US1232482A - Tractor. - Google Patents

Description

C. L BEST.

mama.

APPLICATION FILED APR- 6.1914- 1 @32 82D Patented Jul 3 10, 1917.

5 SHEEISLSHEET I.

w/r/vassss; l/Vl/ENTOR Q y I U5: gywfi ATTORNEY C. L. BEST.

mom.

APPLICATION FILED APR. 5. $914 1 3,2 1 Patented July 10, 1917.

5 SHEETS-SHEET 2- mg. 5..

C, L. BEST TRACTOR.

APPLICATION FILED APR. 6, m4.

' lfia fiaa Patented Jul 10, 1917.

5 SH EETSSHEET 3.

WITNESSES:

C. L. BEST.

TRACTOR.

APPLICATION FILED AWL-6,1914.

LQMASQQ Patented July 10, 1917.

5 SHEETS-SHEET 4.

WITNESSES: I/VI/E/VTOR WQQQOW By ATTOR/i/EY C. L. BEST.

TRACTOR.

APPLICATION FILED APR.6,1914.

1,282,482 Patented Jul ,1917.

Big. 6.

5 SHEETS- T 5- 11V l/E/V TOR WITNESSES: v V

M v mug/0pm ATTORNEY To all it may/concern v .tBe ityknown that I, C ARENCE 'Lno BEST,

:f new and useful Improvements in Tractors,

CLARENCE LEoBnsrr, or ELMHURST, CALIFORNIA."

. TRACTOR. I

citizen of the United States, residing. at

Elmhurst, in the county-of Alameda and j State of California, have inventedfcertain of which the following is a specification This invention relates to t "general class- Y the rail vtype, or

" and'farrn use.

this new type of tractor introduce problems cessi'ties;- 1(2); varying texture oft ract1on surface -(3)ysurface' contour conditions-1nv relation to steering; (4:) pract cally proof traction engines. -At the present time there a're in practice two types of tractors locomotive, and the 'road type, or tractionen'gine; both of these forms. are designed te lates-toa new form of traction device,-a

faces and tilled ground in its" varieties,'jas

met with under all conditions of cultivation 1 The j-conditions of operationfconfronting practically. non-existent in connection' with rail'orroad engines, na1nely:' (1) soil neliibitive wear and b'reakage. 'Hereto'fore the efforts of lnventors 1n the tractor art have beenidi rected'to'the' probj lemof producing tractlon'engines spec1fi,-

cally designed for road'servloe to be incidentally'used for tillage when favorable conditions permit.

The present invention v is designed specifi cally"for."farm traction wlth primary regard and reference to I soil' necessities for In'v'iew'of the departure, from accepted pract ce in the present invention and the and a properlunderstandiiig of the significance of the various mechanisms hereinafter In brief the problems solved and the 'ob,

combinations of devices her i aft d scribedrelatetoqfi' soil," thesef maybegrouped.under the 1m:

Specification of Letters iatent.

operate upon; artificially "prepared roads. The present lIlVGIltlOIl 're- ;natural' ground surface type, or agricultural Y ftraetor primarily designed to operate uponl rough,-huinmocky, sandy, a t ve v "work'under present day condltions. Y 1 f-Th'ej' first problem which confronts the {builder of a road" tractor has relation to the character of the'surfaceupon which has :to travel. The firstprobl'em, which ong f 1-) The a ricultural necessities, of the;

ama Jul to, fear.

. ApplicaticmfiledApril 6, 1914. Serial No. 829,848..

avoidable requirement of-light weight of the structure, or its equivalent; small pressure per square inch of soil surface;

; (2)'Tracti0n under agricultural-surface conditions involved in traveling over plowed or ha'rrowed ground, friable ;or.sandy soil,

checked or ditched. ground, wet or swampy ground, and otherwise unfavorable traction" (3 Undulating humrnocky 3 and rough contour conditions, includin .thoseproblems relating to flexibility-where y both traction surfaces;

contact and guiding contact -is maintained at all times regardless ofthe unevenness of.

the ground;

.-.(4C) Upkeep, wear and and breakl age expense under the extremely adverse. re-

qulrements confronting a tractor for farm fronts the inventorof anqagricultural trac- 'sities' of. the soil.

