GB2072780A

GB2072780A - Connector fitting for the quick and releasable connection of synthetic piping

Info

Publication number: GB2072780A
Application number: GB8108782A
Authority: GB
Original assignee: Armaturenfabrik Hermann Voss GmbH and Co
Current assignee: Voss Automotive GmbH
Priority date: 1980-03-25
Filing date: 1981-03-20
Publication date: 1981-10-07
Also published as: IT1170841B; GB2072780B; FR2479407B3; FR2479407A1; IT8148096A0; DE3011430A1; DE3011430C2

Abstract

A connector fitting for the quick and releasable connection of synthetic piping comprises a housing 1 for receiving the end of the pipe 16, the housing consisting of a threaded pipe 3 and a clamping nut 2 in screw- threaded engagement with one another. A clamping ring 7 is arranged within the clamping nut 2 and has a number of internal cutting edges 9 for cutting into the end of the pipe and an outer frusto-conical surface 8a which cooperates with an inner frusto- conical surface 12 on the clamping nut. O-ring seals 15, 23 are provided between the clamping nut and the synthetic pipe and between the clamping nut and the threaded pipe 3. <IMAGE>

Description

SPECIFICATION Connector fitting for the quick and releasable connection of synthetic piping This invention relates to a connector fitting, for the quick and releasable connection of synthetic 'piping, of the kind comprising a housing for receiving the end of the pipe, a compression element arranged within the housing and having at least one cutting edge for cutting into the end of the pipe and an outer frusto-conical surface which cooperates with an inner frusto-conical surface on the housing, and a peripheral seal within the housing.

One type of connector fitting known, for example, from German Offenlegungsschrift No. 28 07 508 consists of five component parts, including a housing and a separate connecting piece. On assembly, the housing resiliently engages in an annular groove in the connecting piece, a support ring forming a chamber for receiving a sealing ring. This type of connector fitting has the disadvantage that the connecting piece is a special part and, moreover, it is not possible, for example, to connect valve housings directly into the boreholes of the housing.

Furthermore, owing to the fact that the housing resiliently engages the connecting piece, it is not possible to adjust the clamping pressure by which the pipe to be connected is held.

The object of the present invention is to produce a connector fitting which can be used in conjunction with standard parts and which can be released by using customary tools, and which is also distinguished by a simple and sturdy method of construction with high resistance to wear, according to the requirements of the motor vehicle industry. According to the invention, this is achieved in that the housing consists of two parts in screw-threaded engagement with one another.

By this means, one part of the housing can be in the form of a threaded pipe and the other part in the form of a clamping nut which can be screwed onto the threaded pipe. Of course, it is also possible for one housing part to be formed directly by a valve housing which has a borehole with an internal thread, into which the other housing part in the form of a cap screw can be screwed.

However, the borehole with an internal thread can also be part of an adapter which is screwed into a valve housing. A connector fitting formed in such a way makes it possible for it to be fitted onto any connection with a frusto-conical surface conforming to the German Industrial Standards.

For this means, in one embodiment of the invention, it is simply necessary to provide a clamping nut and an appropriately formed clamping ring. After pulling an O-ring over the threaded connection of the connecting piece, the positioning of the clamping ring and screwing in of the new clamping nut, a one-layer synthetic pipe, for example, can be inserted into the fitting with or without a supporting casing as far as the stop of the connecting piece. During the insertion process, the clamping ring expands and allows the synthetic pipe to slide through and is subsequently clamped onto the latter.If force is applied to the connector to attempt to strip it from the pipe, the frusto-conical surface of the clamping ring engages against the corresponding inner frustoconical surface of the clamping nut, and the inner cutting edge of the clamping ring penetrates into the synthetic pipe. Therefore it is particularly suitable if the sealing O-ring is arranged in the upper area of the clamping nut or cap screw, through which the synthetic pipe is inserted into the connection, since thereby the fluid tightness of the fitting is not affected by damage to the end of the piping, which can be caused, for example, by the cutting edge of the clamping ring.

