Abstract:
Methods, gaskets, and couplings for connecting two pipes are disclosed. One embodiment of the method includes the steps of placing the assembled coupling over one end of a pipe, aligning the second pipe with the first pipe, sliding the coupling off the end of the first pipe so that a portion of the coupling is around each pipe, and securing the coupling.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. application Ser. No. 12/490,113, filed Jun. 23, 2009, which claims priority to U.S. Provisional Application No. 61/133,300, filed Jun. 30, 2008, both of which are hereby specifically incorporated by reference herein in their entireties. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The invention is directed to coupling devices used to join sections of pipe and methods of their use and, in particularly, methods and systems of coupling devices that are installable in one unit without disassembly. 
         [0004]    2. Background of the Invention 
         [0005]    A common type of pipe coupling device used to join two pipes employs a housing consisting of two half-circular elements joined together with bolts at either end. Usually the housing is used to secure two lengths of pipe together. In order to prevent leaking between the two pipes, a gasket is usually secured around the seam created at the junction of the two pipes. The two halves of the housing surround the gasket and press the gasket around the seam.  FIG. 1  shows a basic coupling device  100 . Coupling device  100  includes an upper housing  105  and a lower housing  106 . Upper housing  105  and lower housing  106  are held together by bolts  115 . 
         [0006]    In order to install the device, workers must disassemble the entire apparatus and remove the gasket from the housing. Approximately half of the gasket is then forced over one end of one pipe. An end of the other pipe is forced into the remaining portion of the gasket, thereby joining the two pipes together. To secure the pipes, the two halves of the housing are placed around the gasket and then bolts or other fastening devices are used to complete the installation. In most cases, the inner diameter of the gasket is slightly smaller than the outer diameter of the pipes. Therefore, the worker must stretch the gasket around the pipe ends. 
         [0007]    Another device for joining two pipes is described in U.S. Pat. No. 7,401,819, herein incorporated in its entirety. The device described in U.S. Pat. No. 7,401,819 is a traditional coupling and a gasket that fits within the coupling. The gasket has a tongue that protrudes from the inner surface of the gasket. To join the pipes, one pipe is inserted into the gasket up to the tongue and then the other pipe is inserted into the other end of the gasket up to the tongue. 
         [0008]    Each of these devices and methods takes time and can cause errors in the alignment and joining of the pipes. Therefore it is desirable to have a coupling that can be easily installed without disassembling prior to use. 
       SUMMARY 
       [0009]    The present invention overcomes the problems and disadvantages associated with current strategies and designs and provides new tools and methods of coupling pipes. 
         [0010]    One embodiment of the invention is directed to a coupling for joining two pipes. The coupling includes, an upper housing, a lower housing, at least one fastening device for securing the upper housing to the lower housing, and a gasket positioned within the upper and lower housings. The gasket is includes two primary seals, one on each outer edge of the gasket, and at least two secondary seals on a rib protruding from the inner surface of the gasket and between the two primary seals. The primary seals are adapted so that the gasket slides completely over the end of one pipe without disassembling the coupling. 
         [0011]    In another embodiment, the fastening devices are selected from the group including bolts, clips, snap-couplings, rivets, and ties. In certain embodiments, the inner diameter of the gasket is larger than the outer diameter of the pipes. In certain embodiments, the outer diameter of the gasket is concave. In certain embodiments, each primary seal includes a gripping extension. The gripping extension is adapted to grab the end of a pipe as the gasket slides over the end of the pipe. 
         [0012]    In certain embodiments, each primary seal has stepped ribs on the inner surface of the gasket. In certain embodiments, a portion of each of the upper housing and the lower housing is chamfered. The chamfered sections are on the inner surface of each of the upper housing and the lower housing adjacent to where the upper housing and the lower housing meet. 
         [0013]    In certain embodiments, the coupling includes spacers to separate the upper housing from the lower housing. In certain embodiments, the spacers are removable. In certain embodiments, the spacers are permanent and compressible. In certain embodiments, the spacers are springs. 
