Patent Description:
Short milk tubes are known, for example, from <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

In milk harvesting facilities, dairy animals are arranged in stalls and milker units are attached to the animals' teats to harvest milk. The milker units include a teat cup for each teat, a teat cup liner disposed inside each teat cup, a short milk tube joined to or formed integrally with each teat cup liner, and a milking claw and bowl assembly for collecting milk from all of the short milk tubes in the milker unit for passage to a central dairy milk pipeline.

The dairy environment is harsh and milker units are subject to constant use, abuse from handling by dairy operators, and impacts from animals. Consequently, dairy milker unit components must be robust and securely connected to one another to provide reliable service. Short milk tubes, in particular, must bend between a milking position and a standby position during which the short milk tube must also carry the weight of the teat cup and liner.

When being attached to an animal or shortly after milking, the teat cup and liner hang down and the short milk tube is bent or kinked to cut off a constant vacuum being applied in the milker unit from reaching the open-ended teat cup liner and undesirably drawing air into the central dairy milk line. Typically, the bending of the short milk tube occurs at the end of an inlet to the milking claw. Some prior short milk tubes incorporated radial grooves in the teat cup liner milk tube to optimize flexibility and achieve better air-flow reduction during the attachment process, but the radial grooves can result in reduced durability in that area of the milk tube.

Also, the milk claw inlet is made of stainless steel and is tapered to a relatively aggressive edge that engages the bent portion of the short milk tube. With the weight of the teat cup and the teat cup liner hanging on the short milk tube, the milking claw inlet can cause excessive short milk tube wear.

The connection between the short milk tube and the milk claw inlet is typically a friction fit with the short milk tube pushed onto an outer surface of the inlet. The short milk tube also develops a strong adherence to the milk claw inlet during use, so operators typically install the short milk tubes only part way onto the inlet of the milking claw to make it easier to remove the short milk tubes when they need to be changed.

Thus, there is a need for a durable short milk tube that is easy to attach to the milk claw nipple and limits air flow into the central dairy milk lines while the teat cup is not in use and is being attached to the dairy animal.

The present invention provides a short milk tube having a reliable seal over a milk claw inlet when a milker unit is not being used and when its corresponding teat cup and liner are being attached to an animal teat. A milker unit short milk tube in accordance with the present invention includes the features of claim <NUM>. The position and release device is joined to and extending away from the downstream milk claw connection end to ensure that the short milk tube components are located with precision or to aid in removal. The short milk tube may be separate from a teat cup liner or formed integrally with the liner.

The short milk tube may also include a flexible portion for reliable bending to seal the short milk tube, and a reinforced portion to improve durability. Controlled and reliable short milk tube flexing can be provided by a grooved portion on the short milk tube positioned to conform to a beveled portion of a milking claw inlet, thereby maximizing air flow reduction when not in use and also during the process of attaching the milker unit to the cow. The grooved portion is prone to excessive liner wear, so a reinforced portion slightly upstream from the grooved portion is also provided to engage an end portion of the milk claw inlet. These critical features require relatively precise positioning of the short milk tube attachment to the milk claw inlet to function properly, so the position and release device is used for installing the milk tube consistently and accurately.

A reliable position and release device on the end of the short milk tube in accordance with the present invention ensures that the flexing and reinforced portions are located accurately relative to the end of the milking claw inlet. Incompletely positioning the short milk tube on the pointed end of the milk claw inlet could cause the flexing portion not to align properly and result in a failure to properly seal the liner from vacuum or cause the flexible portion to engage the aggressive end portion of the milk claw inlet.

Further, easier removal of the short milk tube from the milking claw inlet is achieved by first pushing the milk tube further onto the inlet to compress the position and release device, and then pulling the short milk tube from the inlet. The initial pushing to compress the position and release device significantly reduces friction when the short milk tube is put under tension for removal. The position and release device preferably includes protruding positioning prongs to touch the milking claw top surface and act as spacers to guide installation to the optimum position on the milking claw nipple during installation. When it is necessary to remove the short milk tube, the positioning prongs are compressed to break at least some of the adherence of the short milk tube to the milker unit inlet to make it easier to pull off the short milk tube.

