Animal husbandry – Milkers – Teat compressor or cup
Reexamination Certificate
1999-05-04
2001-01-23
Carone, Michael J. (Department: 3643)
Animal husbandry
Milkers
Teat compressor or cup
Reexamination Certificate
active
06176200
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention refers to a teatcup liner intended for being mounted in a teatcup shell, comprising
a tubular head portion, which forms a passage arranged to receive a teat and extending between a first and a second axial end of the tubular head portion, and which comprises an annular lip, extending radially inwardly from the tubular head portion in the mounted as well as the non-mounted state of the teatcup liner,
a tubular shaft portion, extending from the second axial end of the head portion, and
a member arranged to provide a radially outwardly directed pretension in the lip in the mounted as well as the non-mounted state of the teatcup liner. Moreover, the invention refers to a method of manufacturing a teatcup liner.
2.Description of the Prior Art
U.S. Pat. No. 4,324,201 discloses a type of teatcup liner which comprises a tubular upper part forming a passage for receiving a teat. An annular lip extends radially inwardly from the tubular upper part and defines a circular aperture for the teat. A tubular shaft portion extends downwardly from the upper part to abut the teat being introduced therein. This type of teatcup liner is intended to be mounted in a teatcup shell by simply being introduced therein. In connection with the mounting, no real deformation of the teatcup liner takes place. When the rubber material of such teatcup liners ages, the lip to enclose the teat will be weakened. This means that the teatcup liner already at an initial stage, i.e. when it is applied to the teat, will crawl upwardly on the teat, which may result in a hindering influence to the milk flow. Furthermore, a weakened lip means that the slip frequency, i.e. the inlet suction of air between the teatcup liner and the teat, increases. This type of teatcup liner is also disclosed in U.S. Pat. No. 4,745,881.
U.S. Pat. No. 4,116,165 discloses another type of teatcup liner achieving its effective shape first when it is mounted in a teatcup shell. In its most basic embodiment, this type of teatcup liner merely is comprised by a hose portion. The teatcup liner disclosed comprises in a mounted state a tubular upper part forming a passage for receiving a teat. An annular lip extends radially inwardly from the tubular upper part and defines a circular aperture for the teat. A tubular shaft portion extends downwardly from the upper part to abut the teat. Furthermore, there is a ring, which is arranged to provide a radially outwardly expansion of the upper part and a radially outwardly pretensioning of the lip. This is obtained by the ring, consisting of a separate part, being introduced into the passage in such a manner that the upper part is expanded. Consequently, the pretensioning ring will be located in the passage. Since the separate ring has to be mounted in the teatcup liner when this has been mounted in a teatcup shell, the exchange of the teatcup liner is complicated. Furthermore, the ring provided in the milk passage results in an accumulation of dirt, rest milk, bacteria etc in its area. The gaps and pockets which are formed in the area of the ring are very difficult to keep clean without demounting the whole teatcup and by the cleaning methods normally used for cleaning the milking equipment. U.S. Pat. No. 2,120,556 discloses a somewhat more developed variant of such a hose-like teatcup liner, which has been provided with an expanded part in the upper end.
U.S. Pat. No. 3,973,521 discloses a further type of teatcup liner having a prolongation extending upwardly from the lip and being intended to be folded downwardly over a teatcup shell when the teatcup liner is mounted therein. In such a manner the teatcup liner is fixed in the teatcup shell and simultaneously seals off a pulsating chamber between the shell and the teatcup liner. Furthermore, between the shell and the teatcup liner, a resilient ring member is provided. The ring member, which consists of a separate part which is attached first when the teatcup liner is mounted in the shell, functions to position the teatcup liner in the teatcup shell and to provide a radially outwardly tension of the lip. However, the embodiment disclosed is very complicated and involves a difficult and time-consuming mounting, especially at the conditions prevailing in a stall.
U.S. Pat. No. 2,282,159 discloses a teatcup liner having a head portion and a shaft portion to be introduced into a teatcup shell. The head portion has a first and a second axial end and an annular lip extending radially inwardly from the head portion. According to a first embodiment, a split extension ring is provided in a passage of the head portion on top of the lip. According to a second embodiment, the ring is completely embedded in the rubber material of the head portion. However, at least in this latter case it does not seem possible to obtain a radially outwardly directed pretension of the lip embedded in the rubber material.
This is also the case for the teatcup liner disclosed in GB-A-491 694. This document discloses a similar teatcup liner having a reinforcing ring completely embedded in a thickened outer head portion of the teatcup liner.
SUMMARY OF THE INVENTION
The object of the present invention is to remedy the problems mentioned above and in particular to provide a teatcup liner which easily may be mounted and which has an improved elasticity of the lip. Further object is to provide a method of manufacturing such a teatcup liner.
The first of these objects is obtained by the teatcup liner initially mentioned and characterized in that said pretensioning member is located outside said passage. Such a teatcup liner may in an easy way be mounted in a teatcup shell by merely being introduced therein and pulled into a proper position. No further tools or expanding devices are necessary. Furthermore, such a teatcup liner has a long lifetime with respect to the lip subjected to deformation, since it due to the pretensioning force is more resistant to such deformations. Investigations performed by the applicant have shown that a pretensioned lip results in a higher milk flow in a shorter time period, i.e. a faster and thus more effective milking. The teatcup liner having a pretensioned lip according to the invention seals better against the teat and thus involves less air leakage. Thanks to the provision of the pretensioning member outside the passage through which the milk flows, as proposed by the invention, the teatcup liner is in addition easier to keep clean and accumulation of dirt, rest milk, bacteria and the like in the inner space of the teatcup liner, and in the milk flow passage, may be prevented.
According to an embodiment of the invention, the pretensioning member is located in essentially the same axial position as the lip. In such a manner, essentially the whole expanding force of the pretensioning member will act on the lip.
According to a further embodiment of the invention, the head portion in its second end forms an annular recess which is shaped in such a manner that it, in the mounted state of the teatcup liner, engages the teatcup shell in which the teatcup liner is mounted.
According to a further embodiment of the invention, the pretensioning member is provided in a recess of the first end of the head portion. Thereby, the recess may be open at least in a direction away from the shaft portion. Advantageously, the pretensioning member, by means of attachment means, is fixedly connected to the teatcup liner. The attachment means may comprise portions of the pretensioning member and the teatcup liner which form a melted connection, or hooks projecting from the pretensioning member and arranged to engage the head portion.
According to another embodiment of the invention, the pretensioning member is enclosed in a cavity provided in the first end of the head portion and formed by a collar-like projection foldable around the pretensioning member. Thereby, the collar-like projection may in its outer end comprise an annular thickened portion. In such a manner, the downwardly folded projection will be t
Alfa Laval Agri AB
Carone Michael J.
Gellner Jeffrey L.
Hovey Williams Timmons & Collins
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