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Title:
HYDRAULIC HOSE COUPLING
Document Type and Number:
WIPO Patent Application WO/2008/141386
Kind Code:
A1
Abstract:
An hydraulic hose coupling system which includes a hosetail with one end adapted conventionally for fitting to a hydraulic hose of a specified diameter; a ferrule and collet for fitting over the hose and a universal seating adaptor and a nut for mating with the hydraulic inlet of the machine. A tubular precursor is provided for the hosetail which includes a metal tube with a leading end and a trailing end and an intermediate zone between said ends which includes at least one circumferential collet retaining groove and an adjacent circumferential arrestor groove for retaining a circlip and optionally one or more circumferential hose retaining grooves between the trailing end and the collet retaining groove. The leading end is adapted to be fitted to a an hydraulic machine using a nut and an adaptor wherein the adaptor is attachable to the free end of the hose tail tube and has an outer inclined face that abuts a corresponding internal inclined face of the nut.

Inventors:
HAYMAN, Lawrence, F. (219 Manly Street, Paraparaumu, Welington 5032, NZ)
Application Number:
AU2008/000719
Publication Date:
November 27, 2008
Filing Date:
May 22, 2008
Export Citation:
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Assignee:
E.R.T.H. HYD PTY LTD (18-20 Cyber Loop, Dandenong South, VIC 3175, AU)
HAYMAN, Lawrence, F. (219 Manly Street, Paraparaumu, Welington 5032, NZ)
International Classes:
F16L33/207; F16L33/22
Domestic Patent References:
WO1999056050A1
WO1994023235A1
Foreign References:
GB1249862A
GB2121133A
GB1065480A
GB973647A
US20040104572A1
EP0879982B1
US20050099005A1
EP0829670B1
EP1273843B1
Attorney, Agent or Firm:
MISCHLEWSKI, Darryl (I P Strategies, PO Box 1254Camberwell, VIC 3124, AU)
Download PDF:
Claims:

CLAIMS

1. An hydraulic hose coupling system which includes a) a hosetail with one end adapted conventionally for fitting to a hydraulic hose of a specified diameter b) a collet adapted to fit over the hose tail c) a ferrule for fitting over the hose d) a universal seating adaptor and a nut for mating with the hydraulic inlet of the machine.

2. An hydraulic hose coupling system as claimed in claim 1 in which the hosetail is formed from cold drawn and annealed steel tube.

3. An hydraulic hose coupling system as claimed in claim 1 in which the free end of the hose tail has an internal chamfer on its leading edge to match a complementary groove in the internal surface of the adaptor.

4. An hydraulic hose coupling system as claimed in claim 2 wherein the hose tail has a leading end and a trailing end and an intermediate zone between said ends which includes at least one circumferential collet retaining groove and an adjacent circumferential arrestor groove for retaining a circlip and one or more circumferential hose retaining grooves between the trailing end and the collet retaining groove.

5. A tubular precursor for a hydraulic hose connector which consists of cold drawn and annealed steel tube with a leading end and a trailing end and an intermediate zone between said ends which includes at least one circumferential collet retaining groove and an adjacent circumferential arrestor groove for retaining a circlip and optionally one or more circumferential hose retaining grooves between the trailing end and the collet retaining groove.

6. A tubular precursor for a hydraulic hose connector as claimed in claim 5 in which the leading end of the hose tail has an internal chamfer on its leading edge.

7. A tubular precursor for a hydraulic hose connector as claimed in claim 5 in which the chamfer is at an angle of from 33 ° to 49°.

8. An hydraulic coupling which includes the combination of a hose tail tube having the trailing end adapted for fitting to an hydraulic hose and the leading end adapted to be fitted to an hydraulic machine using a nut and an adaptor wherein the adaptor is attachable to the leading end of the hose tail tube and has an outer inclined face that abuts a corresponding internal inclined face of the nut.

9. The hydraulic coupling of claim 8 in which the leading end of the hose tail has an internal chamfer on its leading edge to match a complementary groove in the internal surface of the adaptor.

10. The hydraulic coupling of claim 9 in which the chamfer is at an angle of from 33 ° to 49°.

Description:

HYDRAULIC HOSE COUPLING

This invention relates to couplings for hydraulic hoses.

