Abstract:
An expansion ring assembly seals a gasket with respect to an annular wall of a rigid structure. The expansion ring assembly includes two arcuate expansion ring bands that cooperate to define a generally circular profile. At one side of the expansion ring assembly, a first pair of ends of the expansion ring bands overlap and include a ratcheting mechanism which allows the ring to incrementally expand but not to contract. At another location of the expansion ring assembly, a second pair of ends are joined by a drive mechanism for engaging and driving apart the opposing ends of an expansion ring to thereby non-incrementally expand the ring. The ratchet mechanism may be used to initially set and hold the expansion ring against a gasket in a desired position and to provide an initial expansion pressure, i.e., for a coarse adjustment. The drive mechanism may then be used to provide a final expansion pressure of the gasket, i.e., for a fine adjustment. Advantageously, the coarse adjustment followed by the final adjustment allows a user to quickly and precisely achieve a desired gasket pressure by manipulating the torque applied to the drive mechanism.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under Title 35, U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/316,586, filed Mar. 23, 2010, the entire disclosure of which is hereby expressly incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to an expandable seal arrangement, and associated method, for sealing a gasket to an annular wall of a rigid structure. 
         [0004]    2. Description of the Related Art 
         [0005]    Manhole access ports are often assemblies of various components placed adjacent one another, and have joints which may also need to be sealed from leakage. For example, it may be desirable to provide a seal across a manhole frame, optionally one or more grade rings, and a manhole chimney to prevent moisture infiltration into the fluid passageway accessed by the manhole access port. 
         [0006]    In underground pipe systems, it is often necessary to connect a pipe in a sealed manner within an opening in the wall of a rigid structure, such as a manhole riser or monolithic base, for example. Typically, a flexible elastomeric gasket is placed within the opening in the wall, followed by fitting an expansion ring against the interior surface of the gasket. Thereafter, a suitable expansion mechanism is used to radially expand the expansion ring and lock same in an expanded condition in which the gasket is sealingly compressed between the expansion ring and the opening in the wall of the structure. Thereafter, a pipe is inserted through the gasket, and one or more clamps are installed around a portion of the gasket which extends from the wall to sealingly compress the extending portion of the gasket between the clamps and the outer surface of the pipe. In this manner, a sealed connection is made between the pipe and the structure. 
         [0007]    Similarly, sealed connections between two pipes are frequently made. Underground pipes which are used in municipal water and sewer systems, for example, typically include bell and spigot ends that are attached to one another in a sealed manner. Typically, either the spigot end or the bell end of such pipes includes a rubber seal which is compressed between the ends of the pipes to provide a sealed joint when the spigot end of one pipe is inserted into the bell end of another pipe. Occasionally, these primary joint seals between adjacent pipes may leak after installation in the field, requiring a secondary sealing assembly to seal the connection. 
         [0008]    Yet another application for a pipe seal is the fixing of a leak within a pipe structure. Where a pipe has begun allowing ingress of moisture, such as through a hole or crack in the wall of the pipe, a gasket may be placed within the wall of the pipe spanning the structure, and each side of the gasket may be sealed to prevent further leakage into the pipe. 
         [0009]    To make the above seals, a flexible elastomeric gasket may be placed against the pipe or manhole wall, followed by fitting an expansion ring against the interior surface of the gasket. Thereafter, a suitable expansion mechanism is used to radially expand the expansion ring and lock same in an expanded condition so that the gasket is sealingly compressed between the expansion ring and the wall of the pipe or manhole at the joint. Thereafter, a pipe is inserted through the gasket, and one or more clamps are installed around a portion of the gasket which extends from the wall to sealingly compress the extending portion of the gasket between the clamps and the outer surface of the pipe. In this manner, a sealed connection is made between the pipe and the structure. 
         [0010]    What is needed is an improved expansion ring mechanism and sealing assembly for sealing joints in fluid-carrying structures such as manhole access ports, underground pipes, and underground pipe junction points, for example. 
       SUMMARY 
       [0011]    The present disclosure provides an expansion ring assembly for sealing a gasket with respect to an annular wall of a rigid structure. The expansion ring assembly includes two arcuate expansion ring bands that cooperate to define a generally circular profile. At one side of the expansion ring assembly, a first pair of ends of the expansion ring bands overlap and include a ratcheting mechanism which allows the ring to incrementally expand but not to contract. At another location of the expansion ring assembly, a second pair of ends are joined by a drive mechanism for engaging and driving apart the opposing ends of an expansion ring to thereby non-incrementally expand the ring. The ratchet mechanism may be used to initially set and hold the expansion ring against a gasket in a desired position and to provide an initial expansion pressure, i.e., for a coarse adjustment. The drive mechanism may then be used to provide a final expansion pressure of the gasket, i.e., for a fine adjustment. Advantageously, the coarse adjustment followed by the final adjustment allows a user to quickly and precisely achieve a desired gasket pressure by manipulating the torque applied to the drive mechanism. 
