Abstract:
A screw holder and torquing tool having a one-piece body with a cavity for receiving a screw in a sturdy and stable condition. The screw can be applied in stabilizing bone, and the tool can apply sufficient torque though it is of a relatively small overall size. Tangs or fingers are flexible on the tool and they flex toward and away from the cavity and they hold the screw in the tool until the screw is embedded into bone or other host object.

Description:
This invention relates to a screw holder and torquing, and more particularly, it relates to a torquing tool which can maneuver a screw or the like which has an axially rotatable drive portion and a shank end extending to both axial ends of the drive portion. 
     BACKGROUND OF THE INVENTION 
     The prior art is aware of various tools such as screw drivers, screw holders, adapters, attachments, devices, and the like for applying screws and like members to host objects. Such known tools are capable of holding a screw and then torquing it in applying the screw to the host object. The arrangement for holding the screw can include flexible fingers or the like which hold the screw until it is imbedded in the host object. Those prior art tools are commonly in two parts, one of which holds the screw and another separate part which torques the screw. 
     The present invention provides a tool which holds the screw or like work piece and also torques that work piece for applying it to the host object. This object is accomplished by trapping the screw for holding it securely so it can be accurately directed to the host object and the screw is then forcefully torqued into the host object. The tool is of a single body having two portions for those two respective functions, so it is easily and accurately be maneuvered in the application of those two functions. 
     The screw or the like useful in this invention is intended to be applied in surgical procedures. Thus the need for accuracy is crucial. The provision of a one-piece tool meets the requirements for the precision work that is in demand. 
     It is an object of this invention to provide a tool that serves the dual functions of holding the work piece and applying torque to that work piece. This is particularly useful in a work piece having two opposite ends with threads on each of the ends. Also, this tool is arranged for being both rotationally driven and for transmitting the torque for embedding the screw into the host object. 
     The tool of this invention is capable of applying a forceful torque, such as one sufficient to drive a screw into sturdy bone, during surgical procedures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a preferred embodiment of the tool of this invention, with a screw shown therein. 
     FIG. 2 is a perspective view similar to FIG. 1 but without the screw. 
     FIG. 3 is a side elevational view of the tool of FIG.  1 . 
     FIGS. 4 and 5 are respectively left hand and right hand views of FIG.  3 . 
     FIG. 6 is a top plan view of FIG.  3 . 
     FIG. 7 is a sectional view taken on a plane designated by the line  7 — 7  of FIG.  6 . 
     FIG. 8 is a side elevational view of the screw shown in FIG.  1 . 
     FIG. 9 is a sectional view similar to FIG. 7 but with the screw included therein. 
     FIG. 10 is an enlarged sectional view taken on the plane designated by the line  10 — 10  of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The tool or adapter shown herein has a body  10  which is elongated and extends along a central longitudinal axis designated A. The body is made of sturdy material capable of transmitting rotation torques about axis A and of sufficient force to drive screws, such as screw  11 , into host objects, such as bone, when used in surgery. Screw  11  is elongated and extends coaxially with axis A and has a first threaded end  12  and is shown to have a shank portion  13  disposed within a cylindrical cavity  14  in the body  10 . The shank  13  may have screw threads, such as the shown threads  16 , and the extending screw end  12  may have screw threads  17 . Threads  16  and  17  are shown to be of thread profiles different from each other, that is, they are shown to be relatively fine at  16  and relatively coarse at  17 . End  12  is arranged to be embedded into a host object, such as bone, and threads  16  can receive an unshown nut or the like, as such, the screw is useful in anchoring a rod in spine fixation. Also, screw end  12  is shown to be longer than screw end  13 . 
     Body  10  has hollow tubular portions  18  and  19 , with those two portions being integral and of one elongated piece within the structure of the body  10 , and they are availabe for cannulation, if desired. The end of the portion  18  has a flat sided exposed socket  21  and the end of the portion  19  is flat sided at  22 . Thus, a driver of any conventional rotational drive function, either manual or powered, but which is and need not be shown herein, engages the end  22  as a rotation drive input end to rotate the tool about the axis A. 
