US2130929A - Stabilizing equipment for vehicles, particularly ships - Google Patents

Description

Sept. 20, 1938 ROCARD 2,130,929

STABILIZING EQUIPMENT FOR VEHICLES, PARTICULARLY SHIPS Filed April 16, 1955 Patented Sept. 20, 1938 UNITED sT TEs Mamaans;

Yves Andre Rocard, Paris, France; assignor to" r Pollopas'Patents Limited, London, England mutation April is, '1935;='sefi51'Nt. 16,69 9

In' France April' 18, 1934 1 11 Claims. (Cl. 114- -122-) My invention relates to stabilizing equipments for vehicles, particularly ships, and more 'particu larly to stabilizing equipments adapted to damp ing the rolling of the ship. The stabilizing equip- "ments of this kind known in the-art comprise a device for supplying a stabilizing couple, said device being designed for instance as a gyroscope,

a movable weight or the like, and a device for controlling the value of the stabilizing couple, the controlling device operating automatically" or nonautomatically.

The rolling of a ship is ruled by the following differential equation:

of inertia of the ship about the longitudinal axis passing through its centre of gravity, M( t) the couple of rolling acting upon the ship and X the, stabilizing couple. The problem tobesolvedby any stabilizing equipment resides in determining the law of the variation of .2! so as to damp as be-t'ransformed'into much as possible the rolling of the ship.

Some stabilizing equipments known in the artQ- are based on the change of thesenseof the angle of I rolling 0, for instance by assuming Y Ka Now M (1.) contains a term of the form mghf a) 0,

.m being the mass of the ship, g the acceleration of gravity, r is the radius of curvature of the metacentric arc and a is the distance from the center of gravity, and ra, the metacentric distance. The term referred to represents a return I couple. Thus it follows from Equation (1) that under these conditions only the natural period of the ship can be changed by the control X=K0.

In other stabilizing equipments known in the art'the control is basedon the velocity of rolling manner that the velocity of the precession .o fl a 4 sense is instantaneously changed when y dt vanishes. Putting it will be seen from Equation 1) that at 'certain *laws of change of M(t), for instance at the 00 stabilizing gyroscope is held constantfwhile its,

currence of beats of two systems of swell, the introductionof a termlbeing a function of will cause anomalous amplitudes 0 which may causeaccidents. Besides this any stabilizing equipment controlled in response to the angle of rolling am the angular velocity I it' s: I 1 requires for itsoperation thata rolling is already existent in order that the stabilizing action can exert a'damping effect; 1

From the foregoing it will be/seen that control systems based on the angle of rolling or its time derivatives do not afford a perfect solution of the problem.

In another stabilizingxequipment known in the art comprising a stabilizing gyroscope the control isc'arri'ed out'by putting -X=M(t). By doingfiso'the influence 'of' the rolling couple is eliminated but the differential Equation (1) Will In the movement defined by-this equation there is no return force at all toward a position of equilibrium which would, act upon the gyroscope. Whenever during a plurality of periods of swell the ship remains in an inclined position,

a fcha'n ging of condition will "occur when the movement of precession reaches its extreme point sothat'the'device intended for compensating the rolling tends-t0 destroy its own effect.

It is an object of my invention to provide an improved stabilizing equipment not subjected to. the drawbacks of the equipments known in the art which are discussed hereabove. Inorder to accomplish-thisIjprovide an automatically operating control means for the device supplying the stabilizing couple, said control means being designed in such mannerthat at any time the stabilizing couple is composed of two terms or components the first-.ofwhich is substantiallyequal and opposite to the couple of rolling, while the seoondtermis a function of the angle of rolling or its time derivatives "or integrals. The first component 'may depend on a time. derivative of'th e" couple of rolling or of the alternating component thereof. 1 a

In a' stabilizing equipment" according to my invention the"-'aut'oinatically operating control means exert on the device supplying the stabilizmetrical device for measuring the rolling forces.

7 ;;chosenr Y ing couple an action comprising a component being a function of the couple of rolling and its time derivatives and integrals and a second component being a function of the angle of rolling and its time derivatives and integrals.

Other important features and objects of my invention will be apparent from the following descriptio'nand' the' drawing.

