FIELD OF THE INVENTION
The present invention generally relates to a method of Turning/Boring on
horizontal machining centers. More particularly, the present invention relates to a
Boring Bar having a fine tool adjustment means adaptable to horizontal
machining centers.
BACKGROUND OF THE INVENTION
At present, turning/boring process on horizontal machining centers is carried out
by using boring bars with cutting tool clamped in its slot by a screw as shown in
figure 3(a) and 3(b). For machining for example, configurating an exact diameter
on components, the tool in undamped by unscrewing the screw and then set
manually by a trial and error method. After a cut is taken on the component, the
diameter of the component is measured and the tool is reset again. To achieve a
fine tolerance it takes a substantially higher time to set the tool. Thus the
processing time gets unusually extended leading to high cost.
OBJECTS OF THE INVENTION
An object of the present invention is to propose a boring bar having a fine tool
adjustment means which eliminates the disadvantage of the prior art.
Another object of the present invention \s to propose a boring bar having a fine
tool adjustment means, which achieves a tolerance in steps of 0.01 mm.
Yet another object of the present invention is to propose a boring bar having a
fine tool adjustment means which ensures quick and accurate setting of the tool
leading to reduction in tool setting time.
A further object of the present invention is to propose a boring bar having a fine
tool adjustment means which eliminates the step of manual setting of the tool
for fine tolerance machining.
SUMMARY OF THE INVENTION
Accordingly, there is provided a boring bar adaptable to horizontal machining
centers having a fine adjustment means comprising: a main bar having a shank
corresponding to machine spindle mounting device, a tool slot for a tool and
atleast two holes for clamping the tool via a square head bolt; a lever fixable on
the main bar via a first hole by means of a hexagonal head bolt, a micrometer
head screw fixable to the main bar via a second hole through second hole of
lever with a spherical washer on the lever under the screw, and atleast two
springs fixed on the holes of the lever and the main bar.
The micrometer head rotation provides for fine movement of the tool in steps of
0.01 mm and the spring aids in back movement of the tool.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1(a) - shows a boring bar having a fine adjustment means according to
the present invention.
Figure 1(b) - shows the boring bar having a fine adjustment means with a
micrometer head screw according to an embodiment of the
present invention.
Figure 2 - shows the layout of a main bar, a lever, a spring, a hexagonal head
screw, a spherical washer, a plurality of screws, and a hexagonal
head bolt and washer.
Figure 3(a) and (b) - show the diagram of prior art with tool clamped in boring
bar with screws.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF
THE INVENTION
Figure 1(a) shows a boring bar which comprises a main bar (1) fixed on the
machine spindle by its shank. A lever (2) fixed on the main bar (1) by means of a
hexagonal head bolt (7) and a washer (8). A micrometer head screw (4) is
screwabiy disposed, in the main bar (1) with a spherical washer (5) on the lever
(2). Atteast two springs (3) is fixed in the holes of the lever (2) and the main bar
(1). Atleast two square head bolts (6) are provided for clamping the tool.
Figure 1(b) shows a boring bar with a micrometer head screw (4).
As shown in figure 2, the main bar (1) is fixed/mounted on the machine by the
shank (suiting to machine tool).
The lever (2) is placed on the main bar (1) through a guiding key of the main bar
(1).
A threaded hole (HI) is provided for clamping the lever (2) through a first hole
(hi) with the main bar (1) via a hexagonal head bolt (7) and a washer (8).
Before clamping the lever (2), atleast two springs (3) are inserted in a first pair
of holes (H3) of the main bar (1) and it goes in a second pair of holes (h3) of the
lever (2) while clamping.
The Spherical washer (5) is placed on the lever (2) and the micrometer head
screw (4) is inserted in a second hole (h2) of the lever (2) and screwed in a third
hole (H2) of the main bar (1).
During machining, the tool is clamped in a tool slot'S' by the atleast two square
- head bolts (6) through a fourth hole (H4) and a fifth hole (h4) of the main bar
(1), and the lever (2) respectively.
While finishing the process of boring/turning, the bolt (6) in the fourth hole (H4)
of the main bar (1) is unscrewed and a finer adjustment of the tool is done by
the micrometer head screw (4).
Accuracy of the tool movement is ensured by the atleast two springs (3) and the
guiding keys.
The bolt (6) remaining in the fourth hole (H4) of the main bar (1) after final
adjustment is tightened.
Each rotation of the micrometer screw (4) causes a movement of 0.01 mm to the
tool. The micrometer head divisions with actual movement of the tool is
calibrated when a complete rotation is given to the micrometer screw (4). /
WE CLAIM
1. A tool holder adaptable to horizontal machining centre, comprising:
a main bar (1) having a shank adaptable to the horizontal
machining centre and a tool slot (S) for clamping of the tool
including a fourth hole (H4) for clamping;
a lever (2) fixable on the main bar (1) by a first hole (hi) of the
lever (2) on a threaded hole (HI) of the main bar (1) by means
of a hexagonal head bolt (7);
atleast two square head bolt (6) fixable to the main bar (1) and
the lever (2) for clamping the tool; and
atleast two springs (3) fitted in between a first pair of hole (H3)
of the main bar (1) and a second pair of hole (h3) of the lever for
accurate setting of the tool,
characterized in that a micrometer head screw (4) is fixed on the main
bar (1) with the lever (2) which on imparting a predetermined rotation
causes a transfer of the rotating force to a vertical load on the lever
(2), and in that the lever (2) allows the tool to move forward
accurately in the slot (5) to a predetermined distance guided by the
keys and two springs (3).
2. The tool holder as claimed in claim 1, wherein the bolt (6) in the hole
(H4) during movement of the tool is kept loose, and wherein the bolt
(6) is finally tightened after the tool being set.
3. The tool holder as claimed in claim 1, wherein the lever (2), the atleast
two springs (3), the micrometer head screw (4), a spherical washer (5)
the atleast two square head bolts (6), the hexagonal head bolt (7) and
a washer (8) together constitute a fixing, moving and setting means.
4. The tool holder as claimed in claim 1, wherein the micrometer head
screw (4) has corresponding number of divisions marked with a thread
pitch combination so that one division rotation of the screw (4) results
in 0.01 mm movement of the tool.
5. The tool holder as claimed in any of the preceding claims wherein the
lever (2) is made of hardened spring steel.
6. The tool holder as claimed in any of the preceding claims wherein the
lever (2) has a line marking in a flat centre portion for reference to
rotation of micrometer head screw (4).
7. The tool holder as claimed in any of the preceding claims wherein the
main bar (1) is made of case hardened alloy steel.
8. A tool holder adaptable to horizontal machining centre, substantially as
herein described and illustrated in the figures of the accompanying
drawings.

A tool holder adaptable to horizontal machining centre, comprising: a main bar
(1) having a shank adaptable to the horizontal machining centre and a tool slot
(S) for clamping of the tool including a fourth hole (H4) for clamping; a lever (2)
fixable on the main bar (1) by a first hole (h1) of the lever (2) on a threaded
hole (H1) of the main bar (1) by means of a hexagonal head bolt (7); atleast two
square head bolt (6) fixable to the main bar (1) and the lever (2) for clamping
the tool; and atleast two springs (3) Fitted in between a first pair of hole (H3) of
the main bar (1) and a second pair of hole (h3) of the lever for accurate setting
of the tool. A micrometer head screw (4) is fixed on the main bar (1) with the
lever (2) which on imparting a predetermined rotation causes a transfer of the
rotating force to a vertical load on the lever (2), and in that the lever (2) allows
the tool to move forward accurately in the slot (5) to a predetermined distance
guided by the keys and two springs (3).