Abstract:
A device includes a first body having a curved wall with a top surface that slopes away from the first body and a second body having an interior configured to receive the curved wall of the first body, the interior including a curved ramp with a sloped bottom ramp surface. The second body is mounted on the first body with the bottom surface of the curved ramp resting on the top surface of the curved wall. A compressible seal extends from the first body bottom, and a shaft projects from the second body through a passage in the first body and into the interior of the compressible seal. Rotating the bodies relative to each other causes the shaft to pull the seal against the first body and radially expand the seal against an interior wall of an opening in which the device is placed to form a seal therewith.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention is directed to a device for at least partially blocking an opening and for forming a seal inside the opening, and, more specifically, toward an adapter having first and second mutually rotatable parts, a compressible seal and a shaft that extends into the compressible seal, which rotatable parts are configured to selectively compress the compressible seal toward the first and second parts to radially expand the compressible seal against an interior wall of an opening to form a seal. 
       BACKGROUND OF THE INVENTION 
       [0002]    It is often desirable to form a seal with an inside wall of an opening or a tube. This may be done to completely block or plug the opening or tube or to connect an adapter or similar structure to the opening or tube. For example, one method of filling a vehicle radiator requires establishing a partial vacuum in the radiator. This is done by inserting an adapter into the radiator filler neck, forming a seal between the adapter and the inside wall of the filler neck and using a pump to remove air from the radiator through the adapter. An opening in the adapter is then connected to a source of clean radiator fluid, and the pressure difference between the inside of the radiator and ambient pressure forces the clean radiator fluid into the radiator. 
         [0003]    Conventional adapters for filling vehicle radiators generally include a flexible seal member that is insertable into the radiator filler neck, a shaft that extends through the flexible seal member, and two bodies at one end of the seal member that are connected to one another by screwthreads. The shaft is connected to one of the bodies, extends through the other body and the seal member and is connected to the seal member. Starting with the two bodies screwed together, the flexible seal member is inserted into the filler neck, and the bodies are then screwed apart from one another. This moves the top of one body away from the bottom of the other body, pulls the distal end of the shaft toward the bodies and compresses the seal member. Such compression of the seal member causes the side wall of the seal member to bulge and press against the inside wall of the tube. As the bodies are unscrewed further, the connection between the sidewall and the seal member becomes tighter, and a fluid-tight seal with the tube sidewall is formed. 
         [0004]    This arrangement works adequately for its intended purpose. However, in order to expand the seal member sufficiently to form a tight seal with the inside wall of the filler neck, it is generally necessary to turn the one body multiple times in one direction with respect to the other body to form the seal and then to turn the one body multiple times in the other direction to reverse this process. It would be desirable to provide a device that forms a seal with the inside of an opening or tube in a manner that does not require this screwing operation and that can be sealed to and unsealed from the interior of an opening or a tube in a simple manner. 
       SUMMARY OF THE INVENTION 
       [0005]    These problems and others are addressed by embodiments of the present invention, a first aspect of which comprises an adapter that includes a first body having a bottom and a second body having a top. The second body is rotatably mounted to the first body, and the first body and the second body are movable between a first angular relationship and a second angular relationship. A first one of the first body and the second body has a first ramp with a first ramp surface, and the other one of the first body and the second body has a ramp follower in contact with the first ramp surface. The first body bottom is separated from the second body top by a first distance when the first body and second body are in the first angular relationship and by a second distance greater than the first distance when the first body and the second body are in the second angular relationship. The ramp follower moves from a first location on the first ramp surface to a second location on the first ramp surface in response to the first body and the second body moving from the first angular relationship to the second angular relationship. A compressible seal extends from the first body and has a first end at the first body, a second end spaced from the first body, an interior, and an outer wall. The outer wall is configured to form a fluid-tight seal with an interior of an opening in which the adapter is placed. A shaft projects from the second body through an opening in the first body and into the interior of the compressible seal, and the shaft is configured to move relative to the first body when the first body and the second body move from the first angular relationship to the second angular relationship. The shaft is also configured to move the second end of the compressible seal toward the first body and to radially expand the compressible seal against the interior of the opening when the first body and the second body move from the first angular relationship to the second angular relationship. 
