1. Field of the Invention
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.
2. Description of the Related Art
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.
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.
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
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.
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.
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.
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
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.
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 '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.
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.
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.
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.
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.
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.
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.
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.
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 '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.
According to a first embodiment as shown in
The needle 20 in
A second embodiment of the present invention is shown in
A third embodiment of the present invention is shown in
A fourth embodiment of the present invention is shown in
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.
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.
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.
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.