US2327216A - Governor - Google Patents

Description

Patented Aug. 17, 1943 oracles f1 213; 7 i i i Harry P;*Reiber, williamsportfila assignorrdf forty-penoerittoArthur H. White, New York,

ApifliczitionEbruary 24, 1941, .Serial No.380,Z33

TMy invention. relates togovernorshon regulators and more particularly to a centrifugallyiresponsive governor tmechanism for imaintainingeaaoredetermined relationshipbetween .the pitchwof the blades of :a cvariable p'itch airplanelpropeller' and the speed ofirotation (Rt P MA, -l-of =the-engine shaft driving the propeller.

.One of-the. objects, of-mylinvention islto provide aisimplergovernonmechanism:ofithe-typeideflned which .can zbB coupled .to the-drive zshaft of an airplane engine and vwhich can he controlled manuallyfromthe cockpit. V V

Another .object is to provide fa -ucentrifugally .operatedegovernor mechanism which is :respfln- .sive to variations in the R.1P.1-5M'.(of .;an engine. shaftito operateassociatedl'mechanism:for varying the pitch of the ,propelleribladeslto:such an extent and in ethe proper-l directional/hereby the 1 desired =-R..-.P.-M. of theshaftvcanfbelsubstantially maintained 1 automatically eat :a predetermined value Anotherobject is l the tprovision of means 5T6- sponsi-ve .to the action of centrifugal force "to electrically-controlta .mechanismdforWaryingtthe .pitch of :the blades .of ranairplane: propeller.

A further object resides in the g provisionrgof vmeans responsive to the action :of centrifugal force for-electricallyeselectirrg -:mec-hanism.l-=for varying-.themitchof the blades lo'fwa'vaniable rpitch propeller, in whichwariati-ons the Idegree =01 centrifugal forces applied to said .means will .correspondinglyvaryztheflowzoizelectrioal:current iin the-selector-circuit. v a

V Anothersobject is .to tconstrut :aagorternorvdfithe above mentioned icharacter wirl-chads :extremely simple in design andconstruction,:sensitivezand efilcientin.operationandwvhich cansbexprfoduced fat'lowicost.

-A"stil1 further objectiofamyzmventiomiytoipromate Msof sthe shaftiat Whichtheagovernor will respond to -eifect; :a vari'ati on inztheqait'ch of the propeller-blades. J

- .Otherobiects :and advantagessofoamyiinvention will become rmore apparentfrom:the ifollowing description of one embodimentrthereof;reference beina made to the accompanying drawing in which:likefreferenceacharactersEaresemployed to designate like parts: throughoutithe: same In the drawing: .Figure 1 1 P'i's longitudinal section 6m governor assembly employingrmyinvention;

Figure .2 is ai vertical transverse sectionftaken "on 1ine-2- -2'o'f Figure l;

Figure 3 is "a section taken on line ""3-"3 "of -Fi'gure1;

Figure 4 is an" end' view taken" in the direction of line 4-1 "of Figure 2 andv'showsipartcof the 'assemblyinlcrossisection{and vide simple means .for spreselecting Tthe azpproxi r drawing :which ill iof myainvention, the g-overnor casing comprises l-thehousinglmembers l' and '2 which maybe sepointed. out that the samev is vparticularly desirable for use in connection with variable pitch ,propellers asiameans ,of automatically varying the pitch oflthe blades in adefinite relationship ..tot.theR.. P.iM. of the engine shaft. Therefore rbriefreference is made to the above identified .copending application .of myself and Jack B.

Reibeninwhidhis disclosed mechanical means for eifecting a pitch variation throughwsuitable gearing and the .timely operation of magnetic clutches-b y the pilot. l

.L'Inoperating an airplane a great demand is vmade upon thelfaculties of the pilot by the necesl sity 1 of constant observance" of numerous instru- -mentsiindicatingrthe performance of the various wpartsioflthecmachine as-well aslthe conditions-o1 iifiight.

Qneofathe duties which require the attention of the pilot of a plane havingavariable pitch pro- ,peller isthat-he mustlfrom time to time adjust the pitoh-of the'lblades inrelation to the R. P. M. of theengine shaft to maintain efficient operation ;.of the plane and engine.

This is particularly "true-in.steepclimbing .or in diving.

The presentin-ventionzis concerned chiefly with =the ..provisionof -means whereby this relationship between shaft RQP. M. and blade pitch can be .-.maintainedautomatically without especial attentioncf the-pilot-as will-more fully appear hereinafter. i- Furthermore, by the present invention tthiS relationshipmay be varied .atlthe will of the pilot as he sees fit by manual adjustment of the governor.

iReferr-ing more *specificallyto the accompanyz tes one embodiment cured together :by means'of the screws 3.

p The housing member A comprises a tubular .portion extending substantially ZUI'lHHY of .the general assemblyaanda cover plate-Q, the latter fittingwsnugly againstthe-open end of the hous wing :me-mbemi :Within the housing-2 a 'rotortla driven by the drive shaft l-journ'aled in suitable thrust wbearings Lathe drive shaft: Sprojeeting outward- Fly of .thecasing as shown and having suitable :ldriving ;connection with :an engine or driver shaft (not,-.shown).

lating material, the ends of the tubes l exten'd.

ing a short distance beyond the ends of the rne-v tallic tubes 8 and 9 as a protection against short circuits around the carbonpiles as will be seen later in this description.