     The driven member, which in this disclosure is shown as the screw  11 , has flat sides  23  which present a screw head to be disposed in the socket  21  to mate therewith and thus be in rotation drive relationship with the rotating body  10 . As shown, the drive to what is the work piece  11  is through the flat and multi-sided surfaces, such as the hexagons shown, mating therebetween. 
     Thus, rotation drive from the tool  10  is transmitted to the work piece  11  to embed the end  12  into a host object, and the one-piece body  10  is rigid and sufficiently sturdy to accomplish that function. 
     Another feature of this invention is the holding the work piece  11  in the body  10  until the work piece is embedded as mentioned. That is, the work piece, which is shown to be the screw  11 , is restrained against movement relative to the body  10  and along the axis A. 
     In the cavity portion  18 , there are two diametrically oppositely disposed cutouts  24  extending into the wall  26  which forms the cavity  14 . That is, the wall  26  is shown to be circular and it defines the portion  18  and is of a thickness to render the tool capable of transmitting the torques required of this tool to embed the work piece  11 , as mentioned. Sectioned views in FIGS. 7,  9 , and  10  show the thickness of the wall  26 . Except for the two cutouts  24  and the output end  27  which presents the flat sides  21 , the wall  26  extends throughout the portion  18 . The end  27 , as shown, is reduced in its wall thickness compared to the wall thickness  26 , but it is disposed at the full outer diameter of the location of the wall  26  and is therefore capable of transmitting the desired high torques. Of course, a smaller flat sided opening at  21 , to accommodate a smaller screw head  23 , would present a thicker wall thickness at  21 , and that could be the full thickness of the wall  26 , for instance. 
     The two cutouts at  24  leave two diametrically disposed flats  28  extending fragmentarily on the body portion  18 . in actually, The flats  28  present walls adjacent thereto and which, as shown in FIG. 10, are irregular in their cross sectional size in their respective extents around the body portion  18 , as shown in FIG.  10 . That arrangement leaves the wall thickness  26  extending for the majority of the circumference of the body portion  18  and thus optimum torque can be transmitted by the tool and that torque can be in the magnitude of 150 in-lbs though the tool itself is small so it is useful in surgery where the tool is positioned at a patient&#39;s body without interfering with the surgeon&#39;s view of the work site. 
     Two longitudinal slits  29  are in the body  18  at each cutout area  24 , and they form an opening  30  therebetween, and thus two fingers, tangs, or strips  31  are formed at each cutout  24 . One end  32  of each tang  31  is integral with the remainder of the body portion  18  while the other end  33  of each tang  31  is free to move radially relative to the axis A. In the unstressed condition of the tangs  31 , the free end  33  is shaped to extend radially inwardly and be disposed in the cavity  14 . As such, the tangs contact the shank of the screw  11 , as seen in FIG. 9, to restrain the screw in the axial direction. The holding and release thereof is automatic, and the screw need only be inserted into the cavity  14  and the concave curves at  34  on the tang ends  33  permit the screw to slide into and out of the cavity  14 . Likewise, the screw is automatically released from the tool after there is axial force on the screw in the direction away from the tool, and that force may be applied by simply withdrawing the tool  10  away from the then embedded screw  11 . The body may be made of steel material to be sturdy and have the tangs  31  repeatedly flexible and biased inwardly in its free body position. 
     Throughout the handling of the screw as mentioned, the screw end or shank  13  is in snug contact with the wall defining the cavity  14 , as seen in FIG. 9, and thus the screw is stable with the tool. The two diametrically disposed tangs  31  hold the screw on its opposite circumferential sides to thereby hold the screw steady and secure until it is intentionally released. The extent of the tangs  31  around the circumference of the body portion  18  is less than half that circumference, thus, with the totality of the thicker wall  26  intervening between the tangs  31 , there is ample wall body for transmitting sufficient torque to the screw. 
     In a different arrangement, instead of two tangs there could be only one which extends into the cavity to hold the screw, especially where the screw shank  13  is snug in the cavity  14 . Also the tang  31  could be formed on the body portion  18  without the cutout  24 , providing there is provision for sufficient flexing of the tang or tangs on the body  18  and radially of the axis A.