Abstract:
A surgical safety scalpel comprising a blade, fixed at one end to an extended nose on a handle, covered with a sheath longitudinally slidably and inseparably mounted on said handle, said sheath comprising an elongated housing comprising an upper surface, a lower surface and two side surfaces connecting the upper and lower surfaces together, an aperture through said lower surface and a handle with a first button mounted on surface of said handle and aligned opposite to the said first button a second button wherein the said aperture on the sheath engages with the first button and second button in the blocking position of covering the said blade and wherein a base of the said sheath engages with a third button near the proximal end of tail of the said handle preventing the said sheath to slide of the handle when the sheath is in ready position and wherein the said second button also engages the said sheath from sliding over the said blade its exposed state and during use.

Description:
FIELD OF INVENTION 
       [0001]    This invention relates generally to surgical scalpels and, more particularly, to surgical scalpels having shields or guards to cover the scalpel blade when not in use. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the world prevalent with AIDS epidemic and Hepatitis B and C epidemics, accidental needle sticks and scalpel cuts have become a major concern to health-care worker. According to a study, the conversion rate for HIV positive needle sticks is 1 in 250 sticks. The conversion rate for scalpel cuts is unknown but according to a study of 10,000 health care workers, it is believed that the conversion rate is higher (as per U.S. Pat. No. 5,342,379). It is well known and understood by healthcare workers that sharp surgical instruments, such as scalpels, have a significant potential for harm to healthcare workers. The rapid handling of these sharp instruments can lead to accidental cuts or puncture wounds during surgery. 
         [0003]    Thus, there is an inherent incentive for improvement in the improving scalpel technology that can reduce and more ideally eradicate scalpel cuts to the heal care worker. The chances of the healthcare worker contracting some fatal infection or disease because of accidental scalpel cut comes with a heavily price on the society and their healthcare The scalpel has not had many basic changes made in the past 100 years other than disposable blades and micro-surgical sizes. 
         [0004]    Typically, maximum scalpel cuts or stabs occur in specific situations, such as a surgery. Another occasion is at the time of passing a used scalpel to a scrub nurse. Another is when a surgeon swabs a bleeder and accidentally stabs himself (when he forgets that the scalpel is in his other hand). Trauma cases are another high risk situation in which an accidental laceration can occur because there many people simultaneously working on these cases and people are rushing to perform their tasks. Yet another case of accidental stabs is that the blade shield is lost or misplaced, the scalpel becomes dangerous for practically anyone and everyone in the proximity of the exposed scalpel blade. Another instance is during the disposal of medical waste, stabbing may occur because of accidental removal of the blade shield. 
         [0005]    During the course of a surgery, the healthcare worker will usually remove the shield and give the exposed scalpel blade to the doctor. Similarly after completion of the use of the scalpel, the surgeon may hand the exposed scalpel blade to the healthcare worker for covering. This process results in loss of time and may cause accidental stabbing of the healthcare worker or the surgeon. During waste disposal, the disposer is not usually careful in handling the waste and may handle the waste roughly, which may result in removal of the shield (if already not attached) and cause stabbing. This could also lead to spread of infection in the general public. Thus, there is a need to protect the healthcare workers from accidental scalpel stabs 
         [0006]    To address this issue, the in the recent years, scalpels with disposable blade portions have been made. In this type of scalpel, the blade component is detachable from the handle component and disposed of by deposit in a special container. It will be appreciated, however, that such disposable of blades still present a hazard to the individual who must detach and transfer the blade component. 
         [0007]    Similarly, blade shields have been developed to cover the scalpel blade when the scalpel is not in use. While early blade shields did help reduce the potential for accidental cuts or puncture wounds, there were some problem areas. For example, safety scalpels are known that have a retractable external sheath but they require two hands to operate. Some of the blade shields are awkward to operate. Others included complex mechanical mechanisms to move the shield, which mechanisms could be prone to mechanical failure. 
         [0008]    Attempts have been made to cover the blade in the knives itself by providing a hollow handle component with a slidable blade therein. Basically, these instruments employ the handle component as a sheath for the blade component when not in use. Typically, such sheathable blade assemblies are not contemplated for disposal after a single use. Furthermore, such cutting instruments do not provide a positive means for preventing the unsheathing of the blade portion by a careless handler when disposal of the blade is desired. 
