Improved Apparatus for Controlling the Descent of Lifts and Vehicles on Inclined Railways.
Year: 1899

page_text: Date of Application, 17th Aug., 1899-Accepted, 11th Nov., 1899
COMPLETE SPECIFICATION.
Improved Apparatus for Controlling the Descent of Lifts and Vehicles
on Inclined Railways.
We, JAMES GEORGE GRACEY, Roe Building, St. Louis, Missouri, U.S.A.,
Engineer, and ALFRED GFELLER, 422, Roe Building, St. Louis, Missouri, U.S.A.,
Attorney at Law, 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:―
Our invention has relation to improvements in automatic stops for elevators,
and consists in the novel arrangement and combination of parts more fully set
forth in the specification and pointed out in the claims.
In the drawings, Fig. 1 is an elevation of a portion of an elevator shaft show-
ing our invention in side elevation; Fig. 2 is a transverse vertical section on
line 2-2 of Fig. 1; Fig. 3 is a top plan view of the pump mechanism, the plat-
form of the elevator and the mounting-block by which the pump-cylinders are
carried, being shown dotted, and the vertical side timbers of the elevator-shaft
being shown in section; Fig. 4 is a longitudinal section through the several
parts shown in Fig. 3, the platform of the cage, however, being in place, the
section being on line 4-4 of Fig. 3, this view showing (as does Fig. 3) the
rock-frame tilted to a position corresponding to the open position of the air-
cocks controlling the, discharge nozzles of the pump cylinders, the cage being
in the act of ascending; Fig. 5 is a view corresponding to Fig. 4 (the cage and
shaft timbers being omitted, however) but showing the rock-frame tilted to a
position corresponding to the closed position of the air-cocks, or to that position
which is assumed by the parts when the cage is descending; and Fig. 6 is a
section on line 6-6 of Fig. 3.
The object of our present invention is to provide a passenger or freight elevator
with a pneumatic automatic stop-mechanism which will positively arrest the
drop of the cage should the cable supporting it break or give way, and which
will regulate the descent of the elevator under ordinary conditions, the maximum
speed or rapidity of such descent being determined at the outset by the engineer.
In detail the present device may be described as follows:
Referring to the drawings, 1 represents the floor of any prevailing type of
elevator cage, the latter being guided within the shaft by means of tracks or
ways 2 disposed along the side vertical walls of the shaft. In the present device
one of the tracks is in the form of a rack-bar 21 the teeth of which mesh with a
driving pinion 3 carried centrally along a transverse shaft 4 mounted in bear-
ings or hangers 5 along the under surface of the floor, the outer ends of the shaft
having secured thereto the crank disks (or arms) 6. The latter are provided with
roller-bearing crank-pins 7, which operate within the slotted heads Ŝ of the outer
terminals of the piston-rods 9 disposed parallel to the front and rear walls of
the cage, the pistons of the rods operating within the cylinders 10 of the single-
acting air pumps thus formed. The cylinders are secured by means of straps 11
to a bearing or mounting block 12 beneath the floor, the heads of the cylinders
being provided with an air inlet valve 13 as is common in air pumps of the

page_text: character here referred to. Disposed at the base of the discharge nozzle 14 of
each cylinder is an oscillating air-cock 15, the same being of the ordinary rock-
valve type with a single transverse passage or opening, the stems of the respective
cocks constituting the pivots for the rock-frame interposed between the discharge
ends of the two cylinders. The rock-frame is composed of the terminal arms or
levers 16 connected at opposite, ends by transverse cylindrical rods 17, 17' respec-
tively. Embracing loosely the upper rod 17 is one end of a shifting rod 18
guided in its movements along the base of a recess 19 formed in the bearing
biock 12, the opposite end of the shifting rod being provided with a head 20
to the upper surface of which is secured a bearing plate 21 extending beyond the
head, thereby virtually forming a shoulder 22 between the end of the head and
the under surface of the bearing plate. Mounted adjacent to the pinion 3, and
carried by the shaft 4, and in line with the shifting rod 18, is what may be
termed a sprocket disk 23, any tooth of which, as the cage is descending, is
adapted, with the rotation of the shaft 4, to strike against the shoulder 22 (the
shoulder being in reality the butt end of the head 20) pushing the shifting rod
in the direction shown by the arrow in Fig. 5, and rocking the frame 16, 17 in
the same direction, and hence rocking the air cocks 15 to a closed position, and
thus preventing the sudden discharge of the air accumulated in front of the
pistons. It is apparent that were the cage heavily loaded, or its descent too
sudden in case of the breakage of the supporting cables, the walls of the cylinders
might burst, if not sufficiently strong to resist the pressure of air thus accumu-
lated within them; and to prevent this accident we connect the discharge ends
of the cylinders by a pipe 24 provided with an air regulating discharge cock 25
(having a discharge nozzle 25) by which the rapidity of discharge of the air
which is being accumulated by the pumps may be regulated, thereby regulating
the speed of descent of the cage, whether the latter is descending under normal
conditions, or whether it is descending upon the breaking of the supporting
cables. It is of course obvious that were the walls of the cylinders sufficiently
strong to resist the accumulated air pressure within them, and no provision were
made for the gradual escape of the condensed air as herein indicated, the elevator
would simply come to a dead stop, the moment the air pressure was sufficient to
prevent the reciprocations of the pistons, or what is the same thing, sufficient
to prevent the rotation of the pinion 3 along the rack-bar 21.
After the shifting rod 18 has been pushed to close the air cocks 15 as just
described, the bearing plate 21 by which the said rod is supported at the end,
simply rides over the series of teeth with which the sprocket disk 23 is pro-
vided (see dotted position in Fig. 5).
With the ascent of the cage it is important, of course, that no resistance be
offered to the free and uninterrupted operation of the pumps, and hence it is
essential that the cocks 15 be open. The opening of these cocks at the proper
moment is accomplished as follows;-
-
Embracing loosely the lower rod 171 of the rock frame, is one end of a second
shifting rod 18' passing over and guided by a strap 24 depending from the
floor of the cage, and the opposite end of said shifting rod terminating in a
head 20 adapted to be struck by the teeth of the sprocket disc as the same begins
to revolve in the opposite direction with the upward travel of the cage. The
upward travel of the cage necessarily reverses the direction of rotation of the
pinion 3, and hence that of the shaft on which the pinion and sprocket disc are
mounted. By striking the head 201, the rock frame is oscillated in the opposite
direction, the cocks 15 are opened, and the head 20 of the shifting rod 18 is
again restored to a position to be struck by the teeth of the sprocket disc when
the cage begins to descend. The rods 18, 18' while sufficiently rigid to effect the
rocking of the frame 16, 17, as indicated, are at the same time sufficiently yield-
ing to permit the uninterrupted travel in the proper direction of the teeth of the
sprocket disc, over the heads 20, 20' and bearing plate 21, after the said frame
has been rocked to either one of its extreme positions. Thus (as seen by dotted

page_text: lines in Fig. 5) when the frame 16, 17 has been rocked to close the cocks 15, 15
the teeth of the sprocket disc ride freely over the yielding head 20 of the rod 18',
the latter acting in the nature of a spring pawi. But it is apparent that the
moment the disc 23 reverses its rotation, it will bear against the butt end of the
head 20 shifting the rod 18' in a reverse direction.
It is of course apparent that the cocks 15, 15 can be rocked to an open position
only with the upward movement of the cage, that is to say, a movement which
will reverse the direction of rotation of the pinion 3 and sprocket dise 23. The
frame 16, 17 by which the cocks 15, 15 are controlled, can however be reversed
automatically by the downward movement of the cage, just before the latter has
made its full descent. This is accomplished as follows:-
Located at the bottom of the shaft is a wedge-shaped block 30, the upper
inclined (and preferably curved) surface of which is adapted to be struck by
the rod 17 as the cage is descending. In thus striking the blocks, the rod 17
rides along the incline, and the frame 16, 17 is tilted sufficiently to rock the
cocks 15 to an open position, it being understood that the teeth of the rack-
bar 21 are discontinued at a point opposite the block 30 (see Fig. 1) in order to
permit of the free rotation of the pinion 3 in the opposite direction under the
sudden reversal of the rock-frame. For it is obvious, that were the teeth of the
rack-bar 21 continued to the full depth thereof, the engagement of the pinion 3
with said teeth would prevent the rocking of the frame 16, 17, in the reverse direc-
tion, as with the descent of the cage, the direction of rotation of the pinion would
be such as to prevent the rocking of the frame in a reverse direction.