         [0006]    A further aspect of the invention comprises a device for at least partially blocking an opening. The device includes a first body having a bottom and a second body having a top that is rotatably mounted to the first body. The first body and the second body are movable between a first angular relationship and a second angular relationship. A first one of the first body and the second body has a first ramp with a ramp surface, and a second one of the first body and the second body has a ramp follower that is in contact with the first ramp surface. The first body bottom is separated from the second body top by a first distance when the first body and the second body are in the first angular relationship and by a second distance greater than the first distance when the first body and the second body are in the second angular relationship. The ramp follower moves from a first location on the first ramp surface to a second location on the first ramp surface in response to the first body and the second body moving from the first angular relationship to the second angular relationship. A compressible seal extends from the first body and has a first end at the first body and a second end spaced from the first body and an interior. A shaft projects from the second body through an opening in the first body and into the interior of the compressible seal, and the shaft is configured to move relative to the first body when the first body and the second body move from the first angular relationship to the second angular relationship. The shaft is configured to move the second end of the compressible seal toward the first body and compress the compressible seal when the first body and the second body move from the first angular relationship to the second angular relationship. 
         [0007]    Another aspect of the invention comprises a device for at least partially blocking an opening that includes a first body having a bottom, a top and a curved wall projecting from the top. The curved wall has a first end and a second end, and at least one curved sidewall, and follows a periphery of the first body. The curved wall also has a wall top surface spaced from the top by a first distance which distance increases from the first end of the curved wall to the second end of the curved wall. The device also includes a second body having an open bottom, a top and an interior configured to receive the curved wall of the first body. The interior of the second body includes a curved ramp having a first end and a second end and a bottom surface, and the bottom surface is spaced from the second body top by a second distance which distance increases from the first end of the second ramp to the second end of the second ramp. The second body is mounted on the first body with the bottom surface of the curved ramp resting on the top surface of the curved wall. A compressible seal extends from the first body bottom and has a first end at the first body and a second end spaced from the first body and an interior. A shaft projects from the second body through an opening in the first body and into the interior of the compressible seal. 
         [0008]    A further aspect of the invention comprises a device for at least partially blocking an opening which device includes a first body having a bottom and a second body having a top that is mounted to the first body such that the first body and the second body are mutually rotatable between a first angular relationship and a second angular relationship. The first body bottom is separated from the second body top by a first distance when the first body and second body are in the first angular relationship and by a second distance greater than the first distance when the first body and the second body are in the second angular relationship. The device includes a compressible seal extending from the second body that has a first end at the second body and a second end spaced from the second body and an interior. A shaft projects from the first body through an opening in the second body and into the interior, and the shaft is configured to move relative to the second body when the first body and the second body move from the first angular relationship to the second angular relationship and is configured to move the second end of the compressible seal toward the second body and compress the compressible seal when the first body and the second body move from the first angular relationship to the second angular relationship. The device also includes means for moving the second body top away from the first body bottom in response to the rotation of the first body and the second body from the first angular relationship to the second angular relationship. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    These and other aspects and features of the present invention will be better understood after a reading of the following detailed description together with the attached drawings, wherein: 
           [0010]      FIG. 1  is a perspective view of an adapter according to an embodiment of the present invention that includes two mutually rotatable bodies and a seal that has a cone-shaped portion and a cylindrical portion. 
           [0011]      FIG. 2  is a sectional side elevational view taken along line II-II of  FIG. 1 . 
           [0012]      FIG. 3  is a first exploded perspective view of the two mutually rotatable bodies of  FIG. 1 . 
           [0013]      FIG. 4  is a second exploded perspective view of the mutually rotatable bodies of  FIG. 1 . 
           [0014]      FIG. 5  is a sectional side elevational view of a portion of the adapter of  FIG. 1  showing a first configuration of the adapter. 
           [0015]      FIG. 6  is sectional side elevational view of a portion of the adapter of  FIG. 1  showing a second configuration of the adapter. 
           [0016]      FIG. 7  is a sectional side elevational view of the adapter of  FIG. 1  with the cylindrical portion of the seal inserted into a small tube and forming a seal with the interior of the small tube. 
           [0017]      FIG. 8  is a sectional side elevational view of the adapter of  FIG. 1  with the tapered or cone-shaped portion of the seal inserted into a large tube and forming a seal with the interior of the large tube. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Referring now to the drawings, wherein the showings are for purposes of illustrating presently preferred embodiments of the invention only and not for the purpose of limiting same,  FIG. 1  illustrates an adapter  10  that includes a first body  12  having a bottom  14  and a top  16 , a second body  18  mounted on the first body  12  and having a bottom  20  and a top  22 , and a seal  24  depending from the bottom  14  of the first body  12 . The seal  24  includes a first portion  26  that is tapered and shaped like a truncated cone and a second portion  28  that is generally cylindrical. A hollow shaft  30  extends through the second body  18 , the first body  12  and the seal  24 . 