         [0014]    In certain embodiments, the primary seals have rounded interior ends. In certain embodiments, the primary seals have interior ends that angle toward the outer surface of the gasket. In certain embodiments, the corners of the outer surface of the gasket are concave. In certain embodiments, there are three secondary seals. 
         [0015]    In certain embodiments, the coupling includes at least one slot in the outer surface of the gasket. In certain embodiments, there is one continuous slot around the circumference of the gasket. In certain embodiments, there are a plurality of slots around the circumference of the gasket. In certain embodiments, the coupling includes at least one retaining device. In certain embodiments, the retaining device is a single wire surrounding the upper housing and the lower housing. In certain embodiments, the gasket is lubricated. In certain embodiments, the lower housing and the fastening device is one element attached to the upper housing. 
         [0016]    Another embodiment of the invention is directed toward a gasket. The gasket includes two primary seals, one on each outer edge of the gasket, and at least two secondary seals on a rib protruding from an inner surface of the gasket and between the two primary seals. The primary seals are adapted so that the gasket slides completely over the end of a pipe without disassembling the coupling. 
         [0017]    In certain embodiments, the inner diameter of the gasket is larger than the outer diameter of the pipe. In certain embodiments, the outer diameter of the gasket is concave. In certain embodiments, each primary seal includes a gripping extension. The gripping extension is adapted to grab the end of a pipe as the gasket slides over the end of the pipe. In certain embodiments, each primary seal has stepped ribs on the inner surface of the gasket. In certain embodiments, the primary seals have rounded interior ends. In certain embodiments, the primary seals have interior ends that angle toward the outer surface of the gasket. In certain embodiments, the corners of the outer surface of the gasket are concave. 
         [0018]    In certain embodiments, there are three secondary seals. In certain embodiments, the gasket includes at least one slot in the outer surface of the gasket. In certain embodiments, there is one continuous slot around the circumference of the gasket. In certain embodiments, there are a plurality of slots around the circumference of the gasket. Another embodiment of the invention is a method of coupling two pipes. The method includes, placing an assembled coupling over one end of one pipe, aligning a second pipe with the first pipe, sliding the coupling off the end of the first pipe so that at least a portion of the coupling is around each pipe, and securing the coupling. 
         [0019]    In certain embodiments, the coupling includes an upper housing, a lower housing, at least one fastening device coupling the upper housing to the lower housing, and a gasket positioned within the upper and lower housings. The gasket is comprised of two primary seals, one on each outer edge of the gasket, and at least two secondary seals on a rib protruding from an inner surface of the gasket and between the two primary seals. The primary seals are adapted so that the gasket slides completely over the end of the one. 
         [0020]    In certain embodiments, the step of placing an assembled coupling over one end of a first pipe is completed without disassembling the coupling. In certain embodiments, the step of securing the coupling is completed by tightening the fastening devices. Certain embodiments further include the step of aligning the coupling with a groove in each pipe. In another embodiment, the fastening devices are selected from the group including of bolts, clips, snap-couplings, rivets, and ties. In certain embodiments, the inner diameter of the gasket is larger than the outer diameter of the pipes. In certain embodiments, the outer diameter of the gasket is concave. In certain embodiments, each primary seal includes a gripping extension. The gripping extension is adapted to grab the end of a pipe as the gasket slides over the end of the pipe. 
         [0021]    In certain embodiments, each primary seal has stepped ribs on the inner surface of the gasket. In certain embodiments, a portion of each of the upper housing and the lower housing is chamfered. The chamfered sections are on the inner surface of each of the upper housing and the lower housing adjacent to where the upper housing and the lower housing meet. 
         [0022]    In certain embodiments, the coupling includes spacers to separate the upper housing from the lower housing. In certain embodiments, the spacers are removable. In certain embodiments, the spacers are permanent and compressible. In certain embodiments, the spacers are springs. 
         [0023]    In certain embodiments, the primary seals have rounded interior ends. In certain embodiments, the primary seals have interior ends that angle toward the outer surface of the gasket. In certain embodiments, the corners of the outer surface of the gasket are concave. In certain embodiments, there are three secondary seals. 