The following is a detailed description of embodiments of the invention, reference being made to the accompanying drawings in which: Figures 1 and 2 show two alternative forms of a connector fitting according to the invention, partly in section, Figure 3 is a part section through a compression element used in the embodiment shown in Figures 1 and 2, Figures 4 to 6 show alternative forms of a connector fitting according to the invention, partly in section, with a cap screw, Figure 7 is a view of a compression element used in the embodiment of Figure 6, Figure 8 is a section along the line VIll-Vill of Figure 7, Figure 9 shows a further form of a connector fitting according to the invention, partly in section, with a cap screw, Figure 10 shows a further form of a connector fitting according to the invention with a clamping nut, partly in section, Figure 1 1 shows a further alternative form of a connector fitting according to the invention with a clamping nut, Figure 12 is a view of the compression element used in the connector fitting of Figure 11, and Figure 13 is a section along the line Xlll-Xlll of Figure 12.

In Figure 1 there is shown a connector fitting according to the invention. This consists of a housing 1 which comprises two threadedly engaged parts: a clamping nut 2 and a threaded pipe 3. The threaded pipe 3 consists of a connecting piece 4 which can also be threaded and a connecting piece 5 with an external thread 6 which engages the internal thread of the clamping nut. The clamping nut 2 is screwed onto the connecting piece 5. A compression element in the form of a clamping ring 7 is disposed within the clamping nut 2. The clamping ring 7 has a first portion 8, the outer surface 8a of which is frustoconical, and, in the example shown, the inner surface of which is formed with three cutting edges 9.A centre section 10 is connected to the first portion, this centre section having a smaller wall thickness than the first portion 8. An end portion 1 1 is connected to the centre section 10, this end portion being formed with an internal flange. The frusto-conical outer surface 8a of the first portion 8 cooperates with a corresponding frusto-conical inner surface 12 on the clamping nut 2. Adjacent the smaller diameter end of the surface 12 is a cylindrical surface 13 having an inner groove 14 in which an O-ring 15 is located to act as a flexible sealing ring. The diameter of the surface 13 conforms to the outer diameter of a synthetic pipe 16 to be inserted into it, so that this can be sealed by the O-ring.A cylindrical guide surface 17 on the clamping nut is adjacent the larger diameter end of the surface 12, the inner diameter of the surface 17 corresponding approximately to the outer diameter of the pipe 16 plus twice the thickness of the wall of the clamping ring 7. The connecting piece 5 has a central opening 18 which becomes wider towards the open end thereof. The threaded pipe 3 conforms to a standard German Industrial Standards connecting piece, so that the connector fitting according to the invention can consist partly of standard components, so that universal application can be achieved at relatively low manufacturing cost. At the inner end of the opening 18 inside the threaded pipe 3 there is a recess 19 into which the through-bore 20 of the pipe opens and which serves as a stop for the end of the pipe 16.The through-bore 20 has an inner diameter which corresponds to that of the synthetic pipe 16. A supporting casing 21, preferably of metal, is inserted into the end of the synthetic pipe, this being used to support the pipe.

The end of the supporting casing 21 which projects from the pipe is provided with an external flange 22 which is compressed when the pipe is inserted and when subsequently the connection between the end of the pipe and the recess 19 is tightened. The threaded portions of the pipe 3 and clamping nut 2 are sealed externally by an O-ring 23 arranged in a rebate 24 at the rear end of the nut 2. By means of an inclined surface 25 on the clamping nut 2, compression of the O-ring 23 is effected when the clamping nut is tightened.

In Figure 1, the connector fitting according to the invention is shown in a tightened condition.

On assembly, the pipe with an inserted supporting casing 21, is inserted into the previously assembled housing 1 with a ready-assembled, tightened clamping nut 2. Due to the flexible formation of the clamping ring 7, the pipe can be pushed through the cutting edges 9 as far as the recess 19. By means of the clamping action of the spring arms of the clamping ring 7, see Figure 3, the cutting edges 9 cut into the soft synthetic pipe and hold it securely. 15 the pipe is pulled, or internal pressure is exerted, it attempts to move out of the housing, the clamping ring 7 being carried along with it. Due to the cooperating action of the two frusto-conical surfaces 8a and 12 which thereby occurs, the holding action of the clamping ring is increased.Since the sealing O-ring 15 is provided in the screwing up direction in front of the clamping ring 7, the advantage is obtained that any damage to the pipe caused by the cutting edges 9 during insertion, or during subsequent withdrawal in the case of the connector fitting becoming loose, cannot affect the fluid-tightness of sealing. The connector fitting according to the invention can always be released and can be reused. For this purpose, of course, the clamping nut 2 must be unscrewed from the threaded pipe 3. Then the clamping nut and clamping ring can be removed from the pipe, which is essentially achieved due to the flexibility of the clamping ring, which can be seen in detail in Figure 3, and due to the small cutter depth arid special arrangement of the O-ring 1 5.

