HK1100450B - Deformable mechanical pipe coupling - Google Patents

Description

Deformable mechanical pipe joint

Technical Field

The present invention relates to mechanical pipe joints that are deformable to conform to pipe elements, allowing the joints to be pre-assembled and assembled as a unit.

Background

A mechanical joint for joining pipe elements together end-to-end includes interconnectable segments positionable circumferentially about the ends of coaxially aligned pipe elements. The term "tube" is used herein to describe any tubular article or component having a tubular shape. Pipe fittings include tubing, pipe fittings such as elbows, caps and tees, and fluid control components such as valves, reducers, filters, restrictors, pressure regulators, and the like.

Each mechanical coupling segment includes a housing having an arcuate surface that projects radially inwardly from the housing and engages plain end pipe elements or a circumferential groove extending around each of the pipe elements to be joined. The engagement between the arcuate surfaces and the pipe elements provides mechanical restraint to the joint and ensures that the pipe elements remain coupled even under high internal pressure and external forces. The housing defines an annular channel that receives a gasket or seal, typically an elastomeric ring, that engages the pipe element ends and cooperates with the segments to provide a fluid tight seal. The segments have attachment members, typically in the form of lugs that project outwardly from the housing. The lugs are adapted to receive fasteners, such as nuts and bolts, which may be adjustably tightened to draw the segments toward one another.

To ensure a good fit between the coupling and the pipe elements, the arcuate surfaces on prior art couplings have a radius of curvature that substantially matches the radius of curvature of the outer surfaces of the pipe elements to be joined. For fittings used with grooved pipe elements, the radius of curvature of the arcuate surfaces is less than the radius of curvature of the outer surfaces of the pipe elements outside the grooves so that the arcuate surfaces fit properly within and engage the grooves.

In prior art couplings, this geometric relationship between the arcuate surfaces of the coupling and the outer surfaces of the pipe elements results in a tedious and time consuming installation process when using mechanical couplings. Typically, the technician accepts a joint where the segments are bolted together and the ring seal is retained within the channels of the segments. The technician first removes the coupling by unscrewing it, removes the ring seal, and applies the lubricating oil (if not previously lubricated) and positions it around the ends of the tubulars to be joined. Installation of the ring seal requires that it be lubricated and extended to accommodate the pipe elements, which is often a difficult and messy task, as the ring seal is often rigid and lubrication can make manual manipulation of the seal difficult. After the ring seal is placed in place on both pipe elements, the segments are placed one at a time straddling the pipe element ends and securing the ring seal thereagainst. During placement, the segments engage the seal, the arcuate surfaces are aligned with the grooves, the bolts are inserted through the lugs, the nuts are threaded onto the bolts and tightened, the coupling segments are pulled toward one another, compressing the seal and engaging the arcuate surfaces within the grooves.

As is apparent from the above description, the installation of mechanical pipe joints according to the prior art requires that the technician typically handle at least seven separate components (even when the joint has more than two segments) and must completely remove and reinstall the joint. Significant time, labor and expense can be saved if a technician can install a mechanical pipe joint without first completely removing the joint and then reinstalling it piece by piece.

Summary of The Invention

The present invention relates to interconnectable pipe coupling segments. Each segment is positionable straddling facing ends of a pair of pipe elements for securing the pipe elements together in end-to-end relationship. The end of the tube has an outer surface of generally cylindrical profile. Each segment includes a pair of arcuate surfaces adapted to engage the outer surfaces of the pipe elements. The arcuate surfaces are spaced apart from one another. The arcuate surfaces subtend an angle of less than 180 and have a radius of curvature greater than the radius of curvature of the outer surfaces of the pipe elements. Each segment further includes a connection member for adjustably connecting one joint segment to another joint segment. The connecting members may be adjustably tightenable for drawing the arcuate surfaces of the segments together. The segments are deformable by adjustable tightening of the coupling members to conform the curvature of the arcuate surfaces to the outer surfaces of the pipe elements.

