US2375869A - Segmental packing ring - Google Patents

Description

May 15, 1945. J. w. PRICE, JR

SEGMENTAL PACKING RING Filed NOV. 20 1943 e 0 T N E V m a 0 1 WITNESS f kTTaR/vEr Patented May 15, 1945 7 2,375,869 SEGMENTAL PACKING RING Joseph W. Price, In, Jenkintown, Pa., assignor to The United States Metallic Packing Company, Philadelphia, Pa., a corporation of Pennsylvania Application November 20, 1943, Serial No. 511,188 1 Claim. (01. 288-13) My invention relates to that class of metallic packing rings comprising a plurality of cooperative segments and is of particular advantage in, although not confined to, rings of the type disclosed in U. S. Patent 9l4,426, granted March 9, 1909, to C. W. G. King which since their invention have gone into extended use, being employed for packing, among other things, the piston rods of locomotives for which purpose they are especially well adapted. These rings comprise a plurality, usually a pair, of segmentseach of which is provided proximate one end with a convex outer surface and proximate its other with a concave inner one whichwhen the ring is assembled overlaps the convex surface on the adjacent segment, the segments as a whole thus forming the complete ring. In use the ring is applied about the rod and so mounted and arranged in a supporting structure that as wear takes place between the inner surface of the ring and the rod the interfitting concavo-convex surfaces of the segments are supposed to gradually and progressively move relatively to each other and thereby decrease the internal diameter of the ring to constantly maintain a steam tight joint with the rod. In practice, however, this result is not'always completely and adequately attained by reason of the fact that the mutually engaging surfaces of the segments frequently tend to gall and seize and when this occurs to any markedextent the. requisite free sliding movement between the segments is partially or sometimes wholly interrupted and the ring thus prevented from properly closing about the rod to compensate for wear, which results in leakage between the ring and the rod.

This difficulty with rings of the type to which my invention relates doubtless arises in some part at least from the fact that all the interfitting segments are made of the same relatively soft metal, usually a mixture of lead and copper, which affords an extremely satisfactory bearing surface with the steel piston rod but an unsatisfactory one with itself.

Various attempts have therefore been made to overcome the galling and seizing of the contacting surfaces of the ring segments but as far as I am aware none of them has been fully satisfactory. Thus, for example, one or both of the said surfaces have been sprayed or plated with various metals such as Monel metal but the coatings applied in this way do not adhere with sufficient tenacity and so peel off or form balls or granules between the segments which score their surfaces and inhibit relative free sliding movement between them.

A principal object of the invention therefore is to provide an improved segmental packing ring comprising simple and effective means for preventing galling or seizing of the ring segments and assuring proper freedom of movement between them as the ring as a whole is gradually constricted about the rod with which it is associated.

A further object is the provision of a ring which can be manufactured at substantially the same cost as the rings of ordinary construction and corresponding size and which can be employed in lieu thereof without necessitating any changes in the ring supporting mechanism of the machine of which the ring forms a component operative part.

Other objects, advantages and novel features of design, construction and arrangement comprehended by the invention are hereinafter more particularly pointed out or will be apparent to those skilled in the art from the following description of one embodiment thereof as comprised in a'ring of the general character disclosed in the saidKing Patent 914,426 and illustrated in the accompanying drawing.

v In the said drawing, Fig. 1 is a plan View of the assembled ring; Fig. 2 is a side elevation thereof partly broken away into radial section;

Fig. 3 is a fragmentary view showing the cooperating ends of two of the segments slightly separated; I n

Fig. 4 is a fragmentary perspective view likewise showing the ends of two segments slightly separated; I I

Fig. 5 is an end view of one of the shims hereinafter described as it would appear if removed from the segment end; and Y Fig. 6 is a side elevation of the shim as it is cut from the sheet.

The same parts are correspondingly designated in the different figures. I

As shown, the ring'comprises a pair of interfitting similar segments I, 2 although it may comprise a greater number, the segments being so constructed that when assembledin operative relation they form a complete ring as shown in Figs. 1 and 2, providing a central bore 3 surrounded by -a cylindrical portion 6 and a conical portion 5 in the customary manner.

Each segment is formed to provide at one end a convex face or surface 6 extending from the concave surface llikewise extending' from the periphery to the inner surface and adapted to overlie surface 6 when the ends of the two segments are in juxtaposed relation after the segments are assembled.

As so far described the ring is therefore of customary construction and, when assembled about a rod or shaft, the interfitting concavoconvex end surfaces of :the segments are designed to slide on each'oth'er as wear takes place between the bore of the ring and the rod so as to maintain the ring properly constricted at all times about the latter and inhibit; the :passage :of steam or other fluid along the rod pas the ring. But, as hitherto explained, the 'relative.freefiom of movement between the segments'reguisite for satisfactory accomplishment of this function is frequently unattained because of galling or seizing of the mutually engaging surfaces ofzthe segments.