         [0012]    The ratchet mechanism includes a tooth formed on the first ring band which cooperates with a series or rack of slots or apertures formed in the second, overlapping ring band, each of the apertures sized to receive the tooth therein. As the first and second ring bands are moved apart from one another to incrementally expand the overall size of the expansion ring, the tooth advances along the series of slots. Movement of the tooth in the other direction is prevented by the ratchet mechanism, so that contraction of the band is prevented from occurring once the band has been expanded. 
         [0013]    The drive mechanism generally includes a pair of block members having threaded bores therethrough, and a bolt having oppositely-threaded ends which are threaded within respective bores of the block members. The bolt additionally includes a tool-receiving structure, such as a nut portion, which may be engaged by a suitable tool to rotate the bolt. The block members are respectively engaged with opposite ends of the expansion ring. Rotation of the bolt in a first direction simultaneously drives the block members apart from one another along the bolt to radially expand the expansion ring, and rotation of the bolt in a an opposite, second direction simultaneously drives the block members toward one another along the bolt to allow the expansion ring to radially contract. 
         [0014]    Expansion of the expansion ring compresses the gasket between the expansion ring and the opening of the structure to provide a fluid tight seal between the gasket and the structure. Subsequently, a gasket may be sealed about the interface between a manhole base and a manhole frame to prevent water infiltration into a manhole. 
         [0015]    The present expansion ring assembly may also be used in other applications, such as, for example, for sealing an internal coupling gasket within one or more pipes to prevent water infiltration into a pipeline. Alternatively, a pipe may be coupled to a structure by coupling a gasket to an annular opening in the wall of a structure and inserting a pipe through a second portion of the gasket which extends outwardly of the structure, and then securing the extending portion of the gasket to the outer surface of the pipe using conventional hose clamps or take-up clamps, for example. 
         [0016]    Advantageously, the ratchet mechanism allows rapid expansion of a contracted expansion ring to a size nearly large enough to form a fluid-tight seal. An initial expansion is rapidly accomplished utilizing the ratchet mechanism. The substantial overlap of the expansion ring bands at the ratchet mechanism allow a large expansion from a contracted state, so that the expansion ring assembly may easily be placed within a manhole or pipe assembly prior to expansion. The ratcheting mechanism is then used to expand the expansion ring assembly to fit the annular surface of the manhole or pipe, with overlap remaining at the ratcheting mechanism to provide a continuous annular surface for an effective gasket seal. 
         [0017]    For the final expansion of the expansion ring, the oppositely-threaded ends of the bolt may be rotated in one direction to simultaneously drive the block members apart from each other to expand the expansion ring, such that only one tool need be used to actuate the drive mechanism to expand the expansion ring. Additionally, the screw threaded engagement between the bolt and the block members allows the block members to be driven away from one another along the bolt to an infinitely variable extent based upon the rotational position of the bolt. Therefore, after the initial rapid expansion of the ring with the ratchet mechanism, the expansion ring may be further expanded by applying a known amount of torque to the drive mechanism. A precise pressure in the expansion ring assembly is achieved, and the gasket is firmly and sufficiently compressed between the expansion ring and the opening of the structure to provide a fluid tight seal. 
         [0018]    A further advantage of the expansion ring assembly is the ability to remove the assembly from the structure if needed, followed by re-installing the assembly in a different position, or by re-using the assembly by installing same in a different structure or using same in a different application. The expansion ring may be collapsed to a contracted position by rotating the bolt of the drive mechanism in the opposite direction, and/or by disengaging the ratcheting mechanism. 
         [0019]    The disclosure, in one form thereof, comprises an expansion ring assembly for sealing a gasket against an annular surface, the expansion ring assembly, including a ring having a circumference, the ring including first and second ring band each having opposite ends, a ratcheting mechanism joining respective first ends of the ring band, the ratcheting mechanism allowing incremental expansion of the circumference of the ring by a first distance and preventing contraction of the circumference of the ring, and a drive mechanism joining respective second ends of the ring band, the drive mechanism including a pair of first threaded members joined to the respective second ends of the ring band, and a second threaded member disposed between and threadingly connecting the pair of first threaded members, the drive mechanism allowing non-incremental expansion of the circumference of the ring by a second distance to a fully expanded configuration, the drive mechanism also allowing non-incremental contraction of the circumference of the ring by a third distance, whereby the expansion ring assembly cooperates with the gasket to form a fluid type seal at the annular surface and a fully expanded configuration. 
