I Aug.'20, 1940. IA. W.1WENZEL 2,212,336:
' PACKING RING Filed Jun 29, 1937 55 2 INVENTOR ALBE/PrW W/VZEL Patented Aug. 20, 1940 UNITED STATES PATENT oer-ice PACKING RING Application June 29, 1931, Serial No. 151,043
This invention relates to packing rings, and more particularly to packing rings of the metallic type as generallyemployed in connection with reciprocatingpistons in cylinders, such as in- 5 ternal combustion engines.
, The objects of the invention are to provide a packing ring having improved characteristics, greater sealing power, and longer life; to employ f the pressure'within the cylinder as a means for 10 counteracting wear of the ring; to counteract v uneven wear of the ring against the cylinder wall; to apply a moment of force against the outside periphery of the ring during periods of usewhen the ring would otherwise be under influence of 15 an opposite distorting moment of force; to provide means for automatically balancing the opposed force for maintaining the ring in its circular condition; to avoid any weakening effects of structures at the part of the ring where greatest 20 strength is required; to utilize the cylinder pressure to maintain the ring seated against the far side of its groove; to securesimplicity of construction and operation: and. to obtain other advantages and results as may be brought out in the 25 following description.
Referring to the accompanying drawing in which like numerals of reference indicate similar parts throughout the several views:
Figure 1 is a sectional view longitudinally and 30 diametric toa cylinder and piston in which the present invention is mounted;
Figure 2 is a plan vlew of a ring according to the invention;
Figure 3 15 a sectional view of a portion of the w 35 cylinder and piston and of the ring of the present invention with the mid part thereof broken away and upon a largerscale than shown in Figure l;
. Figure 4 is a sectional view corresponding to Fig. 3, but showing the ring only and of a modi- 40 fled construction with the differential feature omitted; and
Figure 5 is a similar section wherein the differential feature is included in modified form.
In the specific embodiment of the invention 4 illustrated in said drawing, the reference numeral l indicates a portion of an engine providing cylinder ll within which may be reciprocated a piston l2, the cylinder being closed at its com- 7 wall or circumference.
the invention is not limited to internal combustion engines, as it is likewise applicable in connection with other types of engines all of which have the common attribute of providing a motivating medium under pressure within the compression end of the cylinder by which the piston is impelled toward the crank case end thereof.
For purposes of illustrating the present invention, a piston is illustrated in Fig. l as having 10 ring receiving grooves l5 and H5 in its outer It will be observed that these ring receiving grooves are different in shape, the cross-section of one being rectangular and the other being trapezoidal. However, the shape of either groove or both grooves may be changed or their situations reversed or altered or other grooves provided in greater or less number as found desirable.
For purposes of the present description, a ring i1 is shown in the rectangular shaped groove l5, and Figure 2 may be considered as a plan of this ring. It will be understood, however, that a v plan of ring l8 shown mounted in the trapezoidal l1 and has therefore not been specifically illustrated in a separate view.
It has been found in practice that all piston rings, both new and after a period of service, not only require but actually have a clearance between their fiat faces and the flat faces of the ring receiving grooves. This clearance is an unavoidable necessity to accommodate freedom of movement of the ring to move in a radial direction and to obtain the desired resilient expansion moment of force inherent in the ring structure to engage the ring tightly against the cylinder wall. The present ring is similarly resilient and expansive to engage the cylinder wall and as to clearance between its fiat faces and the flat faces of the receiving grooves fulfillingvrequirements of present day specifications and requirements of use for giving the necessary freedom ofmovement of the ring to perform its sealing function. The clearance heretofore provided and as also provided in the present disclosure results in a proportion of the compression created in the compression end of, the cylinder to leak through to the inner circumference of the ring into the spaces between the bottom of the grooves and said inner circumference of the ring. The compression thus passed into the bottom of the grooves exerts a moment of force against the ring tending to expand it. A careful study of theeffect of this force shows that it has hereforce above described and thus have greater.
frictional .contact with the cylinder wall and wear down more rapidly than portions of the outer circumferential surface of the ring remote from the split. V According to the present invention I provide means for exerting va counteracting force exerted radially inward upon the outer circumferenceof the ring in the region where greatest wear has heretofore been observed. This counteracting force will therefore tend to reduce the frictional engagement of the ring in the region of the split against the cylinder and will'thus reduce the wear on the outer cylindrical surfac at that region. 1 h
In carrying out the invention, and describing the same with regard to the specific showing in Figures '1 and 3 of the drawing, the outer cir; cumference of the ring is preferably stepped back,
as at, 20, from the cylinder engaging circumferential surface 2| of the ring so as to provide an groove ii "of Fig. 1 havingitrapezoidal crossthe fluid pressure in the cylinder. This stepped portion 20 of theringis preferably of a differential character, that is to say, provides a progressively decreasing area as it recedes from the split of the ring. One convenient mode of'manu-.
