CA2226812A1 - Vehicle with rear traction kit - Google Patents

Abstract

An all terrain vehicle in one embodiment provides greatly improved traction.
The vehicle includes a grooved rear wheel, a suspension system, and a cleated track with an endless ridge on the driven surface of the track. The ridge cooperates with the groove to align the track on the wheel. During forward propulsion, the track passes under the rear tire then rearward under two bogeys, then around an idler assembly and back over a third bogey back to the wheel. On level around, the suspension system locates the bogeys and the idler so that the idler guides the track away from the ground. Each bogey aligns the ridge in a gap between tapered surfaces. Tapered surfaces remove debris from the driven surface of the track. The idler aligns the ridge between pan shaped rims. The suspension system includes a swing arm hitch and a shock absorber. The swing arm pivot is located behind and below the rear axle toallow movement of the idler assembly in a wide vertical arc for forward and rearward propulsion over uneven terrain.

Description

Ti~le of InYention: ~fEHlCLE W~H REAR TRA~nON KIT
Inventor: Robert Shanahan nF.C:CRlPTl~N
.. , ~bni~l Fie~
Em~dirrsents of ~he pres~nl imention r~ senerally to off-road ~ehicles and to systerns for imp~o~n~ the tradion o~ mot~r ve~icles.

~ar:~rountl A~ an introduction to ph~ ,s solved by the ~uf~s6nt invantion~ considcr the convt,llliGnal ;~ errain Yehi~le ~AT~. SUCh a motor vehiclQ is used to acc~ss remote 10 ar~as ~orc~ ercial and spons pl~poses, sud~ as ma~n~ainin~ f~nc~ a~ ~ch lines, herdin~ anl,l.~ls, can~ping, and hunting, to namQ a tew re,~rt7sen~ti~ ses.
A~ssi~o AT~ drivars, and ss~ecl~'ly novio~ drh(~rs, often 1., jt~d~e the hnd of terra;n tha~ the AT~f ~ s;~tely pa~s over, wi~ r~sulffng nsk o~ personal inju~ and eq~ 3",enl ~"~age.
t 5 Ait~ h some co~ .n;Gndl A~fs exhi~ c~i.. ,;.l~rabl~ ion, such conventional tr~ction sys~ems are in~ecl~J~te for many common typ~s of ~errain For 'o, a ~whesl driYe ArV with cleated tinss has insufficie~t tra~ion for us~ in r snow, J~ lan~s, or steep rnuddy hillsid~ In th~se eltallen~ing condr~ions, ~he conventi~n~l ATV may slide, la~k sufli~ie~t steerin~ or br~kin~, overturn, or become mired. F~rther, the c~nventicnal ATV has insufficient reverse drive, stearing eapabilit and tra~tion to af~1y r~tr~ rom ~r av~id ,or~ceeding fu~th~r into such terrain.
ConYersion kits ar~ comrnercially a~ai;-'-'e for suppiementing the convention~l 5 Z-wheE~ d~ve ATY. To install one sUch kit, lhe user r~ ~s each rear wh~l with a heaYy, ~wkwar~ tra~or ~ssembly similar in op~ration to a conv~ntiQnal snol,~ "~oL~ile track The conversi~n may r~qui~ arl array of power tools, mechanical skill, sp~dflc training, and su~ l time to accornplish corr~c~ly.
~ithout a simpler trsotion improvement kit that can ~e distri~uted and sold at ~n 10 affiordabl~ pnce and easily installed by the unskill~d ATV owne~, ATVs will oontinuB to find little or no ~FFIi.,~;cn durin~ e~ended porli~ris of the year includin~ for example wTnter n,~,~l,s and w~t s~ng and fall m~n~hs. Without a li~ht weight, ~liable, and oomparatively inexpensive ,n~ltod of improving AlV traction, the AT~ owner may needlessly risk p~,~ol~al injury for himseH or 3~a~anlizQ the safety o~ other~ by attol."~n~ to o~erdl~ an ATY wi-thout su~ficient tr~ction ov~r terrain all too co~lln~on in thQ remote areas of our country.
tn YiBW of-the problems describ~d a~ow and related pr~blen~s that cons~qu~n~ly hecome appar~nt to thos~ skilled in the ~r,plit~'~ arts. th~ need l~,..~ns in all-terrain Yehicl~s lor sysl~ms for improYed traction.