         [0009]    Therefore, it is an object of the invention to provide a surgical scalpel assembly that reduces the complexity of prior known scalpel devices and which also provides additional safety and manufacturing benefits over known scalpel systems. 
       SUMMARY OF THE INVENTION 
       [0010]    A surgical safety scalpel comprising a scalpel handle with a provision to removably attach a disposal scalpel blade at one end and a longitudinally moveable blade sheath on the handle. The sheath is securely attached to the scalpel handle and entirely covers the scalpel blade in closed and protective state or blocking position. The shield can be made to slide down towards the tail of the scalpel handle and lock on the central part of the scalpel handle when the scalpel blade is in its exposed state. The sheath is a hollow body that locks on the scalpel handle by windows provided on the lower part of the sheath which windows interlock with the stoppers/buttons at the proximal end of the scalpel blade attachment near the stem of scalpel blade. The first button/stopper prevents the sheath to be dislodged when in blocking position. During this blocking position the second stopper prevents the sheath from sliding down over the handle by radially exerting force on to a lowest part of the sheath. The second stopper is placed inside a groove/recess on the handle and projects outwards. The second button has elastic nature and exerts outwards force. When the sheath is in blocking position the outward exerted force keeps the sheath in such blocking position. When the sheath is ready position the tail stopper prevents the sheath from sliding off the handle. The window may have a small projection inside the window extending parallel or substantially parallel to the handle, which projection interlocks with the first stopper in the blocking position. The sheath has a drip on the sheath surface to assist in transition the sheath from ready position to blocking position over the blade and provide traction for the user. 
         [0011]    The scalpel blade can be simply covered with the sheath by using one hand and more particularly one digit of the hand holding the scalpel to actuate release mechanism. The scalpel blade is covered by the shield with a shift of the thumb. This covering can be affected after each cut has been made. The sheathing is a smooth single hand operation without any risk of cutting oneself. 
         [0012]    An object and advantage of the invention is to provide a safety sheath for the scalpel blade wherein the sheath forms an integral and inseparable part of the body of the scalpel. 
         [0013]    Another object and advantage of this invention is that the sheath does not require to be removed from the scalpel blade during surgery. 
         [0014]    Yet another object and advantage of this invention is the locking of the sheath on the body of the scalpel so that the sheath cannot be removed from the scalpel body easily or accidentally. Deliberate attempt and a lot of force will be required to remove the shield from the body of the scalpel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a view of the embodiment of the blade and sheath of the instant invention together with a scalpel handle. 
           [0016]      FIG. 2  is a perspective view of the blade and sheath of the present invention in the blocking position. 
           [0017]      FIG. 3  is a cross-sectional view of the blade and sheath of the present invention in blocking position. 
           [0018]      FIG. 4  is an exploded cross-sectional view of the interlocking mechanism when the sheath is in the blocking position. 
           [0019]      FIG. 5  is a perspective view of the blade and sheath of the present invention together with a scalpel handle and arranged in the ready condition with the blade exposed. 
           [0020]      FIG. 6  is a cross-sectional view of the blade and sheath of the present invention in ready position. 
           [0021]      FIG. 7  is an exploded cross-sectional view of the interlocking mechanism when the sheath is in the ready position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    Referring to  FIG. 1 , there is shown a perspective view of one embodiment of the blade and sheath of the instant invention together with a scalpel handle. 
         [0023]    In particular, the scalpel handle  1  is of conventional shape and configuration. This handle is made of plastic, stainless steel or other suitable material and of such nature that can withstand all types of sterilization ranging from chemical to heat (both dry or wet) or any other sterilisation. Typically, the distal end  14  on the tail  9  is relatively thin while the gripping or middle portion  11  is somewhat thicker. The front end  12  of the scalpel handle generally takes the configuration of an extended nose  13  which is relatively narrow and includes a groove and projection  13  on at least one edge thereof for receiving a blade  2 . 
         [0024]    The scalpel handle  1  can taper in width towards the distal end  14  near the tail  9 . On at least one of the surfaces of the handle  1 , the scalpel handle includes a plurality of ridges/stoppers/buttons  5 ,  6  and  9  and slots/recess/groove  7  and  13 . 
