GB2145915A

GB2145915A - Milk liner claw tube protector

Info

Publication number: GB2145915A
Application number: GB08421924A
Authority: GB
Inventors: David Boast; Roger William Head
Original assignee: Avon Industrial Polymers Melksham Ltd
Current assignee: Avon Industrial Polymers Melksham Ltd
Priority date: 1983-09-02
Filing date: 1984-08-30
Publication date: 1985-04-11
Also published as: GB8421924D0; GB8323595D0; GB2145915B

Abstract

A milk liner claw tube protector 6 consists of a flexible sleeve 7 which fits over the end of a claw tube 3 which receives a claw nipple 1. The sleeve 7 has ribs 11 which extend inwardly towards the tube 3 so that an air pocket 10 is defined between the sleeve 7 and the claw tube 3. When the claw tube 3 bends, the sleeve also bends, but the ribs 11 maintain a gap between them. Therefore, even if an impact occurs when the tube 3 is bent, there will be absorption of the impact by the ribs 11 thereby reducing the risk of damage to the claw tube. One end 9 of the sleeve 7 seals to the claw tube and the other end 8 seals to the claw nipple 1 as this arrangement is easier to assemble than if the sleeve 7 fits completely over the claw tube 3. <IMAGE>

Description

SPECIFICATION Milk liner claw tube protector The present invention relates to a protectorfor protecting the clawtube of a milk liner of a milking machine against damage due to impact.

In a milking machine teat cups are provided which are fitted over the teats of the cow's udder. Each teat cup comprises a metal body containing a flexible liner, the liner being connectedto aclustercommonto a group offourteat cups by a flexible tube known as a claw tube. The claw tube may be integral with the part ofthe liner in the teat cup and fits over a claw nipple projectingfrom the cluster. Alternatively, the claw tube may bea separate piece which is connected to the part ofthe liner in the teat cup.

Figure 1? ofthe accompanying drawings shows a cross-sectional view of a liner claw tube fitted over a claw nipple. Asshown in thatfigure, a claw nipple 1 projects from ac[uster2and a clawtube 3 of a milk linerfits overthe nipple 1.The end ofthe nipple 1 is inclined relativetothe axis ofthe nipple 1. When the teat cup (not shown) atthe free end ofthe clawtube is removed from a cow"s udderthe weight ofthe teat cup bends the claw 3 downwards on the nipple 1 and the portion 4 ofthe clawtubeadjacent and above the free end of the nipple 1 folds over the end ofthe nipple 1 to seal it.The closure ofthe nipple 1 prevents loss of vacuum pressure in the pipe run leading to the cluster 2 and also prevents loss of milkfrom the open milk liner.

A major problem with this arrangement is that the part 4 ofthe clawlube 3 adjacentthe free end ofthe nipple 1 is extremely susceptible to damage due to impact. In certain circumstances the cluster itself may be damaged. Itis not uncommon forthe cow to kick or tread on the claw tube 3 and the usual point of fracture is adjacentthefreeendofthe nipple 1 because the end ofthe nipple l may cutthe claw tube atthat point.

Another cause offracture is impact of the claw tube 3 against a stanchion orwall when the cluster 2 is withdrawnfromthe milking station by automatic retraction equipment The use of such automatic retractionBequipment is becoming increasingly common andthe problems of impact damage become more important Figure2 ofthe accompanying drawings shows a claw tube modified to protect it against impact damage. A plurality of ribs 5 are provided on the claw tube.3 around the part4 ofthattube 3 adjacentthe free endofthe nipple 1. Several different configurations of ribs are known. Figure 2 illustrates a configuration with annular ribs 5 around the clawtube 3 but it is also known to provide ribs which extend along the claw tube 3.It is also known to thicken the material of the clawtube3 at its part 4. All these configurations seek to cushion the claw tube 3 from impact. However, they have a major drawback; they decrease the flexibility of the clawtube 3 adjacentthefree end of the nipple 1.

This reduction in flexibility prevents the clawtube 3 from bending sufficiently to seal the free end of the nipple 1 thereby causing loss of pressureandior loss of milk.

The present invention seeks to provide protection forthe claw tube of a milk liner. In essence, the present invention proposes a protectorfor a clawtube in the form of a flexible sleeve which fits over at least a part ofthe claw tube adjacent the end of the clawtube for receiving a claw nipple. The sleeve and the claw tube thus provide a claw tube assembly with the sleeve resisting impact damage to the clawlube.

As discussed above, one problem with forming a protector integral with the clawtube is that it decreases the flexibility ofthe claw tube. Forthis reason it is preferable that the sleeve is more flexible than the claw tube. One way of achieving flexibility, yet maintaining protection from impacts is to provide at least one gas (usually air) pocket defined bythe sleeve. The gas pocket permits relative movement of parts ofthe sleeve and the clawtube. A plurality of pockets may be provided, indeed the use of sponge rubberwhichhasa multiplicity of pockets would provide adequate protection. However, it is preferable that the gas pocket is between the sleeve and the claw tube.

Ifthe gas pocket closed completely during bending ofthe clawtube, the protection afforded by the sleeve would be reduced as shocks would be transmitted directly from the sleeve to the claw tube. To prevent this it is preferable that means are provided for preventing complete closure ofthe gas pocket, and a suitable way of doing this is to provide inwardly projecting ribs which abut against the outer surface of the claw tube during deformation of the sleeve. The resilience ofthe ribs to deformation then absorbs impacts to the sleeve. The ribs preferably extend circumferentially around the sleeve, although it is possible forthe ribs to have a shorter extent, so that they form these projections.

