US2329174A - Engine starter - Google Patents

Description

Sept. 14, 1943. J. w. FlTZ GERALD ENGINE STARTER Filed Aug. 1. 1941 Patented Sept; 14 1943 l I 1 Panama STARTER John FitzGeraId, Milwaukee, Wis, assignor to Q I Briggs & S'tratton Corporation, Mjlvvaukee, v

' TW is; a corporation of Delaware" Application ugust}, 1941; Serial NGAOEJHQ 21 Claims; (o1.74-'7) This invention relates to enginestarters, and

I refers particularly to the so -called automatic type of starter wherein inertia is-relied upon to effect relative rota't ionfbetween a starter gear or pinion and its power driven actuator top'ropel the pinion to and from"operative drivingt'ei igagement a -i U,

Due to the' adventflof 'o'il'clutches inarito'mo biles, the use of these automatic starters has en-o iwit h' the flywheel ofyan engine to be countered a serious problem. As, will be readily V under low' temperature conditionsj Under these condil aions the' oil filinfriction freezes the pinion to the starter shaft Inertia, therefore, is not enough to assure the necessary relative motion between the, coactingz screw th11eaded3parts and as a consequence I the piniorr instead-cf -moving:

orwardlyntolmesh,withathe r n g l -takencthrough Figure "It on the .planewcf-theline directed was provision of simple but .effective'smeansforeverrevolveswithiits actuator; '5

"This invention is; therefore,

the ring "gear;

'=Ano'the'r o'b'ect' or this iii-ventio'n js the 1pmvision of "centritugally 'respon'sivemeans .fcr retardin'g the-retraction v -of the pinion to prevent objectional rebound.

Still another object of *thi'sfinve'n on A topro vide a single centrifugally-responsive means for advancing the iiinion and also-retarding its Iretraction. o Withv'theabov'e an'do'ther; objects in view which will appear 7 as the description 'proceeds, this" invention resides jin'th'e novel rcons'truction, commade as comefiwithin'.the:scopefof the iclai'ms.

coming this objectionable possibilityand insur ing translation bf "the-Dinion.;irito'- m'esh' withthe ring' g'ea'r eventhou hthe crew threadediparts ma be Is'tuck together ty 'a; e agealea 'oil film.

, With avi'w'toward stIUcturaFsimplicity;it is a furtherobject of this -invention to utilize centrifugal force to 'eifect thefnecessarv" relative rotation {between the: starter ea Il actuator.

Lenqf 'e t a offth inveht niisto rovide; means for augmenting inertia fin eiiectin'g'i rela? tive rotation between thefistarter "gear and "its e tuato giiwhic depe d's' m- I off the' autoniobileo'r'itslenginejand which is entirely self ccnt'ained within starter mec'ha- Hism ",Mbre specifically; object of this inven-ithin to provide'fastarterfhaving "a centrifugally m i i h e 1 1 98?m llei qn qma ried b yt the-power driven-actuatorto turn thereno other function;

with and connectedf-to "the starter gear-in such m hner hat ts esm ,.0:-. 2 I i a Q-ieb the ta;rter.1 e cetw h re ect. to; its.

bination' and arrangement of parts' substaintially as hereinafter ,ilescribed' 'and' rnore particularly I defined b'ythe appendedclaimsgit being under I stood that such changes in the "-pre'ciseernbodi- I ment of the; hereindisclosed? invention may be The accompanyingidrawin'g i1l'ustrates"one coin plete example of the physical embodiment of the invention constructed acccrdingl'to the best mode so far devised for the ractical"application of the-principles thereof, andin which:

Figurel is a view partly in sideelevationg and partlyin'lon'gitudinal section of an engine starter embodyingthis invention'; A

-1FigUIe 2 is an enlarged cross (sectional view,

Figure 4-is' 'a-perspective vi'ewfcf ,;;the entire I starter.- 1

parts, the numeral '5 designates a power driven driveshaft wl'iich'ispreferablythe armatureshait tion with the 'shacft'i provided .bya rubberrring- I2 Confined between f iangesrl3andrldmThelfon tarter- With I i I 1 Referring now particularly to,- the a ccoinpany in'gdrawing in whichli ke numerals designate like mer of these flanges is fixed to the screw threaded actuating member H and the latter has a hub l5 by which it is fixed to the drive shaft 5.- A cup-shaped outer shell I6 having its open end secured-to the flange l4 encloses both flanges and the rubber ring and by a medial shoulder limits motion of the flange l3 away from the flange 14. The rubber ring is thus held under pressure between-the flanges to provide initial frictional driving engagement to transmit torque I resiliently from the shaft to the screw threaded actuating member. I I.

