GB2356906A

GB2356906A - Method of manufactuting a hose coupling

Info

Publication number: GB2356906A
Application number: GB9928408A
Authority: GB
Inventors: Andrew James Heaton
Original assignee: SHAND ENGINEERING Ltd
Current assignee: SHAND ENGINEERING Ltd
Priority date: 1999-12-02
Filing date: 1999-12-02
Publication date: 2001-06-06
Anticipated expiration: 2019-12-02
Also published as: GB9928408D0; GB2356906B

Abstract

A method of manufacturing a hose coupling, for example for a large bore high pressure hose, comprises: <SL> <LI>a) providing a tubular metal body (1,2); <LI>b) machining the external surface of the body to form at least two regions (3, 4, 5) of successively smaller diameter along the length thereof; <LI>c) forming for the or each transition between two adjacent regions a metal ring (11, 12) with an internal diameter corresponding to the external diameter of the smaller of the two regions (4 or 5); <LI>d) sliding the or each ring (11, 12) on to the body so as to locate the ring against the respective transition (7, 8) between regions; and <LI>e) securing the rings to the body. </SL> The rings may be secured to the body by welding, by means of adhesive or by shrink fitting. If desired, a combination of shrink fitting with welding or adhesives can be employed.

Description

A - 1 2356906 METHOD OF MANUFACTURING A HOSE COUPLING

Field of the Invention

This invention relates to a method of manufacturing a hose coupling, for exam- ple for a large-bore high-pressure hose for use in the oil recovery and transportation industry.

Background to the Invention

Hose couplings for flexible hoses are essentially steel tubes having a coupling flange or equivalent at one end and circumferential ribs or the like to lock the flexible hose material on to the coupling. They may be for all types of hose, for example large bore (for example having an internal bore of the order of 0.5m) hoses. In practice, particularly, but not exclusively, for this size of hose, the hose is constructed around the coupling using an elongate jig or lathe on which the couplings (one for each end of the hose) are mounted, with the rubber and reinforcing layers of fabric and wire being built up on the jig to incorporate the couplings into the structure.

is The construction of the couplings is typically carried out by forming a tubular body from sheet metal, or using steel tube for smaller diameter couplings, shaping bars to form rings around the body and welding the rings into place, and then machining the coupling to achieve the desired profile. This method is time-consuming and labour intensive, while producing some variation in the finished coupling. Because each cou pling requires machining to finish it to the desired profile, it is difficult to change produc tion to manufacture a different size or configuration, for example, and delivery times tend to be long.

Summary of the Invention

According to the invention, there is provided a method of manufacturing a hose coupling, the method comprising:

a) providing a tubular metal body; b) machining the external surface of the body to form at least two regions of successively smaller diameter along the length thereof, c) forming for the or each transition between two adjacent regions a metal ring with an internal diameter corresponding to the external diameter of the smaller of the two regions; d) sliding the or each ring on to the body so as to locate the ring against the respective transition between regions; and e) securing the or each ring to the body.

Preferably, two or more rings are fitted to the body. The body can be formed by fabrication from sheet metal or by cutting lengths from tubing.

The ring or rings may be secured to the body by welding, but it is also possible to attach them by other methods such as using adhesive or shrink fitting. In the latter case, the rings are sized such that, at room temperature, their internal diameter is the same as, or very slightly smaller than, the external diameter of the body at the relevant position, the rings then being heated to cause expansion before being slid to the desired positions on the body and cooled or allowed to cool to grip tightly on to the body. If desired, a combination of shrink fitting with welding or adhesives can be employed.

It is advantageous in manufacturing the rings to leave additional metal in the form of a burr on the side of ring which, in use, does not contact the transition or shoulder between the regions. This serves as an indicator during assembly of the cor rect orientation of the ring; the burr prevents the ring abutting the shoulder properly, thus indicating incorrect assembly. When the ring is the correct way round, the burr is simply incorporated into the subsequent weld, if used.

It has been found that hose couplings manufactured in accordance with the method of the invention are accurately dimensioned and shaped without the need to machine the final assembly after welding, thereby significantly reducing costs. Also, since components can be manufactured in batches ready for assembly, the couplings can readily be assembled in any of a number of predetermined sizes and configurations, with the minimum of delay, and orders for custom configurations and sizes can be read- ily accommodated.

Brief Description of the Drawings in the drawings, which illustrate successive stages in the method of the inven tion:

Figure 1 is a cross-sectional elevation showing the body assembled to the end flange, before machining; Figure 2 is a corresponding view showing the components after machining; Figure 3 is an enlarged view of detail A in Figure 2; and Figure 4 is a view corresponding to Figures 1 and 2, showing the rings located on the body, the first ring having been welded into place.

Detailed Description of the Illustrated Embodiment

The body is first assembled from two main components: a steel tube 1, which can itself be fabricated from steel sheet; and a coupling flange 2, which is machined forging. These are joined together by welding. It will be seen that the tube 1 has an initial external diameter slightly greater than that of the flange 2. The body is then ma chined to remove excess metal and to provide on the external surface four regions 3, 4, and 6 of progressively smaller external diameter, providing between them three cir curnferential shoulders 7, 8 and 9, as may be seen from Figure 2. The first shoulder 7 is shown in enlarged form in Figure 3, from which it may also be seen that the inner sur face of the body is machined to increase the internal diameter slightly at a region 10 un derlying the shoulder 7, and the area adjacent to the shoulder where welding of the ring is to take place. The purpose of the region 10 is to compensate for the effect of weld- ing, which is to cause an inward bulging or bowing of the body beneath the ring.

Three rings 11, 12 and 13 are cut from a length of steel tube and are machined to the desired external profile (although shown as a rectangular profile in Figure 4, other shapes may be used, for example chamfered on one corner), and to provide an internal diameter matching the external diameter of the region 4, 5 or 6 on which the ring is to be located. Where the ring is to be a shrink fit, the internal diameter is made very slightly smaller than the external diameter of the corresponding region of the body.

Assuming that shrink fitting is not to be used, the first ring 11 is slid on to the body until it comes to rest against the first shoulder 7, and then the other two rings 12 1 and 13 are similarly located in succession against their respective shoulders 8 and 9. It will be understood that, although Figure 4 shows the body horizontal, in practice it may be desirable to have the body vertical, with the flange 2 lowermost, so that the rings rest against their respective shoulders under the influence of gravity. The rings are then welded to the body on each side of the ring, the third ring 13 in Figure 4 being shown with a weld bead 14 on each side thereof

Claims

1. A method of manufacturing a hose coupling, the method comprising:

a) providing a tubular metal body; b) machining the external surface of the body to form at least two regions of successively smaller diameter along the length thereof, c) forming for the or each transition between two adjacent regions a metal ring with an internal diameter corresponding to the external diameter of the smaller of the two regions; cl) sliding the or each ring on to the body so as to locate the ring against the respective transition between regions; and e) securing the or each ring to the body.

2. A method according to Claim 1, wherein two or more rings are secured to the body.

3. A method according to Claim 1 or 2, wherein the rings are secured by welding.

4. A method according to Claim 1 or 2, wherein the rings are secured to the body by shrink fitting.

5. A method according to Claim 3 or 4, wherein the inner surface of the tubular metal body is machined so as to increase the internal diameter thereof slightly in an area respectively underlying each ring.

6. A method according to Claim 1 or 2, wherein the rings are secured by adhesive.

7. A method according to any preceding claim, wherein the body is fabricated from sheet material.

8. A method according to any preceding claim, wherein the rings are formed by cutting short lengths from a tube.

9. A method of manufacturing a hose coupling, substantially as described with reference to the drawings.