In the drawing affixed to this specificati'on"and forming part thereof some embodiments of my invention are illustrated diagrammatically b t way of example. I 1

' In the drawing:

Figs. 1 and 2 are diagrammatic side and front views, respectively, of a ship provided withi devices for measuring the couple of roll-ingr Fig. 3 is a wiring diagram illustrating '=the op eration and connection of the measuring de-".1- vices shown in Figs. 1 and 2. v V p s Fig. 4 is a perspective view of a 'devic'e for measuring the angleeofrrolling 1 Figs. 5 and 6 are wiring diagr-ams ,of,- devlces.: for forming time derivatives and integrals of the couple or angle of rolling measured by the devices shown in Figs. 1 150 4.

"Fig; 7 is a diagramizofva mompletemtabilizirigxv equipmentiwand control :means; accordingito m invention; iniwhichrthe stabilizing'icoupleris-xsup plied by the reactionofithe: output of two. pumpsv-x;

Fig. 8 is a modified embodiment of a mano- Fig. 9 is a wiring of arrembodiment aim invention provide with manometrical deYiGeSi aS 1 shown l-n Figlfifipii V Fig. 10 is a diagram ati-c' perspectivewiew the front' portionof- -a ship providedwvith a device fordirectly measuring r d6 fir:

Before: m'ore iuilyt describing: the invention @imc: connection with the drawing :it ;-,will bezuseful 1130*?2 explain ':'shortly the mathematical :itheory-sofithe i" devices producing the stabilizingicouplegsince byiz:

doing so the understanding. of my invention will be considerably facilitatede In a gyroscope the counteracting couple is given by-the iolldwingterm:

J fleeing the moment of =inertia-of the rotating body, :W-its angular; velocity-andB :the angleof;

precessionr By-introducing this term:into- -Equation (1) the;followingequatiomis;obtainedzii'- I' being the; moment of inertia: of themembrs subjected to' precession; KB being an elastic "re-t turn :couple f' required "for restricting the oscili: lations -of precession; to j the neighbourhood "of "B=" o' andI Y being the couplebeing produced by I the device controlling the movement.of .'.preces.-.. sion. In orderito. obtain-a suitable control means the. value of zthe couple Y ls'hould be suitably;

, second;

By eliminating B from the Equations (2) and (3) and by putting Y: Y1 Y3 is v(composed .of*=a ,termequaltoyMU) and ;an.- other termcontainingthe angle ,0 and itsiderivw ativesze If a device different from a gyroscope :is .used..;, for: producing h s ab l ng coup e 17116155841116 result will be obtained, viz, an-angle. of. rolling 0 defined by a linear differential equation which is independent of ..the time and represents a, damped movement:" In this case also the anti rolling equipment is controlled in response to a va lue dependinguponthe couple and angle of rolling and their derivatives and integrals; In -aparticularly =iriteresti1ig embodiment of' myinventionthstabilizing couple is produced by a practicallyinertialess device; f or instance by the reaction w the -output or the suction of pumps preferably arranged-bathe ship "such as those I of British Patent'to' Bar -403,211, Dec. 2131933, sotthatthstabilizingcouple will depend on the output 'of' the pumps which' in' their turn may be controlled i n-an inertialess manner; Thus in fv theequation v the'zcoefii'cients .:a and hmay be determined in: the following manner: One regulates a to the desired value in order that-the couple a0 is equal to the maximum couple which may be produced by the anti-rolling device when 0 is oi a con venientwalu'e, say,ffor.example,'30}

one regulates b to ,the desired value in order that th'couple is equal to the maximumicouple which may be produced by the anti-rolling devicecwhenr- 'l g dt if of a convenientivalue', -say, 5:of rotation per-*2 ll-Ien'cje it will be sufficient to measure the quantity and to-controlthe output of the pumps proportionallyto this expression.

rte ferring now to the drawing and particularly to Figs. 1 and 2, I, 2, 3 and l', 2, 3' are two sets of manometers arranged below the water line at opposite sides of a ship S, respectively. Preferably themanometers arearranged at points in which the radiusof curvature of the cross section of the ship passes at one side of the centre of gravity G of the ship.

I The manometers are connected with each other in such manner that the effects of manometers arranged atthe same side of the ship are added to each other, while the efi'ects of manometers belonging to diiferent sets counteract each other, so that the resultant efiect is proportional to the couple of rolling.

