(19)
(11)EP 2 759 354 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
14.10.2015 Bulletin 2015/42

(21)Application number: 14158515.8

(22)Date of filing:  30.11.2011
(51)International Patent Classification (IPC): 
B21D 17/04(2006.01)
B21D 22/16(2006.01)
B21D 15/06(2006.01)

(54)

Method and apparatus for manufacturing a pipe element having shoulder, groove and bead

Vorrichtung und Verfahren zur Herstellung ein Rohrelement mit Schulter, Rinne und Wulst

Appareil et procédé pour la fabrication d'un élément de tuyau doté d'épaulement, rainure et talon


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 02.12.2010 US 418967 P
02.09.2011 US 201161530771 P

(43)Date of publication of application:
30.07.2014 Bulletin 2014/31

(62)Application number of the earlier application in accordance with Art. 76 EPC:
11844300.1 / 2643625

(73)Proprietor: Victaulic Company
Easton, PA 18040 (US)

(72)Inventors:
  • Novitsky, Michael, R.
    Easton, PA Pennsylvania 18080 (US)
  • Haas, Earl
    Franklin, IN Indiana 46131 (US)
  • Wilk, Charles, E., Jr.
    Slatington, PA Pennsylvania 18080 (US)
  • Madara, Scott, D.
    Nazareth, PA Pennsylvania 18064 (US)
  • Cuvo, Anthony, J.
    Coopersburg, PA Pennsylvania 18036 (US)
  • Dole, Douglas, R.
    Whitehouse Station, NJ New Jersey 08889 (US)

(74)Representative: De Anna, Pier Luigi 
DeAnna-Patent Schubertstraße 10
80336 München
80336 München (DE)


(56)References cited: : 
FR-A1- 2 786 417
US-A1- 2004 255 632
JP-A- H09 201 625
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Field of the Invention



    [0001] This invention relates to a spin forming machine and methods of use thereof for forming circumferential shoulder, groove and bead in pipe elements to be joined together by mechanical couplings.

    Background



    [0002] Various challenges are encountered when designing pipe elements to be joined by mechanical pipe couplings. Such couplings comprise two or more coupling segments joined in end to end relation by threaded fasteners. The segments surround a central space which receives the pipe elements. Each segment has a pair of arcuate projections known as "keys" which engage the outer surfaces of the pipe elements. The keys are often received in circumferential grooves in the pipe elements which provide a positive mechanical engagement against bending and axial loads applied to the joint. Each segment also defines a channel between its pair of arcuate projections which receives a ring-shaped gasket. The gasket is typically compressed between the segments and the pipe elements to effect a fluid tight joint.

    [0003] Circumferential grooves are advantageously formed by cold working the sidewall of the pipe element because, unlike cut grooves, material is not removed from the pipe sidewall and thus thinner walled pipe elements may be grooved by the cold working process. It is advantageous to use thinner walled pipe elements for weight and cost savings in high pressure and /or high load applications. However, prior art cold working methods and pipe designs do not produce coupling and pipe element engagement features adequate for high loads and pressures sustainable by comparable cut groove systems used on thicker walled pipe elements.
    JP-H-09201625 discloses a spin forming machine for forming circumferential shoulder, groove and bead in a pipe element according to the preamble of claim 1.
    There are clear advantages to be had through improvements to the design and manufacture of thin walled grooved pipe elements by cold working which will allow thin walled grooved pipe elements to be joined by mechanical couplings and used in high pressure/high load applications.

    Summary



    [0004] The invention concerns a spin forming machine for forming circumferential shoulder, groove and bead in a pipe element according to claim 1. The machine includes a die formed in four sections mounted in bearings and slidably moveable toward and away from one another using respective actuators, a spin forming tool mounted in a housing with a fixed axis of rotation and mounted on a carriage which moves along guide rods toward and away from the die, an actuator effecting the motion of the carriage and hence effecting the motion of the spin forming tool toward and away from the die, a housing driven in rotation about axis relatively to carriage on bearings by an electric motor mounted on the carriage and the axis of rotation of housing is substantially parallel to the longitudinal axis of the opening defined when the die sections are brought together. The invention also relates to a method of forming a circumferential bead and groove in a pipe element by using the machine of the invention, as defined in claim 7.
    The invention also encompasses a spin forming method for forming a circumferential shoulder, groove and bead in a pipe element by using the machine of the invention, as defined in claim 9. The spin forming method comprises: capturing an end of the pipe element in a die; inserting a tool within the pipe element; revolving the tool in an orbit about a longitudinal axis of the pipe element; increasing the diameter of the orbit while revolving the tool so as to force the tool against an inner surface of the pipe element; conforming the pipe element to the die so as to form a circumferential shoulder therein, the shoulder having a larger outer diameter than the outer diameter of the remainder of the pipe element; conforming the pipe element to the die so as to form a circumferential bead therein, the bead having an apex with a larger outer diameter than the outer diameter of the remainder of the pipe element; forcing the tool against the inner surface of the pipe element while revolving the tool in the orbit of increasing diameter causing a portion of the tube between the shoulder and the bead to move radially inwardly away from the die thereby forming the groove, the groove having a smaller outer diameter than the outer diameter of the remainder of the pipe element.

