Note: Descriptions are shown in the official language in which they were submitted.
The invention relates to keys for drill chucks and has for its
object to provide an improvement therein.
According to the invention, there is provided a key for a drill
chuck, the key including a geared head component and a handle component the
latter being of machined, forged, cast or moulded form. The geared head com-
ponent is formed with a shank having an end portion adapted to provide an
effective anchor within the handle component. The handle is rotatably mount-
ed on the shank and is provided with an overload release mechanism for limit-
ing the amount of torque which can be applied to the geared head component.
The overload release mechansim may conveniently be constituted by
one or more spring elements housed within the handle and bearing against a
flat surface, or respective flat surfaces as the case may be, formed on the
shank. Such an overload release mechansim will preferably be such that the
maximum applied torque when the chuck is being tightened will be lower than
that when the chuck is being slackened. A lugged collar may be provided on
the shank for free rotation on the shank and for the attachment of a leash by
means of which the key can be permanently connected to a power drill or like
tool.
The geared head component may be formed integrally with the pilot
portion and with the shank portion. However, on the other hand the geared
head component may be formed with a cylindrical bore through which extends a
cylindrical portion formed, cast or moulded integrally with the handle, a
projecting spigot part of said cylindrical portion forming
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the pilot portion of the key. Alternatively, the geared head component may
be of composite construction, being fo~med of a geared head element and a
separate shank, the two having been subsequently joined together, for example
by friction welding, by pressing or by the use of a suitable adhesive. Such
a geared head element may be formed for example by forging or by the use of
sintered metal techniques and may be formed integrally with the pilot portion
of the key and with a spigot portion adapted to be received in a socket por-
tion of the shank.
In order that the invention may be fully understood and readily
carried into effect, the same will now be describedg by way of example only~
with reference to the accompanying drawings, of which:-
Figure 1 is a sectional side view of one form of a drill chuck key~
Figure 2 is a plan view thereof,
Figures 3 to 7 are views similar to Figure 1 which illustrate pos-
sible modifications which will presently be referred to, and
~igures 8 to 28 are further views which will be referred to when
describing other forms of chuck keys.
~eferring now to Figures 1 and 2~ the chuck key there illustrated
includes a geared head component 10 (which has been formed with an integral
pilot portion 12 and shank 14) and a handle component 16. In this particular
embodiment the component 10 has been made by forging (but could have been
machined from bar) and the handle component has been moulded in a synthetic
plastics material around a splined outer end portion 18 of the shank 14. A
small hole 20 has been moulded in the handle for hanging up of the
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key against loss or for the addition of a loop or for
the attachmen-t of a leash (no-t shown) by means of which
the chuck key can be permanently connected to a drill the
chuck of which i~ is -to operate (or connected to the
electric cable of a portable power tool)~
The chuck key just described is of an attractive
appearance and it has been found tha-t the shape of its
handle is such that it afford3a comfortable grip and
facilitates the application of the required tightening
~0 torque to the geared head component~ However, various
minor modifications can be made to this form of chuck
keyO For example, in Fig. 3 the splined portion 18 of
the shank 14 is shown to extend over a longer distance
and the handle is shown to be provided with a skirt 22
which e~tends to the geared head. On the other hand, in
Fig. 4 the splined portion 18 is shown to-have been
formed on the shank 14 adjacent the geared head and the
handle component 16 is shown -to have been formed with
cavities 24 in its undersideO
It will of course be understood that the chuck
keys so far described could all have been made by moulding
the handle as a component separate from the geared head
component and then joining -the two components together by
forcing the shank 14 into the cylindrical cavity moulded
in the handle, with or without the use of an adhesive. In
fact, the construction of key illustrated in Fig. ~ is
especially adapted to this method of mamlfacture since it
can be arranged for the plain outer part of the shank to
be entered easily into the cylindrical cavity moulded in
the handle to act as a guide member before the splined
portion 18 is force fitted in said cavityO
Referring now to ~igo 5, in a further modification
of the chuck key described with reference to ~i~s 1 and
2, the plain portion of the shank 14 between -the geared
head and the synthetic plastics handle is shown to be
loosely encircled by a lugged collar 26 to which is connect-
ed a flexible leash 28 by means of which the key is shown
-to be connected to the electric cable of a portable power
tool (although of course it could equally well be
connected to a part of the power tool or other suitable
anchor point instead of to the electric cable). In Fig.