         [0025]    Typically, the distal end  14  of the handle  1  is somewhat rounded for convenience. In addition, a shoulder  15  can be provided at the end of the scalpel adjacent to the inner end of the nose  13 . 
         [0026]    The sheath  3  is also disclosed. While not necessarily limited thereto, the sheath  3  is typically formed of a plastic material such as a conventional polymer material including but not limited to polystyrene, polycarbonate, polyurethane, polyethelene, phenol-formaldehyde resins, polybutylene and the like. 
         [0027]    As shown in  FIG. 1 , a plurality of substantially parallel, transverse strips  11  are provided across the outer surface of the sheath  3 . These strips (or ridges) can be raised or depressed areas in the body of the sheath  3 . The strips  11  provide additional traction or gripping surface for the user of the sheath  3 . 
         [0028]    An aperture or window  4  having a square shape is provided through the upper surface lower of the sheath  3 . The aperture  4  is shaped to include a button/stopper  5  in order to correspond, cooperate and lock with this first stopper  4  and second stopper  6  while enclosing the scalpel blade  2 . The second stopper  6  is provided just under the first stopper  4 . The second stopper  6  limits the movement of the sheath  3  relative to the scalpel handle  1  when in blocking position. 
         [0029]    A representative blade  2  is shown. The shape of the cutting edge of the blade and so forth are representative only. It is well known that there are many sizes, shapes and styles of scalpel blades. The invention described herein is intended to cooperate with virtually any blade shape. 
         [0030]    Typically, the blade  2  includes a slot  16  which is configured to cooperate with and engage the nose  13  of the handle  1 . Typically, the nose is inserted into the larger portion of the slot  16  and slid forward to engage the smaller end of the slot in the groove  17  in the nose  13 . 
         [0031]    In  FIG. 2 , scalpel blade  2  (not visible) is shown along with the position thereof relative to the sheath  3 . The blade  2  is stored within the sheath  3  for safe and secure handling thereof without a danger of harm to the handler of the blade. 
         [0032]      FIG. 3  illustrates the cross-sectional view of the sheath  3  in blocking position and completely covering the blade  2 . When the blade  2  (within sheath  3 ) is to be attached to handle  1 , the front end  12  of the handle is not covered by the sheath  3  and this sheath  3  is slid down on to the middle portion  11  of the handle. The elongated nose  13  of the handle  1  is inserted into and mates with the slot  16  in the blade in conventional fashion. The scalpel is now in armed and ready position. 
         [0033]    To disarm the scalpel without touching the exposed blade  2 , the sheath  3  that is resting on the middle portion  11  of the handle  1  is pushed smoothly forward or upwards from the middle portion  11  over the blade  2  till the sheath  3  completely covers the blade  3  and the forward motion of the sheath  3  is stopped by the engagement of the window  4  with first stopper  5  and second stopper  6  and the sheath  3  is then locked over the blade  2 . The blocked scalpel can be now kept safely for future use by the healthcare worker. 
         [0034]    Referring now to  FIG. 3 , there is shown by cross section the condition wherein the blade  2  is fully mounted onto the nose  12  of the handle  1 . The sheath  3  covers the blade  2  and portion of the scalpel handle  1 . When the cutting procedure is concluded, the sheath  3  is positioned over the blade  2  by sliding the sheath  3  back over the blade  2  into the position shown in  FIG. 2 . 
         [0035]    When the sheath  3  is returned to the position shown in  FIG. 2 , the blade  2  is covered and the scalpel device can be handled in any appropriate fashion without fear of an accidental cut therefrom. 
         [0036]    Referring to  FIG. 4  shows the exploded view of the locking mechanism of the sheath  3  with the scalpel handle  1 . First stopper  5  engages with the lower portion  19  of the window  4  thereby stopping the sheath  3  from slipping over the scalpel blade  2  after the sheath has completely enclosed and secured the scalpel blade  2 . So that the sheath does not slide down the handle  1  and continues to remain in blocking position, the second button/stopper  6  prevents the sheath  3  from sliding down by engaging with the base  18  of the sheath  3 . Therefore, the window  4 , the first stopper  5 , second stopper  6  and the base  18  of the sheath  3  form an interlocking mechanism to retain the sheath  3  in the blocking position. 
