Tube couplings

Abstract

A tube coupling includes a body having a cylindrical projection to engage in a tube to be secured to the body. A grab ring is mounted by arms having openings to snap onto abutments on the coupling body. The grab ring encircles with a clearance the projection and engages an outer surface of a tube pushed onto the projection to grip and resist withdrawal of the tube from the projection.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be discussed with reference to the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope.

FIG. 1 is an exploded perspective view of a tube coupling comprising a coupling body, grab ring for securing a tube to the coupling body and tube;

FIG. 2 is a section view through a tube coupling body with grab ring in situ to receive a tube;

FIG. 3 is a similar view to FIG. 1 showing the tube secured to the coupling body by the grab ring;

FIG. 4 is a further view with the tube detached from the coupling body with the grab ring;

FIG. 5 is a similar view to FIG. 1 showing a modified arrangement; and

FIG. 6 is a cross-section view through the arrangement of FIG. 5.

Claims

1. A tube coupling comprising a coupling body having a cylindrical projection to engage in a tube to be secured to the body, and a grab ring mounted externally of the Coupling body and encircling with a clearance the projection to engage an outer surface of the tube located on the projection to grip and resist withdrawal of the tube from the projection.

2. A tube coupling as claimed in claim 1, wherein the coupling body has a throughway extending through the projection for flow of a gas or liquid between the tube and coupling body.

3. A tube coupling as claimed in claim 1, wherein the projection has an encircling seal to seal with the internal surface of a tube located on the projection.

4. A tube coupling as claimed in claim 3, wherein the projection has an encircling groove and an O-ring seal is located in the groove to engage and seal with the internal surface of a tube located on the projection.

5. A tube coupling as claimed hi claim 1, wherein the projection has encircling barbs, an encircling annular bumper lip or is of “fir-tree” form to engage in the tube.

6. A tube coupling as claimed in claim 1, wherein the coupling body has a main portion from which the cylindrical projection extends and an axially facing shoulder encircling the projection to receive an end of a tube located on the projection and the grab ring is mounted on the main portion of the coupling body with the ring spaced from the shoulder to engage and lock with the outer surface of a tube located on the projection at a location spaced from the end of the tube.

7. A tube coupling as claimed in claim 1, wherein the grab ring has means to mount the grab ring on the main portion of the coupling body with the ring spaced along the projection from the main portion.

8. A tube coupling as claimed in claim 7, wherein the means to mount the grab ring on the main portion of the coupling body comprises one or more legs extending axially from the grab ring to the main portion of the coupling body.

9. A tube coupling as claimed in claim 8, wherein the grab ring has at least two legs projecting from the ring at spaced locations to the main portion of a coupling body.

10. A tube coupling as claimed in claim 9, wherein detent means are provided between the legs and main portion of the coupling body to retain the grab ring in position around the projection of the coupling body.

11. A tube coupling as claimed in claim 10, wherein the main portion of the coupling body has radially projecting lugs spaced around the coupling body and the grab ring has apertures which snap around the lugs to retain the legs and thereby the grab ring in position on the coupling body.

12. A tube coupling as claimed in claim 8, wherein the legs of the grab ring are integrally moulded into the main portion of the coupling body to locate the grab ring around the projection.

13. A tube coupling as claimed in claim 1, wherein the grab ring comprises a cylindrical element having an inturned flange at one end formed with internal teeth to grip and engage a tube inserted through the grab ring on the projection.

14. A tube coupling as claimed in claim 1, wherein the means to mount the grab ring on the coupling body comprise a sleeve in which the grab ring is formed.

15. A tube coupling as claimed in claim 14, wherein the sleeve extends over a portion of the coupling adjacent the projection and is moulded or crimped to the coupling.

16. A tube coupling as claimed in claim 1, having a cap to fit the coupling body and enclose the projection with an aperture in the top of the cap through which a tube is inserted onto the projection of the coupling body.

17. A tube coupling as claimed in claim 1, including a device to slide along a tube located on the cylindrical projection to release the grab ring from the tube and allow the tube to be withdrawn from the grab ring/projection.