    Brief Description of the Drawings



    [0005] 

    Figures 1 and 1 A are longitudinal sectional views of example pipe elements;

    Figure 2 is an isometric view of a valve including an example pipe element;

    Figure 3 is an exploded isometric view of a combination of pipe elements and a pipe coupling;

    Figures 3A and 3B are elevational views of pipe coupling;

    Figures 4-6 are longitudinal sectional views of a combination of pipe elements and a pipe coupling; [0026] Figure 7 is a schematic diagram of an example spin forming machine according to the invention for manufacturing pipe elements using a spin forming method according to the invention;

    Figure 8 is a schematic end view of the spin forming machine shown in Figure 7; and

    Figures 9-11 are longitudinal sectional views illustrating an example method of spin forming pipe elements.


    Detailed Description



    [0006] The invention concerns methods and devices for cold working pipe elements to receive couplings and form a fluid tight joint. Throughout this document the term "pipe element" means any tubular structure, including, for example, pipe stock 10 as shown in Figure 1, as well as the tubular portion 12 of a fluid handling or control component such as the valve 14 shown in Figure 2. Other components, such as pumps and strainers, as well as fittings such as tees, elbows, bends and reducers are also included as having or comprising "pipe elements" as defined herein.

    [0007] As shown in Figure 1, pipe element 10 has an outer diameter 16 which passes through a point on a longitudinal axis 18 at the pipe element's center of curvature. At least one end 20 of pipe element 10 is configured to receive a key of a mechanical coupling (not shown), the configuration comprising a shoulder 22 positioned at the end 20, a groove 24 positioned adjacent to the shoulder 22, and a bead 26 positioned contiguous with the groove 24.

    [0008] As illustrated in detail in Figure 1, shoulder 22 extends circumferentially around the pipe element and has an outwardly facing surface 28. Surface 28 has an outer diameter 30 that is greater than the outer diameter 16 of the pipe element 10 excluding the shoulder. Shoulder 30 also has an outwardly facing curved surface 32. Curved surface 32 also extends circumferentially around the pipe element and has a center of curvature on an axis 34 oriented perpendicular to the longitudinal axis 18 of the pipe element 10. In Figure 1, axis 34 is shown perpendicular to the viewing plane and is therefore seen end on.

    [0009] Groove 24 is defined by a first side surface 36 which is positioned contiguous with the curved surface 32 of the shoulder 30. Side surface 36 may be oriented angularly. The orientation angle 41 may range from about 80° to about 85° with respect to the longitudinal axis 18. In another embodiment, the side surface 36 maybe oriented substantially perpendicularly to longitudinal axis 18. "Substantially perpendicularly" as used herein refers to an angular orientation which may not be exactly perpendicular, but is established as close as practicable in view of manufacturing practices and tolerances. Perpendicular orientation of the first side surface 36 stiffens the pipe element radially and helps it maintain its roundness.

    [0010] A second side surface 38 further defines the groove 24. Second side surface 38 is positioned in spaced apart relation to the first side surface 36 and is oriented angularly with respect to the longitudinal axis 18. Side surface 38 may have an orientation angle 40 from about 40° to about 70° or about 45° to about 65°. In the particular embodiment shown in Figure 1, orientation angle 40 is about 55° which is considered advantageous when the groove receives keys of a mechanical coupling as shown in Figures 3-6.

    [0011] A floor surface 42 extends between the first side surface 36 and the second side surface 38 of groove 24. In the example embodiment shown, the floor surface 42 is substantially parallel to the longitudinal axis 18 and has an outer diameter 44 which is less than the outer diameter 16 of the pipe element excluding the groove. The groove 24 also has an inner diameter 17 which, in the embodiment shown in Figure 1, is approximately equal to the inner diameter 19 of the pipe element 10.

    [0012] Bead 26 is positioned contiguous with the second side surface 38 of the groove 24 and also extends circumferentially around the pipe element. The bead 26 projects outwardly away from axis 18 and has an apex 46 with an outer diameter 48 greater than the outer diameter 16 of the pipe element excluding the bead. In the example embodiment shown in Figure 1, the diameter 48 of the apex 46 is less than the outer diameter 30 of shoulder 22. Bead 26 increases the radial stiffness of the pipe element and thereby helps maintain its roundness.

    [0013] As shown in Figure 1 A, a beadless pipe element embodiment 10a is also feasible. Similar to the embodiment 10 shown in Figure 1, for the embodiment 10a in Figure 1 A the floor surface 42 is substantially parallel to the longitudinal axis 18 and has an outer diameter 44 which is less than the outer diameter 16 of the pipe element excluding the groove. The groove 24 also has an inner diameter 17 which is approximately equal to the inner diameter 19 of the pipe element 10a.

    [0014] For pipe stock, the configuration of the end of the pipe element 10 (shoulder 22, groove 24 and bead 26) is the same at both ends (not shown for clarity), but other configurations are also feasible wherein the ends may be dissimilar. Furthermore, the pipe elements 50 at opposite ends of valve 14 also have the above-described end configurations which allow the valve, or any other fluid control component or fitting, to be joined to other pipe elements using mechanical couplings, examples of which are shown in Figures 3, 3A and 3B. Alternately, valves and other fluid control components and fittings may also have dissimilar end configurations.