2~
~':UMM~P~Y OF TI~F INVFr'lTlON

Accor~in~ly, an all-terrain v~hicle in one embodiment of the pressnt inYention inGludes a motor Yohi~, a suspension system, and an ~ndless tr~ck. ~he motor 2!i YehiCIE3 has a rcar wheel ~ith a drive sutface cherd~ ~ize~ by a cr~ss section. The cross s~ion has a first portion with a first radius from the center ~f th~ wheel, a second partion with a sec~nd smaiier radius, and a third portion wnh t~ fir~t radius;
ths se~ond por~ion bein~ be~ n ths fir~ and third portions. The suspension system connccts to the vehiclc and supports an idl~r r~anNar~ of the wheel. The endless track extends l~l.~ the wheel and thc idler The track indudes a protrusion that extencls towar~ the sewnd portion of lhe dnYe surface te n,cuntain ali~nment of th~ tracc on the wheel Accorciin~ to ~ first as~eçt of such a vehicl~, cooper~lion of the track protrusion and the driY~ surface te~tures ~comi~ishes ali~nment without use of the side w~lls of the wheel. Prior track structures tha~ ccoperate with th~ side walls of the wheel ar~
oo""~a~ti~ely ~ vensiv~ to manufacture, bulky and thetefor~ ~stly to shiip, and unreliable due in part to accumulation of debris between the sid~ wall and the stnlctures.
Aoco~riin~ to an~th~r asp~ traction superior to a cQnventionai 4-whsel dtivQ
vehic~e is ac~h' i~d with a 2-wheel driw3 vehicl~ of the present invcntion, withc~nseq~ential r~du~ed initial ~Qsts and op~r~lin~ costs.
o in an alternate embodim~}nt, th~ icller includes a plur~l;ty of rims that coop~3rate wlth the track protnJsion. Accor Jin~ te an asi~t of such an embocii~ rlt, the idbr ali~ns the track with light~r and n~or~ rclia~ls construotion as compareci to prior trac~
systems that duplicat~ th~ r~ar wheel construcHon forthe r ar aliDnment ~unction.
Consi~i~r~le cosl r~ductions in manufactu~in~ and shippln~ r~su~lt. Acc~l~l;n,,~ to 15 another aspQct, low~r inertia in th~ idler wmpared to prior systems i~roYid~s quicker s~art-up plopulsion ~nth less engin~ power and oonsequently less risk ol en~in~
~v~rhoatin~ dvring frequent stalt-stop op~rillions.
In yet another alterrlat~ embodiment, the suspension syst~m supports the idler and a iW~ey in r~lation to a leY~I surfa~e und~r the ~ehicle so that the Wler ~uides th~
20 track ~way from th~ ievQI surfa~. A~ ing to an aspec~ of such an emb~diment, the track is guided u,oward over fra~mentary and fluidic terrain when the vehicle is dr~ven in re~rerse. Rath~r than dig~in~ into the terrain and burying the track~ the sl-si~nsion system p~rmits th~ track t.~ plow as it iifls the Yshicl~ o~rer such loose te~rain~
Accordin~ to a second aspect of such an ~mbodiment, vehid~ weight is 25 distributed in part on ths bogey, fa~il;ldting ~urning th~3 v~hicle.
In sffll anoth~r ~"~ li",en~ of th~ s~lll in~ention, th~ bo~y has an hourglass t~per Accardin~ to an a~p~ct of such an embodiment, inor~asin~ tensi~n in the track i" "~des pr~ ss o~ a protrusion away from the a~igned pesition of th~ track on the bo~y~ Mor~ reliable op~ ion of the track results durins periods when dsbris 30 Qnters l~e~ en the track and th~ dri~in~ and ~ y surfaces f~r the track. AccorJi,~
to ~,~tl-er aspect, d~bris is cleared from the inner surfa~e of the track dunn~
operation -These and other embodirner~ts, aspeo~s, adYar~tages, and teatures of th~
p~esent imfention will i~ sQt fo~h in part in the descnpUon which follows, and in part will becorne apparent to those skilled in the art by reference t~ the following des~ription of th~ inY~nlion and r~Qrenc~d drawin~s or by practice af the invention The aspeats, adY~nta~es, and features of the invention are realized and attained ~y means of the instrumentalities, p-ocedures, and oombination~ particula~ly pointed out in th~ appendsd cl~ims.

