GB2049856A

GB2049856A - Tube and nipple coupling

Info

Publication number: GB2049856A
Application number: GB8014873A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-05-08
Filing date: 1980-05-02
Publication date: 1980-12-31
Also published as: GB2049856B; JPH0121394B2; SE417005B; JPS55155992A; SE7903991L; DE3017375A1; DE3017375C2

Abstract

A locking device is used for locking a resilient tube 4 to a nipple provided with at least one flange 1b. The device comprises a sleeve 3 which is separate from the nipple and which can be threaded over the flange 1b of the nipple. The sleeve is applied on the nipple and after that the tube 4 is threaded over the flange 1b and in between the inner wall of the sleeve 3 and an outer wall of the nipple. Upon applying a force which tends to separate the tube and the nipple, the sleeve is actuated to a longitudinally displaced position and in this position, together with the flange 1b, prevents the separation of the tube 4 and the nipple by clamping the end of the tube 4. The tube 4 is forced on to the nipple and, inter alia this forcing provides enough sealing between the tube 4 and the nipple against a media which is conducted inside the mentioned components when the media pressure is small. If the media pressure increases so it separates the tube and the nipple, the sealing is provided by means of the sleeve. An O-ring (6, Fig. 1c) may be placed at the bottom of the sleeve. <IMAGE>

Description

SPECIFICATION Locking device The present invention relates to a device for locking a resilient pipe or hose to a nipple or the like. Pipes or hoses of plastics, for example polythene, nylon, etc, rubber or the like may be mentioned as examples of resilient pipes or hoses.

The nipple serving as a male member can be included as an input or output connection in the system, for example the hydraulic or pneumatic system, machines, components or other equipment. The nipple may also in turn be fixed in another pipe which is to be joined to the existing pipe or hose.

A long series of locking devices for pipes or hoses to nipples or the like are already known.

Apart from the anchoring function, sealing should also be effected between the pipe and the nipple for the medium conveyed through the pipe and the nipple.

Said previously known locking devices have disadvantages however, in that they are comparatively bulky from the space point of view and/or are made comparatively complicated with the necessary manual mounting which includes some form of screwing or pressing which requires space for accessibility.

The main object of the present invention is to provide a locking device which affords simple mounting of the pipe or the like to the nipple and which is of the so-called self-locking type which reliably holds the pipe on the nipple once the pipe has been fixed.

According to the invention, the new locking device comprises a sleeve which is spearate from the nipple and which can be threades over a flange projection situated on the nipple to a threades position on the nipple and in said threaded position, the sleeve is longitudinally displaceable in relation to the nipple. The sleeve and the flange are selected with such an internal and external diameter respectively that in a first longitudinally displaced position of the sleeve, the end of the pipe can be threaded over the flange and in between the inner wall of the sleeve and an outer wall situated below the flange on the nipple and in another longitudinally displaced position of the sleeve, the flange and the sleeve lock the end of the pipe to the nipple against forces which tend to separate the pipe and the nipple.

In further developments of the idea of the invention, a more precise construction of the locking sleeve and the flange is proposed as well as a more precise mutual placing of the flange and the sleeve which provides reliable anchoring against even greater external forces and media forces which tend to separate nippie and pipe.

What can mainly be regarded as characteristic of a device according to the invention can be seen from the characterising part of the following Patent Claim 1.

Through the invention a simple locking device is provided which affords so-called automatic mounting of the pipe or hose otn the nipple and i after its fixing is completely self-iocking, without the locking sleeve needing to be screwed into any threads or the hose needing to be provided with a clamping joint. The new locking device has small external dimensions which are close to the external dimensions of the pipe and the nipple, which simplifies the passage of the hose or pipe through rubber seals and the like for example, such as sound-insulating equipment and components.

Said further developments render it possible, inter alia, to ensure that it is possible to check that the end of the pipe has been pushed in sufficiently into the sleeve. A specific formation of the flange means that this is prevented from cutting into the material of the pipe when there are particularly strong forces, with the risk of causing a breaking therein.

Tensile tests have shown that the new locking device is effective and that it is substantially as strong as the rest of the hose.

