USRE44444E1 - Method of joining pipes in end to end relation - Google Patents

Abstract

A method for connecting pipe elements together end to end. The method includes providing a coupling having a plurality of segments with at least one camming surface, the segments being joined end to end by a plurality of adjustably tightenable fasteners, positioning a first and a second of the pipe elements in end to end relation, positioning the segments surrounding the ends of the pipe elements, engaging the camming surfaces on the segments with grooves on the pipe elements and tightening the fasteners so as to draw the segments toward one another. The camming surfaces slide into the grooves and move the first and second pipe elements away from one another.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 11/091,216 filed Mar. 28, 2005 now abandoned, which claims priority to U.S. Provisional Application No. 60/556,962, filed Mar. 26, 2004.

FIELD OF THE INVENTION

The invention concerns a method of using couplings for joining pipes in end to end relation and effecting a substantially rigid or a flexible fluid tight joint therebetween.

BACKGROUND OF THE INVENTION

Couplings for joining pipes together end to end comprise arcuate segments that circumferentially surround co-axially aligned pipes and engage circumferential grooves positioned proximate to the ends of each pipe. The couplings are also used to connect pipes to fluid control components such as valves, reducers, strainers, restrictors, pressure regulators, as well as components to components. Although in the description which follows pipes are described, they are used by way of example only, the invention herein not being limited for use only with pipes per se. It should also be noted that the term “pipe” as used herein refers to straight pipes as well as elbows, tees and other types of fittings.

The segments comprising the couplings have circumferential keys that extend radially inwardly toward the pipes and fit within the grooves around the pipes. The keys are typically somewhat narrower than the grooves to permit them to fit within the grooves and bear against the shoulders formed by the grooves to hold the pipes together against internal pressure and external forces that may be applied to the pipes. External forces may arise due to thermal expansion or contraction of the pipes due to changes in temperature as well as the weight of the pipes or components such as valves attached to the pipes, which can be significant for large diameter pipes and valves. Wind loads and seismic loads may also be a factor.

It is advantageous that pipe couplings be substantially rigid, i.e., resist rotation of the pipes relative to one another about their longitudinal axes, resist axial motion of the pipes relatively to one another due to internal pressure, and resist angular deflection of pipes relative to one another. A rigid coupling will be less likely to leak, requiring less maintenance, and will simplify the design of piping networks by eliminating or at least reducing the need for engineers to account for axial motion of pipes in the network when subjected to significant internal pressure. Pipes joined by rigid couplings require fewer supports to limit unwanted deflection. Furthermore, valves and other components which may tend to rotate out of position because their center of gravity is eccentric to the pipe axis will tend to remain in position and not rotate about the longitudinal axis under the pull of gravity when the pipe couplings are substantially rigid.

Many couplings according to the prior art do not reliably provide the desired degree of rigidity mainly because they use keys having rectangular cross-sections that are narrower than the width of the grooves that they engage. This condition may result in inconsistent contact between the coupling and the pipes which allows too much free play and relative movement, for example, axially, rotationally or angularly, between the pipes. It is also difficult to ensure that such keys properly engage the grooves. Couplings which provide a more rigid connection may be ineffective to force the pipe ends apart at a desired distance from one another so that the keys and grooves are in proper alignment and the pipes are properly spaced. When properly spaced apart, the pipe ends and the coupling cooperate with a sealing member positioned between the coupling and the pipe ends to ensure a fluid tight seal. The movement of the pipes, although small, is effected as the couplings are engaged with each other and the pipe and may require that significant torque be exerted upon the fasteners used to clamp the coupling to the pipes. This is especially acute when pipes to be joined are stacked vertically one above another, and the action of engaging the coupling with the pipes must lift one of the pipes upwardly relatively to the other in order to effect the proper spacing between the pipe ends. For such couplings, it is also difficult to reliably visibly ensure that the couplings have been properly installed so that the keys engage the grooves and the pipes are spaced apart as required to ensure a fluid tight seal.

It would be advantageous to provide a coupling that provides increased rigidity while also reducing the force necessary to engage the coupling with the pipe ends to effect their proper spacing, and also provides a reliable visual indication that the couplings are properly installed on the pipes.

