Note: Descriptions are shown in the official language in which they were submitted.
CA 02555533 2006-08-08
~
TITLE: IIAMMEkt Dk2ILL BIT CHUCK ATTACHMENT
INVENTOR: FERN BEA.UCHAMP
CA 02555533 2006-08-08
FIELD OF THE INVENTION
[0001] The present inventiori relates to hammer drills, and more
particularly to hammer drill bit chuck attachments.
f3ACKGROUNA OF THE INVENTION
[0002] Fiammer drills are well known and 3re typicall y used, even
by home c-r a ftcmon, tcr.. i.. .~~ ..,.~... ~,~ ~.,~....~ ,,..'!.Y . ._. ,
such as concrete and tho like. Such hammer drills typically have
a rotating spindle that drives the drill chuck. A fixed disc
having a rearwardly facing toothed. surface is secured to the
rotations spindle. A, movable disc having= a forwardly facing
toothed surface is selectively engageable with the rearwardly
facing toothed surface of the fixed disc: so as to provide the
hammer drill funct_ion. Althoiigh the apparatus does work, it
presents a serious drawback in that the impact created by the
engagement of the two toothed surfaces is directcd forwardly
through the drill bit and aJ.so back through the drill itself, as a
reaction force. Accordingly, the bearings of the drill tend to
wear excessively, which is highly undesi.rablc. Further, it is well
known that there can be significant heat build with prior art
hammP,r, drills.
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[0003] Such hammer drills, also known as percussion drills, can
be found in for example United S1:ates Patent 2, 942, 852, issued June
28, 1960 to Muthmari arnd Usiited States Patent 5, 653, 294, issued
August 5, 1997 to Thurler.
[0004] United States Patent 4,450,919, issued Ma.y 29, 1984 to
Cousineau discloses a drill attachment for use with a conventional
electric drill. This drill attachment provides a hammering and
drilling action so that a conventional drill may be used to drill
into hard substances. The d.r.i.ll, attachment comprises a hammer
assembly having a rearward case and a forward chuck assembly. A
rotating spindle is mounted within the case and has a reciprocating
spindle moui'ited irl tkie front end thereof. The rotating spindYe
drives a drill chuck wzthin the chuck assembly via the
reciprocating spindle. A rotating ciutch plate mounted on the
reciprocating spindle rotates with the reciprocating spindle.
Teeth on the rotating clutch plato engage cooperating teeth on the
stationary clutch that is securely mounted on the case. A
rcmovable handle connected to the case permits the case, and
therefore the stationary clutch, to be selectively moved forwardly
such that the teeth of the stationary clutch engage the teeth of
the rotating clutch plate, to thereby impart the hammering function
to a drill bit retained within the bit chuck. The reaction force
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is not transiuitted back through the drill itself, buL is
transmitted to the handle, thus saving wear on the bea.r.i,ngs of the
drill. However, the above described drill attachmexit; is far more
complicated and rar more expensive than is necessary.
t0005] ft is a further object of the present invention to
provide a simplifi.ed hammer drill bit chuck attachment.
[0006] It is yet a further object of the present iriventi.on to
prov.id.e a simplified hanuner dLill biL c:liuck attacnment tnat is
inexpensive to manufacture.
[0007] It is yet a further object of the present invention to
provide a simplified hammer drill bit chuck attachment Lhat is
robust.
[0008] It is yet a further object of the. present invention to
provide a simplified hammer drill bit chuck attactunPnt wherein the
frequency and ampJ.itude of impacts can be adjusted or selected_
[0009] It is yet a further object of the present invention to
provide a Simplifi.ed hammer drill bit chuck attachmerit wherein heat
build up is minimized.
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[00010] It is yet a further object of the present invention to
provide a hamnier drill bit chuck attachment wherein an electric
drill used in cronjunction with the hammer drill bit chuck
attaclunent can be operated at lower rotational speeds.
