Abstract:
A method of manufacturing a prosthetic socket having an access port that employs a housing with a cylindrical extension. The method includes the step of molding a shell over a socket model and a mold dummy to form an intermediate port. The method additionally includes the step of trimming the intermediate port along a trim line passing through a cavity defined by the mold dummy to create a circular opening in the shell. The mold dummy has a first diameter generally conforming to a diameter of the cylindrical extension of the housing. The method further includes the steps of passing the cylindrical extension through the opening and securing the access port to the shell.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application No. 60/589,226, filed on Jul. 19, 2004. The disclosure of the above application is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention generally relates to prosthetic suction socket suspension systems. More particularly, the present invention relates to a socket port for a prosthetic suction socket suspension system. The present invention also pertains to a related method of manufacture. 
   BACKGROUND OF THE INVENTION 
   Various prosthetic devices for limb replacement are known in the art. Many such prosthetic devices include a socket that serves as the connection between the user (amputee) and the prosthesis. For load bearing prostheses (e.g., lower limb prostheses, such as above knee prostheses), the weight of the amputee is transferred to the ground through the socket. 
   For most patients, a socket-type prosthesis can be held in place by a negative pressure or vacuum created between the close fit of a residual limb and the socket. The successful fitting of a prosthetic socket results in the effective transfer of forces from the socket to the residual limb such that the amputee can maintain daily activities without tissue damage or pain. 
   While significant advancements have been made in the field of prosthetic sockets in recent years, all known devices are associated with certain limitations. In this regard, prosthetic sockets are not designed to maintain suitable vacuum for high vacuum socket systems. In this regard, known high vacuum socket systems generally achieve a vacuum in the range of approximately 15-25 inches of mercury. Access plugs for such socket systems do not sufficiently seal with the shell to maintain this high level vacuum. Additionally, known prosthetic sockets cannot alternatively be used for high vacuum applications by incorporating a plug and standard vacuum applications by incorporating a valve. 
   A need remains in the art for a prosthetic socket which overcomes the limitations associated with the prior art, including but not limited to those limitations discussed above. 
   SUMMARY OF THE INVENTION 
   In one form, the present invention provides a method of manufacturing a prosthetic socket having an access port. The access port has a housing with a cylindrical extension. The method includes the step of molding a shell over a socket model and a mold dummy to form an intermediate port. The method additionally includes the step of trimming the intermediate port along a trim line passing through a cavity defined by the mold dummy to create a circular opening in the shell. The mold dummy has a first diameter generally conforming to a diameter of the cylindrical extension of the housing. The method further includes the steps of passing the cylindrical extension through the opening and securing the access port to the shell. 
   Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
       FIG. 1  is a cross-sectional view of a portion of a prosthetic socket taken through an access port of the prosthetic socket. 
       FIG. 2  is a cross-sectional view similar to  FIG. 1 , illustrating the shell of the prosthetic socket after molding and prior to trimming and introduction of the access port. 
       FIG. 3  is a cross-sectional view of a portion of a prosthetic socket of a second embodiment taken through an access port of the prosthetic socket. 
       FIG. 4  is a cross-sectional view similar to  FIG. 3 , illustrating the shell of the prosthetic socket after molding and prior to trimming and introduction of the access port for the second embodiment. 
   

   DETAILED DESCRIPTION OF THE EMBODIMENTS 
   The following description of the embodiments of the present invention is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
   With initial reference  FIG. 1 , a prosthetic socket constructed in accordance with the teachings of the present invention is illustrated and generally identified at reference character  10 . As described below, the prosthetic socket may be used for a high vacuum application. It will be noted, however, that the teachings of the present invention are not so limited. 
   The prosthetic socket  10  of the present invention may generally include a socket shell  12 . The socket shell  12  defines an interior  14  for receiving the residual limb (not shown) of the amputee. In one particular application, the socket shell  12  may be vacuum formed of a thermoplastic material. Those skilled in the art, however, will readily appreciate that other materials having suitable strength, flexibility, and durability characteristics may be alternatively used. 
   The prosthetic socket  10  may further generally include an access port  16 . The access port  16  facilitates pull-in access for donning the prosthesis. The access port  16  may be secured to the shell  12  at an opening  18  and may include a base or housing  20 . The housing  20  may include a lower flange portion  22  having a circular lip  24  that projects toward an inner surface  26  of the shell  12 . A gap may be defined by the lower flange portion  22  and the circular lip  24  which accommodates an O-ring seal  28 . The O-ring seal  28  can be compressed against the inner surface  26  of the shell  12 . 
