US2640360A

US2640360A - Starter jaw advancing mechanism

Info

Publication number: US2640360A
Application number: US273961A
Authority: US
Inventors: Troeger Henry
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1952-02-28
Filing date: 1952-02-28
Publication date: 1953-06-02
Anticipated expiration: 1970-06-02

Description

June 2, 1953 TRQEGER 2,640,360

STARTER JAW ADVANCING MECHANISM Filed Feb. 28, 1952 INVENTOR. HEN/P)" TROEGER Patented June 2, 1953 rationofilielaware e Glai-msi;

presentinvention r Tat th en e starters and particularly 1:0 starter jaw a'tiv aficin'g'i mechi H1 engine starters some means are necessary to advance the starter j'aW- into engagement: with the engine aw upon emerge-amen of the starter: One method usec1?i'sa fi ie'tion n" eor itaet-witkr. the starter jaw to htfldtth jJ momentarily" against" rotat n toenablethe sdiew sham anda spline nutte' co'aet to mo've" He intki ng'a'g'e' ment Also, thefri'otion ri servest "diet the starter j aw in itsr etraeted pesinon we theen gin'eis running? This-' method ne'e numerous dis advantages, some of which are that firietion: means: alr present diii ifig' the operatien of the starter; th'e' fi -ititibii Be um-es wet and doesnothavasuinei fri'c rotation to: hold the aw its retracted por siti'ori' wh'e'ii the eng'ine is running. This is: especially a disadvantage when the: starter" is:- mounted'i with the jawse downward as is, required; in: many installations; 5150;. the? friction means do: not: periorm'v satisfactorily when low tempera turesiare encounteredt Itis: object; of my inventiorr to? provide a positive: jaw advancing mechanism incorporating positive holding; means: that: will; overcome the above diflicult-iesz- A positive holding means" pre=- vents rotation! of thestarter: jaw until: ithas moved: axially into engagement." The axiai move-*- ment of the screw shaft releases the holding;

meansto-permit rotation.-

Another object of; the invention is to: p'rovlde arrimproved s'tarteri Another. object.is toprovide =aniimproved starterfor operationatiow temperatures;

Another object: is" to provide an! improvetia amt. novel jaw adv-anoingrmeohanism 'for userin-engine starter-s.

Another object is; to providemeans for preventing the jawsfrom becoming. engaged byvibration when the engine is running, I

The above and other objectsand featuresgof the invention wi'11-. appear m'orefullyhereinafter" from. a. consideration of the following description taken in connection withthe-aocompanyingzdrawings whereinone en lfiodimentof: the invention isillust'rat'edby Way of example.

I'n'thedrawing; r

The single fig'u're isa seotionaiview' t an-engin'e' starter. embodying one form of: the invention'.

Referring" to" the drawing, the device therein shown comprises a starten assembly inclnding, in general, a motor I; having? a. driving. shaft 2! rotatablysupported By" a bearing 3 mounted in 2 end wan! 4 of motor housing 5. A pinion: 6}; shown; as integral with the aar-t 2 meshes with pIane't gene 7*. The planet gears T are" refit-'- any" supported by" ten bearings 3 mounted on stub" shafts 9* carried spider cage mi The' pIaEi'eiF- gear "elih' with a ring ear FF 51361 911 as' integr 3 1th gear" housing I 2 The gear housingi sharia I 35 and nuts M a'ssfli'owfi o'rb'y dt-he'i" suitable means;

Integrar with ti l' snieer' cage I l is pinion gear 5 aidafified t0 engage lanee gai's F6 W1 ha=1S enga e the li'n'g gear H ears" I 6 are supported by"bearmee 1 7 mountedoristub Shafi'fS-= nut- 2 1 thr'oug'h a torque. limiting dise pack 28;!

disc: pat-c1628 comprises a plurality ofi trio-'- tion dis'cs alternately" splined to" the inner face of; the barrel: and. the outer face oi thespline nut: 211m The discs of: the pack 2-8 are forced intofriotional engagement with-t each; other by a p'Ii1-- rality of-r oircumferenti'ally spaced springs: 2.9 compressed? between aflange; 341' on the barrel 25' and an adjustable nut 3ft threaded into the barrel 2& and set so thatthe disc pack 2 8 will slipat apredeterminedtorqum The" long; lead! internal threads. ofi the spline? nut 2-!- mesh with matinga threads of screw shaft 32 whiohisconne'cted to sta rter jaw Sfiaxiai splines- 34- for' rotation therewith:

The: starter jaw 33 is securedrto a; jawretainen 35 by air-flange 3-3 and snap ring 351 The out- Ward: travel of: the jaw retainer 35* is limited? by the flange 36' and the splines 34 on the screw shaft 32'; A spring: 3'8 compressed: between the jaw retainer 3 5 and a -spring retaining plate 3.9: biases the jaw 33 outward: A retaining; ring 40 maintainsthe plate 39 in position;

A featureofthe present invention resides in the novel meansfor. restraining the" jaw 33 against rotation to cause axial. movement t-l'ie'recif A- restraining member 41 is provided with: a conical surface; Argarter spring decent-tact? against the poniealvsurf-aoe 42- to urge a; splinedi portion 4% into engagement with the splineeflk on the starter jaw 33 that extend beyond the is secures? to the motor housing 5' by screw shaft 32. The garter spring 43 is positioned between

plates

45 and 46 which are secured to a bafile plate 41. The bafile plate 41 is clamped between mounting flange 48 on the housing l2 and engine mounting pad 49. Shallow grooves 50, which mate with the coils of the garter spring 43 on the plate 45 and conical surface 42 prevent the spring 43 from rotating. The restraining member 4| has a conical surface 5| which is tapered opposite to the conical surface 4|. Outward movement of the member 4| is limited by retaining ring 52 on the screw shaft 32 and retainin ring 53 on the member 4|.

