Патент USA US2406173код для вставки
Aug. 2o, 194e. „v_-T; siTEPHENs V2,406,173 ’ SERVOIOTOR AND CONTROL -THEREOF 4 Sheets-»Sheet 1 0H uw, , wfrQsfraaPHBNs m Í sERvpMoToa AND coNTnoL THEREOF Filed April 1e, 194:',> - fr Imm@ fi 4 sheets-sheet 2 , ` ` _ Aug. 20, 1946. w, T_ lSTEM-WENSv 2,406,173 SERVOMOTOR AND CONTROL THEREOF Filed April 16, 1943 ‘ `4 sheets-sheet 4l A, 147 ' gwvmw» W. T. STEPHENS _ www“, 3 Patented Aug. 20, l946- y 2,406,173 ~ untreu STATES PATENT: OFFICE 4SERVOMOTOR AND CONTROL _'.liHEREOF l William T. Stephens. Cleveland, Ohio, assignor to ' Hydraulic Control Engineering Company, Cleveland, Ohio, a corporation of Ohio ' Application April 16, 1943,'ser1a1No. 483,312 13 Claims. (C1. 1214-41) 1 2 This invention relates‘toi a hydraulic control system, and more particularly to a hydraulic sys vtem and control valve thereforfespecially for op therefor and a degree dial for'indicating the po erating a pivoted control member such as an air sition of the valves; craft aileron, rudder and wing flap, or a vehicle steering gear. An object of the invention is to provide a hy draulic control apparatus whereby the movement of the pivoted member is positive in operation without hunting or over control. The hydraulic Fig. 8 is a fragmentary front elevation of the , control vvalve illustrating the .operating handle l ` . I Fig. 9 is a fragmentary view partially in cross section taken on line 9--9 of Fig. 8; and . 'Fig l0 illustrates the double acting hydraulic motor‘partially broken away to show the piston andv piston rod construction, . Fig. l illustrates a diagrammatic lay-out of the -hoist ormotor used for actuating the pivoted system as a whole, showing- one‘manner of 'oper member is of the double acting 'variety wherein y ating the pivoted aileron or other pivoted surface. hydraulic fluid under _pressure is introduced be In this figure numeral I denotes the hydraulic hind one side of the double acting piston and the control valve coupled by suitable pressure lines to hydraulic fluid on the other side of the piston is 15 a fluid accumulator 3, hydraulic‘fiuid supply tank exhausted therethrough into a valve mechanism 5 and pressure pump 1 for maintaining the hy provided with compartments or chambers of the draulic iluid at a pressure suillcient tov operate identical volumetric capacity as the portions of vthe fluid motor 9. .As shown in the drawings, thel motor cylinder on either side ofthe double the hydraulic'motor'S may be coupled through af acting piston. ' _ f ' 20 chain _|85 or other power transmitting medium to Another object of the invention is the construc sprocket wheels, one of which has a shaft on tion of the control valve whereby hydraulic iluid ' which the aileron or other surface II is secured. is applied to either' side of the hydraulic motor In addition to the novelty of the system for to move the piston rod thereof to any desired de controlling or moving a vpivoted surface, them-_ gree and to maintain this fixed position with aß'vention hereinafter described includes the hy ‘assurity‘ until the operator desires to change the draulic- control per se designated by numeral I: setting thereof. It will be appreciated by those The control Valve as shown in Fig. 2 consists in the art that it is essential that a pivoted lconof a center -rotatable valve plug I 5 mounted with in a cylindricalrotor I1. . The rotor is supported trol surface of an aircraft must be moved an ex act amount so that there is no overor under 30 in spaced cylindrical bearings I9 and 2| having movement of the pivoted member and that any enlarged spaced annular flanges> 23 and 25 _re tendency of the pivoted member to flutter must spectively. These enlarged flange members are be suppressed. . peripherally jointed by an enlarged cylindrical casing 21.» The‘rear endfof the valve- defined by , » In the drawings:` - Fig. 1 is a diagrammatic lay-out of the system, vat the cylinder bearing I9 is closed by a gasketed end including the control valve, the hydraulic double ’ plate 29 while the rotor I'I is secured in the valve actingmotor and the typical means of moving the assembly by means of a set screw 3l whose inner end rides within an annular groove 3U formed Fig. 2 is a longitudinal, vertical, cross-sectional Y . adjacent the end vof the valve plug I5. _ view of the control valve per se, taken on line 2_2 40 Rotative movement is ~imparted to- the inner y valve plug I5 by means of a vertically extending of Fig. 1 and showing the various fluid passages pivoted member; ' ' therethrough `and the operatinghandle whereby ~ these passages‘are . tive relation; _brought into desired coopera Fig. 3 is a transverse vertical section taken on Fig. 4 is a transverse vertical 'section> >taken yon une 4_4 ofFig. 2; ’ Fig. 5 is a transverse vertical section taken Aon lineß-S of Fig. 2; , " Y Fig. 6 isa transverse vertical section taken on line 6_6 ofFig.2: ' ' . y. Fig. '7 is a horizontal cross-sectional view taken on line'l-Íl of Fig'. 