   The housing  20  may further include a cylindrical extension  30  that extends through the opening  18  of the shell  12 . The cylindrical extension  30  may define a cylindrical opening  32  that receives an access plug  34 . The access plug  34  may be inserted into the cylindrical opening  32  along a centerline axis  36 . As shown, the access plug  34  seals the interior  14  of the shell  12 . The access plug  34  may be removed for donning or to allow air into the interior  14  of the shell  12  through the opening  18 . An O-ring seal  38  may be carried within a circumferentially defined groove  40  of the access plug  34 . 
   The housing  20  of the access port  16  may be secured to the shell  12  by a clamp nut  42 . In this regard, the clamp nut  42  may define an opening  18  that threadably engages the cylindrical extension  30  of the housing  20 . The clamp nut  42  may include an upper flange portion  46  having a circular lip  48  that projects toward an outer surface  50  of the shell  12 . A gap may be defined by the upper flange portion  46  and the circular lip  48  which accommodates an O-ring seal  52 . The O-ring seal  52  may be compressed against the outer surface  50  of the shell  12 . 
   Turning to the cross-sectional view of  FIG. 2 , a portion of the shell  12  of the prosthetic socket  10  is shown after vacuum molding but prior to trimming and installation of the access port  16 . The shell  12  may be vacuum formed about a socket model  60 . The socket model  60  may define a vacuum vent hole  62  and may be generally shaped to conform to the desired configuration of the interior  14  of the shell  12 . 
   The shell  12  may be specifically configured to accommodate the access port  16  through use of a mold dummy  64 . The mold dummy  64  may create the exact shape and hole diameter to match the housing  20  (with O-ring  28  fitted on the access port  16 ) of the access port  16 . In this manner, the housing  20  may facilitate optimum compression on the O-ring seal  28  and thereby provides reliable sealing of the access port  16  to a minimum of 27 inches of mercury. The outer O-ring seal  52  primarily provides sealing redundancy. 
   The mold dummy  64  may define a vent hole  65  and may include an upper diameter and a lower diameter. The upper diameter may generally conform in size to the cylindrical extension  30  of the housing  20 . The lower diameter may generally conform in size to the countersunk recess  67  defined on the inner surface  26  of the shell  12 . The mold dummy  64  may have a downwardly extending cylindrical lip  66  and an upwardly extending cylindrical lip  68 . The downwardly extending lip  66  may define the depth of the countersunk recess  67 . The upwardly extending cylindrical lip  68  may define a groove that receives the lip  24  of the housing  20  thus providing a radial lock between the housing  20  and the shell  12 . A foam cover disc  70  may be placed upon the mold dummy  64  during molding. The mold dummy  64  may be screwed, pinned or otherwise suitably attached to the socket model  60 . 
   After the shell  12  is vacuum molded to the shape shown in  FIG. 2  and allowed to suitably cool, the shell may be trimmed along a trim line  72 . The trim line  72  may pass through a cavity formed by the mold dummy  64 . Trimming along the trim line opens the opening  18  (see  FIG. 1 ) for introduction of the access port  16 . 
     FIG. 3  depicts a second embodiment of a prosthetic socket  100 . The prosthetic socket  100  of  FIG. 3  is similar to the prosthetic socket of  FIG. 1 ; however, distinct advantages of the prosthetic socket  100  of the present embodiment will be made evident. A description of the operative workings of the prosthetic socket according to the second embodiment will now be described. 
   The prosthetic socket  100  of  FIG. 3  may provide the same prosthetic socket access port as the socket of  FIG. 1 . The socket  100  can be used with valves as well as plugs. Additionally, the socket  100  installs reliably in super flexible socket materials and rigid socket port materials. This added functionality of accommodating either flexible or rigid materials means that the socket  100  can be reliably installed in materials such as polypropylene (PP), which is a very rigid plastic, low density polyethylene (PE), which is a soft and flexible thermoplastic, and silicon, which is soft and flexible and used as a padding material in sockets. While the socket  100  is primarily designed for conventional suction sockets, the system will work in high vacuum sockets, which increases its attractiveness with regard to multiple applications. 
   The prosthetic socket  100  of the teachings of the second embodiment may include a socket shell  102 . The socket shell  102  defines an interior  104  for receiving a residual limb (not shown) of the amputee. The socket shell  102  may be vacuum formed from a thermoplastic material, although those skilled in the art will appreciate that other suitable materials may be used. 
