WO2019158098A1

WO2019158098A1 - Compression fitting with a securing means

Info

Publication number: WO2019158098A1
Application number: PCT/CN2019/075022
Authority: WO
Inventors: Ernest Chong Tian YUEN
Original assignee: Norma China Co., Ltd.
Priority date: 2018-02-14
Filing date: 2019-02-14
Publication date: 2019-08-22
Also published as: MY191096A

Abstract

A compression fitting (1) comprising a receiving fitting (5) having an internal cavity (7) extending along a longitudinal axis (L) of the receiving fitting (5) for accommodating a conduit, and having a radial axis (R) perpendicular to the longitudinal axis (L), a compression ring (20) configured to be arranged at least partly within the receiving fitting (5) and having a first compression surface (21), the compression ring (20) comprising a first longitudinal end (22) arranged to face towards the receiving fitting (5) and a second longitudinal end (23) arranged to face away from the receiving fitting (5) when the compression ring (20) is arranged within the receiving fitting (5), a union nut (30) configured for attachment with the receiving fitting (5) and having a second compression surface (32) configured, when the union nut (30) is attached with the receiving fitting (5), to engage the first compression surface (21) of the compression ring (20) and cause the compression ring (20) to move radially inwardly for gripping the conduit, wherein the compression ring (20) and the receiving fitting (5) comprise a securing means (40) for securing the compression ring (20) within the receiving fitting (5).

Description

Compression Fitting with a Securing Means

Technical Field

The invention relates to a compression fitting according to the preamble of claim 1.

Background Art

Compression fittings are a type of connector well known in the art for connecting a conduit to another conduit or for securing a conduit within a fitting, and generally comprise a receiving fitting, a compression ring, and a union nut. The compression ring is typically arranged within the receiving fitting and around a conduit, such that when the union nut is tightened onto the receiving fitting, the compression ring is compressed around the conduit to tightly hold it.

Prior art devices have suffered the disadvantage that the various parts of the compression fitting are not secured together before tightening, which has meant that, for instance, the union nut is liable to fall out of the compression fitting when a user wants to assemble or disassemble it. This problem has arisen in particular during the disassembly and remounting of pipes and has been especially problematic in cases where this activity has to be carried out many times.

The present invention is directed to solving this problem. Main features of the invention are described in claim 1 and additional optional embodiments are the subject of claims 2 to 14.

Summary of the Invention

In a compression fitting comprising a receiving fitting having an internal cavity extending along a longitudinal axis of the receiving fitting for accommodating a conduit, and having a radial axis perpendicular to the longitudinal axis, further comprising a compression ring configured to be arranged at least partly within the receiving fitting and having a first compression surface, the compression ring comprising a first longitudinal end arranged to face towards the receiving fitting and a second longitudinal end arranged to face away from the receiving fitting when the compression ring is arranged within the receiving fitting, the compression fitting further comprising a union nut configured for attachment with the receiving fitting and having a second compression surface configured, when the union nut is attached with the receiving fitting, to engage the first compression surface of the compression ring and cause the compression ring to move radially inwardly for gripping the conduit, the invention residences in that the compression ring and the receiving fitting comprise a securing means for securing the compression ring within the receiving fitting. This ensures that the compression ring cannot fall out of the receiving fitting during assembly or disassembly. The securing means may comprise a frictional connection, an adhesive connection or an interlock connection, for instance.

In tightening the compression fitting, the second compression surface of the union nut will abut against the first compression surface of the compression ring. Ideally, the compression fitting is configured such that the second compression surface slides over the first compression surface during tightening. For this reason, it can be advantageous if the first and second compression surfaces are smooth at least in the region where they abut against each other. To ensure an even distribution of force, it may be favorable if the first compression surface and/or the second compression surface extend in the circumferential direction, preferably around the entire circumferential direction. In one embodiment, the second compression surface is formed on a radially inner surface of the union nut and the first compression surface is formed on a radially outer surface of the compression ring.

