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Патент USA US2136083

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' Nov. 8, 1938.
. p, H_ NAST
- 2,136,083
TOOL FORGING METHOD
Filed Jan. 30, 1954
2 Sheets-Sheet 1
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-
Nov. 8, 1938.
TOOL FORGING METHOD
Filed Jan. 50, 1954
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2,136,083
P. H. NAST
v
2 Sheets-Sheet 2
1329.5
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Patented Nov. 8, 1938
2,136,083
UNITED STATES PATENT OFFICE
2,136,083
TOOL FORGING METHOD
Paul H. Nast, Claremont, N. H., assignor to Sul
livan -Machinery Company, a corporation of
Massachusetts
Application January 30, 1934, Serial No. 708,996
5 Claims. (Cl. 76-108)
This invention relates to tool forging methods,
and more particularly to improved methods of’
forming the cutting bits of rock drill steels.
In forming the cutting bits of rock drill steels,
5 it is customary to swage the sides of the bit wings
prior to the upsetting operation. In swaging, the
forward ends of the wings of the bit have usually
been formed with plane surfaces at a.70° angle,
and thus a clearance is provided, when the bit is
placed in a 90° angle dolly, so that the metal may
?ow on upsetting to a sharp edge. During upset
ting, the wing sides are formed with plane surfaces
at an‘angle of 90°, and the clearance above men
tioned is provided so that the cutting edge is upset
15 more readily when bringing the wing shape back
from the 70° angle to the 90° angle of the wings.
However, it has been found that even with this
process upsetting does not uniformly produce a
sharp edge; and I have found that if the wing
sides are formed with concave surfaces instead
of the plane surfaces at a 70° angle prior to the
upsetting operation, the cutting edge is formed
more easily and surely during upsetting, since
there is more clearance and less metal to ?ow to
obtain the desired shape of cutting edge with
piane wing surfaces at a 90° angle. Concave wing
surfaces are of particular importance in re
sharpening steels wherein the cutting edges are
rounded down by wear, since the 7()-0 plane sur
faces on the wings do not suf?ciently draw out
the metal so that proper upsetting is possible.
An object of this invention is to provide im
proved tool forging methods for forming the cut
ting bits of rock drill steels. Another object is
to provide improved forging methods whereby the
In these drawings,—
Fig. 1 is a side elevational View of the illustra
tive form of improved forging dies, with a rock
drill steel in forging position therein.
Fig. 2 is a plan view of Fig. 1, with the upper
die removed.
Fig. 3 is a diagrammatic View showing a bit
wing in an intermediate stage of sharpening in
accordance with a former method.
Fig. 4 is a diagrammatic view showing a bit in
an intermediate stage of being formed by the im
proved method.
Fig. 5 is a detail view showing the upsetting
dolly and steel-clamping blocks of the forging
machine with which the improved forging dies
are used.
Fig. 6 is a perspective view of the improved
forging dies.
In this illustrative embodiment of the invention
there is shown a pair of die blocks I and 2 of
which the lower die block 2 is adapted to be sup
ported in a stationary anvil block of a drill steel
forging machine of a standard design, while the
upper die block i may be carried by a reciprocat
ing hammer member and caused to be moved to
ward and from the stationary die block 2 with a
rapid hammering action, or may be held by suit
able means in proper position relative to the lower
block‘ and percussively actuated; it being a well
known fact that rock drill bits are usually sharp
ened by a hammering process combined with a
dollying process for the purpose of forming the
wings 3 of the bit of a standard rock drill steel
4. These improved swaging dies-are provided
with swaging surfaces 5 and 6, respectively, and
cutting edges of a drill steel bit are formed in an
grooves '! and B to receive the more or less ?nished
improved manner. A further object of this in
vention is to provide improved methods for shap
ing the wings of a cross bit prior to the upsetting
40 operations so that the’ latter operation may be
accomplished more readily and in an improved
manner. Yet another object is to provide im
wings, these grooves being so formed as to receive
and shape the outer longitudinal surfaces of the
proved forging methods whereby the cutting edges
of such bits are formed by concaving the sides of
45 the bit wings prior to the .upsetting operation,
thereby improving the cutting edges obtained.
Still another object is to provide an improved
method of making drill bits. These and other
objects and advantages of the invention will,
11 O however, hereinafter more fully appear.
In the accompanying drawings there is shown
for purposes of illustration one form which the
invention, as a structure, may assume in practice,
and one method of practicing it from its aspect as
55 an art.
wings which are not being swaged laterally.
These wing-forming grooves open out laterally
through the sides of ‘the bit blocks at 9 to permitv
the escape of scale or other foreign substances
from between the die surfaces. During the swag
ing operation heretofore common, the wings of
the bit have been formed with plane surfaces at
a 70° angle, as indicated at H] in Fig. 3, and there
after during the dollying or upsetting process the
70° angle surfaces of the wings have been upset
by the dolly to the 90° plane surfaces, as indi
cated at II in Fig. 3, to provide a cutting edge at
I 2 ; but, as above mentioned, it has heretofore
been found that, particularly when the drill bits
are being resharpened, the surfaces on the die
blocks did not properly form the wing surfaces
from the 70° angle shown at In in Fig. 3 to the de 55
2,136,083
sired cutting shape of 90° indicated at l I in Fig. 3.
