A medical coupling has male and female members (1, 2) which push fit together, and a screw cap (7) which secures the members against separation. To prevent unintentional release of the cap, locking means, such as a ratchet and pawl mechanism, are provided between the cap and female...http://www.google.de/patents/US5830195?utm_source=gb-gplus-sharePatent US5830195 - Couplings for medical cannulae
