Abstract:
A surgical scalpel assembly includes a blade carrier, a blade, a protective sleeve and a handle. The blade carrier has a number of notches and the protective sleeve has a depending tooth. The user positions the sleeve relative to the blade carrier and/or the handle by positioning the tooth to engage the notches. The blade carrier, blade, and protective sleeve are pre-assembled as a cartridge. A high volume yet safe method of assembly is also described.

Description:
RELATED APPLICATION  
       [0001]     This application claims priority under 35 U.S.C. § 119(e) based on provisional application No. 60/663,375 filed Mar. 18, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention pertains to surgical scalpels, and in particular, such scalpels of the type that have a protective shield or the like whereby the blade can be selectively exposed or covered in use, then disposed of.  
         [0003]     Many scalpels of this type are known, such as described in the following U.S. patents and U.S. published applications:  
                                           3,793,726   5,330,494   5,527,329       5,868,771   5,919,201   5,938,676       5,938,675     941,892   6,053,929       6,626,925   2004/0243161   D490,153                  
 
         [0004]     The general concept of a blade carrier attachable to a handle and to the blade itself, with an integral or separate protective sleeve or guide for the blade that is moveable to at least two positions, is well known. Moreover, the further refinement of the blade carrier with associated blade being detachable from the handle for disposal, while recovering the handle for sterilization and reuse is also known. U.S. Pat. No. 5,919,201 embodies this refinement in a combination of a handle, a cartridge removably mounted to the handle, a blade attached to a blade holder in the cartridge and a shield mounted on the blade holder.  
         [0005]     The known devices may all perform their intended function, but none exhibits an ideal combination of low cost components and manufacturability, with simplicity yet reliability of use.  
       SUMMARY OF THE INVENTION  
       [0006]     A significantly improved combination of such desirable attributes is achieved with the present invention. In general aspect, the invention comprises a blade carrier having a lower edge defining a plurality of notches, a handle having a notch on the lower edge, and a protective sleeve having a depending tooth for engaging the notches on the carrier and the handle. The user slides the sleeve and positions the tooth for selectively establishing and reestablishing at least three detent conditions of (1) pre-assembly, (2) assembly to complete attachment of the handle to the carrier, and (3) a cutting condition.  
         [0007]     Another aspect of the invention is directed to a high volume yet safe assembly technique for the carrier, blade, and sleeve as a cartridge or the like for later attachment to the handle.  
         [0008]     Those familiar with this field of endeavor will appreciate that one or more of advantages of the preferred embodiment include: (1) minimized waste by minimizing of the amount of material to be disposed; (2) lower tooling cost by locating of all the blade and carrier retention features on the same side as well as minimizing the number of tolerance sensitive features; (3) independent optimization of the shape and weight of the reusable handle; (4) prevention of accidental reuse of contaminated blade; and (5) easy reclaiming of material used for the blade as well as blade carrier and protection sleeve. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The preferred embodiments will be described with reference to the accompanying drawings, in which:  
         [0010]      FIG. 1  is an exploded view of the three main components of blade, blade carrier, and protective sleeve that are ultimately assembled with a handle to form the scalpel;  
         [0011]      FIG. 2  is an elevation view of the three components shown in  FIG. 1 , pre-assembled as a cartridge before attachment to a handle;  
         [0012]      FIG. 3  is an enlarged view of the blade carrier component, showing one suitable pattern of three notches on the bottom edge;  
         [0013]      FIG. 4  is an exploded view of the handle and the pre-assembly cartridge of  FIG. 2 , in position for attachment together;  
         [0014]      FIG. 5  is an elevation view, partly in section, of the assembled scalpel in a storage condition;  
         [0015]      FIG. 6  is view similar to  FIG. 5 , showing the sleeve retracted to expose the blade for use during surgery;  
         [0016]      FIG. 7  is a view similar to  FIG. 6 , showing the sleeve displaced fully forward, to cover the blade permanently and permit detachment of the cartridge from the handle for disposal;  
         [0017]      FIG. 8  is an elevation view corresponding to  FIG. 2 , of an alternative embodiment wherein the blade has a different shape, the blade carrier has a different notch pattern, and the sleeve has a different support for the tooth;  
         [0018]      FIG. 9  is a view similar to  FIG. 5 , partially in longitudinal section, showing the scalpel with the pre-assembly cartridge of  FIG. 8  in the storage condition;  
         [0019]      FIG. 10  is a perspective view of an alternative embodiment of the sleeve of  FIG. 1  wherein the tooth has a different shape and is located at a different position on the sleeve;  
         [0020]      FIG. 11   a  is a longitudinal section view of the embodiment of  FIG. 10 ;  
         [0021]      FIG. 11   b  is a cross-sectional view of the proximal end of the embodiment of  FIG. 10 ;  
         [0022]      FIG. 12  is a longitudinal view, partially in section, of  FIG. 9  where the sleeve is fully forward in the disposal condition;  
         [0023]      FIG. 13  is a side view of an alternative embodiment of the elongated blade assembly wherein the means for attaching the blade to the blade carrier is different; and  
         [0024]      FIGS. 14A-14E  illustrate the preferred method for assembling the scalpel of the embodiment shown in  FIGS. 8 and 9 . 
