This application claims the benefit of Provisional Application No. 60/109,829 filed Nov. 25, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     The field of the invention pertains to medical scalpels and, in particular, safe methods and apparatus for replacing the scalpel blade. 
     The typical medical scalpel blade is extremely sharp and held very rigidly in the scalpel handle. Even after too dull for continued use, the blade is extremely sharp and therefore potentially dangerous when manually removed from the scalpel handle for replacement. Moreover, in pathology laboratories, in particular, the dull blade may be contaminated with a variety of unknown, but very dangerous, pathogens such as hepatitis varieties, human immunodeficiency virus (HIV), and tetanus. 
     The scalpels are widely used in hospitals, laboratories and numerous industrial sectors. In a typical application, a scalpel blade is discarded after several uses and a new blade installed onto the scalpel handle. Because of the possible contamination with pathogens, the manual process of removing the dull blade from the scalpel handle is fraught with risk. U.S. Pat. No. 4,903,390 reveals a device wherein a scalpel user can insert a scalpel in a “box” containing a mechanism. The user maneuvers the scalpel in a specified way and the blade is detached from the handle. This device is only directed to removal of the dull scalpel blade. Attachment of a new blade to the scalpel handle is not addressed. 
     With a view toward substantially eliminating the hazards associated with exchanging blades on a scalpel, the following apparatus and method has been developed. 
     SUMMARY OF THE INVENTION 
     The purpose of the new invention is to eliminate the danger involved in changing scalpel blades and to increase user working efficiency. 
     The invention comprises a modified scalpel and a blade exchanging apparatus and method whereby insertion of the scalpel blade end into the apparatus causes the dull blade to be exchanged with a new blade on the scalpel in a few seconds. 
     The quick exchange is accomplished by a cam system that opens and closes the jaws or fingers that retain the blade on the scalpel and a dispenser that positions the new blade in the open jaws or fingers just prior to closure. 
     The new invention solves the problem of detaching and attaching scalpel blades in a matter of seconds without danger to the user. With a mere twist of the wrist, the user detaches the dull blade and attaches the new blade. Also, by the design of the apparatus, contact of the dull contaminated blade with the apparatus is substantially eliminated with the exception of a “protective ring” that is removable for separate sterilization. The protective ring minimizes the likelihood of inadvertent contact of the dull blade with the apparatus. In normal use, the dull blade need not contact the apparatus, the dull blade being allowed to merely fall into a sharps container upon turning of the scalpel handle thereby opening the scalpel jaws or fingers. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates in perspective the apparatus with the protective cover removed; 
     FIG. 2 illustrates in perspective the scalpel; 
     FIG. 3 illustrates in side view a scalpel blade; 
     FIG. 4 illustrates the steps in attaching a new blade to the scalpel; 
     FIG. 5 illustrates in perspective the scalpel blade dispenser cartridge; 
     FIG. 6 illustrates in sequence the process of replacing a used blade with a new blade; 
     FIG. 7 is a cutaway view of the scalpel positioning socket of the apparatus; 
     FIG. 8 illustrates in sequence and in plan view the cartridge structure and operation; 
     FIG. 9 is a cutaway view of the cartridge box and cartridge in the apparatus; 
     FIG. 10 illustrates the parts and the mechanism in the scalpel handle; 
     FIG. 11 is a flow chart of the software for controlling the apparatus; 
     FIG. 12 is an alternative form of the clamping fingers; 
     FIG. 13 is a perspective view of a dual blade exchange apparatus; 
     FIG. 14 is an internal view of the dual blade exchange apparatus of FIG. 13; 
     FIGS. 15 a  and  15   b  are side and edge views of an alternative form of a blade extraction pin; 
     FIG. 16 is a perspective internal view of a dual socket for the dual blade exchange apparatus of FIG. 13; and 
     FIG. 17 is a side view of the dual socket of FIG. 16 with a scalpel therein. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1 the scalpel  101  is inserted with the scalpel handle extending from the inlet positioning socket  102 . The inlet positioning socket  102  only allows insertion in a particular orientation so that the clamping fingers  104  and  105  of the scalpel  101  can only be opened or closed in a horizontal direction. The inlet positioning socket  102  also limits the depth of scalpel insertion so that upon opening of the clamping fingers  104  and  105  the dull used blade  106  drops precisely into a sharps container  107  attached therebelow. 
