3,013,830
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`Y
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`G. R. MILLIGAN
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`PACKING
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`Filed June 27, 1958
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`Tsii
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`Dec. 19, 1961
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`NI S Y
`SI IN
`S. W.
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`32A
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`INVENTOR
`(7áOe6A /, /////6AW
`BY 16-74-444
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`GDI Ex. 1018
`Page 1 of 4
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`United States Patent Office
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`3,013,830
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`'E
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`0.
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`5
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`20
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`2
`are usually caused to face the direction from which the
`pressure of the sealed lubricant or fluid emanates.
`Hence, it may be assumed that the pressure or the sealed
`fluid seeking to pass between the shaft 20 and the casing
`18 is upwardly directed as viewed in the drawing. Such
`pressure, finding its way into the stuffing box, acts upon
`the bottom or inner surfaces of lips 26 and 30 to urge
`those lips, respectively, outwardly into firm, well-main
`tained sealing engagement with cylindrical surface 28 and
`inwardly into firm, well-maintained sealing engagement
`with the rod or shaft 26.
`The packing assembly and the parts associated there
`with are not represented to be novel as thus far described.
`There is novelty, however, in certain features of the rings
`i0 and of their manufacture, and of their cooperation
`with each other and with associated machine parts.
`Referring particularly to FIG. 3, the packing ring 10 is
`molded to its illustrated or more or less equivalent shape.
`It has a core 32 of relatively soft rubber or rubber-like
`material (all such materials being hereinafter referred to
`for convenience merely as "rubber') preferably com
`pletely encased within an envelope 34 of fibrous fabric,
`the outer Surface areas of which are covered or filled as at
`36 with compressed polytetrafluoroethylene. The method
`..of making such rings and the novel results of using such
`rings will now be described.
`The rings 10 or equivalent rings may be manufactured
`by frictioning one side of a suitably shaped sheet of
`fabric, which is to become the envelope 34, and wrapping
`that sheet, with its frictioned side facing inwardly, about
`a circular blank of uncured rubber, which is to become
`the core 32. Then, finely divided or powdered polytetra
`fluoroethylene is applied to the entire outer surface of the
`fabric, whereafter the thus-enveloped blank is molded in
`suitable dies to its ring shape and to the cross-sectional
`shape shown in FIG. 3.
`The fabric may be cotton or other fibrous material and,
`if desired, may include asbestos to increase its capacity to
`endure heat. The fabric should be of fine enough weave
`to enable it to substantially oppose outward passage of
`core rubber therethrough during the molding operation
`or in use.
`The mentioned frictioning of the inner surface of the
`fabric may be accomplished merely by brushing or wiping,
`upon said surface, and somewhat into the interstices at
`the inner side of the fabric, a suitable rubber-like sub
`stance which may function as an adhesive in effectively
`uniting the fabric envelope 34 to the rubber core 32 dur
`ing the molding operation. In some circumstances, as
`where the selected fabric is of a character which quite
`readily adheres to rubber, the application of a rubber-like
`adhesive substance to the inner surface of the fabric may
`be omitted.
`The fabric should preferably be so shaped and so ap
`plied to the rubber-core blank that marginal portions of
`the fabric overlap at points or areas which are not to be
`in sealing engagement with an adjacent machine part.
`Thus, such overlap is preferably at the inner side of one
`of the sealing lips 26 or 30, being shown in the drawing
`as so located at 38 on lip 30.
`The powdered polytetrafluoroethylene may convenient
`ly be applied to the fabric envelope, before the molding
`operation, in the form of a suspensoid wherein the pow
`dered polytetrafluoroethylene is admixed with water or
`other suitable liquid. The suspensoid may be brushed
`onto the outer surface of the fabric envelope 34 or a
`fabric-enveloped blank may be dipped into and agitated
`in the suspensoid. As thus applied, the polytetrafluoro
`ethylene finds its way into the interstices at the outer
`side of the fabric and completely covers the envelope 34.
`The suspensoid-coated blank is molded only after the
`suspensoid has dried sufficiently to avoid material steam
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`1.
