US 12,269,101 B1 · Twist drill

Abstract

The present invention provides a twist drill. A cone portion is provided at a front end of the operating portion, and an exterior surface of the operating portion is provided with a spiral flute for shunting cutting chips. The exterior surface of the cone portion is provided with a plurality of composite cutting blade groups which are sequentially enlarged in diameter from the front end to the rear end of the cone portion. The cone portion is provided with a top blade on the tip. In use, the top blade is used for positioning, and the cutting process is carried out by the top blade and the composite cutting blade groups.

Claims26

Dependent claims

A twist drill comprising:

a shank portion;
an operating portion axially fixed to the shank portion, the operating portion comprising a cylinder portion, a cone portion axially fixed to the cylinder portion, and a spiral flute having a sidewall and being formed into an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the shank portion axially fixed to the cylinder portion opposite the cone portion;
a plurality of four or more composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, and diameters of the composite cutting blade groups sequentially increase from the front end to the rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion,
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

11 more elements

A twist drill comprising:

a shank portion;
an operating portion axially fixed to the shank portion, the operating portion comprising a cylinder portion, a cone portion axially fixed to the cylinder portion, said cone portion having an acute effective apex angle, and a spiral flute having a sidewall and being formed into an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the shank portion axially fixed to the cylinder portion opposite the cone portion;
a plurality of composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, and diameters of the composite cutting blade groups sequentially increase from the front end to the rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion,
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

11 more elements

A twist drill, comprising:

an operating portion comprising a cone portion and a cylinder portion axially fixed to the cone portion;
a shank portion axially fixed to the cylinder portion opposite the cone portion;
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall;
a plurality of four or more composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion,
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion;
and
wherein a diameter of a composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

15 more elements

A twist drill comprising:

an operating portion comprising a cone portion and a cylinder portion axially fixed to the cone portion said cone portion having an acute effective apex angle;
a shank portion axially fixed to the cylinder portion opposite the cone portion;
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall;
a plurality of composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion,
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion;
and
wherein a diameter of a composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

15 more elements

A twist drill, comprising:

an operating portion comprising a cone portion and a cylinder portion axially fixed to the cone portion;
a shank portion axially fixed to the cylinder portion opposite the cone portion;
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall;
a plurality of four or more composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
a top blade provided on the front end of the cone portion,
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion;
and
wherein a diameter of a last composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

14 more elements

A twist drill comprising:

an operating portion comprising a cone portion and a cylinder portion axially fixed to the cone portion said cone portion having an acute effective apex angle;
a shank portion axially fixed to the cylinder portion opposite the cone portion;
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall;
a plurality of composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
a top blade provided on the front end of the cone portion;
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion;
and each of the plurality of composite cutting blade groups is configured to cut fine chips and the spiral flute is configured to shunt the finer chips;
and
wherein a diameter of a last composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

15 more elements

A method for improving centering accuracy of a twist drill when drilling a drill hole in a workpiece using multistage centering and using both a cone portion and a cylinder portion, the method comprising:

providing the twist drill comprising:
a shank portion;
an operating portion axially fixed to the shank portion, the operating portion comprising the cylinder portion and the cone portion axially fixed to the cylinder portion and a spiral flute having a sidewall and being formed into an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the shank portion axially fixed to the cylinder portion opposite the cone portion;
a plurality of four or more composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, and diameters of the composite cutting blade groups sequentially increase from the front end to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step surface and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion;
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
the diameter of the last composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to the cylinder portion diameter;
and the cylinder portion is longer than the cone portion;
positioning the twist drill atop the workpiece;
applying a torque and an axial drilling force to the twist drill;
cutting the workpiece with the top blade to create a drill hole in the workpiece;
continuing cutting the workpiece using one or more of the plurality of composite cutting blade groups situated closest to the front end;
and
continuing cutting the workpiece using all of the plurality of composite cutting blade groups, when a portion of the cylinder portion is also within the workpiece.

