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Патент USA US3020902

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Feb. 13, 1962
D. J. ARBOGAST EI'AL
3,020,892
CONSTANT FLOW VALVE ASSEMBLY
Filed Nov. 4. 1959
2 Sheets-Sheet 1
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INVENTORS
LAWRENCE F. JASEPH
DUANE J. ARBOGAST
BY
WKQWH
ATTORNEY
United States Patent 0 rice
3,020,892
Patented Feb. 13, 1962
1
2
3,020,892
Also, in the co-pending application, Serial No. 817,358,
CONSTANT FLOW VALVE ASSEMBLY
Duane J. Arbogast, Shelby County, and Lawrence F.
Jaseph, Memphis, Tenn., assignors to Dover Corpo
ration, Washington, D.C.
Filed Nov. 4, 1959, Ser. No. 850,958
17 Claims. (Cl. 121-464)
?led June _1, 1959, by Lawrence F. .laseph, one arrange~
ment of a valve assembly for overcoming the above-men
tioned di?‘iculties is disclosed. However, the present
invention provides a compact and ef?cient valve assembly
that is vastly improved in operation over that shown in
said Patent No. 2,785,660 and said application, Serial No.
817,358. In the device of said application, when a large
The present invention relates to a constant flow valve
volume of ?uid is passed therethrough, the greater part
assembly, particularly adapted for use in hydraulic eleva 10 of the pressure drop occurs in the input throttling valve,
tor systems for maintaining a constant lowering speed
designated at 80 in said application; and the drop through
of the elevator car regardless of load variations in the
the
selectively controlled throttling valve, designated as
car.
at 115 in said application, is, in fact, regulated to a
Hydraulic elevators, in their modern form, are com
?xed
value. Under these conditions, pronounced tur
monly equipped with a jack cylinder and an elevator car 15 bulence and eddying occur in the ?uid downstream of
supporting plunger reciprocable therein. For raising the
elevator car, hydraulic ?uid is supplied under pressure
to the jack cylinder by means of a pump, and for lower
the input throttling valve, and the pressure obtained from
a tap such as at 153 in said application is variable and
uncertain. A sufficient length of straight pipe or a baf?e be
ing the car, the hydraulic ?uid, which is under pressure
tween the said input throttling valve and said controlled
due to the supported weight of the plunger, the elevator 20 throttling valve would steady this flow, but either of these
car, and its load, is allowed to return from the jack cyl
would defeat the achieving of compactness. The pres
inder to a reservoir through valve means. It is towards
sure difference between chambers 91 and 57 of said ap
the improvement of said valve means and its relationship
plication is utilized to cause opening of said controlled
to the hydraulic elevator system that the present inven~
throttling valve, and since this pressure difference is regu~
tion is particularly directed. In the typical hydraulic 25 lated to a relatively small value, it is often di?icult to get
elevator system of today, said valve means comprising an
sufficiently rapid opening motion.
electrically controlled lowering valve, in which system the
The device of the present invention overcomes both
speed of the descent of the elevator car varies with the
of the above-mentioned disadvantages in the device of
load therein, with heavier loads producing faster speeds
said application by providing a unitary valve assembly
through an increase in the volumetric rate of ?uid ?ow 30 in which the selectively controlled throttling valve is
from the jack cylinder through the lowering valve to
the reservoir. In such a system, the speed of downward
travel varies nearly as the square root of the load. Since
the useful load on a passenger elevator may easily exceed
the dead load, the maximum load speed will exceed the
empty car speed by forty (40%) percent or more. This
condition is aggravated in certain higher rise plunger hy
draulic elevator installations where the pressure and
power required is reduced by partially counterweighting
located in the assembly upstream of the regulator valve
so that the turbulence caused by the regulator valve does
not effect the controlled throttling valve and the con?
trolled throttling valve operates more smoothly than the
device in said application. In the present invention rather
than regulating the pressure in the intermediate chamber
between the two valves to a substantially constant pres
sure as was the case in the device of said application, the
regulator valve, which is located downstream of the con’
the weight of’ the car and plunger, in which case, the ratio 40 trolled throttling valve, regulates the pressure in the
of load borne by the plunger with loaded car to that with
intermediate chamber to such a value that the pressure
empty car is increased, and corresponding lowering speeds
may well vary by a factor exceeding two.
An accom
drop through the controlled throttling valve is substantially
constant for any given opening of the controlled throttling
valve. In other words, with any given opening of the
controlled throttling valve, as the pressure in the input
to the controlled throttling valve varies, the effective back
in Patent No. 2,355,164, issued to Lawrence F. Jaseph on
pressure on the controlled throttling valve is varied by
August 8, 1944.
the regulator valve to give a constant drop through the
In years past, the prob‘em mentioned above, of the
controlled throttling valve, thereby producing a constant
variation in speeds due to load variations was not quite so 50 volumetric ?ow through the controlled throttling valve
pronounced as it is at present, since the car speeds of
and the valve assembly as a whole.
'
panying difficulty is encountered in that the distance
traveled during stopping varies somewhat with speed,
though this is partly overcome by the means disclosed
hydraulic elevator systems were not nearly as fast as
those of today. For example, in years past, elevator
speeds of ?fty (50) feet per minute were common, where
One of the objects of the present invention is to provide
a compact and smoothly operating valve assembly for
controlling the lowering speed of elevators.
as, today, speeds of one hundred seventy-?ve (175) feet 55 A further object is to provide a unitary lowering valve
per minute are common. Thus, with a no-load speed of
assembly including a selectively controlled throttling valve
?fty (50) feet per vminute, a forty (40%) percent in
and a regulator valve so arranged that there is rapid and
crease in speed due to a ‘full load would not be so notice
positive opening and closing motion of the selectively con
able since seventy (70) feet per minute would be maxi
trolled throttling valve.
mum with a difference of only twenty (20) feet per min 60
A further object is to provide an improved arrange
ute between no load and full load speeds. In contrast to
ment of the parts of such a valve assembly in which the
this, with a no-load speed of one hundred seventy-?ve
regulator valve is Located downstream of the controlled
(175) feet per minute, a forty (40%) percent increase
valve so that turbulence caused by the regulator valve is
in speed due to a full load would be quite objectionable
not transmitted to the controlled valve, and a vastly
since there would be a two hundred and forty-?ve (245) 65 improved valve is obtained.
feet per minute maximum and a seventy (70) feet per
A further object is to provide improved means for
minute difference.
In Patent No. 2,785,660, issued March 19, 1957, to
Lawrence F. ,laseph, one means was disclosed for over
controlling the lowering speed of a plunger type hydraulic
elevator or like hydraulic device so that the speed of
descent thereof will be substantially constant regardless
coming the afore-mentioned difficulties of varying speeds 70 of normal load variations.
and varying stopping distance with variations in car loads.
A further object is to provide ,means for assuring
3,020,892
the distance traveled during the closing of the valve
assembly will be uniform as the load varies.
A further object is to provide means for eliminating
all leakage from the ?uid passage connected to the ele
vator jack when the latter is stopped.