' tor, has relation to the-agricultural 'neces- Upon an basic diversit in: problem'f'and funct' n rests "an essential" ifierence between a roa eng1ne,and' an agricultural tractor,

and upon the clear perception of thisdi versity in concept of end or object-"sought I rests, the novel construction disclosed in the present lnventlon. Th is concept ofendand its physical realization in practice ."is for the first time hereinafterdisclosed;

The railway locomotive is l uilt'in-accordance with the fact" that it is intended to run upon parallel and'practically straight metalli'crails. The road engineis built to travel upon the hard, smooth macadam of the high- ,way. So ,long' asv the locomotive remains upon the track and theroad engine upon the highway, tractive problems are practically to meet these specific conditions. a

The first'requirement of an agricultural 'solvedbvfhe normal construct-ions arranged tractor in-order to successfully efiect'its ulti-- mate purpose 'ofground'zcultivati'on is that it must be-so constructed as to permit of its ,9 traveling.over soilintproper condition of, --tilth'a nd not erush' eggs buried three inches beneath the surface of the loose top soil. I If-, atfvariable"-and'frequent intervals, the: rails-are removed from a vroad-bed and a. locomotive "j compelled to travel upon the' ties, at once conditions are introduced which i render the construction ofthe engine useless and abortive. So too with the road'engine;

if the roadway is crossed by areas of sandy for loose soil sown with eggs which must not be broken, plowed land which must not be packed, and byhummocky ground substantially the samejdifficulties would face the for smooth hard macadam road service. The

5 (after afashion and most inefliciently) upon fact that the locomotive could progress macadam roads, and the road engine in like manner upon, more or less, uneven surface,

' does not change the essential character and adaption of the two devices, 'nor their un derlying concepts.

Practically speaking there is, this artprior to the present inventionbut one form of traction producing support, namely :"the

wheel. Much effort has been expended in other directions, as'forexample the walking type in all its grotesque and futile shapes,

v and the track layer or caterpillar traction:-

chain. v

In. their varied forms, the problemsfisolved by the present invention are those which confront both the round'wheel as well as those :which are peculiar to the track-laying-type of tractors and others notencounter'ed upon artificially prepared roads.

r {Notwithstanding the fact, that thetrack- I laying engine is probably as old as theordinary, roundewheel 1 road engines, and certainly as 'old as its' practical commercial utilization, the cheapness,,itstrength, s1mpliCi y'a-nd reliabilityojfthe round traction wheel has caused this form oftraction driver to assume the position of an accepted stand ard, while the cost, inherent weakness, comp'li c'ations and liability "to breakage, wear and dis-arrangement of the caterpillar endless traction+chain has relegated this form,

"more or less, into" the ;category of freak v cal results.

devices inithetra ction engine, art.-

. Certain inherently valuable characteristics of the track-laying tractor havefrom time to timeincited efforts to overcome its'seemare seemingly inherent in this form of tractor and relateto certain maln caus'es: 1st,

the great. multiplication of lubricant'need-' ing axles or pins necessitated by the chain joints and their location close to the traction surface as distinguished from the Wheel axle of the ordinary round wheel tractor high above the ground; 2nd the large two dime'nand moreexaggerated sional traction contact surface, 8., the length and width of the chain track in contact with the ground -as distinguished from .the line contact of the roundtraction wheel- After traction the-next set of 'problems to be solved has to do with control of direction of travel. In the locomotive this difliculty is avoided and made substantially .non-ex-f istent by the presence of tracks and involvesmerely flexibility of wheel-base to accommo date curvature' in the tracks. ,VVith the round wheel-road engine also this problem is comparatively simple, due to the fact that the round wheel makes but line contact with a plane surface. The problem of steering in connection with the caterpillar tractor presents an altogether different aspect. On the face of it, there is presented a seeming impossibility, and one which heretofore has been a practically insuperable problem. This will be appreciated when the endless traveling chain character of its tractor device is considered. A round wheel traction engine is supported upon two longitudinally disposed supports, the driving wheels and the steering wheel or wheels. If now a thirdv supporting and driving Wheel be introduced between these supports, as the idler track wheel in the ordinary track-laying tractor,

it is obvious that this third wheel renders the device if not practically inoperative, at least very diflicult to steer and subject to highly destructive strains upon uneven or hummocky ground. For, atQevery hummock, the steering wheels or the driving wheels will be raised out of contactv with the "ground.

.This is the present situation and problemof the caterpillar tractor, so far as concerns its capability to travel and steer on rough or hummockyzground, andadded thereto is the practical incapability to work in loose soils or sandy or gritty surfaces on account of the multiplicity of lubrication needing 7 joints in its traction chain.

