GB2220242A

GB2220242A - Swageable hose end fitting for very high pressure hoses

Info

Publication number: GB2220242A
Application number: GB8914259A
Authority: GB
Inventors: Colin James Taken
Original assignee: Frederick Duffield Pty Ltd
Current assignee: Frederick Duffield Pty Ltd
Priority date: 1988-06-24
Filing date: 1989-06-21
Publication date: 1990-01-04
Anticipated expiration: 2009-06-21
Also published as: GB2220242B; ZA894696B; GB8914259D0; NZ229658A

Abstract

An end fitting for a very high pressure wire-reinforced hose (11) which is pared and clamped between stem and ferrule members (10 and 25) of the fitting. The stem member (10) has two longitudinally spaced shoulders (17 and 18) which are spaced apart by a circumferential groove (19). The ferrule member (25) incorporates two spaced-apart grooves (32 and 33) which locate about and complement the stem member shoulders (17 and 18), and a shoulder (34) that locates about and complements the stem member groove (19). The various shoulders and grooves in the two fitting members (10 and 25) co-operate to force a projecting end of the hose reinforcement to assume a serpentine path and to positively lock the reinforcement between the two members. Additionally, the ferrule member (25) is formed with a number of inwardly projecting circumferential ribs (30), each of which is surrounded by a circumferentially extending land (37), and the ribs and lands co-operate to effect localised concentrated clamping of the hose reinforcement when the ferrule member (25) is swaged onto the stem member (10). <IMAGE>

Description

HOSE END FITTING FOR VERY HIGH PRESSURE HOSES This invention relates to a hose end fitting for use with spiral wound wire reinforced hoses which are intended to carry very high pressure fluids.

Hoses which carry very high pressure fluids, that is pressures in the order of 5,000 psi, must be capable of withstanding high impact loads that have the effect of substantially increasing the pressure momentarily.

This is particularly so with hoses that are used in hydraulic circuits which incorporate positive displacement pumps. Consequently, hose end fittings that are used for joining such hoses together and for coupling them to supply lines or plant must also be capable of withstanding the impact loads and be capable of maintaining the integrity of the hose-fitting assembly under adverse operating conditions.

This means that an end fitting must be positively locked onto a hose end and that there should not be any relative movement between the fitting components and the portion of the hose end that is actually clamped into the fitting. Also, this arrangement must be maintained during repeated cyclic operating conditions that arise from impact loadings.

Hose end fittings that have been developed to meet these requirements typically have a stem member and a swage body or ferrule that is swaged onto the stem member, with the hose end being clamped between the two components. A projecting end of the hose reinforcement is bared and is clamped in metal-to-metal contact between forward portions of the fitting components.

Also, one of the fitting components is usually formed with a shoulder and the other with a matching recess, so that the projecting reinforcement is actually deformed to follow a tortuous path when clamped between the fitting components.

However, it has been found that the existing hose end fittings have not been able to match the demands that are imposed on hoses in some present-day applications and repeated stressing of the hoses has resulted in relative movement between the hose ends and the fitting components. This in turn has led to failure of the fittings when the relative movement of the components has permitted or caused structural damage to occur in the reinforcement.

The present invention seeks to alleviate or at least diminish these problems by providing a hose end fitting which comprises a stem member and a ferrule member which during assembly is swaged onto the stem member with a pared wire reinforced hose end clamped therebetween. The stem member is arranged to locate within the bore of the hose and it is formed with a through-bore for carrying pressurised fluid. Also, the stem member has a stem portion which is sized to locate within an unpared bore portion of the hose and, located ahead of the stem portion, two longitudinally spaced shoulders that are separated by an intermediate circumferential groove. The stem member further comprises a locking groove that is located ahead of the forwardmost shoulder.The ferrule member has a generally cylindrical hollow body which incorporates a first longitudinally extending region that is sized to overlie an unpared outer covering of the hose, and a second longitudinally extending region which is arranged to overlie a pared region of the hose reinforcement.

The second longitudinally extending region incorporates a series of inwardly projecting circumferential ribs that are positioned to surround the stem portion of the stem member. The ferrule member also includes a third longitudinally extending region which overlies a forwardly projecting portion of the hose reinforcement and which includes two spaced-apart grooves that locate about and complement the shoulders in the stem member.

