Patent Publication Number: US-2013245655-A1

Title: Concealed blade scalpel

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application Ser. No. 61/608,725 filed Mar. 9, 2012, which is hereby incorporated by reference herein in its entirety 
    
    
     FIELD OF THE INVENTION 
     This invention generally relates to scalpels and lancets, which are small and extremely sharp-bladed instruments used in the medical field for performing surgical procedures on patients and for anatomical dissection. These instruments are extensively used in procedures performed in operating rooms as well as in clinical settings. They are also used in arts, crafts, box cutting and various everyday applications. They are intended for cutting, incising, stabbing or enucleating body tissues, depending on the shape of the sharp edge of the blade. Scalpels are typically single-piece structures consisting of a sharp blade, usually made of hardened and tempered stainless steel or high carbon steel, reversibly or permanently attached to a rigid elongated handle that permits manipulation by the user to perform the desired procedures. Blades with permanently attached handles are usually disposable, while handles with removably attached blades are typically re-usable with fresh blades. Disposable scalpels usually have a plastic handle with a blade, and the entire instrument is discarded after a single use. Re-usable scalpels can have attached re-sharpenable blades or, more commonly, removable and replaceable blades. Double-edged scalpels are referred to as “lancets.” 
     A disposable scalpel having a retractable blade is disclosed in Haining U.S. Pat. No. 5,330,493. That scalpel has a blade with a bifurcated body installed inside the handle; the blade is detachable and replaceable and held in position by diverging legs. The blade can be positioned in exposed, intermediate, retracted and locked position. 
     Another scalpel with a spring-loaded, automatically retracted blade is disclosed in Platts U.S. Pat. No. 5,403,337. The Platts scalpel has a detachable and retractable blade. The scalpel has two channels, one for a spring that runs along the entire length and another for the blade. Both the spring and the blade are detachable and removable. The blade is accessible through side windows, and there are tabs that permit the localization of the blade wherever it is necessary. It has two tabs  20  near the front end and another tab  22  near the rear end, both on the same surface. A spring  26  extends from the front end and pushes the blade backwards by engaging a step on the blade. The spring, which constantly biases the blade inside the handle, is a compression spring that must be further compressed or shortened to advance the blade. Latches maintain the spring at different locations. 
     Another retractable knife is disclosed in Knoop U.S. Pat. No. 4,805,304 which shows an oval knife split in the middle into two halves. Each half has a central semi-circular channel carved out to form space to lodge the blade; the channel is open at the front end, for exposing the blade for cutting, while the other end of the channel is blind. Near the front end, the sides of the knife body have two oval windows on each side to expose both sides of the blade, and two concave switches are fastened to the sides of the blade. When advanced, the two concave switches are expected to advance the sharp end of the blade through the front end of the knife. The Knoop cites Anderson U.S. Pat. No. 2,862,296 as teaching a similar enclosure of a blade in the center of two halves of a knife. The blade is expected to be advanced through a window on the side for accessing a switch attached to the blade and another window on the back side. Knoop teaches that windows to advance the blade and to access the switch must be present on both sides and both halves of the blade. When an extension spring is used and relied on to advance a blade by stretching, its anchored end and anchor must be established; otherwise an effort to advance the blade can cause the entire knife to slip out and fall off the handle. Special features to move the knife backwards, while the blade is advanced forward, must be provided. It is also essential that these two counter-acting forces be applied at the same location. 
     Other examples of safety scalpels are disclosed in U.S. Pat. Nos. 7,900,362, 7,857,824, 7,669,337, 7,153,317, 6,979,340, 6,757,977, 6,629,985, 6,589,258, 6,022,364, 5,868,771, 5,779,724, 5,571,127, 5,569,282, 5,423,843, 5,417,704, 5,342,379, 5,330,492 and 5,292,329. 
     SUMMARY 
     According to one embodiment, a concealed-blade scalpel includes an elongated housing forming an interior cavity and an opening at one end of the housing to provide access to the interior cavity. A surgical cutting blade is mounted within the cavity for sliding movement relative to the housing so that the blade can be moved between (1) a retracted position in which the cutting edge of the blade is located entirely within the cavity, and (2) an advanced position in which the cutting edge of the blade is positioned outside the housing to permit the blade to be used for cutting. A biasing element is mounted within the cavity and coupled to the blade and the housing for urging the blade toward the retracted position. An actuator is coupled to the blade for manually moving the blade to the advanced position in response to manual pressure applied to the actuator, and the biasing element continuously urges the blade toward the retracted position so that the blade is automatically moved to the retracted position when the manual pressure applied to the actuator is removed or reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood from the following description of preferred embodiments together with reference to the accompanying drawings, in which: 
         FIG. 1  is a front perspective view of a surgical scalpel with its blade in a fully advanced position. 