         [0037]    The second button/stopper  6  is made of an elastic material. The second stopper  3  can obviously be made of any material that has elastic properties. This second stopper  6  acts as a spring. During ready position of the sheath  3 , the second stopper  6  has radial tension typical of a spring that exerts against the opposing inner walls  20  of the sheath. When the sheath  3  is activated and eventually comes to rest in the blocking position, the second stopper  6  is freed from the inner wall  20  of the sheath  3  and the spring action or the radial tension causes the second stopper  3  to spring outwards. This outward spring movement of second stopper  6  results in providing a retaining means for the sheath  3  to remain in the blocking position. The exploded cross-sectional view in  FIG. 4  best explains the working of this second stopper  6 . 
         [0038]    Referring now collectively to  FIG. 5  and  FIG. 6  there is shown a view of the sheath  3  and blade  2  mounted on the nose  12  of the handle  1 . This view is to explain the construction and working of the scalpel when sheath  3  is in ready position. 
         [0039]    In  FIG. 5  with the sheath  3  retracted to expose the blade  2  for any suitable cutting purposes or when it is desired to remove the blade  2  from the handle  1 , the sheath  3  is moved back over the blade and onto the handle (as shown in  FIG. 5 ). It is understood that the blade  2  is securely fastened to the scalpel handle  1  as described above. The sheath  2  has been withdrawn along the handle  1  by exerting pressure on the grip  11 . Typically, the grip  11  is operated by pulling downward thereon by the user&#39;s thumb and index finger or any other finger and then by the insertion of the handle  1  into the sheath  3 . 
         [0040]    It can be seen that the blade  2  is attached to the handle  1  but is completely exposed and ready for use or already used, as the situation may be. The sheath  3  in the ready position and is resting on the middle portion  11  of the scalpel handle  1 . The sheath  3  is comfortably mounted on the middle portion  11  of the handle  1  in such a position that the sheath  3  forms a part of the middle portion  11  of the handle  1 . So that the sheath  3  does not slide off the handle  1 , the handle is provided with stopper  8  on the end proximal to the curved distal end of the handle. This stopper  8  is in form of a projection from the surface of the handle  1 . Indeed, this embodiment also envisages instead of a projection, the stopper  8  can be in form of a recess or groove cut into the surface of the handle  1  which interacts and mates with projections from inside the inner walls  20  of the sheath  3 . 
         [0041]    This position of the sheath  3  enables the scalpel with blade  2  can be used easily and effectively without any requirement to remove the sheath  3  from the handle  1  and can indeed be slid into blocking position quite easily. 
         [0042]    To unsheathe the blade  2 , the sheath  3  can be pushed back and downwards over the body of the handle  1 . In this case, the force inserted on the sheath is sufficient to override the restraint caused by the button  6 . In the preferred embodiment, the button  6  which is made of elastic material and has radial tension directed inwardly relative to the sheath  3  (see  FIG. 7 ) and engages the sheath  3 . This arrangement provides additional security to prevent the sheath  3  from inadvertently sliding back over and covering the blade during a cutting procedure. 
         [0043]    The length of the sheath  3  is such that it just covers the first button  5  while resting on button  8 . Furthermore, the length of the sheath  3  is such that it completely covers the blade  2 . Such a construction assists in the preferred working of the sheath  3  but does not necessarily mean that other combinations are not possible. 
         [0044]      FIG. 7  shows the exploded cross-sectional view of the sheath  2  in ready position. This figure shows the close up and clear picture of the working of button  6  and the radial tension extending outwards into the interior wall  20  of the sheath  3 . 
         [0045]    Thus, there is shown and described a unique design and concept of a scalpel blade cover. While this description is directed to a particular embodiment, it is understood that those skilled in the art may conceive modifications and/or variations to the specific embodiments shown and described herein. Any such modifications or variations which fall within the purview of this description are intended to be included therein as well. It is understood that the description herein is intended to be illustrative only and is not intended to be limitative. Rather, the scope of the invention described herein is limited only by the claims appended hereto.