Fastening element for hard constructional components

#1. Field of the Invention

#The present invention relates to a fastening element for hard constructional components such as concrete, masonry and the like and including a cylindrical base body extending along a longitudinal axis and having a first end and a second end opposite from the first end, a self-tapping thread provided, at least regionwise, on the outer surface of the base body and having a runout spaced from the first end to provide a thread-free section extending from the first end and in the direction of the second end, inwardly located engagement means for the setting bit, and an opening that is open toward the second end of the base body and, adjoins the engagement means in a direction toward the second end, and load application means.

#2. Description of the Prior Art

#The drawings show:

#FIG. 1 a cross-sectional view of a fastening element according to the present invention at the beginning of a setting process;

#FIG. 2 a side view of the fastening element according to the present invention; and

#A fastening element 21 for hard constructional component 11, which is shown in FIGS. 1-2, has a cylindrical base body 22 that extends along a longitudinal axis 3 and has a first and 24 facing in a setting direction S and a second opposite end 25. On an outer surface 26 of the base body 22, there is provided a self-tapping thread 27 having a runout 28 which is spaced from the first end 24 to provide a thread-free section 31 that extends from the first end 24 in a direction of the second end 25. The base body 22 further has inwardly located engagement means 32 for a setting bit 13, a receptacle opening 33 that is open toward the second end 25, adjoins, in the direction of the second end 25, the inwardly located engagement means 32, and is provided with an inner thread that serves as load application means 34.

#The thread-free section 31 has an axial extent E that is larger than an axial extent F of the inwardly located engagement means 32 that is located in the region of the thread-free section 31. In one embodiment, which is shown in FIG. 3, the axial extent (E) of the thread-free section (31) amounts at least to 0.5 times of a core diameter (D) of the base body (22). In another embodiment, the axial extent E of the thread-free section 31 corresponds to 0.7 times of the core diameter D of the base body 22. A region of the thread-free section 31 has a conical profile.

#For setting the fastening element 21, a borehole 12 is formed in the hard component 11, here, e.g., a concrete component, and the fastening element 21 is driven therein until the runout 28 of the self-tapping thread 27 engages the borehole mouth 14. A suitable setting bit 13 transmits, through the engagement means 32, a torque to the fastening element 21 and screws the fastening element 21 into the borehole 12, whereby the self-cutting thread 27 forms a complementary thread in the wall 15 of the borehole 12 to produce an undercut.