A further object is to provide a unitary compact valve
assembly comprising a controlled valve means for selec
tively varying the effective size of an opening, means for
introducing ?uid to said opening at various pressures, and
means for regulating the back pressure on said opening
so that the drop in pressure through said opening is sub
stantially constant for any given effective size of said
4
rate of ?ow of the ?uid through the lowering valve, and
thus, an increase in the lowering speed and stopping dis
tance of the elevator car.
The means by which the pres
ent invention overcomes these di?'iculties will be apparent
from the following detailed description of the preferred
embodiment of valve assembly 11 and its relationship to
the elevator system.
Valve assembly 11 includes a hollow valve body 47,
including a ?rst partition 49 and a second partition 51
provided in the interior of the valve body to establish
an inlet chamber 53, an intermediate chamber 55, and
an outlet chamber 57. First partition 49 separates inlet
chamber 53 and intermediate chamber 55, and also, for
a portion, separates inlet chamber 53 and outlet chamber
opening whereby the volumetric ?ow through said open
ing is constant for any given effective size of said opening.
A further object is to accomplish the foregoing objects 15 57. Second partition 51 separates intermediate chamber
in a simple, economical and highly et?cient manner.
Other objects and advantages will become apparent
from the following description taken in conjunction with
the accompanying drawings, wherein:
55 and outlet chamber 57. Inlet chamber 53 and outlet
chamber 57 open downwardly through valve body 47 at
inlet opening 59 and outlet opening 60, respectively.
Chambers 53, 57 are respectively in communication with
FIG. 1 is a diagrammatic view of a hydraulic elevator 20 passages 27, 43 through openings 59, 60 and through
system showing the principal components thereof, includ
ing the valve assembly of the present invention.
FIG. 2 is a cross-sectional view of said valve assembly,
on a larger scale than FIG. 1, and taken as on a vertical
openings 61, 62, which latter openings are respectively
provided at the ends of passages 27, 43.
Valve body 47
is positioned with opening 59 being in alignment with
opening 61 and opening 60 being in alignment with open
plane through the middle of the valve assembly with 25 ing 62, as best shown in FIG. 1, and is held in such a
position by a ?ange 63 at the lower end of the valve body,
certain parts being shown in elevation and certain parts
which ?ange is secured by bolts 65 or the like to a corre
being broken away for purposes of clarity.
sponding ?ange 67 encompassing openings 61, 62. From
FIG. 3 is a fragmentary cross-sectional view of a modi~
the foregoing, it will be understood that inlet chamber
?ed arrangement of the adjusting means of the valve
53 is substantially in free communication with the interior
assembly.
of jack cylinder 17 whereby the pressure in the inlet
FIG. 4 is a fragmentary cross-sectional view similar to
chamber is substantially the same as that in the jack
FIG. 2, but showing an alternate embodiment of the
cylinder. Also, outlet chamber 57 is in substantially free
lower part of the valve assembly.
communication with the reservoir 39 through passage 43
Referring now to the drawings in which the various
35
and conduit 41.
parts are indicated by numerals, the typical hydraulic ele
First partition 49 is provided with a cylindrical open
vator system, shown in FIG. 1, with which the valve
ing 69 therethrough adapted to permit ?ow of hydraulic
assembly 11 of the present invention is adapted to be
?uid from inlet chamber 53 to intermediate chamber 55.
used, includes a jack 13, having a plunger 15 reciprocally
A selectively controlled throttling valve 71 is provided
mounted in a jack cylinder 17, which is adapted to be
buried in the ground or otherwise ?xedly supported. 40 in valve assembly 11. The controlled throttling valve 71
and its associated parts are preferably constructed simi~
An elevator car 18 is supported by plunger 15 adjacent
lar to the lowering valve of Jaseph Patent No. 2,355,164,
the upper end thereof and is provided with the usual
previously referred to. The following general descrip
guideways, not shown. At the upper end of cylinder 17
tion of valve 71 will suffice, since a more detailed descrip
is provided the usual guide 19 attached by bolts or the
like to cylinder 17, and suitable resilient packing means 45 tion may be obtained by referring to said Patent No.
2,355,164. Valve 71 includes a throttling valve member
indicated as at 21 seals the sliding contact between plunger
73 cooperating with opening 69, and includes a disc 75
15 and guide 19. In addition, a gland 23 adjustably com
and wings 77 extending from the disc, and which wings
presses packing means 21 and is secured to guide 19 as
have shaped notches 79 therebetween. Disc 75 is pro
by screws or the like. A ?uid conduit 25 communicates
at one end with the interior of jack cylinder 17 and is 50 vided with a beveled seat 81 ?tted ?uid tight to a corre~
sponding seat at the end of opening 69. Wings 77 ?t
branched adjacent the opposite end with one branch or
closely in opening 69 and notches 79 provide ?uid passage
passage 27 extending to valve assembly 11 and the other
ways when valve member 73 moves to the right, as viewed
branch 29 extending to a power unit 31, which includes
in FIG. 2. A piston 83, which is concentric with valve
a hydraulic ?uid pump 33, preferably of the constant
displacement type; a prime mover 35, as an electric motor 55 member 73 and substantially greater in cross-sectional area
than opening 69, is rigidly connected to disc 75 by a
or the like; and a drive-belt 37. Additionally, the hydrau
lie system includes a reservoir 39 for hydraulic ?uid, a
stem 85, and is slidably mounted in a cylinder 87 pro
conduit 41 leading from reservoir 39 to pump 33 and a
vided in valve body 47. Cylinder 87 extends through
passage 43 leading from valve assembly 11 to conduit 41.
the wall of the valve body 47 where it is closed off by
For raising car 18, hydraulic ?uid is supplied under 60 a cover 89 mounted on the valve body as by bolts 91.
pressure to jack cylinder 17 by means of pump 33. A
The right-hand edge of piston 83 is formed helically, and
check valve 45 is provided in the system between branch
is also notched to receive a transverse bar 93, the center
29 and pump 33 to prevent reverse ?ow through the pump.
For lowering car 18, the hydraulic ?uid, which is under
pressure due to its supporting the weight of plunger 15,
elevator car 18 and the load therein is allowed to return
to reservoir 39 through the valve assembly 11 of the
of which engages a slot 95 in an adjusting screw 97 that
is threaded into cover 89. A handle 99 is ?xedly mounted
on the end of screw 97 so that by turning the handle,
adjusting screw 97 is turned to rotate piston 83. A
From a consideration of the above general description
spring 101 biases piston 83 to the left or closed position,
as viewed in FIG. 2, and keeps bar 93 in slot 95. A
the instant pressure to the lowering valve would increase,
Thus, the cut-off point of passage 103 may be adjusted
present invention.
of an elevator system, it will be understood that in car 70 passage 103 is communicated at one end to the interior
of cylinder 87 through a hole in the wall of the cylinder,
elevator systems of this type, in which a conventional
which hole is so positioned that it will be covered or cut
lowering valve was used in the system in place of valve
off by piston 83 after a partial right-ward motion thereof.
assembly 11, as the load increased in the elevator car,
which, in turn, would cause an increase in the Volumetric 75 by rotating piston 83, as above described to cause the
3,020,892
6
helical edge of the piston to cut off the passage at vary
ing points in the travel of the piston.
seat 161 provided in ?rst partition 49. Beveled seat 161
and beveled portion 159 are ground to ?t ?uid tight so
that when second piston member 157 is seated, as shown
_
The chamber 105 established in cylinder 87 by p‘ston
83 is connected to inlet chamber 53 by a conduit 107,
an adjustable restriction valve 109, and a conduit 11.1.
