Abstract:
An internal adapter for use in handles for interchangeable orthopedic tools contains a collar assembly, house assembly, retaining ring, spring and driver assembly. A plurality of securing ball mechanisms releasably secure an orthopedic tool in the adapter, while a configuration of chamfered surfaces centrally stabilize the tool. A plurality of guiding chamfers located in a shaft driver assembly rotationally secures the orthopedic tool.

Description:
FIELD OF INVENTION 
     The present invention relates to the field of medical devices, and more specifically to a self-locking internal adapter for securing medical tools. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of an exemplary embodiment of an internal adapter. 
         FIGS. 2   a  and  2   b  illustrate an exemplary embodiment of a collar assembly. 
         FIG. 3  is an exemplary embodiment of a house assembly. 
         FIGS. 4   a ,  4   b  and  4   c  illustrate an exemplary embodiment of a shaft driver assembly. 
         FIG. 5  is a cross-sectional view of an exemplary self-locking internal adapter with free guide mechanism. 
         FIG. 6  is an exemplary embodiment of the locking and securing mechanisms of a self-locking internal adapter. 
         FIG. 7  is an exemplary embodiment of a tool shaft for use with a self-locking internal adapter. 
         FIGS. 8   a ,  8   b  and  8   c  illustrate an exemplary embodiment of a self-locking internal adapter engaging an orthopedic tool. 
     
    
    
     TERMS OF ART 
     As used herein, the term “adapter” refers to a component of an orthopedic tool handle which engages a tool. 
     As used herein, the term “chamfer” refers to a beveled, angled or tapered edge which engages the edge of a second component to create a secured junction. 
     As used herein, the terms “flattened portion” or “partially flattened portion” refer to a cylindrical surface having an area with a curvature less than that of the cylindrical curvature. A flattened or partially flattened portion may contain a single area or multiple areas of lesser curvature. 
     BACKGROUND 
     Adjustment tools are used in orthopedic surgery to tighten and adjust mechanical components within orthopedic devices. For example, screwdrivers, spreaders, pliers, hammers, cutters and other tools may be used to adjust screws, pins, rods and other orthopedic devices. The adjustment tools for adjusting these orthopedic devices must be highly stable to allow for precise adjustments, and many types of adjustments may be needed. 
     In order to save space on an operating room instrument table or in a sterilization kit, different orthopedic tools may be designed to be interchangeable with a single handle. For example, it is known in the art to fashion tools of varying lengths with shafts that may be inserted into a single tool handle. 
     As a result, a typical orthopedic tool may actually be a system of three components: a handle, an adapter and a tool. Generally, the handle and the adapter are structurally integrated and permanently attached to other other. Tools are adapted for insertion into the adapter. 
     Adapters for securing medical tools, specifically medical tools with a square or hexagonal shaft, to handles are known in the art. Every adapter has some sort of channel or orifice to receive the tool, and a locking mechanism to secure the tool in place. The function and simplicity of operating the locking mechanism are critical. Even incremental improvements in a locking mechanism can be critical to the outcome of a surgery. 
     Tools must be compact to allow an orthopedic surgeon to perform adjustments to orthopedic devices and other tasks within the confined space of various body regions. 
     Tools must also be versatile, and it is desirable to have as many tools as possible adapted for use with a single adapter and handle. 
     Adapter components are likely to come in contact with bodily fluids and other contaminants during medical procedures. Any contours, grooves and other hard-to-reach surfaces need to be carefully cleaned and sterilized. Exposed attachment components are also more likely to be bumped or inappropriately forced in an attempt to attach a medical tool. As a result, exposed attachment components are frequently damaged. 
     It is desirable to have an adapter for securing medical tools to handles which reduce the number of exposed components and surfaces. 
     It is desirable to have an apparatus for securing and grasping tools which is as compact as possible so that surgeons can operate within the limited spaces and contours of various regions of the body. 
     It is critical to have an adapter for securing medical tools in place as effectively and simply as possible. 
     SUMMARY OF THE INVENTION 
     The present invention is an internal adapter for use in handles for interchangeable orthopedic tools. A plurality of securing ball mechanisms releasably secure an orthopedic tool in the adapter, while a configuration of chamfered surfaces centrally stabilize the tool. A plurality of guiding chamfers located in a shaft driver assembly rotationally secures the orthopedic tool. 
