention whether the part w (Figure 5) held by the car
to actuate the cam lever be a röller, for it may be merely a projecting boss of
suitable size and form, though a rolling contact with the lever is desirable.
This actuator is held by the oar in any convenient manner so as to be thrown
in the way of the swell of the cam lever, or withdrawn so as to pass the successive
cam levers without touching them.
注
The actuator as shown is a wheel secured by means of holding jaws w to a hand.
lever u pivoted to some convenient part of the ear so as to swing forward or
backward from the cam lever, A simple latch a pivoted to the side of the hand
lever to move in a vertical plane and riding upon a stud y rigid with the car,
serves to bold the hand lever in its forward position in which the wheel n is caused.
to encounter the swell of the cam lever as the car comes along. A tooth z,
'Figure 5, of the latch drops beside the. stud when the hand lever is pushed out,
thus holding the latter in position. When it is wished to allow the car to pass.
any of the doors without opening them, the attendant lifts the latch sufficiently
to allow the tooth to clear the stud, and then immediately the hand lever is thrown.
back by a spring pressing against it to the position shown by dotted lines in the
figure. This carries the wheel n out of the way of the various oan-levers so that
all doors are passed without being opened. The study also acts as a stop for the-
backward movement of the hand lever caused by the action of the spring v.
When the belts fƒ are made of leather or canvas, one or both of them are bent.
as shown in Figures 1 and 2, against the friction wheel by the shifting of the
sliding piece 6 above described. In case they are made rigid, as, for instance, of
stiff iron, they can be shifted bodily sidewise against the friction wheel by means.
similar to those employed to shift the sliding piece. In this case, the prismatic
blocks instead of being rigid with their respective arms g g are allowed to slide-
along the channels formed therein, the holding bolts g h at the same time moving.
in slots kk. When such rigid iron bars are employed, the friction wheel is
covered with leather or some similar material to augment the friction between it.
and the bars.
Or, again, when for convenience of construction or adaptation it becomes.
desirable, a single rigid bar only may be employed instead of two, such bar being
placed centrally between two friction wheels, turning in the same direction, that is
to say, so that the peripheries of the wheels shall pass the bar in opposite directions,
the wheels being placed a little further apart than the thickness of the bar. As
the bar is moved against one or the other of the wheels, it, with the door, will be
carried in one direction or the other as the case may be. In this construction, Bs.
in the other, the bar may be shifted against the wheels or the wheels may be shifted
against the bar, this being a mere matter of convenience in construction and left to.
the mechanic, both being comprehended in the invention herein shown and described.
Also said rigid bar or bars may be formed with cogs along their vertical faces.
instead of with friction surfaces, the periphery of the wheel or wheels being also
"formed with cogs to engage said cogs of the bars; the propriety of forming the
contact parts smooth or with cogs being also determined by the mechanic or
constructor.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is
1. In a device for operating the doors or gates of elevator wells, a vertical shaft.

page_text: extending by or near a door or a series of doors of a well with independent
mechanisms connecting each of the doors with the shaft, the latter being revolved
by means other than, and independent of, the movements of the car.
2. A device for operating the doors of elevator wells, consisting of a shaft near
the doore and parallel with the axis of the well and revolved continually in one
direction by means independent of the movements of the car, the doors being each
connected with the shaft by independent mechanisms, each of the said mechanisms
being arranged to be thrown into action by the passing car.
3, A device for operating the doors of elevator wells, consisting of a revolving
shaft near the doors to be operated, and parallel with the axis of the well, said
shaft being supplied with a friction wheel for each door, each of the doors having
carrying arms to hold horizontal parallel belts or bars one on either side of the
friction wheel to be acted upon by it, and means for pressing the belts or bars
alternately against the friction wheel.
4. A device for opening and closing the doors of elevator wells, consisting of a
vertical revolving shaft having friction wheels to operate the respective doors,
each door having rigid arms and parallel belts held by said arms one on either
side of the friction wheel, a horizontal sliding piece carrying vertical idling
rollers for the belts one on the outside of each belt, the axes of said rollers and
the friction wheel being parallel and in a vertical plane at right angles with the
plane of the door, and a cam lever to be acted upon by the car to shift the said sliding
pieces in order to bring a belt in contact with the friction wheel, and an elastic bar
or spring forming a connection between the said cam lever and the said sliding
piece, so the belt may be held against the friction wheel by a yielding pressure.
5. Mechanism for operating the doors of elevator wells, the same being a
vertical revolving shaft near the doors provided with a friction wheel near each
door, each door carrying a pair of parallel belts one on either side of and near the
friction wheel and a sliding piece with idling rollers to alternately press said belts
against the friction wheel, each belt being formed with a recess on its inner face
near the end to relieve the contact and friction between said belt and the friction
wheel when the door is either fully open or fully closed.
6. Mechanism for operating the doors of elevator wells, consisting of a vertical
revolving shaft near the doors, provided with a friction wheel to operate each
door, the doors each having drag belts one on either side of the friction wheel, and
a sliding piece to move the belta alternately to or from the friction wheel, the
sliding piece being provided with a stud, and the holder for the drag belts near
the shaft when the door is closed being provided with a spring hook to catch onto
said stud to hold the door shut.
7. A device for operating the doors of elevator wells, consisting of a revolving
shaft carrying friction wheels to propel the respective doors, each door carrying
drag belts or bars near its associated friction wheel, a sliding piece with rollers to
present the belts alternately to the friction wheel, a cam lever to be operated by
the car to shift the sliding piece, and an independently acting spring to return the
sliding piece to its normal position.
8. An elevator shiftable door carrying a rigid bar or pair of bars smooth or
provided with teeth, extending substantially from edge to edge of the door and
parallel with the plane of the door, a revolving shaft to operate the door and a
smooth or toothed wheel or pair of wheels turned by the shaft to propel said bar
or bars in order to move the door for opening or closing the passage way into the
well.
'
E
3
1000