A wheel hub unit having a central hub and a single central nut that includes respective shaped profiles radially oriented facing towards an axis (A) is provided. The wheel hub unit further includes an anti-unscrewing element interposed between the central hub and the single central nut to prevent accidental unscrewing of the single central nut. The anti-unscrewing element is provided with respective shaped profiles both radially oriented facing away from the axis (A) to engage with shaped profiles.

A wheel hub unit having a central hub and a single central nut that includes respective shaped profiles radially oriented facing towards an axis (A) is provided. The wheel hub unit further includes an anti-unscrewing element interposed between the central hub and the single central nut to prevent accidental unscrewing of the single central nut. The anti-unscrewing element is provided with respective shaped profiles both radially oriented facing away from the axis (A) to engage with shaped profiles.

A device with an adjustment bolt includes a bolt attachment wall, an adjustment bolt screwed with an internal thread hole of the bolt attachment wall, a locknut screwed with the adjustment bolt, a cover that surrounds the adjustment bolt and the locknut, and a stopper unit that prevents removal of the cover from the locknut. The stopper unit includes an inner circumference groove of the cover fitted around a C-shaped retaining ring, and an external circumference groove of the locknut fitting within the retaining ring. The external circumference groove includes a first groove portion having a large-diameter groove bottom that restricts contraction and removal of the retaining ring fitted within the inner circumference groove, and a second groove portion provided continuously for the first groove portion and having a small-diameter groove bottom that allows contraction and removal of the retaining ring fitted within the inner circumference groove.

A device with an adjustment bolt includes a bolt attachment wall, an adjustment bolt screwed with an internal thread hole of the bolt attachment wall, a locknut screwed with the adjustment bolt, a cover that surrounds the adjustment bolt and the locknut, and a stopper unit that prevents removal of the cover from the locknut. The stopper unit includes an inner circumference groove of the cover fitted around a C-shaped retaining ring, and an external circumference groove of the locknut fitting within the retaining ring. The external circumference groove includes a first groove portion having a large-diameter groove bottom that restricts contraction and removal of the retaining ring fitted within the inner circumference groove, and a second groove portion provided continuously for the first groove portion and having a small-diameter groove bottom that allows contraction and removal of the retaining ring fitted within the inner circumference groove.

A cap for attachment to a fastener comprises a securing base removably supported on a neck portion of the fastener, a hinge portion connected to the securing base, and a covering portion connected to the hinge portion. The securing base has a plurality of elastic beams defining a head portion passageway receiving a head portion of the fastener. The neck portion has a smaller diameter than a largest diameter of the head portion. The elastic beams are elastically deformed by the head portion during passage of the head portion through the head portion passageway. The covering portion is movable between an open position exposing the head portion and a covering position covering the head portion and overlapping with the securing base.

A coupling comprising a driven part and a driving part that is connected by a safety pin so as to drive the driven part together with the driving part in a travel direction, one of the parts having a male portion engaged in a female portion of the other part, the male and female portions respectively having a first guide surface and a second guide surface facing each other in such a manner that, in the event of the pin breaking, the driving part is capable of moving relative to the driven part in the travel direction, the pin extending perpendicularly to said direction through corresponding holes made in the male and female portions, the coupling being characterized in that the hole made in the male portion opens out in the bottom of a setback in the second guide surface.

A coupling comprising a driven part and a driving part that is connected by a safety pin so as to drive the driven part together with the driving part in a travel direction, one of the parts having a male portion engaged in a female portion of the other part, the male and female portions respectively having a first guide surface and a second guide surface facing each other in such a manner that, in the event of the pin breaking, the driving part is capable of moving relative to the driven part in the travel direction, the pin extending perpendicularly to said direction through corresponding holes made in the male and female portions, the coupling being characterized in that the hole made in the male portion opens out in the bottom of a setback in the second guide surface.

A fixing system for a rocker arm of a vehicle suspension has a threaded rod having a first thread, a second thread and a locking cavity. The fixing system has a first cam, integral for rotation with the threaded rod by shape-fitting coupling, a second cam integral for rotation with the threaded rod by shape-fitting coupling, a first nut, screwed onto the first thread to lock position of the first cam, and a second nut, screwed onto the second thread to lock position of the second cam and having a locking portion having a circumferential groove and a positioning hole passing through the circumferential groove. An elastic clip shaped as an open ring is accommodated in the circumferential groove for retaining a pin in the positioning hole. In a screwed position of the second nut, the pin fits into the locking cavity and locks the position of the second nut.

A fixing system for a rocker arm of a vehicle suspension has a threaded rod having a first thread, a second thread and a locking cavity. The fixing system has a first cam, integral for rotation with the threaded rod by shape-fitting coupling, a second cam integral for rotation with the threaded rod by shape-fitting coupling, a first nut, screwed onto the first thread to lock position of the first cam, and a second nut, screwed onto the second thread to lock position of the second cam and having a locking portion having a circumferential groove and a positioning hole passing through the circumferential groove. An elastic clip shaped as an open ring is accommodated in the circumferential groove for retaining a pin in the positioning hole. In a screwed position of the second nut, the pin fits into the locking cavity and locks the position of the second nut.

A mechanical seal that employs a lock ring assembly having associated therewith a locking mechanism. The locking mechanism can include a nut element, such as a barrel nut, that allows an associated bolt element to adjust a tightening load and position while clamping occurs of the components of the mechanical seal. This adjustment flexibility removes or reduces unwanted bending stresses in the bolt element, thus allowing for more torque to translate directly to the lock ring. The barrel nut allows for more material to remain in the lock ring, thus providing for additional overall strength relative to a traditional locking element. The lock ring also includes a plurality of flex regions in the form of notches that allow the lock ring to flex when the main body is tightened about the shaft.