AU689597B2 - Improvements in or relating to hose fittings - Google Patents

Description

A.C.J. ENTERPRISES PTY LTD o o~oo *o

AUSTRALIA

Patent Act 1990 COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED: ee "IMPROVEMENTS IN OR RELATING TO HOSE FITTINGS" S o 0 90is 2 7t: This invention is described in the following statement: 21/7/95L117880.SPE,1 -2- This invention relates to the attachment of hoses to metal and other relatively rigid tubular fittings to enable the hose to be connected e.g. to a tap or valve or to another length of hose such as via a similar or complementary metal fitting. The invention relates particularly, although not necessarily exclusively, to fittings such as "hosetails" for rubber hose of the large bore and/or high pressure type.

A significant and long-recognised difficulty is the tendency of a fitting to S. be ejected by fluid pressure within the hose, especially when the fit, e.g. a "hosetail" is inside the hose. Clearly a metal sleeve, however thin, presents a ooooo •1 substantial area in the axial direction, and particularly in the case of a hose of large bore and/or carrying high pressure liquid, the rejective forces can present S formidable problems.

Known forms of hosetail consist essentially of a barbed or serrated tail .e.o portion secured within the end part of a hose by means of bands or clamps.

Many such contrivances are of undesirably low holding capacity often well S: below that of the material of the hose with which they have been used.

Most hoses are manufactured to a safety margin of 4:1 i.e. the "burst" pressure is four times a typical or rated working pressure. However it is common practice to test the fitted assembly to 1.5 or twice the working pressure. Attempts to reduce this "performance gap" have included the hydraulic swaging of fittings to the hose. However hose wall thickness and type of construction can impose severe limitations on the pressure capacity of this method. Also the swaged fittings are not, in general, re-usable. This disadvantage can seriously reduce the cost-effectiveness of the method.

21n/95LP7S80 SPE,2

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Objects of the invention are to provide re-usable hose couplings for both suction and delivery hoses, that can withstand a wide range of rated burst pressures, can be made in a variety of materials, are reliable in arduous and hazardous situations, and which meet or exceed a wide diversity of customer specifications with ample safety margin to promote confidence in the product.

These and other objects and advantages will become apparent hereinafter.

For the purposes of the following description terms such as "front", "forward", "rear" and "rearward" are to be understood as referring to a fitting to a "front" end portion of a hose. That is to say, the fitting forms a forward continuation of the hose itself. Also, although the invention is described with particular reference to a rubber hose, it is by no means necessarily limited thereto.

According to the invention in one aspect we provide a hose fitting, which includes a mechanism attaching to a front end portion of a hose a relatively rigid tubular metal fitting including an inner sleeve having a tail receivable within said end portion; an outer sleeve locatable rearwardly of said inner sleeve to overlap said inner sleeve and to define therewith an annular chamber to receive said front end portion of the hose; a radial compression mechanism squeezing hose material within said chamber against and around the inner and outer sleeves and restraining separation of the hose and the fitting, said S compression mechanism including a thrust mechanism axially insertable between the hose and the rear end of the outer sleeve, said thrust mechanism cooperating with the outer sleeve and compressing the hose radially into contact the said tail; and a locking mechanism, engageable while said compression mechanism is operable, said locking mechanism inter-locking said inner and outer sleeves and said thrust mechanism.

In another aspect the invention provides a hose fitting, which includes a mechanism attaching to a front end portion of a hose a relatively rigid tubular metal fitting including an inner sleeve having a tail received within said end 30/1/98VSAP7880.SPE,3 portion, an outer sleeve located rearwardly of said inner sleeve and overlapping said inner sleeve to define therewith an annular chamber receiving said front end portion of the hose, a radial compression mechanism squeezing hose material of said front end portion of the hose against and around the outside of said sleeve, said radial compression mechanism restraining separation of the hose and fitting, and a locking mechanism engageable while said compression mechanism is operable, said locking mechanism inter-locking said inner and outer sleeves wherein the radial compression mechanism includes a thrust mechanism axially inserted between the hose and the rear end of the outer sleeve, said thrust mechanism cooperating with the outer sleeve and compressing the hose axially into contact with said tail, and wherein the parts to be locked by the locking mechanism include the thrust mechanism and the outer sleeve.

