US Patent 7661724 Quick coupling

A quick coupling comprises a male element (2) which can be threadably assembled to a female element (3), housing an inner tubular supporting body (8) in turn housing a bearing (11) thereon the female element (3) bears, the female element (3) including a plurality of radially extending holes (20) in which are engaged ball elements (21) which can be fitted in a circumferential slot formed in the male body (2) and being adapted to be radially locked by an enlarged portion (16) formed on an inner side of a ring nut which can be driven against an urging spring (17) pertaining to the female element.