GB2037141A - Milking apparatus - Google Patents

Abstract

Teat cup 2 is prevented from creeping up a teat by perforated rubber insert 1. The milking vacuum permeates via gap 4 and holes 7 to the teat side and aids adhesion of the teat cup thereto. The insert may be used in one- or two-chamber teat cups. <IMAGE>

Description

SPECIFICATION A milking apparatus The present invention relates to a milking apparatus.

For milking cows, two chamber milking buckets are predominantly used, and to a small extent single chamber milking buckets are also used. Two chamber milking buckets comprise a rubber teat and a sleeve. The clear width of the rubber teat is as a rule smaller than the outside diameter of the cow's teats. The rubber teat is so inserted into the sleeve that between the rubber teat and the sleeve, a closed space is provided (the pulse space) which is alter nately acted upon through an opening in the sleeve by air at atmospheric pressure or excess pressure or a vacuum. The rubber teat encloses the milk bucket interior space which is connected through a milk col lecting container with a vacuum pump and has an opening for the reception of the teat on the oppositely disposed side.This opening is in the shape of a suction head so that sealing between the rubber teat and teat takes place through a sealing lip at the suction head. The milk is sucked out of the teat through a vacuum in the milk bucket interior space when vacuum likewise acts in the pulse space (suction phase). During the phases of the alternating loading of the pulse space by air at atmospheric pressure or excess pressure, the rubber teat collapses (relief phase). The teat is relieved of the vacuum effect and the milk flow out of the teat is interrupted. In part, alternating excess pressure is also introduced into the pulse space in order to massage the teat more intensively by means of the rubber teat.Forming in the suction head of the rubber teat is an adhesive vacuum which arises in consequence of unevennesses on the teat skin and in dependence on the diameter of cow's teat and rubber teat as well as the tightness between teat base and lip of the suction head.

Single chamber milking buckets have no rubber teat as well as pulse space, but have a suction head with a sealing lip of resilient material, preferably rubber. In such milking buckets, the vacuum acts constantly on the cow's teat tip and the sucking of the milk out of the teat takes place continuously. In the suction head of single chamber milking buckets, an adhesive vacuum is also provided which analog ously to two chamber milking buckets is generated by vacuum loading of the teattip and a not completely air-tight bearing of the teat against the milk bucket wall.

Two chamber milking buckets as well as single chamber milking buckets have the disadvantage of creeping up at the cow's teats towards the end of the milking process. In conjunction with the creeping-up of the milking buckets, it comes to a closure between the gland cisterns of the udder and the teat cistern so that no milk can any longer flow on into the cow's teat cisterns. The known milking buckets are consequently not in a position of sucking the entire yieldable milk out of the udder. About 15% of the quantity of milk remains behind, which is designated as aftermilk and can be sucked off only in conjunction with manual support or by means of the milking buckets with special mechanical devices. When remaining in the udder, it hinders the milk secretion and can promote udder diseases.

At the start of milking, the adhesive friction at the contact surfaces of the rubber teat and teat skin is secured by vacuum in the milk bucket interior space and the milk pressure in the cow's teat cistern. Contact surfaces are present at the rubber teat shank and at the sealing lip. The adhesive friction is improved in the region of the sealing lip in that can adhesive vacuum is provided in the suction head, under the effect of which the teat enlarges between the sealing lip and rubber teat shank. In the region of the rubber teat shank which is in contact with the cow's teat, the adhesive friction is reiatively small and depends on the relationship of the diameter of the teat and rubber teat shank, the surface property of the rubber teat as well as the cow's teat and the milk pressure in the teat cistern.Vacuum, which acts underneath the teat, to a small degree also penetrates through skin folds between teat skin and rubberteat. This amounts to only 4 . . . 5 kPa and thus increases the adhesive friction only slightly. Analogous adhesive friction conditions exist also in the case of single chamber milking buckets, in which the teats as a rule bear against the inner wall of the milk bucket sleeve.

