SCREW

Abstract

A screw includes a positioning member defined on inclined cutting planes of a drilling portion of the screw for allowing a cutting edge constructed at a convergence of the cutting planes to cut stably and efficiently. A main threaded section formed on a shank of the screw is extended to connect with one end of the cutting edge. The positioning member helps the screw fixedly stand on an object. The cutting edge and the cutting planes allow cutting debris to be swiftly and smoothly extruded therefrom into the main threaded section for avoiding the accumulation of considerable cutting debris. Thereby, the screwing resistance is reduced and the drilling speed is promoted. Preferably, the fastened screw is firmly sunk in the object, and the fastening operation is completed successfully.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This invention is a continuation of the U.S. patent application Ser. No. 13/222,071, filed on Aug. 31, 2011, of which the subject matter is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fastener design, particularly to a screw capable of reducing the screwing resistance and increasing the drilling speed.

2. Description of the Related Art

Referring to FIG. 1, a conventional screw 1 comprises a shank portion 11, a head portion 12 disposed at one end of the shank portion 11, a drilling portion 13 disposed at the other end of the shank portion 11, and a plurality of threaded units 14 spirally disposed around the shank portion 11. Wherein, the drilling portion 13 is formed into a tapered end. Thus, the screw 1 directly enters an object 2 via the drilling of the tapered drilling portion 13, and the following threaded units 14 continue entering the object 2 so as to achieve a fastening effect.

The screw 1 might be smoothly fastened into the object 2 by using the drilling portion 13 to pierce the object 2. However, in practice, the object 2 is forcedly pierced by the tapered drilling portion 13. Thus, fibers of the object 2 are difficult to be severed efficiently. That is to say, the fibers are just simply pushed and thrust by the tapered drilling portion 13, so the screw 1 would be easily impeded by debris resulted from the object 2 while drilling. As a result, the debris can not be timely expelled, and the heaped debris incurs an increasing resistance on the screw 1. Therefore, the operation of fastening the screw 1 is influenced.

Referring to FIG. 2, the upright screw 1 in the object 2 might be subject to rustiness when the head portion 12 is waterlogged. Therefore, in the practical application, the screw 1 is inclinedly drilled into the object 2. Herein, if the cutting debris can not be timely expelled, the head portion 12 is easily protruded from the surface of the object 2 after screwing. Such abnormal operation is unbeneficial for further fastening and processing. Therefore, the screw 1 needs improvements.

SUMMARY OF THE INVENTION

It is therefore the purpose of this invention to provide a screw that is able to timely expel debris, efficiently decrease the screwing resistance, and preferably promote the screwing speed so as to allow the screw to be sunk in an object firmly.

The screw in accordance with the present invention comprises a shank portion, a head portion disposed at one end of the shank portion, a drilling portion disposed at the other end of the shank portion, and a main threaded section with a plurality of threaded units spirally disposed around the shank portion. Two inclined cutting planes are formed on the drilling portion and are connected at a cutting edge. The cutting edge extendedly defines two ends. A positioning member is defined on the cutting planes of the drilling portion for stabilizing the cutting edge to execute cutting. The main threaded section extends toward the cutting edge and connects to one end of the cutting edge for communicating the main threaded section with the drilling portion.

Preferably, a threaded section with a plurality of auxiliary threaded units is disposed around the shank portion, the auxiliary threaded units are disposed between the threaded units of the main threaded section, and a first diameter of the auxiliary threaded units is smaller than a second diameter of the threaded units.

Preferably, a plurality of indented units can be defined on the auxiliary threaded units, and a plurality of slots can be defined on part of the threaded units.

Preferably, the positioning member is integrally protruded outwards from the cutting planes to form a pointed unit.

Preferably, the pointed unit is formed by a plurality of inclined walls to structure a pyramid.

Preferably, the pointed unit is structured into a cone.

Preferably, the positioning member is formed by a plurality of inclined walls that are recessed from the cutting planes, thereby forming a valley on the cutting planes. Each inclined wall and the cutting edge are converged at one point.

Accordingly, the positioning member helps the cutting edge stably stand on a screwing object, which allows the cutting edge to provide a scraping effect at the time of drilling. Further, the cutting planes guide cutting debris to smoothly enter the channel between the threaded units so as to rapidly expel the cutting debris therefrom. Thereby, a large amount of cutting debris is not accumulative in the vacancy of the threaded units, so the screwing resistance could be decreased, and the screwing speed could be increased. Moreover, the screw is favorably sunk in the object for facilitating the further operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a conventional screw;

FIG. 2 is a schematic view showing the conventional screw;

FIG. 3 is a schematic view showing a first preferred embodiment of the present invention;

FIG. 4 is an end view of FIG. 3;

FIG. 5 is a partial schematic view showing a second preferred embodiment of the present invention;