But in order that the invention may be better understood reference will now be made to the accompanying drawings which are to be considered as part of this specification and read herewith. In the drawings: Fig. 1 shows an axial section, a practical embodiment of coupling "loose" So S assembly according to the invention applied to a hose; o:om° Fig. 2 is a view similar to Fig. 1 but omitting the hose; Figs. 3 and 4 are respectively a front elevation and axial section of a bipartite locking ring being part of the assembly shown in Figs. 1 and 2; Figs. 5 and 6 are respectively an axial section, and rear elevation of an outer sleeve or ferrule being another part of the assembly shown in Figs. 1 and 2; e• 3011198VSAP7880.SPE,3 L- I Fig. 7 is an axial section of an inner sleeve being another part of the assembly shown in Figs. 1 and 2; Figs. 8 and 9 are respectively an axial section and rear elevation of a pressure ring/push element being another part of the assembly shown in Figs. 1 and 2; Fig. 10 is a view similar to Fig. 2 of another practical embodiment of coupling assembly according to the invention, very similar to that shown in Figs.

1 to 9 but wherein the outer configurations of the ferrule and locking element are somewhat modified or simplified.

1 Figs. 11 and 12 are respectively an axial elevation and section of the modified locking element; Figs. 13 and 14 are respectively an axial section and elevation of the modified/simplified ferrule, and Fig. 15 shows in further detail various aspects of a compressible thrust compression ring forming part of the assembly.

oomo• Referring to the drawings in more detail there is shown an assembly, substantially entirely of metal, for coupling to the end of hose 15. The assembly includes an inner element or sleeve 16 of which a tail 17 is receivable within end part 18 of hose 15, and an outer element or sleeve 19. Sleeves 16 and 19 respectively define radially outwardly and inwardly addressed serrated frustoconical surface portions 20 and 21 defining a hose-end receiving chamber 22.

Clearly, as 16 moves rearwardly and/or 19 moves forwards, the width of chamber will decrease. Conversely, as 16 and 19 move axially away from each other, chamber 20 expands.

217/95Li7880,SPI3,5 i, -6- The end portion of the hose is thus clamped between the tapered/serrated surfaces of the inner and outer sleeves. The taper tends to act as a wedge, converting the axial thrust to a radial thrust, with increased magnitude according to the taper angle. Serration enhances the grip by tending to prevent the hose from slippage.

It appears that the material of the hose tends to stretch rather than resist the force which tends to separate the fitting and the hose. As the hose S stretches its wall thickness decreases, which tends to reduce the available clamping force and frictional resistance. Flexible thrust ring 23 and pressure :ITf inducing sleeve 24 tend to sustain and maintain the clamping force, increasing friction, and thereby minimising or reducing the tendency of the hose to slip from the coupling.

To secure the assembly, firstly the metal pressure inducing element or sleeve 24 is passed over the hose followed by the rubber pusher or thrust ring 23, followed by ferrule 19. If desired, 23 and 24 may be formed as a thrust eoo oi unit, in which case such a unit must clearly be slipped metal first on to the end of the hose, so that ring 2J is "foremost" in the sense used herein.

With parts 19, 23 and 24 pushed back sufficiently clear of the forward portion 18 of hose 15, inner sleeve 16 is inserted tail first into hose portion 18 and axial compression is applied to squeeze the inner and outer sleeves into the relationship shown in Figs. 1, 2 and 10, progressively squashing the rubber of end 18 within the progressively decreasing width of chamber 22 (Fig. 2).

Thus the tail of the inner sleeve is characterised by an outer rearwardlyconverging frusto-conical surface co-operable with an inner forwardly-diverging 2i /95LP7880,SI, ,6 II -7frusto-conical surface of the outer sleeve to define the aforesaid chamber in which the end of the hose is radially compressed by axial pressure applied to the inner and outer sleeves, e.g. by means of an hydraulic press (not shown).

Under such compression there is a tendency for hose material to be forced or to move or slip backwards relative to the conical surfaces. This tendency can be reduced by the peripheral barbs or serrations formed by or in the surfaces.

Furthermore the compressed hose rubber acts like a spring against the relative axial movement of the inner and outer sleeves. To prevent such movement the sleeves may be locked together as shown by a bipartite locking 'l ring (Figs. 3, 4, 11 and 12).