SGMMJARY OF THE INVENTION
[00011) In accordance with one aspect of the present invention
there is disclosed a novel hammer drill bit chuc.k attachment
comprising a main shaft having a forward drill chuck end portion
and a rearward shank portion, and defining a longitudinal axis. An
impact member is mounted in fixed relation on the main shaft for
rotation therewith. An actuator mechanism is mounted on the main
shaft for free rotation of the ma.a.n shaft with respect to the
actuator mechanism and for longitudinal sliding movernent of the
actuator mechanism alorig the main shaft between -a forwardly
displaced posiLion and a rearwardly displaced position. At least
one impact portion is disposed on one of the impact member and the
actuator mechanism. At least one roller member is 'rotaLionally
mounted on the other of the impact member and the actuator
mechanism. Rotation of the main shaft and impact member about the
longitudinal axis when the actuator mechanism is in force
Lransmitting engagement with the impact member, causes the actuator
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mechanism to move in a reciprocating motion between the forwardly
displaced position and the rearwardly displaced position, and
transmits impact forces forwardly along the longitudinal axis to
the main shaft.
[00012] Other advantages, features and characteristics of the
present invention, as well as methocis of operation and functions of
the related elements of the structure, and the.combination of parts
and economies of manufacture, will become more apparent upon
consideration of the following detailed description and the
appended claims with reference to the accompanying drawings, the
latter of which i5 briefly described herein below.
BRIEF DESCRIPTION OF THE DRAWINGS
1000131 The novel. features which are believed to be
characteristic of the hammer dril], bit and hammer drill bit chuck
attachment according to the present invention, as to its structure,
organization, use and method of operation, together with further
objectives and advantaqes thereof, will be better understood from
the following drawings in which a presentl.y preferred embodiment of
the invention will now be ill.ustrated by way of example. It is
expressly understood, however-, L=hat the drawings are for the
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purpose of illustration arid description only, and are not intended
as a definition of the limits of the invention. In the
ac:companying drawings:
[00014] Figure 1 is a perspective view from the front of the
first preferred embodiment of the hammer drill bit uhuck attachment
accordinq to the present invention;
[00015] Figure 2 is a perspective view from Lhe rear of the first
preferred embodiment hammer drill bit chuck attachment of Figure 1;
[00016] Figure 3 is an exploded perspective view from the front
of the first preferred embodiment hammer drill bit chuck attachment
of Figure 1;
[00017] Figure 4 is an exploded perspective view from the rear of
the first preferred embodiment hammer drill bit chuck attachment of
Figure 1;
[00018] Figure 5 is an enlarged exploded perspective view from
the front of a portion of the second preferred embodiment hammer
drill bit chuck attachment of Fi.gure 1;
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[00019] Figure 6 i.s an enlarged exploded perspective view from
the back of a portion of the second preferred embodiment hammer
drill bit chuck attachment of Figure 1;
[00020] Figure 7 is a side elevational view of the hammer drill
bit chuck attachment of Figure 1, but with the actuator mechanism
in a fully forward position;
[00021] k'a.gure B is a perspective vi.ew f.rom the rear of the
hammer drill bit chuck attachment as shown in Figure 7;
100022) Figure 9 is a side elevational view similar to Figure 7,
but with the actuator mechanism in a diserigaged positiori;
[00023] Figure 10 is a pcrspective view from the front of a
second preferred embodiment of the ha.mmer drill bit, chuck
-attachment according to the present.invention;
[00024] Figure 11 is a perspective view of a portion of the
second preferred ezn.bodiment of the hammer drill bit chuck
attachment of Figure 10;
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[00025] Figure 12 is a perspective view from the fraiit of the
third preferred embodiment of the hammer drill bi't chuGk according
to the present invention, without a drill chuck in place;
[00026] Figure 13 is a perspective view from the rear of the
third preferred ernbodimerlt hammer drill biL chuck of Fiquxe 12;
[00027] Vigure 14 is a side elevationa.l., view of the third
preferred embodiment hammer drill bit chuck of Figure 12, with the
actuator mechanism in its engaged position;
[00028] Figure 15 is a side elevational view of the third
preferred embodiment hammer drill bit chuck of Figure 12, with the
actuator mechanism in its disengaged position;
[00029] Figure 16 is a rear elevational view of the third
preferred embodiment hammer drill bit chuck of Figure 12;
[00030] Figure 17 is an exploded perspective view from the fron-C