An oil seal 54 is provided on the spline nut 21. Also, the spline nut 21 is provided with a spline nut cap 55 to prevent oil from entering the other part of the starter.

In operation, when the starter is unenergized, the contraction of the garter spring 43 exerts both a radial and axial pressure on the restraining member 4|. The axial pressure on the member 4| is transmitted through the screw shaft 32, spline nut cap 55, third stage planetary spider cage 24, second stage planetary spider l9 and first stage planetary spider cage H! to the fixed wall 4 thereby clamping these parts and tending to prevent their motion andv consequent possible damage due to impact caused by vibration.

When the starter is in operation, the clamping pressure, due to the garter spring reaction, is removed as will be explained later. The planetary spiders will be located radially by only the radial components of the gear tooth loads which will be free to equalize, thus avoiding the over-stressing of the gear teeth that occurs when the planetary spiders are rigidly supported by bearings which may not be perfectly concentric with the lines of action of the gear teeth.

Energizing the motor rotates the spline nut 21 through the planetary gear train and clutch pack 26. The restraining member 4| prevents the screw shaft 32 from rotating and axial movement is imparted thereto by the action of the helical splines connecting the screw shaft 32 to the spline nut 2'1. The screw shaft 32, upon advancing, urges the starter jaw 33 towards an extended position and also force the restraining member 4| further into the garter spring 43. The length of the conical surface 42 is so selected that when the jaw 33 has advanced a distance sufficient to insureengagement with a mating engine jaw (not shown) the member 4| will have advanced to a position where the spring 43 will be contracting on the conical surface 5|. The contraction of the spring 43 will cause a thrust to the left on the member 4| causing it to move on the screw shaft a distance equal to the space between the rings 52 and 53. This space is greater than the projection of the splines on the screw shaft and the splines on the member 4| no longer engage the splines on the screw shaft. The starter jaw will then be free to rotate.

The amount of taper of the two oppositely conical surfaces 42 and 5|, and the strength of the spring 43 may be varied to produce different backward and forward thrust. By making the taper of the conical surface 5| of less taper than the conical surface 42, a smaller force will be required to return the member 4| to its rotation blocking position than was required to move it out of the rotation blocking position.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangement of the parts may be made to suit requirements.

What is claimed is:

1. In an engine starter, an assembly comprising an axially stationary rotatable nut, a screw shaft splined to said nut for rotation with and axial movement relative thereto, a starter jaw member secured to said screw shaft for rotation and axial movement therewith, a restraining member movable from a position engaging said starter jaw to a disengaging position, spring means for normally biasing said restraining member in said engaging position, and means responsive to axial movement of said screw shaft to cause said spring means to bias said restraining member in said disengaging position.

2. In an engine starter, the combination of an assembly comprising an axially stationary rotatable spline nut, a screw shaft splined in said nut, a starter jaw member adapted for rotation with and axial movement relative to said screw shaft, a jaw retaining member, spring means interposed between said jaw retaining member and said screw shaft for urging said jaw member into engagement with an engine jaw upon axial movement of said screw shaft, a collar surrounding said jaw member and adapted for axial movement with and relative to said jaw member, spline means for connecting said collar to said jaw member, garter spring means for preventing rotation of said collar and for normally urging said spline means into engagement, and means including a conical surface on said collar for urging said spline means out of engagement upon a predetermined axial movement of said screw shaft.

3. For use in an engine starter having a housing, an assembly comprising an axially stationary rotatable spline nut, a screw shaft splined to said nut for rotation with and axial movement relative thereto, a starter jaw member secured to said 4. In an engine starter, the assembly comprising an axially stationary rotatable spline nut, a screw shaft splined to said nut for rotation with and axial movement-relative thereto, a starter jaw member splined to said screw shaft for rotation with and axial movement thereto, said jaw member having a splined portion normally extending beyond said screw shaft, a restraining member having opposing ramp portions and spline means for engaging the splined portion of said jaw member extending beyond said screw shaft, a spring member for normally coacting with one of said ramp portions for urging said spline means into engagement with the splined portion of said jaw member to prevent rotation of said screw ing an axially stationary rotatable splined nut, a

6 screw shaft splined to said nut for rotation with and axial movement relative thereto, a starter References Cited In the file of 191118 p e t jaw member secured to said screw shaft for ro- UNITED STATES PATENTS tation and. axial movement therewith, a restraining member having spline means to engage said 5 g g g st g i O 3: 1 starter jaw, a spring member for normally urge e c ing said restraining member into engagement FOREIGN PATENTS with said jaw, said sprin member being adapted Number Country Date to urge said restraining member out of engage- 468,456 France 24, 19.14

ment with said jaw in response to predetermined l0 axial movement of said screw shaft.

HENRY TROEGER.