The compression of which the present invention is capable may be so great as virtually to solidify the rubber. Therefore when the fitting of our invention is complete, the hose end may physically resemble a rigid formation locked by its flare or "bell" against axial movement and further secured by the barbs or serrations engaging with the sleeve serrations which moulded them S when the rubber was relatively plastic. Advantageously, further locking is provided by rubber thrust ring 23 positioned at the rear of hose compression chamber 22.

For this purpose, at the outer sleeve's rear end there may be a portion of somewhat expanded internal diameter to receive ring 23 and behind it the metal pressure inducing sleeve 24 whereby a forward thrust may be applied to the rear face of ring 23. This forward axial thrust is converted to an inward radial thrust by the forward part of ring 23 bearing against rearwardly diverging surface 26 within 19.

21/95LP7880.SI',7

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-8- The ring's axial section may be of D formation as shown, with the convex part facing forwards, i.e. facing the compressed hose material in the chamber.

Any tendency of the hose end to retract will be resisted by the pressure ring.

Indeed the lastmentioned may be so located that any substantial retracting of the hose would have to either break the ring or distort it in a virtually impossible manner.

The dimensions, bulk modulus, coefficient of friction and other physical S properties of the pressure ring may need to be carefully chosen relatively to the thickness and general specification of the hose. Clearly, the ring must not be "i already so rigid as will in effect be nearly a continuation of the outer sleeve 40 material. Equally clearly it must not be so low in modulus as to readily deform under forces which tend to disrupt the connexion.

00 0° It will be seen that Fig. 1 is a "loose" assembly because 23 is not yet compressed. The sleeve 24 has yet to be pushed forwards to the extent permitted by the length of the slots in 19. The volume into which rubber 23 is 0 o o pushed is preferably somewhat greater than that of the rubber itself, to allow for compression of 23.

The means for interlocking the sleeves may include a ring threaded to the outside of a forward portion of the inner sleeve, to be turned until it abuts a flat forwardly directed face of the outer ring to which it can then be bolted.

Additionally or alternatively clamping means may be provided to assist in the locking action. Suitable bolts or other means can also be provided for locking the pressure sleeve to the outer sleeve once the pressure ring has been sufficiently compressed.

21/195LP7880.SP3,8 I II -9- It will be clear from the foregoing that the invention provides a re-usable and relatively simple, strong, secure and versatile hose fitting which is suitable for manufacture in a variety of materials. Se r e e ee ee e 0 6 2117/95L1'7880.S'I',9

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Claims (11)

1. A hose fitting, which includes: a mechanism attaching to a front end portion of a hose a relatively rigid tubular metal fitting including an inner sleeve having a tail receivable within said end portion; an outer sleeve locatable rearwardly of said inner sleeve to overlap said inner slee, 2 and to define therewith an annular chamber to receive said front end portion of the hose; a radial compression mechanism squeezing hose material within said chamber against and around the inner and outer sleeves and restraining separation of the hose and the fitting, said compression mechanism including a thrust mechanism axially insertable between the hose and the rear end of the outer sleeve, said thrust mechanism cooperating with the outer sleeve and compressing the hose radially into contact the said tail; and a locking mechanism engageable while said compression mechanism is operable, said locking mechanism inter-locking said inner and outer sleeves and said thrust mechanism.

2. A hose fitting according to claim 1 wherein the thrust mechanism S" includes a pressure inducing sleeve and a ring located forwardly of the pressure inducing sleeve, said ring being compressible within a variable volume region defined by the hose, the outer sleeve and a forward end of the pressure inducing sleeve to exert a restraining force on the hose and thereby enhance S fastening of the end of the hose.

3. A hose fitting as claimed in claim 2 wherein a forwardly-facing part of the ring is convex shaped.

4. A hose fitting as claimed in claim 3 wherein the portion of the outer sleeve abutting said region includes a rearwardly diverging surface such that a forward axial thrust on the unit is transmitted radially inwardly by the ring. A hose fitting as claimed in claim 3 wherein the portion of the outer sleeve abutting said region includes a rearwardly diverging surface such that a ,.o',rM I forwaru axial thrust on the unit is transmitted radially inwardly by the ring.