Background to the invention

World wide use of machinery utilising hydraulic circuits demands an efficient repair and replacement service. The industry is usually serviced by mobile operators who usually carry a large inventory of connectors for the variety of machines such a s excavators and loaders used in mining, that need servicing. These usually require a large stock for hose tails, ferrules and nuts in both metric and imperial sizes. There are ten different hose diameters and for each diameter size there are 8 different nuts taking into account differences in threads and interfaces. Prior art couplings use a one piece nut and hose tail which means that a larger number of stock items are required to cope with the various combinations of imperial BSP, metric, Imperial UNF with various thread sizes, pitches and seat angles. USA patent 4111469, 4984826, 5044671 , and 5140738 are examples of these prior art fittings.

Typically hydraulic connectors consist of a steel or alloy tube with a leading end that is flared and is adapted to project into a nut , and a trailing end that is adapted for insertion into an hydraulic hose. These tubes are usually machined from solid metal blocks . The nut is a loose fit so that it can be turned by a spanner. The hose is secured to the trailing end by use of a ferrule with internal barbs. The leading end of the ferrule has an in turned lip that seats in a groove in the tube created by a series of circumferential flanges. When the hose is inserted between the ferrule and the tail the lip registers with the groove and the connector is crimped in a swaging machine to lock the connector to the hose. The nut remains rotatable ready to be screwed to the threaded union on the hydraulic machine. The preference for unitary fittings is widespread but standardisation is unlikely because of the profusion of sizes and threads that already exists in available hydraulic machinery.

USA patent 4498691 addresses the problem of matching a nipple and a swagable ferrule to varying hose sizes and thicknesses.

It is object of this invention to provide a coupling system which reduces the inventory required for servicing all available machinery.

Brief description of the invention

To this end the present invention provides a new system in which the actual number of component pieces in a coupling is increased but the total number of combinations is reduced resulting in lower stocking levels and an improvement in service delivery. The components of the new system are a) a hosetail with one end adapted conventionally for fitting to a hydraulic hose of a specified diameter b) a collet adapted to fit over the hose tail c) a ferrule for fitting over the hose d) a universal seating adaptor and a nut for mating with the hydraulic inlet of the machine.

The proposed system only needs 7 universal adaptors, 7nuts and one hosetail. The hose tail differs from those conventionally available in that it is preferably made from cold drawn and annealed tube which is better suited to forming bent components. Thus in one aspect the present invention provides a tubular precursor for a hydraulic hose connector which includes a metal tube with a leading end and a trailing end and an intermediate zone between said ends which includes at least one circumferential collet retaining groove and an adjacent circumferential arrestor groove for retaining a circlip and optionally one or more circumferential hose retaining grooves between the trailing end and the collet retaining groove. The purpose of the grooves is to retain a circlip and a pair of half collets or a single complete collet which position a ferrule during the formation of a hose to metal connector. A circlip is defined as a conventional circlip with eyes in the ends and near circular springy wire clips capable of gripping the surface of the groove in order to resist removal.

The tubular precursor is preferably made from cold drawn mild steel stock with a wall thickness of 0.9 to 3.25mm. There may be 4-7 hose retaining grooves which cooperate with a ferrule to clamp the hydraulic hose.

Preferably the tubular precursor is formed from metal hydraulic tubing and the grooves are machined into the outer surface and the trailing end is tapered so that it accepts the mouth of the hydraulic hose.

In the prior art the collet was integral with the tube and the tube and collet were machined from solid rod material. Thus the provision of a tubular precursor provides a cost savings particularly for larger diameter hose couplings. The purpose of the collets is to prevent axial movement of the ferrule when it is assembled. This allows the fitter to push the hose onto the trailing end of the hose tube. The assembled tube ferrule and hose is then transferred to the swaging dies of a press to crimp the ferrule onto the tube.

The leading end of the precursor tube accepts a compression fitting that is a brass or alloy metal union. This joins the hydraulic coupling to the hydraulic circuit of the machine.

The precursor has a plain leading end so that a universal adaptor and a nut may be fitted.

In another aspect this invention provides in a hydraulic coupling the combination of a hose tail tube having the trailing end adapted for fitting to an hydraulic hose and the leading end adapted to be fitted to a an hydraulic machine using a nut and an adaptor wherein the adaptor is attachable to the free end of the hose tail tube and has an outer inclined face that abuts a corresponding internal inclined face of the nut. Preferably the free end of the hose tail has an internal chamfer on its leading edge to match a complementary groove in the internal surface of the adaptor. The chamfer is usually between 33 ° to 49° preferably at an angle of 45°.

