Cutting tool

A cutting tool for parting and grooving operations comprises a shaft and a clamp body releasably secured to the front end of the shaft. The clamp body carries a cutting insert clamped between a pair of clamp arms. The clamp body includes first and second blade portions oriented at a right angle to one another. The first blade portion is adapted to be secured to one outer surface of the shaft, whereas the second blade portion is adapted to be secured to a second outer surface of the shaft.

BACKGROUND OF THE INVENTION 
The present invention relates to a tool for chip forming machining of metal 
workpieces specifically for grooving and parting operations. The tool 
comprises a clamp with an insert and a releasable holder shaft attached 
thereto. The clamp comprises a securing portion mating with the shaft and 
an extension portion. 
A large number of tools for grooving and parting are previously known where 
the tool comprises a shaft and an insert-provided clamp attached thereto, 
which clamp is secured to the holder shaft. Sletten U.S. Pat. No. 
3,844,008 discloses a tool which comprises an insert-carrying clamp body 
in the shape of a blade attached against one side surface of a holder 
shaft by means of a clamping screw. The screw is received in a hole that 
extends transversely through the clamp body and is threadedly engaged in a 
threaded hole in the holder shaft. In order to achieve a good location and 
good stability, the blade-like clamp is additionally provided with an 
extension at one of its side surfaces which is received in a complementary 
shaped lateral recess in the holder shaft. Further, the holder shaft also 
has a corresponding lateral recess on its opposite side surface. This 
enables the same holder shaft to be equipped with a clamp for either right 
or left hand turning. 
However, it will be necessary to use separate clamps having the extensions 
provided on the appropriate side thereof. 
It turns out, however, that such a tool does not always give the desirable 
maximum stability during machining of materials with difficult or average 
machinability properties. Further, it is desirable to be able to use a 
holder system designed so it enables machining the workpiece in two 
directions oriented perpendicular to one another without having to use 
different tools for each operation. 
SUMMARY OF PREFERRED EMBODIMENTS OF THE INVENTION 
The present invention relates to a new type of tool which eliminates the 
above-mentioned and other problems and which also provides a high degree 
of versatility. At the same time, it will be possible to facilitate and 
produce such tools at lower costs due to its simple construction. 
A significant feature of this new tool is that it comprises a first blade 
portion and a second blade portion oriented perpendicularly from the first 
blade portion. According to one embodiment, one preferred mounting screw 
is threadably engaged in the holder shaft for the purpose of securing the 
first blade portion and another screw is used for similarly securing the 
second blade portion to the shaft in a direction perpendicularly to the 
direction of the first screw.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
In FIGS. 1 and 1A, a clamp body 10 comprises a forwardly extending first 
blade portion 11, so-called because it is in the shape of a thin plate. 
The first blade portion 11 carries a cutting insert 12 with a cutting edge 
12a for parting and grooving operations. The insert 12 is in this 
embodiment received in a recess 13 at the forward end of the blade portion 
11. The clamp force exerted on the insert 12 is provided by an upper clamp 
arm 14a which is made integral with the blade portion 11 by a slot 15 
formed therein. The clamp arm is activated by tightening a clamp screw 16 
Which extends downwards through the slot 15 and into a lower clamp arm 14b 
of the blade portion 11. A rear end 17 of the blade portion 11 extends 
rearwardly and integrally from and in the same plane as the clamp arms 
14a, 14b. The rear end 17 is provided with a laterally extending bore 18 
which extends entirely through the blade portion 11 for the receipt of a 
complementary mounting screw (similar to screw 19 shown in FIG. 2) 
intended to be threadably engaged in a hole 27 of a holder shaft 20 (see 
FIG. 4). 
The clamp body 10 is provided with a second blade shaped portion 21 
functioning as a mounting portion while oriented perpendicularly from the 
first blade shaped clamp portion 11. The second blade portion 21 is of 
integral one-piece construction with the first blade portion 1. A slit S 
is formed between upper sections of the first and second blade portions 
11, 21 to permit the upper clamp arm 14a to be deflected downwardly toward 
the second clamp arm 14b. That is, the second blade portion 21 is 
connected with the first blade portion 11 only at a location below the 
slot 15. In order to firmly secure the second blade portion 21 to the 
holder shaft 20, the second blade portion is provided with a hole that 
extends entirely therethrough for the receipt of a mounting screw 23 
(similar to the screw 23 of FIG. 2) which is to be threadably engaged into 
a corresponding bore 25 of the front surface 24 of the holder shaft. 
The holder shaft 20 is preferably designed in such manner that the center 
line Cl.sub.1 of the bore 25 (which extends through an outer transverse 
surface 24 in the axial direction of the shaft 20) is oriented in the same 
horizontal plane P (see FIG. 1A) as the center line Cl.sub.2 of the bore 
27 that extends through outer side surfaces 28, 29 of the shaft and 
perpendicularly to the bore 25. Also, the cutting edge 12a is preferably 
oriented in that same horizontal plane with the center lines Cl.sub.1 and 
Cl.sub.2. The side surfaces 28, 29 are oriented parallel to a longitudinal 
axis L of the shaft and the transverse surface 24 is perpendicular to that 
axis L. 
As shown in FIGS. 4-5, the transversely extending bore 27 of the holder 
shaft 20 extends entirely through a front head portion 20a of the shaft 
and terminates in two opposed parallel side surfaces 28 and 29. This 
enables the same holder shaft to be used for both right and left hand 
turning. The side surfaces 28 and 29 are coplanar with the remaining 
rearwardly extending sides of the holder shaft 20. Elongated recesses 30 
and 31 are provided in the side surfaces 28, 29, respectively, and in the 
axial direction of the shaft. Those recesses are intended to receive 
positioning and stabilizing wedge elements W (see FIG. IA). Each of the 
recesses 30, 31 is open longitudinally forwardly and laterally outwardly 
and includes perpendicularly oriented surfaces 31a, 31b. A further such 
recess 32 is also provided in the front surface of the shaft 20 (see FIG. 