         [0024]    In certain embodiments, the coupling includes at least one slot in the outer surface of the gasket. In certain embodiments, there is one continuous slot around the circumference of the gasket. In certain embodiments, there are a plurality of slots around the circumference of the gasket. In certain embodiments, the coupling includes at least one retaining device. In certain embodiments, the retaining device is a single wire surrounding the upper housing and the lower housing. In certain embodiments, the gasket is lubricated. In certain embodiments, the lower housing and the fastening device is one element attached to the upper housing. 
         [0025]    Other embodiments and advantages of the invention are set forth in part in the description, which follows, and in part, may be obvious from this description, or may be learned from the practice of the invention. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0026]    The invention is described in greater detail by way of example only and with reference to the attached drawings, in which: 
           [0027]      FIG. 1  is a basic coupling device. 
           [0028]      FIGS. 2   a - c  show the steps of installing a coupling of the instant invention. 
           [0029]      FIGS. 3   a - c  show a cut away view of  FIGS. 2   a - c.    
           [0030]      FIG. 4  is a isometric view of an embodiment of a gasket of the instant invention. 
           [0031]      FIG. 5  is a cut away view of an embodiment of a gasket of the instant invention. 
           [0032]      FIGS. 6   a - d  are cut away views of another embodiment of a gasket of the instant invention. 
           [0033]      FIGS. 7   a - b  are cut away views of another embodiment of a gasket of the instant invention. 
           [0034]      FIG. 8  is a side view of an embodiment of the coupling of the instant invention. 
           [0035]      FIG. 9  is a side view of another embodiment of the coupling of the instant invention. 
           [0036]      FIG. 10  is a side view of another embodiment of the coupling of the instant invention. 
           [0037]      FIG. 11   a - b  are a cut away views of another embodiment of a gasket of the instant invention. 
           [0038]      FIG. 12  is a cut away view of another embodiment of a gasket of the instant invention. 
           [0039]      FIG. 13  is a cut away view of another embodiment of a gasket of the instant invention. 
           [0040]      FIG. 14  is a cut away view of another embodiment of a gasket of the instant invention. 
           [0041]      FIGS. 15   a - c  are views of another embodiment of the coupling of the gasket of the instant invention. 
           [0042]      FIG. 16  is a cut away view of a device for rolling a groove in a pipe. 
           [0043]      FIG. 17  is a side view of another embodiment of the gasket. 
       
    
    
     DETAILED DESCRIPTION 
       [0044]    As embodied and broadly described herein, the disclosures herein provide detailed embodiments of the invention. However, the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. Therefore, there is no intent that specific structural and functional details should be limiting, but rather the intention is that they provide a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention. 
         [0045]    A problem in the art capable of being solved by the embodiments of the present invention is quickly and easily joining two pipes together without first disassembling the coupling. It has been surprisingly discovered that certain configurations of the gasket allow joining two pipes together without having to disassemble the coupling. The gasket may have certain elements that will be further described below that allow it to slide completely over one pipe before the two pipes are joined. 
         [0046]      FIGS. 2   a - 2   c  show the steps of a method of installing an embodiment of the invention. In  FIG. 2   a , coupling  200  is placed completely over one end of pipe  210 . Coupling  200  remains held together by bolts  215  and surrounds a gasket that is in contact with pipe  210 . In  FIG. 2   b , pipe  220  is brought into alignment with pipe  210  and an end of one pipe is placed adjacent to an end of the other pipe. Preferably pipe  210  and pipe  220  are in direct contact with each other, however in certain circumstances a slight gap is permissible. In the preferred embodiment, no part of the gasket protrudes between pipe  210  and  220 , however, in certain embodiments, a portion of the gasket protrudes between pipe  210  and  220 . In  FIG. 2   c , coupling  200  is slid over the end of pipe  220  so that a portion of coupling  200  surrounds pipe  210  and a portion of coupling  200  surround pipe  220 . Preferably, coupling  205  is equally distributed over pipe  210  and  220 . Bolts  215  are then tightened to fully secure coupling  200  over the two pipes and thus join the two pipes in fluid communication. The ends of each pipe may have a groove  222  into which an inner diameter of coupling  200  fits upon completion of the assembly of coupling  200  and pipes  210  and  220 .  FIGS. 3   a - 3   c  show the above described steps in a cut away, side view. 