SUMMARY OF THE INVENTION

The invention concerns a method for connecting pipe elements together end-to-end. The pipe elements have circumferential grooves proximate to each end. The method comprises:

• • providing a coupling comprising a plurality of segments joined end-to-end by a plurality of adjustably tightenable fasteners, each of the segments having a pair of keys projecting radially inwardly, the keys being positioned in spaced apart relation from one another and defining a space therebetween, at least one of the keys on one of the segments having a first camming surface positioned adjacent to one end of the segment, the first camming surface facing away from the space between the keys and being angularly oriented relatively thereto;
  • positioning a first and a second of the pipe elements in end-to-end relation;
  • positioning the plurality of segments surrounding ends of the first and second pipe elements;
  • engaging the first camming surface with the groove in one of the first and second pipe elements;
  • applying the fasteners to the segments; and
  • tightening the fasteners so as to draw the segments toward one another, the first camming surface sliding into the groove and thereby moving the first and second pipe elements away from one another.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a coupling for connecting two pipes end to end, the pipes being shown in phantom line;

FIG. 1A is a perspective view showing a detail of the coupling depicted inFIG. 1;

FIG. 2 is an exploded perspective view of the pipe coupling shown inFIG. 1;

FIG. 2A is an exploded perspective view of an alternate embodiment of a pipe coupling according to the invention;

FIG. 2B is a perspective view of a portion ofFIG. 2 shown on an enlarged scale;

FIG. 3 is a side view of a segment comprising the coupling shown inFIG. 1;

FIG. 4 is a bottom view of the segment shown inFIG. 3;

FIG. 4A is a side view of an alternate embodiment of a segment having one key and a flange for mating with flanged pipes or fittings;

FIG. 5 is a cross-sectional view taken at line5-5 ofFIG. 1;

FIGS. 5A and 5B are cross sectional views taken at line5-5 ofFIG. 1 showing alternate embodiments of the coupling according to the invention;

FIGS. 6 and 7 are side views of a roller tool forming a groove in a pipe;

FIGS. 7A-7G show side views of various embodiments of roller tools for forming a groove in a pipe;

FIG. 8 is a cross-sectional view of an alternate embodiment of the coupling;

FIG. 9 is a partial perspective view of an alternate embodiment of a coupling according to the invention;

FIGS. 10-15 are longitudinal sectional views of embodiments of pipes having circumferential grooves according to the invention; and

FIGS. 16-21 illustrate various fittings and components having circumferential grooves according to the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 shows apipe coupling10 for connecting twopipes12 and14 co-axially end to end. As shown inFIG. 2,coupling10 is comprised of at least twosegments16 and18. Eachsegment16 and18 haslugs20 and22 respectively, the lugs being positioned at or proximate to each end of the segments. Thelugs20 at each end ofsegment16 align with thelugs22 at each end ofsegment18.Lugs20 and22 are adapted to receive fasteners, preferably in the form ofbolts24 andnuts26 for joining the segments to one another end to end surrounding thepipes12 and14. In one embodiment, shown inFIG. 1, thelugs20 engage thelugs22 in what is known as “pad-to-pad engagement” with the lugs contacting one another when thesegments16 and18 are properly engaged with thepipes12 and14 as explained below. The lugs may also be attached to each other in spaced apart relation when thesegments16 and18 are properly engaged with thepipes12 and14, as illustrated inFIG. 1A.

Although lugs are the preferred means for attaching the segments to one another end to end, it is recognized that there are other attachment means, such as circumferential bands, axial pins, and latching handles. These means are disclosed in U.S. Pat. Nos. 1,541,601, 2,014,313, 2,362,454, 2,673,102, 2,752,174, 3,113,791, and 4,561,678, all of which are hereby incorporated by reference.

For large diameter pipes, it is sometimes advantageous to form thecoupling10 from more than two segments. As shown inFIG. 2A,pipe coupling10 comprisessegments16a and16b joined to each other and tosegments18a and18b, also joined to one another. Each segment again preferably haslugs20 and22 at each end thereof, the segments being joined to one another end to end by fasteners such asbolts24 and nuts26. The following description of thecoupling10 is provided by way of example, and is based upon a coupling having two segments with lugs at either end. Various aspects of the description are applicable to alternate embodiments regardless of the number of segments comprising the coupling or the manner in which the segments are attached to one another.

As shown inFIG. 2, eachsegment16 and18 has anarcuate surface28 facing inwardly towardpipes12 and14. Apair keys30 project radially inwardly from thearcuate surface28.Keys30 on each segment are in spaced apart relation to one another and define aspace32 between them. As best shown inFIG. 5, to effect the connection betweenpipes12 and14,keys30 engagegrooves34 and36 extending circumferentially aroundpipes12 and14 respectively. Engagement ofkeys30 withgrooves34 and36 substantially rigidly connect thepipes12 and14 coaxially to one another and maintain them at a predetermined separation as indicated by thegap38. A sealingmember40 is positioned withinspace32 and between thearcuate surfaces28 ofsegments16 and18 and thepipes12 and14. Thegap38 between thepipes12 and14 provides tolerance facilitating mounting of the coupling and allows pressurized fluid to apply hydraulic pressure to the sealingmember40 and ensure a fluid tight seal between thepipes12 and14.