         [0019]    This embodiment comprises an adapter  10  that allows a connection to be made between a hose (not illustrated) external to the adapter  10  and a filler neck, such as one of the filler necks  146 ,  148  of  FIGS. 7 and 8 , through the hollow shaft  30 . A substantially similar device could be used as a stop or a plug for a tube if the shaft  30  were blocked or if a non-hollow shaft were used in place of the hollow shaft  30 . The present embodiment is directed primarily to an adapter  10 , but a device for forming a seal with an interior wall of an opening or a tube that does not include a hollow shaft and that does not adapt one element to another but instead serves solely as a closure or plug is also within the scope of the present invention. Moreover, while the disclosed embodiment is intended for use in a tubular filler neck of a radiator, it could also be used as a plug and/or an adapter in a passageway or opening in another structure, whether or not that structure comprises a tube. 
         [0020]    The elements of the embodiments of the present invention many be described in terms of their orientation in the figures. An element that is located above another element in the figures, may, for example, be referred to a “top” or “upper” element while an element located below that element in the figures may be referred to as a “bottom” or “lower” element. It should be understood, however, that the device described herein can be used in any orientation, and in some orientations the element referred to as a “top” element may actually be located below a “bottom” element. This is done for convenience of explanation and is not intended to limit the disclosed device to use in any particular orientation. 
         [0021]    The first body  12  includes a generally cylindrical outer wall  32  having indentations  34  and textured portions  36  that allow it to be securely grasped or turned by a user. The outer wall  32  at the bottom  14  of the first body  12  has a bottom edge  38  that defines a periphery of the first body  12  and a bottom entry into the interior  40  of the first body  12 . As illustrated in  FIG. 2 , the interior  40  includes a depending wall  42  depending from an upper portion of the first body  12  and connected to the outer wall  32  by a plurality of ribs  44 , illustrated in  FIG. 4 , the depending wall  44  defining a central chamber  46  having a top  48  in the first body  12 . A passage  49  extends through the top  48 . Each of the ribs  44  includes a cutout  45  adjacent the depending wall  42  for receiving the seal  24  as described below. 
         [0022]    Referring now to  FIGS. 3 and 4 , a first curved wall  50  extends from the top  16  of the first body  12  and includes a first end  52 , a second end  54 , a top surface or ramp surface  56 , first and second spaced, curved, sidewalls  58  and an end wall  60 . The ramp surface  56  has first and second helical side edges  62  and an end edge  64  separating the top surface  56  from the end wall  60 . A second curved wall  66  extends from the top  16  of the first body  12  inside the first curved wall  50  and includes a first end  68  a second end  70  a top or ramp surface  72 , first and second spaced, curved sidewalls  74  and an end wall  76 . The ramp surface  72  of the second curved wall  66  has first and second helical side edges  78  and an end edge  80  separating the top surface  72  of the second curved wall  66  from the end wall  76  of the second curved wall  66 . 
         [0023]    The second body  18  includes a generally cylindrical outer wall  82  having indentations  84  and textured portions  86  similar to those of the first body  12  that allow the second body  18  to be securely grasped or turned. The bottom  20  of the second body  18  includes a peripheral edge  88  that defines an opening into an interior  90  of the second body  18 . The interior  90  of the second body  18  includes a first ramp  92  having a first end  94 , a second end  96 , a bottom surface or ramp surface  98  and an end wall  100 . The interior  90  of the second body  18  also includes a second ramp  102  having a first end  104 , a second end  106 , a bottom or ramp surface  108  and an end wall  110 . The first and second ramps  92 ,  102  surround a central passage  112  in the second body  18  and a bore  114  in the top  22  of the second body  18 . The top  22  of the second body includes a flat central portion  116  surrounding the bore  114  which flat central portion  116  is surrounded by a low wall  118 . 
