AU2005100407A4 - Lead screw of drill bit - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION INNOVATION PATENT LEAD SCREW OF DRILL BIT The following statement is a full description of this invention, including the best method of performing it known to me: TITLE: LEAD SCREW OF DRILL BIT BACKGROUND OF THE INVENTION Technical Field of the Invention The present invention is related to a lead screw of a drill bit, and more particularly, to a single point, instead of a line of sharper lead screw to improve positioning accuracy, drilling rate and chip expelling performance.

Description of the Prior Art As illustrated in Figs. 1 and 2, a drill bit 10 Oa of the prior art includes a conic lead screw 20a and a land 30a. The land 30a is comprised ofa pair of flutes 40a and a shank 50a to be secured by ajaw from a drill. The lead screw 20a of the bit 10a is usually made in a conic shape with its tip indicating a ridge 21a. A pair of blades 22a in radius opposite to each other extends from the ridge 21 a to connect to the flutes Whereas the lead screw 20a of the bit 1 Oa is made in conic shape and the drilling angle is greater than 90 degrees, extremely great resistance is encountered while the bit 10 Oa is drilling into a work piece resulting in poor drilling efficiency. The poor design of the fluted land fails to effectively expel the chips and the residual chips create even greater secondary resistance.

Upon contacting the work piece, the ridge 21 a prevents an easy positioning of the drill hole resulting in frequent errors of the target drill location.

SUMMARY OF THE INVENTION The primary purpose of the present invention is to an improved construction of a drill bit lead screw with wedge shaped sides to reduce friction between the lead screw and the work piece while increasing the cutting power of a scraping surface; blade of the scraping surface is used to drive residual chips out of the drill hole; and a point instead of a ridge shaped spur achieves precise positioning on the work piece.

The foregoing object and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts.

Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a bird's eye view of a drill bit of the prior art.

Fig. 2 is a front view of the drill bit of the prior art.

Fig. 3 is a perspective view of the present invention.

Fig. 4 is a bird's eye view of the present invention.

Fig. 5 is a front view of the present invention.

Fig. 6 is a left side view of the present invention.

Fig. 7 is a schematic view showing operation status of the fluted land of a preferred embodiment of the present invention to drive out the drill chips.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following descriptions are of exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention.

Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims.

Referring to Figs. 3, 4, 5, and 6, a drill bit 10 is essentially comprised of a cutter 20 including a lead screw 21 and a spur 22. Multiple flutes 40, two in the preferred embodiment of the present invention, in radius opposite to each other are provided below the cutter 20 and a shank 50 extends from the cutter for a proper length. Multiple surfaces, two in the preferred embodiment, each has a conic front at a slope less than 90 degrees and a waged side surface are provided on a cutter 20 of the lead screw 21. The lead screw 21 of both has a spur 22 provided at the center. One side not for cutting of the symmetric surface relates to a conic surface and another side for driving relates to a scraping surface 23. An outer side 231 larger than a land 30 is provided at the front end of the scraping surface 23, and a blade 24 is disposed to the outer side of the scraping surface 23. Both ends of the bottom of the scraping surface 23 and the land 30 are made in a fishing hook shape.

Furthermore, an inclined surface 25 disposed between the scraping surface 23 and the lead screw 21 extends from the led screw 21 to the bottom of the cutter As illustrated in Fig. 7, when the drill bit 10 enters into a work piece the spur 22 from the lead screw to the cutter 20 of the bit 10 indicating a point instead of a ridge as found with the prior art allows accurate positioning at a target drill hole 61 marked on the work piece 60. Whereas the wedge shaped side of the cutter 20 to the lead screw 21 and the larger outer side 231 at the front end of the scraping surface 23 permit greater scraping capability for the scraping surface 23. The blade 24 further improves the scraping efficiency.

Chips 62 from the work piece 60 left by the operation of the scraping surface 23 are guided through the inclined surface 25 to the rear end of the cutter where to be expelled out of the cutter 20 while those fluted lands 40 provided on the land 30 also drive the chips to the surface of the work piece The present invention by providing an improved structure of a lead screw of a drill bit including a sharper spur 21 disposed to the cutter 20, multiple symmetric surfaces each with a conic front and a wedge shaped side being provided to spur, the larger outer side 231 at the front end and the reduced scraping surface 23 at the rear end on each symmetric surface, and a point instead of a ridge spur 22 at the leader screw achieves the purposes of accurate positioning of the drill hole 61, upgraded drilling rate and chips expelling performance. Therefore, this application for a utility patent is duly filed accordingly.

It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above.

While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.

Claims (3)

1. A drill bit lead screw essentially comprised of a cutter including a lead screw and a spur; multiple flutes in radius opposite to one other being provided below the cutter; a shank extending from the cutter for a proper length; the cutter being provided with multiple symmetric surfaces each having a conic front at a slope smaller than degrees and a wedge shaped side; the center of both symmetric surfaces being integrated into one spur; one side not for cutting of the symmetric surface related to a conic surface; another side for driving related to a scraping surface; an outer side larger than a land being provided at the front end of the scraping surface; a blade being disposed to the outer side of the scraping surface; both ends of the bottom of the scraping surface and the land being made in a fishing hook shape; and an inclined surface disposed between the scraping surface and the lead screw extending from the led screw to the bottom of the cutter for expelling the residual chips.

2. The drill bit lead screw of Claim 1, wherein the shank of the drill bit is provided with a non-circular section.

3. The drill bit lead screw of Claim 1, wherein slip-proof teeth are provided on the shank.