As best shown inFIGS. 2 and 3, each key30 preferably has a pair of camming surfaces42 positioned adjacent to lugs20 and22 or otherwise near the ends of the segments. Camming surfaces42 preferably face outwardly away fromspace32 and are angularly oriented, as shown inFIG. 2B, with respect to anaxis43 oriented substantially tangential to the key30. The camming surfaces have anangular orientation45 that forms awedge46 adjacent to each lug, also shown inFIG. 4. As thesegments16 and18 are brought into engagement withgrooves34 and36 to connectpipe12 topipe14 as illustrated inFIG. 5, the camming surfaces42 (seeFIG. 2) are the first surfaces to engage thegrooves34 and36. Thewedge46 formed by the camming surfaces42 provides a mechanical advantage which forces thepipes12 and14 apart from one another as thelugs20 and22 ofsegments16 and18 are brought toward one another, preferably into pad-to-pad engagement. This wedging action ensures that aseparation gap38 between the pipe ends (seeFIG. 5) will be achieved when the connection between thepipes12 and14 is effected while reducing the force required to bring thelugs20 and22 toward each other.Lugs20 and22 are normally drawn toward each other by tightening nuts26 (seeFIG. 1). The mechanical advantage obtained by the use ofwedge46 significantly reduces the torque applied tonuts26 needed to bring thelugs20 and22 into pad-to-pad engagement to separate thepipes12 and14 by thegap38, and thereby allows large diameter, heavy pipes to be manually connected, even when stacked vertically above one another. Such configurations are a particular problem as the insertion of thekeys30 into thegrooves34 and36 must lift the entire weight of the pipe to form thegap38. Thewedge46 makes this effort significantly easier. Preferably, as shown inFIG. 2B, theangular orientation45 of camming surfaces42, as measured with respect toaxis43, is preferably about 5°, but may be up to about 10° for practical designs.

The use of keys having camming surfaces is not confined to couplings for joining grooved pipes to one another, but may be used on practically any coupling arrangement having at least one key.FIG. 4A shows acoupling segment51 used in conjunction with a similar coupling segment to attach grooved pipe to flanged pipe. Couplingsegment51 has an arcuate key30 withcamming surfaces42 at either end. As described above, the camming surfaces may be angularly oriented tangentially with respect to the key30 and form awedge46 as shown inFIG. 4. Opposite the key is aflange53 adapted to engage a mating flange on a flanged pipe. The flanges are secured via fasteners that pass though bolt holes55 as is understood for flanged connections. Thecoupling segment51 is attached end to end to its associated coupling segment by attachment means, preferably lugs20 positioned near the ends of the segment that align and are engaged by fasteners as is understood in the art and described above.

As best shown inFIGS. 5 and 5A,keys30 preferably have a shape that will effect a wedging action when they engagegrooves34 and36.FIG. 5 illustrates one configuration whereinkeys30 have a wedge-shaped cross section. Thekeys30 are defined by aninner surface50 facingspace32, anouter surface52 facing outwardly away fromspace32, and aradial surface54 positioned between the inner and outer surfaces and facing radially inwardly toward the pipes engaged by the coupling. Preferably, theinner surface50 is oriented substantially perpendicularly to theaxis48 andouter surface52 is oriented angularly relative to theaxis48 so as to form the wedge-shaped cross section ofkeys30. Therelative angle56, measured radially with respect to the key between theouter surface52 and anaxis48 oriented substantially co-axially with the longitudinal axes ofpipes12 and14, ranges up to about 70°, although 50° is preferred (see alsoFIG. 1).

Althoughsurfaces52 and54 inFIG. 5 are shown in cross-section as having a straight profile, they may be, for example, convex, concave or have some other profile shape and still effect a wedging action when engaged withgrooves34 and36. An alternate embodiment ofkeys30 is illustrated inFIG. 5A whereinsurface50 has a curved cross sectional profile in the form of a convex radius that substantially blends intoradial surface54.

As shown inFIG. 4, it is preferred that the radialangular orientation44 of camming surfaces42 be substantially equal to the radialangular orientation56 of the keyouter surface52 as measured relatively to thelongitudinal axis48. It is advantageous to match the radial orientation angles of the camming surfaces42 and the keyouter surfaces52 with one another to avoid point contact when the surfaces engage facing surfaces of thegrooves34 and36 as the coupling is installed in order to mitigate gouging between the surfaces that results from point to point contact.