         [0024]    With reference to  FIG. 2 , the first portion  26  of the seal  24  is a hollow, truncated cone that has a large end  120 , a small end  122  and a hollow interior  123 . (The first portion  26  could, alternately, have a stepped configuration and “taper” in steps rather than continuously.) The large end  120  is mounted at the bottom  14  of the first body  12  around the opening into the central chamber  46  of the first body  12  and in the cutouts  45  of the ribs  44 . The cutouts  45  in the ribs  44  limit lateral movement of the first portion  26  of the seal  24  even when the seal  24  is compressed as described below. A spacer  124  is mounted at the small end  122  of the seal first portion  26 , which spacer  124  may comprise a washer, formed of metal or another material. The spacer  124  includes a first face  126  abutting the small end  122  of the seal first portion  26 , a second face  128  opposite the first face, an outer diameter approximately the same as the outer diameter of the small end  122  of the seal first portion  26  and a central opening  130  having a diameter. The second portion  28  of the seal  24  is cylindrical and has a first end  132  abutting the second face  128  of the spacer  124 , a hollow interior  134  and a second end  136  spaced from the spacer  124 . Alternately, the second portion  28  of the seal  24  could be tapered. 
         [0025]    The seal  24  is held against the bottom  14  of the first body  12  by the hollow shaft  30  that extends through the first and second bodies  12 ,  18 , and through the first and second seal members  26 ,  28  and the spacer  124 . The hollow shaft  30  has a first end portion  138  ( FIG. 1 ) that projects away from the flat central portion  116  of the second body top  22 . From the second body  18 , the hollow shaft  30  extends through the bore  114  in the second body top  22 , and through the central passage  112  inside the first ramp  92  and the second ramp  102 . The hollow shaft  30  is secured to the bore  114  in a suitable manner, such as by adhesive (not shown) and/or a suitable interlocking fit (not shown), and/or in the manner described below, against rotation relative to the second body  18  so that the hollow shaft  30  rotates with the rotation of the second body  18 . From the second body  18 , the hollow shaft  30  extends through the passage  49  in the top  16  of the first body  12 , through the central chamber  46  and past the bottom  14  of the first body  12 , and through the interior  123  of the seal first portion  26 , through the central opening  130  of the spacer  124  and through the hollow interior  134  of the seal second portion  28 . The hollow shaft  30  has a second end  139  that is terminated with a flange  140 , which flange  140  abuts the second end  136  of the seal second portion  28 . The second end  139  of the hollow shaft  30 , located between the flange  140  and the spacer  124 , has a diameter greater than the width of the central opening  130  in the spacer  124  for reasons discussed below. 
         [0026]    As illustrated in  FIGS. 5 and 6 , the hollow shaft  30  also has a first disk  142  projecting perpendicularly therefrom and securely fastened thereto and mounted on the flat central portion  116  of the top  22  of the second body  18  in the space defined by the low wall  118 . A secure connection between the first disk  142  and the top  22  of the second body  18  secures the hollow shaft  30  to the second body  18  and allows the hollow shaft  30  to rotate with the second body  18 . The relatively large surface area of the first disk  142  provides a larger area for forming a bond with the second body  18  than the area at which the hollow shaft  30  contacts the interior of the bore  114  in the top  22  of the second body  18 . Of course, the hollow shaft  30  can also be secured to the bore  114  by additional adhesive or with a mechanical interlocking arrangement as mentioned above. The hollow shaft  30  has a second disk  144  projecting perpendicularly therefrom at a location on the shaft that is inside the central chamber  46  of the first body  12 . The second disk  144  limits the upward movement of the hollow shaft  30  relative to the first body  12  because the second disk  144  cannot move past the top  48  of the central chamber  46  when the hollow shaft  30  slides through the passage  49 . 
         [0027]    The adapter  10  has a storage or nonuse configuration, illustrated in  FIG. 5 , in which the second body  18  is mounted on the first body  12  so that the bottom surface  98  of the second body first ramp  92  rests on the top surface  56  of the first curved wall  50  and so that the bottom surface  108  of the second ramp  102  rests on the top surface  72  of the second curved wall  66  with the spaced curved sidewalls  58  of the first curved wall  50  projecting at least partially into the interior  90  of the second body  18 . In this configuration, the end wall  100  of the second body first ramp  92  abuts the end wall  60  of the first curved wall  50  of the first body  12 , and the end wall  110  of the second ramp  102  abuts the end wall  76  of the second curved wall  66  of the first body  12 , and these abutting end walls limit relative rotation between the first body  12  and the second body  18  in a first direction. In this configuration, the second disk  144  is located in the central chamber  46  of the first body  12  at a distance from the top  48  of the central chamber  46 , and the flange  140  of the hollow shaft  30  holds the seal first portion  26  and the seal second portion  28  securely against the bottom  14  of the first body  12 . The length of the hollow shaft  30  is selected such that in this configuration, the seal  24  is maintained under sufficient compression to hold the seal first portion  26  and seal second portion  28  in place, but without substantially deforming either of the first and second seal portions  26 ,  28 . 