     In FIG. 2 as shown, the clamping fingers  104  and  105  can be opened or closed by moving the two arms  108  and  109  attached to the respective clamping fingers. The two arms  108  and  109  are constrained to move in the slot  114 . The motion of the two arms  108  and  109  is controlled by twisting the scalpel handle  111  relative to the scalpel frame  110 . The internal mechanism of the scalpel  101  is further discussed below with respect to FIG.  10 . 
     When the scalpel handle  111  is turned in the direction of arrow  112 , the clamping fingers  104  and  105  open and the dull used blade drops into the sharps container  107 . When a new blade is positioned between the clamping fingers  104  and  105  as discussed below, by turning the scalpel handle  111  in the direction of arrow  113  the clamping fingers will clamp the fresh blade therebetween. Finger  105  is formed with two short pins  115  and  116  as shown in FIG.  2 . These short pins  115  and  116  fit through the slot  118  of blade  106 , as best shown in FIG. 3 to secure the position of the blade in the clamped fingers  104  and  105 . 
     FIG. 4 shows the process of clamping a new blade  117  onto the scalpel  101 . First, as discussed further below, the apparatus places the new blade in position between the clamping fingers  104  and  105 . Upon turning the handle  111  in the direction of arrow  113 , the two clamping fingers  104  and  105  close in a manner that assures full tightness on the blade  117  at the tips of the fingers. Closure is shown in the sequence of FIGS. 4.1,  4 . 2  and  4 . 3  wherein from FIG. 4.1 with the fingers  104  and  105  fully open and the pins  115  and  116  showing, the fingers first close to FIG. 4.2 wherein the tips of the fingers are shown tighter to the blade  117  than the balance of the fingers. A final slight twist to the handle  111  causes the fingers  104  and  105  to fully clamp the blade  117  as shown in FIG. 4.3. 
     As shown in FIGS. 1 and 5, new blades  130  are dispensed from a cartridge  119  placed in a cartridge box  120 . The cartridge box  120  is fixed to a sliding table  121  in turn actuated to reciprocate by a motor  122 . The motor  122  is controlled electrically by a computer based motor controller for motion of the table  121  in backward direction  123  and forward direction  124 . 
     An electromagnetic solenoid  125  is attached to the apparatus base  127  just below the open end of the cartridge box  120  and cartridge  119 . An L-shaped pin  126  is attached to the solenoid plunger for movement therewith in directions shown by arrows  128  and  129  transverse to the movement of the table  121 . Under computer control when the solenoid is moved in direction  128 , the pin  126  is inserted into the slot in the stack of new blades in the cartridge  119 . However, the pin  126  only reaches into the slot of the first blade. A key  345  is fixed to the base  127  of the apparatus. The key  345  engages a slot  346  in the solenoid plunger to prevent rotation of the plunger and misalignment of the pin  126 . 
     The opening  131  in the cartridge  119  is sized to only permit one blade to exit the cartridge through the opening in the relative direction  132 . Thus, after pin  126  is inserted into the next blade  130  in the cartridge  119 , movement of the sliding table  121  in direction  123  pulls the next blade from the cartridge  119 . 
     The step-by-step process for replacing a dull used blade with a new blade is illustrated in FIG.  6 . FIG. 6.1 shows the new apparatus absent the insertion of a scalpel. Upon insertion of a scalpel  101  with a used dull blade  106  therein as shown in FIG. 6.2 the handle  111  is rotated (arrow  112 ) to open the clamping fingers  104  and  105  as shown in FIG. 6.3 and cause the old blade to be discarded as discussed above. 
     Next, as shown in FIG. 6.4, the cartridge box  120  and cartridge  119  move toward the scalpel  101  and into alignment with pin  126 . Pin  126  extends into the next new blade  130  in the cartridge  119  in FIG. 6.5 and the cartridge box  120  and cartridge  119  retract as shown by arrow  123  in FIG. 6.6 leaving the new blade extended from the cartridge. The solenoid  125  retracts the pin  126  in FIG. 6.7 leaving the new blade  130  extended, and in FIG. 6.8 the cartridge  119  and cartridge box  120  move (arrow  124 ) toward the scalpel  101  thereby positioning the new blade  130  properly between the clamping fingers  104  and  105 . 
