Abstract:
A valve assembly for use in an animal feeding teat and an animal feeding teat in combination with the above valve assembly. The valve assembly includes a piston shaft with a piston head, a valve head attached to the piston shaft at the end of the shaft opposite the piston head, and a biasing structure co-operable with the piston head, so that in use in an animal feeding teat the valve head is seated to cover a first aperture in the teat and pressure on the piston head against the biasing structure will unseat the valve head and open the aperture.

Description:
FIELD OF THE INVENTION 
     This invention relates to a valve assembly. 
     The valve assembly of an embodiment of the present invention is particularly adapted to be used within an animal feeding teat. However, other uses of the valve assembly of the present invention are also contemplated. 
     BACKGROUND TO THE INVENTION 
     Traditionally animal feeding teats operate by the feeding animal sucking on the teat to start the flow of liquid. The disadvantage of such teat assembly is that if the opening in the nipple of the teat becomes ripped or broken, the liquid will spill out of the teat even when the animal is not sucking on the teat. Other traditional teats also have the disadvantage that once liquid is flowing through the teat, it will only stop once all the liquid is emptied from the receptacle the teat is attached to. This can cause the animal feeding from the teat to choke on the liquid, or allow spillage and waste of liquid. 
     Another disadvantage of many traditional feeding teat assemblies is that if the animal pulls the teat to one side, liquid will not flow through the teat. Such teats need to be kept substantially in line with the liquid outlet to operate. 
     Some teats known in the art contain a valve assembly which operates under the force of gravity to close the valve once it has been opened. The disadvantage of such a teat valve assembly is that it will only operate effectively if the teat is substantially vertical to the ground. 
     One such invention is described in NZ 110 435. This patent discloses a tubular nozzle that is attached to a container and fitted with an internal rubber covered valve. The free peripheral edge of the nozzle is formed into an upturned flange with curled portion of a flexible teat fitting over and between the flange and the perpendicular wall of the nozzle, with a portion of the teat lying flat against the wall to make an airtight seal. The valve is gravity operated and the teat must be hanging vertically or near vertically for the valve to close. 
     The invention described in NZ 102 401 is a tubular nozzle fitted to the lower end of a food containing vessel with a resilient teat attached to its end. Inside the nozzle is a valve which consists of a metallic ball-head with a depending stem to the lower end of which is fitted a rubber knob. When an animal sucks the teat, the valve is displaced upwardly and liquid can flow through the teat. When the animal releases the teat, the valve is closed by gravity and no liquid can flow. This construction is also limited to use where the teat hangs vertically or near vertically. 
     The invention described in NZ 39 125 comprises a containing-vessel for a liquid with a concave or sloping bottom, an angular outlet with a rubber teat at the end thereof for an animal to suck. Within the vessel is a float valve, which may be closed against its seat by the operation of a float or by hand. 
     In NZ 35 868, there is described a means employed for feeding calves and the like with liquid food. According to this invention, a reservoir for the liquid has a false bottom in which is a valve adapted to close by gravity. A sliding tray beneath the bottom is provided with a float upon one end of a pivoted lever, the other end of which engages a downwardly projecting stem of the valve. The liquid in the tray is thus kept at a predetermined level by the rise and fall of the float. A branch pipe from the tray is connected by a rubber tube or similar flexible connector with a running-pipe supplying the liquid to the animals. Wastage is prevented by locating the orifices from the pipe to the teats on a level with, or slightly higher than, the surface of the liquid in the tray. 
     The invention in U.S. Pat. No. 5,638,769 discloses a teat comprising a hollow body made of a resilient material. The body has an inlet and an outlet end. The outlet end includes at least one slit through the wall of the body. This slit(s) does not extend into that area of the wall of the body which forms the extremity of the outer end. Engaged with the inlet end is a valve biased by a spring. As an animal suckles on the teat a pressure differential forms within. This suction causes the valve to open allowing liquid to fill the teat. When the suction is removed the valve closes. The closed valve prevents any backflow when the teat is squeezed. 
     GB 2 267 549 discloses a teat valve comprising an apertured closure member which co-operates with a tubular seat and an elastic sleeve which houses both the member and the seat and urges them into sealing engagement. When the sleeve is stretched, the valve opens allowing passage of liquids/solubles and gases, and when released returns to its original position, thus closing the valve. 
     It is an object of the present invention to provide a valve assembly adapted for use in an animal feeding teat which will go some way towards overcoming the above-mentioned disadvantages or which will at least provide the public with a useful choice. 
