Abstract: A self-drilling dowel consists of a tubular-shaped member with a drilling head at one end. The drilling head is formed of a plurality of teeth each having a tip. The tip of the teeth are all disposed in a single plane inclined at an angle to the axis of the tubular-shaped member. A line perpendicular to the plane containing the tips of the teeth and intersecting the axis of the tubular-shaped member is disposed to the axis at an angle in the range of 4.degree. to 9.degree.. The teeth are formed by a cutter with its center located at an offset position from the axis of the tubular-shaped member. The feed line of the cutter extending through its center can be parallel to the axis of the tubular-shaped member or it can be set angularly to the axis of the tubular-shaped member in the range of 4.degree. to 9.degree. or 81.degree. to 86.degree. depending on whether the cutter is moved generally in the axial direction or transversely to the axial direction of the tubular-shaped member.

Abstract: In an expansion dowel assembly, a stud or bolt extends through an expansion sleeve with an expanding body on one end for radially spreading the sleeve and a head or first working part on the other end for applying torque. A second working part encloses the first working part and is attached to it by one or more shear members. Torque for anchoring the sleeve in a borehole is applied through the second working part to the first working part and the stud. When a preset torque is reached, the shear members break and the second working part can move relative to the first working part without transmitting torque to the stud. A separating member is provided between the first and second working parts and after the preset torque is attained, further torque can not be applied to the stud until the separating member is removed. Preferably, the separating member consists of a flange with outstanding fingers which are in contact with the surface of the first working part against which a torque applying tool is placed.

Abstract: An expansion dowel assembly includes a sleeve, a tie rod insertable into the sleeve, an expanding body connected to one end of the tie rod and an end support on its other end. A member is connected to the end support for transmitting torque to it and by virtue of the torque applied to the end support the expanding body is drawn into the sleeve causing it to expand. Shear pins connect the member to the end support and when a predetermined torque is reached the pins shear off and the member can be removed from the end support. The shear pins can be arranged either parallel or perpendicular to the axis of the tie rod.

Abstract: A holder for a self-drilling dowel has a frusto-conically shaped bore for holding the locking-in cone on the dowel. The surface of the bore has three uniformly angularly spaced rounded recesses so that three relatively narrow strips of the surface provide contact with the locking-in cone.