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Патент USA US3052107

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Sgpt. 4, 1962
.1. M1 TYRNER
3,052,097
ELECTED-DYNAMIC ACTUATOR
Filed Dec. 31. 1959
2 Sheets-Sheet 1
I6
12 ‘
l9
INVENTOR.
\iwéw \w/\-Q-\
BY W‘
M QM
ATTORNEYS
Sept. 4, 1962
3,052,097
J. M; TYRNER"
ELECTRO-DYNAMIC ACTUATOR
2 Sheets-Sheet 2
Filed Dec. 31. 1959
116
INVENTOR.
\% m. 4M
BY
W\m
AT TOA§NEY$
3,052,997
United States Patent 0 ”
Patented Sept. 4, 1962
2
I
the diaphragm may be used to operate or actuate a con
3,il52,097
ELECTRQ-DYNAMTC ACTUATQR
Joseph M. Tyrner, MR. 17, Morristown, NJ.
Filed Dec. 31, 1959, Ser. No. 863,261
9 Claims. (Cl. 66-52)
nected device.
Change of the current in coils 4 changes the pressure
in the plenum chamber, because the rotational speed of
the mercury depends on the strength of the rotary mag
netic ?eld. Response is fast since only the mass of a
thin walled mercury cylinder has to be accelerated or
This invention relates to actuators for producing move
retarded.
ment of parts in response to energizing of the actuator
The mercury which is moved from the gap 3 into the
by an electric current.
The ever increasing use of electronic controls and data 10 chamber 7 is replaced from a center pool 9 through con
necting channels 10 and 11. In the center of this pool
reducing equipment calls for simple electric actuators,
is a resistor 12, which is partially short circuited by the
which should be more suitable to cooperate with electric
mercury. The amount of resistance reduction depends
apparatus than the presently employed pneumatic devices.
on the mercury level and consequently on the amount
It is an object of this invention to provide an improved
transferred to the plenum chamber. Therefore the re
electric actuator which delivers a working ?uid under
sistor may ‘be used to provide a feedback signal on the
pressure against a diaphragm or to a ?uid motor cham
mechanical motion of the diaphragm. The ratio of dia
ber connected with the part to be moved. The invention
phragm area to the pool cross section provides ampli?ca
is suitable, therefore, for direct mechanical connections
tion of the actual mechanical displacement.
or for use in apparatus designed for ‘operation by ?uid
structurally the two cores 1 and 2 ‘are supported and
under pressure.
spaced by end covers 13 and 14. A center tube 15 ties
The invention utilizes, as a working ?uid, a liquid
the two covers together. Inside of the center tube is
which is ‘a good conductor ‘of electricity. The preferred
the
pool 9, which may be inspected and replenished by
?uid is mercury. This liquid is placed in a chamber
removing a cap 16. The diaphragm 8 is fastened to
having electric coils which generate a rotating magnetic
the outer core 2 by means of two rings 17 and 18. Cool
?eld which induces currents in the liquid. The ooaction
ing ?ns 19 on the core 2 improve the ‘dissipation of heat
of the ?eld and induced currents causes rotation of the
developed in the coils ‘and in the rotating mercury.
liquid and this movement of the liquid produces a cen
A yoke 21 is secured to the center of the diaphragm 8
trifugal force. It is this centrifugal force that causes
a rise in the ?uid pressure; and the extent of the pressure
rise is controlled by changing the strength of the magnetic
?eld to make corresponding changes in the centrifugal
force.
The principle of utilizing coiacting ?elds and currents
has been used to obtain a centrifugal pumping operation
for electrically conductive liquids, such as alloys of so
dium and potassium; but is not believed to have been
used before this invention for developing pressure in an
actuator.
Other objects, features ‘and advantages of the inven
tion will appear or be pointed out as the description
proceeds.
In the drawing, forming a part hereof, in which like
reference characters indicate corresponding parts in all
the views;
by a screw 22 or other fastening means; and motion of
the diaphragm 8 is transmitted, to a part to be actuated,
through a link 32.
Variations in the mechanical con?guration are feasible.
For instance the exciting coils 4 can be placed on the
outer core.
However this results in a winding which is
harder to manufacture without offering any advantage
in performance.