     DISCLOSURE OF INVENTION 
     This invention can be said broadly to consist in a valve assembly adapted for use in an animal feeding teat, said valve assembly comprising 
     a piston shaft with a piston head, 
     a valve head attached to the piston shaft at the end of the shaft opposite the piston head, and 
     biasing means co-operable with said piston head, 
     so that in use in an animal feeding teat said valve head is seated to cover a first aperture in said teat and pressure applied by said animal on said teat causes said teat to act directly on said piston head to move said valve assembly against said biasing means to unseat said valve head and open said aperture. 
     Preferably the piston head is bulbous in shape. 
     Preferably the piston head is tapered at the end remote from the valve head. 
     Preferably the biasing means is a spring. 
     Preferably the spring is a coil spring. 
     Most preferably the spring is comprised of stainless steel. 
     Preferably the spring is coiled around the piston shaft. 
     Preferably the piston head contains at least one recess. 
     Preferably the piston shaft, piston head and valve head are formed as one unit. Preferably that unit is comprised of nylon. 
     The invention can also be said broadly to consist in a combination of an animal feeding teat with the valve assembly described above. 
     Preferably the teat comprises: 
     an outer casing, 
     a first aperture at one end of the casing connectable to a source of fluid, through which the valve head of the valve assembly protrudes, and 
     at least one second aperture in the outer casing through which liquid can flow to feed the animal, 
     whereby when pressure is applied onto the piston head, the valve head is unseated from the first aperture to allow fluid to flow through the first aperture into the outer casing and subsequently out of the second aperture and closes when the pressure is removed from said piston head. 
     In one alternative the pressure is applied by an animal&#39;s mouth or teeth through said outer casing. In another alternative the pressure is applied by the atmosphere on the outer casing when an animal sucks on the teat thereby creating a partial vacuum within the teat. 
     Preferably the second aperture is located at the opposite end of the casing from the end where the valve head protrudes. 
     Preferably the teat is comprised of either a durable pliant synthetic material or rubber. The rubber may be natural or synthetic. 
     The invention may further be said to broadly consist in an animal feeding teat adapted to allow incorporation of the valve assembly described above. 
     The invention may also be said broadly to consist in a valve assembly substantially as herein described with reference to the accompanying drawings. 
     The invention may also be said to broadly consist in an animal feeding teat substantially as herein described with reference to the accompanying drawings. 
     The invention may also be said broadly to consist in a combination substantially as herein described with reference to the accompanying drawings. 
     This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. 
     This invention consists in the foregoing and also envisages constructions of which the following gives examples. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     One preferred form of the present invention will now be described with reference to the accompanying drawings in which: 
     FIG. 1 shows a side elevational view of the valve assembly of the present invention. 
     FIG. 2 shows a sectional side elevation view of the valve assembly of the present invention when located inside a teat and wherein the valve head is in a closed position. 
     FIG. 3 shows a sectional side elevation view of the valve assembly of the present invention when located inside a teat and wherein the valve head is in an open position. 
     FIG. 4 is an end elevational view of the piston head viewed from the left side of FIG.  1 . 
    
    
     In the preferred form of the invention shown in FIG. 1, the valve assembly is comprised of a piston shaft  10  with a piston head  12  attached. In a preferred form of the invention the piston head  12  is bulbous, tapered to a point  13  and contains two recesses ( 38 ,  38 ) that assist in the flow of fluid through the teat. A valve head  14  is connected to the piston shaft  10 , at the opposite end of the shaft  10  from the piston head  12 . A biasing means  16  rests against the piston head  12  and is located along the piston shaft  10 . Preferably the biasing means  16  is a spring. Preferably the spring is a coil spring. Most preferably the spring is comprised of stainless steel. 
     Optionally, the piston head  12 , piston shaft  10  and valve head  14  may be moulded as one piece of material. The material is preferably nylon but any other inert rigid material would be suitable. 
     FIGS. 2 and 3 shows a preferred embodiment of the present invention wherein the valve assembly is substantially contained within an animal feeding teat  17 . The valve assembly may be fitted inside the animal feeding teat  17  by passing the valve assembly piston head  12  first through the second aperture  22  and then through the guideway  32  until it is in the position as shown in FIG.  2 . 
     The embodiment in the figures shows the teat fitted to an undefined receptacle  20 . The teat may be fitted to an animal feeding bowl, a bottle, or a hose without departing from the scope of the invention. Fittings for use in hose types are well known in the dairying industry. 
     In the embodiment shown in FIG. 2, the animal feeding teat  17  is comprised of an outer casing  18  having a head portion  24 , a shoulder portion  26  and a neck portion  28  between the head and shoulder portion. The outer casing  18  has a first aperture  22  and a second aperture  30 . The valve head  14  of the valve assembly protrudes through the first aperture  22  at one end of the outer casing  18 . 
