In order to reduce the chance of overtightening of the fitting by the user. it has been suggested that a restraint be provided to limit the amount of compression that can be imposed on the seal gasket. For example, U.S. Pat. No. 5,482,332 provides axial projections adapted to engage one another, and thereby limit the potential for overtightening.

It is desired that the gasket be radially locked in place relative to the end faces while the end faces are advanced axially toward one another into sealing engagement with the gasket. In order to achieve this, the end face of the gland may be treated to ensure the end face properly engages the gasket. It is further desired that the sealed relationship between the gasket and the respective glands be maintained when a torque is applied to the fitting after make-up. For example, if torque is applied to a tube end while the remainder of the coupling assembly is held stationary, the torque may cause relative rotation between the gasket and a gland. It may further be desired to prevent relative rotation between the male nut and the gland within the male nut, as this arrangement helps to reduce transmitted torque.

Coupling assemblies of this type may be utilized in ultra-clean environments. which requires the reduction or elimination of minute particles that might be acceptable in less demanding environments. Thus, it is desired to decrease the prospect of particle generation.

Finally, tube couplings may often use a gasket retainer to retain the gasket in the proper radial orientation. In some designs, the gasket retainer may interfere with the proper make up of the coupling components. It is therefore desirable to use a coupling component or components that are adapted to receive the gasket retainer, yet can still properly engage the gasket.

The present invention is directed to a coupling assembly that addresses these issues by providing a coupling assembly that has positive stop feedback, resists torque, reduces relative motion between mating components, and increases the resistance of the coupling assembly to loosening after it is made up. In alternate embodiments. the coupling assembly is shaped to ensure proper engagement between the male nut and the male gland, is shaped to receive a gasket retainer, and has its end face treated so as to engage the gasket.

Summarv of the Invention According to the present invention. a preferred form of coupling assembly includes end faces of glands/coupling members disposed for sealing against opposite faces of an annular gasket. The end faces include a bead extending outwardly from the bore of the gland/coupling member, an annular recessed or substantially planar region disposed radially outward thereof: and a rim located radially outward of the annular planar region.

In one embodiment. the invention is a first coupling component comprising a body having a through bore and an end face and an annular, raised seal surface on the end face.

The coupling further includes a rim radially outward of the seal surface for engaging a gasket when the first coupling component is advanced toward and engaged with a second coupling component.

In another embodiment, the invention is a tube coupling assembly comprising a first coupling component having a through bore and an end face, and a second coupling component having a through bore and an end face, wherein the end face of the second coupling component is oriented so as to face the end face of the first coupling component.

The tube coupling assembly further includes a gasket located between the first and second coupling components. a threaded female nut shaped to receive the first coupling component therein, and a threaded male nut shaped to receive the second coupling component therein.

The male nut is shaped to threadingly engage the female nut. and has a shoulder shaped to frictionally engage the second coupling component to prevent relative rotation therebetween.

In yet another embodiment. the invention is a generally ED Iar coupling component comprising an end face having an outer diameter and an inner diameter. the inner diameter defining a through bore extending through the coupling component. The inner diameter is axially recessed from the outer diameter, and the end face further includes a contoured surface adjacent the inner diameter.

In a further embodiment, the invention is a first annular coupling component comprising an end face, a through bore and a retainer-receiving annular recess formed in the coupling component. The recess is shaped so as to receive a retainer therein when the first coupling component is advanced toward and engaged with a second coupling component having a gasket retainer mounted thereon.

Still other advantages and benefits of the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed description.

claims. and drawings. all of which form a part of the specification.

Rrief Description of the Drawings The invention may take physical forum in certain parts and arrangements ot parts.

Preferred embodiments of the invention will be described in detail in the specification and illustrated in the accompanying drawings.

Fig. 1 is an exploded cross-sectional side view of one embodiment of the coupling assembly of the present invention; Fig. 2A is a cross-sectional side view of the coupling assembly of Fig. 1. shown in the made-up condition; Fig. 2B is an enlarged detail view of the encircled area of Fig. 2A; Fig. 3 is an enlarged detail view of the encircled area of Fig. 1; Fig. 4 is an end view of the seal face of one of the coupling members of Fig. 1; Fig. 5 is a graphic representation showing torque vs. rotation of the coupling assembly for various coupling assemblies; Fig. 6 is a cross-sectional side view showing one embodiment of the coupling component of the present invention in use in a coupling assembly with a conventional coupling member; Fig. 7A is a cross-sectional view of one embodiment of the sealing face of the present invention shown on a block body;

Fig. 7B is an end view of the block body of Fig. 7A;.