To give a' proper understanding of these various diificulties and problems and of the mechanical solution hereinafter set forth, it

is necessary to recall briefly the developments in and the conditions surrounding power cultivation during the past twenty years and up to the present time in the far western portions of the United States, for ingly insuperable mechanical difiiculties, by j optimistic and. courageous mechanics with, heretofore, only very unsatisfactory practi-v The reason'for these failures it is to meet the requirements thus disclosed which'is the ultimate object of the herein orhorses, a machine of 60 H. P. or more was necessary for at that tune it was possible to J getbut40% at the draw-bar, or 50%-say.

from. five to ten years ago. This steam tractionengine of 60 H. P., or more, weighed -;tion.fdf fuel. oil these inachines@weref largely and formed what: is commonly lmo'w'n as which the groundisj-plowed, This .5ploW-" I the rain ir'Om, sinking deeply, he'ncehin the evaporated, leaving the plowed land dryl f;tractor vith-itsv 24inch face wheelsicould. v

" not goon this land to h'arrow it until the 1 v lands and exertingless than round wheel 20' itwas capableof on dry ground; a- -Runni'ngv To; overcome it :became necessary to b could not' {make a 8110a; enough comer in 1 Structurei Theniit' required skilled opera- 6 5 down-deep; after the rainthese'maf from 15 to 25 tons; With this engine it Was.

necessary tohave a water wagon, four 7 I I was moist. If'the ground waswet on top,

horses and 'aj ma'n, anengineer, firemanandj a PIoW manH wUponthepractical applica 9 made over into oil-"burnersfon account tot i beingfsaferin the harvest field: The cost of running? one ofxthese ina'chineswas approxi-- mately -$30,00 ;per-day; and it would plow' 10 ordinaryiplow-abl'e farm landatthe'cost ofaboutY$10O per acre.- It was found thatthedriveiiwheels' must be of at least-2i-in ches p v t0 produce-a machin'eo'f this class." He built 'vfor'the market all steel machines with the 'Wide and-somei8gfeet' in diameten. With this width the'y' 'couldgo on some farm land and 15 do good work. But-if, as is frequentl-ythe'. 'case, there was-a-sandyfstreak, through the 'field it"wa's necessary to uncouple en- -gines from their plows, run across. this" streak,-'drop a chain or cable behind and run '20 the plow through, which, of course','c'u t down I the number of acresfper day and increased "expenses; v f; I

'- WYith these engines the pressure per square inch was, so great that it -,packed theland plow panj; about inches from the topof "the: ground, this being the usual depth tov pan being packed har'd'an'd solid prevents hot western] summer this moisturegis fsoon' When foggy or cloudy aft'er'j the rain; this mo'isture'l1 had evaporated; For, "if the plowed groundwas; at all moist,jifi inclined to stick. on the wheels, :the tractor: would v slip and do-only a small-percentage; of; what :this 'heavy. tractor with its narrow wheels over the plowed ground isopa'cked the soil-Q;

I that it very seriously-lessened'the crop of gr i w d H M make the. wheel's wider, {and vWider until we have gotten them up as high 'a'slfi feet wide on the side. Then the n1achine-:'Was too wide,"- clum'sy" and awkward to. handle; It

turning. The 1 additional; weight of (th To 0 5 big wheels consumed a lot' of powea 'jsetIthis-builders added more p'owe s'which,

5 meantheavi'ergearing and-heavienparts oftors,- whichin turnfincr'ea'sed the cost-of operation, more fuel, whichiagain: increased:

tion wasthe fac t' that these machines packedjjf v v Mountains there' is hardlyaranch that does not have asw'anlpy' place. or a creek. running- 130 the ground and the .mnst'urei couldnot get chines could .not goon the land for th packedthe ground worse than ever when it} .erate; hence the introduction ofthe roundwheel internal combustion tr'actozz.