Chamber 105 may also be put in communication with
in FIG. 2, there is no ?uid escape through bore 155
from inlet chamber 53.
A stem 163 is rigidly connected adjacent one end to
second piston member 157 centrally thereof and is rig
idly connected adjacent the opposite end to throttling
intermediate chamber 55 through an adjustable restric
tion valve 113, a magnetic valve 115 and a conduit 117.
If des'red, rather than being connected into intermedi
member 131 adjacent the central portion of c'rcular wall
.ate chamber 55 as shown in FIG. 2, conduit 117 may 10 133. Likewise, a second stem 165 is rigidly connected
alternately be connected to outlet chamber 57 as shown
to throttling member 131 adjacent the center portion of
circular wall 133 and on the opposite side from stem
in FIG. 4, so that the full pressure differential between
163. The opposite end of second stern 165 from cir
cular wall 133 is rigidly attached to ?rst piston member
a more rapid opening of valve 71. Another path lS 15 145 adjacent the central portion thereof. Thus. from
the foregoing. it will be understood that a unitary pis
provided from chamber 105 to intermediate chamber 55
ton assembly 167 is provided, which includes ?rst piston
through passage 103, a magnetic valve 119 and conduit
117. Valves 109 and 113, respectively, includes screw
member 145 at the left end thereof, throttling member
needles 121 and 123 for varying the restrictions of the
131 in the middle thereof, and second piston member
inlet chamber 53 and outlet chamber 57 may be utilized
in the operation of control throttling valve 71 to obtain
valves.
When magnetic valves 115 and 119 are de-en
20 157 at the right end thereof, all as viewed in FIG. 2.
ergized, their needles 125, 127 close ?uid tight and there
is no path of escape for ?uid from chamber 105 to in
It will be noted in FIG. 2 that piston assembly 167
spans intermediate chamber 55 and outlet chamber 57.
Also, it will be noted that throttling member 131 and
second piston member 157 are so spaced that when the
termediate chamber 55. Thus, piston 83 and valve
member 73 are held ?rmly in the closed posTtion, both
by the bias of spring 101 and by the ?uid pressure ex 25 second piston member is seated, then discharge opening
129 is substantially closed by throttling member 131.
isting in inlet chamber 53, which is communicated to
chamber 105 through the path above described.
'
Head chamber 151 is in communication with interme
Second partition 51 is provided with cylindrical ds
diate chamber 55, preferably, through a conduit 168
charge port 129 therethrough adapted to permit the ?ow
provided in valve body 47 so that the pressure in head
chamber 151 is substantially the same as that in inter
of hydraulic ?uid from intermediate chamber 55 to out
let chamber 57. A cylindrical throttling member 131 is
mediate chamber 55. If desired, the head chamber 151
closely and sldably mounted in discharge port 129.
may be communicated with intermediate chamber 55
Throttling member 131 includes a substantially circular
through other means, as for example, a bore through
inner end wall 133 and an annular side wall 135 inte
stems 163 and 165, without departing from the spirit
grally formed with circular wall 133 adjacent the periph 35 and scope of the present invention.
ery thereof and slidably extending outwardly (to the
left as viewed in FIG. 2) through discharge port 129
into outlet chamber 57. The cylindrical side-wall 135 at
its outer end 137 is provided with spaced and substan
tially V-shaped notches 139 so that when the throttling 40
member 131 is moved to the right, as viewed in FIG.
An access opening 169 is provided in valve body 47
opposite bore 155 to provide means for installing and re
placing piston assembly 167. A cover plate 171 is pro
vided for opening 169 and is removably secured to valve
body 47 by means of bolts 173.
A compression spring 175 bears against ?rst piston
2, the notches provide gradually increasing passage area
member 145 so that piston assembly 167 is biased by the
to communicate intermediate chamber 55 with outlet
spring to the right as viewed in FIG. 2. A stop 176 is
chamber 57 and when the throttling member is moved
provided on the interior of cover plate 171 and extends
to the left as viewed in this ?gure, the notches provide
towards piston assembly 167 to limit movement thereof
gradually decreas ng passage area until the throttling 45 to the right. The outer end of ?rst piston member 145
is preferably cupped as at 177 to receive spring 175. The
member reaches its limit in its movement to the left,
which limit is shown in FIG. 2 and which substantially
opposite end of spring 175 is seated on shims 179, which,
in turn, are seated on cap 147.
closes off discharge port 129. Thus, the co-action of
throttling member 131 and discharge port 129 provides
From the foregoing, it will be understood that the op
a regulator or throttling valve 141, which is adapted to 50 posing forces acting on piston assembly 167 to control
the amount of opening or closing of throttling valve 141
throttle the ?uid ?ow from intermediate chamber 55 to
outlet chamber 57.
are as follows:
Valve body 47 is provided with a cylinder 143, which
(1) The opening forces tending to move piston assem
opens into outlet chamber 57 on the opposite side of
bly 167 to the right, as viewed in FIG. 2, to unseat sec
of cap 147, an annular cut-out portion 153 and the part
inlet chamber 53 exerted on second piston member 157
the outlet chamber from discharge port 129. Cylinder 55 ond piston member 157 and open throttling valve 141,
which opening forces include spring 175 and the force
143 is preferably, though not necessarily, of the same
of the ?uid pressure in head chamber 151 acting on the
diameter as discharge port 129 and is in spaced align
?rst piston member 145.
ment therewith. A ?rst piston member 145 is slidably
(2) The closing forces tending to move piston assem
mounted in cylinder 143.
bly 167 to the left, as viewed in FIG. 2, to seat second
A cap 147 is secured to valve body 47 as by bolts
piston member 157 and close throttling valve 141, which
149 and encloses the outer end of cylinder 143 to es
closing forces include the force of the ?uid pressure in
tablish a head chamber 151, which includes the interior
on an effective area thereof, which effective area is equal
of cylinder 143 exposed by piston member 145.
First part'tion 49 is provided with cylindrical bore 65 to the area of bore 155. As will be understood more fully
in the hereinafter described operation of valve assembly
155. For manufacturing considerations, bore 155 is pref
11, the pressure in the intermediate chamber 55 and thus,
in head chamber 151 is less than the pressure in inlet
discharge port 129 and cylinder 143, and in addition,
chamber 53, so that, in effect, the two opposing forces
is in alignment wIth discharge port 129 and cylinder 143
on the opposite side of the discharge port from the cyl 70 are provided by (1) spring 175 and (2) a net force which
equals the heretofore-mentioned force of the ?uid pres
inder. A second piston member 157 is closely and slid
sure in inlet chamber 53 exerted on second piston mem
ably ?tted in bore 155. Second piston member 157 is
her 157 minus the heretofore-mentioned force of the
provided at the end adjacent inlet chamber 53 with a
?uid pressure in head chamber 151 acting on the ?rst
beveled portion 159 to mate with corresponding beveled 75 piston member 145.
erably, though not necessarily, of the same diameter as
3,020,892
8
Piston assembly 167 will remain in the closed position
shown in FIG. 2 as long as controlled throttling valve 71
remains closed which is the condition that exists when
the elevator car 18 is at a stop. The aforementioned
fact that piston assembly 167 will remain in the closed
position is so for the following reasons:
There is no escape for ?uid from inlet chamber 53 be
cause valve 71 is closed and the full pressure in inlet
chamber 53 is exerted on second piston member 157.