    [0015] In one embodiment, illustrated in Figure 3, mechanical coupling 52 comprises two or more segments 54 attached to one another in end to end relation, in this example by threaded fasteners 56. The segments 54 surround a central space 58 which receives the pipe elements 10 to join them in a fluid tight joint. An elastomeric gasket 60 is captured between the segments 54 and has inwardly facing sealing surfaces 62 which engage the outwardly facing surfaces 28 of shoulders 24 to ensure fluid tightness. Each segment has a pair of arcuate surfaces or keys 64 which project inwardly toward the central space and are received within the grooves 24 of the pipe elements 10.

    [0016] In another embodiment, shown in Figure 3A, the coupling 53 comprises a single segment formed of a unitary body 55 having ends 57 and 59 in spaced apart, facing relation. Bolt pads 61 extend from the ends 57 and 59 and a fastener 63 extends between the bolt pads for drawing them together upon tightening of the fastener. The unitary body surrounds a central space 65 which receives the pipe elements to form a joint. Keys 67 in spaced relation on either side of the coupling 53 extend circumferentially along the unitary body 55 and project radially inwardly. A gasket 60 similar to that as described above is positioned between the keys. Tightening of the fastener 63 draws the keys 67 into engagement with grooves in the pipe elements and compresses the gasket 60 between the unitary body 55 and the pipe elements.

    [0017] Figure 3B shows another coupling embodiment 69, formed of two segments 71 and 73 joined at one end by a hinge 75. The opposite ends 77 and 79 of the segments are in spaced apart facing relation and connected by a fastener 81. Segments 71 and 73 also have circumferential keys 83 in spaced relation and a gasket 60 is positioned between them. The segments surround a central space 65 which receives the pipe elements to form a joint. Tightening of the fastener 81 draws the keys 83 into engagement with grooves in the pipe elements and compresses the gasket 60 between the segments and the pipe elements.

    [0018] A joint may be formed between two pipe elements 10 by first disassembling the coupling 52 (see Figure 3) and slipping the gasket 60 over an end of one of the pipe elements. The end of the other pipe element is then aligned in proximity with the end of the first pipe element, and the gasket is positioned so as to bridge the small gap between the two pipe element ends, with the sealing surfaces 62 of the gasket engaging respective outer surfaces 28 of the shoulders 24 of each pipe element. Next the coupling segments 54 are positioned surrounding the gasket 60 and the ends of the pipe elements with the keys 64 aligned with respective grooves 24 in each pipe element. Fasteners 56 are then applied and tightened so as to draw the segments toward one another, engage the keys 64 within respective grooves 24 and compress the gasket 60 against the pipe elements so as to form a fluid tight joint.

    [0019] In an alternate embodiment, Figures 4-6 show in detail the engagement of the pipe elements 10 with an installation ready type coupling 52 wherein the segments 54 are pre-assembled and held in spaced relation from one another by fasteners 56, the segments being supported on the gasket 60. The segments are sufficiently far apart that the pipe elements 10 may be inserted into the central space 58 without disassembling the coupling as shown in Figures 4 and 5. Note that the outwardly facing surfaces 28 of shoulders 22 engage the sealing surfaces 62 of the gasket 60 and the keys 64 align with the grooves 24 in each of the pipe elements. As shown in Figure 6, the fasteners 56 (see also Figure 1) joining the segments 54 to one another are tightened, drawing the segments toward one another. This compresses the gasket 60 against the pipe elements to effect a seal and forces the keys 64 into the grooves 24 to effect a positive mechanical connection between the coupling and the pipe elements 10 to effect the joint. In one embodiment, shown in detail in Figure 6, the keys 64 have a cross sectional shape that is compatible with the grooves, and the keys are dimensioned such that a first lateral key surface 66 engages the groove first side surface 36, and a second lateral key surface 68 engages the angularly oriented second side surface 38 of the groove. It is advantageous that the surfaces 68 and 38 have complementary orientation angles to maximize surface to surface contact. Orientation angles for lateral key surface 68 measured with respect to the pipe element longitudinal axis 18 (see also Figure 1) from about 40° to about 70°, or from about 45° to about 65°, or about 55° are contemplated. It is also advantageous that surfaces 66 and 36 have complementary orientation angles. Orientation angles for lateral key surface 66 measured with respect to the pipe element longitudinal axis 18 (see also Figure 1) from about 80° to about 85° are contemplated.

    [0020] In general for this embodiment there will be a gap 70 between the groove floor surface 42 and a radially facing surface 72 of the key 64. This is due to tolerance variations in both the pipe element and the coupling. Some gap between surfaces 42 and 72 is advantageous to ensure that the keys engage the groove with a wedging action that provides rigidity to the joint and maintains the pipe elements in spaced relation to one another under axial compression and tension loads. Formation of the joint using coupling embodiments 53 and 69 shown in Figures 3A and 3B proceeds similarly as described above for the installation ready embodiment. Other embodiments are also feasible, for example, wherein only the vertical key surface 66 is in contact with the groove first side surface 36, or only the angularly oriented key surface 68 is in contact with the second side surface 38 of the groove 24. It is also possible that the coupling segments float on the gasket 60, wherein none of the key surfaces are in contact with the groove surfaces, at least initially until the joint is subjected to load.

    Spin Forming



    [0021] Spin forming uses a fixed outer die and a roller tool which revolves in an orbit within the die. The pipe element is held within the die between it and the tool, and the tool orbits about the pipe's longitudinal axis. The tool's orbit is increased in diameter and the tool is forced against the inner surface of the pipe element. As the tool revolves it forces the end of the pipe element to conform in shape to the shape of the tool and die.