The internal cavity may have a form at least similar or identical to a conduit to be inserted. For instance, the internal cavity may have a circular cross-section and comprise a cylindrical space, if a cylindrical conduit is to be used. In some embodiments, the internal cavity may comprise a stop element within it to prevent a conduit from being inserted too far.

Preferably, the securing means comprises a first element at a radially outer surface of the compression ring and a second element at a radially inner surface of the receiving fitting. This ensures that the first element and the second element are in close contact and reduces the amount of machining necessary or size of extra components that need to be attached. It also ensures that the securing means is within the body of the compression ring and thereby well protected from damage or interference.

In a particularly advantageous embodiment, the first element comprises at least one protrusion and the second element comprises a lip. These elements can thus work together to form an interlock connection, in particular in such a way that the connection is formed when the compression ring is pushing into the receiving fitting, in that the protrusion is forced over the lip. It is therefore helpful when at least one of the compression ring and/or the receiving fitting comprises a somewhat flexible material, which is able to flex under the pushing force under conditions of normal use. This also has the advantage that it is not easy for the compression ring to escape from the receiving fitting without a substantial force being applied.

In a further development, the second element comprises a stop surface behind the lip in a direction towards the internal cavity, and an indentation arranged between the lip and the stop surface. The presence of the indentation provides a space for the protrusion to be accommodated, which provides further security against the parts detaching from each other. The stop surface may be a surface against which the compression ring abuts after insertion of the compression ring into the receiving fitting. The stop surface may help in ensuring that the compression ring reaches the correct position to allow the protrusion to be located it its correct or optimum position. The indentation may have a profile which exactly matches the outer profile of the protrusion. Alternatively, the indentation may have chamfers or inclined edges to allow the protrusion to slide in and out of it upon insertion or retraction of the compression ring into or out of the receiving fitting.

Preferably, the lip extends around the entire inner circumference of the receiving fitting. This simplifies manufacturing and ensures that there are no spaces in the circumferential direction that may allow the compression ring to slip out of the receiving fitting.

A further favorable embodiment provides that the indentation extends around the entire inner circumference of the receiving fitting. This ensures that the protrusion finds an engagement location regardless of the rotational orientation with which the compression ring is inserted into the receiving fitting.

It is thinkable that the protrusion extends all the way around an outer surface of the compression ring. In this way, force is applied over a wider region of the compression ring when the compression ring is inserted into the receiving fitting, which further reduces stress. This also ensures that a securing force is maximized, since engagement of the compression ring with the receiving fitting occurs around more of the outer surface of the compression ring.

Advantageously, the lip and/or the indentation comprises a chamfered surface. This can assist in guiding the protrusion and thereby the compression ring into the receiving fitting. In particular, the chamfered surface may be configured and located so that the protrusion is guided on insertion of the compression ring into the receiving fitting, or so that the protrusion is guided on removal of the compression ring from the receiving fitting, or both.

In particular, the chamfered surface or surfaces may be configured and located to allow the compression ring to be removed from the receiving fitting only by application of a force along the longitudinal axis. This may be contrasted with having to apply a radial force to the compression ring to remove the protrusion from the indentation or bring it over the lip.

In another aspect, the receiving fitting comprises a chamfered surface for guiding the first element, for instance the protrusion, towards the second element, for instance over the lip, upon insertion of the compression ring into the receiving fitting.

In order to further aid movement of the protrusion and minimize stress or wear, the protrusion may comprise a chamfered surface. The chamfered surface may be arranged at a side facing towards the first longitudinal end of the compression ring, at a side facing towards the second longitudinal end of the compression ring, or both. This reduces the presence of sharp edges or corners which may increase wear when the protrusion (i.e. the compression ring) is inserted or removed from the receiving fitting.

In a very favorable example of the invention, side walls of the compression ring comprise longitudinal openings. This allows the compression ring to flex in the radial direction more easily. The openings may be arranged and located to extend from substantially the first longitudinal end to substantially the second longitudinal end of the compression ring. In this way, flexion is permitted over a greater region. The openings may also be located next to each other in the circumferential direction of the compression ring. This ensures that flexion may occur around most or all of the side walls of the compression ring.