Fig. 8 is a side cross sectional view of an alternate embodiment of the coupling component of the present invention: Fig. 9 is an end view of the coupling component of Fig. 8; Fig. 10 is a detail cross-sectional view along line 10-10 of Fig. 9; Fig. 11 is an end view of an alternate embodiment of the coupling component of the present invention; Fig. 12 is a cross sectional side view taken along line 12-12 in Fig. 1 1: Fig. 13 is a cross sectional side view of two of the coupling components of Fig. l 11.

shown made up with a gasket; Fig. 14 is an end view of another alternate embodiment of the coupling component of the present invention: Fig. 1 5 is an end view of yet another alternate embodiment of the coupling component of the present invention: Fig. 1 6 is an end view of a further alternate embodiment of the coupling component of the present invention: Fig. 17 is a cross sectional side view of a coupling assembly illustrating another alternate embodiment of the coupling component of the present invention; Fig. 1 8 is a perspective view of the coupling component of Fig. 8. with a portion of the component cut-away; and Fig. 19 is a detail. cross-sectional view of another alternate embodiment of the coupling component of the present invention.

Detailed Description Reference is now made to the drawings which illustrate the preferred embodiment of the invention only and are not intended as a limitation. Turning first to Fig. 1. a preferred embodiment of a coupling assembly A is shown therein. It includes a first coupling member or gland 10 and a second coupling member or gland 12. As briefly mentioned above. the coupling member may be a gland (as illustrated in Fig. 1) or may also be a surface of a fluid

component such as a valve, regulator, or the like that is to be sealingly connected to another coupling member. Thus, the following description applies to various types of coupling members and should not be construed as being limited to the embodiments shown unless specifically noted. Furthermore, like reference numerals will refer to like parts. unless otherwise noted.

Each gland 10, 12 is of generally hollow cylindrical configuration, and has a body 11.

A first end 14 of each gland 10, 12 is adapted for connection with a fluid system (not shown) such as a tube or pipe. A second end 16 of each gland 10. 12 has an enlarged diameter outer dimension that defines a rear shoulder 18. The rear shoulder 18 faces the first end 14 in one direction. and faces the seal face or end face 20 in the opposite direction.

Each gland 10, 12 has a through bore or passage 22 that extends from the first end 14 to the second end 16. and the passage 22 provides fluid communication through the coupling assembly A. A nut assembly 30. defined in the illustrated embodiment by a first or male nut member 32 and a second or female nut member 34, is received about the glands 10, 12. The end face 20 of each gland member 10. 12 is disposed in opposed facing relation so that the through passages 22 of the glands are in substantially aligned relation. As is well known in the art, the male nut member 32 includes external threads 36 that cooperate with internal threads 38 of the female member. The fitting is typically made up by causing the threaded advancement of the female member 34 relative to the male nut member 32, thereby urging the first and second glands toward one another. Tool or wrench flats 40 are typically provided on the nut members to facilitate make-up of the fitting. In this particular arrangement, an end 42 in the male nut member engages the radial shoulder 1 8 of the first gland. Likewise. a shoulder 44 of the female nut member engages the rear shoulder 1 8 of the second gland. Thus, as the nut assembly 30 is tightened. the glands are axially advanced toward one another.

Interposed between the end faces of the first and second glands 10, 12 is an annular gasket 50. The gasket 50 has an inner opening 52 that substantially matches the diameter of the through passages 22 in the glands. The outer perimeter 54 of the gasket is dimensioned to be approximately the same diameter as the outer edge of the end faces 20. The gasket is generally flat. and is preferabl! metal. Further preferably. the gasket is substantially cylindrical in shape: that is. the gasket preferably has flat sides and does not have anv notches, grooves, or cut-outs formed therein. However. in alternate embodiments the gasket

may have an annular cut-out. and the coupling of the present invention may be adapted to receive gaskets having such an annular cut-out, groove, or the like.

