Abstract:
Systems and methods according to the present invention provide casting molds having improved separability from cured molding material. A first system and method employ an extraction rim which provides a clamping surface to be used in conjunction with an extraction bridge which straddles a mold. A second system and method employ a reusable, expandable molding mandrel that may be used to form voids in a casting. A third system and method employ both the extraction rim and the reusable, expandable molding mandrel.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Embodiments of the present invention relate generally to casting or molding, and more particularly to molds and related systems having improved separability from cured castings. 
         [0002]    In the art of product casting, especially when using a material such as concrete, the removal or separation of a mold from a cured casting can be a difficult task when care is taken to avoid damage to the casting or mold. While various prior attempts have been made at improving mold-casting separability, there remains significant room for improvement, especially related to void-forming molds. 
         [0003]    For instance, some prior devices provide handles to improve the manual separation process. Generally, the handles are provided at discrete locations, usually two locations, on the inside of the mold. Two types of handles have been employed on prior molds in an attempt to ease extraction. First, individual metal grip or pull handles have been either adhered or otherwise fastened to the mold wall. While the metal handles are substantially rigid, they are generally shaped so as to hamper any sort of use in conjunction with a mechanical separation aid, such as a clamping member. Further, due to the limited area of force application by the handle to the mold, a stress riser is created where the handles are joined to the mold, thereby risking damage to the mold, such as cracking, or at least decreased mold life due to sometimes severe flexing of the mold housing. Second, individual wood handles have been either adhered or otherwise fastened to the mold wall. The discrete wood handles, not being as rigid as the metal handles, tend to flex when the required extraction force is applied thereto. Thus, the force application to the handle can be unpredictable. Further, as with the metal handles, due to the limited area of force application by the handle, a stress riser is created where the handles are joined to the mold, thereby risking damage to the mold, such as cracking, or at least decreased mold life due to sometimes flexing of the mold housing. Even where handles have been generally effective for removing molds, the molds, especially fiberglass molds, may be prone to chipping at the perimeter edge thereof. 
         [0004]    Accordingly, the art of molding would benefit from void-forming molds or components thereof that have improved extraction or separation and reinforcement characteristics. 
       SUMMARY OF THE INVENTION 
       [0005]    Embodiments of the present invention provide void-forming molds or components thereof that have improved extraction or separation characteristics. 
         [0006]    An embodiment of a mold according to the present invention includes a housing formed partially around a cavity. The housing has at least one working surface adapted to receive a molding material. The working surface defines a mold perimeter. Extending radially inward from the mold perimeter is an extraction rim. 
         [0007]    According to an aspect of an embodiment of a mold according to the present invention, the extraction rim comprises a substantially planar plate. The plate may completely surround at least one aperture formed therethrough. 
         [0008]    According to another aspect of an embodiment of a mold according to the present invention, a mold may further include a void-forming mandrel coupled to the housing adjacent to and extending away from one of the at least one working surface. The void-forming mandrel, which may include a radially expansible member, may be detachably coupled to the housing. The radially expansible member may include an elastomeric bushing having a predetermined hardness, such as about 30 Shore. 
         [0009]    An embodiment of a mold kit according to the present invention includes an embodiment of a mold according to the present invention and a first extraction bridge adapted to span a first portion of the mold perimeter. The mold kit may further include at least one clamping member, which may comprise a support beam, a first jaw member fixed to one end of the support beam, a second jaw member slidably disposed on the support beam, and a clamping force applicator disposed at least partially between the first and second jaw members. The clamping force applicator may include a threaded rod extending through one of the jaw members, such as the second jaw member. 
         [0010]    According to an aspect of an embodiment of a mold kit according to the present invention, the kit may further include a first clamp contact pad disposed on the first jaw member, wherein all points of the first clamp contact pad are located at a jaw depth that is less than or equal to the maximum width of the extraction rim. 
         [0011]    According to an aspect of another embodiment of a mold kit according to the present invention, two extraction bridges may be provided, which may be adapted to span the same or different portions, such as the diameter, of the mold perimeter. The multiple bridges may be adapted to function in an overlapping relationship to each other. 
