Cutters – for shaping – Including holder having seat for inserted tool – With separate means to fasten tool to holder
Reexamination Certificate
2000-02-28
2002-01-01
Tsai, Henry (Department: 3722)
Cutters, for shaping
Including holder having seat for inserted tool
With separate means to fasten tool to holder
C407S117000, C407S107000
Reexamination Certificate
active
06334742
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a tool for chip removing machining, preferably for parting/grooving, comprising an insert mechanically clampable to a holder. The insert is arranged to be clamped in a slot in the holder by means of a spring-load that arises between the walls of the slot when the insert is pushed into the slot and produces a deflection of one of the slot walls. The invention further relates to an insert to be clamped in the holder.
Such a tool is disclosed in U.S. Pat. No. 4,801,224, the disclosure of which is incorporated by reference herein. That tool
10
, depicted herein in
FIGS. 1 and 2
, comprises a holder
11
and an insert
12
. The holder
11
has a rear end, not shown, adapted to be secured to a machine. The free front end of the holder is provided with a slot
13
defined by first and second opposing walls
14
,
15
each having a generally V-shaped cross-section. The wall
14
comprises mutually angled planar wall sections
14
a
,
14
b
, and the wall
15
comprises mutually angled planar wall sections
15
a
,
15
b
. The upper portion of the holder which carries the wall
15
forms an integral cantilever-type clamping arm
16
arranged to clamp the insert between the walls of the slot by means of resilient force when the insert is pushed rearwardly into the slot. The angled wall sections of each wall
14
,
15
converge toward the insert to form the V-shape. The wall sections of each wall meet in a rounded-off apex portion and enclose an internal obtuse angle. The front surface of the clamping arm
16
is comprised of a planar abutment surface
17
which determines the final position of the insert
12
in the slot.
The insert
12
is formed of sintered hard metal, such as cemented carbide, especially, tungsten carbide, and comprises a pair of longitudinally extending V-shaped first and second surfaces
21
,
22
. The first surface
21
extends parallel to the feed direction A of the tool. The second surface
22
comprises mutually inclined front and rear portions
23
,
24
, which together form an included obtuse angle. The rear portion
24
terminates rearwardly at a location separated from the first surface
21
by a rear face
20
. The rear portion
24
converges toward the surface
21
and forms a wedge angle therewith. The surface
21
is configured to slide along the lower wall
14
of the slot, and the portions
23
,
24
are configured to slide along the upper wall
15
of the slot. The sides of each surface
21
,
22
meet in a central rounded-off portion (see
FIG. 2
) and form an external obtuse angle which is larger than the internal angle formed between corresponding portions at the holder. Contact occurs between the surface
21
and the wall
14
and between the front portion
23
and the wall
15
at each side of the midline M of the tool (
FIG. 2
) during the final phase of insertion.
The broader, front part of the insert body is provided with a cutting edge
25
arranged to part or to face a work piece, not shown. Furthermore, the insert is provided with parallel planar side faces
26
,
27
and transversely directed front and rear end faces
28
,
29
. The front portion
23
of the surface
22
is generally parallel to the surface
21
in that it could be exactly parallel or slightly inclined such that it diverges from the surface
21
in a rearward direction.
During insertion of the insert
12
into the slot
16
, the rear portion
24
of the surface
22
engages a front end
19
of the clamping arm
16
and elastically deflects the clamping arm away from the opposing portion of the holder. Eventually, the front end
19
engages the front portion
23
of the surface
22
and comes into contact with an abutment surface
30
of the insert. The insert
12
is now frictionally held between the walls
14
and
15
of the slot.
Although this frictional securement is usually adequate, it may occur on occasion that the insert becomes inadvertently dislodged from the holder.
It is, therefore, an object of the invention to increase the frictional forces that secure the insert in the holder.
SUMMARY OF THE INVENTION
The objects are achieved by a parting/grooving tool which comprises a holder and an insert removably secured in the holder. The insert includes front and rear ends. The front end contains a cutting edge, and the rear end includes a rear face. Upper and lower surfaces of the insert are of generally V-shaped cross-section and extend along a front-to-rear direction. The V-shape is bisected by a longitudinal midplane of the insert. The holder includes a forwardly opening slot formed by upper and lower front-to-rear extending walls of V-shaped cross-section. Each wall is defined by mutually angled wall sections. The walls face one another and engage the upper and lower surfaces, respectively, of the insert. The walls are elastically flexed apart to frictionally grip the upper and lower surfaces, respectively. At least one of the upper and lower surfaces is provided with recess patterns situated on respective sides of the longitudinal midplane. Each of the recess patterns is configured to define non-recessed portions of the at least one surface, the non-recessed portions being spaced apart along the front-to-rear direction. The wall sections of the holder which engages the at least one surface are planar and frictionally engage the non-recessed portions and extend across the recess patterns.
Preferably, both of the upper and lower surfaces possess the recess pattern and the non-recessed portions.
The invention also pertains to the parting/grooving insert per se.
REFERENCES:
patent: 1131538 (1915-03-01), Mason
patent: 2453959 (1948-11-01), Anthony et al.
patent: 4801224 (1989-01-01), Pettersson et al.
patent: 5743608 (1998-04-01), Von Hass et al.
patent: 5803675 (1998-09-01), Von Haas
patent: 5836723 (1998-11-01), Von Hass et al.
patent: 5888029 (1999-03-01), Boianjiu
patent: 5931613 (1999-08-01), Larsson
patent: 6086291 (2000-07-01), Hansson et al.
patent: 6168356 (2001-01-01), Sjoo et al.
patent: 0 420 512 (1991-04-01), None
patent: 0 802 006 (1997-10-01), None
Sandvik Inc.
Tsai Henry
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