5 houging. @The otiter end of- this spindle that ptoJect@ -beyond the housing is providedwith a crankarm 80 to which manually operated ineans a-re connected for rocking: the spindle to ope,-ate the brake band 69 to: constrict it upon or loosen it from:the brake-druni 67. When the brake struc-: ture is tightened during operationiof the rotor shaft, the rotation of the clutch mernber 60 will be -arrested together wit-h the rotor shaft to. which @@-The bevel gear 62 meshes with a bevel pinion 81:that is formed upon a shaft 82 which is disposed tith its; axis @oblique to the axis of rotation of,@the transmission assembly, and it is journaled b@:bearings 83 and 84 in- a -hollow boss 85 prefer- i5 ably cast with t.'tie holsing ID. One end of this shb,ft 82 is provided witii an attaching flange 86 ha,Ving intemal splines for operatively connecting the shaft to the instrumentalities (not shown) for transmitting tbrqu6@ to the control rotor or 20 other devices of the helicopter or@other aircraft. Pressure lubricant from the pump SI is fed to, the various operating@parts of the transmission assembly throu,ah an oil-distributing system of ducts and the like. The ducts 42 are adapted to 2,5 discha.rge into the bores 80 of the countershafts 44 of the transmission assenibly and such discharge is cbnttolled by spring-seated outward presslire valves 89 in the bottoms of the bores BE so that the oil will not be a I dmi I tted to such bores 30 Op @intil the pressure of the lubricant is 'suffir-ient to overcome tii te @on of the control s-orings 90 e nsi that urge the valves into their closed PoAitions. Thereafter'th e oil will -be dischar ged throu- a @h plurality of lateral ports 9 I tb lubricate the adj-a- 35 cent membe.-S of tl-ie assembly. Interposed b-.7 tween ',he - ends bf the power shaft 13 and rotor shaft 14, there is a spring-sebted outwarci pressur6 valve 92 that controls the fi ow of lubricant from the shaft bore 40 into the bore 93 @iii the 40 lower porti6n of sa-id rotor shaft. This valve 92 opera,te@ as a pressure relief valve in the same manner as valve 8 9 to permit passage of Itibricant irito rotor shaft bore 93 when the pressure of the spring 94, and the oil wili illen be distributed to the working parts of the adjacent structute through ducts 95. The hydraulically operated friction clutch assembly that surrounds the power shaft 13 is manually controlled by iristru-mentalities that are disclosed in Fig. 5, wherein it will be seen that the annular lubricant chamber 38 communicates with a lateral passage 96 leading to a discharge port 97 i-n an elongated hollow boss 98. A cupsha@ed sliding valve 99, which controls communi- . @,5 cation between the lateral passage 98 and the discharge port 97, is adapted to be moved by the pressure lubricant to uncover the port so that the lubricant will over'-flow or spill back into the o oil sum,.o 33 when the lubricantis not needed to ' operate the clutch. A plunger rod 100, operated by a bellcrank IC 1, is adapted for longitudinal reciprocable movement in the hollow boss 98, and at its inner end said rod 100 is provided with a r)5 stamped cup 102 to seet an end of a coiled spring 103 that has its other erd seated against a follower 104. Between the follower and the slide valve 99 there is a spring 105 of lighter tension than the spring 103, and at the end of the bore 7o of the hollow boss 98 there is a stop 106 t-hat arrests move,.nent of the valve to the right (Fig. 5). When the friction clutch is released, the pressure lubricant will be by-passed through the port 10 sired to utilizo the pressure lubricdnt O.-opetate the@-piston 26 and frictionally,engage the mem'--, bers: of this ;clutch @ihe bell-crank. is: manually'. rocked to push.the@,plunger, rod 100 inward-@so that the heavier spring 103 Nvill,overcome the lighter @@pring IC 5 to such an extent that follower 104 will:contact Nalve 09 and force. the valve. against the stop 106 and close the discharge or overflow port 97.