Hence, when the drive shaft begins to revolve,

the inertia of the starter gearand its sleeve holds the same stationary while the actuator l l revolves and demesh type. the, combination with: a power driven member; and amember connected with the starter gear and threaded to saidpower driven member so that relativerotation between therein to propel the'pinion' forwardly into mesh' v with the ring gear. Forward propulsion of the pinion is. limited by the engagementof a stop flange IT on the pinion extension with the end of the shell l6 which is flanged inwardly.

Under normalconditions, inertiamay berelied upon to effect the necessary relative rotation between the -pinion and its actuator but if the starter must ,operatein conditions where it is subjected to excessive oil as. in engines. equipped with oil clutches, the required free running fit between the pinion sleeve and. actuator cannot be maintained especially in cold weather.

Under/such conditions, the oil film which is excessive congeals and must be broken to insure advance ofthe pinion into mesh with the ring gear. .To this end, the front end l6 of the shell has a weighted centrifugallyresponsive leverl8 pivoted thereto as at IS. The outer Weighted end of this lever is coupled to one endof a brake band said members effects translation of the starter gear into. and out of mesh with the ring gear of the engine to be started; of a centrifugally responsive device; and means actuated bythe centrifugally responsive device in consequence to its responseto centrifugal force forefiecting the necessary relative rotation between said members to advance the starter gear toward the engine ring gear.-

-.2..In an engine"; starter of theautomatic mesh and demesh type having a powerdriven member and-a startergear'memberscrew threaded tolflsaid pcwer'drivenmember; means for augmenting inertia normally relied upon, for effecting relativerotation' between said members as the starter begins to operate to insure advance of the starter gear, said means comprising a centrifugally respons'ive member revoluble with the power driven member and adapted to swing out from a normal" position in responseto centrifugal force and, a.,driving connectionibetween said centrifugally responsive member and the starter 20 preferably by means of a. chain link 2,! engaging in a loop on the lever.

I The opposite end of the brake band "is connected to a'fixed anchor'as'for instance the pivot l9 by means of a tension spring 22. Hence; when the "starter is stationary these parts assumethe sameQthispull on the band rotates the pinion with relatio-nto its actuatorv l Lg. The direction ofrotationisindicated'by the arrow:23, and is such that forward translation of the pinion takes Place; q 7

After the engine starts and the pinion-over runs the actuator, it' is retracted' in the normal manner but by virtue of the engagement of the brake band with thepinion' sleeve the retraction centrifugal. force ceases to hold the weighted lever out and the spring 22 restores the parts to their normal positions, a turning moment is i1n-- parted tothe pinion in the" direction necessary to retract the same. 1 w a j Hence, the means; here provided for augmenting inertia to insure meshing of the'start'er pinion with the ring gear also has an anti-bounce function which is highly desirable. 7

Inasmuch as the brake band is constantly maintained'under tensionby the spring 22and is wrapped about the pinion sleeve at'all times, it

follows that an anti-creep function is inherent in the'str'uctu're of this invention.

Thisinvention' also makes possible a very degear member for. turning. the starter gear memher with relation to the-power driven member in g the directionnecessaryto propel thestarter gear forwardly. p

3. In 'an engine starter, the combination with: a starter gear and power driven means having a part thereofprovided with a screw threaded connection with the starter gear; 'centrifugally responsive means rotatable withthe power driven means and having a motion transmitting connection with the starter gear rendered effective upon response of said means'to centrifugal force, said centrifugally-F-responsive means acting on' the starter 'gear upon initial operationof the starter to augment inertia normall'yrelied uponto effect relative rotation between the starter gear and said .parto'f the power driven means'and being operable to effect the, relative rotation between the starter gear'and power driven part necessary to effect propulsion ,of' the starter gear toward l of the pinion is materially slackened. In other- I words; the brake band" imposes a drag; "on the pinion to reduce 'the speedolfits rotation. This effectively prevents rebound. :Moreover, when operative position-asthestarter begins to operate.