A form of embodiment proposed for the present which has the characteristics which are significant for the invention will be described below with reference to the accompanying drawing in which Figure 1 shows, in longitudinal section, the end of a pipe which is forced over a flange situated on the nipple and into a sleeve which is mounted on the nipple and which assumed a first longitudinally displaced position on the nipple.

Figure 1 a shows details of the end of the pipe, the nipple and the sleeve when the latter assumes another longitudinally displaced position on the nipple, and Figures 1 b~1 c show further details of modifications of the locking device.

Figure 2 shows, in side view, the end of the pipe, the sleeve and the nipple separated from one another.

In the Figures, a nipple of brass or a corresponding material is shown at 1. The nipple can be connected to a system, for example for hydraulics or pneumatics, a machine part or other equipment component and the connection can be carried out in a manner known per se via a base portion 1. The nipple is provided with a projecting flange 1 b which narrows off towards the front end 1 c of the nipple. The flange has a straight side surface 1 b' which is substantially parallel to the central line 2 of the nipple. The height of said straight side surface depends on the forces which are to be taken up by the locking device. The greater the forces, the higher the surface.Suitable values for said height (width) lie within the range of 0,1~1,5 mm for nipples for > " pipe. The straight under surface 1 b" merges into a straight outer wall 1 d which is parallel to the central line 2.

At the lower parts, the nipple is provided with a tapered surface 1 e which inclines outwards from the straight outer wall 1 d to the securing part 1 a.

The locking device comprises a locking sleeve 3 which in the present example of embodiment is made of brass or a corresponding metal but which can be made of another material, for example plastics. The sleeve is cup-shaped in principle and has at one end a gable or a folded-in edge 3a and a through hole 3b. At its other end, the sleeve is completely open and provided with an outwardly curved portion 3c. At the end first mentioned, the sleeve is provided with a number of side holes 3d which serve as inspection holes. The sleeve shown has a wall thickness of about 0.5 mm. The external diameter of the flange is given by ND. The diameter of the straight outer wall is designated by Nd.

The sleeve can be threaded into a threaded position over the flange 1 b, the sleeve being threaded via said through hole 3b. In a fully threaded position, which corresponds to the position according to Figure 1, the sleeve bears with its folded-in edge 3a against a surface 1 a' on the securing portion 1 a. In said fully threaded position, which is here called the first longitudinal displacement position, the upper end of the sleeve is situated under the flange so that a spacing a between the points situated closest to one another on the flange 1 b and the sleeve 3 is greater than the wall thickness b in a pipe or a hose 4 which is to be anchored to the nipple by means of the sleeve 3. The internal diameter of the sleeve is given by HD.In an embodiment where there is a strong demand for anchoring, the sleeve can be provided with internal grooves 3e, projecting teeth or the like projecting members.

The hose or pipe may be made of polythene, nylon, rubber etc. During the actual anchoring of the pipe, the sleeve is first threades (forced) over the nipple into said fully threaded position or the first longitudinal displacement position, which is indicated in Figure 1 by 3c'. Then the pipe or hose is threaded over the flange and into the sleeve 3.

The flange narrowing forwards takes up tolerances in the internal diameter of the pipe and the outwardly curved portion 3c on the sleeve means that the guiding in of the end of the pipe is facilitated when the end of the pipe is inserted in the sleeve During the insertion, the sleeve is pressed into or held in the first longitudinal displacement position by the actual pipe. The insertion of the pipe in the sleeve is rendered possible by the fact that the spacing a is equal to or greater than the wall thickness b of the pipe.

The internal diameter HD of the sleeve is selected somewhat larger than the diameter Nd plus substantially twice the wall thickness b. The angle on the tapered surface is selected so that a certain wedging function is obtained by the lower parts of the sleeve in conjunction with the pressing of the pipe. Among other things, a satisfactory sealing is obtained as a result.

