Abstract:
An improved needle design is cut diagonally from two sides to form a sharpened cutting edge, rather than a point. The needle has an external diameter and wall thickness sufficient to provide the rigidity necessary to punch the egg shell while the sharpened edge provides a sharp cutting edge able to sever the underlying membrane cleanly and penetrate an embryo if necessary. The needle&#39;s penetrating edge design prevents needle tip fold-over and the resulting formation of a hook which can lead to cross-contamination of eggs and shortened needle life.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention is related to the field of improved needle designs for in ovo vaccination and, more particularly, to a combined punch and needle design for use with an automated egg injection machine. 
         [0003]    2. Description of the Related Art 
         [0004]    Needles used for injection of vaccines are typically cut diagonally from one side to the other. This creates a sharp point suitable for penetrating relatively soft surfaces such as human skin. 
         [0005]    The process of in ovo vaccination, on the other hand, requires that a needle penetrate two surfaces, each having distinct qualities which creates mechanical challenges. The egg shell is hard, rigid, brittle and abrasive, while the membrane within the shell is soft, moist and pliable. The typical needle with its diagonal cut and sharp point is suited for penetrating the membrane but not for repeated punching of hard, brittle egg shells. 
         [0006]    Due to the differences in these two surfaces, the principal prior art approach utilizes a dual punch-needle system having an injection needle inside another needle which acts as a punch. Examples of such systems are disclosed in U.S. Pat. Nos. 5,056,464 and 5,136,979. The external needle (or punch) has a larger diameter to make it stronger and therefore capable of penetrating the egg shell multiple times before reaching a failing point. The internal needle has a smaller diameter and is sharper to facilitate membrane penetration. The internal needle cannot be used to penetrate the egg shell because the smaller-diameter tip will fold over upon impact and form a hook or “J” shape, i.e., needle tip fold-over. The same needle tip fold-over will also be imparted to the external needle after significant use, as representatively shown in drawing  FIGS. 1 ,  2  and  2 A. As shown, over time and repeated egg shell penetration, the leading edge  10  of the needle  12  becomes distorted, forming the hook  14  and increasing the force necessary to pierce the egg shell. 
         [0007]    While this dual punch-needle system makes the in ovo process possible, it is not without its challenges. For one, as stated above, the larger external needle or punch will begin to take on the “J” shape after significant use. If the distorted needle then punches a contaminated egg, the hook will entrap the contaminant and carry it to the next several eggs. This same hook also has the potential to lift eggs as the punch retracts and to thereafter drop them on top of other eggs, thus damaging and/or contaminating other eggs. 
         [0008]    Another challenge arises from the wear and tear suffered by the smaller diameter inner needle due to friction between the adjacent rubbing surfaces of the two needles. This wear and tear can lead to inner needles that bend easily during the injection process. The life expectancy of the larger diameter outer needle or punch is also compromised and, while dependent upon egg shell quality and quantity of eggs punched, is typically only one to two weeks. 
         [0009]    Furthermore, the space between the two adjacent needle surfaces traps pathogens and contamination and is difficult to sanitize and decontaminate. The sanitation process designed to take care of this condition does not have sufficient volume or pressure to properly disinfect this sensitive area. Instead, the sanitation fluid will travel the path of least resistance, leaving areas where the needles are tangent without sanitation, thus providing another source of cross-contamination. 
         [0010]    In an effort to address the above considerations, the assignee of the present invention developed a needle design having a blunt tip  16  as shown in  FIGS. 3 and 4 . This prior art needle design has been used on the INTELLIJECT® automated egg injection machine made and marketed by AviTech, LLC of Salisbury, Md. The needle is cut at an angled surface such that one side of the needle is longer than the other, with the angled surface being on the order of about 60° relative to the inside surface of the needle lumen adjacent the longer side. Instead of having the angled surface extend completely across the full width of the needle, the longer side of the needle is cut perpendicular to the length of the needle to form the blunt tip  16 . The blunt tip  16  makes initial contact with the egg and, having a thickness of between about seven and thirteen thousands of an inch (0.007″ to 0.013″), provides a sufficiently strong surface of impact to prevent needle tip fold-over. 
         [0011]    However, in addition to the negative impact of needle tip roll-over on needle life and sanitation, it is also believed that use of the foregoing prior art needle designs can present significant risk to the developing avian embryos. 
       SUMMARY OF THE INVENTION 
       [0012]    In order to overcome the foregoing drawbacks of the prior art, as well as other problems and disadvantages of prior art needle designs, the present invention seeks to provide an improved needle design for a pneumatically operated injection assembly of an automated egg injection machine such as disclosed in U.S. Pat. No. 7,185,603 (“the &#39;603 patent”), the disclosure of which is expressly incorporated herein by reference as if fully set forth. The improved needle design is directed to an injecting tip which is cut diagonally from two sides to form a sharpened cutting edge, rather than a point, enabling the needle to effectively penetrate both the egg shell and the underlying membrane while providing an extended needle life. The needle has an external diameter and wall thickness sufficient to provide the rigidity necessary to punch the egg shell while preventing needle tip fold-over and the resulting formation of a hook. In addition, the cutting edge forming the tip is sharpened with a combination of angles that not only provide additional resistance to needle tip fold-over but also provide a sharp cutting edge to pierce an 18 day embryo so as to avoid embryo flip, even if contact is made. 