     DETAILED DESCRIPTION OF INVENTION 
     For the purpose of promoting an understanding of the present invention, references are made in the text to exemplary embodiments of an internal adapter for orthopedic tools, only some of which are described herein. It should be understood that no limitations on the scope of the invention are intended by describing these exemplary embodiments. One of ordinary skill in the art will readily appreciate that alternate but functionally equivalent structures and materials may be used. The inclusion of additional elements may be deemed readily apparent and obvious to one of ordinary skill in the art. Specific elements disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to employ the present invention. 
     It should be understood that the drawings are not necessarily to scale; instead, emphasis has been placed upon illustrating the principles of the invention. In addition, in the embodiments depicted herein, like reference numerals in the various drawings refer to identical or near identical structural elements. 
       FIG. 1  is an exploded view of an exemplary embodiment of self-locking internal adapter  100 . Internal adapter has collar assembly  10 , house  20 , retaining ring  30 , spring  40 , shaft driver assembly  50 , and securing balls  60   a ,  60   b ,  60   c ,  60   d . When assembled, internal adapter  100  is configured to be secured in handle  70 . 
     As illustrated in  FIG. 1 , collar assembly  10 , house  20 , retaining ring  30 , spring  40  and shaft driver assembly  50  are shown as separately manufactured components. In further exemplary embodiments, two or more of collar assembly  10 , house  20 , retaining ring  30 , spring  40  and shaft driver assembly  50  integrally manufactured or machined. In still further exemplary embodiments, one or more of collar assembly  10 , house  20 , retaining ring  30 , spring  40  and shaft driver assembly  50  may be integrally manufactured with handle  70 . 
     In the exemplary embodiment shown, handle  70  is a countered driver handle. In further exemplary embodiments, internal adapter  100  may be used with a torque driver, ratcheting driver, or other driver known in the art. 
     As illustrated in  FIG. 1 , retaining ring  30  has gap  31 . In further exemplary embodiments, retaining ring  30  may be a complete ring without gaps. 
       FIGS. 2   a  and  2   b  illustrate an exemplary embodiment of collar assembly  10 . Collar assembly  10  contains external collar base  11  and tubular sliding portion  14 , with tool receiving channel  16  extending the length of collar assembly  10 . In the exemplary embodiment shown, tubular sliding portion  14  contains securing ball apertures  15   a ,  15   b    15   c ,  15   d . Securing ball apertures  15   a ,  15   b ,  15   c ,  15   d  are equidistant and symmetrically arranged around tubular sliding portion  14 . 
     In further exemplary embodiments, tubular sliding portion  14  may contain additional securing ball apertures. While equidistant and symmetrically arranged securing ball apertures provides for greater securing and stability, in further exemplary embodiments, securing ball apertures may be asymmetrically arranged and positioned at varying distances around tubular sliding portion  14 . 
     Securing ball apertures  15   a ,  15   b ,  15   c ,  15   d  contain a contoured inner surface which creates a diameter smaller than the diameter of securing balls  60   a ,  60   b ,  60   c ,  60   d  (not shown) at the innermost edge of securing ball apertures  15   a ,  15   b ,  15   c ,  15   d . Securing balls  60   a ,  60   b ,  60   c ,  60   d  (not shown) are therefore freely rotatable within securing ball apertures  15   a ,  15   b ,  15   c ,  15   d  but may not pass through securing ball apertures  15   a ,  15   b ,  15   c ,  15   d . In further exemplary embodiments, securing ball apertures  15   a ,  15   b ,  15   c ,  15   d  may contain a lip, rim, ridge or other structure which narrows the diameter of the innermost edge of securing ball apertures  15   a ,  15   b ,  15   c ,  15   d  to prevent securing balls  60   a ,  60   b ,  60   c ,  60   d  (not shown) from passing through. 
       FIGS. 2   a  and  2   b  also show tool receiving channel  16  extending the length of collar assembly  10 . In the exemplary embodiment illustrated, tool receiving channel  16  is round tubular with a smooth surface and consistent internal diameter. In further exemplary embodiments, tool receiving channel may contain projections or grooves or may have an inconsistent internal diameter to accommodate a specifically manufactured tool. 
     The rear end of tubular sliding portion  14  contains protuberance  17  and groove  18 , both of which span the external circumference of tubular sliding portion  14 . 
       FIG. 3  is an exemplary embodiment of house  20 . As shown in  FIG. 3 , house  20  contains external house base  21  with threaded handle-engaging stem  22 . Interior collar channel  23  contains retaining ring securing protuberance  24  and extends the length of house  20 . 