    [0022] Spin forming is advantageous because it eliminates the sensitivity of the process to the pipe element outer diameter tolerance variation. While techniques such as roll forming may be used to cold work the pipe element and produce the desired shoulder-bead-groove shape, it is difficult to establish the shoulder and the groove outer diameters with an acceptable degree of repeatability due to the variation in pipe element outer diameter. However, by using spin forming with its fixed outer die, the dimensional variations of the pipe element outer diameter are not relevant since the outer die reliably establishes the pipe element's outer surface dimensions regardless of the initial diameter of the pipe element.

    [0023] Figures 7 and 8 schematically depict an example spin forming machine 136. As shown in Figure 8, the machine 136 includes a die 138 formed in four sections 140, 142, 144 and 146. The die sections are mounted in bearings (not shown) and are slidably moveable toward and away from one another using respective actuators 148, 150, 152 and 154. In this example there are four die sections configured in offset pairs (140 and 142, 144 and 146) but dies having only two sections are also feasible although this possibility is not covered by the invention as claimed. As shown in Figure 7, a spin forming tool 156 is mounted in a housing 158. Housing 158 has a fixed axis of rotation 160 and is mounted on a carriage 162 which moves along guide rods 164 toward and away from the die 138. An actuator 166 effects motion of the carriage 162 and hence motion of the spin forming tool 156 toward and away from the die. Housing 158 is driven in rotation about axis 160 relatively to carriage 162 on bearings 168 by an electric motor 170 also mounted on the carriage. The axis of rotation 160 of housing 158 is substantially parallel to the longitudinal axis 161 of the opening defined when the die sections 140, 142, 144 and 146 are brought together. However, the spin forming tool 156 may be moved relatively to the housing 158 in a direction so as to offset its longitudinal axis 172 from the housing axis of rotation 160. Offset motion of the spin forming tool 156 is via an actuator 174 mounted on the housing 158. A spring 176 provides restoring force which moves the spin forming tool's longitudinal axis 172 back into coaxial alignment with the housing axis of rotation 160 when force of the actuator 174 is relieved.

    [0024] As shown in Figure 9, the die sections (140 being shown) have an inner surface 178 shaped to produce a desired final shape of the outer surface 134a of the pipe element 134 during spin forming. Furthermore, the spin forming tool 156 has an outer surface 180 shaped to cooperate with the inner surfaces 1 78 of the die sections and allow the material of the pipe element 134 to deform and flow so that when, during the spin forming process, the outer surface 180 of the spin forming tool 156 is forced against the inner surface 134b of the pipe element 134, the outer surface 134a of the pipe element 134 takes the desired shape defined by the inner surfaces 178 of die 138.

    [0025] In operation, as illustrated in Figures 8-11, actuators 148 and 150 move respective die sections 140 and 142 away from one another. Similarly, actuators 152 and 154 move respective die sections 144 and 146 away from one another, thereby opening the die 138. The pipe element 134 may then be inserted into the die. As shown in Figure 9, the die 138 is then closed by bringing the respective die sections 140 and 142, 144 and 146 together using their respective actuators to capture the end of the pipe element 134. Next, as shown in Figures 12 and 14, actuator 166 moves carriage 162 toward the die 138. Spin forming tool 156 with its longitudinal axis 172 positioned at this time in coaxial alignment with the axis of rotation 160 of housing 158, and hence also in coaxial alignment with both the longitudinal axis 161 defined by the die 138 and the longitudinal axis 182 of the pipe element 134, is moved toward the die 138. The spin forming tool 156 is inserted within the pipe element 134 captured by the die. Housing 158 is then rotated by motor 1 70 about its axis of rotation 160, and the actuator 174 moves the longitudinal axis 1 72 of the spin forming tool 156 out of coaxial alignment with the longitudinal axis 160 of the housing. This configuration is shown in Figure 10, where the axis 172 of spin forming tool 156 is also offset from the longitudinal axis 182 of pipe element 134. This eccentric configuration causes the spin forming tool 156 to revolve around the longitudinal axis 182 of the pipe element 134 in a circular orbit upon rotation of the housing 158. The diameter of the orbit increases as the actuator 174 continues to move the spin forming tool 156 further off the axis of rotation 160 of the housing 158. Continued motion of the spin forming tool 156 relative to housing 158 while the housing is rotating forces the tool against the inner surface 134b of the pipe element 134. As shown in Figure 11, the spin forming tool 156 travels around the pipe element inner surface in its orbit and cold works the material, forcing the outer surface 134a of the pipe element 134 to substantially conform to the shape of the inner surfaces 178 of the die 138. In this example, the shoulder 22, groove 24 and bead 26 are formed. However, it is also possible to form only a shoulder and the groove, or only the bead and the groove, depending on the shape of the die and the spin forming tool. Note that to mitigate friction between the spin forming tool 156 and the inner surface 134b of the pipe element 134, the spin forming tool is free to rotate about its longitudinal axis 172. Once the desired shoulder-bead-groove shape is achieved upon completion of the spin forming process, rotation of housing 158 is halted, the longitudinal axis 172 of the spin forming tool 156 is moved back into alignment with the housing longitudinal axis 160, and the carriage 162 is move away from the die 138, thereby removing the spin forming tool 156 from within pipe element 134. Die 138 is then opened by moving the die sections 140, 142, 144 and 146 apart, thereby allowing removal of the formed pipe element from the die.

