US2344308A - Governor - Google Patents

Description

, A. KALIN GOVERNOR March 14, 1944.

Filed April 1, 1942 UEL ON FUEL OFF N M u w RK m PM R N 0 2 n m UA A Patented Mar. 14, 1944 UNITED STATES PATENT OFFICE 1 2,344,308 f I GOVERNOR Alb'er'tiKalin, Cleveland, Ohio Application April 1, 1942, Serial No. 437,122

15 Claims.

This invention relates to improvements hy draulic relay governors of the type-shown forexample in my Patent 2,219,229, issued October 22, 1940, and in my application Serial No. 385,228 of March 26, 1941, now Patent No. 2,324,514, issued July 20, 1943; Without intention to limit the invention to governors of any particular class, the principles of the present invention ;will be discussed herein only as applied to-speed'goveming. The principal objects areas follows:

One object is to provide an improved subservient control mechanism for'a governor oper- A further object is to provide an improved automatically operating emergency control mechanism for speed governors for prime movers,

which control mechanism is responsive to-special speed and low relationships-for example low speed and abnormally heavy load-for limiting power input to the prime mover under 'suchcondition (brake mean effective pressure control).

Another object is to provide an extremely sensitive speed responsive subservient control mechanism for a main speed responsive mechanism of agovernor.

' Another object is to provide animproved speed responsive, hydraulically operating subservient control mechanism for a hydraulic relay: gover nor wherein adjustment for :load limit and actu-' 'ating speed point canbe easily-efiected and maintained.

Other objects include the provision of an improved brake mean effective pressure control, hand shutdown and lubrication oil failure shutdown mechanism, in-which the actuating. parts are coaxially arranged but independently operable.

Still another, object is to provide a hydraulically operable shutdown orslow down system 'for a hydraulic relay speed governor wherein all the essential parts can jefiectively be mounted on a mitary servo-motorblock or body.

Referring to the accompanyingdrawin g Fig. l is a general assembly schematic .view of a speed governor incorporating the invention inoneform; V

Fig. 21s a similar view, showing part, only of the governor, with the principal valve elements hereof ina differentrelationship. y

Referring to the main governor mechanismshown at the left in Fig. 1, parts indicated generally by letters'A'represents a positive displacement hydraulic pump, having a reversiblevalve system, adapted to draw hydrauliciluid from a sump S and deliver it to an accumulator B having a spring loaded'plunger c 'and'dischargevent D which cooperate to maintain pressure in a, de-

livery duct E at substantially constantlivalue.

The pump A is suitably connectedwiththei-en 'g'ine or other machine to 'begoverried yas isalso a speed responsive ballhe'ad Lo'f thegovernor.

' Fluid from the accumulatorsissupplied:continuously during operation of the governor through the duct E to a relatively small race F of a double acting regulating servo-motor piston G, tending to move said piston in a} direction to decrease power input to the engine (downward v movement as illustrated). Fluid fro m'the'du'ctE is controlled at a' port E of -'saiddiict by a lower "or balanced position; and when the piston is lowered from that position pressure fluid flows to said larger face of the piston G to cause powerinput-increasing (upward) movement of said pi'ston. Upward movement of the pilot valve plunger, from normal position; causes 'an upper land portion H! o'f the plungerto opena-portKjeadingto sump 3 thereby dumping-fluid frombelow the servo-motor piston and causingpower-i putdecreasing movement of said piston reason of the constant pressure maintained'at the top fafce Fof the piston. ,7 f;

The pilot valve plunger H ismoved axiallyin opposite directions as "a result of the difference between "centrifugal force on 'flyballsIj-Iif of the ballhead and fan 'oppos'ing' fforce exerted: by an adjustable speeder 'sp'rinfg M, so thatan increase in speed on part of the engine (resulting from decrease in load) raises the pilotvalve plunger and a decreasein speed tresuit ngfrom-increase in load) lowers saidplungerlj nn adjustable a compensation fluid duct 0 on a receiving prif mary compensation piston element P of the pilot valve plunger H, said piston P slidingly sealing an end portion of the duct 0 opposite the pump.

