TUBE COUPLINGS FOR CONNECTING A PAIR OF CONDUITS FOR CARRYING A CABLE

Abstract

A tube coupling for connection to a conduit through which a cable may pass includes a coupling body having an open ended throughway to receive an end of the conduit and a tube locking device in the open end of the throughway for locking the conduit in the coupling body. The throughway has a reduced diameter section with an annular step at an end of the section facing towards the open end of the throughway to receive the end of the conduit inserted into the throughway. An annular flexible sealing member is disposed adjacent the step to be forced by an end of a tube inserted into the throughway into the reduced diameter section of the throughway. Compression of the annular flexible seal forces the seal into sealing engagement with a cable extending along the throughway to provide a seal between the coupling body and cable.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a description of some specific embodiments of the invention, reference being made to the accompanying drawings in which:

FIG. 1 is a cross-sectional view through a tube coupling for connecting lengths of optical fibre carrying conduiting with a gas block incorporated in the coupling;

FIG. 2 is a similar view to that of FIG. 1 with a pair of tubes inserted into each end of the fitting with the gas block deactivated;

FIG. 3 is a similar view to that of FIG. 2 with an optical fiber bundle shown blown through the fitting by air pressure from one end of the conduiting; and

FIG. 4 is a cross-sectional view through the fitting with the optical fiber passing through the fitting and the gas seal activated to prevent gas flow from one conduit to the next.

Claims

1. A tube coupling for connection to a conduit through which a cable (e.g., an optical fiber cable) may pass, the coupling comprising a coupling body having an open ended throughway to receive an end of the conduit for carrying a cable, a tube locking device in the open end of the throughway for locking the conduit in the coupling body, the throughway having a reduced diameter section part way along the throughway with an annular step at an end of the section facing towards the open end of the throughway to receive the end of the conduit inserted into the throughway, and an annular flexible sealing member disposed adjacent the step to be forced by an end of a tube inserted into the throughway into the reduced diameter section of the throughway, the resulting compression of the annular flexible seal forcing the seal into sealing engagement with a cable extending along the throughway to provide a seal between the coupling body and cable.

2. A tube coupling as claimed in claim 1, wherein the annular step at one end of the reduced diameter section with which the annular seal is engageable is inclined to provide a ramp leading from the throughway to the reduced section to guide the seal into the reduced section when pressed by a tube being inserted into the throughway.

3. A tube coupling as claimed in claim 1, wherein the annular seal comprises an annular sleeve of flexible material.

4. A tube coupling as claimed in claim 3, wherein the annular sleeve in uncompressed state is longer than the reduced diameter section in the throughway.

5. A tube coupling as claimed in claim 1, wherein the locking device in the open end of the throughway comprises a collet for gripping and locking the ends of the tube.

6. A tube coupling as claimed in claim 5, wherein the collet in the end of the coupling body comprises an annular head extending out of the throughway and having axially projecting legs extending into the throughway terminating in heads formed on their inner sides to grip a tube and engageable on their outer sides with a tapered cam surfaces formed in the throughway which forces the heads into engagement with a tube as the collet is drawn outwardly of the throughway.

7. A tube coupling as claimed in claim 1, wherein a seal is provided for engaging the outer surface of a tube adjacent at said end of the throughway adjacent the locking device.

8. A tube coupling as claimed in claim 1, wherein the coupling is intended to connect together a pair of conduits through which the cable passes, the coupling having locking devices for conduits at both ends and the reduced diameter section having annular steps on either side facing towards the ends of the coupling body to receive the conduit ends and the annular flexible sealing member is located on one side of the reduced diameter section.