RF~I~F nf~ lPTlON nl~T~F llRAWIN~-~
~ o Fi~ure 1 is a tc~p view of the rear portion of ~ vQhicle in one embodiment of the present invention.
Figure 2 is a side vi~w ~f thQ vehicle porlion shown in Fi~ur~ 1.
Figure 3 is a oross section of a track of the vehicle shown in Fi~ure 1.
Figun~ 4 is a cross se~tion of an idler assembly of the vehi~le shown in Fiyur~ 1.
~i~ur~ ~ is a is a top Yi8W of the c~lindrical bo~ey sh~wn in Figure 1.
~ Figur~ 6 is a parbal side Yiew of an alternate tu~ structure us~d in plac4 of tubes 34 an~ 38 shawn in h~ure 1.
Figure 7 is a cross sec~ion of an al~ernatQ trac~ for the Yehicle shown in FiDurQ 1.
Fi~ure 8 is a cross section o~ an alternate idler and track ~or the Yehicle shown in Figure t rlFTAII Fn nF.~cpllpTln~ nF THF II~NFhlTlt~N

Fi~ur~ 1 is a top v3ew of ths rear pwticn of vQhicle 10 in one enl~o~lnlent of the present inYention. Vehicle 10 in~ludes a conventional ATY frame, motor, body, front wheels, vehid~ susp~n:,ion system, and ste~rin~ syst~m not shown. In ad~lilio,~,vehicle 10 indudes rear wheels 1~ and 16, track 20~ and sL~spens-~n ~ystern 6.
Conventional frama ~ n-ber 1~ extends r~arwar~ and is supported on a~le 14 by b~aring housing 11. Axle 14 includ~s spro~t 24 an~ is ~here~y driven by chain 22from ths nlo~or, ru~t shown. Whe~l 15 and wheel 16 turn with axle 14 to prop~l vehicle ach wh~i includes a tire mounted on a r~m in the ~onventional manner.