The frictional forces from said wedging function and the forcing of the flange 1 b and the outer wall id on the nipple hold the end of the pipe in position on the nipple with minor forces F, for example external forces in the fastening and/or media forces, which tend to separate the pipe and the nipple. With greater forces F, the sleeve follows into another longitudinal displacement position which is indicated by 3c" in Figure 1 a. As a result of this longitudinal displacement movement, a spacing a' is obtained between the nearest points on the flange 1 b and the sleeve 3, which spacing a' is less than the wall thickness of the pipe in its forced-out position over the flange 1 b. The spacing a' depends on the magnitude of the force F and the elasticity in the pipe. The greater the force F and the elasticity, the smaller the spacing 1'.The above means that a constriction 4a forms in the material of the hose or pipe and that an accumulation of material 4b develops below the constriction and effectively prevents the separation of the pipe and the nipple.

The straight side surface 1 b' on the flange prevents the flange from cutting into the pipe material and causing a breakage in this. When said great force F ceases, the sleeve sinks back into its first longitudinal position and so on.

Said inspection holes guarantee that it is possible to check that the end of the pipe is sufficiently far into the sleeve for there to be reliable anchoring. During bursting tests with the invention, with 2111 pipe, the locking device withstood about 83 kp/cm2 media pressure, at which the pipe burst. An important feature of the locking arrangement according to the form of embodiment described above is that the internal diameter HD of the sleeve should be below the external diameter of the flange plus twice the wall thickness which the pipe has in position on the flange. In an example of an embodiment, HD was selected as 13,3 mm and ND as 11,0 mm. With a wall thickness of 1,5 mm, therefore, ND+2 . b=1 4,0 mm that is to say 0,7 mm greater than HD.The internal diameter of the pipe is about .9,5 mm, which gives an effective sealing or forcing on. With a vacuum connection, for example, it may be advisable to provide the nipple with some form of sealing ring which can be placed following on the lower tapered surface of the nipple, following on the inner end of the pipe, see below.

The sleeve can also serve as a clamping joint.

By means of a clamping tool 5 indicated diagrammatically, the sleeve can be clamped, for example when it assumes the position shown in Figure 1a.

Important features of the subject matter comprise i.a. that the sleeve, apart from eventual ridges, theets, etc. projecting inwardly from its inner wall, having substantially the same inner diameter along the main part of its length extension. The mentioned outer wall id, 1 e of the nipple comprises a straight portion id and a conical portion 1 e which is broaden from the straight portion to the member 1 a, which serves as a stop member. The sleeve having such a position on the nipple that it in the first longitudinally displaced position interacts with said stop member 1 a via the outer surface of the flange 3a of the sleeve. The inner diameter HD' then corresponds substantially the diameter ND' for the base of said conical portion. The sleeve having a length which substantially corresponds to the length of said outer wall 1 d and 1 e of the nipple. Apart from member 3c the sleeve has a length only a bit shorter than said outer wall id and 1 e and said length is at least 80% of the outer wall. In the shown embodiment the whole length (including the member 3c) is shorter than said outer wall and is at least 90% of said outer wall. In such a way the locking sleeve will perform comparatively small displacements in the longitudinal direction, i.e. the distance between the first and second displacements positions is comparatively small and the locking sleeve will in such a way not leeve its locking interaction with the tube end.

The conical portion le is about 1/5 of the whole length of said outer wall id and 1 e and the range covered by the subject matter is 10~30% of said whole length. Opposite to the outer wall portion id, there is a small space between the inner wall of the s!eeve and the outer wall portion of the tube 4, see Fig. 1. Opposite said conical portion 1 e, there is no such a space because of said conical surface, which eliminates the diameter tolerances of the tube. The sleeve is thinwalled and having a goods thickness of 0,2-0,8 mm due to the diameter of the tube which is to be locked. By the disclosed design of the sleeve this one can be punshed in one moment or step.

The invention is not restricted to the form of embodiment shown by way of example according to the above but can be subjected to modifications within the scope of the idea of the invention and the following patent claims. So far as the measurements of surfaces and other parts selected above are concerned, these have been determined in relation to the position on the Figures of the drawing used. If the Figures are turned, the mutual relations are changed over, for example so that the upper surface 1 a' becomes the under surface 1 a' if the Figure is turned 1 800 and so on. The sleeve can also be provided with longitudinal or transverse slits.The nipple may also comprise a further flange which is situated above the flange 1 b so that a more effective sealing is obtained between pipe and nipple, which sealing according to the above is determined inter alia by means of the degree of forcing of the pipe.