19 more elements

A method for improving centering accuracy of a twist drill when drilling a drill hole in a workpiece using multistage centering and using both a cone portion, said cone portion having an acute effective apex angle;

and a cylinder portion, the method comprising:
providing the twist drill comprising:
a shank portion;
an operating portion axially fixed to the shank portion, the operating portion comprising the cylinder portion and the cone portion axially fixed to the cylinder portion and a spiral flute having a sidewall and being formed into an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the shank portion axially fixed to the cylinder portion opposite the cone portion;
a plurality of composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, and diameters of the composite cutting blade groups sequentially increase from the front end to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step surface and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion;
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
the diameter of the last composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to the cylinder portion diameter;
and the cylinder portion is longer than the cone portion;
positioning the twist drill atop the workpiece;
applying a torque and an axial drilling force to the twist drill;
cutting the workpiece with the top blade to create a drill hole in the workpiece;
continuing cutting the workpiece using one or more of the plurality of composite cutting blade groups situated closest to the front end;
and
continuing cutting the workpiece using all of the plurality of composite cutting blade groups, when a portion of the cylinder portion is also within the workpiece.

20 more elements

providing the twist drill, comprising:
an operating portion comprising
the cone portion,
the cylinder portion axially fixed to the cone portion,
a shank portion axially fixed to the cylinder portion opposite the cone portion,
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall, and
a plurality of four or more composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion;
each of the plurality of composite cutting blade groups comprising:
a first step surface,
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute,
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute, and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion;
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
and a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion, and
wherein a diameter of a composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion;
positioning the twist drill atop the workpiece;
applying a torque and an axial drilling force to the twist drill;
cutting the workpiece with the top blade to create a drill hole in the workpiece;
continuing cutting the workpiece using one or more of the plurality of composite cutting blade groups situated closest to the front end;
and
continuing cutting the workpiece using all of the plurality of composite cutting blade groups, when a portion of the cylinder portion is also within the workpiece.

23 more elements

providing the twist drill, comprising:
an operating portion comprising
the cone portion having an acute effective apex angle,
the cylinder portion axially fixed to the cone portion,
a shank portion axially fixed to the cylinder portion opposite the cone portion,
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall, and
a plurality of composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion;
each of the plurality of composite cutting blade groups comprising:
a first step surface,
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute,
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute, and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion;
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
and a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion, and
wherein a diameter of a composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion;
positioning the twist drill atop the workpiece;
applying a torque and an axial drilling force to the twist drill;
cutting the workpiece with the top blade to create a drill hole in the workpiece;
continuing cutting the workpiece using one or more of the plurality of composite cutting blade groups situated closest to the front end;
and
continuing cutting the workpiece using all of the plurality of composite cutting blade groups, when a portion of the cylinder portion is also within the workpiece.

23 more elements

Dependencies are inferred from the claim text.

Facts

Application

18/391,429Filed 20 Dec 2023 · continuation

Priority

14 Feb 2016

Granted

8 Apr 2025

Term ends

Not estimatedThe source records don’t support an estimate.

Classification6 codes

B23B 51/02
Tools for drilling machines: twist drills
B23B 51/0081
Tools for drilling machines: conical drills
B23B 51/009
Tools for drilling machines: stepped drills
B23B 2251/04
Details of tools for drilling machines: angles, e.g. cutting angles

Family

PCT/CN2016/073767Parent of this continuation-in-part · filed 14 Feb 2016

Application15/847,900Parent of this continuation-in-part · filed 19 Dec 2017

Application16/699,089Parent of this continuation · filed 28 Nov 2019

Application17/094,786Parent of this continuation · filed 10 Nov 2020

Application17/321,373Parent of this continuation · filed 14 May 2021

US 11,007,584 B2Parent of this continuation · filed 18 May 2021

US 11,007,583 B2Parent of this continuation · filed 18 May 2021

Application18/095,119Parent of this continuation · filed 10 Jan 2023

US 11,554,424 B1Parent of this continuation · filed 17 Jan 2023

US 11,865,627 B1Parent of this continuation

Application16/699,089Parent of this continuation-in-part

US 2018/0133808 A1Published application

US 2020/0094331 A1Published application

US 2021/0060662 A1Published application

US 12,269,101 B1This patent

From the US filing history. Foreign family members aren’t listed.

