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United States Patent Office
Patented Nov. 15, 1966
Nicholas D. Trbovich, 59 Fieldcrest Court,
West Seneca, N.Y.
Filed Sept. 20,1963, Ser. No. 310,223
5 Claims. (CI. 277—180)
This invention relates generally to the seal art, and more specifically to a new and useful seal of a type particularly adapted for use in place of rubber O-rings.
Metal seals possess certain advantages over rubber Orings, but also present a problem in providing the requisite strength and rigidity within the limitations imposed by existing cavity diameters and permissible flange loading. These limitations must be observed, if true interchangeability with rubber O-rings is desired.
Accordingly, the primary object of my invention is to provide a metallic seal of increased strength and rigidity, which seal is interchangeable with rubber O-rings without requiring any increase in cavity diameters and while maintaining a minimum in the compression force required for sealing.
Another object of my invention is to provide a metallic seal having the aforesaid characteristics, and having improved fatigue life and pressure capability.
Still another object of my invention is to provide the foregoing in a seal characterized by ease of manufacture.
In one aspect thereof, a seal constructed in accordance with my invention is characterized by the provision of a member of generally U-shaped transverse section having a base, side walls extending from the base, and laterally outwardly projecting flanges adjacent the outer ends of the side walls, the side walls tapering toward the flanges and the flanges projecting from the outer ends of the side walls a distance greater than the thickness of the side walls adjacent the flanges, the outer ends of the flanges being flat and providing surface engaging sealing areas.
In another aspect thereof, a seal constructed in accordance with my invention is characterized by the provision of a member of generally U-shaped transverse section having a base, side walls extending from the base, and laterally projecting flanges adjacent the outer ends of the side walls, the side walls tapering toward the flanges, and the flanges having flat surface engaging outer end portions which are substantially parallel when the member is unstressed.
In still another aspect thereof, a seal constructed in accordance with my invention is characterized by the provision of a member of generally U-shaped transverse section having a base, side walls extending from the base, and laterally projecting flanges adjacent the outer ends of the side walls, the inner surfaces of the side walls being substantially parallel when the member is unstressed, and the outer surfaces of the side walls converging toward the flanges.
The foregoing and other objects, advantages and characterizing features of my invention will become clearly apparent from the ensuing detailed description of an illustrative embodiment thereof, considered in conjunction with the accompanying drawing depicting the same, wherein like reference numerals denote like parts throughout and wherein:
FIG. 1 is a fragmentary, longitudinal sectional view of a joint incorporating a seal of my invention; and
FIG. 2 is a view, on an enlarged scale, showing the transverse sectional configuration of the seal.
Referring now in detail to the illustrative embodiment depicted in the accompanying drawing, there is shown a seal of my invention, generally designated 1, positioned in the cavity 2 of a tubular member 3, to which an end
flange 4 is secured, as by bolts 5. Seal 1 is shown in its installed, stressed condition in FIG. 1, while FIG. 2 shows the transverse sectional configuration thereof in its unstressed condition.
5 Seal 1 is of generally U-shaped transverse section, having a base 6 and side walls 7 extending from one side of the base. Side walls 7 terminate, at their outer ends, in laterally outwardly projecting flanges 8 having flat outer ends 9 comprising the surface engaging sealing
10 portions of the seal. That is, end surfaces 9 and particularly edges 9A thereof are in sealing engagement with the adjacent surfaces of members 3 and end flange 4. The sealing surfaces 9 and 9A are usually coated or plated with a ductile material 9B which will cold flow
15 when the seal is compressed. This further enhances the sealing ability of the seal.
The opposite ends of base 6 are flat, as shown at 10, from the outer side 11 of base 6 to a point short of the inner side 12 thereof. End surfaces 10 are parallel, and
20 act as mechanical stops preventing overcompression of seal 1, as clearly illustrated in FIG. 1.
In the unstressed condition of the seal, the inner surfaces 13 of side walls 7 are substantially parallel. The outer side surfaces 14 thereof are flat, like inner surfaces
25 13, but converge from the base end portions 10 to flanges 8. This provides side walls 7 of tapered form, the degree of taper being such that the thickness of side walls 7 adjacent flanges 8 at the outer ends of the side walls is less than half the thickness of the side walls adjacent
30 base 6.
This tapered side wall configuration tends to equalize stress distribution throughout the seal, and avoids stress concentrations to provide better fatigue life and pressure capability. Further, the material of the seal member
35 is concentrated at the base 6, producing a stronger seal without increasing cavity size such as would be required if an attempt were made to strengthen the seal by increasing its size throughout. This design also provides a seal of increased rigidity, without a corresponding in
*° crease in the compression force required to effect the seal.