     
    
     DETAILED DESCRIPTION  
       [0025]     The present invention is directed to a safety scalpel assembly to be mounted on a customized reusable handle, preferably of stainless steel. As illustrated in  FIG. 1 , the pre-assembly or cartridge of the safety scalpel comprises three components: sleeve  16 , blade carrier  14 , and blade  12 .  FIG. 2  illustrates the sleeve  16 , the blade carrier  14  and blade  12  (hidden from view) pre-assembled as a cartridge  22 . The blade  12  may be any number of different shapes and sizes.  
         [0026]     It is an aspect of the invention that blade carrier  14  and sleeve  16  are manufactured from durable materials able to withstand repeated sterilization by, typically, the fabricator. In one preferred embodiment the blade carrier  14  is injection molded using a suitable thermoplastic material. It is also preferred that sleeve  16  is transparent thermoplastic material to allow post-assembly visual inspection and identification of the blade  12 . In another embodiment sleeve  16  can be non-transparent. As best seen in  FIGS. 4 and 10 , sleeve  16  is substantially tubular with two open ends (a proximal end  16   a  and a distal end  16   b ), and a closed top  16   c  and bottom  16   d  except for a bottom opening  17  intermediate the ends.  
         [0027]     In an exemplary embodiment illustrated in  FIG. 3  the blade carrier  14  has a proximal portion  14   a,  a distal portion  14   b,  and a lower edge  14   c  having three representative notches  3 ,  2 , and  6 , the functions of which will be described below. A pair of longitudinally spaced blade guide pins  1  are located on the distal portion of blade carrier  14 , and project laterally. Handle pin  8  projects from the forward portion of mounting pocket or recess  9 , which is located on the proximal portion of blade carrier  14 . Blade carrier  14  is further provided with a guide channel  18  which is configured to interfit with a guide track of sleeve  16 . The guide channel  18  allows the sleeve  16  to slide along the blade carrier  14  in a controlled and smooth manner.  
         [0028]     The distal portion of blade carrier  14  is fastened to the blade  12  by inserting guide pins  1  into an opening  11  on the blade  12 , which are then riveted to securely attach the blade  12  to the blade carrier  14  to form the elongated blade assembly  33  (an example of which is seen in  FIG. 14B ). Blade  12  may be fastened to blade carrier  14  using thermal or ultrasound riveting methods. The attached blade is thus offset relative to the blade carrier centerline.  
         [0029]      FIG. 13  illustrates another embodiment of the blade carrier which has a guide pin  1  longitudinally spaced from a second guide pin  1   a  that projects laterally. For example, guide pin  1   a  may be configured as a laterally projecting hook. It is an aspect of this embodiment that in fastening the blade to the blade carrier, only guide pin  1  is riveted during the fastening process.  
         [0030]      FIGS. 2, 8 , and  10  illustrate various embodiments of the sleeve  16 .  FIG. 2  shows an embodiment of sleeve  16  having a cantilevered retention tooth  13  with an associated release button  10 . Preferably, the cantilevered retention tooth  13  and release button  10  is connected to sleeve  16  by two leg portions  15  integral with the body of the sleeve and extending downwardly and obliquely forward alongside the opening  17  to form an integral shank. Legs  15  are configured to urge the retention tooth  13  into resilient contact with the bottom edge  14   c  of the blade carrier  14 , strongly enough for the tooth  13  to enter and exert pressure against any of the notches that are encountered as the sleeve  16  slides relative to the blade assembly. The release button or tab  10  is also integrally formed on the legs  15 , below the tooth and the bottom surface of the sleeve. The geometric relationship between the release button  10  and legs  15  are such that a forward pressing of the button  10  bends the legs  15  forward and thus pulls the tooth  13  downwardly, away from the bottom edge  14   c  of the blade carrier. It is an aspect of this embodiment that the tooth  13  and the button  10  are at all times below or within the opening  17  in the bottom of the sleeve. It is also preferred that sleeve  16  have an interior with a channel  38  and rail  36  configuration (an example of which is seen in  FIG. 10 ).  
