Positive locking fastener

A cap intended to engage with a nut and intended to receive a pin, said nut comprising a tightening portion of angular period θ about a main axis of said nut, said cap being substantially axisymmetric about a main axis and comprising:

• a blocking portion at a first end, said blocking portion defining an inner surface corresponding to a housing intended to engage with the tightening portion of the nut so that the main axis of said nut is substantially coincident with the main axis of the cap when said cap is in place on said nut;
• a locking portion at a second end, a side wall of said locking portion comprising at least one pair of through openings adapted to receive the pin, said openings of one pair being arranged symmetrically with respect to the main axis, in a direction defined by centers of said openings of the pair, the openings being similar in dimensions with a height h along the direction of the main axis and a length defined by an angular sector φ intended to allow a movement of a rectilinear part of the pin in any of the at least one pair of openings, said openings being located substantially at a same height of said main axis;
• said blocking and locking portions being fixed and secured together and said cap being characterized in that the angular sector φ is equal to:
• φ
• =
• θ
• N
• where N is a number of pairs of openings.