The provision of initially substantially parallel inner wall surfaces 13 facilitates the manufacture of a tapered wall seal, with its advantages, by avoiding the problems 45 introduced by the critical nature of an internal taper. It also facilitates varying the thickness of base 6, and consequently the hoop strength of the seal, without affecting either the taper or the outer end wall form of the seal.
50 Flanges 8 project outwardly beyond the base end portions 10, in the unstressed condition of the seal, as clearly shown in FIG. 2. The flanges project beyond the side walls 7, at their outer ends, a distance substantially twice the thickness of the side walls 7 at the outer ends thereof.
55 Further, flanges 9 are of substantially square transverse section, in the portion thereof projecting beyond the outer ends of side walls 7, thereby providing a sealing surface 9 of substantial area, for increased sealing effect as contrasted with the situation which would prevail if flange
60 8 made substantially only point contact with member 3 and end flange 4. The initially substantially parallel ends 9 are important, because as the edges 9A are compressed the material 9B is caused to cold flow across ends 9 and into the irregularities of the sealing surfaces on members
65 3 and 4, as indicated in FIG. 1, to provide a greater area of sealing contact and enhanced sealing effect. If the ends 9 were initially tapered, the ductile material cold flowing away from edges 9A would not be retained in sealing contact with members 3 and 4, and its sealing
^° effect would tend to be lost, leaving substantially only knife edge contacts between the base metal of seal 1 and
members 3 and 4. It is contemplated that at least end portions 9, if not the entire seal, will have a coating 9B of malleable material such as silver, gold, nickel, copper or Teflon, for example, which will deform and cold flow under the pressures involved into surface irregularities in g members 3 and 4, to increase the sealing action.
The corners between the meeting surfaces are rounded, as clearly shown in FIG. 2, except at the sealing end portions 9 of flanges 8. Also, it will be noted that the concentration of material at base 6 is such that, not only are the walls 7 much thicker adjacent base 6 than they are adjacent flanges 8, but base 6 itself is much thicker than wall members 7 at any point therealong. This provides maximum hoop strength for a given diameter.
Accordingly, it is seen that my invention fully accom- 15 plishes its intended objects. While I have disclosed and described in detail only one embodiment of my invention, that has been done by way of illustration, it being my intention that the scope of my invention be defined by the appended claims. 20
Having fully disclosed and completely described my invention, and its mode of operation, what I claim as new is:
1. A seal comprising an annular unitary metallic member of generally U-shaped, radially facing transverse sec- 25 tion having a base and opposite side walls extending from one side thereof, said side walls terminating at their outer ends in laterally outwardly projecting flanges, the opposite ends of said base comprising stops against overcompression of said seal, the inner surfaces of said side 30 walls being flat and substantially parallel when said member is unstressed, and the outer surfaces of said walls converging toward said outer ends thereof from said base, the thickness of said side walls adjacent said outer ends thereof being no more than substantially one-half 35 the thickness thereof adjacent said base, said base being thicker than said side walls at any point therealong, said flanges projecting beyond said opposite ends of said base and terminating in flat surface engaging sealing end por
tions, said surface engaging end portions being substantially parallel when said member is unstressed and having
a coating of ductile material which will cold flow into irregularities of the surfaces being sealed.
2. A seal as set forth in claim 1, wherein said coating comprises a malleable metal.
3. A seal as set forth in claim 1, wherein said coating comprises a malleable non-metallic material.
4. A seal as set forth in claim 1, said opposite ends of said base being flat and substantially parallel from the other side of said base to a point substantially short of said one side thereof to comprise said stops against overcompression of said seal.
5. A seal as set forth in claim 1, said opposite ends of said base being flat and substantially parallel to comprise said stops against overcompression of said seal, the outer surfaces of said walls being flat and converging toward said outer ends thereof from said flat ends of said base to said flanges when said member is unstressed, the outwardly projecting portions of said flanges being of substantially rectangular transverse section, and the corners between said other side of said base and said opposite ends thereof and between said inner wall surfaces and said flanges being rounded.
References Cited by the Examiner
UNITED STATES PATENTS
2,547,185 -4/1951 Bolhar 277—206
3,083,023 3/1963 Crearey 277—206
FOREIGN PATENTS 614,140 5/1935 Germany. 926,789 5/1963 Great Britain. 321,378 10/1934 Italy.
OTHER REFERENCES Machine Design "The Seals Book," The Pentaton Publishing Co., Ian. 19, 1961 (Copy in Div. 360 (TI 246 M3)).
SAMUEL ROTHBERG, Primary Examiner.
EDWARD V. BENHAM, LAVERNE D. GEIGER,
I. S. MEDNICK, Assistant Examiner.