Abstract:
The present invention is a highly stable gear drive adapter featuring a stabilized drive assembly. The drive assembly includes a drive shaft connected to a gear holder assembly, which couples to a gear shaft assembly, which in turn couples to a tool adapter. Each component of the drive assembly stabilizes or is stabilized by another component. A cover aperture and a drive shaft bearing stabilize the drive shaft laterally. Additionally, an interface between a polygonal band on the surface of the drive shaft and a polygonal aperture in the gear holder assembly also stabilizes the drive shaft laterally. A retaining ring and a shaft stop stabilize the drive shaft axially. The gear shaft assembly includes two gear shaft bearings laterally stabilizing a gear shaft and a gear shaft channel that contains the drive shaft bearing. A tool adapter bearing stabilizes the tool adapter.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of and claims priority to U.S. patent application Ser. No. 14/051,693, filed on Oct. 11, 2013, which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to the field of medical drivers, and more specifically to a gear-driver adapter for medical tools. 
         [0004]    2. Description of the Related Art 
         [0005]    Drivers are handles used to turn medical implants, screws or other components during surgery. Typical drivers require a complete turn of the handle to complete one turn of the tool shaft. It is a problem known in the art that this motion places significant stress on the surgeon&#39;s hand, wrist and arm. 
         [0006]    Gear-drivers are mechanisms known in the art that allow surgeons to turn a tool shaft using fewer handle rotations, as expressed by the ratio of the number turns of a tool shaft to the number of actual turns of a handle required by a surgeon. For example, some gear-drivers have a 2:1 gear ratio, requiring only a single turn of the driver to complete 2 turns of the tool shaft. Gear-drivers therefore allow surgeons and patients to spend less time in surgery, and decrease the amount of physical stress on the surgeon. 
         [0007]    Another problem known in the art is that subjecting a gear-driver to sudden bursts of torque can destabilize components and decrease the precision of inputs and outputs. Destabilization of components has caused gear drivers to fail during surgery, as documented by FDA incident reports. A second problem with gear-drivers is that both straight drivers and gear-drivers are required to complete a single drive task. A surgeon must therefore manage multiple tools during surgery. 
       SUMMARY OF THE INVENTION 
       [0008]    One embodiment of the present invention is a highly stable gear drive adapter apparatus including a stabilized drive assembly for transmitting a force. The stabilized drive assembly includes a drive shaft stabilized by a drive shaft bearing, a stabilizing gear holder assembly, a stabilized gear shaft assembly and a tool adapter stabilized by a tool adapter bearing. 
         [0009]    Another embodiment of the present invention is a system for stabilizing a drive assembly for a highly stable gear drive adapter including a drive shaft bearing, a tool adapter bearing, a retaining ring and a stabilizing gear holder assembly. 
         [0010]    Another embodiment of the present invention is a highly stable gear drive adapter apparatus including a stabilized drive assembly for transmitting a force. The stabilized drive assembly includes a drive shaft stabilized by a drive shaft bearing, a stabilizing gear holder assembly, a stabilized gear shaft assembly and a tool adapter stabilized by a tool adapter bearing. The drive shaft includes a retaining ring groove housing a stabilizing retaining ring. The stabilizing gear holder assembly includes a front stabilizing plate, a back stabilizing plate, a plurality of spacers and a plurality of gears. The stabilized gear shaft assembly includes a gear shaft supported at two points by two gear shaft bearings. The gear shaft has a gear shaft channel that contains at least one drive shaft bearing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIGS. 1   a  and  1   b  illustrate a perspective view and a side view, respectively, of an exemplary gear-driver adapter. 
           [0012]      FIGS. 2   a  and  2   b  illustrate an exploded view and a cross-sectional view of gear-driver adapter. 
           [0013]      FIG. 3  illustrates a front perspective view of a drive shaft. 
           [0014]      FIGS. 4   a  and  4   b  illustrate a front perspective view and a back perspective view, respectively, of a gear holder assembly. 
           [0015]      FIG. 5  illustrates a back perspective view of a gear body. 
           [0016]      FIG. 6  illustrates a perspective view of an exemplary gear-driver adapter system in use with an interchangeable handle and a surgical instrument. 
       
    
    
     TERMS OF ART 
       [0017]    As used herein, the term “adapter” refers to a component of an orthopedic tool handle that engages a tool. 
         [0018]    As used herein, the term “gear” refers to any rotating structure having teeth that interact or mesh with another component to transmit torque or motion. 