         [0047]    Bolts  215  may be of any material including but not limited to plastic, metal, fiber, and synthetic materials. Bolts  215  can be of any dimension. In certain embodiments, the heads of bolts  215  will break off at a predetermined torque to prevent over tightening of bolts  215 . In other embodiments bolts  215  may be replaced with other fastening devices. Any fastening device may be used, including clips, snap-couplings, rivets, and ties. 
         [0048]    Pipes  210  and  220  can be used for transporting any material, including, but not limited to, water, oil, and gas. Pipes  210  and  220  may be of any size and coupling  200  is of any complementary size to fit over and join pipes  210  and  220 . Preferably, pipes  210  and  220  are of the same size; however, in certain embodiments of coupling  200 , pipes of different sizes are joined. 
         [0049]      FIG. 4  is an isometric view of an embodiment of a gasket  430  of the invention. Gasket  430  can be made of any material that is capable of forming a seal and deforming. For instance, gasket  430  can be made from EPDM, nitrile, fluro-elastomer, silicone, plastic, rubber, fiber, synthetic materials, resin, etc. Furthermore, gasket  430  may be produced using injection molding, extrusion, compression molding, machining, casting, 3-D printing, or any other method known in the art. Gasket  430  is preferably a continuous solid mass. 
         [0050]      FIG. 5  is a cut away view of an embodiment of a gasket  530 . Gasket  530  preferably has an inner diameter that is larger than the outer diameter of the pipes around which gasket  530  is to be installed. Furthermore, the inner diameter of gasket  530  is preferably larger than the inner diameter of a standard gasket. Such a configuration will assist in ease of installation of gasket  530 . In certain embodiments, the outer diameter of gasket  530  is also larger than the outer diameter of a standard gasket. Having a larger outer diameter assists in compressing gasket  530  into the pipes around which gasket  530  is installed. 
         [0051]    Gasket  530 , in certain embodiments, has a primary seal  535  on either side of gasket  530 , which, upon complete assembly of the coupling, is press into the outer walls of the pipes. In certain embodiments, gasket  530  has an internal rib  540  positioned between the two primary seals  535 . Internal rib  540  includes at least two secondary seals  545  on either end thereof Secondary seals  545  are positioned so that upon complete assembly of the coupling each secondary seal  545  is pressed into the outer walls of the pipes and is adjacent to the seam between the two pipes. The positioning of primary seals  535  and secondary seals  545  relative to the two pipes upon complete assembly of the coupling can be seen more clearly in  FIG. 3   c.    
         [0052]    In certain embodiments, the outer diameter of gasket  530  is outwardly curved or concave. The curve assists in compressing gasket  530  into the pipes and completing the seal between gasket  530  and the pipes upon complete assembly of the coupling.  FIG. 17  shows another embodiment of a gasket  1700  where at least a portion of the outer surface  1799  is flat. 
         [0053]      FIGS. 6   a - d  show an embodiment of coupling  600  where primary seals  635  contain extensions  636  to grip the edge of pipe  620 . In certain embodiments, coupling  600  is held open by gasket  640  prior to insertion over pipe  620 . See  FIG. 6   a . As coupling  600  and gasket  630  slide over pipe  620 , extensions  636  of primary seal  635  grab the edge of pipe  620 . See  FIG. 6   b . Upon further force, primary seal  635  will snap into position around pipe  620  as shown in  FIG. 6   c . Pipe  610  is then aligned with pipe  620  and coupling  600  and gasket  630  are slid back off pipe  620  and onto pipe  610  so that a portion of coupling  600  and gasket  630  are in contact with each pipe. Coupling  600  can then be tightened and engage a groove  612  and  622  at the end of each of pipe  610  and  620 , respectively. See  FIG. 6   d.    