The reinforced portion of the short milk tube can be disposed on the outer wall surface opposite the interior milking claw inlet sealing surface, and be a portion of increased wall thickness or a different and more durable material than the rest of the short milk tube. The controlled flexible portion is preferably an area of reduced wall thickness and can include a plurality of annular grooves, and a plurality of ribs disposed in the grooves. The short milk tube can be integral with or separate from the teat cup liner. The claw inlet sealing surface can be part of the tube inner wall surface or be a separate device or material mounted inside the tube.

Further details and advantages of the present invention are described below.

Illustrated generally in <FIG> is a traditional milker unit <NUM> having a teat cup <NUM>, a teat cup liner <NUM> disposed in the teat cup <NUM>, a short milk tube <NUM> joined to or formed integrally with the teat cup liner <NUM>, a milking claw <NUM>, and milk bowl <NUM> at its downstream end. There is one teat cup <NUM>, liner <NUM>, and short milk tube <NUM> for each teat of the dairy animal. The milking claw <NUM> and milk bowl <NUM> collect milk from all short milk tubes <NUM>. (The milker unit illustrated in <FIG> is depicted for background and does not illustrate the short milk tube invention described below).

The objective of the milker unit <NUM> is to draw milk away from the dairy animal teats, out of a milk bowl outlet <NUM>, and into the central dairy milk lines (not illustrated), reduce the amount of milk flowing back toward the teat, and reduce the amount of air drawn into the central dairy milk line when vacuum is being applied.

During milking, a dairy animal teat is inserted through an upper orifice of the teat cup liner <NUM>. Just before and during milking, a constant vacuum is applied inside the milker unit <NUM> to attach the liner <NUM> and teat cup <NUM> to the teat and then draw milk through the liner <NUM>, the short milk tube <NUM>, the milking claw <NUM> and the bowl <NUM>, and out of the milk bowl outlet <NUM>. The weight of the milker unit <NUM> is supported by the teats because of the constant vacuum being applied inside the milker unit <NUM>.

The teat cup <NUM> (sometimes referred to in the art as a "shell") is a relatively rigid cup typically made of stainless steel or other suitable material. The teat cup liner <NUM> is disposed inside the teat cup <NUM>, and a pulsation chamber is defined in the space between the teat cup <NUM> and the liner <NUM>. A pulsating vacuum is applied through a short pulse tube <NUM> that extends between a short pulse nipple <NUM> and a short pulsation connection <NUM> on the milking claw <NUM>. A long pulsation hose (not illustrated) connects to a long pulsation hose nipple <NUM> on the milking claw <NUM>. The pulsation acting on the pulsation chamber moves the liner <NUM> in and out of contact with the animal teat to milk the animal. A hanger <NUM> is also provided on the milking claw <NUM> to support the milker unit <NUM> from a milker unit detacher mechanism (not illustrated) when not milking.

The short milk tube <NUM> of the present invention includes a wall <NUM> having an outer wall surface <NUM> and an inner wall surface <NUM> defining a milk passage <NUM>. The milk passage <NUM> has as an upstream direction toward the liner <NUM> and a downstream direction toward the milking claw <NUM>. The short milk tube further includes; a downstream milk claw connection end <NUM> and a position and release device <NUM> joined to and extending away from the downstream milk claw connection end <NUM>. Preferably, the short milk tube <NUM> also includes a controlled flexible portion <NUM> disposed in the upstream direction from the position and release device <NUM>, a reinforced portion <NUM> disposed in the upstream direction from the controlled flexible portion <NUM>, and an interior milking claw inlet sealing surface <NUM> disposed on the inner wall surface <NUM>.

When the milker unit <NUM> is attached to an animal in a "milking position" (<FIG>), the milker unit <NUM> is essentially a closed system and there is relatively little stress on the short milk tube. When the milker unit <NUM> is released from an animal, the teat cup <NUM> and the liner <NUM> drop downward and the short milk tube <NUM> bends over into a "standby position" (<FIG>). The bending of the short milk tube <NUM> essentially kinks the short milk tube <NUM> against the milking claw inlet <NUM> to prevent air from entering the now open end of the teat cup liner <NUM>. The milking claw inlet <NUM> is made of stainless steel and is tapered, so a relatively aggressive edge engages the inner wall surface of the bent portion of the short milk tube <NUM>. The short milk tube <NUM> of the present invention resists wear by including the reinforced portion <NUM> adjacent to and upstream from the milking claw inlet <NUM> so that it engages the inlet <NUM> when the short milk tube <NUM> is properly positioned.

