IMPROVEMENTS IN HYDRAULIC LIFTS
Year: 1879

page_text: LETTERS PATENT to Cyrus W. Baldwin, of Gracechurch Street, in the
City of London, for the Invention of "IMPROVEMENTS IN HYDRAULIC
LIFTS."
-
PROVISIONAL SPECIFICATION left by the said Cyrus W. Baldwin at the
Office of the Commissioners of Patents on the 10th October 1879.
CYRUS W. BALDWIN, of Gracechurch Street, in the City of London.
MENTS IN HYDRAULIC LIFTS."
" IMPROVE-
This Invention relates to improvements on the hydraulic lifts or elevators
described in the Specifications of Letters Patent granted (1) to Herbert John
Haddan on behalf of the present applicant, and dated 24th August 1877, No. 3219,
and (2) to the present applicant dated 18th July 1878, No. 2863.
The class of lifts to which my present improvements have special reference is
that described in the Specification of the second Patent above referred to, in which
a double ram or piston, operated by fluid pressure on one or both sides of the
pistons, is used in combination with an arrangement of ropes and pulleys to raise
and lower the elevator car.
This apparatus may be generally described as consisting of two vertical cylinders
mounted one above the other, each containing a piston and rod. The two pistons
are connected and work together, and the upper end of the top piston rod is
attached to a movable pulley, round which the car suspending rope or ropes pass.
These ropes are firmly secured at one end to the upper part of the lift framing, and
after passing round the movable and other pullies once, twice, or more times, and
over a wheel or drum mounted at the upper part of the framing are attached to
the car.
Two passages are made in the walls of the lower cylinder, one of which connects
the bottom of the upper cylinder with the bottom of the lower cylinder, and the
other passage connects the top of the lower cylinder with a valve chamber. The
main supply pipe is connected at one end with the top of the upper cylinder, and
at the other end with the valve chamber, and is always open; thus the cylinders
are always kept full of water.
The discharge pipe or passage from the bottom of the lower cylinder is also
connected with the valve chamber, which consists of a cylinder open at both ends.
This cylinder is fitted with a valve or valves consisting of three or more discs
mounted on a single stem so arranged as to open or close the connection between
Price 1071

page_text: two or more of the discharge and supply pipes above referred to. The disc valves
receive motion from a pinion which gears with a rack attached to the upper end of
the valve stem, and is worked in any convenient manner from the car by the
attendant.
The action of this apparatus is as follows:-Suppose the car to be at the bottom
of the building, the pistons will be at the top of the cylinders. In order to raise
the car the water below the pistons is discharged, and the pressure of the supply
accumulating above forces them down, in doing which it draws down the pulley
which pulls on the ropes to raise the car. For lowering the car the water is allowed
to pass through the passages above referred to from above the pistons to below the
pistons, the weight of the car being sufficient to cause it to descend.
As in this case the discharge of the water from the cylinder will be closed, a
circulation of water from above to below the pistons, and regulated by the disc
valves, will take place.
The sudden shutting off of the discharge by these valves to stop the car causes a
shock to the latter, and is a source of considerable danger to hydraulic elevators, as
the piston while moving quickly is brought against an immovable body of water,
and the shock thus caused strains and otherwise injures the apparatus.
It is the object of the present improvements to obviate theso disadvantages, and
otherwise to improve the working as well as to simplify the construction of this
class of hydraulic lifts.
The bottom of the valve chamber being open when the disc valves are raised, a
free discharge of the water from the bottom of both the cylinders through the
valve chamber takes place, and the sudden stoppage of this discharge is one of the
causes of the shock felt. It has been found by experiment that by throttling the
discharge to some extent this disadvantage may be partially removed. The result
may be effected by means of a conical valve which is attached to an extension of
the valve stem of the disc valves. This conical valve, which may be of any
suitable diameter according to the amount of throttle required, works in a pro-
longation of the valve chamber, an enlargement being made in the upper part
thereof to allow full space for the discharge water to pass away when the disc
valves are raised to open the discharge from the cylinder. When closing the dis-
charge by lowering the disc valves the conical valve comes first into operation, and
partially closes the discharge opening previous to the complete closing by the disc
valves. By this means the cut off is more gradual, and the shock is thereby to a
great extent prevented.
