Replaceable cutting head having back-tapered conical external thread and rotary cutting tool

Patent metadata

Field	Value
Publication number	US-11446746-B2
Application number	US-201916708565-A
Country	US
Kind code	B2
Filing date	Dec 10, 2019
Priority date	Dec 10, 2019
Publication date	Sep 20, 2022
Grant date	Sep 20, 2022

Abstract

A rotary cutting tool includes a replaceable cutting head and a tool holder. The replaceable cutting head includes a forward cutting portion and a rearward mounting portion. The mounting portion includes a male coupling member that includes a back-tapered conical external thread. The tool holder includes a female coupling member that includes an internal thread. When the rotary cutting tool is in a locked position, the external thread is threadingly engaged with the internal thread.

First claim

What is claimed is:

1. A replaceable cutting head ( 22 ), having a head longitudinal axis (A) extending in a forward (D F ) to rearward direction (D R ), comprising
a forward portion forming a cutting portion ( 26 ); and
a rearward portion forming a mounting portion ( 28 ), the mounting portion ( 28 ) comprising a male coupling member ( 38 ) having an external thread ( 42 ) and protruding rearwardly from a head base surface ( 40 ), the head base surface ( 40 ) extending transversely with respect to the head longitudinal axis (A), and defining a boundary between the cutting portion ( 26 ) and the mounting portion ( 28 ), wherein:
the external thread ( 42 ) comprises an external thread ridge ( 44 ) extending helically about an external thread axis (B) and comprising forward and rearward external flank surfaces ( 46 , 48 ) and an external top surface ( 50 ) extending therebetween;
the forward and rearward external flank surfaces ( 46 , 48 ) generally face in opposite axial directions (D F , D R ) and delimit a helical external thread groove ( 52 ) that comprises an external bottom surface ( 54 );
the external thread ( 42 ) of the male coupling member ( 38 ) is a back-tapered conical thread having at least one thread diameter (d 1 , d 2 ) which increases in the rearward direction (D R );
at least one of the external thread ridge ( 44 ) and the external thread groove ( 52 ) extends about a respective cone (K 1 , K 2 ) having a cone angle (γ); and
the cone angle (γ) is in the range of 0.4°≤γ≤1.0°.

2. The replaceable cutting head ( 22 ) according to claim 1 , wherein both the external thread ridge ( 44 ) and the external thread groove ( 52 ) extend about a respective cone (K 1 , K 2 ), an outer cone (K 2 ) and an inner cone (K 1 ), respectively.

3. The replaceable cutting head ( 22 ) according to claim 2 , wherein the cone angle (γ) is the same for the inner cone (K 1 ) and the outer cone (K 2 ).

4. The replaceable cutting head ( 22 ) according to claim 1 , wherein in a cross-sectional view taken in an axial plane containing the external thread axis (B):
the external top surface ( 50 ) forms a plurality of external thread crests ( 56 ) that are sloped with respect to the external thread axis (B) and co-linear with each other; and
the external bottom surface ( 54 ) forms a plurality of external thread roots ( 58 ) that are sloped with respect to the external thread axis (B) and co-linear with each other.

5. The replaceable cutting head ( 22 ) according to claim 1 , wherein in a cross-sectional view taken in an axial plane containing the head longitudinal axis (A), the external thread ( 42 ) defines an external thread form ( 60 ) that is trapezoidal.

6. The replaceable cutting head ( 22 ) according to claim 1 , wherein the external thread ( 42 ) has a constant external thread pitch (PE).