In the past, many trials have been undertaken to improve the adhesion of the rubber teat at the teat in order to prevent creeping-up of the milk bucket towards the end of milking. These measures mainly had the aim of attaining in the region of the teat base a better adhesion of the milk bucket through modification of the suction head. Thus, finger, groove and suction elements are used in the region of the sealing lip. Also the shape of the suction head and par ticularlythe volume of the suction head were structured differently as well as the adhesive vacuum in the suction head increased through additional vacuum supply. In the region of the rubber teat shank, one tries to improve the adhesive friction through application of protrusions in the form of knubs, ribs or the like or through roughening of the surface.

Known measures in the shank region include the use of a very narrow rubberteat, in which the diameter of the rubber teat appreciably falls below that of the teat. Only a part of the teat is received by the rubber teat. Narrow rubber teats of that kind however impair the suction capability of the milking machine appreciably. Other measures in the shank region are rubber teat wall reinforcements in the region receiving the teat in order to counteract a radial enlargement of the rubber teat shank in the suction phase and thereby a detachment of the teat from the rub berteat. Rubber teats are also known, in which the diameter is smaller in the lower shank region than in the upper (conical rubber teats).

All these measures in the shank region have the aim of impeding creeping up of the milking bucket at the teats by increasing the friction between teat skin and teat.

In the case of rubber teats, the internal walls of which are provided with ribs, apart from increasing the friction through surface structuring in the man ner of a relief, one furthermore endeavou rs that the vacuum underneath the teat spreads more inten sively between teat wall and rubber teat than in the case of smooth rubber teats. Such an effect however hardly arises since the very elastic teat skin lays itself againstthe unevennesses of the rubber teat and prevents a significant spreading of the vacuum in this region. Beyond that, rubber teats of that kind provided with ribs or knubs are hygienically very precarious since they are difficult to clean.

In the DE-OS 2 551 931, measures are described for the prevention of the dropping-off of the milk buckets for a milking process, in which the vacuum in the interior space of the milking bucket is strongly reduced in a milking phase. For this purpose, ribs are applied to the surface of the rubber teat shank. Also the rubber teat shank is structured to bulge in the part which receives the teat. The rubber teat wall is kept thinner in this region in order to enhance the bulging ofthe rubberteatshankthrough radial expansion. One likewise ascribes to the bulging that, apart from the prevention of the dropping-off of the milking bucket, it would also inhibit creeping-up of the same.The bulging and the wall weakening in the upper shank region of the rubber teat however leads to the already described measures, such a narrow rubber teats, reinforcements in the shank region and conical shank course in an opposite direction and promotes a detachment of the teat from the rubber teat towards the end of the milking process.

All described measures cannot attain the aim of preventing creeping-up of the milking buckets and bringing about a substantial emptying of the udder since these measures lead only to an improvement of the adhesion as long as the teats through the milk pressure in the udder lie against the rubber teat shank in the case of two chamber milk buckets or at the milk bucket wall in the case of single chamber milk buckets. In the end phase of the milking process, the effects of these measures become ineffective so that the problem of creeping-up of the milking buckets and the furthest possible emptying of the udder by means of suction milking machine is not solved.

The causes of the defects of the known proposal for prevention of creeping-up of the milking buckets at the teats are that in all milking processes, in which the milk is sucked off by means of vacuum and only a part of the udder or of the teat is received in the vacuum space (milking bucket), the following processes are to be observed: Towards the end of milking, the milk pressure in the udder falls off greatly, the udder volume reduced altogether and the teat constricts itself at its base.

Thereby, the connecting opening in the udder from the gland cistern to the teat cistern also narrows.

During the opening of the rubber teat in the suction phase, the flow speed of the milk flowing from the gland cistern into the teat cistern increases by reason of this narrowing, whereby vacuum arises in the region due to the flow and initiates a diaphragmlike closure of the connecting opening between gland cistern and teat cistern. This closure appears at the start of the opening of the rubber teat. In the course of the further opening of the rubber teat, vacuum arises in the teat cistern. The vacuum in the teat cistern is small at first and completely reduced in the following relief phase so that the connecting opening between gland cistern and teat cistern again opens and milk flows on in reduced extent into the teat cistern.In the course of the further emptying of the udder, the vacuum in the teat cistern increases each time during the suction phase and can attain the height of the operational vacuum in the interior space of the milking bucket. By reason of the pressure difference present between vacuum in the teat cistern and atmospheric pressure on the part of the teat protruding out of the milking bucket, the relatively small adhesive vacuum in the suction head and the small vacuum between teat and rubber teat, the teat detaches from the sealing lip of the suction head as well as also from the rubber teat shank. At this moment, all known measures, by which an improvement of the adhesive friction was attained at the beginning of the milking process, are cancelled or greatly restricted in their effect.The adhesive friction between the rubber teat and the teat reduces very greatly already at a very small vacuum in the teat cistern so that the milking bucket creeps up at the teat and udder tissue is sucked into the suction head. This tissue finally fixes the already arisen closure between gland and teat cistern. The milk still present in the gland cistern can no longer flow on. It can only be obtained through manual or mechanical enhancement, for example loading of the milking bucket. Milking buckets of more than average weight can in this labile phase drop off from the teats. Additional mechanical aids make the milking installation more expensive.