         [0012]    An embodiment of a method of molding according to the present invention includes the steps of providing an embodiment of a mold according to the present invention and providing a mold extraction bridge. Casting material, such as concrete, is disposed on a working surface of the mold. The casting material is allowed to cure, and the mold is removed from the cured casting material using the mold extraction rim and the mold extraction bridge. 
         [0013]    According to an aspect of an embodiment of a method of molding according to the present invention, the step of removing the mold from the cured casting material may include the step of spanning a portion of the mold perimeter with the mold extraction bridge. A clamping member may be interfaced to the extraction bridge and the extraction rim, and the extraction rim may be drawn towards the extraction bridge using the clamping member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view of a first embodiment of a mold according to the present invention. 
           [0015]      FIG. 2  is a cross-section view taken along line  2 - 2  of  FIG. 1 . 
           [0016]      FIG. 3  is a cross-section view taken along line  3 - 3  of  FIG. 1 . 
           [0017]      FIG. 4  is a perspective view of a second embodiment of a mold according to the present invention. 
           [0018]      FIG. 5  is a cross section view taken along line  5 - 5  of  FIG. 4 . 
           [0019]      FIG. 6A  is a first perspective view of a third embodiment of a mold according to the present invention. 
           [0020]      FIG. 6B  is a second perspective view of the embodiment of  FIG. 6A . 
           [0021]      FIG. 6C  is a cross-section view taken along line  6 C- 6 C of  FIG. 6A . 
           [0022]      FIG. 7  is a perspective view of the mold of  FIG. 1  being placed into a casting tray. 
           [0023]      FIG. 8  is a perspective view of the mold of  FIG. 1  placed at least partially within the casting tray. 
           [0024]      FIG. 9  is a perspective view of the arrangement of  FIG. 8 , further including casting material being poured into the casting tray and at least partially over the mold. 
           [0025]      FIG. 10  is a cross-section view taken along line  10 - 10  of  FIG. 9  once the casting tray has been filled to a desired capacity with the casting material. 
           [0026]      FIG. 11  is a perspective view of an assembly combination including the mold and cured casting, the assembly combination having been removed from the casting tray. 
           [0027]      FIG. 12A  is a perspective view of an extraction bridge and clamps being used with the assembly combination of  FIG. 11 . 
           [0028]      FIG. 12B  is an elevation view of a preferred embodiment of a clamp as used in  FIG. 12A . 
           [0029]      FIG. 13  is a first cross-section view taken along line  13 - 13  of  FIG. 12A . 
           [0030]      FIG. 14  is a second cross-section view taken along line  13 - 13  of  FIG. 12A . 
           [0031]      FIG. 15  is a third cross-section view taken along line  13 - 13  of  FIG. 12A , after removal of the mold, the bridge and the clamps. 
           [0032]      FIG. 16  is a perspective view of the mold of  FIG. 4  being placed into a casting tray. 
           [0033]      FIG. 17  is a perspective view of the mold of  FIG. 4  placed at least partially within the casting tray. 
           [0034]      FIG. 18A  is a first cross-section view taken along line  18 - 18  of  FIG. 17 . 
           [0035]      FIG. 18B  is a second cross-section view taken along line  18 - 18 . 
           [0036]      FIG. 19  is a perspective view of the arrangement of  FIG. 8 , further including casting material being poured into the tray and at least partially over the mold. 
           [0037]      FIG. 20  is a first cross-section view taken along line  20 - 20  of  FIG. 19 . 
           [0038]      FIG. 21  is a second partial cross-section view taken along line  20 - 20  of  FIG. 19 . 
           [0039]      FIG. 22  is a third cross-section view taken along line  20 - 20  of  FIG. 19  showing the plug being removed. 
           [0040]      FIG. 23  is a cross-section view similar to  FIG. 14 , including a substitution of the mold of  FIGS. 6A-6C  for the mold of  FIG. 1 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0041]    Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. 
         [0042]    Turning now to the figures,  FIGS. 1-3  provide a first embodiment  100  of a mold according to the present invention. The mold  100 , in this case a void-forming sink mold, generally comprises a housing  110  which provides at least one working surface  112  adapted to receive a molding material, such as concrete. The embodiment  100  shown provides three working surfaces  112   a , 112   b , 112   c  which define a perimeter edge  114 . The housing  110  further includes an extraction rim  116  extending radially inwardly from the perimeter edge  114 . 
