Teat knife

A simplified unitary teat knife is formed of stainless steel rod with a knurled knob on one end and an eye on the other. The eye is flattened and enlarged relative to the rod of the knife and the edges of the eye are sharpened so as to provide cutting surfaces for removal of obstructions within the milk duct as the tool is rotated within the duct by manual manipulation of the knurled knob.

BACKGROUND OF THE INVENTION 
This invention relates to an instrument for removing unwanted obstructions 
in the milk duct of a cow teat which hinder or stop the flow of milk 
therethrough. More particularly, this invention is directed toward a 
simplified unitary knife structure for safely and thoroughly removing scar 
tissues, small floating cysts, tumors and the like from the interior of 
the milk duct of a cow's teat. 
In the dairy industry, it is not uncommon to encounter difficulty in 
obtaining milk from one or more teats of a particular cow. This is usually 
caused by an obstruction of scar tissue, membrane cartilage or other 
growth within the milk duct of the teat and severely curtails the milk 
production from the cow. Various devices have been proposed over the years 
for clearing the duct of the teat from these obstructions, with most of 
them being of the curette type for actually severing a growth from the 
lining of the milk duct to various multiple acting instruments for 
removing growths which have required manipulation of at least two elements 
requiring generally the use of two hands to affect the desired clearing of 
the milk duct. U.S. Pat. Nos. 1,837,503; 1,663,761; and 737,293 are 
typical of this type of apparatus where a hollow shaft has an aperture 
forming a cutting surface in the distal end and a rod positioned in the 
shaft interior has a cooperating surface for severing a protrusion 
captured by said aperture. The manipulation of the interior and the 
exterior actuating members usually requires two hands. Another approach 
has been that of U.S. Pat. No. 2,816,552 in which a set of knives is 
expanded by an internal threaded rod which expands flexible blades to an 
enlarged diameter so that the interior of the milk duct can be scrapped to 
enlarge same and remove undesired obstruction. Various veterinary knives 
have been proposed which can be manipulated to remove tissue from the 
interior of the milk duct of the teat and these are represented by U.S. 
Pat. No. 2,676,595. 
All of these prior art devices have been difficult to use or have required 
the expert services of a veterinarian to properly remove the obstruction 
without injuring the teat of the cow. While some of these devices have 
permitted removal of the obstruction, they have frequently caused 
additional injury to the teat and ultimately resulted in lack of milk 
flow, resulting in premature termination of the milking life of the cow. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is accordingly an object of the present invention to provide an improved 
teat knife that overcomes the limitations of the prior art. 
It is another object of the present invention to provide a simplified teat 
knife that can be easily and readily used by dairy farmers and 
veterinarians alike. 
It is another object of the present invention to provide a simplified, 
unitary construction of a teat knife that can remove obstructions, but 
will not accidentally gouge or otherwise damage the interior lining of the 
milk duct of the cow's teat. 
It is another object of the present invention to provide a teat knife in 
the form of a rod having a needle's eye in the distal end with at least 
one edge sharpened for removal of obstructions upon insertion and rotation 
within the milk duct of the teat. 
It is another object of the present invention to provide a teat knife of 
simplified construction such that it can be made from stainless steel or 
other suitable materials that can be easily and simply cleaned and 
sterilized. 
These and other and further objects and advantages of the present invention 
are obtained in a preferred embodiment by a narrow stainless steel rod 
having a knurled knob on one end for rotation thereof and having a 
flattened eye portion at the other end in which a slot is formed and at 
least one edge of the slot is sharpened to provide a knife action within 
the milk duct of the teat as the knife assembly is rotated by rotating the 
knob at the proximal end of the teat knife. The sharpened edge of the eye 
formed in the distal end of the teat knife not only cuts the obstruction 
loose, but it also helps to capture the obstruction and to permit freeing 
it from the wall of the milk duct as well as removal of the severed tissue 
.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring now to FIG. 1, there is shown a teat knife 10 in accordance with 
the present invention. The body of the teat knife is formed by an 
elongated narrow cylindrical rod 12 which has an enlarged knurled knob 14 
at one end and an enlarged flattened eye area 16 at the other end. The 
instrument is formed as an integral unitary piece and is designed to be 
operated by the fingers of one hand manipulating the knurled knob 14 in a 
rotary fashion after inserting the rod 12 inside the milk duct of the teat 
of the cow. The farmer, in normal use, will insert the knife in the teat 
while holding the teat in the other hand and rotate the eye knife portion 
so as to remove the obstruction limiting the flow of milk through the milk 
duct. 
