US757214A - Piston-ring. - Google Patents

Description

PatentedApril 12, 1904.

'lliairEn STATES PATENT OFFICE.

DONALD BARNS MORISOFLIOF HARTLEPOOL, ENGLAND.

ASPECIIEICA'I`IO1\T forming part of Letters Patent No. 757,214, dated April 12, 1904.

Application filed February '7, 1903. Serial No. 142,394. (No model.)

To' all wlwm/ it may concern:

Be it known that I, DONALD BARNs MORI- soN, a subject of the King of Great Britain and Ireland, and a resident of Hartlepool, in the county of Durham, England, have inventcertain new and useful Improvements in and Connected with Piston-Rings, of which the following is a specification. I

It is found in practice, particularly with steam or gas of very high pressures, nthat the pressure acting on the inner circumference of .piston-rings causes excessive friction between the outer circumference of the piston-ring and the cylinder-walls and a consequent wearing away of the material of the cylinder or the ring, or both. It is also found-that if a piston-ring tits a cylinder accurately very little lateral pressure is necessary irl order to obtain the desired steam-tightness. i.

My invention relates to a device for limiting the expansion of piston-rings to a certain predetermined amount; and it consists ofv a Apreferably fiat ring which is received within a recess in the `piston ring or. rings or partly in a recess in the ring and partly in the junkvpiston-ring causes the outer surface of the ring to wear this wear continues only up to that point when the external diameter of the shoulder on the piston-ring is equal to the in- `terior diameter of the limit-ring, and as the limit-ring causes the piston-ring to wear uniformly on its outer surface and tends also to lmaintain the cylindricity of the piston-ring itis found that the accuracy with whichl the piston-ring fits the cylinder when the limit of vwear has been reached is such that not only is the leakage of steam minimized, but thev friction between the ring and the cylinderwall isalso minimized, thereby increasing the further expansion of the piston-ring is desired, the limit-ring is removed and its inner diameter increased by filing or otherwise. In order to facilitate increasing the diameter, the inner surface of the limit-ring is reduced-as, for example', by means of a groove-so that the surface to be filed is lessened.- This' reductioni'of the surface is an important feature, as it re uces the time necessary to make the adjustment. It is eyident that the adjustment may also be obtained by decreasing the diameter of the shoulder forming the recessv in the piston-ring.

Another feature of practical value in my invention is that facilities are afforded for obtaining exactly the adjustment required, as if the piston-ring is placed within the cylinder and the amount of the opening at the division of the ring noted the piston-ring may then be removed fromthe cylinder and the inner diameter of the limit-ring so adjusted that when the limit-ring is placed in the recess of the piston-ring the amount of opening at the divisionof the piston-ring can be accurately measured and the'hn'iit of expansion determined.

'My invention is applicable to various forms and types of piston-rings, and' is also particu# larly suitable for the rings of piston-valves.

In the accompanying sheet of drawings, Figure 1 shows, .partly in section, a piston-ring and a limit-ring constructed in accordance with and embodying my invention. AFig 2 represents the said piston-ring vand limit-ring as inserted into a piston. The piston-ring, limit-ring, and part of the piston are shown in section. Fig. 3 is a lsimilar -sectional view showing the piston illustrated in Fig. 2 placed within acylinder, for sake of simplicity only a part of the cylinder-wall being shown in secl tion. Fig. i is a sectional view of a piston provided with three'piston-rings and three limit-rings, the piston-rings being separated. by suitable distance-rings.` Fig. 5 is a sectional view of a piston placed within a cylinder, the piston-ring being provided with two limit-rings; and Fig. 6 is a similar view to Fig.

5. In this modification, however, the limitrings are placed partly' Within a recess of the roo piston-ring and partly within a Arecess of the piston-body or piston-cover, respect1vely.

Similar` letters of reference refer to slmilar parts throughout the several figures.

The piston-ring a, Fig. 1, is provided with a limit-.ring which is placed within a. recess' a of the piston-ring. The limit-ring encircling the projecting lip or shoulder a2 of the piston-ring limits the expansion of the pistonring to a predetermined amount.

The arrangement of piston-rings within pistons is well known and may be effected in varions ways. If, for example, a piston consisting of a body L', Fig. 2, a cover (i, and a piston-ring ci, provided according to this invention with a limit-ring b, is placed within a cylinder w, Fig. 3, the cylinder-wall compresses the piston-ring inthe' manner shown in Fig. 3. In' this position the exterior diameterof the shoulder` a2 is smaller than the interior'diameter of the limit-ring I). The wear of the outer circumference of the piston-ring gradually reduces thisdiference until the lip or shoulder a2 of the expanding piston-ring bears upon the interior rim or edge of the limitrin g. When the piston-ring has expanded into Y this position, the piston-ring held or secured `against further expansion by its limit-ring fits the cylinderaccuratcly. This is of great practical importance, as a piston working as `it generally does in high-pressure steam or gas is very liable to be adversely affected by the consequent friction, the desired steam or gas tightness being obtained at the same time by the said accurate or snug fitting of the piston-ring. The modification illustrated in Fig. 4c shows a plurality of piston-rings a, separated by distancerings-c and provided with limit-rings b. Fig. 5 shows likewise a section of a piston, provided between its body and junk-ring or cover d with a piston-ringf, acted uponby` suitable springs e and encircled by two limitrings b. The limit-ring mayv also be placed partly within a recess of the piston-ring and partly in a recess of the piston, as will be seen in Fig. 6, in which the limit-rings arc each in a recess formed partly in the piston-ring and partly in the body or cover respectively. .ln this'cxample the piston-ring consists of two parts y, which are separated by springs L.

.In order to facilitate increasing the diameter, the inner surface of the limit-ring is reduced by means of a groove b', so that the surface to-be filed is lessened. y

Having fully described, my'invention, what I claim, and desire to secure by Letters Pat#v flat faces and continuous rings encircling the shoulders` to limit the expansion of the split rings, substantially as and for the purposes set forth.' 1

4. The combination with apiston and its cover, of a piston-packing between them and an independent continuous ring of less diaml eter .than the bore of the cylinderfinto which the piston fits to surround a portion of the packing andlimit its expansion, substantially as set forth.

5. The combination with a piston and its.

cover, of a packing-ring having a lateral shoulder and a continuous rlng having a thickness about equal to the height of the shoulder, and

su'rroundingit;` and a groove cut in the inner circular face of the said continuous ring, substantially as and for the purposes set forth.

G. The combination with a piston having a ,.body, a cover and' a peripheral groove, one

wall of which isforrned by the cover and the opposite wall in the body, oppositely-situated circular grooves in the opposite walls ofthe periphe'ralgroove in the piston, an eXpa-nsible packing in the groove in sa'idpiston having grooves on its opposite faces anda continuous ring lying partly in a groove in the pack'- ing and partly in a grooveI in a side wall of -the peripheral groove of the piston, .substantially as described. v

DONALD BARNS MORISON. Witnesses:

l. HARRY TILLY, Jr., .Jol-[N BfS'raovsR.

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