Patented Oct. 1, 1946 UNITED" 2,408,499 STATES f,„.-;2,408,4_99 PA'ITEI*IFTy v - OF FICEY i _ PIs'roN EXRANDER' Franks.' Wells, Aniançe, ohió- _ ApplicationA August. 21, 1945; Í’SeriaIlNo. 6112750 »i 7 claims. (cli> 309-12) ThisV invention relates to‘a piston expander; The principal object ofthis' invention is` the adjacentïto 'the slot thereof; thusexpan'sionffis directly“ against" the skirts of‘tl'ie piston'. It"’1s possible' by using the device "shown and described provision of a> pistonexpa-nder that maybe used iso-provide the desired expansion to rtheskirt of'ßa piston. A1v further object ot'this-inventio'n is the pro Vision of‘ a piston expander that will provide desired expansion to theï sltirt‘of> a. piston and maintainthe expansionatf all times. ‘ A' still furtherobje'ct ’of this‘invention is the provision ofV a- piston expander incorporating a tension'means whereby the expanding pressure exerted'against the skirts'of the Apiston is 'made flexible so as to Vcompensate for‘the expansion and 'contraction ofthe piston resulting fronrheat. A still' further object 'of thisvinvention is'the provision of' a pistonexpander; incorporating a unique lockingfrneans 'for' controlling the ' degree of y eX-pansîonfto ' which > the Yexpander is set. , It isv well known that many forms of piston expanders have been devised toattempt to- suit ably'expandtheskirtsof a‘piston sufficiently t'o` compensate > for vthe wear ‘of thel piston itself and - herein tore-snapcïthe piston‘thr'ough‘ expanding D the skirt to its original'size or larger so that Ythe piston .will conform .With any irregularities'inî the cylinder wail.. . . With' the .foregoing ‘ and other' objects in ‘View which 'will' appearV 'as the description~ proceeds; the invention" resides inthe; combination. and are rangement ci"Y parts 'and in ‘the details .of 'con struction hereinafter described land claimed; 'it being understood that changes in' the precise'em bodiment'of the inventionv hereinv disclose'dfcan be made4 within the scope of.` what is’ clafin'i‘e'd', Without Adeparting from .» tlieï vspirit ‘ of ` the'- inven tion. . The: invention 'is illustrated in th'e‘accompany' irì‘g'drawine, wherein:A . Fig.' 1 isfa, View. of' Íthe piston expan'dencom' pletelyas'sembled.. Fig.' 2"is a- detail‘v'iewofîa bolt‘ portion'Lof'the expanderish'own in'Fig. 1'. _ the wear of the cylinder-walls. Onetype vof'piston Fig. 3"’i's ’a detail View' of. 'one 'of' the flanged expander known to theartcompriseda circular 25 bushingsishown in Fig. .1. section'of spring- steel. This type maintains a Fig.' 4'is a detail View .of the adjustrn'entïnut continuous expanding ‘ pressure on the piston skirts ‘and usually -sets, up an Aundesirablel pressure onAV the Y 'cylinder-` Walls j thus -' causing' unduel wear. shown‘lnzlï'i'g. 1.4 .. _ _. y . >l1"ig"."5` is a detailviéwhf the 'selfelockin‘gï'co'il springshowninFîgl.. . ' , " " Another type of" expander known to the artcom-` 30 Eig; .6> is 'a detail vieu/"ofï‘the’.other‘ñanged prises a` bolt> assembly positioned between the bushingshown in Fig. 1. _Í . _ . 'struts-of the older type of piston'and'which, Tnelpa‘rts shown inFigs; 2,'3, 4; 5, and-6 come through variousadjustments', provides‘a means prise 4tli'efexpander. shown in Fig'. 1 and‘aresh'own of-v expansion. This- type of expander; such as in- the drawings' approximately the positions ` shown‘in'Patent #2,‘057,327,"wi11, when installed by' anexpert, result in 'satisfactoryexpansion. However, the limitationsxof 'this' form‘ of 'exel pander are‘chieñy‘ due to the rigid u_nyielding expansion'obtained which Will'res'ul'tJ in freezing or -sticking'of thepiston if‘the‘ expander' has'be'en set» a» littletoo‘tight. The‘present' invention is an improvement"ovent'hisV form of'. expander in that it incorporates'the use of'a coil spring` po sitioned abouttlie'bolt'section‘of the' expander in such manner ’that‘the ‘expansion pressure .exerted bylthe‘expander‘is `carril-:fd‘at all timesthrough theícoil spring‘and~ while' the‘skirts‘ ofthe piston may be; expanded to'any' desired deegree, the. incorporation of thecoil‘s‘pring, provides' a ñeXi bility that becomes ‘highly'import'ant when the piston‘itself-'expands due totoperating'conditions In=the-present'invention; Iä provide a piston‘ex panden adapted for Ausevin the-newer forms' of they Aoccupy'wlien assembled. f " _ _ ` Fig.' 'Tis' a modiñed‘form’ of flanged" bushing adapted to' be used‘in place of the bushing'fsh’own in Figj3 when the expander is used in a'piston havings'trut‘s therein. _ . _ ' Fig'."8ïisîa'detai1 viewiof a'm‘o'difled forni of 'the bushing"s'l'iov‘vnV in Fig; Band. isz adapted to* be used' on anlexp‘and'er withrthe b'ushing‘îshown in Fig; 'Twh'en the> expander is .positionedibetwe'en struts‘in‘a'piston; . _ Fig. 9 is a detail View of. a modiiiedf'o‘r‘mcof ` the bon shown innig: 2';y .the-threaded area/being. considerably larger in. size and design’ffor'ex pandersi subjected>l to abnormal expansion.’