As a further improvement it is proposed to use a relief valve enclosed in a suitable
valve chamber, and connected in any suitable manner with the discharge passage in
front of the cut off valves and the main supply pipe, the effect of this valve being
to allow the escape under the unusual pressure caused by the descending piston of
a portion of the water in the discharge opening.
The pistons may also be formed with a number of holes through them. These
holes, as well as the whole of the upper face of the piston, are covered with a disc
of india rubber or other suitable material, which may be secured to the piston in
any convenient manner.
Any unusual pressure of, the water on the underside of the rubber disc, whether
produced by the closing of the valves or from any other cause, will raise the disc
and allow a portion of water to escape into the space above the piston until the
pressure below is reduced, when the descent of the piston will be arrested, and the
ascending car stopped.
Sometimes it may be necessary to connect the discharge pipe with a tank or
reservoir to receive the discharge water. In this case the closing of the valves will
cause a back rush of the discharge water against the conical and disc valves. To
prevent this a relief valve is employed, which may consist of an ordinary clack
valve placed in a valve chamber connected with the conical valve chamber by a
short pipe. This valve opens inwards to allow of the entrance of air sufficient to
fill the vacuum below the valves caused by the rushing of the discharge water.

page_text: The air thus sucked in will form a cushion to prevent the back rush of the
water.
In the Specification of the Patent dated 18th July 1878, before referred to, the
water under pressure, before entering the upper part of the lower cylinder, has to
pass from the main supply pipe through the valve chamber and into the second
passage made in the walls of the lower cylinder. This in practice has been found
undesirable, and it is now proposed to dispense with this passage and connect the
supply pipe direct to the upper end of the lower cylinder. This connection is pro-
vided with a suitable cut off valve, which may be worked either by hydraulic power
regulated by the rack of the disc valves or by the direct action of the rack. By
the opening or closing of this valve the water under pressure is allowed to enter, or
is shut off from, the lower cylinder above the piston, and one or both pistons may
be used according to the load it is desired to raise. It is however preferred that
this valve shall close automatically, and for this purpose it is provided with a
counterweight which is connected with the valve rod.
Communication between the upper and lower cylinders is effected through a valvo
so arranged that when the pressure of the supply to the lower cylinder is removed
the valve will be free to open or close; but when the supply pipe to the lower
cylinder is open, which will be the case when both pistons are working, the pressure
of the water will act on the valve to keep it closed. In the latter case, the water
from below the upper piston will escape by a circulating pipe connected with the
discharge pipe.
The disc valves are so arranged that they will, when it is desired to lower the
car, open all ports except the discharge opening from the valve chamber, and bring
the main supply pipe into communication with the discharge pipes.
The pressure of the water on the top of the pistons will be therefore removed,
and the water above and below the pistons will be balanced. Thus the weight of
the car will be not only sufficient to raise the pistons, but also to cause the circu-
lation of the water from above the pistons through the supply pipe disc valve
chamber and the discharge pipes into the bottom of the cylinders. At the same
time the circulation of the water can be regulated by the disc valves.
The supply and discharge openings in the cylinders are so arranged, and the
pistons are so formed, that should any accident occur to the apparatus the pistons
will close one or other of these openings and prevent any further working of the
apparatus.
Provision may also be made for stopping the car by working the hand rope from
the movement of the pistons instead of that of the car. Under some circum-
stances this may be of importance, as the movement of the pistons is much slower
than that of the car. This will prevent the shock occasioned by the car striking
against the stop on the rope.
A friction arrangement may be applied to the bottom of the car consisting of a
clamp or clamps so arranged and connected to the safety beam beneath the car as
to clamp the car guides. The jaws of these clamps are forced together by springs,
and are so constructed as to close and embrace firmly the guides when the car is at
rest or standing. The clamp jaws are relieved by the hand rope in connection with
the disc valves, so that when the valves are opened by the movement of the rope
the friction is removed, and the jaws are fixed simultaneously with the opening or
closing of the valves. This also has a tendency to check the velocity of the column
of water in the pipes and cylinders. The friction should be so planned as to take
action before the valves are completely closed, and to be relieved a little before the
valves are opened, that is, its action should be slightly in advance of that of the
valves.