    [0026] It is observed that when spin forming is used to contemporaneously form both the shoulder 22 and bead 26 on opposite sides of the groove 24 as described above, the pipe element material is forced to flow into the area of the pipe element defining the groove such that the groove is formed by the material moving radially inwardly toward the longitudinal axis 182 of the pipe element 134 in the opposite direction to the increasing diameter of the orbit of the spin forming tool 156. The region of the pipe element forming the groove 24 moves away from the die inner surfaces 178 and a gap 184 forms between the groove floor 42 and the inner surfaces 178 of the die 138. The groove floor 42 is smaller in diameter than the die 138 upon completion of the forming process. This motion of the pipe element material contrary to the radially outward motion of the spin forming tool 156 is unexpected, and allows pipe elements 134 to be formed wherein the outer surface 134a of the groove 24 has a diameter 186 less than the diameter 188 of the outer surface of the remainder of the pipe element; i.e., the outer surface 134a of the pipe element exclusive of the groove 24. It was previously thought that such a configuration was possible only with roller forming of the pipe element between two rotating rollers, but spin forming according to the invention allows this configuration to be achieved while maintaining precise and repeatable outer dimensions of the pipe element due to the effect of the fixed die capturing the pipe element. This is unexpected because it was thought that spin forming could only expand a pipe element; i.e., any part of a pipe element deformed by spin forming must have a diameter larger than the original dimension. Therefore, according to the common wisdom, it would not be possible, in a spin forming process, to start with a pipe element having a first outer diameter and end up with a portion of the pipe element having a second outer diameter smaller than the first outer diameter, but applicants have achieved this using spin forming in the method according to their invention.

    [0027] The pipe element configurations comprising the shoulder, groove and bead, and the methods and apparatus for creating the configurations as shown and described herein allow thin walled pipe elements to be joined by mechanical couplings and used in high pressure/high load applications previously thought unsuited for thin walled pipe elements and grooved mechanical couplings. Various additional advantages over prior art pipe elements are also realized. For example, it is known that the outer diameter 186 of the groove floor 42 is an important dimensional parameter for compatibility between couplings and pipe elements in view of pipe element diameter manufacturing tolerances. The spin forming method disclosed herein permits this parameter to be controlled so that grooves can be formed that are compatible with couplings at both the maximum and minimum pipe diameter tolerances. Furthermore, the combination of the enlarged shoulder diameter 190 (shoulder 22 outwardly facing surface larger than the pipe element outer diameter) and the reduced groove floor diameter (groove floor 42 outer diameter less than the pipe element outer diameter) allows lighter weight couplings to be used without a performance penalty. It is also easier to design the couplings due to the tighter tolerances to which the groove and shoulder dimensions can be held. Practically, this translates into lower cost couplings at lower weight, and stronger joints withstanding higher internal pressures. Gasket design is also simplified because of the tighter tolerances afforded, and it is easier to manage the size of the gap which forms between coupling segments through which the gasket can be extruded and blow-out under high pressures. Manufacturing advantages are also secured as there is less thinning of the pipe element and less cold working required which means lower residual stresses, higher remaining elongations, and stronger pipe elements. The addition of the bead 26 permits a more rigid joint and allows the key to fill the groove and employ a wedging action to advantage. The wedging action holds the pipe elements within the coupling at a constant distance even when under axial compression, due, for example to thermal loads or a vertical pipe stack. This prevents the pipe elements from pinching and damaging the gasket center leg if present. The enlarged shoulder also permits the groove to be relatively shallow and present a lower internal profile within the pipe element. A lower profile groove at each joint causes less head loss and less turbulence in the fluid flowing through the pipe elements. Additionally, by forming the groove concentric with the shoulder a more uniform engagement between the coupling and the pipe elements is achieved, further lessening the likelihood of leaks.


    Claims

    1. A spin forming machine (136) for forming circumferential shoulder (22) groove (24) and bead (26) in a pipe element (134), said machine (136) includes:

    • a die (138) formed in sections;

    • a spin forming tool (156) mounted in a housing (158);

    • an actuator (166) effecting the motion of the carriage (162) and hence effecting the motion of the spin forming tool (156) toward and away from the die;

    • a housing (158) driven in rotation about axis (160) relatively to carriage (162) on bearings (168) by an electric motor (170) mounted on the carriage;

    characterized in that:

    • the die sections are four (140, 142, 144 and 146), are mounted in bearings and are slidably moveable toward and away from one another using respective actuators (148,150, 152 and 154);

    • the housing (158) has a fixed axis of rotation (160) and is mounted on a carriage (162) which moves along guide rods (164) toward and away from the die (138);

    • the axis of rotation (160) of housing (158) is substantially parallel to the longitudinal axis (161) of the opening defined when the die sections (140, 142, 144 and 146) are brought together.


     
    2. The machine (136) according to claim 1, wherein the spin forming tool (156) moves relatively to the housing (158) in a direction to offset its longitudinal axis (172) from the housing axis of rotation (160) and an actuator (174) mounted on the housing (158) offsets the spin forming tool (156).
     
    3. The machine (136) according to claim 2, wherein the die sections (140) have an inner surface (178) shaped to produce a desired final shape of the outer surface (134a) of the pipe element (134) during spin forming.
     
    4. The machine (136) according to claims 1 to 3, wherein the spin forming tool (156) has an outer surface (180) shaped to cooperate with the inner surfaces (178) of the die sections (140, 142, 144, 146).
     
