Rotary cutting tool including cutting head having coupling pin with guiding and fastening recesses
A cutting head has driven surfaces and includes a head coupling pin that protrudes rearwardly from a head rear surface. The head coupling pin includes guiding and fastening recesses recessed in the pin peripheral surface, the guiding recess opening out to the pin rear surface. A tool holder assembly has a tool holder and an elastic fastening assembly. The tool holder has driving members and a holder coupling hole recessed in a holder base surface. The elastic fastening assembly is disposed in a holder through bore that extends from the holder base surface to a holder peripheral surface. When a cutting tool which includes the cutting head and tool holder is in a fastened position, the head coupling pin is removably retained within the holder coupling hole upon elastic engagement with the elastic fastening assembly.
1. A rotary cutting tool ( 20 ) comprising:
a cutting head ( 22 ) having a head central axis (A) defining a forward to rearward direction (D F , D R ) and about which the cutting head ( 22 ) is rotatable in a rotational direction (R), the cutting head ( 22 ) comprising a forward end forming a cutting portion ( 28 ) and a rearward end forming a head coupling portion ( 30 );
the cutting portion ( 28 ) comprising:
a head rear surface ( 34 ), defining a boundary between the cutting portion ( 28 ) and the head coupling portion ( 30 );
a head rear abutment surface ( 38 ), located on the head rear surface ( 34 );
two cutting arms ( 42 ) extending radially with respect to the head central axis (A), each comprising a driven surface ( 50 ); and
the head coupling portion ( 30 ) comprising a head coupling pin ( 60 ), protruding rearwardly from the head rear surface ( 34 ) along the head central axis (A), the head coupling pin ( 60 ) comprising:
a pin rear surface ( 62 ) spaced apart from the head rear surface ( 34 ) and a pin peripheral surface ( 64 ) extending therebetween;
a guiding recess ( 66 ), recessed in the pin peripheral surface ( 64 ), opening out to the pin rear surface ( 62 ), and comprising a guiding surface ( 68 ) extending in a forward axial direction from the pin rear surface ( 62 ) towards the cutting portion ( 28 ); and
a fastening recess ( 70 ), recessed in the pin peripheral surface ( 64 ), and comprising a lower inclined surface ( 73 c ) which is radially outwardly sloped relative to the head central axis (A), in the rearward direction (D R ) of the cutting head ( 22 ); wherein
at least a portion of the lower inclined surface ( 73 c ) axially overlaps an overlapping region ( 74 ) of the guiding surface ( 68 ), said portion comprising a fastening surface ( 72 a ) that is angularly closer to said overlapping region ( 74 ) in the direction opposite the rotational direction (R) than in the rotational direction (R); and
a tool holder ( 24 ), having a holder longitudinal axis (D), extending in the forward to rearward direction (D F , D R ) and about which the tool holder ( 24 ) is rotatable in the rotational direction (R), the tool holder ( 24 ) comprising:
a holder peripheral surface ( 78 ) extending circumferentially along the holder longitudinal axis (D) and forming a boundary of a holder base surface ( 80 ) at a forward end of the tool holder ( 24 );
two circumferentially spaced apart driving members ( 84 ) extending forwardly from the holder base surface ( 80 );
a holder coupling hole ( 96 ) recessed in the holder base surface ( 80 ) and extending along the holder longitudinal axis (D) in the rearward direction (D R ); and
a holder through bore ( 102 ) extending along a holder through bore axis (B) from the holder coupling hole ( 96 ) to the holder peripheral surface ( 78 ); and
an elastic fastening assembly ( 26 , 126 ) releasably engaged to the tool holder ( 24 ) at the holder through bore ( 102 ), and having a protruding portion ( 122 ) protruding into the holder coupling hole ( 96 ); wherein
the rotary cutting tool ( 20 ) is adjustable between a guided position and a fastened position, wherein:
in the guided position:
the head coupling pin ( 60 ) is located in the holder coupling hole ( 96 ); and
the protruding portion ( 122 ) is located in the guiding recess ( 66 ); and
in the fastened position:
the cutting head ( 22 ) is releasably attached to the tool holder ( 24 ) by the elastic fastening assembly ( 26 , 126 );
the head coupling pin ( 60 ) is located in the holder coupling hole ( 96 );
each cutting arm ( 42 ) is in contact with a respective driving member ( 84 ); and
the elastic fastening assembly ( 26 , 126 ) elastically engages the fastening surface ( 72 a ).