         [0020]    The disclosure, in another form thereof, comprises an expansion ring assembly for sealing the gasket against an annular surface, the expansion ring assembly comprising a ring having a circumference, the ring including first and second ring bands each having opposite ends, means for providing incremental expansion of the circumference of the rings by a first distance, the means for providing incremental expansion preventing contraction of the circumference of the ring, and means for providing non-incremental expansion of the circumference of the ring by a second distance to a fully expanded configuration, the means for providing non-incremental expansion also allowing non-incremental contraction of the circumference of the ring by a third distance, whereby the expansion ring assembly cooperates with the gasket to form a fluid type seal at the annular surface and the fully expanded configuration. 
         [0021]    The disclosure, in a further form thereof, comprises a method of installing a gasket against annular surface, the method including placing an expansion ring assembly in a contracted configuration approximate to gasket so that gasket is disposed between the expansion ring assembly and the annular surface, actuating a first, ratcheting mechanism to incrementally expand the expansion ring assembly to a partially expanded configuration, and actuating a second mechanism having a pair of threaded members, where an actuation of the second mechanism simultaneously drives the pair of threaded members away from one another to non-incrementally expand the expansion ring assembly to a fully expanded configuration, the expansion ring assembly cooperating with the gasket to form a fluid type seal at the annular surface in the fully expanded configuration. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0023]      FIG. 1  is a perspective view of an expansion ring assembly in accordance with the present disclosure; 
           [0024]      FIG. 2  is another perspective view of the expansion ring assembly shown in  FIG. 1 ; 
           [0025]      FIG. 3  is a partial perspective view of a portion of the expansion ring assembly shown in  FIG. 2 , illustrating a ratcheting mechanism series of slots; 
           [0026]      FIG. 4  is a partial perspective view of the expansion ring assembly shown in  FIG. 1 , illustrating a ratcheting mechanism tooth; 
           [0027]      FIG. 5  is a perspective view of an expansion ring ratcheting tool usable with the ratcheting mechanism shown in  FIGS. 3 and 4 ; 
           [0028]      FIG. 6  is a partial sectional view of a connection between a concrete structure and a pipe, wherein a wall of the concrete structure includes an opening into which a gasket is sealingly fitted with an expansion ring assembly according to the present disclosure, and further showing a pipe sealingly connected to the gasket; 
           [0029]      FIG. 7  is a partial sectional view of a connection between a manhole frame and a manhole base disposed beneath a pavement surface, showing a gasket sealingly connecting the manhole base and the manhole frame using a pair of expansion ring assemblies according to the present disclosure to prevent water infiltration into the manhole; 
           [0030]      FIG. 8  is a partially exploded view of a pipe-to-pipe connection which includes an internal pipe coupler therebetween, the internal pipe coupler including a pair of expansion ring assemblies according to the present disclosure to prevent water infiltration into the pipes; 
           [0031]      FIG. 9  is an exploded, fragmentary view of the expansion ring assembly of  FIG. 1A , showing the expansion ring ends, the drive mechanism, and the oversleeve; and 
           [0032]      FIG. 10  is a fragmentary perspective view of the pipe connection of  FIG. 1A , showing the actuation of the drive mechanism to expand the expansion ring. 
       
    
    
       [0033]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the disclosure, and such exemplifications are not to be construed as limiting the scope of the invention any manner. 
       DETAILED DESCRIPTION 
       [0034]    Referring to  FIGS. 1 and 2 , expansion ring assembly  34  includes first ring band  36   a  having opposite ends  48   a , and second ring band  36   b  having opposite ends  48   b . At one side of expansion ring mechanism  34 , ends  48   a ,  48   b  of ring bands  36   a ,  36   b  are joined by drive mechanism  38 , which can be used to continuously non-incrementally expand or non-incrementally contract the overall size of expansion ring assembly  34  as discussed in detail below. At the other end of expansion ring assembly  34 , ends  48   a ,  48   b  of ring bands  36   a ,  36   b  are joined by ratchet mechanism  100 , which can be used to quickly incrementally expand expansion ring assembly  34  by discrete amounts. Ratchet mechanism  100  can be used to make a “macro” or large-scale expansion of expansion ring assembly  34 , such as upon initial installation at a manhole assembly, pipe connection, or the like. With this large scale adjustment made, drive mechanism  38  may be used to make “micro” or small-scale adjustments to either expand or contract expansion ring assembly  34  to provide a desired or appropriate amount of expansion force or pressure, such as may be required for a particular gasket arrangement. The expansion force may be inferred from the amount of torque applied to drive mechanism, so that a known torque indicates the desired amount of expansion pressure. 