,An embodiment of such a connection is shown inFig. 3 in which each manometer actuates the sliding contact of a potentiometer 4, 5, 6 and 4',

5'; 6* each of which is connected to a current supply 1, 8, 9 and 'l', 8, 9', respectively. The potentiometers 4, 5, 6, and 4', 5', 6' are connected in series, respectively, the two sets of potentiometers being connected in opposition to each other so that the voltage arising at the terminals In, II will be proportional to the couple M(t).

Referring now to Fig. 4, a small gyroscope is shown for measuring the angle of rolling 0. The gyroscope comprises an outer frame provided at opposite sides thereof with tapered studs 8| engaging suitable holes provided in fixed memhere '62 forming part of the ship. 63 is an inner frame arranged substantially normally to the outer frame and provided with tapered studs 64 engaging suitable holes on the inner side of the frame 60 with their connecting line crossing the connecting line of "the studs 6| at a right angle. In the inner frame 63 the flying body I 2 of the gyroscope is rotatably mounted by means of a shaft 65 to the lower extension of which the sliding contact 66 of a potentiometer l3 connected to. a current supply I4 is secured. The potentiometer i 3 is rigidly secured to the body of the ship so that the position of the sliding contact 66 will depend on the angle of rolling 0. In consequence thereof the voltage arising at the terminals l5, l6. will be proportional to the angle of rolling..

In order to form from the voltages obtained by means of the devices illustrated in Figs. 3 and 4 time derivatives and integrals, voltages proportional to the couple and angle of rolling, which are obtained for instance by means of the devices shown in Figs. 3 and 4, are fed to an amplifier, for instance a grid valve in the output circuits of which suitable impedances such as ohmic resistances, inductances and capacities are arranged, from which a voltage may be withdrawn representing a time derivative or integral of the rom the formulae 7 In order to accomplish this voltages applied to the input or a linear function thereof.

Referring now particularly to Fig. 5, a connection is shown supplying a voltage determined 7; 2 v I 01" i i dMt the terminals H), H

of Fig. 3 or l5, I6 of Fig. 4 are connected to the input terminals l1, l8 of a grid valve l9 shown as a screen grid valve, in the plate circuit of which a resistance 20 proportional to the coeflicient a and an inductance 2| proportional to the coeflicient b are provided, so that the voltage arising at the terminals 22, 23 will be that indicated above as determined by the constants.

In order to obtain a voltage proportional to the time integral of the voltage applied to the input of the valve a condenser may be arranged in the output circuit of the valve the capacity of which corresponds to the numerical coeflicient of the integral. Since the anode circuit is proportional to the value A or M(t) applied to the grid of the valve the voltage arising at the terminals of the condenser will amount to lf t 11 C 1 The anode voltage of the valve I9 is fed in Fig. 6 by the current of a saturated valve 25 instead of which, if desired, another device may be provided having a practically infinite resistance at varying currents.

In order to obtain a term proportional to the second derivative of the input voltage of valve IS the voltage arising at the terminals of the inductance 2| may be applied to the input of a second valve, the anode circuit of which contains a suitably chosen inductance. It has heretofore been pointed out that an anode current flows in the anode circuit of the tube 19 which is proportional to the initial potential pressed upon the grid. Furthermore, as also pointed out, a potential appears at the inductivity 2| which is proportional to the first difierential quotient of the anode current, and thus also proportional to the first differential quotient of the initial potential, When this potential is transferred as ini-- tial potential to a second tube, the anode circuit of which is in turn provided with an inductivity, then a potential must appear at this inductivity which is proportional to the first differential of the initial potential of the second tube and thus also proportional to the second diiferential quotient of the initial potential of the first tube.

As will be seen from the foregoing by the means described in connection with Figs. 3 to 6 any voltages may be obtained which are linear functions of the couple and angle of rolling and of their time derivatives and integrals of any order. The voltages obtained in this manner are to be applied to a relay influencing the control of the device supplying the stabilizing couple. An embodiment of this arrangement is shown in Fig. 7 in which the stabilizing couple is supplied by means of two pumps 24 and 24'. The measuringdevices correspond exactly to those shown in Figs. 3 and 4. The voltage delivered by the gyroscope 12 which is proportional to the angle ofrolling 0 is applied to a valve 25 connected in t ii t f volt g f p ie we:

" man ters 2,.3 and jl'. -,l2','. 3; which is 'pro-w porti al to theflcoupl'e of rolling Md) is. applied 1 td'the input'of valve inthe outputofwhich, t; io n,,28.,of= the] ohmic resistanceis cond, ,the'ratio-of the sections 2-1., 28. being. so-

' hat the voltage. .arising' at the terminals 1, seq'ualto thequantity 15d A U )'-lit his t e a p ie t am fie x -r a 3| controlling the slides 33 33 ef-the pumps 124,. 24', respectively.