It will be obvious that with but slight modifications the above improvements may
be readily applied to an elevator or lift worked with one piston, similar to that
described in the Specification of the Patent dated 24th August 1877 before

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Cyrus W. Baldwin in the Great Seal Patent Office on the 10th
April 1880.
CYRUS W. BALDWIN, of Gracechurch Street, in the City of London. " IMPROVE-
MENTS IN HYDRAULIC LIFTS."
This Invention relates to improvements on the hydraulic lifts or elevators
described in the Specification of Letters Patent granted (1) to Herbert John
Haddan, on behalf of the present applicant, and dated Twenty fourth August, One
thousand eight hundred and seventy seven, No. 3219, and (2) to the present
applicant, dated Eighteenth July, One thousand eight hundred and seventy eight,
No. 2863.
The class of lifts to which my present improvements have special reference is that
described in the Specification of the second Patent above referred to, in which a
double ram or piston operated by fluid pressure on one or both sides of the pistons
is used in combination with an arrangement of ropes and pulleys to raise and
lower the elevator car.
This apparatus may be generally described as consisting of two vertical cylinders
mounted one above the other each containing a piston and rod. The two pistons
are connected and work together, and the upper end of the top piston rod is
attached to a moveable pulley, round which the car suspending rope or ropes pass.
These ropes are firmly secured at one end to the upper part of the lift framing, and
after passing round the moveable and other pulleys, once, twice, or more times, and
over a wheel or drum mounted at the upper part of the framing are attached to
the car.
Two passages are made in the walls of the lower cylinder, one of which connects
the bottom of the upper cylinder with the bottom of the lower cylinder, and the
other passage connects the top of the lower cylinder with a valve chamber. The
main supply pipe is connected at one end with the top of the upper cylinder, and
at the other end with the valve chamber, and is always open, thus the cylinders
are always kept full of water.
The discharge pipe or passage from the bottom of the lower cylinder is also con-
nected with the valve chamber, which consists of a cylinder open at both ends.
This cylinder is fitted with a valve or valves consisting of three or more discs
mounted on a single stem so arranged as to open or close the connection between
two or more of the discharge and supply pipes above referred to. These disc valves
receive motion form a pinion which gears with a rack attached to the upper end of
the valve stem, and is worked in any convenient manner from the car by the
attendant.
The action of this apparatus is as follows:-Suppose the car to be at the bottom
of the building the pistons will be at the top of the cylinders. In order to raise
the car the water below the pistons is discharged, and the pressure of the supply
accumulating above forces them down, in doing which it draws down the pulley,
which pulls on the ropes to raise the car. For lowering the car the water is
allowed to pass through the passages above referred to from above the pistons to
below the pistons, the weight of the car being sufficient to cause it to descend.
As in this case the discharge of the water from the cylinders will be closed a
circulation of water from above to below the pistons, and regulated by the disc
valves will take place.
The sudden shutting off of the discharge by these valves to stop the car causes a
shock to the latter, and is a source of considerable danger to hydraulic elevators as
the piston while moving quickly is brought against an immovable body of water,

page_text: and the shock thus caused strains and otherwise injures the apparatus, and
endangers the safety of the occupants of the car.
It is the object of the present improvements to obviate these disadvantages, and
otherwise to improve the working as well as to simplify the construction of this
class of hydraulic lifts.
In the accompanying Drawings Fig. 1, Sheet I., is a side elevation of the double
cylinder arrangement constructed according to my former Patent, and shewing part
of my improvements connected therewith; Fig. 2 is a sectional elevation on the
line x, x, Fig. 1, and Fig. 1 is a general view in elevation of my improved lift
apparatus as applied to a five-storied building. A and B are two vertical cylindora
placed one above the other, and each containing a piston A', B¹, and piston
rod A, B. The two pistons A', B¹, are connected together in any suitable
manner, and the piston rod A² is connected with the car in the manner described
in the Specifications of the Patents above referred to.
The cylinders A and B are separated by a partition, the part C of which is
horizontal, and the part C' vertical. The part C carries a stuffing box for the
piston rod B, and in the part C¹ is made an opening which forms the only direct
means of communication between the cylinders A and B. This opening is closed
by an ordinary clack-valve C³ (see Fig. 3, Sheet II)., which when water under
pressure is shut off from the cylinder B is free to open or close, but when the water
under pressure is turned on the valve is maintained shut by such water under
pressure.