         [0019]    As used herein, the term “stabilize” or “stabilizing” refers to the control of non-utilitarian movement of a component. 
       DETAILED DESCRIPTION OF INVENTION 
       [0020]      FIGS. 1   a  and  1   b  illustrate a perspective view and a side view, respectively, of an exemplary gear-driver adapter  100 . 
         [0021]      FIGS. 2   a  and  2   b  illustrate an exploded view and a cross-sectional view of gear-driver adapter  100 . Gear-driver adapter  100  includes a back end having a cover  10 , a drive shaft  20 , a gear holder assembly  30 , a retaining ring  40 , a drive shaft bearing  45 , a gear shaft assembly  50 , a gear body  60 , a tool adapter  70  and a gripping handle  80  at a front end. Drive shaft  20 , gear holder assembly  30 , gear shaft assembly  50  and tool adapter  70  form a stabilized drive assembly. 
         [0022]    Cover  10  includes a grooved outer cover surface  11 , a threaded inner cover surface  12  and a cover aperture  13 . Grooved outer surface  11  may contain any configuration or variety of grooves that facilitate assembly. Threaded inner cover surface  12  provides a threaded connection between cover  10  and gear body  60  for assembly. Cover aperture  13  is sized to accept and provide support to drive shaft  20 . 
         [0023]    Drive shaft  20  includes handle interface  21 , a handle groove  22 , a shaft stop  23 , a retaining ring groove  24 , a polygonal band  25  and a bearing interface  26 . In the embodiment shown, handle interface  21  has a square configuration with four flattened surfaces separated by rounded transitions for attachment to a square driver handle. Other embodiments may have a hexagonal, triangular, or any other configuration capable of attaching to a driver handle known in the art. Handle groove  22  can also serve to secure drive shaft  20  to a given driver handle. 
         [0024]    When gear-driver adapter  100  is fully assembled, shaft stop  23  and retaining ring groove  24  are found backward and forward, respectively, of drive shaft aperture  37  in gear holder assembly  30 . Shaft stop  23  prevents drive shaft  20  from moving forward along its axis. Retaining ring  40 , located in retaining ring groove  24 , prevents drive shaft  20  from moving backward along its axis. Polygonal band  25  is located within drive shaft aperture  37  in gear holder assembly  30 . While the exemplary embodiment of polygonal band  25  shows a hexagonal configuration with six flattened surfaces separated by rounded transitions, other embodiments may have a square, triangular, or any other polygonal configuration. 
         [0025]    Bearing interface  26 , located at the front end of drive shaft  20 , fits together with drive shaft bearing  45  to support drive shaft  20  during use. Because drive shaft  20  has support from cover  10 , gear holder assembly  30  and drive shaft bearing  45 , it is more stable and less likely to laterally deflect during torque input. 
         [0026]    Gear holder assembly  30  includes a back plate  31 , a front plate  32 , multiple spacers  33 , multiple planet gears  34  having planet gear teeth  35 , multiple gear axes  36 , drive shaft aperture  37  and sterilant apertures  38 . In use, gear holder assembly  30  transmits torque or motion from drive shaft  20  to gear shaft  51 . 
         [0027]    Spacers  33  connect back plate  31  and front plate  32 . While the exemplary embodiment shown has three spacers  33 , other embodiments may include spacers ranging in number from two to as many as can fit between planet gears  34 . Spacers  33  are located equidistantly within the outer perimeters of back plate  31  and front plate  32 , but do not extend beyond these edges. Each spacer  33  is located between two planet gears  34 . 
         [0028]    Each planet gear  34  includes a gear axis  36 . In the exemplary embodiment, gear axes  36  are pin-style axes. However, in other embodiments gear axes  36  are any structure or device known in the art to rotationally secure gears  34  within gear holder assembly  30 . Because both back plate  31  and front plate  32  provide support to gear axes  36  during use, planet gears  34  have a decreased likelihood of misalignment over the life of gear-driver adapter  100 . 
         [0029]    Drive shaft aperture  37  is centrally located in back plate  31 , and has an inner diameter just larger than the outer diameter of polygonal band  25  of drive shaft  20  to permit insertion of drive shaft  20  within drive shaft aperture  37 . The exemplary embodiment of drive shaft aperture  37  shows a hexagonal configuration with six flattened surfaces separated by rounded transitions, corresponding to the exemplary embodiment of polygonal band  25 . Other embodiments may have a square, triangular, or any other polygonal configuration in order to accommodate other embodiments of polygonal band  25 . 