Detailed Description of the Invention

Preferred embodiments of the invention are described with reference to the drawings in which:

Figure 1 is an exploded view of one embodiment of the invention ;

Figure 2 is a section view of the trailing end of the coupling with a hose attached prior to crimping;

Figure 3 is a side view of the coupling with the hose crimped to the tube prior to fitting the compression fitting to the leading end of the coupling;

Figure 4 is a section view of the complete coupling;

Figure 5 is a section view of the trailing end of the coupling prior to swaging;

Figure 6 is a section view of the trailing end of the coupling after swaging;

Figure 7 is a section of the leading end of the fitting of figure 4 with a barbed cone seating adaptor;

Figure 8 is a section of the leading end of the fitting of figure 4 with a BSP adaptor;

Figure 10 is a section of the leading end of the fitting of figure 4 with a seating adaptor incorporating a pair of electronic seals;

Figure 11 is a side view of a hose tail according to a second embodiment of the invention;

Figure 12 A is a detail of the grooves in the intermediate section of the hose tail of figure 11 and figure 12 B is a profile of the leading end of the hose tail of figure 11 ;

Figure 13 is a section view of a collet for the trailing end of the hose tail of figure 11 ;

Figure 14 is a section view of a ferrule for the trailing end of the hose tail of figure

11;

Figure 15 is a section view of a nut for the leading end hose tail of figure 11 ;

Figure 16 is a plan of the nut of figure 15;

Figure 17 is a section view of an adaptor for the nut of figure 15 and hose tail of figure 11.

In figure 1 the steel tube 2 has a trailing end 4 with a taper 6 adapted to receive the hydraulic hose 8. The groove 16 in the trailing end 4 is for gripping the hose 8. The leading end 10 of tube 2 receives a compression union 12 with a revolving nut 14 and an olive . The ferrule 15 fits over the tube 2 so that hose 8 lies between. The intermediate zone 18 of the tube 2 has a circumferential groove 20 adapted to receive a spring circlip 22.

As shown in figure 2 to the rear of the groove 20 are a pair of collet grooves 24. The front wall 26 of each groove is inclined forwardly at 45° to accommodate a pair of complementary shaped steps 28 projecting inwardly from split collet 30. The collet has a tapered outer wall 32 and an annular end wall 34 flush with the rearward groove.

Hydraulic hose 8 incorporates the standard reinforcement 36. The mouth of the hose slides over the trailing end 4 of the tube 2 and abuts the end wall 34 of the collet 30. Ferrule 15 has a skirt 38 with inwardly directed barbs 40 intended to cooperate with the corresponding grooves 16 in the tube. The hose lies between the tube surface 42 and the barbs 40.

The ferrule neck 44 is smaller in diameter than the skirt and the resultant taper is preferably 30°. The bore 48 in the neck is also tapered and corresponds to the collet taper preferably 30°. The length of the neck approximates the length of the collet 30 but extends in front of the collet to abut circlip 22.

In use the tube is selected to suit the diameter of the hose. The collet grooves 24 are greased and the half collets or a whole collet is pushed into the grooves 24. Ferrule 15 is slid backward onto the tube until the neck taper abuts the collet 30. Circlip 22 is slid on the leading end of the tube until it abuts neck of the ferrule and thus the ferrule is captured on the tube.

The hose and ferrule are the placed in a swaging die(schematically shown in figure 4) of an hydraulic crimping machine and compressed to grip the hose. The compression union is then chosen to suit the hose diameter and joined to the machine fitting 46 being serviced. The compression union is locked to the tube by tightening the nut 14 (figure 4). Olive 82 penetrates the tube surface and shoulder 44 seals against the end of the tube. Part 46 belongs to the hydraulic machine(not shown). The male thread on part 46 must be matched by the female thread on the nut 14 forming part of the fitting.

In figure 5 the parts are the same as in figure 2 except that the ferrule is of larger diameter to accommodate the high pressure hose 8 which has additional reinforcement. An anvil zone 50 lies between the rearmost collet groove and the nearest hose groove 16. This zone is occupied by steel sleeve 52 the internal diameter of which is a slide fit on tube 2. The internal cylindrical face of sleeve 52 has teeth 54. Which are hardened in order to bite into the tube during swaging. The external face of sleeve 52 has a groove 56 with inclined sides which lies beneath barb 40. The mouth of the hose is internally skived to create a recess 58 for the sleeve. As the teeth 54 point to the trailing end the sleeve can be inserted into the recess and together pushed into the annular gap between the ferrule and the tube until the end of the hose meets surface 54. The sleeve then lies in the anvil zone 50. In figure 6 the sleeve teeth have penetrated the tube surface and the hose has been forced into the grooves 16 creating a labyrinth seal between the trailing end of the tube and the surface 34.The ferrule barbs produce a hard lock seal in the anvil zone, a soft lock seal opposite grooves 16 and a weather seal at bead 60.