Preferably, the segments are substantially elastically deformable, and the arcuate surfaces project radially inwardly from the segments. The connecting member includes a pair of projections extending outwardly from the ends of each segment. The projections are adapted to receive fasteners for adjustably connecting the segments to one another, the fasteners being adjustably tightenable for drawing the arcuate surfaces of the segments together into engagement with the outer surfaces of the pipe elements. Preferably, the projections comprise lugs having apertures therethrough adapted to receive fasteners.

The present invention also relates to pipe couplings positionable straddling facing end portions of a pair of pipe elements for securing the pipe elements together in end-to-end relationship. Also, the end of the tube has an outer surface of generally cylindrical profile. The pipe joint includes first and second joint sections. Each coupling segment has a pair of arcuate surfaces adapted to engage the outer surfaces of the pipe elements. These arcuate surfaces are spaced apart from one another. The arcuate surfaces subtend an angle of less than 180 and have a radius of curvature greater than the radius of curvature of the outer surfaces of the pipe elements. Each joint segment has a connection member for adjustably connecting one joint segment to another joint segment. The connecting members may be adjustably tightenable for drawing the arcuate surfaces of the segments together. The segments are deformable by adjustable tightening of the coupling members to conform the curvature of the arcuate surfaces substantially to the outer surfaces of the pipe elements.

A pipe joint further includes a flexible, resilient seal. The seal is preferably a generally circular ring having an inner diameter sized to receive the pipe elements. The seal is disposed between the arcuate surfaces of the first and second coupling segments. The seal has an outer diameter sized to position the first and second coupling segments in spaced apart relation from one another sufficiently to permit the pipe elements to be inserted between the first and second coupling segments into end-to-end relation. The seal is deformable when the coupling members are adjustably tightened to draw the arcuate surfaces together and conform the curvature of the segments to the outer surfaces of the pipe elements.

Preferably, each of the first and second segments further comprises a pair of angularly oriented surfaces disposed adjacent each of the connecting members. The angularly oriented surfaces on each segment have opposite slopes. The angularly oriented surfaces on one segment are in facing relationship with the angularly oriented surfaces on the other segment. The angularly oriented segments engage one another as the segments are drawn together and cause the segments to rotate relative to one another about an axis substantially perpendicular to the pipe elements. The effect of the segments being drawn together and rotated forces engagement between the arcuate surfaces and the grooves to provide rigidity about all axes of the joint.

In another embodiment, a pipe coupling includes an arcuate band having a first end and a second end in generally opposing relation. The ends are spaced apart from each other. The band surrounds and defines a central space. The first and second arcuate surfaces are mounted lengthwise along the belt on one side thereof. The arcuate surfaces are in spaced side-by-side relationship with one another and project generally radially inwardly into the central space. The arcuate surfaces have a radius of curvature greater than the radius of curvature of the outer surfaces of the pipe elements. The end of the tube can be inserted into the central space. The connecting members are mounted on the first and second ends of the segments. The connecting members may be adjustably tightenable for drawing the first and second ends toward one another. The band is deformable to allow the first and second ends to move toward each other upon adjustable tightening of the connecting members. The arcuate surfaces are thus brought into engagement with the outer surfaces of the pipe elements and the curvature of the arcuate surfaces substantially conforms to the curvature of the outer surfaces of the pipe elements.

The deformation of the band may be elastic, plastic, or may be facilitated by a hinge disposed between the first and second ends. The hinge allows the first portion of the strap to pivot relative to the second portion of the strap for receiving the tube within the central space.

The invention also includes a method of securing together opposite end portions of pipe elements in end-to-end relationship. The method comprises the following steps:

(A) providing a pipe coupling having a plurality of coupling segments connected to one another end-to-end about a central space, the coupling segments having arcuate surfaces adapted to engage the outer surface of a pipe;

(B) inserting an end of the tube into the central space; and

(C) the coupling segments are deformed so that the arcuate surfaces of the coupling segments conform in curvature to the outer surfaces of the pipe elements.

