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Патент USA US2406356

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'Aug- 27,1946‘ `
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J. s. w. DAvlDsENv
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. »2,406,356
ROTARY ELECTRICAL BOOST DEVICE FOR REDUCING l
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CONTROL
FORCES
ON
AIRPLANES
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Filed 'June 16, 1942
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2,405,356
Patented Aug. 27,_ 1946
‘UNITED STATES PATENTpOFFICE
2,406,356
ROTARY ELECTRICAL BOOST DEVICE FOR
REDUCING CONTROL FORCES _ON AIR
PLANES
>Jess S. W. Davidsen, Mountain View, Calif.
Application June is, 1942, serial No. 447,270
3 Claims. (Cl. 244-83)
(Granted under the act of March 3, 1883, as
amended April 30, 1928; 370 O. G. 757)
1
This invention relates to control systems for
2
impose aA snubbing'action against suddenly ap
aircraft and more particularly to a booster con
plied external loads such as those -' which fre
trol system for aircraft similar to the booster con
trol system described and claimed in my copend
quently result from kgusts or rough air; and to '
perform the snubbing action Without loss of “feel” Y
ing application, Serial No. 417,433, filed November
or pilot reaction.
1, 1941.
It is recognized by those skilled in the art re
lating to aircraft controls to whom this specifi
cation is particularly addressed that hydrauli
cally actuated control devices have certain in
tage over the strictly hydraulic type in that the
electric energy can be delivered to the motor
herent objections when used atextremely high
altitudes. Thisl is due to the fact that the low
temperatures there encountered cause the fluid
viscosity to increase to such an extent that the
hydraulically actuated boost devices either be
come inoperative, `or extremely sluggish _in their
operatic-n. The regions of today’s military opera
.
,
,
From the standpoint of military vulnerability,
the electric powered boostdevice has an advan
through `a plurality of parallel power leads, thus
a number of the leads maybe severed without
,affecting the operation of the device,` whereas
the strictly hydraulictype is rendered inoperative
once its supply line is punctured; It is also recog
nized that a further simplification from ,the
standpoint of military vulnerability or other con'
siderationsvcan be affected by the substitution of
an air turbine in place of an electric motor to
tions require booster devices which will be unef
furnish energy for the rotary boost device. The
fected by the low temperature encountered at
these extreme altitudes. The prior artshows that 20 pressure head required to operate the turbine
would, o-f course, be the impact pressure created
the limitations on these hydraulically actuated
by the movement ofthe aircraft relative to its
devices lhave been acknowledged. The general
flight sustaining medium, and the initial source
solution of the `particular problem involved has
of energy would be the motoror motors' pro
been an attempt to design a hydraulically
pelling the craft. Energy is actually stored in
actuated device ' which may be “shut off” or
the rotating system by reason of its inertia and
rendered inoperative, and one which, when made
the fact that the imposed boost loads are of an
inoperative, offers- no additional loads to the pilot.
intermittent nature.
.
1
.
Thus the low temperatures and high viscosity en
It is a further object of this invention,_therecountered at high altitudes have necessitated
shutting off the boost system. My copending ap- ~
plication to which reference has been made above
is concerned with such a proposition. Notwith
standing the fact that I believethe subject mat
ter of my copending application to be a satis
factory solution in this regard, it is my purpose
here to present a control device which will be
unaffected by low temperatures, thereby `avoiding
the present necessity of shutting off the booster
system at these low temperatures thereby also
avoiding the present necessity of requiring'the
fore, to provide a booster control system for air
craft which utilizes the kineticenergy of a rotat
ing inertia member to apply a variable and in
termittent booster force to aid in positioning the
control surface of an aircraft.
