Technical field

The present invention relates to hose-couplings and more specifically to a hose-coupling part included in couplings for releasable connection of a delivery hose to a container, for instance.

Background of the invention

Couplings of this kind are used primarily as so-called bottom filling couplings in respect of tank cars or the like, wherein both the male part and the female part of the coupling include self-closing valves which are adapted to open when both coupling parts are locked together- normally with the aid of a bayonet type locking device.

The reference numeral 70 in figure 1 indicates the lower part of a container for instance a vehicle-carried tank that has fixedly mounted on its underside the male part 4 of a hose- coupling. This male part has the form of a tubular nipple which includes a self-closing valve and which forms a spout-like extension of an opening in the bottom of the tank 70 and which is designed to co-act with a female part 2 that is joined to one end of a course hose 70. The female part is intended to be threaded up around the lower end of the male part 4 and is locked firmly thereto with the aid of a bayonet locking device, by rotating the female part 2. The female part also includes a self-closing valve, which, similar to the valve in the male part 4, is opened in response to the two coupling halves being joined together. Conventional male parts include a sleeve in which a piston or plunger 6 is able to move axially and is biased into a sealing position by means of a spring. Figure 2 illustrates one such known hose-coupling part with which when the plunger 6 is in an outer end position it lies in sealing abutment with a shoulder on the sleeve 5, wherein when the spring 7 presses the plunger into its end position, an O-ring 8 seals between the plunger and the sleeve. As the plunger of a female part 2 (see figure 1) presses the plunger 6 into an inner end position against the force of the spring 7, the connection between the two hose-coupling parts is opened.

A known problem is that the content of the tank to which the hose-coupling is fitted may possibly expand as a result of thermal expansion for instance. This will result, in turn, in an overpressure in the male part which makes coupling of the male and the female parts difficult

to achieve, or, at worst, impossible, due to the internal overpressure in the male part. This overpressure in combination with the spring force means that the force required to move the plunger 6 from its outer end position becomes much too large.

Summary of the invention

An object of the present invention is to provide a hose-coupling part with which this problem encountered with known technology is avoided or at least alleviated. More specifically, an obj ect of the present invention is to provide a hose-coupling part with which the pressure between this part and a co-acting hose-coupling part is equalized automatically, therewith eliminating any possible overpressure that may arise when connecting said coupling parts together.

The invention is based on the insight that a sealing plunger can be constructed in two portions, an outer portion and an inner portion, whereby the pressure required to move the outer plunger portion will be generally constant, regardless of the inner pressure in the hose- coupling part.

According to the invention, there is provided a hose-coupling part as defined in the accompanying claim 1.

Other preferred embodiments are defined in the dependent claims.

The inventive hose-coupling part engenders pressure equalization when connecting said part to a co-acting hose-coupling part, thereby avoiding the problem experienced with known technology.

Brief description of the drawings

The present invention will now be described in more detail by way of example and with reference to the accompanying drawings, in which:

Fig. 1 shows the placement of hose-coupling parts on a tank;

Fig. 2 is a longitudinally extending sectioned view of a typical hose-coupling part of prior art technology;

Fig. 3 is a longitudinally extending sectioned view of an inventive hose-coupling part in a closed position;

Fig. 3 A is a perspective view of a cup-like part included in the inventive hose-coupling part;

Fig. 3B is a partially cut-away perspective view of an inventive hose-coupling part;

Fig. 4 illustrates the hose-coupling part in a partially open position; and

Fig. 5 illustrates the inventive hose-coupling part in a fully open position.

Preferred embodiments

A preferred embodiment of a hose-coupling part constructed in accordance with the present invention will now be described.

Figures 1 and 2 illustrate a known hose-coupling and a male part included in the coupling, these known coupling parts having been already described in the foregoing.

Figure 3 is a longitudinally extending sectioned view of a hose-coupling part constructed in accordance with the invention. This coupling part includes a cylindrical male portion, generally referenced 10, that includes a generally cylindrical housing or casing 12. The housing is intended to be screwed onto a tank or the like with the aid of a screw thread 12a. The end of the housing 12 opposite to the screw thread is intended for connection with a female part, as indicated in broken lines. When the coupling parts are in a mutually coupled state, gas or liquid is allowed to flow freely through the two hose-coupling parts, as described more clearly in the following text.