5a the leash illustrated is shown to be provided at each
end with a notched head portion 27 which can be inserted
through any one of a number of a~jacent slots 29 to form
a closed loop (or of course the notched head could be
inserted through an eyelet or lug such as that of the
collar 26) but it will be understood that any other form
of leash may be employed if preferredO ~he collar 26 is
of solid form as shown in end view in Figo 6 so that of
course it has been requirea to be threaded onto the shank
14 of the geared head component 10 before the latter has
been united with the separately moulded handle component
16~ However, in Figo 7 there is shown in end view an
alternative collar 26 which is of split form so that it
can be sprung over or around the shant~ 14 and of course
-this can then be fitted -to a key which has been formed
in the manner of the key originally described with
reference to Figso 1 and 2 or to a key the geared head
and handle components of which have already been united
together (Such a collar 26 of split form could loosely
surround the skirt portion 22 adjacent to the gcared head
in the construction sholm in Figs~ 3 and 4~ In this way
the kcy would bc a~b to rotate freely l~ithin the collar,
thus preventing the leash becoming tangled as the chuck is tightened or un-
tightened by the key).
Referring now to Figure 8~ this illustrates a chuck key very similar
to those previously described except that the geared head component 10 has
been formed with a shank 14 which terminates in a winged or flatted root por-
tion 30. (The handle 16 in this case will have been moulded around the root
portion).
Referring now to Figure 9, in another form of chuck key7 the handle
component is of winged head form as shown and the shank 14 of the geared head
component is shown to terminate in a crimped root portion 32 around which the
handle component has been moulded. (However, it will be understood that this
winged head form of handle could be fitted to any of the chuck keys previously
described in which case the winged head could be of forged, stamped~ cast or
sintered metal construction).
In Figures 10, 11, 12 and 13 there is illustrated still a further
form of chuck key. In this case it will be seen that the geared head compon-
ent constitutes little more than the geared head and is formed with a cylindri-
cal bore 34 ~or receiving a spigot portion 36 which has been moulded or cast
integrally with the handle 16. ~owever, the geared head is formed with a
lipped annular projection 38 which is received in a depression of complemen-
tary shape in the handle part and it will be seen in Figure 12 that the gear-
ed head is in addition formed with oppositely disposed key pieces 40 which
merge with the projection 38 and engage complementary slots in the handle
part so that a driving connection is established between the two.
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f~
The geared head component in this case may have
been formed for example by machining or by ~orging or by
sintered metal technology or by moulding o.r castingO ~he
geared head component may havc been placed in the mould
prior to the moulding or easting of the handle partO On
the other hand thc han~le part may have bcen moulded, cast
or sin-tered prior to the two parts having been snapped
togetherO
Referring now to Figso 14 and 15, the chuek key
there illustrated is very similar to that jus-t described
: but the geared head component 10 eonstitutes no more than
the geared head and the handle part is of a somewhat
different shapeO In addition the spigot portion ~6 is
stepped down slightly from the cylindrical portion which is
a tight fit in the bore 34 of the geared head
In Figo 167 which is an exploded view, a chuek key
whieh is very similar to that jus-t deseribed has its handle
part of a sligh-tly differen-t form and has a geared head
eomponent 10 which is exaetly the same exeept for the faet
that it has a shallow cross slot 35 for the reccption of
eomplementary key pieees 37 formed on the handle partO
~his particular construction lends itself to the idea of
supplying one or more replaeement geared head eomponents
with a ehuek key of -this ~ind so tha-t when the teeth of
the original gcared head component beeome badly worn it
ean be removed from thc eylindrical portion of the
handle part so that a replacement ean be fitted. ~his
operation will of course bc facili-tated if the geared head
component is made only a medium tight press fit on the
~0 eylindrieal porticn so that the removal of a worn
component is no-t rendered too difficulto On the other
hand of course it will bc understood that- other means may
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be employed for fixing a geared head component on the cylindrical portion of
the handle part.
In Fig. 17 there i5 illustrated an alternative form of handle part
which oDuld be employed in the chuck key just described.
In Fig. 18 there is illustrated a chuck key having the same external
appearance as the key illustrated in Figs. 14 and 15 but it will be seen that
the geared head component has been made of a comp~site construction, that is
to say it has a metal shank 14 with an integral pilot portion 12 and a geared
head 10 having a cylindrical bore, the geared head having been press fitted
on said shank. A handle oo~ponent 16 moulded in a synthetic plastics materi-
al or fo med by forging, casting or sintering has keen subsequently press
fitted on the outer end portion of the shank which in this case has been
shown spl med but could be round, square, hexagonal or of mating shape to
the bore in the handle.