A further embodiment of a connector fitting according to the invention is shown in Figure 2.

Here, the same components as are shown in Figure 1 are given the same reference numerals.

This connector fitting, in contrast to that shown in Figure 1, is characterised by a shorter overall length. This has the result that the clamping ring 7 is arranged partly inside the clamping nut 2 and partly inside the threaded pipe 3. The guide surface 17 of the embodiment according to Figure 1 is omitted. Moreover, the inner thread of the clamping nut 2 is immediately adjacent the frusto-conical surface 12. The connecting piece 5 has a cylindrical opening 25a in which the centre section 10 and end portion 1 1 of the clamping ring 7 are held, whereby the end portion 11 of the clamping ring abuts against a shoulder 26 in the opening 25.A counter-bored section 27 of the through-bore 20 connects with the opening 25a, the diameter of the counter-bore corresponding to the outer diameter of the pipe 1 6. so that this can lie against the recess 19 as an end stop. In this example, the end of the supporting casing 21 is not formed with a flange, but is compressed into the through-bore 20. Thereby the previous assembly of the supporting casing on the pipe is unnecessary.

In Figure 3, the clamping ring 7 is shown. Here it can be seen that the inner diameter of the end portion 11 is larger than the inner diameter of the cutting edges 9, which is smaller than the outer diameter of the pipe 16. The clamping ring has two or more elongate slots 28 distributed around its circumference, which slots extend from a closed annular area 29, which is provided by the end portion 11, to the opposite end. The opening in the first portion 8 of the ring widens towards the mouth of the opening, so that the pipe 1 6 can easily be fed into the clamping ring. Due to the elongate slots 28 in conjunction with the reduction in wall thickness of the centre section, spring arms are formed on the clamping ring 7, whereby radial flexibility of the clamping ring 7 is achieved, particularly in the area of its cutting edges 9. The clamping ring can be made of a synthetic or metallic material, preferably brass.

In Figure 4, a further alternative embodiment of a connector fitting according to the invention is shown. This connector fitting has a clamping ring 7 which corresponds to those in the embodiments in Figures 1 to 3. The connector fitting shown comprises a housing section 31 which can be formed by a valve housing or something similar.

The housing section might, for example, be a section of an adapter. This housing section 31 has a tapped hole 32 into which the other threaded section, a cap screw 33, is screwed. The clamping ring 7, with its first portion 8 and its centre section 10, is arranged inside the cap screw. By this means the outer frusto-conical surface 8a of the first portion 8 cooperates with an inner frustoconical surface 34 of the cap screw 33. The centre section 10 is disposed within a bore section 35 adjacent the frusto-conical surface 34. The end portion 11 of the clamping ring 7 projects out of the cap screw 33, and the clamping ring can be supported on the shoulder 36 at the inner end of the tapped hole 32 when the pipe 16 is inserted.

The larger diameter of the frusto-conical surface 34 and of the bore section 35 corresponds to the larger diameter of the surface 8a or of the centre section 10. The head 37 of the cap screw engages the outer wall surface 38 of the housing section 31. The head 37 has a bore section 39, the diameter of which conforms to the outer diameter of the pipe 1 6. In the bore section 39 there is forming an internal groove 40 containing an O-sealing ring 41. Where the head 37 meets the external threaded portion 42 a groove 43 is provided, in which an O-ring 44 is inserted for sealing the threaded section. The end of the pipe 16 lies inside a bore section which is connected to the tapped hole 32 and which has a diameter conforming to the outer diameter of the pipe 16.

Thereby the end of the pipe rests on a shoulder 46. The end of the pipe is also pushed onto a metal supporting casing 47, which is compressed against a shoulder 49 in the bore section 50. By this arrangement of the supporting casing, the end of the pipe and the clamping ring, a type of labyrinth seal is formed. As already described in the embodiment according to Figures 1 and 2, the O-sealing ring is so arranged in relation to the clamping ring that any damage caused to the outer surface of the pipe by the clamping ring will not affect the sealing action of the O-ring.Also, this embodiment of the connector fitting is preassembled, that is, the supporting casing is compressed into an enlarged portion of the bore section 50 of the housing section 31 and the cap screw 33 is tightly screwed up, so that, to assemble the pipe, it is only necessary to insert it into the housing as far as the shoulder 46.

