Abstract:
There is provided a disposable scalpel having an automatically retractable blade. The blade may be secured in any of three positions: 1) an intermediated retracted position for shipping, 2) an exposed position for use and 3) a permanently locked retracted position. A spring is provided which automatically retracts the blade to the desire position.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates generally to surgical knives and more particularly to disposable scalpels. More particularly the invention relates to a disposable scalpel which may be retracted into the handle for safe disposal. Most particularly the invention relates to a disposable scalpel which is automatically retracted into the handle and is locked in the final retracted position to prevent further use.  
         [0003]     2. Related Art  
         [0004]     Surgical scalpels are special knives, the blades of which are manufactured to precise standards of high quality materials. For various reasons, it has become common to use a scalpel blade only once. Therefore there are several combination handle/replaceable blade scalpels disclosed in the art. Additionally there are now available completely disposable scalpels having inexpensive plastic handles secured to the scalpel blade.  
         [0005]     With the advent of the AIDS virus, there has now arisen much concern about transmission of disease by contact with contaminated blood. Sharp instruments, such as scalpels, which routinely come into contact with body fluids, are particularly worrisome. For this reason scalpels have been provided with removable guards to prevent contact with the blade when not in use. See for example U.S. Pat. No. 4,735,202 which discloses a scalpel in which the glade guard is provided in the form of a sleeve which is slidably mounted over the scalpel and may be locked into position over the blade when not in use. The blade guard requires two hands to position. Additionally U.S. Pat. No. 5,139,507 discloses such a scalpel whose guard may be easily moved into or out of position by the surgeon during actual surgery to prevent accidental cutting or jabbing when passing the instrument back and forth during surgery.  
         [0006]     After any “disposable” scalpel or blade is used there is still the problem of disposing of it. The scalpels or blades must be placed in special “sharps” containers to prevent janitorial or other clean up personnel from coming into contact with the contaminated instruments. Even if the blade is covered by a guard or sheath, there is a chance that the guard might become retracted or removed. Additionally, there is always the temptation to reuse such instruments, especially in poorer areas where disposal of a “perfectly good scalpel” might appear as a waste.  
         [0007]     A disposable scalpel with a retractable blade which is locked in the final retractable position is disclosed in U.S. Pat. No. 5,330,493. A spring loaded automatically retractable scalpel is disclosed in U.S. Pat. No. 5,403,337.  
         [0008]     Broadly it is an object of the present invention to provide a scalpel with a retractable blade such that the blade can be positioned for use and retracted into the handle after use.  
         [0009]     It is another object of the invention to provide a retractable blade scalpel that when fully retracted is permanently locked in the retractable position to prevent accidental reopening or reuse.  
         [0010]     It is a further object of the invention to provide a scalpel whose blade is automatically retracted into the handle.  
       SUMMARY OF THE INVENTION  
       [0011]     To achieve the above objects a scalpel is provided with a blade that is retractable into the handle. The blade may be positioned in three locations within the handle: 1) retracted for shipment, 2) exposed for use and 3) fully retracted and locked for disposal. The blade is automatically retractable into the handle by a spring which is in tension when the blade is in the first two positions and which pull the blade from the exposed to the other two positions. A means is provided to prevent the blade being retracted into the final locked position unless desired.  
         [0012]     More particularly the retractable blade scalpel comprises  
         [0013]     (a) a handle defining a chamber at the distal end;  
         [0014]     (b) a surgical blade slidably mounted within said chamber;  
         [0015]     (c) first means secured to said blade and extending externally of said chamber to move said blade from a first exposed position to a second intermediate position in said chamber and to a third position completely within said chamber;  
         [0016]     (d) second means to releasably lock said blade in said exposed position;  
         [0017]     (e) third means to releasably lock said blade in said intermediate position;  
         [0018]     (f) fourth means to permanently lock said blade in said third position; and  
         [0019]     (g) a spring secured to said blade and the inside of said handle to automatically move said blade to each of said positions when said first means is activated. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0020]      FIG. 1  is an exploded view of the preferred embodiment of the invention.  