The present inventor was-0116M the first I mainidea of-redueing the weight'and get ting the ,machines'seemin'gly ridiculously strong." But,.-even with the gas round wheel tractor, which weighed but half as much as the steam'tractor with the same amount of power, the-old objection of packing the soil p remained; .hence, wider'wheels. were put on the gas tractor as muchas 12 feet wide on theside making once more a'machine awk-fl ward' 'and clumsy to.- handle and excessively eep.

wasteful of 1powerand of cost of construc- '90' 'tion- ,an'd up I [reduced the-cost ofcultivation the packing Though this gas tractor ofthe land reduced the yield more-and more -eyery 'year, for a hard pan developed at the 1depthtoWhich the ground Was plowed. I

It is y expensive to' SllbySOll land; it is ou't Of'the question to doitfrequently So :thejproblem' now pressing for solution is :1

aniagricultural tractor capable .of operating: successfully upon all character of farm prfii l Ie upon the surface; so slight indeed not unduly compress the ground to the-J- depth at whichthe eggs are buried;

'The selfi laying track engine, having'an endless traveling platform, consisting-of a chain with broad shoes or cleatson the'face of it; suggests favorablepossibilities in this direction. So there have been numerous at- '1 temptsmade to produce such an engindwithbut .very imperfect'andineflicientresults. It has been found that in these tractors the wear and tear on the nnlltitude. of hingepinsl'in the chain'is too; feat. 'Besidesinu; going over rough or uneven ground,th'ey-.

"lack flexibility; To overcoine'both these ob-i 12'0 jectio'ns looks like an impossible taskJi":

Banchershavegotten to'the point where.

it is. unprofitable to farm with mules or" horses onaccount of high cost of feed and; niens wages,- and they cannot "permit their-n25 land to bepackedwith the round wheel-ma}.

chine.

In the co htry l yingfw st of theTBoEkj V through it, which means a bed of sand or Italso produces wear and friction at this.

rough rocky places. 'Going across checks or little mounds, track-laying tractors prior to the present invention, (for the reasons already'stated) rearup in front, with the result that besides the steering difficulty, this de'structively jars the construction and causes an impracticable amount of breakage. The endless traveling platform consisting of links with a pin put through their ends as constructed prior to the presentinvention results in impractical power losses.

point so great that new tracks have to be put on in some places as oftenas every three or four months ata cost of from $400.00 to $5 000; and even sotheir range of operation 'is r'cstricted by sandy. or gritty soils. And this terrible expense must be borne to avoid packing the land.

upkeep expense would not beat the mule in cost per acre, they have continued in use where conditions are favorable because feed and man hire is getting ever scarc'er and higher. In many places men cannot be gotten at any practical price.

The caterpillar machine, when conditions are favorable for its'employment, can accomplish one object, namely: that the pres sure per square inch is light, yet as heretofore constructed it has objections worse than the round wheel, for it cannot go over checks or hurmnocks. To go over such ground jars it to an extent that it breaks down and the wear on the chain track pins consumes such excessive amount of power as to. make it in most cases too expenslve for practical use.

Its efficiency is also less than the round wheeler when the landis in condition for the round wheeler to run.

Thus it is seen that to Z bine elements to provide: (a) tractive power omy and cheapness of construction.

It is the object of the present invention to provide'simple cheap and effective de vices to meet the requirements of each of these sets of problems andof such character that these devices combine and co-act with each'other to produce the unitary result of meeting successfully the necessities of farmwork and produce a practical and in practice successful all round agricultural tractor, an object not heretofore accomplished.

This desirable object has been accomplished in-the present'invention by means While it is found that this machine with its heavy be practically Op? erative an agricultural tractor must com of the hereinafter described devices mechanisms-reference being bad to the accompanying drawings in which? I Figure 1 is a plan view showing the rela-' tion of the radius tractor trucks. i

- Fig. 2 isa side view showing plvotal attachmen-t oftractor truck. I 4

Fig. 3' shows a detail of a portion of the endless traction chain. on a larger scale partly insection.

Fig. 4 shows the construction ,of Fig.3 in

el ovation and partly in section, the relative position of the chain guidebeing shown dotted lines.

Fig. 5 shows a detail upon an enlarged scale, of the endless traction chain and tread plates with antifriction guide in "vertical section.

Fig. 6 shows an elongated modification :of i i the antifriction ball race the cover being broken for clearness of illustration.

Fig. 7 shows a transverse sectional eleva-. I

tion of Fig. 6.

Fig. 8 shows .uponan enlarged scale the arrangement of the engine and starting device.