         FIG. 2  is an exploded front perspective view of the scalpel shown in  FIG. 1 , with the hinged portion of its housing open. 
         FIG. 3  is an exploded front perspective of the scalpel shown in  FIG. 1 , from the opposite side of the scalpel, with the hinged portion of its housing open. 
         FIG. 4A  is an enlarged side elevation of the distal portion of the housing of the scalpel of  FIG. 1 , with the hinged portion of the housing open. 
         FIG. 4B  is a top plan view of the scalpel of  FIG. 1 . 
         FIG. 5  is an enlarged section taken along line  5 - 5  in  FIG.4B . 
         FIG. 6  is an enlarged section taken along line  6 - 6  in  FIG. 4B . 
         FIG. 7  is a further enlarged section taken along line  7 - 7  in  FIG. 4B . 
         FIG. 8  is an enlarged section taken along line  8 - 8  in  FIG. 4B . 
         FIG. 9  is an enlarged section taken along line  9 - 9  in  FIG. 4B . 
         FIG. 10  is an enlarged section taken along line  10 - 10  in  FIG. 4B . 
         FIG. 11  is a front perspective view of a modified surgical scalpel with its blade fully retracted. 
         FIG. 12  is an exploded front perspective view of the scalpel shown in  FIG. 11 , with the hinged portion of its housing open. 
         FIG. 13  is an exploded front perspective of the scalpel shown in  FIG. 11 , from the opposite side of the scalpel, with the hinged portion of its housing open. 
         FIG. 14  is a top plan view of a left-hand end portion the scalpel of  FIG. 11 . 
         FIG. 15  is an end elevation of the scalpel of  FIG. 11 , taken from the left-hand end as viewed in  FIG. 11 . 
         FIG. 16  is a side elevation of the portion of the scalpel shown in  FIG. 14 . 
         FIG. 17  is an enlarged section taken along the line  17 - 17  in  FIG. 15 , with the actuator in its retracted position. 
         FIG. 18  is the same sectional view shown in  FIG. 17 , with the actuator moved to a partially advanced position. 
         FIG. 19  is the same sectional view shown in  FIG. 17 , with the actuator moved to its fully advanced position. 
         FIG. 20  is an exploded front perspective from one side of another modified surgical scalpel. 
         FIG. 21  is an exploded perspective from the opposite side of the scalpel shown in  FIG. 20 . 
         FIG. 22  is an enlarged longitudinal section taken through the middle of a portion of the scalpel of  FIGS. 20 and 21 . 
         FIG. 23  is a longitudinal section taken through the same portion of the scalpel shown in  FIG. 22  but laterally offset from the section shown in  FIG. 22 . 
         FIG. 24  is the same exploded perspective shown in  FIG. 21  but with a different serpentine element. 
         FIG. 25  is an enlarged longitudinal section taken along one side of the serpentine element in the scalpel shown in  FIG. 24 . 
         FIG. 26  is a further enlarged longitudinal section, orthogonal to the section shown in  FIG. 25 , taken through the center of one end portion of the serpentine element in the scalpel shown in  FIG. 24 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Although the invention will be described in connection with certain preferred embodiments, it will be understood that the invention is not limited to those particular embodiments. On the contrary, the invention is intended to cover all alternatives, modifications, and equivalent arrangements as may be included within the spirit and scope of the invention as defined by the appended claims. 
     Turning now to the drawings,  FIGS. 1-5  illustrate a scalpel having a molded plastic housing  10  with a rigid proximal portion  11  and a distal portion  12  that contains a surgical cutting blade  20 . The distal portion  12  of the housing  10  is divided into first and second halves  12   a  and  12   b,  joined by a living hinge  13  so that the first half  12   a  can be pivoted relative to the second half  12   b  for opening and closing an internal cavity  14  (see  FIGS. 7-9 ). The cavity  14  is formed by recesses in the opposed surfaces of the two sections  12   a  and  12   b  when the two halves  12   a  and  12   b  are in their closed positions depicted in  FIGS. 1 ,  4 B and  6 - 10 . 