Other objects and advantages will become ap
parent from the specification as the specific fea
tures of certain preferred modiñcations of this
inventionv are hereinafter described in detail in
connection with the accompanying drawing, in
which
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Fig. l is a schematic view of the control mech
pilot to handle the full control surface loads. To
anism of this invention;
accomplish this purpose I propose to provide a
Fig. 2 is an elevational view in cross-section of
servo-booster device which in its preferred form
the rotary power transmitting system, and fric
utilizes electrical energy vto supply the necessary
45 tion means for transmitting the torque thereof
assisting force.
on to said control surface;
It is an object of this invention to provide a
Fig, 3 is a cross-sectional plan view taken on
novel booster control system for aircraft, the op
line 3-3 of Fig. 2;
eration of which is unaffected by low tempera
Fig. 4 is a cross-sectional plan view taken on
tures, and as in the system described in my co
pending application offers no additional loads to 50 line 4-4 of Fig. 2;
Fig. 5 is a schematic view of a modification il
the pilot when shut off or rendered inoperative;
lustrating a push-pull system of control; and
and which exerts an assisting force proportional
Fig. 6 is a partial schematic view of a modifica
to the pilot’s manual effort.
tion wherein an air turbine is utilized to provide
It is also an object to provide a booster con
a rotary torque to said «power transmitting sys
trol system Which will assure that the changes in
tem.
control reaction will be felt‘by the pilot to a high
Referring now to the drawing and particularly
degree of fidelity.
to Fig. l wherein I have illustratedl a preferred
It is a further object of this invention to pro
embodiment of this invention in which reference
vide a control device which when not in use, or
when rendered inoperative, will still function to 60 numeral lll designates a control surface of an air
2,406,356
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craft. This control surface I0 which may be
either an aileron, elevator or rudder is pivoted to
its supporting structure "I I and positioned about
this pivot by means of a force transmitting sys
tem which includes the cables I2 and I3. One
key slot formed in each of the supporting mem
bers has an arcuate extension 2ϡ. This key slot
permits relative movement of each supporting
member and its torque transmitting member
through an angle of 2a”. The lugs 62 and `t3 are
end of each of these cables -is secured to the con- ` " provided on> each of the supporting members and
ytrol horn I4 at its opposite» ends and lis con«
a tension spring 54 _is secured to each lug so as to
nected intermediate its ends to the opposite ends
keep the two supporting membersV 45 and 41 in
of the protruding arms 8 and‘9 respectively of ' ‘_.the'position illustrated in the drawing wherein
the pivoted force transmitting member -i5.~ The v10h the key -59 engagesppposite ends of the key slots l
otherend of each of the cables I2 and _I3 is_s_e_- _ _ '
curely fastened to its respective pistonÜIB and
I9 of the fluid coupling membersindicated gen
The- operation of the device, as schematically
illustrated in Fig. l, is as follows:
'
-
erally on the drawing at I6 and I1; Each of these '
As illustrated in Fig. l, motor 60 is presumed to
iluid couplings includes a fluid-tight cylindrical 15 be rotating in the direction indicated by the ar
chamber 28 and V2I enclosing its respective piston
row B to provide for -rotation of the drum 52 in
a clockwise direction when viewed from above
and to provide for rotation of the drum 53 in’an
oted control column 1 is connected by means of `
opposite or counter-clockwise direction as viewed
Vthe cables 22 and 23 Vto the cylinders 28 and 2| of 20 from above by means of beveled gears 5S, 51 and
I8 and'v I9 so as to provide a fluid-tight space for
a low yviscous liquid such as kerosene. The piv
the -ñuid couplings. The cable is secured toop
posite ends of the pivoted spreader bar 24 inter
58, When the operator moves the control column
or stick 1 of Fig. 1 in the direction shown by arrow
mediate its ends so as to permit any initial rig
A, tensionV is supplied to the cables 22 and I2.A
ging tension to be applied at the cable without
This tension creates a pressure on the fluidV in
affecting the ñuid pressure within the couplings 25 the fluid coupling I (i, which is transmitted by the
IB’and
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, flexible hose 28 to the friction brake cylinder 30.