A coil spring Q corotatively connects the receiving compensation piston P and the pilot valve plunger (opposite ends of spring respectively pilot valve plunger during loadchange. Secondany compensation is secured'by a restricted adjustable leak aperture (needle valve R) communicating the interior of the compensation fluid duct 0 with the governor sump and which acts to dissipate the force stored in the'spring Q by each movement of the pumpplunger N incident to movement of. the servo-motor piston G.

In my Patent No."2,324,514 there is shown and claimed 'a' subservient control system including means for diverting high pressure hydraulic fluid from'a part of theh'ydraulic governor relay to a hydraulic compensation system such as above described,- wherebylas in certain emergencies) temporarily to take control of the engine away from the main speed weighing machanism (the ball head L, etc.) by operating themain pilot valve independently of the speed weighing mechanism. Said arrangement operates very effectively in connection with .ahydraulically double acting regulating servo-motor, that is: one which isfiuid pressure operated both in fuel on and "fuel off" direction. Such a servo-motor in a hydraulic relay governor cannot be caused to move in the"-fuel ofi direction simply by venting hydraulic fluid from the appropriate end of the regulating servo-motor cylinder because the resultant decreasein speed-of'the flyball head would immediately cause hydraulic fluid to be ventedalso from the opposite end of the servo-motor cylinder and cause. the fuel off" movement to .;cease. No. 2,324,514) for certain practical uses required However, said arrangement (per Patent shutting off of the secondary compensation leakofi from thatpart of the hydraulic compensation system into which the high pressure fluid was diverted -as-' for shutdown vpurposesthus sometimes complicating the construction and requiring disproportionate expense. The present arrangement, inter alia,simplifies the valving equipment necessary for making a positively acting hydraulic subservient control, such as that of said application SerialNo. 385,228, when applied to governors having hydraulically double acting speed regulating I servo-motors. The arrangementhas-other important. advantages which will be pointed out'later herein.

Rete'rrin'g furtherto-Figl, portions orthe 'regulation fluid duct I which conveys hydraulic fluid to and from the larger pressure space of the regulating servo-motor are formed or located in a unitary servo-motor block I attached rigidly to the power case 2 of the governor as along a smooth face indicated by the line 3. Said block is separable from the power case, as usual. A horizontal portion 4 of the duct I intercepts a vertical bore 5 leading downwardly from the top face of the servo-motor block. The lower end of the bore 5 intercepts a generally closed, space 6 of the servo-motor-block above and partially surrounding the smaller diameter trunk portion 1 0f the power piston G, which space 6 is suitably vented to sump. Intermediately of the ends of 15' the vertical bore 5 a horizontal portion 9 of the regulating fluid duct I extends from said vertical bore 5 and is connected with the relatively larger cylinder portion of the servo-motor as through a fixed tube In slidable in an axial bore of the piston G, which axial bore communicates with a lateral passage ll in -the piston leading to a point below the j'face'J of the piston. Mounted in the vertical bore 5 fonaxial adjustment therein is a valve sleeve I5-having a cylindrical bore I6 extending therethrough and necked portions I1 and I8 forming separate cylindrical lands l9, 2|] and 2| on the sleeve fitting the bore 5. The necked portion I! has lateral ports 4' communicating the portion 4 of the duct I with'the interior of the valve sleeve. The necked portion I8 has ports 9' communicating the portion 9 of the duct I mm the interior of the valve sleeve. Slidable in theaxial bore- I6 of the valve sleeve I5 is a valveplunger 25"having a stem-23 and cylindrical lands'26 and 21 fitting'thebore l6 and separated by'a neck 28'. The valve plunger lands 26 andZTnormally are spaced well above and below theports 4 and 9' respectivelyof the valve sleeve forenabling free movement of fluid in the duct trol of the regulating servo-motor at all times.

