Abstract:
A device for making an incision in skin, having a housing with a slotted opening, and a triggering mechanism disposed within the housing for propelling a blade coupled thereto, through the slotted opening of the housing to make an incision in the skin. The triggering mechanism includes a finger engageable trigger located external to the housing for actuating the triggering mechanism and a spring anchoring assembly for automated machine arming the device after the triggering mechanism has been assembled into the housing.

Description:
RELATED APPLICATIONS 
     International Technidyne Corporation, the assignee herein, is record owner of U.S. patent application Ser. No. 08/866,172 entitled ADJUSTABLE SKIN INCISION DEVICE, filed on May 30, 1997, and issuing as U.S. Pat. No. 5,797,940 on Aug. 25, 1998 by Mawhirt et al. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to blood drop generation devices for making incisions in skin and more particularly to a blood drop generation device having a compression spring assembly for after assembly access to the blade triggering mechanism. 
     BACKGROUND OF THE INVENTION 
     Blood drop generation devices are well known in the art for providing blood samples which are used in performing various blood tests for preventative medicine and medical diagnosis. Such devices operate by creating a small puncture or incision in the skin of the fingertip or other area of the body such as the foot, arm, or leg. 
     Since most blood drop generation devices employ a lancet-like structure for puncturing or incising the skin, blood drop generation devices are often referred to as lancet devices. Many prior art lancet devices employ spring loaded cutting blades which are enclosed within a casing or housing. These devices are operated by placing the housing of the device against the skin and triggering the spring loaded cutting blade in the device. The potential energy stored within the spring accelerates the blade through an aperture in the housing and creates a uniform puncture or incision in the skin. The structural configuration of these devices enable the puncture or incision in the skin to be made in a controlled manner in terms of location, size, depth, and sterility. Since the blade is concealed within the housing, the patient is unable to view the blade prior to, or during the puncturing of the skin which reduces the patient&#39;s anxiety. Further, most recent designs of lancet devices include means for retracting the blade back into the housing after the puncture or incision has been made. Such a safety feature advantageously reduces the probability of a disease being spread through contact with the used blade of the device. This is an important feature since, deadly viruses such as AIDS and Hepatitis can spread from accidental punctures obtained from lancets used previously on an infected patient. 
     As already mentioned, the structural configuration of a lancet device enables it to puncture or incise the skin in a controlled manner in terms of location, size and depth. Devices which puncture the skin employ cutting blades which plunge perpendicularly into the skin to produce a skin incision of a predetermined depth. Such lancets are exemplified in U.S. Pat. No. 5,133,730 to Biro. In U.S. Pat. No. 5,133,730, a sharp blade is provided on a spring biased pivot arm which moves the blade out through an orifice in the lancet housing and then retracts the blade back into the housing. Although the blade is positioned on a pivot arm, the blade is directed perpendicularly, into the surface of the skin. The shape of the blade helps the blade enter the skin and make the needed incision. Other lancet devices that create plunge-type cuts are described in U.S. Pat. No. 3,760,809 to Cambell, Jr. and U.S. Pat. No. 5,395,388 to Schrage. 
     Lancet devices which incise the skin employ cutting blades which move in an arcuate motion or cutting blades which move simultaneously in a perpendicular and transverse motion. The lancet devices employing cutting blades that incise the skin in an arcuate manner are exemplified in U.S. Pat. No. 3,902,475 to Berg et al. The lancets in U.S. Pat. No. 3,902,475 produce skin incisions that vary in depth along the length of the incision. Consequently, in order to obtain a requisite incision depth of between 1 and 5 mm, such lancet devices must produce incisions that are relatively long and thus, less desirable. 
     The lancet devices employing cutting blades that incise the skin in a simultaneous perpendicular and transverse motion are capable of producing skin incisions which are uniform in depth along the entire length of the incision. Such a lancet device is described in U.S. Pat. No. 4,643,189 to Mintz. The simultaneous perpendicular and transverse motion of the cutting blade is accomplished by providing a unique cam configuration which controls the path of a pivoting arm that contains a cutting blade. The cutting blade is powered by a looped straight-arm torsion spring which is installed when the lancet device is assembled. 