Referring to FIG. 2 there is shown an enlarged cross section of the eye 
portion 16 of the knife 10. As may be seen, the eye portion 16 is enlarged 
in width compared to the diameter of the rod 12, to the dimension shown 
relatively in FIG. 2. The width of the eye portion 16 is approximately 
fifty percent greater than the diameter of the rod portion 12. The eye 
portion 16 is somewhat flattened and has two side members 18 and 20 
disposed on either side of a slot 19. The outer surfaces of 18 and 20 are 
arcuate forming a portion of the circumference of a circle having a 
diameter approximately equal to the width of eye portion 16. The two side 
members 18 and 20, in cross section, may be said to form approximate 
chordal segments of a circle drawn about the edges of the eye portion 16. 
As can be seen in FIG. 2, the side member 18 has a rounded edge 30 and a 
cutting edge 32, while the side member 20 has a rounded edge 30 on each 
edge thereof. The rounded edges are contoured so as to facilitate rotation 
of the knife 10 within the milk duct and the increased width of eye 
portion 16 with the rounded edges tends to guide or position the cutter in 
operative position with the inside surface of the milk duct. As also can 
be seen in FIG. 2, the cutting edge 32 is formed by sharpening the edge of 
the side member 18 from the inside out to form a cutter edge at the 
circumference of the eye portion 16. A rounded tip 36 is shown on the 
distal end of the eye to facilitate entrance of the knife into the milk 
duct and to help guide the tool into proper position within the milk duct. 
During use, the enlarged cross section of the eye portion 16 and the 
rounded circumference of portions 18 and 20 serve to extend and support 
the duct so that an obstruction can be "captured" in the slot 19 of eye 
portion 16 and cut loose by rotation of cutter edge 32 for removal from 
the duct. The relative small size and rounded outer surfaces permit the 
tool to be used while inflicting minimum injury to the milk duct and teat 
of the cow. 
Referring now to FIG. 3, there is shown another embodiment of the present 
invention in which the lower edge of each side member 18' and 20' is 
sharpened 32' in the manner shown in FIG. 2 to provide two sharpened 
cutters so that the tool will cut whether it is rotated in the clockwise 
or counter-clockwise direction. 
In use, the tool is inserted into the obstructed milk duct of the teat with 
one hand while the obstruction is located with the other hand. The knife 
is positioned so that the eye 16 contacts or surrounds the obstruction. By 
rotating the knife as shown in FIG. 2 in the clockwise direction, the 
cutter edge 32 can be brought into contact with the obstruction and the 
obstruction cut or scraped from the lining of the milk duct. In the 
configuration shown in FIG. 3, the tool can be rotated in either the 
clockwise or counter-clockwise direction, whichever is more appropriate to 
sever and remove the obstruction from the lining of the milk duct of the 
teat. 
For certain types of obstructions such as small "floating cysts", the 
distal end surface 21 of slot 19 of eye portion 16 has a width sufficient 
to capture the floating cyst in the eye and remove it from the milk duct 
by withdrawal of the knife from the teat. This distal surface 21 is 
disposed perpendicularly to the axis of rod 12. 
It will thus be seen that I have provided a very simple tool easily and 
cheaply manufactured that can be effectively used to remove obstructions 
from the milk duct of the teat of a cow without causing serious injury to 
the cow. The tool being made of stainless steel is easily cleaned and 
sterilized. 
While this invention has been explained with reference to the structure 
disclosed herein, it is not confined to the details set forth and this 
application is intended to cover any modifications and changes as may come 
within the scope of the following claims: