US1357219A - Packing-ring - Google Patents

Description

M. B. BREWSTER;

PACKING RING.

APPLICATION FILED APR. 8, I920.

1,357,219. Patented Nov. 2,1920.

UNITED STATES MORRIS B. BREWSTER, OF CHICAGO, ILLINOIS.

PACKING-RING.

Specification of Letters Patent.

Patented Nov. 2,1920.

Application filed April 8, 1920. Serial No. 372,120.

have invented a certain new and useful Improvement in Packing-Rings, and declare the following to be full, clear, and exact description of the same, such as will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

The use of superheated steam in steam locomotives, and consequently the high temperature of the steam, has introduced problems in the packing of the piston rods, the materials employed for making packing rings adapted for low pressure work being entirely inadequate. Thus, for example, compositions of lead and antimony, which would otherwise be satisfactory, will melt at too low a temperature. Recourse has therefore been had to compositions made of lead and copper. the best results having been obtained with compositions containing fifty per cent. of lead and fifty per cent. of copper. However, there are difiiculties in the way of manufacturing these lead-copper rings, the castings being porous and, even though they may appear to be sound superficially, when they are machined to fit them to the piston rods large pores or blow holes will often be exposed and make it necessary to throw the rings away. Even if the rings are otherwise sound, the fact that they are extremely brittle at high temperatures detracts from their usefulness. Another disadvantage of these rings is that their value as scrap is small as compared with the initial cost of the material out of which they are made.

The object of the present invention is to produce a simple and novel form of packing ring which will serve satisfactorily when subjected to comparatively high tem eratures and which will be free from the o jections above noted in connection with rings made of a lead-copper composition.

In carrying out my invention I make the packing rings out of two kinds of metal, one of which will possess the desirable antifriction qualities of a packing ring while the other will supply the necessary mechanical strength which the first lacks. To this end I make a rudimentary packing ring preferably of lead and sheath it in a layer of copper except on the surface WhlCll is to contact with the piston rod; the lead having a melting point sufiiciently high to withstand the temperatures to which it is subjected, and possesslng also the desired anti-friction qualities. The copper sheathing, on the other hand, confines and protects the lead so as to make the ring as a'whole retain its shape, at least to a degree suflicient to enable it to carry out its functions as a packing ring. In other words, the'copper stiffens the ring but leaves it sufliciently ductile as a whole to permit it to yield under the pressure to which'it is subjected by the surrounding molding means and mold itself to the rod as wear takes place, thus maintaining a tight joint.

The various features of novelty whereby my invention is characterized will hereinafter be pointed out with particularity in the claimspbut, for a full understanding of my invention and of its objects and advantages. reference may be had to the following detailed description taken in connection with the accompanying drawing, wherein:

Figure 1 is an axial section taken through a well known type of piston packing, only those elements adjacent to the packing ring being shown Fig. 2 is a plan view of the packingring itself;

Fig. 3, is a section on line 3-3 of Fig. 2; and

Fig. 4 is a sect-ion similar to Fig. 3 illustrating one method of manufacturing the ring.

Referring to the drawing, 1 represents a piston rod, 2 the packing ring as a whole, 3 the gland of the stufling box, 4; the sliding plate between the packing ring and the stuffing box, 5 and 6 the retainer and shell respectively; these parts, except for the novel construction of the packing ring, being old and well known and being shown simply to illustrate one of the many forms of packing in which my improved ring may be employed. The contour of the ring, except that-at one end or side it shall have an external surface in the form of a frustum of a cone whose axis is coincident with the axis of the ring and the number and shape of the parts into which it is divided form no part of the present invention since these characteristics will depend upon the type of packing in which the ring is employed.

In accordance with my invention, as illustrated in Fig. 3, I form the packing ring of a rudimentary ring, 7, which may be made of any suitable anti-friction metal such as will ordinarily not possess the necessary mechanical strength to retain its shape in service; lead being an example of such material. The member 7 is sheathed with a suitable metalfsuch as copper, preferably in the form of a shell, 8, which completely surrounds the ring while leaving its inner bearing face, 9, exposed. The ring may be formed by first fashioning the sheathing or shell and then, after tinnin the inside thereof, pouring the lead fillmg into the same. On the other hand, the rudimentary ring may be cast and the sheathing or shell be formed about the same afterward.

- In Fig. 4 I have illustrated a rudimentary ring, 10, which, after having been cast, is placed within a short cylin e r of copper, 11, having at one end an inwardly-turned flange, 12. The other end of the cylindrical member 11 is then pressed inwardly from the position shown in dotted lines to that shown in full lines at 14, thus producing a i ompleted ring similar to the ring shown in The shell or sheathing is made heavy enough to supply the ring, with sufficient mechanical strength to hold in shape the softer anti-friction element which would not of itself be capable of withstanding the pres sures to which the ring is subjected. It Will be seen that a composite ringof this kind can be made easily and cheaply, that such a ring will be free from the imperfections apt to be found in any copper-lead ring, that it will be durable, and that when its useful life is over its value as scrap will be practically the intrinsic value of the metals of which it is composed.

While I have illustrated and described with particularity only a single preferred form of my invention, Ido not desire to be 1. A divided packing ring for a piston rod of the type which by reason of its ductility molds itself to the rod under the influence of external pressure as wear takes :place and thus compensates for wear, comprising a soft metal core and a stiffer sheathing of ductile metal extending over the same and leaving the inner wearing surface of the core exposed.

2. A divided packing ring for a piston rod of the type which by reason of its ductility molds itself to the rod under the influence of external pressure as wear takes place and thus compensates for wear, comprising a lead core and a sheathing of thin copper extending over the core and leaving the inner wearing surface of the core exposed.

3. A divided packing ring comprising a lead core and a sheathing of thin copper extending over the core and leaving the inner wearing face of the core exposed, one end or side of said ring being in the form of a frustum of a cone having its axis coincident with the axis of the ring.

4. A divided packing ring comprising a core of soft metal having a cylindrical wearing surface at its inner diameter and one side or end in the form of a frustum of a cone whose axis is coincident with the axis of the ring, and a thin copper sheathing extendin arouhd the exterior of the core and its conical portion and leaving said wearing surface exposed.

In testimony whereof I sign this specification.

MORRIS B. BREWSTER.

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