ImproYed traction is obtained by molJntin~ ~ track over ea~h rea~ wheel, exemplified by tra~k 20 shown. A corresponding track 120 o~fer wheel 16 is shown only in part so as to reveal track ali~ning and traok guiding slructures.
Track 2~ is ~hown ;~s an endless gener~lly one pi~ tra~k Tracks 20 and 120 s are identical with cor~s~"c~in~7 cleats 1~ and 11~ and cJrr~onding rid~es 23 and 123. In an aiternate embodirnent, lr~ck 2~ is form~d by joinin~ seYeral i~entical traclc ctions t~ 11.or by ~nventional butt hln~es, not shown. In such an ~mbodiment thecl~ats and ri~e are ~ast with thc suibstrate scction or ~It in a ~in~le operation.
Polyurethane is a pn~i~arre~ material, th~ugh similar clurable plast;cs and s~"t~lic 10 rubi~r cQmpounds ar~ practi~al~
Susp6"sion systQm 6 inciudes upp~r ~v~ld",~nt 41 and s~in~ arm assenlbly 51 U~r w~ldment 41 is ~l~cl~ed to frame mernbQr 12 by ~o~ing tubes 34 and 38 throu~h iJars 26 and ~8 with bo~s ~0 and 32, as shown in Fi~ur~s I and ~. Bars 26 and 28 are weld~d to frame member 12. ~rcss tubs 3~ is w~lded to tubes 34 and 3~.
Angles 40 and 42 are w~lded t~ cr~ss tube 3~ ~or supporting the uppef end of shock ,~r 4~ by pin 44. Hitch plate 9, welded to housing 11, pro~ides a conv~ntional mountin~ ~or a trailer hitch ~all. With th~ ball r~moved, bolt ~3 ~l~l~s ~ross tu~e 36 to hiteh plate ~ as shown in Fi~ure ~.
Swing arm assembly -~ includes tubes 48 and 50 r~specti~ly pi~r~ted ~rom tubes ~4 and 3B as shown in Figur~s 1 and 2. Tube 48 is pi~ot~d at pin 112 thr~u~h tabs 1 10. Tabs 110 aro welded to tube ~4. Pin 1 12 defines a piYot a~cis located as dose as ,~r~-411y feasible b~hind axl~ 14 and somewhal lower than axle 14.
Di-,lQn .ions of the ooop~r~tind "-~"~ber~ are chosen usin~ Gom~entional t~chnl4~es in altema7e ~ od;,~ents to ra~ ila~ an app~pnale vertical range of motion ot swin~
2~ arm assen~biy S1. As shown, swing arm assembly 5ti exhibils both downward and upward arc moY 3ment fr~m th~ illustrated ori~ntation while n~ainl~ining sufficient Lbn~iQn in tracks 20 and 120.
Tubes 48 and 50 ar~ wel~ed 10 C~SS tubes 54 and 66. Stu~ tubes ~2 and ~3 aro weWeci to tubo 4~. Stub tubes 5B and 57 are wslded to tube ~Q. T~bs 70 and 7are w~l~ed to cr~ss tube 66 and provid~ piwtal mountin~ for the iower end of shock al.s~,l~r ~6 by pin 68. Each h~be, 48 and 50, supports one of b~ symmetrically identical track ~uide assem~ies. The track guicie assembly obscured under track 20 Is attached to stub tu~s 5~ and 57 by pins ~1 and 74. In a sin~ r mann~r, stu~ tub~s 52 an~ ~3 support tra~k ~uide ass~mbly 81.
Track s~uide asse~ ly ~t in~ludes basa htbe 82 t~ ~NhiGh telçscoping stu~ tub~s 58 and 6~ are welded. Teles~oping stu~ tu~s 58 ~nd 62 are rac~iv~d by stub tu~es52 and 53, r~sp~ctively, and held in place by pins &0 and 64. Tubes 58, 62, ~2~ 5~, and pins 6~ and 64 exemplify means for positioning tra~k guid~ assembly 81 ~ehind r~ar wheel 16. This means for ~sf~ionin~ accommod~tes variation in wheel base "ensi~n ac~oss difler~nt nodels o~ ~onYention~l AlVs so th~t common parls can be~upplbd for various fi~ld .~rp~1~7ti~ns. A minimum whe~l baso ~ppli~ation is o illusL.t~ed in Fi~ur~ ~.
~elesc&p;n~ b~r 90 slides within basQ tubs ~2 and rides ~ainst tension a~juslnle~ w 76 when endless track 1~0 is in pl~c~ around wheel 16. Axl~ 99i5 welded throu~h ~ar 90 and supports pan-shaped rims g~, 94, ~6~ and 98 in a manne~
to be furthQr cles~nb~d with r~hEr~nce to Fgure 4.
s Cylindrical ~oaeys 101 ~see Figur~ 2), 84, and symmetncal counterparts o~scur~d under track 20, support swin~ arm ~sser"~ly 51 by ridin~ on the interior, driven surla~e of tracks 1~0 and ~, while the n~speclive t~ack is in cQntact with the terra~n under Yehide 10. Bails 105 and 88 are welded to lhe underside of base tube 82. 80~Qys 101 and 84 are mounted with intornal l~e&rings on shafts tO3 and 86, held 20 in place by conventi~nal means to ba~ls 105 and 88.
Shock absor~er 45 opsrE~tes in ad~ition to v~hicle susp~nsion system, not shown, that is responsive 10 moY~ment o~ axle 14. Bocause vehicle we~ht Is distrlbut~
on both axls 1~ and onto bo~oys 10t and 84, shocks ssen independently by a~cle t4 and bogeys 101 and a4 are dl~sGrL~d by the coo~r~ n of the vehid~ su~ ,;or) 25 system and shock ~s~,~sr 45. Track contact with the terrain is thereby maintained f~r a wide variety of relative mo-,emenls of a~cle t4 and bogeys 10t and 84.
In alt~r,l~e er~ Jl-"~nts, bar 9û en3~9es a co~ r~ssion spring within bas~
tube ~2 for maintaining tension on the track. In one such ~r~ tl, adjustin~
screw 7~ is ~li.llln~ wllh the result that traclc ~ension is aLltomatically rnaintained 30 without inteNen~ion on a widu variety of ATV models.
Fi~ure 2 is a sid~ view o~ the portion of Yehicle 10 shown in Figur~ 1. Wheel 16and tra~k 120 are not shown ~or clarrty. Suspension system 6 locates bo~ey 84 an~