In particular, the compression ring may comprise longitudinal openings that extend substantially from the region of the first end all the way to the second end, whereby said openings are distributed around the circumference of the compression ring. This results in the provision of distinct legs that are able to flex backwards and forwards. In this embodiment, the compression ring may also comprise a plurality of first compression surfaces, if the longitudinal openings also extend in the same region as the first compression surface.

A favorable embodiment may provide that the openings in the compression ring are wider at the end of the compression ring than in the body of the compression ring. In particular, the openings may be substantially fan-shaped. This creates more space in the region of the end of the compression ring and allows the ends of the legs of the compression ring to flex a greater distance without colliding with and blocking each other.

A further favorable design foresees that the compression ring comprises a plurality of legs, whereby each leg comprises a first compression surface. In this way, each compression surface may cause each leg of the compression ring to move radially inwardly to grip a conduit.

Preferably, the compression ring comprises a stop wall, which may mate with a bearing region of the union nut. In this way, the bearing region of the union nut may bear against the stop wall. The bearing action of the union nut may urge the compression ring against a sealing ring during tightening of the connection, for instance, thereby improving the seal.

Ideally, in the region of an opening of the receiving fitting (that is, an opening facing along the longitudinal axis) , the receiving fitting comprises a chamfered surface for guiding the protrusion of the compression ring into the indentation and over the lip upon insertion of the compression ring. Further, the protrusion may comprise a chamfer at a surface facing towards the first end of the compression ring, which provides a larger surface area to distribute the force that is applied when the compression ring is inserted into or removed from the receiving fitting. In particular, no corners or edges may be present which would experience a much higher pressure when the compression ring is inserted or removed. This could lead to cracking or failure in the region of the protrusion.

In some embodiments, the union nut may be configured to facilitate use of a spanner to rotate it. In particular, the union nut may comprise a plurality of flat surfaces on its radial outer surface that permit a spanner to engage with it.

In another embodiment, the first longitudinal end of the compression ring has an end surface and the receiving fitting has an end wall within the internal cavity, and a sealing ring is arranged, preferably arranged to be compressed, between the end surface and the end wall. In this configuration, the sealing ring may be compressed between the receiving fitting and the compression ring when the latter is inserted into the receiving fitting, which aids in preventing media from escaping from the compression fitting.

The sealing ring may have a shape complementary to the region of the receiving fitting in which the sealing ring is received, so as to ensure a good sealing contact between the sealing ring and the receiving fitting. The sealing ring may also have a shape complementary to an end surface of the compression ring, so as to ensure a good sealing contact between the compression ring and the sealing ring. In one embodiment, the sealing ring comprises a square or rectangular cross section. The sealing ring may also have a protrusion facing into an internal cavity of the compression fitting, which may bear against an inserted conduit, so as to improve a sealing action.

In a further embodiment, the internal cavity of the receiving fitting comprises a circumferential recess for receiving the compression ring. The circumferential recess then acts to specifically and effectively accommodate and secure the compression ring and the sealing ring within the receiving fitting.

Preferably, both the end surface and the end wall of the circumferential recess are arranged to be substantially or exactly perpendicular to the longitudinal direction. This ensures that the entire sealing ring is not forced radially inwardly or substantially relocated when it is compressed between the end wall and the end surface. It also encourages even compression of the sealing ring.

The end surface of the compression ring may comprise the outer surface of an opening at the first end of the compression ring, the first end being the end inserted into the receiving fitting and the second end being the end that faces out of the receiving fitting.

The sealing ring may be configured in cooperation with the compression fitting for compression against an inserted conduit when the union nut is engaged with the receiving fitting, for example tightened onto the receiving fitting. In particular, the compression fitting may be configured such that tightening or engaging of the union nut causes movement of the compression ring in the longitudinal direction, so that the sealing ring is increasingly compressed between the end surface of the compression ring and the end wall of the circumferential recess.