         [0030]    Sterilant apertures  38  are located in back plate  31 . These sterilant apertures  38  allow a fluid sterilant to enter into the interior of gear-driver adapter  100  and sterilize it. While the exemplary embodiment includes six sterilant apertures  38 , other embodiments may include more or fewer sterilant apertures  38 . 
         [0031]    Retaining ring  40  interfaces with retaining ring groove  24  to prevent drive shaft  20  from moving backward along its axis. In the exemplary embodiment, retaining ring  40  is a tapered section retaining ring. Other embodiments may utilize constant section retaining rings or spiral retaining rings. 
         [0032]    Drive shaft bearing  45  fits together with bearing interface  26  to support drive shaft  20  during use. Because the front end of drive shaft  20  has support from drive shaft bearing  45 , it is more stable and less likely to laterally deflect during torque input. In the exemplary embodiment, drive shaft bearing  45  is a rolling-element bearing such as, but not limited to, a ball bearing or a cylinder bearing. Other embodiments may utilize plain bearings such as, but not limited to, a bushing bearing or a two-piece bearing. 
         [0033]    Gear shaft assembly  50  includes gear shaft  51 , gear shaft teeth  52 , gear shaft threading  53 , gear shaft bearings  54   a  and  54   b  and gear shaft channel  55 . Gear shaft  51  transmits torque or motion from gear holder assembly  30  to tool adapter  70 . 
         [0034]    Gear shaft teeth  52  surround the outer back surface of gear shaft  51 . The size of gear shaft teeth  52  corresponds to the size of planet gear teeth  35 , allowing gear shaft teeth  52  and planet gear teeth  35  to intermesh. Gear shaft threading  53  surrounds the outer front surface of gear shaft  51  and permits a secure coupling between gear shaft  51  and tool adapter  70 . 
         [0035]    Gear shaft bearings  54   a  and  54   b  are located in front of gear shaft teeth  52  and behind gear shaft threading  53 , respectively. Gear shaft bearings  54   a  and  54   b  support gear shaft  51  within gear-driver adapter  100  and ensure smooth rotation during use. Gear shaft bearings  54   a  and  54   b  also prevent lateral deflection that may cause gear shaft  51  to misalign with gear holder assembly  30  or tool adapter  70 . In the exemplary embodiment, gear shaft bearings  54   a  and  54   b  are rolling-element bearings such as, but not limited to, a ball bearing or a cylinder bearing. Other embodiments may utilize plain bearings such as, but not limited to, a bushing bearing or a two-piece bearing. 
         [0036]    Gear shaft channel  55  extends from a back end of gear shaft  51  to a front end of gear shaft  51 . The diameter of gear shaft channel  55  approximately matches the outer diameter of drive shaft bearing  45 , allowing positioning of drive shaft bearing  45 , and by extension drive shaft  20 , within gear shaft  51 . 
         [0037]    Gear body  60  includes gear body teeth  61 , threaded back gear body surface  62 , threaded front gear body surface  63  and gear body channel  64 . Gear body teeth  61  surround the inner back surface of gear body  60 . The size of gear body teeth  61  corresponds to the size of planet gear teeth  35 , allowing gear body teeth  61  and planet gear teeth  35  to intermesh. 
         [0038]    In the exemplary embodiment shown, the inner surface of gear body  60 , the outer surfaces of planet gears  34  and the outer surface of gear shaft  51  act as a planetary gearing system in which the inner surface of gear body  60  is an annulus or ring, gear holder assembly  30  is a planet carrier for planet gears  34  and the outer surface of gear shaft  51  is the central, or sun, gear. In the planetary gearing system described, the inner surface of gear body  60 , or the annulus or ring, holds stationary, with input rotation provided by planet gears  34 . The outer surface of gear shaft  51 , or sun gear, produces the output rotation, which is communicated to tool adapter  70  through its coupling. 
         [0039]    In the exemplary embodiment described, this arrangement results in a fixed gear ratio, meaning the outer surface of gear shaft  51  is the central, or the sun gear, rotates a given number of times for each rotation of planet gears  34 . In further exemplary embodiments, gear body  60 , planet gears  34  and gear shaft  51  may be of different sizes or have different numbers of teeth. In still further exemplary embodiments, gear holder assembly  30  may include more or fewer planet gears  34 . The gear ratio of gear-drive adapter  100  may be increased or decreased by modifying these factors. 