The end faces 20 of the respective first and second glands 10, 12 are adapted to sealingly engage opposed faces of the gasket 50. In a preferred embodiment, each end face 20 includes a circumferentially continuous bead or sealing surface 60 that is preferably defined by a smooth arcuate or curved surface (Figs. 2B and 3). Only one of the glands in a coupling assembly may have the shape described herein, or alternately both glands may have the described shape. In the illustrated embodiment. the bead or seal surface 60 of one of the gland members is disposed at a radially inner area of the end face 20 and protrudes axially outward from the seal face 20 a predetermined dimension D1 (Fig. 3). The dimension D1 as shown is measured from the planar area 64. The preferred bead configuration has a generally arcuate shape defined by a generally constant radius. Of course, other bead profiles may be used without departing from the scope and intent of the present invention. Preferably the center of curvature of the bead in the illustrated embodiment is disposed radially outward from the wall of the through passage 22 a dimension closely approximating the radius of the curve, although the bead is intended to extend axially outward from the end face 20 of the gland. The inner radial edge portion of the bead 60 is preferably smoothly transitioned into the through passage 22. For example, a chamfered surface 62 may interconnect the seal bead with the wall defining the through passage 22 of the gland.

Located radially outward from the bead 60 is a recessed region, or substantially annular planar region 64 that extends over a substantial portion of the radial dimension of the gland seal face 20. The planar region 64 is recessed relative to the bead 60 on the order of thousandths of an inch, for example. As will be described in greater detail below. the planar region 64 provides a positive feedback to the user upon make-up of the coupling assembly A.

When the fitting is sufficiently made up, the gasket 50 is deformed into the planar region, and the planar region 64 thereby provides an increase in makeup torque. This torque increase acts as a positive feedback to the user making up the coupling assembly.

Disposed at the radial outermost portion of the seal face is a rim 70. While the bead and planar region are preferably circumferentially continuous. the rim may include discontinuities. For example. the rim 70 may include first and second recesses 72. 74 (Fig. 4) which extend axially inwardly only a few thousandths of an inch (for example) into the rim.

preferably in the range of about 7 to 30 thousandths of an inch. The recesses 79.74 may be disposed in diametrically opposed relation. The recesses may extend over only a relatively

minor portion of the circumference of the end face 20. Moreover, although different numbers of recesses can be provided. one preferred arrangement includes discreet spaced recesses.

The rim 70 may be axially flush the furthest axial protrusion of the bead 60. In this case, the rim 70 extends forwardly from the end face 20 the dimension D1. Alternately. the rim may be a raised rim 70 which extends axially beyond the outer surface of the bead 60. In the embodiment illustrated in Fig. 3. the raised rim 70 extends forwardly from the planar region 64 by a dimension D2 which is greater than D1. This dimensioning of the raised rim 70 assures that during make up the rim 70 is the first portion of the seal face to engage gasket.

As the coupling assembly is made-up, the rim 70 engages the gasket 50, and relative rotation between the coupling member and gasket is thus prevented. A gland having a rim 70 thereon shaped to engage the gasket may be required to be used with another gland that also has a rim 70 thereon. The rims provide opposing forces on either side of the gasket to help each rim engage the gasket. Because the rim 70 is radially outwardly spaced from the center of the gland, it provides a good moment arm for preventing relative rotation between the gland and the gasket. Continued axial advancement of the coupling members 10. 12 toward one another and into compressed. sealing engagement with opposite faces of the gasket 50 ultimately results in gasket material being axially displaced into the recess 72, 74. The receipt of the gasket in the recesses 72, 74 provides a locking feature which assures that the gasket and the coupling member do not rotate relative to one another. even at elevated torque levels.

As the coupling members 36. 38 are advanced toward one another during make-up of the assembly. the gasket 50 forms a primary seal between the beads 60. Upon further make up. the radial portion of the gasket 50 between the bead 60 and the rim 70 is received in the cavity defined by the planar region 64. This cavity defined by the planar regions 64 is ultimately substantially filled with gasket material radially outward of the primary seal area of the beads 60. Once the gasket 50 engages the planar region 64, a substantial increase in torque is experienced by the user during make-up. This increase is related to the larger surface area of contact between the gasket and the coupling member. The gasket is less easily deformed when each gland applies more evenly distributed forces on the gasket. as opposed to the relatively concentrated forces when only the bead, or bead and rim, are contacting the gasket. Because the gasket deforms less easily, this provides the increased torque feedback to the user. Fig. 5 illustrates the increase in torque during make-up. Upper curve 80 illustrates the substantial increase in torque (y-axis) associated with the tube coupling assembly of the present invention as it is made-up. e.g.. turns past finger tight