D is the supply pipe in connection at D* with a cistern or the city mains, and
opening at its upper end into the cylinder A, and at its lower end into the valve
chamber E; F is the discharge pipe from the cylinder B into the valve chamber.
This valve chamber E contains a series of disc valves, the construction and working
of which are fully described in the Specification of my Patent of July Eighteenth,
of One thousand eight hundred and seventy eight before referred to.
E is a pulley suitably mounted, and round which passes the endless cord (shewn
in dotted lines Fig. 1a) for stopping and starting the apparatus. This cord passes
through the car and round pulleys on the upper part of the lift framing, and is
worked by the attendant in the car. On the axle of the pulley E' is a pinion E,
which gears with a rack Es attached to the stem of the disc valves, and by which
they are worked,
In the Specification of this Patent the water under pressure before entering the
upper part of the lower cylinder B is described as having to pass from the main
supply through the valve chamber E, and into a passage made in the walls of the
lower cylinder. This in practice I have found undesirable and inconvenient, and
I now dispense with this passage, and I take the supply of water for the cylinder B
direct from the supply pipe D, the connection being provided with a cut off valve G
to be hereafter described. The discharge passage from the upper cylinder, which
in the former case was made in the walls of the lower cylinder, I also dispense
with, and in place thereof I employ an external pipe H (see Fig. 1), which I connect
at its upper end in any convenient manner to the cylinder A, and at its lower end
with the discharge passage F of the cylinder B. By thus arranging these passages
I am enabled to simplify the construction both of the lower cylinder B and the
valve chamber E, as in the latter I dispense with one of the openings into the
valve chamber.
The supply opening D¹ in the cylinder A, and the discharge opening F in the
cylinder B, are so arranged that should any accident occur to the apparatus the
pistons will partially close one or other of these openings, and gradually stop
the working of the apparatus. To this end the head of cylinder A consists of a
circular box or casing I through which the piston rod A² passes. The top of the
box I is provided with a stuffing box for the piston rod, and in the bottom of the
box I is a circular opening to receive a circular plug J of somewhat less diameter
than the opening, and mounted in any convenient manner adjustably on the piston

page_text: rod A² immediately above the piston. The supply pipe D is connected to the side
of the box I. The bottom of the cylinder B is closed by a similar circular box or
casing I. In this case however no stuffing box is required, as the piston rod does
not descend through it, and the circular opening is made in the top of the box I' to
receive a circular plug J', also of less diameter than the opening I', secured in any
convenient manner adjustably to the underside of the piston B'. The discharge
opening F is at the side of the box.
It will thus be seen that should the piston A¹, from any accidental cause, rise to
the top of the cylinder A, so that the plug J enters the opening in the bottom of
the box I, the discharge of water from the top of the cylinder A will be nearly
entirely cut off, and the further working of the apparatus will be retarded, while
the striking of the piston against the cylinder head will be prevented by the cushion
of water which will be formed above the piston.
In like manner the plug J' entering the opening in the box I' will partially close
the discharge of water from the bottom of the cylinder B with results similar to
those indicated above.
or J to enter
I would here remark, that when in ordinary work it is not proposed that the
pistons should rise or fall to such an extent as to cause the plugs
the openings in their respective boxes I and I'.
The valve connection G between the supply pipe D and the cylinder B for
regulating the supply of water to the cylinder B is shewn drawn on an enlarged
scale at Figures 3 and 4, Sheet II., in which Fig. 3 is a partial cross section taken
in the line y, y, Figures 1 and 2, and Fig. 4 is a vertical section through the valve.
G is a hollow casting or valve case which is bolted or otherwise secured to the
supply pipe D and to the cylinder B; in this casting is formed an annular passage
a which is open to the interior of the casting, and is in connection with the opening
into the cylinder B. The opening of this passage a into the casting G is closed by
a piston valve b mounted on the piston rod c, and which may be worked either by
hydraulic power or mechanically from the valve chamber E.