idler assembly 91 so that ths track aligned by these strudureg is guided ver~cally away from a leYel surface on which vehlclB 10 stands. In one embo~innent, the lowetrno~t su~ac~ t}f idl~r ~sssmbly 91 is about 2 inches abo~ the bwer su~face of ~o~ey 84. Accordin~ly, .when vehW~ 1 Q iS operat~d in .~rse, th~ po.~tion o~ track under idler ~1 opefat~s to lift vehicle 10 over the tefrain rather than to pf~duce ~dditional fragmentatlon o~ the terrain which oould mir~ the traGk.
Th~ retative locations o~ ey 84 and idler 91 as taught her~in pr,ovide ex~el~nt opel~dlion in ~r. _.~1 and .~verse ove~ powder~d snow and o~er miry clay.
Bo~y 78 is s~po-Lsd ~n sha~ ~0 via baii 7g. Bail 79 is welded to tube ~. Tube 83 is welded ~o base tuba 82. Bo~eys 78. 101, and 84 afe id~ntical. Bails and sh;~fts supporlin~ thes~ ys a.~ also id~ntical. Each bo~ey ope~al~s to ali~n track 120 and to ~emoYe d~b~is f~.~m the dfivsn sur~ac~ of track 1~ às wili be described b~lowFj9UrH 3 is a cross ssction o~ tra~k 20 of whicb 10 shown in Fi~re 1. Track 2 includes cleat l9 joined by a con~rentional technique to belt 29. P~id~e 23 is allached to belt 2g ~y oonYenl;onal ~aslener 2t .
Wheel15isidenticalto whesl16 ~ndinclud~s ~roo~ 118,notsh~wnthough ide,~icalto grQo~e t8 ofwheel1~. Whsel15,pa~cu~ythe mbber tire po~ion, makes driving conta~ withtr~ck2~ along a dri~e sur~ac~ cut to revealth~ cross ~ection ofFi~ure 3. Rid~e 23 prot~des from belt2ginto a po~ion of the su~ace of ~Q wheel1S,diYiding the drive surlaoe into a;t least thr~e portions. Surf~o~ portion 31 e~L6rl~ generally frorn the inner sid~ wall of wheel1~ towa~ ~roove 118 and is ~ine~ ~y radius 27 measu~ed ~om ~ntral axis 13 of axle 14. Surface portion 33 ~xtonds çjenorally firom the outer side wall Qf wheel 15 towand ~rooYe 118 and is also d~fi--~d by.-adius 27 me~sured from ~xis 13. Surfaoe portion 17 at the base of the central ~roove lies ~etween surface ~rtions 31 and 33 and is defin~d by radius 25 meas~r~ from a~cis 13.
The shape of ~JrvO'~8S 18 and 118 and of rhiges 1~3 anci 23 ~ol,f~.~" to a V-~ltand V-pulley standarFi char~en~d ~y ~ 40 dcgree angle deffnec~ by the sides of the "v" or gr~oYe~ Rid~e 23 flts proove 18 with a nominal gap in tihQ range of 0.005 to 30 ~:1.100 Inch, pr~i~,~ 0.0~0 inch, exag~er~led for clarity in Figure 3.
i-içlllra 4 is a cross s~c~ic)n of id~e! assem~ly 91 of Yehioie tO sinowrl in Fgure 1.
Bar 90 supports 4 id~nlTcal pan-sha;ped rim~. Each rim is supported on a bearir~, for CA 02226812 l99X-01-09 ~xarnple b~arin~ 102 of rim gZ Sel screw 104 in an int~ral collarof bearin~ 102 assures proper spaang ~etween rims so that track 120 is supported and sligned.
Fi~ur~ 5 is ~ top Yil~W O~ cylindrical ~o~ey B4 sh~wn in Figu~ 1. The ciian~ter of ~ag~y 84 is smallest within central ~rooY~ ~g. ~oni~al surF~ces ~5 and 87 define 5 groove 89 and op~rate to increase tr~ck tension as track 1 2Q wanders f~m proper alignment. Conical surf~es 85 and 87 are sy",n)el~ l and hrm a shape havin~ an hourglass t~p~r. C~onioal surfaces 85 and 87 in~ease In diameter lin~arly wiSh lloriL~nt~l p~sition. In th~ illustrat~d embQdim~nt, bo~sy 84 me~sur~s about 4 inehes in di~n,ç~ter by about 11 inches in len~th. Thc taper over about 5 inches of la~Bral 1 G surfa~ results in a ~e~r~ase in di~m~ter in the rang~ of 0.1 to 0.9 inch, pref~ ly 0.375 inch. In altemate e.~bod;m~nts the ;~ se in ~ L.3r, i.~. ~he hour~lass tap~r, fonows a p~-~balic, an exponential, a s~ment~d linear, or ~ cornpound cuNe function of hori~Gnt~l ~Jos;l;~l~.Bogsys f 01, 84, and 78 io onB ~llb~dilllent arc fonn~d of UHMW plastic c~t by lath~. Jn ~n alternate e~ di,il~nt, these ~ogeys ar~ cast of . 15 polyurethane.