`3,013,830
`PACKNG
`George R. Milligan, Palmyra, N.Y., assignor to Garlock
`Inc., a corporation of New York
`Filed June 27, 1958, Ser. No. 745,069
`7 Claims. (Ci. 288-17)
`This invention relates to an improved packing such as
`is used, for example, between relatively movable machine
`parts, to oppose leakage of lubricant or other fluid (often
`under pressure) between those parts.
`An important object of the invention is the provision of
`Such a packing which has extremely low frictional engage
`ment with a relatively movable machine part and, hence,
`minimizes drag between related, relatively movable
`machine parts.
`Another important object is the provision of such a
`packing which, when used with another packing conform
`ing to this invention, is capable of some sliding action of
`Some of its portions in relation to said other packing or
`portions thereof.
`Another important object is the provision of a more
`durable packing.
`Another important object is the provision of an assem
`bly of packings wherein several related packings in the
`assembly are so constructed and arranged that slippage
`therebetween enhances the functioning of the assembly
`as a whole.
`The foregoing and other more or less obvious objects
`and advantages are achieved by this invention of which
`certain embodiments are shown and described herein for
`illustrative purposes without, however, limiting the inven
`tion to those particular embodiments.
`In the accompanying drawing:
`FIGURE 1 is an axial, sectional view of a packing
`assembly according to a preferred embodiment of this
`invention, in association with relatively movable machine
`parts which are only fragmentarily shown.
`FIG. 2 is a fragmentary cross-sectionalized, perspective
`view, of packing, according to this invention, of the
`character illustrated in FIG. 1.
`FIG. 3 is an enlarged, cross-sectional view of the pack
`ing included in FIG. 1 and shown in FIG. 2.
`FIGS. 4 and 5 are perspective views showing, respec
`tively, the inside and the outside of another form of pack
`ing according to this invention; this form being designed
`for use as a piston cup or packing.
`FIG. 6 is an enlarged, cross-sectional view of the piston
`cup illustrated in FIGS. 4 and 5, substantially on the line
`6-6 of FIG. 4.
`Referring to FIGS. 1-3, the packing assembly is shown
`as comprising a plurality of similar, somewhat pliant or
`deformable packing rings 10, of approximate U-shape in
`cross Section. These rings internest to some extent with
`each cther, and the top and bottom rings of the assembly
`internest, respectively, with top and bottom rigid adapter
`rings 12 and 4; all the mentioned rings being confined in
`a stuffing box 16 formed in an outer machine element or
`casing 8 within which a rod or shaft 20 reciprocates or
`rotates. The mentioned ring assembly is retained within
`the stuffing box by a gland 22 which may be urged down
`wardly or inwardly of the stuffing box by screws 24 to
`place the packing-ring assembly under suitable axial
`compression.
`Each of the packing rings 10 has an outer sealing lip
`26 in substantially static or only slightly shiftable sealing
`engagement with inner cylindrical surface 28 of the stuff
`ing box 16, and an inner sealing lip 30 in slidable sealing
`engagement with the cylindrical, outer surface of the rod
`or shaft 20.
`When packings of the general character just described
`are used, the concave or inner end faces of the rings 10
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`GDI Ex. 1018
`Page 2 of 4
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`0.
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`3,013,830
`4.
`3
`polytetrafluoroethylene or very substantial portions there
`ing in the mold. With some types of fabric envelopes it
`of for the purposes of this invention.
`may be feasible, within this invention, to apply the pow
`The embodiment illustrated in FIGS. 4-6 yields some
`dered polytetrafluoroethylene in its dry state to the outer
`advantages although not all of the advantages herein
`surface of the envelope 34 before the molding operation,
`before indicated. In said embodiment, a fabric envelope
`although the application of the polytetrafluoroethylene in
`34a constitutes an outer covering for a flat piston-cup
`suspensoid is considered more thoroughly effective.