         [0035]      FIG. 2  illustrates ratchet mechanism  100  joining ends  48   a ,  48   b  of ring bands  36   a ,  36   b . Ratchet mechanism  100  allows first ring band  36   a  to move relative to second ring band  36   b  in direction A. Direction A corresponds to the direction of a first distance along which ratchet mechanism  100  allows incremental expansion of the circumference of ring assembly  34 .  FIG. 2  also illustrates drive mechanism  38  joining opposite ends  48   a ,  48   b  of ring bands  36   a ,  36   b . Drive mechanism  38  allows first ring band  36   a  to move in direction B 1  and second ring band  36   b  to move in direction B 2  such that first ring band  36   a  and second ring band  36   b  simultaneously move away from one another. Direction B 1  and direction B 2  correspond to the direction of a second distance along which drive mechanism  38  allows non-incremental expansion of the circumference of ring assembly  34  to a fully expanded configuration. Drive mechanism  38  also allows first ring band  36   a  to move in direction C 1  and second ring band  36   b  to move in direction C 2  such that first ring band  36   a  and second ring band  36   b  simultaneously move toward one another. Direction C 1  and direction C 2  correspond to the direction of a third distance along which drive mechanism  38  allows non-incremental contraction of the circumference of ring assembly  34 . In one embodiment, the first distance that ratchet mechanism  100  allows incremental expansion of the circumference of ring assembly  34  is greater than the second distance that drive mechanism  38  allows non-incremental expansion of the circumference of ring assembly  34 . 
         [0036]    1. Expansion Ring Assembly Uses and Environments 
         [0037]    In use, expansion ring assembly  34  may be used to seal a gasket at a connection or junction between two or more fluid-carrying structures. For example, referring to  FIG. 6 , expansion ring assembly may be used to seal gasket  26  at pipe connection  20 . Pipe connection  20  is shown in the context of an underground pipe system, in which a pipe is connected to a structure, such as a manhole riser or monolithic base, for example. The structure may be formed of concrete, fiberglass, or any other suitable rigid material. The structure includes wall  22  having interior side  22   a  defining the interior of the structure, and exterior side  22   b  defining the exterior of the structure. Additionally, wall  22  includes opening  24  therein. An annular gasket  26  includes a first portion  28  disposed within opening  24  of wall  22 , and a second portion  30  extending from first portion  28 . Gasket  26  may be made from a flexible, elastomeric material such as rubber or neoprene, for example, and provides a sealing connection between opening  24  in wall  22  of the structure and a pipe  32 . First portion  28  of gasket  26  is sealingly engaged with opening  24  of wall  22  by expansion ring assembly  34 , which generally includes first and second expansion ring bands  36   a ,  36   b , drive mechanism  38 , oversleeve  40 , and ratchet mechanism  100 . As discussed in detail below, expansion ring assembly  34  is radially expandable to compress gasket  26  into sealing engagement with opening  24  in wall  22  to provide a fluid tight seal therebetween. 
         [0038]    After first portion  28  of gasket  26  is sealingly engaged with opening  24  of wall  22  by expansion ring assembly  34 , second portion  30  of gasket  26  is connected to pipe  32  by inserting pipe  32  therethrough, followed by installing one or more clamps  42  around second portion  30  of gasket  26  and tightening clamps  42  to compress second portion  28  of gasket  26  into sealing engagement with outer surface  44  of pipe  32  to provide a fluid tight seal therebetween. Second portion  30  of gasket  26  may include annular recessed seats  46  for receipt of clamps  42  to locate clamps  42  on second portion  30  of gasket  26 . 
         [0039]    In  FIG. 6 , only a portion of the length of pipe  32  is shown for clarity, it being understood that pipe  32  typically extends past expansion ring assembly  34  through opening  24  in wall  22 , past inner surface  22   a  of wall  22 , and into the interior of the structure. Also, expansion ring assembly  34  is shown in  FIG. 6  with drive mechanism  38  disposed in a nine o&#39;clock position with respect to opening  24  for clarity, and with ratcheting mechanism  100  not shown, it being understood that ratcheting mechanism  100  is disposed generally opposite drive mechanism  38 . However, expansion ring assembly  34  may be selectively configured with drive mechanism  38  and ratcheting mechanism  100  oriented in any desired position around the circumference of opening  24 , it being noted that a configuration with drive mechanism  38  disposed in a twelve o&#39;clock position is favored in many applications. Further, the pipe connection of  FIG. 6  may installed in a manner in which second portion  30  of gasket  26  extends inward of wall  22 , in essentially the opposite manner shown in  FIG. 6 , such that clamps  42  are disposed within the structure. 