of the third preferred embodiment hammer drill bit chuck of Figure
12;
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{00031] Figure 18 is an exploded perspective view from the rear
of the third preferred embodinient hammer drill bit chuck of Figure
12;
[00032] Figure 19 is an exploded side elevational view of the
third preferred embodiment hammer drill bit chuck of Figure 12;
[00033] Figure 20 is a perspective view from the front of the
third preferred embodiment hammer drill bit chuck of Figure 12,
without a drill chuck in place;
[00034] Figure 21 is a perspective view from the rear of the
third preferred embodiment hammer drill bit chuck of Figure 12;
[00035) Figure 22 is a perspective view from the rear of the
third preferred embodiment hammer drill bit chuck of Figure 12,
showing i:he _actuator collar;
[00036] Figure 23 is a perspective view from the rear of the
third preferred embodiment hammer drill bit chuck of Figure 12,
showing the sLationary toothed collar and the elongate main shaft;
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[00037] Figure 24 is a end elevational view of the third
preferred embodiment hammer drill bit chuck of Figure 12, showing
the actuator r_ol lar. ;
[00038] Figure 25 is a perspective view fron- the front of an
alternative embodiment of the hammer drill bit chu.ck accordinq to
the present invention;
1000391 Figure 26 is an exploded perspective view from the front
of the fourth preferred embodiment of the hammer drill bit chuck
according to the present invention;
[00040] Figure 27 is an exploded perspective view from the rear
of the fourth preferred embodiment of Figure 26;
100041] Figure 28 is a cross-sectional view of the fourt;h
preferred embodimeilL of Figure 26, in place on a drill chuck; and,
[000421 Figure 29 is a cross-sectional view of the fourth
preferred embodinient of Figure 26, withouL the drill chuck.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
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[000431 Referring to Figures 1 through 29 of the drawings, it
will be noted that Figures 1 through 9 illust_rate a first preferred
embodiment of the hammer drill bit chuck attachment of the present
invention, Figures 10 and 11 illustrates a second preferred
embodiment of the hammer drill bit chuck attachment of the present
invention, Figures 12 through 25 illustrate a third preferred
einbodiment of the hammer drill bit chuck attachment of the presenL
invention, and 26 through 29 illustrate a fourth preferred
embodintent of the hammer drill bit chuck attachment of the present
invention.
[000447 Reference will now be made to Figures 1 through 9, which
show a first preferred embodiment of the hammer drill bit chuck
attachment of the present i.nvenT_ion, as indicated by general
reference numeral 120. The hanuner drill bit chuck attachment 120
compzises a main shaft 7.30 having a threaded forward drill chuck
end portion 132, an intermedaate i:mpac:t member receiving portion
~= ..
133, and a rearward shank portion 134. The main shaft 130 defines
a longitudinal axis "L" about which the main shaft 130 rotates.
~= ,.
[00045] A drill. bit chuc_k 135 is mountable on the forward drill
chuck end portion 132 of the main shaft 130 for rotation therewith,
as can be best seen in Figures 1 and 2. The dri I.I. bit c:huc:k 135 is
a conventional drill bit chuck and c;otnprises three movablP jaw
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members 136 that receive and retaiil a conventional drill bit 129
therein. A ferrule member 137 surrounds the jaw members 136 and is
wedged between the jaw members 136 and an outer housing 138 to keep
the jaw members 136 locked in place on the conventional drill bit
129. A base meiiLber 139 is secured in place within the outer
housing 138 and the back end 136b of the jaw members 136. The base
member 139 has a threaded bore hole 139a that receives a co-
operating threaded forward portion 134a of the rearward shank
portion 134 i.n.secure engagement. Fundamentally, the hammer drill
bit chuck attachment 120 comprises a main shaft 130, an impact
member 190 and an actuator mechanism 150, as wil]. be described in
greater detail below.
[00046] An impact member 140 comprises a main. body portion 142,
a forwardly facing surface 145, a rearward fac.:inc~ surface 146 and
at least one impact portion. Alternatively, the at least one
i_mpact member can be mounted on the actuator mechanism 150. In the
first preferred embodiment, as illustrated, the at least one impact
portion comprises a plurality of impact portions 149. As can be
readily seen in the figures, the plurality of impact portions 149
comprise a plurality of impact protrusions 149. Alternatively, it
is contempiated that the pluraliL"y of impact portions could
comprise a plurality of impacL- indentations. As illustrated, there
are twenty-four impact protrtisions 1,49 substantially evenly spaced
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around the rearwardly facing surface 146 of the impact member 140.
Alternatively, ther.e can be any suitable number of impact portions.