Brief description of the drawings

1-1B are longitudinal sectional views of a deformable mechanical pipe joint according to the present invention;

figures 2 and 3 are partial cross-sectional views of the pipe coupling of figure 1;

figures 4 and 5 are perspective views, partially cut away, of a seal that may be used with a pipe coupling according to the present invention;

6-7 and 8 are axial views of various pipe joint embodiments according to the present invention;

FIGS. 7A and 9-13 are longitudinal sectional views of pipe joint embodiments according to the present invention;

fig. 14 is a perspective view of a pipe joint according to the present invention;

FIG. 15 is a side view of the pipe coupling of FIG. 14;

FIG. 16 is a cross-sectional view taken along line 16-16 of FIG. 14;

figure 17 is an axial view, partially broken away, of a pipe coupling embodiment according to the invention;

FIG. 18 is an axial view of a pipe coupling embodiment according to the present invention;

FIG. 19 is an axial view of a pipe coupling embodiment according to the present invention;

figure 20 is an axial view, partially broken away, of a pipe coupling embodiment according to the invention;

FIG. 21 is a partial cross-sectional view of the pipe coupling of FIG. 20;

figure 22 is an axial view, partially broken away, of a pipe coupling embodiment according to the invention;

FIG. 23 is an axial view of a pipe coupling embodiment according to the present invention; and

fig. 24-26 are axial views of pipe joint embodiments according to the present invention.

Detailed description of the embodiments

Figures 1 and 2 show a pipe coupling 10 according to the present invention. Joint 10 is formed of joint segments 12 and 14, with joint segments 12 and 14 being interconnectable with one another so as to straddle end portions 16a and 18a of pipe elements 16 and 18 for securing the pipe elements together in end-to-end relationship. The respective outer surfaces 20 and 22 of the pipe ends are of generally cylindrical configuration.

The interconnection of the joint segments 12 and 14 is made by means of a connecting member, preferably in the form of lugs 24 and 26, as best shown in figure 2. Lugs are preferably provided at each end of each segment and project outwardly from the segment. The lugs 24 and 26 are positioned to face each other and are adapted to receive fasteners, preferably in the form of bolts 28 and nuts 30, which may be adjustably tightened and cooperate with the lugs 24 and 26 for adjustably connecting the coupling segments to each other as described in further detail below.

As best shown in fig. 1, each segment 12 and 14 includes a pair of arcuate surfaces 32 and 34. The arcuate surfaces are spaced apart from one another and preferably project radially inwardly toward pipe elements 16 and 18. The surface extends from a housing 36 having side walls 38 joined to a rear wall 40, the side and rear walls forming a channel 42 that receives a seal 44.

An example of a seal 44 is shown in fig. 4 and 5. The seal 44 is preferably a flexible, resilient ring formed of an elastomeric material. The seal may have lips 46 that utilize internal pressure within the pipe to increase the sealing force between the seal and the outer surfaces 20 and 22 of pipe elements 16 and 18. As shown in fig. 5, the seal 44 may also have a tongue 48 between the lips 46 that extends circumferentially around the seal and projects radially inward. Tongue 48 provides a stop surface that engages the ends of pipe elements 16 and 18 to ensure proper positioning of seal 44 relative to the pipe elements, as described in further detail below. Engagement of the pipe elements with tongues 48 also effects alignment of the arcuate surfaces with the grooves, if present, or with alignment marks on the outer surfaces of the pipe elements.

As shown in fig. 2, the radius of curvature 50 of arcuate surfaces 32 and 34 is greater than the radius of curvature 52 of outer surfaces 20 and 22 of pipe elements 16 and 18. In addition, the arcuate surfaces 32 subtend an angle 54 of less than 180. An angle 54 between about 40 and about 179 is practical. As a result of this arcuate surface geometry, segments 12 and 14 may each be individually pre-assembled so that pipe elements 16 and 18 may be inserted directly into joint 10 shown in figure 1 without first removing the joint.

This feature provides a much superior advantage over prior art fittings which must be installed piece by piece on the pipe end. The joining of the pipe ends to the fitting 10 according to the invention can be performed more smoothly and more quickly than in the prior art fittings, because the technician has to deal with fewer parts and does not have to thread nuts onto bolts. In the embodiment shown in FIG. 1, the seal 44 has an outer diameter 56 that is sized to retain the coupling segments 12 and 14 in a spaced apart relationship sufficient to allow pipe ends to be inserted as described above. The seal inner diameter 58 is sized to receive the ends 16a and 18a of the pipe elements simply by pushing the fitting onto the pipe elements or by inserting the pipe elements into the fitting. Other embodiments having different features for supporting the segments in spaced apart relation are described below.

