US2366504A - Engine starter - Google Patents

Description

Jan. 2, 1945. J. w. m GERALD 2,366,504

ENGINE STARTER Filed Jun 19, 1943 2 Sheets-Sheet l l4 0 I 4 3.]. 1s

Deceased By F 1% FJ'WH Execufrv'x Jam. 2, 1945.

J. w. FITZ GERALD ENGINE STARTER Filed- June 19. 1943 2 Sheets-She s: 2

Patented Jan. 2, 1945 T236 5 p ENGINE STARTER I John W. Fitz,; Gerald, deceased, late of Milwaukee,1 v Wis., by Mary- C, Fitz Gerald, executrix, Mil-,

waukee, Wis., 'assignorto Briggs &Stratton Corporation, Milwaukee, Wis., a corporation of j This invention relates to engine starters of the so called automatictype wherein thepinion' is automatically propelledto and from mesh with. the-ring gear of an engine to be started; a w

v A 'copending application Serial No. 491,513,

filed June 19, 1943, describes the advantages of using a-stack of cupped-spring washers as the resilient driving connection through which torque is transmitted to the pinion of the starter."

The present invention employs the same type- 'ofresilient driving connection but has asits ob-' ject to so utilize the same that the application of the cranking load is cushioned solely by slippage in the driving connection. As a result the cushioning of the starting load is more easily controlled and predetermined as only one" factor:

namely slippage in the driving connection per se must be taken into account. However, endwise resiliency is still retained to accommodate misalignment of the pinionand ringgear duringthe meshing operation. 4

It is, therefore, a specifioobjeot of this inven tion to provide an engine starter wherein. the

resilient drivingconnection through which. torque is transmitted to the pinion consists of a slipping; disc coupling orclutch having endwise resiliency inherent therein,

With the above and other objects in view which will appear as the description proceeds, this in-' vention resides in the novel construction, com, bination and arrangement of. parts substantiallyv as hereinafter described, and more particularly definedby the appended claims, it being understood that such changes in the precise embodis ment of. the hereindisclosed invention may be madeas come within the scope of the claims.

The accompanying drawings illustrate two complete examples of the physical. embodiment-of the invention constructed in accordance with the best modes so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a view in side elevation with parts thereof in section of an engine starter embodying this invention, said view showing the pinion in its normal retracted position; t

Figure 2 is a view similar to Figure 1 but showing the parts in the positions they assume in the event of improper meshing, that is, end-to-end abutment of the pinion and ring gear teeth;

Figure 3 is a, view similar to Figure 1 showing the pinion fully meshed;

Figure 4 is a perspective view of a part of the pinion hub and illustrating the mannerin which the pinion stop in that form of the invention S-O I E 1Applicationdune 2'19, 1943;1seiiariwb;491,514I

' 4Claims'.

(Chis- 7), 1 n a n, a r t Figure .5 is a view similar to Figure 1 illustrating the application of this invention toa starter embodying the conventional type of. pinionstop.

Referring now more particularly to the accompanying drawings, in which like numerals indicate likeparts, the numeral 5 designates the shaft of a, starter motor upon which the starter indicated generally by the numeral'B is mounted.

The starter comprisesqa pinion Twmovable along 1 the shaft into and out of mesh withthe ring gear 8 o'f ian engine to'be started; and means for actuating and driving the pinion. 1 r i The pinion 1 has ahub 9 internally threaded as at In to receive the threaded portion III of anactuator l2.:,;Theractuator l2 consists of a tube the outer portion of which has the external threads II and gtheinner portion of which has a smooth; cylindrical surface l3 of a diameter substantially equal to or at; leastnot, greater than the root diameter of its threaded portion, I I. It

is freely slidable and rotatable on the motor shaft and is drivingly connectedv with the shaft through 5 This driving connection comprisesa flangel5 on the, actuator, a drivehead:,l-iifixed to the motor shaft, and a stack of alternately arranged cupped spring Washers l1 confined between the,:

flange l5 andthe drive heads Ashell l 8 attached to the flange I5 and engagedover a flange on the drive head holds these parts against separation and-maintains the stack of spring washers under a degree of compression. l g

By virtue of the endwise pressure on the stack of cupped spring washers they engage at their inner and, outer peripheral portions with sufiicient friction to provide for the initial transmission of torque from thedrive shaft to the actua tor to propelthe pinion to its operative driving position shown in Figure 3 and defined by a pinion stop indicated generally by" the numeral IS.

The pinion stop I9 contrary to customary practice is between the hub of; the pinion and the actuatorso that in picking up the cranking load :5; there isnoincrease of the endwise pressure on the stack of cupped spring washers. Consequently, the cushioning of the application of the cranking load to the starter is obtained solely by the frictionally resisted slippage between the spring washers of the driving connection;

However, in the event of tooth abutment as shown in Figure 2 the endwise resiliency of the stack of spring washers provides the desired cushion and accommodates such misalignment.

shown in Figures 1, 2 and 3 is constructed; and The P n t I9 is f WW1 a d Si p e c nan impositive endwise, resilient driving connection struction. It consists of a slab 20 off the end of the pinion hub secured back on the hub but in a position revolved several degrees from its original position so that the teeth thereof are misaligned with the teeth of the hub. In this manner the teeth of the slab form abutments across the ends of thespaces ofithe hub to; collide with; the ends of the teeth II on theactuator.