Abstract

Claims26

Dependent claims

A twist drill comprising:

a shank portion;
an operating portion axially fixed to the shank portion, the operating portion comprising a cylinder portion, a cone portion axially fixed to the cylinder portion, and a spiral flute having a sidewall and being formed into an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the shank portion axially fixed to the cylinder portion opposite the cone portion;
a plurality of four or more composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, and diameters of the composite cutting blade groups sequentially increase from the front end to the rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion,
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

11 more elements

A twist drill comprising:

a shank portion;
an operating portion axially fixed to the shank portion, the operating portion comprising a cylinder portion, a cone portion axially fixed to the cylinder portion, said cone portion having an acute effective apex angle, and a spiral flute having a sidewall and being formed into an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the shank portion axially fixed to the cylinder portion opposite the cone portion;
a plurality of composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, and diameters of the composite cutting blade groups sequentially increase from the front end to the rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion,
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

11 more elements

A twist drill, comprising:

an operating portion comprising a cone portion and a cylinder portion axially fixed to the cone portion;
a shank portion axially fixed to the cylinder portion opposite the cone portion;
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall;
a plurality of four or more composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion,
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion;
and
wherein a diameter of a composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

15 more elements

A twist drill comprising:

an operating portion comprising a cone portion and a cylinder portion axially fixed to the cone portion said cone portion having an acute effective apex angle;
a shank portion axially fixed to the cylinder portion opposite the cone portion;
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall;
a plurality of composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion,
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion;
and
wherein a diameter of a composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

15 more elements

A twist drill, comprising:

an operating portion comprising a cone portion and a cylinder portion axially fixed to the cone portion;
a shank portion axially fixed to the cylinder portion opposite the cone portion;
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall;
a plurality of four or more composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
a top blade provided on the front end of the cone portion,
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion;
and
wherein a diameter of a last composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

14 more elements

A twist drill comprising:

an operating portion comprising a cone portion and a cylinder portion axially fixed to the cone portion said cone portion having an acute effective apex angle;
a shank portion axially fixed to the cylinder portion opposite the cone portion;
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall;
a plurality of composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
a top blade provided on the front end of the cone portion;
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion;
and each of the plurality of composite cutting blade groups is configured to cut fine chips and the spiral flute is configured to shunt the finer chips;
and
wherein a diameter of a last composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion.

15 more elements

providing the twist drill comprising:
a shank portion;
an operating portion axially fixed to the shank portion, the operating portion comprising the cylinder portion and the cone portion axially fixed to the cylinder portion and a spiral flute having a sidewall and being formed into an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the shank portion axially fixed to the cylinder portion opposite the cone portion;
a plurality of four or more composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, and diameters of the composite cutting blade groups sequentially increase from the front end to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step surface and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion;
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
the diameter of the last composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to the cylinder portion diameter;
and the cylinder portion is longer than the cone portion;
positioning the twist drill atop the workpiece;
applying a torque and an axial drilling force to the twist drill;
cutting the workpiece with the top blade to create a drill hole in the workpiece;
continuing cutting the workpiece using one or more of the plurality of composite cutting blade groups situated closest to the front end;
and
continuing cutting the workpiece using all of the plurality of composite cutting blade groups, when a portion of the cylinder portion is also within the workpiece.