In accordance with my invention I attach to that end .of each segment proximate itsconcave surface '1 an element In formed =of .sheet :metal which .for convenience .1 term a shim although its function is not :strictly that of the articles which are normallycharacterized as such. This shim is of :composition other than that of the segment and I prefer .to make it of sheet-copper since that metal gives most satisfactory results in. practice, but other metals can be utilized if desired. Sheet copper is considerably harder than the lead-copper mixture of which'sthe segmenis are usually formed iyet not-hardenoughxto injure the rod or shaft with which the :ring is associated if it contacts therewith, so if some metal other than copper be employed .=it should be of a character such that it will neither he injuriously affected-by steamer comparable fluids nortend to score therodto anappreciable extent.

The shim is cut from the sheet substantially to the shape shown in,-Fig. 6 and'comprises saifacing portion l0 which :generally conforms .in shape to -the "concave surface :on (the segment and .an anchoring portion 4-0" which zapproxim'ates :in width the peripheral :surface of the cylindrical part 4 of the flatter. o-pliimum results are obtained when the shimis mademelatrvely thin, for example ;0l-5,1as.the wear on its facing part is substantially tnegli'gi-ble and thus no advantage is attained by utilizing ma'terially thicker metal.

Suitable means areprovided'for anchoring 'the shim in proper position on the segment "and to this end I prefer to provide the 'peripheralsurface -.of the cylindrical part 4 with a-transverse saw cut or other suitable slot l2 directed more or less-toward the proximate end 'Qfthe ring to which the shim is to be appliedan'd thus -in a non-radial direction, this slot being adapted .to receive the extremity a o'fthe anchoring, portion I 0" of the shim which is forced'into thes'lo'tand the sides of the latterthen "swaged down with a few light hammer blows. The'bo'dy of the shim is then "bent around "the segment so as to .ibring the rest of "the anchoringportion l0" alongeits peripheral surface, thence .over the .endof the segment which is preferably slightlyroundedas at [3, and finally over .the.concave face 7 in-such manner that the shim vwill.snugly.hug the underlying portions of the segment. llfpreferred however, the shim may first be bentiappmximately to.fina.l form as shown in Fig. .5 and then slid edgewise .over .the end of -.the -segment with *the extremity a of theanchoringtportionrinzthesslot and the walls of :the :latter then'scnnstricted :as

just described so as to hold the shim firml in place.

In practice the shim is preferably initially cut slightly larger in all directions than the surfaces of the segment which it is ultimately designed to overlie and trimmed off along its edges after it is secured in place so it will not overhang any portion of the segment, this trimming of all but the inner edge b of the shim being most conveniently effected when the ring is assembled and outer surfaces turned to final size by the manufacturer. Normally, however, the interior of the ring is not then finished but is later bored out by the user to conform to the exact diameter of .the rod with 'which the ring is to be associated and thus the edge b of the shim is allowed to extend somewhat into the bore, as indicated in dotted :lines2in :Eig. :3, until it is finally fitted to therod .during which operation the projecting portion is of course removed.

It will nowabe apparent that when .the se ments are assembled that portion of the shim overlying the concave surface let each segment engages the :convex :surface 6 of the proximate segmentand as the shim is positively anchored to :thesegment :to which -it is attached .the-.sliding movement between the two segments as the r is constricted takes place between the shim and said convexsurface.

As .has been :definitely demonstrated in :actual practice, objectionable gelling and "seizing between the surfaces is thus :reduced to :a negligible degree or entirely obviated, the convex surface of each segment moving a'freely and :smoothly an the concave surface qof ithe (51111111011 the adjacent one .until the wing is worn so :thin as to he no longer serviceable. "In fact on locomotive ,DISISOD rods and undersimilar:operatingconditionsrings embodying .my invention have shown upwards -:of three :times -.the service life computed :inlocomotivemiles of operation ofprdinarynngs of similar type. Thus the invention notsonly materially reduces'the aexpenseentailed-in the purchase and installation 'of new rings :but lessens ithB :time :in which :the docomotive :is out :of service during :a given period hecause :of the necessity for :ring replacement.

.It may he :noted at :this .point :that ;the ring.

sivelydecreasestowardrtheir other ends, with the result that ultimately the radial-width of each segment at :thezintersection :of its surface 6 with its :peripheral surface is materially :less than at the inner :endof its concave surface 1 whereby as termination of the service life of the ring approaches-a considerable .part of the facing portion of .eachshim is entirel out of:contact with what remains of surface 6 :of the adjacent segment.

While I have herein 1 described and illustrated with considerable particularity one embodiment ofsmyinvention which has proved eminently satisfactoryin practice, I do not therebydesire =01- intend to specifically :restrict myself thereto or toits use with rings 0'f1any particular type, while various :changes (and modifications may 'be' made in the form, construction :and assembly of the various elements if desired -without departing from the spirit :and scope of the invention-as defined in the appended claim.

Having thus described myinvention, I =claim segment with a slot extending inwardl from the peripheral portion towards the concave surface of the same, and a sheet metal shim of substantially harder metal than that of the packing ring and consisting of a tapering facing portion overlying and conforming substantially to the configuration of said concave surface, and an oblong anchoring portion overlying the periphery of the segment at said cylindrical portion and extending into said slot to anchor the shim to the segment.

JOSEPH W. PRICE, JR.

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