Jn Figure 5 there is shown a connector fitting which differs from the embodiment shown in Figure 4, the components which are the same as those in Figure 4 being given the same reference numerals. The main difference in this embodiment is in the shape of the clamping ring 51 and the internal shape of the cap screw 33.The clamping ring 51 has a first portion 52 with an outer frustoconical surface 53 and preferably at least two cutting edges 9 on the inner surface thereof.

Approximately aligned with the middle of the first portion, in the radial direction, is a centre section 54 having a reduced wall thickness, which ends in a flange-like radial end portion 55 bent outwards, with an increased wall thickness. The end portion 55 forms a closed ring, from which slots extend to the opposite end of the clamping ring, so that the desired radial flexibility is achieved, as with the clamping ring 7 in the previously described embodiment. The end portion 56 of the clamping ring 51 rests on the shoulder 36 at the bottom of the tapped hole 32. The outer frusto-conical surface 53 of the clamping ring cooperates with the inner frusto-conical surface 34 of the cap screw 33, the surface 34 extending to the end of the cap screw.The bore section 56 of the screw head 37 also has a sealing O-ring 41 in an annular groove 40, but in this case the bore section 56 extends further axially than is the case in the Figure 4 embodiment, having a diameter conforming to the outer diameter of the pipe 1 6.

The sealing of the screw threads is achieved as in the embodiment according to Figure 4. A supporting casing 57 is inserted into the end of the pipe, this casing having an external flange 58 against which the end of the pipe rests, the flange 58 resting on a shoulder 59 in a bore section 60 leading to the through-bore 50. The diameter of the bore section 60 corresponds to the outer diameter of the flange 58 and to the diameter of the pipe 16. The embodiment according to Figure 5 has an increased overall length compared to that of Figure 4 due to the reduced diameter of the cap screw, whereby the internal shape of the cap screw is simplified.

In Figure 6 a further example of a connector fitting according to the invention with a cap screw is shown. This differs principally from those in Figures 4 and 5 in the formation of the clamping ring 62. In contrast to the clamping rings 7 and 51, the clamping ring 62 has a tapered section providing an outer frusto-conical surface 63 and having only one inner cutting edge 9. The configuration of the clamping ring 62 is shown in greater detail in Figures 7 and 8. The clamping ring has a slot 64. in order to achieve adequate radial flexibility, it is made either of a thermoplastic synthetic material or of spring steel.

The inner contour of the borehole of the housing section 31 corresponds essentially to that of the embodiment according to Figure 4, and the same applies to the configuration of the supporting casing 47. On the other hand, the cap screw 37 corresponds to that of the embodiment according to Figure 5. Instead of an O-ring, a lip seal 67 is arranged in the bore section 56 in a groove 66, for sealing purposes.

In Figure 9 a further embodiment of a connector fitting according to the invention is shown, this being based on the embodiment according to Figure 6. However, as distinct from the arrangement of Figure 7 and Figure 8, the clamping ring 62 has three inner cutting teeth. In this embodiment, the O-ring 70 is not housed in a groove in the cap screw but is positioned at the end of the cap screw and is held by a support ring 72 arranged in front of it. This support ring 72 has an inner frusto-conical surface 73 which cooperates with the outer frusto-conical surface 63 on the clamping ring 62.This formation produces the advantage that when pressure is applied, the sealing ring 70 is pressed over the clamping ring 62 and the support ring, in addition to being pressed against the pipe, whereby the sealing action is improved, and also the expensive forming of a groove in the cap screw can be dispensed with, as the cap screw can be constructed as a whole as a simple hollow screw.

Furthermore, a separate thread sealing arrangement is not necessary.

In Figure 10, the sealing and compressing principle of the clamping ring and support ring of Figure 9 is applied to a connector fitting with a clamping nut according to Figure 2. In this arrangement the clamping ring 63 and support ring 72 are of the form shown in Figure 9.

Components which are the same as those in Figure 2 are given the same reference numerals.

Of course, as before, in this embodiment it is appropriate to seal the threaded area. The supporting casing 81 is integral with the connecting piece, and surrounding the connecting piece is an annular space 82 which receives the end of the pipe.