Each of the insulating tubes houses a carbon pile H, that is, a plurality of discs of carbonaceous material each having good electrical conduction characteristics, said discs'being arranged in a pile or in face to face relation as shown.

As is well known, when the pile is put under axial compression, the electrical .resistance through the pile decreases in proportion to the pressure applied and as the discs of the pile tend to separate one from the other, the electrical resistance through the pile increases.

The device is connected with a source of electrical energy as indicated in Figure 5. In Figure 1a binding post i2, insulated at 33 from the casing 2, is connected with an annular conduc to-r l4 retained in an insulating band i5 carried by the casing 2, v I I When two carbon piles are employed, shown in the drawing, I provide a pair of current 001- lection rollers l5 mounted in suitable holders I1 operating against the compression of light prings l8 within recesses formed in the bases l9 to normally thrust the roller outwardly so that they will always be urged into good electrical contact with the annular conductor M. In order to maintain the rollers in proper alignment with the conductor It, the stems 2% are slotted at 2| to receive guide pins 22 carr'ied'in the holders ll. Each of the roller mounts or bases 89 is carried by the rotor 5 but insulated from it at 23, therebeing conductors 24 and 25 leading from the bases #9 respectively to the yoke support 25 which is also insulated at 2! from the rotor 5 (see Figure 4).

In further carrying out my invention, I have provided means whereby apredetermined initial force of compression may be applied to the discs of the respective carbon piles Ii.

of spaced follower plates or discs of metal 28 I will now describe in detail the mechanism shown in the embodiment illustrated in the drawing for exerting forces to vary the compression of the springs 33 or to relieve said forces. a

In the outer end of the axially extending casing member I, I have provided a bearing support 3| for slidably supporting the rack 32. A shaft 33 extends transversely within the casing l and carries a keyed pinion 34 having its teeth in mesh with the rack 32 within the casing. The outer end of the shaft carries a gear or grooved wheel 35 which is connected by a gear train, chain, or cable 35 as the case may be, to a suitable manual control in the cockpit of the airplane. Thus by turning the member 35 the rack 32 and the rod 31 operating in the rotating housing 38 formed in the inner end of the drive shaft 6 is caused to slide to the right or left in Figure 1 depending on the direction of rotation or movement of the member 35. The inner end of the rod is supported in a bearing 39 within' At each endof each of the piles l i, there are provided apair provided with an extension 4| to which a plate --42 is secured. Racks 43 and 44 are secured at one end to the plate 42 and are slidable in the recesses 45 formed in the drive shaft and have their teeth disposed in diametrically opposed directions to mesh with the teeth of the respective pinions 46 and 41. A pin 48 keys the drive shaft 6 with the rotor 5 so that the two rotate together as a unit.

Referring now more particularly to Figure 2, it will be seen that the pinions 45 and 47 are keyed respectively to the rods 49 and 50 which are rotatably supported in bearings 52 carried by the rotor 5,

The rods are screw-threaded inwardly of their outer ends as at 52 and extend substantially parallel to each other. It will be noted that the right hand sections of the rods 49 and 50 in Figure 2 are separated metallically by the insulated sections 53 and 54 respectively. This is essential since the right hand ends of the threaded rods carry the insulated'yoke or equalizing member 55. The insulated yoke 55 comprises a member substantially U-shaped in side elevation as illustrated in the drawing and is internally threaded at 56 and 51 to receive the threaded ends of the insulated rod sections 49 and 50. Intermediate these threaded openings there is provided a guide member 58 operating in the yoke support 25 insulated from the rotor at 21. The outer extremities of the yoke are turned inwardly and engage the outermost follower discs 29 in the insulated tubes 30.

cause the yokes 55 and 60 to move toward each other and opposite rotation will impart a separating movement to the yokes.

It is also to be noted that the yoke 60 need not be. insulated from the rotor since the flow of current through the insulated carbon piles H may be grounded to the rotor and case after it enters the yoke 50. A return current binding post 6| is carried by the casing member 2.

In Figure 5 I have illustrated by means of a wiring diagram how the governor may be electrically connected in a control circuit such as is disclosed in my copending joint application above identified,

The operation of the present invention as illustrated in the. embodiment shown and described is as follows:

The shaft 6 has driving connection through suitable gears or other means or is connected directly with and driven by the engine shaft of an airplane motor. The speed of rotation of the shaft 6 is then in definite relationship with that of the engine shaft. Rotation of the shaft 6 and to separate the discs against the compression of the springs 30, thus increasing the electrical resistance through the carbon piles.