2 at the rear-portion' of the i valve; flange 35. The outer periphery of this flange is supported'within theouter end of the -leftïhand cylindrical' bearing 2I with an annularseal 31 abutting the flange 35 for the purpose :of forming « line 3--3 of Fig. 2; I handle 33 having an-annular inwardly-'extending l , ' a hydraulic seal. As shown. the lower portion of,l ~- the handley 33 carrying the inwardly- extending flange is. bolted to the'y rotary plus l5. LYins'be-ç. Q ' tween the outer `end'oi' Íthe cylindricalbearing'ZI V i y j and the nat portion ÍoIf the handle and ,surround-> ing the ilangeilis adialplate `45 having an arcu ate slot.“ therein to provide a lost motion> con nection, as will 4be hereinafterdescribed. yThe- dialplate 4I is loosely mounted on the outer sur-> i.’ f , y " 5 2,406,178 a ~. ~ 3 4 , l face of flange 35. Pin 4| ' amxed to the inner , The radial passages |00 and I|5 which lie in surface of `the'handle 33 extends into the arcu ate >slot 43 of dial plate 45. Directly above the spaced, parallel relationship to passages 85 and 91 are also diametrically opposite and join bores arcuate slot the dial plate' is turned at right an- . y99 and III, respectively, to the outside of the ' gles to form a-taperedl pointer 41 having a groove valve plug I5. Radial passages |39 and |43 ly ing in spaced parallel relationship to passages 85 or guide line therein for registering with suitable indicia' carried by the dial ring 39. As shown in detail in Figs. 2 and _4, the cen' tral portion of the control valve lying between the enlarged flanges 23 and 25 is provided lwith a lower cylindrical ñller segment 55 that is held in fixed relation with the cylindrical casing 21 by means of keys 51. _'I‘he enlarged central part- . and 91 and |00 and I|5 are also positioned dia-metrically opposite to each other and join bores III andIOI, respectively, to. the outside- of the- ' valve plug I5. ABore III is plugged at its outer end by screw plug ||3. This series of bores and passages together with the previously described bore 8| and its associated passages 19 and 85 . of the rotor I1 is supported by and has a close fit ' ' make up the fluid passages through the-valve with this cylindrical segment 55. The rotor also carries a baille or abutment 53 keyed there in and dividing the upper open chamber between the side edges'or stops 59 and '6| of the cylin dricîal segment 55. When the rotor I1 is ro tated to the right or left by the edges 59 and 6|. vided with longitudinal adjacent the rotor I1 its movement is arrested The member 55 is pro iiuid grooves 63 and 65 and formed below the -oblique stop surfaces 59 and 6|. Hydraulic fluid' from the accumulator 3 enters the control valve through inlet 69 (Fig. 3') having a horizontal passage 1| ~passing through the bearing wall I9 plug I5. . In rotor I1 lands ||9 and.|2| (Fig. 4) separate the ends of the circumferential grooves I|1 and y respectively. | I1’ and normally The iiuid block passages passages |23 I I5 andvl00, and |25 communicate with grooves ||1 and |I1’ and chambers |15 and |11, respectively, of the valve motor. „ Passages |39 and |43, Fig. 6,) of the plug I5 register with the annular groove |33 of rotor I1 and passage |31 joins this groove with the out' side of rotor I1 and is in communication with y the annular groove |35 formed in the _bearing I9. Passage |45 leading from groove |35 through the wall of` the bearing I9 terminates in a` any positionl the annular groove 13 permits iiuid 30 threaded port |41 for connection through suit to. pass through radial passage 15 in the rotor I1 able piping with ñuid supply tank 5. The grooves to an annular groove 13 also formed in the cylin drical bearing I9. When the control valve is in and thence to circumferential groove 11 _formed inthe rotor and thus circulate to radial passage 81, 81'; 89, 89'; II'I, II1’, 11 and |33 together with' passages 95, 95', |23, |25, 15 and |31 form the fluid circulating means through the rotor central longitudinal bore 8|. The longitudinal ' | 1. Grooves 13 and |35 together with passages bore 8| `is blocked at the rear of the valve by a 1I and |45 and ports 69and |41 are the iiuid screw plug 83 while the forward end of the bore circulating means through the outer bearing I9. leads to radial passage 85 (Fig. 3) which is nor . The operating motor 9 is of the double act mally blocked by land 9|, which is formed on the ing type and consists of an outer _casing |59 rotor I1 between the upper ends of the semi 40 which houses reciprocating piston- I6I fastened circumferential' grooves 81Í and 81'. The lower to oppositely extending piston rods |61 passing spaced ends of these semi-circumferential grooves 'A through the outer removable ends |69 fastened . 19 formed through the valve plug I5 leading to a are supported by land'93. 