     When the two halves  12   a  and  12   b  are folded against each other, multiple pins  15  spaced along the free long edge of the first half  12   a  fit into mating holes  16  spaced along the free longitudinal edge of the second half  12   b.  The pins  15  can be locked in the holes  16  by a variety of different techniques, such as mechanical locking via detents formed by the surfaces of the pins and the side walls of the holes, heat staking the pins  15  to the second half  12   a  of the housing, adhesive bonding, etc. It is preferable that the locking of the two halves of the housing be irreversible, to prevent access to the sharp blade  20  when it is retracted inside the housing  10 , as described in detail below. 
     To facilitate gripping the scalpel anywhere along the distal portion  12  of the housing, a series of angled projections  17  are formed along both the top and bottom edges of both sides of the distal portion  12  of the housing. 
     Within the cavity  14 , the blade  20  is fastened to a carrier  21  configured for longitudinal sliding movement in the cavity  14 . The main body of the blade  20  forms an elongated slot  22  that fits over a pair of ribs  23  and  24 , and between a second pair of ribs  25  and  26 , on one side of the carrier  21 . The outer surfaces of the four ribs  23 - 26  are thermally deformed to slightly overlap the surface of the blade  20 , to stake the blade to one side of the carrier  21 . Thus, the blade  20  is integrally joined with the carrier  21  so that the blade  20  moves along with the carrier  21  during sliding movement of the carrier  21  within the cavity  14 . The cutting edge  20   a  of the blade  20  projects distally beyond the distal end of the carrier  21  so that when the carrier is advanced to its most distal position, the cutting edge of the blade  20  projects beyond the distal end of the housing  10  so that the blade can be used for cutting. Conversely, when the carrier  21  is retracted to its most proximal position, the blade  20  is retracted entirely within the cavity  14  so that the blade cannot cause any accidental cuts during handling. 
     To permit guided sliding movement of the carrier  21 , a pair of guide pins  30  and  31  (see  FIGS. 2 ,  3  and  5 ) project laterally form one side of the carrier and ride in a corresponding pair of guide channels  33  and  34 , respectively, in the cavity wall formed by the housing section  12   b.  The ends of the channels  33  and  34  determine the locations of the fully retracted and fully advanced positions of the carrier  21 , i.e., the carrier locations where the ends of the channels  33  and  34  are engaged by the respective pins  30  and  31  of the carrier  21 . The guide channel  33  has a notch  33   a  at the distal end of the channel so that the user feels a “click” when the carrier  21  reaches its most advanced position. 
     The carrier  21  is continuously urged toward its retracted position by a continuous retracting biasing force exerted on the carrier by a coil spring  36 , so the carrier  21  can be advanced only by the application of an external manual force that overcomes the biasing force of the spring  36 . As soon as that manual force is reduced below that of the spring  36 , the carrier  21  is quickly and automatically retracted by the biasing force exerted on the carrier  21  by the spring. The spring  36  is located within the cavity  14  with the proximal end of the spring  36  attached to the proximal section  11  of the housing  10 , and the distal end of the spring  36  attached to the carrier  21 . Specifically, closed loops  36   a  and  36   b  on the proximal and distal ends, respectively, of the spring  36  are looped over respective hooks  37  and  38  on the housing section  12   a  and the carrier  21 . 
     The spring  36  is contained in a cylindrical cavity formed by a pair of matching semi-cylindrical recesses  39   a  and  39   b  formed in the hinged housing sections  12   a  and  12   b,  respectively. The spring  36  is always partially extended when attached to the two hooks  37  and  38 , so that the spring continuously biases the carrier  21  toward its retracted position, regardless of the position of the carrier along its permitted range of longitudinal movement. Even when the carrier  21  is in its fully retracted position the spring  36  biases the carrier  21  toward its retracted position, by urging the carrier pins  30  and  31  against the proximal ends of the guide slots  33  and  34 . 