         [0040]    Although expansion ring assembly  34  is shown in  FIG. 6  in an application in which expansion ring assembly  34  is used to seal a gasket within an opening in the wall of a structure, expansion ring assembly  34  may also be used in many other applications. For example, in  FIG. 7 , a pair of expansion ring assemblies  34   a  and  34   b  are used to seal gasket  27  about an interface between manhole base  29  and a manhole frame  31  disposed beneath pavement surface  33 . Specifically, an upper expansion ring assembly  34   a  is used to press an upper portion of gasket  27  into sealing engagement with manhole frame  31 , and a lower expansion ring assembly  34   b  is used to press a lower portion of gasket  27  into sealing engagement with manhole base  29 . In this manner, water infiltration into manhole base  29  is prevented, regardless of whether relative movement occurs between manhole frame  31  and manhole base  29 . 
         [0041]    In  FIG. 8 , a pair of expansion ring assemblies  34   a  and  34   b  are used with an internal coupling gasket  35  for sealing a connection between the female or bell end  37  of a first pipe  32   a  and the male or spigot end  39  of a second pipe  32   b . Specifically, a first expansion ring mechanism  34   a  presses one end of gasket  35  into sealing engagement with bell end  37  of pipe  32   a , and a second expansion ring assembly presses an opposite end of gasket  35  into sealing engagement with spigot end  39  of pipe  32   b  to prevent water infiltration into the pipes if or when the primary bell-spigot connection between pipes  32   a  and  32   b  fails. Alternatively, expansion ring assemblies  34   a  and  34   b  may be used with an internal coupling gasket  35  to bridge and seal a crack or leak disposed anywhere along a single pipe  32  within a pipeline. 
         [0042]    Thus, expansion ring assembly  34  may be used in any application which generally involves the radial expansion of a flexible gasket into sealing engagement with a rigid structure. The details and operation of expansion ring assembly  34  are discussed below. 
         [0043]    2. Expansion Ring Construction 
         [0044]    Referring to  FIGS. 1 ,  2  and  9 , a first embodiment of expansion ring assembly  34  is shown. Expansion ring bands  36   a ,  36   b  are made of a continuous strip of material, such as stainless steel, other metals, or a plastic, for example, and include opposite ends  48   a ,  48   b , respectively. Expansion ring bands  36   a ,  36   b  may include a generally planar base wall  50  ( FIG. 9 ) having outer surface  52  for engaging the interior surface of a gasket. Expansion ring bands  36   a ,  36   b  may form substantially flat annular surfaces, as shown in  FIGS. 1-4 ,  6 ,  7  and  10 , or may have side walls  54  projecting inwardly from base wall  50 , as shown in  FIG. 9 . Where bands  36   a ,  36   b  have side walls,  54 , base wall  50  and side walls  54  together define a generally U-shaped cross-sectional profile; however, the overall shape of expansion ring bands  36   a ,  36   b  may vary. As shown in  FIG. 9 , ends  48   a ,  48   b  of expansion ring bands  36   a ,  36   b  may also include optional crimped portions  56 . Side walls  54  and/or crimped portions  56  may be provided at either end of bands  36   a ,  36   b , i.e., side walls  54  and crimped portions  56  may cooperate with either drive mechanism  38  or ratchet mechanism  100 , or both. 
         [0045]    In the illustrated embodiment, expansion ring bands  36   a ,  36   b  each span about half of the overall circumferential extent of expansion ring assembly  34 . However, it is within the scope of the present disclosure that expansion ring bands  36   a ,  36   b  may not be equal in length. In addition, more than two expansion ring bands may be used to form expansion ring assembly  34 , with drive mechanism  38  and/or ratchet mechanism  100  disposed at the junction between each respective ring band. 
         [0046]    Turning now to  FIGS. 3 and 4 , ratchet mechanism  100  includes pawl or tooth  102  formed in second ring band  36   b  and a series or rack  104  of apertures or slots  106  formed in first ring band  36   a . In the illustrated embodiment, tooth  102  is integral with second ring band  36   b , and may be formed by punching tooth  102  out of the material of band  36   b . Tooth  102  is therefore an inwardly extending portion of second ring band  36   b , and is directed towards the center of expansion ring assembly  34 . Tooth  102  forms angle θ with a tangent plane contacting tooth  102 . Angle θ is sufficiently small to allow rack  104  to slide freely in an expanding direction, while being prevented from moving in a contracting direction, as discussed in detail below. 