   The prosthetic socket  100  may include an access port  106 . The access port  106  may facilitate pull-in access for donning the prosthesis. The access port  106  may be secured to the shell  102  at an opening  108  and may include a base or housing  110 . The housing  110  may include a lower flange portion  112  that is responsible for locking and sealing with the shell  102 . More specifically, the lower flange portion  112  may contain, on its top side, an outer lip  114 , also known as a lock rib  114 , an intermediate lip  148 , a recession for an O-ring seal  118 , and a recession for a shell lip  134 , also known as a shell lock rib  134 . The shell  102  may contain a countersink recession  113  to better accommodate the fitting and assembly of the outer lip  114 , the tip of which protrudes toward the inner surface of the shell  102  to fit into a further recession of the shell  102 . 
   To facilitate sealing of the housing  110  with the shell  102 , the O-ring seal  118  may be interposed and compresses between the outer lip  114  and the intermediate lip  148 . The intermediate lip  148  may abut against the shell lip  134 , which abuts against the cylindrical extension of the housing  110 . In concert, the outer lip  114 , intermediate lip  148  and shell lip  134 , may all work together to prevent movement. 
   The housing  110  may further include a cylindrical extension  120  that extends through the opening  108  of the shell  102 . The cylindrical extension  120  may define a cylindrical opening  122  that receives a closure member  124 . The closure member may be in the form of an access plug  124 , as shown in the drawings. The closure member  124  may also be in the form of a valve. The closure member  124  may be inserted into the cylindrical opening  122  along its axis  126 . As depicted in  FIG. 3 , the closure member  124  may seal the interior  104  of the shell  102  in a variety of ways. The closure member  124  may be equipped with an O-ring seal  128  that is accommodated within a groove  130  of the O-ring. The O-ring seal  128  may be compressed within the groove  130  and abut against an end bore of the cylindrical extension  120  to create a seal when the closure member  124  is tightened. The access plug  124  may be removed for donning or to allow air into the interior  104  of the shell  102  through the opening  108 . 
   The housing  110  of the access port  106  may be secured to the shell  102  by a clamp nut  132 . In this regard, the clamp nut  132  may define an opening  108  that threadably engages the cylindrical extension  120  of the housing  110 . The clamp nut  132  may include an upper flange portion  136  having a clamping flange  138  that projects toward an outer surface  142  of the shell  102 . The clamping flange  138  may have a plurality of circular ridges  140  on its face that face a clamping land  143  of the outer surface  142  of the shell  102 . The circular ridges  140  may provide an even distribution of the clamping force of the clamp nut  132  against the clamping land  143 . The force of the clamping nut  132  may bear against the shell  102  and the lower flange portion  112  which ultimately causes the compression of the O-ring seal  118  between the shell  102 , the lower flange portion  112 , the intermediate lip  148 , and the outer lip  114 . Additionally, the shell lip  134  and the intermediate lip  148  may overlap and abut to provide radial locking of the device. Such is also the effect of the outer lip  114  within the shell  102 . In this manner, the housing  110  may be prevented from moving laterally within the socket  100 . 
   In addition to the forgoing advantages related to movement and sealing, parts may be also eliminated. More specifically, the O-ring seal  52  and the associated machining necessary to accommodate it within the clamp nut  42  are eliminated. This may provide a cost and part count reduction. 
   Turning to the cross-sectional view of  FIG. 4 , a portion of the shell  102  of the prosthetic socket  100  is shown after vacuum molding but prior to trimming and installation of the access port  106 . Similar to the first embodiment, the shell  102  may be vacuum formed about a socket model  150 . The socket model  150  may define a vacuum vent hole  152 , which vents the vent area  164 , the socket model being generally shaped to conform to the desired configuration of the interior  104  of the shell  102 . 
   The shell  102  may be specifically configured to accommodate the access port  106  through use of a mold dummy  154 . The mold dummy  154  may create the exact shape and hole diameter to match the housing  110  of the access port  106 . The mold dummy  154  may also account for space to fit the O-ring seal  118  of the housing  110 . In this manner, the housing  110  may facilitate optimum compression on the O-ring seal  118  and thereby provides reliable sealing of the access port  106  to a minimum of 27 inches of mercury. The prosthetic socket  100  of the second embodiment as depicted in  FIG. 3 , departs from the prosthetic socket  10  of the first embodiment depicted in  FIG. 1 , wherein the outer O-ring seal  52  of the first embodiment, which primarily provides sealing redundancy, is not necessary on the second embodiment. 