After the pipe elements 16 and 18 are inserted into the fitting 10 of fig. 1A, the nut 30 (see also fig. 2) is tightened. The nut 30 cooperates with its bolt 28 to pull the arcuate surfaces 32 and 34 on segment 12 toward the arcuate surfaces on segment 14. Tightening of the nuts exerts a force on lugs 24 and 26 which causes the segments to contact the pipe elements and causes segments 12 and 14 to deform so that the radius of curvature 50 of arcuate surfaces 32 and 34 substantially conforms to the radius of curvature 52 of pipe elements 16 and 18. This action is illustrated by comparing figures 2 and 3 with figures 1A and 1B in which the spacing 60 between the arcuate surface and the outer surface of the pipe is reduced as the arcuate surface engages the outer surface of the pipe end. The deformation of the segments 12 and 14 is preferably substantially elastic, allowing the segments to spring back substantially to their original shape when the nut 30 is loosened, thus allowing the fitting 10 to be reused in the manner described herein in accordance with the present invention. The segments may also be designed to have significant plastic deformation, wherein such deformation permanently deforms the segments. For a utility joint, some degree of plastic and elastic deformation occurs in the segments as a result of tightening the fastener. Additionally, the lugs 24 and 26 may form an angular orientation with respect to each other when the segments 12 and 14 are in an undeformed state (FIG. 2). Relative angles 62 of up to about 10 are practical. As shown in FIG. 3, as the segments deform, the relative angular orientation of the lugs 24 and 26 decreases, and the geometry may be designed such that once the arcuate surfaces 32 and 34 substantially conform to the outer surfaces 20 and 22, the lugs are substantially parallel. This is preferred because, upon full tightening, the bolt head and nut will be in substantially planar contact with the lugs, thereby avoiding reducing bending moments in the bolt which could result in permanent deformation of the bolt. The seal 44 is also deformed by this process as shown in figure 1B wherein the lips 46 fully engage the pipe element outer surfaces 20 and 22. Because the seal 44 is substantially incompressible, space must be provided for the seal to expand when compressed by the segment. This space is provided by a recess 64 provided in the rear wall 40 between the side walls 38. The concavity 64 may take virtually any practical shape and allows the seal to undergo a volume change when heated or exposed to a fluid, thereby distributing the deformation of the seal more evenly over its perimeter and mitigating the tendency of the seal to extrude outwardly from between the segments between the lugs. The concavity also prevents tongue 48, if any, from being forced between the pipe ends and impeding the flow of fluid therethrough.

As shown in fig. 2 and 3, for the preassembled fitting 10, it is advantageous to hold the nut 30 in place on the bolt 28, with the bolt 28 holding the segments 12 and 14 in the desired spaced apart relationship, as determined by the contact between the segments and the seal 44. This can advantageously be achieved by deforming the thread 29 of the bolt 28, preferably by riveting. Riveting the bolts prevents rotation of the nuts and prevents them from being unscrewed from the bolts, for example during shipping, due to the effects of vibration, and holds the joint in a pre-assembled condition with all its parts held together prior to installation. The riveting is easily overcome when the nut is tightened by a wrench.

The bending stiffness of the segments can be adjusted to control the amount of force necessary to deform them, thereby reducing the required assembly torque and reducing wear between the nut and the lugs. As shown in FIG. 6, the increased bending flexibility segments 66 may be formed in the outer shell 36 of the segments 12 and 14 by reducing the area of the moment of inertia of the segments. This reduction is preferably accomplished by adding one or more cutouts 68 in the back wall 40 and the arcuate surfaces 32 and 34.

