CA2931785A1

CA2931785A1 - Re-enforeced stiffening rings with tappered groves and tappered alignment ring for coupling systems

Info

Publication number: CA2931785A1
Application number: CA2931785A
Authority: CA
Inventors: Darcy L. Beaumont
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-06-01
Filing date: 2016-06-01
Publication date: 2017-12-01
Anticipated expiration: 2036-06-01
Also published as: CA2931785C

Abstract

Mechanical pipe couplings for joining pipe elements in end to end relation having keys which engage circumferential grooves on re-enforced rings which attach to piping ends.
The re-enforced rings have a slotted groove on the inside face to accommodate tapered alignment rings which eliminate or significant reduce misalignment issues. The coupling segments have re-enforced threated holes to accommodate monitoring sensors.

Description

FIELD OF THE INVENTION
The invention concerns mechanical couplings for joining large diameter pipe elements in end-to-end relation.
BACKGROUND OF THE INVENTION
Large diameter piping systems are becoming a more common method to transport coal, ore and tar sands. These raw materials are turned into slurries by adding water. These slurries are then transported through large diameter piping systems.
Individual lengths of pipe are connected together to create a piping system.
These individual lengths of pipe were typically connected using flange type connections.
However, when you are managing large piping systems a coupling system can provide many advantages over traditional flanges. Couplings can be fit up and connected much quicker as they can have as few bolts as 2 or 4. Flanges can have up to 28 studs and nuts on a 30" flange which need to be carefully torqued in sequence and to spec.
The process to connect a coupling is significantly easier.
In situations where the slurry is highly abrasive such as the tar sands, it is necessary to rotate the piping systems a quarter turn after so many hours of operation. The greatest wear in the piping systems occurs at the 6 o clock position. Turning the pipe increases the life expectancy of the piping system and reduces the possibility of a catastrophic failure should the slurry wear completely through the piping system. The need to continuously rotate the piping system makes the coupling system more desirable over traditional flange type connections.
However, misalignment of the pipe ends is a huge issue. Misalignment of pipe ends creates excessive wear at the connections or slightly downstream from the connections.
This issue generates excessive wear in concentrated locations and could result in a catastrophic failure of the piping system or accelerated erosion.
Many factors contribute to misalignment issues including but not limited to:
out of round pipe, poorly fitted coupling segments, improper coupling installation, poor maintenance, bolts and nuts that loosen due to thermal cycling and excessive stress due to moving several sections of connected pipe. It is common a practice to rotate slurry piping systems.
To save time several connected sections of pipe are moved together. This stress causes misalignment issues and loosening of fasteners. Misalignment includes axial, angular and lateral.
Adding a re-enforcing stiffening ring over the pipe will correct any out of round issues.
Adding a tapered groove to the inside face of the re-enforcing rings which is fully or partially filled with a tapered alignment ring ensures perfect alignment and allows for better fitment of the coupling segments during installation, normal operation and during movement of multiple sections of connected pipe. The tapered alignment ring improves alignment of the pipe ends even if the bolts and nuts loosen slightly.

2 Another issue with these large piping systems is leakage at the joints. This can be caused by loosening bolts and nuts which hold the coupling segments together. To address this issue, re-enforced platforms with threaded holes are added to the outside of the coupling segments. These re-enforced platforms with threaded holes accommodate monitoring sensors such as pressure. The sensors add a layer of safety and an early warning system that maintenance is required.
SUMMARY OF THE INVENTION
The invention consists of a coupling system for connecting two pipe elements together end to end. Each pipe end has a re-enforced ring with a circumferential groove proximate to an end thereof and a tapered groove on the inside faces to accommodate a tapered alignment ring. The coupling system comprises a plurality of segments position able end-to-end circumferentially around the pipe elements. Each coupling segments have a re-enforced platform, a pair of keys projecting radially inwardly toward the pipe elements with re-enforcing stiffening rings and a pair of stiffening ribs projecting radially outwardly. Each of the keys is engage able with the circumferential grooves of the re-enforcing stiffening rings on the ends of the pipe elements. The keys are positioned in spaced apart relation from one another and define a space there between. Each of the ribs is also positioned in spaced apart relation and each rib may be aligned with a respective key. At least one of the keys on one of the segments has first and second camming surfaces oppositely disposed and positioned adjacent to one end of the segment. The first camming surface faces away from the space between the keys, the second camming surface faces toward the space between the keys. The camming surfaces are engage able with one of the grooves to guide the one key into the groove when the segments are forcibly engaged circumferentially around the pipe elements with re-enforcing stiffening rings.
The keys have a wedge-shaped cross-section defined by a pair of opposed key surfaces.
The key surfaces are angularly orientated with respect to a plane passing through the segments. The key surfaces have an orientation angle between 100 and about 300 relatively to the plane. An orientation angle of about 20 relatively to the plane is advantageous.
The first and second camming surfaces are angularly oriented with respect to the key surfaces of the one key. The first and second camming surfaces have an orientation angle between about 20 and about 8 relatively to the key surfaces of the one key.
The first and second camming surfaces can comprise curved surfaces positioned on the one key. The first and second camming surfaces have a concaved curvature or a convex curvature. The first and second camming surfaces each comprise a first portion offset from the key surface on the one key, and.a second surface portion having a concave curvature.
Alternately, the first and second camming surfaces each comprise a first surface portion offset from the key surface on the one key and a second surface portion angularly orientated with respect to the first surface portion.
In one embodiment, a re-enforcing stiffening ring is added to the outside of a pipe element.

