US2325196A - Piston ring - Google Patents

Description

July 27, 1943. E BRQTHWEILER 2,325,196

PISTON RING Filed Jan. 15, 1940 2 Sheets-Sheet l July 27, 1943 E. B. ROTHWEILER PISTON RING Filed Jan. l5, 1940 2 Sheets-Sheet 2 Mv /I/A Patented July 27, 1943 PISTON RING Edward B. Rottweiler, st. Louis, 'Mo.,

assigner to Coil Piston Ring Company of America, St. Louis, Mo., a corporation of Missouri Application January 13, 1940, Serial No. 313,646 3 Claims. (Cl. 309-45) This invention relates to piston rings.

An object of the invention is to provide an improved piston ring made of a coiled strip or coiled strips of steel of approximately uniform thickness throughout its or their length and including outer and intermediate convolutions having their outer edges on approximately uniform radii of curvature, the outer convolutions having approximately flat sides throughout their circumferential length, and the intermediate convolution being arched or bent laterally in a direction approximately parallel with the axis of the ring to provide oppositely extended contacting portions for contacting with the inner surfaces of the side convolutions to hold the side convolutions in spaced relationship and to provide openings or oil drainage passages through the ring between the outer and inner convolutions.

Another object of the invention is to provide an improved piston ring comprising a plurality of convolutions of coiled steel, the outer convolutions being approximately flat throughout. their circumferential length and having their ends terminating at relatively short distances from laterally extended portions integrally uniting the outer convolutions with the intermediate convolution, the intermediate convolutions being arched or bent laterally to provide a cellular structure between the outer convolutions, affording spaces for oil drainage when the ring is under compression on a piston within a cylinder.

Another object of the invention is to provide an improved piston ring including a coiled strip of steel of approximately uniform thickness having an intermediate convolution provided with laterally bent arch formations of novel arrangement so that, when the ring is under compression within a cylinder, the points of the arches are within the radius of curvature of the remaining portion of the ring, thereby preventing the points of the arches from scoring or marring the inner surface of the cylinder when the ring is mounted on a piston therein for use.

Various other objects and advantages of the invention will be apparent from the following description, reference being made to the annexed drawings, in which- Fig. 1 is a perspective view of a unitary piston ring made in accordance with this invention and distended in order to show the arch formation of the intermediate convolution.

Fig. 2 is a side elevation of the piston ring in its natural form before being compressed within a cylinder.

Fig. 3 is a sectional view of the piston ring mounted on a piston within a cylinder.

Fig. 4 is a side elevation of a slightly modified form of the ring shown in Fig. 2.

Fig. 5 is a perspective view similar to Fig. 1 showing a piston ring composed of two convoluted sections of coiled steel strip.

Fig. 6 is a perspective View of a piston ring, distended as in Fig. 1, showing a modified form of the invention.

Fig. 7 is a side elevation of the piston ring of Fig. 6 in its natural form before being compressed within a cylinder.

Fig. 8 is a sectional view of this form of piston ring mounted on a piston within a. cylinder.

Fig. 9 is a side elevation of a ring having additional offsets connecting the side convolutions with the intermediate convolution and elongated supports for the end portions of the side convolutions.

Fig. 10 is a distended perspective view of a piston ring in whicllli one of the side convolutions is unattached to t e intermediate convolution and provided with means coacting m'th the intermediate convolution to limit extent of relative turning movements of the two parts of the ring.

Fig. l1 is a side elevation of the ring that is shown in Fig. 10.

The piston ring shown in Figs. 1 and 2 is made of a strip of fiat steel rolled or coiled to form a number of convolutionsl including two at side or end convolutions I and 2 and at least one intermediate convolution having integral connection with the end convolutions and provided with an annular series of lateral arches or bends extending in a direction approximately parallel with the axis of the ring to provide oppositely extended spacer portions. The intermediate or spacer convolution of the unitary ring shown in Figs. 1 and 2 includes the circumferentially elongated arch portions 3 for contacting the convolution I, and the circumferenti'ally elongated arch portions 4 for contacting the convolution 2, and connecting means 5 integrally uniting the arch portions 3 and 4. In this form ofthe device, the dat convolution I is integrally united with the arch portion 3 at the adjacent end of the intermediate convolution by an integral connection 6 inclining laterally from the arch portion 3 to the convolution I, The attached end of the convolution I is offset laterally from the part 3 a distance approximately equal to the thickness of said convolution I so that, when the ring is placed within the piston ring groove 1 (Fig. 3), the outer side of the convolution I is pressed against one of the side walls of said groove.

