| 摘要 |
A vibration-proof anchor bolt assembly which is insertable in a hole drilled in masonry for fastening a fixture to the surface thereof, the diameter of the hole being slightly larger than that of the bolt. The bolt is provided with an enlarged head that lies against the fixture and is engageable by a torque tool, the threaded rear section of the bolt being of reduced diameter. The upper portion of the rear section is encircled by an expansible shell which when expanded is forced against the wall of the hole to anchor the bolt therein. Received on the lower portion of the rear section is a wedge nut having an upper conical zone and a lower ring zone whose normal diameter is larger than that of the hole, slots being cut into said ring zone to define spring fingers. These fingers are inwardly flexed by the wall on the hole when the assembly is inserted therein, thereby compressing the ring and constricting the internally-threaded bore thereof. When the bolt assembly is fully inserted in the hole and the bolt head is turned by the tool, the wedge nut, whose rotation is arrested by the compressed ring, is axially advanced toward the shell, the conical zone of the nut entering the space between the shell and the rear section and acting progressively to expand the shell against the wall of the hole until a point is reached where the threaded end of the rear section enters the constricted bore of the compressed ring. The resultant advance of the wedge nut wedges the threaded portion of the bolt between the compressed spring fingers, forcing these fingers outwardly against the hole of the wall, to create pressure between the mating threads which prevents loosening of the bolt under vibratory conditions. |