4;;In an engine, starter: astarter gear movable to. and from mesh withthe rinlggear of an engine to be started; a powerdriven a actuator for the starter gear; a screw threaded connection be-v tween the actuator and the starter gear sothat relative rotation between said parts in one direction propels. the pinion forwardly into mesh with the ringgear; a Jweighted member pivotally mounted to revolve'with the power driven actuator, and to swing" out on its pivotal mounting in response, to centrifug'alforce;v and'means connecting said pivotal 'member with' the starter gear and utilizing the outward swinging motion .of said member to effect relative rotation between thegear andits actuator in, the direction necessary to propel the pinion forwardly.

5. 'In 'anTengine'starter; a starter gear movable to and from mesh-with the ring gear ofan engine tobe startedya power driven actuator for the starter gear; a screw threaded connection between the actuator-and the starter gear sothat 2;s 2e,: i-74 I starterigear withaelation to 'the actuator' in rerelative rotation between said parts inone directionipro'pelsitheipinion forwardly into mesh with 'the :ring gear; a weighted :mem'ber 'pivotally mounted to revolve with the power drivemactuator andft'olswingout on its .'pivotalmounting in responseztocentrifugal force; and a member connected with said pivoted weighted member and :friCtiOriallyengaging a part ofthe starter gear .to'turn :the same with relation to its actuator as I :theweighted member swings out in response to centrifugal force. W r.

'6." In an engine starter: a starter gear movable to :and'from mesh with the ring gear-of an engine to. be started; a, power driven actuator for the starter gear; a screw threaded connection'between the actuator and'the starter gearso that relative rotation between said parts in one' direction pro i :pels :theipinion-forwardly into mesh with the ring gearyajweighted member pivotally mounted 't'o starter gear; a screw threaded connection between theiractuator iand the starter gear so that relative rotation between said parts in one direction propels the pinion forwardly into mesh'with the ring gear; a weighted member p'ivotally mountedtorevolve with the .power drivenactw ator and to swing outon itslpivotal"mounting: in response vto centrifugal force; 'aimember partially wrapped about a part ton/the. starterigearand connected with said weighted member, said wrapped member having frictional engagement with said part on the'starter gear-so as to turn the same with relation to its actuator as the weighted member swings out in response to centrifugal' force; and spring means for returning said wrapped member and the weighted member to their normal positions. I v

8. In an engine starter: a starter gear having an internally threaded cylindrical extension; a

spouse :to outward mo'tion'of the weighted ilever byrcentrifiigal 'frorcer and ra fspring connected with 'saidcbrake lbandlforcreturninglitiandithe'wei'ghted 10. In an engine starterz, a .startrifgear mountedifo'r 'translationito 'and from an operative driving-position; ia cylindrical extension on the starter gear; a power :tiriven' actuator fhaving 'a screw threadedconnection-with said starterigear so :that relative :rotation between :the :actuator andthe starter-. geartranslates the 'start'er 'igear to" and :fromroperat'iveapositionpabrake band partiallyiwrapped iabout the cylindrical :extensionof the; gear; :a' s'yielding support for I one end of *the brake'bandtzand:azweighted 'centrifu'gally respon sive :membe'rmounted to revolve-with the 'power drivenkactuatormnd' eonnected :with the l opposite end of Ft'h'e I brake irba'nd v to exert a pull ther e'en as the weighted "centrifugall-y responsive member responds-ito icentrifugal iforc'e to thereby effect to and from mesh with the'ring g'ear of 'anengine to be started; a powerldriven actuator for theling m'ember. t 12. .Intranengine relative rotation between the starter gear and its actuator in a' direction necessary to propel the starter;gear'.:forwardly toward operative position.

, rllzrrIn an 'eng ine 'starterz' power' drivenin'eans including an :actuating member fa' starter :gear connected 'with'the actuating member so ias to beimoved into engagement with :a member: of fan engine "to *be': started in iconsequence to relaitive rotation between the starter gea'r and actuating membem 'and fcentrifugally responsive me'ans' en ergiz'ed-by rot'ation iof the aotuating n'iember and connected withthe starter gear.-'so rthat'response of said means to centrifugaliforce e'flects irelative rotation ibetweeniithe is'tarterigear and the actuat- SItar'terE I a motor driven starterbshaft; aLpinion movable along the shaft into engagementFWith a memberof an engine'to bevstarted; a driving connection 'between the pinion" and said. shaftfioperable, to propel the r pinion alongithe sharit -into mesh with the' 'ri ng gear of an engine to, be started upon relative power driven actuator screw threaded into said extension and operable upon relative rotation between it and said cylindrical extension to propel the starter gear forwardly; a part revoluble with the actuator'and havinga portion thereof adjacent to the cylindrical extension of the starter gear; a weighted lever pivoted to said part; and

a brake band partially wrapped about the cylindrical extension of the starter gear and con-.