Preferably, thegrooves34 and36 thatkeys30 engage have a shape that is complementary to the wedge-shape cross section of the keys. In general, it is advantageous that the keys have a cross sectional shape that substantially fills the grooves even when the shapes of the groove and key are not exactly complementary.Groove36 is described in detail hereafter, groove34 being substantially similar and not requiring a separate description.Groove36 is defined by afirst side surface58 positioned proximate to end14a ofpipe14, asecond side surface60 positioned in spaced apart relation to thefirst side surface58 and distally from theend14a, and afloor surface62 that extends between the first and second side surfaces. The complementary shape of thegroove36 to thekeys30 is achieved by orienting thefloor surface62 substantially parallel to theradial surface54, orienting thefirst side surface58 substantially perpendicularly to the floor surface62 (and thus substantially parallel to the inner surface50), and orienting thesecond side surface60 substantially parallel to the outer surface52 (and thus angularly to the floor surface62).

Preferably, thekeys30 and thelugs20 and22 are sized and toleranced so that when thelugs20 are in pad-to-pad engagement with thelugs22, i.e., in contact with each other as shown inFIG. 1, thekeys30 engage thegrooves34 such that the keys'outer surface52 is either just contacting thesecond side surface60 in what is called “line-on-line clearance” (see the left halt ofFIG. 5), or is in spaced relation to thesecond side surface60 of the groove, as defined by agap64 no greater than 0.035 inches (shown on the right half ofFIG. 5. Furthermore, theradial surface54 is also in either line on line clearance with the floor surface62 (left half,FIG. 5), or in spaced relation tofloor surface62, as defined by agap66 no greater than 0.030 inches (right half,FIG. 5). Theinner surface50 is nominally in contact with thefirst side surface58 as shown inFIG. 5, but there may be a gap there as well for certain tolerance conditions. As a practical matter, however, it is difficult and costly to make pipes and couplings perfectly round and to the exact dimensions desired, so that there will be intermittent contact between various surfaces of thekeys30 andgrooves34 and36 circumferentially around any pipe joint, creating an effectively rigid joint. Joint rigidity may be further augmented by the use ofteeth31 that project outwardly from the various surfaces ofkeys30 as best shown inFIG. 2.Teeth31 bite into the groove surfaces of the pipes, augmenting friction to help prevent rotational displacement of the pipes relatively to the couplings. The same relationships between the various surfaces mentioned above may also be achieved when the lugs are attached to one another in spaced apart relation as shown inFIG. 1A.

Analogous relationships between the key surfaces and the surfaces comprising the grooves are contemplated even when the keys do not have a shape complementary to that of the groove, as shown inFIG. 5A. Couplings having such keys, for example, the convex shaped key30, may havesurfaces52 that just contact thesecond side surface60 in line on line clearance (left side,FIG. 5A), or be in spaced relation to surface60 (right side,FIG. 5A), having agap64 between thesurfaces52 and60 of about 0.035 inches. Again, surfaces54 and66 may also be in line on line clearance or may be separated by agap62, preferably no greater than 0.030 inches.

Alternately, as shown inFIG. 5B, wedging action ofkeys30 may also be ensured wheninner surface50 andouter surface52 contact groove surfaces58 and60, respectively, butradial surface54 is in spaced relation to the groove'sfloor surface62 with agap66. The right side ofFIG. 5B shows various straight sidedkey surfaces50,52 and54 and counterpart straight sided groove surfaces58,60 and62 giving the groove and the key substantially complementary shapes. The left side ofFIG. 5B shows a convexly curvedouter surface52 engaging astraight surface60, as an example wherein the shape of the key and the groove are not substantially complementary. Note thatgroove floor surface62 is shown on the left side to be angularly oriented with respect to the surface ofpipe12.

It is found that the preferred configuration defined by pad-to-pad engagement oflugs20 and22 in conjunction with the tolerance conditions as describe above provides several advantages. The engagement ofinner surface50 withfirst side surface58forces pipes12 and14 into substantially precise axial position relative to one another. Because these surfaces bear against one another when the coupling is installed on the pipes they will not shift axially when internal fluid pressure is applied. Thus, designers need not take into account lengthening of the piping network due to internal pressure during use, thereby simplifying the design. The relativelysmall gaps64 and66 (which could be zero) ensure adequate rigidity and prevent excessive angular displacement between the pipes and the couplings, while the tolerances necessary to limit the gaps within the desired limits allow thecoupling10 to be manufactured economically. It also allows the grooves in the pipes, valves or other fittings to be manufactured economically. The gaps work advantageously in conjunction with the normally encountered out of roundness of practical pipes to provide a rigid joint. The pad-to-pad engagement oflugs20 and22 provides a reliable visual indication that thecoupling10 is properly engaged with thepipes12 and14.