When hydraulic power is to be employed for working this piston the piston rod
c, which projects through a suitable stuffing box, is connected to a suitably placed
counterweighted rocking arm, the object of which is to always maintain the piston
b at its highest position and close the opening into the passage a, see Fig. 4. A
pipe in connection with the discharge opening F of the valve chamber E is secured
to the valve case G at d, and is provided with a cock which is opened and closed in
any convenient manner from the valve stem of the disc valves E. When the cock
is opened the water in the pipe and under the piston b will escape into the discharge
F, and the pressure of the supply water from the pipe D will force down the piston
b and open the passage a, thereby allowing water to flow into the top of the
cylinder B.
In order to prevent the two sudden descent of the piston 6 when the pressure is
exerted on its upper surface I make two or more holes b¹, 61, in the piston, which
will allow some of the water to pass through to the underside, and thus form a
temporary cushion before it escapes down the pipe into the discharge F. When tho
cock is closed the water will continue to flow through the openings b¹, b¹, in the
piston until the pipe d is full, when the column of water in the pipe will neutralize
the pressure of the water on the piston b, which will be caused to rise slowly into
the position shewn at Fig. 4 by the action of the counterweight.
When mechanical means is employed for opening the passage a I connect the
piston rod c by means of a link rod c¹ to one arm of a bell crank lever e, which is
pivotted to a bracket e' carried by the supply pipe D, see Figures 1 and 2, and on
an enlarged scale Figures 5 and 6, Sheet II., Fig. 5 being a partial cross section on
the line 2, 2, of Fig. 6, which is a front elevation. The other arm of this lever e is
provided with a pin or stud e² which works in a slotted plate fattached to the rack
Es in connection with the disc valves E.
When the pin eis in the position shewn at Fig. 2 the piston valve b will be

page_text: raised and the opening a will be closed, as seen at Fig. 4, but when, through the
rising or falling of the plate f, the pin e³ is brought past either of the inclined por-
tions to the ends of the slot (into the position shewn at Fig. 6, for instance), the
levere will be rocked on its centre and will depress the rod c, which will in turn
draw down the piston b and open the passage a.
The slot in the plate f is so arranged that the supply of water under pressure to
the cylinder B shall be cut off while the discharge opening F is closed, or when it is
desired to work with only one piston, should the load to be raised not be sufficient
to require the two pistons to be worked.
As an additional precaution the supply opening D₁ to the cylinder A may be
partially closed as the piston A¹ nears the bottom of its cylinder. This may be
effected, amongst other arrangements, by a butterfly valve h, the stem of which
projects through the walls of the casting and carries at its outer end a counter-
weighted finger. The valve h is closed by a rod h³ (secured in any convenient
manner to and descending with the piston rod A³) striking against the end of the
finger h², which rocks the valve on its centre and brings it into the position shewn
at Fig. 2, the finger assuming the position shewn at Fig. 1b.
As the rod h³ ascends with the piston rod A² it will allow the valve h to open by
the action of the counterweight.
In order to stop the ascent of the car the discharge F is closed by hauling on the
starting rope eo as to cause the disc valves to descend into the position shewn at
Fig. 2, and as there will then be no exit for the water from below the pistons the
pressure of water above the pistons will be neutralized, and the working of the
apparatus will be necessarily arrested. The too sudden closing, however, of this
discharge F by the disc valves will cause a shock or jerk to the car when stopping,
and will also tend to strain considerably the parts of the apparatus.
As a means for preventing these shocks or jerks I employ a conical valve so
arranged as to throttle to a great extent the discharge opening F¹ from the valve
chamber E. This arrangement is shewn in Fig. 2, and in enlarged sectional views
at Figures 7 and 8, Sheet I.
The bottom of the valve chamber being open when the disc valves are raised
into the position shown at Fig. 7 a free discharge of the water from both cylinders
A, B, through the passage F takes place. When only one cylinder is being used a
portion only of the water from the cylinder A is discharged through the pipe H and
passage F, the remainder passing through the valve C into cylinder B above
piston B¹, and the discharge opening F need be thus only partially opened.