@ The pressure which is, con-, trolled by valve 92 w-ill then build up in the clutch, chamber 29 and will be effective,upon, the piston 2 6 to f orce it upward and eff e.c.t f rictionalengagement of:.the clute.h plates 22 and,2.4 which,@ will,.operate the transmission gearing to @qtate: the,rotor,shaft 14. The pressure. will likewise open valves 89 and 92 to lubricate the various moving parts. The function of light spring ICU is to maintain a slight pressure for lubrication purposes,when the clutch is disengaged. While this inven@Lion has been described in detail ill its present i)referred forni or embodiment, it will be apparent to persons skilled in, the art,, after understanding the improvements conter plated herein, that various changes and modi-I fications may be made therein without. departing from the spirit or scope thereof. It is dimed in the.a ppended claims to.cov,er all such changes., and modifications. @ I claim, 1. A transmission for driving the inain rotor, and control rotor of a helicopter, comprising a rotatable power shaft and a driven main roto@ shaft, a gear train for effectiiip; torqiie multiplication betvieen said shafts; a clutch for effectiny one-way drivi_ng connection between caid gear train and sai-d main rotor shaft, said clut6h comprisiiig a first toothed member splined to 'd rotor ,3haf t; a eco @ sal s nd toothe,d member ro.@ to@ted by @he oltput member of the gear train and, be4.ng yieldably urged toward the first toothed member to m6sh with the teeth thereof; a bevel. gear carried by the first toothed member; a power take-off pinilon rneshed with said bevel gear f,or driving a control rotor of the helicopter; and@a lubricant overcomes the urge of the v@alve seating 4 -D raanually o.13erated brake assembly connected with@ said flrst to6thed member. 2. A transmission as defined in claim 1, where in the brake assembly comprises a frictioii brake drum connected to the first to6thed member; a consttictable brake-band surrounding said drum' and manually operable means for frictionally engaging said band upon said drum. 3. A transmission for driving the main rotor and control rotor of a helicopter, co I mprising a rotatable power sl-iaft and a driven main rotor shaft,- a gear train for effeclting torque multiplication between said shafts; a clutch for effecting one-way driving connection . between said gear train and said main rotor shaft, said clut@h comprising a first toothed member splined to said rotary shaft; a s6cond toothed member splined to the output member of the gear train" a spring normally urging the second toothed member into meshed engagement with the first toothed member; a bevel gear forined integral with the first toothed member; a power take-off pinion meshed with said bevel gear for driving a control rotor of the helicopter; a friction brake drum secure I d to said bevel gear; a band surrounding said drum; and manually operated means for effecting frictional engagement of the band with the druni. 4. A transmission for driving the main rotor and control rotor of a helicopter, comprising a rotatable power shaft and a driven main rotor 97 and returned to the sump, and when it is de- 75 shaft; a multiple countershaft gean'ng for effect-

7 lnt tOr(!Ut Multlplfdbtion betweeri said shafts. a clutch foi effecting 6ne,@;*ak dilving 'corihection be4ween said g6ar train and @aid main totor shaft, said elutch comprising a flrst toothed member sl)lined to said rotor shaft; a second toothed 5 inember splihed to the 'Output member of the gedririig :and being yieldabl@ urged towaid the first tobth6d inember to m@-sh wit-h the t@eth thereof , ti bevel geor fornl'ed in'tegral with the firit toothed niember; 4n obli4tie w6b betw@ e6n the 10 bdvel @g"r and the flrst to6thed ineniber to j>6si.; tibn igid bev6l gear ih a plane above gaid mem.@ beti a Po-*er taki@-off pinion meshed With soid b@evel gear f6r driving a control rdt6r of the heli-- capt#k-, the Oxis of soid piiiion being oblique td 15 the dxii of the bevel g-ear; and a matiuglly op.; erated brake assembl I y connected with said first toothi@d hiembia 'r. . 