When bo~ey ~4 is s~ .~n;ng a~ainst th~ nwvins drive surface of track 1~0 that isIffler~d with debris such a~ snow, mud, sand, ~raY~I, or veg~t~tiorl, thp4reci surfac~ 8S
and 87 coopera~e w~h app~opri~e tlexur~ of track 120 und~r the wsight of vehicle 10 tc slough the debris off the drive surface. Without such a s~lf cleaning capabir~
20 ul~9~1iorl in the prQs~nce of such debris wouW either stal~ vehicle 10 or u~e traeik 1~0 off wheeJ 1&. This s~lf ~leaning ~Ar~h~ y ~cilit~tes sa~ lel and hi~h speed propulsion using a minimum of dri~ls tor~ue and dnve pow~r.
Fisur~ ~ i5 a partial side Yiew o~ an alternate tube struc~ure. In many ~wtor whicl~s similar in other resr e~ to the cQnvent7onal vshicle shown mociified 25 acco,~ to the p~e~er~ inYention in Figure 1, a hitch pl~t~ ~imiitar to plate ,i 1 is provided; ho ~a~r, no slruçtur~ for anachin~ i~ars 26 and 28 is available for supp~rlin~ upper ~ l~rll 41. in addition, in such sirnilar oonventional v~hiclHs, axle 1~ is surround~d at i~ast toward one wheel by a sul.~anU~I housing. When ;t is dQs7red ~o aKach an aKernate uppsr w~ldment slmilar to upper weldm~nt 41 to such a 30 vehicle aco~r~ to the present ir-~entlon, use is made of the structural integrity ot the ~Lxl~ housin~ as shown in Figur~ 6.
An alternat~ upper wel~m~nt 141 Includes tube 1~8 cerrespon~in~ in al1 other rsspects to tube 38 of upp~r weldmen~ 41 shown in Figur~ 1. Tube 138 include~
U-bolt 129 which is wel~ed thereto. U-~olt 123 is similar to a conYenlional exhaus~
clamp, having forfned p~ate 122 fld~rted for grippin~ a cylindno~l surfa~e within U-bolt 129. Nllts 1~4 o,~ t~ to ma~ntain a cylindrioal portion of axle housing 128 within 5 U-bolt 1~g and thereby prevenl upper .~ vrlt 141 from turnin~ in any of three axis about iits other all~Ghl~,ent pQillt lhrough hitch plate 9 r~es~bed with refer~nce 10 upper ~v~ ent 41 and Fi~ures 1 and 2.
In c~n,~s~ to upper weldment 4 t whlch attaches t~ the r~ inder of vshicle 10 at three points, alternate w~idmRnt 141 atl~che~ at two points.
Fi~ur~ 7 is a cross section of ~n all~n.at~ traok forthe vehicle shown in Fi~ure1 . Track ~2~ with cleat 21 g and rid~es 222, 223, an~ ~~4 is a one piece ~asting of polyur~thane. Numbered items 219, ~3, 225, 227, 231, and 233 correspond in structur~ and ~uncti~n to iterne 19, 23, 2~J ~7, 31, and ~3, des~ Je-l with ~f~r~nce te Fi~ure 3. Additional ridges ~ and ~24 illustrate p~otrusions on separ~e para~bi 15 linear arrangements. Rid~es 2~2 and 22~ cooperate with tire ~r~ad culv~tur~ of wh~el 15 to ali~n ~rack 2~ on wheel 15.
Fi~ure 8 is a cross s~ction of an altemato idle~ and trac1s for the vehicl~ shown in Fi~ure 1. Id~er 291 supports and all~ns tr~ck 2~0, ~e~cr~ d with rsfer~nce ~oFl~ure 7~ using componE~nts a3ready d~seri~3ed with re~eren~e to Figures 1 and 4, excep~ in an orie~ ~.l better suit~d to atiynin~ track 220.
The ~ore~oing deso.i~3l;ion di~ulss~ pr~errs~ embodiments of the pr~sent inven~ion, which ~ay be chan~ed or m~dified without de~,li.,g ~rom the scope of the present i~ nlian. For example, ridy~ 23 in altsmate e,~ edi",en1s is endless as whQn forrned of s~- "ants in butt contact so as to be practically c~r~nuous. Rid~e 23 iS an exampb of a protn~sion from tr~ck 20 to be recei~r~d in a sur~aoe struct~lre o~
whesl 16. In ~n ~l~male embodiment, rid~e 23 is ~epls~Y3d by a series of se~ments, kn~bs, tQeth, or tha like either in continuous linsar arrangement or in spa~ed arr~ el~lent.
In still further embodimonts more than one nidge or p~trusion is r~ceived ln oneor in a plurality o~ ~rooYes or surface struclur~s of wheel 16. Such ~rooves arsarr~nged with or with~ut resul~ing in an endless surface teature.
In hrther altemate ernbodiments, fewer and altemate bo~eys ar~ use~ in pla~