         [0054]      FIG. 7   a  shows an embodiment of a gasket  730 . In gasket  730 , primary seals  735  have stepped ribs  737  on the inner surface of gasket  730 .  FIG. 7   b  shows an enlarged view of the primary seal encircled in  FIG. 7   a . It should be noted that each primary seal is preferably a mirror image of the other primary seal, thus the discussion of the primary seal in  FIG. 7   b  applies to the other primary seal. While  FIG. 7   b  shows two stepped ribs  737 , any number of stepped ribs may be included on primary seal  735 . In certain embodiments; each rib includes a first portion  737   a  that is substantially parallel to the center line CL, shown in  FIG. 7   a , and a second portion  737   b  that is substantially perpendicular to first portion  737   a.  In other embodiments second portion  737   b  is not substantially perpendicular to first portion  737   a  but, instead, is oriented at an acute or obtuse angle to first portion  737   a.  Preferably, first portion  737   a  is longer than second portion  737   b,  however any ratio can be used. 
         [0055]      FIG. 8  shows an embodiment of coupling  800 . Coupling  800  consists of two housings  805  and  806  held together by bolts  815 . Both upper housing  805  and lower housing  806  have inner portions  807  and  808 , respectively, which are chamfered. Chamfered sections  807  and  808  consist of portions of housings  805  and  806  that have been removed to widen the inner diameter of the point of contact between the two housings. Chamfered sections  807  and  808  may be created by grinding, machining or melting away a portion of housings  805  and  806  or may be included during the production of housings  805  and  806 . By adding chamfered sections  807  and  808 , pipe  820  can fit through coupling  800  with housings  805  and  806  in a closer configuration than if chamfered sections  807  and  808  were not present. Thus, bolts  815  can be shorter. 
         [0056]      FIG. 9  shows another embodiment of a coupling  900 . Coupling  900  includes spacers  980  between upper housing  905  and lower housing  906 . Spacers  980  are placed adjacent to bolts  915  and keep upper housing  905  and lower housing  906  at a predetermined separation. The separation between upper housing  905  and lower housing  906  helps in inserting a pipe into coupling  900 . Spacers  980  may be removable prior to tightening bolts  915 . In the removable embodiment, spacer  980  may be either disposable or reusable. In other embodiments, spacers  980  are permanent and compress upon tightening of bolts  915 . The compressible embodiment may include scored sections to facility collapse. Although shown as rectangular, spacers  980  may be of any shape or size so long as spacers  980  keep upper housing  905  and lower housing  915  at a predetermined separation. Spacers  980  may be made of any material, including, but not limited to, metal, plastic, fiber, foam, natural materials, rubber, and silicone. 
         [0057]      FIG. 10  shows an embodiment of the coupling  1000 , similar to the coupling  900  shown in  FIG. 9 . In coupling  1000 , springs  1085  replaces spacers  980  of coupling  900 . Springs  1085  are threaded over bolts  1015  and be used to keep upper housing  1005  and lower housing  1006  separated. Springs  1085  compress when bolts  1015  are tightened, thereby eliminating the separation between upper housing  1005  and lower housing  1006 . Springs  1085  may be of any material, including but not limited to metal, foam, and plastic. 
         [0058]      FIG. 11   a  shows a cut away view of an embodiment of gasket  1130 . In gasket  1130 , primary seals  1135  of gasket  1130  have rounded ends  1136 . Rounded ends  1136  are located on the inside edge of primary seals  1135 . Rounded ends  1136  may be of any radius and may be of any shape, including ovoid and circular. Rounded ends  1136  help gasket  1130  slide over a pipe. Alternatively, as shown in  FIG. 12 , ends  1236  are angled toward the outer diameter of gasket  1230 . Angle A may be of any angle greater than zero. Additionally, in certain embodiments, gasket  1130  of  FIG. 11   a , has the upper, outer corners  1132  removed or concave. Removed corners  1132  may be of any shape or size. Removed corners  1132  assist in keeping the upper and lower housings apart prior to tightening the bolts to further ease sliding the coupling over a pipe end.  FIG. 11   b  shows another embodiment of a gasket with rounded ends. 