In another advantageous design, the compression ring comprises tooth-like members at a radially inner surface of the second longitudinal end that extend along the radial axis. These may then more effectively grip an inserted conduit when the compression ring is caused to move radially inwardly.

In a highly preferred design, the first and second compression surfaces are sloped with respect to the longitudinal axis. This provides a very effect way of creating radial compressive force through motion of the compression ring along the longitudinal axis. The slope angle should be greater than 0 degrees up to around 50 degrees with respect to the longitudinal axis. More preferably is an angle of up to around 30 degrees with respect to the longitudinal axis.

In a further embodiment, the receiving fitting comprises a first engagement section and the union nut comprises a second engagement section, whereby the first engagement section and the second engagement section are configured to cooperate to attach the union nut to the receiving fitting. In this way, the movement may be more easily achieved to cause the compression ring to move radially inward to grip an inserted conduit.

Preferably, the first engagement section and the second engagement section engage via screw threads. In this way, the union nut may simply be screwed onto the receiving fitting. However, it is also thinkable that the first engagement section and second engagement section comprise a series of snap-in elements that allow engagement of the first and second engagement sections only by movement along the longitudinal axis without rotation. Alternatively, a latch-type mechanism could be used that allows a user to push the union nut and the receiving fitting together to a sufficient tightness, and then secure them together via the latch.

In an advantageous embodiment, the first engagement section is arranged on a radially outer surface of the receiving fitting and the second engagement section is arranged on a radially inner surface of the union nut. In this way, the union nut can enclose all parts.

The invention further provides a compression fitting comprising two previously described compression fittings arranged back to back for accommodating two conduits and wherein the respective internal cavities are joined to form one continuous internal cavity. In this way, two separate conduits may be joined together.

Brief Description of the Drawings

Further features, details and advantages of the invention arise from the wording of the claims as well as from the following description of embodiments with the help of the figures. These show:

Fig. 1 a perspective view of an assembled compression fitting;

Fig. 2 an exploded view of a compression fitting;

Fig. 3 a cross-sectional view of an assembled compression fitting; and

Fig. 4 a detailed view of the securing means of the compression fitting.

Detailed Description

The compression fitting 1 of Fig. 1 is shown in an assembled state. A union nut 30 is screwed onto a receiving fitting 5. A compression ring 20 is held inside the compression fitting 1 (i.e. inside the receiving fitting 5) and may be partly seen through the opening of union nut 5. A conduit is not shown inserted into the compression fitting 1.

Fig. 2 shows an exploded view of the inventive compression fitting 1, which has two compression fittings arranged back to back and joined via a middle section. In the following, only one side of the compression fitting will be described, it being understood that the description also relates to the other compression fitting. A receiving fitting 5 comprises a threaded first engagement section 6. Sealing ring 50 is positioned between a longitudinal end of the receiving fitting 5 and a first longitudinal end 22 of a compression ring 20. The compression ring 20 has several longitudinal openings 27 (two visible) which extend from a region of a first longitudinal end 22 all the way to a second longitudinal end 23 of the compression ring 20, resulting in the formation of legs 70 (three visible) . First compression surfaces 21 are arranged on a radially outer surface 24 of the compression ring 20 in a region of the second longitudinal end 23. In particular, the first compression surfaces are arranged on the radially outer surfaces 24 of the legs 70, each leg 70 having a first compression surface 21. Also visible are several first elements 41 (forming part of securing means 40) , which in this case are embodied as several protrusions 43 that extend outwards in the radial direction R from a radially outer surface 24 of the compression ring 20. Union nut 30 is also shown.