. Flexible fluid pressure hose 28 and 2‘9 lead from
The pressure transmitted to the cylinder 33 acts
the interior of each of the iìuid couplings I3 and
uponthe pistons 32 andi-X4 to move the brake
I1 to the fluid brake cylinders-30 and 3|, re
shoes 38 and 39 and> expand the .friction lining
spectively. As ‘illustrated in Figs. 3 ande, each V30 44- against the inner surface of thel _ñange' 54V
of Ythese »movable fluid brake cylinders 3l! and 3|
of the drum 5_2 which is rotating in a clockwise
contain a-pair of oppositely movable pistons. The _
direction. The friction between the brake band
cylinder 30 contains the pistons 32 and 34 where- ~
44 and the drum 52 tends to cause the brake band
asthe cylinder 3I contains the movable pistons 33
.44 to rotate with the drumV 52 in a clockwisev di
and`35. As shown in Fig. 3, each of these pistons
rection. The torque thus absorbed by the brake
32 and 34 are secured to the free ends 36 and 31
band 44 is transmitted through the brake sup‘
ofthe pivoted and arcuate-shaped brake shoes 38
and 39, whereas the pistons 33 and 35, as shown
in Fig. 4, are secured to the free ends 40 and 4I
porting member 45 and the key 59to the spindle
49 and tends to move the torque transmitting
member I5 about its pivot. The motion thus
of- the pivoted and arcuate brake shoes 42 and 43. 40 transmitted to the member I5 tends to move the
The outer surface of each of these brake shoes 38
control surface I9 by transmitting the torque ap
andf39 and 42 and 43 are covered with a suitable
brake lining indicated in the drawing as 44. The
plied thereto to the control horn I4 through the
force transmission cable I2.
_,
_
brake shoes 38 andA 39 are pivotally secured to the
At the time that the brake shoes 38l and 39
friction brake supporting member 45 at 4B, where
were expanded into frictional engagement with
as the brake shoes 42 and 43 are pivotally secured
the rotating drum 52, the brake shoes 42 and 43
to the friction brake supporting member 41 at 48.
were not expanded into contact .with the rotating
These brake supporting members 45 and 41 also
drum 53, consequently the brake supporting mem
support the brake cylinders V30 and 3 I-and are each
ber 41 is free to follow the movement of the key
keyed to the spindle portion 49 of Athe torque 50 59 on the spindle 49 by virtue of the spring 64
transmitting member I5 in a manner to be hereinwhich is attached between the lugs 52 and 63
after more particularly described. The coiled
formed on the friction brake supporting members
tension springs 50 and 5I retain their respective
45 and 41. This spring action serves to keep the
brake shoes 38 and 39 and 42 and 43 in the posi-_
driving face of the keyways 6B ‘and 61 against
tion illustrated wherein the respective pistons 32 55 the key 59. It should be noted that the assisting
and 34 and 33 and 35 are each directed inwardly
force of the brake shoes 38 and 39 operates with
in their respective cylinders 30 and 3 I.- '
i
A pair of brake drums or rotatable members 52
respect to the drum 52 and can be smooth and
proportional to the tension applied to the cable
and 53 are supported for rotation on the spindle
22 the same as is the deceleration of an auto
portion 49 of the torque transmitting member I5 6.0. mobile equipped with hydraulie brakes smooth
so that flangeV surfaces 54 and'55, respectively,
and proportional to the foot pressure exerted by
overlie the brake lining 44 formed on the brake
the operator. Movement of the control stick 1v
arms 38 and 39 and 42 and 43.v The outer edge' „ in a direction opposite to the direction indicated
of each of these ñange surfaces 54 and 55 of the
brake drums 52 and 53 are each provided with
a beveled ring gear 56 and 51 which meshes with
_ the beveled gear 58 shown splined on the shaft of ‘
by the arrow A relieves the friction pressure on
_the drum 52 and increases the friction pressure
' on the drum 53, which tends to assist the control
surface I Il in the opposite direction. It is in
tended that when no force is applied to the con
trol stick 1 neither pair of brake shoes will be
and 53 in opposite directions as indicated on lthe 10 forced into contact with the drums 52 or 53; If
drawing by the arrows.
theA operator is holding the control stick 1 in `a
As stated previously, the brake arm support
given position and fluctuations occur inthe ex
ing members 45 and 41 are each secured to the
ternal load applied to the control surface, these
the motor 60. Rotation of the motor 60,' there
fore, produces rotation of the brake drums 52
spindle portion 49 of the torque transmitting
member I5 by means of a key 59. The keyway or
4 fluctuations will cause the fluid pressure within
the `fluid couplings I 6 and I1 to vary andwill
255106,33 56
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the control surface produce. piloti fatigue andare
thuscontrol the boost- forces applied to» the-con
trol. surface.v Of course, any variations in fluid
pressure in the fluid couplings wil-Lbe felt by
undesirable from the- standpoint of` control sys
tem structure. These'suddenly applied loads> fre
quently arise from gusts or fromy rough` air., In
l the operator in a reduced ratio which> is fixed by
the design of the. unit.