When said full pressure is exerted on second piston 10
member 157, the heretofore mentioned net force acting
on piston assembly 167 is greater than the force of spring
175 and piston assembly 167 will remain in said closed
position. The spring tension of spring 175 should be so
valve 71 remains substantially constant, the volumetric
?ow through valve assembly 11. will remain substantially
constant and, therefore, cause a substantially constant
lowering speed of car 18 with any given opening of
valve 71.
When elevator car 18, in its lowering motion, ap
proaches a landing at which stopping is desired, electrical
circuits, not shown, are switched, as by switches, not
shown, located in the hoistway and engaged by elevator
car 18, to de-energize magnetic valve 115 and simultane
ously energize magnetic valve 119. Since the ori?ce of
passage 103 into cylinder 87 is, at this time, covered
by piston 83, there will be no escape for ?uid from cham
ber 105, so pressure therein rises nearly to equal that in
chosen that it exerts at all times a smaller force than 15 inlet chamber 53, and piston 83 with valve member 73
moves to the left, as viewed in FIG. 2, at a rate deter
said net force acting on piston assembly 167, due to an
mined by the setting of needle 121. As valve 71 closes
unloaded elevator car.
and restricts the ?ow through opening 69, the hereto
To lower elevator car 18, magnetic valve 115 is ener
gized by suitable switches and electrical circuits, not
fore-mentioned net force acting against spring 175 tends
shown. This will cause the pressure in chamber 105 to
be reduced since ?uid escapes from the chamber through
to rise, causing piston assembly 167 to move to the left,
as viewed in FIG. 2, restricting the ?uid ?ow through
conduit 117 into the lower pressure region in intermediate
discharge port 129.
When piston 83 travels far enough to the left to
uncover passage 103, egress is afforded for ?uid enter
ber 105 through conduit 111. It will be understood that
the ?uid pressure in intermediate chamber 55 is lower 25 ing chamber 105 through conduit 111, and closing mo
tion of valve member 73 is interrupted. The elevator
than that in inlet chamber 53, since there is some leakage
will now be descending at leveling speed, typically about
into outlet chamber 57 from intermediate chamber 55
one-fifth (Vs) of normal lowering speed. This leveling
past piston 145 and past throttling member 131. Needle
speed, for the same reasons heretofore-described for the
123 is adjusted to provide about twice the opening af
forded by needle 121. As a result, the pressure in inlet 30 faster lowering speed, will remain constant regardless of
load changes, since, with a heavier load, throttling valve
chember 53 acting to the right on piston 83, as viewed
141 will move toward closure to restrict the necessary
in FIG. 2, is greater than the sum of the pressures acting
?uid to maintain the pressure drop through valve 71
to the left on the opposite side of the piston. Piston
substantially constant.
83, therefore, moves to the right to open valve 71 and
chamber 55 at a greater rate than the ?uid enters cham
permit ?uid to discharge through opening 69.
This
causes the pressure in intermediate chamber 55, and
thus, the pressure in head chamber 151, to rise and the
pressure in inlet chamber 53 to drop until the heretofore
The next step in the operation after the levelling speed
is maintained, occurs when magnetic valve 119 is de-en
ergized, which causes the pressure in chamber 105 to
build up and the valve 71 to close which, in turn, causes
throttling valve 141 to close, and consequently, all ?ow
able to oppose the bias of spring 175, whereupon piston 40 of fluid through valve assembly 11 is stopped, which stops
mentioned net force exerted on piston assembly 167 is un
assembly 167 will move to the right, as viewed in H6. 2,
gradually moving notches 139 into intermediate cham
ber 55, thereby admitting corresponding ?uid ?ow to out
let chamber 57 from intermediate chamber 55. It should
the elevator car. As long as controlled valve 71 remains
closed, car 18 will remain completely stationary since
there is no escape of ?uid from inlet chamber 53, as here
tofore described, and consequently, there is no ?uid
be noted that the piston assembly 167 will actually begin
?ow through valve assembly 11.
To adjust the closing rate of the selectively controlled
its initial movement with the small ?ow through conduit 45
valve 71, the needle 121 is adjusted to the desired set
117, and then continue opening as above described.
ting. However, this causes the ?ow through valve 113,
When the heretofore-mentioned net force is such as
to balance the bias of spring 175, piston assembly 167
which is the adjustment for the opening rate of valve
will stop moving. As valve 71 opens wider and wider,
71, to vary inversely as the ?ow thorugh valve 109 is
increasing the ?ow from inlet chamber 53 to intermedi 50 changed, thereby necessitating a change in the setting
ate chamber 55, the heretofore mentioned net force on
of valve 113 every time valve 109 is changed. If it is
piston assembly 167 will tend to remain slightly less than
desired to eliminate this condition, the valve assembly 11
enough to balance spring 175 which will cause piston
is modi?ed so that the opening adjustment is provided
assembly 167 to follow the movements of valve 71 and
for valve 141 and eliminated on valve 71. Thus, re
open throttling valve 141 progressively wider. When 55 striction valve 113 is eliminated and an adjustable re
valve 71 reaches its limit of opening, which occurs when
striction valve 182 is provided in the conduit 168 between
piston 83 abuts screw 97, the tendency for said net force
intermediate chamber 55 and head chamber 151. This
to drop ceases and piston assembly 167 likewise ceases
modi?ed construction is shown in FIG. 3; and, as will be
apparent from this ?gure, valve 182 restricts the ?ow of
to move.
It will be understood that with a given opening of valve 60 ?uid when it ?ows in a direction from intermediate cham
71, as for example, the fully opened position above-de
ber 55 toward head chamber 151, thereby controlling the
scribed, the pressure drop through valve 71 will remain
rate of opening of throttling valve 141. In addition, in
substantially constant regardless of the pressure variation
passage 168, a ball check valve 183 is provided to permit
in inlet chamber 53. Thus, with a heavier load in ele
?uid to bypass valve 182 when the ?uid ?ows in a direc
vator car 18, which produces a greater pressure in inlet
tion from head chamber 151 towards intermediate cham
chamber 53, piston assembly 167 will move to the left
ber 55, thereby permitting free ?ow of ?uid during closing
as viewed in FIG. 2, to throttle down the ?uid ?ow and
of valve 141, and not affecting the closing thereof.
increase the pressure in intermediate chamber 55 so that
From the foregoing, it will be understood that the closing
the pressure drop through throttling valve 71 will remain
adjustment is independent of the opening adjustment and
constant; and with a lighter load, piston assembly 167 70
will move to the right, as viewed in this ?gure, to increase
the ?uid ?ow to drop the pressure in intermediate chamber
55 so that the pressure drop through valve 71 is like
wise regulated to a constant value. Since, with any given
one will not affect the other.