facture comprises cutting a tapered shoulder eccentrically with the deepest part of the shoulder at the side of the ring having the split and the less deep part ofthe shoulder at the part of the ring diametrically opposite from the split. The shoulder therefore, in a direction parallel to the axis of the ring has a considerable depth next the split of the ring, that depth progressively decreasing as indicated byline 22 as the shoulder goes around the ring in both directions from the split as far as the diametrically opposite part of the ring. Thus it is that thepressure in the cylinder will have greater area and therefore characters for like parts are employed except greater effect upon the ring next the-split than it will have at points at a distance from the split. By proportioning the depth-of theshoulder next the split, to the extra force required to overcome the force exerted at thejinsicie" of the ring at that point, the ringcan be maintained circular and with the same frictional contact of its cylinder engaging; surface, 2'i'all the way around the ring. The fiexingaofzthe ring next its ends or joint is likewise greaterbecause' more Y metal is removed them 'thanata distance from o changes as well as combinations of disclosures,
the joint. ,s'
As shown in connection wit the ring receiving section, afringffi l is provided having correspondingly sloped :iil'at faces, butotherwise ring 18 likewiseprovides an inset ,f'or stepped circum ferential portion 20' which progressively decreases in'area from the split 18', as upon line 22',
so'as to obtain the above described equalization of pressure and wear upon the cylinder engaging outer circumferential surface 2| of this ring., Plan. of this ring. is identical with the plan of the previously described ring, Fig. 2,
The construction of groove [8 and ring it with tapered side walls enables the ring to seat with minimum gap permitted between the ring and cylinder wall and will reduce the blow-by" of high compression in the cylinder operating against the stepped portion. It is not the purpose of the invention to provide suflicient area of the stepped portion to force eitherring out of engagenient with the cylinder wall, but merely to counteract a portion of the pressure against the cylinder wall represented by the pressure within the groove in excess of the normal resilient pressure. exerted by the inherent resiliency of the ring itself. -It therefore follows that the ring 11 in groove i5 having-parallel walls will function to accomplish the purpose of the invention under normal operating pressure within the cylinder, but sometimes the normal pressure is raised to considerable higher than normal, and
in such instances the use of a ring with tapered Said showing-indicates a ring 23 having side faces 24, 25 (here shownparallel) and a circumferential cylinder-engaging surface 26 of less depth than the over-all'depth of the "ring; This ring also provides an inset or stepped circumferential area 21 which slopes backtoward the compression edge so as to be accessible to the cylinder compression. Preferably thesloping back begins at a radial distance inward', from the cylinder engaging surface -24"'thereby" providing a; ledge v 28 perpendicular, to the 1 cylinder engaging surface and parallel to the side faces 24, 25 of the ring. This construction enables the cylinder compression't'o act squarely against the ledge and seat the lower face of the ring firmly upon. the side face of the ring receiving groove. counteract, the tendency of the ring to lift from its seat as the piston slides down the cylinder in frictional cont'act therewith. The provision of the ledge entirely around the ring obtains a positive seal and avoids a'wedging of the compression gases between cylinder wall and ring. The foregoing description of Fig. 4 vapplies equally as to Fig. 5 wherein the same reference for addition of prime marks thereto in Fig. 5. Figure 5 differs from the showing of Fig. 4 merely in the fact that the sloping inset or stepped area 21' is shown eccentric with respect such as the difl'erential of depth of the'sloping portion of the outer circumference of Figures 1, 2 and 3 with provision of a circumferential ledge of either Figure 4 or Figure 5, and limita- I claim: 1. A packing ring having a steppedportion next one circumference of the ring and facing Thus the compression may be used to' .tion of the invention is contemplated only insofar I as recited in the following claims when construed I. r in the light of the prior art.
in the direction of said circumference. said R aaiaass stepped portion having maximum area immediately adjacent the split and decreasing from the same as a maximum to a minimum opposite the split within a segment of substantially 180 of the ring. I
2. A packing ring having a transverse split at one part thereof and having a stepped portion next one circumference of the ring and facing in the direction of said circumference, said stepped portion tapering in depth and having greatest depth next said split. r 3. A packing ring having a split and having parallel side walls and outer and inner circumferential walls of which one is for making a sliding seal in use, said ring having a stepped and tapered portion reducing the surface area of the said one of the circumferential walls for snaking sliding seal in use thereby providing a stepped back tapered surface for receiving a diil'erential pressure thereon tending to lessen pressure toward the sliding seal, said ring having an inherently greater resistance to flexing progressively from the slit through a distance of 180 therefrom. a
4. A packing ring having a cylinder-engaging circumferential surface and having a stepped and tapered circumferential surface entirely around the ring, said ring likewise providing a ledge between said circumferential surfaces and normal to the outer one thereof, said circumferential-surfaces being eccentric with respect to each other and said ledge extending entirely around the ring at the outside thereof and of varying radial width.
AHBERT W. WENZEL.