Couplings

A coupling for connecting together two fluid passages and through which fluid is to be transferred from one of the passages to the other, the coupling being of the kind which comprises two coupling parts each of which forms a respective one of the two fluid passages and is provided with an obturating member operable to close the respective fluid passage automatically, in a fluid tight manner, when the respective coupling part is disconnected from a mating coupling part, actuating means operable to effect decoupling and fluid tight coupling of the two coupling parts and to apply a thrust to said obturating members during coupling, so that the obturating members are displaced from their positions in which they close the respective through passages to allow fluid flow around the displaced obturating members from one passage to the other, and to return the obturating members to said positions for decoupling, wherein one of the obturating members has a face which is adjacent to a corresponding face of the other obturating member as those obturating members are displaced from said positions by said actuating means when the coupling parts are coupled together, wherein the improvement comprises said face of said one obturating member being formed of an elastomeric material and being profiled in its natural relaxed state such that, when it touches the adjacent face of the other obturating member without deformation of the elastomeric material, a radially extending tapering clearance is formed between those faces, said actuating means being adapted to apply an axial thrust through one of the obturating members to the other whereby the elastomeric material is compressed so that the clearance is taken up and fluid between those faces is squeezed out as the obturating members return to said positions prior to disconnection of the coupling parts, the elastomeric material of said one obturating member being in its natural relaxed state when the coupling parts have been coupled together and the obturating members have been displaced by said actuating means to rest positions which they occupy as fluid is transferred around them from one of the through passages to the other.