US2059168A - Packing - Google Patents

Description

Oct. 27, 1936. W DE WlTT 2,059,168

PACKING Filed Oct. 4, 1934 INVENTOR. Walter Morse De W131i.

ATTORNEY.

Patented Oct. 27, 1935 tttaltt PACKING Walter Morse De Witt, Somerville, N. J assignor to J chns-Manville Corporation,

New York,

N. Y., a corporation of New York Application October 4,

2 Claims.

This invention relates to a packing and to the method of making the same. i

In the case of semimetallic packings, to which the preferred embodiment of the present invention is directed, there have been made heretofore numerous structures having each a core and strips of metal wound therearound. In some such structures the wound strips of metal are subject to being shifted from side to side as the packing embodying such structure is subjected to superficial stress and repeated flexing during use. In other structures having a number of layers of metal applied, one over another, there has been a tendency for amalgamation or welding together of the strips in contact during use, as, for example, under pressure and at substantially elevated temperatures. Other packing materials have exterior casings of wire; the wire, not having a plane surface, is not adapted to maintain satisfactorily a thin continuous film of oil in contact with the packed surface.

The present invention comprises a packing having means for interlocking in approximately preestablished position fiat strips of metal applied around a core, means for avoiding continuous'contact between adjacent overlying metal strips, means for providing adequate lubrication of the surface of the packing, and/or means for maintaining such lubrication in contact with the surface that is packed. Other objects and advantages will appear from the detailed description that follows.

An embodiment of the invention that is preferred at this time is illustrated in the drawing in which Fig. 1 shows aview of a packing partly disassembled for clearness of illustration;

Fig. 2 shows a view of a fiat metal strip suitable for use in the present invention, the strip being somewhat distorted in order to show both faces thereof;

Fig. 3 shows a cross sectional view of the structure of Fig. 1, on an exaggerated scale;

Fig. 4: shows a perspective view of material of the type illustrated in Figs. 1 and 3, shaped into annular form; and

Fig. 5 illustrates a modified form of my'improved packing in which the strips of metal, a disposed around the core material, expose a substantial part of the said core on the exterior of the article.

In the various figures like reference characters denote like parts.

There is shown rod packing comprising a resillently yieldable core I consisting, suitably, of

1934, Serial No. 746,828

fibrous material of the type of fabricated asbestos fibres, such as braided or twisted roving, and a lubricant 2 disposed within the core. The lubricantmay be of the type of a composition of graphite and a lubricating oil, or other lubricating 5 grease or paste, and may be impregnated in large proportion into the said fibrous material.

Disposed around the yieldable core are a plurality of strips or ribbons of metal, of generally flat surface, interlocked with each other. The 10 metal of these strips is suitably soft and yielding and may consist, for example, of lead, aluminum, Babbitt metal, or the like. A desirable nature of interlocking is obtained by interbraiding the fiat strips of metal so that the several strips lie 5 fiatwise around the core, and, being intercrossed with each other, provide a sheath that minimizes the lateral displacement of an individual strip during use of the. packing. Furthermore, such method of interlocking gives a structure 20 provided with holes 3 adjacent to the positions of intercrossing and extending through the sheath. Since these holes are substantially regularly spaced in a given braid or sheath, they serve to permit the feeding of lubricant through a given 25 braid at closely and substantially regularly spaced positions.

For most purposes, I have found desirable the use of a plurality of series of such interbraided flat'strips of metal. Thus, 'I have used to ad- 30 vantage two to five such series of braids, in concentric relationship, with the'holes in one series in generally non-registering relationship with the holes in an adjacent series. Such adjacent series of interbraided strips of the metal are in- 35 dicated by 4, 5 and B.

In order to provide reservoirs for lubricant and to prevent welding together or amalgamation of the overlying strips in the structure described, the face and back of the several strips are provided 40 with irregularities of the type of the knurling i. This knurling .also prevents continuous contact between adjacent strips of metal and provides therebetween spaces adapted to permit diffusion of lubricant between the said strips To insure 45 further against undesired welding together or amalgamation of the adjacent strips, when in use the several strips are heavily coated on both face and back with a lubricant, such as one containing graphite dispersed in oil or grease.