         [0059]      FIG. 13  shows a cut away view of an embodiment of gasket  1330 . As in the embodiment of gasket  530  shown in  FIG. 5 , the embodiment of gasket  1330  shown in  FIG. 13  includes primary seals  1335  and internal rib  1340 . However, in gasket  1330 , internal rib  1340  includes three secondary seals  1345 . The middle secondary seal increases stiffness of internal rib  1340  and improves the seal between the pipes and gasket  1330 . Additionally, the middle secondary seal may compensate for any errors in alignment of the pipes around which gasket  1330  is placed. The middle secondary seal may be equal, larger, or smaller in size to the outer secondary seals. 
         [0060]      FIG. 14  shows a cut away view of an embodiment of gasket  1430 . Gasket  1430  also includes primary seals  1435 , internal rib  1440 , and secondary seals  1445 . In certain embodiments of gasket  1430  there is at least one slot  1490  in the outer diameter of gasket  1430 . Preferably, slot  1490  is located along the centerline of gasket  1430 ; however slot  1490  can be at any location. In certain embodiments of gasket  1430 , slot  1490  is continuous around the entire diameter of gasket  1430 . In other embodiments of gasket  1430 , slot  1490  is intermittent around the diameter of gasket  1430 . Slot  1490  may be of any shape, including but not limited to circular, ovoid, triangular, square, and rectangular. In the preferred embodiment, gasket  1430  will have one slot  1490 ; however any number of slots may be used. Slot  1490  lessens the amount of material used in gasket  1430  and provides extra free volume to prevent over-compression of gasket  1430 . 
         [0061]      FIGS. 15   a - 15   c  show an embodiment of coupling  1500  that includes at least one retainer  1586 . Retainers  1586  may be made of any material, including metal, plastic, rubber, synthetic materials, and fibers. In certain embodiments of coupling  1500 , the upper housing  1505  and lower housing  1506  are adapted to hold retainers  1586  via notches  1587 . Retainers  1586  prevent upper housing  1505  and lower housing  1506  from separating during installation of coupling  1500 . Furthermore, retainers  1586  add stability and rigidity to coupling  1500  during installation and shipping. Retainers  1586  may be permanent or removable. In the removable embodiment, retainers  1586  may be disposable. While rectangular retainers  1586  are shown, any shape may be utilized. Furthermore, retainers  1586  may have any dimensions. 
         [0062]    In certain embodiments, the pips ends are given a groove prior to assembly. Such grooves and a device to create such grooves can be found in U.S. Pat. No. 6,196,039, herein incorporated in its entirety.  FIG. 16  shows an embodiment of a grove roller. Outside and inside rollers  1602 ,  1604  are used to form an inward groove  1606  near an end  1616  of pipe  1608 . A peripheral surface of outside roller  1602  includes a first protrusion  1610  for creating groove  1606 , and a second protrusion  1612 , which is positioned closer to pipe end  1616  than protrusion  1610  when forming groove  1606 . A peripheral surface of inside roller  1604  includes a first indentation or grooving notch  1620  configured to receive first protrusion  1610 , and which acts with first protrusion  1610  of top roller  1602  to form groove  1606 . Inside roller also includes a second indentation or notch  1622  configured to receive the second protrusion, and which provides space for pipe end  1616 . 
         [0063]    Second protrusion  1612  is configured to help increase the height of a wall edge  1614  of groove  1606  and to resist flaring of pipe end  1616 . Second protrusion  1612  includes a chamfered surface  1613  facing toward first protrusion  1610 , and is rounded at the top and towards the opposite side. 
         [0064]    Chamfered surface is at an angle β from a perpendicular to the rotational axis of outside roller  1602 , which can be in a range of about 0° to about 70°. 
