Coupling mechanism for cutting tool

Patent metadata

Field	Value
Publication number	US-9643262-B2
Application number	US-201414273456-A
Country	US
Kind code	B2
Filing date	May 8, 2014
Priority date	Jul 25, 2013
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A rotary cutting tool including a cutter member having an axial forward end and an axial rearward end. A cutting region is at the axial forward end of the cutter member, and a male threaded portion is adjacent the axial rearward end of the cutter member. A shank member has an axial forward end and a shank bore opening at the axial forward end. The shank bore has an axial shank bore length. The shank bore contains a female threaded portion and an axial rearward shank bore portion axially rearward of the female threaded portion. The axial rearward shank bore portion has a terminal end. When the male threaded portion of the cutter member fully engages the female threaded portion of the shank member, the axial rearward end of the cutter member being spaced a first distance axially forward of the terminal end of the axial rearward shank bore portion.

First claim

What is claimed is:

1. A rotary cutting tool comprising:
a cutter member having an axial forward end and an axial rearward end, a cutting region at the axial forward end of the cutter member, and a male threaded portion adjacent the axial rearward end of the cutter member;
a shank member having an axial forward end and a shank bore opening at the axial forward end, the shank bore having an axial shank bore length, the shank bore containing a female threaded portion and an axial rearward shank bore portion axially rearward of the female threaded portion, and the axial rearward shank bore portion having a terminal end;
the male threaded portion including a number of threads disposed at a first pitch and the female threaded portion including a number of threads disposed at a second pitch different than the first pitch;
the male threaded portion including a thread closest to the axial forward end;
wherein the cutter includes an axial stop shoulder and the shank member includes an axial stop surface; and
in an assembled state:
the cutter member and the shank member are selectively coupled via threaded engagement of the male threaded portion and the female threaded portion, wherein the male threaded portion of the cutter member fully engages the female threaded portion of the shank member;
the axial stop shoulder of the cutter abuts the axial stop surface of the shank member; and
the axial rearward end of the cutter member is spaced at a first distance axially forward of the terminal end of the axial rearward shank bore portion;
whereby stress concentration at the thread closest to the axial forward end of the cutter member is avoided.

2. The rotary cutting tool according to claim 1 , wherein the cutter member comprises:
an axial forward radial aligner portion axially forward of the male threaded portion;
wherein the axial stop shoulder is disposed axially forward of the axial forward radial aligner portion; and
an arcuate fillet joining the axial forward radial aligner portion and the axial stop shoulder;
the arcuate fillet having a radius wherein the ratio of the radius of the arcuate fillet to a maximum diameter of the cutting region ranges between about 0.02 and about 0.04.

3. The rotary cutting tool according to claim 2 wherein the ratio of the radius of the arcuate fillet to the maximum diameter of the cutting region ranges between about 0.025 and about 0.035.

4. The rotary cutting tool according to claim 2 wherein the axial forward radial aligner portion has an axial rear end, the axial stop shoulder is disposed at a distance from the axial rear end of the axial forward radial aligner portion, and the ratio of the distance to the maximum diameter of the cutting region ranges between about 0.15 to about 0.25.

5. The rotary cutting tool according to claim 4 wherein the ratio of the distance to the maximum diameter of the cutting region is greater than or equal to 0.18.

6. The rotary cutting tool according to claim 2 wherein the axial stop shoulder is disposed at an angle between about −3 degrees and about +3 degrees relative to a reference line perpendicular to a central longitudinal axis of the cutter member.

7. The rotary cutting tool according to claim 1 wherein an axial forward radial aligner portion has an outward facing circumferential surface disposed at an angle relative to a central longitudinal axis of the cutter member, and the angle ranges between about 1 degree and about 7 degrees.

8. The rotary cutting tool according to claim 7 wherein:
each of the male threads has a depth, a root and a distal surface; the distal surfaces of the male threads being disposed at an angle relative to the central longitudinal axis of the cutter member, which angle ranges between about 1 degree and about 3 degrees; the roots of the male threads being disposed at an angle relative to the central longitudinal axis of the cutter member, which angle ranges between about 1 degree and about 3 degrees; wherein the ratio of the male thread depth to a maximum diameter of the cutting region ranges between about 0.03 and about 0.06; and
wherein the angle at which the outward facing circumferential surface is disposed relative to the central longitudinal axis of the cutter member is greater than or equal to the angle at which the distal surfaces of the male threads are disposed relative to the central longitudinal axis of the cutter member.

9. The rotary cutting tool according to claim 8 wherein the angle at which outward facing circumferential surface is relative to the central longitudinal axis of the cutter member is greater than the angle at which the distal surfaces of the male threads are disposed relative to the central longitudinal axis of the cutter member.

10. The rotary cutting tool according to claim 1 wherein the male threaded portion has a maximum radial distance from thread root to a centerline, and the ratio of the maximum radial distance from the thread root to the centerline to a maximum diameter of the cutting region ranges between about 0.30 and about 0.35.

11. The rotary cutting according to claim 1 wherein a difference between a maximum diameter of an axial forward radial aligner portion and the maximum diameter of the axial forwardmost shank bore portion ranges between about 0.015 and about 0.035 of the maximum diameter of the cutting region.

12. The rotary cutting tool according to claim 11 wherein the difference between a maximum diameter of the axial forward radial aligner portion and the maximum diameter of the axial forwardmost shank bore portion is about 0.025 of the maximum diameter of the cutting region.

13. The rotary cutting tool according to claim 1 wherein the male threaded portion comprises at least five male threads.

14. The rotary cutting tool according to claim 1 wherein the female thread pitch is greater than the male thread pitch.

15. The rotary cutting tool according to claim 14 wherein the ratio of the male thread pitch to a maximum diameter of the cutting region is between about 0.12 and about 0.18, and the ratio of the female thread pitch to the maximum diameter of the cutting region is between about 0.12 and about 0.18.

16. The rotary cutting tool according to claim 1 , wherein: the shank bore has a length, the cutter member has a flat axial stop shoulder, and a distance is defined between the axial stop shoulder and the axial rearward end of the cutter member; the length of the shank bore being greater than the distance between the axial stop shoulder and the axial rearward end of the cutter member; the ratio of the distance between the axial stop shoulder and the axial rearward end of the cutter member to a maximum diameter of the cutting region is between about 0.9 and about 1.3.

17. A cutter member for use in conjunction with a shank member wherein the shank member has an axial forward end and a shank bore opening at the axial forward end, the shank bore having an axial shank bore length, the shank bore containing a female threaded portion and an axial rearward shank bore portion axially rearward of the female threaded portion, the shank member further including an axial stop surface, and the axial rearward shank bore portion having a terminal end, the cutter member comprising:
an axial forward end and an axial rearward end, a cutting region at the axial forward end of the cutter member, and a male threaded portion adjacent the axial rearward end of the cutter member;
an axial forward radial aligner portion axially forward of the male threaded portion, and a flat axial stop shoulder axially forward of the axial forward radial a

Assignees

• Kennametal Inc

Inventors

• Frota De Souza Ruy
• Sharivker Leonid B
• Boulakhov Sergei
• Gey Christoph
• Harush Yosi
• Bookheimer Alan
• Levy Uzi
• George Stephen M

Classifications

• B23B2251/02

  Connections between shanks and removable cutting heads · CPC title

• B23C2240/32

  Connections using screw threads · CPC title

• Y10T408/907

  including detailed shank · CPC title

• F16B39/30

  Locking exclusively by special shape of the screw-thread · CPC title

• Y10T407/1906

  including holder [i.e., head] having seat for inserted tool · CPC title