Referring now to the alternate embodiment of the valve
assembly which is shown in FIG. 4, only the lower part
of the modi?ed valve assembly is shown since the upper
opening of valve 71, the pressure drop through throttling 75 part thereof is identical with the upper part of the
8,020,892
preferred embodiment. The principal difference between
the two embodiments is in the relationship of the com
pression spring and the dire::tion of the ?ow of the ?uid ‘
through the discharge port.
The other differences be
tween the preferred and alternate embodiments will be
more apparent from the description to follow of the alter
nate embodiment. The modi?ed valve assembly of the
alternate embodiment includes a throttling valve 184 com
10
the thrust of compression spring 202. It is preferable to
have the ?uid flow in the opposite direction to the thrust
of the compression spring as in the preferred embodiment
for the following reasons:
Springs 175 and 202 will vary in force exerted as they
are compressed or allowed to expand. Thus, as springs
175 and 202 are compressed by piston assemblies 167 and
201 respectively, the forces exerted by the springs increase
prising a throttling member 185, similar in construction
somewhat; and ‘as the springs expand, the force exerted
to throttling member 131, cooperating with a discharge 10 by the springs decrease somewhat. This is an undesirable
port 187. However, as will be noted in FIG. 4, the spaced
condition, since it will cause somewhat of a variation in
notches 189 of throttling member 185 extend into inter
the pressure in intermediate chamber 55 in the two em
mediate chamber 55 rather than into the outlet chamber
bodiments for a given ?ow-rate through discharge ports
57 as in the preferred form.
129, 187. The impact of ?uid is greater when high pres
A cylinder 191 is provided in valve body 47 adjacent 15 sure ?uid passes through a small opening than when the
?rst partition 49. Cylinder 191 is spaced from discharge
same quantity of low pressure ?uid passes through a
port 187 and in alignment therewith. A ?rst piston mem
larger
opening. The ?uid ?ow through discharge open
ber 193 is slidably mounted in cylinder 191 and a second
ing
129
will strike portions of the piston assembly 167 in
piston member 195 is rigidly joined to ?rst piston mem
the path of the ?uid ?ow, as for example, the area 207 on
her 193 and slidably received in a bore 197. Second 20 the end of ?rst piston member 145, and the ?uid through
piston member 195 corresponds to second piston member
discharge port 187 will strike the area 209 on ?rst piston
157 in the preferred form, and it has the same function
member
193. In the preferred embodiment the effect of
and substantially the same structure with the exception
this ?uid impact will be in the proper direction to com
that second piston member 195 and bore 197 are smaller
in diameter than ?rst piston member 193 and throttling 25 pensate for the greater force exerted by spring 175 when
it is compressed more. Thus, when the opening of
member 185. A stem 199 rigidly interconnects throttling
member 185 and ?rst piston member 193 so that a unitary
piston assembly 201 is provided. A compression spring
throttling valve 141 is small as occurs with a high pressure
in intermediate chamber 55, the impact on area 207 will
be greater which will compensate for the greater force
exerted by spring 175, and when the opening of throttling
202 corresponding to compression spring 175 urges piston
assembly 201 towards opening of throttling valve 184,
30 valve 141 is greater, which occurs with a lower ?uid pres
It will be understood that the size of the second piston
sure in intermediate chamber 55, less force is exerted by
member 195 in ‘the alternate embodiment may be made
larger as in the preferred embodiment, or the second pis~
ton member 157 in the preferred embodiment may be
the ?uid on area 207, which is offset by the smaller force
exerted by the spring 175. In the alternate embodiment,
smaller as in the alternate embodiment, or the second
it will be apparent that this effect of the ?uid force on
termediate chamber 55 through a conduit 204.
stantially constant regardless of load variations whereby
closing time of the valve assembly and, therefore, distance
traveled during such time are, likewise, independent of
area 209 will not compensate for the differences in spring
piston members may be other sizes than those shown with
tension, but instead is additive.
out departing from the spirit and scope of the present in
From the foregoing description, it is apparent that the
vention, but it should be noted that the size of the
valve assembly 11 of the present invention and the alter
compression springs should be changed to compensate
nate embodiment thereof provide means for maintaining
for the changed area of the second piston member.
40 different lowering speeds constant at selected predeter
A chamber 203, which includes the space in cylinder
mined values which depend upon the opening of con
191 surrounding second piston member 195 and exposed
trolled valve 71, and which lowering speeds remain sub
by ?rst piston member 193, is in communication with in
From the foregoing, it will be understood that the op
posing forces acting on piston assembly 201 to control
the amount of opening or closing of throttling valve 184
load.
In addition, it is apparent that a compact valve
assembly is provided in which the components operate
smoothly without any adverse effects from turbulence.
(1) A ?rst force is provided by the pressure in inlet
Although the invention has been described and illus
chamber 53 acting on second piston member 195 tending 50
trated with respect to a preferred embodiment thereof, it
to close throttling valve 184.
is to be understood that it is not to be so limited since
(2) A second force provided by the pressure in inter
changes and modi?cations may be made therein which
mediate chamber 55 acting on throttling member 185
are within the full intended scope of this invention, as
tending to open throttling valve 184.
claimed.
(3) A third force tending to close throttling valve 184 55 hereinafter
We claim:
and provided by the pressure in chamber 203 acting on
1. In a hydraulic elevator control system having a jack
the net area 205 of ?rst piston member 193, which net
cylinder
and an elevator car supporting plunger recipro
area is equal to the cross-sectional area of ?rst piston
cable therein, means establishing a passageway including
member 193 minus the cross-sectional area of second pis
an opening therein, conduit means communicating said
ton member 195.
jack cylinder with said passageway whereby during descent
The combined effect of said ?rst force and said third
of said elevator car supporting plunger hydraulic ?uid is
force is greater than said second force whereby the net
adapted to ?ow from said jack cylinder through said pas
effect of the hydraulic ?uid on piston assembly 201 is a
sageway and through said opening, controlled valve means
net force equal to the combined ?rst and third forces
are as follows:
minus said second force which tends to carry piston as
sembly 201 towards closure of throttling valve 184. The
compression spring 202 opposes said net force to cause
operation of the valve assembly in a similar manner as
that heretofore described for the operation of the prin
cipal embodiment.
It will be apparent from a comparison of the preferred
and alternate embodiments that the ?uid ?ow through
throttling valve 141 is in the opposite direction to the
for selectively varying the effective size of said opening,
65 regulator valve means in said passageway downstream of
said opening for changing the ?uid back pressure on said
opening in accordance with changes in the ?uid pressure
upstream of said opening so that the pressure drop
through said opening is substantially constant for any given
70 effective size of said opening, whereby the volumetric
?uid ?ow through said opening and said passageway is
substantially constant to maintain the lowering speed of
said elevator car supporting plunger substantially constant
thrust of compression ‘spring 175, whereas the ?uid ?ow
for any selected size of said opening.
through throttling valve 184 is in the same direction as 75
2. The structure according to claim 1 including means
8,020,892
11
12
under pressure from said inlet chamber to said position
ing means and acting in opposition to said biasing means
for moving said throttling means towards closing of said
port to maintain the pressure drop through said opening
associated with said controlled valve means maintaining
substantially uniform acceleration and retardation of the
enlarging and closing of said opening from one effective
size to another regardless of the ?uid pressure upstream
of said opening whereby the acceleration and retardation
of said elevator car is maintained substantially uniform
regardless of load variations therein.