         [0013]    Accordingly, it is an object of the present invention is to provide a single needle which can be used in the injection assembly of an automated egg injection machine to penetrate both the egg shell and the underlying membrane. 
         [0014]    Another object of the present invention is to provide a needle in accordance with the preceding object for use in a pneumatically operated injector and which has a tip in the form of an edge that is sharpened with multiple angles to prevent bending or needle tip fold-over. 
         [0015]    A further object of the present invention is to provide an egg injection machine needle in accordance with the preceding objects and which is able to penetrate both the egg shell and the underlying membrane and pierce the embryo so as to minimize or eliminate embryo flip in 18 day old embryos. 
         [0016]    Yet another object of the present invention is to provide an egg injection machine needle in accordance with the preceding objects and which reduces the risk of cross contamination between eggs. 
         [0017]    A still further object of the present invention is to provide an egg injection machine needle in accordance with the preceding objects and which has an angled edge cut from two sides to form the tip, the edge providing both sharpness and strength, resulting in extended needle life. 
         [0018]    These and other objects of the invention, as well as many of the intended advantages thereof, will become more readily apparent when reference is made to the following description taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a perspective view of a conventional prior art needle after sufficient use to form a hook on the leading edge of the tip. 
           [0020]      FIG. 2  is a side view of the needle of  FIG. 1 . 
           [0021]      FIG. 2A  is a detailed view of area “A” of  FIG. 2 . 
           [0022]      FIG. 3  is a perspective view of another needle design known in the art having a blunt leading edge to resist needle tip fold-over. 
           [0023]      FIG. 4  is a side view of the needle of  FIG. 3 . 
           [0024]      FIG. 5  is a perspective view of a needle tip having an angled edge in accordance with a first embodiment of the present invention. 
           [0025]      FIG. 6  is a side view of the needle tip of  FIG. 5 . 
           [0026]      FIG. 7  is an end view taken along line  7 - 7  of  FIG. 6 . 
           [0027]      FIG. 8  is another perspective view of the needle tip of  FIG. 5 . 
           [0028]      FIG. 9  depicts a needle tip having diagonal cuts in the lower angular range at 22.50° to produce a cutting edge having an angle of 45° in accordance with the present invention. 
           [0029]      FIG. 10  depicts a needle tip having diagonal cuts in the upper angular range at 45° to produce a cutting edge having an angle of 90° in accordance with the present invention. 
           [0030]      FIG. 11  depicts a needle tip having diagonal cuts of 30° to produce a cutting edge having a preferred angle of 60° in accordance with the present invention. 
           [0031]      FIG. 12  is a side view of a needle tip having an angled edge in accordance with a second embodiment of the present invention and incorporating the preferred angle of  FIG. 11 . 
           [0032]      FIG. 13  is a perspective view of the needle tip of  FIG. 12 . 
           [0033]      FIG. 14  is an end view taken along line  14 - 14  of  FIG. 12 . 
           [0034]      FIG. 15  is another perspective view of the needle tip of  FIG. 12 . 
           [0035]      FIG. 16  is a perspective view of a needle tip having an angled edge in accordance with a third embodiment of the present invention. 
           [0036]      FIG. 17  is another perspective view of the needle tip of  FIG. 16 . 
           [0037]      FIG. 18  is a side view of the needle tip of  FIG. 16 . 
           [0038]      FIG. 19  is an end view taken along line  19 - 19  of  FIG. 18 . 
           [0039]      FIG. 20  is a perspective view of a needle tip having an angled edge tip in accordance with a fourth embodiment of the present invention. 
           [0040]      FIG. 21  is a side view of the needle tip of  FIG. 20 . 
           [0041]      FIG. 22  is an end view taken along line  12 - 22  of  FIG. 21 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0042]    In describing preferred embodiments of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. 
         [0043]    The present invention is directed to a needle for use with an automated egg injection machine such as the INTELLIJECT® automated egg injection machine manufactured and marketed by the assignee of this invention. An early version of the INTELLIJECT® machine is disclosed in the &#39;603 patent previously incorporated by reference. The needle has an injection tip that is cut diagonally from two sides to form a cutting edge. The cutting edge forms the egg-contacting surface which, because of its width as compared with conventional pointed tips, demonstrates improved durability and punch capability as compared with prior art designs. 
         [0044]    According to a first embodiment as shown in  FIGS. 5-8 , the present invention is directed to a needle or cannula  20  having a lumen  21  and a tip generally designated by the reference numeral  22 . The tip  22  has an angled surface  24  formed by cutting the majority of the tip at a first oblique angle. This results in the needle having a short side  26  and a long side  28 . However, unlike the perpendicular cut of the long side as in  FIGS. 3 and 4 , only a portion  30  of the long side is cut at an angle different from the slope of the angled surface  24 . This portion  30  is cut at a second oblique angle relative to the needle sides so as to form an acute angle with the surface  24 . This acute angle creates a sharp leading or cutting edge  32  on the tip  22  of the needle. As the initial contact surface with the egg, the sharp cutting edge  32  penetrates the egg shell easily, reducing the force required to pierce the shell and thus, in turn, reducing shock to the egg and preventing embryo flip in 18 day old embryos. The sharp cutting edge  32  also distributes the wear associated with repeated egg contact across a greater surface area than with the pointed tips known in the prior art. 
