Tube couplings

Abstract

A tube coupling has a coupling body with a throughway open at one end to receive an end portion of a tube. A seal encircles the throughway to seal with the periphery and end of the tube and a cap is mounted on the body having a tube locking device rotatably mounted in the cap to engage and hold the tube in the cap. The cap and body have interengaging means which guide the cap on the body in an axial direction along the body with rotation of the cap from a first position in which a tube can be inserted through the cap and into the seal in the throughway and retained by the locking device and a second position advanced along the coupling body from said one end in which the tube end is held positively in engagement with the seal in the throughway. The locking device engages via a ring with the coupling body to resist rotation of the locking device with respect to the body whereby rotation of the cap between said the first and second positions does not cause the tube to rotate.

1 . A tube coupling comprising a coupling body having a throughway open at one end to receive an end portion of a tube, a seal encircling the throughway to seal with the periphery and end of the tube and a cap mounted on the body having a tube locking device rotatably mounted therein the cap to engage and hold the tube in the cap in the axial direction out of the cap, the cap and body having interengaging means which guide the cap on the body in an axial direction along the body with rotation of the cap from a first position in which a tube can be inserted through the cap and into the seal in the throughway and retained by the locking device and a second position advanced along the coupling body from the end thereof in which the tube end is held positively in engagement with the seal in the throughway, wherein means are provided to resist rotation of the locking device with respect to the coupling body whereby rotation of the cap between said the first and second positions does not cause the tube to rotate.  
     
     
         2 . A tube coupling as claimed in  claim 1 , wherein an annular member is provided in the cap acting between the coupling body and tube locking device to resist rotation of the locking device with respect to the coupling body.  
     
     
         3 . A tube coupling as claimed in  claim 2 , wherein the annular member and an end of the coupling body have interengaging teeth to resist rotation of the annular member with respect to the coupling body.  
     
     
         4 . A tube connector as claimed in  claim 2 , wherein the annular member and tube locking device have interengaging teeth to resist rotation of the locking device with respect to the coupling body.  
     
     
         5 . A tube coupling as claimed in  claim 2 , wherein the annular member comprises a sleeve which engages in the open end of the throughway of the coupling body and has an out-turned flange overlying the end of the coupling body, the end of the coupling body and side of the flange facing the coupling body having interengaging teeth to resist rotation of the annular member with respect to the coupling body and the other side of the flange and tube locking device having interengaging teeth to resist rotation of the tube locking device with respect to the coupling body.  
     
     
         6 . A tube coupling as claimed in  claim 1 , wherein the locking device comprises a collet having an annular head located on the outer side of the cap and having a plurality of resilient arms projecting into the cap, the arms having interengaging teeth for engaging the tube extending through the collet into the coupling body and the cap having a tapered cam surface converging towards the open end of the cap remote from the coupling body with which the arms of the collet are engagable to be pressed inwardly with outward movement of the collet with respect to the cap to engage and grip the tube extending through the collet.  
     
     
         7 . A tube coupling as claimed in  claim 6 , wherein the ends of the arms of the collet projecting into the cap have teeth for interengaging with the teeth of the annular member for resisting rotation of the collet with the cap.