3. In a hydraulic elevator control system having a jack
cylinder and an elevator car supporting plunger recip
substantially constant and, therefore, the lowering speed
of said elevator car supporting plunger substantially
constant for any selected size of said opening.
6. The structure according to claim 5, in which said
positioning means includes an area thereon disposed in
the stream of hydraulic ?uid ?ow through said port and
arranged so that the increasing tension of said spring
rocable therein, means establishing a passageway includ
ing an opening therein and including a port therein, con
means acting on said positioning means as it is moved
duit means communicating said jack cylinder with said
in a direction causing closing of said port by said
throttling means is compensated for by the increasing
opposite force of the stream of hydraulic ?uid impinging
passageway whereby during descent of said elevator car
supporting plunger hydraulic ?uid is adapted to ?ow from
said jack cylinder through said passageway and through
said opening and said port, said port being located in said
passageway downstream of said opening, controlled valve
on said area disposed in the stream of hydraulic ?uid
?ow.
7. The structure according to claim 5 in which said
means for selectively varying the e?ective size of said
means for selectively varying the effective size of said
opening, throttling means in said port movable therein
to various positions for controlling the rate of ?ow 20 opening includes means maintaining substantially uniform
acceleration and retardation of the enlarging and closing
through said port, and positioning means connected to
of said opening from one e?ective size to another re
said throttling means and sensitive to ?uid pressure up
gardless of the ?uid pressure upstream of said opening
stream of said opening for changing the throttling e?ect
whereby the acceleration and retardation of said elevator
of said throttling means in accordance with changes in
car is maintained substantially uniform regardless of load
?uid pressure upstream of said opening so that the pres
25
sure drop through said opening is substantially constant
for any selected size of said opening regardless of changes
in ?uid pressure upstream of said opening, whereby the
volumetric ?uid ?ow through said opening and said pas
sageway is substantially constant to maintain the lower—
variations therein.
8. A valve assembly for maintaining a constant flow
of ?uid for any given setting of the valve comprising a
valve body, means in said valve body establishing a
passageway therethrough including an opening in said
passageway, means for delivering ?uid under pressure
ing speed of said elevator car supporting plunger substan
tially constant for any selected size of said opening.
to said passageway whereby ?uid is adapted to ?ow
through said passageway and through said opening, con‘
4. In a hydraulic elevator control system having a jack
trolled valve means for selectively varying the effective
cylinder and an elevator car supporting plunger recip
rocable therein, means establishing a passageway includ 35 size of said opening, said controlled valve means in ad
dition being operable to close off completely said open
ing an opening therein and including a port therein, con
ing to stop the ?ow therethrough, said controlled valve
duit means communicating said jack cylinder with said
including means for maintaining the retardation of ?ow
passageway whereby during descent of said elevator car
supporting plunger hydraulic ?uid is adapted to ?ow from
said jack cylinder through said passageway and through
said opening and said port, said port being located in said
passageway downstream of said opening, controlled valve
means for selectively varying the effective size of said
opening, throttling means in said port movable therein
through said opening during the closing thereof substan
40
tially constant regardless of pressure changes in said
passageway upstream of said opening, regulator valve
means in said passageway downstream of said opening
for changing the ?uid back pressure on said opening in
accordance with changes in the ?uid pressure upstream
of said opening so that the pressure drop through said
opening is substantially constant for any given effective
size of said opening, whereby the volumetric ?uid ?ow
through said opening and said passageway is substantially
constant for any given effective size of said opening.
to various positions for controlling the rate of ?ow
through said port, and positioning means connected to
said throttling means, said positioning means including
means for biasing said throttling means towards opening
of said port, and means communicating ?uid under pres
9. A valve comprising a valve body, means in said
sure from upstream of said opening to said positioning 50
valve body establishing a passageway therethrough in
means and acting in opposition to said biasing means for
cluding an opening therein and including a port therein,
moving said throttling means towards closing of said
means for delivering ?uid under pressure to said passage
port to maintain the pressure drop through said opening
way whereby ?uid is adapted to ?ow through said passage
and the volumetric ?ow through said passageway sub
stantially constant regardless of changes in the ?uid pres 55 way and through said opening and said port, means in
said opening to vary selectively the effective size of said
sure upstream of said opening.
opening
between various positions of opening down to
5. In a hydraulic elevator control system having a jack
a condition in which the ?ow is completely cut oil, means
cylinder and an elevator car supporting plunger recip
operably coupled to said means in said opening for main—
rocable therein, means providing an inlet chamber and
an intermediate chamber, conduit means communicating 60 taining the retardation of ?ow through said opening dur
ing the closing thereof substantially constant regardless
said jack cylinder with said inlet chamber whereby said
of pressure changes in said passageway upstream of
inlet chamber is adapted to receive hydraulic ?uid under
said opening, said port being located in said passageway
pressure from said jack cylinder, means providing an
downstream of said opening, throttling means in said
opening communicating said inlet chamber with said inter
mediate chamber whereby said opening is adapted to per 65 port movable therein to various positions for controlling
mit ?ow of ?uid from said inlet chamber into said inter
the rate of ?ow through said. port, and positioning means
connected to said throttling means and sensitive to ?uid
mediate chamber, means for selectively varying the effec
pressure upstream of said opening for changing the
tive size of said opening, means providing a discharge port
throttling effect of said throttling means in‘ accordance
for said intermediate chamber, throttling means in said
discharge port movable therein to various positions for 70 with changes in ?uid pressure upstream of said opening
so that the pressure drop through said opening is sub
controlling the discharge of ?uid from said intermediate
stantially constant, whereby the volumetric ?uid ?ow
chamber, and movable positioning means connected to
through said valve is substantially constant.
said throttling means, said positioning means including
10. A unitary valve for maintaining a constant ?ow
spring means for biasing said throttling means towards
opening of said port, and means communicating ?uid 75 of ?uid for any given‘ setting of the valve comprising a
13
3,020,892
hollow valve body, means in said valve body establish
ing an inlet chamber, an intermediate chamber, and an
outlet chamber; means for d: livering ?uid under pressure
to said inlet chamber, means forming an opening between
said inlet chamber and said intermediate chamber to
permit ?ow of ?uid from said inlet chamber to said
intermediate chamber, means associated with said open
ing to provide ?rst valve means for valving the flow of
?uid through said opening, control means for controlling
14
alignment; a unitary piston assembly including a throt
tling member intermediate the ends thereof, said unitary
piston assembly being slidably received in said bore and
said cylinder adjacent opposite ends thereof with said
throttling member being slidably received in said port,
said unitary piston assembly being movable as a whole
to carry said throttling member to various positions in
said port to control the ?uid flow from said intermediate
chamber into said outlet chamber, said unitary piston
the amount of opening of said ?rst valve means, said 10 assembly being provided with a seating portion adapted
?rst valve means being selectively controlled by said
to cooperate with said beveled seat to substantially close
control means between various positions of opening
off any ?uid leakage through said bore when said seating
down to a position in which the ?ow is completely cut
portion is seated thereagainst; said assembly having an
oil, means forming a discharge port between said inter
effective area adjacent one end thereof exposed to ?uid
mediate chamber and said outlet chamber to permit
under pressure in said inlet chamber to provide a ?rst
?ow of ?uid from said intermediate chamber to said
force tending to carry said assembly in one direction
outlet chamber, said valve body being provided with a
towards closure of said port by said throttling member
cylinder, means forming a bore between said inlet cham
and tending to carry said seating portion towards seat
ber and said intermediate chamber, means establishing
ing, said assembly having an opposing area on said throt
an additional chamber in communication with one end
tling member opposite said effective area and exposed to
of said cylinder, said cylinder being in communication
?uid under pressure in said intermediate chamber to pro
adjacent the opposite end from said additional chamber
vide a second force urging said assembly in a direction
with said outlet chamber; said port, said bore and said
to carry said throttling member towards opening, means
cylinder being spaced apart and being in axial alignment;
communicating ?uid pressure from said intermediate
a unitary piston assembly including a throttling member 25 chamber to a net area on said ?rst piston opposite said
intermediate the ends thereof, said unitary piston assem
opposing area to provide a third force tending to carry
bly being slidably received in said bore and said cylinder
said assembly in a direction towards closure of said port
adjacent opposite ends thereof with said throttling mem
by said throttling member, the combined effect of said
ber being slidably received in said port, said unitary
?rst force and said third force being greater than said
piston assembly being movable as a whole to carry said 30 second force whereby the net effect on said assembly is
throttling member to various positions in said port to
a net force equal to the combined ?rst and third forces
control the ?uid ?ow from said intermediate chamber
minus said second force which tends to carry said assem
into said outlet chamber, said assembly having an effec
bly towards closure of said port by said throttling mem
tive area adjacent one end thereof exposed to ?uid under
ber, compression spring means biasing said assembly in
pressure in said inlet chamber to provide a ?rst force 35 a direction opposite from said net force so that with any
tending to carry said assembly in one direction towards
closure of said port by said throttling member, means
communicating the ?uid pressure in said intermediate
chamber with said additional chamber and with portions
given setting of said ?rst valve means and with changes
in the ?uid pressure in said inlet chamber said assembly
is moved to maintain the pressure drop across said open
ing substantially constant, thereby maintaining the ?ow
of said piston assembly for establishing a net force act 40 of ?uid through said valve as a whole substantially con
ing on said piston assembly to urge said piston assembly
in a direction towards opening of said port by said
stant.
12. A unitary valve for maintaining a constant ?ow of
?uid for any given setting of the valve comprising a hol
said assembly in a direction opposite from said net force
low valve body, means in said valve body establishing an
so that with any given setting of said ?rst valve means
inlet chamber, an intermediate chamber, and an outlet
and with changes in the ?uid pressure in said inlet cham 45 chamber; means for delivering ?uid under pressure to
ber said assembly is moved to maintain the pressure drop
said inlet chamber, means forming an opening between
said inlet chamber and said intermediate chamber to per
across said opening substantially constant, thereby main
throttling member, compression spring means biasing
mit ?ow of ?uid from said inlet chamber to said inter
mediate chamber, means associated with said ?rst open
11. A unitary valve for maintaining a constant ?ow of 50 ing to provide ?rst valve means for valving the ?ow of
?uid through said first opening, control means for selec
?uid for any given setting of the valve comprising a ho1—
tively controlling the amount of opening of said ?rst
low valve body, means in said valve body establishing an
valve means, said ?rst valve means being selectively con
inlet chamber, an intermediate chamber, and an outlet
trolled by said control means between various positions
chamber; means for delivering ?uid under pressure to
said inlet chamber, means forming an opening between 55 of opening down to a position in which the ?ow is com
plctely cut off, means forming a discharge port between
said inlet chamber and said intermediate chamber to per
said intermediate chamber and said outlet chamber to
mit ?ow of ?uid from said inlet chamber to said inter
permit ?ow of ?uid from said intermediate chamber to
mediate chamber, means associated with said opening
said outlet chamber, said valve body being provided with
to provide ?rst valve means for valving the ?ow of ?uid
through said opening, control means for controlling the 60 a cylinder, means forming a bore between said inlet
chamber and said intermediate chamber and forming a
amount of opening of said ?rst valve means, said ?rst
beveled seat surrounding said bore on the side of said
valve means being selectively controlled by said control
partition adjacent said inlet chamber, means establishing
means between various positions of opening down to a
a head chamber in communication with one end of said
position in which the ?ow is completely out off, means
taining the ?ow of ?uid through said valve as a whole
substantially constant.
forming a discharge port between said intermediate cham 65 cylinder, said cylinder being in communication adjacent
the opposite end from said head chamber with said out
ber and said outlet chamber to permit ?ow of ?uid from
let chamber; said cylinder, said port and said bore being
said intermediate chamber to said outlet chamber, said
spaced apart and being in axial alignment; a unitary
valve body being provided with a cylinder, means form
piston assembly including a throttling member interme
ing a bore between said inlet chamber and said interme
70 diate the ends thereof, said unitary piston assembly being
diate chamber and forming a beveled seat surrounding
slidably received in said bore and said cylinder adjacent
said bore on the side of said partition adjacent said inlet
opposite ends thereof with said throttling member being
chamber, said cylinder being in communication adjacent
slidably received in said port, said unitary piston assem~
one end with said outlet chamber; said port, said bore
bly being movable as a whole to carry said throttling
and said cylinder being spaced apart and being in axial 75 member to various positions in said port to control the
3,020,892
?uid ?ow from said intermediate chamber into said out
let chamber, said unitary piston assembly being provided
with a seating portion adapted to cooperate with said
beveled seat to substantially close oil‘ any ?uid leakage
through said bore when said seating portion is seated
thereagainst; said assembly having an effective area adja
cent one end thereof exposed to ?uid under pressure in
said inlet chamber to provide a ?rst force tending to
carry said assembly in one direction towards closure of
16
supporting plunger is accelerated uniformly to a given
lowering speed regardless of changes in the ?uid pressure
upstream of said opening.
16. A unitary valve for maintaining a constant ?ow of
?uid for any given setting of the valve and for main
taining a uniform acceleration of the ?uid ?ow between
various settings of the valve comprising a hollow valve
body, means in said valve body establishing an inlet
chamber, an intermediate chamber, and an outlet cham
said port by said throttling member and tending to carry 10 ber; means for delivering ?uid under pressure to said
inlet chamber, means forming an opening between said
said seating portion towards seating, said assembly hav
inlet chamber and said intermediate chamber to permit
ing an opposing area on said ?rst piston opposite said
?ow of ?uid from said inlet chamber to said intermediate
effective area and exposed to ?uid under pressure in said
chamber, means associated with said opening to pro‘
head chamber, means communicating said intermediate
chamber with said head chamber whereby the ?uid pres 15 vide ?rst valve means for valving the ?ow of ?uid
through said opening, control means associated with said
sure in said intermediate chamber is communicated to
?rst valve means for controlling the amount of opening
said opposing area to provide a second force tending to
of said ?rst valve means, said ?rst valve means being
carry said assembly in the opposite direction towards
selectively controlled by said control means between vari
opening of said discharge port by said throttling member,
ous positions of opening down to a position in which
said ?rst force being greater than said second force
the ?ow is completely cut off, said control means in
whereby the net e?ect on said assembly is a net force
cluding means operable responsive to the differences be
equal to said ?rst force minus said second force which
tween ?uid pressures in said inlet chamber and said in
tends to carry said assembly towards closure of said dis
termediate chamber, means forming an opening between
charge port by said throttling member, compression spring
means biasing said assembly in a direction opposite from 25 said inlet chamber and said intermediate chamber to
permit ?ow of ?uid from said intermediate chamber to
said net force so that with any given setting of said ?rst
said outlet chamber, said valve body being provided
valve means and with changes in the ?uid pressure in
with a cylinder, means forming a bore between said inlet
said inlet chamber said assembly is moved to maintain
chamber and said intermediate chamber, means establish
the pressure drop across said opening substantially con
stant, thereby maintaining the ?ow of ?uid through said 30 ing an additional chamber in communication with one
end of said cylinder, said cylinder being in communi
cation adjacent the opposite end from said additional
chamber with said outlet chamber; said port, said bore
able restriction valve means in said means communicat
and said cylinder being spaced apart and being in axial
ing said intermediate chamber with said head chamber
for adjusting the ?uid ?ow from said intermediate cham 35 alignment; a unitary piston assembly including a throt
tling member intermediate the ends thereof, said unitary
ber towards said head chamber to adjust the opening rate
piston assembly being slidably received in said bore and
of said throttling member.
said cylinder adjacent opposite ends thereof with said
14. The structure according to claim 12 in which said
throttling member being slidably received in said port,
piston assembly includes an area thereon disposed in the
valve as a whole substantially constant.
13. The valve according to claim 12 including a vari
stream of hydraulic ?uid ?ow through said port into said
outlet chamber and arranged so that the increasing ten
sion of said spring means acting on said piston assembly
as it is moved in a direction towards closure of said port
said unitary piston assembly being movable as a whole
to carry said throttling member to various positions in
said port to control the ?uid ?ow from said intermediate
chamber through said notches into said outlet chamber,
is compensated for by the increasing opposite force of
said assembly having an e?ective area adjacent one end
thereof exposed to ?uid under pressure in said inlet
chamber to provide a ?rst force tending to carry said
assembly in one direction towards closure of said port
the stream of hydraulic ?uid impinging on said area dis
posed in the stream of hydraulic ?uid ?ow.
15. In a hydraulic elevator control system having a
jack cylinder and an elevator car supporting plunger
by said throttling member, means communicating the
reciprocable therein, means establishing a passageway in
?uid pressure in said intermediate chamber with said
cluding an opening therein and including a port therein,
additional chamber and with portions of said piston as
50
conduit means communicating said jack cylinder with
sembly for establishing a net force acting on said piston
said passageway whereby during descent of said elevator
assembly to urge said piston assembly in a direction
car supporting plunger hydraulic ?uid is adapted to ?ow
towards opening of said port by said throttling member,
from said jack cylinder through said passageway and
compression spring means biasing said assembly in a di
through said opening and said port, said port being lo
rection opposite from said net force so that when said
cated in said passageway downstream of said opening, 55 valve means is changed from one position to another
normally closed valve means in said opening for stop
said assembly is moved to cause the di?erences between
ping the ?ow therethrough to hold the elevator car at a
pressures in said inlet chamber and said intermediate
stationary position, said valve means being movable in
chamber to follow substantially the same pattern regard
said opening to at least one open position of a given size
less of changes in ?uid pressure in said inlet chamber,
to lower said elevator car supporting plunger, control 60 whereby there is uniform acceleration and retardation of
means connected to said valve means for the opening
the ?uid ?ow regardless of changes in pressure in said
thereof and operable responsive to the differences between
inlet chamber.
?uid pressures upstream and downstream of said open—
17. A valve assembly comprising a body, means in said
ing, throttling means in said port movable therein to
body establishing a passageway therethrough including
65
various positions for controlling the rate of flow through
an opening therein and a port therein, means for deliver
said port, and positioning means connected to said throt
ing ?uid under pressure to said passageway whereby ?uid
tling means and sensitive to ?uid pressure upstream of
is adapted to ?ow through said passageway and through
said opening for changing the throttling e?ect of said
said opening and said port, valve means associated with
throttling means in accordance with changes in ?uid pres
said opening, control means associated with said valve
sure upstream of said opening so that when said valve 70 means for closing said opening from at least one e?ec—
means is opened from said normally closed position to
said open position the differences between pressures up
stream and downstream of said opening follow substan
tially the same pattern regardless of changes in ?uid
tive opening size to a completely closed position, said
control means including means establishing a cylinder
in said body, a piston slidably mounted in said cylinder,
pressure upstream of said opening, whereby said elevator 75 said piston and said cylinder establishing a chamber, a
17
3,020,892
?rst conduit providing communication between said pas
sageway downstream of said opening and said chamber,
means for selectively opening and closing said ?rst con~
duit, said cylinder opening into said passsageway up
stream of said opening on the opposite end of said pis
ton from said chamber whereby the position of said pis
ton is responsive to the differences in ?uid pressure be
tween said chamber and said passageway upstream of
said opening, biasing means urging said piston towards
18
opening, conduit means providing communication be
tween said passageway upstream of said opening and said
chamber, said conduit means being effective when said
?rst conduit is closed to raise the pressure in said cham
her by said given amount to the pressure in said pas
sageway upstream of said opening, when the pressure
is the same in said chamber as in said passageway up
stream of said opening said biasing means being effective
to cause closure of said opening, the retardation of said
closure of said opening, when said ?rst conduit is open 10 ?ow through said opening during the closing thereof
and the ?uid pressure in said chamber is substantially
being determined by the rate of How through said con
the same as the ?uid pressure in said passageway down
duit means during raising of the pressure in said cham
stream of said opening said piston being disposed in a
her by said given amount, whereby said retardation re
position to cause said valve means to establish one ef
mains substantially uniform regardless of pressure
fective size of said opening, throttling means in said 15 changes in said passageway upstream of said opening.
port movable therein to various positions for controlling
the rate of ?ow through said port, positioning means con
References Cited in the ?le of this patent
nected to said throttling means and sensitive to ?uid
pressure upstream of said opening for changing the
UNITED STATES PATENTS
throttling effect of said throttling valve in accordance 20 1,725,374
with changes in ?uid pressure in said passageway up
1,904,475
stream of said opening so that the di?’erence between
2,560,948
the ?uid pressures in said passageway upstream and
2,782,598
downstream of said opening is substantially constant at
2,785,660
a given amount for any one given e?‘ective size of said 25
2,925,066
Rush ________________ __ Aug. 20, 1929
Kissing ______________ .. Apr. 18, 1933
Hannibal et al _________ __ July 17, 1951
Gatwood _____________ __ Feb. 26, 1957
Jaseph ______________ __ Mar. 19, 1957
Thorner _____________ __ Feb. 16, 1960
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