3 The re-enforcing stiffening rings have tapered grooves in the face where the two stiffening rings meet end to end. The angles of the tapered grooves match that of the angles on the alignment ring.
In another embodiment, a tapered alignment ring will fully or partially fill the grooves on the face of the re-enforcing stiffening rings. The tapered alignment ring will significantly improve alignment of the two pipe elements joined end to end and will improve the seating of the coupling segment keys with the circumferential grooves on the re-enforcing stiffening rings. The alignment ring has tapered ends, top and bottom with angles between 8 and 45 . The alignment ring can be a complete ring or partial ring.
In a third embodiment, the coupling segments have a minimum of one re-enforced platform located on the outside of the coupling segments located between the stiffening ribs and to be no less than 2.5 inches in length and angled between 30 and 450 at both ends. The re-enforced platform is raised above the outside diameter of the coupling to double the thickness of the coupling segment. A hole is added to the center of the platform at a 90 angle to the surface of the platform and threaded to accommodate sensors such as pressure.
SUMMARY OF THE DRAWINGS
FIG. 1 is a partial view of a coupling system in end to end configuration which includes two of the embodiments of the invention.
FIG. 1A is an enlarged scale cut away side view of the tapered alignment ring which is one of the key embodiments of the invention.
FIG. 2 is an exploded view of the coupling shown in FIG. 1 FIG. 3 is a front view of one coupling segment with a cut away view of the re-enforced platform with threaded hole.
FIG. 3A is a cut away side view of a coupling segment illustrating the re-enforced platiornn with threaded hole.
FIG. 4 is a partial sectional view illustrating a coupling segment.
FIG. 4A is a view taken from circle 4A in FIG. 4 showing a portion of the coupling segment on an enlarged scale.
FIG. 5 is a partial sectional view illustrating a coupling segment.
FIG. 5A is a view taken from circle 5A in FIG. 5 showing a portion of the coupling segment on an enlarged scale.
FIG. 6 is a partial sectional view illustrating a coupling segment.

4 FIG. 6A is a view taken from circle 6A in FIG. 6 showing a portion of the coupling segment on an enlarged scale.
FIG. 7 is a partial sectional view illustrating a coupling segment.
FIG. 7A is a view taken from circle 7A in FIG. 7 showing a portion of the coupling segment on an enlarged scale.
FIG. 8 is a partial sectional view illustrating a coupling segment.
FIG. 8A is a view taken from circle 8A in FIG. 8 showing a portion of the coupling segment on an enlarged scale.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the top half of a pair of pipe elements 1 and 2 joined in end-to-end relation using mechanical coupling segment 4. A pair of re-enforcing stiffening rings 6 and 7 is positioned over the pipe elements with circumferential grooves 8 and 9.
Tapered grooves and 11 are positioned on the inside face of the re-enforcing stiffening rings 6 and 7. A
tapered alignment ring 12 and 0 rings 13 and 14 fill the tapered grooves 10 and lion the re-enforcing stiffening rings 6 and 7. The re-enforced stiffening rings 6 and 7 surround the pipe elements 1 and 2 and serve to add strength to the joint against stresses imposed by bending, pressure and compression due to thermal expansion. The alignment ring ensures near perfect alignment between the two pipe elements 1 and 2 at the ends.
Perfect or near perfect alignment will eliminate or significantly reduce leading edge wear or downstream erosion due to misalignment issues. The alignment ring 12 will maintain improved alignment even in the event of the fasteners 26 loosening slightly.
Each coupling segment 3 and 4 has a pair of keys 15 and 16 and a pair of stiffening ribs 17 and 18. The keys 15 and 16 extend circumferentially around the segments and project radially inwardly toward the re-enforced stiffening rings 6 and 7. The ribs extend circumferentially around the segments and project radially outwardly away from the re-enforced stiffening rings. The keys 15 and 16 are in spaced apart relation with a space there between 19. The ribs 17 and 18 are also in spaced apart relation 20;
each rib is aligned with a respective key. It is advantageous to align the ribs with the keys to effectively strengthen and stiffen the segments 3 and 4 close to where the loads are applied by the pipes to the coupling thereby maintaining maximum key engagement with the groove.
Circumferential grooves 8 and 9 are positioned in the re-enforced stiffening rings 6 and 7, the grooves being engaged by the keys 15 and 16 of the coupling segment. It is advantageous to position the grooves in the rings rather than in the pipe segments to avoid thinning and thereby weakening the pipe wall. Preferably, the keys have a wedge-shaped cross section and the grooves have a complementary shape to the keys.
Engagement of the keys within the grooves prevents thrust loads from separating the pipe elements when they are under pressure. Preferably, the keys and grooves are sized so that the keys fill

5 the grooves when the bolt pads 25 and 26 in FIG. 2 at each end of the segments are in pad to pad engagement. Designing the coupling for pad-to-pad engagement, the joint is easy to inspect visually for compliance with the relevant specifications and the need to specify bolt torques is eliminated. The key surfaces 35 and 36 are of the keys 15 and 16 are oriented at an angles 39 and 40 which is between 100 and 30 to the plane 38, with an orientation angle of about 200 being. advantageous. The side surfaces of the circumferential grooves 8 and 9 on the re-enforced stiffening rings 6 and 7 are matched to the angles on the coupling keys 15 and 16. Preferably, the angle is about 20 .
This range of angles for the side surfaces of the keys and the grooves is found effective at preventing ejection of the re-enforcing stiffening rings from the coupling under the pressures experienced during operation. The angular range of the key surfaces is also advantageous for maintaining the joints in the face of compression loads caused when the pipes heat up and expand between anchor points.
FIG. 1A shows an expanded view of the alignment ring 12 with tapered ends, top and bottom 21, 22, 23 and 24. Angles 21, 22, 23 and 24 may range between 8 and 45 .
FIG. 2 shows coupling 5 is formed of a plurality of segments, in this example, two segments 3 and 4. The segments are joined end-to-end by bolt pads 25 and 26 positioned at each end of each segment. The bolt pads are joined by fasteners 27, in this example, bolts 28 and nuts 29. Together, the bolt pads 25 and 26 and fasteners 27comprise a means for attaching the segments end-to-end. Each coupling segment consists of a pair of keys 15 and 16 which are spaced apart with a space in between 19. The keys 15 and 16 extend circumferentially around the segments and project radially inwardly.
Each coupling segment 3 and 4 have a pair of stiffening ribs 17 and 18. The ribs extend circumferentially around the segments and project radially outward away from the pipe elements #
with re-enforced stiffening rings #. A pair of re-enforced platforms with threaded holes is located on each coupling segment 30. As shown in FIG. 2 each of the keys has a pair of oppositely disposed camming surfaces 34 and 35 positioned at each end of the segments.
The camming surfaces extend circumferentially over a portion of the keys. The portion occupied by a single camming surface may include between 5% and 10% of the total arc length of the key. As shown in FIG. 2, one of the camming surfaces 34 faces outwardly away from the space 19 and the other surface 35 faces inwardly toward the space.
An advantage is secured by having oppositely disposed camming surfaces 34 and 35 at the ends of keys 15 and 16. Namely, the camming surfaces serve as guides who allow the pipe ends relatively wide latitude of misalignment and separation at the start of assemble but still enable the coupling segments 3 and 4 to be readily engaged with the pipe ends.
Separation distances of up to 3/8 inches between the pipe ends are tolerable, the camming surfaces acting as guides to catch the grooves as they are brought into engagement and force the pipe elements to assume their desired relative position by forcible interaction between the camming surfaces and the grooves. The alignment ring maintains alignment of the pipe ends while the camming surfaces engage the grooves, and ultimately the coupling keys and grooves. The alignment ring aligns the pipe ends during installation and during its normal operation. The interaction of the alignment ring