     SUMMARY 
     A device for making an incision in skin, comprising a housing having a slotted opening and triggering means disposed within the housing for propelling a blade coupled thereto, through the slotted opening of the housing a given distance to make an incision of a predetermined size in the skin. The triggering means includes separate spring biasing means for arming the device after the triggering means have been assembled into the housing. 
     In another embodiment, the triggering means includes an arm link which couples the blade, the spring biasing means rotating the arm link when the device is activated to propel the blade through the slotted opening of the housing when the device is activated. In a further embodiment, the removable spring biasing means includes a coil spring that engages the arm link. 
     In still another embodiment, the separate spring biasing means and the housing include bayonet locking means for retaining the separate spring biasing means to the housing after complete assembly of the remaining parts; the housings, the blade holder and the triggering means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a detailed understanding of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings wherein: 
     FIG. 1A is an elevational view of a lancet device in accordance with an embodiment of the present invention; 
     FIG. 1B is a side elevational view of the lancet device of FIG. 1A without a spring and spring anchor assembly installed; 
     FIG. 1C is a side elevational view of the lancet device of FIG. 1A with the spring and spring anchor assembly installed; 
     FIG. 2A is an exploded perspective view of an embodiment of the spring anchor assembly; 
     FIG. 2B is a side elevational view of the spring anchor assembly of FIG. 2A; 
     FIG. 3A is a cross-sectional view of the lancet device of FIG. 1A in the armed position prior to activation; and 
     FIG. 3B is a cross-sectional view of the lancet device of FIG. 1A, after the device has been activated. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1A, an elevational view of a lancet device according to an exemplary embodiment of the present invention is shown and denoted by the numeral  10 . The lancet device  10  is especially suited for making skin incisions in the heel of newborn infants, however, the lancet device of the present invention is also suited for making skin incisions in toddlers, children and adults. The lancet device  10  is based on the lancet device described in U.S. Pat. No. 4,643,189. Accordingly, the teachings of this patent as they apply to the present invention, are incorporated herein by reference. 
     Referring still to FIG. 1A, the lancet device  10  comprises a housing  12  molded from any suitable plastic. The housing  12  encloses a blade triggering mechanism that is activated by pushing a trigger  14  as will be explained. The spring anchor head member  16  is located on a first side  18  of the housing  12 . 
     In FIGS. 2A and 2B, the head member  16  is a component of a spring anchor assembly  26  that is designed to be machine installed within the housing  12  after the lancet device  10  has been assembled with all internal components in the armed position. The spring anchor assembly  26  comprises a dual tab, headed spring anchor  28  and a coil spring  36 . The thumb-screw  28  is unitarily formed to include the machine interfacing rotatable head member  16  and a centrally located cylindrical-shaped shaft member  30 . A pair of radially extending locking tabs  32  are disposed  180  degrees apart from each other on the shaft  30  at the marginal end thereof. The back sides of the tabs  32  and the end portion  34  of the shaft  30  form spring seat for the compression coil spring  36 . 
     In FIG. 1B, a side view of the lancet device  10  of FIG. 1A, is depicted without the spring anchor assembly  26  installed therein. As can be seen, the side  18 A and  18 B of the housing  10  includes an installation aperture  20  for removably receiving the spring anchor assembly  26 . The aperture  20  is formed half in  18 A and  18 B. The installation aperture  20  has a circular-shaped opening  22  with a pair of slots  24  disposed  180  degrees apart from each other. The slots  24  of the installation aperture  20  and the locking tabs  32  of the headed spring anchor  28  coact to define a one-quarter turn bayonet-style spring anchor assembly locking arrangement as illustrated in FIG.  1 C. The locking tabs  32  engage the recesses of the slots  24  to permanently secure the spring anchor and to further provide separation resistant grips to the housing halves,  18 A and  18 B. 
     As is visible in the cross-sectional view of FIG. 3A, the spring anchor assembly is one of the components of the earlier mentioned blade triggering mechanism  38 . The other major components of the blade triggering mechanism  38  include the trigger  14 , the user removable safety  14 A, a blade holder/follower  40  which holds a triangular cutting blade  42 , and a cam channel  44 . The blade triggering mechanism  38  is depicted in FIG. 3A in an armed position after the installation of the spring anchor assembly  26 . The trigger  14  is a plunger-like device that is moveable in the direction of arrow  48  in a channel  46  defined by the housing  12 . The channel  46  has a projecting boss  50  that holds the trigger  14  in the armed position before activation of the lancet device  10 . 
