Note: Descriptions are shown in the official language in which they were submitted.
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A HOLE CUTTER
FIELD OF THE INVENTION
The present invention relates to a tool for
cutting holes, for example, in walls, floors and ceilings
and other building applications and in surfaces such as
surfcraft decks, boats etc. The invention finds particular
application with the cutting of holes for electrical,
plumbing, building and engineering applications, and in the
cutting of plug holes for detachable surfboard fins (such
as shown in Australian Patent Number 665804). The
invention will be primarily described in these
applications, but i.t should be appreciated that the
invention can be used to cut holes, grooves, recesses etc
in a broad variety of applications and in varying surfaces,
substrates and materials.
BACKGROUND TO THE INVENTION
Hole saws. are known in building and engineering
applications. For Example, some hole saws are adapted for
fitting into a power drill to be rotated thereby and are
used for cutting holes in a wide variety of surfaces and
substrates. Hole saws have a tendency to become clogged,
however, as debris tends to be retained within the saw
interior.
So-called ~~speed bore" drills are also employed
to form holes, being a drill bit with an enlarged cutting
head at the drilling end thereof. However, the speed bore
blades wear rapidly and very firm control of the power
drill must be mains=wined if an even hole is to be formed.
Detachable fins for surfcraft have been known for
some time. Detachable fins have the advantage that they can
be removed for transport of the surfcraft, and when a fin
is broken it can be readily replaced. The fitting of
recently developed detachable fins (such as shown in
Australian Patent loo. 665804), and also the fitting of
legrope plugs, has presented the surfcraft manufacturer
with new challenges, and current techniques have to some
extent slowed down the overall surfcraft manufacturing
process.
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Received 8 March 2000
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It would be advantageous if a hole cutter could
be provided which may assist in the easier or faster
formation of holes in a variety of substrates and surfaces.
SUMMARY OF THE INVENTION
The present invention provides a hole cutter for
cutting a hole in a surface, comprising:
- a cutting head having a cavity therein and a
cutting surface at one end for cutting the hole, with a
passage for a drill extending from the cavity to the
cutting surface; and
- a drill adapted for being rotatably driven for
relative axial movement in the cavity between a first
position in which the drill extends through the pas~~age and
a cutting end of the drill projects beyond the cutting
surface, and a second position in which the drill has been
at least partially retracted into the head;
such that. in use, when the drill is rotatably
driven whilst in the first position it can be advanced into
the surface to drill. a pilot hole therein until the cutting
head contacts the s~_zrface, wherein the drill can then be
moved relatively axially in the head to the second
position, and thereafter further rotation of the drill
causes the cutting head to rotate to enable cutting of the
hole.
The dril.:L thus provides an initial ease of
penetration into a t~urface (a drill providing a relatively
high point force at= the surface). It also enables the
cutting head to be st:ably brought into engagement with the
surface to be cut. furthermore, the drill car: be
preferably en~irely retracted into the cutting head so that
thereafter the cutting head only continues with the hole
cutting. Thi~~ retraction can thus prevent over-penetration
by the drill into t::he surface.
Such a tc:of can also readily form a hole for a
plug, which when f=i.tted in a surfcraft (eg. a surfboard)
can then fasteningly receive therein a respective lug
projecting from a ~>ase of a fin (such as a fin shown in
Australian Patent Pro. 665804). The hole can also easily
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receive a so-called legrope plug.
Thus, the preparation of the hole can be
achieved by the one tool in a simple operation (eg.
typically with the tool fitted in the end of a standard
portable power dril.l).
Usually the cutting head is of a unitary
construction, with an abrasive surface being formed or
defined at a cutting end thereof. However, the cutt=ing
head can be defined by a body having a detachable cutting
end thereat, such that ends of different sizes and shapes
can be attached to the body for cutting different sized
holes (ie with the remainder of the hole cutter being
unchanged). The ends can be screw fitted to the body (in a
male-female threaded coupling arrangement), or a bayonet
fitting can be provided for enabling ease of attachment and
detachment of different ends to the body.
