Technical field of the invention

The present invention generally refers to press fittings for systems that operate with pressurised fluids, such as, for example, braking systems for motor vehicles. In particular, the invention concerns a male connector element for press fittings.

Background

Known press fittings for systems that operate with pressurised fluids, in particular compressed air, comprise a male connector element, axially hollow and generally tubular shaped, configured for the sealed connection of a pipe or duct, and a female connector element, also axially hollow, configured for receiving a portion of the male connector element opposite to that to which the pipe or duct is connected, creating a sealed fitting with the latter. The axial locking between the two components of the connector assembly is achieved mechanically typically by pressure, and the pneumatic seal is guaranteed by annular shaped gaskets, typically O-rings, fitted on the male element and/or on the female element.

The female and male connector elements are traditionally made of metal, typically brass, and worked with machine tools, but connector assemblies comprising elements made of plastic materials by means of injection processes are becoming increasingly popular, which allow to substantially reduce the manufacturing costs.

On the surface configured to be fitted in the female connector element the male connector element is typically provided with ridges, which extend circumferentially for creating a fitting by friction with the internal radial surface of the female connector element. In this manner the male connector element is axially locked in the female connector element.

One of the more common problems with press fittings lies in the difficulty of removing the male connector element from the female element, due to the circumferential ridges obtained on the outer surface of the male connector element for achieving the press fitting. The removal is generally needed for maintenance or repair operations. The international publication WO 2007/049969 Al describes a male connector element for press fittings comprising a threading on the portion that, once the fitting or assembly with a female connector element is achieved, protrudes axially from the seat of the latter. By screwing a special threaded ring nut on the threading, the ring nut acts as an extractor for the male connector element once it is in abutment against the female connector element.

It is known that, even if the extraction of the male connector element takes place correctly in an axial direction, it can regardlessly damage the circumferential ridges used for the fitting, and/or the seat obtained in the female connector element, compromising the sealing characteristics of the press fitting when successively reassembling it.

Furthermore, the provision of the threaded ring nut makes the press fitting costlier in comparison to press fittings known in the field. Summary of the invention

The technical problem addressed and solved by the present invention is to provide a male connector element for press fittings which allows the aforementioned drawbacks to be overcome with reference to the prior art.

Said problem is solved by a connector element according to claim 1.

Preferred characteristics of the present invention are the subject of the dependent claims.

One solution according to the present invention is that of replacing the circumferential ridges typical of a male connector element for press fittings with a threading designed to be pressure fitted in the seat obtained in a female connector element. Another solution is that of achieving a manoeuvring portion, for example of a hexagonal shape, on the male connector element, for the disassembly from the female connector element by means of unscrewing.

This combination of characteristics allows the disassembly of a male connector element from a female connector element of a press fitting to be carried out by unscrewing, without the use of additional elements in respect to those that constitute the same fitting, such as is instead the case in the fitting described in the international publication WO 2007049969 Al mentioned above.

In fact, due to the use of a threading, the disassembly manoeuvre simply requires a rotation of the male connector element around the axis of the press fitting, which results in reduced disassembling times in respect to the times required in the case of traditional press fittings.

An advantage offered by the present invention is that of allowing the disassembly of the press fitting without damaging the catching surfaces the male connector element and of the female connector element. It is thus possible to reassemble the same parts after the disassembly, ensuring the same sealing conditions of the original fitting. In other words, the overall configuration of the press fitting in principle, does not entail the replacement of one or both of the components after the disassembly, which offers the further advantage of reducing maintenance costs.

Other advantages, characteristics and operating modes of the present invention will become clear from the following detailed description of some embodiments, shown for exemplificative e and non-limiting purposes.

Brief description of the figures

Reference will now be made to the figures of the attached drawings, wherein:

- Figure 1 is a perspective view that schematically shows a male connector

element according to the present invention;

- Figure 2 is a partial front view that shows a detail of the male connector element of figure 1 ;

- Figure 3 is a perspective view that schematically shows a press fitting comprising the male connector element of figure 1 and a female connector element in which the first is sealingly fitted in the latter.

- Figure 4 is a view in longitudinal section of the press fitting of figure 3.

Detailed description of preferred embodiments

With reference to the figures, a male connector element according to the present invention for a press fitting F is denoted in general by the reference numeral 100.

The male connector element 100 comprises in a known manner, a body 110 having a substantially cylindrical shape in which a through cavity 120 is axially obtained.

The male connector element 100 comprises in a known manner, a tubular insert 200 housed in the through cavity 120. The tubular insert 200 is provided with a seat 210, having a U-shape in longitudinal section, that allows the assembly of a pipe (not shown) in the body 110 of the male connector element 100. The tubular insert 200 is typically provided with one or more ring sealing elements 220 having an O-ring shape adapted to seal the pipe inserted inside the male connector element 100.

The male connector element 100 further comprises engaging means for the assembly, by means of compression in an axial direction, in a female connector element 300 of a press fitting F, shown in the figures 3 and 4. For this purpose, the female connector element 300 comprises a seat 310 having a shape and sizes suited for receiving the male connector element, as will be described in greater detail in the following.