     The handle  111  of the scalpel  101  is rotated back  113  to close the fingers  104  and  105  and clamp the new blade  130  as shown in FIG. 6.9 and the scalpel can be withdrawn from the apparatus as shown in FIG. 6.10. The cartridge box  120  then returns to standby position as shown in FIG. 6.11. The entire sequence of FIG. 6 takes only a matter of seconds for the complete cycle avoiding any contact by the user with the dull used blade or new blade in the blade exchange process. 
     As shown in FIG. 1, a non-contact photo-electric sensor  145  detects the opening or closing of the clamping fingers  104  and  105 . Sensor  145  constantly emits a light beam that is reflected only when clamping finger  104  is directly thereunder. The receiver in sensor  145  senses the reflected light and signals the computer that an open scalpel is in place in the apparatus. 
     During the entire blade change process, the open scalpel fingers  104  and  105  are sensed by sensor  145  in FIG. 6.3 beginning the sequence of steps shown in FIGS. 6.4 through  6 . 9 . In FIG. 6.10, the sensor  145  senses closure of the clamping fingers  104  and  105 , and the computer causes the cartridge  119  and cartridge box  120  to retract in FIG.  11 . 
     Two light emitting diode (LED) lights  147  and  148  indicate to the user the working status of the apparatus. LED  147  is a green light that indicates the apparatus is ready for the user to insert a scalpel into the socket  102 . Upon rotating the scalpel handle  111 , LED  148  lights in yellow indicating to the user that the apparatus is executing the series of steps to exchange a blade and that the user should not extract the scalpel from the apparatus. When the green LED light  147  returns, after the sequence of steps through FIG. 6.9, the user can safely remove the scalpel in the step of FIG. 6.10. 
     In FIG. 7, inlet positioning socket  102  comprises an elliptical bore having opposed maxima  151  and  152  that engage a pair of complementary maxima  153  and  154  on the scalpel frame  110  shown in FIG.  2 . The scalpel frame  110  therefore is prevented from rotating when the scalpel is in the apparatus and, the handle  111  is rotated to open or close the clamping fingers  104  and  105 . The socket  102  is also formed with a stop at  150  to limit the insertion of the scalpel into the apparatus. Therefore, the scalpel socket  102  precisely positions the scalpel in the apparatus during the blade exchanging process. The socket  102  may be made a separately disposable or sterilizable item in the event the socket is contaminated by a blade or scalpel frame. 
     FIGS. 8.1 and  8 . 2  show the internal structure of the cartridge  119 . Inside the cartridge frame  157 , a spring  158  urges the blades  161  up against the front panel  162 . The spring  158  acts upon a block  156  which contacts the last blade in the cartridge blade stack. Two pins  159  and  160  align the blade stack, block  156  and spring  158 . Both pins  159  and  160  terminate at the blade  164  second to the blade to be dispensed next as best illustrated in FIG. 8.2. Therefore, the blade  130  being dispensed can pass by the pins  159  and  160  which are in the blade slots of the blades  161  remaining in the cartridge as also shown in FIG.  5 . 
     In FIG. 9 the cartridge  119  in the cartridge box  120  are shown on the table  121 . The inner dimensions of the cartridge box  120  are sized to only permit convenient sliding of the cartridge  119  in and out of the box when replacing a spent cartridge. A stop  146  positions the cartridge  119  inside the box  120  for proper alignment of the new blade to be dispensed as also shown in FIG.  1 . After a cartridge  119  is manually inserted into the box  120  and against the stop  146  a door  223  with a hinge  220  connection to the box  120  may be closed and latched with a pin  221  trapping a spring  222  between the door and the cartridge to retain the cartridge against the stop  146 . 
     In FIG. 10 the components and structure of the scalpel  101  are illustrated. FIG. 10.1 illustrates in perpendicular partial cross-sections the mechanism principally inside the frame  110  of the scalpel. As shown above, the clamping fingers  104  and  105  extend from clamping arms  108  and  109  which, in turn, extend down into the frame  110 . 