Preferably said adaptation of the drill includes
a drill holder into which the drill is incorporated in use,
and wherein the dr:i.l1 holder is guided in the cavity during
said axial movemen~. The use of a drill holder facilitates
a more controlled and robust operation of the tool.
Typically the flange moves freely and unencumberedly in the
cavity between the first and second positions in use.
Preferably a C-shaped slot is provided in a wall
of the head, and a pin extends from the drill holder and
into the slot to move therein and facilitate said guidance.
This arrangement further enhances the controlled and robust
operation of the tool.
Preferably the pin is located in a bottom end of
the slot in the first position of the drill, and can be
located in a top end of the slot in the second position of
the drill, the pin and slot being adapted for interacting
in use such that the rotation of the drill holder in both
the first and second positions causes a corresponding
rotation of the head. Thus, in the first position the
drill can perform a pilot hole drilling function, and in
the second posit3.on the drill can be essentially benign,
leaving cutting t:o the cutting head.
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Preferably the drill holder has a bore extending
part way therethraugh, and into which the drill is fixedly
received. In this regard, the pin can extend through the
drill holder to engage against the drill when in the bore
to fasten the dri:Ll in the drill holder. The non-cutting
end of the drill c-.an alternatively or additionally be
adhesively affixed i.n the bore (eg. with Loctite TM
adhesive).
Preferably a spring loaded ball is positioned in
a slot formed in the holder on an opposite side to t:he pin,
in use the ball being urged by the spring against an
internal wall of the head to further facilitate said
guidance. Again, this makes for smoother movement of the
drill holder in the cavity.
Preferably an opening is formed in an end of the
head opposing said one end and extending from the cavity,
with the holder including a shank which extends out from
the opening for engagement by a rotating drive (eg. to be
locked in the chuck of a portable power drill) that can in
turn drivingly rotate the drill in use.
Preferably a ring is externally positioned around
the head that can be located up and down a side wal7_
thereof in use, the ring having a pin that extends
internally therefrom and into a longitudinal slot formed at
the side wall, such that the pin can be selectively
fastened at various positions in the longitudinal slot,
such that in use when the ring ultimately engages with the
surface, the cutting head is prevented from being further
advanced into the surface in use. Thus, the ring can be
located to enable t:he cutting head to cut only to a certain
depth or to prevent the head from cutting right through a
surface in use.
BRIEF DESCRIPTION OF THE DRAWINGS
Notwithstanding any other forms which may fall
within the scope of the present invention, preferred forms
of the invention will now be described, by way of example
only, with reference to the accompanying drawings in which:
Figures 1 and 2 show, respectively, side and underside plan
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elevations of a preferred drill holder in accordance with
the present invention;
Figures 3 and 4 show, respectively, side and underside plan
elevations of a preferred tool body in accordance with the
present invention;
Figures 5 and 6 show, respectively, side and underside plan
elevations of a preferred ring for external positioning on
a tool body in accordance with the present invention;
Figure 7 shows an underside plan elevation of a preferred
l0 hole cutter tool when assembled in accordance with t:he
present invention;
Figure 8 shows a partially sectioned side elevation of the
hole cutter tool when assembled, with a drill positioned in
an extended first position and the ring located for a
i5 relatively shallow cutting depth;
Figure 9 shows the tool of Figure 8, but with the drill in
a retracted second position and the ring located for a
relatively deeper cutting depth;
Figure 10 shows a partially sectioned side elevation of an
20 alternative tool to Figure 8 wherein a cutting end of the
tool body is detached therefrom;
Figure 11 shows a side elevation of the cutting end;
Figure 12 shows an underside plan of the cutting end of
Figure 11;
25 Figure 13 shows an assembled side elevation of the tool of
Figures 10 and 11;
Figure 14 shows a partially sectioned elevation of the tool
of Figure 13, illustrating schematically the attachment of
a drill bit within the tool;
30 Figure 15 shows a side elevation of an alternative tool to
Figure 13, in which a cutting end is affixed by means of a
bayonet fitting, the tool in Figure 15 being in a retracted
position;
Figure 16 shows a detail of the tool of Figure 15, but with
35 the tool in an extended position;
Figure 17 shows a plan view of the tool body of Figure 15,
illustrating pins used in the bayonet fitting;
Figure 18 shows an alternative cutting end to that of
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Figure 11: and
Figure 19 shows an assembled partial side elevation of an
alternative tool fitted with the cutting end of Figure 18.