In figure 7 the hydraulic machine part 46 has a male(in this case BSP) thread 70 surrounding the countersunk end 72 and a rear cone face78 which abuts the tapered face of nut 14. The internal surface of seating adaptor 74 has a shoulderδO and forwardly directed barb teeth 82. During fitting the teeth 82 are a slide fit over tube 2 but when nut 14 is tightened on thread 70 the teeth engage the tube 2 and the seating adaptor 74 is trapped between the countersunk end 72 and the end of the tube 2.

Figure 8 is similar to figure 7 except that face 76 of the seating adaptor 74 is not conical but arcuate giving it a bull nose appearance. In figure 9 the leading end of tube 2 has a pair seating adaptor retaining grooves 84. The seating adaptor 74 is similar to those in figures 7 and 8 except that it engages the grooves 84 and includes a seal groove 86 for inclosing a an O ring 88 between tube 2 and the seating adaptor 74. This O ring may be added in high pressure applications to provide a seal against hydraulic oil that may pass the shoulder 80 and the end of tube 2.

The figure 10 variant is similar to figure 9 except that an additional O ring 90 is housed in seal groove 92 in the conical face 76.

The front of the ferrule is partially closed to produce an inwardly facing tongue or barb. The hose tail has two raised flanges projecting outwards with a gap between them , wide enough to receive the front of the ferrule. The ferrule is aligned with the gap and then swaged locally with narrow dies to press the tongue into it; this retains the ferrule on the hosetail in both directions to permanently attach it.

A second embodiment of the invention is illustrated in figures 11 to 17.

The components are a hose tail 100 a collet 110 a ferrule 120 a nut 130 and a universal seating adaptor (USA) 140.

The hose tail 100 is formed from suitably sized hydraulic tube of cold drawn steel and is machined to provide at its leading end 101 an inclined internal surface or chamfer 106. Hose retaining grooves 103 are provided adjacent the trailing end and the number vary according to the diameter and length of the tube 100. The collet retaining grooves 104 incorporate one inclined side on the leading edge side of the grooves. There may be more than two grooves 104 when a larger diameter tube is used. The circlip groove 107 marks the location of the end of the ferrule. The

grooves 105 have inclined sides on the trailing edge side and these are to accommodate the universal sealing adaptor 140 for the nut 130.

As shown in figure 13, the collet 110 has a leading face 113 and a trailing face 112 and an inclined external face 111. Internally the conical collet 110 has internal grooves and ribs 114 with inclined surfaces that mate with the collet retaining grooves 104 of the hosetail 100.

As shown in figure 14, the ferrule 120 has a leading end 121 and a trailing end 122 and an external inclined face 123 at the leading end. Internally the ferrule has at its leading end 121 , an internal inclined face 124 that abuts the collet face 111 and a second inclined face 125 to accommodate the end of the hose (not shown). The internal barbs 126 are designed to bite into the hose when the ferrule is swaged and are inclined toward the leading end to prevent withdrawl of the hose. A circlip or O ring (not shown ) in groove 107 of the hosetail 100 locates the ferrule 120 in position for swaging.

At the machine connection end (leading end) of the hose tail the nut 130 and the

USA 140 are fitted.

As shown in figures 15 and 16, the nut 130 includes an internal thread 132 at its leading end 131. The trailing end 133 of nut 130 is adjacent the leading end 121 of the ferrule 120. Internally the nut includes at its trailing end a USA engaging inclined face 134.

As shown in figure 17, the USA 140 has a leading end 141 and a trailing end 142.

The external inclined face 143 at the trailing end of USA 140 engages the face 134 of the nut. The internal groove and rib 144 engages the USA retaining grooves 105 of hosetail 100. The internal face 146 of the leading end 141 may be horizontal or any angle greater than horizontal and extends back to form a rearwardly projecting rib and associated groove 145 that is shaped to receive the inclined leading edge

106 of the hosetail 100. The angle of the mating surfaces 145 and 106 is preferably

45°. It is possible to design the external faces of the USA 140 to suit more than one nut type further reducing the inventory required.

As the nut is tightened the leading edge141 of the USA 140 is restrained by the machine fitting not shown so that the USA 140 collapses onto the hosetail 100 and the ribs and grooves 105 and 144 mesh as does the leading edge 106 and groove

145 to provide a metal on metal pressure seal.

From the above it can be seen that this invention provides a unique solution to the problem of inventory size for hydraulic hose couplings. It also provides a solution that is cost effective and cost saving in the larger fitting sizes. Those skilled in the art will realise that this invention can be implemented in embodiments other than those described without departing from the core teaching of the invention.