5. In 6 p6wer tr@,hsmitting mochanigm for a helicopter, a drive shaft, a drivoii @otor shoft fot 20 dfi,vilig the r6tok 6f the helicopter, A - bogitive oii,6-Way O-Verriiniiing clutch mechanism ad9,@ted @to ebnfiect said shafts to p@rmit overriinnihg of the r6t6f shoft, said clutch ciiniprigirig @L toot-h6d c6llitr s@lined to the rotbit sheift @,nd 25 h6,Ving a biake drum connected to said 6011ar, an axiill@ movable to6thed m6fnb@er drivingly conni6dt6d to the dri@e -sh@ft @tnd erigagealble With the toothed collar, and manually op&rable -frig.@ tion engaging means coacting with the bt@ke 30 dr@@ -aiid en@ageable at Will for a-rregtin@ the rota,tion of the t6othed collar to th6r6b@ - Pie'vent ove @iinriihg 6f the rotor ghaft when the h-elirr 6opter it iround6d 6nd said drive gliaft i. stationars'. 35 6. In a powe@ trammitting mechanism fbr a helicopter, a drive shaft, a driven rotor shaft for driving the rotor of the helicopter, a positive onew,@y ovetfunning clutch mechanigm for coiinectink said sh-afts to @erniit overruiining of said 40 rotor shaft, said clutch coniprising a first - tootlied member secured to the rotor shaft and having a brake d@uni c6ni-lebted td said member, aL sedoiid toothed inember rotat6d by the drive shaft, mearis for yi6ldably urging- the s6c6nd t66thed mem'ber 45 into operative engageffient *ith the :ftrst to6thed member, and manually 6@erdted &rigaging mean s coacting with the brak6 drum dnd j6ilgii@6a@ble at Will !6k arresting totfitic*l of the :first toothed@ momber to preveilt overrunning df the rotoi shaft when the hdlicopter is grounded Etrid said drive shaft is stationaty. 7. In a power transmitting mechariism for a helicopter, E@ r6tary dtiv6 shaft, a driven rotor shaft for driving the rotor of the heliec)pter, a pdsitive oiiia-way ovetrunning clutch mechanism for conriedtin-g said shaftg and -permittirig overrunning of said driven rotor shaft, said oluteh coxiiorising A toothed collar gplined to the rotor shgft and having a brake drum connected to ilaid collar, aii aitially movable toothed member, a helical splined donnection operativ(ily coniiectim said axiany mbvable @to6thed member ahd skid d-kive shaft, means biasihg sgid axiELIly movablo member into operative 6ngiigement With thb toothed collai, the direction of inclination of the, splines of said cohhection.being sudh as to as" said biasing means in effe6ting enga-gement of the toothed collar and a:iially movable niember when said drive shaft is rot@Lted, and manuoilly operable frictioii means opef-able at will and coacting with'the btake drum for arresting rots" tion of the t6othed collar to prevent free r6t&.@ tion of the rotor shaft when said dtive.shaftis sta-tioriar-y. ANO E. KIL-PELA. REI@]@RENCE'S CIET@ED Tli6 f6lloWing tefor6ncea ate o f irevord ln'th6 file of this patent: s TATES PATENTS Number Name Date I-,376,033 Plagg ------ @-: Apr. @6, 1921 1,661,613 Jackson ----- Mar. 6, 1928 1,774,618 Thompson Sept. 2, 1930 1,897,180 Ronk ---------------- Feb. 14, 1933 1,928,191 Van Meurs -------- @ Sept.26,1933 21062,9@O Pritcha-rd ----------- Dec. 1, 1936 2,211,781 Joy et al ------------ Aug. 26, i94O 2;2@6i3O9 GlassmELn Dee. 2i, 1940 2,317,957 Frudden ----- Apr. 27, 1943 - VbREIGN PATENT'S Numb6r id6uiltr@ Date 480,824 Gieat @iitain ------- Julie lt,.1936