4). The body 10 would be provided with complementary recesses such that 
the wedge element is received partly in the shaft 20 and partly in the 
body 10. 
A great deal of versatility is achieved with such a tool. Due to its square 
or rectangular shape in cross section the manufacture can be made simpler 
and cheaper. The recess 27 for the screw 19 can be straight and made to 
extend entirely through the shaft 20. This enables the same holder and 
clamp body 10 to be used for machining a workpiece in a normal position as 
shown in FIG. 1 or to use the same tool in an upside down position as 
depicted in FIG. 1B. In FIG. 1B, the clamp body 10 has been detached from 
the shaft 20, rotated by 180.degree. about the axis of hole 25, and then 
reattached to the shaft. This is accomplished while keeping the cutting 
edge 12a at the same elevation, i.e., the cutting edge remains in the 
plane P which includes the centers of the bores 25 and 27. 
In the FIG. 1B arrangement, the first blade portion 11 (which previously 
engaged the outer side surface 29 of the shaft 20) engages the outer side 
surface 28 (which lies parallel to surface 29), while the second blade 
portion 21 still engages the transverse outer surface 24. 
When making light cuts, only the mounting screws 19 and 23 are needed to 
secure the body 10 to the shaft 20. For heavier cutting and large slotting 
depths, such mounting should additionally also include the usage of a 
positioning element or wedge W located in the elongated recess 30 or 31 or 
32 (see FIG. 1A). 
FIG. 2 depicts an alternative arrangement which is similar to that of FIG. 
1, but wherein the rear end 17' of the first blade portion 11' is stepped 
inwardly at 17a relative to the front section of the first blade portion 
11' Such an arrangement provides for better accessibility in certain 
operations. 
Another alternative embodiment of the invention show in FIG. 3 involves a 
boring bar 20" for internal turning in a workpiece (not shown). In this 
embodiment, a mounting screw 19 is securing the first blade portion 11" 
against a forward transverse outer end surface 24a of the generally 
cylindrical boring bar shaft 20, whereas the second blade portion 21" is 
releasably secured against one outer side surface 28a of the boring bar 
20". The lower edge of the first blade portion 11" has been circularly 
shaped in order to facilitate the machining of a circular hole of the 
workpiece 14a, 14b. 
The second blade portion 21" is secured to shaft 20" by a screw (not shown) 
which extends into a through-hole 25" in the outer side surfaces 28a, 29a 
of the shaft. That hole 25" extends completely through the shaft 20" and 
thus enables the body 10" to be reversed by mounting the second blade 
portion 21" against the side surface 29a of the shaft. Alternatively, the 
body 10" can be adjusted by 90.degree. by attaching the first blade 
portion 11" to one of the side surfaces 28, 29, and attaching the second 
blade portion 21" to the transverse surface 24a. 
The insert 12 can be clamped by means of a clamping screw (not shown) 
similar to the clamping screw 16 of FIG. 1, or by the inherent elasticity 
of the clamping arms 14a", 14b". Note that the clamping arms 14a", 14b" 
are relatively shorter than those of FIGS. 1 and 2 to facilitate a usage 
of the body 10" in the position depicted in FIG. 3, i.e., for use in 
boring through a workpiece. 
In an alternative tool embodiment shown in FIGS. 6-7, the front portion of 
the holder shaft 20'" is provided with a slot 33 that extends in the same 
plane as an upper surface 20a of the shaft. The clamp body 10 is, similar 
to the embodiments of FIGS. 1-5, provided with first and second 
blade-shaped portion 11'" and 21'". The first blade portion 11'" includes 
a slot 34a, which is terminated by a round recess 35 in the rear portion 
of the first blade portion. The diameter of the recess 35 is larger than 
the width of the slot 34a. The second blade portion 21'" is also provided 
with a corresponding slot 34b. The slot 34b is contiguous with the slot 
34a and thus divides the second blade portion 21'" into upper and lower 
parts 21a, 21b which project perpendicularly from the first blade portion 
11'". The forward portion of the holder shaft 20'" is, similar to FIG. 2, 
in the shape of a rectangle. Transverse bores 36 and 37 are provided in 
that forward portion one on each side of the slot 33. Further, two 
longitudinal threaded bores 38 and 39 are provided in the front surface 
24b of the shaft 20'" while being perpendicular and coplanar in relation 
to the bores 36 and 37, respectively. The clamp body 10'" is provided with 
correspondingly provided bores 40, 41 and 42, 43, respectively. In order 
to further improve the mounting stability of the body 10'", a further 
threaded bore 44 is provided in the lower portion of the shaft to be 
aligned with a corresponding bore 45 in the forward blade shaped clamp 
portion 17. 
The front portion of the shaft 20'" is provided with a vertical threaded 
hole 50 which extends perpendicular to the common planes of holes 36-38; 
37-39; and 44-45. That hole 50 is adapted to receive a screw 52. By 
tightening the screw 52, the upper and lower parts 21a'"21b'" (and thus 
also the clamping arms 14a'", 14b'") are moved together to clamp an insert 
(not shown). 
Although the present invention has been described in connection with 
preferred embodiments thereof, it will be appreciated by those skilled in 
the art that additions, modifications, substitutions and deletions not 
specifically described may be made without departing from the spirit and 
scope of the invention as defined in the appended claims.