The attached end of the outer convolution 2 is integrally'united with the adjacent end of the portion 4 by a lateral bend 8 similar to the connection 6 so that, when the ring is compressed in a piston groove, the entire outer surface of the convolution 4 contacts with one wall of said groove. A ring of this construction provides a circumferential series of openings or oil drainage passages 9 between the inner and outer convolutions of the unitary ring. In the slightly varied form of the ring shown in Fig. 4, the attached ends of the flat outer convolutions I and 2 are integrally connected with the adjacent ends of the arched inner convolution by integral uniting portions I and II. The length of the connecting portion Il) is equal to the combined length of the connecting portion `6 and the adjacent connecting portion and the length of the connecting portion II is equal to the combined length of the connecting portion 8 and the adjacent connecting portion 5. This arrangement eliminates the separate bends providing the spaced connecting portions 6 and 8 of the ring shown in Fig. 1.

'I'he two-piece ring shown distended in Fig. 5 is made of two sections of a fiat steel strip rolled or coiled to form a number of convolutions including two flat side or end convolutions I and 2 and at least one intermediate convolution having integral connection with the end convolutions, respectively. A part of the intermediate convolution is integrally connected with each of the side convolutions, and the adjacent ends of said intermediate convolution have laterally extended abutments I2 which prevent the arch portions 3' from becoming overlapped or sliding one beyond the other when the ring is placed in the ring groove 'I of the piston. With the exception that the ring shown in Fig. 5 is made in two parts and includes the abutments I2, said ring is the same as that shown in Fig. 1. The abutments I2 extend laterally toward the adjacent side convolution to cooperate with the connections 5' in spacing the side convolutions I' and 2. A

The ring shown in Figs. 6 and 7 is made of a strip of fiat steel coiled to provide two flat side or end convolutions I3 and I4 integrally connected with an intermediate convolution having an annular series of lateral arches or bends to hold the side or end convolutions properly spaced. The intermediate or spacer convolution of this unitary ring includes a number of circumferentialiy alined relatively long at portions I5 for contacting one `of the side convolutions and integrally connected by relatively short arches or bends I6. The bends or arches I6 are wider at the outer periphery of the ring than at the inner periphery of the ring and are shaped and formed in such a manner that, when the ring is under compression within a cylinder, the outer peripheral portions I'I of said arches are in continuous annular alinement with the outer periphery of the composite ring and do not extend outwardly beyond the outer periphery of any portion of the ring when the peripheries of the convolutions I3 and I4 and of the elongated portions I5 of the inner convolution are even with each other. This relationship may be attained by dying the intermediate portion of the unitary ring to compress or force the arches I6 slightly inwardly toward the axis of the ring to provide the necessary tolerance required to obtain the relationship shown in Fig. '1, in which the outer peripheries of all of the ring segments or convolutions are on the same radius of curvature. Specifically, for the attainment of this relationship, the arches I6 may be made wider at the outer periphery of the inner convolution than at the inner periphery thereof, and also of slightly greater depth as shown in Fig. 6.

The side convolution I3 is integrally united with the adjacent end of the inner convolution by an integral connection I8 inclining laterally from the elongated portion I5 a distance equal to the height of the adjacent arch I6 plus the thickness of the ring material. By this arrangement, the outer surface of the outer convolution I3 is in the same plane when the ring is compressed as shown in Fig. '7, which is its position when mounted in a piston groove. Similarly, the outer convolution I4 is united with the ad1 jacent end of the inner convolution by an integral connection I9 inclining laterally from the portion I5 a distance equal to the thickness of the strip of which the ring is composed so that, when the ring is tted in a piston groove, the outer surface of the convolution I4 is uniformly in the same plane. A ring of this construction includes circumferential series of openings or oil passages 20 and 2| between the inner and outer convolutions of the ring. In the slightly varied form of this unitary ring shown in Fig. 9, the lateral extension 22 is equal to the height of the `arches I6 and has a circumferentially extended portion 23 to constitute a side rest or bearing for the end of the convolution I3. The convolution I3 is integrally united with the extension 23 by a portion 24 extending laterally a distance equal to the thickness of the ring material.

In the two-piece ring shown in Figs. 10 and 11, the convolution I4 is integrally united with the inner convolution by an offset bend 25 extending laterally a distance equal to the height of the arches 26 plus the thickness of the metal so that, when the ring is compressed as in Fig. 11 with the outer convolution I4' against the arches 2B, the outer surface of said outer convolution is in the same plane throughout. 'Ihe opposite end 2'I of the inner convolution is separated from the connection 25 a suilicient distance to receive between said parts a laterally bent portion 28 formed diametrically opposite from the ends of the separate outer ring portion 29 which, when the ring is assembled, seats against the circumferentially elongated parts 30 of the intermediate or spacer convolution. When assembled as shown in Fig. 11, the bend 28 extends substantially into the space between the connection 25 and the end 21, and thereby limits extent of relative turning movement of the two ring parts.