Patented July 15, 1959 29603910 UNITED STATES PATENT OFFICE 2,603,106 HELICOPTER TRANSMISSION Ano E. Kilpela, Detroit, Mch., assignor to BorgWarner Corporation, Chicago, Ill., a corporation of IlUnois Application August 9, 1944, Serial No. 548,639 7 Claims. (Cl. 74-665) 2 This invention relates to traiismi_ssion gearing and it is particularly directed to transmissions for driving the main supporting shaft and rotor blades of a helicopter or siniilar aircraft wherein the rotational axis of the asseriably is vertically 5 disposed. It is on@ of the principal objects of this invention to simplify the construction of a transmission gearing of the character contemplated herein, and to improve the effleiency, operation and 10 dependabihty of such transmission gearing. It is also one of the principal objects of this invention to provide an assembly of the character herein contemplated wherein disconnection of the engine or priine mover from the transmis- 15 sion may be readily accomplished so that the motor may be or idled or tested without driving the rotor or operating the shaft that supports the same and transniits torque thereto. Another principal object hereof resides in the 20 provision of means, preferably comprising a positive one-way clutch that will perniit the main or sustaining rotor to idle independently of the power means to effect gradual descent and a safe landing of the helicopter in the event of failure 25 or stalling of the engine. In this connection, provision is made in the present structlixe whereby upon failure of the engine the tail or torque control will be operated during rotation of the main or sustaining rotor through instrumentalities irl- 30 terposed between aild operatively connecting the main rotor shaft and the take-off sh@Lft that drives the tail rotor. A still further object of the present invention is to provide a lubricating system, preferably of the 35, forced-feed or pump type that effects a positive distribution of lubricant to the various instruinentalities of the transmission. The pump for discharging the pressure lubricant in:to the various ducts or passages is so constructed and locat- 40 ed in the assembly that it is readily accessible and may be removed with a minimum of labor. The pressure lubricant also provides the means for actuating a hydraulic piston for effecting engagement of the members of a clutch that is inter- 45 posed In the transmissiori assembly. It is preferred to accomplish the riumerous objects of the invention contemplated herein and to practice the same in @ubstantially the manner hereinafter fully described and as more particu- go larly pointed out in the appended claims. Reference is now made to the accompanying drawings formlng a part hereof wherein: Mg. 1 is a vertical axial section of an assembly embodying,the instrumentalities of the present 65 iiivention, the structure being particularly adapted for use iri aircraft of the helicopter type-, Fig. 2 is a fragmental sectional view 6n the plane of line 2-2 on Fig. 1, drawn to an enlarged scale; Fig. 3 is an enlarged sectional view taken on the plane of line 3-3 on Mg. 1; Fig. 4 is a horizontal sectional view ta oil the plane of line 4-4 on Fig. 1 looking in the direction of the arrows; and Mg. 5 is a horizontal sectional view. taken on the plane of line 5-5 on Fig. 1 looking in the direction of the arrows. The drawings are to be understood as being more or less of a schematic character for the purpose of disclosing a typical or preferred form of the improved transmission gearing contemplated herein and in these drawings like @ reference characters identify the same parts in 'the several views. The form of this invention which is shown in the drawings preferably embodies a suitably shaped housing 10 that is anchored in any suitable manner to the body or framework of an aircraft such as a helicopter, and there are axially aligned bearings I I and 12 respectively in the lower and upper portions of said housing-. The drive shaft 13 is rotatably supported in the lower bearing I 1, and the driven shaft 14 for the susa 'ing rotor is rotatably supported in the upper t im bear ng 12. These shafts 13 and l@4 are disposed in axial alignment with each other and there is a speed reduction and torque multiplication of the desired ratio between said shafts that is effected by, means of a transmission gearing assembly that operatively connects the portions of the shafts Within the housing IO. The drive shaft 13 is connected to the engme shaft or other prime mover by means that comprise the flan,ge I 5 splined to the lower