According to the present invention there is provided a milking apparatus comprising a sleeve, a tubular rubber insert extending within and surrounded art a spacing by the sleeve, and a suction head provided with a passage opening to receive a teat of an uddertherein and with a sealing surface bounding the passage opening, the insert being provided with holes so arranged that during operation of the apparatus the sealing surface provides a seal with the teat of the udder.

In the use of a two chamber milking bucket, the rubber insert, which is provided with holes and the clear width of which corresponds to the average diameter of the teats, may be inserted in the sleeve which may be in the form of a rubber teat or tube.

The holes can have any desired shape and have a larger cross-section at the side facing the teat. The rubber teat encloses the mould rubber insert and forms the boundary between milking bucket interior space and pulse space. An annular gap is present between moulded rubber insert and rubber teat. This annular gap is connected with a vacuum pump through the milking bucket interior space and milking hose as well as milk collecting container. The vacuum feed to the ring gap may take place through a separate feed duct. The length of the moulded rubber insert may correspond to the length of the teats.

The moulded rubber insert may however have a maximum length equal to the rubber teat. The holes in the moulded rubber insert are preferably arranged directly underneath the suction head so that relatively short teats protrude into the part of the moulded rubber insert provided with holes. In order to prevent that the upper holes being exposed in the case of constrictions of the teat at the teat base towards the end of milking, the moulded rubber insert may be provided at a transition from cylindrical or conical shank part extending into the suction head with an adequate annular sealing surface, in which no holes are present and the width of which amounts to about 25% of the shank diameter. If the annular sealing surface is a lip or bead, the width can be chosen to be smaller.

In order even in the case of short teats to attain a maximum contact with the apertured region of the moulded rubber insert, suction heads which are as flat as possible should preferably be used.

The moulded rubber insert may form a unit with the suction head. In this case, simple hoses can be inserted into the milking bucket sleeves of two chamber milking buckets for delimiting the pulse space. The moulded rubber insert may be used in single chamber milking buckets. In these milking buckets, the annular gap is formed between the moulded rubber insert and the milking bucket sleeve.

The moulded rubber insert can also form one unit with the rubber teat, wherein the connection between rubber teat and moulded rubber insert is possible at the suction head or, in the case of a moulded rubber insert which is as long as the rubber teat, at the lower end of the rubberteatshank.

The outer surface of the moulded rubber insert may have relief portions. It is also possible to provide relief portions on the surface of the rubber teat opposite the moulded rubber insert. The relief portions may comprise channels, grooves, knubs or protrusions or depressions of other kinds and they have the task even in the case of a collapsed rubber teat to maintain vacuum-conducting channels between this and the moulded rubber insert. In this manner, a suction against the teat skin at the perforated rubber teat insert can be assured during the suction phases as well as also during the relief phases. This makes possible an additional increase in the adhesive friction, particularly during the relief phases.

The teat received by the moulded rubber insert is acted upon by vacuum in the shank region during the suction phases. This vacuum gets out of the milking bucket interior space into the annular gap between rubber teat and the moulded rubber insert in two chamber milking buckets or between the milking bucket sleeve and the moulded rubber insert in a single chamber milking bucket and from there through the holes in the moulded rubber insert to the teat skin. In the relief phases, a vacuum decay arises in the region of the holes in the case of two chamber milking buckets and thereby to a reduced vacuum loading on the teat skin in that the collapsing rubber teat covers the holes of the moulded rubber insert and blocks the connection to the vacuum source.During the suction phases, the teat skin is firmly sucked against the perforated moulded rubber insert and also does not detach when vacuum arises in the teat cistern toward the end of milking.