Alternatively, as shown in FIG. 7, the segments may have arcuate surfaces 32 and 34 (not shown) that include inwardly projecting teeth 69. Teeth 69 engage the outer surface of the pipe elements to provide mechanical restraint and are particularly advantageous when used with plain end pipe elements. Teeth 69 may be continuous, as shown on segment 14, or intermittent, as shown on segment 12. A single tooth, preferably for a small joint, is also possible. As shown in fig. 7A, teeth 69 may also be provided in pairs on opposite sides of the segment to increase the mechanical constraint provided by the joint.

Although the joint according to the invention is described above as comprising two segments, this is only an exemplary way. Joints with more than two segments are also feasible and preferred for larger diameter pipes due to manufacturing costs, since reducing the diameter of the segments is economically advantageous. Another advantage is that the spacing between the lugs is reduced, requiring fewer turns of the nut and shorter bolts. Standard depth sockets can be used during installation. Fig. 8 shows an example of a joint embodiment 72 having four segments 74 similar to those described above.

Thus, a joint is shown in which all of the arcuate surfaces have substantially the same radius of curvature. While this configuration is suitable for use with connection pipes having diameters that are substantially the same as each other, figure 9 shows a coupling embodiment 76 for coupling pipes of different diameters. The joint 76 is formed of two segments 78 and 80 (although there may be more than two segments). Each segment has a first arcuate surface 82 with a first radius of curvature 84, and a second arcuate surface 86 with a second radius of curvature 88 that is less than the first radius of curvature 84. This allows the coupling 76 to connect a larger diameter tubular member 90 to a smaller diameter tubular member 92. Similar to the joint described above, the radius of curvature 84 is greater than the radius of curvature of the outer surface of the pipe element 90 and the radius of curvature 88 is greater than the radius of curvature of the pipe element 92. This geometric relationship allows the pipe elements 90 and 92 to be inserted into the pre-assembled fitting 76 and achieves the advantages of the present invention. The coupling segments 78 and 80 are deformed by the adjustable coupling members applying a force to conform the radius of curvature to the outer surface of the pipe elements.

In a preferred embodiment, the inwardly projecting arcuate surfaces 32 and 34 of the coupling 10 engage grooves 94 formed in the outer surfaces 20 and 22 of the pipe element ends 16a and 18a, as shown in figure 10. The interaction between the arcuate surfaces 32 and 34 and their respective grooves 94 allows the joint to provide high end restraint against forces caused by internal pressure or external loads. To achieve higher end constraint, it has been found that a second set of arcuate surfaces can be added that interact with a second set of grooves in the pipe elements. This embodiment is shown in fig. 11, in which the joint 96 includes segments 98 and 100, each having two pairs of arcuate surfaces 102 and 104 projecting inwardly from the segments. The pairs of arcuate surfaces are substantially parallel to and spaced apart from each other and engage pairs of grooves 106 in the surfaces of the pipe elements 108 and 110 to which they are attached.

In another embodiment, as shown in FIG. 12, for example, the coupling 10 according to the present invention may be used with pipe elements 112 and 114 having raised circumferential shoulders 116, the shoulders 116 being brought into engagement by the arcuate surfaces 32 and 34 of the segments 12 and 14. Alternatively, as shown in FIG. 13, a coupling 118 according to the present invention has segments 120 and 122 with respective arcuate surfaces 124 and 126 for use with pipe elements 128 and 130 having flared ends 132 and 134. It should be noted that in the exemplary embodiment shown in figures 9-13, the seal 44 has a tongue 48 which is effective for positioning the pipe end within the fitting by insertion, the tongue acting as a pipe stop to help position the pipe end at the correct depth within the fitting.

Another coupling embodiment 136 is shown in fig. 14. The connector 136 includes two segments 138 and 140 with lugs 142 and 144 extending therefrom that cooperate with fasteners 146 to serve as connecting members for adjustably connecting one connector segment to another. As described above, each segment has a pair of arcuate surfaces 148, 150 each preferably projecting radially inwardly from the segment. The arcuate surfaces subtend an angle 152 of less than 180 and have a radius of curvature 154 greater than the radius of curvature of the pipe elements with which the joint is to be joined. Anti-rotation teeth 70 are disposed adjacent the arcuate surfaces and project radially inwardly to engage the pipe elements and provide torsional rigidity.