     The handle  111 , also shown in FIG. 10.2, has two pins  188  and  189  affixed thereto and extending inside the frame  110 . The handle  111  also includes an axial bore  187  extending inward at least beyond the slot  190 . Pins  188  and  189  extend through holes  181  and  182  in driving disk  180  shown in FIG. 10.3. The driving disk  180  is thereby caused to rotate with the handle  111  relative to the frame  110  (see arrows  112  and  113  in FIG.  2 ). Formed in the driving disk  180  are a pair of cam slots  183  and  184 . 
     Frame  110  illustrated in FIG. 10.4 is formed with a cylindrical bore  300  terminating with a solid covered panel  303  having the slot  114  formed in the panel as also shown in FIG.  2 . The driving disk  180  is axially located inside the frame  110  by a pair of tubes  185  and  186  illustrated in FIGS. 10.5 and  10 . 6 . The axial location is best shown in FIG. 10.1. 
     The base  193  of the frame  110  is illustrated in FIG. 10.7 wherein the upper part is formed with two screw holes  304  and  305  that match threaded holes  301  and  302  of the frame  110  (see FIG. 10.4) for attachment with screws  306  and  307  as shown in FIG. 10.1. The base  193  upper part is formed with two arcuate slots  194  and  198  through which pass the pins  188  and  189  and which allow the relative motion of the pins  188  and  189 . 
     The clamping arms  108  and  109  are shown in FIG. 10.8 having holes  201  and  202  therethrough for short pins  311  and  312  to pass through. These pins  311  and  312  rotatably affix the clamping arms  108  and  109  to the base  193  just below the slot  200 . Pin  191  tightly fits in hole  192  of base  193  and extends into slot  190  of the handle  111 . Thus, handle  111  is constrained to rotatable motion relative to frame  110  without axial movement. Since the clamping arms  108  and  109  pass through the slot  200  in the base  193  and the slot  114  in the frame  110 , they are constrained to move in a single axial plane. However, the combination of the separation distance of the pins  311  and  312  and the shape of the cam slots  183  and  184  through which the clamping arms  108  and  109  also pass forces the tips of the clamping fingers  104  and  105  to first contact as shown in FIG. 4.2 when the handle  111  is rotated to close (arrow  113 ). 
     Returning to FIGS. 1 and 7, FIG. 7.1 illustrates an optional snap-on protective cap  102 A for the outside of socket  102 . The protective cap is of throw-away plastic or sterilizeable metal and easily replaceable. The protective cap  102 A intercepts inadvertent contact of the used dull and contaminated blade with the outside of the socket  102  thereby greatly reducing the likelihood of contamination of the apparatus. The new apparatus provides exchange of scalpel blades without contact of the blades and therefore under exceptionally sterile conditions. 
     A protective ring  340  may also be installed with screws  341  and  342  to protect against dull blades that do not fall directly into the sharps container  107 . This ring  340  may also be either sterilizeable or throw-away. 
     FIG. 11 illustrates a flow diagram for the microprocessor control of the process and apparatus. In prototype testing, blade exchange is accomplished by a mere “twist of the wrist” for a few seconds while the yellow light is observed on the apparatus. 
     Under some conditions of use, blood and other fluids may cause a blade to stick to one clamping finger as the fingers open. In FIG. 12, an alternative form of the clamping finger pins is illustrated. The alternative form of the pins is directed to assuring that a dull contaminated blade will always dislodge from the pins and drop from the scalpel clamping fingers when they open. The pin shapes as shown are specifically formed to secure the blade from any relative movement with respect to the clamping fingers when closed. 
     In FIG. 12, clamping finger  404  includes a conical topped pin  415  near the tip and a conical topped pin  416  near its base. Both conical topped pins  415  and  416  have cylindrical shoulders  419  and  420  which form lands that engage the slot  118  of a blade  106  (see FIG.  3 ). With the clamping fingers  404  and  405  closed, the blade  106  engages the shoulders  419  and  420  thereby preventing movement of the blade relative to the fingers. 
     When the clamping fingers  404  and  405  open, the blade  106  is restrained between guides  506 A and  506 B as further described below with reference to FIG.  16 . The guides ensure separation and detachment of a dull blade from pins  415  and  416 . 