In certain cases it may be desirable from the handling, storage and/or service point of view to have the sleeve 3 hanging on the nipple when it has once been threaded on the nipple, as a best form of embodiment. Figure 1 b is intended to show this. The nipple is lengthened and provided under the tapered surface 1 e' with a recess 1 f.

Thus the tapered surface forms a flange with a shape like that of the flange 1 b but the straight side surface can be omitted. The flange formed by the tapered surface 1 e' has an external diameter ND' which somewhat exceeds the external diameter ND which somewhat exceeds the extemal diameter ND of the flange 1 b. The folded-in edge 3a' is selected so that a snap function is obtained for the sleeve over the flange forming the tapered surface, that is to say the through hole 3b' has a diameter HD' which is ess than the diameter ND' by some tenths of a mm so that firm snapping can take place. The recess if has a height which permits the longitudinal displacement movements of the sleeve between the first and second longitudinal displacement positions 3a' and 3a" respectively.

In certain cases, for example with a vacuum connection, it may be desirable to use resilient sealing rings (O-rings) 6 of VITON, nitrile etc following on said recess 1f', see Figure 1 c. The sealing ring is placed on the inside of the folded-in edge 31 of the sleeve 3 and can cooperate with the end surface of the pipe 4'. The height of the recess if' is greater than the height of the recess if so that there may be room for said sealing ring.

The invention proposes a locking device which consists of parts which are simple to manufacture for example in a factory and permits simple hose and pipe assembly in the factory and in the field.

The new locking device can also be sold and utilized commercially in other ways.

Claims

1. A device for locking a resilient pipe to a nipple or the like, and wherein the nipple having at least one projecting flange and an outer wall positioned below the flange; said locking device comprising: a sleeve which is separate in relation to the nipple and which is adapted to be threaded over said projecting flange of the nipple into a threaded position on the nipple; and wherein; said sleeve is adapted to be longitudinally displacable on the nipple, the sleeve and the flange are selected with such internal and external diameters that in a first longitudinally displaced position of the sleeve, the end of the pipe can be threaded over the flange and in between the inner wall of the sleeve and said outer wall on the nipple; and the sleeve and the flange is adapted to in another longitudinal displacement position of the sleeve lock the end of the pipe to the nipple against forces which tend to separate the pipe and the nipple.

2. A device as claimed in claim 1, and wherein said internal and external diameters on the sleeve and flange respectively are selected so that the internal diameter of the sleeve is less than the external diameter of the flange plus substantially double the wall thickness of the pipe.

3. A device as claimed in claim 1 and wherein the sleeve is provided, at one end, with a gable or a folded-in edge which comprises or forms a central through hole, through which the sleeve can be threaded over the nipple and its associated flange.

4. A device as claimed in claim 1 and wherein the sleeve has another end which, when the sleeve is in position on the nipple, is situated following on said flange; and wherein the sleeve is made at the last-mentioned end with an outwardly curved portion.

5. A device as claimed in claim 1 and wherein the sleeve is made with members projecting from its inner wall, for example in the form of ridges, teeth or the like.

6. A device as claimed in claim 1 and wherein the flange is shaped so as to narrow off towards the free end of the nipple and merge into a straight under surface in said outer wall situated under the flange on the nipple.

7. A device as claimed in claim 1 and wherein the flange has a straight side surface which is substantially parallel to the centre line of the nipple.

8. A device as claimed in claim 1 and wherein the sleeve is made with one or more inspection holes to render it possible to check the degree of insertion of the pipe in the sleeve when the pipe is inserted in the sleeve.

9. A device as claimed in claim 1 and wherein the sleeve is adapted to cooperate with a pair of clamping pincers by means of which the sleeve is deformable so that it serves as a clamping joint.