         [0043]    While gaps may be created and reinforced, the extraction rim  116  is preferably disposed adjacent the entire perimeter edge  114 . The at least one working surface  112  is preferably provided by a shell  120 , which at least partially defines a mold cavity  122 . The shell  120  preferably includes at least one wall  121  of a desired thickness  123 , such as about 3/16 of an inch, the at least one wall  121  preferably extending to and forming the outer perimeter  114  of the mold  100 . While it may be desirable to provide a wall  121  of substantially consistent thickness  123  to aid in predictability of manufacture and performance, such consistency is not required. The wall  121  may extend to a terminal edge  121   a . Although shown as rectangular, it is to be understood that the shape of the outer perimeter  114  is not limiting. Further, although shown in a partial “drum” shape, it is to be understood that the shape of the shell  120  is not limiting. 
         [0044]    The extraction rim  116  is preferably provided as a plate  118  which is secured to or formed integrally with the shell  120 . The plate  118  is preferably provided as a substantially planar plate having an outer perimeter  124 , at least one aperture  126 , a thickness  128  between an inner surface  125  and an outer surface  127 , and a maximum width  129 . The plate  118  includes an inner edge  130  provided along each aperture  126 . The plate  118 , around at least part of one of the at least one aperture  126  is preferably rounded so as to provide comfort and to help prevent injury during handling of the mold  100 . For instance, the bottom inside edge  130   a  or the top inside edge  130   b  or both, could be rounded. The outer edge  124  is preferably shaped to form a mating relationship with an inner surface  131  of the shell  120 . The plate  118  may be formed to be coupled to the shell  120  immediately adjacent to the perimeter  114 , thus creating a generally smooth transition from plate  118  to the terminal edge  121   a  of the shell  120 , as shown. This arrangement provides the added benefit of further reinforcement of the shell  120  to help prevent damage to the perimeter  114 . The plate inner surface  125  provides a clamping contact surface  133 , which is preferably generally a planar surface disposed at a desirable angle  135  with respect to the inner surface  131  and/or working surface  112  of the mold  100 , or a tangent thereof. The desirable angle  135  is preferably less than or equal to ninety degrees. At least the outer surface  127  of the plate  118  is preferably coated with a protective coating such as a chemical resistant lacquer primer. Such protective coating helps to prevent absorption of release agents that may be applied to the mold  100  and further has been discovered to aid in the mold/casting separability. 
         [0045]    While other materials could be used, the shell  120  is preferably formed from an industrial fiberglass resin material having the working surfaces  112  covered with a gel coat, and the plate  118  is preferably a laminate plywood material of a desired thickness, such as ⅝ of an inch. The shell  120  may also be formed from other materials such as thermoform acrylic or ABS plastic. If formed from these other materials, it may still be desirable to coat the working surfaces  112  with a gel coat. 
         [0046]      FIGS. 4-5  depict a second embodiment  200  of a mold according to the present invention, wherein like reference numerals refer to similar or identical structure to that of the first embodiment  100 . The second embodiment  200  includes a void-forming mandrel  260  which extends outward from a working surface  212   c  of the mold  200 . The mandrel  260  is preferably a longitudinal body that is expandable in one or more radial directions. 
         [0047]    For instance, the mandrel  260  may include an elastomeric bushing  262  that is removably coupled to the mold shell  220 . The elastomeric bushing  262  has a desired hardness, such as less than 75 Shore and more preferably less than 50 Shore. The elastomeric bushing  262  is preferably formed from molded polyurethane rubber having a desired hardness, such as about 30 Shore. A threaded receiver nut  264  may cooperate with a threaded bolt  266  inserted through the bushing  262  to retain the mandrel  260  in an abutting relationship to the working surface  212   c.  The receiver nut  264  may be adhered to or formed integrally with the mold shell  220 , or it may be provided as a separate component to rest against the inner surface  231  of the shell  220 . It is to be understood that the bolt  266  and nut  264  may be transposed, such that head  268  of the bolt  266  is disposed against the inner surface  231  of the shell  220  and the nut  264  rests against a force distributing mechanism, such as a flat washer  269  or other rigid plate member. The operation of the mandrel  260  will be explained in further detail with reference to the second method embodiment below. 