[00047] The itnpac:t inember 140 is mounted in fixed relation on
the main shaft 130 for rotation therewith, and projects radially
outwardly from the intermediate irapact member receiving portion
133. The impact member 140 is threadibly engaged on the
intermediate i.mpact member receiving portion 133 the main shaft
130. The threads on the forward drill chuck end portion 7.32 and
the intermediate impact member receiving portion 133 are
co-operatingly aligned with each other such that the impact member
140 can be threadibly engaged from the forward drill chuck end
portion 132 to the intermediate impact member receiving portion
133. The rearward facing impact surface 146 may be integrally
formed ori L.he ma.in body portion 142, or alternatively, as shown in
Figures 10 and 11 may be formed on a rearward ring member 145. The
alternative embodi.ment as shown in Figure 10 also shows a
protective sheath 147 disposed over the actuator mechanism 150.
The protective sheath 147 is preferably made rrom a suitable
plastic material and is overmolded over the ,actuator mechanism 150.
The plastic protective sheath 10 irisulates an operator's hand from
potential electric shock i.f the drill bit 129 happens Lo conLact a
live electrical wire during drilling.
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[000481 The rearward facing impact surface 146 has a plurality of
radially directed teeth 148 that are substantially evenly spaced
around the rearward facing impact surface 146. Alternatively, the
radially directed teeth 148 of the rearward facing impact surface
146 may be irregularly spaced, or spaced apart in any other
suitable manner.
[00049] An actuator mechanism 150 comprises a main body member
152, a forwardly facing surface 156 and a rearwardly facing surface
155. The actuator mechanism 150 is mounted on the main shaft 130,
mostly at the rearward shank portion 134 rearwardly of the impact
member 140, for free rotation about the main shaft 130 and for
lonqitudinal s].a.dinq movement along the main shaft 130. In the
preferred embodiment, as illustrated, the actuator mPc:hanism 150 1.s
retained on the rearward shank portion 134 by means of d"C"-clip
160 securely eriqaged in an aruiular slot 162 in the rearward shank
portion 134,. Other stiitable means may a.iso be used.,. The section
of the rearward shank portion 134 disposed rearwardly of the impact
member 140 tuust_ be of sufficient length to be securely received in
the bit chuck of a conventional electric drill.
[00050] At least one roller member, and in the first preferred
embodiment as a..l.l.ustrated, a plurality of roller members
(specifically three roller members 160), are rotationally mounted
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on the main body member 152 of the actuator mechanism 150 by means
of mounting pins 161 press fit into cooperating apertures 153 in
the main body member 152. Alternatively, the roller members 160
could be mounted on the impact member 140. The axis of rotation
"R" of each roller member 160 is substanti.a]..ly perpendicular to the
longitudinal. axis "L" of the main shaft 150. The roller member.s
160, as illustrated, are bearing assem.blies having an outLer ring
freely rotatably mounted onto an inner hub. other suitable designs
of roller members 160 could also be used.
[00051] The actuator meChanism 150 is mounted on the rearward
shank portion 134, as described above, in freely rotatable relation
on the main shaft 130 for rotation about the rearward shank port_ion
134 and for longitudinal s].idi.ng movement along the main shaft 130
between a forward forwardly displaced position, as is best seeri in
Figures 7 and 9, and a rearward rearwardly displaced position, as
is be:;t: seen in. Figure 8. The "C"-clip 160 defines the rearward
rearwardly displaced position of the actuator collar.
[00052] A manually manipulable handle 1.70 is removably connected
to the actuator mechanism 150 by means of a threaded shaft 172
threadibly engaged in a co-operating thr-edded bore hole 151_ The
handle 170 permits manual manipulation of the actuator mechanism
150 by a user's hand, so as to cause the longitudinal sliding
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movement of the actuator mechanism 150 belween the forward
forwardly displaced position and the rearward rearwardly displaced
position. The manually manipulable handle 170 is preferably made
from a suitable plastic material in order to insulate an Uperator's
hand from potential electric shock if the driil bit 129 happens to
contact a live clectrical wirc during drilling.
[00053] The rearward shank portion 134 merely freely rotates
within the actuator mechanism 150. When the manually manipulable
handle 170 is not held by a user, the actuator mechanism 150 e3Tld
thc handle 170 do not rotate with the rearward shank portion 1.34,
but remain essentially in one position due to the weight of the
handle 170.