    5. The machine (136) according to claims 1 to 4, wherein a spring (176) restores the force and moves the spin forming tool's longitudinal axis (172) back into coaxial alignment with the housing axis of rotation (166) (160) when force of the actuator (174) is relieved.
     
    6. The machine (136) of claims 1 to 5, wherein the four die sections (140, 142, 144, 146) are configured in offset pairs (140 and 142, 144 and 146).
     
    7. A method of forming a circumferential bead (26) and groove (24) in a pipe element (134) by using the machine (136) of claims 1 to 6, said method comprising:

    • capturing an end of said pipe element (134) in a die (138);

    • inserting a tool (156) within said pipe element (134);

    • revolving said tool (156) in an orbit about a longitudinal axis of said pipe element (34);

    • increasing the diameter of said orbit while revolving said tool (156) so as to force said tool against an inner surface (134b) of said pipe element (134);

    • conforming said pipe element (134) to said die (138) so as to form said circumferential bead (26) therein, said bead (26) having an apex having larger outer diameter than the outer diameter of the remainder of said pipe element (134);

    • forcing said tool (156) against said inner surface (134b) of said pipe element (134) while revolving said tool (156) in said orbit of increasing diameter causing a portion of said pipe adjacent to said bead (26) to move radially inwardly away from said die (138) thereby forming said groove (24), said groove (24) having a smaller outer diameter than the outer diameter of the remainder of said pipe element (134).


     
    8. The method according to Claim 7, further comprising:

    • conforming said pipe element to said die (138) so as to form a circumferential shoulder (22) therein, said shoulder (22) having a larger outer diameter than the outer diameter of the remainder of said pipe element (134).


     
    9. A method of forming a circumferential shoulder (22), groove (24) and bead (26) in a pipe element (134) by using the machine (136) of claims 1 to 6, said method comprising:

    • capturing an end of said pipe element in a die (138);

    • inserting a tool (156) within said pipe element;

    • revolving said tool (156) in an orbit about a longitudinal axis of said pipe element (134);

    • increasing the diameter of said orbit while revolving said tool so as to force said tool (156) against an inner surface (134b) of said pipe element (134);

    • conforming said pipe element (134) to said die (138) so as to form a circumferential shoulder (22) therein, said shoulder (22) having a larger outer diameter than the outer diameter of the remainder of said pipe element (134);

    • conforming said pipe element (134) to said die (138) so as to form a circumferential bead (26) therein, said bead (26) having an apex with a larger outer diameter than the outer diameter of the remainder of said pipe element (134);

    • forcing said tool (156) against said inner surface (134b) of said pipe element (134) while revolving said tool (156) in said orbit of increasing diameter causing a portion of said pipe between said shoulder (22) and said bead (26) to move radially inwardly away from said die (138) thereby forming said groove (24), said groove (24) having a smaller outer diameter than the outer diameter of the remainder of said pipe element (134).


     


    Ansprüche

    1. Drück- und Fließdrückmaschine (136) zum Ausbilden einer Umfangsschulter (22), einer Nut (24) und einer Wulst (26) in einem Rohrelement (134), wobei die Maschine (136) aufweist:

    • eine in Abschnitte unterteilte Form (138);

    • ein Drück- und Fließdrückwerkzeug (156), das in einem Gehäuse (158) angebracht ist;

    • ein Stellorgan (166) zum Bewirken der Bewegung des Schlittens (162) und damit zum Bewirken der Bewegung des Drück- und Fließdrückwerkzeugs (156) auf die Form zu und von dieser weg;

    • ein Gehäuse (158), das um eine Achse (160) relativ zu dem Schlitten (162) auf Lagern (168) durch einen Elektromotor (170) in Drehung versetzt wird, der auf dem Schlitten angebracht ist;

    dadurch gekennzeichnet, dass:

    • vier Formabschnitte (140, 142, 144 and 146) vorgesehen und unter Verwendung jeweiliger Betätigiungslemente(148, 150, 152 und 154) aufeinander zu und voneinander weg gleitend beweglich sind;

    • das Gehäuse (158) eine feststehende Drehachse (160) aufweist und auf einem Schlitten (162) angebracht ist, der sich entlang von Führungsstangen (164) zu der Form (138) hin und von dieser weg bewegt;

    • die Drehachse (160) des Gehäuses(158) im Wesentlichen parallel zu der Längsachse (161) der Öffnung verläuft, die entsteht, wenn die Formabschnitte (140, 142, 144 and 146) zusammengesetzt werden.


     
    2. Maschine (136) nach Anspruch 1, wobei das Drück- und Fließdrückwerkzeug (156) sich relativ zum Gehäuse (158) in einer Richtung bewegt, um seine Längsachse (172) gegenüber der der Gehäusedrehachse (160) zu versetzen, und ein auf dem Gehäuse (2158) angebrachtes Stellorgan (174) das Drück- und Fließdrückwerkzeug (156) versetzt.
     
    3. Maschine (136) nach Anspruch 2, wobei die Formabschnitte (140) eine Innenseite (178) aufweisen, die derart gestaltet ist, dass sie während des Drück- und Fließdrückvorgangs eine angestrebte Endgestalt der Außenseite (134a) des Rohrelements (134) erzeugt.
     