Referring now to Figs. 19 and 20, there is illustrated a chuck
key the external appearance of which is almost exactly the same as that of
the key described with reference to Figs. 2 and 3. However, in this case it
will be seen that the handle part is hollow and houses within it means, i.e.
an overlo~d release mechanism, for lImiting the amount of torque which can
be applied to the geared head component. The handle part itself i5 rotatably
mounted on the shank portion of the gear3d head comFonent but is provided
with a recess within which a U-shaped element 40 made of flat steel strip is
housed. The limbs of the element 40 normally lie against opFositely disposed
flat surfaces 42 which are formed on the shank of the geared head camponent
so that they can transmit drive thereto. However, the arrangement is such
that if an e~cessive torque is applied to the handle part the limbs of the
element 40 are deflected, that i5 to say caused to bow outwards away from
each other, so that the handle part is able to turn relative to the geared
head component. (The handle part is shown in Fig. 19 to be rotating freely
on the shank of the geared head component. In Fig. 20 the parts are shown
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in their normal positions, that is to say before an excessive torque has keen
applied). The ovexload relea æ mechanism just referred to is enclosed in the
hollow interior of the handle by means of a cover piece 44.
In Fig~ 21 there is illustrated a m~dification of the chuck key
just described, the modification residing in the fact that the single U-
shaped element of the overload release mechani~m has been replaced by a Fair
of such elenE~lts placed within oppositely tapering parts of the hollow
interior of the handle as shown so that their curved portions normally bear
against the flat surfaces 42.
In a different mDdification shown in Fig. 22 the single U-shaped
element 40 of the overload release mechanism has been replaced by a pair of
substantially L-shaped spring steel elements 46 of slightly crinXled form
and placed as shcwn in the oppositely dis~osed tapering parts of the hollow
interior of the handle. The shaFe of the elements 46 is such that by trial
and exFerImsnt they have keen ~ound to bear with the required torque trans-
mitting pressures against the flat surfaces formed on the shank so that the
handle can transmit the required maximum tightening torque to a drill chuck
for efficient use without da~age to the chuck and key gearing and related
component parts. The self-locking action of the spring steel elements 46
when the key handle is reversed ens~res that the chuck grip can be relea~ed
kecause the arrangemen~ is such that the applied torque transmitted when the
chuck is keing ti~htened is lower than when it is keing slackened.
The various constructions so far described and illustrated (with
the exception of tho æ illustrated in Figs. 10 to 18) have been described as
having a geared head component formed with an integral pilot portion 12 and
shank 14. ~Iowever, the geared head component could ke formed sep æ ately
frcm the shank 14 andVor the pilot portion 12 in several ways.
For ex~m~le, Fig. 23 is an ex~loded view of a geared head component
of composite construction having a geared head element generally indicated
48 (with an integral pilot portion 12 at one end and with a cylindrical
socket portion 50 at the other) which has been made either by forging or
by sintered metal technology or by machining or casting, and a separate
cylindrical shank 14 with a knurled or splined portion 18 at one end, the
shank having been formed from steel rod. The tw~ components mav be joined
together with the shank located in the socket portion of the geared head
elemPnt, in any of a num~er of ways, for exa~ple by a friction welding
technique or by the application of an adhesive such as 'ILoctite'' (Registered
Trade Mark). It will be understood that such a co~lposite construction of
geared head component may be used in any of the previously describad forms
of chuck key (with the excepti~n of those described with refexence to
Figs. 10 to 18 of course). It will also be understood that instead of being
provided with a splined or knurled portion for the subseguent connection of
the handle part the separate shank 14 in Fig. 23 could be for~ed integrally
with a handle part as a projecting spigot portion for reception in the
soc~et portion 50 of the geared head. Alternatively, instead of being formed
with a cylindrical socket portion the gearecl head ele~ent could be formed
with a sochet portion of square, hexagonal or any such relatecl form for the
xeception of one end of a driving elemant constituted by a short length of
square, hexagonal or such related form of bar the other end of which is to be
received in a similar socket portion of the handle part. Such a construction
is shown in Fig. 24 where a geared head element 48 if formed with a sccket
portion 50 of square form, a driving element 56 is constitutecl by a short
length of square bar, and a handle part is formed with a socket portion 58
of square ~brm. me component parts will in this case be joined together by
the application of a suitable adhesive or by the elements being of a press
fit. (Obviously of course any other of the various shapes of handles pre-
viously illustrated could have been used in this instance, m~dified b~ the
addition of the square shaped socket).
In Fig. 25 there is illustrated another form of composite con-
struction of geared head component. In this case the geared head element 48
-- 10 --
has been formed wi,th an integral pilot portion 12 and wi~h an integral spigot
portion 52. The shank 14, which has aga,in been formed from steel rod, is
formed with a socket portion 54 at one end for the reception of the spigot
portion 52 and as in the previous example the two components may be joined
together in any one of a number of ways~ (Here again it will be understood
that the socketed shank part could be formed integrally with the handle part,
for example as shown in Figure 26. Alternatively~ the socketed shank part
may be a drawn down component as shswn in Figure 27. Such a drawn down form
of shank may be used in an integral geared head and shank construction as
shown in Figure 28 and arranged to fit many of the handle forms previously
described or arranged to form its own integral handle).
~.y