         [0031]      FIG. 10  illustrates another embodiment of the sleeve  16  having two legs  15 ′, a cantilevered tooth  13 ′, and an associated release button  10 ′ positioned at the opening at the proximal end  16   a . As seen in  FIG. 10 , according to this embodiment there is no opening  17  along the bottom  16   d  of the sleeve. Retention tooth  13 ′ and release button  10 ′ function and are manipulated in a manner analogous to the embodiment of  FIG. 2 .  FIG. 10  also illustrates the channel  38  and rail  36  which together form a guide track  19  that is complementary to the guide channels  18  on the blade carrier  14 . Guide track  19  is also illustrated in  FIGS. 11   a  and  11   b . The channel and rail configuration of guide track  19  allows for sleeve  16  to be moved relative to the blade carrier  14  in a controlled and stable manner.  
         [0032]     The pre-assembly cartridge  22  is complete after the distal end of sleeve  16  is pushed over the proximal portion of blade carrier  14  until the retention tooth  13  of the sleeve  16  engages with the notch  2  of the blade carrier  14  as seen in  FIGS. 2 and 3 . Thereafter, the pre-assembly cartridge  22  is sterilized and stored in a sealed container.  
         [0033]     As illustrated in  FIG. 4 , handle  24  has proximal and distal portions  24   a,    24   b,  the latter having a mounting end  25  configured with an off-center mounting tongue  7  and a locating bore  26  suitable to engage the handle pin  8  located on the proximal portion of blade carrier  14 .  
         [0034]     Assembly of the surgical instrument is completed by attaching the distal portion of handle  24  to the pre-assembly cartridge  22  by inserting the handle pin  8  of the blade carrier  14  into the locating bore  26  of the handle  24 . As illustrated in  FIG. 4 , the distal portion of handle  24  and proximal portion of blade carrier  14  are laterally pushed together until the mounting tongue  7  completely engages the mounting pocket  9  of the blade carrier  14 . The handle and the blade are thus offset on the same side of the blade carrier. The proximal end of sleeve  16  is then pulled toward the handle  24 , until the retention tooth  13  engages with the notch  3  of the blade carrier  14 . This configuration is the assembled condition and, as shown in  FIG. 6 , the blade  12  remains protected by virtue of its location within the sleeve  16 . In the assembled condition, the blade carrier  14  is firmly retained on the handle  24  by the overlap of the proximal portion  16   a  with the distal end  24   b  of the handle which includes mounting tongue  7 , pin  8 , and bore  26 .  
         [0035]     Handle  24  also has a notch  4  on lower edge  24   c  for engaging the retention tooth  13  of sleeve  16  during periods when the instrument is in use. Specifically, when the retention tooth  13  is engaged with notch  4  the blade  12  is exposed for cutting. This cutting condition is best seen in  FIG. 6 . The blade  12  is exposed by sliding the proximal end of sleeve  16  in a longitudinal direction toward the handle  24  until the retention tooth  13  engages with notch  4  on the handle  24 . As depicted in  FIG. 6 , in the cutting condition the distal end  16   b  of the sleeve  16  is positioned behind the blade  12  thus exposing the blade  12  for use. In a preferred embodiment the sloped portion  5  of lower edge  24   c  of the handle  24  forward of notch  4  facilitates the engagement of retention tooth  13  and notch  4 .  
         [0036]     During use of the instrument, it is often desirable to temporarily cover and/or withdraw the blade  12 . This can be accomplished by depressing the button  10  located adjacent to the retention tooth  13 . This action unlocks the sleeve  16  and allows it to slide forward to the point where retention tooth  13  rests in notch  3  of the blade carrier  14 . This is the protected condition and in this condition, the blade  12  is temporarily protected by the distal portion of sleeve  14 . This temporary protection feature allows for safer person-to-person transfer of the scalpel during a surgical procedure. Moreover, the blade can be repeatedly covered and uncovered as necessary.  
         [0037]     At the conclusion of a surgical procedure, the cartridge  22  can be safely and quickly removed while retaining the handle  24 . This is achieved by depressing the button  10  and pushing the distal portion of sleeve  16  longitudinally away from handle  24  until an audible click is heard. As shown in  FIG. 7 , retention tooth  13  of sleeve  16  engages notch  6  on the blade carrier  14  and effectively locks the sleeve  16  in this position. Once the sleeve  16  is in the locked condition it is very difficult to return to the other conditions.  
         [0038]     Having sleeve  16  in the locked condition prevents re-exposure of the blade  12 , which in turn makes accidental reuse of a contaminated blade virtually impossible. In another embodiment, pushing the distal portion of sleeve  16  so as to engage retention tooth  13  with notch  6  exposes a suitable “previous use” marking M (also seen in  FIG. 7 ) which provides an additional measure of safety. Exposing a “previous use” marking in this manner would allow would-be users to quickly ascertain by visual inspection that a particular surgical instrument should not be used. Once the sleeve  16  is locked, cartridge  22  is then completely disengaged laterally from the handle and disposed of.  
