Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates yenerally to a
colnDination tool for a drill press and
particularly to a tool having cutter inserts
providing a planing operation and an abrasive
disc providing a f inishing operation.
The use of combination tools which provide
more than one machining function is well known
and there are several examples of such tools in
the prior art. For example, U.S. Patent No.
4~9,332 discloses a com~ined cutting and scouring
device. Tnis device teaches the use of two types
of outstandiny peripheral cutting edges, which
operate in the manner of a circular saw, combined
with the use of a sandpaper disc having a
finishing plane perpendicular to the cutting
edges of the cutters. The sandpaper is held in
place by a removable ring and is intended to
smooth the relatively rough cut surface resulting
from the circular saw action. ~owever, this
method of holding the sandpaper in place results
in an undesirable circumferential weariny edge.
In addition the perpendicular relationship
between the cutting plane and the a~rasive plane
is not beliaved to be conducive to the production
of a superior finished surface.
Also of interest are U.S. Patent No.
1,284,092 and U.S. Patent No. 1,35~,148. The
first of these references discloses a woodworkiny
29 machine providing an annular disc mounting
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non-radiall~ aliyned, anyled cutters for coarse
machininy and a circular disc mounting a
triangularly arranged set of rasp elements for
fine machininy, the face of the rasps beiny
adJ~stable relative to the cutter edyes. The
second reference, haviny the same inventive
entity as the first, is an improvement in that in
lieu of the rasps used for fine machining the use
of a second set of angled scrapers is
contemplated, the scrapers ~eing adjustable
relative to the cutters. These devices re~uire
complicated, and therefore expensive, adjustably
related parts and the possibility of
maladjustment is not condusive to the production
of a superior finished surface,
The Qresent tool overcomes these and other
problems in a manner not disclosed by the known
prior art.
This combination tool is used in conjunction
with a drill press and provides a means of finely
finishing wood and other materials, using cutter
inserts for coarse machininy and an abrasive disc
for fine machininy, without the need for
adjustment of the disc or inserts.
The plane of the aDrasive action is disposed
a ~redetermined distance outwardly of the plane
of the cuttiny action which assists in holding
the workpiece in place and permits the finishing
29 not only of hard wvods such as walnut, but soft
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woods such as balsa and other soft materials such
as st~rofoam plas~ic.
The inserts, ~hich provide coarse machining,
are held in place by a single fastener to
facilitate removal and replacement. In addition,
the inserts are dou~le-edged to provide
alternative machining edges and thereby prolong
the life of the inserts.
This combination planing and finishing tool
includes a shaft having an axis of rotation; a
body attached to the shaft and haviny a
substantially flat end face rotatable about the
axis of the shaft and havin~ a plurality of
circumferentially ~paced mounting means; a
plurality of replaceable cutter inserts, each
haviny at least one cutting edge, mounted to the
body with the cutting edge extending beyond the
end face to define a coaxial cuttin~ plane
disposed in perpendicular relation to the axis of
rotation, and a replacable abrasive disc attached
to the end face and providing a finishing plane
disposed parallel to and axially outwardly of the
insert cutting plane.
It is an aspect of this invention to provide
each of the cutter inserts with a side cuttiny
edge disposed in substantially parallel relation
to the a%is of rotation to facilitate the
machining action.
29 It is another aspect of this invention to
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provide that the body includes a peripheral edge
and to provide that the inserts are disposed
inwardly of said peripheral edge to reduce the
cutting force applied to the extremities of the
insert.
It is another aspect of this invention to
provide that each insert is generally rectangular
and of uniform thickness and includes opposed
front and rear faces, opposed upper and lower
faces, and opposed side faces. Yet another
aspect of this invention is to provide that the
rectangular insert has two horizontal cutting
edges and two vertical cutting edges so that the
inserts can be r~tated through one hundred and
eighty deyrees (180) to provide alternative
lower and side cutting edges. This rotational
capability increases the life of the insert in
the event that one edge becomes chipped.
It is still another aspect of this invention
to provide that each mounting means includes a
beariny face and a single fastener mountiny the
insert to the body with the rear face of the
insert engageable with the bearing face, the
cutting edge being radially disposed.