Below the lowermost -land- (2|) of the valve sleeve l5 isan additional set'of lateral ports 24 which lead from the axial bore of the sleeve to sump space aswill be obvious from the drawing. The operating stem 23 of the valve plunger 25 extends'upwardly out of the sleeve'l5 forenabling-the subservient control operations, men- -tinned earlier, by sliding of the valve plunger into d-iiferent positions in respect to the ports of 'thej'sleeve' IS. The valve plunger 25 is arranged to be adjusted automatically (for one operation hereof) by a low speed responsive ballhead mechanism indicated generally at 30, which mechanism will be described in detail presently. For operation of the subservient control valve "mechanism automatically in accordance with predeterminab le load and speed relationships "(B. E. P: control; outlined above), the valve sleeve I5 is arranged to be shifted by the servomotor piston 'G from'an initial position, in which the low speed responsive mechanism of the valve "plunger 25'nevertakes'contro1 away from the main pilot valve plunger, gradually'into raised j positions in which said mechanism of the valve plunger 25 can take control; but only in a manher to decrease'or cutoff fuel supply to the en-,

'A suitable spring 32 (shown at'th'e upper end of the valve sleeve urges the valve sleeve downwardly; and a'vertically adjustable abutment 33,

shown as screw threaded to the lower end of the valve sleeve l5, may be used to determine the represents a screw (or toothed rack) meshing with vertical or nearly vertical flute teeth 35 on the abutment 33 by which the abutment may be turned to adjust it with reference to the valve sleeve. The teeth 35 are long enough to enable the necessary vertical movement of the valve sleeve without separation from the adjusting member 34.

For brake mean effective pressure control of internal combustion (e. g., Diesel) engines equipped with the present governor mechanism the ballhead 30 is mounted, as on the servo-motor block l,in position to control the valve plunger cooperatively with the movements of the valve sleeve [5 by the servo-motor. As shown, the ballhead comprises a tubular body mounted for rotation, as in antifriction bearing assemblies 4| and 42, on a bracket 43 supported by the servo-motor block. The ballhead body 40 has a driving pinion 44 keyed thereto, between thebearings; and the pinion is driven from a gear 45 on the main ballhead L, as through an idler gear '45 suitably supported in fixed posi tion on some rigid part of the governor and in constant mesh with the gear '45'and driving pinion 44.

Flyballs 41 pivoted to the ballhead 30 have arms 48 bearing upwardly against a thrust plate (disc) 49 on the stem 23 of the valve plunger 25; and a coil spring 50 bears downwardly on the thrust plate and tends to hold the flyballs in their inward position (as shown in broken lines). The upper part of the 'b'allheadis in the form of a rigid sleeve 40' encasing the spring 50 and having vertical slots 5| through which the ball arms,

48 extend. The slots 5| of the sleeve 40' limit the outward movement of the flyballs,.and the upper end of the sleeve is adapted to carry a tubular threaded adjusting plug 53 and locknut 54 by which the compression of the'spring 50 may bev easily adjusted and fixed at the necessary value.

Because it is frequently desirable to use the valve mechanism (valve plunger 25, etc.) 'for emergency shutdown purposes the stem 23 of the valve plunger 25 is so :made at its upper end that it can readily be depressed by a force exerted otherwise than by the coil spring 50, while nevertheless enabled to rotate continuously within the coacting valve sleeve 1 5 whereby to prevent sticking and lack of sensitivity in responding to changes in speed imparted to the flyballs 41. As shown, the stem 23 of the valve plunger has an enlarged flange or shoulder element 55 fixed thereto which is held iii-contact with the underside of the thrust plate 49 by the spring 52 which is contained within the ballhead body '40. If the thrust plate 49 were to be fastened rigidly to the stem of .the valve plunger (as it would be in a construction wherein no supplementahe. g., hand, shutdown is required) then the spring 52 and shoulderelement 55 would be omitted. ".lhe upper reduced end 5! of the valve plunger stem (part of shoulder element 55 as shown) slides in a central hole in the thrust plate 49fand'75 a provision for making certain that the rotation of thethrust plate will also turn the valve plunger may comprise a splined connection between the reduced stem" portion 5! and the thrust plate 49 as conventionally shown. The thrust plate is gripped at all times between the ball arms 48 and spring 50 and thereby caused to turn continually during operation of the governor, thereby continually spinning the valve plunger 25.