     The blade holder/follower  40  of the blade triggering mechanism  38  has a detent or notch  56  at a first end  52  thereof. The triangular blade  42  with a cutting edge  58  and sharpened apex  60 , is disposed at a second end  54  of the blade holder/follower  40 . The blade  42  may be secured to the arm link  40  by any conventional means and is scalpel-like in appearance and function. An elongated slotted opening  78  through which the blade  42  is directed, is provided in the base  76  of the housing  12 . The blade holder/follower  40  includes an elongated aperture  62  which allows the blade holder/follower  40  to simultaneously rotate and reciprocate on a pivot shaft  64  defined on an inner surface  66  of the housing  12 . The blade holder/follower  40  also includes a cam follower  68  (shown in broken lines) disposed marginally adjacent to the first end  52  thereof. The cam follower  68  follows the specially profiled cam channel  44  defined on the inner surface  66  of the housing  12 , which causes the blade holder/follower  40  to simultaneously rotate and reciprocate according to the profile of the cam channel  44  when the device is activated. The detent  56  of the blade holder/follower  40 , coacts with the end  70  of the trigger  14  to retain the blade holder/follower  40  in the armed position. The blade holder/follower  40  also includes a notched area  72  with a centrally located protrusion  74  which accommodates and grips the free end of the coil spring  36  of the spring anchor assembly  26 , when the spring anchor assembly  26  is installed in the housing  12  to arm the lancet device  10 . With the spring anchor assembly  26  installed, the coil spring  36  is compressed between the thumb screw  28  and the locked blade holder/follower  40 . 
     When the lancet device  10  is activated, the operator removes the safety  14 A and pushes the trigger  14  in the direction of the arrow  48  which pushes the first end  52  of the blade holder/follower  40  toward the end wall  18  of the housing  12  until the end  70  of the trigger  14  disengages from the detent in the blade holder/follower  40 . At this position, the energy stored in the compressed spring  36  (which is now almost fully compressed) is released and drives and rotates the blade holder/follower  40  in the direction of arrow  80  thus, causing the cutting edge  58  of the blade  42  to move out of the housing  12  through the elongated aperture  78  in the direction indicated by arrows  84 ,  82 ,  84 A with the arm link&#39;s motion being controlled by the profile of the cam channel  44 . More specifically, the cam channel  44  causes the blade holder/follower  40  to first rotate in the direction of the arrow  82  and then move linearly in the direction of arrow  84  which causes the apex  60  and cutting edge  58  of the blade  42  to immediately more vertically from the housing  12  through the elongated slot  78  a predetermined distance as determined by the profile of the cam channel  44  to puncture the skin. The vertical motion  84  permits instantaneous full penetration of the incision blade  42 . With the cutting edge  58  of the blade  42  in the skin, linear movement in the direction of arrow  84  is virtually halted, and rotation of the arm link  40  continues on for a predetermined number of degrees as controlled by the cam channel  44  which produces an incision of a uniform depth as depicted by the blade cut path  86  shown in FIG.  3 B. Then, the profile of the cam channel  44  causes the blade holder/follower  40  to move linearly in the direction of the arrow  84 A to vertically withdraw the blade  42  from the skin and back into the housing  12  through the elongated slot  78 . The vertical withdrawal eliminates tissue tearing at the end of the incision. The faceted recess  16 A is configured to permit automatic insertion and rotation of spring anchor  28  with the spring  36  attached. Features molded into the case  18 , sides will guide the spring  36  onto the seating and gripping feature  74  of blade holder/follower  40 . 
     It will be understood that the embodiments described herein are merely exemplary and that a person skilled in the art may make many variations and modifications to the described embodiments utilizing functionally equivalent elements to those described. For example, other embodiments of the thumb screw can include more than two locking tabs with a correspondingly constructed installation aperture in the housing or any other type of well known screw thread arrangement. Any variations or modifications to the invention described hereinabove are intended to be included within the scope of the invention as defined by the appended claims.