'I‘hese semi-circular ' securely to the casing |59. The piston |6| divides , grooves 81 and 81"open into radial passages 95 the _motor 9 into two chambers |63 and |65 whose and 95' leading to a second set of semi-circum 45 combined volume is equal to the combined volume À ferential grooves 89 and 89' formed on the outer of the chambers |15 and |11 yof the valve motor. periphery of the rotor I1. ¢The upper and lower These valve motor chambers |15 and |11 are ends of these grooves 89 and 89’ terminate on so constructed that when one of the chambers opposite sides of lands 9|’ and 93' respectively. is expanded or enlarged by movement of plug Ports |29 and |21 join grooves 89, and 89' re 50 I5 it causes the otherchamber to be contracted spectively with the outside of >bearing 2| and thus a similar amount.` allow for fiuid` connections to `the motor cham bers |65 and |63, respectively, by means of iiuid |65 and' |63 are similarly constructed. lines |51 and |55. rotated to allow passage. of high .pressure iiuid ' ' vOperating motor chambers » In operation the valve plug I5 is manually In addition to the bore8| the --valve plug I5 55 to one side of the motor 9 and the exhaust fluid houses longitudinal bores 99, |0I, |05 and -|||. from-the other side of the motor .piston is uti 'l' One end of the bore '99 is screwthreaded to re lized to move the rotor I1 to close olf the flow of ceive one of the holding screws vfor securing the fluid. Because' of the volumetric equality be-` operating >handle 33 to the valve plug I5 with vtween the valve motorA and the operating motor the opposite end of the bore 99 terminating in 60 and the relationship of the chambers in each of a reduced diameter bore portion |05 which in these motors it will be evident that the introduc turncommunicates with an enlarged diameter tion of ñuid into one side of the motor 9 causes bore |0I. The bore IOI is plugged at its outer the introduction of an equal amount of 'fluid into end by screw plug |03 and also houses check the valve motor to cause rotation of the rotor I1. valve |01 and its associated spring |09 which 65 By knowing the total displacement of the motor normally presses the check ball |01 into engage 9 and the amount of angular movement of both , ment with the end of reduced diameter bore por surface I| and rotor I1 as a rezult of su‘ch dis-v tion |05. This check ball |01 isset to open at a placement itis a comparatively simple matter to pressure in excess of that needed for operation calibrate the angular movement of the surface of the controls although this pressure is some- 70 II in relation to the angular movement of the what less than the accumulator pressure. rotor I1 and thus determine the marking of dial The radial` passage 91 joining bore 99 with _ring 39. . l ' the outside-of the valve plug I5 is in the ’same vDue to the construction of valve plug I5 and plane and spaceddiametrically opposite from .the rotor' I1 as shown in sections 3-3 of Figures 2 radial passage 85 communicating with bore 8|. 75 and 3, it will be appreciated that when plug I5 is 2,406,178 ` Inasmuch as the motor and system are illled with iluid, the oil exhaustedfrom left hand cham ber |55 will be" forced through conduit |51 rotated, some fixed angular amount of high pres- i sure fluid will now to one Aside of motor 9 until` the exhaust fluid from the opposite side thereof will cause rotor I1 (Fig-‘4) to move a sumcient . ' through‘port |29 and passages _39, 95, 31, 91, 99, |00, |I1 and I23.to the _left hand `rotor chamber amount to close oi! the high pressure fluid ñow. |15. ' The iluid‘thereupon rotates the »rotor I1 Since both plug I5 and rotor I1 have a common and abutment 53 to the right. The exhaust oil center of rotation it is apparent that rotating ' from right hand chamber |11 then passes back valve 'plug I5 a given angular amount will pro tothe supply pipe via passages |25, II1’, H5, duce a similar angular movement oi' rotor I1_ if passages 35 and 91 are of the same width as lands 10 III, |39, |93, |31, |35, |45 and port-|41. The ro tor I1 will thereupon turn to the right until the 9| and 93. However, since these lands -are wider 'for sealing purposes than the passages, plug I5 \ fluid passage 951s again blocked by the land 9|'. When this occurs, hydraulic fluid cannot longer - must be rotated an additional amount to provide flow to themotor and consequently movement for the necessary over travel.. This is ,compen sated for in the indicator by means of pin 4I 15 thereof is arrested. At the time passage 91 is blocked by land 93, _passage I I5 is blocked by land and slot 43 and the amount of angular movement I I9 and passage |00 by land |2I so- that all ñow ' of surface I I can .be determined directly -by means> of fluid to and from the hydraulic motor ceases of the setting of pointer" on dial ring 39 when and as the rotor I 1 is stopped the system comes to the valve plug is rotated. However, this is true only if the valve motor and operating means are 20 rest with the aileron or other control -surface depressed to 45° from its horizontal position. in synchronism and the method of obtaining this To return