»
the modification ofj..my invention..whichiïfhave Y
.illustrated in;Figs.-fI]and 2,.,it’may'bev assumed.
In the event that a boosted forceis not desired,
the energizing circuit of. the electric motor Ellis
that a force producediby' a gust of windissuddenly `
disrupted and the -driving torque producing conapplied to the control surface in the direction in,
dicated. by the arrow C and the operator resists
tinuous rotation of the brake. drums >5,2, `and k53A
is removed. Under these conditions, which may 10 movement of the. control surface in: said direc
tion by applying a. manual force: to the ’con-trol
result. from a. power failure,V it is desirable that`
stick` 1 inV the direction indicated by the. arrow
A. The pressure in the fluid coupling' I6 is thus
increased and »tends to. lock the. friction-bands:
44 of the brake slices 38 and 39' against. thei‘inn'er-
additional loads, beyond the normalcontrol sur-~
face loads, should not be> imposed upon the> pilot
or,~ interfere in any way with the successful, ordi»
nary- -positioning of the control surface.n As
shown in Figs. l and 2, arms-8 and 9. of the torque
flange surface of the: brake drum 52'. .This brake
drum is geared to the' inoperative: electric motor`
69.. Thuis; the, shock load transmitted bythe cable:
transmitting member I5 are. secured to the con
trol cables I2 and I3 and in all cases move with
I2l tothe spindle 4.9" of "the 'torquetransmitting u
membel` .l5 wlfien'N appliedfßby thefkey'. 55E/in> a; .
the cables. As it .was initially proposed that the.
operator> move the control stick 4in thefd'i'rection
indicated by the arrow A, the applied. force goesA
tothe fluid coup-ling IE increasing the fluid pres-`
sure therein and also pulls directly on the cable
-counter-clockwise direction. against the: friction
brakeV supporting member 4'5 is snubbed‘ against: A smallcnn-5
u the inertia of the electric motor.
trol force applied- to the: cable 22` is> all .thatjirs
I2 and control horn I4 tending'to move the. con
trol surfacelû.- The increase in: fluid pressure 25 necessary to produce the snubbing action.v Vifh-ile:
the inertia. of the motor Sil' serves' asn a snubbenl
at I6 if the applied force is suilîcient will be
transmitted to the brake cylinder 3Il> causing the.
brake shoes 38v and 39 to move forcing the brake
it -is apparent that if the control surfaceçvtere:
lining 44 into frictional engagement with theíin
cable 22 would have to carry the wholev load: 'eXf--l
actually moved by these eXteriorlyV applied forces;y
ner surface of the flange 54 on the lorakelY drum`
52 thus- locking the brake drum 52` to thebrake
supporting member 45.v The lug `62' whichis secured. to the brake supporting member 45' can
not move because ofthe frictional. engagement
between the supporting member and the inopera
, tive brake drum 52. However, the brake shoes 42.
_isting on cable. l2..
. illustrated as a Bowden wire, delivers the. push'.-vv
> pull pressure transmitted to the control stickl^
»
and 4'3 are controlled by the fluid pressure. within
the fluid coupling I'Il which is not under pressure
and hence these brake _shoes will not be forced
into frictional engagement with the interior sur 40'
face 55 of the brake drum53. Therefore, inmov
ing the control column 'I inthe' direction A, the
spindle 49 ofthe torque transmitting member I5
will be moved in a clockwisedirection and is free.
.
Fig.. 5 discloses,l a. modification of: this invention:
wherein a push-pull system of control is'A used.
A single force transmitting elementi ‘HL4 which is;
by the operator on to thecontrol horn I4? through
This. fluid. coupling inem'-v
ber consists. of a centrally disposed piston l2.
which is connectedI by' means of the control rod
T3 to the control horn I4’. The» cylinder 'i4 sur-»
rounds this piston 'i2 forming therewiththe. fluid
tight chambers 'I5r and l5 »on either side thereof.
the fluid coupling ‘l I'.