       FIGS. 4   a ,  4   b  and  4   c  illustrate an exemplary embodiment of shaft driver assembly  50 . Shaft driver assembly  50  has front threaded portion  51  with tapered rear portion  52 . Front threaded portion  51  has apertures  53   a ,  53   b . Tool guiding channel  54  extends the length of shaft driver  50 . 
     As illustrated in  FIGS. 4   a ,  4   b  and  4   c , tool guiding channel  54  is primarily round tubular with a smooth internal surface at the front of shaft driver  50 . The diameter of tool guiding channel  54  decreases at chamfer  55 , creating interior lip  57 . Chamfer  55  transitions tool guiding channel  54  to a narrower diameter which includes guiding chamfers  56 . In the exemplary embodiments shown, tool guiding channel  54  contains eight double square guiding chamfers  56 . In further exemplary embodiments, guiding chamfers may be hexagonal or other configuration, and tool guiding channel  54  may contain more or fewer guiding chamfers  56  to correspond to a guiding chamfer configuration. 
     As shown in  FIGS. 4   a  and  4   c , guiding chamfers  56  do not start at the edge of chamfer  55  and have leading transition chamfer  58 . As will be illustrated in  FIGS. 8   a ,  8   b  and  8   c , the proportional distance of leading transition chamfer  58  of guiding chamfers  56  from chamfer  55  is a critical dimension. 
       FIG. 5  is a cross-sectional view of an exemplary embodiment of an assembled self-locking internal adapter  100 . As illustrated in  FIG. 5 , handle  70  has internal handle cavity  71  with front threaded portion  72 . The threads of front threaded portion  72  correspond to the threads of threaded handle-engaging stem  22  and front threaded portion  51  to secure self-locking internal adapter  100  within internal handle cavity  71 . In further exemplary embodiments, self-locking internal adapter  100  may be configured to secure to internal handle cavity  71  through any other means known in the art, including, but not limited to, adhesives, pins, locking mechanisms, brackets, screws, contours, friction-fit components, and combination of these structures and devices. In still further exemplary embodiments, self-locking internal adapter  100  may be an integral component of handle  70 . 
     In the exemplary embodiment shown, handle  70  is a standard drive handle. However, in further exemplary embodiments, handle  70  may be any handle known in the art to receive orthopedic tools, including, but not limited to, torque-limiting handles and ratcheting handles. 
     As illustrated in  FIG. 5 , external house base  21  and external collar base  11  are the only components of self-locking internal adapter  100  which project outside of handle  70 . In some exemplary embodiments, only external collar base  11  may project outside of handle  70 . Collar assembly  10  is showed slidingly engaged with house  20 , with tubular sliding portion  14  of collar assembly  10  inside interior collar channel  23  (not shown) of house  20 . 
     In the exemplary embodiment shown in  FIG. 5 , internal handle cavity  71  also contains tapered rear portion  75  which corresponds to tapered rear portion  52  of shaft driver assembly  50 . The tapered engagement of shaft driver assembly  50  with handle  70  centers internal adapter  100  and therefore a tool. 
       FIG. 6  is an exemplary embodiment of the self-locking mechanism of internal adapter  100 . As illustrated in  FIG. 6 , securing balls  60  are contained within securing ball apertures  15 , with interior collar channel  23  of house  20  creating a cover over securing ball apertures  15  to prevent securing balls  60  from disengaging securing ball apertures  15 . Contoured inner surface  19  of securing ball apertures  15  prevents securing balls  60  from slipping through securing ball apertures  15  and entering tool receiving channel  16 . 
     As shown in the exemplary embodiment illustrated in  FIG. 6 , the inner surface of interior collar channel  23  has tapered portion  25  which corresponds to securing ball apertures  15 . As spring  40  exerts outward force on collar assembly  10 , securing balls  60  in securing ball apertures  15  are forced to align with the outer-most, or narrowest, part of tapered portion  25 . Retaining ring  30 , in groove  18 , is also pushed against stop-ridge  27  of house  20 , which prevents collar assembly  10  from being forced too far outward by spring  40 . 
     As a tool would be pushed into tool receiving channel  16 , securing balls  60  freely rotate within securing ball apertures  15 , allowing the tool shaft to proceed through tool receiving channel  16  and into tool guiding channel  54  (not shown). When a tool shaft is pushed into tool receiving channel  16 , securing balls  60  are forced slightly towards the inner-most, or wider, part of tapered portion  25 . 