the control surface to its original ’ synchronized relationship will be explained in position handle 33 is moved to the left. The ini tial movement in this direction takes up the over . -|I5 are all in the same longitudinal plane and 25 -travel of valve plunger I5 and after this has oc detail hereafter. _ It will be noted that passages 85, 91, |00 and curred passage 85 is put to. communication with passage 81. ` At this point the pin 4| abuts the lands 9|, 93, I|9 and |2| are in the same plane end ofthe arcuate slot 43 in the plate 45-and thus of rotor I1 and are~ of substantially' the same the plate 45 is picked up and thereafter moves magnitude. hence any movement of the valve plug the lever~33 until the plate and -its asso I5 which will uncover one of these passages from 30 with ciated pointer indicates zero on the scale plate. its land seal will simultaneously uncover the other Fluid pressure is still available at the ends of of said passages and conversely any movement of are of substantially the same width. Similarly rotor I1 whichv causes a land to cover and seal one of these passages will cause all of them to be sealed. ‘ ` , passages 8I-85 as previously described and will ' ñow to the left hand motor chamber |55 by way -35 of passages 81, 95 and 89, port |29 and conduit Inasmuch as the flow of fluid .through the valve is simultaneously in several'directions and at sev eral levels attention is particularly directed to~ the cross-sectional views illustrated in Figs. 3, |51 thereupon .forcing motor piston IBI »toward I the right to raise the aileron'. Exhaust oil from the right hand chamber |53 is forced into the ' right'hand rotor chamber I11_by-way of line |55. |21 and'passages 89', 95', 81', 91, 99, |00, 4, 5, 6 and 7. Fig. 5 is the entrance level where 40 _port |I1’ and |25 whereupon rotor |1 and the abut the high pressure _fluid from4 the accumulator ment 53 are moved to the left. Exhaust oil from enters the valve assembly I. Fig. 3 is the valve the left'hand chamber |15 of the rotor is pushed level where the high pressure _fluid il'ow to the back to the supply tank 5 via passages |23, I I1, operating motor 9 is controlled together with II5, 'I||, |39, |33, |31 and |35 to port |41. thev return i‘low vfrom the motor. Fig. 4 ls the Movement of the rotor I1 will thus continue to valve motor level where the ñow of exhaustfiuid `the left until the passages 85, 91, |00 and ||5 from motor 9 4to the valve motor is controlled and are closed or blocked ‘by lands 9|, 93, I2| and I I9 also the return flow from the valve motor back ' respectively, thus arresting any further ilow of tothe supply tank 5. Fig. 6 as supplemented by ‘~ Fig. '7 shows the return level which includes the 50 fluid. When this condition has been effected rotor I1 exit port for fluid leaving the valve and return and motor piston |6I will be in their neutral or ing. to the supply tank. mid positions whereupon if the handle 33 is now When it is desired to lower the aileron orother moved to the right until the pin 4I bisects the control surface to any desired degrees as, for ` center line of slot 43 in plate 45 the respective 55 instance 45°, the control lever 33 is rotated to positions of the valve and system will be in the right until the pointer 41 registers with the identical position to that assumed at the start 45° mark'on the scale. It will be noted that the of the control operation. This last movement pin 4| carried by the operating lever of handle to the right of lever 33 will produce no movement 33 does not connect with or pick up the plate 45 of either the piston IBI or rotor I1 _as it merely carrying the pointer 41 until the valve plug- I5 00 reestablishes the valve plunger I5 to its original fastened to the lever 33 has moved through the starting position with the passages 85 and 91 distance of the slot 43 so that the pointer does not centered on lands 9| and 93 respectively. start to register on the scale until the valve plug While this latter position of the valve plunger I5 has moved suillciently to bring the fluid pas I5 contributes nothing. to the operation or move - sage 85 into communication with passage 81' ment of the aileron while the'alrcraft is in flight, thereby taking up the lap or overtravel. With it d_oes provide a positivemeans _of sealing the the pointer 41 and valve plug I5 rotated to coin hydraulic fluid in the system when theaircraft cide with the 45° scale marking the high pres is on- the ground and the pump 1 >is not in oper sure hydraulic fluid will'then flow from the ation. The overtravel or lap provided by lands accumulator 3 to the passage 85 as above' de 9|, 93, |I9 and also |2I preventsflutter of the scribed and continue to the motor 9 by way of -Ipassages 81', 95’, 89', port |21 and conduit |55 to the right hand chamber |53 of the‘motor where the fluid will force the double acting piston |5I 75 to the left thus lowering the surface II. aileron when the ship is in flight by allowing overtravel