CA 022268l2 l998-Ol-09 of one or two of the bo~ys shown in h~ur~ ~. For exampl~, in one such altern~te embedirnent, a convQntional split wh~el bo~ey replaces bo~y 78, and bogsy ~01 i~omitted. In anoL~ler embodiment, bogeys 7~ 1, and B4 ar~ fwmed with ~ne ~roo~re fcr nd~ ~3 and no fur~her ~roo~es for rid~s 222 and 2~4.
Slill furthe~, those shlled in the art will understand that idl~r assembly 91 asshown is sufficient lo coopera~e with on~, two, thr~e, f~ur or fiYe parailei linear ~rr~ngen.er,ts of protrusions or endless ~id3ns on track 20. Com~entional sirnplifications in the desi~n of idler assumbly gl ~or op~ration with more or fewer ridg~s are c~3nsid~r~d mer~ desi~n choice.
Welded connectiorls are re,~laced with o~n~ ~nlional fast~ners with requisite ~mponel~t modifications in alt~mate embodlments for reducin9 the ov~rall shippin~
~li,nensions when dis~ssem~le~. Additional markets for vehicle modification kits arQ
,~:acl~ed lhrou~h complian~e with shippers' dimensional ~uidelines and Itnli~liG,.s.
In ~n altemate e,.~ ,ent i~ler g1 is roplaced with a s~rooYod wheel formed usin~ conYsntional rim and nJbber tir~ te~hn~ ies or Gast using comrentionat piastic ~asting tschnologies, to name a few representative manufacturing teehniques.
These and other chan~es and modifications are intanded to ~e includod within ths so~pe ~f th~ present inventi~n.
As used in thi~ sreri~Ation and claims, the w~ wheel~ includ~s its broad con~Qntional m~anin~ and is not limited to a hub and tir~ combination. An ~endbss"
lrack or surfaoe feature includes a continuous, a se~mented, or a notched track or ~urfaoe featur~.
Whil~ for the s~ke of clarity and ease of description, several spe~
ernbodi-llenl~ of the invention haY~ ~een describsd; the soop~ of the invention is intended to be measur~d by ~he claims as s~t forth b~l~w. Ths deso~ ion is net intended to be exhaustive or to limit the in~fention to the torm rlisr~ssd Otherelnl~odi"~ents of th~ ntion wilt be apparent in light of the ciiccl~sure and by practice of the in~ntion by one of ordinary s~'ll in ths art t~ which the inventior~ app ies Althou~h this inYention has be~n descliLed aboYQ with referenoe to particular 3~) means, materials and ~mba~iments, it is to b~ un~rstaod that the invenlion is not lirnHed to th~sc ~ hs~d particulars, ~ut extends instead lo all equivalents within the soope of the follo~Yln~ claims.

