US1008999A - Metal packing-ring. - Google Patents

Description

R. B. WASSON.

METAL PACKING RING. APPLICATION FILED JULYZQ, 1910.

1,008,999, Patented Nov. 14, 1911.

2 SHEETSSHEET 1.

witmeoaeo Suva/W 50i R. B. WASSON. METAL PACKING RING. APPLICATION FILED J'ULY 29,1910.

Patented Nov. 14, 1911.

2 SHEETS-SHEET 2.

ROBERT B. WASSON, 0F CRANFORD, NEW JERSEY.

METAL PACKING-RING.

To all whom 'it may concern:

Be it known that I, ROBERT E. W'assox, a citizen of the United States, residing at Cranford, in the county of Union, State of New Jersey, have invented certain new and useful Improvements in Metal Packing- Rings, of which the following is a specificat-ion.l p

This invention relates to metal packing rings.

The packing rings constructed in accord-' ance with this im'ention are either in the nature of piston rings. which exert an outwardradial pressure, or stufling box rings,

which exert an inward radial pressure. The

rings are of that kind in which the radial pressure is due to the resiliency of the metal of the ring, and not to external springs.

Among the objects of'the present invention are to provide a packing ring that will form as nearly as possible an absolutely tight joint both with the part carrying it and with the part with which it has slidable contact. to render the radial pressure of the ring uniform at all points circumferentially thereof. to minimize the amount of clearance or space between the ring and the walls of its retaining groove when in working condition. so as to minimize the accumulation of oil. etc., to secure approximately the minimum equal radial pressure that will produce a gas-tight joint, thus reducing wear and friction and consequent loss of power. to secure an equal distribution of weight throughout the annulus so as to avoid the tendency of a plurality of rings under working conditions to localize or aline their slots, and to enable the ring to be produced in an economical manner.

l'i'ith these and other ends in view, the invention may be said to consist in the method and article hereinafter described and more particularly pointed out in the claims.-

been hammeredso as to cause the ends to separate; Fig. 4 is a side view of" Fig. 3;

Fig. 5 1s a panoramic view of a portion of the inner surface of the piston ring, showing semidiagrammatically the result of the hammering; Fig. 6 is'a sectional view showing the ring held in position to be hammered, and the hammer in position to de- Specificatiou of Letters Patent.

with my invention, I may,

cular both inside and out.

Fig. 3 is a' Patented Nov. 14, 1911.

Application filed July 29. 1910. Serial No. 574,495.

liver the blow; Fig. 7 is a front view of the lower part of Fig. (5; Fig. 8 is a plan view of the ring and the holder in which it is held while being gaged, and showing also in longitudinal section a suitable instrument for gaging the tension of the ring; Fig. 9 is a sectional side elevation of the parts, shown in Fig. 8; and Figs. 10 and 11 are sectional views showing the'completed piston ring seated in a groove in a piston and exerting circumferentiallyuniform radial spring pressure on the confining wall of the cylinder.