of the rotor I1 when coming up to the stop'position. The lands being wider than the diameter of the passages they block, prevents the 2,406,173 slight overtravel of the rotor I1 from producing a reversal of flow of the hydraulic liquid and thus the flutter condition caused by such reversal is eliminated and a dangerous and undesirable condition avoided. . l - To raise' the aileron above its horizontal posi tion the pointer plate 45 and pointer 41 are moved to the left through the medium of the handle 33 to the desired degree of elevation a's indicated on the scale 39. . High pressure fluid thereupon part 55 before the piston 6I reaches the end-of the motor cylinder. With the pointer 41 set at` >the timing mark rotor I 1 will come to rest againstvr part 55- without closing 0E passages 85,` 91, |00' or I|5 and fluid will continue to flow to the ' chamber |63 and, also, to chamber |15. However, if the‘chamber |15 isfilled with fluid the pres sure vthereof in passage 99 will be sufllcient to lift the check ball |01 from its seat and the fluid 10 released will flow back to the supply tank 5 by fiows from passage 85 through passages 81, 95, and 89, port |29 and conduit |51 to the left hand motor chamber |65 and forces piston |6| to the right thus elevating the aileron. Exhaust oil from chamber |63 is moved by the operation of the piston through line |55, port |21, passages way of passages |05, IOI, |43, |33, |31, |35, |45 and port I 41 until the motor piston I6| reaches thel end of. its stroke, -thus cutting oif the supply of fluid goingv to passage 99. Since both motor piston I6| and rotor I1 are now at their extreme positions they are again in time and any move- « hand rotor chamber |11 whereby the rotor I1 mentofpiston |6| will produce a correspondingmovement lof rotor I1 if the valve plunger I5 is and its abutment 53 are rotated to the left. Ex rotated to permit 'such movement. 89', 95', 812.91, 99, |00, ||1' and |25 to right haust ñuidfrom chamber |15 is forced back into the supply tank 5 by way of passages |23, ||1,` ||5, III, |39, |33, |31, |35 and |45 to port |41. _' By providing .air bleeder valves or cocks I8| r and |83, in motor chambers |65 and |63, the control valve and ñuid ïmotor may be filled with oil regardless of the relative positions of the The motion of the rotor I1 is arrested when it piston"î.„|6|- and rotor I1. To initially illl the catches up with valve plunger I5 and lands 3|, 93, ||9 and |2| block the ñow of oil from pas 25 valve and motor, or to add additional fluid there» sages 85, 91, ||5 and- |00 respectively. L to, all connections to the accumulator, `tank and motor are made and the system is filled by alter Since the fluid'circuit just described is iden-4 nately moving lever 33 to the right and left tim tical to the circuit necessary to raise thé aileron ing positions several strokes. If it is assumed or other control surface from its lower or de pressed position back to its horizontal or neu 30 that the rotor abutment 53 is to the left of its mid position when ñlling operations are started, tral position, it is evident that to raise the aileron, then, when lever 33 is moved to the left until it the handle 33 must be moved to the left and to reaches the left timing position, high pressure lower 'the handle must'be moved to .the right. fluid will flow from the accumulator to the mo The position that the aileron will assume4 when it comes to rest can always be accurately deter 35 tor cylinder as has already been described. By mined by observation of the position of the - keeping the air bleeder 'IBI of the chamber |65 pointer 41 registering on 'the scal’e plate 39. open until a solid stream of iluid appears all ' Before taking ofi’ for a flight or putting the ` _ system into voperation~ it is. essential that the air between the accumulator and the left-hand ' chamber |65 will be exhausted and' replaced with operator be sure that the control apparatus is 40 fluid. Piston |6| will also be moved to its ex treme right position forcing air from right-hand in time as occasionally the motor piston |6| is not precisely synchronized with the rotor I1. ' chamber |63 to the right-hand valve chamber |11. Inasmuch as air is compressible, the abut-v l, To ascertain if the motor and control» valve are ment 53 may or may not be moved to its extreme in proper timed relation the operating lever 33 ` should always be moved to both the right and 45 left stop position as a result of the air being left extreme positions. If it is found that the piston I6I and the rotor I1 are not in timed rela tion, the movement of the lever to the extreme right and leftpositions two or three times will retime or synchronize the apparatus in the fol 50 forced into chamber |11. However, any move ment of the-'abutment 53 to the left' will force some ofthe air in the chamber |15 and the con necting ñuid‘passages back into the supply tank. When lever 33 is now moved to the right timing Assuming that the piston '|6I position, fluid will flow to the right-hand motox` has moved to the right without a corresponding movement; of the rotor I1, then, if lever 33 is pushed al1 the way over toward the left until the chamber |63 in the manner previously described - and, by opening the bleeder |83, all air between the right side of the piston |63 and the accumu i lowing manner. pointer 41 registers with the “time” position on 55 lator 3 will be exhausted and replaced by fluid. Piston |6|4 is, consequently, forced to the the scale 39, hydraulic ñuid will iiow from the` accumulator 3 to the left-hand chamber |65,- left. until its stop position is reached and the i forcing piston I6| to theright, and moving fluid fluid in chamber |65 and the lines and passages 1 from chamber |65 into valve chamber |11, while ‘ l , . ' to chamber |15 is forced into the chamber ñll the iiuid from chamber|15 is forced back to the 60 ing it with -a measure of fluid and air which supply tank 5. Since motor piston I6| is out of tends to move vtofth‘e lright but, due to the com pressibility of the air, the rotor I1 may or may time. but, being ahead of the rotor I1, when mov not reach vits right stop position. Whatever ing toward the right, the piston will reach the ¿ end of its travel without having displaced suiil movement takes place forces some of the air out ‘ cient fluid to push rotor abutment 53 to its left 65 of the chamber |15 through the connecting hand stop 59 on .part 55 and, thus, the rotor I1 ' passages back to the supply tank and it will be will still be out of time with the piston I6I.- If , the lever 33 is now pulled over toward the right understood that after this first right and left cycle is completed the system is full of fluid ex >until the pointer 41 lines` up with the right cept for the valve chambers |11 and |15 and „ l timing position on the scale, fluid will 'then iiow 70 connecting passages to the supply tank as ~they i from the accumulator 3 `to right-hand motor ` chamber |63, forcing piston I6| to the left and _ ï moving .the exhausted fluid to left-hand valve i chamber |15. _Rotor I1 now leads the piston |66 now contain a mixture of ñuid and air. 'I'he second cycle of vvleft and ri’ght movement of the lever 33 will force the air and :duid mixture out of the chambers |11 and |15, together with their ‘ andthe abutment 63 will come to its stop 6| on 75 connecting passages, back to the tank and the 2,408,173 9 , ' f5 A servo-motor control~k system for- use Ã- with ’ `a source o! liquid >under pressure including in air and -:lillid mixture lwill be replaced by fluid alone. A third cycle of operation to the right ~ combination; -a double-acting" servo-motor lhav ing two alternatively filled and emptied cham and left will serve to put the various parts of the unit in timed relation ii they are not already bers, a control valve having a'iirst element mov able to open position to selectively connect one of said chambers to said source, a` second ele-. position, when lever 33 is moved to the left f ment cooperating with the ilrstrto provide follow .timing position, high pressure iluid from the ac up to close saidcon'nection, a double-acting valve .'cumulator will illl chamber liiilrst and >repeat the previously described conditions. Should the 10 lmotor connected to move said second element, said .valve motor having two chambers each 'at ~ ilrst movement oi the leverV 33 be to the right least as large in all corresponding displacements instead of to the left the system would be again _in this condition. Ii we now assume that abut » ment I3 of the rotor is to the right oi its mid "as the corresponding chamber o! the servo-motor and adapted to be alternatively illled and scribed except that chamber IGI would be ñrst filled due to the reversed flow o! fluid from pas 15 emptied, means including a portion of said valve _for connecting the discharging chamber of said , sage 85. Similarly, the timing operation may servo-motor to that chamber ot the valve motor be started >to the right position instead of the . which moves the follow-up element toward valve .left position and the desired results accom 'closing position, and means in said valve to con plished. _ ' iilled with iluid in the manner previously de ' 20Jtrol the discharge from the other chamber of ~ l the valve‘motor while preventing discharge from _ 1. In a hydraulic control system for use with a the _ñlling valve-motor chamber;A source of high pressure liquid, in combination, a 5. A servo-motor control system for use with double-acting servo-motor having'similarV liquid a source of liquid under pressure including in displacement at the two ends thereof, a control I claim: valve element movable to selectively deliver high 25 combination, a servo-motor having a piston c pressure liquid directly to either end of the mo separating oppositely expandible chambers , a livery whereby said follow-up is instantaneous. follow-up element toward valve closing position multiple control