7. A rotary cutting tool ( 20 ) having a longitudinal axis (L) and extending in a forward (D F ) to rearward direction (D R ), comprising:
a tool holder ( 24 ) having a holder longitudinal axis (C) and comprising a female coupling member ( 68 ) having an internal thread ( 72 ) extending rearwardly from a holder forward surface ( 70 ), the holder forward surface ( 70 ) extending transversely with respect to the holder longitudinal axis (C); and
a replaceable cutting head ( 22 ) threadingly engaged to the tool holder ( 24 ), the replaceable cutting head ( 22 ) having a head longitudinal axis (A) extending in a forward (D F ) to rearward direction (D R ), and comprising
a forward portion forming a cutting portion ( 26 ); and
a rearward portion forming a mounting portion ( 28 ), the mounting portion ( 28 ) comprising a male coupling member ( 38 ) having an external thread ( 42 ) and protruding rearwardly from a head base surface ( 40 ), the head base surface ( 40 ) extending transversely with respect to the head longitudinal axis (A), and defining a boundary between the cutting portion ( 26 ) and the mounting portion ( 28 ), wherein:
the external thread ( 42 ) comprises an external thread ridge ( 44 ) extending helically about an external thread axis (B) and comprising forward and rearward external flank surfaces ( 46 , 48 ) and an external top surface ( 50 ) extending therebetween;
the forward and rearward external flank surfaces ( 46 , 48 ) generally face in opposite axial directions (D F , D R ) and delimit a helical external thread groove ( 52 ) that comprises an external bottom surface ( 54 ); and
the external thread ( 42 ) of the male coupling member ( 38 ) is a back-tapered conical thread having at least one thread diameter (d 1 , d 2 ) which increases in the rearward direction (D R );

wherein:
the rotary cutting tool ( 20 ) is adjustable between:
a released position in which the internal and external threads ( 42 , 72 ) are not threadingly engaged to one another, and
a locked position in which the male coupling member ( 38 ) is removably retained in the female coupling member ( 68 ) with the internal and external threads ( 42 , 72 ) threadingly engaged to one another; and

the frictional engagement between the external thread ( 42 ) and the internal thread ( 72 ) increases in a direction from a forwardmost turn of the external thread ( 42 ) towards the rearmost turn of the external thread ( 42 ).

8. The rotary cutting tool ( 20 ) according to claim 7 , wherein the internal thread ( 72 ) of the female coupling member ( 68 ) is a straight thread.

9. The rotary cutting tool ( 20 ) according to claim 7 , wherein:
the internal thread ( 72 ) comprises an internal thread ridge ( 74 ), extending helically about an internal thread axis (D), and comprising forward and rearward internal flank surfaces ( 76 , 78 ) and an internal top surface ( 80 ) extending therebetween;
the forward and rearward internal flank surfaces ( 76 , 78 ) generally face in opposite axial directions (D F , D R ) and delimit a helical internal thread groove ( 82 ) that comprises an internal bottom surface ( 84 ); and
the forward external flank surface ( 46 ) and the forward internal flank surface ( 76 ) face in the forward direction (D F );
the rearward external flank surface ( 48 ) and the rearward internal flank surface ( 78 ) face in the rearward direction (D R ); and
in the locked position, the rearward internal flank surface ( 78 ) abuts the forward external flank surface ( 46 ).

10. The rotary cutting tool ( 20 ) according to claim 9 , wherein in the locked position:
the forward internal flank surface ( 76 ) is spaced apart from the rearward external flank surface ( 48 ) by a rearward flank distance (D 1 );
the internal top surface ( 80 ) is spaced apart from the external bottom surface ( 54 ) by an upper distance (D 2 ); and
the internal bottom surface ( 84 ) is spaced apart from the external top surface ( 50 ) by a lower distance (D 3 ).

11. The rotary cutting tool ( 20 ) according to claim 7 , wherein the internal thread ( 72 ) has a constant internal thread pitch (PI) which is the same as a constant external thread pitch (PE) of the external thread ( 42 ).

12. The rotary cutting tool ( 20 ) according to claim 7 , wherein:
at least one of the external thread ridge ( 44 ) and the external thread groove ( 52 ) extends about a respective cone (K 1 , K 2 ) having a cone angle (γ); and
the cone angle (γ) is in the range of 0.02°≤γ≤1.0°.

13. The rotary cutting tool ( 20 ) according to claim 7 , wherein:
at least one of the external thread ridge ( 44 ) and the external thread groove ( 52 ) extends about a respective cone (K 1 , K 2 ) having a cone angle (γ); and
the cone angle (γ) is in the range of 0.4°≤γ≤1.0°.

14. A rotary cutting tool ( 20 )

Assignees

• Iscar Ltd

Inventors

• Khina Alexander
• Vainshtain Shmuel

Classifications

• B23C5/10 Primary

  Shank-type cutters, i.e. with an integral shaft · CPC title

• B23B2251/02

  Connections between shanks and removable cutting heads · CPC title

• B23C2240/32

  Connections using screw threads · CPC title

• Y10T279/16

  Longitudinal screw clamp · CPC title

• B23B31/1115 Primary

  using conical threads · CPC title