It is clear that the coefficients of those memgi bers which are proportional'to the angle of rolling and its derivatives, can be influenced by varying. the;sens'itivity of the amplifier 3|. That the ship.s own period, on the other hand, isdependent-upon L-these coefiicients is a result of the fact @sthatlthese coefficients enter the-differential equa "'tion which governs the rolling of the ship; Consequently the period of the ship may be controlled by regulating the sensitivity of the amplifier. At 32 I have shown diagrammatically a device by g means ot which the sensitivity of the amplifier may he regulated,

Re rrin'g nof I to Fig.3, ,a modified emlb'odi f ment of a manon eter is shown whichjmay be used for each of the manometers I, 2, '3, 2', :3fj i -shown in Figs. 1 and 2. '36; is an electrically conductive sleeve secured to; the; wall of the ship. 31 is'a diaphragm mounted in, the front portion of the sleeve 36. Preferably the diaphragm consists of a resistive Aland flexibleymaterial such as stainlesssteel. The

' diaphragm'forms the movable armature of a condenser, the fixed armature 38' of which is connected by means of a connection!!! to anf intake terminal of a device 4|, for instance an aniplifi'er or the like transforming the variations of; capacity ofthe condenser 31, 38' into a correspondi'ngly varying voltage which may be with-,

drawn fromtheoutput terminals' 42. The elec-} trical connection of the armature or diaphragm 5Q 3'lj to the other terminal of the device, isinade by means of the sleeve 36. The manometer shown in Fiig; 8 is entirely inertialess even at veryrapidly varying pressures. The, sleeve '36 and the diaphragm 31 are arranged in such mannerthat fiq they dojnot troublethe linesof flow of the' water flowing; along the sides of the ship.

Fig. 9 isja diagram of a connectio n in which manometers according to Fig. 8 areused. The manometers designated by I, 2, 3 and l, 2; 3' are arranged at opposite sides of the ship Sin "similar manner as shown in Fig. land are connected in pairs to amplifying devices '43, 44, 45, each corresponding to the device 4| shown in -Fig. 8, in such'manner that they counteract each 6d,,pther, so that each device 43, 44, 45 supplies a ""voltageproportional to the differenceof the ac tions of the manometers l, I, 2, 2 3, 3 or to the 'couples of forces exerted in the 'lines'l, l,

232', 3'3, respectively The voltages delivered 70 bythedevices 43', 44, 45 are superposed by'means vs..lmeerfiPn i H-P M and t e v t e 7 constant term and r in egrals If-. th m th r; mpi the rolling operates p'r'aa'mauym an inertialess man.- ner the device 41 may be dispensed with. If desired, the couplingofthe manometers may be carri-edout in a different manner and particu- 5 larlythe manometersand their associated parts may be designed in such manner that the presu e m ga att-themanome ers siipu ipum byanadjustable coefiicientg V '148 is a device for masuring-the'angle of-r 11- ring similar to" thatfshovvn in Fig 4 fan'd 49-isa: devic'e for"forming time derivatives orintegral s; of the angle of rolling or' linear functions thereoi :as more fully de scribed herealdove' and 'asfi llu sitrated in Fig, 1'7, is a relay combining the voltages 'supplied'by the devices-41 and 49" and feeding the combined voltage to Y the control ole vice '5 l corresponding for instance u to the device :3lotFigs7i v t L j A very important embodiment of my invention" 20. in which th'e control is -considerably;'s'impli'fied is the following;