If it is desired to have a moreflexible coupling10 to allow greater angular deflection, then thegaps64 at one or both ends of the coupling may be made larger than the aforementioned limit of 0.035 inches. For flexible couplings, it is found advantageous to havegap64 betweensurfaces52 and60 preferably be ½ of the size ofgap38 between the ends ofpipes12 and14 as shown inFIG. 5.

It is also feasible to havekeys30 engagegrooves34 and36 without a gap under all tolerance conditions. This configuration takes advantage of the wedging action of the keys to provide a rigid joint. It is not practical, however, to have this configuration and also maintain pad to pad engagement oflugs20 and22 because it is very difficult to economically manufacture couplings and pipes to the necessary tolerances to ensure both pad to pad engagement and full contact circumferential wedging engagement of the keys and grooves. For the configuration wherein pad-to-pad engagement is not nominally held, as shown inFIG. 9, it is preferred to employ atongue110 adjacent to thelug20 onsegment16 that fits into arecess112 adjacent to lug22 onsegment18. The tongue prevents sealingmember40 from blowing out through a gap between thelugs20 and22 when the joint is subjected to high internal pressure.

As illustrated inFIG. 6, groove36 is advantageously formed by cold working thematerial forming pipe14. In a preferred embodiment,groove36 comprises afirst side surface37 positioned proximate to the end ofpipe14, asecond side surface60 positioned in spaced apart relation to the first side surface and distally to the end of the pipe, and afloor41 that extends between the first and second side surfaces. Preferably, the second side surface is angularly oriented relatively to the floor at anangle43 that is than 90 degrees.

Aroller tool68 is used having a cross sectional shape at its periphery substantially identical to the desired shape of the groove. Theroller tool68 is forcibly engaged with theouter surface70 ofpipe14 around its circumference, either by moving the roller tool around the pipe or moving the pipe about itslongitudinal axis48 relatively to a roller tool. Preferably, a back-uproller72 engages theinner surface74 of thepipe14 opposite to theroller tool68. Thepipe wall76 is compressed between theroller tool68 and the back-uproller72. Use of the back-uproller72 provides a reaction surface for the roller tool. The back-up roller also helps ensure that accurate groove shapes are achieved by facilitating material flow during roll grooving.

During cold working to form thegroove36 having the angularly orientedsecond side surface60, it is found that significant friction is developed between theroller tool68 and thepipe14. The friction is caused by the contact between theangled surface78 on theroller tool68 that forms the angularly orientedsecond side surface60 ofgroove36. Because it is angled, points alongangled surface78 are at different distances from the axis ofrotation80 ofroller tool68. Due to their different distances from theaxis80, each of the points on thesurface78 will move relative to one another at a different linear speed for a particular angular velocity of theroller tool68. The points farthest from theaxis80 move the fastest and the points closest to the axis move the slowest. Thus, there is a velocity differential along theangled surface78 which causes the surface to slip relatively to thesecond side surface60 ofgroove36 as theroller tool68 rotates relatively to thepipe14 to form the groove. The relative slipping between the roller tool and the pipe causes the friction. Excessive heat caused by the friction can result in a break down of the roller tool bearing lubricants and make the roller tool too hot to handle when changing tools for a different size pipe. The roller tool must be allowed to cool before it can be changed, resulting in lost time.

To mitigate the generation of excessive heat, theroller tool82, shown inFIG. 7, is used to form agroove84 inpipe14. Ingroove84, thesecond side surface86 has afirst surface portion88 oriented angularly relative to thefloor surface90, and asecond surface portion92, positioned adjacent to thefloor surface90 and oriented substantially perpendicular to it, thereby reducing the size of the angularly orientedsecond side surface86. By reducing the size of the angled surface regions on both theroller tool82 and thegroove84 the friction caused during cold working to form the groove is reduced. Thefirst surface portion88, being angularly oriented, still provides the advantages as described above for thesecond side surface60. An example of acoupling10 engaging agroove84 is shown inFIG. 8.