   Furthermore, the mold dummy  154  may define a vent hole  162  and may have an upper diameter and a lower diameter. The upper diameter may generally conform in size to the cylindrical extension  120  of the housing  110 . The lower diameter may generally conform in size to the countersunk recess  113  defined on the inner surface  116  of the shell  102 . The mold dummy  154  may have a downwardly extending cylindrical lip  158  and an upwardly extending cylindrical lip  160 . The downwardly extending lip  158  may define the depth of the countersunk recess  113 . The upwardly extending cylindrical lip  160  may define a groove that receives the outer lip or lock rib  114  of the housing  110  thus providing a radial lock between the housing  110  and the shell  102 . A foam cover disc  156  may be placed upon the mold dummy  154  during molding. The mold dummy  154  may be screwed, pinned or otherwise suitably attached to the socket model  150 . 
   After the shell  102  is vacuum molded to the shape shown in  FIG. 4  and allowed to suitably cool, the shell  102  may be trimmed along a trim line  166 . The trim line  166  passes through a cavity formed by the mold dummy  154 . Trimming along the trim line  166  opens the opening  108  (see  FIG. 3 ) for introduction of the access port  106 . 
   In one particular application, the prosthetic sockets  10 ,  100  described above are for a high vacuum, lower limb, above knee prosthesis. It will be understood, however, that the teachings of the present invention are also applicable for other applications. For example, in one alternative application, the sockets  10 ,  100  may be used for conventional suction socket applications by replacing the plug  34 ,  124  with a valve (not particularly shown). Other applications will be apparent to those of ordinary skill in the art. 
   While the component parts of a prosthetic socket  10 , 100  according to the teachings of the present invention are described above, a method of manufacturing the prosthetic socket is also known. According to the teachings of the present invention, manufacturing a prosthetic socket  10 ,  100  having an access port  16 , 106  entails determining a valve location on a socket model  60 ,  150  and flattening or leveling an area to ensure that the mold dummy  64 ,  154  sits flush or flat. A pilot hole may be drilled into the socket model for mounting the mold dummy  64 ,  154  to the socket model  60 ,  150  with a screw (not shown). Additionally, a vacuum hole  62 ,  152  may be drilled adjacent to the pilot hole and extends to the bottom of the cast model. Next, the mold dummy may be mounted with small air holes in a position over the pilot and vacuum holes. The self-adhesive foam disk  70 ,  156  may be placed over the screw head. 
   After mounting the self-adhesive foam disk, the heated thermoplastic material  12 ,  102  may be guided around the mold dummy in a fashion to blister or drape mold the thermoplastic socket  12 , 102 . The heated plastic may be permitted to cool and a disc sander or equivalent material removing device may be used to remove enough plastic to permit removal of the self-adhesive disc  70 ,  156  and screw. Sanding or an equivalent material removing method may be continued until the face of the mold dummy  64 ,  154  is slightly scuffed and the cast plastic is flush with the dummy face, as noted by the trim line  72 ,  166 . This method results in a smooth and flush interface surface of the mold dummy  64 ,  154  and its corresponding socket shell  12 , 102 , that is, the cast plastic. 
   The socket model  60 ,  150  and the mold dummy  64 ,  154  may be removed from the cast model  12 ,  102  upon cooling of the cast, and the housing  20 ,  110  may be inserted through the socket shell  12 ,  102  from the mold dummy side, the housing having an O-ring seal  28 ,  118  installed in it before its insertion to ensure proper sealing. The clamp nut  42 ,  132  may be screwed onto the cylindrical extension  30 ,  120  of the housing  20 ,  110  and the nut is tightened. To complete the installation, the access plug  34 ,  124  or valve may be inserted and turned to tighten it within the cylindrical opening  32 ,  122  of the cylindrical extension  30 ,  120 . 
   Advantages of the D-Loc System are its suitability for super flexible and rigid socket materials, its broad clamping flange  138 , its second locking groove adjacent the cylindrical extension  120 , and an aggressive outer locking rib  114  on the housing  110 . The broad, ribbed face on the clamp nut  132  provides a broader clamping surface area than other socket access ports. Finally, the outer O-ring seal  52  of the socket of  FIG. 1 , which primarily provides redundant sealing, is not necessary with the second embodiment of  FIG. 3 . 
   The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.