Coupling for forming a sealed joint between first and second tubular members

A coupling (10) for use in forming a sealed joint between first (36) and second (34) tubular members, the coupling (10) providing a through-passage (16) defined by an inner coupling face (24) and having:

• a first open end (12) for insertion of the first tubular member (36) into a first region (18) of the through-passage (16) the first open end (12) having a first inwardly directed engagement recess (26), which is provided in the inner coupling face (24) in the first region (18) of the through-passage (16), the first inwardly directed engagement recess (26) being alignable, in use, with a first outwardly directed engagement recess (40) of the first tubular member (36) to form a first channel for receipt of a first retainer (52) to secure the first tubular member (36) in the coupling (10);
• and
• a second open end (14) for insertion of the second tubular member (34) into a second region (20) of the through-passage, the second open end (14) having a second inwardly directed engagement recess (32), which is provided in the inner coupling face (24) in the second region (20) of the through-passage (16), the second inwardly directed recess (32) being alignable, in use, with a second outwardly directed engagement recess (42) of the second tubular member (34) to form a second channel for receipt of a second retainer (62) to secure the second tubular member (34) in the coupling (10), the coupling being characterised by:
• the first region (18) of the through-passage (16) having a larger diameter than the second region (20) of the through-passage (16).