[00054] Rotation of the main shaft 130 and the impact member 140
abouF the longitudinal axis "L" when the actuator mechanism is in
its forwardly di.splaced position; the roller members 160 engage thc
plurality of impact protrusions 149 on the rearward facing impact
surface 1.46 of the impact member 140 as the main shaft 130 rotates
wiLh respert to the actuator mechanism 150, as would occur during
normal use of an electric drill (not shown) The actuator
mechanism 150 is thereby caused to move in a reciprocating motion
between its forwardly displaced position and its rearwardly
displaced position. In this manner, the roiler members 160 impart
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reciprocating motion along the longitudinal axis "L" to the main
shaft 130, to thereby transmit impact forces forwardly along the
longitudinal axis "L" to the main shaft 130, and therefore to the
conventional drill bit 129. It would be readily understood by one
skilled in the art that the roller members 160 generally ride along
the rearward facing impact surface 146, and may i,mpact all of the
impact protrusions 149, or impacts only higher portions of the
impact protrusions 149, depending on the speed of rotation of the
impact member 140 with respect with the actuator mechanism 150.
[00055] The height, radius of curvature, shape and number of
teeth 148 will affect the frequency and amplitude of the impacts of
L-he roller members 150 on the rearward facing impact surface 146.
[00056] As can be readily seen in Figure 10, the rearward ring
member 145 maybe set permanently in place by means of press-fitting
or screw-fitting, or both, or maybe removably and replaceable so as
to allow an end user to select the frequency and amplitude of
impacts, as desired.
, ,. ~.
[00057] As described above, the conventional drill bit 129 is
caused to "hammer" into a piece of material a5 it rotates, thus
causing a drill hole to be drilled readily even into hard
materials, such as cement or concrete. It should also be noted
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that the electric drill itself does not absorb the reaction of the
impact of the roller members 160 on the teeth 148 of the rearward
facing toothed surface 146.
(00058} A spring means 170 is operatively mourited between the
actuator mechanism 150 and the main shaft 130 for biasing the
actuator mechanism 150 to the forward forwardly displaced position.
More specifically, the spring means 170 comprises a coil spring 170
that is operatively mounted between the actuator mechanism 150 and
the impact member 140 through the main shaft 130. The back end of
the coil spring 170 bears against a washer 153, which itself bears
against the "C"-clip 160. The front end of the coil spring 170
bears against a roller bearing 151 securely seated within the
actuator mechanism 150. in this manner, the coil spring 170 biases
the actuator mechanism 150 through i.ts forward forwardly displaced
position. Accordingly, when the elongate main shaft 30 and the
impact member 140 are rotated, the actuator mechanism 150 is
rotated therewith. In use, the actuator mechanism 150 is moved
slightly rearwardly to its forward forwardly displaced position
against the force of the cozl spring 170. Further rearward
movement of the actuato.r, mechanism 150 will caiise the actuator
mochanism 150 to move to its rearwardly displaced position.
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[00059] In an alternative embodiment of the present invention
(not illust:rated), it is contemplated that a spring could bias the
actuator mechanism 150 to it5 rearwardly displaced position.
Accordingly, the actuator mechanism 150 does not rotate, or at
least not subst.antially so, when the main shaft. 130 is rotated
during use. This is advantageous in that when the actuator
mechanism 150 is grasped by an operator for use, it is not
rotating, and is therefore more readily grasped.
[00060] It has been found that with the hammer drill bit chuck
attachment 120 of the present invention, there is reduced friction,
reduced heat build up, reduced wear and improved drilling
performance compared with conventiorial hammer drills, which have
two sets of impacting steel teeth used to perform the hammering
fun.ction. IIeat build up is of particular concern uiider IEC
60745-1:2001, as adopted by UL, CSA and other national governing
bodies regulating safety iri hand held power tools and accessories.
~. ,
An electric drill using the present invention experiences very
minimal loss of speed due to the reduced friction between the
roller members 150 and the impact member. Accordingly, the
rotational energy is d-i-rected to the actual longitudina]. vibration,
and not to losses due to friction and heat. This is important for
being able to achieve the maximum possible speed with a drill, and
also for reduced wear of the hammer drill bit chuck attachment of
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the present invention and an electric drill being used. In
contrast, an electric hammer drill actually operates at a
significantly reduced rotational speed compared to the maximum
rotational speed of the drill, due to the friction of the steel
teeth.