         [0047]    As best seen in  FIG. 3 , rack  104  includes a plurality of apertures  106  sized to receive tooth  102  therein. Apertures  106  are successively arranged along one of ends  48   a  of first ring band  36   a  with spacing or pitch P between respective pairs of apertures  106 . Pitch P determines the resolution of adjustment of expansion ring assembly  34  using rack  100 . That is to say, as expansion ring assembly  34  is incrementally expanded by advancing tooth  102  from any of apertures  106  to the next neighboring aperture  106  in the direction of end  48   a  of first ring band  36   a , the overall increase in the circumference of expansion ring assembly  34  will be equal to pitch P. Similarly, if the circumference of expansion ring assembly  34  is constrained from expanding by an amount equaling at least pitch P (such as by contact with wall  22  via gasket  26 , as discussed above), tooth  102  will not be able to advance to the next neighboring aperture  106  of rack  104 . As described in detail herein, drive mechanism may then be used for final non-incremental expansion of expansion ring assembly  34 . Thus, ratchet mechanism  100  provides a large-scale or macro adjustment in that expansion ring assembly  34  may only be adjusted using rack  104  by increments of pitch P. On the other hand, drive mechanism  38  ( FIGS. 1 ,  9  and  10 ) may be used to continuously adjust the size of expansion ring assembly  34  by any amount, to allow precise control over the pressure exerted by expansion ring assembly  34  upon a gasket. 
         [0048]    Referring now to  FIGS. 3 and 4 , end  48   b  of expansion ring band  36   b  substantially overlaps end  48   a  of expansion ring band  36   a  at ratcheting mechanism  100 . This overlap is the result of expansion ring band  36   b  extending past tooth  102  by a substantial amount, as seen in  FIG. 4 . Moreover, expansion ring band  36   b  extends past tooth  102  sufficiently far to ensure overlap between expansion ring bands  36   a ,  36   b  at ratcheting mechanism  100  even when tooth  102  is engaged with the aperture  106  closest to end  48   a  of expansion ring band  36   a . Advantageously, this overlap produces a substantially continuous annular surface at the outside of expansion ring assembly  34 , which facilitates proper and continuous sealing pressure against an adjacent structure such as gasket  26 . This continuous pressure ensures a fluid-tight seal across the entire extent of ratcheting mechanism  100 , and throughout the entire range of motion of same, as described in detail below. 
         [0049]    As best seen in  FIGS. 9 and 10 , drive mechanism  38  generally includes a pair of first threaded members, such as a pair of block members  58 , and a second threaded member, such as bolt  60 , disposed between and threadingly connecting block members  58 . Block members  58  each include threaded bore  62  and a pair of shoulders  64  on opposite sides thereof. The bores  62  of a pair of block members  58  of each drive mechanism  38  are oppositely threaded, for reasons discussed below. Block members  58  are removably attached to respective ends  48   a ,  48   b  of expansion ring bands  36   a ,  36   b  by sliding shoulders  64  within crimped portions  56  of a pair of ends  48   a ,  48   b  of expansion ring bands  36   a ,  36   b  until front edges  66  thereof abut ledges  68  of block members  58 . The foregoing connection configuration between block members  58  and ends  48   a ,  48   b  of expansion ring bands  36   a ,  36   b  is exemplary, it being understood that many other types of configurations for removably connecting block members  58  to ends  48   a ,  48   b  may be devised. For example, it is within the scope of the present disclosure that block members  58  may have an external thread rather than an internal thread, and that bolt  60  may have internal threads adapted to cooperate with the external threads of block members  58 . Block members  58  may also be removably attachable to respective ends  48   a ,  48   b  of expansion ring bands  36   a ,  36   b  by any connection configuration in accordance with the connection configurations between block members and end portions of expansion ring bands described in U.S. Pat. No. 7,146,689, issued Dec. 12, 2006, entitled “Expansion Ring Assembly,” the entire disclosure of which is hereby expressly incorporated herein by reference. 
         [0050]    Bolt  60  includes oppositely-threaded ends  70   a  and  70   b ; for example, end  70   a  has right-hand threads and end  70   b  has left-hand threads, or vice-versa. Bolt  60  additionally includes a suitable tool-receiving structure between bolt ends  70   a  and  70   b , such as hexagonal nut portion  72  integrally formed with bolt  60 . Although nut portion  72  is shown herein as having a hexagonal configuration, i.e., having six sides, other shapes for nut portion are possible, wherein nut portion may have four, five, six, or more sides, for example. Bolt ends  70   a  and  70   b  are threadingly engaged within the corresponding threaded bores  62  of block members  58  to connect block members  58  to bolt  60 . 
         [0051]    Oversleeve  40  is formed of a segmented strip of material, such as stainless steel, other metals, or a plastic. Similar to expansion ring bands  36   a ,  36   b , oversleeve  40  includes base wall  74  and a pair of side walls  76  extending therefrom to define a U-shaped cross-sectional profile complementary to that of expansion ring bands  36   a ,  36   b , as described above. The distance between side walls  76  of oversleeve  40  is slightly wider than the corresponding distance between side walls  54  of expansion ring bands  36   a ,  36   b , such that ends of  48   a ,  48   b  thereof may nest within oversleeve  40  between side walls  76  of oversleeve  40 , as shown in  FIG. 10 . 