FIG. 6 is a schematic view showing the first preferred embodiment of the present invention in screwing;

FIG. 7 is a schematic view showing a third preferred embodiment of the present invention;

FIG. 8 is an end view of FIG. 7;

FIG. 9 is a schematic view showing a fourth preferred embodiment of the present invention;

FIG. 10 is a schematic view showing a fifth preferred embodiment the present invention;

FIG. 11 is a schematic view showing a sixth preferred embodiment of the present invention; and

FIG. 12 is a schematic view showing a seventh preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

Referring to FIG. 3, a first preferred embodiment of the present invention is shown. In order to show the features of the screw 3 clearly, the screw 3 in this figure is presented by one side. A screw 3 comprises a shank portion 31, a head portion 32 disposed at one end of the shank portion 31, a drilling portion 33 disposed at the other end of the shank portion 31, and a main threaded section 34 with a plurality of threaded units spirally disposed around the shank portion 31. Wherein, a channel 341 is defined amid the threaded units 34. Further referring to FIG. 4, two inclined cutting planes 331 are convergently formed on the drilling portion 33, and a cutting edge 332 is formed on the convergence of the cutting planes 331. The cutting edge 332 extendedly defines two ends 333. Additionally, a positioning member 334 is defined on the cutting planes 331 to provide the screw 3 a positioning effect on an object while drilling. Herein, the positioning member 334 is integrally protruded outwards from the cutting planes 331 to structure a pointed unit . In this embodiment, the pointed unit of the positioning member 334 is preferably assembled by a plurality of inclined walls 334′ protruded from the cutting planes 331, for example, there are four inclined walls 334′ forming a square pyramid as illustrated. Alternatively, the pointed unit of the positioning member 334 can be structured by a cone protruded from the cutting planes 331. For example, an oblate cone could be especially defined on the cutting planes 331 as preferably shown in FIG. 5. Continuingly, the cutting edge 332 preferably scrapes the object while drilling. Moreover, while the main threaded section 34 around the shank portion 31 extends to the cutting edge 332 and connects to one end 333 of the cutting edge 332, the channel 341 is formed as an intercommunicated channel amid the threaded units of the main threaded section 34 for being communicated with the drilling portion 33.

Referring to FIG. 6, in operation, the e positioning member 334 is propped up against an object 4 (e.g. a plywood) for achieving a stable positioning effect. Thereby, the head portion 32 is imparted by a screwing torque for driving the drilling portion 33 to rotate. At the time of contacting the cutting edge 332 with the object 4, a gradual screwing effect is brought about, and the cutting edge 332 is applied to cut and sever the object 4 with a sharp progression. By means of the connection of the main threaded section 34 to one end 333 of the cutting edge 332 and the arrangement of the inclined cutting planes 331, the cutting debris generated in the drilling step is conducted to enter from the cutting planes 331 of the drilling portion 33 into the channel 341 among the threaded units of the main threaded section 34 directly so that the cutting debris is promptly removed through the channel 341 to prevent a large amount of cutting debris from obstructing and compressing the vacancy between the screw 3 and the object 4. Therefore, the present invention facilitates a reduced fastening resistance and allows the screw 3 to provide a stable fastening effect when the screw 3 is gradually drilled for being sunk into the object 4. Favorably, however the screw 3 is positioned upright or slantwise, a firm and stable positioning effect of the screw 3 in the object 4 is ensured, and the screw 3 is sunk in the object 4 without exposing to the outside. As result, the object 4 has a smooth appearance for benefiting a further processing.

Referring to FIG. 7 and FIG. 8, a third preferred embodiment is shown. In order to show the features of the screw 3 clearly, the screw 3 in these figures is shown by another sides. Wherein, the screw 3 still comprises the shank portion 31, the head portion 32, the drilling portion 33, and the main threaded section 34 with threaded units. Differently, the positioning member 334 is assembled by a plurality of inclined walls 334′ that are recessed on the cutting planes 331, thereby forming a valley 335 thereon. Additionally, a point P is defined on the convergence of each inclined wall 334′ and the cutting edge 332 to give the flat cutting edge 332 and the cutting planes 331 a support on the object (not shown) at the time of drilling and obtain an accurate and stable positioning effect, Further, by the cooperation of the cutting edge 332 and the threaded units of the main threaded section 34, the screw 3 could be speedily drilled in the object by the efficient cutting and removal of debris which facilitates a decrease in the screwing resistance. As a result, the screw 3 is able to provide a speedy fastening effect and is firmly sunk into the object after drilling.