-Beit assumed" that the device for dampingffthe trolling operatespr'actically without-;-inertia which maybe obtained in the-mannerdescribed above 5, by using centrifugal pumps or; the like; then it" will be sufiicient to carryout the control accord 5mg t'o thefollowing iequationg v do on M r Now the only constant term .oi'f-Mdyis derived; from mg(ra) -,0 and corresponds to a perpetual inclination of; the, ship which is compensated; by introducing the. return couple 416 into the ;anti.-- rolling couple. The devices such as 43 to -.45 v 3531 in Fig. 9 are slightlymodified inthe-rnanneredescribed hereinafter .so as; to ea mate supply the constant term o f .M (t)f. The remaining-terrn M d); constitutes a 'couple which -iowing to its, alternating character, tendstebring-theship-1 back .into, its, verticals-position; or imibr-ium; Thus it will be: seen that the couplefor-dam ping the; rolling may .be:controlledaccording tog-thek simplified equatioh y v n XT'M WT EZ In order to suppress in thejputput circuits of the devicesf43 jto 45 the constant term oft/[(15 a capacityhavi an i imp snemi; the

H I H e current may' be iriserted infany circuit ca r'ying acurrent;proportional to'M'(t),'-'the capacity being" chosen so that thf condenser is permeablefor an alternatingterm or mgt y evenpr the lowest frequency, 1 In calculating the ca 'acity of the c ndenser obviously the im edam sp w npu l d o p gc mef r: the devices} 433m 145 should flee, tale err ii nto. con sider ationh Further fin this case t e an le of rolling ejneed njot be measured sinceiti is sum 0;,- j ni WW i sdefi at ich m 'j ne fis m l m nn r ass stance' b'y means ofthedevi'ce shown -in Frg' e in which 52 is a. small gyroscope connected to he; shi i i Su 'amahfi ha i an c rr out'only a movement "of precession; besides the; rolling movement. The movementof precession is counteracted by a strong ,;rspring 53 and the small displacements occurring in spite of the, counteraction of the spring are transmitted to" the sliding contact of a potentiometer 54 conq siiq. e Earlies slip at. at th t rm .for measuring the couple of rolling nals 5,5 a voltage will arise the ent wh ch prop r o a t variable compof Inthe embodiment operating according to this principleand employing a practically inertialess device for'damping the rolling the device shown inFig-g Q'maybe simplified by omitting the device 41 and replacing the devices 48, '48 by a single device without providing any devices for forming-derivatives or integrals. v

The following explanations relate to the minimum'number of manometers required for a sumcient measurement of M (t').' Obviously the measurement need not "aifford the highest possible exactness, a measurement being suflicient which practically-coincides with the couple M(t) and always: has the same sense of variation. Two

1 manometers (one at each sideof the ship) are entirely insufficient but four manometers (two at each'side of theship) will 'afiord a practically suificient' measurement, "If six manometers (three at each'side of the ship) are usedthe exactnessof themeasurement will amount to 1% provided that the pressure exerted on the wall of theshiphas a sinoidalv distribution. In any case in iiifierent cross' sections of the ship sufiicient measuring devices must be provided for measuring the couple exerted by the sea.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

In the claims affixed to this specification no selection of any particular modification of the invention is intended to the exclusion of other modifications thereof and the right to subsequently make claim to any modification not covered by these claims is expressly reserved.

I claim:

1. A stabilizing equipment for ships comprising a device for impressing a stabilizing couple upon the ship, means for measuring the couple of rolling and the angle of rolling, means for forming time derivatives and integrals of the couple and the angle of rolling, means for forming a linear function of the couple and angle of rolling and of their time derivatives and integrals and means for controlling said device to this linear function.

2. A stabilizing equipment for ships comprising a device for impressing a stabilizing couple upon the ship, means for measuring the couple of rolling and the angle of rolling, said means for measuring the couple of rolling comprising two sets of manometers arranged at opposite sides of the ship, respectively, and means for combining the efiect of manometers belonging to the same set and of counteracting the effect of manometers belonging to different sets, means for forming time derivatives and integrals of the couple and the angle of rolling, means for forming a linear function of the couple and angle of rolling and of their time derivatives and integrals and means for controlling said device in response to this linear function.

3. A stabilizing equipment for ships comprising a device for impressing a stabilizing couple upon the ship, means for measuring the couple of rolling and the angle of rolling, said means comprising two sets of units each comprising a manometer. a potentiometer and a. movable contact operated by said manometer, the manometers of said sets being arranged at opposite sides of the ship, respectively, and the potentiometers belonging to the same set being connected in series, the potentiometers belonging to diflerent sets being connected in opposition to each other, means for forming time derivatives and integrals of the couple and the angle of rolling, means for forming alinear function of the couple and angle of rolling and of their time derivatives and integrals and means for controlling said device in response to this linear function.