In making a piston ring in accordance and preferably do, first produce an annulus of cast iron or other suitable metal which is of the same cross-section throughout, and which is cir- Furthermore, this blank may be, and preferably is, of substantially the same external diameter as the bore of the cylinder and of substantially the same internal diameter as the bottom of the groove in thepiston in which it is to be seated. The order of the subsequent steps may be varied. In the particular form of now out or split the annulus, preferably at one point and preferably with a diagonal'cut. The annulus is preferably so cut that a minimum amount of metal is removed, that is, only so much is removed as is necessary to allow for thermal expansion and contraction while in use, say twenty thousandths of an inch. I now proceed to a most important step, which consists in mechanically and permanently distorting the structure of the inside surface portion of the metal ring. This operation results in spreading the annulus, so as to separate its ends, so that, in order to introduce the ring in position on the piston insidethe cylinder, it will be necessary to compress the ring back to its normal or original circular form; the ring will then exert a radial outward pressure that is due to the permanent distortion of the structure ofthe metal at the inner side of the ring. In other words, the permanent internal distortion of the structure of the superficial portion of the metal produces an external distortion of the annulus as a whole in the nature of an expansion or opening; so that the compression of the ring in the cylinder takes away this external distortion opposition to the permanent internal distort1on',thereby occasioning the outward spring of form and acts in y when the parts pressure. The distortion of the inner superficial region of the ring is preferably accomplished by hammering in the cold, and is preferably in the nature of a superficial compacting or compression of the structure of the metal along the inner circumference so as to produce a kind of compression spring action by the circumferential compacting of the particles of metal. If the material of the ring did not possess elasticity at the outset, the hammering operation gives it elasticity. The operation is so conducted that the degree. of distortion is varied circumferentially in a predetermined manner. Thus. the distortion is greatest at the central portion of the ring, opposite the cut, and thence diminishes in both directionsto the two ends, where it is minimum. The energy-of the blows used in hammering does not decreaseuniformly fromthe middle or uncut to the cut portion of the ring. It decreases at first slowly and then very rapidlv and then again more slowly. The superficial distortion is symmetrical or substantially so for both halves of the ring. By means of this graduated distortion of the inner superficial region of the ring I am enabled to secure an equal outward radial pressure at all points circumferentially of the ring. The hammering or distorting operation is so conducted as to leave the radial thickness of the annulus to all intents and purposes unchanged; so that the annulus, as before hammering, is of uniform cross-section throughout. When the ring so made is placed in its groove in a piston and compressed by the confining wall of the cylinder, it fills its groove all the way to the bottom, uniformly-all the way around, and preferably it is of the same internal and external diameter as before hammering, and has the same very slightly space between its ends, This space is just suflicient to allow for the differential thermal-expansion of the ring and piston, and is substantially closed heat up to the usual running temperature. Before the ring is put into use I prefer to grind it on the outer periphery and on the two sides, just sufliciently to insure a smooth j oint. The grinding may be done before the ring is cut or split. f

In making a stufiing box ring, I start with a blank which may be of cast iron such as I have already described. I now out asbefore, removing a minimum amount of metal. The hammerin is then performed on the outside of the rlng, instead of the inside, the

operation being otherwise the same. This hammering operation tends to make the ring contract with its ends'overlapped, so that when the ring is seated in its groove in a stufiing box or the like it exerts a uniform radial pressure inward on the shaft. In making a stufiing box ring, I may remove a very little more metal in the cutting operation than I prefer to do when making a piston ring, or else I may make the blank of slightly smaller diameter internally than the shaft or rod with which the ring is to make a tight, sliding joint; so as to insure that the abutting of the ends of the ring due to thermal expansion of the metal will not put an end to the inward pressure on the shaft. The grinding of the stufiing box ring to produce a smooth joint is performed on the inner surface and the two sides.

I prefer to perform the hammering operation with a hammer or striker having a narrow striking face as long as or longer than the width of the inner or outer face of the annulus. Preferably, the side faces of the striker converge, and the striking face is slightly curved transversely. One form.

of such a striker is shown in Figs. 6 and 7 In operation the striking face of the hammer is disposed parallel to the width of the inner or outer surface of the annulus being worked on.v I may so distribute the blows of this hammer that they overlap, producing a substantially continuous compacting along the length of the surface of the annulus; but I prefer to space the blows slightly, so

that the superficial portion of the annulus will be condensed in a series of parallel strips or lines. This distortion of the structure of the metal may have a. visible suggest-ion in-the nature of a slight ribbing or banding of the surface, as shown semi-diagrammatically in Fig. 5. This ribbing as a surface configuration is, however, extremely slight, there being preferably no appreciable distance between the high and low portions of the ribbing. The effect of the distortion produced in this manner, and also where the transverse lines of condensation are caused. to overlap, is confined largely or almost entirely to a circumferential direction; that is to say the effect of the blows on the metal may be said to comprise a radial component and a lateral component, and by my method I confine the lateral component to a circular or circumferential direction. In this way, the compacting of the metal is caused to yield maximum results in the wayrof'radial expansion of the ring when the latter is confined in use. Thus the hammering need never be so heavy as to produce appreciable alteration of the cross-section of thering.