[00051] Reference will now be made to Figures 10 and 11, which
show a second preferred embodiment of the hammer drill bit chuck
attachment of the present inven-tion, as indicated by general
reference numeral 220. The second preferred embodiment hammer
drill bit chuck attachment 220 is similar to the first preferred
embodiment hammer drill bit chuck attachment 120 except that the
rearward facing impact surface 246 is formed on a rearward ring
member 245 that is secured to the main body portion 242. The
rearward ring member 245 may be set permanently in place by means
of press-fitting or screw-fitting, or both, or maybe removably and
replaceable so as to allow an end user to select the frequency and
amplitude of impacts, as desired. The second preferred embodiment
also shows a protective sheath 247 disposed over the actuator
mechanism 250. The protective sheath 247 is preferably made from
a suitablQ pla9tic mate.r.i.al. and is overmolded over the actuator
mechanism 250. The plastic protective sheath 247 insulates an
operator's hand from potential electric shock if the drill bit (not
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specifically shown) happens to contact a live electrical wire
during drilling.
j00062] Reference will now be made to Figures 12 through 25,
which show a third preferred embodiment of the hammer drill biL
Chuck attachment of the present invention, as indicated by general
reference numeral 320. The haznmer drill bit chuck attachment 320
comprises a main shaft 330 having a threaded forward drill chuck
end portion 332, an intermediate impact member receiving portion
333, and an elongate rearward shank portion 334. The main shaft
330 defines a longitudinal axis "L" about which the main shaft 330
rotates.
[00063] A drill bit chuck 335 is mountable on thp threaded
forward drill chuck end portion 332 for rotation therewith. The
drill bit chuck 335 is preferably a conventional drill bit chuck
and comprises three movable jaw members 336 that receive and retain
a conventional drill bit 329 therein. A ferrule member 337
surrounds the jaw members 336 and is wedged between the jaw members
336 and an outer housing 338 to keep the jaw members 336 locked in
place on the conventional drill bit 329. A base member 339 is
secured in place within the outer housing 338 and the back end 336b
of the jaw members 336. The base member 339 has a threaded bore
hole 339a that receives a co-operating threaded forward portion
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334a of the rearward shank portion 334 in secure engagernent.
Fundamentally, the hammerdrill bit chuck attachment 320 comprises
a main shaft 330, an impact member 340, and an adapter mechanism
350, as will be described in greater detail below.
[00064) An impact member 340 comprises a main body portion 342,
a forwardly facing surface 345 and a rearwardly facing surface 346,
and at least one impact portion. Alternatively, the at least one
impact member can be mounted on the actuator mechanism 350. In the
third preferred embodiment, as illustrated, the at least one impact
portion comprises a plurality of impact portions 348. As can be
readi.ly seen in the figures, the plurality of ball bearings 348
rotatably mounted in the rearwardly facing surface 346 of the
impact member 340. Alternatively, it is contemplated that the
plurality of impact portions could comprise a plurality of impact
indentations. As illustrated, there are twenty-four impact
protrusions 348 substantially evenly spaced arouzid 4he rearwardly
t ~.
facing surface 346 of the impact member 340. A1ternatively, there
can be any suitable number of impact portions.
,. .
[00065] The impact member 340 is mounted in fixed relation on
the main shaft 330 for rotation therewith, and projects radially
outwardly from the intermediate impact member receiving portion
333. The impact n mber 340 is slid over the elongate rearward
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shank portion 334 and is press-fit onto the intermediate impact
member receiving portion 333 of the main shaft 330. The
inter-mediate impact member receiving portion 333 is a few
thpusandths of an inch larger in diameter than the elongate rear
shank portion 334_
[00066] An actuator mechanism 350 having a forwardly facing
surface 356 and a rearwardly facing surface 355 is mounted in
freely rotatable relation on the zearward shank portion 334 of the
main shaft 330, immediately rearwardly of the impact member 340,
for free rotation about the rearward shank portion 334 and for
longitudinal sliding movement along the rearward shank portion 334.
In the preferred embodiment, as illustrated, the actuator mechanism
350 is retained ori the rearward shank portion 334 by means of a
"C"-clip 360 securely engaged in an annular slot 362 in the
rearward shank portion 334, that bears against a washer 361. A
second annular slot 362 is also included. Other suitable means may
also be used. The section of the rearward shank portion 334
disposed rearwardly of the actuator mechanism 350 must be of
sufficient length to be securely received in the bit chuck of a
conventional electric drill.