The third longitudinally extending portion of the ferrule member also includes an inwardly projecting circumferential shoulder that locates about and complements the intermediate groove in the stem member, and the ferrule member has an inwardly directed flange at its forwardmost end that is shaped and positioned to locate within the locking groove when the ferrule member is swaged onto the stem member.

The invention will be more fully understood from the following description of a preferred embodiment of the hose end fitting. Such fitting is illustrated in the accompanying drawings in which: Figure 1 shows a half-sectional elevation view of the hose end fitting, with a ferrule member surrounding but not connected to an associated stem member; Figure 2 shows a view which is similar to that of Figure 1 but with a hose end located between the fitting members prior to application of a swaging force; Figure 3 shows a sectional elevation view of one half of the end fitting following application of an initial swaging force; and Figure 4 shows a sectional elevation view similar to that of Figure 3 but with the ferrule member fully swaged onto the stem member.

As illustated, the end fitting comprises a stem member 10 which is intended to locate within the bore of a hose 11 and which is itself provided with a through-bore 12. The stem member is formed at its right hand end with a stem portion 13 which is located within an unpared region of the hose bore and at the left hand end with a coupling 14. The coupling as such is not relevant to the present invention and it may be in the form of a male coupling or a female coupling.

The stem portion 13 has a generally parallel region which is surrounded by three longitudinally spaced groups of barbs 15, and a tapered end region 16 at its right hand end. Also, located ahead of the stem portion 13 are two longitudinally spaced shoulders 17 and 18 that are separated by an intermediate circumferential groove 19. A locking groove 20 is located ahead of the shoulder 18 and immediately behind a head portion 21 of the coupling 14.

The stem portion 13 nas an outside diameter which is approximately equal to the bore diameter of the hose and, as can be best seen from Figure 2 of the drawings, the outside diameter of the shoulders 17 and 18 corresponds approximately with the inside diameter of the hose reinforcement 22.

The hose end is pared internally and externally to different extents to expose the hose reinforcement 22.

The internal paring is effected so that the hose reinforcement 22 projects over the shoulders 17 and 18, and the external paring results in only a small portion of the outer covering of the hose being located within the end fitting. Thus, the outer case is removed from a major portion of the hose end that is located within the fitting.

The end fitting also comprises a ferrule member 25 which is swaged onto the stem member 10 with the reinforced hose end clamped therebetween. The ferrule member itself has a generally cylindrical hollow body which includes a first longitudinally extending region 26 that is sized to locate about the unpared outer casing 27 of the hose. The first region 26 of the ferrule member includes an inwardly directed nib 28 which functions to bite into the outer casing of the hose and to present a barrier to moisture ingress when the fitting is swaged onto the hose end.

A second longitudinally extending region 29 of the ferrule member surrounds a pared region of the hose end and it is formed with a series of four inwardly directed circumferential ribs 30 that are positioned to surround the stem portion 13 of the stem member. The inside diameter of the ribs 30 corresponds approximately with the outside diameter of the hose reinforcement.

The ferrule member 25 further includes a third longitudinally extending region 31 which is formed internally with two spaced-apart grooves 32 and 33 that locate about and complement the shoulders 17 and 18.

The grooves are separated by an inwardly directed circumferential shoulder 34 that locates about and complements the groove 19 in the stem member.

An inwardly projecting circumferential flange 35 is located at the forwardmost end of the ferrule member 25 and it is shaped and positioned to locate within the locking groove 20 when the ferrule member is swaged onto the stem member.

A series of four circumferential lands surround the outside of the ferrule member, one of which is identified by numeral 36 and occupies substantially the full extent of the third longitudinally extending region 31 of the ferrule member. The remaining three lands, which are identified by numeral 37, extend circumferentially about the ferrule member in the second longitudinal region 29, and they have an outside diameter which is slightly smaller than that of the land 36.

Figure 2 of the drawings illustrates the above described end fitting when the two parts of the end fitting are positioned within and about the pared end of a hose. This figure shows the inter-relationship of the fitting component and the hose end during an initial stage of assembly and prior to the application of a swaging force to the ferrule member of the fitting.

