TECHNICAL FIELD

The invention relates to a hydraulic or pneumatic connector comprising a hollow stem having a head and a hose tail to which a hose can be secured, and a swivel nut mounted around the stem for connecting the head to a mating connector.

BACKGROUND OF THE INVENTION

Ever since high pressure hydraulic / Pneumatic assemblies were developed, there have been frequent accidents related to the partial or complete disconnection of the fittings. In the best case, a partial disconnection causes leakage of the fitting and leads to different levels of hydraulic fluid contamination/pollution/fire hazard. In the worst case the discharge of high pressure hydraulic fluid can cause severe injury or death to personnel in the area. In addition, when unsecured hoses become disconnected, they have within them a large amount of stored energy and tend to flail about in a manner that has caused a significant number of fatal accidents.

As these assemblies are used in a myriad of fluid power applications in different industries and countries, gathering data on the level of injuries / fatalities is difficult. As an example, in 201 1 the NSW Government in Australia undertook a review of "escape of fluid" incidents, reportable under the NSW Coal Mine Health &Safety Regulation 2006 (NSW Department of Industry & Investment, 201 1). This review documented 1, 186 "escape of fluid" incidents reported between 2007 and 2010. In this 4 year period 152 people were exposed to near misses or injury across 42 (of a total of 86) NSW Coal mines.

Common causes of such partial or complete disconnection accidents relate:

• Unsecured hoses, leading to unscrewing of fittings as a result of vibrations from cyclic loading.

• Poor installation practices leading to under or over tightening.

• Relaxation of threads after loading.

Previous related inventions include US Patent No: 4,643,459 which covers a quick fit coupling, US Patent No: 4,583,769 for a locking assembly of a different design and US Patent Application No: 2010/0072, 745 for a device that prevents a hose or fitting from disengaging a locking fitting.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a hydraulic or pneumatic connector which has a reduced risk of being unscrewed during operation.

This object is at least to some extent solved by providing the hydraulic connector mentioned initially, wherein the stem comprises a mid-section between the head and the hose tail. A locking collar and a spring are mounted around the midsection, and the swivel nut is positioned between the head and the locking collar. The spring urges the locking collar in a direction along the midsection towards the head, wherein the locking collar is configured to be set in two modes:

1) a non-engaging mode at a pre-determined distance from the head in which the locking collar being prevented from moving towards the head such that it does not pressingly engage the swivel nut, thereby allowing the swivel nut to freely rotate relative the stem; and

2) an engaging mode in which the locking collar pressingly engages the swivel nut, locking the swivel nut from rotation relative the stem.

Preferably, in the engaging mode, the locking collar being movable along the mid-section while at the same time being prevented from rotation relative the mid-section. The locking collar being urged by the spring to pressingly engage the swivel nut towards the head, in which engagement a locking structure of the locking collar being configured to interact with the swivel nut to prevent the swivel nut from rotation relative the locking collar. Thereby the swivel nut is locked from rotation relative the stem

Preferably, the locking collar having a cut-out defined by inner walls. The inner shape of the cut-out matches the outer shape of the midsection in such manner that the locking collar is prevented from rotation relative the mid-section when positioned between the pre-determined distance and the head. At the same time the locking collar being movable along the midsection, from the pre-determined distance to the head.

Preferably, the inner shape of the cut-out is substantially identical to the outer shape of the midsection from the pre-determined distance to the head. Preferably the lateral cross section of the midsection has a non-circular outer shape between the pre-determined distance and the head. The term non-circular outer shape means shapes where the distance to a central-axis is not the same for all points on the periphery. Preferably, the outer shape of the cross-section is constant between the predetermined distance and the head, i.e. such that it does not change between the pre- determined distance and the head.

In one embodiment, the outer shape of the mid-section, between the pre-determined distance and the head, corresponds to a cross-sectional shape provided by cutting off one segment from a circle.

Preferably, the outer shape of the midsection, between the pre-determined distance and the head, corresponds to a cross-sectional shape provided cutting off two opposing and parallel segments from a circle, thereby providing two flat opposing surfaces and two curved opposing surfaces. However, many other forms of constant and non-circular outer shapes are of course conceivable.

Preferably, the midsection has a reduced cross-section portion at the pre-determined distance, the reduced cross-section portion sufficiently reduced to allow the locking collar to be turned relative the stem such that the cut-out of the locking collar can be misaligned with the outer shape of the midsection, thereby providing the non-engaging mode at predetermined distance from the head in which the locking collar is prevented from moving towards the head.

