Abstract:
An apparatus and method according to which the apparatus includes a pair of connected arcuate members for clamping around a pipe, with each arcuate member including at least one protrusion. The arcuate members have a first material hardness and at least a portion of the at least one protrusion has a second material hardness that is greater than the first material hardness so that the portion penetratingly engages the pipe when the arcuate members are clamped around the pipe.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 10/971,407, filed on Oct. 22, 2004. 
     
    
     BACKGROUND 
       [0002]    The present invention relates in general to an apparatus for installation on a pipe and in particular to an apparatus employed in the restraint of connected pipes to prevent the separation thereof. 
         [0003]    A conventional connection that joins two adjacent pipes in a fluid-transporting pipeline system is sometimes subjected to internal hydrostatic pressure and/or other external and/or internal forces that tend to deflect or separate one pipe from the other. To combat this separation, a pipe-restraining assembly may be installed across the connection between the two pipes to penetratingly engage and maintain the pipes in a fixed position relative to each other. 
         [0004]    However, a typical pipe-restraining assembly may not be suitable for all types of pipe materials. That is, the ability of the pipe-restraining assembly to penetratingly engage and restrain a pipe is dependent upon the pipe surface having a material hardness that is relatively low. Thus, the pipe-restraining assembly may not be able to prevent the axial separation of pipes having relatively high material hardness levels. 
         [0005]    Therefore, what is needed is an apparatus for installation on a pipe and an accompanying method that, among other things, may be used to overcome the above-described problem. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of a pipe-restraining assembly according to an embodiment of the present invention and clamped around connected pipes. 
           [0007]      FIG. 2  is an exploded view of the pipe-restraining assembly of  FIG. 1 . 
           [0008]      FIG. 3  is a detailed perspective view of a portion of the pipe-restraining assembly shown in  FIG. 2 . 
           [0009]      FIG. 4  is an elevation view of the pipe-restraining assembly of  FIG. 1 . 
           [0010]      FIG. 5  is another elevation view of the pipe-restraining assembly of  FIG. 1 . 
           [0011]      FIG. 6  is a partial perspective/partial section view of a component of a pipe-restraining assembly according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Referring to  FIGS. 1-2 , a pipe-restraining assembly according to an embodiment of the present invention is generally referred to by the reference numeral  10  and is designed to be installed on connected pipes  12  and  14 . The pipe  14  includes a bell  14   a  which receives a conventional spigot extending from the pipe  12  (spigot not shown). The pipes  12  and  14  are sealingly engaged in any conventional manner, and may be made of any conventional pipe material such as, for example, polyvinylchloride (PVC) or ductile iron. 
         [0013]    The assembly  10  includes two spaced pairs of arcuate members  16   a  and  16   b,  and  18   a  and  18   b.  Each pair of arcuate members  16   a  and  16   b,  and  18   a  and  18   b,  forms a ring that envelops portions of and clamps around the pipes  12  and  14 , respectively. 
         [0014]    As more clearly shown in  FIG. 3 , with continuing reference to  FIGS. 1-2 , opposing flange members or ears  20   a  and  20   b  extend outward from each end of the arcuate member  16   a.  Each ear  20   a  and  20   b  includes a chamfer  22   a  and  22   b  and a horizontal surface  24   a  and  24   b,  respectively. Openings or bores  26   a  and  26   b  are formed through the ears  20   a  and  20   b,  respectively. Lugs  28   a  and  28   b  extend from the arcuate member  16   a  and are positioned so that the spacing between the ear  20   a  and the lug  28   a,  and the spacing between the ear  20   b  and the lug  28   b,  are equal along the curved length of the arcuate member. Each lug  28   a  and  28   b  defines a through-opening or bore  28   a ′ and  28   b ′, respectively. 
         [0015]    The arcuate member  16   a  defines a curved surface  30 , with the opposing ends of the curved surface  30  terminating at the chamfers  22   a  and  22   b.  A plurality of protrusions or ridges  32   a,    32   b,    32   c  and  32   d  extend radially inward from the curved surface  30  so that the distal ends of the ridges  32   a - 32   d  are radially offset from the curved surface  30 . The ridges  32   a - 32   d  also extend along the length of the curved surface  30 . The curved surface  30 , and the ridges  32   a - 32   d,  include opposing portions  34   a  and  34   b  which are substantially defined by and substantially extend from the ears  20   a  and  20   b,  and to the lugs  28   a  and  28   b,  respectively. At least some of the material in each of the portions  34   a  and  34   b  has a material hardness that is higher than the remainder of the arcuate member  16   a,  including the remainder of the curved surface  30  and the ridges  32   a - 32   d.  It is understood that the portions  34   a  and  34   b  may be caused to have a material hardness that is higher than the remainder of the arcuate member  16   a  by performing a material-hardening process of such portion such as, for example, a conventional heat treating process. 
         [0016]    The arcuate members  16   b,    18   a  and  18   b  are identical to the arcuate member  16   a  and thus will not be described in detail. Parts of the arcuate members  16   b,    18   a  and  18   b  corresponding to identical parts of the arcuate member  16   a  are given the same reference numerals. 
         [0017]    Referring to  FIGS. 4-5 , with continuing reference to  FIGS. 1-3 , bolts  36   a  and  36   b  extend through the vertically-aligned bores  26   a  and  26   b  of each arcuate member  16   a  and  16   b.  Nuts  38   a  and  38   b  are threadably engaged with the bolts  36   a  and  36   b,  respectively, and contact the ears  20   a  and  20   b,  respectively, thereby connecting the arcuate members  16   a  and  16   b  and clamping the members around the pipe  12 . The surface  24   a  of each arcuate member  16   a  and  16   b  contacts the corresponding surface  24   a  of the other arcuate member, and the surface  24   b  of each arcuate member contacts the corresponding surface  24   b  of the other arcuate member. The ridges  32   a - 32   d  of each arcuate member  16   a  and  16   b  penetratingly engage the pipe  12 . 
         [0018]    Likewise, bolts  40   a  and  40   b  extend through the vertically-aligned bores  26   a  and  26   b  of the arcuate members  18   a  and  18   b,  respectively, and are threadably engaged with nuts  42   a  and  42   b,  respectively. These threaded engagements connect the arcuate members  18   a  and  18   b  and clamp the members around the pipe  14 . The surface  24   a  of each arcuate member  18   a  and  18   b  almost contacts or contacts the corresponding surface  24   a  of the other arcuate member, and the surface  24   b  of each arcuate member almost contacts or contacts the corresponding surface  24   b  of the other arcuate member. The ridges  32   a - 32   d  of each arcuate member  18   a  and  18   b  penetratingly engage the pipe  14 . 
         [0019]    A tie rod  43  extends through each aligned bore  28   a ′ of the arcuate members  16   b  and  18   b  so that the tie rod is in a parallel relation with the coaxial longitudinal axes of the pipes  12  and  14 . Nuts  44   a  and  44   b  are threadably engaged with the distal and proximal ends of the tie rod  43 , respectively, thereby connecting the arcuate members  16   a  and  16   b  with the arcuate members  18   a  and  18   b.  In an identical manner, a tie rod  46  extends through each aligned bore  28   b ′ of the arcuate members  16   b  and  18   b,  and nuts  48   a  and  48   b  are threadably engaged with the distal and proximal ends of the tie rod, respectively. Similarly, tie rods  50  and  52  extend through each aligned bore  28   a ′ and  28   b ′, respectively, of the arcuate members  16   a  and  18   a  (tie rod  52  shown in  FIG. 5 ). Nuts  54   a  and  54   b  are threadably engaged with the distal and proximal ends of the tied rod  50 , respectively, and nuts  56   a  and  56   b  are threadably engaged with the distal and proximal ends of the tied rod  52 , respectively (nut  56   b  not shown). 
         [0020]    In operation, with continuing reference to  FIGS. 1-5 , the pipes  12  and  14  form a fluid-transporting pipeline so that the pipes are subject to internal hydrostatic pressure. This internal pressure, along with any external forces present due to system-level or environmental conditions, results in forces being applied to the connection between the spigot of the pipe  12  and the bell  14   a  of the pipe  14  which, in turn, urge the pipes  12  and  14  to axially separate or pull apart from each other. 
         [0021]    However, pipe-restraining assembly  10  restrains or prevents the pipe  12  from appreciably moving axially relative to, or separating from, the pipe  14 , and vice versa. The penetrating engagement of the ridges  32   a - 32   d  of the arcuate members  16   a  and  16   b  into the pipe  12  prevents the arcuate members from moving axially relative to the pipe  12 . Likewise, the penetrating engagement of the ridges  32   a - 32   d  of the arcuate members  18   a  and  18   b  into the pipe  14  prevents the arcuate members from moving axially relative to the pipe  14 . Further, the clamping forces generated by the threaded engagements of the tie rods  43 ,  46 ,  50  and  52  with the nuts  44   a  and  44   b,    48   a  and  48   b,    54   a  and  54   b,  and  56   a  and  56   b,  respectively, and applied to the corresponding lugs  28   a  and  28   b,  prevents the arcuate members  16   a  and  16   b  from moving axially relative to the arcuate members  18   a  and  18   b,  and vice versa. Since the arcuate members  16   a  and  16   b,  and  18   a  and  18   b,  are prevented from moving relative to the pipes  12  and  14 , respectively, and from moving relative to each other, the pipes  12  and  14  are therefore prevented from appreciably moving relative to and/or axially separating from one another. 