MODES FOR CARRYING OUT THE INVENTION
Referring to Figures 1 and 2, a drill holder 10
for a drill bit 12 (Figures 8 & 9) includes a cylindrical
body 14 having a bore in the form of hollow recess :15
formed therein. A non-cutting end of the drill bit 12 can
be fixed or adhesively bonded (eg. with Loctite TM
adhesive) in the recess 15 to be supported in the holder.
Body 14 further includes a first bore 16 for
fasteningly receiving a pin 17 therein (Figure 7). The pin
17 helps guide the movement of the holder in the tool
(described below). The pin can also be used to fasten the
drill bit 12 in recess 15 (Figures 13 and 14 - described
below). Further, the pin inhibits the rotation of the
drill holder in the tool body (described below).
A second bore 18, opposite to the first bore, is
also formed in the body 14. A ball 19 that is biased by
spring 20 (Figure '7) is positioned in the second bore, and
also helps guide the movement of the holder in the 'tool
(described below).
The holder 10 further includes a circular or
hexagonal shank 21 projecting upwardly from body 14 and
which can be fitted into the chuck of a power drill to
drivingly rotate the holder in use. The shank is typically
circular, triangular or hexagonal in cross-section to
easily fit into and be gripped by a standard chuck.
Referring now to Figures 3 and 4, a tool body 22
includes a cylindrical cavity 24 formed therein. The upper
end of cavity 24 is open for receiving the drill holder
snugly thereinto (Figures 8 & 9). The lower end of the
cavity is closed except at a small cylindrical hole 28,
which opens onto a base 30 of the body. The cavity
diameter is slightly larger than the diameter of the body
14 to facilitate a close but sliding fit therebetween (thus
minimising drill vibration in use).
The dril:L bit 12 extends through hole 28 in use
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(Figures 8 & 9), and shoulders 32, 34 delimit the downward
travel of holder 10 in cavity 24 (Figure 8).
The lower end (base 30) of body 22 has an inset
cutter flange 36 defined thereat. The outer surface of
flange 36 is provided with an abrasive which is typically
formed thereon (eg. a hard wearing metallic or carbide grit
electrically or chE:mically welded, deposited or adhf~red
thereon).
One side of body 22 is provided with a C-shaped
passage 38 which opens out at wall 40 and extends right
through to cavity i?4. The C-shaped passage has an upper
lateral portion 42, a lower lateral portion 44 and an
interconnecting passage 46. On the opposite side of body
22, a longitudinal groove 48 is formed in and opens out at
wall 90, but groove 48 extends only part way into the wall
40 (Figure 4).
Referring to Figures 5 and 6, a ring 50 for
positioning externally on body 22 is depicted. The ring
includes a threaded bore 52 in and through which a threaded
grub screw 59 threadingly extends to protrude into and be
fastened in various positions along passage 48 in use
(Figure 7). The internal diameter of the ring is s:Lightly
larger than the diameter of body 22 to facilitate a snug
sliding of the ring on body 22. The ring is used to control
the depth of the hole cut (described below) or can be
omitted altogether.