In Figure 11 a further alternative embodiment of a connector fitting according to the invention is shown. As with the embodiment according to Figure 1, this consists of a clamping nut 2 and a threaded pipe 3. However, it embodies another form of sealing in conjunction with a modified compression element. The O-ring 75 is engaged on one side by the connecting piece 5 and on the other side by a compression element in the form of a clamping ring 76. The clamping ring 76 is shown in detail in Figures 12 and 13. In this case the clamping ring 76 has three cutting edges 9 and an outer frusto-conical surface 77 which cooperates with the inner surface 78 of the clamping nut 2. So as to facilitate insertion of the pipe 16, the clamping ring has an insertion opening 79 which widens outwards and a sloping contact surface 80 for the sealing ring 75 (see Figure 13). It has a slot 87, so as to provide two spring arms in conjunction with an opposite outer flat surface 88, whereby radial flexibility is obtained. The ring can be made from a flexible synthetic material or from metallic material, preferably brass. The thread area is in addition sealed externally, as in Figure 2.

Claims

1. A connector fitting for the quick and releasable connection of synthetic piping, comprising a housing for receiving the end of the pipe, a compression element arranged within the housing and having at least one cutting edge for cutting into the end of the pipe and an outer frusto-conical surface which cooperates with an innerfrusto-conical surface on the housing, and a peripheral seal within the housing, the housing consisting of two parts in screw-threaded engagement with one another.

2. A connector fitting according to claim 1, wherein one part of the housing is in the form of a threaded pipe and the other part is in the form of a clamping nut.

3. A connector fitting according to claim 1, wherein one part of the housing has a tapped hole with an internal thread, into which the other part housing, which is in the form of a cap screw, can be screwed.

4. A connector fitting according to cairn 2 or claim 3, wherein the peripheral seal is arranged within the clamping nut or cap screw and in front of the compression element.

5. A connector fitting according to any one of claims 1 to 4, wherein a supporting casing is provided for insertion into the end of the pipe.

6. A connector fitting according to any one of claims 1 to 5, wherein the compression element is in the form of a clamping ring with at least one inner cutting edge.

7. A connector fitting according to claim 6, wherein the clamping ring has a centre section of reduced wall thickness which, in the screwing up direction, connects a first portion, provided with said outer frusto-conical surface and a cutting edge, with an end portion in the form of a flange.

8. A connector fitting according to claim 6 or claim 7, wherein the clamping ring has distributed around its circumference at least two axially extending elongate slots issuing from a closed ring portion.

9. A connector fitting according to claim 6 or claim 7, wherein the clamping ring has an outer frusto-conical surface and an inner cutting edge and an elongate slot, the latter being opposite a flattened area of the ring.

10. A connector fitting according to any one of claims 1 to 9, wherein the peripheral seal is in the form of a lipped sealing ring.

11. A connector fitting according to any one of claims 1 to 10, wherein a supporting casing for the end of the pipe is pressed into the housing.

1 2. A connector fitting according to claim 11, wherein the supporting casing has a flange which, in use, the end of the pipe engages.

13. A connector fitting according to any one of claims 1 to 12, wherein the inner frusto-conical surface is provided on a support ring which is arranged inside the housing.

14. A connector fitting according to claim 13, wherein the support ring directly engages one side of an O-ring which is engaged on the other side thereof by a cap screw or clamping nut constituting part of the housing.

1 5. A connector fitting according to any one of claims 1 to 14, wherein a supporting casing is integrally formed with a threaded pipe cnstituting part of the housing, the support casing and threaded pipe defining between them an annular space to receive the end of the synthetic pipe.

1 6. A connector fitting according to any one of claims 1 to 15. wherein the compression element is in the form of a clamping ring having an outer frusto-conical surface and an inner frusto-conical surface providing a cutting edge.

1 7. A connector fitting according to any of claims 1 to 16, wherein the peripheral seal comprises a sealing ring engaged on the one side by a clamping ring and on the other side by a connecting projection of a threaded pipe constituting part of the housing.

1 8. A connector fitting according to any one of claims 1 to 17, wherein sealing means are provided for sealing the threadedly engaged parts of the housing.

19. A connector fitting substantially as hereinbefore described with reference to Figure 1, Figures 2 and 3, Figure 4, Figure 5, Figures 6 to 8, Figure 9, Figure 10 or Figures 11 to 13 of the accompanying drawings.