Lubrication oil failure shutdown One emergency shutdown means in addition to the B. M. E. F; control ballhead mechanism 30 comprises, as shown; a pressure responsive motor in the form of a Sylphon bellows 60 suitably mounted in fixed position above the ballhead 3ll. The bellows is double walled, as shown, I

and one end of it carries a rigid thrust plate 6| adapted to operate a rod 62 extending loosely through the tubular adjusting plug 53 of the ballhead 30 to a point adjacent the upper end of the stem part 51 of the valve plunger 25. The

rod 62 may have a rounded end which simply rests on th stem part 5'! (also shown as rounded) for vertical support. If the bellows chamber is connected to an appropriate part of a forced feed lubrication system of the governed engine, and the pressure force in said system normally keeps the bellows distended beyond its normal length, then failure of lubrication oil pressure will cause the rod 62 to be lowered, depressing the valve plunger 25 a suflicient distance to cause shutting down of the engine in that event. An auxiliary collapsing spring 64 for the bellows 60 is shown above said bellows reacting, for example, against the usual cover plate of the governor speeder case (not shown).

Emergency hand shutdown Another emergency shutdown means shown in Fig. 1 comprises an additional rod 6'! having a lower end portion smaller than the rod 62 extending loosely through a central aperture 68 in the thrust plate 6! of the bellows and poised over the upper enclcf the bellows-actuated rod 62, so that the rod62 and the valve plunger 25 may be operatecl downwardly at any time either by the bellows 69 or the rod 61. An operating button for the rod 61 is shown at 69. The button would ordinarily lie outside the top cover 10 of the governor so as always'to be accessible for emergency shutdown of the engine by the attendant. ultimate operation of the various mechanisms 39, 6t, 61, etc.) through actuation of the valve plunger 25 will be reviewed later herein.

full normal load; the flyballs 4'! of the subservient controlmechanism will then be in the position illustrated in full lines and the regulating fluid duct I will remain open from end to end. If the load on the engine is increased, causing the main ballhead L to decelerate, the main fiyball mechanism will then cause the servo-motor piston to move upwardly or in the fuel on direction to enable the original speed of the engine to become reestablished notwithstanding the added load. But if the added load is of such magnitude that the engine speed drops until the centrifugal force on the subservient control ilyballs 4'! is insuflicient to maintain the valve plunger 25 in The :ra'ise'd position then the upward regulation stroke -of the piston will be limited, by operation of the -;valve plunger 25 and sleeve l5, to less than maximum fuel on travel, so long as excessive load continues to be imposed. Such operation of the subservient control mechanism can be made to limit the brake mean effective pressure in the engine cylinders to a safe value notwitstanding the fact that the normal operation of the main flyball mechanism L,.through the pilot valve H,-:

always operates to cause movement of the servomotor piston G in the fuel on direction consequent upon deceleration of the engine.

Fig. 2 shows the relative position of the valve sleeve l5, valv'e plunger 25 and associated ports -of the servo-motor block when the servo-motor .piston G commences to lift the valve sleeve at a time when, because of low speed, the flyballs 4? swing inwardly and permit the spring 50 to lower the valve plunger 25 sufficiently to cut off.

the supply of regulating fluid to the servo-motor.

Fig. 2 also shows the venting of regulating fluid ward stroke of the piston-see Fig. 2) then lowering of the valve plunger 25 by the slowly turningfiyballs 4'! will first seal the ports 4' (through operation of the plunger land 26) and then dump the operating fluid trapped in the right hand portion of the duct 1' to sump through the ports 24. Sealing of the ports 4' gradually stops the feeding of regulating fluid to the lower part of the servo-motor cylinder so that'the main flyball head is prevented from causing further feeding of fuel to the engine; and unsealing of the ports 24 of the valve sleeve l at the upper edge of the land 21 of the valve plunger dumps the regulating fluid from below the piston G so that fluid;

from the duct E can then act against the upper face F of the piston G and commence to cause fuel off movement of said piston. Fluid will j be fed to the upper side of the piston G notwithstanding the lowering of the main governor pilot valve H (as speed drops) because the supply portion of the regulation fluid duct I will be blocked at the closed ports 4' as shown by Fig. 2.