Thereby, creeping-up of the milking bucket at the teat is prevented. Thus, milk can still be sucked off out of the teat until the vacuum in the teat cistern nearly reaches the level of the operational vacuum and a diaphragmlike closure forms at the transition point between gland cistern and teat cistern, which also no longer opens during the relief phases. This closure arises by reason of the pressure difference between the high vacuum in the teat cistern and the atmospheric pressure on the teat parts protruding out of the milking bucket.

The moulded rubber insert receiving the teat may be so reinforced in the region provided with holes that no radial expansion of the teats can take place.

This promotes the adhesive friction between teat and moulded rubber insert.

Cleaning of the moulded rubber insert is assured to the full extent in the use of known ring rinsing processes.

Embodiments of the present invention will now be more particularly described by way of example and with reference to the accompanying drawings in which: Figs. 1,3 and 4 show schematic illustrations of two chamber milking buckets with a moulded rubber insert and Fig. 2 shows a schematic illustration of a single chamber milking bucket with a moulded rubber insert.

A milking apparatus comprising a two chamber milking bucket illustrated in longitudinal section in Fig. 1 is provided with a moulded rubber insert 1, a milking bucket 2 and a sleeve in the form of an elastic rubber teat 3. The rubberteat3 has an equally thick wall at a suction head 9 with a lip 16. The moulded rubber insert 1 is so laid into the rubber teat3orfirmly connected with itthatthe insert is disposed sealingly against the suction head 9. Rows of holes 7 are so arranged at a spacing that a sealing surface 8 remains above the holes. The moulded rubber insert 1 is funnel-shaped in the region of the suction head 9 and structured cylindrically or slightly conically in the shank part. The holes can be cylindrical or enlarge conically towards the teat.The crosssection of the holes 7 is expediently circular, but they may have any other cross-sectional shape. The length of the moulded rubber insert 1 is as a rule shorter than the shank of the rubber teat 3, but it may be the same length. It must however have at least the length of the teat. The number of rows of holes is variable but is expediently three or four. It is insignif icantwhetherthe rubber teat 3 has the length of the milking bucket 2 and is tightened with this by means of a conical insert piece and the milk is guided furtherthrough a separate hose or whether the rubber teat has a hose-shaped projection. Only the technological possibilities of inserting the moulded rubber insert 1 into the rubber teat 3 and to connect this sealingly with the suction head 9 are decisive.

An annular gap 4 must be present between the moulded rubber insert 1 and the rubber teat 3. In order to ensure that the annular gap 4 is always maintained, the surface of the moulded rubber insert 1 may be provided with knubs or protrusions of other kinds as well as with channels or grooves. A flat construction of the suction head 9 is advantageous in order to keep the dimension 'b' as small as possible.

The milking process occurs as follows: The milking bucket 2 is put on in the usual manner in that the milking bucket interior space 6 is evacuated through the milk collecting vessel. The teat is introduced into the opening of the suction head 9 and the milking bucket pushes itself over the teat through the vacuum and manual aid. Propagating through the stub 11 and the pulse chamber 10 is the pulsating vacuum which in the suction phase guides the rubberteat3 back into the normal position, whilst the teat rubber 3 is compressed by means of atmospheric air pressure during the relief phase and the pressure force is transferred to the moulded rubber insert 1 and from this to the teat.This is possible because the air is constantly sucked off and the mi 1k- ing bucket interior space is evacuated to a certain pressure by way of the connection and the milk collecting vessel (not shown). Since an annular gap is present between the moulded rubber insert 1 and the cylindrical hose part of the rubber teat 3, the air is sucked off through the annular gap 4 and the bores 7 at the teat so that the teat is urged against the moulded rubber insert. The teat sucks itself firmly against the bores 7 and the milking bucket is thereby prevented from sliding. Since the sucking-fast does not depend on the filling state of the udder or the tautness of the teat, the milking-bucket is prevented independently of the degree of milking from pushing upwardly and by the suction head 9 finally interrupting the milk flow.