Further, when the constant vacuum is resumed just prior to milking and before the teat cup <NUM> and liner <NUM> are attached to the animal, the kink in the short milk tube <NUM> permits the interior milking claw inlet sealing surface <NUM> to seal off the constant vacuum from reaching the open-ended teat cup liner <NUM> and undesirably drawing air into the central dairy milk line.

The controlled flexible portion <NUM> is disposed adjacent to and downstream from the reinforced portion <NUM> to enhance and control the direction and degree of bending to optimize contact between the interior milking claw inlet sealing surface <NUM> and the milking claw inlet <NUM>. The controlled flexible portion <NUM> preferably includes at least a portion of an annular groove <NUM> (<FIG>) extending at least part way around the wall of the short milk tube <NUM>, and more preferably includes a plurality of annular grooves <NUM> disposed in the upstream direction from the milking claw contact prongs <NUM>. Also preferably, the annular grooves <NUM> each include a number of ribs <NUM> to further control the degree and direction of bending. The ribs <NUM> are illustrated extending on a longitudinal direction relative to the short milk tube <NUM>, but other orientations can be used as well. The controlled flexible portion <NUM> can include other wall thickness, groove, rib, and other shapes to control the degree and direction of bending.

The reinforced portion <NUM> is illustrated as an area of increased wall thickness and it is preferred that the wall thickness taper in both the upstream direction and the downstream direction, although other shapes can be used and the thickened portion can be replaced or enhanced with other materials or shapes.

The interior milking claw inlet sealing surface <NUM> can be part of the inner wall surface <NUM> or a separate part or a different material joined to the inner wall surface <NUM>. It is also possible that one of the teat cups will drop off from one of the teats before the other teat cups. With a constant vacuum still being applied, the liner <NUM> will be sealed off by the weight of the teat cup hanging down and kinking the short milk tube <NUM>, so that the amount of air drawn into through the milker unit <NUM> is minimized.

With this arrangement of the reinforced portion <NUM>, the sealing surface <NUM> and the controlled flexible portion <NUM>, the short milk tube <NUM> of the present invention performs the sealing function efficiently without excessive wear to the inside of the short milk tube <NUM>.

In the illustrated embodiments, the reinforced portion <NUM>, the controlled flexible portion <NUM>, and the sealing surface <NUM> are symmetrical about the longitudinal axis of the short milk tube <NUM>, but asymmetrical features can also be used to provide controlled bending in only one direction, for example.

The short milk tube <NUM> can be made of rubber, silicone, or other flexible material to provide the necessary bending and flexibility to move between the milking position (<FIG>) and the resting/non-milking position (<FIG>). The flexibility at the controlled flexible portion <NUM> provides these benefits, but to operate properly, it must be positioned accurately on the milking claw inlet <NUM>. For example, if the short milk tube <NUM> is not pushed far enough onto the inlet <NUM>, the reinforced portion <NUM> will be above and spaced apart from the inlet <NUM> and serve no purpose. On the other hand, if the short milk tube <NUM> is pushed too far onto the inlet <NUM>, the reinforced portion <NUM> will also miss the inlet <NUM> end, and the controlled flexible portion <NUM> will be too close to the milking claw <NUM> and be constrained by the milking claw inlet <NUM>.

The present invention, therefore, further includes the short milk tube position and release device <NUM> that provides a visual indication when the short milk tube <NUM> has been pushed onto the milking claw inlet <NUM> to the proper extent so that the reinforced portion <NUM>, the interior milking claw inlet sealing surface <NUM>, and the controlled flexible portion <NUM> are properly positioned relative to the inlet <NUM>. Further, when any or all of the controlled flexible portion <NUM>, the reinforced portion <NUM>, or the sealing surface <NUM> are asymmetrical as described above, the rotational orientation of the short milk tube <NUM> would be important, and the position and release device <NUM> can be used to ensure proper rotational orientation relative to the asymmetrical features.