.pres'-Y sures. _ . Fig.’ 10v`> is -across sectionalivi'ewlof’a ’piston showingfthè expander Vshown in'FigL‘ l’p'osition‘ed therein. A _ BY "referring to' Fig; 1. of* the drawing. it‘.wi‘ll`loe se'en'th'at the vpiston expanderi'c'oinprises 'a fhl‘ëa'ded‘b'oflt Ufa pair 'ofioppositelif disposed un 2,408,499 3 threaded flanged bushings 2 and 3 are positioned on the opposite ends of the threaded bolt I. The flanged bushing 2 being smaller than the flanged bushing 3 and is positioned upon a smaller un threaded end 4 of the threaded bolt I (see Fig. 2) . In order that this flanged bushing 2 may be po sitioned upon the bolt I, a hole 5 has been drilled in the bolt I and a pair of holes E have been drilled in the flanged bushing 2. ’I‘hese holes are adapted to receive a cotter pin 'I. Positioned upon the threaded bolt I and between the flanged bushings 2 and 3 there is an adjustment nut 8 ' and a coil spring 9. Raised portions Ill formed on the ends of the coil spring 9 are adapted to engage slots II in the adjustment nut 8 and' flanged bushing 3. The flanged bushing 3isfpo 4 upon the bolt when it is partially in place in the piston. After the assembly is completed the cotter pin 1 is placed thus positively placing the expander in the piston, and the adjustment nut rotated until the correct expansion is obtained. In adapting this piston expander for use in the new pistons using thermostatic controlled struts, it is only necessary to substitute a thermostatic spring for the spring ordinarily used in the ex pander, thus’accuratelycontrolling the degree of expansion throughout the temperature range of the piston. ‘Having thus described my invention, what I claim is: 1. A piston expander for adjusting the skirt ‘of ‘a slotted skirt piston comprising pair of flanged bushings positioned in openings in the sltioned slidably upon the threaded bolt I and . engages an opening in the piston skirt as does ' said skirt; a threaded bolt slidably positioned through and between the said flanged bushings; the flanged bushing 2. It will thus be seen .that when assembled and positioned in a piston in 20 a coil spring positioned around the threaded bolt and adjacent to one of the said flanged bushings; openings in the piston skirt, the expander will a nut threaded on `the saidthreaded bolt and exert expanding pressure against the piston skirt adapted to move the said coilspring-against-the when the adjustment nut'S is rotating toward‘the said flanged bushing so as to suitably expand flanged bushing 3 thus `tending to compress the coil spring 9 through which all of the expanding 25 the skirt of the said piston. 2..A piston expander -for adjusting the skirt pressure is exerted. of a slotted skirt .piston comprising a pair yof It will be seen that due to the raisedportions I0 flanged bushings positioned in openings'in the formed on the ends of the coil spring 9 and the said skirt; a threaded bolt slidably positioned slots I I in the contacting surfaces of the adjust ment nut 8 >and flanged bushing >3, the adjustment 30 through and between the said flanged bushings; a coil spring positioned around the threaded bolt nut`8 will> be efficiently locked in position at in and adjacent to one of thersaid flanged bushings; numerable locationsas the raised portions I9 en a nut threaded on the said threaded bolt and gage the slots I I. By referring to Fig, l0 the ex adapted to move the‘said coil spring against the pander will be seen-positioned between the op said flanged bushing; the said flanged bushings posite sides I2 of the skirt of the piston and ad formed so as to conform in shape with the inner justment to the slot I3 therein. It will also be seen that due to its location it does not interfere with the adjustment wrist pin bearings I4. When it is desired that the piston expander be positioned in a piston formed with struts there in, it is necessary that the flanged bushingsî and3 be removed and modified ñangedbushings I5 and I6 (see Figs. '7 and 8) beused so that the flanges thereon are fiat and will suitably engage the struts of the piston. Otherwise the expander sides of the .said ypiston skirt so as to suitably expand the skirt of thesaid piston. 3. A piston expander for adjusting .the struts of aslotted skirt piston comprising a pair of flanged bushings positioned in openings Vin the said struts; a threadedbolt-slidably positioned through A.and between the said »flanged bushings; a coil spring positioned around the threaded bolt ' and adjacent to. one vofthe said flanged bushings; projections formed on the ends of said coil spring, a nut threaded onthe said threaded bolt and adapted to, move the .said coily spring against the saidflanged bushing so as to suitably expand the of the pistons being manufactured areprovided with openings in the skirt in which the. expander C, o struts `of the said .piston vslots formed crossways in- said nut andthe .,last. mentioned flanged bush may be positioned, it is a simple task todrill ing„for registry with said projections on said openings in pistons not so equipped. It will also spring, an opening in said .bolt and rin Ione