A cross-section of the assembled compression fitting 1 (without an inserted conduit) is shown by Figs. 3 and Fig. 4. Union nut 30 is shown screwed onto the receiving fitting 5 by means of second engagement section 31 (formed as a thread) of union nut 30 engaging with first engagement section 6 (also formed as a thread) of the receiving fitting 5. The second engagement section 31 is formed on a radially inner surface 33 of the union nut 30 and the first engagement section 6 is formed on a radially outer surface 10 of the receiving fitting 5.

A second compression surface 32 also formed on a radially inner surface 33 of the union nut 30 bears against a first compression surface 21 of the compression ring 20 held in the receiving fitting 5. The second compression surface 32 acts to deform the compression ring 20 inwardly along the radial axis R, so that the compression ring 20 could bear against and thereby secure a conduit inserted in the compression fitting 1.

To facilitate this, compression ring 20 has legs 70 that extend from a region of a first longitudinal end 22 of the compression ring 20 all the way to a second longitudinal end 23 of the compression ring 20. The legs 70 are able to flex radially inwardly and outwardly. The legs 70 also have tooth-like members 26 formed on their radially inner surface 25 which are able to grip and bite into an inserted conduit. In the present embodiment, the tooth-like members 26 are formed as rows on each leg 70.

The compression ring 20 is received in a circumferential recess 11 of the receiving fitting 5, which extends in the circumferential direction A, such that the first longitudinal end 22 of the compression ring 20 extends into the circumferential recess 11. An end surface 29 of the first longitudinal end 22 contacts and compresses a sealing ring 50, which is held between an end wall 12 of the circumferential recess 11 and the end surface 29 of the compression ring 20. The recess has a chamfered surface 62a to ensure smooth insertion and removal of the compression ring.

Union nut 30 has a bearing region 34, which bears against a stop wall 28 of the compression ring 20 when the union nut 30 is urged towards the compression ring 20.

Securing means 40 is formed by a first element 41 on a radially outer surface 24 of the compression ring 20 that interacts with a second element 42 on a radially inner surface 8 of the receiving fitting 5. First element 41 is formed as a protrusion 43. In particular, each leg 70 of the compression ring 20 has a protrusion 24 associated with it. The protrusion 24 has a chamfered surface 62c that facilitates a smoother insertion of the compression ring 20 into the receiving fitting 5 past the second element 42, a circumferential lip 60 in a region of an opening 2 of the compression fitting 1 formed in the receiving fitting 5. The lip 60 has an inclined region 64, i.e. a chamfered surface 62b, that increases in height in the direction of the inside of the internal cavity 7, such that the diameter of the receiving fitting 5 becomes smaller.

The lip 60 comprises a flat section 63 which is parallel to the longitudinal axis L. The flat section 63 is followed by (in the direction of the internal cavity 7) a declined region 65 that leads to an indentation 61, whereby the diameter of the receiving fitting 5 is larger in the region of the indentation 61 than in the region of the flat section 63.

The indentation 61 is followed by a stop surface 13, which is perpendicular to the longitudinal axis L and extends inwardly along the radial axis R. The stop surface is followed by the circumferential recess 11, which runs parallel to the longitudinal axis L. The circumferential recess 11 has an end wall 12, which extends perpendicular to the longitudinal axis L and inwardly along the radial axis R. The diameter of the receiving fitting 5 is smaller in the region of the circumferential recess 11 than in the region of the indentation 61 or in the region of the flat section 63.

The invention is not restricted to one of the previously described embodiments but rather may be varied in a number of ways. All features and advantages arising from the claims, the description and the figures, including constructional details, spatial arrangements and method steps, can be significant for the invention alone as well as in various combinations.