The valve stem 6 of the disc valves I prolong downwards to receive a conical
valve m, which is held in the required position between a sleeve on the stem l,
and a nut m¹ screwed on the end thereof, see Fig. 7. The diameter of the valve m
will depend upon the amount of throttle it is desired to give to the discharge, but in
all cases it must be somewhat less than that of the opening F. The conical valve
works in a prolongation of the valve chamber E, an enlargement being made
therein to allow full space for the flow of the discharge water. The diameter of
this enlargement should be such that when the valve m is in the enlargement (see
Fig. 7) the area of the annular space round the base of the cone shall be equal to
the area of the opening F¹ of the part E*.
The valve m as it descends with the disc valves will gradually lessen the area of
the discharge space round the base of the cone until it enters the lower portion of
the part E, from which point the discharge space will remain the same, and the
speed of the outflow of the discharge water will be correspondingly diminished.
By this time the disc valve will have descended only about one third of the depth
of the discharge opening F, and so long as any portion, however small, of the
discharge F remains open the outflow of the discharge water will continue, but its
speed will be diminished so gradually that the final closing of the opening F will
be hardly perceived.
It will be seen on referring to the respective Figures that the disc and conical

page_text: valves are shewn in three positions. In Fig. 7 the position shewn would be that
assumed by the [valves when the car is ascending with both cylinders working, the
discharge F from the bottom of both cylinders A, B, being full open. In Fig. 2
this discharge is closed by lowering (by means of the rack and pinion, and grooved
pulley, as before described), the disc valves and the car is thus arrested in its ascent.
While in Fig. 8 the supply D is in connection with the discharge F, the valves h
and G being also open, the pressure of the water is equalized on both sides of the
piston, and the car will thus descend by its own weight, the water above the piston
A¹ being forced out of the cylinder A at D¹ into the supply pipe D, and thence
through the valve chamber E into the discharge F, and up the pipe H into the
cylinder A below its piston A'. In like manner the water above piston B¹ is forced
out through the valve G into the supply pipe D, whence it passes through the valve
chamber E and discharge F into the cylinder B below its piston B¹. The stopping
of the car during its descent is effected by raising the disc valves into the position
shewn at Fig. 2, when the connection between the openings D and F will be
broken at the same time that the discharge pipe F is closed.
As an additional precaution against the occurrence of the shocks or jerks to the
car I make the pistons A¹ and B₁ hollow to allow the water under any unusual
pressure to pass through them from below to above the pistons. The manner in
which I construct my pistons is shewn in detail on an enlarged scale at Figures
9, 10, and 11, Sheet III., in which Fig. 9 is a plan view on the line x, x, Fig. 10,
Fig. 10 is a cross section, and Fig. 11 is a plan view of the under side of the
piston.
In these Figures the piston is formed with an annular passage i therein. A
number of circular openings are made through the upper face of the piston to com-
municate with the passage i, and a series of enlarged openings is are made in the
underside of the piston also to communicate with the passage i. The openings i,
as well as the upper face of the piston, are covered by a disc of india rubber j, or
other suitable material, which is secured to the piston by the collar j¹ and clamping
screw. is the packing which is held in place by the ring k secured to the underside
of the piston by the screws k².
Any unusual pressure of the water on the underside of the piston, whether
produced by the closing of the discharge F during the descent of the piston, or by
any other cause, will raise the disc of rubber j and allow some of the water below
it to escape into the space above it until the pressure below is sufficiently reduced
to allow the disc to shut down, when the descent of the piston will be arrested
and the ascending car stopped.
In addition to the last described arrangement, or in place of it, I make use of a
relief valve consisting, preferably, of an ordinary clack-valve enclosed in a suitable
case and opening inwards, and connected by short pipes with the discharge F in
front of the disc valve chamber E, and clutch the bottom of the supply pipe D, as
seen at Fig. 11. Any unusual pressure of water at the discharge opening F will
cause a certain portion of the water to force open the valve and pass into the supply
pipe D. The pressure of the water from the supply side will be upon the valve
and keep it down until the movement of the piston against the confined water on
the other side forces a part of such water through the valve.
Sometimes it may be necessary and perhaps desirable to connect the discharge
opening of the valve chamber E with a tank or reservoir to receive the discharge
water. In this case the closing of the discharge E will cause a back rush of the
discharge water, and a consequent hammering on the conical and disc valves. To
prevent this I employ a relief valve K, also shewn at Fig. 11ª, which may consist of
an ordinary clack or other valve opening inwards enclosed in a suitable valve box K³,
and connected to the bottom of the conical valve chamber by a short pipe K². The
operation of this valve is as follows:-The rushing out of the water will cause a
vacuum to form behind it and below the conical and disc valves. The suction
produced by the formation of the vacuum assisted by the pressure of the external

page_text: air, will raise or open the valve K and admit a sufficient quantity of air to fill the
vacuum and form a cushion which will prevent the hammering or shock from the
back rush of the water on the conical and disc valves.