The position and release device <NUM> preferably includes at least one milking claw contact prong <NUM>, and more preferably includes a number of spaced apart milking claw contact prongs <NUM> extending away from the end of the short milk tube <NUM> to touch a top face <NUM> of the milking claw <NUM> and provide a readily visible indication that the short milk tube <NUM> has been positioned onto the milking claw inlet <NUM> when they contact a top surface <NUM> of the milking claw <NUM> that is adjacent to the milking claw inlet <NUM>. The milking claw contact prongs <NUM> also provide physical resistance to ensure that the short milk tube <NUM> has not been pushed too far down the inlet <NUM>. Nonetheless, the milking claw contact prongs <NUM> are still capable of being compressed for removing the short milk tube <NUM>, as discussed below.

The milking claw contact prongs <NUM> are depicted as being uniformly sized and spaced, but different quantities, materials, sizes, spacings, and even colors are also possible, especially when they are used to ensure proper rotational orientation, as described above. It is also possible to include one or more alignment markings on the milking claw top face <NUM> or other appropriate location for alignment with a contact prong <NUM> to achieve a predetermined rotational alignment of the short milk tube <NUM>. When multiple milking claw contact prongs <NUM> are included, it may not be necessary that all of them touch the top face of the milking claw <NUM> to indicate proper positioning of the short milk tube <NUM>.

Further, the milking claw contact prongs <NUM> assist in removing the short milk tube <NUM> when they must be replaced due to normal wear and tear or other damage. Assistance is useful because the short milk tube <NUM> has an inlet contact portion <NUM> (upstream from the position and release device <NUM> and at least partially downstream from the controlled flexible portion <NUM>) that oftentimes develops a tenacious adherence to the milking claw inlet <NUM> during normal use. Simply tugging on the short milk tube <NUM> to separate the two can require considerable force and is actually counterproductive because the adherence to the milking claw inlet <NUM> causes the short milk tube <NUM> material to draw down and stretch, which applies an additional normal force on the interface between the inlet contact portion <NUM> of the short milk tube <NUM> and the milking claw inlet <NUM>. As a result, some dairy operators only install the short milk tube <NUM> part way onto the milking claw inlet <NUM> to make removing short milk tubes somewhat easier. Such a partial installation of the present invention results in the above-described elements being improperly aligned on the milking claw inlet <NUM>, and thus, the benefits of the present invention will not be fully realized.

To break the adherence and release the short milk tube <NUM> of the present invention, the operator actually pushes the short milk tube <NUM> toward the milking claw <NUM> to compress (<FIG>) or flare (<FIG>) (or both compress and flare) the milking claw contact prongs <NUM> against the milking claw <NUM> top face <NUM>. The compressed or flared milking claw contact prongs <NUM> are a visual indication that the short milk tube <NUM> can then be more easily pulled from the milking claw inlet <NUM> because the adherence of the inlet contact portion <NUM> to the milking claw inlet <NUM> has been at least partially overcome. The adherence is at least partially overcome because the compressed (<FIG>) or flared (<FIG>) milking claw prongs <NUM> also bend or compress the adjacent inlet contact portion <NUM> of the short milk tube <NUM> away from the inlet <NUM> and thereby at least partially break any adherence between the short milk tube <NUM> and the milk claw inlet <NUM> as seen in <FIG>. Thus, the milking claw contact prongs <NUM> serve to properly position the short milk tube <NUM> when being installed and to aid in releasing the short milk tube <NUM> when replacement is required.

The milking claw contact prongs <NUM> can be any desired shape or material, but it is preferred to shape them as integrally formed truncated pyramids that are substantially rectangular in cross-section as seen if <FIG>, for example, so that they provide progressively more resistance as they are pushed against the milking claw <NUM>. Other shapes such as cones, truncated cones, pyramids, cubes, cylinders, and so on, can be used as well. Using such shapes to touch the milk claw top face <NUM> provides a tactile as well as visual indicator of proper installation of the short milk tube <NUM>.