The terms generally flat or generally plane, as used herein, are intended to describe strips of the kind illustrated in the various figures, even though the strips have minor irregularities, such as the knurling, or may be curved to constitute 55 an approximately tubular casing as shown in Fig. 1. These terms distinguish ribbons of metal from wire or from crumpled foil, for example.

In the modification shown in Fig. 5, the flat strips 8 of metal of the kind described are interbraided into a sheath provided with relatively large spaces betwen adjacent strips and exposing core material over a substantial part, say half, of the total area of the surface of the packing, at positions 9 intermediate the positions 8 occupied by the metal strips of generally plane but knurled surface. With a structure of this type, the exposed areas 9 of the lubricated core material provide a film of oil at the surface, at positions between the strips of metal disposed over the core material, and the areas 8 of the said strips serve to maintain this film of oil in excellent packing relationship between the surface of the strip and the surface being packed.

The article described may be made as follows:

Metal foil of selected kind and proper thickness is cut into strips of desired width and passed between two calender rolls or the like having knurled su aces, to produce on the face and back of the stri,-'the desired knurling. The strips or ribbons thusindented are passed through a viscous but appreciably fluent lubricating composition, such as a mixture of graphite in oil. Thus, the grooves formed by the knurling are filled and the areas between the grooves are coated with the lubricant. The excess lubricant is then removed, as by wiping in any convenient manner.

The lubricated core is prepared as by twisting asbestos roving and, if desired, interbraiding three or four strands of the twisted roving. The fibrous material is then impregnated thoroughly with appreciably fluent lubricant, as by being passed through a bath containing the desired lubricating composition. The lubricated metal strips are then braided around the lubricated core, as by means of a square packing braider of the kind used in braiding leather leashes for dogs. In one embodiment, the two series of the strips which are intercrossed with each other in the braiding operation cross at approximately a right angle.

A structure made as described and having a single sheath braided around the core may be used as packing or may be passed through a. bath of lubricant and used as a core around which a second, concentric jacket of lubricated knurled metal ribbons is braided, as before. This operation may be repeated, until the desired number of concentric braids has been applied.

The machinery used in fabricating such a product is not illustrated, as it is conventional and forms no part of the present invention.

The packing, made as described, has pronounced pliabillty or flexibility and is, therefore, easily applied and is quickly seated in a gland during use. At the same time, the interbraided strips are not easily displaced to a large extent from their preestablished positions relative to each other. There is thus avoided the condition, often prevailing in packings thathave been long in use, in which the nature of the exposed surface varies greatly at different positions, the core material being largely exposed at certain positions and the casing being slipped along the exterior to other positions. The packing has a very large carrying capacity for lubricants and the lubricant initially associated with the core has access to the exterior surface of the article, through theopenings 3 adjacent to the positions of intercrossing of the strips of metal in a given series and through the spaces between the plane portions of the several concentric layers of braided ribbons. These spaces are provided by the knurling, as illustrated at position in in Fig. 3, the spacing being somewhat exaggerated for clearness of illustration. The component parts of the packing may have various dimensions. In a typical article I .have used metal ribbons that are each approximately 0.12 inch wide and 0.01 inch thick, the closely spaced minor irregularities of surface, that is, the knurling providing grooves about 0.01 inch thick or less.

It will be understood that the details given are for the purpose of illustration, not restriction, and that variations therefrom may be made within the scope of the appended claims.

What I claim is.

1. A packing comprising a shaped article, a viscous appreciably fluent lubricating composition distributed therethroughout, and interfabricated fiat strips of soft metal forming the exterior surface of the article and having each a generally plane surface provided with a. multiplicity of closely spaced minor irregularities defining therebetween reservoirs for the said lubricating composition.

2. A packing comprising in combination a resiliently yieldable fibrous core, appreciably fluent lubricant disposed therein, a plurality of strips of generally plane surface of soft yieldable metal fabricated in interlocking relationship with each

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