     FIG. 13 depicts a dual blade exchange version of the apparatus. The positioning socket comprises two positioning sockets  502 A and  502 B in a vertical arrangement. The sockets  502 A and  502 B are identical to permit a scalpel to be inserted into either of the sockets. One sharps container  507  is situated below to collect spent blades regardless of which socket  502 A and  502 B is selected. The green  547  and yellow  548  lights perform the same “ready” or “in operation” function as above but for either socket  502 A or  502 B in the dual version of the apparatus. 
     In FIG. 13, the power cord  533  and plug  535  are depicted to emphasize that, as an alternative, the plug  535  may be an integral step down low voltage supply for the apparatus. In some environments, such as an operating room, a low voltage supply is desirable where electrically conductive fluids, such as ordinary water and blood, may be splashed during major surgery. 
     Internally, the dual version of the apparatus includes upper  520 A and lower  520 B cartridge boxes having cartridges  519 A and  519 B located therein. The cartridges  519 A and  519 B may be filled with identical blades, thus doubling the supply, or the blades in cartridge  519 A may differ in size or style from the blades in cartridge  519 B. 
     The cartridge boxes  520 A and  520 B are stacked as shown and fastened to a sliding table in turn fastened to a slider  521 A for reciprocation in a channel  521 B. The channel  521 B in turn is mounted on a base  527  as above. 
     Also mounted on the base  527  are dual solenoids  525 A and  525 B. Each solenoid  525 A or  525 B is electrically coordinated with the two positioning sockets  502 A or  502 B to provide solenoidal actuation only for the socket into which a scalpel has been inserted. The solenoids  525 A and  525 B extend the plates  526 A and  526 B in coordination with the socket in use to extract a blade from either cartridge  519 A or cartridge  519 B. Although shown with two cartridge boxes  520 A and  520 B, the apparatus may be constructed three or more high in cartridge boxes  520  and solenoids  525 . 
     FIGS. 15A and 15B further depict in detail the alternate plates  526 A and  526 B of the dual version of the apparatus. Either plate  526 A or  526 B in FIG. 14 is affixed by any suitable fastening means at  545  to the corresponding solenoid plunger. The tip is insertable in the slot  118  of a blade  106  or  130  but limited to the thickness  537  of a blade by the stop  549  on the plate  526 . The stop  549  contacts the blade  130  to prevent penetration further into the stack of blades  161  further in the cartridge. 
     Illustrated in FIGS. 16 and 17 is a detail of a device for assuring detachment of the spent blade  506  from the scalpel  501 . Insertion of a scalpel frame into the upper  502 A or lower  502 B socket positions a small portion of the spent blade  506  between a pair of guides  506 A and  506 B adjacent the fingers  104  and  105 . The guides  506 A and  506 B are fastened  503  to the dual socket  502 . With insertion, twisting of the scalpel handle  111  causes fingers  104  and  105  to open and guides  506 A and  506 B assure the spent blade  506  is dislodged from the fingers and drops into sharps container  507 .
A modified scalpel and blade exchanging apparatus and method whereby insertion of the scalpel blade ( 106) end into the apparatus and turning of the scalpel handle ( 111) causes the dull or spent blade to be exchanged with a new blade ( 130) on the scalpel ( 101) in a few seconds. The quick exchange is accomplished by a cam system ( 183, 184) that opens and closes the jaws or fingers ( 104, 105) that retain the blade on the scalpel and a dispenser ( 119) that positions the new blade in the open jaws or fingers just prior to closure. The new invention solves the problem of detaching and attaching scalpel blades in a matter of seconds without danger to the user. With a mere twist of the wrist, the user detaches the dull blade and attaches the new blade, the dull blade dropping into a sharps container ( 107) upon detachment. Also, by the design of the apparatus, contact of the dull contaminated blade with the apparatus is substantially eliminated with the exception of a protective cap ( 102 A), protective ring ( 340) or disposable socket ( 102) that are removable for separate sterilization or disposal. In the preferred embodiments, the new blades are dispensed from a cartridge ( 119) and multiple cartridges may be provided for the selection of differing blades.