6 and the tightening of the couplings segments around the pipe elements results in axially, angularly and laterally aligned pipe ends. Ultimately, a smooth continuous inner surface is achieved which eliminates or significantly reduces leading edge wear or downstream erosion.
FIG. 3 shows a coupling segment 3 with a cut away section 33 to show the re-enforced platform 30 with threaded hole. The thickness of the re-enforced platform 30 is twice that of the standard coupling thickness. The re-enforced platform 30 is to be no less than 2.5 inches in length circumferentially. The width is that of the space between the stiffening ribs 17 and 18. There will be a minimum of one re-enforced platform per coupling segment.
The edges of the re-enforced platform are angled 31 between 25 and 45 inwardly.
FIG. 3A shows a cutaway side view of a coupling segment. A thread hole at a 900 angle 31 to the outer surface of the re-enforced platform is created to accommodate temperature and pressure sensors. A pressure sensor could indicate if the coupling system is leaking past the alignment ring 12 with 0 rings 13 and 14.
Each camming surface is defined by a thinning of the key on which it is positioned. The thinning may be effected in various ways as depicted in FIGS. 4 to 7. As shown in FIGS. 4 and 4A, the camming surfaces are created on opposite sides of the keys 15 and 16 by curved surfaces 39A and 40A having a radii R1 and R2, which may or may not be the same. Surfaces 39A and 40A are concave relative to the surfaces of the keys 15 and 16.
Alternately, FIGS. 5 and 5A, camming surfaces 39B and 40B are convexly curved surfaces having respective radii R3 and R4, which again, may or may not be the same.
FIGS. 6 and 6A illustrates the camming surfaces 39 c and 40 c are substantially flat surfaces which are angularly oriented with respect to the key surface on which they are positioned. The camming surfaces 39 c and 40 c have orientation angles 41 and between about 20 and about 80 relatively to the respective key surfaces 36 and 37 on which each camming surface is positioned.
FIGS. 7 and 7A illustrates camming surface 39 and 40 is formed of two surface portions.
Camming surface 39 is formed of a flat surface portion 39 d and a concavely curved surface portion 39 e. Similarly, camming surface 40 is formed of a flat surface portion 40 d and a concavely curved surface portion 40 e. The flat surface portion 39 d and 40 d are substantially parallel to the reference plane 38 and offset from the key surfaces 36 and 37.
The curved surface portion 39 e and 40 e have respective radii R5 and R6. The curved surface portions 39 e and 40 e provide a smooth transition between the flat surface portions 39 d and 42 d and the surfaces 36 and 37 of the keys 15 and 16.
FIG. 8 AND 8A, each camming surface 39 and 40 is formed of two surface portions.
Cam ming surface 39 is formed from a flat surface portion 39 f and an angularly oriented surface portion 39 g. similarly, camming surface 40 is formed from a flat surface portion 40 f and an angularly oriented surface portion 40 g. the flat surface portions 39 f and 40 f are substantially parallel to the reference plane 38 and offset from the key surfaces 36 and 37.
The angularly oriented surface portions 39 g and 40 g have orientation angles 43 and 44

7 measured relatively to the surfaces 36 and 37 of the keys 15 and 16.
Orientation angles between about 2 to about 150 are feasible. The angularly oriented surface portions 39 g and 40 g provide a smooth transition between the flat, offset surface portions 39 f and 40 f and the surfaces of the keys 36 and 37.
One camming surface on a particular key need not be the same length, have the same offset, orientation angle or have the same curvature as its opposite camming surface on the same key. Additionally, the Gemming surfaces at opposite ends of a segment need not be the same as one another.

