USRE21557E - given - Google Patents

Description

'Reimed sept. 1o, 1940 Fredvlvmllagelmmmtol'he Perfect Circle (2l-Illy. lhgusbwn. Inl.. a carpal-attendi rill Nw 41,143, ,m 23,

tionfarreinellwggsehllto.

' seu- My invention relates to piston ring expander: for internal combustion engines and the like, and ithastodomorepartlcularlywlthexpanders ofatypeembodyingasupportingbandadapted l tobemountedinapistonringgrooveandcarry ing a plurality of spring members arranged to expandingly engage the piston ring.

One of the objects of my invention is toprovide an improved piston ring expander of the l0 foregoing character which is simple in construetion, is easy to install, and which ishighly eilicient and durable in use.

Another object is to provide a piston ring expander wherein the spring members include lspringarmsconstructedandarrangediioiiex uniformly throughout their length thereby insuring longer spring life and a uniform ringexpanding action.

A more specific object is to provide a piston l ring expander of the foregoing character whereinthespringarmsareeachsupportedatcne end with the other end free and adapted to engage the piston ring, the ends of the spring arms being of substantially the width of the support- I ing band with the intermediate portions of the arms reducing in section from their supported ends toward their free ends.

Other objects and advantages will become apparent as this description progresses and by ref- I0 erence to the drawing, wherein,

A Figure l is a fragmentary perspective view of one form of piston ring expander embodying my invention;

Fig. 2 is a sectional plan view of a piston show- 3l ing the expander in position behind a piston Fig. 3Qis a fragmentary perspective view of another form of piston ring expander embodying my invention; and

40 Fig. 4 is a view 'similar to Figs. 1 and 3 illustrating still another form of expander embodying my invention.

The expander shown in Fig. 1 includes a supporting band Il and a plurality of spring mem- 5 bers II which may be integrally cut and formed from a sheet or ribbon of soft steel and thereafter heat-treated and tempered so that they become hard and resilient and have the characteristics of spring steel. The material from which the expander is formed may vary in thickness, for example, from .005" to .020", and the band is of a width approximately equal to the width of the ring groove in which it is to be mounted. 'l'helenthofthebandisslkhtly lestbantheclrcumferenceofthebottomofthe ring groove.

Thespringmembers II areconstructedand arrangedtooverlietheband llinspacedrelation. Bch spring member includes an intermediate portinn I2 of substantially the same widthastheband I0,thesamebeingconnected totbebandbyancck Il. Theintermediateportim Ilofthespringmembermpportsspring arms Il which extend in opposite directions in substantially parallel relation to the band. The supporting band Il, immediately back of the intermediate perdon I2 of each spring member, is provided with an embosment I5 which holds the spring member in spaced relation and supports the intermediate portion I2 of the spring member for the flexing action of the spring arms Il.

The spring arms Il are so constructed that, when they are assembled in operative relation to a piston ring, they will flex uniformly throughout their length from the intermediate portion of the spring members I2 toward the outer ends of the arms, thereby avoiding constant ilexng andbendingstrainsandstressesatanyonepoint therein and insuring longer spring life. 'I'his action is accomplished by shaping the spring arms so that 'they taper inwardly along both edges thereof from the intermediate portion of the spring member toward the outer end thereof, thereby gradually and uniformly reducing the section of the arms toward their outer ends. By thus reducing the section of the arms, their ilexing ability increas toward their outer ends and the arms tend to ilex lmiformly throughout rather than to hinge merely at the fulcrumsupporting intermediate part I2.

'l'heextremeouterendsofthespring arms Il are formed to substantially the full width of thesupportingband iisothatthearmsare substantially T-shaped. This construction permits engagement of the ends cf the arms substantially across the inner surface of the piston ring, thus reducing wear, minimizing cutting or "scuillng of the ring, and avoiding any tendency ofasprlngarmlltocausetheringtotiltor cock in the piston groove.

AsshowninFlg.2,theexpandermaybe mounted in a ring groove I1 of a piston-I0. It will be seen that the expander seats snugly against the bottom of the ring groove and that theringcontactingpoints I6 ofthespring arms Il engage the rear or inner surface of the piston ring I9. Bach spring member II operates independentlyoftheotherspringmembers, with the arms thereof freely engaging the inner surface of the ring with a minimum of friction; and, in this manner, the desired pressure characteristics of the ringI and the proper contact between the ring and thecylinder bore are assured. The ring expander may be used in connection with a ventilatedoilringand,inthatcase,thesllpporting band is provided with suitably located slots 2l fordrainingoilbackintothe crankeaseofthe-x l0 engine.

Other expander structures embodying my invention are shown in Figs. 3 and 4. The expander of Fig. 3 is similar to that previously described except that spring arms 2| are L-shaped,

ll providing outer end portions 22 of substantially the width of the supporting band 24 to avoid the tendency of such arms to dig into the piston ring. Also in this form (Fig. 3) the intermediate portion 23 of the spring member is of substan- N `tially the width of the supporting band Il and the upper edges of the intermediate portions of the spring arms 2| are tapered to reduce the section of such arms from the intermediate portion Il to the outer end 22 thereof.