         [0048]      FIGS. 6A-6C  depict a third embodiment  300  of a mold according to the present invention, wherein like reference numerals refer to similar or identical structure to that of the first two embodiments  100 , 200 . The third preferred mold embodiment  300  generally includes a combination of the first embodiment  100  with the expandable mandrel  260  of the second embodiment  200 . Thus, the exemplary embodiment  300  demonstrates that the extraction rim  116  may be used in a mold embodiment in combination with or without one or more expandable mandrels  260 , and vice versa. 
         [0049]      FIGS. 7-15  depict steps in a first method according to the present invention. In a first step  601 , a mold  100  and a casting form  400  of a desired size and shape are provided. The casting form  400  may be a closed form type, such as that shown, having a bottom  402  including a molding surface  404 , and side walls  406  having molding surfaces  408  that define a casting perimeter  410 . Alternatively, the casting form  400  may include only the walls  406 , without a bottom  402 , which may be elevated above a second form (not shown) so as to allow the molding material, such as concrete, to flow through the casting form  400  and into the second form (not shown). The casting perimeter  410  is preferably larger than the outer perimeter  114  of the mold  100 . As shown in  FIG. 7 , the mold  100  is placed in the casting form  400  on the molding surface  404 , wherein the outer perimeter  114  of the mold  100  and/or the extraction rim  116  lie adjacent the molding surface  404 . In a second step  602 , as shown in  FIG. 8 , a bead  412  of caulk or sealant  414 , preferably silicone caulk or sealant, may be applied at the junction of the outer perimeter  114  of the mold  100  and the molding surface  404  so as to prevent the seepage of the molding material under the mold  100 . Additionally, void-forming mandrels  160  may be placed in desirable locations. Such mandrels  160  may include drain hole forming plugs or mandrels used to create plumbing or other passageways, for example. 
         [0050]    Once the silicone caulk bead  412  is sufficiently cured, molding material  500 , such as concrete  502 , is added to the casting form  400  at least partially over the mold  100 , to a desired depth  501 , as shown in  FIGS. 9 and 10  in a third step  603 . Preferably, prior to adding the molding material  500 , a release agent is applied to the working surface(s)  112  of the mold  100  to assist in separating the mold  100  from a cured casting. The release agent may also be applied to the silicone caulk bead  412 , as well as the bottom molding surface  404  of the casting form  400 . Such release agents include barrier release agents, such as petroleum oils, water emulsions, waxes, or even soaps, as are known in the art. During or after the addition of molding material  500 , the casting form  400  may be vibrated so as to cause the molding material  500  to settle, thereby attempting to rupture most if not all of any air pockets that may have been formed in the uncured molding material  500 . In a fourth step  604 , the molding material  500  is allowed to cure for a desired, perhaps predetermined amount of time, such as overnight. 
         [0051]    In a fifth step  605 , after the molding material  500  has cured for a desired or specified amount of time, an assembly combination  420  including the mold  100  and the cured molding material  500  in the form of a casting  504  may be removed from the casting form  400 , or the casting form  400  may be removed from the assembly combination  420 . If the casting form bottom  402  is removable from the casting form  400 , the form  400  may be inverted and the bottom  402  removed, thereby exposing the at least one aperture  126  formed in the extraction plate  118 . An example of a resulting assembly combination  420  may be seen in  FIG. 11 . At this point, it is desirable to separate the casting  504  from the mold  100  working surface(s)  112  to reveal a void ( 506  in  FIG. 15 ) formed in the casting  504  thereby. 
         [0052]    Turning now to  FIGS. 12A-15 , to remove the mold  100  from the assembly combination  420 , an extraction bridge  450  is provided. The extraction bridge  450  preferably includes a span member  452  extending along a bridge gap length  454 , and abutment portions  456  coupled to or formed integrally with the span member  452 . The span member  452  has a top surface  458  and a bottom surface  460  which is oppositely disposed from the top surface  458 . The abutment portions  456  extend away from the bottom surface  460  of the span member  452  along an abutment length  462 . To extract the mold  100 , the bridge  450  is placed so as to straddle the mold  100 , the gap length  454  being preferably larger than the width  154  of the mold perimeter  114  at the location which the bridge  450  is situated. The bottom surface  460  of the span member  452  is spaced from the top surface  127  of the plate  118 . At least one clamping member  470  is provided. A preferred clamping member  470  is depicted in  FIG. 12B . The clamping member  470  includes a firs jaw member  472  and a second jaw member  474  disposed on a support beam  476 . The first jaw member  472  is preferably stationarily fixed to the support beam  476 , while the second jaw member  474  is preferably slidably disposed on the support beam  476 . A first clamp contact pad  478  is provided by or coupled to the first jaw member  472 . A clamping force applicator including a second clamp contact pad  480  is preferably coupled to the second jaw member  424 . The force applicator further includes a threaded rod  482 , which may threadably extend through the second jaw member  474 , and may be swivelly coupled to the second clamp contact pad  480  at one end and fixedly coupled to a handle  484  at the other end. The first jaw member  472  includes a jaw depth  473  which is measured from the beam  476  to the tip of the first clamp contact pad  478 . 