While the hammering is being performed, I prefer to clamp or hold the two sides of the ring in sucha way as not to interferewith the hammering operationand to afford for piston rings is shown in Fig. 6, wherein 10 is a metal holder, 'sufliciently heavy for having an internal circular may be replaceable by seats of desired) for the peripheryof the purpose, seat 11 (which various sizes if the ring A, 12 is a fixed side clamping face on the seat 11 and 13 is a removable retaining ring, desirably threaded into the holder a complementary side 10, and affording clamping face. Thus, the outer and major portions of the two sides of the piston ring are clamped and the periphery is afforded solid support during-the hammering. The side clamping of the ring contributes to the minimizing of the sidewise spreading of the metal under hammering.

From time to time I may, and preferably do, age the result of the hammering. and

proceed with the hammering or cease ham mering accordingly. This testing'may be effected in a variety of ways. For purposes of illustration I have shown in Figs. 8 and 9, a holder :20 for a piston ring. ha ing an internal circular seat 'of thesame diameter as the cylinder bore which the ring A is to fit. The ring is slipped into this holder from time to time. and a pressure-indicating instrument such as indicated by the numeral 21 is pressed against the periphery of the portion or portions of the ring to be tested. The holder 20 may be provided with any suitable number of radial openings 2:2. through which the instrument 21 may be inserted against the periphery of the piston ring. The pressure-indicating instrument may be of any suitable nature. The device shown is of known construction. consisting of a barrel 23 through which slides a plunger 24: and in which is contained a spring 25 that opposes the rearward movement of the plunger. The plunger may bear pound graduations 26, to indicate the pressure at which the portion of the ring pressed upon yields from its seat in the holder 20. This is. of course, the same as the outward radial pressure exerted.- by this portion of the piston ring. In order that the operator may know when thepiston ring first begins'to yield, any suitable form of multiplying index or other indicator may be employed. For purposes of illustration, a bracket 30 rotatably mounted on the holder '20, normally locked by a nut 31 and carry.

ing a pivoted pointer 32 the short arm 33 of which in any position of the bracket 30 bears against the inner surface of the piston ring. The ring is tested from time to time during hammerlng, until an equal pressure is indicated at all points. The hammering is continued only until the minimum radial ring pressure, say five pounds, that will preserve a gas-tight joint, is produced. By means of this gaging stepImay perform the hammering of the packing ring entirely by hand and in an empirical manner. Or I may perform the hammering by a suitable machine automatically varying the'blowsby cam means designated according to the, particular size of ring and the particular metal employed. But even if the hammering be I have shown conducted in this manner, is useful since it enables variation in the metal of the same ring or difierent rings to be detected and compensated for by harder or softer hammering as the case may be. In fact one of the features of my invention is that I am enabled to insure uniform radial ring pressure by compensating for all variations in the metal of the ring.

A packing ring made according to my invention is of equal cross-section throughout. The feature of uniform cross-section is of primary importance. sinceit insures that the ring will notcnly form a tight joint with the cylinder wall (in case of a piston ring). but also with the piston that carries it, since the groove in the and filled all theway around.

Minimum clearance or spacebetween the ring and the bottom of its groove. produces a gas tight joint. The same is true, of course, with a stufling box ring, the carrier there being the inclosing part. Packing rings made according to my invention have their weight equally distributed, so that there is no tendency of two or' more rings in a piston or stufiing box to work to a position with their slots or cuts in series. The ring in use affords a uniform wearing sur face. One of the great features of the ring is that itexerts equal radial pressure at all points circumferentially. Moreover, by my method this pressure may be the minimum that will'maintain a gas-tight joint. I thus reduce wear and power loss, which are increased if the pressure is unnecessarily high at any or all points.