     Advancing movement of the carrier  21 , toward the distal end of the housing  10 , is effected by manually applying pressure to a sliding actuator  40  attached to one side of the carrier by three pins  41 - 43  formed by the actuator  40  and extending through a slot  44  in the housing section  12   a.  The three pins  41 - 43  fit snugly into mating holes  45 - 47  in the carrier  21 , and can be thermally staked to the carrier. The pins  41 - 43  are formed on the ends of a pair of guide lugs  41   a  and  42   a  that ride within the slot  44 . The proximal portion of the slot  44  is narrower than the distal portion, is only slightly wider than the width of the guide lug  42   a,  and extends along the full length of travel of the lug  42   a.  The lug  42   a  abuts the proximal end of the slot  44  at the same retracted limit position at which the carrier pins  30  and  31  abut the proximal ends of their respective channels  33  and  34 . The guide lug  41   a  is spaced distally from the lug  42   a  and abuts the distal end of the slot  44  at the same advanced limit position at which the carrier pins  30  and  31  abut the distal ends of their respective channels  33  and  34 . 
     A pair of guide pins  48  and  49  formed by the carrier  21  also extend into the slot  44 , and a third guide pin  50  rides in a channel  51  formed in the interior surface of the housing section  12   a.  The pin  50  is directly opposite the pin  30  on the carrier, and the channel  51  includes a notch  51   a  at the same longitudinal location as the notch  33   a  in the channel  33 . The pin  50  abuts the proximal end of the channel  51  at the same retracted limit position at which the carrier pins  30  and  31  abut the proximal ends of their respective channels  33  and  34 . 
     The actuator  40  slides on the exterior surface of the housing section  12   a,  guided by the walls of the slot  44  and the channels  33 - 35  and  51 , with the proximal ends of the channels  34 ,  35  and  51  defining the limit for retracting movement of the actuator  40 , and the distal ends of the channels  33  and  34  defining the limit for advancing movement of the actuator  40 . A pair of beads  52  and  53  formed on the bottom of the actuator  40  ride on a rail  54  formed on the exterior surface of the housing section  21   a  along one edge of the slot  44 . 
     The top of the sliding actuator  40  has a serrated surface  55  to facilitate gripping the scalpel, and the distal end of the serrated surface  55  has a raised lip  56  to facilitate pushing the actuator distally toward its most advanced position, against the retracting force exerted on the carrier  21  by the biasing spring  36 . A similar stationary gripping surface  60  is molded into the distal end portion of the housing section  12   b,  with a raised lip  61  positioned at the proximal end of the gripping surface  60  rather than the distal end. When the user slides the movable actuator  40  forwardly, e.g., by pressing his or her thumb against the lip  56 , the stationary gripping surface  60  on the opposite side of the scalpel can be pressed in the opposite (retracting) direction by pressing a finger against the lip  61 . This permits the user to precisely control the scalpel during a cutting operation, while maintaining the pressure required to keep the blade in its advanced position. 
     When the advancing pressure applied to the actuator  40  is removed or reduced below the level of the retracting force applied by the spring  30 , the retracting force applied to the carrier  21  by the spring  36  pulls the carrier  21  to its retracted position and then holds the carrier in that position. Thus, if a user of the scalpel pushes the sliding actuator  40  forward to move the blade  20  to its most advanced position, for use in a cutting operation, and then releases the actuator  40  when the cutting operation is completed, the spring  36  immediately pulls the carrier  21  and thus the blade  20  to their fully retracted positions, concealing the blade  20  entirely within the housing  10 . This is a safety feature that permits the blade  20  to be in its advanced position only as long as advancing pressure is applied to the actuator  40 , and automatically retracting the blade as soon as that pressure is released, without any further action by the user. 
     The sliding actuator  40  is a particularly appropriate actuator for use in surgical procedures in which the surgeon grips the scalpel with a “palm” grip. Other embodiments, to be described below, are more appropriate for other types of grips, such as the “fingertip” grip and the “pencil” grip. For example, the embodiment illustrated in  FIGS. 11-19  utilizes a pivoting actuator  100  that can be conveniently manipulated with the surgeon&#39;s index finger when a “fingertip” grip is used. Except for the actuator and the two hinged housing sections, the structure and operation of this embodiment is the same as that described above in connection with  FIGS. 1-10 . The hinged housing sections  101  and  102  in the embodiment of  FIGS. 11-19  include arched extensions  101   a  and  102   a  that protrude upwardly to form a cavity with an aperture  103  on one side for receiving the pivoting actuator  100 . The actuator  100  includes a cylindrical portion  104  that extends through the aperture  103  and forms a recess  105  that fits over a pin  106  to permit pivoting movement of the actuator  100  about the axis of the pin  106 . 