         [0040]    Threaded back gear body surface  62  couples gear body  60  to cover  10  through threaded inner cover surface  12 . Threaded front gear body surface  63  couples gear body  60  to gripping handle  80 . However, in further exemplary embodiments, coupling gear body  60  to cover  10  and/or gripping handle  80  may occur through any method known in the art, including clips, snap-fits, contours, and other structures. Gear body channel  64  supports gear shaft bearings  54   a  and  54   b.    
         [0041]    Tool adapter  70  includes tool adapter bearing  71  and tool adapter aperture  72 . Tool adapter  70  is an internal adapter having a release collar, as known in the art. However, further exemplary embodiments may use a different tool adapter known in the art. Tool adapter bearing  71  supports tool adapter  70  during torque output. In the exemplary embodiment, tool adapter bearing  71  is a rolling-element bearing such as, but not limited to, a ball bearing or a cylinder bearing. Other embodiments may utilize plain bearings such as, but not limited to, a bushing bearing or a two-piece bearing. Because tool adapter  70  has support from tool adapter bearing  71 , it is more stable and less likely to laterally deflect during torque output. Tool adapter aperture  72  may be configured to receive any tool known in the art. 
         [0042]    Gripping handle  80  includes contoured outer gripping handle surface  81 , threaded inner gripping handle surface  82  and gripping handle aperture  83 . In the exemplary embodiment, outer gripping handle surface  81  is a contoured surface. In further exemplary embodiments, outer gripping handle surface  81  may contain any variety of contours and be made of any material which facilitates gripping and provides a comfortable and stable grip. Threaded inner gripping handle surface  82  couples gripping handle  80  to gear body  60 . Gripping handle aperture  83  permits passage of tool adapter aperture  72  during assembly. 
         [0043]      FIG. 3  illustrates a front perspective view of drive shaft  20 . 
         [0044]      FIGS. 4   a  and  4   b  illustrate a front perspective view and a back perspective view, respectively, of gear holder assembly  30 . Planet gears  34  and gear axes  36  are not shown in  FIG. 4   b  for clarity. 
         [0045]      FIG. 5  illustrates a back perspective view of gear body  60 . 
         [0046]      FIG. 6  illustrates a perspective view of an exemplary gear-driver adapter system  200  in use with an interchangeable handle  202  and a surgical instrument  204 . Gear-driver adapter system  200  features interchangeable handle  202 , which is adapted to connect securely to gear-driver adapter  100 . In the embodiment shown, interchangeable handle  202  and gear-driver adapter  100  have corresponding mechanical engagements. In the embodiment shown, the engagements are on drive shaft  20  and the interior surface of component of interchangeable handle  202  (not shown). The mechanical engagements may conform to specifications for the corresponding geometry. In the embodiment shown, drive shaft  20  interfaces with interchangeable handle  202  at handle interface  21 . Surgical tool  204  attaches at the front portion of gear-driver adapter  100  at tool adapter aperture  72 . 
         [0047]    In the exemplary embodiment, interchangeable handle  202  may be rotated in either direction, resulting in rotational movement of surgical tool  204  in the same direction. In further exemplary embodiments, rotation of interchangeable handle  202  may be turned in only one direction. In still further exemplary embodiments, interchangeable handle  202  may be rotated in either direction while surgical tool  204  is configured to turn in only one direction. 
         [0048]    In the exemplary embodiment shown, gear-driver adapter  100  operates at a fixed gear ratio. In one embodiment, gear-driver adapter  100  operates at a 1:1 gear ratio, and a single turn of interchangeable handle  202  causes a single turn of surgical tool  204 . In another embodiment, gear-driver adapter  100  operates at a 3:1 gear ratio, and a single turn of interchangeable handle  202  causes three complete turns of surgical tool  204 . 
         [0049]    In further exemplary embodiments, gear-driver adapter  100  may be configured to operate at any gear ratio, although the range of gear ratios that may be used with gear-driver adapter  100  may be limited by reasonable size constraints of interchangeable handle  202 , gear-driver adapter  100  and surgical tool  204 . In most exemplary embodiments, gear-driver adapter  100  may be configured to operate at gear ratios between 1:5 and 8:1, where a 1:5 ratio provides one complete rotation of surgical tool  204  for every five rotations of interchangeable handle  202  and an 8:1 ratio provides eight complete rotations of surgical tool  204  for every one rotation of interchangeable handle  202 . 
         [0050]    It will be understood that many additional changes in the details, materials, procedures and arrangement of parts, which have been herein described and illustrated to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. 
         [0051]    It should be further understood that the drawings are not necessarily to scale; instead, emphasis has been placed upon illustrating the principles of the invention. Moreover, the term “approximately” as used herein may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related.