In Figs. 10 and 11 I have shown a piston ring A mounted in a customary peripheral groove -12 in a piston 40 and exerting uniform outward radial pressure against the wall of the confining cylinder 41.

Having thus described my invention. what I claim as new, and desire to secure by Letters Patent, is:

1. A metal packing ring consisting of a splitannulus of uniform cross-section, the metal of which is distorted along one of its curved sides in varying degree so as to cause the ring to exert uniform radial spring presthe gaging step sure.

2. A metal packin ring consisting of a split annulus of uni orm cross-section having the metal at one of its curved sides compacted in varying degree ranging from maximum at the region opposite the split toward minimum in both directions therefrom. a

3. A metal packing ring consisting of a split annulus of uniform cross-section having at one of its curved sides a permanent istortion of the metal in the nature of a circumferentially-directed compacting which is greatest at the region opposite the split and decreases in both directions.

4. A metal packing ring of uniform crosssection which exerts a circumferentiallyuniform radial spring pressure under working conditions by virtue of a circumferentially-varied distortion of the structureof the metal at one of its curved sides.

5. A metal packing ring consisting of a split'annulus of uniform cross-section having a permanent mechanical distortion on its inner side, said distortion being in the nature of a compacting of the metal varying circumferentially and causing the ring to exert a circumferentially-uniform outward radial spring pressure under working conditions.

6. A metal packing ring of uniform crosssection and uniformly distributed mass having at one of its curved sides a permanent circumferentially-directed and circumferentially-varied densification of the metal giving rise under working conditions to acircumferentially-uniform radial spring pressure.

7. A metal packing ring of uniform crosssection having at its inner side a permanent circumferentially-directed and circumferen- -tially-varied densification of the metal giving rise when the ring is circularly confined to a circumferentially-uniform outward radial spring pressure. J

S. A cast iron packing ring consisting of a split annulus of uniform cross-section having a permanent mechanical distortion on its inner side varying in both directions from maximum at the point opposite the split to minimum toward the split.

9. A metal packing ring having a permanent circumferentially-varied distortion of a structure of the metal at one of its curved sides and adapted by virtue thereofto exert under working conditions a radial spring pressure that is equal at all points circumferentially of the ring.

10. A metal packing ring having a permanent circumferentially-directed and circumferentially-varied densification of the metal at one of its curved sides and adapted by virtue thereof'to exert under working conditions a radial spring pressure that is equal at all points circumferentially of the ring.

11. A metal acking ring which exerts a circumferential y uniform radial spring pressure under Working conditions due to permanent densification of the metal at one of its curved sides, such densification being produced in transverse lines or strips.

12. A metal packing ring of uniform cross-section having densification areas of intensity varying from maximum at a central point toward minimum in both directions therefrom distributed along oneof its curved sides.

13. A metal packing ring consisting of a .splitannulus of uniform cross-section hav its curved surface regions mechanically and permanently distorted in the nature of a superficial circumferentiallydirected compacting of the metal varying in degree from maximum at the point opposite the split to minimum at the ends.

14. The combination with a piston of a metal piston ring therein consisting of a split annulus of uniform cross-section having the structure of the metal along its inner circumference densified in a circumferential direction and in varying degree and adapted to exert an outward radial pressure equal at all points against the confining cylinder wall.

15. The combination of a metal packing ring and a cylindrical surface with which saidring has relative sliding contact, said ring consisting of a split annulus of uniform cross-section having the structure of the metal at one of its curved sides densified in a circumferential direction and in varying degree and exerting a radial pressure against said cylindrical surface equal at all points circumferentially.

'In testimony whereof, I have signed 'my name to this specification, in the presence of two subscribing Witnesses.

ROBERT B. WASSON.

ing one of \Vitnesses:

WV. F. BIssINo, L. F. LI'l'lLE.

transverse-striplike

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