2. The rotary cutting tool ( 20 ), according to claim 1 , wherein the fastening surface ( 72 a ) is radially inwardly sloped relative to the head central axis (A), in the rotational direction (R) of the cutting head ( 22 ).
3. The rotary cutting tool ( 20 ), according to claim 1 , wherein
a fastening axial half-plane (P F ) extending from the head central axis (A) intersects the fastening surface ( 72 a ); and
the fastening axial half-plane (P F ) intersect one of the driven surfaces ( 50 ).
4. The rotary cutting tool ( 20 ), according to claim 1 , wherein the fastening surface ( 72 a ) is located in a portion of the lower inclined surface ( 73 c ) that is closest to the overlapping region ( 74 ) of the guiding surface ( 68 ) in a direction opposite the rotational direction (R).
5. The rotary cutting tool ( 20 ), according to claim 1 , wherein the guiding surface ( 68 ) is planar and parallel to the head central axis (A).
6. The rotary cutting tool ( 20 ), according to claim 1 , wherein the overlapping region ( 74 ) of the guiding surface ( 68 ) intersects the fastening surface ( 72 a ).
7. The rotary cutting tool ( 20 ), according to claim 1 , wherein the fastening surface ( 72 a ) is planar.
8. The rotary cutting tool ( 20 ), according to claim 1 , wherein the head coupling pin ( 60 ) comprises exactly one guiding recess ( 66 ) and exactly one fastening recess ( 70 ).
9. The rotary cutting tool ( 20 ), according to claim 1 , wherein
the tool holder ( 24 ) comprises a holder base abutment surface ( 82 ), located on the holder base surface ( 80 ); and in the fastened position of the rotary cutting tool ( 20 ):
the head rear abutment surface ( 38 ) abuts the holder base abutment surface ( 82 ).
10. The rotary cutting tool ( 20 ), according to claim 1 , wherein in the fastened position of the rotary cutting tool ( 20 ):
in a cross-sectional view taken in a first tool plane (P 1 ) perpendicular to the head central axis (A) and through the fastening surface ( 72 a ), the holder through bore (B) forms an acute first angle (γ) with the fastening surface ( 72 a ), the acute first angle (γ) being measured in a direction opposite the rotational direction (R); and
in a cross-sectional view taken in a second tool plane (P 2 ) containing the head central axis (A) and the holder through bore axis (B), the holder through bore (B) forms an acute external second angle (δ) with the fastening surface ( 72 a ).
11. The rotary cutting tool ( 20 ), according to claim 1 , wherein, the cutting head ( 22 ) is angularly displaced, relative to the tool holder ( 24 ), by no more than 90° upon adjustment between the guided position and the fastened position of the rotary cutting tool ( 20 ).
12. The rotary cutting tool ( 20 ), according to claim 1 , wherein
the rotary cutting tool ( 20 ) is further adjustable between the fastened position and a locked position, and in the locked position:
the cutting head ( 22 ) is releasably attached to the tool holder ( 24 ) by the elastic fastening assembly ( 126 );
the head coupling pin ( 60 ) is located in the holder coupling hole ( 96 );
each cutting arm ( 42 ) is in contact with a respective driving member ( 84 ); and
the elastic fastening assembly ( 126 ) clampingly engages the fastening surface ( 72 a ).
13. The rotary cutting tool ( 20 ), according to claim 12 , wherein
the elastic fastening assembly ( 126 ) extends along an elastic fastening assembly axis (C) that is co-axial with the holder through bore axis (B);
the elastic fastening assembly ( 126 ) comprises a fixation member ( 206 ), a rigid member ( 108 ) and an elastic biasing member ( 110 ) located axially therebetween along the elastic fastening assembly axis (C);
the protruding portion ( 122 ) is located on the rigid member ( 108 );
the fixation member ( 206 ) is releasably engaged at the holder through bore ( 102 );
the elastic biasing member ( 110 ) is a biasing spring ( 112 );
the fixation member ( 206 ) further comprises a locking portion ( 124 ) extending towards the rigid member ( 108 ) through the biasing spring ( 112 );
the fixation member ( 206 ) is displaceable along the through bore axis (B), and in the locked position of the rotary cutting tool ( 20 ):
the locking portion ( 124 ) abuts the rigid member ( 108 ).
14. The rotary cutting tool ( 20 ), according to claim 1 , wherein
the head coupling pin ( 60 ) comprises exactly one guiding recess ( 66 ) and exactly one fastening recess ( 70 ); and
the tool holder ( 24 ) comprises exactly one holder through bore ( 102 ) and exactly one elastic fastening assembly ( 26 , 126 ) releasably engaged to the tool holder ( 24 ).