Theroller tool82 has acircumferential surface94 with a cross sectional shape complementary to groove84, the shape comprising afirst perimetral surface99 oriented substantially perpendicularly to the axis ofrotation80 ofroller tool82, asecond perimetral surface98 positioned in spaced relation to the first perimetral surface96 and oriented substantially perpendicular to theaxis80, aradial surface100 extending between the first and second perimetral surfaces and oriented substantially parallel toaxis80, and anangled surface102 positioned adjacent to perimetralsurface100 and oriented angularly to theaxis80. Theangled surface102 is preferably oriented up to about 70° relatively toaxis80, and most preferably at about 50°.Surface102 slopes away from the second perimetral surface, thereby making contact with the pipe when forming thegroove84.

Wedging action between thekeys30 and grooves in the pipes can be achieved for groove cross sectional shapes other than those described above. The main criterion for wedging action is that the width of the groove at the surface of the pipe be greater than the width of the groove at the floor of the groove.FIGS. 10-15 show various groove configurations meeting this criteria.FIG. 10 shows agroove114 partially defined by aside portion116 having a concave cross sectional shape.FIG. 11 shows agroove118 partially defined by aside portion120 having a convex cross-sectional shape. InFIG. 12, thegroove122 is partially defined by aside portion124 having first and secondangled portions124a and124b, the firstangled portion124a having a greater slope than the secondangled portion124b.FIG. 13 shows agroove126 partially defined by aside portion128 having a firstangled portion128a with a slope less than the secondangled portion128b. Combinations of radius and angled portions are also feasible, as shown inFIG. 14, whereingroove130 has aradius portion132 and anangled portion134.FIG. 15 illustrates an example of agroove136 having a wedge-shaped cross sectional profile, there being no floor portion of any significance as compared with the other example grooves. Thegroove136 is defined byside portions136a and136b oriented angularly with respect to one another. Common to all of the designs is the characteristic that thewidth138 of the groove at the surface of the pipe is greater than thewidth140 of the groove at the floor of the groove. Note that, although it is preferred that the floor be substantially parallel to the pipe surface, it may also be curved, as shown inFIG. 10, or non-existent, as shown inFIG. 15, which has no floor, the floor width being essentially zero. The floor may also be angularly oriented as shown inFIG. 5B.

Roller tools for creating grooves as described above are shown inFIGS. 7A-7G. InFIG. 7A,roller tool101 is rotatable aboutaxis80 and has a radially facingsurface portion103 flanked by afirst surface portion105 and asecond surface portion107.Roller surface portion105 is preferably oriented perpendicularly toaxis80 and results in the formation of a substantially vertical groove side surface. Roller surface portion is concave and results in the convexgroove side surface120 as shown inFIG. 11.

Similarly,roller tool109, shown inFIG. 7B, has a radially facingsurface portion111 extending between aperpendicular surface portion113 and aconvex surface portion115. Such a roller produces a groove with aconcave side surface116 as shown inFIG. 10.

Additional roller embodiments117 and119, shown inFIGS. 7C and 7D, each have asurface portion121 with afirst face123 angularly oriented with respect toaxis80, and asecond face125, also angularly oriented with respect toaxis80, but at a different angle. Inroller tool117, the slope of the first surface portion is greater than the slope of the second surface portion, and this roller produces agroove122 as shown inFIG. 12. Inroller tool119, the slope of the first surface portion is less than the slope of the second surface portion, and this roller produces agroove126, having an angularly orientedside surface124 as shown inFIG. 13.

Roller tool127, shown inFIG. 7E, has no radially facing surface, anangled surface129 intersects with asurface portion131 that is substantially perpendicular to the axis ofrotation80.Roller tool127 is useful for creating the groove shown inFIG. 15.

Roller tool133, shown inFIG. 7F, has a curvedradially facing surface135 and an angularly orientedsurface135 as well as aperpendicular surface137. The curved surface may be convex, concave, sinusoidal, hyperbolic, or irregularly curved.

As shown inFIG. 7G, theroller139 may have aradially facing surface141 that is angularly oriented with respect to the axis ofrotation80. A groove as shown inFIG. 5B is produced by such a tool.

While grooves adapted to achieve significant wedging action with the keys of a coupling have been described applied to pipe ends, such grooves may also be used in conjunction with pipe fittings as well. For example,FIG. 16 shows anelbow fitting140 havingcircumferential grooves142 at either end.Grooves142 may have any of the cross sectional profiles illustrated in FIGS.5 and10-15 or their variations as described above. Similarly, the Tee fitting144 shown inFIG. 17 hasgrooves146, preferably adjacent to each of its ends, the grooves being adapted to develop wedging action to couple the fitting to pipes or other fittings as described herein.FIG. 18 shows a fitting148 having a wedginggroove150 adjacent to one end and aflange152 at the opposite end. Fitting148 allows a piping network using mechanical couplings to be joined to another network coupled using flanges. Furthermore, as illustrated inFIGS. 19 and 20, other types of fittings such as a reducer154 (FIG. 19) used to join pipes having different diameters, or a nipple156 (FIG. 20) may also benefit from havingrespective grooves158 and160 that are like those illustrated and described above that increase the wedging action between the coupling and the groove to ensure either a stiffer or more flexible joint, depending upon the tolerances of the coupling as described above.