Another variation of the device is a design with a mer
cury disc instead of a mercury cylinder. This con?gura
tion is shown in FIGURE 3. Since the rotating mercury
disc is not ‘as well cooled as the mercury cylinder in the
preferred design, a circulating ?ow is provided, which
replaces continuously the heated up content of the disc.
FIGURE 3 shows a modi?ed form of the actuator in
which a housing 40 has its lower end closed by a dia
FIGURE 1 is a vertical sectional view through an ac 45 phragm 42 held in place by a rim 44. It will be under
stood that the diaphragm 42 may be similar to the dia
tuator made in accordance with this invention;
phragm 8 shown in FIGURE 1 and it may be attached
FIGURE 2 is a sectional view, on a reduced scale,
to the housing in the same way and provided with motion
taken on the line 2-—-2 of FIGURE 1;
transmitting
mechanism such as already described in
FIGURE 3 is a sectional view, corresponding to FIG
URE 1, but showing a modi?ed form of the invention; 50 FIGURE 1.
Within the housing 40 there is an upper core 46 at
FIGURE 4 is ‘a sectional View, ‘on a reduced scale,
tached
to the top of the housing and a lower core 48
taken ‘on the line 4—4 of FIGURE 3;
supported by a ?ange 50 which extends from a center
FIGURE 5 is a block diagram for the actuator shown
post 52. The center post is hollow and has a passage 54
in FIGURE 1, with manual control and remote position
55 opening through its bottom end and extending upwardly
indication; and
to cross passages 56 which open into a supply chamber
FIGURE 6 is a block diagram for the actuator with
58 located above the top of the housing 40.
feedback control tied into a larger system.
Above the cross passages 56, the interior of the post
The preferred embodiment of the invention is shown
52 is threaded and there is a needle valve 60 screwed
in FIGURE 1. The main parts are two concentric cores
into these threads and extending downwardly to the cross
1 and 2, with a mercury ?lled gap 3 between them. The
passages 56. When the needle valve 60 is screwed down
as far as it will go, the lower pointed end of this valve
electric conductivity. Coils 4 are provided, which, when
closes the passage 54 so that no liquid can ?ow into the
energized, excite a rotary ?eld. Since this ?eld traverses
cross passages 56. As the needle valve 69 is backed
the mercury cylinder radially, it induces current in it. 65 off by screwing in a direction to raise it, the communi
The coaction of the current with the ?eld causes the
cation between the vertical passage 54 and the cross
mercury cylinder to rotate. This effect is similar to the
passage 56 becomes progressively larger.
rotation of a squirrel cage rotor in the ?eld of an in
A cap 62 screws over the upper end of the post 52
duction motor. Centrifugal forces, set up by the rota
above the top of the supply chamber 58. This cap con
tion, drive the mercury through channels 5 and 6 into 70 tacts with the top of the supply chamber when screwed
down to its full extent. The cap 62 is removed when
a plenum chamber 7. The pressure, which is built up
ever it is necessary to adjust the needle valve 60.
in the plenum chamber deforms a diaphragm 8. Thus
mercury in the gap forms a thin walled cylinder with good
3,052,097
3
4
graduated to show displacement of the diaphragm of the
There are windings 66 on the upper and lower cores
46 and 48, respectively. These windings, when ener
gized, set up a rotary electric ?eld in the space between
the confronting faces of cores 46 and 48. When the
housing 40 is ?lled with conductive liquid, preferably
actuator.
As the level of the liquid 9 rises, a larger portion of
the resistor 12 is short circuited by the liquid and the
?ow of current through the signal device 82 is increased.
mercury, the portion of the liquid between the confront
ing faces of the cores 46 and 48 ‘forms a disc and this
Conversely, as the level of the liquid 9 drops lower with
greater displacement of the diaphragm of the actuator,
disc is caused to rotate around the axis of the post 52
a smaller portion of the resistor 12 is short circuited
as a result of the co-action of the magnetic ?elds set up
and the amount of current ?owing through the signal
around the cores 46 and 48 by the current in the wind 10 device 82 decreases. It will be understood that this
ings 66 and by the induced current in the liquid be
change in current is a function of the displacement of
tween the faces of the cores 46 and 48.
the diaphragm and a measure of the motion of the
This rotation of the liquid disc between the cores 46
actuator.
and 48 produces centrifugal force which acts on the
A feedback control system is shown in the block dia
liquid and causes it to flow radially outward from be 15 gram FIGURE 6. Coils 4 and resistor 12 are con
tween the faces of the cores 46 and 48. This move
nected to an ampli?er 90, which also is connected to
ment of the liquid under centrifugal force is indicated
the powerline 84 and the command station 92. The
by arrows in FIGURE 3; and the liquid which moves
latter provides a command voltage which the ampli
outwardly against the sides of the housing 40 is forced
?er compares with the feedback signal from resistor 12.
downwardly and exerts pressure against the diaphragm
If a difference exists the ampli?er changes the excitation
‘42 causing displacement of the diaphragm in the same
of coils 4 accordingly, and‘ in the proper course of ac
‘manner as described in connection with FIGURE 1.
tion the displacement of the mercury 9 around resistor
Some of the liquid ?ows upwardly through the vertical
12 is changed until the feedback signal voltage equals
passage 54 in the center post 52 and flows through the
the command voltage. Thus to every command signal a
cross passage 56 into the supply chamber 58. The 25 diaphragm position is coordinated, regardless of the
amount of liquid which can thus escape from the hous
forces which the diaphragm encounters in this position.
ing 40 will depend upon the setting of the needle valve
60.
If the needle valve is closed, no liquid can pass
upwardly through the passage 56, but as the needle
'valve is set in progressively wider open positions, more
liquid can move upwardly through the passage 54 and
this limits the pressure on the diaphragm for any given
excitation of the cores 46 and 48.
There are other vertical passages 70 leading from the
liquid supply chamber 58 downwardly through a parti
The ampli?er and command stations are devices as em
ployed in conventional servo mechanisms.
The preferred embodiment and one modi?cation of
the invention have been illustrated and described, but
other changes and modi?cations can be made and some
features can be used in different combinations without
departing from the invention as de?ned in the claims.
What is claimed is:
35
1. An actuator including a chamber for containing an
tion of the actuator and opening into a space within the
center portion of the actuator at the inner side of the
liquid disc which is formed by the portion of the liquid
located ‘between the confronting faces of the cores 46
electrically conductive liquid, coils adjacent to the cham
ber and in position to set up a rotary electro-magnetic
?eld that traverses the liquid in the chamber and that pro
duces currents in the liquid so that coaction of the rotary
and 48. As liquid is forced outwardly by centrifugal 4-0 ?eld with a ?eld of the induced currents causes rotary
force, new liquid from the supply chamber 58 ?ows
movement of the liquid, the actuator having space therein
downwardly through the passages 70 to replace the liquid
which has moved outwardly.
?lled with liquid that is a continuation of the mass of
liquid moved by the rotary ?eld and in position to be acted
The pressure output of the actuator depends on the
upon by the centrifugal force developed by the moving
speed of rotation of the mercury cylinder (or disc).
liquid, and in which the chamber is shaped so that the
principal part of the liquid that is subjected to the in
This speed, and with it the pressure output, may be con
trolled by varying the intensity of the rotary ?eld which
'induces the rotation. The control does not affect the
speed of the ?eld which stays constant, but the inevitable
friction between the moving mercury and its stationary 50
duced currents is a mass of liquid having substantially
the shape of a hollow cylinder with an inside diameter
much greater than the radial thickness of the mass of
liquid forming said hollow cylinder.
boundaries slows down the ?uid cylinder (or disc) and
2. An actuator including a chamber for containing an
slows it down more if the motion inducing force is
weak.
electrically conductive liquid, coils adjacent to the cham
ber and in position to set up a rotary electro-magnetic
?eld that traverses the liquid in the chamber and that
55 produces currents in the liquid so that coaction of the ro
phase ?eld is preferred which requires ampli?cation of
tary ?eld with a ?eld of the induced currents causes rotary
the command signal into a two-phase excitation. A sim
movement of the liquid, the actuator having space therein
pler method of control is the use of two counter ro
?lled with liquid that is a continuation of the mass of liq
tating ?elds which exert torques in opposite directions.
uid moved by the rotary ?eld and in position to be acted
The resulting torque acting on the mercury, then is the
upon by the centrifugal force developed by the moving
difference of the two torques. If one of the ?elds is
liquid, and in which the actuator has a supply pool in
of constant intensity, control of the other results in a
communication with the chamber from which make-up
Control of a rotary ?eld requires control of the ex
citation of all phases. For economical reasons a two
controlled acting torque. It can be shown that this kind
of control can be achieved by using a two-phase wind
ing with one phase on a constant and the other on con
trolled excitation. Therefore one phase is connected
directly to the line and only the other one to the ampli
?er, which now converts the command signal into a
liquid flows to replace that which is moved outwardly
by centrifugal force, and in which the pool is at a level
from which the liquid can ?ow by gravity to the chamber
and there are automatic means in the pool responsive to
the depth of liquid in the pool for controlling a circuit of
single phase excitation.
the actuator.