The fuel off" movement of the piston G will continue only until either the lowering of the.

valve sleeve I5 by the piston G or raising of the valve plunger 25 by the flyballs 41 unseals the ports 4 of the valve sleeve. Thus the feeding of fuel will be maintained at a safe maximum as determined by the setting of the abutment 33 (or the position of the lower end of the sleeve IS in' case there is no provision for adjustment) until either the excessive load is dissipated or normal speed resumed notwithstanding the abnormal load.

If the excessive load is dropped suddenly, the engine is nevertheless prevented from racing because, as soon as the engine speed increases toward normal, the flyballs 4'! reposition the valve plunger 25 upwardly as from the position shown I in Fig. 2 into a position closing the regulation fluid discharge ports 24 and opening the regulation fluid supply inlet ports 4', whereupon the main ballhead mechanism L, through the pilot valve plunger H and the speed stabilizing complace.- I

-movement of the power pensation mechanism (N; P; etc;) immediately assumes control of the servo-motor piston G both in fuel on and fuel off! direction to regulate the engine. 7 I I 5 I If for any reason the flyballs 41 do not become eifective to raise the valve plunger 25 to a point such as will unseal the ports 4 (although closing the discharge ports 24 as in a neutral relative position of the valve plunger 25 andsleeve l5) in response to restoration of the enginespeed upwardly toward normal, the fluid from below the piston G can nevertheless be vented as through a spring-closed check valve 12 located opposite the regulation fluid duct portion 9 and communicating the latter (for venting travel only of the fluid) with a portion of the duct I lying between the ports 4' and the pilot valve H. Thus at no time I can fluid be trapped below the piston G- to prevent the main'ballhead mechanism from moving said piston in the fuel 01f direction.

In-regard to the auxiliary shutdown mechanisms (Gil-62 and 6169) it may be noted-that those mechanisms can assume complete shutdown control of the engine at all times simply by enabling those mechanisms to depress the valve plunger 25 until the ports 4' are sealed by the valve plunger land 26 and .the ports v24 are unsealed by movement of the upper edge of the plunger land 21 downwardly beyond the uppermost limits of said ports 24. Also it will be observed that the force necessary to be applied to the valve plunger 25 (as bythe Sylphon 60) is wholly independent of any opposing action of the subservient control flyballs 4'! (tending, particularly at high speed, to oppose downward movement of the valve plunger 25) because the valve plunger stem portion 51 can simply slide downwardly in the flyball thrust plate 49 as the shutdown actions of the Sylphon or hand operable rod .61 take Load limit 'Without substantial modification, the mechanism above described can be usedto provide what is usually termed load limit governor operation"that is' to say limiting of the extent of movement of the servo-motorin"fuel on direction-independently of speed. For illustration, there is shown an arm 15 adjustable as by turning a mounting shaft 16 for the arm to cause depression of the valve plunger 25 mesa position in which the land 26 partly closes the ports 4' at normal speed. Then (as determined by the adjustment of the abutment 33 or its equivalent) the power piston'G in raising the valve sleeve l5 near the end of the fuel on stroke will complete closing of the ports 4' and stop said fuel on piston; 'Thearm "I5 may have paired arm elements arranged to bear on a shoulder 11 of the rod 62 whenthe arm 15 is turned a predeterminable amount counterclockwise from the position in which shown. The operation of limiting the-fuel on stroke of the servo-motor by means of the device 15-11 does not interfere withoperation of the lube-oil failure shutdown mechanism 60-62 or of the hand shutdown rod 61; but said limiting operation could renderthe inward movement of the flyballs 41 inconsequential if the shoulder 11 were to be depressed by the arm 15 a suflicient amount so that said inward movement of the flyballs 41 would not cause abutment of the thrust plate 49 v with the shoulder 55 of the valve stem as the flyballs 41 swing inwardly to their innermost position. I