As further shown inFIG. 21, components related to control of fluid flow, such as avalve162 may also havegrooves164 that are like those described above to couple the valve to pipes, fittings or other components using mechanical couplings as described herein.

Pipe couplings according to the invention incorporate the advantages of a rigid or flexible connection with a reliable visual indicator for confirming that the coupling properly engages the pipes to effect a fluid tight joint. The couplings provide a mechanical advantage which allows manual assembly of piping networks of substantial diameter despite their weight. The couplings have tolerances allowing them to be economically produced and still yield a substantially rigid joint between pipes.

Claims (22)

What is claimed is:

1. A method for connecting pipe elements together end-to-end, said method comprising:

using a pair of pipe elements, each having a circumferential groove therein, each said groove being positioned proximate to an end of a respective one of said pipe elements, each said groove having an angularly oriented side surface facing said end of said respective one of said pipe elements;

using a coupling comprising a plurality of segments joined end-to-end by a plurality of adjustably tightenable fasteners, each of said segments having a pair of keys projecting radially inwardly, said keys being positioned in spaced apart relation from one another and defining a space therebetween, at least one of said keys on one of said segments having a first camming surface positioned adjacent to one end of said segment, said first camming surface facing away from said space between said keys and being angularly oriented relatively thereto and having a radial orientation angle substantially the same as said angularly oriented side surface of one of said grooves;

positioning a first and a second of said pipe elements in end-to-end relation;

positioning said plurality of segments surrounding ends of said first and second pipe elements;

engaging said first camming surface with said angularly oriented side surface of said groove in one of said first and second pipe elements;

applying said fasteners to said segments; and

tightening said fasteners so as to draw said segments toward one another, said first camming surface sliding into said groove against said angularly oriented side surface and thereby moving said first and second pipe elements away from one another.

2. The method according toclaim 1, further comprising positioning a sealing member surrounding said ends of said first and said second pipe elements.

3. The method according toclaim 1, further comprising placing ends of said first and second pipe elements in abutting relationship.

4. The method according toclaim 1, further comprising forming a groove in each of said first and second pipe elements by forming a first side surface proximate to an end of said pipe elements, forming a second side surface positioned in spaced relation to said first side surface and distal to said end of said pipe, forming a floor that extends between said first and second side surfaces, said second side surface of said one groove comprising said angularly oriented side surface.

5. The method according toclaim 4, further comprising forming said first side surface substantially perpendicularly to a long axis of said pipe element.

6. The method according toclaim 5, further comprising further tightening said fasteners and thereby forcing said keys into said grooves.

7. The method according toclaim 6, further comprising contacting said first side surfaces in each of said grooves with said keys.

8. The method according toclaim 7, wherein said segments further comprise lugs positioned at each end thereof, said lugs being adapted to receive said fasteners, one of said lugs on each of said segments being in facing relation with one of said lugs on another of said segments, said method further including tightening said fasteners so as to bring said lugs in facing relation into contact with one another thereby forming a rigid joint.

9. A method for connecting pipe elements together end-to-end, said method comprising:

using a pair of pipe elements, each having a circumferential groove therein, each said groove being positioned proximate to an end of a respective one of said pipe elements, each said groove having an angularly oriented side surface facing said end of said respective one of said pipe elements;

using a coupling comprising first and second segments joined end-to-end by a plurality of adjustably tightenable fasteners, each of said segments having a pair of keys projecting radially inwardly, said keys being positioned in spaced apart relation from one another and defining a space therebetween, each of said keys having a first camming surface positioned adjacent to one end of said segment, and a second camming surface positioned adjacent to an opposite end of said segment, said camming surfaces facing away from said space between said keys and being angularly oriented relatively thereto and having a radial orientation angle substantially the same as said angularly oriented side surface of one of said grooves;

positioning a first and a second of said pipe elements in end-to-end relation;

positioning said first and second segments surrounding ends of said first and second pipe elements;

engaging said camming surfaces with said angularly oriented side surfaces of said grooves in said first and second pipe elements;

applying said fasteners to said segments; and

tightening said fasteners so as to draw said segments toward one another, said camming surfaces sliding into said grooves against said angularly oriented side surfaces and thereby moving said first and second pipe elements away from one another.