         [0045]    The needle  20  in  FIGS. 5-8  should have an external diameter between about forty thousands of an inch (0.040″) and about seventy thousands of an inch (0.070″), preferably about fifty thousands of an inch (0.050″). The needle  20  should preferably have a wall thickness of approximately ten thousands of an inch (0.010″) within normal manufacturing tolerances (+/−0.002″), i.e., 0.008 inches to 0.012 inches. This structural strength, combined with the sharpened edge  32 , virtually eliminates the possibility of needle tip fold-over and “J” shape formation. Needle tip fold-over is further prevented by the angle at which the surface  24  is cut relative to the second angle at which the portion  30  is cut. As illustrated in  FIGS. 9-11 , the two diagonal cuts preferably can vary in angle from about 22.5° to about 45° with a more preferred angle being on the order of about 30° such that the acute angle between the angled surface  24  and the portion  30  cut at the second angle can vary in angle from about 45° to about 90°, with a more preferred angle being on the order of about 60°. 
         [0046]    A second embodiment of the present invention is shown in  FIGS. 12-15 . As in the first embodiment, an angled surface  25  is formed by cutting the majority of the tip at a first oblique angle, creating a short side  36  and a long side  38 . A portion  31  of the long side  38  is cut at a second oblique angle so as to form an acute angle with the angled surface  25 . The portion  31  cut at the second angle in the embodiment shown in  FIG. 12-15  is larger than in the first embodiment. This creates a leading edge  33  on the tip of the needle that is offset from the longitudinal axis  56  of the lumen  21  and tangent to the inner diameter  37  of the lumen  21  adjacent the long side  38 . 
         [0047]    A third embodiment of the present invention is shown in  FIGS. 16-19 . As in the first and second embodiments, an angled surface  44  is formed by cutting the majority of the tip, generally designated by reference numeral  42 , at a first oblique angle, creating a short side  46  and a long side  48 . A portion  50  of the long side  48  is cut at a second oblique angle so as to form an acute angle with the angled surface  44 . The portion  50  cut at the second angle is larger than in the first and second embodiments. This creates a leading edge  52  on the tip  42  of the needle that has two cutting portions  52   a ,  52   b  spaced from one another by a portion of the lumen  21 . The intersection of the portion  50  and the angled surface  44 , including the two cutting portions  52   a ,  52   b , is offset from the inside diameter  47  of the lumen on the long side  48  and also from the longitudinal axis  56  of the lumen  21 . 
         [0048]    A fourth embodiment of the present invention is shown in  FIGS. 20-22 . As shown, the tip, generally designated by reference numeral  62 , of the needle is cut at two oblique angles intersecting along the longitudinal axis  56  of the lumen to form opposing angled surfaces  64  and  66  of approximately equal size and slope. The preferred angle of slope for both surfaces  64 ,  66 , with respect to the longitudinal axis  56 , is on the order of about 30°, resulting in an angle between the surfaces of about 60°. Because the surfaces  64 ,  66  intersect along the longitudinal axis  56 , the leading edge  72  of the needle tip  62  has two cutting portions  72   a ,  72   b  spaced from one another by the diameter of the lumen. These two cutting portions  72   a ,  72   b , being on opposing sides of the needle wall, provide both a very sharp and an extremely durable impact surface. 
         [0049]    As with the first embodiment, the needles according to each of the second, third and fourth embodiments also should have an external diameter between about forty thousands of an inch (0.040″) and about seventy thousands of an inch (0.070″), preferably about fifty thousands of an inch (0.050″), and should preferably have a wall thickness of approximately ten thousands of an inch (0.010″) within normal manufacturing tolerances (+/−0.002″), i.e., 0.008 inches to 0.012 inches. 
         [0050]    The manner of sharpening the needle tip to form a leading edge that spans part or all of the needle width as just described results in a needle having the strength to punch through the egg shell and the sharpness to penetrate the membrane and the embryo so as to avoid flipping an embryo at only 18 days old. This construction also results in reduced contamination, otherwise caused by entrapment areas created when the needle tip is deformed, and a longer needle life. 
         [0051]    Other angles and angle combinations may also be implemented on the needle tip as long as the penetrating surface remains an edge rather than a point that could potentially fold and form a hook after repeated contact with the egg shell. Hence, the minimum condition is to cut the needle to an extent equal to a part of the width or thickness of the needle wall. 
         [0052]    The foregoing descriptions and drawings should be considered as illustrative only of the principles of the invention. The invention may be configured in a variety of shapes and sizes and is not limited by the dimensions of the preferred embodiment. Numerous applications of the present invention will readily occur to those skilled in the art. Therefore, it is not desired to limit the invention to the specific examples disclosed or the exact construction and operation shown and described. Rather, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.