1. The joint (14) includes a pair of links (12) and a cylindrical pin (52).

2. The support surface is provided with a cavity which contains a rounded member (e.g., a cylindrical pin).

3. The expanding element (11) has a cylindrical pin (4) at the rear end of which is an outwardly distortable collar (20).

4. A cylindrical pin is inserted in the pinhole such that safety rod (3) is pivotally connected to the stapler body.

5. Couplings having a cylindrical pin and which achieve vertical rotation for the coupled drawbar eye by means of a special joint will only be permitted when technical necessity can be demonstrated.