10. The method according toclaim 9, further comprising positioning a sealing member surrounding said ends of said first and said second pipe elements.

11. The method according toclaim 9, further comprising placing ends of said first and second pipe elements in abutting relationship.

12. The method according toclaim 9, further comprising forming a groove in each of said first and second pipe elements by forming a first side surface proximate to an end of said pipe elements, forming a second side surface positioned in spaced relation to said first side surface and distal to said end of said pipe, forming a floor that extends between said first and second side surfaces, said second side surface comprising said angularly oriented side surface.

13. The method according toclaim 12, further comprising forming said first side surfaces substantially perpendicularly to a long axis of said pipe element.

14. The method according toclaim 13, further comprising further tightening said fasteners and thereby forcing said keys into said grooves.

15. The method according toclaim 14, further comprising contacting said first side surfaces in each of said grooves with said keys.

16. The method according toclaim 15, wherein said segments further comprise lugs positioned at each end thereof, said lugs being adapted to receive said fasteners, one of said lugs on each of said segments being in facing relation with one of said lugs on another of said segments, said method further including tightening said fasteners so as to bring said lugs in facing relation into contact with one another thereby forming a rigid joint.

17. A method for connecting pipe elements together end-to-end, said method comprising:

using a pair of pipe elements, each having a circumferential groove therein, each said groove being positioned proximate to an end of a respective one of said pipe elements, at least one of said grooves having an angularly oriented side surface facing said end of said respective one of said pipe elements;

using a coupling comprising a plurality of segments joined end-to-end by a plurality of adjustably tightenable fasteners, each of said segments having a pair of keys projecting radially inwardly, said keys being positioned in spaced apart relation from one another and defining a space therebetween, at least one of said keys on one of said segments having a first camming surface positioned adjacent to one end of said segment, said first camming surface facing away from said space between said keys and being angularly oriented relatively thereto and having a radial orientation angle substantially the same as said angularly oriented side surface of said at least one of said grooves;

positioning a first and a second of said pipe elements in end-to-end relation;

positioning said plurality of segments surrounding ends of said first and second pipe elements;

engaging said first camming surface with said angularly oriented side surface of said at least one of said grooves in one of said first and second pipe elements;

applying said fasteners to said segments; and

tightening said fasteners so as to draw said segments toward one another, said first camming surface sliding into said at least one of said grooves against said angularly oriented side surface and thereby moving said first and second pipe elements away from one another.

18. The method according to claim 17, further comprising forming said at least one groove in at least one pipe element of said first and second pipe elements by forming a first side surface proximate to an end of said at least one pipe element, forming a second side surface positioned in spaced relation to said first side surface and distal to said end of said at least one pipe element, forming a floor that extends between said first and second side surfaces, said second side surface comprising said angularly oriented side surface.

19. The method according to claim 18, further comprising forming said first side surface substantially perpendicularly to a long axis of said at least one pipe element.

20. A method for connecting pipe elements together end-to-end, said method comprising:

using a pair of pipe elements, each having a circumferential groove therein, each said groove being positioned proximate to an end of a respective one of said pipe elements, at least one of said grooves having an angularly oriented side surface facing said end of said respective one of said pipe elements;

using a coupling comprising first and second segments joined end-to-end by a plurality of adjustably tightenable fasteners, each of said segments having a pair of keys projecting radially inwardly, said keys being positioned in spaced apart relation from one another and defining a space therebetween, at least one of said keys having a first camming surface positioned adjacent to one end of said segment, said first camming surface facing away from said space between said keys and being angularly oriented relatively thereto and having a radial orientation angle substantially the same as said angularly oriented side surface of said at least one of said grooves;

positioning a first and a second of said pipe elements in end-to-end relation;

positioning said first and second segments surrounding ends of said first and second pipe elements;

engaging said first camming surface with said angularly oriented side surface of said at least one of said grooves in said first and second pipe elements;

applying said fasteners to said segments; and

tightening said fasteners so as to draw said segments toward one another, said first camming surface sliding into said at least one groove against said angularly oriented side surface and thereby moving said first and second pipe elements away from one another.

21. The method according to claim 20, further comprising forming said at least one groove in at least one pipe element of said first and second pipe elements by forming a first side surface proximate to an end of said at least one pipe element, forming a second side surface positioned in spaced relation to said first side surface and distal to said end of said at least one pipe element, forming a floor that extends between said first and second side surfaces, said second side surface comprising said angularly oriented side surface.

22. The method according to claim 21, further comprising forming said first side surface substantially perpendicularly to a long axis of said at least one pipe element.

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