area -e .Il a m 'J 1, In a, hydraulic, relay governor,' comprising a pilot valve and a regulating" servomotor con trolled by said valve and having differential pres-. sure areas so arranged that, pressure fluid maintained continuously at one pressure area causes regulating movement of ct he. servo-motor in one direction upon pilot-valve-controlled relief of pressure at an opposed relatively larger pressure area of the servo-motor and pressure fluid applied at the effectively larger pressure area under control of the pilot valve causes regulating movement in an opposite direction, the combination therewith of a three port valve operatively interposed between the pilot valve, and servo-motor and having plug means operable first to. close a port leading to the pilot valve whereby to block fluid communication between the pilot valve and said eifectively larger pressure'area and then to open another port while tl1e first port remains closed and a third port maintains communication between said three port valve and the effectively larger pressure area, whereby to :vent pressure fluid from adjacentsaid latter area, and means for actuating said three port valves,

2. In a hydraulic relay governor, a regulating servo-motor and a pilot valve arranged to control a supply inlet and Venting outlet duct for pressure fluid communicating; with a pressure chamber of the servo-motor, whereby to condition the servo-motor for operation in opposite directions, valve means associated with said duct between the pilot valve and pressure chamber, said valve means having a, plug element vand cooperating port arranged to block the portion of the duct leading from the pilot valve to said valve means and another plug element'andcooperating port arranged subsequently to vent thepressure chamber through the valve means and independently of the pilot valve while said first plug element remains in ductblocking position,- means for actuating said valve means, and a one-Way-acting relief-type valve in by-passing relation to the first mentioned plug element of said valve means for enabling venting of said pressure chamber by the pilot valve after the duct is blocked by the first plug element of the valve means and before the second plug element operates to efieot venting of said pressure chamber.

3. In combination with a hydraulic relay speed governor comprising a main speed responsive means including a pilot valve and a regulating servo-motor controlled thereby; a subservient low-speed-responsive valve means acting on the hydraulic system in a manner temporarily to take control of the servo-motor away from the main speed responsive means, said subservient valve means including valve sleeve and valve plunger elements of circular section coacting for subservient valving operation, and rotary means connected with one of said elements and maintaining said elements continually in relative rotation.

4. In a hydraulic relay speed governor comprising a main speed responsive pilot valve mechanism and. a regulating servo-motor controlled thereby and normally movable, a predetermined distance in opposite directions for fuel on and fuel off regulation, a subservient valve mechanism in a feed line of the servo-motor and operable to 'block passage of hydraulic fluid to the servo-motor, lowspeed responsive means controlling the valve in a manner tending to block said passage of fluid to the servo-motor, and

' movement.

fol ow-11p means connecting the ervo-motor and subservient valve meohanisminamanner to cause completion of said blocking operation durin a t i al portion only of the me! on" 5. In combination with a hydraulic regulating serv -m t ro a hydrau i may s eeds ve nqr having a ain speed respon iv p ot a ve mechanism normally controlling said servo-motorga slidable valve sleeve having axially spacedports connecting different portions ofafluid feed of the servo-motor through the intennediary of; the valve sleeve, a valve plunger h'avinglands spaced in bridging relation tosaid' ports, axsub servient low-speed-responsive mechanism connected with the governor and controlling the .valve plunger upon deceleration ina manuer tending to cause one of the lajnds to close, one of said ports, and means for transmitting the motion of the servo-motor to the sleeve during part only of a complete stroke of the servo-mm tor in one direction to complete closing of said last mentioned port. I V r 6. Mechanism according to claim .5, wherein the sleeve has an additional normally closed port communicating with a low pressure space of the governor and wherein one of the valve plunger lands unseals said additional port to ven t fluid from the servo-motor ther'ethrough when the sleeve is moved to effect complete closing of a port as stated. l

7'. In a hydraulic relay speed governor, a. main speed responsive control valvemechanisln and regulating servo-motor controlled thereby, a subservient valve mechanismand low-speed-responsive means for adjusting the same, additionally to control the servo-motor, said valve mechanism comprising a slidable valve element connected to said low-speed-responsive means for operation thereby and a coacting slidable valve element v arranged to Ibe'shifted by the servo-motor to complete a subservient valvingoperationv by said valve mechanism and an adjustable abutment on the last mentioned valve element'serving-o'perw tively to connect the same with the servo-motor during part only of a regulating movement of the servo-motor in one direction.

