Abstract: A safety disk assembly is used in determining when a predetermined force is exerted in tightening a nut, bolt or similar fastening member to a base structure. The safety disk assembly is positioned between a fastening part, such as a nut, and the surface of the base structure. The safety disk assembly includes a first disk and a second disk with a shear pin interconnecting them. Additional shear elements can be used in the assembly. Preferably, a thin layer of Teflon is positioned between the disks. When a torque is applied to the fastening member, the shear pin breaks when a predetermined break point is reached. The friction coefficients of the disk surfaces and the effective radii of the disks are selected to provide the predetermined break point characteristics. When the shear pin breaks one of the disks can move relative to the other. An indicator is incorporated into the safety disk assembly to show when the predetermined break point has been exceeded.

Abstract: In a straddling dowel or expansion anchor assembly, a threaded bolt or stud has a head or nut adjacent one end for securing a member onto a support structure. The bolt is threaded into one end of a sleeve-like member and a threaded projection extends axially from the other end of the member with the projection extending axially through an expansion sleeve. A spreader is threaded onto the outer end of the projection for use in expanding the expansion sleeve. A device interconnects the bolt or stud and the sleeve-like member so that rotation of the bolt is transmitted to the sleeve-like member for pulling the spreader into and expanding the expansion sleeve. When a minimum anchoring value of the anchor within a borehole is achieved, the interconnection is disengaged. By continued rotation of the bolt or stud the member can be secured to the support structure with the interconnecting device being completely enclosed within the anchor structure.

Abstract: An anchor bolt assembly for insertion into a borehole includes an elongated anchor bolt and an expanding member which is forced radially outwardly into locking engagement with the borehole surface by pulling the anchor bolt through the expanding member in the direction out of the borehole. A stop is provided on the anchor bolt which contacts the expanding member after the locking engagement has been effected and prevents the anchor bolt from being pulled completely through the expanding member. Such a stopping action avoids the loss of the anchoring ability of the assembly.

Abstract: An expansion dowel includes an axially extending sleeve with an axially extending slot in the sleeve. The sleeve has protrusions extending generally circumferentially around and outwardly from the outer surface of the sleeve. At least some of the protrusions are formed each about a central axis extending at an acute angle to the axis of the sleeve. Adjacent pairs of the protrusions are located in planes which intersect on one side of the axis of the sleeve.