In order to overcome this disadvantageous
feature, the improved die blocks shown herein
are provided with convex surfaces I3 and I4,
so that during the swaging operation the wings
of the bit are formed with concave surfaces, as
indicated at I5 in Fig. 4, that is the surfaces or
While there is in this application speci?cally
described one method of practicing the inven
tion, it will be understood that this is done for
purposes of illustration and that the invention
may be modi?ed and otherwise practiced without
departing from its spirit or the scope of the
wings are formed in the manner indicated in full
appended claims.
What I claim is new and desire to secure by
lines in Fig. 4 in place of the usual 70° angle sur
Letters Patent is:
10 faces If! indicated in full lines in Fig.7 3, the
surfaces of the bit wings, after the swaging opera
tion, assuming the form shown in Fig. 2. The
dihedral angles in whose sides lie the intersec
tions and the rearward extremities of the in
15 clined sides of the wings may be said to be of
less angular inclusion than the dihedral angle of
the ?nished bit. Evidently the die surfaces l3
and M will cooperate to form at the projected
(i. e. planned) cutting end of a bit a pair of con
20 cave surfaces intersecting in a line in advance of
the intended ultimate edge of the tool and having
the elements thereof parallel to such a line.
After the swaging operation has been com
pleted, the drill steel is placed between clamping
blocks it and IT, as shown in Fig. 5, of the forg
ing machine, and rigidly clamped in position
therebetween. The dolly l8 of the sharpening
~machine, whose sides form a dihedral angle of
greater inclusion than the dihedral angle ?rst
so, above mentioned, is then percussively actuated so
as to hammer the concaved surfaces of the bit
wings. With this form of concave surfaces on
the bit wings, there is ample clearance between
the 90° angle forming surfaces IS on the dolly
35: face so that the metal of the bit readily flows into
a shape to conform with the 90° angle surfaces
of the dolly, the surfaces of the wings being
formed from the shape indicated in full lines in
Fig. 4 to the proper 90° angle cutting shape with
sharp edge as indicated at l l in construction lines
in Fig. 4. It will thus be seen that the convex
surfaces of the swaging dies will form a concave
impression on the bit Wings which allows more
working clearance during the upsetting operation
so that the cutting edge is upset more readily
when bringing the wings back to" the proper 90°
shape.
As a result of this invention, it will be noted
that improved methods are provided for forming
the cutting bit of a rock drill steel prior to the
upsetting operation so that upsetting is more
readily accomplished and the cutting edges are
formed in an improved manner.
It will further
be noted that by forming the forging dies with
convex surfaces so that the wings of the cutting
bit are formed with concave surfaces, the metal
in the wings of the bit flows into proper shape in
an improved manner during the upsetting opera
tion and with less work and wear on the part of
60 the dollying mechanism. Theseand other uses
and advantages of the improved forging method
‘will be clearly apparent to those skilled in the art.
l. The method of forming cutting edges of a 10
cross bit comprising initially swaging the wing
surfaces of the bit into a concave form and there
after upsetting the wing surfaces by a dollying
process to increase the angle adjacent the cutting
edge.
15
'
2. The method of forming cutting edges on a
cross bit comprising initially swaging the wings
with the forward and rear extremities of their
tapered portions at the edge and in the sides of a
dihedral angle of 'less than the desired angle of
the ?nished bit, and with the surfaces of the
tapered portions concave, and upsetting said
tapered portions with a dolly grooved to form a
dihedral angle of the desired ?nished shape.
3. The method of forming the cutting end of
a tool to provide a cutting edge at the'intersec
tion of surfaces diverging rearwardly from said
cutting edge, comprising initially forming at the
end of said tool a pair of concave surfaces inter
secting at an angle less than the ultimate desired 39
angle between the diverging surfaces of the'?n
ished end, and upsetting said end with die means
having material-working intersecting surfaces di
verging from their intersection at a greater angle
than the angle at the end of the partially formed
tool.
'
4. The method of forming the cutting end of
a tool to provide a cutting edge at the inter
section of surfaces diverging rearwardly from said
cutting edge, comprising initially forming at the 40
end of said tool a pair of concave surfaces inter
secting in a line in advance of the ultimate
desired cutting edge of the ?nished end, and up
setting said end with die means having material
working intersecting surfaces diverging from
their intersection at a greater angle than the
angle at the end of the partially formed'tool.
5. The method of forming the cutting end of
a tool to provide a cutting edge at the intersec
tion of surfaces diverging rearwardly from said 50
cutting edge, comprising initially forming at the
end of said tool a pair of concave surfaces inter
secting at an angle less than the ultimate desired
angle between the diverging surfaces of the fin
ished end and in a line in advance of the ulti 55
mate desired cutting edge of the ?nished end,
and upsetting said end with die means having ma
terial-working intersecting surfaces diverging
from their intersection at a greater angle than
the angle at the end of the partially formed 60
tool.
PAUL H. NAST.
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