As best shown in fig. 14, each segment 138 and 140 has a pair of angularly oriented surface portions 156 and 158 positioned adjacent each lug 142 and 144. As shown, the slope of the surface portion 156 may be opposite to the slope of the upper surface portion 158 of each segment. (these two surfaces may also be inclined in the same direction). This opposite slope relationship between the upper surfaces of the segments results in the surfaces having the appropriate slopes to be disposed in the pre-assembled coupling in opposing relationship, as shown in fig. 15. When the fasteners 146 are tightened to conform the arcuate surfaces to the outer surfaces of the pipe elements, the angled surface portions 156 and 158 on each segment engage and slide relative to each other causing the segments to be drawn together and rotated relative to each other in opposite directions about an axis 160, the axis 160 being oriented substantially perpendicular to the axis of the pipe elements to be joined. These movements of segments 138 and 140 cause arcuate surfaces 148 and 150 to engage the grooves in the pipe elements and add stiffness to all of the nodal axes described above. For coupling segments having surface portions with the same slope, the couplings move in opposite directions along the pipe relative to each other with a similar effect.

As shown in the cross-sectional view of fig. 16, the segments 138 and 140 forming the joint 136 have a channel 162 defined by a housing 164. The housing is formed by a rear wall 166 and side walls 168 and houses a seal 170 dimensioned to position the segments 138 and 140 in spaced apart relation to permit insertion of the pipe elements into the preassembled fitting shown in figure 14. A recess 172 is provided in the rear wall to provide space for seal volume changes when the seal is heated or exposed to fluid, and to prevent tongue 48 from being forced between the pipe ends and flow therethrough due to seal compression.

In another coupling embodiment, as shown in fig. 17, the coupling 174 again includes at least two coupling segments 176 and 178 each having an inwardly projecting arcuate surface 180 as described above. However, arcuate surface 180 has recesses 182 and 184 provided at opposite ends. The recesses 182 and 184 provide clearance at the 3 o 'clock and 9 o' clock positions of the coupling where it is most desirable to allow pipe elements to be inserted into the pre-assembled coupling 174. The increased clearance achievable at these locations allows the joint segments 176 and 178 to be spaced closer to each other in the preassembled configuration than if the clearance could not be achieved at the surface ends. By bringing the segments of the preassembled fitting closer together, the amount of deformation required to conform the arcuate surfaces to the outer surfaces of the pipe elements is reduced, thereby reducing the amount of energy required to tighten the fasteners.

Another coupling embodiment 192 according to the present invention is shown in fig. 18. The joint 192 includes an arcuate band 194 surrounding a central space 196. Band 194 has opposite ends 198 and 200 disposed opposite one another. The ends 198 and 200 are in spaced apart relation in the preassembled fitting and have attachment members mounted thereon, preferably in the form of projecting lugs 202 and 204 adapted to receive fasteners such as bolts 206 and nuts 208. The bolt and nut cooperate with the lugs to deform the band 194 and to draw the ends 198 and 200 toward one another after the pipe elements have been inserted into the central space 196 to form a connection in end-to-end relationship. The band 194 has a pair of arcuate surfaces 210, only one of which is visible in the figure. The arcuate surfaces are in spaced relation to one another lengthwise as shown in fig. 10 and described above for other embodiments. The arcuate surface 210 has a radius of curvature greater than the outer surface of the pipe ends to be joined together with the coupling. This geometric configuration and separation of ends 198 and 200 allows the pipe elements to be inserted into central space 196. Upon tightening of the nut 208, the band 194 is deformed such that the radius of curvature of the arcuate surfaces 210 is forced to conform to the radius of curvature of the outer surfaces of the pipe elements with which it is engaged. It should be noted that in the preassembled state, protruding lugs 202 and 204 are preferably angularly oriented relative to each other and have a relative angle 212 of up to about 20 °. Tightening of the fastener draws the lugs toward one another and causes the relative angle 212 to decrease to a point preferably where the lugs are substantially parallel to one another. This is particularly advantageous when used in flexible joints which do not form reaction points in response to pipe deformation leading to deformation with the bolt, where the resulting friction inhibits flexibility.

