GB2146721A - Hose connection - Google Patents

Abstract

The invention relates to a hose 1 with a terminally, firmly incorporated connecting piece 2 provided with annular beads 3, 4 and with intersecting rubber reinforcing inserts (8, Fig. 2) between the inner and outer envelopes. The reinforcing insert comprises a continuous thread passing in steep helical form alternately round the hose, the thread turns being in each case juxtaposed and over a short distance passing behind an annular bead. In alternative embodiments the thread can be formed of synthetic fibres such as polyamide, polyester. or alternatively of steel. <IMAGE>

Description

SPECIFICATION Hose with incorporated connecting piece The invention relates to a hose with a terminaily, firmly incorporated connecting piece provided with annular beads or tori and intersecting rubber reinforcing inserts between the inner and outer envelope.

These hoses can be used as pressure and suction hoses and essentially in all technical fields. The hoses can have a separate inner lining which, if necessary, can also line the inner wall of the connecting piece. The latter is made from metal or a similarly strong plastic.

Large diameter hoses are used for the transfer of large quantities of liquid and have incorporated connecting pieces at their ends.

Due to the considerable transportation distances and the considerable gradients, such hoses have compression strength values which can go well above 50 bar. The hoses can have diameters of 2 to 400 cm. Such hoses are formed from short sections, provided with a connecting piece at either end.

Generally, such hoses are provided with the connecting piece, in that wide strips of fabrics or some other material are wound down into the connecting piece zone on a mandrel and an inner rubber envelope located thereon.

The inserts have an intersecting arrangement, in order to give the hose the necessary strength. To limit the effects of increased pressure on the behaviour of the hose, such fabrics are incorporated in such a way that their thread angle is approximately 55 to the longitudinal axis of the hose. At this neutral angle, the pressure and tension cancel one another out. The fabric insert is fixed to the connecting piece through reinforcing inserts being bound between the annular beads or tori located on the connecting piece. Such fixing means are covered by the subsequently, externally applied rubber surface layers and are consequently not subject to any further inspection. Although such hoses have proved satisfactory, they have weak points at least in the connecting piece area.Apart from the relatively high labour costs in producing such hoses, it has been found that they require more material for their reinforcing inserts than corresponds to the subsequent maximum permitted operating pressure. This is due to the fact that in the case of such a production procedure, it is virtually impossible to introduce the reinforcing inserts in such a way that the thread material thereof is under tensile stress in the same way everywhere and in all the layers.

The problem of the invention is to construct a hose of the aforementioned type in such a way that the manufacture is largely completely automatic and also so that there is uniform stressing of the reinforcing insert in all zones enabling the strength values of the insert material to be utilized into the border region.

According to the invention, this problem is solved in that the reinforcing inserts comprises a continuous thread passing in steep helical form and in alternating manner around the hose, the thread turns being juxtaposed and behind an annular bead pass round the connecting piece in a radial plane over a short distance.

The aforementioned thread can be cord threads, strands or thin wires. The term "threads" is also understood to cover monofilament and multifiiament threads. The material for such threads can be synthetic fibres such as nylon, polyester or aramide, as well as steel and other materials conventionally used in hoses. The material and structure of the thread are a function of the probable intended use.

Such a reinforcing insert can be very satisfactorily applied by means of an electronically controlled winding means. Through a control means, the thread is wound about the hose length which is being rotated about its longitudinal axis. The thread continuously passes in alternating manner over the inner envelope of the hose that the threads are juxtaposed.

As soon as the thread has passed up to the annular bead, the guide stops in the particular position for part of a revolution of the hose blank. As a function of requirements, the short-distance turn behind the annular bead can be approximately between 180 and 90 , without this being restrictive. It is important that a loop is formed behind the bead, which is sufficiently large for it not to slide away.

This is dependent on the friction coefficient of the material and the diameter of the hose.

In the case of particularly large diameters, it also can be appropriate for the annular bead to have pins or other fixing means directed in the axial direction of the hose.

When the winding process has led to a complete covering of the inner hose envelope, then the reinforcing insert provided has been completed. The thus applied threads are characterized by a completely uniform tensile prestressing, so that the thread loading or stressing capacity can be directly equated with that of the hose. Thread guidance also ensures that there are juxtaposed intersection points between the threads, so that the reinforcing insert to a certain extent then has a cloth binding. As is known, this represents a particularly strong structure in reinforcing inserts.

The annular bead should be flattened towards the central part of the hose, so that the thread is always located on an appropriate base. If appropriate, rubber profile rings could be used as a support.

A special feature of such a fixing of the thread is that a precise thread directionqs even maintained in the conically rising area in front of the annular bead. The threads pass from one another in a radial manner in this area.

As a function of the thread thickness and structure, the thread turns behind the annular bead can be juxtaposed and/or superimposed. With the arc or curve length with which the thread passes radially round the hose, it must be ensured that the precise attachment point for the return travel of the thread takes place in the appropriate helical configuration.

The arrangement of the thread turns behind the annular bead should be such that there is a maximum dense packing of all the thread turns. There must be adequate space to ensure that the packing does not exceed the height of the annular bead. If several insert layers are provided in a single hose, they are in each case separated from one another by a rubber layer. The then provided thread layers are then in each case associated with a particular annular bead on the connecting piece.

The annular bead nearest to the central area of the hose is associated with the lower thread layer.

The invention will now be described in exemplified manner relative to three drawings.

Fig. 1 shows a basic cross-section. Fig. 2 shows the thread configuration on a hose part. Fig. 3 shows a cross-section through a particular construction according to the invention.

According to Fig. 1, a connecting piece 2 is provided on the end of a hose 1. Connecting piece 2 is used for supporting reinforcing inserts, which are embedded in hose 1. For the fixing of the inserts, connecting piece 2 has annular beads 3 and 4, behind which can be fixed the reinforcing inserts located in the hose. The connecting piece has a terminal flange 6 with bores 5, which is used for screwing to an adjacent hose section. Such a connecting piece 2 can either be provided on one or both ends of a hose 1.

According to Fig. 2, a thread 8 passes helically around the hose, the hose axis angle being approximately 55 . Thread 8 is guided behind annular bead 7 in the radial plane until it has attained a looping section with a reliable hold. The thread then passes back over bead 7 and runs in the opposite direction parallel to threads 8. The thread is arranged in the same way behind bead 9 and behind bead 7. Rubber rings 10, 11 are arranged at both beads 7, 9, so that the thread 8 is always supported on a firm base.

Fig. 3 shows the cross-section through a hose 12, which is applied to a connecting piece 13. In Fig. 3, there are four layers of thread turns. The thread layers 14 and 18 are fixed behind annular bead 19 and thread layers 15 and 16 behind annular bead 17.

Claims (5)

1. A hose with a terminally, firmly incorporated connecting piece provided with annular beads and with intersecting rubber reinforcing inserts between the inner and outer envelopes, wherein the reinforcing insert comprises a continuous thread passing in steep helical form alternately round the hose, the thread turns being in each case juxtaposed and over a short distance pass in the radial plane around the connecting piece behind an annular bead.

2. A hose according to claim 1, wherein the annular bead is flattened towards the central part of the hose.

3. A hose according to claim 1, wherein the thread turns are juxtaposed and/or superimposed behind the annular bead.

4. A hose according to claim 1, wherein in the case of several thread layers separated by rubber layers, the further inwardly located thread layer is associated with the annular bead nearest to the central area of the hose.

5. A hose substantially as described herein with reference to and as shown in the accompanying drawings.