("TPFT") (x-axis). Each unit on the x-axis represents a fraction of a full turn. A more conventional, prior art arrangement which exhibits a more linear increase is shown as bottom curve 82. Thus, the more rapid increase of the upper curve 80 relative to the lower curve 82 illustrates the positive feedback provided to the user during make-up. The feedback communicates that the desired amount of axial displacement of the glands has occurred. and make-up of the fitting is complete. When the substantial increase in torque is felt by the user, the preferred sealing pressure is applied to the gasket. Under this desired pressure. the gasket substantially fills any dead space disposed radially inward of the bead so that the made up coupling assembly minimizes the dead space volume. Thus a bore-line seal. or near bore-line seal is achieved. as shown in Fig. 2A.

Fig. 6 illustrates the universal adaptability of the present coupling assembly with existing systems. The first gland or coupling member 10 is of a shape and configuration as the coupling components described above. The second or right-hand gland or coupling member 10 is of a more common. conventional structure. That is. the bead 90 of the coupling member 10 is disposed at a radially median region of the enlarged diameter shoulder of the coupling member 10' The coupling member 10' lacks a peripheral rim and a substantially planar region that extends over a major portion of the seal face. In the made-up condition, the bead 90 of the second coupling member contacts the gasket 50 opposite of the planar region 64 associated with a new coupling member 1 0. The bead 90 of the coupling member If)' urges gasket material axially into the planar region 64 of the coupling member 10. Accordingly the design of the coupling member 10 provides compatibilit! with the more conventional coupling member 10 As components of existing coupling assemblies are necessarily replaced, the new-stvle coupling member 10 provides a wide compatibility with conventional coupling members already in use.

Figs. 7A and 7B demonstrate that the coupling assembly of the present invention is not limited to tube coupling arrangements. For example. an end face 20 of a block 92 such as a valve. regulator. etc. may be formed with the preferred bead shape 60. substantially planar region 64 and rim 70 configuration as described above. An annular. female opening 96 having internal threads 94 is shaped to receive a male nut to secure another gland to the block 92. The male nut engages the internal threads 94 integrally formed in the block 92 to urge the end faces of the coupling components together toward opposite faces of the gasket. The block illustrated in Figs. 7A and 7B has an embedded female opening. However. the end

face 20 may formed in the block 92 in other configurations. such as an embedded male gland.

or glands directly coupled to the block 92.

Yet another alternate gland design for use in the present invention is illustrated in Figs. 8-10 and Fig. 18. The gland 10 has a bead 102 that is considerably "flatter" than the previously-described embodiments, as the bead has a greater radius of curvature. The gland 10 also includes a chamfer 104 between the inner bore 22 and the bead 102, which helps to reduce buckling of the gland along its inner diameter when the coupling is made up. The gland 10 also includes a recessed region. or planar region 64. The planar region 64 provides a space into which the gasket 50 may be forced during overtightening of the fitting, and thereby increases the torque required to rotate the male and female nuts relative each other.

This increase in torque may help to protect the fitting from significant overtightening. and may provide feedback to the user that the fitting has reached its made-up condition. In the Fig. 10 embodiment. the planar region 64 includes radiused portions 108. 110 to create a smooth contour to the planar region 64.

The gland further includes a rim 70 extending axially forwardly the same distance as the bead 102. Thus. during make-up the rim 70 and bead 102 engage the gasket 50 at substantially the same time. The rim 70 may have recesses formed therein. as discussed earlier, to increase the engagement between the rim and the gasket 50. Alternately, the rim does not have any recesses, as the relatively smooth surface of the rim may provide sufficient frictional engagement with the gasket. However. the rim may also be knurled. roughened. or otherwise treated to increase the frictional engagement between the rim 70 and the gasket 50 if so desired. Forming knurling. roughening. recesses. or other such shapes in the rim 70 helps to allow fluid to escape from the coupling if the beads of the coupling members are not properly sealed with the gasket. If there is a leak between the beads and the gasket. it may be desirable to allow fluid to escape radially outward of the rim 70 so that the leak may be detected and corrective measures taken.