    4. Maschine (136) nach einem der Ansprüche 1 bis 3, wobei das Drück- und Fließdrückwerkzeug (156) eine Außenseite (180) aufweist, die derart gestaltet ist, das sie mit den Innenseiten (178) der Formabschnitte (140, 142, 144, 146) kooperiert.
     
    5. Maschine (136) nach einem der Ansprüche 1 bis 4, wobei eine Feder (176) zur Kraftrückgewinnung vorgesehen ist und die Drück- und Fließdrückwerkzeug- Längsachse (172) in eine koaxial mit der Gehäusedrehachse (160) fluchtende Ausrichtung rückgestellt wird, wenn die Kraft des Stellorgans (174) verringert wird.
     
    6. Maschine (136) nach einem der Ansprüche 1 bis 5, wobei die vier Abschnitte (140, 142, 146) als versetzte Paare (140 und 142, 144 und 146) konfiguriert sind.
     
    7. Verfahren zum Ausbilden einer Umfangswulst (26) und einer Nut (24) in einem Rohrelement (134) unter Verwendung der Maschine (136) nach einem der Ansprüche 1 bis 6, wobei das Verfahren die Schritte aufweist:

    • Aufnehmen eines Endes des Rohrelements (134) in einer Form (138);

    • Einführen eines Werkzeugs (156) in das Rohrelement (134);

    • Umlaufenlassen des Werkzeugs (156) auf einer Umlaufbahn um eine Längsachse des Rohrelements;

    • Vergrößern des Durchmessers der Umlaufbahn bei umlaufendem Werkzeug (156), um das Werkzeug gegen die Innenseite (134b) des Rohrelements (134) zu drängen;

    • Zur Übereinstimmung bringen des Rohrelements (134) mit der Form (138), um in dem Rohrelement die Umfangswust (26) auszubilden, wobei die Wulst (26) einen Scheitel mit einem größeren Außendurchmesser als der Außendurchmesser des restlichen Rohrelements (134) aufweist;

    • Drängen des Werkzeugs (156) gegen die Innenseite (134b) des Rohrelements (134), während das Werkzeug auf der Umlaufbahn zunehmenden Durchmessers umläuft, wodurch ein Abschnitt des Rohrs benachbart zur Wulst veranlasst wird, sich unter Ausbildung der Nut (24) radial einwärts von der Form (138) weg zu bewegen, wobei die Nut (24) einen kleineren Außendurchmesser als der Außendurchmesser des restlichen Rohrelements (134) aufweist.


     
    8. Verfahren nach Anspruch 7, außerdem aufweisend den Schritt:

    • Zur Übereinstimmung bringen des Rohrelements mit der Form (138), um in diesem eine Umfangsschulter (22) auszubilden, wobei die Schulter (22) einen größeren Außendurchmesser aufweist als der Außendruchmesser des restlichen Rohrelements (134).


     
    9. Verfahren zum Ausbilden einer Umfangsschulter (22), einer Nut (24) und einer Wulst (26) in einem Rohrelement (134) unter Verwendung der Maschine (136) nach einem der Ansprüche 1 bis 6, wobei das Verfahren aufweist:

    • Aufnehmen eines Endes des Rohrelements in einer Form (138);

    • Einführen eines Werkzeugs (156) in das Rohrelement (134);

    • Umlaufenlassen des Werkzeugs (156) auf einer Umlaufbahn um eine Längsachse des Rohrelements;

    • Vergrößern des Durchmessers der Umlaufbahn bei umlaufendem Werkzeug (156), um das Werkzeug gegen die Innenseite (134b) des Rohrelements (134) zu drängen;

    • Zur Übereinstimmung bringen des Rohrelements (134) mit der Form (138), um in dem Rohrelement eine Umfangsschulter (22) auszubilden, wobei die Schulter (22) einen größeren Außendurchmesser als der Außendurchmesser des restlichen Rohrelements (134) aufweist;

    • Zur Übereinstimmung bringen des Rohrelements (134) mit der Form (138), um in dem Rohrelement die Umfangswust (26) auszubilden, wobei die Wulst (26) einen Scheitel mit einem größeren Außendurchmesser als der Außendurchmesser des restlichen Rohrelements (134) aufweist;

    • Drängen des Werkzeugs (156) gegen die Innenseite (134b) des Rohrelements (134), während das Werkzeug auf der Umlaufbahn zunehmenden Durchmessers umläuft, wodurch ein Abschnitt des Rohrs zwischen der Schulter (22) und der Wulst (26) veranlasst wird, sich unter Ausbildung der Nut (24) radial einwärts von der Form (138) weg zu bewegen, wobei die Nut einen kleineren Außendurchmesser als der Außendurchmesser des restlichen Rohrelements (134) aufweist.


     


    Revendications

    1. Machine à repousser (136) pour former un épaulement (22), une gorge (24) et une moulure (26) circonférentiels dans un élément de tuyau (134), ladite machine (136) comprenant :

    • une filière (138) formée en sections ;

    • un outil à repousser (156) monté dans un logement (158) ;

    • un actionneur (166) provoquant le mouvement du chariot (162) et provoquant donc le mouvement de l'outil à repousser (156) vers et en éloignement de la filière ;

    • un logement (158) entraîné en rotation autour d'un axe (160) par rapport au chariot (162) sur des roulements (168) par un moteur électrique (170) monté sur le chariot ;

    caractérisée en ce que :

    • les sections de filière sont au nombre de quatre (140, 142, 144 et 146), sont montées dans des roulements et sont mobiles en coulissement vers et en éloignement les unes des autres à l'aide d'actionneurs respectifs (148, 150, 152 et 154) ;

    • le logement (158) a un axe de rotation fixe (160) et est monté sur un chariot (162) qui se déplace le long de tiges de guidage (164) vers et en éloignement de la filière (138) ;

    • l'axe de rotation (160) du logement (158) est sensiblement parallèle à l'axe longitudinal (161) de l'ouverture définie lorsque les sections de filière (140, 142, 144 et 146) sont rassemblées.