[00067] The actuator mechanism 350 is mount.ed on the rearward
shank portion 334, as described above, for free rotation about the
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rearward shank portion 334 and for longitudinal sliding movement
albng the rearward shank portion 334 between a forward forwardly
displaced position, as is best seen in Figures 12, 13, 14, 20 and
21, and a rearward rearwardly displaced position, as is best seen
in Figure 28. The "C"-clip 360 defines the rearward rearwardly
displaced position of the actuator collar.
[00068] The actuator mechanism 350 has at least one roller
member rotationally mounted thereon, and in the third preferx-ed
embodiment as illustrated, has at least one ball bearing 358
mounted thereon. More specifically, the at least one ball bearing
350 cornpr.a.ses a plurality (specifically twelve) ball bearings 358
roi:ationally mounted in, the forwardly facing surface 356 of the
actuator mechanism 350. The ba'll bearings 358 are rotationally
mounted and otherwise positioned to engage the ball hearings 348 in
the impact member 340, as will be discussed in greater detail
subsequently.
[00069] The ball bearings 358 in -the actuator mechanism 350 and
the ball 2?earings 348 in the impact member 340 are, each mounted
within a co-operating cylindrical recess 349,359 having a diameter
slightly greater than the diameter of the ball bearings 348, 35E3,
and a depth slightly less than the diameter of the ball bearings
348,358, so that the ball bearings 348,358 project outwardly from
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t-he cooperati.ng recesses 349,359 respectfully. Preferably, the
ball bearings 348,358 are each mouriL-ed within the co-operating
recesses 349,359 by means of a suitable grease type material, so as
to help retain the ball bearings 348,358 in place.
[00070I It has been found that ball bearings 348,358 having a
diameter of about 5/16" are suitable, although other sizes of ball
bearings 348,358 could also be used. It has also been found that
the ball bearings 348,358 of about this size should protrude beyond
the rearwardly facing surface 346 of the impact member 340 and the
forwardly facing surface 356 of the actuator mechanism 350, as the
case may be, by up to about 0.050", or even more, and preferably by
about 0.025", depending on the diameter of the ball bearings
348,358. Although the ball bearings 348 and the ball bearings 358
are shown to be the same diameter as each other, this is not
absolutely necessary.
[00071] As can be seen in the Figures, there is also an optional
elongate bore hole 353 in communication with each recess 359 in the
actuator mechanism 350, for permitting the ball bearings 358 t~o be
readily removed.
[00072] Rotation of the main shaft 330 and the impact member 340
about the longitudinal axis "L" when the actuator mechanism 150 is
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CA 02555533 2006-08-08
in its forward forwardly displaced position, causes the bal,7.
bearings 358 in the actuator mechanism 350 are in engagement with
the ball bearings 348 (the impact portions) of the impact member
340 as the rearward main shaft 330 is rotated. The ball bearings
358 in the forwardly facing surface 356 of the actuator mechanism
350 quickly impact the ball bearings 348 in the rearwardly facing
surface 346 of the impact member 340, as the main shaft 330, and
therefore the impact member 340, is rotated by the conventional
electric drill 322. The actuator mechanism 350 Is thereby caused
to move in a reciprocating motion between its forwardly displaced
position and its rearwardly displaced position The actuator
mechanism 350 thereby imparts reciprocating motion along the
longitudinal axis "L" to the drill bit chuck 335, to thereby
transmit impact forces along the longitudinal axis "L" to the main
shaft 350, and therefore to the conventional drilJ. bit 329 retained
therein. In this manner, the conventional drill bit 329 is caused
to "hammer" into a piece of material as it rQtates, thus causing a
drill hole to be drilled readily even into hard materials, such as
cement or conC:rrm.tP- 'T'ha nltiral -ii-v r~-F 1na11 }oarir~rJa 4R earyd 358
_,-$,
each rotationally mounted in evenly radially spaced relation around
the longitudinal axis "L" to provide for an even impacting action.
It should also be noted that the drill 322 itself does not absorb
the reaction of the impact of the ball bearings 358 of the actuator
mechanism 350 on the ball bearings 348 of the impact member 340.
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CA 02555533 2006-08-08
[000731 In the rearward rearwardly dasplaced position, the ball
bearings 358 of the actuator mechanism 350 are removed from the
rotational engagement with the ball bearings 348 of the impact
member 340. The rearward shank portion 334 of the main shaft 330
merely freely rotates within the actuator mechanism 350, or
alternatively, the actuator mechanism 350 merely freely rotates
around the rearward shank portion 334 of the main shaft 330.