Preferably, the locking structure includes at least one projecting grip surface arranged to mate at least one flat of the swivel nut when the locking collar is set in the engaging mode, thereby preventing the swivel nut from rotation relative the locking collar. More preferably, the locking means includes at least two projecting grip surfaces extending parallel to each other and to the stem in the direction towards the head, the projecting grip surfaces arranged to fit across two opposing flats of the swivel nut when the locking collar is set in the engaging mode, thereby preventing the swivel nut from rotation relative the locking collar. It should be noted that many other forms of locking means are conceivable. Preferably, the spring is provided between the locking collar and a washer contained on the midsection by a retaining circlip secured in a groove at the end portion of the midsection facing the hose tail. The hydraulic connector can suitably be used in a hydraulic or pneumatic apparatus. Such apparatus can include at least one hydraulic/pneumatic motor, at least one hydraulic/pneumatic cylinder, at least one control valve, and at least one hose using the connector.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a shows a hydraulic connector in the locked engaging mode.

Fig. 2 shows a shows a hydraulic connector in the un-locked non-engaging mode.

Fig 3A shows a 3D view of the stem section of the hydraulic connector.

Fig. 3B shows a 2D view of the stem section of the hydraulic connector.

Fig. 3C shows a cross-section of the midsection

Fig 4 shows a locking collar of the hydraulic connector.

Fig. 5 shows some examples of possible configurations a-e of non-circular outer shapes of the midsection.

Fig. 6 shows an example where the the locking collar have a cut-out defined by inner walls. DETAILED DESCRIPTION

Fig 1 and 2 shows a hydraulic connector 100 comprising a swivel nut 1, a locking collar 2, a helical compression spring 3, a washer 4, a hollow stem 5, and a retaining circlip 6. Fig. 1 & 2 demonstrate a locked engaging mode resp. an unlocked non-engaging mode. The hollow stem 5 is shown in more detail in Fig. 3A-3C. The stem 5 has a barbed hose tail 8 (the barbs only shown in Fig. 1 and 2) to which a hose can be attached, a head 10 comprising a flange 11, and a midsection 12 between the head 10 and the tail. In the shown example the head 10 has a cone seat. A through-hole 13 runs through the stem 5 starting at a free end of the hose tail 8 and ending in an opening at the head 10. The lateral cross-section of the midsection 12 having a constant outer shape along its entire length apart from a machined groove 15 at an end portion of the midsection near the hose tail 8 and a reduced cross section portion 16 between the machined groove 15 and the head 10 at a pre-determined distance from the head 10. The outer shape of the midsection 12 corresponds to a shape cutting off two opposing and parallel segments from a circle, providing two flat opposing surfaces 18, and two curved opposing surfaces 19. The flat surfaces 18 between the groove 15 and the hose tail 8 enabling access for a wrench. Returning to Fig. 1, the swivel nut 1 is brought along the stem 5. The swivel nut 1 having an inner threaded section with an inner diameter larger than the outer diameter of the flange 11 and an inward projecting rim (not shown) with an inner diameter large enough to allow free rotation around the midsection 12 but smaller than the outer diameter of the flange 11, such that when the nut 1 is screwed on to a mating threaded male connection (not shown) the inner inward projecting rim of the nut 1 will pressingly engage the flange 1 1 of the head 10 and thereby bringing the head 10 into engagement with the mating connection (not show). The spring 3 is provided between the locking collar 2 and the washer 4 that is secured by a retaining circlip 6 in the groove 15. The spring 3 urging the locking collar 2 in the direction towards the head 10 of the stem 5. In the mode of Fig. 1 the spring 3 urges the locking collar 2 to engage the swivel nut 1. The locking collar 2, shown in in more detail in Fig 4, comprises a flat body 20 having a cut-out 25 defined by inner walls 21 providing an inner shape matching the outer shape of the midsection 12. The locking collar 2 can be set in two modes, a non-engaging mode and an engaging mode. The non-engaging mode is provided at pre-determined distance from the head 10. At the pre-determined position the reduced cross-section portion 16 is sufficiently reduced to allow the locking collar 2 to be turned relative the stem 5. Thereby the cut-out 25 of the locking collar 2 can be misaligned with the outer shape of the midsection 12 to provide the non-engaging mode of the locking collar 2 in which the locking collar 2 is urged towards the head 10 by the spring 3 but prevented from sliding towards the head 10 due to the misalignment. When the locking collar 2 is set in the non-engaging mode, the swivel nut 1 is allowed to freely rotate relative the stem 5, allowing it to be screwed onto a mating male part. This non-engaging mode is shown in Fig. 2. From the non-engaging mode the locking collar 2 can be set in the engaging mode by rotating the locking collar 2 relative to the stem 5 aligning the cut-out 25 with the outer shape of the midsection 12.