         [0028]    Rotating the second body  18  relative to the first body  12  moves the end wall  100  of the second body first ramp  92  away from the end wall  60  of the first curved wall  50  of the first body  12  and causes the bottom surface  98  of the first ramp  92  to slide over the top surface  56  of the first curved wall  50  and the bottom surface  108  of the second ramp  102  to slide over the top surface  72  of the second curved wall  66  of the first body  12 . Because the first curved wall  50  becomes taller between its first end  52  and second end  54 , the helical top surface  56  becomes increasingly distant from the top  16  of the first body between the first end  52  and the second end  54 . Preferably, the height of the first wall, namely, the distance between the top surface  56  and the top  16  of the first body  12  increases at a substantially constant rate from the first end  52  of the first curved wall  50  to the second end  54  of the first curved wall  50 . Similarly, the second curved wall  66  becomes taller between its first end  68  and its second end  70 . The distance between the bottom surface  98  of the first ramp  92  and the top  22  of the second body  18  also increases between the first end  94  and second end  96  of the first ramp, and the distance between the bottom surface  108  of the second ramp  102  and the top  22  of the second body  18  also increases between the first end  104  and the second end  106  of the second ramp  102 . The relative sliding of these oppositely facing helical surfaces (top surfaces  56  and  72  of the first body  12  and bottom surfaces  98  and  108  of the second body  18 ) cause the first body  12  and the second body  18  to move away from each other, specifically, causes the top  22  of the second body  12  to move away from the bottom  14  of the first body  12 . 
         [0029]    The foregoing description is of, essentially, ramps on the first body, formed by the tops  58 ,  72  of the first and second curved walls  50 ,  66  and ramps on the second body  18 , namely the first and second ramps  92 ,  102 . However, it is only necessary that a ramp be formed on one of the first and second bodies  12 ,  18 . The other body can be provided with a structure that may be described as a “ramp follower” or a structure that slides along the ramp of the other body as the first and second bodies rotate. This is because the surfaces of the ramps are only in substantially full contact in the non-use configuration. After relative rotation between the first body  12  and second body  18  begins, it is merely necessary to have a structure on the second body  18  slide along the ramp or ramps on the first body  12  or a structure on the first body  12  slide along the ramp or ramps on the second body  18 . However, for ease of assembly and manufacture, and to provide stability when assembled in the non-use configuration, ramps on both the first body  12  and the second body  18  are disclosed in this embodiment. In other words, in this embodiment, the ramp follower takes the form of a ramp. 
         [0030]    The first body  12  and the second body  18  are rotatable relative to one another from a first angular relationship, illustrated in  FIG. 4 , to a second angular relationship illustrated in  FIG. 5 , and this rotation causes the top  22  of the second body  18  to move away from the bottom  14  of the first body  12 . This movement, in turn, pulls the flange  140  at the second end  139  of the hollow shaft  30  toward the bottom  14  of the first body  12  and compresses the seal  24 . The compression of the seal  24  occurs in two stages, discussed below in connection with  FIGS. 7 and 8 . 
         [0031]    In the present embodiment, the first and second angular relationships are separated by about one full turn or by 360°. As used herein, 0° and 360° are two different angular relationships; that is, turning one of the first body  12  and the second body  18  relative to the other body by 360° constitutes moving the bodies from a first to a second angular relationship. This use of ramps allows the first body  12  to be axially separated from the second body  18  by a distance useful for forming a seal while undergoing only approximately a single turn (about a 360° relative change in angular position). This is not possible using a screwthread having a single turn because the maximum helix angle of screwthreads allows only a small separation to be obtained with a single rotation, and thus conventional devices that use screwthreads must be turned multiple times to achieve a useful separation between two bodies. 