6. A hose fitting, which includes: a mechanism attaching to a front end portion of a hose a relatively rigid tubular metal fitting including an inner sleeve having a tail received within said end portion, an outer sleeve located rearwardly of said inner sleeve and overlapping said inner sleeve to define therewith an annular chamber receiving said front end portion of the hose, a radial compression mechanism squeezing hose material of said front end portion of the hose against and around the outside of said sleeve, said radial compression mechanism restraining separation of the hose and fitting, and a locking mechanism engageable while said compression mechanism is operable, said lockirn mechanism inter-locking said inner and outer sleeves wherein the radial compression mechanism includes a thrust mechanism axially inserted between the hose and the rear end of the outer sleeve, said thrust mechanism cooperating with the outer sleeve and compressing the hose S axially into contact with said tail, and wherein the parts to be locked by the S locking mechanism include the thrust mechanism and the outer sleeve.

7. A hose fitting according to claim 6, wherein the thrust unit includ. a pressure inducing sleeve and a ring located forwardly of the pressure inducing sleeve, said ring being compressible within a variable volume region defined by the hose, the outer sleeve and a forward end of the pressure inducing sleeve to exert a restraining force on the hose and thereby enhance the fastening of the end of the hose.

8. A hose fitting as claimed in claim 7 wherein the forwardly-facing part of the ring is convexed shape.

9. A hose fitting as claimed in claim 7 wherein the portion of the outer sleeve abutting said region includes a rearwardly diverging surface such that a forward axial thrust on the unit is transmitted radially inwardly by the ring. 301119gVSAP7880.SPE,3 12 A hose fitting as claimed in claim 8, where,, the portion of the outer sleeve abutting said region includes a rearwardly diverging surface such that a forward axial thrust on the unit is transmitted radially inwardly by the ring.

11. A hose fitting, which includes: a mechanism attaching to a front end portion of a hose a relatively rigid tubular metal fitting including an inner sleeve having a tail received within said end portion, an outer sleeve located rearwardly of said inner sleeve and overlapping said inner sleeve to define therewith an annular chamber receiving said front end portion of the hose, a radial compression mechanism squeezing hose material of said front end portion of the hose against and around the outside of said sleeve, said radial compression mechanism restraining separation of the hose and fitting, and a locking mechanism engageable while said compression mechanism is operable, said locking mechanism inter-locking said inner and outer sleeves wherein the sleeves define radially outwardly and inwardly sloped frusto- S conical surface portions defining a hose end receiving annular chamber, a radial width of which decreases and increases as the sleeves move relatively towards and away from each other, respectively, the radial compression Se mechanism includes a mechanism axially compressing the material of the hose end within said chamber, and wherein the parts to be locked by the locking o: o mechanism includes said inner and outer sleeves.

12. A hose fitting, which includes: a mechanism attaching to a front end portion of a hose a relatively rigid tubular metal fitting including an inner sleeve having a tail receivable within said end portion, said tail having an outwardly facing, first frusto-conical surface portion; an outer sleeve locatable rearwardly of said inner sleeves and having an inwardly facing second frusto-conical surface portion defining within said first 30/Zi98VSAP7a80O.SP,3 13 portion an annular chamber receiving said front end portion of the hose, the radial width of said chamber decreasing and increasing as the inner and outer sleeves move respectively towards and away from each other, respectively; a radial compression mechanism squeezing hose material within said chamber against and around said surface portions, said radial compression mechanisms restraining separation of the hose and fitting; and a locking mechanism, engageable while said compression mechanism is operable, said locking mechanism inter-locking said inner and outer sleeves.

13. A hose fitting substantially as hereinbefore described with reference to the accompanying drawings. DATED this 30th day of January 1998. A.C.J. ENTERPRISES PTY LTD By their Patent Attorneys: CALLINAN LAWRIE a* a. *i *fti 3011198VSAP7880.SPE,3 I ABSTRACT A hose fitting assembly which includes a relatively rigid tubular element, an outer sleeve or element defining with a tail of the element an annular chamber for receiving an end part of the hose, thrust means for compressing the hose axially into contact with the tail, and means for locking the outer sleeve to the inner element and thrust member to complete the fastening. S *C *..CS *ee e 217/i95P780.SPn,12