Figs. 9 and the device traveling on hummockyground 10 are diagrammatic views of showing the constant support of'and'by the 1 is a'frame upon which is supported suitable motor devices shown in the drawings as an internal combustion motor 2. Near the rear end of frame 1 and transversely theretois'a drivingshaft 3 suitably connected to the motor 2 to be driven thereby. -I makethis shaft3 in two parts connected and driven by suitable difierential gears of ordinary form to permit ofindependent motion in each part, as shown in the diagrams Figs. 9

and,10. This construction is indicated by thegdifferential' gear case 4 in which the shaft is suita'bly j ournaled. The shaft 3. and

its gear case l are suitablyv secured to the frame 1. It -is shown as lying transversely across. the frame 1 passing through the differential-gear case 1 which latter is secured solidly to the frame 1.- Upon each end of the dividedshaft 3 which projects beyond the frame is secured a driving and supporting sprocket w heel "5, which two sprocket wheels 5,- 5, with a front steering" support base for constitute athree wheeled or tripod the motor supporting frame.

A radius tractor truck 6 extends alongeach side of each wheel 5 and frame as shown in Fig. 1. The side members of tractor truck 6 extend beyond the axis of sprocket wheel 5 and in. the spacethus provided and between its sides is an idler wheel 7 a The idler wheel is journaledin boxes 7 one upon l ltruckfi These" journaliboxes areprefer a suitablelelectric motor 19. The shaftas' shown by the adjustment screw B. f-Thetwo sidesof the tractor truck "'joiiledlatanysuitable place along their len'gth, shown in Fig. 1 asafstrnt located'at each' end.. 'Aj'bracket 9 rigidly secured'to the frame 1' 'extendstransversely above} the truck 6. 'Be'tween this' bracket andtractor [ably slidable and providedl with suitable meajns to'efiect 'their adjustment with referenfceto the'truck on which they are mounted, 1

6. are

truck 'afspring 10 is proyided -forming .a' resilient-i cushion between thetruck 6 and bracket?! Extending aroundand en aging the sprocket-wheel 5' and idler-wheel endless traction chain 11 of peculiar 0011- s truc'tioni (which will be .n'iore particularly "cI-Iltural:conditions; .20

described later)- .espeeiallynadapted to agrine ther .the max-is "tractor ducks 6; '6 is *journaled at one endfi' pon shaft 3', the other I end ofithe'truck being free.to swingina verti'cal-a'rciwith the-center of shaft 3 as its axis ffmgc oti mjn order to automatically,

independently, and 'i'esiliently accommodate v itself-to yarying ground contours without thereby bending, kinking orothelagwis'eIaf-- Y 1' fecting the working I tension of the itraction 1 chain substantiallyfas shown in Figi rand Fig. 2 and in diagrammatic Views Fig; 9 and Fig. i '10, "thus makingthe sprocket whe'els '5.

v5. With a forward steering support%in' to tripod base"' fi'x ed relati-yely to the Varying position of, the" tractor trucks, in their autoe matic motions accommodating themselves top the p'lane'of its' longitudinalcenter-"unoppothev uneven or' ground surface' Intermediate ofjthe wheels..5,-3 1 d 7 isan antifriction chain guide. 12 secured to the truck-6 and betweenjitand-the lower,-

I 7 {and consequentlystationary'with reference trucks 6. 6." 1

or traction fold 50f the chain; 411' being. thusmovable with referencefto the :frame l but stationary with reference to a line joining isan' also connected with the drivingjshaft 20. of.

the motor 2 byisuitable mechanical Tfconnec connection is shown in the present instance as chain sprocket-'21 upon shaft 20 and chain pinion 22 .upo nshaft 18 and chain belt connecting ,the'two spr'ocket-yg heelsand 22 infdrivin'g association.

' nected by a bolt-11 and also by tread plates l lvwiththeir holding bolts 11?--subs'tantially as shown in the yiewsfreferred to and also in Figs. 5, 6 and? To this extent the parts link chain.

constltut e a link chain not-essentially differng fronij 'anj ordinary-two sidelmembered qThe chain ll-heretofore" referred to is eonstructed a shown-in the details Fig.3 and" Fig.4 to consist of .side plates 11 ''1l .con-

To meet/"and providetor thepeculiarly:-

= exacting conditions, (not e lsewh er; e met.-

tr n chains in agriculturalitram tor serv'iceg a radical departure-intractor chain) construction is introducedjin -the means employedof'hinging the links, (made as already;describedytofeach.lother. Be-

tween thesideplates 11 ,11? isfp'rovided at one end; a'; fulcrumicas'e'11 rigidly secured-at j each ofjitsendsto theside membersby any;

suitable. means;- 'Interiorly of case-"11 is 1 provided'a longitudinally ex'tendi-ngradially '])I "ojecting rib brffulcrumll? extending to 'the aXis-of the cascgThe inner surface of rib or fulcrum 115 is beveled radially from site sides of. its central plane thus forming the outer end of-this fulcrum into an obtuse angle, whose apexj is the} axis of the" case.

