Self-tapping screw

US5294227A · kind A · utility

Assignee

• Hilti Aktiengesellschaft · LI

Inventors

• Hubert Forster · Moorenweis, DE
• Armin Herb · Apfeldorf, DE

Key dates

• Filing date: Nov 23, 1992
• Grant date: Mar 15, 1994
• Expiry date: Nov 23, 2012

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16B25/10
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A self-tapping screw has a cutting thread formed by two separate threads (3, 4). An imaginary envelope (5) defines a annular space (5) laterally enclosing the screw shank and has a section (5a) tapering inwardly along an inwardly tapering leading end section (1a) of the shank (1). The inwardly tapering section of the annular enclosing space an envelope forms an angle (B) considerably larger than the angle (A) formed by the tapering leading end section (1a) of the shank. The leading ends (3a, 4a) of the separate threads (3, 4) are located diametrically opposite one another for uniform distribution of the forces developed when the screw penetrates into a hard receiving material, such as concrete, masonry, gas concrete and the like.