         [0032]      FIG. 7  illustrates the seal second portion  28  inserted in a relatively narrow filler neck  146  of a radiator (not illustrated) with the spacer  124  resting on an end of the filler neck  146 . In  FIG. 7 , the first body  12  and second body  18  have been rotated away from the storage configuration of  FIG. 4  a sufficient angular distance to pull the flange  140  toward the spacer  124  and compress the second end  136  of the seal second portion  28  toward the first end  132  of the seal second portion  28  to deform the seal second portion  28 . This presses the outer wall of the seal second portion  28  tightly against the inside wall of the filler neck  146  and forms a seal with the filler neck  146 . The outer wall of the seal second portion  28  is pressed against the inside wall of the filler neck  146  with sufficient force that no fluid can pass between the seal second portion  28  and the inside of the filler neck  146 . The hollow shaft  30  can be selectively blocked, for example with a suitable cap (not illustrated). Thus, in this configuration, fluid cannot pass around the outside of the adapter  10  and can only pass through the hollow shaft  30  when the hollow shaft  30  is open. 
         [0033]    Friction between the ramp surfaces (the top surface  56  of the first curved wall  50  against the bottom surface  98  of the first ramp  92  and the top surface  72  of the second curved wall  66  and the bottom surface  108  of the second ramp  102 ) and the relative angles of these ramp surfaces causes the first body  12  and second body  18  to maintain a relative orientation after being rotated to this first sealing position without sliding back toward their starting relationship. 
         [0034]      FIG. 8  illustrates the adapter  10  inserted into a filler neck  148  that is larger than the diameter of the seal second portion  28 . In this case, the tapered or conical seal first portion  26  is inserted into the filler neck  148  until an outer wall of the seal first portion  26  comes into contact with the opening of the filler neck  148 . The first body  12  is held in place relative to the filler neck  148 , and the second body  18  is rotated relative to the first body  12  to draw the second end  139  of the shaft  30  toward the bottom  14  of the first body  12 . As mentioned above, the second end portion  139  of the hollow shaft  30  has a diameter larger than the width of the central opening  130  in the spacer  124 . The seal second portion  28  of the seal  24  is also more readily deformed than the first portion  26  of the seal. Therefore, when the first body  12  and the second body  18  are first rotated away from the storage configuration described above, substantially all deformation of the seal  24  occurs in the seal second portion  28 . This deformation continues until the second portion  139  of the hollow shaft  30  reaches the central opening  130  of the spacer  124 , after which further upward force is applied against the spacer  124  and the small end  122  of the seal first portion  26  to compresses the seal first portion  26 . The seal first portion  26  may be slightly deformed as the seal second portion  28  is compressed, but most of the deformation occurs in the seal second portion  28  until the second end portion  139  of the hollow shaft  30  reaches the central opening  130  in the spacer  124 . Continued rotation of the second body  18  relative to the first body  12  pulls the spacer  124  and the small end  122  of the seal first portion  26  toward the bottom  14  of the first body  12  and causes the seal first portion  26  to bulge outwardly and press the outer wall of the seal first portion  26  tightly against the interior wall of the filler neck  148  to form a seal therewith that substantially prevents the passage of fluid between the outer wall of the seal first portion  26  and the inside of the large filler neck  148 . Once sealed in the small filler neck  146  or the large filler neck  148 , air can be removed from a radiator connected to one of the filler necks  146 ,  148 , in a conventional manner with the seal formed between the seal  24  and the interior of the small filler neck  146  or the large filler neck  148  being sufficient to maintain a partial vacuum in the radiator. 
         [0035]    Upward movement of the hollow shaft  30  relative to the first body  12  is limited by the second disk  144  which cannot move past the top  48  of the central chamber  46  of the first body  12 . This prevents the second body  18  from being removed from the first body  12  and also limits the degree to which the seal first portion  26  can be compressed to reduce the likelihood of damaging the seal  24  by over compression. However, movement between the first body  12  and the second body  18  in a direction along the longitudinal axis of the hollow shaft  30  is not otherwise limited, and the first and second bodies  12 ,  18  are not interlocked as they would be if they were connected with screwthreads. In other words, the first body  12  and the second body  18  could be pulled away from one another without relative rotation if sufficient force were applied. 
         [0036]    The present invention has been described herein in terms of a presently preferred embodiment. Modifications and/or additions to this embodiment will become apparent to persons of ordinary skill in the art upon a reading of the foregoing description. It is intended that all such modifications and additions form a part of the present invention to the extent they fall within the scope of the several claims appended hereto.