Referring now to Figure 7, it can be seen firstly
how the pin 17 protrudes into C-shaped passage 38 to guide
the movement of the drill holder 10 in body 22. Secondly,
it can be seen that: the opposing ball 19 is urged against
the wall of cavity 24 by spring 20, thereby further
facilitating a smooth and balanced movement of holder 10 in
cavity 29 in use. Thirdly, it can be seen how grub screw
54 protrudes into passage 48 to fixedly retain the :ring
externally on body 22 at a desired location.
Figures 8 and 9 show an assembled hole cutter in
the form of tool 70, with the drill holder 10 carrying
drill bit 12 and fitted into the tool body 22. In Figure
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8, the holder 10 is shown positioned right down in the
tool. In this first position, the holder lower end 71
abuts shoulders 32,34. Further, drill bit 12 extends
through passage 28 so that its cutting end 74 protrudes
well beyond the body 22. Further, the pin 17 is urged into
the end 72 of the lower lateral portion 44 of the C--shaped
passage (Figure 8) and is maintained therein in use by the
rotation of the drill holder in a power drive (not shown).
In Figure 8 the ring 50 has been fastened in a
i0 position to provide a shallow cut (ie. to form a shallow
hole - if this is r_equired). However, the ring is often
fastened further up along the wall 40 (eg. as shown in
Figure 9) or may be omitted altogether (eg. where it is
necessary to drill right through a thicker surface),
When the drill holder is rotatingly driven by the
drive (eg. a power drill), the whole assembly 70 rotates
and the drill bit (end 74) can then be urged into a surface
S to drill a pilot hole P (for the subsequently formed hole
H). The advantage of initially using a drill in the cutting
operation is that it can easily penetrate a hard surface
and it at least initially also provides a locating (anchor)
function for the subsequent rotational cutting made by the
flange 36.
Once the drill has penetrated into the surface to
the extent that th<~ flange 36 then engages the surf<~ce at
D, rotation of the tool can be stopped. The drill holder
and drill can then be retracted into the tool by moving the
pin 17 in the C-shaped passage, firstly into passage 46 and
thence into upper :Lateral portion 42 (Figure 9). During
this movement, the holder lower end 71 no longer abuts or
faces shoulders 32,,34 and the holder is then moved :freely
upwards in the cavity 24.
Further rotation of the drill holder by the drive
maintains the pin at end 76 of passage 42 and enables the
cutting of hole H. Whilst the drill cutting end can be
partially, substantially or entirely retracted into the
tool in Figure 9 it can also be withdrawn to a position
where it assists with the abrasive at flange 36 to cut the
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(Fig
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hole. Also, when the end is still slightly protruding it
can be relocated .into the pilot hole to assist with
progressive cutting' of the hole. Also, as the tool i.s
advanced into the surface to cut the hole H, the ring 50
(now at a different location) eventually engages the: skin
of the surface at D and thus prevents further tool
advancement.
In another embodiment, the grub screw can be
sized such that it enables the ring to travel up along tool
body at wall 40 ( ~.e. with grub screw 54 travelling i.n
groove 48). In this latter embodiment, with further tool
advancement, eventually the grub screw reaches the t:op of
groove 48 (or a stop formed or positioned therein) and thus
ring travel is halted. The ring then prevents further
advancement of the tool into the surface, and signals
completion of the hole cutting operation.
In either case, once the ring has prevented
further tool advancement, the tool can then be withdrawn
from the newly formed hole, and the drill holder returned
to the position of Figure 8 for cutting of further holes.
The ring arrangement thus controls the depth of the hole
cut (eg. to prevent: a hole being cut right through a
surfcraft), thereby functioning as a depth gauge. Of
course, where hole depth is not relevant the ring can be
removed from the pool.
Referring now to Figures 10 to 14, where like
reference numerals will be used to denote similar oz. like
parts, an alternative tool 70' has a modified tool body 80.