         [0039]     It is noteworthy that once the scalpel has been assembled, the sliding of the sleeve between the protected condition and the use condition can be accomplished by manipulation with the fingers of the same hand as is holding the blade. Likewise, at the conclusion of the surgical procedure, the sleeve can be pushed to the disposal position with only the fingers of the hand that holds the handle. This procedure avoids any possibility that the other hand might come into contact with the exposed blade.  
         [0040]     If the sleeve  16  and the blade carrier  14  are manufactured from the same transparent material, the type and size of the blade  12  would be indicated by an appropriate marking located on the blade carrier  14  and would be visible through the sleeve  16 . This embodiment would simplify recycling and/or disposal of both the blade  12  and the sleeve  16 , as no separation by color or material would be required. In another aspect, the blade  12  could be re-sharpened and re-sterilized and the sleeve  16  and carrier  14  could be reused/recycled.  
         [0041]      FIGS. 8 and 9  illustrate a second embodiment of the pre-assembly cartridge  22 ′ and its use in a completed scalpel. According to this embodiment sleeve  16 ′ has a retention tooth  13 ′ that is pivotally supported by the sleeve  16 ′ below the opening  17 ′ on the underside of the sleeve. It is a further aspect of this embodiment that the notch  3 ′ on the blade carrier  12 ′ is modified, but functions according to the same sequence as previously described with respect to the embodiment of  FIG. 1 .  
         [0042]     The embodiments shown in  FIGS. 8 and 9  address the risk posed when a scalpel having a heavy stainless steel handle is dropped or falls onto the floor or other hard surface. When a scalpel strikes such a surface the impact might cause the blade to be accidentally exposed. Thus, it is an aspect of the second embodiment of retention tooth  13 ′ and notch  3 ′ as illustrated in  FIGS. 8 and 9  to provide a more robust connection and substantially reduce the risk of accidental exposure.  
         [0043]     According to this embodiment, the sleeve  16 ′ is moved along the blade carrier  14 ′ and handle  24 ′ by depressing the button  10 ′. This tooth and button configuration  10 ′,  13 ′ is somewhat different than the previously described configuration, in that the legs  15 ′ are more rigid, and the movement of the tooth  13  is pivotal about the axis of the button  10 , rather than from bending of the legs  15 . As shown in  FIG. 9 , when the retention tooth  13 ′ is engaged with the notch  3 ′, the steep angle of the notch  3 ′ prevents accidental blade exposure in the event the instrument is dropped. With this alternative configuration, the blade carrier  14 ′ remains attached to the handle  24 ′ with the blade  12 ′ still protected. In order to move the sleeve  16 ′ to expose the blade  12 ′ the button  10 ′ adjacent to the retention tooth  13 ′ must be depressed.  
         [0044]     In the embodiment of  FIG. 12 , the opening  17 ′ is formed in the lower distal portion of the sleeve, leaving a hood or similar overhang at the upper distal portion of the sleeve, for covering the mounting formation at the proximal portion of the handle. This embodiment of the sleeve is easier to manufacture.  
         [0045]      FIGS. 14A-14E  illustrate the preferred method for assembling the safety scalpel as exemplified by the embodiments of  FIGS. 8, 9  and  12 . According to this aspect of the invention, numerous sleeves  16  are placed on an assembly rod  32 . The assembly rod  32  preferably has means, such as a protrusion on the bottom, for preventing the sleeves from slipping off the assembly rod. The protrusion  30  temporarily catches the retention tooth  13  of the lead sleeve. It is also preferred that the leading end of the assembly rod  32  is shaped like the mounting end  25  of handle  24  and that the top edge of the assembly rod have a guide channel  18 ′ that is complementary to the guide track  19  of the blade carrier  14 . The assembly rod  32  has a mounting tongue  7 ′ and a locating bore  26 ′ to engage the proximal end of one of a series of blade carriers  14  that have been pre-assembled with respective blades  12 . Together, the blade carrier  14  and blade  12  form an elongated blade assembly  33  that is temporarily attached to the assembly rod  32 . Once the elongated blade assembly  33  is attached, the sleeve  16  can be moved to its final position over the blade  12 . In its final position, retention tooth  13  is resting in notch  2  of the blade carrier  14 . The completed pre-assembly cartridge  22  is then removed from the assembly rod  32  and is ready for sterilization and packaging. The next sleeve is then ready for attachment to the next of the ready supply of blade assemblies  33 .