In the form shown in 4, the spring arms 25, throughout their length, are of substantially the width of the supporting band 26, and the section' of these arms is reduced by providing in each thereof a slot 21. The slot 2111s of greater 3 width at the outer free end of the spring arm Il and reduces in -width toward the intermediate portion 28 of the spring member. Otherwise, this form is the same as the forms previously described.

35 rt will be understood that, although I have described several forms of my invention, other changes in details and arrangements of parts may be resorted to without departing from the spirit and scope of my invention as defined by 40 the claims that follow.

I claim:

1. A piston ring expander adapted to be mounted in a piston ring groove behind a piston ring comprising a supporting band adapted Il to seat in the piston ring groove, a plurality of spring members carried by said band and each having an intermediate portion of the width of said band and having spring arms extendhm from the opposite ends of said intermediate 50 portion and overlying the outer face of said band in spaced relation thereto, said spring arms being T-shaped and having their T-heads free and adapted to frictionally engage the inner surface of the piston ring, and the T-stem portion of il said arms adjacent the T-head thereof being of less width than said band and gradually and uniformly increasing in width away from said T- headY to said intermediate portion.

2. An integral piston ring expander comprisd ing a supporting band, a plurality of spring members carried by said band, each of said spring members including an intermediate portion of substantial length carried by said band and spring arms carried by and extending from opposite ends of said intermediate portion in overlying and vspaced relation to said band, neck portion extending throughout the length said intermediate portion and connected to adjacent edge of said band: said arms being constructed that their opposite side edges taper gradually and uniformly outward and inward 'fran said intermediate portion to the outer ends of said arms and the outer ends of said arms are substantially the same width as said intermediate portion and band.

sen

thereof tapering inwardly from said intermedilo` ate portion toward but short of their outer ends which are of substantially the same width as said band. the lower edges of said arms extending along in substantially edge alignment with the lower edge of said band. i6

4. A piston ring expander comprising a supporting band, a plurality of spring members carried by said band and having spring arms overlying tbe outer face of said band in spaced relation thereto, said spring arms being of substantially the same width throughout with the opposite side edges thereof substantially aligned with the opposite side edgs of said band. and each of Isaid arms having a longitudinal slot therein extending from near one end thereof to near the other end thereof and which decreases in width from the outer end of said arm toward its other end to reduce the cross-sectional area of the material of each arm toward its outer end.

5. An integral piston ring expander which in- 80 cludes a supporting band adapted to be mounted in a piston ring groove behind a piston ring therein, a spring member having an intermediate portion of substantial length and of a width throughout substantially equal to the width of said band, a neck portion extending substantially the length of said intermediate portion and supporting the latter from one edge of said band.

similarly-shaped spring arms carried by and extending from the opposite ends of said intermediate portion in overlying spaced relation to the outer face of said band. said spring armsl being so shaped that their outer ends are of substantially the width of said band, neck and intermediate portion, and the cross-sectional area of each said arm is gradually` and uniformly reduced from said intermediate portion to the outer end thereof.

6. A piston ring expander adapted to be mounted in a piston groove and behind piston l0 ring structure therein, the expander comprising a plurality of thin spring expanding members of substantially uniform radial thickness, circumferentially spaced apart and adapted to operate substantially independently of each other and 55.

each expanding member having a wide intermediate portion adapted to cooperate with the back of the piston groove, and end portions substantially of the same axial width as the intermediate portion and adapted to engage the ring struc- 00 ture, the cross-sectional area of each member being gradually and substantially uniformly reduced axially from its said intermediate portion to its said end portions, to permit substantially uniform flexing from the intermediate portion 66 to the end portions.

, 7. An integral piston ring expander adapted to be mounted in a piston groove behind piston ring structure therein, the expander comprising a plurality of thin spring expanding members 'l0 clrcumferentiaily spaced apart, and means for connecting the members, each of said members having an intermediate portion approximately as wide as the width of the piston groove and adapted to exert pressure against the back of.

the piston groove and end portions oi' substantially the same width as the intermediate portion and adapted to engage and exert pressure against the ring structure, and each member also having edge recesses of gradually increasing depth from the intermediate portions to the end portions to permit substantially uniform exing from the intermediate portions to the end portions.

8. An integral piston ring expander comprising a supporting band, said supporting band being adapted to engage the bottom of a ring groove and having a plurality of oil drainage passageways extending therethrough, a plurality of spring members carried by said band, each of said spring members including an intermediate portion of substantial length and o! substantialiy tbe same width as said band carried by said band andy spring arms carried by and ex-` tending from opposite ends of said intermediate portion in overlying and spaced relation to said band, the outer end portions of said spring arms being of substantially the same width as said intermediate portion a neck portion extending substantially throughout the length oi' said intermediate portion and connected to the adjacent edge of said band, said spring expanding members being of substantially uniform radial thickness and being gradually and substantially uniformly reduced axially from said intermediate portion to said end portions, whereby to permit substantially uniform flexing of said arm from said intermediate portion to said end portions.

FRED H. GIVEN. f

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