Note: Descriptions are shown in the official language in which they were submitted.
~230763
This invention relates to d combination bit and manufacturing
technique to produce, tn a single operation, end plugs for a paper spool.
Such end plugs each have a central aperture and peripheral faces, a major
portion of which are cylindrical, and a minor portion of which are frusto-
conical.
The art is replete with patents for circular hole cutters which
provide, simultaneously, two concentric apertures in a sheet material, where
the object is to provide a large diameter hole in the sheet material. Among
such patents are the following:
U.S. Patent 2,803,153 paten~ed August 20, 1957 by B.J. Goldbeck
U.S. Patent 2,926,555 patented March 1, ]960 by A.R. Joy
U.S. Patent 3,559,513 patented February 2, 1971 by E.D. Hougen
U.S. Patent 3,778,179 patented December 11, 1973 by D.F. Rivas
U.S. Patent 4,077,737 patented March 7, 1978 by M.K. Morse
Canadian Patent 7.73,879 patented December, 1967 by J.W. Goodyear
and Canadian Patent 843,069 patented June 2, 1970 by G. Val.
However, the art has not taught the provision of such a cutting
tool where the aim is the provision and retention of a plug removed from the
sheet material, rather than the provision of a hble in such sheet material,
where the removed mataerial is discarded.
Accordingly it is an object of a broad aspect of this invention to
provide a tool for the provision of a substantially cylindrical plug which
is provided with a central aperture and whose rounded faces are in the form
of a comp~ex shape having a cylindrical portion and a frusto-conical portion.
An object of another aspect of this invention is the provision of
; a novel manufacturing technique to produce such plugs, which may have diame-
ters from 1 inch to 24 inches, in a single step.
By one broad aspect of this invention, a combination bit is pro-
vided for producing, in a single operation, a substantially cylindrical plug
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having a central aperture, and complex rounded faces consisting of a cylin-
crical face and a coextensive frusto-conical face, the combination bit com-
prising: (a) an arbor; (b) a blade arrangement in the form of an inverted
cup secured to the arbor, the inverted cup having an upper plate and a de-
pending rim of the inverted cup being provided with a small plurality of
cutting teeth equally spaced therearound, each cutting tooth having a swept-
back forward edge, and a swept-back trailing edge, the cutting tooth having
a lower cutting face of sufficient depth to provide a cylindrical face of
the desired height on the plug formed, and an upper cutting face of suf-
ficient size disposed on the forward edge to provide a frusto-conical face
of the desired height on the plug being formed; and ~c) a central bit con-
centrically disposed within the inverted cup, and secured to the upper plate
of the inverted cup, to provide the central aperture in the plug being formed.
The bit so described may also include a changeable extractor plate
concentrically disposed on.the arbor above the inverted cup, the extractor
plate having means to secure the plate both to the arbor and to the inverted
cup. Preferably, the means to secure the plate to the inverted cup may in-
clude a plurality of circumferentially spaced vertical extending, rods. The
number of rods preferably is three, and the rods preferably are secured in
the extractor plate by means of screws engaged through the side face of the
extractor plate into a respective through aperture within which ~he rod is
disposed. Still more preferably, such means may include a stub shaft secured
to the arbor and extending between the extractor plate and the inverted cup,
the extractor plate being concentrically disposed on the stub shaft.
The arbor may be in the form of a Morse taper shaft, preferably
terminating in a substantially cylindrical stub shaft. In such case the cen-
tral bit is secured within a lower central aperture in the stub shaft.
Preferably, nine cutting teeth are provided on the inverted cup,
the leading edge of each of the teeth being swept-back by 15, the lower cut-
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Ling face being provided with a 30 cutting edge, and the upper cutting edge
being provided with an auxiliary cutting tooth canted at an angle of 2 .
The upper plate may preferably be provided with three finger ho]es.
By another aspect of this invention, a method is provided for pro-
ducing, in a single operation, a substantially cylindrical plug having a
central aperture, and complex rounded faces consisting of a cylindrical face
and a coextensive frusto-conical face, the method comprising: (A) providing
a combination bit in the form of an arbor; a blade arrangement in the form of
an inverted cup secured to the arbor, the inverted cup having an upper plate
and a depending rim, the depending rim of the inverted cup being provided
with a small plurality of cutting teeth equally spaced therearound, each
cutting too~h having a swept-back forward edge, and a swept-back trailing
edge, the cutting tooth having a lower cutting face of sufficient depth to
provide a cylindrical face of the desired height on the plug formed, and an
upper cutting face of sufficient size disposed on the forward edge to pro-
vide a frusto-conical face of the desired height on the plug being formed;
and a central bit concentrically disposed within the inverted cup, and secured
to the upper plate of the inverted,cup, to provide the central aperture in
plug being formed; (B) rotating the combination bit and applying it to a
sheet material; and (C) providing and recovering a plug provided with a cen-
tral bore and a complex curved face defined by a cylindrical piston and a
mer8ed frusto-conical portion.
The sheet material preferably is pressed wooden boaord, to provide
wooden plugs which may have a diameater of from 1" to 24".
In the accompanying drawings,
Figure 1 is a side elevational view of the combination bit of one
embodiment of this invention;
Figure 2 is a section along the line II-II of Figure l;
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Figure 3 is section along the line III-III of Figure l; and
Figure 4 is a longitudinal section through a cylindrical plug pro-
duced by the use of the combination bit of an embodiment of this inventic.n.
Referring firstly to Figures 1-3, as seen in Figure 1, the combina-
tion bit 10 of this embodiment of the present invention includes an arbor 11,
a movable extractor plate 12 and an inverted cup 13 secured to the arbor 11.
The arbor 11 has an upper shaft 14 in the form of a Morse taper shaft ter-
minating in a cylindrical stem 14a for insertion into a s~andard chuck of a
driil press (not shown). The arbor 11 extends to an integral lower stub
shaft 15 provided with a lower tapped bore 16 into which a central bit J7 is
secured in the usua] manner.
The changeable extractor plate ]2 includes a central bore 18 by
means of which it is mounted and centered on the stub shaft 15. The ex-
tractor plate 12 is secured to the inverted cup 13 by means of a plurality of
rods 19, i.e. three rods. ~Each rod 19 is secured within a respective axial
bore 20 by means of a set screw 21 mounted in tapped radial bore 22.
The inverted cup 13 is provided with a depending cylindrical rim
23 provided with a small plurality of cutting members 24, e.g. nine. Each
cutting member 24 includes a swept-back leading edge 25, preferably swept-
back at an angle of 15 , and a swept-back trailing edge 26. The lower face
27 of each cutting member 24 is provided with a cutting surface 28, preferably
s]oped at a cutting angle of 30 . The width of cutttng surface 28 is selected
to be equal to the height of the cylindrical face of the plug being fomred,
which will be described hereinafter with reference to Figure 4. The leading
edge 25 is provided with a cutting face 29 and an auxiliary tooth 30, whose
cutting face is canted at an angle of 2 . Cutting tooth 30 is of sufficient
widLh to provide the frusto-conical face of the plug being formed.
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1230~763
The inverted cupl3 is also provided with axial bores 31 which
accomodate rods 19 to secure the changeable extractor plate 12 to the inverted
cup 13. Each rod l9 is secured within a respective axial bore 31 by means of
a set screw 32 mounted on d tapped radial bore 33.
Also provided on the upper plate 34 of the inverted cup 13 are a
plurality of upstanding control rods 35 and depending from the lower surface
of the upper plate 34 is a lower support disc 36.
The view in Figure 2 is self explanatory, given the description of
Figure 1, with the only added explanation needed being that the apertures 20
are preferably disposed 120 apart.
As seen in Figure 3, ~he apertures 31 for the placement of rods 19
are disposed 120 apart to align with apertures 20 (see Figures 1 and 2).
The rods are likewise set 120 apart, but'offser from the apertures 31 both
radially and circumferentially. Also provided are three finger holes 36,
spaced 120 apart and offset from the other apertures 31 both circumferentially
. . .
and radially and from rods 35 circumferentially.
Figure 4 shows one embodiment of a plug formed in a singie step
from a sheet materi.;l, i.e. pressed board, using the combination bit of an
embodiment of thls invention. It consists of a wooden plug 100 provided with
a central bore lOl and a complex curved face defined by a cylindrical por-
tion 102 and a merged frusto-conical portion 103.
The combination bit of embodimenLs of thc inventioll may be pro-
vided by various ~iameters of the invertec cup and depending saw-tooth rim,
various diameters of the coaxial bit, and variou, small numbers and heights
of the composite cutting memDerS, to provide plugs of the desired size, e.g.
L rom I ~ to 24".
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