19 more elements

and a cylinder portion, the method comprising:
providing the twist drill comprising:
a shank portion;
an operating portion axially fixed to the shank portion, the operating portion comprising the cylinder portion and the cone portion axially fixed to the cylinder portion and a spiral flute having a sidewall and being formed into an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the shank portion axially fixed to the cylinder portion opposite the cone portion;
a plurality of composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion, and diameters of the composite cutting blade groups sequentially increase from the front end to a rear end of the cone portion, each of the plurality of composite cutting blade groups comprising:
a first step surface;
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute;
a minor cutting edge defined by an intersection of the second step surface and the sidewall of the spiral flute;
and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion;
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
the diameter of the last composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to the cylinder portion diameter;
and the cylinder portion is longer than the cone portion;
positioning the twist drill atop the workpiece;
applying a torque and an axial drilling force to the twist drill;
cutting the workpiece with the top blade to create a drill hole in the workpiece;
continuing cutting the workpiece using one or more of the plurality of composite cutting blade groups situated closest to the front end;
and
continuing cutting the workpiece using all of the plurality of composite cutting blade groups, when a portion of the cylinder portion is also within the workpiece.

20 more elements

providing the twist drill, comprising:
an operating portion comprising
the cone portion,
the cylinder portion axially fixed to the cone portion,
a shank portion axially fixed to the cylinder portion opposite the cone portion,
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall, and
a plurality of four or more composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion;
each of the plurality of composite cutting blade groups comprising:
a first step surface,
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute,
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute, and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion;
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
and a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion, and
wherein a diameter of a composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion;
positioning the twist drill atop the workpiece;
applying a torque and an axial drilling force to the twist drill;
cutting the workpiece with the top blade to create a drill hole in the workpiece;
continuing cutting the workpiece using one or more of the plurality of composite cutting blade groups situated closest to the front end;
and
continuing cutting the workpiece using all of the plurality of composite cutting blade groups, when a portion of the cylinder portion is also within the workpiece.

23 more elements

providing the twist drill, comprising:
an operating portion comprising
the cone portion having an acute effective apex angle,
the cylinder portion axially fixed to the cone portion,
a shank portion axially fixed to the cylinder portion opposite the cone portion,
a spiral flute formed on an exterior surface of the operating portion extending from a front end of the cone portion and at least partway up the cylinder portion, the spiral flute having a sidewall, and
a plurality of composite cutting blade groups formed sequentially on a cone portion exterior from the front end of the cone portion to a rear end of the cone portion;
each of the plurality of composite cutting blade groups comprising:
a first step surface,
a second step surface adjacent to the first step surface,
a major cutting edge defined by an intersection of the first step surface and the sidewall of the spiral flute,
a minor cutting edge defined by an intersection of the second step and the sidewall of the spiral flute, and
a cutting tip defined by an intersection of the major cutting edge, the minor cutting edge, and the sidewall of the spiral flute;
and
a top blade provided on the front end of the cone portion;
wherein a plurality of said cutting tips forms a spiral pattern on the cone portion exterior;
and a diameter of each of the plurality of composite cutting blade groups increases sequentially from the front end of the cone portion to the rear end of the cone portion, and
wherein a diameter of a composite cutting blade group located at the rear end of the cone portion immediately adjacent to the cylinder portion is less than or equal to a diameter of the cylinder portion;
the second step surface of at least one composite cutting blade group is immediately adjacent to the first step surface of a next composite cutting blade group;
and the cylinder portion is longer than the cone portion;
positioning the twist drill atop the workpiece;
applying a torque and an axial drilling force to the twist drill;
cutting the workpiece with the top blade to create a drill hole in the workpiece;
continuing cutting the workpiece using one or more of the plurality of composite cutting blade groups situated closest to the front end;
and
continuing cutting the workpiece using all of the plurality of composite cutting blade groups, when a portion of the cylinder portion is also within the workpiece.

23 more elements

Dependencies are inferred from the claim text.

Twist drill

Life of this patent

Abstract

Claims26

Twist drill

Life of this patent

Abstract

Claims26