Fig. 2 shows a single chamber milking bucket. The vacuum in the annular gap 4 required for the adhesion of the milking bucket propagates between the milking bucket wall 2 and the moulded rubber insert 1. Merely the rubber teat 3 surrounding the moulded rubber insert 1 is dispensed with. The moulded rubber insert 1 forms one unit with the suction head 9.

Fig. 4 shows substantially the same construction as Fig. 3. It differs in that the moulded rubber insert at the milk suction side has the same length as the rubber teat 3. The rubber teat can be a simple cylindrical hose length. The connection to the annular gap 4 is attained through bores 5.

Fig. 3 shows a two chamber milking bucket with a moulded rubber insert as illustrated in Fig. 2. Here, too, a simple hose suffices as the rubber teat. With progressive emptying of the udder, the volume of the udder reduces underthe influence of atmospheric pressure. The connecting opening 14 between the udder cistern and the teat cistern 13 progressively narrows. Thereby, the flow speed of the milk in the region of the connecting opening 14 increases, particularly at the beginning of the suction phases when the shanks of the rubber teat 3 and the moulded rubber insert 1 open and a vacuum due to flow arises in the region of the connecting opening 14. First diaphragmlike closures of the connecting opening 14 arise at the beginning of the suction phases and, in consequence of the further emptying of the teat cistern 13, the formation of vacuum within the teat cistern.

In use of the embodiments shown in Figs. 1 to 4, the moulded rubber insert at the hose 7 sucks itself fast againstthe teat 12 and prevents the milking bucket creeping up or sucking skin tissue into the suction head 9.

On the relief of the teat, thus when the suction effect is interrupted by the rubber teat, the connection between the udder and teat cistern 14 opens each time and milk flows out of the udder cistern 15 on to the teat cistern 13.

With the moulded rubber insert, withdrawal of milk from the udder is possible until the vacuum in the teat cistern 13 nearly reaches the level of the operational vacuum in the milking bucket intermediate space 6 and the connection 14 between udder cistern 15 and teat cistern 13 then closes off so firmly in consequence of the high vacuum in the teat cistern 13 and the atmospheric air pressure acting from outside on the upper part of the teat 12 that also in the relief phase milk no longer flows from the udder cistern 15 into the teat cister 13.

The gap provided by the moulded rubber insert represents no obstacle to cleaning the milking buckets. It is readily possible with the usual circulating rinsing systems, in which the rubber teat is moved by pulsating air during the cleaning phase to also supply the places accessible with more difficulty with cleaning solution.

An advantage of the above described embodiments is that creeping-up of the milking bucket at the teat in the end phase of the milking process is prevented and it is in a position for gaining the entire yieldable milk as far as possible without manual support or special mechanical devices which act on the milking bucket.

Claims (12)

1. A milking apparatus comprising a sleeve, a tubular rubber insert extending within and surrounded at a spacing by the sleeve, and a suction head provided with a passage opening to receive a teat of an uddertherein and with sealing surface bounding the passage opening, the insert being provided with holes so arranged that during operation of the apparatus the sealing surface provides a seal with the teat of the udder.

2. An apparatus as claimed in claim 1, wherein the insert is at least partially cylindrical.

3. An apparatus as claimed in claim 1, wherein the insert is at least partially conical.

4. An apparatus as claimed in any one of the preceding claims, wherein the suction head is substantially planar and integrally formed with the insert.

5. An apparatus as claimed in any one of the preceding claims, wherein the sealing surface merges into a surface of a ip.

6. An apparatus as claimed in any one of the preceding claims, wherein the sleeve comprises a portion of a milking vessel.

7. An apparatus as claimed in any one of claims 1 to 5, wherein the sleeve comprises a rubber tube.

8. An apparatus as claimed in any one of the preceding claims, wherein at least one of the insert and the sleeve are provided with relief elements to provide the space between the sleeve and the insert at the region of the relief elements.

9. A milking apparatus substantially as hereinbefore described with reference to Fig. 1 of the accompanying drawings.

10. A milking apparatus substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.

11. A milking apparatus substantially as hereinbefore described with reference to Fig. 3 of the accompanying drawings.

12. A milking apparatus substantially as hereinbefore described with reference to Fig. 4 of the accompanying drawings.