         [0065]    When a radial load, L, is applied to outside roller  1602 , it is believed that protrusion  1612  applies a radial load, R, and an axial load, A, to pipe end  1616 . The axial load tends to push the pipe material toward protrusion  1610 . This action produces a higher groove edge wall  1614  than typical with a conventional outside roller (e.g., an outside roller without a protrusion  1612 ). Groove edge wall  1614  is formed with a substantially vertical face  225 , which intersects an adjacent arcuate portion  1630  having a tangent at an intersection angle d to the vertical face  1625 . It is believed that protrusion  1612  with chamfered surface  1613  tends to minimize intersection angle d, which helps to minimize shearing of the groove wall. A small intersection angle d provides a steeper groove edge wall  1614 . This is advantageous because it improves the attachment of the pipe to the coupling, increasing the pressure rating of the joint and the ability of the joint to resist bending. 
         [0066]    The radial load R applied to pipe  1608  by protrusion  1612  also acts to resist flaring of pipe end  1616 , tending to keep pipe end  1616  more parallel with the central axis of pipe  1608 . Reduced flaring is advantageous because it improves the go sealing of a gasket against the pipe. Protrusion  1612  produces a small secondary groove  1638  having a rounded profile. 
         [0067]    Outside roller  1602  and inside roller  1604  each include a respective aligning element configured to interact with the other aligning element to align the outside and inside rollers when forming the groove. Outside roller  1602  has an alignment bead  1615 , which appears as a finger in profile, and an alignment slot  1617 . Inside roller  1604  includes a corresponding mating alignment slot  1619  which is configured to receive alignment bead  1615 . Alignment slot  1619  is provided between facing walls of inboard and outboard alignment beads  1621 ,  1623 , which also appear as fingers in profile. 
         [0068]    Alignment slot  1617  of outside roller  1602  is configured to receive alignment bead  1621 . Alignment bead  1615  has a diameter which is less than the diameter of either protrusion  1610  or protrusion  1612 . Slot  1617  extends well into outside roller  1602 . Outside roller  1602  tends to screw out when roll forming groove  1606  on pipe  1608 . Therefore, an alignment surface  1626  on alignment bead  1615  that faces protrusion  1610  contacts a second alignment surface  1628  on alignment bead  1621 . This maintains alignment of outside roller  1602  with inside roller  1604 . 
         [0069]    In operation, pipe  1608  is positioned by the operator against a pipe abutment surface  1642  of protrusion  1621  of inside roller  1604 . Outside roller  1602  is brought down (arrow, L) by a manually operated hydraulic actuator (not shown) to form groove  1606 . A pipe stand (not shown) can be used to support pipe  1608  during groove rolling. Positioning rollers provide an offset angle as described in Chatterley et al. U.S. Pat. No. 5,570,603. Positioning the pipe with an offset angle causes outside roller  1602  to produce a torque which tends to draw pipe  1608  inward between the rollers  1602 ,  1604 , thus restricting pipe  1608  from spiraling out. Positioning rollers, along with the weight of pipe  1608 , also act to resist a tendency of pipe  1608  to lift off the support during groove rolling. 
         [0070]    In certain embodiments, the gasket is lubricated before assembly of the coupling. Any lubrication can be used, including but not limited to, oils, fats, synthetic lubricants, and silicon oil. In other embodiments, the lubrication is applied to the pipes before insertion into the gasket. 
         [0071]    In certain embodiments, the lower housing and bolts are replaced with one u-bolt that is secured to the upper housing at each end thereof. The u-bolt can be made of any material including, plastic, metal, fiber, and synthetic materials. 
         [0072]    Other embodiments and uses of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. All references cited herein, including all publications, U.S. and foreign patents and patent applications, are specifically and entirely incorporated by reference. It is intended that the specification and examples be considered exemplary only with the true scope and spirit of the invention indicated by the following claims. Furthermore, the term “comprising of” includes the terms “consisting of” and “consisting essentially of.”