In further alternate embodiments shown in Figs. 11-16, the end face 20 of the gland does not include a protruding bead. but instead has a slight contour or radius of curvature 112 at its radial inner edge (Fig. 12). The gland 10 includes a body 11 having a sealing face or end face 20. and the end face 20 has an outer diameter 11 4 and an inner diameter 11 6. The inner diameter 11 6 defines the through bore 22 in the gland. The inner diameter 11 6 is axially recessed from the outer diameter 114, and the end face 20 has a curved or contoured surface adjacent 112 the inner diameter 116. In one embodiment. the curved surface 112 is

generally shaped as a portion of a circle. or arc, in side view. A generally planar surface 11 8 may be located adjacent the curved surface 112, although the curved surface may cover all of the end face 20 in one embodiment. As shown in Fig. 13. when in the made up condition, the contoured areas 112 curve away from the gasket 50, thereby decreasing the compression applied to the gasket 50 near its inner diameter 52. This arrangement helps to avoid placing undue stress on the gasket inner diameter 52. which may cause cracking or buckling of the gland at that surface.

As shown in Fig. 11. the end face 20 may further include a plurality of recesses 120 circumferentially spaced about its periphery. Each recess 120 forms an edge 122 to engage the gasket when the coupling component 10 is advanced toward and engaged with a second coupling component (not shown). The recesses 120 may be between about 0.007-0.030 inches in depth, preferably about 0.015 inches. Each edge 122 grips the gasket 50, and thereby helps to prevent relative rotation between the gasket and gland, and decreases transmitted torque. The recesses 120 also increase the break-away torque of the fitting. As will be discussed in greater detail below. the recesses may have a wide variety of shapes and sizes without departing from the scope of the invention.

Each gland further preferably includes a retainer-receiving portion 128, which is an annular notch located radially outward of the end face. As shown in Fig. 17, one of the glands 12 in a coupling arrangement A may have a retainer 124 mounted thereon. The retainer 124 receives a gasket 50 and maintains it in a proper orientation so that it is properly captured between the glands 10, 12 during makeup. The retainer 124 includes a radially- inwardly extending flange 126 shaped to radially overlap with the gasket 50. When the fitting is made up, the flange 126 is received in the retainer-receiving portion 128 of the gland 10. In this manner, the fitting may be made up, and the retainer 124 does not interfere with the sealing of the glands 10, 12 and the gasket 50.

Figs. 14-16 illustrate alternate embodiments of the glands of the present invention.

The glands in Figs. 14-16 have differing numbers and shapes of recesses 120 formed in the end face 20 of the gland 1 0. Although the illustrated embodiments show the recesses as generally scalloped" shaped, the recesses may be nearly any shape. including semi-circular.

square, rectangular. triangular, or other regular or irregular shapes. The illustrated "scalloped" shape may be convenient to manufacture, as a stationary mill may be used to remove material at each of the recesses (Figs 11, 14). A moving mill may also be used to remove material from the outer periphery of the end face. to form recesses having a different

shape (Figs. 15, 16). Yet another embodiment is shown in Fig. 19. In that embodiment, the gland 10 includes a rim 70. The rim 70 serves the same purpose as discussed earlier. as the rim is shaped and located to engage the gasket and helps to prevent relative rotation between the gland 10 and gasket 50.

Returning to Fig. 1 two glands 10. 12 are shown in abutting relation. When the female nut 34 is rotated to axially advance the glands toward each other, the rotation of the female nut 34 may cause a rotational force to be transmitted to the gland 12 inside the female nut. This rotational force may in turn be transmitted through the gasket 50 and into the gland 10 inside the male nut 36. If the gland 10 is rotated due to this transmitted force. such rotation may loosen other couplings or components upstream or downstream from the male nut 36. or may rotate and thus misalign other upstream or downstream components. In order to prevent this transmitted torque, the axial end 42 of the male nut 36 may be treated.

roughened, knurled or the like to improve the frictional engagement between the rear shoulder 1 8 and the adjacent gland 10. The male nut itself resists rotation because typically it is immobilized during the make up of the coupling, such as with a wrench engaging the flats 40. Of course, the rear shoulder 1 8 of the gland 10 may also be roughened or otherwise treated to increase the frictional engagement between the gland 10 and nut 36. As yet another embodiment, the male nut and male gland may be formed as a unitary or integral piece.

The invention has been described with reference to the preferred embodiments.

Obviously, changes and modifications will become apparent to those skilled in the art and the present invention is intended to cover such changes insofar as they fall within the scope of the appended claims. What is claimed is: