Abstract:
A skin incision device including a housing having a bottom surface with a slot formed therein, a top positioned on said housing and slidable in a direction toward the bottom surface, a blade pivotally positioned in the housing adjacent said slot, and a spring cooperatively positioned between said top and an interior of the housing. The spring is actuatable by the slidable movement of said top toward the bottom surface of the housing. The spring moves the blade between a pre-actuated position and a post-actuated position.

Description:
RELATED U.S. APPLICATIONS 
   The present application claims priority from U.S. Provisional Patent Application Ser. No. 60/400,999, filed on Aug. 5, 2002, and entitled “Internal Actuator for Bleeding Time Testing Device”. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   REFERENCE TO MICROFICHE APPENDIX 
   Not applicable. 
   FIELD OF THE INVENTION 
   The present invention relates to medical devices. More particularly, the present invention relates to devices for incising the skin. In particular, the present invention relates to internal actuators for skin incising devices which apply a controlled load and a constant force during the incising operation. Additionally, the present invention relates to skin incising devices that are used for the purpose of blood acquisition. 
   BACKGROUND OF THE INVENTION 
   In the medical field, it is a very common procedure, and often very necessary, to conduct a bleeding time test which measures the time required for the cessation of bleeding following a skin incision. This test is medically important because extended or prolonged bleeding time can be associated with, for example, a lack of or a great excess of platelets, abnormality of platelet function, coating of platelets by specific proteins or foreign materials or the action of certain drugs; e.g., aspirin. 
   Although the bleeding time test procedure was first described approximately ninety years ago, it did not receive general acceptance until the 1940&#39;s at which time the test&#39;s sensitivity was increased by making a skin incision on the forearm of the patient while maintaining a blood pressure cuff inflation to maintain venostasis at a standardized level. Using this procedure, a technologist simultaneously starts a stopwatch while making the incision. The emerging blood is then gently blotted every thirty seconds. The cessation of bleeding is defined as the time at which the blotting paper is no longer stained by the emerging blood. This amount of time is generally recorded to the nearest half minute. 
   Disposable bleeding time devices were first introduced in 1978 to facilitate automation and convenience. These devices improved the acceptance of the test by both the patient and the operator. However, the results were still subject to a variety of technical variables. Additionally, these devices were significantly more expensive than previous methods. This hindered the acceptance of such devices in many countries around the world. Importantly, different disposable devices evolved over time which were functionally quite dissimilar so that the results were not comparable. Thus, standardization remained an elusive goal in bleeding time testing. 
   An important bleeding time testing device is known as the TRIPLETT™ bleeding time testing device. This was named after the noted physician in blood coagulation and hematopathology, Dr. Douglas Triplett. This device is presently manufactured and sold by Helena Laboratories of Beaumont, Tex. This device met the goal of global standardization in bleeding time testing and utilizes advanced technology at a universally affordable price. This was a product that provided a new level of value to automated, disposable bleeding time devices. This TRIPLETT™ bleeding time testing device was designed to be user and patient friendly, virtually painless, and to mimic the incision motion of the original bleeding time method. The device makes a standardized surgical incision one millimeter deep by five millimeters long for accurate sensitive bleeding time testing. The blade automatically retracts after incisions so as to ensure safety. The device includes a large contact surface that distributes the downward force over a wider area of skin so as to reduce the potential for deep non-standardized cuts. This device is presently subject to patent protection under U.S. Pat. Nos. 5,662,672 and 5,733,300. 
   Various other U.S. patents have issued relating to such bleeding time testing devices. For example, U.S. Pat. No. 4,064,871, issued on Dec. 27, 1977 to W. J. Reno, teaches a bleeding time testing device that includes a housing having a surface with a slot defining a longitudinal opening into the housing. A blade is mounted within the housing for movement of the blade tip through and along the slot. Biasing springs are provided within the housing to urge the blade through the slot a predetermined distance and along the slot for a predetermined length to control the depth and length of an incision produced with the device. A trigger is provided to initiate movement of the blade along with a safety pin to prevent the inadvertent activation of the device. 
   U.S. Pat. No. 4,628,929, issued on Dec. 16, 1986 to Intengan et al., describes another type of retractable bleeding time testing device. This device includes a housing, a hammer mechanism pivotally positioned within the housing and having a cam surface, and a self-retracting shuttle supported within the housing and including a cam follower surface. The shuttle is operative to travel in a vertical direction by the movement of the cam surface along the cam follower surface and the force exerted on the shuttle by a first spring extending from the shuttle. A cutting blade is secured to the shuttle and is operative to move out of the housing to make the incision and then to self-retract into the housing. A second spring is operative to exert a force on the hammer to cause it to move along the cam follower surface and to cause the shuttle to travel downwardly thus causing the blade to travel out of the housing to make the incision. The second spring is also operative to move into a locked position to secure the blade within the housing after the blade has retracted back into the housing. 
   U.S. Pat. No. 5,031,619, issued on Jul. 16, 1991, to F. Pompei, describes a method for determining bleeding time which includes a cutting assembly and a member for providing a compensation factor as a function of the temperature of the patient. The cutting assembly provides an incision of predetermined dimensions for external bleeding therethrough. The compensation member measures temperature of the patient throughout the period of external bleeding and provides a compensation factor as a function of the sensed temperature. 
   One of the problems associated with the use of the TRIPLETT™ device is that the force applied to actuate the device is off-center from the location at which the blade emerges from the cutting surface. As such, variations of pressures applied to the device can occur. As a result, the bleeding time testing can have a lack of consistent testing. Angular deflections of the cutting surface can also occur by the off-center application of pressure to the actuator of such cutting device. As such, a need has developed for a device for actuating such bleeding time testing devices such that the pressure of actuation will be directly above the location of the incision. 
   U.S. Application Ser. No. 60/393,971, filed on Jul. 5, 2002, by the present applicant, describes a constant force actuator for a bleeding time testing device. This constant force actuator is externally applied to an existing bleeding time testing device. The bleeding time testing device includes a body having a bottom surface from which a cutting blade can emerge so as to carry out an incision. The body includes a switch pin actuator that extends outwardly of the top surface in the testing device body. The switch pin is movable between a pre-actuating position and an actuating position. A safety tab is removably positioned between the switch pin actuator so as to retain the switch pin actuator in its pre-actuating position. The safety tab is to be removable so as to enable the testing device to be actuated by moving the switch pin from the pre-actuating position to the actuating position. The cutting blade is cooperative with the switch pin actuator to move outwardly of the bottom surface of the body of the testing device when the switch pin is moved to the actuating position. In this provisional patent application, a constant force device is mechanically attached to the surface of the body of the bleeding time testing device. The constant force device has a housing that is mounted onto the top surface of the bleeding time testing device so as to extend parallel to the bottom surface of the device. A suitable spring clip is provided on the housing so as to allow the actuator housing to be affixed to the body of the bleeding time testing device. A slide frame is mounted on the housing so as to be in slidable relationship to the housing. The slide frame is movable between a pre-activated position to an activated position. In the pre-activated position, the slide frame has a surface which resides against the switch pin actuator in the pre-activated position. A spring is mounted so as to be cooperative with the slide frame so as to urge the slide frame to the actuated position. An actuator button is slidably mounted on the housing so as to be slidable in a direction transverse to the plane of the bottom surface of the bleeding time testing device. When the actuator button is depressed, the spring associated with the slide frame urges the slide frame in a horizontal direction parallel to the bottom surface of the bleeding time testing device and thereby moves the switch pin actuator from the pre-actuating position to the actuating position. The actuator button is positioned directly above the center line of the cutting blade during the incision procedure. 
   It is an object of the present invention to provide a skin incision device that will not make the incision until a controlled vertical force is applied against the subject tissue. 
   It is another object of the present invention to provide a skin incision device that removes the variations of force that are applied by different operators at the time the incision is performed. 
   It is another object of the present invention to provide a skin incision device which allows the actuation force to be easily altered by a modification of a spring for the purpose of providing different actuating forces. 
   It is a further object of the present invention to provide a skin incision device which can be assembled with no force required to load the components which interact to produce the incision. 
   It is a further object of the present invention to provide a skin incision device in which the blade is propelled by a designed controlled interaction of internal components which creates a slicing into, across and slicing out of subject tissue for the purpose of minimizing the trauma to the subject tissue. 
   It is another object of the present invention to provide a skin incision device which reduces the introduction of undesirable components of the skin tissue into the incision area and blood sample. 
   It is still a further object of the present invention to provide a skin incision device that promotes rapid healing of the incision location. 