When the end fitting components have been mounted to the hose end in the manner shown in Figure 2, a swaging force is applied to the outer diameter of the ferrule member 25, and the ferrule member is swaged into a first position as shown in Figure 3 of the drawings.

In this first (initial) position the flange 35 is driven into the locking groove 20 and the ferrule member is driven inwardly to initiate deformation of the hose walls and reinforcement in the manner indicated in Figure 3.

Further application of the swaging force on the ferrule member 25 results in the hose casing and reinforcement being caused to flow into and occupy all of the voids that exist between the stem and ferrule members. At the same time, the inwardly directed flange 35 at the forward end of the ferrule member is driven even more positively into the locking groove 20, and the swaging force tends to flatten the lands 36 and 37 on the outside of the ferrule, this resulting in force concentrations being directed through the wall of the ferrule member whereby very positive localised clamping is effected on the hose reinforcement between the stem and ferrule members.

An end fitting of the type as above described has been tested under very high pressure impact loading conditions and, due to the combination of features which are inherent in the construction, the end fitting has been found to cope successfully with problems that could not be overcome by use of prior art end fittings.

Claims

1. An end fitting for use with a very high pressure hose and which comprises a stem member and a ferrule member which, during assembly, is swaged onto the stem member with a pared wire reinforced hose end clamped therebetween; the stem member being arranged to locate within a bore of the hose and being formed with a through-bore for carrying pressurised fluid, the stem member having a stem portion which is sized to locate within an unpared bore portion of. the hose and, located ahead of the stem portion, two longitudinally spaced shoulders that are separated by an intermediate circumferential groove, and the stem member having a locking groove that is located ahead of the forwardmost shoulder; and the ferrule member having a generally cylindrical hollow body which incorporates a first longitudinally extending region that is sized to overlie an unpared outer casing of the hose, a second longitudinally extending region that is arranged to overlie a pared region of the hose reinforcement and which incorporates a series of inwardly projecting circumferential ribs that are positioned to surround the stem portion of the stem member, and the ferrule member having a third longitudinally extending region which includes two spaced-apart grooves that locate about and complement the shoulders in the stem member, an inwardly projecting circumferential shoulder that locates about and complements the intermediate groove in the stem member and an inwardly directed flange that is shaped and positioned to locate within the locking groove of the stem member when the ferrule member is swaged onto the stem member.

2. The end fitting as claimed in Claim 1 wherein the stem portion of the stem member is formed along a major region of its length as a cylindrical body and is formed with a tapered region at the end of the stem portion that is intended to first enter the bore of the hose.

3. The end fitting as claimed in Claim 2 wherein the cylindrical body of the stem member is formed at spaced intervals along its length with a plurality of circumferentially extending barbs.

4. The end fitting as claimed in any one of Claims 1 to 3 wherein the circumferential groove in the stem member has side walls which incline outwardly within increasing diameter of stem member.

5. The end fitting as claimed in any one of Claims 1 to 4 wherein the stem member shoulder which is located adjacent to the stem portion has a side wall which tapers downwardly to merge with the stem portion.

6. The end fitting as claimed in Claim 5 wherein one of the circumferential ribs within the ferrule member is positioned to extend about the tapered side wall of the shoulder which is located adjacent to the stem portion.

7. The end fitting as claimed in any one of the preceding claims wherein the inwardly projecting circumferential ribs and the circumferential shoulder within the ferrule member all have side walls that taper inwardly with decreasing diameter of the ferrule member.

8. The end fitting as claimed in any one of the preceding claims wherein the second longitudinally extending region of the ferrule member is formed externally with a plurality of longitudinally spaced, outwardly projecting circumferential lands.

9. The end fitting as claimed in Claim 8 wherein each of the lands surrounds one of the inwardly projecting circumferential ribs.

10. The end fittings as claimed in any one of the preceding claims wherein the third longitudinally extending region of the ferrule member is formed externally with an outwardly projecting circumferential land which extends for substantially the full longitudinal extent of the third region.

11. The end fitting substantially as shown in the accompanying drawings and substantially as hereinbefore described with reference thereto.