One end of the Bowden wire 'IllY is: secured to; the
cylinder so that the applicationofv manually ap«
to so move with respect to the brake drum` 52V 45 plied force to the control stick; ‘I’ will be tra-ns`n`
mitted by the Bowden. wire “l0- through the fluidA
and brake arms 38 and 39 byreason-.of the ar-v
within the chambers 'i5 and into the brake cyl«l
cuate-shaped key slot B6. of. 2a°. The fluid. inl
inderg 39» and 3l.. The flexible hose 'il
'58
the. brake cylinder 3l is not under pressure and
the `brake bands 42- and 43. are not forcedinto. _conneet the outlet passages leading from the:
fluid-tight chambers 'f5.- and 'IG to the' opposite
frictional engagement with the brake dru'rr'1~l5f3ï,l
sides of the piston of the. brake cylinders 3@ and'
therefore, this drum 53 is freev to rotate relative
3l, respectively. The control rod 'I3'ifs connecti
-to the brake arms 42 and 43. Since the key >59'
ed intermediate the ends of the arm 9" of the;
is retained against the edge of the slot, clockwise
pivoted torque transmitting member l5.: and isf
rotation of the torque transmitting arm I5' will
cause the friction brake supporting member 41` “ movable in the slot T9 of the torque transmitting
arm as this arm movesy aboutI the fixed shaft
to move with the spindle 4'9- andthe operator' has
Iâ'. The torque transmitting mechanism, sche
to overcome only the small tensional force of the
matically illustrated in this modification, islsiin
spring 64 to move'the control surface to the new'
ilar in all respects to that illustrated' in Fig.; y2,
position.
’
,
and similar reference numerals have been: used
'I'he reason that the key slots in the frictional
tcind-icate'their parts.
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y
band supporting members 45 and 41" have-an ar‘
The modification of the invention illustrated’in
cuate extension of 20N' is primarily precaution
6 shows the application of' an air turbine
ary, since the angle a is intended to be equiva
lent to the full movement of the spindle 49 and ’
the pivoted torque transmitting member I5< from
its neutral position. The’ circumstancesI might
be such, however, as to require the pilot to move
the control surface I0 from its extreme limit of
deflection in one position to the extreme limit
of its deflection in the other direction; in which
event, the spindle 49 of the arm I5 would be
required to move through an angle of 2a" with
respect to the locked friction shoes or brake Sup
porting member.
Y
Exterior loads which are suddenly `applied to
Z382 for transmittingA a rotation force: to the two
brake drums` 52" and 53’. ïtis intended that» the
motion of travel of the pistons if:
i9* ofthe»v
huid; couplings IS. and Il' wiil be v
small. inf
going from an .initial to a.
pressure'.
rl‘his» motion may be. limited. by providing stops,
on. the inner: surface of the cylinder, 'as-'illus<
trated, which Serve to transmit .the forces. ape
plied to the control column 'I on to the control
horn I4, in the event of loss of fluid within the
ñui-d couplings._ In the modifications illustrat
75 ed, the ratio of the total force including the as
¿2,406,356
7
sisting force plus -the manual> forcev as trans
mitted tothe controlsurface l0 by either of the
member for each -of Asaid drums, Y each'- saidfplate
member including an V‘arcuately-shaped keyway
cablesV I2 or I3, to the manually applied vforce «to
the cables 22 or 23 is not variable bythe operator
as it is in the copending application but 'ison the-
tending in ' opposite Vdirections from said „ key,
-contrary ñxed by the particular design. It shouldv
frictionally coupleit tothe drum member Lasso- Y
for Vcooperation withsaid key, said keyways ex!
means carried by each of said platemembers `to
be apparent, however, `that >'suitable mechanical `
ciated therewith, resilient means interconnect-f
linkages could be suppliedwhich would give, a
ing said plate -members in such manner as to hold
variable ratio of the forces involved similar to
the driving face of each of said keywaysagainst
those obtained in my copending application to 10
said key, andfmeans' connected in said 'manual
which reference has been made above.
force Vtransmitting means' for actuating said fric#
According t0 the provisions of the patent stat~
utes, the preferred forms of my invention have
been illustrated and described with the under
standing, however, that the devices are illustrat
ed in their simplest form for the purposesïof
clarity and itis intended that many variations in
the design `may be made without departing from
tion coupling means.
