US2610050A - Load-limit apparatus for hydraulic engine governors - Google Patents

Description

J. S. DALE Sept. 9, 1952 LOAD-LIMIT APPARATUS FOR HYDRAULIC ENGINE GOVERNORS 2 SHEETS-SHEET 1 Filed March 16, 1951 INVENTOR. jgep a &@M ATTORNEYS.

, Sept. 9, 1952 J. s. DALE 2,610,050

LOAD-LIMIT APPARATUS FOR HYDRAULIC ENGINE GOVERNORS Filed March 16, 1951 2 SHEETS-SHEET 2 INVENTOR.

ATTORNEYS.

Patented Sept. 9, i952 LoAnmIMrr APPARATUS menstrual: f y JENGINEGOVERNQRSTQM Joseph s. Dale, Rockford, 111.; that. that.

Hydraulic Controls, 1 poration of Illinois IQFApplicationMaiehlG,1951,ScrialNo.215,923- (c1. 2.64:3).

l 2 Claims.

This-invention relates to governor apparatus; in particular, it relates to improved mechanism, adapted for use in acentrifugal governor of the type employing a hydraulically-actuated servopiston, for limiting the load on the prime mover being governed and for controlling the response rate of the governor to speed changes.

Large diesel engines are almost invariably controlled by an engine governor, the function of which is to hold the engine at a substantially constant speed despite variations in load. This is accomplished in most cases by providing in the governor a centrifugal speed-responsive element which is operably connected to the fuel-supply control of the engine. l While mechanical governors are still used to a considerable extent, the most satisfactory engine governors are of the hydraulic type, in which the speed-responsive element controls a pilot valve the function of which is solely to guide the flow of hydraulic fluid and therebyto alter as needed the position of a servo-piston mechanically linked to the engine fuel control.- The advantage ofthe hydraulic governor over mechanical governors. lies primarily in the fact that theenergy required for moving the hydraulic fluid and for actuating the servo-piston is supplied by a pump, and the work actually performed by the pilot valve is negligible in amount. Such a governor, therefore, can be much more sensitive to changes in speed resulting from load variations than a mechanical governor, since the worlg required for movement of the fuel supply control of the engine must in the mechanical governor be supplied by the speed-responsive element itself. r This invention is primarily concerned, therefore, with engine governors of the hydraulic type. Such governors, if carefully designed and manufactored, are amazingly sensitive, the sensitive element beingthe pilot valve. Since the pilot valve isan exceedingly sensitive, delicately-balanced element, and is the heart. of an engine governor of the hydraulic type, it is highly desirable that harsh mechanical interference with, or interruption to, its normal function, be avoided. This invention relates specifically to means for controlling, in an engine governor of the hydraulic type, the maximum rateat which fuel may be fed to thecontrolled engineand the rateat; which changes in speed of the engine are reflected bychanges in the position of the fuel-supply control. Accordingly, it may be stated generally that the primary object of the present inventionis to provide; for an Inc., Rocktordrllls 10.0 .2

engine governor of tthel hydrauhc type, a loadlimiting. mechanism .whereby .the maximum rate of fuel supply can bexconven'iently controlled. by the operatorzwithout interfering withzthe'normal action of the governor pilot valve. l '1. Infurtherance. of. the primary objectxjust stated, other objects of the invention includeithe provision of aconvement visual indicator showing the degree ,of load on theengine atany given time and having combined therewith convenient manually-adjustablemeans for setting the, maximum engineload at any, value desired,.within the performance limits of the engine. 11 V .Another object consists inproviding, in a govern of e d aul c typ a g dinfltcmtml apparatusgwhereby the operatorycan note at -a glance theload on the engine at any-given time. bothin absolute terms and .as a fraction of .the load-limitfor which the governorisset. a Other objects and advantages of myinvention wilhappear as the specification proceeds.