Claims

Claims 1. A coupling system with re-enforced platforms, keys and sniffing ribs for connecting two pipe elements together end-to-end, each of said pipe elements having re-enforcing stiffening ring with circumferential groove proximate to an end thereof and a tapered groove on the inside face to accommodate a tapered alignment ring, said coupling system comprising:
a plurality of segments positionable end-to-end circumferentially around said pipe elements with re-enforcing stiffening rings on the outside of the pipe elements, each of said coupling segments having a pair of keys projecting radially inwardly toward said pipe elements with re-enforcing stiffening ring and a pair of stiffening ribs projecting radially outwardly away therefrom, said ribs being positioned in spaced apart relation to one another, each said key for engagement with said circumferential groove of the re-enforcing stiffening ring on one of said pipe elements, said keys being positioned in spaced apart relation from one another and defining a space there between, at least one of said keys on one of said segments having first and second camming surfaces oppositely disposed and positioned adjacent to one end of said coupling segment, said first camming surface facing away from said space between said keys, said second camming surface facing toward said space between said keys, said first and second camming surfaces each comprising a first surface portion oriented parallel to a single plane passing through said coupling segments and offset from said key surface on said one key, and a second surface portion oriented transversely to said plane, said camming surfaces being engageable with one said grooves to guide said one key into said groove when said coupling segments are forcibly engaged circumferentially around said pipe elements with re-enforcing stiffening rings.
2. The coupling system according to claim 1, wherein the re-enforcing stiffening rings have circumferential grooves with angles that align with that of said keys on the coupling segments.
3. The coupling system according to claim 1, wherein the re-enforcing stiffening rings has tapered grooves in the face where the two stiffening rings meet end to end.
4. The coupling system according to claim 3, wherein the angles of the tapered grooves match that of the angles on the alignment ring.
5. The coupling system according to claim 3, wherein a tapered alignment ring will fully or partially fill the grooves on the face of the re-enforcing stiffening rings.
6. The coupling system according to claim 5, wherein the tapered alignment ring will significantly improve alignment of the two pipe elements throughout the installation of the coupling, normal operation and movement of multiple sections of connected piping.
7. The coupling system according to claim 6, were alignment includes axial, angular and lateral alignment.
8. The coupling system according to claim 6, wherein the tapered alignment ring will improve the seating of the coupling segment keys with the circumferential grooves on the re-enforcing stiffening rings.
9. The coupling system according to claim 5, wherein the alignment ring has tapered ends, top and bottom with angles between 8° and 45°.
10. The coupling system according to claim 5, wherein the alignment ring can be a complete ring or partial ring.