The housing 12 includes a sealing element. This element is generally referenced 20 and includes a piston or plunger 22 which has a circular cross-section and which in its outer end

position, shown in figure 3, is in sealing abutment with the inner side of the housing 12. Sealing is achieved by means of a first 0-ring 24 accommodated in a peripheral groove in the plunger 22. The sealing element 20 also includes a cup-like part 26, which is also shown in perspective in figure 3a. The cup-like part 26 is circular in shape and has a somewhat larger diameter than the outer diameter of the plunger 22 and is disposed axially inwardly of the plunger. As will be seen from figure 3 a, the cup-like part includes a number of slots or notches 26a, which permit a certain degree of flow to take place between the cup-like element 26 and the housing 12 in the respective positions shown in figure 3. The effect of this will be explained in the following text.

A second O-ring 28 is disposed in a circumferential groove in the plunger 22 that faces towards the cup-like element 26. This second O-ring 28 is held in place by a ring of material that has low friction, such as a Teflon ring 30, A flat washer or similar plate 32 is disposed axially inwards of the Teflon ring, followed by an undulating washer or like plate 34, as will be seen from figure 3.

Because the internal diameter of the cup-like element 26 is slightly larger than the outer diameter of the plunger 22, the plunger can be pressed telescopically towards the cup-like element in an axial direction in the position shown in figure 3. The second O-ring 28 seals between the plunger and the cup-like element while the Teflon ring reduces the friction there between. The undulating washer or plate 34 resists movement of the plunger towards the cup- like element so that no external force will act on the plunger in the relative positions shown in figure 3.

Finally, the sealing device includes a shaft 36 which extends between a steering cross and the cup-like element 26 and which may extend axially in the cross. A coil spring 40 is mounted between the cross 38 and the cup-like element 26 and functions to force the cup-like element 26 outwards to the position shown in figure 3.

The construction of the inventive hose-coupling will also be evident from the partially cutaway view in figure 3b. The modus operandi of the hose-coupling shown in figure 3 will now be described in more detail with reference to figures 3-5. The figure 3 illustration shows the hose-coupling in a closed state. Assume that an overpressure prevails in the space defined by the housing 12 and the cup-like element 26. This will mean that it is necessary to overcome a

high pressure force in order to move the cup-like element inwards, i.e. to the left in the figure. When a second hose-coupling part shall be connected to the part shown in figure 3, no pressure will, in this case, be exerted on the cup-like element but will, instead, be exerted on the plunger 22 situated outside the cup-like element. The only force that must be overcome in order to move the plunger 22 inwards is the force exerted by the undulating washer or plate 34 that maintains the spacing between the plunger 22 and the cup-like element 26. The pressure exerted on the plunger 22 by the overpressure brought about by the slots 26a in the cup-like element 26 is negligible in this respect.

When the plunger is moved to the position shown in figure 4, a pressure-equalization takes place in the slots 26a. This means that the gas or liquid present in the housing 12 is allowed to flow through the slots 26a and into the second hose-coupling part, thereby obtaining pressure equalization between the two coupling parts.

The resistance to movement of the cup-like element 26 decreases in keeping with the decrease in the overpressure in the housing 12. As a result, the cup-like element 26 will move inwardly under the action of the external force from the second hose-coupling part after a while. Because the spring force exerted by the undulating washer of plate 34 is greater than the force exerted by the coil spring 40, the undulating washer or plate will return to its starting position and thereby move the plunger 22, so that both plunger and cup-like element 26 will be returned to their original relative spacing.

Figure 5 shows the plunger and the cup-like element 26 in their respective inner end positions, hi this state of the coupling, gas or liquid is able to flow freely through the coupling.

When disconnecting the second coupling part from the coupling part shown in figures 3-5, the coupling is returned to the state shown in figure 3 under the action of the coil spring 40. The hose-coupling part thereby returns to its closed state

Although a preferred embodiment of a hose-coupling according to the invention has been described, it will be understood by the person skilled in this particular art that this embodiment can be varied or modified within the scope of the accompanying claims. For instance, the slots or notches 26b can be replaced with other types of openings in the cup-like element. The undulating washer or plate can be replaced with some other kind of spacer, such

as a coil spring or helical spring that maintains the relative spacing between plunger and cup- element. The design of the cup-like element can also be varied within the scope of the accompanying claims.

Although the hose-coupling part according to the invention has been described as a male part, it will be understood that the female part can, instead, be constructed in accordance with the invention. It will also be understood that the pressure equalizing principle applied in the described hose-coupling can also be applied in other types of couplings.