Coupling 192 includes a seal 214 disposed within band 194 and between arcuate surfaces 210. The seal 214 may be similar to the seal shown in fig. 4 and 5 and sized to receive a pipe element for forming a fluid tight seal when the band is deformed.

The bending flexibility of joint 192 may be adjusted by reducing the area of moment of inertia of band 194. This adjustment may be made by providing a slit 216 in the strap. Alternatively, as shown in FIG. 19, a hinge 218 may be provided between ends 198 and 200. Hinge 218 is preferably disposed equidistant from the ends of the strap and provides infinite bending flexibility, thereby reducing the torque on the fastener required to pull ends 198 and 200 toward one another. The band 194 will still deform when the arcuate surfaces 210 engage the outer surfaces of the pipe elements to conform the radius of the surfaces to the radius of the outer surfaces of the pipe elements. When a hinge is present, seal 214 is sized to maintain lugs 202 and 204 in a spaced apart relationship so that pipe elements can be inserted. For hinged and hingeless joints as described above, the arcuate surfaces preferably project radially inward from the band and may have different radii of curvature from one another, as shown in FIG. 9, to allow joint 192 to be used to join pipes having different diameters.

Figure 20 shows a pre-assembled coupling 220 which does not rely on a seal 222 to maintain its segments 224 and 226 in spaced apart relation and which readily accommodates pipe elements such as 228. The joint 220 has spacers 230 that extend between and hold the segments 224 and 226 in spaced apart relation. In the exemplary embodiment, spacer 230 includes a telescoping tube 232 that is disposed between opposing lugs 234 and 236 that extend from the segments. Tube 232 preferably has a thin wall and circular cross-section and is coaxially disposed about fastener 238. The tube may be made of a lightweight metal or polymeric material, such as polypropylene, and may have score lines 240 on its surface to create weakened zones that facilitate collapse of the tube under compressive loads applied by the fasteners 238. Other materials such as cardboard and rubber are also possible. The tubes are designed to be strong enough to support the segments in spaced apart relation during shipping, handling and installation, but to collapse under a predetermined compressive load that a technician can apply, preferably by manually tightening the fasteners with a wrench.

In use, pipe elements to be joined together end to end are inserted between segments 224 and 226. The fasteners 238 are then tightened to draw the segments toward one another into engagement with the pipe elements. Tightening of the fasteners places the tubes 232 under a compressive load and the tubes buckle and collapse when a predetermined load is reached as shown in figure 21 to allow the segments to move toward each other and engage the pipe elements for joining.

Spacers disposed between segments may be used with any type of mechanical joint. It should be noted in figures 20 and 21 that the segments 224 and 226 have arcuate surfaces 242, the radius of curvature of the arcuate surfaces 242 being substantially the same as the radius of curvature of the outer surfaces of the pipe elements 228 with which they are designed to engage. To provide clearance between the pipe elements 228 and the segments to allow the pipe elements to be inserted into the joint while still maintaining a proper fastener length, recesses 244 and 246 are provided at opposite ends of the arcuate surfaces 242, as best shown in figure 20. The recesses provide clearance at the 3 o 'clock and 9 o' clock positions of the coupling to allow pipe elements to be inserted into the pre-assembled coupling 220.

Fig. 22 shows another coupling embodiment 254 having spacer blocks 230 between segments 256 and 258 comprising couplings. In this example, the spacer 230 includes a tube 260, which is also disposed coaxially with a fastener 262 and between opposing lugs 264 and 266 projecting from the segment. The tube 260 has corrugations 268 that facilitate compression of the tube when a compressive load is applied by tightening the fastener. It should be noted that the segments 256 and 258 are similar to the segments described above with respect to figures 1 and 2, with the arcuate surfaces of the segments having a greater radius of curvature than the pipe elements.