         [0052]    3. Operation of the Expansion Band 
         [0053]    As a first step, expansion band assembly  34  is placed at the site of installation, such as adjacent gasket  26  at wall  22 , or adjacent gasket  35  at the junction between two pipes  32   a ,  32   b , for example, as described above. Expansion band assembly  34  is in a contracted or partially contracted state upon being so placed, so that expansion band assembly  34  may be easily maneuvered into a proper position and orientation. Once in the proper position, ratcheting mechanism  100  may be actuated by simply pulling expansion rings bands  36   a ,  36   b  apart from one another by hand, thereby drawing tooth  102  over one or more apertures  106  of rack  104 . With the initial expansion complete, ratcheting mechanism may optionally be expanded further using ratchet tool  110 . 
         [0054]    Turning now to  FIG. 5 , ratchet tool  110  may be provided to actuate ratchet mechanism  100 . Ratchet tool  110  includes first engagement shaft  112  which is rigidly connected to handle  114 . Second engagement shaft  116  is pivotally connected to first engagement shaft  112  at pivot  118 . First engagement shaft  112  includes a generally cylindrical engagement end  120  sized to be received within a tool engagement structure such as tool aperture or hole  108   a  formed in first ring band  36   a  ( FIGS. 2 and 3 ). Alternatively, engagement end  120  of shaft  112  may be shaped to fit within one of apertures  106 , obviating the need for aperture  108   a  or allowing aperture  108   a  to be formed as one of apertures  106  in rack  104 . Second engagement shaft  116  includes second engagement end  122  sized to be received within another tool engagement structure such as any of a plurality of tool apertures  108   b  formed in second ring band  36   b  ( FIGS. 1 ,  2  and  4 ). Referring to  FIG. 3 , tool aperture  108   a  is spaced from and separate from apertures  106 . Second engagement end  122  may include transverse pin  124  to control the depth of engagement of second engagement end  122  within tool apertures  108   b . Second engagement shaft  116  further includes bend  126  to orient second engagement end  122  to face tool apertures  108   b.    
         [0055]    In use, ratchet tool  110  may be used to provide an expanding force to expansion ring assembly  34  at ratchet mechanism  100 . First engagement end  120  of first shaft  112  is engaged with tool aperture  108   a  of first ring band  36   a . One of tool apertures  108   b  is selected for engagement with second engagement end  122  of second shaft  116 , depending on the relative position of tooth  102  with respect to rack  104 . Once first and second engagement ends  120 ,  122  are engaged with tool apertures  108   a ,  108   b , force F is applied to handle  114  in the direction of second shaft  116 . Force F urges the expansion of expansion ring assembly  104  by forcing apertures  108   a ,  108   b  apart. Second shaft  116  pivots with respect to first shaft  112  about pivot  118 , allowing first and second engagement ends  120 ,  122  to move apart from one another as expansion ring assembly  34  expands. Advantageously, ratchet tool  110  allows the use of ratchet mechanism  100  to incrementally expand expansion ring assembly  34  against gasket  26 , thereby aiding in the formation of a fluid tight seal and minimizing any further adjustment needed with drive mechanism  38 . Once ratchet mechanism  100  has been fully expanded using ratchet tool  110 , drive mechanism  38  may be used for final adjustment in the expansion or contraction of expansion ring assembly  34  to achieve a precise pressure upon a gasket, as described in detail below. 
         [0056]    To actuate drive mechanism  38 , a suitable tool, such as an open-end wrench or a torque wrench, for example, is engaged with nut portion  72  of bolt  60  and used to rotate bolt  60  in a first direction as illustrated by arrow  78  (shown in  FIG. 10 ). Upon rotation of bolt  60 , the threaded engagement between bolt ends  70   a  and  70   b  and threaded bores  62  of block members  58  drives block members  58  simultaneously away from one another along bolt  60 , thereby forcing a pair of ends  48   a ,  48   b  of expansion ring bands  36   a ,  36   b  apart from one another to non-incrementally expand the diameter of expansion ring assembly  34 . During such expansion, oversleeve  40  prevents relative lateral movement between ends  48   a ,  48   b  of expansion ring bands  36   a ,  36   b  at drive mechanism  38 , such that ends  48   a ,  48   b  are constrained to move apart from one another only along the direction indicated by arrow  80 . 
