Screw with cutting edge

• US 6,328,516 B1
• Filed: 03/28/2000
• Issued: 12/11/2001
• Est. Priority Date: 03/28/2000
• Status: Expired due to Term

• Current Assignee: Ludwig Hettich & Co.
• Original Assignee: Ludwig Hettich & Co.
• Inventors: Hettich, Ulrich
• Primary Examiner(s): Saether, Flemming
• Application Number:
  US09/536,612
• Time in Patent Office: 623 Days
• Field of Search: 411/386, 411/387--38, 411/413, 411/311
• US Class Current: 411/387.2
• CPC Class Codes: F16B 25/0015 the material being a soft organic material, e.g. wood or plastic F16B25/0031 takes precedence
• CPC Class Codes: F16B 25/0068 with multiple-threads, e.g. a double thread screws
• CPC Class Codes: F16B 25/0073 characterised by its pitch, e.g. a varying pitch
• CPC Class Codes: F16B 25/0084 characterised by geometric details of the tip
• CPC Class Codes: F16B 25/103 by means of a drilling screw-point, i.e. with a cutting and material removing action

Abstract

A screw has a shank portion (20) provided with a thread (21) and passing over via a transition into a conical tip (22). One or more parallel fins (24) are provided at least in the area of the tip. They are formed with cutting edges (23) and preferably disposed at an angle of inclination (13) of no less than 5° with respect to the longitudinal axis of the screw. The fins (24) project beyond the core diameter (1) of the shank portion (20). The conical tip (22) includes a finless end portion (26). The thread (21), however, extends across the full length of the tip (22).

Claims

1. A screw comprising a shank portion (20), a thread (21), a conical tip (22), and at least one cutting edge (23), wherein

(a) the thread (21) extends at least over part of the length of the shank portion and over the entire length of the tip (22) of the screw,

(b) one or more fins (24) project beyond the core diameter (1) of the shank portion (20), the leading edge of each of said one or more fins being circumferentially spaced from the trailing edge of the adjacent one of said one or more fins;

(c) the cutting edge (23) is formed on said at least one or more fins (24),

(d) said at least one or more fins (24) defining a smaller angle of inclination (13) than the thread (21) with the longitudinal axis of the screw, and

(e) the cutting edge (23) of said at least one or more fins extending over part of the conical tip (22) up to a finless end portion (26) of the said conical tip (22).

2. The screw as claimed in claim 1, wherein the angle of inclination (13) of each fin (24) with respect to the longitudinal axis (10) of the screw is greater than 5°

.

3. The screw as claimed in claim 2, wherein the angle of inclination (13) of each fin (24) with respect to the longitudinal axis (10) of the screw being approximately 15°

.

4. The screw as claimed in claim 1, wherein each fin (24) ends at the (25) between the shank portion (20) and the tip (22).

5. The screw as claimed in claim 1, wherein each fin (24) extends into the shank portion (20), passing beyond the transition (25) between the shank portion (20) and the tip (22).

6. The screw as claimed in claim 1, wherein said at least one fin (24) has a left-hand twist.

7. The screw as claimed in claim 1, including between two and eight fins (24) evenly distributed around the circumference of said shank portion.

8. The screw as claimed in claim 1, wherein each fin (24) is asymmetrical in cross section, and the fin flank is oriented with the steeper flank angle (15) in the screw-in direction.

9. The screw as claimed in claim 1, wherein the pitch angle (4) of the thread (21) is between 16°

and 20°

.

10. The screw of claim 9 wherein said pitch angle is approximately 19°

.

11. The screw as claimed in claim 1, including at least one additional fin (24′

) with a cutting edge (23′

) extending from the termination of the thread towards a threadless shank portion (19).

12. The screw as claimed in claim 11, wherein said additional fin (24′

)the same configuration and angle of inclination (13) as the fin (24) in the tip area.

13. The screw as claimed in claim 11, wherein the diameter (12′

) of the additional fin (24′

) is greater that the diameter (12) of the fin (24) in the tip area.

14. The screw as claimed in claim 1 wherein the cutting edge (23) of each fin (24) has a greater slope than the other edge of said fin (24).

15. A screw comprising a shank portion (20), a thread (21), a conical tip (22), and at least one cutting edge (23), wherein

(a) the thread (21) extends at least over part of the length of the shank portion and over the entire length of the tip (22) of the screw,

(b) one or more fins (24) project beyond the core diameter (1) of the shank portion (20),

(c) the cutting edge (23) is formed on said at least one or more fins (24) with the slope of the leading edge thereof being greater than the slope of the trailing edge thereof,

(d) said at least one or more fins (24) defining a smaller angle of inclination (13) than the thread (21) with the longitudinal axis of the screw, and

(e) the cutting edge (23) of said at least one or more fins extending over part of the conical tip (22) up to a finless end portion (26) of the said conical tip.