     To connect the actuator  100  to the carrier  21  that carries the scalpel blade  20 , a link  107  extending downwardly from the cylindrical portion  104  forms a slot  108  that fits over the pin  48  on the carrier  21 . The actuator  100  is biased to its uppermost position ( FIGS. 16 and 17 ) by a spring  109 . When the actuator  100  is manually pivoted downwardly around the axis of the pin  106 , in a clockwise direction as viewed in  FIGS. 17-19 , the walls of the slot  108  cam the carrier  21  longitudinally to advance the carrier  21  and the blade  20  to their advanced positions where the blade  20  is exposed for use in a cutting procedure. When manual pressure is removed from the actuator  100 , the spring  109  returns the actuator  100  to its uppermost position, and the retracting spring  36  retracts the carrier  21 , and thus the blade  20 , in the same manner described above in connection with  FIGS. 1-10 . 
     Another embodiment, illustrated in  FIGS. 20-26 , replaces the actuators  40  and  100  with a housing section  200  made of a flexible and resilient material so that it can be deformed inwardly against the crests  203   a  and  203   b  of a serpentine element  201 , which is also made of a flexible and resilient material. The serpentine element  201  has opposite end tabs  201  a and  201   b  with respective apertures  202   a  and  202   b  for attachment to a blade carrier  202  and to a housing  210 , respectively. Specifically, the aperture  202   a  fits over a post  37  on the housing  210 , and the aperture  202   b  fits over a post  208  on a blade carrier  202 . Thus, when the serpentine element  201  is extended by pressing down on the crests  203   a  and  203   b  of the serpentine element  201 , the blade carrier  202  is moved relative to the housing section  210 , thereby advancing the blade  20  out of the housing  210 . 
     To advance the blade carrier  202 , the user simply squeezes the flexible housing section  200  inwardly against the crests  203   a  and  203   b  of the serpentine element  201 . This reduces the height of the crests, which in turn elongates the serpentine element  201  to push the carrier  202  forwardly relative to the housing section  210 , thereby advancing the blade  20  to its exposed position outside the housing. The blade  20  will remain in this advanced position as long as sufficient pressure is maintained on the resilient housing section  200  to maintain the serpentine element  201  in its elongated condition. When that pressure is released, the resilient serpentine element  201  returns to its original shape, which tends to pull the carrier  202  back to its retracted position. The biasing spring  36  ensures that the carrier  202  is quickly retracted, by augmenting the retracting force applied to the carrier by the serpentine element  201 . 
     In order to maintain the central valley portion  203   c  of the serpentine element  201  (between the two crests  203   a  and  203   b ) in the same plane as the two end tabs  201   a  and  201   b,  a pair of bosses  204  project laterally from opposite sides of the center of the valley portion  203   c.  These bosses  204  fit into a pair of channels  212  formed in the ribs of the carrier  202 . This permits the bosses to move longitudinally within the channels  212  while maintaining the valley portion  203   c  at a fixed elevation, so that the elongation of the serpentine element  201  is dependent entirely on the degree of deformation of the two crests  203   a  and  203   b.    
     In a further modified embodiment illustrated in  FIGS. 24-26 , the serpentine element is in the form of a multi-coil spring  215  that is both flexible and resilient. The spring  215  is formed by a single wire that forms multiple coils  216   a - 216   h  interconnected by linear wire segments  217  to form a general serpentine shape. Bent end portions  218   a  and  218   b  are formed on opposite ends of the spring  215  to attach the spring  215  to the housing  210  at one end and to the carrier  202  at the other end. When the flexible housing section  200  is deformed inwardly against the crests formed by alternate ones of the coils  216   a - 216   h  (see  FIG. 25 ), the overall length of the multi-coil spring  215  increases, which causes the spring  215  to push the blade carrier  202  forwardly, thereby advancing the blade  20  to its exposed position outside the housing. The blade  20  will remain in this advanced position as long as sufficient pressure is maintained on the resilient housing section  200 . When that pressure is released, the spring  215  returns to its original shape, which tends to pull the carrier  202  back to its retracted position. The biasing spring  36  ensures that the carrier  202  is quickly retracted, by augmenting the retracting force applied to the carrier by the spring  215 . 
     While particular embodiments and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations may be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims.