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Патент USA US2404048

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July 16, 1946-
Filed Aug. 5', 1944 '
2,404,048 ‘
Patented July 16, ‘1946
Franklin G. Gepfert, Shaker Heights, Ohio
Application August 5, 1944, Serial No. 548,150
2 Claims.
This invention relates to drills, and particu
larly to drills used for penetrating hardened met
als. This particular invention is an improvement
of the drill patented by Lester G. Black, on Octo
ber 28, 1941, under Patent No. 2,260,288.
The primary object of this invention is to pro
and are equidistant from and parallel with each
other. The body portion of the drill just below
the shank portion In is slightly conical and in all
other respects follows the standard Morse taper
dimensions used for some of the prior art drills.
The end portion of the drill speci?cally shown
in the Figures 2, 3, 4 and 5 of the drawing has
vide a drill of the type mentioned which more
rapidly removes the chips or shavings from the
three acute radially and longitudinally extending
hole being drilled. It also enables the drill to be
ridges I5 which extend from the longitudinal axis
used for a longer period of time without resharp 10 or center ll! of the drill to the center of each of
the three ?llets l2. These ridges are formed by
These and other objects of the invention will
grinding three perfectly flat facets I4 thereon at
an angle of forty degrees from the longitudinal
become apparent from the following speci?cation“
and claims, together with the accompanying
axis of the drill and form thereat three laterally
drawing, wherein like parts are referred to and 15 extending ridges [9. The acute radially extend
ing ridges l5 of the end portion are the only
indicated by like reference characters and
parts of this drill that make frictional contact
Figure 1 is a view of the improved drill as it is
with the work being perforated, and are at an
angle of about sixty degrees from the longitudinal
mounted in a collet chuck;
Figure 2 is an enlarged elevational view of a 20 axis of the drill. This drill, unlike the drill
portion of the body of the drill and the end
shown in the Patent No. 2,260,288 which has per
thereof as viewed from one angle;
fectly straight ?at flutes and straight non-inclin
Figure 3 is a view similar to that of Figure 2 but
ing parallel ?llets, does not burnish or scrape the
viewed from another angle;
inside surface of the hole due to the upward taper
Figure 4 is a view similar to that of Figures 2 25 of the instant body.
and 3 but viewed from still another angle or di
The chip clearance grooves I6 of the instant
drill are somewhat/larger than the grooves of the
rection; and
earlier drill shown in the lPatent No. 2,260,288 and
Figure 5 is a bottom end view of the drill.
they make possible an easier passage of the chips
Referring to the drawing, there is shown in
the Figure l a drill having a shank portion l0 30 upward along the flutes I I. These grooves 16 are
concave and consume the large central portions of
which ?ts into a regular collet chuck 8 or other
the facets l6 and thereby smoothly connect with
holder. The Figure 1 also shows a cross section
the adjacent flutes l I.
of the work 9.
It will now be clear that there is provided by
The drill member consists of three integral
parts which will be described separately. First, 35 this invention a drill for penetrating hardened
metals and which accomplishes the objects set
there is the round shank portion I0 that is more
forth. While the invention is illustrated and de
or less standard and which in itself possesses no
scribed in a certain preferred form, it is obvious
novel features, as far as this invention is con
that there may be other forms or adaptations of
cerned. Next, there is the body portion of the
drill which is below the shank portion ID. The 40 the invention. For example, the drill body may
body portion has three spiraliform ?utes I l and
be made with four or more ?utes and ?llets in
stead of with the three as shown. The drill body
three helical ?llets I2 therebetween. The ?utes
may also be made of untapered stock, if desired.
II are ground out of the solid metal forming the
The drill end for some purposes may be made
body portion and‘are preferably substantially flat
or straight across. However, they are very 45 straight or concave instead of being pointed as
slightly concave in cross section, as is shown in
shown. These modi?cations are also considered
the Figure 5 due to the convexity of the grinding
to be included in this invention, as no limitations
upon it are intended other than those imposed
wheel. The ?llets [2 are not sharp but are
slightly convex. Peripheral lines on the convex
thereon by the scope of the appended claims.
surfaces of the ?llets 12 are parallel to the pe 50
I claim:
rlpheral surface of the shank portion and have
slightly smaller arcs, but are concentric there
with, as is clearly shown in the Figure 5. The
helixes or spirals formed by the ?llets are uni
1. A drill of the type described, comprising in
combination, a round shank portion receivable
by a holder, a body portion substantially trian
gular in cross section integral with the shank
form throughout the entire length of the body 56 portion and having spiraliiorm ?utes thereon
forming helical ?llets therebetween, the said
?utes having substantially ?at surfaces and the
said ?llets having peripheral surfaces concentric
with the said shank portion, and a pyramidal end
portion integral with the body portion and hav
portion and having three or more spiraliform
?utes thereon forming three or more helical ?l
lets therebetween, the said ?utes having substan
tially ?at surfaces, and an end portion integral
with the body portion and having three or more
ing ?at facets thereon forming straight radially
facets thereon forming three or more radially
and longitudinally extending ridges therebe
tween, each of the said facets abutting a ?ute
and longitudinally extending ridges therebe
tween, each of the said facets being at an angle
of about forty degrees from the axis of the drill
and forming thereat a lateral ridge, each of the
said radially extending ridges abutting a ?llet 10 and abutting a ?ute and forming a lateral ridge
and all of the same forming a sharp point at the
thereat, each of the said radially extending
ridges abutting a ?llet and all of the same form
axis of the drill, the said body and end portions
having a concave groove at each lateral ridge,
ing a sharp point at the axis of thedrill, the said
and each of the said grooves consuming a sub
body and end portions having a concave groove
stantially large portion of the facet thereat.
15 at each lateral ridge, and each of the said grooves
2. A drill of the type described, comprising in
consuming a substantially large portion of the
combination, a shank portion receivable by a
facet thereat.
holder, a body portion integral with the shank
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