Variably threaded screw
AssigneeSimpson Strong-Tie Company, Inc.
InventorLiu Yin-Feng
Life of this patent
Estimating the term…
Abstract
A variably threaded screw has a first end and a second end, the first end of the shaft terminating in a tip and the second end having a widened head thereon. A first helical thread portion is located on the shaft adjacent the widened head. A second helical thread portion is located on the shaft adjacent the tip of the shaft. A third helical thread portion is located on the shaft between the first helical thread portion and the second helical thread portion. The first helical thread portion and the second helical thread portion have right hand thread pitches. The third helical thread portion has a left hand thread pitch. A helical ridge having a right hand thread pitch intersects the third helical thread portion.
Claims18
A screw comprising:
- a shaft having a first end and a second end, said first end of said shaft terminating in a tip;
- a widened head on said second end of said shaft;
- a first helical thread portion on said shaft adjacent said widened head;
- a second helical thread portion on said shaft adjacent said tip of said shaft;
- a third helical thread portion on said shaft between said first helical thread portion and said second helical thread portion;
- said first helical thread portion and said second helical thread portion having substantially the same right hand thread pitch;
- and
- said third helical thread portion having a left hand thread pitch complementary to the right hand thread pitch.
A screw comprising:
- a shaft having a first end and a second end, said first end of said shaft terminating in a tip;
- a widened head on said second end of said shaft;
- a first helical thread portion on said shaft adjacent said widened head;
- a second helical thread portion on said shaft adjacent said tip of said shaft, the second helical thread portion not overlapping the first helical thread portion;
- a third helical thread portion on said shaft between said first helical thread portion and said second helical thread portion, the third helical thread portion not overlapping the first or second helical thread portion;
- said first helical thread portion and said second helical thread portion having substantially the same combined thread and shaft diameter excluding said tip;
- said first helical thread portion and said second helical thread portion having right hand thread pitches;
- said third helical thread portion having a left hand thread pitch complementary to the right hand thread pitch and angled substantially opposite from the right hand thread pitch.
A screw comprising:
- a shaft having a first end and a second end, said first end of said shaft terminating in a tip;
- a widened head on said second end of said shaft;
- a first helical thread portion on said shaft adjacent said widened head;
- a second helical thread portion on said shaft adjacent said tip of said shaft;
- a third helical thread portion on said shaft between said first helical thread portion and said second helical thread portion;
- said first helical thread portion, said second helical thread portion, and said third helical thread portion having substantially the same combined thread and shaft diameter excluding said tip;
- said fist helical thread portion and said second helical thread portion having substantially the same right hand thread pitch;
- said third helical thread portion having a left hand thread pitch complementary to the right hand thread pitch and angled substantially opposite therefrom.
Dependencies are inferred from the claim text.