     In the preferred embodiment shown in FIGS. 2 and 3, the animal feeding teat  17  is attached to a receptacle  20  (the boundary of which is shown by broken lines in FIGS. 2 and 3) at the end of the casing which contains the first aperture  22 . The teat  17  may be passed from the outside of the receptacle, aperture end  22  first, through a circular hole in the receptacle  20  until the edge of the hole rests in a fluid—tight fit in neck portion  28  of teat  17 . Alternatively, the teat is passed from the inside of the receptacle, aperture end  30  first through a circular hole in the receptacle until the edge of the hole rests in a fluid-tight fit in the neck portion  28  of the teat. As shown in FIGS. 2 and 3, the valve head  14  protrudes from the first aperture  22  and is located inside the receptacle  20 . 
     The head and shoulder portion  24 ,  26  are solid apart from a guideway  32  through the centre. The piston shaft  10  moves freely within the guideway  32 . The spring in conjunction with the convex valve head  14  act to keep the valve assembly in a centred position. The piston shaft is of a diameter small enough to allow fluid to flow freely through the guideway. 
     The receptacle  20  is intended to contain a liquid. The liquid may be milk or other animal feed. The liquid may comprise nutrients or medicinal supplements. In use, the valve head  14  is thus submerged in liquid within the receptacle  20 , and the outer casing  18  may protrude from the receptacle substantially horizontally or downwardly. The valve assembly of the present invention will operate effectively when positioned at any angle. 
     The valve assembly of the present invention operates as follows. An animal exerts pressure in the direction of the arrows A by biting or squeezing the teat (see FIG.  3 ). This pressure forces the piston head  12  to move in the direction of the arrow B and compresses the biasing means  16 . This in turn moves the valve head  14  away from the first aperture  22 . In FIG. 3 the valve head  14  is thus unseated from the aperture  22 . This allows the flow of liquid from the receptacle  20 , through the first aperture  22  into the teat  17 , then through the second aperture  30  and into the animal&#39;s mouth. 
     When the animal releases its bite and pressure is removed from the outer casing  18  and the piston head  12 , the biasing means  16  forces the piston head  12  to move in the direction of the arrow E (see FIG. 2) and returns the valve head  14  to seat over the first aperture  22  and thus prevent the flow of liquid through the first aperture  22  and into the teat  17 . 
     In an alternative embodiment it is the atmosphere that applies pressure in the direction of arrows A. This happens when a partial vacuum is created inside that teat as a result of an animal sucking on the teat. In the same manner as described above, the pressure forces the piston head  12  to move in the direction of the arrow B and compresses the biasing means  16 . This in turn moves the valve head  14  away from the first aperture  22 . In FIG. 3 the valve head  14  is thus unseated from the aperture  22 . This allows the flow of liquid from the receptacle  20 , through the first aperture  22  into the teat  17 , then through the second aperture  30  and into the animal&#39;s mouth. 
     When the animal stops sucking the pressure differential dissipates, effectively removing the pressure from the outer casing  18  and the piston head  12 , the biasing means  16  forces the piston head  12  to move in the direction of the arrow E (see FIG. 2) and returns the valve head  14  to seat over the first aperture  22  and thus prevent the flow of liquid through the first aperture  22  and into the teat  17 . 
     The advantages of the valve assembly when contained within an animal feeding teat as described herein are as follows. The teat valve assembly of the present invention can operate effectively at any angle. It is not restricted to use in a vertical position as it is not reliant upon gravity forces to close the valve to prevent the flow of liquid from the teat. 
     A further advantage is that the teat valve assembly operates effectively even when there is a large aperture in the nipple of the teat. In traditional animal feeding teats that do not have a shut-off valve, only small apertures can be used in the teat nipple or liquid will spill out very easily. The advantage of such a large aperture in the nipple of the teat is that foreign bodies are less likely to get caught therein and thus the teat is more hygienic. 
     The teat valve assembly of the present invention is easy for animals, such as lambs or calves, to feed from. This is because the animal need only squeeze or bite the teat to start the flow of liquid. In comparison, many traditional teats require the animal to suck the teat or squeeze up and down on the teat to obtain liquid. The teat valve assembly will also operate to open the valve and allow the flow of liquid when the teat is pulled forcefully to the side. 
     It is envisaged that the valve assembly of the present invention could be inserted into any standard or conventional teat to operate. However, the present application describes a preferential embodiment of a teat into which the valve assembly of the present invention can be inserted. 
     Even if the outer teat becomes worn or damaged, the valve assembly will continue to operate and effectively, preventing the flow of liquid unless pressure is applied to the piston head. If the outer teat becomes completely destroyed, it is envisaged that the valve assembly could be recycled and placed in a new outer casing or teat. 
     Other embodiments of the invention will be apparent to those skilled in the art.