         [0057]    Referring generally to  FIGS. 1-3  and  10 , gasket  26  is shown disposed within opening  24  in wall  22 , and expansion ring assembly  34  is shown fitted within the interior of gasket  26 . At one side of expansion ring assembly  34 , ratchet mechanism  100  is provided to allow a rapid, large-scale adjustment of the circumference of expansion ring assembly by allowing apertures  106  of rack  104  to slide freely over tooth  102  as expansion rings bands  36   a ,  36   b  are moved relative to one another in an expanding motion. At another side of expansion ring assembly  34 , block members  58  of drive mechanism  38  are received within a pair of respective ends  48   a ,  48   b  of expansion ring bands  36   a ,  36   b , and this pair of ends  48   a ,  48   b  are nested within oversleeve  40 , which overlaps ends  48   a ,  48   b  and spans the gap therebetween which is bridged by drive mechanism  38 . Drive mechanism  38  is oriented such that bolt  60  is disposed perpendicular to longitudinal axis L 1 -L 1 ( FIGS. 6 and 10 ) which axis is common to expansion ring assembly  34 , gasket  26 , and opening  24 . 
         [0058]    The expansion of expansion ring assembly  34  compresses gasket  26  between expansion ring bands  36   a ,  36   b  and opening  24  in wall  22  to provide a fluid tight seal between gasket  26  and wall  22 . Bolt  60  may also be rotated in a second direction opposite the first direction along arrow  78  if needed, which simultaneously drives block members  58  toward one another along bolt  60 , thereby allowing expansion ring assembly  34  to contract. In this manner, expansion ring assembly  34  may be removed after installation if necessary, in order to reposition expansion ring assembly  34  or alternatively, to re-use expansion ring assembly  34  in another installation or application. For example, ring assembly  34  can be repositioned proximate another gasket and then ratcheting mechanism  100  and drive mechanism  38  can be actuated in the manner described above to expand ring assembly  34  such that ring assembly  34  cooperates with the other gasket to form a fluid tight seal. 
         [0059]    Advantageously, the threaded engagement between the oppositely-threaded ends  70   a  and  70   b  of bolt  60  and block members  58  simultaneously drives block members  58  apart from one another along bolt  60  such that only a single tool need be used to actuate drive mechanism  38 . A single turn of a wrench, for example, drives both block members  58  apart from one another simultaneously, such that block members  58  need not be separately adjusted. Thus, the simultaneous use of multiple wrenches, as well as multiple manual adjustment steps, is avoided. Additionally, the threaded engagement between bolt ends  70   a  and  70   b  and block members  58  allows an infinitely variable degree of adjustment of drive mechanism  38 , such that expansion ring assembly  34  may be selectively expanded to any desired extent. In this manner, expansion ring assembly  34  can accommodate gaskets  26  of varying nominal sizes, and further, can also accommodate irregularities or size variations between gaskets  26  of the same nominal size. 
         [0060]    Also advantageously, the combination of ratcheting mechanism  100  with drive mechanism  38  in a single expansion ring assembly  34  facilitates a rapid and precise installation by a single installer. Ratcheting mechanism may be used for large-scale adjustments, and may be placed within an opening to be sealed by a single person by manually expanding the band to roughly fit the required aperture size. With the installer&#39;s hands freed and the gasket (i.e., gasket  26  or  35 , for example) held in place, the installer can use ratchet tool  110  to further expand expansion ring assembly  34 , and finally, can use another tool to actuate drive mechanism  38  for fine adjustments, to quickly create a final and precise seal. In the exemplary embodiment shown in the figures, the final adjustment may be used to impart a specific, precise and known pressure upon a gasket by applying a specific, known torque to bolt  60  of drive mechanism  38 . Because the pressure exerted by expansion ring assembly directly correlates to the torque applied to bolt  60 , the pressure exerted upon the gasket may be inferred by the torque applied. In this way, drive mechanism  38  allows a highly precise adjustment in conjunction with the rapid expansion afforded by ratcheting mechanism  100 . 
         [0061]    Yet another advantage of expansion ring assembly  34  is that, in the collapsed state, expansion ring assembly may be made small enough to fit easily within an installation space such as a manhole or pipe assembly. For example, the substantial overlap of expansion ring bands  36   a ,  36   b  allows expansion ring assembly  34  to be collapsed to a substantially smaller overall circumference as compared with the fully expanded circumference of expansion ring assembly  34 . Still further, this overlap cooperates with oversleeve  40  to ensure that, even when expansion ring assembly  34  is in a fully expanded condition, the outer or sealing surface of expansion ring assembly  34  defines a continuous annular surface that evenly distributes the sealing pressure against a gasket (such as, for example, gaskets  26  or  35 ). As best seen in  FIG. 4 , step  101  presents only a minimal interruption in the continuity of the outer surface, with such disruption easily absorbed by a typical gasket. 
         [0062]    While this invention has been described as having exemplary designs, the present disclosure can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which falls within the limits of the appended claims.