Patent Publication Number: US-6669702-B2

Title: Modular tool connection assembly

Description:
This application claims the benefit of Provisional application Ser. No. 60/267,889, filed Feb. 10, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention generally relates to modular connections useful in Orthopedic and Industrial tool design to create a quick connect and disconnect function while maintaining a rigid connection. Of particular interest are modular tool junctions wherein the interface gives the user a sensation or feeling similar to a one piece construction. It is necessary, for instance, in some surgical procedures for a surgeon who is using a handled instrument (such as a screw driver, a tap, a reamer, or a countersink) to feel the quality of the bone when he is using the instrument (such as drilling or tapping the bone or screwing something into it). This need for sensation during the surgery has forced some manufactures of surgical products to manufacture a one piece instrument integral with the handle. When sensation is not necessary, companies often provide surgeons with a modular handle with several different tools that interface into it. With the rising costs of healthcare, companies are searching for solutions to reduce their cost for necessary surgical instrumentation while trying not to compromise the surgeon&#39;s sensation requirements. To meet this need, one idea was presented using a tool collet that was integrated with a handle. The surgeon places the shaft of a tool into the collet and then activates the collet using a threaded sleeve. The threaded sleeve when turned closes the collet which in turn creates a solid connection to the tool shaft. The collet functions well, however it can be clumsy and rather a slow method of interchanging the tools. These factors create additional surgical time which is unacceptable for containment of cost. 
     It is the primary aim of the present invention to provide a modular connection for surgical and industrial tool designs which is quick to connect. There is also a need to create a connection that is rigid. There is a further need to create a connection that is reversible. There is still further need for a tool connection that consists of mating tapers. There is yet still a further need for a tool connection with mating tapers whose connection force is limited by a spring. 
     SUMMARY OF THE INVENTION 
     To accomplish these objectives, the invention comprises a housing which defines the main axis of assembly with a linear bore for containing the components of the assembly. The housing contains a connector component presenting a first taper portion. The connector is retained in the linear bore of the housing with a spring interposed between the connector and the housing. A tool containing a second taper portion is placed in axial engagement with the first taper causing the components to be securely connected. The spring limits the force applied between the taper portions allowing them to be disconnected easily. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows an exploded isometric view of an un-assembled modular tool connection assembly embodying the present invention. 
     FIG. 2 Shows a cross section of a side view of the un-assembled modular tool connection of FIG.  1 . 
     FIG. 3 shows a blown up cross section of the side view of the un-assembled modular tool connection shown in FIG.  2 . 
     FIG. 4 shows a cross section of a side view of the assembled modular tool connection assembly embodying the present invention. 
     FIG. 5 shows a blown up cross section of the side view of the assembled modular tool connection show in FIG.  4 . 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     One preferred embodiment of the present invention is displayed in FIGS. 1-5. Generally shown in FIG. 1 is an exploded view of the assembly comprising of a connector  10 , a spring  30 , a housing  40 , and a retaining pin  35 . These components are shown in a pre-assembled orientation as seen in FIGS. 2-5. The connector  10  is pre-assembled in the bore  45  of the housing  40  and restrained with the retaining pin  35 . The spring  30  is also pre-assembled interpositionally therebetween. The spring  30  rests in the bore  45  of the housing  40  and is centered in a second bore  15  which is located in the connector  10 . In cross-section, the connector  10  also contains a first taper  20  useful for mating with a second taper  55  on the tool  50 . An abuttement  56  prevents the tool  50  from entering into the bore  45  to an extent that the connector component would bottom out against the retainer  35 , thus insuring a consistent removal force. 
     A complete assembly  70  is shown in FIGS. 4-5 wherein the spring  30  is shown in a compressed state and the mating taper junction  60  is shown. The spring  30  acts as a force limiter during the assembly process not allowing the user to place too much force into the mating taper junction  60 . Because the assembly force is limited, it is easy to remove the tapers  20 ,  55  on disassembly simply by pulling them apart. The tapers  20 ,  55  also act to center the junction  60  and can be in the form of a morse taper which is commonly used for separable junctions. Depending on the application, it may be necessary to apply torque or axial force through this junction  60  which can be achieved by adding additional retention mechanisms which are not shown. For example other medical instrument retention mechanisms such as the small, mini, or large AO connection the Zimmer Hall, or a bayonet system may be combined with the present invention to create an extremely stable modular junction. These retention mechanisms may also hold the spring  30  in a compressed state similar to that shown in FIGS. 4.5 when assembled. This will allow the spring to retain a light force in the taper junction  60  while in the assembled state. This tension can be useful for ensuring that the tapers  20 ,  55  remain rigid during use of the assembly  70 . The housing  40  can also be a part of a handle assembly of a component of another instrument. What is important to the instant inventor is the use of the force limited junction to create stability in a modular instrument construct so that there is no play between the junctions. 
     Although the invention has been described with reference to preferred embodiments thereof, it is evident to those of skill in the art that various modifications and improvements may be made without departing from the spirit and scope of the invention as defined by the appended claims.