Referring to FIG. 9 and FIG. 10, a fourth and a fifth preferred embodiment are shown. The screw 3 still comprises a shank portion 31, a head portion 32, a drilling portion 33, and a main threaded section 34 with a plurality of threaded units. The correlation of elements and functions are the same as those of previous preferred embodiments and herein are omitted. In this embodiment, a threaded section A is further defined on the shank portion 31. Wherein, the threaded section A comprises a plurality of auxiliary threaded units 35 that are spirally disposed between. the threaded units 34. Additionally, a first diameter r2 of the auxiliary threaded units 35 is smaller than a second diameter r1 of the threaded units of the main threaded section 34. Accordingly, the screw 3 attains a high-low threaded arrangement by setting the auxiliary threaded units 35 of the threaded section A between the threaded units of the main threaded section 34. Such high-low threaded units are beneficial to accelerate the speed of debris removal, decrease the drilling resistance, and prevent the large amount of accumulation of debris. Favorably, the screw 3 is smoothly and speedily fastened into the object and is firmly sunk. into the object after the fastening operation.

Referring to FIG. 11 and FIG. 12, a sixth and a seventh preferred embodiment of the present invention are shown. This embodiment is characterized in that a plurality of indented units 351 can be defined on the auxiliary threaded unit 35. Further, a plurality of slots 342 are formed on part of the threaded units of the main threaded section 34. Accordingly, the slots 342 and the indented units 351 assist the drilling portion 33 of the screw 3 in increasing the drilling and cutting effect and promoting the removal of debris, thereby allowing the drilling friction and the resistance to be largely reduced and increasing the fastening efficiency. The screw 3 is sunk in the object 4 after the drilling step, and a firm and stationary fastening performance is achieved.

To sum up, the present invention takes advantage of the positioning member to help a stable positioning effect at the beginning of the drilling operation, thereby benefiting a stable cutting step. Then the two cutting planes converged at a cutting edge and the connection of the main threaded section to one end of the cutting edge speedily remove the cutting debris generated in the drilling step and avoid a large amount of accumulation of debris within the object. Accordingly, the drilling resistance is decreased, and the drilling speed is increased. Thus, the screw of the present invention could be firmly and smoothly sunk in the object for benefiting a further processing.

While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.

Claims

1. A screw comprising a shank portion, a head portion disposed at one end of said shank portion, a drilling portion disposed at the other end of said shank portion, and a main threaded section with a plurality of threaded units spirally disposed around said shank portion;

wherein said drilling portion has two inclined cutting planes which are connected at a cutting edge, said cutting edge extendedly defining two ends, a positioning member being defined on said cutting planes of said drilling portion for dividing said cutting edge and stabilizing said cutting edge to execute cutting; said main threaded section extending toward said cutting edge and connecting to one end of said cutting edge for communicating said main threaded section with said drilling portion.

2. The screw as claimed in claim 1, wherein, a threaded section including a plurality of auxiliary threaded units is disposed around said shank portion and disposed between said threaded units of said main threaded section, and a first diameter of said auxiliary threaded units is smaller than a second diameter of said threaded units of said main threaded section.

3. The screw as claimed in claim 2, wherein, a plurality of indented units are defined on said auxiliary threaded units, and a plurality of slots are defined on part of said threaded units of said main threaded section.

4. The screw as claimed in claim 1, wherein said positioning member is integrally protruded outwards from said cutting planes to form a pointed unit.

5. The screw as claimed in claim 2, wherein said positioning member is integrally protruded outwards from said cutting planes to form a pointed unit.

6. The screw as claimed in claim 3, wherein said positioning member is integrally protruded outwards from said cutting planes to form a pointed unit.

7. The screw as claimed in claim 4, wherein, said pointed unit is formed by a plurality of inclined walls to structure a pyramid.

8. The screw as claimed in claim 5, wherein, said pointed unit is formed by a plurality of inclined walls to structure a pyramid.

9. The screw as claimed in claim 6, wherein, said pointed unit is formed by a plurality of inclined walls to structure a pyramid.

10. The screw as claimed in claim 4, wherein, said pointed unit is structured into a cone.

11. The screw as claimed in claim 5, wherein, said pointed unit is structured into a cone.

12. The screw as claimed in claim 6, wherein, said pointed unit is structured into a cone.

13. The screw as claimed in claim 1, wherein, said positioning member is formed by a plurality of inclined walls that are recessed inwards from said cutting planes for forming a valley on said cutting planes, and each of said inclined walls and said cutting edge are converged at a point.

14. The screw as claimed in claim 2, wherein, said positioning member is formed by a plurality of inclined walls that are recessed inwards from said cutting planes for forming a valley on said cutting planes, and each of said inclined walls and said cutting edge are converged at a point.

15. The screw as claimed in claim 3, wherein, said positioning member is formed by a plurality of inclined wails that are recessed inwards from said cutting planes for forming a valley on said cutting planes, and each of said inclined walls and said cutting edge are converged at a point.