   It is still another object of the present invention to provide a skin incision device which has a concurrent action at the incision which locks the device and prohibits the ability of the device to be reloaded for additional uses. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention is a skin incision device that has a housing having a bottom surface with a slot formed therein, a top positioned on the housing and slidable in a direction transverse to the plane of the bottom surface, a blade pivotally positioned in the housing generally adjacent to the slot, and a spring cooperatively positioned between the top and an interior of the housing. The spring is actuatable by the slidable movement of the top toward the bottom surface. The spring is for moving the blade between a pre-actuated position and a post-actuated position such that at least a portion of the blade extends outwardly of the bottom surface through the slot during the movement between the pre-actuated position and the post-actuated position. 
   In the present invention, the housing has a generally open end opposite the bottom surface. The housing has sides which extend upwardly from the bottom surface. The top extends over the open end and over at least a portion of the sides of the housing. At least one of the sides of the housing has a barb extending outwardly therefrom. The top has a wall extending the side of the housing. The wall has a first retaining slot formed therein and a second retaining slot formed therein above the first retaining slot. The barb engages the first retaining slot when the spring means is in the pre-actuated position. The barb engages the second retaining slot when the spring means is in the post-actuated position. 
   In the present invention, the spring includes an actuator spring having an end cooperative with an inner surface of the top and extending downwardly into the housing, and a carriage element positioned within the housing. The actuator spring contacts a surface of the carriage element. The carriage element is movable within the housing for moving the blade between the pre-actuated position and the post-actuated position. The carriage element has one end affixed with the housing. The carriage element has a first jointed area formed thereon. The actuator spring has a opposite end in contact with the first jointed area. The carriage element has an opposite end connected to the blade. The carriage element is positioned in a guide area within the housing. The carriage element has a second jointed area formed thereon of a generally U-shaped construction. One end of the actuator spring is affixed to the inner surface of the top. In the preferred embodiment of the present invention, the actuator spring is a leaf spring. The actuator spring has a knuckle formed at an opposite end thereof. The carriage element also includes a retainer affixed to a surface of the carriage element. The knuckle is received within the retainer when the blade is in the pre-actuated position. The knuckle is separable from the retainer when the top moves toward the bottom surface of the housing. 
   In the present invention, the blade includes a razor member having a cutting edge and a cam connected to an end of the blade and positioned interior of the housing. The spring is cooperatively connected to the cam so as to pivotally move the razor member between the pre-actuated position and the post-actuated position. The housing has a blade retainer peg formed therein adjacent the slot. The blade is positioned onto the blade retainer peg. The blade is pivotally connected to the cam. The blade has an obround formed therein. The obround is positioned over the blade retainer peg. An abutment member is affixed within the housing and has surface contacting a surface of the cam as the razor member moves between the pre-actuated position and the post-actuated position. 
   In general, the present invention is a device for making a standard incision in skin tissue for the purpose of blood acquisition. The present invention is, in particular, related to bleeding time testing devices. The present invention is a single-use/disposable device which includes the slot for the purpose of allowing the blade to travel out of the device for the purpose forming the incision and then retracting back into the housing of the device. The movable top travels in a downward motion so as to apply an even pressure against the skin. The spring that is connected to the top is actuated when a controlled load limit is achieved. When a controlled load limit is achieved, the spring will release stored energy into a horizontal motion which transfers that motion onto the carriage element. As a result, the carriage element is moved horizontally. When the carriage element is moved horizontally, the geometry of the cam is introduced onto a fixed position peg. This introduction of the force causes a unique travel response by the carriage element which, in turn, transfers this travel response to the blade. The unique travel response of the blade propels the razor member out of the housing, through the skin, and back into the housing in a very controlled action. This controlled action of the razor member is such the razor member is slicing upon entry into the skin, guided horizontally while at depth, and slicing upon exiting the skin. This action of slicing, both entering and exiting, will minimize the trauma to the skin, will reduce the introduction of undesirable elements of the skin tissue into the incision and blood sample, and will promote the rapid healing of the incision location. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is an outer perspective view of the skin incision device of the present invention. 
       FIG. 2  is a cross-sectional view of the skin incision device of the present invention as shown in its pre-actuated position. 
       FIG. 3  is a cross-sectional view of the skin incision device of the present invention showing the device in its movement between the pre-actuated position and the post-actuated position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , there is shown the skin incision device  10  in accordance with the teachings of the preferred embodiment of the present invention. The skin incision device  10  includes a housing  12  having a bottom surface  14  and atop  16  slidably positioned on the housing  12 . The top  16  is slidable in a direction transverse to a plan of the bottom surface  14 . An indicator arrow  18  indicates the centerline of travel of the razor blade. 
   As will be described hereinafter, the housing  12  will have a generally open end opposite the bottom surface  14 . The housing  12  has sides  20  and  22  extending upwardly from the bottom surface  14 . The top  16  extends over the open end of the housing  12  and has a wall  24  extending over at least a portion of the side  20  of the housing  12 . The side  20  has a barb  26  extending outwardly therefrom. The wall  24  has a first retaining slot  28  and second retaining slot  30  formed above the first retaining slot  28 . As can be seen in  FIG. 1 , the barb  26  engages the first retaining slot  28 . 
   In  FIG. 1 , the device  10  is shown in its pre-actuated position. Ultimately, the bottom surface  14  will be placed upon the surface of the skin and the top  16  will be pressed downwardly toward the bottom surface  14 . As a result, the barb  26  will free itself from the first retaining slot  28 . When the device  10  has incised the skin and the blade is retained in its post-actuated position, the barb  26  will then be retained within the second retaining slot  30 . As a result, the barb  26  prevents reuse of the device  10 . Within the concept of the present invention, it is important to note that another barb can also be placed on the opposite side  32  of housing  12  so as to suitably engage corresponding retaining slots formed on the opposite wall  34  of the top  16 . 
     FIG. 2  shows a cross-sectional view of the device  10  of the present invention. In particular, in  FIG. 2 , it can be seen that the housing  12  has a slot  36  formed on the bottom surface  14  thereof. A blade  38  is positioned in the interior  40  of the housing  12  generally adjacent to the slot  36  and to the bottom surface  14 . The housing  12  also has a side  20  extending upwardly from the bottom surface  14  and another side  32  extending upwardly from the bottom surface  14 . A barb  26  is secured to the side  20  of housing  12 . Another barb  42  is secured to the side  32  of housing  12 . As can be seen in  FIG. 2 , the barb  26  engages the first retaining slot  28  on the wall  24  of top  16 . The barb  42  engages the first retaining slot  44  formed on the wall  34  of the top  16 . As a result, the top  16  will reside in its pre-actuated position. 
   In  FIG. 2 , it can be seen that an actuator spring  46  has an end  48  affixed to the inner surface  50  of the top  52  of housing  16 . The actuator spring  46  is a type of leaf spring which will extend downwardly in an arcuate manner through the open end  54  of the housing  12 . The opposite end of the actuator spring  46  has a knuckle  56  formed thereon. The actuator spring  46  can be suitably change, replace, altered, or otherwise manipulated so as to exert greater or lesser forces within the interior of housing  12 . 
   A carriage element  58  is positioned within the housing  12 . The actuator spring  46  is illustrated as being received within a retainer  60  secured at a first jointed area  62  on the carriage element  58 . The first jointed area  62  is a low shear, high tension joint. One end of the carriage element  58  is affixed to a pin  64  on the interior of housing  12 . 
   The carriage element  58  has a unique configuration within the housing  12 . In particular, the carriage element  58  includes a second jointed area  66  of a U-shaped construction received within a guide area  68 . Guide area  68  is defined by pegs  70 ,  72  and  74 . The end of the carriage element  58  is connected to the blade  38  so as to properly manipulate the blade, as will be described hereinafter. In the pre-actuated position, as shown in  FIG. 2 , the knuckle  56  of the actuator spring  46  is received within the retainer  60  so as to exert a desired force on the first jointed area  62  of the carriage element  58 . As a result, the blade  38  will be in its pre-actuated position entirely interior the housing  12  and adjacent to the slot  36 . 
   The blade  38  includes a razor member  76  formed at a lower end of the blade  38 . Additionally, a cam  78  is secured in pivotal relationship to the blade  38 . An obround  80  is formed in the blade  38  so as to be in generally pivotal and slidable relationship with a blade retainer peg  82 . An abutment member  84  is positioned within the housing  12  generally adjacent to the upper surface  86  of the cam  78 . In normal use, the abutment member  84  will reside adjacent to one edge of the surface  86  of cam  78 . When the device is suitably actuated, the abutment member  84  will travel along the surface  86  of cam  78  so as to cause the downward and incising movement of the blade  38 . A bounce control peg  88  is also formed within the interior of housing  12  so as to act as a guide for the carriage element  58  and to prevent outward bouncing of the razor member  76  when the device is actuated. 
     FIG. 3  shows the device  10  in its movement between pre-actuated position and the post-actuated position. In particular, in  FIG. 3 , it can be seen that the top  16  has been pressed downwardly upon the housing  12 . As a result, the barbs  26  and  42  will be received within the respective second retaining slots  30  and  90  of the top  16 . 
   Importantly, in  FIG. 3 , it can be seen that the actuator spring  46  has been suitably compressed by the downward movement of the top  16  relative to the bottom surface  14  of housing  12 . The actuator spring  46  will deflect by its contact with abutment peg  92 . The cantilever movement caused by the peg  92  will cause the knuckle  56  to be separated from the retainer  60 . Once released, the knuckle  56 , in combination with the actuator spring  46 , will exert a force on the carriage element  58  so as to cause the carriage element  58  to move toward the side  32  of housing  12 . This will also cause the carriage element  58  to press the opposite end inwardly. As a result, the surface  86  of cam  78  will travel along the abutment member  84  so as to create the outward movement of the razor member  76  of blade  38 . The bounce control peg  88  will prevent any accidental bounce or resilient movement of the razor member  76  outwardly of the slot  36 . 
   The operation of the present invention allows for a designed controlled force to be achieved. The top  16  will travel vertically over the housing  12 . The actuator spring  46  is restrained at one end by contact with the inner surface  50  of the upper surface  52  of top  16 . The opposite end of the actuator spring  46  is in contact with the top surface of the carriage element  58 . The top  16  will continue to travel downwardly and the vertical application force is retained in the actuator spring  46 . At a designed vertical pre-determined force, which is achieved as a function of distance traveled and spring flexing, the actuator spring  46  makes contact with the actuation peg  92 . When contact is made between the actuator spring  46  and the abutment peg  92 , the operator can continue to push down on the top  16 . As the top  16  continues to travel downwardly after contact with the actuation peg  92 , the peg  92  causes the knuckle  56  to rotate out of the retainer  60 . When the restrained knuckle  56  of the actuator spring  46  relocates past the top edge of the retainer  60 , the centerline of knuckle  56  is higher than the top edge of the retainer  60 . The vertical pre-actuation force is released in a horizontal motion, as shown in  FIG. 3 . This is controlled by the contact between the actuator spring  46  and the top edge of the retainer  60 . 
   The action described hereinbefore illustrates that a vertical force is appropriately transformed into a horizontal force on the interior of the housing  12 . The knuckle  56  of actuator spring  46  will begin to travel toward the nearest side  32  of the housing  12 . As the knuckle  56  travels horizontally, it will contact the carriage element  58 . In this encounter, the horizontal force will overpower one of the two, low shear/high tension joints  62  and  66  that are designed onto the carriage element  58 . When the horizontal force overpowers the jointed area of the carriage element  58 , the carriage element  58  begins to travel in a horizontal direction. The horizontal travel of the carriage element  58  is controlled by the various support pegs  70 ,  72  and  74  which define a guide path within the housing  12 . Once the carriage element  58  begins to travel horizontally, the cam  78  is forced to move in two directions simultaneously (i.e. vertically and horizontally) in order to release the force inputted into the carriage element  58  by the actuator spring  46 . The carriage element  58  is allowed to move vertically as a designed function of the second low shear/high tension joint  66  at the far right side of the carriage element  58 . As the carriage element  58  travels horizontally and vertically, one end of the blade  38  is carried along with the carriage element  58 . The surface  86  of cam  78  reacts with the abutment member  84  so as to move the blade  38  through a controlled horizontal and vertical motion. The blade  38  is allowed to move vertically by means of an obround  80  located on the body of the blade  38 . The blade  38  is controlled front to back by a shoulder entrapment designed into the blade retainer peg  82 . The carriage element  58  travels horizontally and vertically until such time as the energy is totally released from the interaction of the actuator spring  46  with the carriage element  58  or until the carriage element  58  is trapped against the side  32  of housing  12 . As such, the blade  38  is propelled through a horizontal/vertical trajectory out of and back into the slotted opening  36  at the bottom surface  14  of housing  12 . When this event occurs, a controlled slicing into, across and out of the skin should occur. A concurrent event also occurs at the same time. As described in previously, the barbs  26  and  42  will now engage the second retaining slots  30  and  90  on the walls  24  and  34  of the top  16 . As a result, the top  16  will be restrained in a fixed condition which prohibits reuse of the device. 
   The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can be made within the scope of the present invention without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.