Still another aspect of the invention is to
provide that the Inounting means includes at least
one bearing face engageable by at least one edge
of an associated insert to substantially preclude
29 rotation of the insert about the fastener.
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Another aspect of this invention is to
provide that t~e body includes generally circular
inner and outer portions, said inner portion
haviny an underface and said outer portion being
diametricall~ smaller than said inner portion and
being notched to define a bearing face providing
at least part of the mounting means and
engageably receiving the rear face of an
associated insert, so that the insert is directed
10substantially parallel to the axis of the shaft.
Still another aspect of the invention is to
provide that the body inner portion includes
slotted portions adjacent each beariny Eace and
receiviny the front face of the inserts in
overlapping relation to resist cutting forces
applied to the insert horizontal and vertical
edges.
FIG. 1 is a view of the underside of the
combination tool;
20FIG. 2 is a cross section thereof taken on
line 2-2 of FIG. 1,
FIG. 3 is an enlarged perspective view of a
carbide insert, and
FIG. 4 is an enlaryed section taken on line
4-4 of FIG. 1,
Referriny now by reference numerals to the
drawings and first to FIGS. 1 and 2, it will be
understood that the combination tool generally
29indicated by numeral 10 includes a body 12,
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attached to a shaft 14 which is received by the
chuck 16 of the drill press, shown in phantom
outline. The body 12 carries both cutting means
and finishing means as will now be described.
The body 12, which in the embodiment shown
is of ~ie-cast zinc, includes a circular inner
portion 18 and a generally circular outer portion
20 of reduced diameter. The body inner portion
1~ includes a hub 22 to which the shaft 14 is
attached as by pin 24. The inner portion 18 is
recessed at 26 to reduce weight and includes a
peripheral edge 28 and a flat underface generally
indicated by numeral 30.
The body outer portion 20 includes a reduced
diameter end portion 32 which is recessed to
provide a circular flat face 34. The recessed
face 34 receives the adhesive face of a pres~ure
sensitive attached abrasive disc 36, which is
centrally mounted for rotation about the axis of
the shaft 14. In the embodiment shown a 50 grit
abrasive disc is used which provides a superior
finishing means for the material being worked.
An emery cloth abrasive disc having a thickness
of about 1,5mm used with a rim of 0.6mm provides
a suitable projection of the face of the disc
byond the rim 33 defining the recessed face 34.
The radius of the recessed face 34 is about 1.5 -
2.0mm yreater than the radius of the abrasive
29 disc 36 which facilitates centering of the disc.
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The body outer portion 20 also carries a
planing or cuttiny means in the form of a
plurality of cutter inserts 40, three in number
in the embodiment shown, and mounted to the body
at circumferentially spaced intervals of one
hundred and twenty degrees (120) as will be
described.
The cutter inserts, which are best shown in
FIG. 3, are generally rectangular, of
substantially uniform thickness, and include
opposed front and rear faces 42 and 44, opposed
upper and lower inclined ~aces 46 and opposed
inclined side aces 48. In the embodiment shown,
the rearward angle of inclination A of the upper
and lower faces 46 and the side faces 48 is
between ten and thirty degrees (10-30) and
an angle of twenty-five degrees (25) will
provide excellent results. ~he upper and lower
faces 46 and the side faces 48 cooperate with the
front f ace 42 to define two sets of carbide
cutting edges 46' and 48' respectively disposed
in perpendicular relation to each other. The
inserts 40 are provided with a centrally disposed
fastener receiving aperture 50 for mounting to
the body 12 as will now be described with respect
to one insert, said other inserts being identical,
In order to mount the inserts 40 securely to
the body 12 the outer body portion 20 is notched
29 and slotted to provide a rear abutment bearing
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face 52 parallel to the axis of rotation which
receives the insert rear face 44 in beariny
engayement. The bearing face 52 is provided with
a threaded opening 54 to receive a fastener such
as a socket screw 56. The slot 58 provides an
overlapping front abutment bearing face 60 which
receives the insert front face 42 in bearing
engagement. As best shown in FIG. 4 the slot 58
also provides a side bearing face 62 which
cooperates with the underface 30 of the body
inner portion 18 to provide a stop means
precluding rotation of the insert 40 about the
fastener 56. To this end, it will be understood
that any tendency for the insert 40 to rotate
will be resisted by engagement between the body
underside 30 and the insert upper edge 46' and by
engagement between the slot side 62 and the
insert side edge 48' as indicated in FIG. 4. It
will be understood that there is a minimum amount
of play between engayeable edges 46' and 48' and
faces 30 and 62, which in the embodiment shown is
of the order of O.lmm. When mounted the
operating insert cutting edge is disposed
substantially radially relative to the axis of
the shaft 14.
The circular finishing plane deined by the
abrasive disc outer face 36', and the annular
cuttiny plane defined by the insert lower cutting
29 edges 46' are parallel to each other and
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perpendicular to the axis of rotation of the tool
10. In the embodiment shown the lower cuttiny
edge 4~' extends beyond the recessed face 34
about l.Omm which provides a suitable projection
beyond the rim 33 defining the recessed face 34.
Im~ortantly, and as shown in FIG. 2, these
parallel planes are spaced apart a distance d
which, in the embodiment shown, is O.5mm and
which will work well within the range of 0.5mm to
l.Omm depending on the thickness of the abrasive
disc 36 and the disposition of the lower cutting
edge 46'. Because of this arrangement, by ~hich
the abrasive plane is disposed axially outwardly
of the cutting plane, the work is held in place
and only a small thickness of material is left to
be finished as the workpiece passes under the
tool creating a finished path having a width
equal to the diameter of the tool as defined by
the vertical edge 48', which is perpendicular to
the horizontal edge 46', and provides assistance
in the cutting process. In the embodiment shown
the diameter of the disc 36 is about 5.3cm and
the length of the insert lower cutting edge 46'
is about 1.5cm providing a ratio in excess of
three to one (3:1).
As shown in FIG. 2, insert 40 is disposed
radially outwardly of the abrasive disc but
radially inwardly of the body portion circular
29 edge 28. Because of this there is no extended
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radial peojection of the inserts beyond the
limits of the body 12. As shown, the inserts 40
project only a short distance beyond the abutment
provided by bearing face 52 and is thereby
securely seated in position. Further, the
provision of the overlapping slot front face 60
tends to resist forces applied to the horizontal
and vertical cutting edges 46' and 48' as they
perform their cutting operation.
The operational speed of the preferred
embodiment is three thousand five hundred
revolutions per minute t3500 r.p.m.) and it will
be understood that at this speed, and with a
cutting diameter of ~.5cm this represents a
maximum linear speed of the cutting edges in
excess of fifteen hundred cm per second (1.5
c.p.s.). At these speeds it has been found that
the tools run efficiently without undue heating.
The symmetrical nature of the inserts 40
provides that when the operating horizontal and
vertical edges 46' and 48' respectively become
dulled the inserts can be removed, rotated
through one hundred and eiyht degrees ~180)
and replaced, this operation being considerably
facilitated by the need to remove only the single
fastener 56. The abrasive disc 36 is removed by
peeling from the recessed face 34, and it will be
understood that the disc is substantially the
~ 29 same diametric size as the recess such that the
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recess sidewalls ten~ to maintain the disc in
place.
Although the tool is intended primarily for
planing and finishing wood, and particularly hard
woods such as walnut, it can also be used on much
softer materials such as balsa woods and even
styrofoam because of the high quality of the
cutting and finishing action.
The improved capability of this combination
tool to plane and finish wood results from its
combined action of cutting and fine sanding which
enables the tool to provide veneers as thin as
1.5mm. This capability is due, at least in part,
to the fact that sanding occurs almost
immediately after the rough cut is made.
Further, the provision of a circular finishing
plane which extends beyond the parallel cutting
plane assists in keeping the work flat and in
place even when relatively large knots are
encountered. This arrangement has also proved to
be economical with respect to the long life
experienced by the abrasive disc of up to sixty
hours.
In view of the above it will be seen that
; various aspects and features of the invention are
achieved and other advantageous results
attained. While a perferred embodiment of the
invention has been shown and described, it will
29 be clear to those skilled in the art that changes
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and mod if ications may be made therein without
departing from the invention in its broader
aspect .
.
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