end portion of said shaft 13 that is projected belonv th& housing and the bearing I 1, said flange being maintained in place by the usual nut and retainer disc arrangement. Suitable connection (not shown) is made between the driven shaft 14 and the sustaining rotor of the helicopter that op&rates above the body of the aircraft. Within the housing f 0. the ends of the s a a driven shaft 14 terminate adjacent each other, and said end portions of these shafts are journaled in bearings 13a and 14a respectively. The instrumentalities that operatively conne,et the drive shaft 13 to the driven rotor shaft 14 are Preferably;a transmission gearing comprisiiig drive pinion 16. that is loosely mounted. upon

2,603,108 tiie upper portion of the drive shaft 13 beneath the bearings- i 3a, the said pinion being formed upon one end portion of a sleeve 17 that is provided with an erilarged bell-shaped, lower portion 18 disposed in spaced relation laterally of drive 5 shaft 13 and forms a portion of a clutch. The sleeve is freely rotatable relative to drive shaft 13 and rests upon a washer 17a that is seated on a shoulder 13b on I the power shaft 13, the washer being niaintained in place by a snap-ring 17b. 10 The clutch, which is preferably of the multiple@ plate friction type, comprises the drum 19 that surrounds the portion 18 of the sleeve 17 and is disposed in spaced relation- tlfdreto, s;iid drum ' being supported and driven by the niarginal 15 toothed portion of a lateral flange 20 preferably integral with drive shaft 13. Internal splines 21 are formed on drum 19 to drive friction plates 22, and there are external splines 23 on the sleeve 18 to coact and rotate Nvith the driven friction 1-10 plates 24 that are altornately dispt@secl 'bttween the friction drive -plates 2 2. An @Lnnular ptessurb plate 25, oporatirig in the drum 19, transmits force to engage the friction plates 22 and 24, the force being derived from ELn 25 6il-pressure actuated piston 26 bperatitig against the pressure plate -2 5. An annulus 27, driven by slilihes 21 bn the drtim, is positione-d allove the fiictiorl plates 22 and 24, and togl-thor with a . snap ring 28, provides on abutment or stop that '@'O ppposes the a@ction of the pressure plate 25 and piston 26 and limits'the moveraent of the friction clutch plates axially of the drive shz@ft 13. A heavy coiled spring I 8-a surrounds the drivi@ or power sliaft 13 between the sli@eve-supporting 35 *asher 17,a ar@d the inner lower portion of piston ZG to uige the piston downward in a direction to disengage the cltitch plates 22 and 24. Piessiiie fluid, preferably lubricating oil under pressure, is supplied to a chamber ;29, that is '-iO coaxial with the clutch back of the piston 26, Vy a pump 30 tha-t surioiinds a slee,@e 15a @l)lined on the lower portion of drive shaft 13,. and which is abutted by the cyliridric-al @ortion of flange 15 to rotate with saia shaft Ond fi@Lnge. The puMP 45 30 has its movable member secured to th6 sl6eve 15a by a key 3 1. The Puffip Whi'ch is below the bearing I I is held in place by a flange in which may be incorporated a stufft@ng membei or oil seal rmg 32 that is engaged by the sleeve 15a, thus ro Provfding an arrangement ifiat permits the pump to be readily remove I d by dismounting the flan@e 16 and the adjacent sealing flange with6ut dis@- turbing the bearing I 1. The oil for the@ 1?ump passes fibm the sump 33 55 in the bottom of housing I 0 throtigh a - stkainek 34 and passageway 35 to the suction Port of the PumP, and it -discharges under pres'siire into a, feed passageway 36 having a branch 37 communicating with an annular channel 18 sur60 rounding drive shdft 13 above the bearing I 1, and thence through'lateral ports 19 iiito the bore 40 of said drive shaft. One or more oblique passages 41 in shaft 13 establish commiinicatibn between the piston chamber 29 and the shaft bore 6,5 40 so that the pressure fluid is effective upon the piston 26 to frictionally engage the plates 22 and 24 