15. The rotary cutting tool ( 20 ), according to claim 1 , wherein
the elastic fastening assembly ( 26 , 126 ) extends along an elastic fastening assembly axis (C) that is co-axial with the holder through bore axis (B);
the elastic fastening assembly ( 26 , 126 ) comprises a fixation member ( 106 , 206 ), a rigid member ( 108 ) and an elastic biasing member ( 110 ) located axially therebetween along the elastic fastening assembly axis (C);
the protruding portion ( 122 ) is located on the rigid member ( 108 ); and
the fixation member ( 106 , 206 ) is releasably engaged at the holder through bore ( 102 ).
16. The rotary cutting tool ( 20 ), according to claim 15 , wherein
the rigid member ( 108 ) comprises an end surface ( 114 ) that is perpendicular to the elastic fastening assembly axis (C) and a side surface ( 116 ) that extends circumferentially along the elastic fastening assembly axis (C) and circumferentially bounds the end surface ( 114 ); and
the end surface ( 114 ) and the side surface ( 116 ) intersect to form a beveled surface ( 117 ); and in the fastened position;
a portion of the beveled surface ( 117 ) abuts the fastening surface ( 72 a ).
17. The rotary cutting tool ( 20 ), according to claim 1 , wherein the holder through bore axis (B) lies in a holder plane (P) perpendicular to the holder longitudinal axis (D).
18. The rotary cutting tool ( 20 ), according to claim 1 , wherein the holder through bore axis (B) intersects the holder longitudinal axis (D).
19. The rotary cutting tool ( 20 ), according to claim 1 , wherein
each cutting arm ( 42 ) comprises arm rotationally leading and trailing surfaces ( 44 , 46 ) and an arm peripheral surface ( 48 ) extending peripherally therebetween;
each arm rotationally trailing surface ( 46 ) comprises an arm latch ( 52 ) that protrudes therefrom and extends in a direction from the head central axis (A) to the arm peripheral surface ( 48 );
each driving member ( 84 ) comprises driving member rotationally leading and trailing surfaces ( 86 , 88 ) and a driving member peripheral surface ( 90 ) extending peripherally therebetween;
each driving member rotationally leading surface ( 86 ) comprises a driving member undercut ( 94 ) that is recessed therefrom and extends in a direction from the holder longitudinal axis (D) to the driving member peripheral surface ( 90 ); and
each arm latch ( 52 ) is located in a respective driving member undercut ( 94 ).
20. The rotary cutting tool ( 20 ), according to claim 1 , wherein, in the fastened position, the elastic fastening assembly ( 26 , 126 ) elastically engages the fastening surface ( 72 a ) at a contact region that is rotationally behind the holder through bore axis (B).
21. The rotary cutting tool ( 20 ), according to claim 1 , wherein, in the head coupling pin ( 60 ) is non-fluted.
22. The rotary cutting tool ( 20 ), according to claim 1 , wherein:
the elastic fastening assembly ( 26 , 126 ) is adjustable between a fastened position in which the elastic fastening assembly ( 26 , 126 ) has a first length (L 1 ), and a locked position in which the elastic fastening assembly ( 26 , 126 ) has a second length (L 2 ), the first length (L 1 ) being longer than the second length (L 2 ); and
the protruding portion ( 122 ) continues to protrude into the holder coupling hole ( 96 ), as the elastic fastening assembly ( 26 , 126 ) is adjusted between the fastened position and the locked position.
23. The rotary cutting tool ( 20 ), according to claim 22 , wherein:
the elastic fastening assembly ( 26 , 126 ) extends along an elastic fastening assembly axis (C) that is co-axial with the holder through bore axis (B); and
the elastic fastening assembly ( 26 , 126 ) comprises a fixation member ( 106 , 206 ), a rigid member ( 108 , 208 ) and an elastic biasing member ( 110 , 210 ) located axially therebetween along the elastic fastening assembly axis (C).
24. The rotary cutting tool ( 20 ), according to claim 23 , wherein:
the fixation member ( 206 ) is axially spaced apart from the rigid member ( 208 ), along the elastic fastening assembly axis (C), by the elastic biasing member ( 210 ), when the elastic fastening assembly is in the fastened position and has the first length; and
the fixation member ( 206 ) abuts the rigid member ( 208 ), when the elastic fastening assembly in the locked position and has the second length.