Each specific embodiment of the invention disclosed is composed of coiled thin steel of uniform axial thickness and uniform radial width throughout, and includes two outer annular portions each of less length than a complete annulus and each having lts outer surface in a single radial plane throughout its circumference. A spacer convolution is located between and may be integrally connected with one end of each of said outer portions as in Figs. 1 and 6, or with only one of said outer annular portions as in Fig. 10. In each embodiment, the spacer convolution comprises an annular series of arcuate circumferentially elongated at segmental portions curving transversely on the saine radius of curvature as said outer portions and each having one fiat side bearing throughout its length against the inner radial surface of one of the outer portions. These elongated at segmental portions that curve transversely on the same radius of curvature as the outer portions are indicated by l (Fig-1) by l (Fig. 6), and by 3i! (Fig. l0).

' An annular series of arches 3 5 iFig. 1), ll-IG (Fig. 6), yand 26 (Fig. 10) integrally connect the respective segmental portions and contact at spaced intervals with the radial inner side of the other outer portion of the ring. 'I'he sides of these respective arches converge from the segmental portions and are of relatively much less length than the circumferential length of said segmental portions, and the arches thus provided cooperate with the elongated segments of the spacer convolution to hold the two outer annular portions of the ring in spaced. relationship. By making the spacer convolution of elongated fiat segmental portions integrally connected by arches; less material is required than would be required if the arches were close to-'- gether and the elongated segments were omitted. Further, by providing the arches with sides that converge from these segmental portions, maximum resiliency is obtained to facilitate tting the rings in the piston grooves. The resiliency 'is greater than if the sides of the arches extended at right angles to the elongated at portions.

Either form of the invention as disclosed in the drawings is adapted for use on a piston having the piston ring groove l therein. When the ring is mounted in the groove l, the outer surfaces of the outer annular portions of the ring are pressed into close sealing contact with the side walls of the groove and the peripheral portions of all ring convolutions will be pressed against the wall of the cylinder 3l and prevent the passage of gas from the combustion chamber and also prevent the passage of oil into the combustion chamber of the engine. An expanding ring 32 to cooperate with either specic form of piston ring disclosed may be mounted within the piston ring groove l. The combined thickness of the several convolutions, including the arches or bends on the spacer convolution, is slightly greater than the width of the groove 1, so that the entire composite ring must be slightly compressed in order to enter the groove.

The invention may be varied in other specific forms without departure from the nature and principle thereof.

I claim:

1. A multiple piece piston ring composed of a plurality of coils of thin steel and including two outer annular portions each of less circumferential length than a complete annulus having their outer surfaces in single planes throughout their circumferences, a spacer convolution of less circumferential length than a complete annulus unattached to one of said annular portions and having integral connection with the other and having a circumferential series of lateral arches holding said annular portions in spaced relationship and forming passages, and means preventing substantial turning of said unattached annular portion with respect to said spacer convolution and leaving said two outer portions free to expand and contract during movement of the piston on which they are mounted.

2. A. piston ring composed of coiled thin steel of uniform axial thickness and uniform radial Width throughout and including two relatively unattached outer annular portions each of less circumferential length than a complete annulus and each having its outer surface in a single radial plane throughout its circumference; a spacer convolution integrally connected with one end of only one of said portions and unattached to the other and comprising an annular series of arcuate circumferentially elongated ilat segmental portions curving transversely on the same radius of curvature as said outer portions and each having one at side thereof bearing throughout its length against the inner radial surface of only one of said outer portions, and an annular series of arches integrally connecting said segmental portions and contacting at spaced intervals with the radial inner side of only the other outer portion of said ring, the sides of said respective arches converging from said segmental portions and being relatively of much less length than the circumferential length of said segmental portions, and said spacer convolution thereby holding said two outer portions of the ring in spaced relationship.

3. A piston ring composed of two relatively unattached coils of thin steel of uniform axial thickness and-*uniform radial width throughout their lengths, each being of less circumferential length than a complete annulus, and each having its inner `and outer surfaces in single flat radial planes throughout its circumference; a spacer convolution between said two coils integrally attached to one of said coils and unattached to the other coil and comprising an annular series of arcuate circumferentially elongated ilat segmental portions curving transversely on the same radius of curvature as said two coils and each having one at side thereof bearing throughout its length against the inner nat radial surface 'of one of said coils, an annular series of laterally extended arches integrally connecting said segmental portions, said arches engaging the inner ilat radial surface of the other coil and holding said coils in spaced relationship and cooperatsides of said respective arches converging from and being relatively of much less length than the circumferential length of said segmental portions, and means preventing substantial turning of said unattached coils with respect to each other and said spacer convolution.

EDWARD B. ROTHWEILER..

Images