List of References

1 Compression fitting 34 Bearing region

2 Opening

40 Securing means

5 Receiving fitting 41 First element

6 First engagement section 42 Second element

7 Internal cavity 43 Protrusion

8 Radially inner surface

9 Inner circumference 50 Sealing ring

10 Radially outer surface

11 Circumferential recess 60 Lip

12 End wall 61 Indentation

13 Stop surface 62a Chamfered surface

62a Chamfered surface

L Longitudinal axis 62c Chamfered surface

R Radial axis 63 Flat section

A Circumferential direction 64 Inclined region

65 Declined region

20 Compression ring

21 First compression surface 70 Leg

22 First longitudinal end 71 Side wall

23 Second longitudinal end

24 Radially outer surface

25 Radially inner surface

26 Tooth-like member

27 Longitudinal opening

28 Stop wall

29 End surface

30 Union nut

31 Second engagement section

32 Second compression surface

33 Radially inner surface

Claims

A compression fitting (1) comprising:

a receiving fitting (5) having an internal cavity (7) extending along a longitudinal axis (L) of the receiving fitting (5) for accommodating a conduit, and having a radial axis (R) perpendicular to the longitudinal axis (L) ,

a compression ring (20) configured to be arranged at least partly within the receiving fitting (5) and having a first compression surface (21) , the compression ring (20) comprising a first longitudinal end (22) arranged to face towards the receiving fitting (5) and a second longitudinal end (23) arranged to face away from the receiving fitting (5) when the compression ring (20) is arranged within the receiving fitting (5) ,

a union nut (30) configured for attachment with the receiving fitting (5) and having a second compression surface (32) configured, when the union nut (30) is attached with the receiving fitting (5) , to engage the first compression surface (21) of the compression ring (20) and cause the compression ring (20) to move radially inwardly for gripping the conduit, characterized in that the compression ring (20) and the receiving fitting (5) comprise a securing means (40) for securing the compression ring (20) within the receiving fitting (5) .
The compression fitting (1) of claim 1, characterized in that the securing means (40) comprises a first element (41) at a radially outer surface (24) of the compression ring (20) and a second element (42) at a radially inner surface (8) of the receiving fitting (5) .
The compression fitting (1) of claim 2, characterized in that the first element (41) comprises at least one protrusion (43) and the second element (42) comprises a lip (60) .
The compression fitting (1) of claim 2 or 3, characterized in that the second element (42) comprises a stop surface (13) behind the lip (60) in a direction towards the internal cavity (7) , and an indentation (61) arranged between the lip (60) and the stop surface (13) .
The compression fitting (1) of claim 3 or 4, characterized in that the lip (60) and/or the indentation (61) extends around the entire inner circumference (9) of the receiving fitting (5) .
The compression fitting (1) of one of claims 3 to 5, characterized in that the lip (60) or the indentation (61) comprises a chamfered surface (62) .
The compression fitting (1) of one of the preceding claims, characterized in that side walls (71) of the compression ring (20) comprise longitudinal openings (27) .
The compression fitting (1) of one of claims 3 to 7, characterized in that the protrusion (43) comprises a chamfered surface (62) .
The compression fitting (1) of one of the preceding claims, characterized in that the first longitudinal end (22) of the compression ring (20) has an end surface (29) and that the receiving fitting has an end wall (12) within the internal cavity (7) , and a sealing ring (50) is arranged between the end surface (29) and the end wall (12) .
The compression fitting (1) of one of the preceding claims, characterized in that the internal cavity (7) of the receiving fitting (5) comprises a circumferential recess (11) for receiving the compression ring (20) .
The compression fitting (1) of one of the preceding claims, characterized in that the compression ring (20) comprises tooth-like members (26) at a radially inner surface (25) of the second longitudinal end (23) that extend along the radial axis (R) .
The compression fitting (1) of one of the preceding claims, characterized in that the receiving fitting (5) comprises a first engagement section (6) and the union nut (30) comprises a second engagement section (31) , whereby the first engagement section (6) and the second engagement section (31) are configured to cooperate to attach the union nut (30) to the receiving fitting (5) .
The compression fitting (1) of one of the preceding claims, characterized in that the compression ring (20) comprises a plurality of legs (70) , whereby each leg comprises a first compression surface (21) .
A compression fitting (1) comprising two compression fittings (1) according to one of the preceding claims arranged back to back for accommodating two conduits and wherein the respective internal cavities (7) are joined to form one continuous internal cavity (7) .