Installing the short milk tube using the position and release device <NUM> includes the steps of pushing the short milk tube <NUM> onto the milking claw inlet <NUM> until the position and release device <NUM> contacts the upper surface <NUM> of the milking claw <NUM> to ensure that the controlled flexible portion <NUM>, reinforced portion <NUM>, and the sealing surface <NUM> are located accurately relative to the end of the milking claw inlet <NUM>. Inaccurately positioning the short milk tube <NUM> on the milking claw inlet <NUM> could cause the controlled flexible portion <NUM>, the reinforced portion <NUM>, and the sealing surface <NUM> not to align with the end of the inlet <NUM>. Easier removal of the short milk tube <NUM> is achieved by a method of first pushing the short milk tube <NUM> further onto the inlet <NUM>, and compressing the position and release device <NUM> (contact prongs <NUM> in the illustrated embodiment) and compressing and bending the adjacent inlet contact portion <NUM> outwardly from the inlet <NUM> to thereby at least partially break the bond that may have formed between the inlet contact portion <NUM> and inlet <NUM>. This then allows significantly less friction when the step of putting the short milk tube <NUM> under tension (pulling) for removal. is performed. Therefore, protruding positioning prongs <NUM> act as spacers to guide installation to the optimum extent on the inlet <NUM> during installation, yet can be easily compressed during the removal procedure to indicate that the bond at the mating interface has been broken before the short milk tube <NUM> is pulled off.

In <FIG> through <NUM>, a second embodiment of the present invention is illustrated having a teat cup liner <NUM>, a short milk tube <NUM>, and a milk claw connection end <NUM> with a position and release device <NUM> as part of the downstream milk claw connection end <NUM> of the short milk tube <NUM>. This embodiment of the position and release device is designated by the reference numeral <NUM> to distinguish it from the embodiment described above with reference numeral <NUM>. As in the embodiment described above, the second embodiment of the milk claw connection end <NUM> also preferably includes the controlled flexible portion <NUM>, a reinforced portion <NUM>, and an interior milk claw inlet sealing surface <NUM>.

The position and release device <NUM> of this second embodiment includes the contact prongs <NUM> to touch and be compressed against a top face <NUM> of the milking claw <NUM> (as in <FIG>, for example). In the illustrated embodiment of the position and release device <NUM>, the contact prongs <NUM> are spaced apart and form pairs of prongs <NUM>. A web <NUM> is provided extending away from the end of the short milk tube <NUM> and the web <NUM> may touch or be spaced apart from the top face <NUM> of the milking claw <NUM> when in use.

In this embodiment, the web <NUM> is preferably attached to and disposed between pairs of the prongs <NUM> to enable easier release from a forming mold. The web <NUM> is compressible and is preferably formed of the same material as the prongs <NUM>, so that the web <NUM> is compressible with the prongs <NUM>. Nonetheless, variations in thicknesses and geometry can be used to control the location and degree of compression, if desired. The prongs <NUM> and the webs <NUM> are preferably uncompressed when the milking operations are being performed. During removal of the short milk tube <NUM>, the prongs <NUM> and the webs <NUM> of the position and release device <NUM> are compressed against the milking claw <NUM> top face <NUM> to at least partially bend the inner inlet contact portion <NUM> away from the milking claw to aid in releasing the short milk tube <NUM>, as described above. The addition of the web <NUM> can add a degree of resistance to being compressed, but otherwise, the position and release device <NUM> operates as described above in relation to the embodiment labeled <NUM>.

The web <NUM> is depicted as a continuous inner ring in <FIG>, but the web <NUM> could be segmented and may only span between adjacent pairs of the prongs <NUM> or be present between fewer than all of the pairs of the prongs <NUM>. Further, the web <NUM> is depicted as being formed integrally with the other elements of the position and release device <NUM>, but all or a portion of the web <NUM> could be added to the position and release device <NUM> to provide reinforcement for the prongs <NUM>, for example.

Claim 1:
A milker unit short milk tube (<NUM>) adapted to be positioned onto an outer surface of milking claw inlet (<NUM>), the milker unit short milk tube (<NUM>) comprising:
an outer wall surface (<NUM>);
an inner wall surface (<NUM>) defining a milk passage (<NUM>) having an upstream direction and a downstream direction; and
a downstream milk claw connection end (<NUM>) including a position and release device (<NUM>), characterized in that
the position and release device (<NUM>) is compressible in the downstream direction to outwardly bend an adjacent inlet contact portion (<NUM>) of the short milk tube (<NUM>) away from the milking claw inlet (<NUM>) to aid in releasing the milker unit short milk tube (<NUM>) from the milking claw inlet (<NUM>).