`body 32a of rubber and an integral, more or less cylin
`After the thus-treated blank has been properly Sub
`drical, rubber, sealing flange 32b. The envelope 34a,
`jected to heat and pressure in the molding operation, it
`however, does not extend about the inside of the rubber
`is released from the mold. It should here be noted that
`parts 32a, 32b. It is associated with said rubber parts,
`the low coefficient of friction of the outer surface of
`however, by having the rubber of parts 32a, 32b, or inter
`the resultant packing, arising from its coating of poly
`vening rubber-like adhesive material, filling the interstices
`tetrafluoroethylene, enables the substantially finished pack
`of the inner face of the envelope 34a. Similarly to the
`ing to be released readily from the mold without the
`first-described embodiment, the outer surface of the en
`necessity of employing any special mold-release agent.
`velope 34a is covered with and the interstices of the latter
`Having in mind that the finished packing rings 10 are
`surface are filled with polytetrafluoroethylene, applied to
`completely coated with polytetrafluoroethylene which has
`or introduced thereinto as hereinbefore suggested with
`a low coefficient of friction, it may be understood that
`respect to said first embodiment.
`each such ring would exert little or no drag upon the
`In the second embodiment, the presence of the poly
`moving rod or shaft 20; and that an entire assembly of
`tetrafluoroethylene minimizes friction at the outer surface
`Such packing rings would impose only a greatly reduced
`of the sealing flange, thereby conserving power and min
`drag, thereby utilizing most efficiently the power pro
`imizing wear of said flange and of the cylinder wall in
`vided for moving said rod or shaft. The reduced fric
`sliding contact with said flange.
`tion also minimizes or obviates scoring of the rod or
`Although, in the disclosed embodiments, the core 32
`shaft by the packing.
`(FIG. 3) and the body and flange 32a and 32b (FIG. 6)
`In prior assemblies of J-shaped packing rings in stuffing
`are described as being of rubber, those familiar with the
`boxes, the surfaces of the packing rings were such that
`art will realize that the just-mentioned parts may include
`upon continued application of pressure axially upon the
`reinforcing fabric in the rubber, in addition to the fabric
`assembly, the several packing rings would substantially
`envelope of this invention.
`seize each adjacent ring so that the assembly would be
`It will be understood that the present inventive concept
`come more of a unitary packing than a desired assembly
`30
`may be utilized in various other ways without, however,
`of packing rings. Where such assemblies and their com
`departing from the invention as set forth in the following
`ponent packing rings accord to this invention, each pack
`ing ring is capable of some slippage relatively to each
`claims.
`adjacent ring, thereby permitting each packing ring to
`| claim:
`1. A packing comprising a flexible body including rub
`shift slightly in a radial direction to compensate for wear
`ber therein, fibrous fabric adherently disposed upon a
`which might occur at one point in the one ring and not
`surface of said body, and finely divided polytetrafluoro
`at a corresponding point in an adjacent ring.
`ethylene on the outer face of said fabric and substantially
`This permissible slippage between rings also enables the
`occupying the fabric's interstices at said outer face.
`Sealing lips 26 and 30 to flex with relative freedom of
`2. A packing according to claim 1, further including
`inhibition which, in prior packings, arises from the axially
`adhesive material between said body and said fabric.
`compressed condition of the packing assembly. In prior
`3. A packing comprising a flexible body including rub
`packings wherein slippage between rings is not present,
`ber therein and at an outer area thereof, fibrous fabric
`flexing of a sealing lip was substantially localized toward
`overlying said outer area of said body, the interstices of
`its edge while in packings according to this invention
`the side of said fabric which faces said body being sub
`wherein such slippage is present, such flexing of either
`stantially occupied by portions of said rubber, thereby
`the outer or the inner sealing lip may occur throughout
`securing said fabric to said body, and compacted, finely
`the entire area between the lip's edge and the center of
`divided particles of polytetrafluoroethylene on the outer
`the packing ring. As the efficiency of U-packing as
`face of said fabric and substantially filling interstices of
`semblies arises largely from the flexibility of the sealing
`Said fabric at said outer face.