     If the tool is pulled out from tool receiving channel  16 , securing balls  60  are forced toward the outer-most, or narrowest, part of tapered portion  25 , so that securing balls  60  are no longer able to freely rotate. The tool shaft is therefore locked within tool receiving channel  16 . 
     To remove a tool from internal adapter  100 , external collar base  11  is pressed inward toward handle  70 . Spring  40  is compressed, and collar assembly  10  slides inward within interior collar channel  23 . Securing ball apertures  15  align with the inner-most, or widest, part of tapered portion  25 , which increases the volume of securing ball apertures  15 . Securing balls  60  are then able to freely rotated within securing ball apertures  15 , allowing the tool shaft to be pulled out of tool receiving channel  16 . 
     As illustrated in  FIG. 6 , retaining ring  30  is secured in groove  18  with spring  40  positioned between and housed within house  20  and shaft driver assembly  50 . The front portion of spring  40  rests against tubular sliding portion  14  around protuberance  17  and the rear portion of spring  40  rests against interior lip  57  of tool guiding channel  54  before transitional chamfer  55 . 
       FIG. 7  is an exemplary embodiment of tool shaft  82  for tool  80  which may be used with internal adapter  100 . At one end of tool shaft  82  is handle-engaging portion  87 . The opposite end of tool shaft  82  may contain any tool known in the art. 
     As illustrated in  FIG. 7 , groove  81  transitions tool shaft  82  to handle-engaging portion  87 , which is squared with flat surfaces  85   a ,  85   b  ( 85   c ,  85   d  not shown). In further exemplary embodiments, handle-engaging portion may be hexagonal or any other configuration known in the art. 
     Flat surfaces  85   a ,  85   b  ( 85   c ,  85   d  not shown) each have a corresponding chamfer  83   a  ( 83   b ,  83   c ,  83   d  not shown) and are separated by rounded transitions  84   a ,  84   b  ( 84   c ,  84   d  not shown), each also have a corresponding chamfer  86   a ,  86   b  ( 86   c ,  86   d  not shown). The distance from the center of groove  81  and edge of chamfer  86   a  is labeled as A. 
       FIGS. 8   a ,  8   b  and  8   c  illustrate an exemplary embodiment of internal adapter  100  engaging tool  80 . 
     As illustrated in  FIG. 8   a , tool  80  is partially inserted into internal adapter  100 . Chamfers  86  engage securing balls  60  and force them into the larger area created by tapered portion  25 . Securing balls  60  are able to freely rotate in securing ball apertures  15  (not shown) and tool shaft  82  is able to pass through tool receiving channel  16 . The distance from the center of securing balls  60  to leading transition chamfer  58  of guiding chamfers  56  is labeled as B. 
     In the exemplary embodiment shown, distance A is equal to distance B. It is critical that distances A and B are equal to provide quick and secure locking of tool shaft  82  in internal adapter  100 . 
     In  FIG. 8   b , tool shaft  82  is further in tool receiving channel  16 , with groove  81  aligned with securing balls  60  and chamfers  86  aligned with leading transition chamfer  58  (not shown) of guiding chamfers  56 . In order to fully secure tool shaft  82  in internal adapter  100 , flat surfaces  85  must properly align with guiding chamfers  56 . Securing balls  60  do not engage tool shaft  82  in this position, allowing tool shaft  82  to freely rotate within tool receiving channel  16  and be properly oriented to engage guiding chamfers  56 . 
       FIG. 8   c  illustrates tool  80  secured within internal adapter  100 . Tool shaft  82  is aligned so that handle-engaging portion  87  is aligned with guiding chamfers  56  to prevent rotational movement of tool  80  in handle  70  (not shown). Securing balls  60  are positioned along the portion of tapered surface  25  creating a smaller volume for securing ball apertures  15  and engage tool shaft  82  and prevent movement of tool  80  out of handle  70 . 
     If tool  80  is pulled outward from handle  70 , securing balls  60  are unable to rotate within securing ball apertures  15  and prevent movement of tool shaft  82 . To release tool  80 , collar assembly  10  is pushed inward toward handle  70  to compress spring  40 . Securing balls  60  are aligned with the portion of tapered surface  25  creating a larger volume for securing ball apertures  15 . Securing balls  60  are therefore able to freely rotate in securing ball apertures  15 , allowing tool shaft  82  to be removed from internal adapter  100 . 
     In the exemplary embodiment shown in  FIG. 8   c , chamfers  83  corresponding with flattened surfaces  85  correspond to and engage leading transition chamfers  58  to stabilize tool  80 .