Abstract: A joining device has a female part and a male part for joining with the female part. The female part has a retaining opening, and the male part has an inserting part for insertion in the retaining opening of the female part. The female part further has female shoulders that form an input of the retaining opening, and the inserting part has male shoulders. The male shoulders are inclined with respect to the female shoulders so that the contact between the male shoulders and female shoulders is reduced to a point when the inserting part is inserted in the retaining opening.

Abstract: Two joining parts (2, 3) made of molded plastic comprise the female part (6) and the male part (7) of the device. These parts are obtained by molding them at the same time as their joining parts. According to the invention, the female part comprises at least two symmetrical hooks (11, 12) which determine between them a first space (13) for inserting the male part, in a form widening towards the free end, and a second space (14) of rectangular or triangular section called retaining space. The interface between these two parts consists of two female shoulders (15, 16) for said hooks. The male part situated opposite comprises an inserting end (17) whose form is adapted to the first inserting space, which end is terminated by a common shoulder of the male part (18).