Wood screw

Abstract

A wood screw is disclosed herein. It comprises a screw head and a rod body integrally extended from the screw head and having a shank part and a screwing part, wherein the screwing part comprises a straight surface surrounded with a threaded section and a cutting section on which a cutting unit is formed, and wherein a root diameter of the shank part is larger than root diameters of the threaded section and the cutting section respectively, and larger than or equal to a maximum outer diameter of the cutting section defined by the cutting unit.

Claims

1. A wood screw, comprising: a screw head; and a rod body integrally extended from the screw head in an axial direction and including: a shank part having a first root diameter, and a screwing part defined by: a threaded section having a second root diameter less than the first root diameter of the shank part, and a cutting section being connected between the shank part and the threaded section and having a third root diameter less than the first root diameter of the shank part, wherein the threaded section has a tip portion at a bottom end thereof and a screw thread helically extended therearound from a juncture between the threaded section and the cutting section toward the tip portion, and wherein the cutting section further has a cutting unit disposed thereon, the cutting unit having a maximum outer diameter less than or equal to the first root diameter of the shank part.

2. The wood screw as claimed in claim 1, wherein the cutting unit comprises a plurality of screw threads disposed helically around the cutting section.

3. The wood screw as claimed in claim 2, wherein the tip portion of the threaded section is provided with a cutting slot to disconnect the screw thread around the tip portion.

4. The wood screw as claimed in claim 3, wherein a length ratio of the cutting section to the threaded section is 1:3 to 1:8.

5. The wood screw as claimed in claim 1, wherein the cutting unit comprises a plurality of cutting teeth axially disposed on the cutting section.

6. The wood screw as claimed in claim 5, wherein the tip portion of the threaded section is provided with a cutting slot to disconnect the screw thread around the tip portion.

7. The wood screw as claimed in claim 6, wherein a length ratio of the cutting section to the threaded section is 1:3 to 1:8.

8. The wood screw as claimed in claim 1, wherein the cutting unit comprises a plurality of cutting planes integrally disposed on the cutting section.

9. The wood screw as claimed in claim 8, wherein the tip portion of the threaded section is provided with a cutting slot to disconnect the screw thread around the tip portion.

10. The wood screw as claimed in claim 9, wherein a length ratio of the cutting section to the threaded section is 1:3 to 1:8.

11. The wood screw as claimed in claim 1, wherein the tip portion of the threaded section is provided with a cutting slot to disconnect the screw thread around the tip portion.

12. The wood screw as claimed in claim 11, wherein a length ratio of the cutting section to the threaded section is 1:3 to 1:8.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram showing a wood screw without a screw thread;

(2) FIG. 2 is a stereogram showing a first embodiment for a wood screw according to the present invention;

(3) FIG. 3 is a lateral view showing the first embodiment for the wood screw according to the present invention;

(4) FIG. 4 is a schematic diagram showing the first embodiment for the wood screw in use;

(5) FIG. 5 is a partial sectional view showing a cutting section of the first embodiment for the wood screw;

(6) FIG. 6 is a stereogram showing a second embodiment for a wood screw according to the present invention;

(7) FIG. 7 is a stereogram showing a third embodiment for a wood screw according to the present invention;

(8) FIG. 8 is a schematic diagram showing a prior art;

(9) FIG. 9 is a lateral view showing a prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(10) Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

(11) Referring to FIG. 1 to FIG. 3, a wood screw according to the present invention is disclosed herein. It mainly comprises a screw head (1) and a rod body (2) integrally extended from the screw head (1) in an axial direction. The rod body (2) comprises a shank part (21) of a first root diameter (a) and a screwing part (22) defined by a threaded section (221) of a second root diameter (b) and a cutting section (222) being connected between the shank part (21) and the threaded section (221) and being of a third root diameter (c). The second root diameter (b) of the threaded section (221) is less than the first root diameter (a) of the shank part (21), and the third root diameter (c) of the cutting section (222) is less than the first root diameter (a) of the shank part (21). The threaded section (221) has a tip portion (2210) at a bottom end thereof and a screw thread (2211) helically extended therearound from a juncture between the threaded section (221) and the cutting section (222) toward the tip portion (2210). The cutting section (222) has a cutting unit (2221) disposed thereon to define a maximum outer diameter (d) thereof being less than or equal to the first root diameter (a) of the shank part (21). The screw head (1) and the cutting section (222) are connected by the shank part (21). Furthermore, the first root diameter (a) of the shank part (21) is larger than or equal to the maximum outer diameter (d) of the cutting unit (2221) of the cutting section (222). A length ratio of the cutting section (222) to the threaded section (221) is 1:3 to 1:8.

(12) In actual implementation, the present invention provides various embodiments of the cutting unit (2221) of the cutting section (222) as shown in FIG. 1 to FIG. 7.

Example 1

(13) Referring to FIG. 3, a first embodiment for a wood screw according to the present invention is disclosed. The cutting unit (2221) comprises a plurality of screw threads (2221A) disposed helically around the cutting section (222) by thread rolling.

Example 2

(14) Referring to FIG. 6, a second embodiment for a wood screw according to the present invention is disclosed. The cutting unit (2221) comprises a plurality of cutting teeth (2221B) axially disposed on the cutting section (222) by clamping.

Example 3

(15) Referring to FIG. 7, a second embodiment for a wood screw according to the present invention is disclosed. The cutting unit (2221) comprises a plurality of cutting planes (2221C) integrally disposed on the cutting section (222) by forging.

(16) In a practical use as shown in FIG. 1 to FIG. 7, the tip portion (2210) of the threaded section (221) is further provided with a cutting slot (2212) to disconnect the screw thread (2211) around the tip portion (2210). The tip portion (2210) of the wood screw is pierced into an object (A) for positioning, and then the screw thread (2211) of the threaded section (221) is drilled into the object (A). In the steady positioning state, the cutting slot (2212) accelerates and assists the wood screw to cut and drill the object (A) and discharges wood shavings simultaneously. After the wood screw is gradually drilled into the object (A), the cutting unit (2221) on the cutting section (222) assists the cutting process. The cutting unit (2221) formed on the cutting section (222) has excellent cutting effect whether it is made by thread rolling, clamping or forging. When the wood screw is screwed into the object (A), the cutting unit (2221) previously cuts wood fibers of the object (A), so that a lateral resistance generated by the shank part (21) of a larger diameter screwing into the object (A) can be reduced. The design of the first root diameter (a) of the shank part (21) larger than or equal to the maximum outer diameter (d) of the cutting unit (2221) of the cutting section (222) enables the cutting unit (2221) to drill the object (A) to form a smooth inner cutting hole for correspondingly and tightly contacting the shank part (21). Accordingly, the present invention can reduce a gap between the wood screw and the object (A) by the shank part (21) tightly contacting the inner cutting hole and achieve the effects of withstanding high tensile force and shear stress.

(17) Compared with the conventional technique available now, the present invention has the following advantages:

(18) 1. The allocation of the cutting unit of the cutting section ahead of the shank part in the screw-in direction can reduce the lateral resistance of the rod body generated by the shank part of a larger diameter screwing into an object.

(19) 2. The design of the maximum outer diameter of the cutting unit of the cutting section not larger than the first root diameter of the shank part enables the cutting unit to drill the object to form a smooth inner cutting hole for correspondingly and tightly contacting the shank part. Accordingly, the present invention can reduce a gap between the wood screw and the object so as to achieve the effects of withstanding high tensile force and shear stress.