         [0053]    Returning now to  FIG. 12A , in a sixth step in the method, the provided clamping members  470  may be arranged so that the first clamp contact pad  478  is in direct or indirect contact with the inner surface  125  of the plate  118  and the second clamp contact pad  480  is in direct or indirect contact with the upper surface  458  of the bridge span member  452 . It is preferred to use at least one clamping member  470  on each side of the plate aperture  126  so that force can be applied to multiple points of the mold  100  simultaneously. Turning now to a seventh step  607  in the method, as shown in  FIG. 14 , the handles  484  of the clamping members  470  may be twisted so as to reduce the distance between the first clamp contact pad  478  and the second clamp contact pad  480 . This, in turn, draws the plate  118  towards the bridge  450 , eventually releasing the mold  100  from the casting  504 . While the same amount of force may be applied by each clamping member  470 , it is advantageous to allow the application of differing amounts of force. The mold/casting separation force is thought to be a function of the amount of surface area of the working surface  112  of the mold  100  which is exposed to the casting  504 . If the asthetic design of the mold  100  provides for greater contact surface area between the mold  100  and the casting  504  at one location and less at another, the ability to provide differing amounts of force is advantageous to effect a relatively simultaneous, complete mold/casting separation. Where an annular extraction rim  116  is provided, one or more bridges  450  may straddle the mold  100  at various positions to allow 360 degree clamping capability. Furthermore, it may be advantageous to provide a maximum extraction rim width  129  which is less than or equal to the associated clamp jaw depth  473 . This allows the first clamp contact pad  478  to be placed substantially anywhere on the inner surface  125  of the plate  118 . 
         [0054]      FIG. 15  depicts a casting  504  from which the mold  100  has been removed. The casting  504  may further include a drain indentation  508  formed by a protrusion  150  on the mold working surface  112   c  and may further include a drain aperture  510  formed by a mandrel  160 . 
         [0055]    In addition to the first extraction bridge  450 , a second extraction bridge  490  may be provided. The second extraction bridge  490  may be used in conjunction with the first extraction bridge  450 . The second extraction bridge  490 , like the first  450 , preferably includes a span member  492  extending along a bridge gap length  494 , and abutment portions  496  coupled to or formed integrally with the span member  492 . However, the abutment portions  496  may have a different abutment length  497  than the abutment length  457  of the first bridge  450 , which may allow for overlapping of the bridges  450 , 490  in the event that simultaneous use of the multiple bridges is desired. The overlapping bridges may be arranged at any desirable angle with respect to each other. Alternatively, the bridges  450 , 490  may be used in a parallel arrangement. 