         [0021]      FIG. 2  is an exploded view of the embodiment of  FIG. 1  shown from the opposite angle.  
         [0022]      FIG. 3  is a side view of the preferred embodiment with the cover removed and the blade in the temporary locked position as for shipping.  
         [0023]      FIG. 4  is a side view of the preferred embodiment with the cover removed and the blade in the exposed position.  
         [0024]      FIG. 5  is a side elevational view of the preferred embodiment with case removed and the blade in the permanent locked position.  
         [0025]      FIG. 6  is a view along  6 - 6  of  FIG. 5  in partial cross section. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0026]     For a detailed description of the preferred embodiment the reader is directed to the accompanying figures in which like components are given like numerals for ease of reference.  
         [0027]     Referring first to  FIGS. 1 and 2  there is shown exploded views of the preferred embodiment. The scalpel is seen to comprise a case  01  having a knurled surface  20  at the proximal end and a centimeter scale at the distal end. The knurled surface  20  is preferably an over mold of softer material to provide a better grip. On the lower edge of case  01  is a flexible tab  08  which is opposite temporary locking ramp surface  12 .  
         [0028]     A surgical blade  06  is mounted onto a blade carrier  03  by mounting plate  04 . On one side surface of the carrier  03  is permanent locking tab  11 . On the lower edge of the blade carrier  03  is a flexible member  16   a  at the end of which is a temporary locking tab  16 . Exposure locking tab  15  on flexible member  15   a  engages an exposure locking surface  22  on the interior surface of the case  01  to hold the blade  06  and carrier  03  in the exposed position. Exposure locking tab  15  extend through slot  20  for access. Flexible tab  08  on the lower edge of case  01  is in contact with temporary locking tab  16 . A spring  05  is secured to blade carrier by loop  18  which engages hook  19 . The loop  14  at the distal end of the spring is secured by pin  10   a  which engages pin receptacle  10   b  on cover  02 . On the inside surface of cover  02  there is permanent locking ramp  07  which is engaged by permanent locking tab  11  when the blade is secured in the permanently locked position (see below).  
         [0029]     Referring now to  FIG. 3 a  side elevational view of the scalpel with the cover removed is shown. This configuration has the blade retracted and releasably locked in the intermediate position as for shipping or for when the scalpel is to be passed from one person to another. In this position the temporary locking tab  16  is engaged against flexible tab  08  which prevents further retraction of the blade within the case. The spring  05  is stretched in a tension mode in this position.  
         [0030]     Referring now to  FIG. 4 a  side elevational view of the scalpel with cover removed. This configuration show the blade in the exposed position. Exposure locking tab  15  has engaged exposure locking surface  22  to hold the blade and carrier in the exposed position. The spring  05  is stretched to a further tension mode.  
         [0031]     Finally the blade and carrier are shown in the permanent locked position in  FIGS. 5 and 6 . Permanent locking tab  11  on mounting plate  04  has engaged permanent locking ramp  11  on the interior surface of the case. The tension of spring  05  has pulled the carrier  03  and blade  06  backed to this position.  
         [0032]     In use the scalpel is shipped with the blade in the intermediate retracted position with the blade fully within the case. The user presses down on the exposure locking tab  15  to move the blade forward into the exposed position and extend the spring. The exposure locking tab engages exposure locking surface  22  to hold the blade in the exposed position. If the blade needs to be temporarily retracted the user presses down on the exposure locking tab  15  which releases the carrier and allows the spring  05  in tension to retract the blade to the intermediate position. Temporary locking tab  16  engages the temporary locking ramp surface  12  to prevent the blade from being retracted further.  
         [0033]     After the scalpel has been used and is ready to be discarded the blade is permanently locked by pressing inward on flexible member  08  which in turn presses inwardly against flexible member  16   a  which releases the temporary locking tab  16  from locking ramp surface  12 . The spring  05 , still in tension, automatically retracts the blade to the permanently locked position. The user can view the carrier through viewing holes  13  on case and cover to note that it is in the locked position. The carrier cannot be disengaged from the permanent locking ramp without removing the cover and taking the scalpel apart.