Between the sides 11 11 at theopposite endeof case '11 isproyided a SUI-711131.18 of less the centers of thefsprocket wheel 5 andfi'd1er..

to the normal path of; the 'chain'- '1 his' anti-' to the lower'foldo --jthe chain- "depress it slightly asshowni-in Fig. 2 oi; to p 9 and 10.

shown in the present instance as a worm and pinion and rearwardlyextending shaft; 14 with hand wheel 15. Thissteerin'gsupport with sprocket=wheels 5.j constitute a con stant tripod support for motor 'framel independent of the movable radius tractor Associated with the-motor2 isa radiator 16 provided with a cooling fan 17 secured upon a shaft 18 said shaft idlrectly connected with and being the armature shaft of.

r ermit of the chain." being straight between'the peripheries of the wheels as indicated in Figs.

At the forward end *of'frame 1 .is'located a steering and supportingwwheel 13' provided with .a suitable operating attachment aplane extending longitudinally of the strutalong its axistorock orsee-saw on-the fulcrum; This strut is'frigi dly1secured atieach of-its' ends to the side vn'lenib'ers-11 l'l with its working plane -11. .'set' at an angle with thelongitud-mally horizontal "plane of the hinge axes of the said members. This angle preferably corresponds to one of the angular surfacesof fulcrum I11 ofcase 11f tolie in workingcontaot therewith'when the assembledehain is inworkingposition, and rock or -oscillate thereon"when-the chain is flexed.

,ThB jcase' of'the side members 11 11 have an" inward onset and the strut end of the" same members have a corresponding through its. ;.doacting hingedtoget er by each strut 11 fulcrum case.

' The'treadplates11 of the links and chain thus described, extend. somewhat beyond theoiltwardi;, ofij' set, so that the-links consistmg of Pas n hinge axis of the links of adjacent treads tion of the traction chain' just described though not so urgently in the. case of the 'chain) is preferably made to avoid sliding frictional contact of working surfaces. In other words tore'move 'the necessity of lubrication in these parts and the condition which has in the past rendered the. renewal of the chain parts a practically prohibitive expense in track laying tractors when applied to agriculture. For this reason the antifriction chain guide in one of its forms consists of a hollow drum 12- in contact with the upper surface of the lower fold of chain 11a pair of ball races 12 12 one adjacent to each end of the drum 12 Each race is provided with balls 12*- or other antifriction devices. The ball track is preferably arranged as shown to provide anti.- friction abutment for the roller 12 against upward andlateral movement. And in ad dition thereto the race 12 and 12 and balls guide for chain 11.

12 may be so disposed as shown in Fig. 5 to form lateral antifriction abutment and In the modification Shown in Fig. 6, the ball race is made elongated to this. modification also the roller or drum may be omitted entirely the balls serving as lateral and vertical abutments and guides as shown in Fig. 7.

By the herein described mechanism elements are combined which meet and provide for the previously stated conditions of agricultural tractor service, and combined mechanisms which have successfully withstood the test of actual practice (a) The tractor chain support furnishes power. means ,of less than round wheel ground surface pressure per square inch and .will travel' in working practice over soil in good tilth without breaking eggs placed a short distance below the surface.

. (7;? The tractive chain means is practically una e cted by sand and grit by the substitution therein of rolling contact for sliding frictional contact surfaces. That is to say,

' the substitution in the joints of the-chains and attachments of rolling contact between the adjacent coacting surfaces. By this substitution need for lubrication is avoided and necessity of excluding sand and grit from the coacting surfaces working close to the ground. By this substitution also the I abnormal and commercially prohibitory wear and breaka e expense is practically ellmmated and re uced to ordinary machme wear of favorable condltlons.

(-0) The tractive power per unit of weight is greatly increased by the elimination of the excessive waste heretofore a necessary accompaniment of the sliding fractional character of the numerous chain joints necessary in the track laying type of tractor device.