Claims (20)

1. An all-terrain vehicle comprising:
a. a motor vehicle having a rear wheel with a center, the wheel comprising drive surface having a cross section comprising;
(1) a first portion characterized by a first radius from the center;
(2) a second portion characterized by a second radius from the center, the second radius being less than the first radius, and (3) a third portion characterized by the first radius, the second portion being between the first portion and the third portion;
b. a suspension system, connected to the vehicle, that supports an idler rearward of the wheel; and c. an endless track driven by contact with the drive surface, the track extending between the wheel and the idler, the track comprising a protrusion that extends toward the second portion of the drive surface to maintain alignment of the track on the wheel.

2. The vehicle of Claim 1 wherein the cross section defines a groove along at least a portion of a circumference of the wheel for admitting the protrusion.

3. The vehicle of Claim 2 wherein the protrusion comprises an endless ridge.

4. The vehicle of Claim 2 wherein the track comprises a plurality of sections, each section comprising a respective protrusion.

5. The vehicle of Claim 4 wherein the respective protrusions form an endless ridge.

6. The vehicle of Claim 1 wherein the suspension system comprises a shock absorber.

7. The vehicle of Claim 1 wherein the idler comprises a plurality of rims.

8. The vehicle of Claim 7 wherein a rim of the plurality is pan-shaped.

9. The vehicle of Claim 1 further comprising a bogey supported by the suspensionsystem between the wheel and the idler, the bogey comprising an hourglass taper.

10. The vehicle of Claim 9 wherein the suspension system supports the idler and the bogey in relation to a level surface under the vehicle so that the idler guides the track away from the level surface.

11. A traction kit for installation on a motor vehicle, the motor vehicle comprising a driven rear axle, the kit comprising: a suspension system to be connected to thevehicle, the suspension system comprising a bogey located rearward of the axle and an idler located rearward of the bogey, the bogey and the idler located to guide a provided track driven by a provided wheel connected to the axle, the idler located to guide the provided track away from a level surface on which the provided track supports the provided wheel and the bogey.

12. The kit of Claim 11 further comprising a tire to be mounted on a provided wheel connected to the axle, the axle having a central axis, the tire comprising a drive surface having a cross section comprising:
a. a first portion characterized by a first radius from the axis;
b. a second portion characterized by a second radius from the axis, the second radius being less than the first radius; and c. a third portion characterized by the first radius, the second portion being between first portion and the third portion.

13. The kit of Claim 12 further comprising a track installed to encircle the tire and the idler, the track driven by contact with the drive surface, the track comprising a protrusion that extends toward the second portion of the drive surface to maintain alignment of the track on the tire.

14. The kit of Claim 13 wherein the cross section defines a groove along at least a portion of a circumference of the tire for admitting the protrusion.

15. The kit of Claim 13 wherein the track comprises a plurality of sections, each section comprising a respective protrusion.

16. The kit of Claim 15 wherein the respective protrusions form an endless ridge.

17. The kit of Claim 11 wherein the suspension system comprises a shock absorber.

18. The kit of Claim 11 wherein the idler comprises a plurality of rims.

19. The kit of Claim 11 wherein a rim of the plurality is pan-shaped.

20. The kit of Claim 11 wherein the bogey comprises an hourglass taper.