of said be seen that if the outer endsof the flanged bush flanged bushingsand akey-.positioned in said ings2 and 3 extend through the skirt I2 of. the is exactly the same as that yused in the newer forms of pistons in which there are ,.no.struts. In this connection it will be seen that while some piston that may be easily removed bygrinding CII Ui openings so as to lock »the saidbolt to the said flanged bushing .and thereby preventing the rota either before or after the device hasbeenin tion of the said bolt, the registration of the said stalled inthe piston. When the piston expander is used in pistons subjected to extreme pressure such as in heavy duty air compressors, it has been found desirable to form the threaded bolt as shown in Fig..9, wherein the threaded section I‘I is considerably larger than normal so that a larger adjustment nut may be used to insure suffi cient expanding action as the adjustmentnut is rotated. In order-that additional adjustment may be made, the smaller unthreaded end .4 of the threaded `bolt I is provided with aslot I8 cut‘ into the end thereof so that a screw driver Nor similar tool maybe used to rotate the bolt. In installing .this piston expander ina piston, it is necessary that the flanged bushing 3 be in stalled ñrst, the threaded bolt I then, being passed through this flanged bushingß into the piston and projections on the .spring with the slots in the said nut and the flanged'bushingV preventing the rotation of the said nut on the said bolt, raised portions formed on the ends of the coil spring and slots formed on the said nut and the said flanged bushingso that the said raised portions of the spring register with the said slotsto form locking ' means to prevent thenut frornrevolving on the said bolt, and an >opening formed in the said bolt and in oneof the said flanged bushings, and a key positioned in the ,said opening so as to lock the said boltto .the [said ,hanged bushing and thereby prevent its rotation. 4. The Acorn'binationof a piston comprising a slotted piston skirt having oppositely disposed openings therein; anda piston expander com prisinga pair ,of flanged bushings positioned in the various other portions ofV the device placed 75 the said openings; a threaded bolt positioned 2,408,499 5 through and between the said bushings; a coil spring positioned around the said threaded bolt and adjacent to one of the said flanged bushings; i a nut threadably positioned upon the saidthread-> ed bolt adjacent to the said coil spring and serv-- ì ing as a means of moving the said coil spring through and between the said flanged bushings; a coil spring positioned around the threaded bolt and adjacent to one of the saidiñanged bushings; a nut threaded on the saidthreaded bolt and adapted to move the said coil spring against the said flanged bushing; the said flanged bushings and the said ñanged bushing in relation to the formed so as to conform in shape With the inner said threaded bolt and the other fianged bushingA . so> as to suitably expandthe skirt of the said 10 5. The combination of a piston comprising a sides of the said piston skirt; an opening in said piston. f - ' slotted piston skirt havingparallel struts there in, the said parallel struts having oppositely dis posed openings; a piston expander comprising a pair of flanged bushings positioned in the said openings; a threaded bolt positioned through and between the said bushings; a coil spring posi bolt and in one of said flanged bushings and a key positioned in said openings so as to lock the said bolt to the said flanged bushing and thereby prevent the rotation of the said bolt. 7. A piston expander for adjusting the skirt of a slotted skirt piston comprising a pair of flanged bushings positioned in openings in the said skirt, ~ a threaded bolt slideably positioned through and between the said flanged bushings; a coil spring tioned around the said threaded bolt and adja positioned around the threaded bolt and adja cent to one of the said ñanged bushings; a nut cent to one of the said flanged bushings; a nut threadably positioned upon the said threaded 20 threadedl on the said threaded bolt and adapted bolt adjacent to the said coil spring and serving to'movíng the said coil spring against the said as a means of moving the said coilspring and ñangedibushing; raised portions formed on the the said ñanged bushing in relation to the said ends of the said coil spring; slots formed in the threaded bolt and the other flanged bushing so said nut and said ñanged bushing, between which as to suitably adjust the strutsfof the said piston 25 the said coil spring is placed, so thatvthe said for the purpose of expanding the skirt thereof. praised yportions of the spring registers with the 6. A piston expander for adjusting the skirt said slots to form locking means to prevent the of a slotted skirt piston comprising a pair of nut from revolving on the said bolt. flanged bushings positioned in openings in the said skirt; a threaded bolt slideably positioned 30 FRANK E. WELLS.