         [0022]    The sections of the ridges  32   a - 32   d  located in the portions  34   a  and  34   b  of the arcuate members  16   a  and  16   b  penetratingly engage the pipe  12  to a greater degree than the sections of the ridges  32   a - 32   d  that are located outside of the portions  34   a  and  34   b.  The aforementioned heat treatment of the portions  34   a  and  34   b  and the corresponding increase in hardness promotes the increased penetration of the ridges  32   a - 32   d  into the pipe  12  at the portions. Also, the inwardly-directed radial forces exerted on the pipe  12  by the arcuate members  16   a  and  16   b  are relatively higher at the portions  34   a  and  34   b  due to the portions&#39; proximity to the clamping forces generated by the threaded engagement of the bolts  36   a  and  36   b  with the nuts  38   a  and  38   b,  respectively, and applied to the ears  20   a  and  20   b,  respectively, thereby further promoting the increased penetration of the ridges  32   a - 32   d  into the pipe at the portions. 
         [0023]    In a like manner, the sections of the ridges  32   a - 32   d  located in the portions  34   a  and  34   b  of the arcuate members  18   a  and  18   b  penetratingly engage the pipe  14  to a greater degree than the sections of the ridges  32   a - 32   d  that are located outside of the portions  34   a  and  34   b.  Thus, the increased penetration of the ridges  32   a - 32   d  at the portions  34   a  and  34   b  further prevents the arcuate members  16   a  and  16   b,  and  18   a  and  18   b,  from moving relative to the pipes  12  and  14 , respectively, thereby further inhibiting any axial separation of the pipes. 
         [0024]    Referring to  FIG. 6 , another embodiment of a pipe-restraining assembly is generally referred to by the reference numeral  58 . The embodiment shown in  FIG. 6  is similar to the embodiment shown in  FIGS. 1-5  and contains several parts of the embodiment which are given the same reference numerals. In the embodiment of  FIG. 6 , a recess  60  is formed in the curved surface  30  and the surface defined by the chamfer  22   b  so that the recess is adjacent the horizontal surface  24   b.  A plate or insert  62  is disposed in the recess  60  and connected to the arcuate member  16   a.  A pair of protrusions or ridges  64   a  and  64   b  extend radially inward from the insert  62  so that the distal ends of the ridges  64   a  and  64   b  are radially offset from the curved surface  30 . The ridges  64   a  and  64   b  also extend along the length of the insert  62 , thereby substantially extending along a section of the length of the curved surface  30 . The arcuate member  16   a  has a substantially uniform material hardness. The insert  62  and the ridges  64   a  and  64   b  have a material hardness that is higher than the material hardness of the arcuate member  16   a.    
         [0025]    In a like manner, inserts identical to the insert  62  are disposed in recesses formed in the opposing end of the arcuate member  16   a,  and in the opposing ends of the arcuate members  16   b,    18   a  and  18   b.  It is understood that, with the exception of the foregoing, the pipe-restraining assembly  58  is identical to the pipe-restraining assembly  10  and therefore will not be further described. 
         [0026]    The operation of the embodiment of  FIG. 6  is similar to that of  FIGS. 1-5 , except that the ridges  64   a  and  64   b  extending from the insert  62 , and the ridges extending from the other inserts connected to the arcuate members  16   a,    16   b,    18   a  and  18   b,  penetratingly engage the pipes  12  and  14  to a greater degree than the ridges  32   a - 32   d  extending from the curved surfaces  30  of the arcuate members. 
       Variations 
       [0027]    It is understood that variations may be made in the foregoing without departing from the scope of the disclosure. For example, only one pair of arcuate members  16   a  and  16   b,  or  18   a  and  18   b,  may include the ridges  32   a - 32   d.    
         [0028]    Further, instead of connecting the pair of arcuate members  16   a  and  16   b  to another pair of identical arcuate members such as the arcuate members  18   a  and  18   b,  the pair of arcuate members  16   a  and  16   b  could be connected to the restrained sleeve pipe coupling and/or one or more of the corresponding end rings disclosed in co-pending patent application Ser. No. 10/170,477, published on Dec. 18, 2003 as U.S. patent application publication no. 2003/0230897 A1, the disclosure of which is incorporated by reference. 