valve including a ilrst element tor, ‘a double acting valve. motor having two movable to selectively connect one of said cham chambers, a second valve element associated for bers to said source, a second element cooperat movement by said valvemotor and providing a follow-upl for- the ilrst valve element, means to 30 ing with _the ñrst to provide follow-up, a valve motor connected to move said second'element deliver all of the liquid discharged from the in and having a piston separating oppositely ex active end of the servo-motorto that chamber Y pandible chambers, means including a portion of the valve motor which will cause movement of said valve for simultaneously connecting the of the follow-up valve element to close oi! flow to the servo-motor, and means to maintain said 35 discharging chamber oi' said servo-motor to that chamber o1' the valve motor which moves the last mentioned chamber closed during said-de 2. A servo-motor'control system for use with a source oi liquid under pressure including in combination, a double-acting servo-motor hav ing two alternatively filled and emptied cham and means to cause said follow-up to act in uni son with the movement of the servo-piston. ¿o 6. A servo-motor control system- for use with _a source of liquid under pressure including in combination, a servo-motor having a piston bers of like iluid capacity, a control valve hav kseparating »oppositely expandible chambers, a ing a i‘lrst element movable to open position to multiple control valve including a ñrst element selectively connect one of said chambers to said source, a Asecond element cooperating with the 45 movable to selectively connect one of said cham bers to said source, a second element cooperat ñrst to provide follow-up to close said connec ing with the iirst to provide' follow-up, a valve tion, a double acting. valve motor connected to motor connected-tomovesaid second element move said second element, said valve motor hav and having a piston-"separating oppositely ex- ' ing two chambers adapted to be alternatively -pandible chambers, means inclugling a portion of filledV _and emptied and means including said - said valve for> simultaneously connecting that valve for connecting the discharging chamber .chamber oi the valve "motor which moves the of said servo-motor to the chamber _of the valve motor which moves the follow-up element toward _ _' ' valve closing'position, said‘means preventing dis charge from the valve-motor chamber while it is filling to provide instantaneous ,follow-up. 4follow-up element toward valve closing position to' receive and hold the wholeëfdischarge from . the inactive chamber of the ‘servo-"motor 'to pro vide synchronous follow-up. 3. A servo-motor control system for use with n ' a source of liquid under pressure including in combination, a double-acting servo-motorhav ing two alternatively filled and emptied cham 60 bers, a control valve having a first element movable to open position to selectively connect one of said chambers to said source, a second ‘ element. cooperating with the first to provide follow-up to close said connection, l adouble acting valve motor connected to move said sec ond element, said valve motor having two cham bers each at least as large in all corresponding ' . 7. A servo-motor control _system for use with a‘ source of liquid under pressure including in combination, a servo-motor having a piston sep arating alternatively expandiblèívchambers, a control valve including a first element movable` _ optionally through and beyond- `the distance necessary to connect either of said? chambers to ~ fsaid source, a second element cooperating with the ilrst to move through the selected distancel ' to provide follow-up to close said connection, a valve motor connected to move said second ele ment and having a'piston separating alterna displacements as the corresponding chamber of expandible chambers each at least of the the servo-motor Iand adapted only to be alter-‘ 70- tively same maximum volume as the ’corresponding natively ñlled and emptied and means including motor chamber; and means for connecting >a. portion of said valve for connecting the dis that chamber of .the valve motor which moves charging chamber- of >said servo-motor _to that the follow-up element toward valve closing posi chamber of the valve tmotor which moves the follow-up element ltoward valve closing position. 75 tion to receive and hold all of the liquid dis 2,406,173 , 11 charged from the inactive chamber of the~ servo motor. 