In the appended drawing, I have shown my nve ti as a i -t9 an, en i overnor ot hydraulic type. ,While hydraulic-type governors vary in many respects, they have in common the characteristics that hydraulic fluid is placed under pressure by a pump, isguided to one side or the other of a-servo-piston by means of a centrifugally controlled pilot valve, and the servopiston is mechanically linked to. an engine fuel- 1 supply control, whereby thepo'sition of the servopiston controls the rate at which fuel is supplied to the engine. The present invention is susc eptible of application to any such governor, and it is to be understood that the governor apparatus broadly .disclosed in the appended ,drawing is merely illustrative of hydraulic type engine gov.- ernorsgenerally, 3 1 :5;

In the drawing, Fig. 1 is a front elevation view of a casing of \a governor providedwith my invention, the view showing the. visual ,load;,=indicator and the manually-adjustable; means 1 for load-limiting; Fig.2 is a sectionalwiew. partially broken away, of the governor of Fig. 1, thiszview bringing out the structural details of the reversing valve which comprises an element of my inven tion;'Fig. 3. is a plan :view of the governor' of Fig. partially cut awayto reveal some of the interior structure, the section being taken. along a the line 3-3 of Fig. 1; Fig. 4 is a verticalsectional diate spool .valve' member 35.

ually-adjustable load-limit control to the reversing valve withwhlch it is associated; and Fig. 7

is a plan view of a cam element which forms a governor is installed on an engine, will normally be connected by mechanical linkage to the fuelsupply control. A crank or lever arm 23is keyed to shaft 22, and, at its outer end, crankffl23 has; pivoted to it a link 24. Link 247is pivoted at its lower end to piston rod 25 ofservozpistonl'2fi.

The servo-piston 26 is mounted ior reciprocali movement within a cylinder 21, the upper end of piston rod 25 passing through :thetopoicylinder V 21 in a suitably machined bearing.

A port or conduit 28 provides communication between the upper end of cylinder 21 and ad- ;ioini'ng valve chamberj3l, whilera port 29 11110-7 .vid'es icommunicationfbetween valve chamber 13! and the'lower endofcylinderfl. r a s :Ya'lve chamber 3.1. .;is cylindrical-in shape and carries within it a valve rod-L32- ,con'ta'iningxran upper land 33, a lower: land 34, and an interme- Lands ..3 3 and :34 are machined to slide snugly within valvekchamberi 3l, and the :side walls of valve .memberj35 are similarly so machined, thus providing a partition or isolating wall between thezone of 'cham ber "3| above spool member 35 and "the correspending zone belowlmember 35.

The structure of the'pilot valve'iandhydraulic pump apparatus of the illustrated governor are no t shownin the drawing, since such elements may be conventional and "form no -part of this invention. .A pilot valve with which my present invention may be used is shown, forfeXa-mple, in my U, S Patent No.-'2,'5'71,'842,fissued October 16, 1951. I have, "however, 'indicated' a passage or conduit 3-6and a' passa'ge orjcondu itgjl, each of-which opens intoyalve chamber 31. For'purpo's'es of the present application, it may-be assumed that conduits SS'and-S'lcommunicate with the centrifugally-actuated pi-lot valve of the governor, and that-agreduction in'engine speed will cause the-pilot valve to guide hydraulic "fluid under pressure through conduit 3l, =while-an increase in engine sp'eedwill'cause 'the pilotyalve to force liquid -under pressure through condui't 3fi. 1

":When' valve member 32 occupies'the position shown in Fig. 2, which is the normal operating positionjhydraulic fluid forcedth-rough conduit '31 'in'toi the lower -:end of chamber 31 will-pass through port- 29 mm cylinder 21 and-raise"servopiston 26, thus rotating shaft 22 in thedirection to increase the rate of fuel supply'to the controlled'engine; Simi-lai'ly hydrauhc fluid forced through conduit 36 will pass through 'the upper portion of chamber 3i and through port '28 into the upper end of :cylinder 2-1, :thu's forcing the servo-piston I126 downward and causing a decrease in the rate of fuel supply 'tothe engine.v

In'either casefescaping 'fiuid irom the end of the cylinder 21., into which the servo-piston S26- is advanc'ing will be provided 'for'in the pilot valve structure. In :other words, awhen'high pressure fluid .in conduit :36 is forcing the servo-piston downward, vent for the hydrau-lic fiuid beneath pistonx26 :is provided by way of 'conduit 31, :an'd viceversa. I I i. i

The arrangement justdescribed is conventional inwengine governors of the? hydraulic type, calthough the provision of the spool valve 35, with its associated apparatus, is a novel contribution of my own, first described broadly in my earlier and co-pending application, Serial No. 139,076, filed January 17, 1950.