         [0056]      FIGS. 16-22  depict steps in a second method according to the present invention. In a first step  701 , a mold  200  and a casting form  400  of a desired size and shape are provided. The casting form  400  may be a closed form type, such as that shown, having a bottom  402  including a molding surface  404 , and side walls  406  having molding surfaces  408  that define a casting perimeter  410 . Alternatively, the casting form  400  may include only the walls  406 , without a bottom  402 , which may be elevated above a second form (not shown) so as to allow the molding material, such as concrete, to flow through the casting form  400  and into the second form (not shown). The casting perimeter  410  is preferably larger than the outer perimeter  114  of the mold  200 . As shown in  FIG. 17 , the mold  200  has been placed in the casting form  400  on the molding surface  404 , wherein the outer perimeter  214  of the mold  200  and/or the extraction rim  216  lie adjacent the molding surface  404 . In a second step  702 , as shown in  FIG. 17 , a bead  412  of silicone caulk or sealant  414  may be applied at the junction of the outer perimeter  214  of the mold  200  and the molding surface  404  so as to prevent the seepage of the molding material under the mold  200 . In a third step  703 , a void-forming mandrel  260  is coupled, preferably removably coupled, to the mold housing  210 , extending away from a working surface  212 . Such mandrel  260  may include a drain-hole-forming plug, as shown, or mandrels used to create plumbing passageways, for example. The mandrel  260  is preferably a radially expandable mandrel which, in a fourth step  704 , is expanded to an expanded state. The preferred embodiment, as described above in connection with  FIGS. 4 and 5 , includes a void-forming mandrel  260  which extends outward from a working surface  212   c  of the mold  200 . The mandrel  260  is preferably a longitudinal body that is expandable in one or more radial directions  265 . The mandrel  260  preferably includes an elastomeric bushing  262  that is removably coupled to the mold shell  220 . In its free state, the bushing  262  has a first diameter or width  251 . A threaded receiver nut  264  may cooperate with a threaded bolt  266  inserted through the bushing  262  to retain the mandrel  260  in an abutting relationship to the working surface  212   c . The receiver nut  264  may be adhered to or formed integrally with the mold shell  220 , or it may be provided as a separate component to rest against the inner surface  231  of the shell  220 . The mandrel  260  further preferably includes a force distribution mechanism, such as a flat washer  269 . Thus, to expand radially the mandrel  260 , the threaded bolt  266  and nut  264  engagement is tightened. The tightening forces the washer  269  in a compression direction  263 , thus expanding the bushing  262  radially outwardly  265  to a second diameter or width  253 , which may be mated to other structure on the mold  200 , such as a mating protrusion  250 . The second diameter  253  is larger than the first diameter  251 . This expansion step  704  is preferably performed prior to the fifth step  705 , but it could be performed for some limited time thereafter, presuming the molding material  500  has not yet set. 
         [0057]    Once the silicone caulk bead  412  is sufficiently cured, molding material  500 , such as concrete  502 , is added to the casting form  400  over the mold  200 , to a desired depth  501 , as shown in  FIGS. 19 and 20  in a fifth step  705 . Preferably, prior to adding the molding material  500 , a release agent is applied to the working surface(s)  212  of the mold  200  to assist in separating the mold  200  from a cured casting. The release agent may also be applied to the silicone caulk bead  412 , as well as the bottom molding surface  404  of the casting form  400 . Such release agents include barrier release agents, such as petroleum oils, water emulsions, waxes, or even soaps, as are known in the art. During or after the addition of molding material  500 , the casting form  400  may be vibrated so as to cause the molding material  500  to settle, thereby attempting to rupture most if not all of any air pockets that may have been formed in the uncured molding material  500 . In a sixth step  706 , the molding material  500  is allowed to cure for a desired, perhaps predetermined amount of time, such as overnight. 
         [0058]    After a predetermined or desired amount of time, a sixth step in the second method involves the decompression of the mandrel bushing  262 . By loosening the threaded nut  264  and bolt  266  combination, the elastomeric bushing  262  is drawn in a radially inward direction  267 , which is preferably at least substantially, if not completely, directly opposite to the expansion direction  265 , due to its elastic properties. In this manner, a mandrel gap  280  is created between the mandrel bushing  262  and the cured casting  504 . This gap  280  facilitates removal of the mandrel  260  prior to or contemporaneously with the removal of the mold housing  210 . 
         [0059]      FIG. 23  depicts a third mold extraction method according to the present invention. The extraction method of  FIG. 23  is a combination of the first and second extraction methods, where the decompression or removal of the mandrel  360  is performed prior to the clamping extraction. 
         [0060]    It may be desirable to provide a mold according to the present invention in a kit form, i.e., all components in the same package or container, with one or more associated bridges  450 , one or more associated mandrels  160 , 260 , 360 , and/or at least one but preferably a plurality of clamping members  470 . In this way, the user of such kit could be provided with various size mandrels and/or clamping members, and specific feature pairings or correlations could be made. As was described earlier, it may be desirable to correlate a maximum extraction rim width  129  to the jaw depth  473  of a clamping member to be used with such rim  116 . 
         [0061]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.