`lips of the packing rings, it will readily be realized that
`50
`4. An annular packing comprising an annular, flexible
`the enhanced flexibility of the sealing lips, in packing ac
`body of rubber including an integral, annular sealing
`cording to this invention, leads to substantially improved
`flange, fibrous fabric adherently overlying upon said body
`operating conditions.
`and flange with rubber of said body and flange substan
`There is believed to be a significant advantageous result
`tially occupying interstices of the adjacent face of said
`arising from the fact that interstices of the inner face of
`fabric, and finely divided polytetrafluoroethylene com
`the fabric of the envelope 34 are filled with rubber while
`pacted and held within interstices of the outer face of
`interstices of the outer face of that fabric are filled with
`said fabric and extending to the surface of said outer
`polytetrafluoroethylene. The advantageous result is that
`face to constitute the latter as a sealing surface.
`the polytetrafluoroethylene is well retained in the fabric
`5. A packing of U-shape in cross-section, comprising a
`although it would be expected that powdered polytetra
`rubber core having opposite sealing flanges corresponding
`fluoroethylene, because of its nature, would not be well
`generally to opposite portions of a U and a connecting
`retained in the fabric but would fall away, and thereby
`portion interconnecting said flanges, fibrous fabric ad
`fail to serve any purpose. There appears to be good
`herently and intimately overlying the outer faces of said
`reason to believe that the presence of rubber, filling all
`flanges and connecting portion with rubber of the latter
`the inner interstices, while permitting adequate flexing of
`and of said flanges extending substantially into interstices
`the Sealing ring, nevertheless, limits such flexing to rather
`of the inner face of said fabric, and powdered polytetra
`Substantial radii. Thus, powdered polytetrafluoroethylene,
`fluoroethylene Substantially occupying interstices of the
`which might be caused to escape from the packing ring
`outer face of Said fabric and substantially covering said
`if the latter or parts thereof were sharply bent, is retained
`Outer face.
`6. A packing according to claim 5, said packing being
`by the packing ring, according to this invention, by reason
`an annulus and said fabric also intimately overlying the
`of the fact that rubber, in said inner interstices, holds the
`inner faces of said flanges and connecting portion with
`ring against sharp bends. In that situation, the outer in
`Core rubber at Said inner faces extending substantially into
`terstices remain substantially unaffected by flexing of the
`interstices of adjacent inner surfaces of said fabric, and
`packing ring or parts thereof and effectively retain the
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`GDI Ex. 1018
`Page 3 of 4
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`

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`3,013,880
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`5
`6
`the outer interstices of the fabric which overlies said inner
`Greenoe -------------- Nov. 13, 1917
`faces of said flanges being substantially filled with pow
`Bruce ------------------ Jan, 22, 1929
`dered polytetrafluoroethylene.
`Hubbard---------------- Aug. 7, 1934
`7. A piston cup comprising a flat, annular body of
`Payne ----------------- Sept. 19, 1939
`rubber, an approximately cylindrical, rubber sealing
`Buffington -------------- May 21, 1946
`flange integral with and adjoining the outer periphery of
`Poltorak --------------- Jan. 18, 1949
`said body, fibrous fabric adherently covering the outer
`Spalding ---------------- Apr. 1, 1952
`faces of said body and flange, and finely divided poly
`Main ------------------ Aug. 23, 1955
`tetrafluoroethylene substantially occupying interstices of
`Kilbourne -------------- Dec. 18, 1956
`the outer surface of said fabric and substantially covering 10
`White ------------------ Sept. 3, 1957
`said outer surface.
`White ------------------ Oct. 6, 1959
`References (Cited in the file of this patent
`OTHER REFERENCES
`UNITED STATES PATENTS
`Product Engineering, September 1952, pages 149-153.
`Symonds -------------- June 11, 1878 15 (Copy in Classification Division V.)
`
`1,246,089
`1,700,091
`1969,008
`2,173,744
`2,400,533
`2,459,721
`2,591,383
`2,716,034
`2,774,621
`2,804,886
`2,907,612
`
`5
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`204,860
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`GDI Ex. 1018
`Page 4 of 4
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