The CC1 Al-Fer dry connector consists of a single metal piece obtained from a Ø 16mm bar suitably machined with wood thread in the part to be secured on the beam.The bar remains smooth in the portion corresponding to the floor board to obtain the maximum diameter of the connector (ø16), while it returns with hexagonal head machining equipped with grooves in the part to be drowned in concrete.

The lower part, threaded with a continuous screw, was made with a constant diameter outer spiral while the central worm is conical with a reverse fit. In this way the fixed tip is more resistant to hooking in joists.

Ideally, it can be divided into three parts:

While head and thread are always present, the central body can sometimes be omitted. The following pages describe element details and specify their function.

The Al-fer CC1 dry connector head has a hexagonal section of 17 mm thickness and a height of 40 mm and is equipped with grooves to improve the concrete coupling.

The central body has a circular cross-section with a constant diameter of 16 mm. It has the role of absorbing the greater shear and momentum forces induced by external stresses on the mixed system, therefore the area resistant to shear/bending is considerable and equal to 200 square mm.

The thread is created with the external spiral with a constant diameter of 16 mm, while the central worm is conical with reverse fit. In other words, the central core of the thread has a circular section with a diameter of 11.5 mm near the central body of the connector and gradually widens to a diameter of 12 mm at the tip. This way the fixed tip is more resistant to mechanical coupling in the concrete.

This particular “taper” of the thread together with the appropriate calibration of the pre-drilled hole (d.14 mm) give the connector a considerable resistance to extraction, in fact, in the screwing phase the first 5 threads of the connector act as a male by cutting through the concrete. The resistance to extraction without the use of resins is maximum; on a very consistent concrete it is not possible to unscrew it but it must be eliminated with an angle grinder.