         [0029]    Still further, the pair of arcuate members  16   a  and  16   b  could be employed in conjunction with a conventional flanged connection between a pipe having a flange and a pipe having a plain end. The arcuate members  16   a  and  16   b  could be clamped together around the pipe having the plain end in a manner described above, and the tie rods  43 ,  46 ,  50  and  52  could extend from the arcuate members  16   a  and  16   b  and through bores formed in the flange. The nuts  44   b,    48   b,    54   b  and  56   b  could then be threadably engaged with the tie rods  43 ,  46 ,  50  and  52 , respectively, to apply clamping forces to the flange and promote a flanged connection that is more resistive to any forces tending to separate the pipes. It is understood that the flanged connection may be between straight pipe sections, curved pipe sections, etc. or any combination thereof. 
         [0030]    In view of the foregoing, it is understood that the pair of arcuate members  16   a  and  16   b,  or  18   a  and  18   b,  may be clamped around any pipe in any type of application where it is desired to form a ring around the pipe and maintain the as-installed position of the arcuate members relative to the pipe, notwithstanding the subsequent subjection of the installed arcuate members, or ring, to various static and/or dynamic loads in various directions. 
         [0031]    Additional variations include the following:
       1. The quantity and spacing of the lugs  28   a  and  28   b  and any corresponding tie rods may be varied.   2. The pipes  12  and  14  may be made of other material such as, for example, high-density polyethylene. It is understood that the pipes  12  and  14  may be made of many different types of materials having widely varying material hardness levels.   3. In addition to the employment of ears, bolts and nuts, the arcuate members  16   a  and  16   b,  and  18   a  and  18   b,  may be connected using other conventional fastening means such as, for example, with clamps.   4. The number of ridges extending from the curved surface  30  and the insert  62  may be varied. Further, the size, shape, location, spacing and cross-sectional profile of the ridges  32   a - 32   d  and  64   a - 64   b  may be varied. For example, the ridges  32   a - 32   d  and  64   a - 64   b  may have rectangular, triangular or arcuate cross-sections, or any combination thereof.   5. For the embodiment of  FIGS. 1-5 , the locations and size of the portions  34   a  and  34   b  may be varied, and the quantity of the portions may be varied. For the embodiment of  FIG. 6 , the quantity, locations and size of the inserts  62  may be varied.   6. In addition to the above-described spigot-and-bell and flanged connections, the pipe-restraining assembly  10  and/or  58  and/or any variation thereof may be used with other types of pipe connections.   7. The cross-sectional profiles and the locations of the arcuate members  16   a,    16   b,    18   a  and  18   b  relative to the connection between the pipes  12  and  14  may be varied.   8. In addition to tie rods, other fastening means may be employed to connect the pair of arcuate members  16   a  and  16   b  to the pair of arcuate members  18   a  and  18   b  such as, for example, cables and turnbuckles, bolts, etc. or any combination thereof.   9. The lengths of the tie rods  43 ,  46 ,  50  and  52  and the bolts  36   a,    36   b,    40   a  and  40   b  may be varied.   10. For the embodiment of  FIG. 6 , different portions of the arcuate members  16   a,    16   b,    18   a  and  18   b  may have different material hardness levels, instead of the arcuate members having a substantially uniform hardness level.   11. For the embodiments of  FIGS. 1-5  and  FIG. 6 , different portions of the curved surfaces  30 , and the balance of the arcuate members  16   a,    16   b,    18   a  and  18   b,  may have differing material hardness levels. For example, there may be three or more material hardness levels in a single arcuate member in either embodiment.   12. The pipe-restraining assemblies  10  and  58  may be combined so that one pair of arcuate members employs the inserts  62  while the other pair of arcuate members does not.   13. Additional pairs of arcuate members may be clamped around the same or additional pipes. These additional pairs may be connected to the arcuate members  16   a  and  16   b  and/or  18   a  and  18   b.      14. The arcuate members  16   a  and  16   b  may be modified so that the surfaces  24   a  and  24   b  of each arcuate member  16   a  and  16   b  do not contact the corresponding surfaces  24   a  and  24   b,  respectively, of the other arcuate member. The arcuate members  18   a  and  18   b  may also be modified in this manner.   15. Any foregoing spatial references, such as “upper,” “lower,” “above,” “below,” “between,” “vertical,” “angular,” etc., are for the purpose of illustration only and do not limit the specific orientation or location of the structure described above.       
 
         [0047]    Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many other modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.