3. An actuator including a chamber for containing an
FIGURE 5 shows a wiring diagram for the actuator
shown in FIGURE 1. The actuator is manually con
trolled from a station 80. The resistor 12 shown dia
and in position to set up a rotary electromagnetic ?eld
grammatically in FIGURE 5, is in series with a signal
device 82 connected with a power line 84. This signal
electrically conductive liquid, coils adjacent to the chamber
that traverses the liquid in the chamber and that produces
currents in the liquid so that coaction of the rotary ?eld
with a ?eld of the induced currents causes rotary move
device may be constructed as an ammeter with a scale 75 ment of the liquid, the actuator having space therein ?lled
3,052,097
5
6
8. The actuator described in claim 7 and in which the
movable wall is a diaphragm closing a second chamber
of the actuator, and the second chamber extends all the
way across the end of the actuator beyond ends of the
cylindrical faces of the cores,
there are passages open
with liquid that is a continuation of the mass of liquid
moved by the rotary ?eld and in position to be acted
upon by the centrifugal force developed by the moving
liquid, and in which the actuator includes space in which
the level of the liquid varies with the displacement of
liquid by the centrifugal force, and the actuator has means
responsh e to changes in the liquid level for controlling
ing throuhg the inner face of the outer core and through
which the chamber between the cylindrical faces of the
cores communicates with said second chamber.
9. An actuator comprising a housing enclosing a cham
4. The actuator described in claim 5 and in which there
her for holding electrically conductive liquid, a movable
is space in the actuator from which liquid is withdrawn by
wall of the housing which is displaced by pressure in the
the action of the centrifugal force, and the means respon
housing, two cores within the chamber and having con
sive to changes in the liquid level are in the space from
fronting faces spaced from one another to provide a disc
which the liquid is withdrawn.
shaped space between said faces, windings on the cores
5. The actuator described in claim 4 and in which the
means responsive to the changes in the liquid level include 15 for producing, when electrically energized, a rotary ?eld
a resistance coil that extends into the liquid and that is
in the space between the confronting cores, a liquid supply
short circuited by the liquid to the extent that the coil is
chamber separated from the chamber which contains the
submerged.
cores by a partition, a passage leading from the portion
6. An actuator including an inner core having a cylin
of the core chamber in position to receive liquid which
drical outer lace, an outer core having an inner cylindrical
has been displaced from between the core faces by cen
face confronting the outer face of the inner core and form
trifugal force, another passage through which liquid from
ing therewith a cylindrical chamber, windings on one of
the supply chamber ?ows into the core chamber at a loca
the cores in position to set up, when electrically energized,
tion inward from the disc-shaped space between the con
a magnetic ?ux about an axis transverse of the axis of the
fronting taces of the cores, and a needle valve for con
cylindrical face of the core having the windings thereon,
trolling the rate of flow of liquid between the core cham
a movable wall of the actuator closing a space of the ac
her and the supply chamber.
tuator that communicates directly with the chamber be
tween the cores and at a location toward which the liquid
References @ited in the ?le of this patent
is displaced by centrifugal force when liquid is caused to
a circuit of the actuator.
rotate by a rotary ?eld produced by electrical energization 3O
of the windings.
7. The actuator described in claim 6 and in which the
movable wall is connected with motion transmitting means
for operating an element that is to be moved by the ac—
tuator.
35
UNITED STATES PATENTS
2,658,452
2,730,951
2,934,960
2,948,1‘l8
Donelian _____________ __ Nov. 10,
Donelian et a1. _______ __ Jan. 17,
Robinson ____________ __ May 3,
Carlson et a1. _________ __ Aug. 9,
1953
1956
1960
1960
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