It is the function of the equalizing yokes 55 and 69 to impose a predetermined force of compression on the carbon piles through the springs 38 and as has been described this is accomplished by sliding the rack 32 in the desired direction by turning the gear or wheel 35.

As the force of compression exerted on the discs of the carbon piles is increased the current conductivity of the piles is increased due to better electrical contact between the discs in each pile. Thus it will be seen that the piles may be put under an initial predetermined compression to determine the current value which shall be allowed to pass through the piles.

This value may be defined as that required to operate associated blade pitch controlling mechanism including electrical relays, magnetic clutches and suitable gearing such as is disclosed in mysaid copending application. With such an initial compression applied to the piles, it will be seen that in operation there will be a definite relationship between the R. P. M. of the engine shaft and the degree of centrifugal force operating upon the disc of the carbon piles to overcome this initial force of compression. As the initial force of compression through the springs- 30 is overcome by outward movement of the discs I l the electrical resistance through the piles is increased and the current passing through the piles is decreased.

Such a condition as is explained above will exist, for instance, when the airplane engine speeds up as in diving with the blades set at a high pitch angle Under such conditions, it is necessary to vary the pitch immediately to maintain the desired R. P. M- of the engine shaft. The governor is set by the pilot toa proper designation whereby a predetermined R. P. M. of the shaft can be maintained. Any tendency of the engine shaft to exceed the desired R. P. M. value will of course result in an increase in the R. P. M. of the rotor increasing the centrifugal forces on the discs of the two carbon piles, sufiiciently to overcome the forces of compression applied through the springs 30, at the same time slightly moving the discs outwardly from each other and thereby increasing the resistance through the piles. A current drop results which is sufiicient to actuate a high pitch relay closing a circuit to operate a magnetic clutch to further bring into operation associated means to increase the pitch of the blades of the propeller.

Such an increase in blade pitch will of course increase the load on the engine shaft and cause it to slow down to the preselected R. P. M., whereupon the relay I0 is de-energized.

If the airplane engine slows down as, for instance, in steep climbs, the action of the gover' nor will be such that due to the decreased R. P. M. the centrifugal forces exerted on the discs of the piles will be overcome by the forces of compression exerted through the yokes 55 and 6H and the springs 30. The electrical resistance through the piles is thus decreased increasing the current value passing therethrough to a point sufiicient to operate the low pitch relay H, Figure 5. Thus a low pitch magnetic clutch is energized bringing into operation associated mechanism for decreasing the pitch of the propeller blades. Under these conditions the R. P. M, of the engine shaft builds up until the current value passing through the carbon piles is such that the low pitch relay 'H is de-energized.

From the above it will be seen that I have provided a'simple yet extremely sensitive means for .efficiency and automatically controlling and governing the rate of rotation of an airplane engine shaft under varying flying conditions, so that a substantially uniform R, P. M. of the shaft can be maintained.

Furthermore, by means of my invention, I have provided a governor which eliminates lag or break in response to condition requiring a pitch change. Another advantage resides in the fact that the present invention provides means of the above named character by which pitch changes can be made gradually and due to the inherent sensitivity of the device a relatively small change in blade pitch will be required to maintain a selected R. P. M. of the engine shaft.

Various changes may be made in the details of construction and arrangement of parts of my invention without departing from the spirit thereof or the scope of the appended claims.

I claim:

l. The combination with a variable pitch propeller, of an automatic control for maintaining a preselected rate of rotation of an engine shaft driving the propeller, said control comprising a rotor having driwing connection with the engine shaft, means carried by said rotor and responsive to the action of centrifugal force for obtaining a variation in the pitch of the propeller blades when the rate of rotation of the shaft varies substantially from a preselected value, said means including an electrical pitch control circuit and carbon pile resistance elements in said circuit and mounted transversely on opposite sides of the axis of rotation of the rotor and means for exerting an initial force of compression upon said carbon piles, said last named means comprising a member slidable axially of the rotor, and compression members movably simultaneously in opposed directions upon movement of the slidable member in one direction to exert forces of compression inwardly of the ends of the respective carbon piles.

2. The combination with a variable pitch propeller, of an automatic control for maintaining a preselected rate of rotation of an engine shaft driving the propeller, said control comprising a rotor having driving connection with the engine shaft, means carried by said rotor and responsive to the action of centrifugal force for obtaining a variation in the pitch of the propeller blades wh n the rate of rotation of the shaft varies substantially from a preselected value,

said means including an electrical pitch control circuit and a carbon pile resistance element in said circuit and mounted transversely of the axis of rotation of the rotor and mechanical means operating axially of said rotor for exerting an initial force of compression on said carbon pile, said last named means comprising a member slidable axially of the rotor, and compression members movable simultaneously in opposed directions upon movement of the slidable member in either direction to exert forces of com pression inwardly of the ends of the carbon pile and equalizing resilient members between the respective ends of the carbon pile and the respective compression members. I

HARRY P. REIBER.

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