The engagement means, indicated in general with the reference numeral 130, are obtained on the surface of the body 110 designed to be inserted in the seat 310 of the female connector element 300.

The male connector element 100 can furthermore advantageously comprise a flange 140, obtained in an intermediate portion of the body 110, adapted to limit the insertion depth of the male connector element 100 in the female connector element 300.

As is known, the press fitting between the male connector element 100 and the female connector element 300 must be sealed. For this purpose, the male connector element 100 comprises one or more sealing ring elements housed in respective seats obtained in the portion of the body 110 designed to be inserted in the seat 310 of the female connector element 300.

In the illustrated embodiment, for example two O-rings 150, 151 are shown. A first O-ring 150, inserted in a first seat 111 obtained in proximity of the free end of the body 110, acts as a sealing element for the pressurised fluid, while a second O-ring 151, inserted in a second seat 112 is axially spaced by a short distance from the free end of the body 110, acts as a dust seal and, more generally, as a protection element from the atmospheric agents. According to the present invention, the engagement means 130 comprise a threading.

As shown in figure 1 and more particularly, in the detail of figure 2, the threading 130 has an asymmetric configuration comprising a first side 131 tilted by an angle a that ranges between 10° and 20° in respect to an axis A of the male connector element 100 adapted to favour, by way of a wedge, the insertion of the latter in the female connector element 300 by means of axial compression. Said angle is preferably equal to 15 °.

The threading 130 further comprises a second side 132 substantially parallel to the axis A of the male connector element 100 and a third side 133 substantially perpendicular to the axis A. The second side 132 and the third side 133 form a step portion adapted to create, in respect to the seat 310 of the female connector element 300, an undercut capable of effectively countering the axial separation forces between the latter and the male connector element 100. It is in fact known that, the fitting between the two connector elements generates a local deformation of the surfaces in contact.

In the embodiment of the invention illustrated in the drawings, the threading 130 preferably also comprises a radiused portion 134 connecting the second side 132 to the third side 133. This configuration offers the advantage of allowing the insertion of the male connector element 100 in the female connector element 300 without removing material, namely without damaging the seat 310 or the same male connector element.

It is thus possible to prevent the detachment of material fragments that could damage the system under pressure for which the press fitting F is designed.

The threading 130 has a pitch p ranging between 1.5 and 2 mm and a depth t ranging between 0.2 and 0.25 mm, this namely that ensures an efficient catching of the male connector element 100 in the seat 310 of the female connector element 300 without compromising the mechanical characteristics of the two components of the press fitting F. The radius portion 134 has a radius R ranging between 0.1 and 0.3 mm.

For allowing an efficient sealed fitting with the male connector element 100, the seat 310 of the female connector element 300 is slightly conical, for example in the order of 2°, and has a surface roughness in the order of 25 μπι. It is further advantageous to provide a radiused portion (not shown) connected at the top of the seat 310. Said portion, having for example, a radius in the order of a half millimetre, preventing the male connector element 100 from being damaged during insertion in the seat 310 of the female connector element 300 and further acts as a ramp.

The male connector element 100 furthermore comprises a manoeuvre portion

160 obtained in the body portion 110 designed to protrude from the female connector element 300 once the press fitting F is achieved.

In the illustrated embodiment, the manoeuvre portion 160 is for example obtained at the flange 140.

The manoeuvre portion 160 allows the engagement of a tool, for example a spanner or similar, for the disassembly of the male connector element 100 from the female connector element 300.

In consideration of the above, it will be understood that, due to a threading being provided, the disassembly of the male connector element 100 from the female connector element 300 is achieved by rotating and not by pulling as is the case in press fittings known in the field, thus allowing the integrity of the catching surfaces of the two components to be maintained.

Furthermore, the configuration of the engagement means 130 allows one or more further assembling or disassembling steps between the same components to be carried out, always ensuring the efficiency of the sealed fitting F in respect of the pressurised fluid flow.

The manoeuvre portion 160 can have a polygonal shape, for example, hexagonal, adapted to allow the use of a spanner. Alternatively, the manoeuvre portion 160 may have different shapes, for example cylindrical with a textured millerays, knurled or similar working surface adapted to allow the use of normal tweezers.

According to one embodiment of the invention, the male connector element 100 can be made of a brass alloy according to the European law EN 12164 or the European law EN 12165. It is further possible to manufacture the male connector element 100 with plastic materials such as for example, PA GF30, PA 6.10 GF30, PA 12 GF30, PA 12 GF50, EPDM and NBR.

The female connector element can be made of aluminium or can be made of a plastic material such as, for example, PA 6 GF30 or PA 6.6 GF30.

The thermal field of use envisaged for the fitting F according to the invention ranges between -40°C and + 100°C, whereas the working pressures are in the order of 15 bar.

The present invention has been described until now with reference to preferred embodiments. It is clear that other embodiments related to the same inventive core can exist, as defined by the scope of protection of the claims included herein.