TAPERED COUNTERSINK DRILL BIT

Abstract

A tapered countersink drill bit includes at least two screwing knifes and at least one two screwing trenches and a rod body; a length of an edge of the left lateral side of each screwing knife being shorten than that of an edge of the right lateral side thereof; each screwing knife including a front drilling head; a tapered portion formed at a backside of the front drilling head; a rear drilling head formed at a backside of the tapered portion; the screwing angle of each screwing knife being identical from the front drilling head to the rear drilling head; and a screwing angle of each screwing trench being identical from the front drilling head to the rear drilling head; a width between two adjacent knifes at a front end of the rear drilling head being longer than a width between two knifes at rear ends of two rear drilling head.

Claims

1. A tapered countersink drill bit comprising: at least two screwing knifes (2) and at least two screwing trenches (3) being formed between two adjacent screwing knifes (2) of the at least two screwing knifes (2); the screwing knifes (2) and the screwing trenches (3) being extended from a front end of a polygonal rod body (14); each screwing knife being formed by a left lateral side (121A) and a right lateral side (121B) and an upper side (121) between the left lateral side (121A) and the right lateral side (121B); a length of an edge of the left lateral side (121 A) being shorten than that of an edge of the right lateral side (121B); each screwing knife (2) comprising: a front drilling head (11); a tapered portion (12) formed at a backside of the front drilling head (11); an outer diameter of a front end of the tapered portion (12) being equal to that of a rear end of the front drilling head (11); a rear drilling head (13) formed at a backside of the tapered portion (12); an outer diameter of a rear end of the tapered portion (12) being equal to that of a front end of the rear drilling head (13); an outer diameter of the front drilling head (11) being smaller than that of the rear drilling head (13); wherein the screwing angle of each screwing knife (2) is identical from the front drilling head (11) to the rear drilling head (13); and a screwing angle of each screwing trench (3) being identical from the front drilling head (11) to the rear drilling head (13); a width (3A) between two adjacent knifes (2) at the front end of the rear drilling head (13) is longer than a width (3B) between two knifes (2) of the at least two screwing knifes (2) and at the rear ends of two rear drilling head (13).

2. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a perspective view showing the first embodiment of the present invention, where three screwing knifes and three screwing trenches are shown.

[0009] FIG. 2 is a front view of FIG. 1.

[0010] FIG. 3 is a light side view of FIG. 2.

[0011] FIG. 4 is a perspective view showing the second embodiment of the present invention, where two screwing knifes and two screwing trenches are shown.

[0012] FIG. 5 is a right side view of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0013] In order that those skilled in the art can further understand the present invention, a description will be provided in the following in details. However, these descriptions and the appended drawings are only used to cause those skilled in the art to understand the objects, features, and characteristics of the present invention, but not to be used to confine the scope and spirit of the present invention defined in the appended claims.

[0014] With reference to FIGS. 1 to 3, a preferred embodiment of the present invention is illustrated. The drilling head of the present invention (having three screwing knifes and three screwing dreg removing recesses) includes:

[0015] At least two screwing knifes 2 are included and at least one two screwing trenches 3 are formed between two adjacent screwing knifes 2. The screwing knifes 2 and the screwing trenches 3 are extended from a front end of a polygonal rod body 14.

[0016] Each screwing knife is formed by a left lateral side 121A and a right lateral side 121B. A length of an edge of the left lateral side 121 A is shorten than that of an edge of the right lateral side 121B.

[0017] Each screwing knife 2 includes the following portions: [0018] A front drilling head 11 is included. [0019] A tapered portion 12 is formed at a backside of the front drilling head 11. An outer diameter of a front end of the tapered portion 12 is equal to that of a rear end of the front drilling head 11. An outer diameter of a front end of the tapered portion 12 is smaller than that of a rear end of the tapered portion 12. [0020] A rear drilling head 13 is formed at a backside of the tapered portion 12. An outer diameter of a rear end of the tapered portion 12 is equal to that of a front end of the rear drilling head 13. An outer diameter of the front drilling head 11 is smaller than that of the rear drilling head 13.

[0021] The screwing angle of each screwing knife 2 is identical from the front drilling head 11 to the rear drilling head 13; and the screwing angle of each screwing trench 3 is identical from the front drilling head 11 to the rear drilling head 13.

[0022] A width 3A between two adjacent knifes at a front end of the rear drilling head 13 is longer than a width 3B between two knifes at rear ends of two rear drilling head 13.

[0023] With reference to FIGS. 4 and 5, another embodiment of the present invention is illustrated. The drilling head of the present invention (having two screwing knifes and two screwing dreg removing recesses) includes:

[0024] Two screwing knifes 2 are included and two screwing trenches 3 are formed between two adjacent screwing knifes 2. The screwing knifes 2 and the screwing trenches 3 are extended from a front end of a polygonal rod body 14.

[0025] Each screwing knife 2 is formed by a left lateral side 121A and a right lateral side 121B. A length of an edge of the left lateral side 121 A is shorten than that of an edge of the right lateral side 121B.

[0026] Each screwing knife 2 includes the following portions:

[0027] A front drilling head 11 is included.

[0028] A tapered portion 12 is formed at a backside of the front drilling head 11. An outer diameter of a front end of the tapered portion 12 is equal to that of a rear end of the front drilling head 11. An outer diameter of a front end of the tapered portion 12 is smaller than that of a rear end of the tapered portion 12.

[0029] A rear drilling head 13 is formed at a backside of the tapered portion 12. An outer diameter of a rear end of the tapered portion 12 is equal to that of a front end of the rear drilling head 13. An outer diameter of the front drilling head 11 is smaller than that of the rear drilling head 13.

[0030] The screwing angle of each screwing knife 2 is identical from the front drilling head 11 to the rear drilling head 13; and the screwing angle of each screwing trench 3 is identical from the front drilling head 11 to the rear drilling head 13.

[0031] A width 3A between two adjacent knifes at a front end of the rear drilling head 13 is longer than a width 3B between two knifes at rear ends of two rear drilling head 13.

[0032] Therefore, the front drilling head, the tapered portion, the rear drilling head and the rod body are formed as an integral structure. The screwing knifes and screwing trenches have identical screwing angle and specific design as above mentioned so as to remove dregs easily and quickly in drilling operation.

[0033] The present invention is thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.