10. A device as claimed in claim 1 and wherein in said first longitudinal displacement position, the sleeve is situated with its gable or folded-in edge opposite a tapered surface on the nipple, which tapered surface follows on said outer wall with its narrower portion and on a base portion belonging to a nipple with its widest portion.

ii. A device as claimed in claim 1 and wherein the sleeve is adapted to be snapped into a groove in the nipple and the groove is adapted to permit the longitudinal displacement movements of the sleeve with a sealing ring which may be situated iti between.

12. A device for locking a resilient pipe to a nipple or the like, constructed and arranged substantially as hereinbefore described with reference to the accompanying drawing.

12. A device as claimed in claim 10 and wherein the sleeve, apart from eventual ridges, theets, etc. projecting inwardly from its inner wall, having substantially the same inner diameter along the main part of its length.

13. A device as claimed in claim 12 and wherein the sleeve having a length which is at least 80 % of the length of the outer wall of the nipple which comprises a straight outer wall portion and said tapered surface, and wherein the tapered surface having a length which is 10-30 % of the outer wall length.

14. A device for locking a resilient pipe to a nipple or the like constructed and arranged substantially as hereinbefore described with reference to the accompanying drawing.

New claims or amendments to claims filed on 18th Sept 1980 Superseded claims 1 to 14. New or amended claims:~

1. A device for locking a resilient pipe onto a nipple or the like, the nipple having at least one projecting flange at or adjacent its free end, wherein the nipple has a stop surface spaced from the flange and that part of the axial surface of the nipple between the flange and stop surface and adjacent the latter is tapered so as to diverge towards said stop surface, and wherein the locking device comprises a separate sleeve which has a folded-in edge at one end thereof to form a central through-hole adapted to pass over said projecting flange of the nipple so as to locate on the nipple, and be longitudinally displaced thereon, the sleeve and the flange are selected with such internal and external diameters that, in a first longitudinally displaced position of the sleeve, with its said one end adjacent the stop surface, the end of the pipe can be threaded over the flange and in between the inner wall of the sleeve and said outer wall on the nipple; the sleeve thereafter being forced towards the flange into another longitudinally displaced position in which the outer end of the sleeve performs a wedging function on that part of the pipe located over the projecting flange of the nipple and thereby locks the pipe against forces which tend to separate the pipe and nipple.

2. A device as claimed in claim 1, wherein said internal and external diameters on the sleeve and flange respectively are selected so that the internal diameter of the sleeve is less than the external diameter of the flange plus substantially double the wall thickness of the pipe.

3. A device as claimed in claim 1 or 2, wherein the said other end of the sleeve is outwardly curved so as to facilitate guiding of the end of the pipe into the sleeve during fitting and to enhance its wedging function in use.

4. A device as claimed in claim 1, 2 or 3, wherein the sleeve is provided with members projecting from its inner wall in the form of ridges, teeth or the like.

5. A device as claimed in any one of claims 1 to 4, wherein the flange is shaped so as to narrow off towards the free end of the nipple and at its inner end merges into a straight under surface extending transversely from said axial surface of the nipple.

6. A device as claimed in any one of claims 1 to 5 wherein the flange has a straight side surface which is substantially parallel to the centre line of the nipple.

7. A device as claimed in any one of claims 1 to 6, wherein the sleeve is made with one or more inspection holes for checking the degree of insertion of the pipe in the sleeve during fitting of the pipe.

8. A device as claimed in any one of claims 1 to 7, wherein the sleeve is adapted to co-operate with a pair of clamping pincers by means of which the sleeve is deformable so that it serves as a clamping joint.

9. A device as claimed in any one of claims 1 to 8, wherein the sleeve is adapted to be snapped into a groove in the nipple and the groove is adapted to permit the longitudinal displacement movements of the sleeve with a sealing ring which may be situated in between.

10. A device as claimed in any one of claims 1 to 9, wherein the sleeve has substantially the same inner diameter along the main part of its length, apart from any projecting ridges, teeth or the like which may be provided in accordance with Claim 4.

ii. A device as claimed in any one of claims 1 to 10, wherein the sleeve has a length which is at least 80% of the axial length of the nipple between its flange and stop surface, and wherein the tapered axial surface part of the nipple has a length which is 10~30% of said axial length of the nipple between its flange and stop surface.