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2. In a device for supplying a boost force to aid
in positioning the control surface of anaircraft,
the combination comprising, . manually' actuated
means for transmitting a manual force to said
control surface to effect motion thereof, fluid cou
l pling ,means' included .in said _manually actuat
, the scopev of this invention. As a specific example,
a ñuid pressure switch could be installed which 20 ed means, a spindle, ra key carried by saidfspindle,
-meansrconnectin'g said .spindle in` vsaid manual
would energize 'thefmotor only when' the.~ initial
ñuid pressure in the couplings had risen to acer“
tain desired value. Thus, the motor would-run
only when torque was desired. It is also apparent
that the small beveled Vgear vcan be connected'to 25
the/motor Ybymeans of a uni-directional clutch so
that the motor would deliver/torque in only one
direction. This would', permit the brake support-Y
ingunit to be connected directly to the spindley
49 of the torque transmitting member , l5.,v With
this arrangement, it would be‘necessary to >rc
tate Ythe drums 52 and 53v as well as the small
«beveled gear in the event of failure of the power
system. It is also apparent that a single drum
could be rotated by an electric motor, the »direc
tion of rotation of which would be controlled by
the individual fluid couplings, particularly if the Y
force transmitting`means >1305111101015’ said boost
force to saidcontrol surface upon rotation of said
spindle, a pair of drums mountedY to rotate on
said spindle, means for rotating saiddrums in
opposite directions, a plate member foreach of
said drums, eachrsaid plate member including an
arcuately-shaped keyway for cooperation with
saidvkey, said keyways extending in opposite di
rections from said key, means Ycarried ,by each of
said1plate members to vfrictionally _couple it to
‘ the drum'member associated therewith, resilient
»means interconnecting said plate members in
such manner as to hold the driving face of the'
keyways in said plate’vmembers against said îkey,
_ fluid motor means for actuating said- friction cou
pling means, and conduit means connecting said '
ñuid motor means to said fluid coupling means'.
3. In a device for supplying an assi-sting force
through friction discs because the friction discs
work equally well in either direction Whereas the 40 to aid in positioning a control surface of Van air
craft, the‘ combination of _afpivoted- control sur
brake bands disclosed, operate better in the man
torque were to be transmitted to the »spindle 49
ner illustrated. The disc type of clutch unit may
be preferred under certain circumstances to the
type illustrated inthe drawing since an inherent
face, means for transmitting a manual force to
actuate said control surface, a piston and cylin
der interposed in said force transmitting means,
advantage of the disc is that they are practically ` 45 a spindle, a key carried thereby, an arm ‘secured
free from grabbing actions in changing atmos~
phere conditions, thus assuring smooth uniform
assistance. VThe particular disc type of clutch
to said spindle, meansl connecting' said arm in
said forceV transmitting meansV to supply said as--v
Asisting force to- said control surface, a. pair `'of
drums rotatably mounted on saidv spindle, means
to which VI have referred are well known to the
art and are yused as brakes on aircraft. The in 50 for rotating said drums in oppogsite‘directions, a
vention herein disclosed may thus be practiced
otherwise than specifically described or illuS-,y
trated and still remain Within the scope of the
appended
claims.
.
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plate member foreach of said drumsfsaid plateY
members being journaled onY said spindle, a key#
way in each vof, said 'plate members vwider than
the key carried bysaid spindle means connect
The invention described hereinmay be manu 55 ing Isaid plate members in such manner as to hold
the driving face of the keyways therein against
factured and used by and for the Government of
said key, means carried byeach of said plate`
the United States of America for governmental
members for frictionally, couplingY said jdrum
purposes Without the payment of any royalties
members thereto, hydraulicV means to actuatel
thereon or therefor.
60 said couplingmeansand conduit means connect-V
ing said hydraulic means to saidY cylinder, where
1. In a device for supplying an assisting force
to aid in positioning a control surface of an air
by upon application of manual force the increasedv
craft, the combination comprising, manually ac
pressure in said cylinder will cause said hydraulic
means to actuate said frictional coupling means
tuated Ymeans for transmitting a manual force
to said control surface to effect motion thereof, 65 to thereby transmit a portion of the inertia of
one of said rotating drums into saidforce trans#L
a spindle, a key carried by said spindle, means
mitting means through its associated plate meni
connecting said spindle in said manual force
ber, spindle and arm to supply, said assisting
transmitting'vmean's to supply said assisting force>
upon rotation of said spindle, a pair of drums
Y
vJESSS.
DAVIDSEN.
mounted to rotate on said spindle, means for ro -70
tating saidV drums in opposite directions, a plate
force.
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