(d) A tripod base and yielding support between the steering and traction wheels is provided for by the freely pivotal attachment of each resilient ended traction truck upon the axis of its traction wheel. The. two-part driving shafts permits of the independent rise and fallof each truck without kinking 'or changing the working tension of the traction chain as is illustrated in Figs. 9 and 10. By this arrange ment hummocks or ditches may be encountered and traversed without affecting the steering wheel contact with the ground and consequently without affecting the tractive effect or the steering capabilityof thetracs tor upon the roughened surfaces.

(e) Cheapness and simplicity-of construction, economy of operation are brought about and provided by the construction of the traction chain and traction chain antifriction guide, in which, owing to the substitution of rolling for sliding contact in certain working parts, cheap unmachined castings can be and havebeen substituted for expensive machine parts. The elimination of machine work which has heretofore made the chains so highly expensive a con-. struction, besides bringing about a great re duction of first cost, adds greatly to the inherent strength and effective life of the chain byv using the naturally hard chilled skin of the cast parts to be effectively utilized to resist normal wear of the rolling surfaces. Abnormal or unnecessary kinks and strains upon and consequent breakage of the chain are avoided by the stationary relation of the chain guide to the normal pathof the chain between the peripheries of the driving sprocket wheel and its coacting idler wheel. "Simplicity, economy and cheapness is also provided by the direct driving ofthe radiator fan upon the shaft of a dynamo as this latter may be and is employed .by suitable devices to act as a starter for the tractor motor, a matter of high consequence and importance.

In view of the many and radical departures in the present invention from the nor mal practice and the important results secured thereby, Ido not desire to confine myself to the particular forms, arrangements or details of construction herein set forth to illustrate my invention and. I claim this invention broadly and all modifications thereof such as may be madeft'o-adapt the invention to particular uses of conditions of operation without departing from the spirit of the invention.-

What I' claim is:

1. In, a tractor, and in combination a main frame, a tractor truck mechanism comnrising' a; driving. sproeket wheel, truck I frzime pivotally-mounted concentric with the axis, of the driving sprocket-wheel, a; trac-' tor chain, a curved idlerv "surface andtfa;

spring member normally tension'edi'for load carrying service and positioned at=the rear of the said driving-sprocket wheel. 2. In; a tractor, and in combination a main frame "aft'zacter trunk mechanism co driving-sprocket. wheel, a, truck-.-

I frame pivotzilly moiinted concentrie with ,tractor chain,' a eurvled' -idler surface,. einti" an. springzinember normally positioned :ebbVe' 5.

i I end of the truck frame the axis .of the drivingflsprpcket wheel, a;

the plane of the truck frame for resisting;

.3. In t tractor, "and combi-netiom' at fma'in frame,' a trector truck meohanismeom- 'prising at" driving sprocket jwheel', "a truck 7 frame pivotaily mountedconcentric with the 'axis ofthe sprocket wheel, e'traetor chain,- e f curved idler s'firfa'ce, and spring mechae nismto resist upwardtilting;movementof the forward end ;of the tractorl.tru'ok,.'said,

; spr-ing"mechanism being-of, a length sub- *stantially vgreater than thejfnormel distance between the truck. frame end] the 'main frame; v

4.. In e tractor, and-1n leomblnation a main frame, attractor truck meehanlsm compris ing a "spr0ckett;whee1-,qa truck frame pivotally mounted 'coneentrie. 'With 7.

upward"; tilting movement" of the forward '1' the e'Xis' off the sprocket saijdtriick frame having a p artextending reerwar'dly of the pivotof the 1 truck fraimeya, traetor the forward end of the" truek frame U 5, lua tractor; and in'combinetionfa frame, a tractor truek-{me'chanism compr1s-' ing a driving sprocket wheel, a truek' frame pivotally monnt'edfconcentrie the-exis of the sprocket wheel, se'id truck frame hair;-

in par extending r rdlyof it P W-v total point, a tractorvchain, e eilri ediidler surface, and spring mechanism-foriesi'stingupward: tilting movement of'jtheforwerdfl part of the truck frame; said sp1'ing meehanisincomprising. aiconnectin'g in'emherfsje- .cured at one end to the partfof the truck frame extending rearwardl-y of' -its"pivot;and

having an abutment' near :theother end.

thereof, and a spring member interposed between the main frame end said abutment. I v

.1 whereof h e Signed h neme'to this specificfetion in the presenceof two subscribmg'witnesses, 1 v

"Witnesses: I f l SMYYYTH," f; CHENEY.

.e CLARENCE L BES

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