8. In a hydraulic relay speed governor, a main speed responsive control valve mechanism and a hydraulic servo-motor controlled thereby, a subservient control valve operatively associated with the servo-motor in a manner to enable the latter valve to take control away from the main speed responsive control valve mechanism at times, a low-speed-responsive ball head mechanism including fly-balls connected with the subservient control valve, a coil compression spring outwardly beyond the fly-balls from the valve .and opposing the action of the fiyballs, and means 'rotatable with the 'ballhead, carried on a rigid portion thereof and operable to adjust the compression of the spring.

9. In a hydraulic relay speed governor, a power case and speed responsive main control pilotvalve mechanism carried thereby, a regulating servo-motor arranged for control by the pilot valve, a unitary block for the servo-motor separable from the power case, a subservient control valve for the servo-motor including a valve plunger and a valve guide in a bore portion of the servo-motor block and a low-speed-respon-'- sive ballhead mechanism operatively connected with the subservient control valve plunger and supported for rotation by the servo-motor block.

10. In a hydraulic relay speed governor, speedangsta responsive pilot valve mechanism, a hydraulic regulating servo-motor controlled by said mechanism, "asubservient control valve including a valve plunger arranged in the hydraulic system of the servo-motor and adapted to be moved many for "subservient control of the servoniotor, a low speed-responsive ballhead mechanism having'fiyballs operatively connected with thevalve plunger, and a rod axially aligned with the valve plunger and supported independently of the ballhead for operating the valve plunger independently of the ballhead mechanism.

11 In a hydraulic relay speed governor, speed responsive, valve mechanism and a regulating servo-motor controlled thereby, a subservient valve mechanism including a valve plunger also arranged'to control the servo-motor at times, a low-,speed responsive ballhead mechanism connected to the valve plunger and including flyballs having athrust plate resiliently maintained in operating abutting contact with a rigid portion of the valve plunger, a sliding connection between said rigid portion of the valve plunger and the thrust plate, and a rod aligned with said rigid portion for operation of the valve plunger independently of the position of the fiyballs'and thru n te- 12,. Mechanism according to claim 11, wherein pressure operated means connected with the rod normally prevents the rod from actuating the valve plunger, and spring means operates the rod axially npon "failure or partial failure of pressure n s id. m ns l c h 13. In' a hydraulic relay speed governor, speed responsive control .valve means and a hydraulic speed regulating servo-motor controlled thereby, avalve including a valve plunger operatively associated with the governor 'for performing a sub servient l controlling operation on the servornotor, a rod arranged for operating the valve "plunger, a bellows in fixed position on the governor and-having an apertured thrust plate for a1) t nent with the rod adjacent the aperture 14. In a hydraulic relay speed governor, speed I responsive control valve means and a hydraulic speed regulating servo-motor controlled thereby, a valve including a valve plunger operatively associated with the governor and arranged for performing subservient control operations on the servo-motor, said plunger having an operating stem, low-speed-responsive means having an operating connection with the valve plunger stem, a remotely controllable motor and a rod connected therewith and aligned with said stem for operating the latter by the motor, and a hand operable rod aligned with the first mentioned rod for operating the valve plunger independently of the low-speed-responsive means and motor.

15. In a hydraulic relay speed governor for prime movers, speed responsive valve mechanism and a speed regulating servo-motor controlled thereby, a subservient valve mechanism including a valve plunger also arranged to control the servo-motor at times, a ported valve sleeve cooperable with the valve plunger and arranged to be shifted by operation of the servo-motor during part of a regulating strokethereof in power-input increasing direction, yielding means normally maintaining the valve plunger in an inactive position with respect to a. port of the sleeve, and an adjustable load limit device openatively associated with the valve plunger and capable of moving the valve plunger into positions rendering the movement of the valve sleeve effective to cause cessation of movement of the servo-motor in said power-input-increasing direction.

ALBERT KALIN.

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