Concrete screw
US4842467A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 9, 1987 |
| Grant date | Jun 27, 1989 |
| Priority date | — |
| Expiry date | Nov 9, 2007 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16B35/048
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A self-tapping screw for use on concrete and masonry structures is disclosed. The screw has a helically threaded shank of uniform diameter. The crest diameter of the helical thread on the shank has a taper which increases gradually from the tip or entering end of the shank for a predetermined distance along the shank and then has a uniform diameter over the remaining portion of the helical thread. The helical threads have a spacing of 5-8 threads per inch for screw sizes in the range of 1/2 to 3/16 inch. Thread cutting notches are formed in the threads over at least the tapered portion thereof. The screw is hardened to a Rockwell "C" hardness of 48 or greater.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.