11. The coupling segments according to claim 1, have a minimum of one re-enforced platform located on the outside of the coupling segments located between the stiffening ribs and to be no less than 2.5 inches in length and angled inwardly between 30° and 45°
at both ends.
12. The coupling segment according to claim 11, wherein the re-enforced platform is raised above the outside diameter of the coupling between the two stiffening ribs to double the thickness.
13. The coupling segments according to claim 11, wherein a hole is added to the center of the re-enforced platform at a 900angle to the surface of the platform and threaded.
14. The coupling system according to claim 1, wherein each of said ribs is substantially aligned with one of said keys.
15. The coupling system according to claim 1, wherein said keys have a wedge-shaped cross-section defined by a pair of oppositely disposed key surfaces, said key surfaces being angularly oriented with respect to said plane passing through said segments.
16. The coupling system according to claim 15, wherein said key surfaces each have an orientation angle between about 10° and about 30° relatively to said plane.
17. The coupling system according to claim 15, wherein said key surfaces each have an orientation angle of about 20° relatively to said plane.
18. The coupling system according to claim 1, wherein said second surface portion is angularly oriented with respect to said first surface portion.
19. The coupling system according to claim 18, wherein said second surface portion is angularly oriented with respect to said key surfaces of said at least one key.
20. The coupling system according to claim 19, wherein said second surface portion has an orientation angle between about 2° and about 8° relatively to said key surfaces of said one key.
21. The coupling system according to claim 1, wherein said second surface portion has a concave curvature.
22. A coupling system with re-enforced platforms, keys and stiffening ribs for connecting two pipe elements together end-to-end, each of said pipe elements having re-enforcing stiffening ring with circumferential groove proximate to an end thereof and a tapered groove on the inside face to accommodate a tapered alignment ring, said coupling system comprising:
a pair of segments positionable end-to-end circumferentially around said pipe elements with re-enforcing stiffening rings on the outside of the pipe elements, each of said coupling segments having a pair of keys projecting radially inwardly toward said pipe elements with re-enforcing stiffening ring and a pair of stiffening ribs projecting radially outwardly away therefrom, said ribs being positioned in spaced apart relation to one another, each said key for engagement with said circumferential groove of the re-enforcing stiffening ring on one of said pipe elements, said pair of keys on each said segment being positioned in spaced apart relation from one another and defining a space there between, each of said keys on each of said segments having first camming surfaces positioned at opposite ends of said keys and facing away from said space between said keys, each of said keys on each of said segments having second camming surfaces positioned at opposite ends of said keys and facing toward said space between said keys, said first camming surface comprising a first surface portion being substantially flat and parallel to a single plane passing through said segments, said first surface portion being offset from said key surface facing away from said space between said keys; a second surface portion oriented transversely to said plane, said second surface portion being positioned between said first surface portion and said key surface facing away from said space; and wherein said second camming surfaces comprises: a first surface portion being substantially flat and parallel to said plane, said first surface portion of said second camming surface being offset from said key surface facing toward said space between said keys; and a second surface portion being oriented transversely to said plane, said second surface portion of said second camming surface being positioned between said first surface portion of said second camming surface and said key surface facing toward said space, said camming surfaces being engageable with one of said grooves to guide said keys into said grooves when said segments are forcibly engaged circumferentially around said pipe elements with re-enforcing stiffening rings 23 The coupling system according to claim 22, wherein the re-enforcing stiffening rings have circumferential grooves with angles that align with that of said keys on the coupling segments.
24 The coupling system according to claim 22, wherein the re-enforcing stiffening rings has tapered grooves in the face where the two stiffening rings meet end to end.
25. The coupling system according to claim 24, wherein the angles of the tapered grooves match that of the angles on the alignment ring.
26. The coupling system according to claim 24, wherein a tapered alignment ring will fully or partially fill the grooves on the face of the re-enforcing stiffening rings 27 The coupling system according to claim 26, wherein the tapered alignment ring will significantly improve alignment of the two pipe elements throughout the installation of the coupling, normal operation and movement of multiple sections of connected piping.
28.The coupling system according to claim 27, were alignment includes axial, angular and lateral alignment 29. The coupling system according to claim 27, wherein the tapered alignment ring will improve the seating of the coupling segment keys with the circumferential grooves on the re-enforced stiffening rings.
30 The coupling system according to claim 26, wherein the alignment ring has tapered ends, top and bottom with angles between 8° and 45°.
31. The coupling system according to claim 26, wherein the alignment ring can be a complete ring or partial ring.
32. The coupling segments according to claim 22, have a minimum of one re-enforced platform located on the outside of the coupling segments located between the stiffening ribs and to be no less than 2.5 inches in length and angled between 30°
and 45° at both ends.
33. The coupling segment according to claim 32, wherein the re-enforced platform is raised above the outside diameter of the coupling between the two stiffening ribs to double the thickness.
34 The coupling segments according to claim 32, wherein a hole is added to the center of the platform at a 90° angle to the surface of the platform and threaded.
35. The coupling system according to claim 22, wherein each of said ribs is substantially aligned with one of said keys.
36 The coupling system according to claim 22, wherein each of said keys has a wedge-shaped cross-section defined by a pair of oppositely disposed key surfaces, said key surfaces being angularly oriented with respect to a plane passing through said segments, one of said key surfaces facing away from said space between said keys, the other of said key surfaces facing toward said space between said keys.

37. The coupling system according to claim 36, wherein said key surfaces each have an orientation angle between about 10° and about 30° relatively to said plane.
38. The coupling system according to claim 36, wherein said key surfaces each have an orientation angle of about 20° relatively to said plane.
39. The coupling system according to claim 36, wherein said second surface portion of said first camming surface has an orientation angle between about 2°
and about 8°
relatively to said key surface facing away from said space between said keys and said second surface portion of said second camming surface has an orientation angle between about 2° and about 8° relatively to said key surface facing toward said space between said keys.
40. The coupling system according to claim 22, wherein said second camming surface comprises a curved surface.
41. The coupling system according to claim 40, wherein said second camming surface has a concave curvature.
42. The coupling system according to claim 40, wherein said second camming surface has a convex curvature.
43. The coupling system according to claim 22, wherein said second surface portion has a concave curvature; and wherein said second surface portion having a concave curvature.
45. The coupling system according to claim 22, wherein said second surface portion has an angular orientation; and wherein said second surface portion has an angular orientation.