Surgical instrument with collect locking and indexing system

Abstract

A surgical instrument is provided for cutting bone and other tissue. The surgical instrument includes a motor assembly, a collet, a locking nut, and an attachment. The motor assembly includes a cavity having a groove on an inner surface that corresponds to a groove on an outer surface of the collet. The corresponding grooves form an aperture when the collet is inserted into the cavity. The insertion of a pin into the aperture prevents rotation of the collet relative to the cavity. The locking nut is placed over the collet and fastened to the motor assembly to secure the collet to the motor assembly. The attachment is fastened to the collet by placing protuberances on the attachment into corresponding apertures on the collet. The consistent alignment provided by the locking and indexing system enables the motor assembly and attachment to receive alignment markings before the surgical instrument is assembled.

What is claimed is:  
     
         1 . A surgical instrument comprising: 
 a collet including a first rotation-prevention mechanism;    a motor housing operable to receive the collet, the housing including a second rotation-prevention mechanism operable to engage the first rotation-prevention mechanism to prevent rotation of the collet relative to the motor housing; and    a sleeve operable to secure the collet to the motor housing.    
     
     
         2 . The surgical instrument of  claim 1  further comprising: 
 a third rotation-prevention mechanism on the collet; and  
 an attachment having a fourth rotation-prevention mechanism operable to engage the third rotation-prevention mechanism.  
 
     
     
         3 . The surgical instrument of  claim 2  wherein one of the third and fourth rotation-prevention mechanism is a groove and the other is a protuberance.  
     
     
         4 . The locking system of  claim 1  further comprising an attachment having an engagement element for selectively securing to the collet.  
     
     
         5 . The locking system of  claim 4  wherein one of the third engagement elements is a protuberance.  
     
     
         6 . The collet of  claim 5  wherein the first fastening element is an aperture operable to receive a protuberance.  
     
     
         7 . A locking system for a surgical instrument comprising: 
 a collet having either a protuberance or aperture;    a motor assembly having the other of the protuberance or aperture corresponding to the collet, wherein the protuberance and aperture are operable to align and prevent rotation of the collet relative to the motor assembly; and    a slidable locking member operable to secure the collet to the motor assembly.    
     
     
         8 . A collet for insertion into a cavity of a surgical instrument, the collet comprising: 
 a distal portion having an opening for receiving a tool;    a first fastening element for accepting an attachment;    a proximal portion with a first alignment element for engaging a second alignment element present in the cavity, the first alignment element and the second alignment element operable to align and prevent rotation of the collet and the surgical instrument; and    a locking member rotatable about an axis of the collet, the locking member for securing the collet to the surgical instrument.