The upper end of valve member 32 is connected 7 by means of linkage comprising arm 38, link 39, and link 40,. to a disc 4|, to which link, 40 is pivoted at its upper end.

Disc 41 is journaled for free rotation on a hollow shaft .42 which is itself carried in a journal bearing :43 formed-in the forward face of casing 10; At its forward end, shaft 42 is provided with .a dial plate 4.4 swaged or otherwise affixed to shaft 42:50 as to rotate with it. Dial plate 44 is a visual indicator of the degree of load imposed on the engine atany given'time.

' Therear'end of shaft 42 carries a'gear member 66, mounted and adapted for cooperation with a vertically-disposed rack 41. Rack 41 is slideably mounted on a suitable bracket 4s carried by frame .1 0". Rack l meshes with gear 46, and is equippedat its upper end with a pin 49 carried within a slot cut into'the end of projecting end portion 50 0f lever .23 heretofore mentioned; As may beseen from Fig. l, rotationkof shaft "22 which is mechanicallycoupled-tothe-,engineiuelsupply control, will cause rack 4! to 'rise oriall and willconsequently lead to rotation of gear-4 5. Since gear 45 and dialplate ;44 :turn-together it willbe, apparentthatt-he angular positionofdia-l plate 44 at -any given time -is a direct ,indication of the rate of fuel supply" to the :engine ,at :that time.

Turning now to the be noted that'its rear face is cut awayjtoprovide female conical surface, :in which a jclutch cone 1'52 rides. Cone 5.2 is equipped :ati-ts rear jeotion :54 thereon. The forward ,axial .facejof -cone:52 receivesiafshaftzi'fia whichiscarriedwithin --t-he :hollow interior of, shaft 542-; the forward end or -shaft ,Efijcarries :an indicatorknobfifi spli edthereon. Thelextr'eme outer :endof shaft 55 fispthreajded toxreceive. a flock-nut '51, which may be provided :with va L-knurled rim .foreasy thumb-andefinger operation.

vIt will ;be seen from the foregoing description that flth'e female conical surface of .gear It and the oonicalsurface, 5.2;cooperate toiorm, a clutch whichrwill lock together cam element 5.3 and gear s rfi' whenever lockenut '51 issin at'tighte'ned position such that the cooperating clutch parts are gripping tightly.- When lock-nut'fil 'has been loosened,,however,gear'24'6 and indicator dial'M can turn independently of knob 56 and cainelemerit-=53.

. ;Bisc 4l,.:on 'theside opposite the pivot-which holdslink .46, carries an elongated pin 58, shrinkfitted or otherwiserigidly secured to thediscin a position parallel to its axis. Pin --58 extends beyond disc 4 l a short distance in the direction towardrthecasing l flgand that-end of pints serves:as,.a:pivot for a link-59 extending upward and :terminating in a manual plunger 60 extendingifrom the top of the governor'casing. Plunger 60 serves .as a manualshut-down device; itsoperatiion .will be more fully described hereinafter.

The other end of p'inf-58 extends inward-1y for a-Lsufficientdistance to cross the locusof projec tion "754, so Lthat as cam member 53- rotates, it will,:at-apoint-nearrthetop of its path, engage p'in;.58 and thus force disc Alto rotate with cam member-53a i To :facilitateiise of my I load-limit mechanism,

details of ;.gear 4.6, fit may .5 an indicator arrow or hairline 6| may be placed on the instrument panel, and graduated marks for cooperation therewith may be placed on the face of indicator dial 44. Similarly, an indicator pointer or hairline may be placed on knob 55.

Operation In the operation of my load-limit control, the operator will first loosen lock-nut 51 and turn knob '56 until the indicator thereon is pointing to the graduated mark or dial 44 which he desires to represent the load limit. The operator will then tighten lock-nut 51 and thus lock together for rotation as a unit gear 46, dial 44, knob 56, and cam member 53.

The relative positions of knob 56 and cam member 53 on shaft 55 are such that projection 54 is brought into contact with pin 58, at or slightly before that angular position of gear 46 at which the pointer on knob 56 is directly opposite hairline 6| on the panel.