It is possible for the sleeve simply to fit over the claw tube, however, particularly when there is a gap between partofthe innersurface ofthe sleeve and the clawtube, a problem arises in passing the tube through both ends ofthe sleeve. Therefore it is possible to design the sleeve so that only one end seals to the clawtube and the other end seals directly to the claw nipple. Then it is unnecessary for the end of theclawtubeto pass completely through the sleeve, and also meansthatthe end of the sleeve may be trapped between the end ofthe claw tube and the cluster to prevent axial movement of the sleeve.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figures 1 and 2 show known clawlubes fora milk liner and have already been described; Figure 3 shows a sectional viewthrough a clawtube fitted with a protective sleeve according to the present invention; and Figure 4 shows the protective sleeve of Figure 3 in more detail.

In Figure3a clawtube3 isfitted overa claw nipple I of a milking cluster 2 as in Figure 1. The protector 6 according to the present invention comprises a ribbed sleeve 7, one end 8 of which is fitted overthe claw nipple 1 with the sleeve 7 extending along the claw tube 3to coverthe part of the claw tube 3 covering the free end ofthe nipple 1. The sleeve 7 terminates in a seal 9 around the clawtube 3. The sleeve 7 ofthe protector 6 has inwardly projecting ribs 11 extending circumferentially around the sleeve so that an air pocket 10 is formed between the inner surface of the sleeve 7 and the outer surface ofthe claw tube 3.The radial walls of each rib may be sloped towards each other outwardly as shown in Figs. 3 and 4 or may be parallel with each other according to the impact absorption and flexibility required. When an object hits the sleeve 7 the air in the pocket 10 provides an initial cushioning effect, reducing the force of the impact. Then the inwardly projecting ribs 11 on the sleeve 7 abut against the clawtube 3 and the walls 12 ofthe ribs 11 resist further deformation of the sleeve 7 thereby eliminating or at least ameliorating, the effect of an impactontheclawtube3.

When the claw tube 3 bends downwards in Fgure 3 due to the weight of a teat cup, the upper part ofthe sleeve 7 expands and the lower part contracts axially ofthe clawtube 3. This 'concertina" effect due to the shape of the ribs 11 renders the sleeve 7 extremely flexible so that it does not offer significant resistance to bending ofthe clawtube. The ribbed construction of the sleeve 7 thus combines energy absorbing properties with flexibility.

To fitthe sleeve 7,the claw nipple 1 is fitted through an aperture 13 (Fig.4) attheend ofthe sleeve 7 and a flange 14 atthat end 8 seals the sleeve7to the claw nipple. Then, the clawtube 3 is slid into the aperture 15 on the seal 9 until the free end ofthe clawtube 3 is fitted onto the claw nipple 1. The end 8 ofthesleeve 7 is then trapped between the free end of the claw tube 3 and the cluster 2 thereby preventing axial movement of the sleeve 7.

The sleeve 7 is preferably made of an impact resistant flexible plastics orelastomeric material such as a thermosetting synthetic rubber. It has been found that3 mm deep ribs on the sleeve 7 provide sufficient cushioning and sufficientflexibilityforstandard claw tubes. It may be made in a colour different from the claw tube thereby drawing attention to the vulnerable area ofthattube.

Many other designs of sleeve are possible, and still retain the advantages ofthe present invention. For example, it is possible to have a plurality of air pockets or even use a sponge rubber sleeve, which has a multiplicity of pockets. Alternatively the sleeve could have a plurality of radial flanges or other projections extending outwardly ofthe sleeve so that an object strikes the flanges which deform to absorb the impact.

Claims

1. Aclawtube assembly having a clawtube and a separable flexible sleeve fitting over at least a part of the claw tube adjacent the end of the clawtube for receiving a claw nipple, the sleeve being adapted to resist impact damage to the claw tube.

2. An assembly accordingto claim 1, wherein the sleeve is more flexible than the claw tube.

3. An assembly according to claim 1 or claim 2, wherein the sleeve defines at least one gas pocket adjacent the claw tube to facilitate deformation ofthe sleeve.

4. An assembly according to claim 3, wherein the or each gas socket is defined between a part ofthe inner surface of the sleeve and the outer su rface of the claw tube.

5. An assembly according to claim 4,wherein the sleeve has a plurality ofinwardtyprojecting ribs adapted to abut against the outersurface of the claw tube during deformation of the sleeve and thereby prevent complete closure ofthe gas pocket.

6. An assembly according to claim 5, wherein the ribs extend circumferentiallyaround the sleeve.

7. An assemblyaccordingto claim3whereinthe sleeve is made of sponge rubber.

8. An assembly according to claim:rorclaim 2, wherein the sleeve has projections extending in the radial direction awayfrom the claw tube.

9. An assembly according to any one ofthe preceding claims wherein at least-one end ofthe sleeve issealedtotheclawtube.

10. An assembly according to claim 9 wherein the end ofthe sleevefurthestfrom the end ofthe claw tube for receiving a claw nipple is sealedto the clawtube, and the other end ofthe sleeve has a flange adapted to seal that end of the sleeve to a claw nipple.

11. Aclawtube assembly substantially as herein described with reference to and as illustrated in Figs. 3 and4oftheaccompanying drawings.