     
    2. Machine (136) selon la revendication 1, dans laquelle l'outil à repousser (156) se déplace par rapport au logement (158) dans une direction pour décaler son axe longitudinal (172) de l'axe de rotation du logement (160) et un actionneur (174) monté sur le logement (158) décale l'outil à repousser (156).
     
    3. Machine (136) selon la revendication 2, dans laquelle les sections de filière (140) ont une surface intérieure (178) formée pour produire une forme finale souhaitée de la surface extérieure (134a) de l'élément de tuyau (134) pendant le repoussage.
     
    4. Machine (136) selon les revendications 1 à 3, dans laquelle l'outil à repousser (156) a une surface extérieure (180) formée pour coopérer avec les surfaces intérieures (178) des sections de filière (140, 142, 144 et 146).
     
    5. Machine (136) selon les revendications 1 à 4, dans laquelle un ressort (176) rétablit la force et replace l'axe longitudinal (172) de l'outil à repousser en alignement coaxial avec l'axe de rotation du logement (160) lorsque la force de l'actionneur (174) est relâchée.
     
    6. Machine (136) selon les revendications 1 à 5, dans laquelle les quatre sections de filière (140, 142, 144 et 146) sont configurées en paires décalées (140 et 142, 144 et 146).
     
    7. Procédé de formation d'une moulure (26) et d'une gorge (24) circonférentielles dans un élément de tuyau (134) en utilisant la machine (136) des revendications 1 à 6, ledit procédé comprenant les étapes consistant à :

    • capturer une extrémité dudit élément de tuyau (134) dans une filière (138) ;

    • insérer un outil (156) à l'intérieur dudit élément de tuyau (134) ;

    • faire tourner ledit outil (156) en orbite autour d'un axe longitudinal dudit élément de tuyau (134) ;

    • augmenter le diamètre de ladite orbite tout en faisant tourner ledit outil (156) de façon à forcer ledit outil contre une surface intérieure (134b) dudit élément de tuyau (134) ;

    • conformer ledit élément de tuyau (134) à ladite filière (138) de façon à y former ladite moulure circonférentielle (26), ladite moulure (26) ayant un sommet de diamètre extérieur plus grand que le diamètre extérieur du reste dudit élément de tuyau (134) ;

    • forcer ledit outil (156) contre ladite surface intérieure (134b) dudit élément de tuyau (134) tout en faisant tourner ledit outil (156) dans ladite orbite de diamètre accru, amenant une portion dudit tuyau adjacente à ladite moulure (26) à s'éloigner radialement vers l'intérieur de ladite filière (138) formant ainsi ladite gorge (24), ladite gorge (24) ayant un diamètre extérieur plus petit que le diamètre extérieur du reste dudit élément de tuyau (134).


     
    8. Procédé selon la revendication 7, comprenant en outre l'étape consistant à :

    • conformer ledit élément de tuyau à ladite filière (138) de façon à y former un épaulement circonférentiel (22), ledit épaulement (22) ayant un diamètre extérieur plus grand que le diamètre extérieur du reste dudit élément de tuyau (134).


     
    9. Procédé de formation d'un épaulement (22), d'une gorge (24) et d'une moulure (26) circonférentiels dans un élément de tuyau (134) en utilisant la machine (136) des revendications 1 à 6, ledit procédé comprenant les étapes consistant à :

    • capturer une extrémité dudit élément de tuyau dans une filière (138) ;

    • insérer un outil (156) à l'intérieur dudit élément de tuyau ;

    • faire tourner ledit outil (156) en orbite autour d'un axe longitudinal dudit élément de tuyau (134) ;

    • augmenter le diamètre de ladite orbite tout en faisant tourner ledit outil de façon à forcer ledit outil (156) contre une surface intérieure (134b) dudit élément de tuyau (134) ;

    • conformer ledit élément de tuyau (134) à ladite filière (138) de façon à y former un épaulement circonférentiel (22), ledit épaulement (22) ayant un diamètre extérieur plus grand que le diamètre extérieur du reste dudit élément de tuyau (134) ;

    • conformer ledit élément de tuyau (134) à ladite filière (138) de façon à y former une moulure circonférentielle (26), ladite moulure (26) ayant un sommet de diamètre extérieur plus grand que le diamètre extérieur du reste dudit élément de tuyau (134) ;

    • forcer ledit outil (156) contre ladite surface intérieure (134b) dudit élément de tuyau (134) tout en faisant tourner ledit outil (156) dans ladite orbite de diamètre accru, amenant une portion dudit tuyau entre ledit épaulement (22) et ladite moulure (26) à s'éloigner radialement vers l'intérieur de ladite filière (138) formant ainsi ladite gorge (24), ladite gorge ayant un diamètre extérieur plus petit que le diamètre extérieur du reste dudit élément de tuyau (134).


     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description