which will operate this friction clutch when .the Oil pressure bvercome@ the urg6 of the @pring 18a. 70 A Portion of the oil under pres@ure is lbd by i3assages.42 away f@om the annular channel 38 to-lubricate parts of the transmission gssembly th b6 latet described:herein. -Th6 transmission -drive, iyinion l@6' that- is og75 4 eratively connected to the drive shaft 13 when thd friction plates 22 and 24 of the clutch are engaged, is meshed with a plurality of fixed gears 43 mounted for rotation upon stationary countershafts 44 that are secured by pins 45 to a ring portion 4G mounted on an inwardly projecting portion of housing IO. The hubs of gears 43 are elongated and are formed with pinigns 47 that i-.iesh with ali internal g6ar 48 forinl'd in the annular flange 49 of a large disc 50 that is integral with a central sleeve 52 surrounding a redu6Od loiver portion of the rotor or driven shaft 14. A radially disposed bracket portion 53 has opOnji1gs ilito which the upper ends of countershafts 44 are iriserted, and the portions 53 and 46 are integral with each other and form a cage for the shafts 44. The cage comprising the portion 53 and 46 is fixed with respect to the housing 10 by any suitable means and including the shafts 44 which at their lower ends extend Into suitable open-ings iii the housing. The deiittal sleeve 54 of the cage, as shown, surrounds@ ttie@ inner bearings 13a and l@4a of the resliective shafts 13 and 14. The internal gear 43, togother with its sleeve 52, is connected to the rotor shaft 14 by iries@ns of a driving device that is preferably a Positive ola:e--way clutch assembly of the toothed ity#ei One member of this clutch coinprises an gnnulgr collar 55 surrounding the sleeve @52 and@movabli@ in an axial directibn thereon throu@h a helidally splined connection SG therewith. @Tliis ebilar- is urged upward against 91 stop-ring 57 by the@thrtwt due to the helically splinedconnection when the engine is driving and by helical. spring @ 59 in@ei-posed between the lower portion of said @ ccillar and the upper face of the disc 50 that catrie! the internal gear 48. The upper edge of collar 55-is castellated to provide axially ext@ending teeth 60 the@t mesh with similar axially extending teeth@ 60 on the other or opposing member 61 of the clutch. This other clutch member 61 cornpriges the lowi@t hub portion of a lorge bevel gear 92 that guirrounds the rotor shaft 14- above th6 positive clutch and has an upper:elorigated sleeve portion 63@ that has a splined connection 64 with sgid rotor @lfgft so that it turns therewith. The sleeve $3i geat 62 and its hub provide the oiltput mernb&r of this clutch and transmission olssembly. The lip'per end of the sleeve 63 abuts the bearing f@2 and,the lower ends of the splines rest upori a; gplit ring @65 that is sprung into an annular groove 96@ in thti adjacent portion of the rotor shaft 14. The brake drum 67 is anchoreci to th6:we)Y@ 68 of the bevel gear 62 in the manner shown,aild'it is surrounded byra friction brgke-bAnd-69 4@) that is provided with the usual terminal 1 ugs It and 71 between which there is interposed- a coile d spring 72 that is under compression to no-tmally urge the lugs in opposite directions away fr6m 6ach other to loosen th6 brake-band 69. @'Ltik 71 is engaged by the'inner-end of a stop bolt 73 the@t is screwed into and through a threade(t-- bo@s @7 , A and it has an outer slotted end, projected throtigh the housing I 0 to permit longitudinal adjustifterit thereof for taking up wear in band 69. The other lug 70 is engaged by the inner end of a plunger 75 having reciprocating longitudinal movextent in a bearing 76, suc movenient being effect6d by a- rotary reciprocable'edge cani 77 that eiigages the other or outer end of said pluriger @75'. 'Citni 77 is secured to the inner@eild of a'ro6k- ' di spm e 78 disposed with its-axis tiansverse't6 th6,,akls,(Jf plun,ger 75 and -.mo-unted@ in- a b6firing@, boss@-79 fornred integral'-with- the@ adjf@tent poiifdn--otthi