The operation of the apparatus described will, therefore, be as follows: When the controlled engine is started, its fuel supply will be fixed by the governor as a function of the load without any interference whatever from the described apparatus, so long as the load is lower than the value fixed by the operators adjustment of knob 56. When that load limit is reached, projection 54 will engage pin 58 and force a slight rotation of disc 4|, which, in turn, will force a slight upward movement of link 40. That movement will result in raising valve member 32, thus reducing the effective area of ports 28 and 29, and slowing down the further movement of servopiston 26. If the load continues to increase, Valve member 32 will be raised to a position at which hydraulic fluid is by-passed around the lands of valve members 35 and 34, thus creating equalized pressures on the respective sides of the servo-piston 26 and thus preventing further movement of the servo-piston.

Reduction in engine load below the predetermined value will cause rotation of cam element 53 in a clockwise direction (as viewed from the front panel) and pull projection 54 out of engagement with pin 58. This will restore the governor to its conventional operating position, and the governor will thereupon control the engine in the usual way.

Manual pressure on plunger 60 will raise the valve member 32 to the point at which hydraulic fluid from port 31 will be routed into the chamber above servo-piston 26 rather than below it. This will cause a reduction in the speed of the engine, and the pilot valve will respond by forcing still more hydraulic fluid through port 31. This operation will continue until the en gine has been shut off. The details of this shutdown device are disclosed in my oo-pending application, Serial No. 139,076, filed January 17, 1950, and are not claimed herein per se as a part of the present invention.

The modification of Fig.

A modification of the apparatus just described is shown in Fig. 5; that structure provides a control over the normal position of disc 4| and thereby permits the operator, by a simple screwdriver adjustment, to control the normal degree of opening of the ports 28 and 29. That result is accomplished by providing a small radial projection 65 on the edge of disc 4| and providing, for cooperation therewith, a tapered stop-screw 66, equipped with a lock-nut 61 and carried in a small boss or projection 68 extending inward from the casing of the governor. If desired, as a matter of mechanical convenience, projection 65 may be displaced axially from the principal plane of disc 4|. Adjusting screw 66 corresponds functionally to the apparatus shown in Fig. 15 of my aforementioned co-pending application, and it is, accordingly, not claimed per se as a part of the present invention.

It will be understood by those skilled in the art that many changes and variations in matters of detail may be made in my invention without departing from its spirit; it is, accordingly, my desire that the illustrated embodiment be regarded as exemplary only, and that the scope of my invention be determined primarily by reference to the appended claims.

I claim:

1. In a hydraulic engine governor having a casing, an output shaft, a cylinder, a servo-piston reciprocable therein, a pilot valve, and a conduit circuit adapted to carry hydraulic fluid from the pilot valve to the respective ends of said cylinder, a load indicator comprising a dial mounted for rotation externally of said casing, mechanical coupling means between said output shaft and said indicator dial operative to compel rotation of said indicator responsively to rotation of said output shaft, a shaft mounted for rotation coaxially with said indicator dial, said shaft passing through said dial, a cam carried by the inner end of said shaft, a manually adjustable knob carried by the outer end of said shaft, rotation of said knob permitting the selection within a range of values of the relative angular positions of the indicator dial and the cam, means adapted for releasably locking said cam and said indicator dial in a selected relative position, a cam follower mounted for free rotation coaxially with said indicator dial and said cam shaft, an adjustable valve in said conduit circuit, and mechanical connecting means relating the cam follower to said adjustable valve operative when the cam engages the cam follower to alter pressures in said cylinder and thus to prevent further movement by the servo-piston in the direction tending to move the cam into engagement with the cam follower.

2. Apparatus according to claim 1 wherein the manually adjustable knob is splined to said cam shaft, and wherein said cam shaft and said indicator dial respectively are provided with shaped surfaces adapted to form a friction clutch, and wherein said locking means comprises a lock nut on the forward end of said cam shaft operative when tightened to pull the shaped surfaces together into firm frictional engagement.

JOSEPH S. DALE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,312,958 Caughey Mar. 2, 1943 2,324,516 Kalin July 20, 1943 2,384,340 Reggio Sept. 4, 1945 FOREIGN PATENTS Number Country Date 282,126 Germany Feb. 17, 1915

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