Note: Descriptions are shown in the official language in which they were submitted.
~ ~5552
The present invention relates to a ~etal cutting
tool, and more particularly, to a boring tool having a micro-
adjusting means for adjusting the cartridge holding the tool.
Previous inventions provide for ad; U5 ting the
cutting tool such as disclosed in -the following United States
Paten-ts: Eversole 3,801,213, Guli~on 3,765,7~8, Keller 4,105,360
and Shutz 2,266,339; and Russian Patent Samoilov 460,119.
However, the prior art fails to provide for adjusting the
cutting tool in small or micrometer increments.
According to the present invention there is provided
a tool cartridge attachable to a boring bar, there being
provided a ~ight portion, a pair of legs extending from the
bight portion in spaced apart, side-by-side relation with
each leg having a threaded bore means, one of the legs being
adapted for abutment against the boring bar when the cartridge
is attached thereto and the other of the legs carrying cutting
means thereon for cutting engagement with a workpiece when
the one leg is abutted against the boring bar and the other
leg is movable relative to the one leg. Screw means is
received in the t~readed bore means of the legs connecting
the legs such that rotation of the screw means moves the
other leg and cutting means carried thereon relative to the
one leg to adjust cutting diameter. Means is provided for
attaching the cartridge to the boring ~ar.
In a specific em~odiment of the invention, the
threaded bore means of the legs extend transversl~ across
the legs in axial alignment with one another, the threaded
bore means of the one leg and the other having different
pitch threads. A screw, which has corresponding different
pitch threads, is
~k
~ L65~35~
--2--
inserted through both legs of the cartridge. As the
screw is turned, ~he two halves or legs of the cartridge
tend to move away or close~ The movement of the
cutting tool mounted on one of the legs o the car~ridge
is radially adjusted depending upon the diEference
between the two threads per inch tapped in each leg of
the cartridge and ~orresponding threads on the differen-
tial screw.
BRIEF DESCRIPTIO~ OF THE DRAWINGS
Fig. 1 shows part o a boring bar with the
cartridge in place, and the radially adjustable cuttiny
tool secured thereto;
Fig. 2 shows a cross-section of the boring bar
and the cartridge, taken along line 2-2 of FigO 1;
Fig. 3 is a view taken along line 3-3 of Fig. 1;
Fig. 4 is a plan view of the bronze or steel
insert;
Fig. 5 is the end view of the ~ronze or steel
insert insert~
: Fig. 6 is a plan view of the differential
screw showing different threads per inch thereon.
3~ DESCRIPTION OF T~E INVENTION
With reference to ~ig. 1 and Fig. 2, the portion
of the boring bar 10 shows a recess 12 and a threaded
bore 13 which provides the cartridge 14 to be fastened
or secured thereto by a bol~ 16~ The ~artridge 14 has
a bight portion 18 and two legs 20 and 22 separated
by a recess 24. The reoess 24 terminates in a bore 26
~ ~ ~ 5 t~
--3--
to provide resilient movement of the legs 20 and 22 of
cartridge 14. Interconnecting the two legs ~0 and 22
is a recess 30. A bore 32 is reamed perpendicular to
recess 30 to accomodate bronze or stee:L inserts 36A and
36B (shown in Fig. 4 and Fig~ 5)0 In operation the
sub-assembly bronze or steel insert comprise semi-
circular halves 36A and 36B which are dropped in the
reamed bore 3~ of the cartridge 14. The bore 40A in
bronze or steel insert 36A is threaded to a pitch that
is different than the pitch in threaded bore 40B. For
example, the preferred embodiment shows that the
threaded bore 40A is ~6-40, the pitch being 1/40; and
the threaded bore 40B is ~10-32, the pitch being 1/32.
The pitch difference between 1/40 and 1/32 is approx-
imately .006 thousands of an.inch ~.031-.025j. The
pitch is defined as the distance, measured parallel to
its axis, between corresponding points on adjacent
threads in the same axial plane.
A differential screw, shown in Fig. 6, incorporates
two different tapped threads 46A and 46B in the same
direction. That is, both tapped threads are either
right hand or left hand threads. In the preferred
embodiment, one thread is tapped #6-40 and the other
thread is tapped #10-32~ The dif~erence between the--
two differen~ pitches provides the motion or radi.al
movement; for example, 40 threads per inch provides
motion of 1/40 or .025 thousands of an inch, and 32
threads per inch provides a motion of 1/32 or .031
thousands of an inch. The two pitch dimensions are
subtracted providing a difference of .006 thousands,
the difference throu~h which the two semi-halves bron~e
or steel inserts 36A and 36B start separating or coming
together as the differential screw is being rotated or
turned.
Thus, according to the preferred embodiment, the
differential screw is inserted through the bores of
5 ~ ~
4--
inserts 36A and 36B with the threads both right hand as
defined above, and as the differential screw 44 is
turned cloc~wise the bronze or steel inserts 36A and
36B are moved away rom each other. However, since leg
20 is relatively fixed in the recess of the boring ~ar
10, the leg 22 will move radially away-from the leg 20
of cartridge 14. The leg 22 comprises a recess 50 with
a clamp member S2 secured to the cartridge 14 by a
screw 53~ The.clamp member 52 is adapted to hold a
cutting tool 54 to the leg ~2 of cartridge 14.
Movement of differentla~ screw 44 in a clockwise
direction, with right hand tapped threads 40A and 40B
in inserts 36A and 36~ corresponding to r.ight hand
tapped threads 46A and 46B on shaft 44, causes the: leg
22 to move radially effecting the gap or recess 24 of
cartrid~e 14 to widen thus causin~ cutting tool 54 to
move radially outwardly. Moving the tool radia7ly
outwardly will cut a larger diameter of the workpiece.
To move the cutting tool 34 radiaIly inward,.the
: differential.screw 44 is turned counterclockwise,
causing the two semi-cir ular bronze or steel inserts
36A and 36B to move toward each other, effecting
movement of leg ~2 toward.leg 2n.
The bronze or steel p~ir of bushings or inserts
36A and 36B are made from a single round bar stock and
cut through the center to provide two symmetrical
halves or inserts. One insert is ~ored and threaded
with pit~h different from the threaded bore of the
other insert. The differential screw 44 has threads on
each end of the shaft ~orresponding to the threaded
bores of the two inserts 36A and 36B.
The invention described hereinabove provides more
micro adjustment per revolution. That is, one revolution
of a screw provides .02S inches, whereas one revolutlon
.
.
3 :~5~5~
of a differential screw, as d~scribed hereinabove,
provides . 006 inches. Furthermore, the cartridge is
cheaper to manu~acture and replacement is more economica:l.