[00074] The third preferred embodiment hammer drill bit chuck
attachment 320 further comprises an insulating cover 351
. ~.
peripherally surrounding the actuator mechanism 350. Preferably,
the insulating cover 35:E. j,s made from a synthetic rubber or plastic
material, and is overmolded oti the actuator mechanism 350. The
i.nsulating cover 351 is used to electrica.lly insulate the actuator
mechanism 350 from a user's hand, when a user grasps the actuator
mechanism 350 during use to preclude the actuator mechanism 350
from turning with the impact member 340, . thus allowing the ball
bearings 358 on the actuator mechanism 350 to impact the ball
bearings 348 on the impact member 340, thereby imparting
reGiprocating motion along the long~tudinal axis "L" to the main
shaft 330. It has been found that grasping the insulating cover
351 permit for the accurate application of manual force along the
longitudinal axis "L".
-
- 27
CA 02555533 2006-08-08
[000751 It can also be seen that the third preferred embodiment
hammer drill bit chuck attachment 320 permits bi-d.i-rectional
rotational operation of the elongate main shaft 330 and therefore
the forward drill bit portion 332, although it would not be overly
common to require the third preferred embodiment hammer drill bit
320 to operate it the reverse direction.
[00076) In an alternative embodiment, a shown in Figure 25, it is
contemplated that a manually manipulable handle 370 is removably
connected to the actuator mechanism 350 -by means of a threaded
shaft 372 threadibly engaged in a co-operating threaded bore hole
371. The handle 370 permits manual manipulation of the actuator
mechanism 350 by a user's hand, so as to cause the longitudinal
sliding movement of the actuator mechanism 350 between the forward
forwardly displaced position and the rearward rearwardly displaced
position. When the manually manipulable handle 370 is not held by
a user, the actuator mechanism 350 and the handle 370 do not rotate
with the main shaft 330, but remain essenti.ally in one position due
to the weight of the handle 3'10.
I.
Reference will now be made to Figures 26 through 29,
which shows a.f.ourth preferred embodiment of 'the hammer drill bit
chuck attachment of the present invention, as indicated by general
reference numeral 420. The fourth px'eferred embodiment of the
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CA 02555533 2006-08-08
hammer drill bit chtick attachment 420 is similar to the third
preferred embodimerit of the hammer drill bit chuck attachment 320,
except for the inclusion of a spring means 470 operatively mounted
between the actuator collar 450 and the elongate main shaft 430 for
biasing the actuator collar 450 to the forward forwardly displaced
position. More specifically, the spring means 470 comprises a coil
spring 470 that is operatively mounted between the actuator collar
450 and the stationary toothed collar 440. The coil spring 470
sits within a recess 452 in the back end of the actuator collar
450, and surrounds the back end of the shank portion 434 of the
elongate main shaft 430. The coil spring 470 bears against the
forward end 452a of the recess 452 and also bears against a washer
453, wliich itself bears against the "C"-clip 460. In this manner,
the coil spring 470 biases the actuator collar through its forward
forwardly displaced position and to its fully forward position.
Accordingly, when the elongate main shaft 430 and the stationary
toothed collar 440 are rotated, the actuator collar 450 zsrotated
therewith. In use, the actuator collar 450 is moved slightly
rearwardly to its forward.forwardly displaced position against the
force of the coil spring 470.
[000781 As can be understood from the above description and from
the accompanying drawings, the present invention provides a hammer
drill bit chuck attachment that is inexpensive to manufacture, that
- 29 -
CA 02555533 2006-08-08
is robust, wherein the frequency and amplitude of impacts can be
adjusted or selected, wherein heat build up is minimized, and
wherein an electric drill used in conjunction with the hammer drill
bit chuck attachment can be operated at lower rotational speeds,
all of which features are unknown in the prior art.
[00079] Qther variations of the above principles will be apparent
to those who are knowledgeable in the field of the invention, and
such variations are considered to be within the scope of the
present invention. Further, other modifications and alterations
.. ..
may be used in the design and manufacture of the hammer drill bit
and hammer drill bit chuck attachment of the present invention
without departing from the spirit and scope of the accompanying
claims.
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