nected with said weighted lever to turn the starter gear with relation to the actuator in response I to outward motion of the weighted lever bycentrifugal force. s

9. .In an engine starter: a starter gear having an internally threaded cylindrical extension; a power driven actuator screw threaded into said extension and operable upon relative rotation between it and said cylindrical extension to propel the starter gear forwardly; a part revoluble with the actuator and having a portion thereof adjacent to the cylindrical extension of the starter gear; a weighted lever pivoted to said part; a brake band partially wrapped about the cylindrical extension of the starter gear and connected with said weighted lever to turn the rotation between the pinion andthe starter shaft; and centrifugally responsive means having a motion transmitting connection with the pinion operable upon response of said means to centrifugal force-to insure relative rotation between the pinion andthe starter shaft. I

13. In an engine starter: a pinion movable longitudinally toand from an operative driving position; power driven means including an actuatingmember; a screw threaded connection between the actuating member and the pinion whereby relative rotation between said parts effects longitudinal movement of the pinion; and centrifugally responsive means revoluble with the power driven means and operable on the pinion to effect relative rotation between said parts in a direction to advance the pinion.

14. In an engine starter: power driven means including an actuating member; a starter gear member; a threaded connection between said members whereby relative rotation therebetween efiect's translation of the starter gear member from and to a retracted position; and centrifugally' responsive means .carried by said powerv driven means and "acting on the starter gear member throughout substantially its entire retraction to retard such retraction and thus prevent rebound of the starter gear member from its retracted position.

able endwise therebyl toiand from an operative drivingposition engaging amember'of an engine to be started; andasingle centrifugally responsive means operable-to efiectendwise motion of the starter gear toward its operative driving position and to retard retraction of the gear to prevent rebound. v I 1 4 a t 16. In an engine starter: a power driven member; 'a'pinion; a threaded connection between the pinion and said power driven member whereby relative rotation betweensaidparts effects translation of thepinion to and from an operative driving position; a centrifugallyresponsive member revolublewith the actuating member; and means connecting said 'centrifugally responsive member with the pinion .whereby'response of said centrifugally responsive member revolves the pinion with relation to the=actuating member to propelthegpinion toward operative position and 4 whereby retraction of the pinion is retarded. i

s 17. In anengine starter; power driven means including an actuating.member;.a pinion'having a threaded sleeve; a threaded connection between the pinion sleeve vand said actuating member whereby relative rotation between said parts effects translation .-of the-pinion toy and from an operative driving positionya centrifugally re sponsive member revoluble with the. power driven means; and a brake band connected with the centrifugally responsive member and wrapped about the pinion'sleeve whereby the pinion sleeve is revolved relativeto the actuating member durin operation of the starter'to propelthe pinion 'pinion sleeve.

carried by said power driven meansand operable on the pinion member to retard translation of said pinion member from operative position to retracted position.

, 1 9. In an engine starter: a power driven member; a pinion; having a threaded sleeve;. a threaded connection between the pinion sleeve and said power driven member whereby relative rotation between said parts effects translation of the pinion to and from any operative driving position; a brake band wrapped about thepinion sleeve; and means connected with the power driven member and maintaining the brake band in tension and frictionally engaged with said 20.'In an engine starter: a power driven'member; a pinion; a cylindrical member fixed with between the pinion and the power driven member whereby relative rotation between said parts effects translation of the pinion to and from an operative driving position; a centrifugally responsive member revoluble with the power driven member; a brake band having one end connected with the centrifugally responsive member and wrapped about the cylindrical member; and means connected'with'theoppositeend of the brake band for maintaining the brake band in tension and frictionally engaged with said cylindrical member. I

21. In an engine starter of the type wherein a pinion is automatically propelled to and from an operative driving position by relative rotation between a nut and screw: 2, power driven shaft on which the starter is mounted; centrifugally responsive means at all times rotatable with the shaft; and meansactuated by the centrifugally responsive means and operable to effect relative rotation; and centrifugally responsive" means rotation between the nut and screw in the direc- JOHN W. FITZ GERALD

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