As can be seen, the lower open end 82 of body 80 is
internally threaded at 84. A detachable cutter end 86 has
external threads 88 formed therearound for threadably
engaging internal threads 89. In other words, the cutter
end can be screwed onto and unscrewed from body 80. The
cutter end has an abrasive surface 90 formed thereon (as
per the tool of Figure 8). The diameter of the abrasive
end 90 can be varied to cut different sized holes. In
other words, a cutter end with a different diameter cutting
surface can readily replace an existing cutter end attached
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to body 80. As can be seen, the cutter end is provided
with a bore 92 through which the drill bit 12 extends
(Figures 13 and 14).
As seen in Figure 12, a transverse passage 94 can
be provided in the underside of the cutter end for
releasing debris that is distributed to the underside of
the cutter end by drill bit 12 during use of the device.
Referring to Figures 13 and 14, it can be seen
how pin 17 can be screwed right through from the exterior
l0 of the tool to engage against and fasten drill bit 12 in
drill holder 10. The pin 17 can be provided in the form of
an allen screw 17 for its ready tightening and
untightening. The operation of the tool 70' is in all other
respects similar t::a the operation of the tool of Figure 8.
IS Referring now to Figures 15 to 17, like reference
numerals will be used to denote similar or like parts to
the tools of Figures 1 to 14. In this embodiment, the
cutter end 86', rather than having an externally threaded
section 88 has a pair of opposing L-shaped slots 100 formed
20 therein, and into which a pair of opposing bayonet pins 102
are respectively z°eceived. In other words, attachment of
cutter end 86' to tool 70" is facilitated by pushing on
and then rotating the end so that the pins are moved. into
and abut the end of each slot 100 (as shown in Figure 15).
25 An additional safe fastening of the cutter end 86' to body
80 can be facilitated by screwing an allen grub screw 104
through body 80 and into engagement with the cutter end. In
all other respects, the tool 70" of Figures 15 to 17
functions in a similar way as the tool of Figure 8.
30 Referring now to Figures 18 and 19, an
alternative detachable cutter end 120 includes a fructo-
conical cutting surface 122 with an insert shank 129
extending upwardly therefrom. The drill (not shown) extends
out of lower opening 126. A pair of opposing threaded holes
35 128 are formed in the shank and are each adapted for
threadably receiving the end of a respective locking screw
130 therein.
In Figure 19, it will be seen that cutter end 120
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fits snugly within modified tool body 132, with shank 124
extending up into body cavity 134. The cutter end is
positioned such that holes 128 align with respective
countersunk holes 136 formed in body 132. A countersunk
screw 130 can then be screwed in to each aligned hole pair
to releasably fasten the cutter end in place in the tool
body.
Preferably a pitch is employed on the cutter end
as shown, to further facilitate the drilling action of the
cutting tool. Typically a 9mm pitch is employed.
It should be noted that with both the tool. 70'
and the tool 70" , the orientation (sense) of the threads
89, 88 and of the pi_n and slots 100, 102 is selected such
that when the cutter. head engages against the surface in a
IS cutting operation, t:he threads are tightened or the pin is
maintained in the end of its respective slot. In other
words, the cutting action prevents the cutter end from
detaching from the body 80. This feature can also be used
to remove the cutter_ end from the body 80 (eg. wherE: the
power drive has a reversible function). In this case, the
direction of tool notation can be reversed and the tool can
be urged against a surface to unscrew threads 84, 88 or to
move pins 102 out of slot 100.
Typically all of the components of the tool are
formed from metal ;eg. steel, steel alloys, aluminium,
copper etc) or other strong and hard wearing materials.
Plastic may be employed in some situations for certain
components (eg. body 22 or holder 10).
Typically drill holder 10 is moved manually in
the tool between the positions of Figures 8 and 9.
However, other mechanisms, such as an oppositely acting
thread system between the holder and the body (eg. opposing
the drive rotational sense), or a gear driven drill (eg. a
rotating gear acting on a rack on the drill holder) can
also be employed. The manual arrangement is most preferred
because it is robust and simple in construction and use.
Whilst the invention has been described with
reference to a number of preferred embodiments, it should
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be appreciated that the invention can be embodied in many
other forms.