4. A stabilizing equipment for ships comprising a device for impressing a stabilizing couple upon the ship, means for measuring the couple of rolling and the angle of rolling, said means for measuring the couple of rolling comprising two sets of manometers arranged at opposite sides of the ship, a movable diaphragm in each manometer, two sets of condensers associated with said manometers, respectively, each condenser comprising av movable armature formed by the diaphragm of the associated manometer, and means for combining the effect of condensers belonging to the same set and of counteracting the effect of condensers belonging to difierent sets, means for forming time derivatives and integrals of the couple and the angle of rolling, means for forming alinear function of the couple and angle of rolling and of their time derivatives and means for controlling said device in response to this linear function.

5. A stabilizing equipment for ships comprising a device for impressing a stabilizing couple upon the ship, means for measuring the couple of rolling and the angle of rolling, said means for measuring the couple of rolling comprising two sets, each comprising at least two manometers, arranged at opposite sides of the ship, and means for combining the effects of manometers belonging to the same set and of counteracting the effect of manometers belonging to different sets, means for forming time derivatives and integrals of the couple and the angle of rolling, means for forming a linear function of the couple and angle of rolling and of their time derivatives and integrals and means for controlling said device in response to this linear function.

6. A stabilizing equipment for ships comprising a device for impressing a. stabilizing couple upon the ship, means for measuring the couple of rolling and the angle of rolling, said means for measuring the angle of rolling comprising a gyroscope, a potentiometer and a movable potentiometer contact operated by said gyroscope, means for forming time derivatives and integrals of the couple and the angle of rolling, means for forming a linear function of the couple and angle of rolling and of their time derivatives and integrals and means for controlling said device in response to this linear function.

7. A stabilizing equipment for ships comprising a device for impressing a stabilizing couple upon the ship, means for supplying electric voltages proportional to the couple of rolling and to the angle of rolling, means for amplifying said electric voltages, said amplifying means comprising in their output circuits an impedance supplying a voltage proportional to a linear function of said voltages proportional to the couple and angle of rolling and of their derivatives and integrals and means for controlling said device in response to this linear function.

rents at voltages, proportional:l to. the couple 1 of rolling and ,t o:.the angle-:of ro1lin'g;':means for amplif in wsaid, electric. voltages, said ampliiying means; comprisingv in their/output circuits-an 5 impedance supplying .a voltageproportional toa linear junction of said:voltages proportional to the couple and angle of rollingiand of-their derivatives and. integrals, said :output circuit in" cludinga condenserand a saturated .valVefor 1 0 supplying theanode voltage of .said ampliifying means and means for controlling saiddevioe in response to this linear function. ,v 9. A stabilizing equipment for .vehicles comprising a device for impressinga stabilizing cou- 15 ple upon the vehicle, said devicefconsisting-of means for. measuring the couple :and angleof rolling and forHforming-stime"derivatives and nt rals ,of saidcouple and angle ofrolling and comprising aggyroscopa. andautomatically: op-" 29 erated means associated with said gyroscope-for cqn ollingwsaid device. in such manner-"as to provide, two vcomponents the first of which depends on the derivativeland theintegral of the couple. of rolling,- while'the second component is 2@ afunctionnf the: angle of-rolling, itsi i'ntegral and its second derivative' 4 Y v 10.; A stabilizing equipmentsfor ships comprising anti-roll.,force-producing meanspand means efi ect in the respective series; and" con;-

pling the manometer-series in opposing rela-I 'tion'shipto each other and also ie'mbracingv-said Iorce'mroducing" means. V 10 I: 11; Astabilizing equipment 01" ship's comprisin'g anti-roll force-producing meanswhich constitutes a stabilizin'glcouple', and nieans ior'cgntrollingsaid stabilizing"couple' 'consisting oij the p 7 following elements: plural manometric seriesin 1 5. which ffthe individual manometers are serially nct, c'ally' connected on the respective sides oi the ship "and which series are" electrically eonn'ectedacross"the 'shipsoas to counteract each other and establish a couple of ro1lirig1, a gyroscope having electrical regulatingmeans "joined injsaid c (gs-co ne tion of the madman; s a to measure, the angle of mums; and means which, is connected tosaid" stabilizing couplehand which isresp'onsive to electrical current variations origi- 25.; hating at said regulating means.

YVES' ANDRE" RQCARDij

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