In addition to the means above described for stopping the working of the apparatus,
I provide the car with a brake apparatus or friction arrangement which is worked
by the attendant in the car, and may be used on all occasions in stopping the
car.
This brake apparatus is carried by a horizontal beam which forms part of an
arrangement of safety attachment (described in the Specification of my Patent of
July Eighteenth, One thonsand eight hundred and seventy eight, before referred to)
and on which the car rests, its ends being recessed to fit onto vertical guides on the
elevator framing. This beam is supported by rods from two cross beams above the
car and to which the suspension ropes are attached, and these rods are so arranged
that should either of the suspension ropes break, the remaining rope will through a
pair of bell crank levers in connection with the rods actuate a pair of fingers or
points and cause them to enter the elevator framing, and at the same time force up
wedges between the safety beam and the guides.
This brake apparatus is shewn in side elevation at Fig. 12; in front elevation
partly in section at Fig. 13, and in sectional plan view at Fig. 14. L is the
horizontal beam, the form of which is somewhat modified in this instance, and which
cousists of two angle iron girders set apart with flanges outwards a distance equal
to the width of the guide M of the main frame, and rigidly connected together by
bolts L' or in any other convenient manner; N is a vertical angle piece which is
rivetted to the side plate N¹ and bolted to the beam L. The side plate N' is also
rivetted to the side plate N2, and they support between them the spring O and the
moveable clamping piece O¹. The spring O and the clamp O¹ are secured together
by a link 02 which is pivotted at one end to the clamp 0, and at the other end to
a lever Os. This lever Os is pivotted at one end to the side plates N1, N2, and is
connected at the other end by a link O' to a crank 05 on the rock shaft P which is
carried in bearings in bracket pieces P¹ secured to the beam L. The rock shaft P
is actuated by the attendant by means of the handle Q which is keyed on the
shaft P and projects through the floor of the car R, see Fig. 13. The pressure of the
spring is regulated by the screws 0%. In the position shewn at Fig. 12, the brake
apparatus is put on the guide M being gripped between the pieces N and O'. By
moving the handle in the direction of the arrow the shaft P will be rocked, which
will force out the lever 03 in connection with it and draw back the clamp O'.
This part of the brake apparatus it is proposed to use upon all occasions for stopping
the ascent or descent of the car or for putting on a drag when required.
It will be obvious that certain parts of these improvements are equally applicable
to hydraulic lifts constructed according to the Patent of the Twenty fourth August,
One thousand eight hundred and seventy seven, before referred to, in which only
one elevating cylinder is employed.
Having now described the nature of my Invention for " Improvements in Hydraulic
Lifts," and explained the manner of carrying the same into effect, I wish it to be
understood that under the above in part recited Letters Patent I claim,-
First. The arrangement above described for bringing the bottom of the top
cylinder into communication with the top of the lower cylinder to allow of the flow
of water from the upper cylinder to the top of the lower piston as the pistons are
making their descent.
Second. The means above described for gradually closing the discharge openings
in the extremities of the cylinders.
Third. The means above described for controlling the admission of the supply
water to the lower cylinder of the dydraulic lift.
Fourth. Throttling the discharge water preparatory to the closing of the discharge
valve, in the manner and for the purposes above set forth.
Fifth. The means above described with reference to Figures 9, 10, 11, and 11ª,
for relieving the back pressure of the discharge water.

page_text: Sixth. The employment of the valve K for admitting air to the discharge pipe,
for the purpose above described.
Seventh. The arrangement of friction brake apparatus described with reference
to Figures 12, 13, and 14, for arresting the progress of the car.
In witness whereof, I, the said Cyrus W. Baldwin, have hereunto set my
hand and seal, the Fifth day of April, in the year of our Lord One thousand
eight hundred and eighty.
CYRUS W. BALDWIN. (L.s.)