To hold the slab 20 in this position its outer peripheral portion is notched to provide lug 22!? and spaces 22 and the end of the pinion hubis similarly notched to provide complementary lugs 2| and spaces 22; and a spring ring- 23 s'napped into a groove 24 on the lugs 21"" of the pinion-hub holds the slab assembled withthehub.

spaces therebetween; and means for securing the short length of internally threaded pinion hub to said end portion of the pinion hub with its lugs in the notches of the pinionhub and with the threads of said short length of pinion hub disaligned with the threads of the pinion hub portion so as; to provide; abutmentsr engageable with the ends of the threads on the actuator.

3. In an engine starter having a pinion, an

actuator, a screw threaded connection between the" pinion and the actuator whereby relative rotation therebetween effects endwise movement of one with respect to the other to propel the pinion into andoutof mesh with the ring gear of an It is, of course, also possible to use the conventional form of pinion stop collar as shown in Figure 5. Here the actuator has a smooth. sunfaced extension 25 projecting through thepinion.

and the stop collar 26 is secured on the outer end thereof in a position to be engaged; by thexpinion when: fully meshed with ther-ing gean.

a From the foregoing: description taken in; con.-

. nection with the accompanying: drawings;. it will to more accuratelycontrol: the cushioning; efiecth What is claimed'as the inventionx is: I 1. In an engine starter: a pinion having: an. internally threadedhubportion; a pinion-actuator having a hub the outer end portion oiwhich.

is externally threaded and threadedly engaged? in the hub of the pinion and the inner portion. of which is smooth surfaced and of. a diameter: no greater than the root: diameter of its threadedi outer end portion: and a pinion stop for limiting:

endwise movement of the pinion outwardly oi the actuator comprising a collar having: internal. threads similar to those of the pinion hub and? fixed to the end of saidpinion-hub: in a position angularly onset with respect- {id-the threads: thereof to provide al mtments across the ends: or the" spaces of the internal threads or the pinion hulo portion to course withthe add-scent ends of the threadson the actuator. g

2-. In an engine starter: a pinion-having. an in ternally threaded hub portion: a pinion actuator having a hub the outer end portion ofwhichis: externally threaded and threadedly engaged in the'hub of the pinion and an inner portion of which is smooth surfaced and of a diameterno reater than the root diameter of its threaded outer end portion; anda pinion stop for limiting endwise movement of thepinion outwardly of the actuator comprising arelatively short length of the internally threaded pinion hubhaving its outer periphery notched to provide lugs and spaces therebetween, the end portion of the pinion hub remote'from the pinion" being similarly notched to provide complementary lugs and- Deceased.

engine to be started, and having a driving head: an impositive endwise resilient driving connection between the driving head and the actuator I comprising, aplurality of cupped spring washers confined under a degree of compression between the driving head and the actuator sufficient to establish. an. initial. torque: transmitting connection: from: the driving. head to: the: adlacent; washer and through the stack: of.- washersttoythea actuator solely' through. frictional. engagement; means engaging one peripheral edge: ofxallr of the washers.- for holding; them axially aligned, the: other peripheral edge; of all; of the: washers being; entirelyfree for: radial movement. in. or ..out...as-; endwise pressure onthe stack: 0t washers varies;

and a pinion. stop for" limitingyadvanceot the pinion so thatthe: torque impositively transmitted; .150": the: actuator by the, friction :between; adiw: cent spring washers is applied toithje pinion 4 In an. engine starterhaving a pinion. and a;

pinion actuator with. a :threaded connection-e.

th'erebetween' so: that. relative rotation of said; parts 'eflfectstranslation of the pinion toward; amt.

from its operative driving positionrarr imposi tive endwise resilient driving connection for. the

actuator: comprising, a driving; head. adapted to be fixed to. a power shaft to provide a: fixedldri e. ing: abutment, anabutment; on the actuator a plurality of. cupped: spring; washers assembled 911-; tern-ately in astack between said. abutments on.

-". the actuator anddriving..head;;1neans engaging;

endwise pressure so: asitol providegan'jendwise re silienttslip coupling, operable through frictionzbea.

tween adjacent.- washcrsand. between. the end. washers and said abutments; to eiiE-eotinitial torquertransmission. from; the driving headto; the

actuator; and a pinionrstopfor; l-im rtingradvance.

of the pinion so thatthe: torque impositiveld transmitted to the actuator by the: friction between. adjacent spring: washers is appliectpto "the; pinion.

MARY 0,. 'GIERALD Eaxecutrilr of the Estate of, John W. Fitz: Gemld.,

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