8. A servo-motor control system for use with a source of liquid underv pressure including in combination, a servo-motor having a- piston vane on said sleeve, said valve- motor having two chambers between said -vane >and abutments adapted tobe alternatively iilled and emptied, means including ports forming part of said valve > for connecting the discharging chamber of said separating alternatively expandible chambers, a servo-motor to the chamber of the valve motor which' moves the follow-upelement toward valve control valve including a ñrst element movable optionally. through and beyond the distance closing position,»means to limit the movement/of necessary to connect either of said chambers to the valve motor in each direction and -a relief said source, a second element cooperating with .valve so„in’corporated in the system'as to vent the emptying chamber Vof the servo-motor if the valve motor reaches its limit of movement ñrst the first to movethrough the selected distance to provide follow-up to close said connection, a valve motor connected to move said second ele ment and having a piston separating alterna tively expandible chambers each at least' of the 15 as a result of being not synchronized with the servo-motor, whereby-synchronism is restored. . 1l. The system of claim 10 wherein the relief same maximum vvolume as the corresponding valve is a single valve in the central valve ele motor chamber, means forconnectlng the dis ment so arranged as` to always subject'to the charging chamber of said servo-motorA to that pressure tending to move the valve-motor. ‘ chamber of the valve motor which moves the l2. Al servo-motor control system for use with follow-up. elementv toward valve closing posi 20 a. source of liquid under pressure and a‘supply i tion each'of saidy valve-motor chambers having tank including in combination, a double act 1 but a single iluid passage, and means associated ing' servo-motor having two alternatively filled with the ñrst valve element to designate the and emptied chambers, a control assembly in î extent of movement of the servo-motor piston cluding avalve having a central cylindrical ele fment rotatable from normally closed to open po element. sition to selectively» connect one of said chambers 9. A servo-motor' control system for use `with to said source, a second valve element compri/s a source of liquid under pressure including in ing a- sleeve surrounding the ñrst element and cooperating with the same to provide follow-up combination,.a double acting servo-motor hav ing a. piston' separating two alternatively filled 30 to resume normal closed position, a double act and emptied chambers, a control assembly in ing valve motor comprising an arcuate housing cluding a valve having a central cylindrical ele- ‘ having abutments and a vane on said sleeve, said ‘ resulting from any particular setting of said ` ` " _ ‘ ` i ment manually- rotatable to open position to valve motorl having two chambers between said selectively connect one of said chambers to said vane and abutments‘adapted to be> alternatively ï source, a second valve element comprising a 35 i-llled and emptied, means including- ports form sleeve surrounding the ñrst element and co operating with the same to provide follow-up to ` ing part of said valve for connecting the dis charging chamber of said servo-motor to the close said connection, adouble acting valve mo chamber of the -valve motor which moves the l tor comprising a housing having abutments and follow-up element'towa?d valve closing position a vane on said sleeve, said valve motor having 40 and to connect the discharging ~chamber of the ï two chambers between said vane and abutments ` adapted to be alternatively vfilled and emptied "and means including ports forming part of said valve motor to said tank when the ñrst valve element is moved from normal position. 13. Valve means for use with a servo-motor i valve for connecting the discharging chamber control system including in combination a mul of said servo-motor to the chamber of the valve 45 tiple control valve having a manually movable ï motor which moves the follow-up element towar element assembly and a ñxed element, passages in said element and assembly adapted for align ment to- conduct fluid, said members when in a source of liquid under pressure including in “oiï” position having lap to prevent leakage, a combination, a double acting servo-motor hav 50 scale part, a pointer part tocoopera-te with said ing a piston separating two alternatively ñlled scale to indicate the actual amount of relative and emptied chambers, a control assembly in movement of -said parts after said lap has been 1 valve closing position. v i » 10. _A servo-motor control system for use with. l 1 f i cluding a valve having a central cylindrical ele- . ‘ passed, means securing one of said parts to a ment manually rotatable> to open position to stationary portion of the` valve, and means pro selectively connect» one of said chambers to said 55 viding a lost motion connection for the other source, a second valve element comprising a part to said movable valve element, the amount sleeve surrounding the first element and cooper- ` of lost motion provided being just su?licient to ating with the same to provide follow-up to close compensate _ for said lap. `said connection, 4a double acting valve motor ' \ comprising a housing'lhavilng abutments and a 60 WmJAM T. STEPHENS.