Another example of a spacer for maintaining the coupling segments in spaced relation is shown in fig. 23. The fitting 270 includes segments 272 and 274 having outwardly projecting lugs 266 and 268, the lugs 266 and 268 being disposed in facing relation when the fitting is pre-assembled. The segments are held together by fasteners 280 extending between the lugs. A spacer 282, preferably in the form of a block-shaped body 284, is provided between the lugs 266 and 268. The body 284 is removable from between the lugs to allow tightening of the fasteners and tightening of the segments into engagement with the pipe elements to be joined.

The body 284 may be releasably connected to the segments, for example, held together by friction between the lugs 266 and 268. Flexible, resilient materials are particularly advantageous for forming the body because bodies made of such materials provide sufficient strength and rigidity to maintain the joints in spaced apart relation during rough handling, but at the same time are readily deformable for easy removal as required. If a polymeric material is used to form the body, the body may be bonded to the lugs by heat welding or by an adhesive which may provide a releasable bond between the body and the segments.

Figure 24 shows a non-deformable coupling embodiment 286 employing spacers 288 to maintain coupling segments 290 and 292 in spaced apart relation so that pipe elements may be inserted between coupling segments 290 and 292 in a pre-assembled state as shown. The coupling 286 is free of recesses or other features that may provide assistance in inserting pipe elements into the gap between the segments in end-to-end relation, but relies on the spacers to provide sufficient separation to provide sufficient clearance. The spacer 288 may be similar to the spacer described above.

Spacers according to the invention may also be used with various other types of joints. As shown in fig. 19, spacers 288 may be used in hinged joint embodiment 192 to maintain lugs 202 and 204 in spaced apart relation so that pipe elements may be inserted. Although tubular spacers are shown, it is understood that any of the spacers described herein may be used in such a joint.

Fig. 25 shows a reducing coupling 294 for joining flanged pipes to non-flanged pipes, such as grooved or plain-ended pipes. The coupling 294 includes coupling segments 296 and 298, each having a radially extending flange 300 on one side and an arcuate surface 302 on the opposite side. The segments 296 and 298 are held in spaced apart relation by a spacer 304, which spacer 304 may comprise a telescoping tubular spacer 306 or a removable spacer 308, or other types of spacers as described herein.

Figure 26 illustrates another type of spacer embodiment 310 that may be used to maintain joint segments 312 and 314 in a spaced apart relationship. Spacer 310 includes a spring member that preferably deforms substantially elastically when subjected to pressure applied by fastener 316. The spring member may take any of a variety of forms, such as a rubber cylinder 318 or a coil spring 320. The spring members used in the spacers allow for precise control of the force required to pull the segments toward each other and also facilitate reuse of the joint when the deformation of the spring members is substantially elastic.

It is contemplated that the deformable joint may also include other features, such as tongues and recesses disclosed in U.S. patent nos. 6170884 and 6302450; outlets incorporated into the segments, such as disclosed in U.S. patent No. 3362730; plain end fittings that do not use grooves are disclosed in U.S. patent nos. 2439979, 3024046, 5911446 and 6302450, all of which are incorporated herein by reference.

The deformable mechanical pipe joint according to the invention provides a quick and reliable installation for making a pipe connection without having to partially or completely disassemble and subsequently reassemble and handle the individual components.

Claims (1)

1. A method for securing together opposite end portions of pipe elements in end-to-end relationship, wherein said end portions of said pipe elements have an outer surface of generally cylindrical profile, said method comprising the steps of:

providing a pipe coupling having a plurality of coupling segments connected to one another end-to-end about a central space, the interconnection of the coupling segments being made by adjustable tightening bolts and nuts provided at each end of each coupling segment, the coupling segments having arcuate surfaces adapted to engage the outer surface of the pipe, the pipe coupling further having a flexible, resilient seal provided between the coupling segments, the seal having an inner diameter sized to receive the pipe elements, the seal having an outer diameter sized to support the coupling segments and position the coupling segments in spaced relation to one another to permit the pipe elements to be inserted between the coupling segments in the end-to-end relation;

inserting the end of the tube into the central space; and

deforming the coupling segments so as to conform the curvature of the arcuate surfaces of the coupling segments to the outer surfaces of the pipe elements while deforming the seal.