The engaging mode is set by aligning the cut-out 25 with the outer shape of the midsection 12, such that the locking collar 2 can be moved along the mid-section 12 towards the head 10. At the same time it is prevented from rotation relative the mid-section 12 since the cut out 25 matches the outer shape of the midsection 12. In this mode the locking collar 2 is urged by the spring 3 to engage the swivel nut 1. Locking means, in the form of a pair of projecting grip surfaces 22 extends perpendicular from the flat body 20 at opposing sides thereof with the cut-out 25 centered in-between. The projecting grip surfaces 22 extending parallel to each other and to the stem 5 in the direction towards the head 10. The projecting grip surfaces 22 arranged to fit across two opposing flats of the swivel nut 1 when the locking collar is set in the engaging mode, thereby preventing the swivel nut 1 from rotation relative the locking collar 2. If the grip surfaces 22 do not immediately fit across die flats of the nut 1, it is simple to rotate the swivel nut 1 slightly until the locking collar 2 clicks into place and locks the nut 1 in place. This mode is shown in Fig. 1.

A pair of opposite located grip wings 23 further extends from two opposing sides of the flat body 20, also with the cut-out 25 centered in-between. The grip wings 23 positioned 90 degrees shifted relative the grip surfaces 22. The grip wings 23 enables a user to push the locking collar 2 from the engaging mode, of fig 1, to the reduced cross-section portion 16 and turning the locking collar 2, e.g. 90 degree, to the non-engaging mode of Fig.2.

The hydraulic connector 100 is assembled by sliding the swivel nut 1 over the hose tail 8 and the midsection 12 of the stem 5 until the inward projecting rim engages the flange 11 of the head 10. Next the locking collar 2 is slid over the hose tail 8 of the stem 5 and locating it beyond the reduced cross-section part 16 of the stem 5. Next the spring 3 is installed below the locking collar 2, followed by the washer 4 and the retaining circlip 6 that is secured at the groove 15.

A hole may be provided in the locking collar 2 to allow tagging in circumstances such as the use of soft seal connectors where the torque needs to be carefully controlled to avoid under or over tightening, which often leads to leaks.

The whole stem 5 should ideally be manufactured from one piece of material. The stem 5 is designed with section sizes that allow it to be stronger than assemblies that are either side of it. Wherever there are reductions in the material cross-section, the tendency for stresses to be focussed at the corners of these changes in section has been reduced in this design by the use of a radius at the bottom of these sections, e.g. in the reduced cross- section portion 16 in Fig. 3A-B. As this design uses cross-sections that are significantly stronger than other parts of the connections, the choice of materials from which it is manufactured can remain as it is for the connections on either end. In the final application the spring-loaded hydraulic connector is likely to have been supplied as a pre-assembled system.

The invention can be used on flexible hoses and can be adapted for any type of hose assemblies / combination of fittings i.e. Thread interface, O-ring, Matching angle, Metal to metal or Mated angle with O-ring. In the non-engaging mode (fig. 2) the nut 1 of the screw fitting is free to rotate such that it can be tightened to the correct torque. A simple turn on of the flattened part of the stem 5 below the washer 4, causes the spring 3 to activate the locking collar 2 and the nut 1 of the fitting is effectively locked in place and cannot become unscrewed fig. 1.

Fig. 5 shows some examples of possible configurations a-e of non-circular outer shapes of the midsection 12.

Fig. 6 shows an example where the the locking collar 102 has a cut-out 125 defined by inner walls 121. The inner shape of the cut-out 125 matches the outer shape of the midsection 1 12 in such manner that the locking collar 2 is prevented from rotation relative the mid-section 112. However, as can be seen in this embodiment the inner shape of the cut-out 125 is not identical to the outer shape of the midsection 1 12. In this embodiment the midsection 1 12 has two protruding profiles 130 that can match cut-out pockets 126. Hence, in this embodiment the locking collar is be aligned with the mid-section 112 every 90 degrees.