While, as above stated, the reversal of the rock-frame 16, 17 can be effected
by the ascent of the elevator, it is preferably accomplished by the block 30
during the descent of the cage, as a sudden reversal of the rock frame, under
the circumstances, effects an almost immediate release of the air confined within
the cylinders, thereby reducing to a minimum the resistance to be overcome in
starting the elevator in an upward direction.
It is apparent that many changes might be made in the details without depart-
ing from the spirit of our invention. For example, we could substitute a different
form of air pump, or reduce or increase the number of cylinders, or provide
different means for mounting the mechanism, all of which is obvious to a skilled
mechanic. It is to be further understood that the present appliance could be
used on inclined railways, and the like.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. In a stop mechanism for elevators, a suitable air pump or pumps, discharge
nozzles leading from the cylinders thereof, cocks controlling the efflux of air
from said nozzles, and means for closing said cocks and compressing the air upon
the descent of the elevator, and thereby arresting the sudden drop of the cage in
case of accident, substantially as set forth.
2. In a stop mechanism for elevators, a suitable air pump or pumps, discharge
nozzles leading from the cylinders thereof, cocks controlling the discharge of
air through said nozzles, a drive shaft for the pumps, a rack-bar disposed along
the vertical wall of the elevator shaft, a pinion carried by the drive shaft of
the pumps and adapted to mesh with the teeth of the rack-bar, and intermediate
connections between the drive shaft and cocks for closing the latter upon the
descent of the elevator, and opening of the cocks upon the ascent of the elevator
or upon the reverse rotation of the pinion, the parts operating substantially as
and for the purpose set forth.
3. A stop mechanism for elevators comprising two air pumps having parallel-
disposed cylinders and mounted underneath the floor of the cage, a drive-shaft
for reciprocating the pistons of the cylinders, a pinion carried by the drive shaft,
a rack-bar forming one of the guides or tracks for the cage, the teeth of said

page_text: rack-bar meshing with the pinion, discharge nozzles leading from the cylinders
of the pumps, oscillating air-discharge cocks mounted in the nozzles, a rock-
frame connecting the stems of the cocks, a sprocket disc mounted on the drive
shaft, a shifting rod having one end loosely embracing the upper portion of the
rock-frame, the opposite end or head of the said rod being adapted to be struck
by the teeth of the sprocket disc upon rotation of the pinion in one direction, a
bearing plate carried by the head of the shifting rod and adapted to ride over
the sprocket disc, a second shifting rod having one end loosely embracing the
lower portion of the rock-frame and having a head adapted to be struck by the
teeth of the sprocket disc upon rotation thereof and the pinion in the opposite
direction, whereby the cocks are closed upon the descent of the elevator, and
opened with the ascent thereof, and an air cock for regulating the escape of air
compressed during the descent of the elevator, and hence regulating the rapidity
of the descent of said elevator, substantially as set forth.
4. In a stop mechanism for elevators, an air pump or pumps, a rock-frame,
air-cocks actuated by the frame, a rock-bar disposed along the vertical wall of the
elevator shaft, a pinion carried by the drive-shaft of the pumps, and meshing
with the rack-bar, intermediate connections between the drive-shaft and rock-
frame for rocking the latter in one direction during the descent of the elevator,
and a block located at the bottom of the elevator shaft and adapted to be struck
by the rock-frame during the descent of the elevator whereby the frame is
rocked in the opposite direction, the teeth of the rack-bar being discontinued
at a point opposite the block in order to permit the reverse rotation of the
pinion with the rocking of the frame in the opposite direction, substantially as
set forth.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and 25, Cross Street, Manchester, Agents.