Note: Descriptions are shown in the official language in which they were submitted.
2~7137~
-- 1 --
IMPROV~MENTS IN C~N_OPENERS
This invention relates to can openers. In
particular the invention relates to a can opener of the
type which will r~move the lid of a can by making a cut
through the outer part of the join between the lid and the
wall of the can.
Examples of such can openers are shown in United
States Patent No 4734986 and Specification No WO90/05108 to
which reference is directed. The can openers shown make a
thin cut around the rim throu~h the material of the lid
itself where it is folded over and arou~d the top of the
upright w~ll of the can. The lid is then removed from the
rest of the can by means of a gripping mechanism which
levers the lid from the remainder of the can.
Such can openers have a number of advantages over
exist mg can openers in that the remaining top edge of the
opened can is not sharp. Thus what is in fact exposed is
the turned over top edge of the side wall of the can and
that is smooth and so unlikely to cut a user who may hold
it or touch ito Also the top edge is still well rein~orced
by the remaining folded-over material of the can and~ 60 r
when the can is gripped, it still retains it's shape.
Further, since the cut takes place only on the outside of
the can wall and there is no penetration through into the
interior o~ the can, no metal filings or the like will
~0713~
contaminate the contents of the can and the possibly
unhy~enic cutting knife does not contact the contents of
the can.
A problem we have found with such can openers is
that the e~fort involved in driving the can opener around
the rim is ~uite high. Generally the users of such can
openers are housewives and ofte.n therefore they find the
effort involved is hard and this can make the can openers
unattractive from this point of view.
10It is an object of the invention therefore to
provide an improved can opener where the effort of driving
the can opener around the rim can be kept within reasonable
limits.
According to the invention ther~ is provided a
can opener for openi~g a can having a lid ~oined to a main
body by a rim, in which the can is opened by cutting
through an outer part of ~he rim joining the lid with the
: main bod~ of the can, the can opener comprising a rotatably
supported cutter wheel for engaging and cutt ng the said
~0 outer part of the rLm, a rotatable drive wheel for engaglng
the inner part of the r~m, means for gripping the rim
between the cutter wheel and drive wheel so that, upo~
rotation of the drive wheel, the can opener orbits around
the rim of the can and the cutter wheel can complete a cut
around the outer part of the rim, and lever means driving a
one-way clutch mechanism for rotating the drive wheel to
advance the C~l opener around the ca~.
2~7137~
We have found that with such a can opener one
can, by applying a relatively mGdest force to the lever
; means, progressively advance the cutter wheel. The lever
means will be reciprocated so that during each movement in
a the forward direction the cutt:er wheel will be turned by
a relatively small amount to advance the can opener and
during each movement in a return dixection the one-way
clutch mechanism will allow the return of the lever means
without at the same time driving the cutter wheel in the
reverse direction.
Preferably the means for gripping the rim between
the cutter wheel and drive wheel include a pair of pivoted
body members which have arms extending away from the point
of pivoting. Then as the arms are brought together this
will move the cutter wheel and drive wheel towards one
another so as to grip the rLm. Egually when the anms are
moved apart then the cutter wheel and drive wheel are
themselves moved apart so as to release the grip.
In a preferred ~mbodiment of the inventio~ the
lever mean^c comprise a third arm or lever which is pivoted
about the axis of rotation of the drive wheel and which can
be moved between closed and open positions, with the one-
way clutch mechanism free wheeling and so not rotating the
drive wheel as it is moved towards its open position and
the clutch mechanism rotating the drive wheel as it is
moved towards its closed position adjacent one of the arms
of the body members.
3 ~ ~
~,
Preferably the lever arm is resiliently urged
towards its open position by spring means so as to present
itself in a position ready for rotating the drive wheel.
Also it is in a preferred embodiment, locking means are
provided to lock the lever arm in its closed position
adjacent to one of the said arms of the body members. T~us
when the arms of the body members are opened and closed to
cause the gripping or release of the rim of a can, the
lever arm lie~ flush with the said one ar~ and is moved
with it. This ensures that the lever arm does not ma~e the
overall can opener cumbersome to handle and use~
A simple one-way clutch mechanism inclu~es a
resiliently mounted ratchet driven by the lever means which
engages with teeth formed on or attached to a spindle for
the drive wheel, the ratchet engaging and locking with the
teeth in one direction o relative rotation and free
wheeling and sliding over the teeth in the reverse
; direction.
To further red~ce the effort of rotating the
drive wheel, it is preferred that the dxive wheel be
supported by a metal shaft which is rotat~bly journaled
within a metal sleeve supported by the body of the can
opener, the outer surface of the sh~ft and the inner
surface of the sleeve mating at positio~s adjacent the ends
of the sleeve so as to provide rotational support for the
shaft and intermedia~e those positions a gap being provided
between the outer sur~ace of the shaft and ~he inner
~7~37~
surface of the sleeve to avoid contact between the shaft
and sleeve so as to reduce frictional forces upon rotation
of the shaft relative the sleeve.
With such an arrangement the ~rictional ~orces
between the two parts of the metal shaft which engage the
sleeve and the sleeve itself are kept quite small and
unnecessary frictional forces are avoided by providing the
gap between ~he central portion of the shaft and the
sleeve. Thus, it is not necessary for that central portion
to contact the sleeve to provide good rotational support
provided the ends of the sleeve mate with the shaft. In
addition, the resulting recess can be filled with a
lubricant such as a grease to reduce frictional contact in
the mating regions.
The interior surface of the sleeve and external
surface of the shaft are preferably of hardened steel so a~
to ensure that frictional forces are kept to a minimum.
For ex~mpIe, they should both be hardened and tempered to a
specification according to Rockwell Hardness C scale ~HRC)
within the range o~ 45 ~o 56.
: Accordiny to one sLmple e~bodimen~ of this aspect
of the invention, the sleeve is of constant internal
cross-sectional diameter whilst the shaft has a region of
reduced diameter between the areas of intended contact with
the sleeve so as to provide the said gap.
As explained in Specification No WO90/05108 it is
desirable that the cutter wheel makes its cut at a
2~7~
substantially constant predetermined distance up the rim
from its lower end. As explained in that Specification
this can be achieved hy providing resilient means for
allowing the cutter wheel to move resiliently in an axial
direction along its axis of rotation, and cam means joined
to the cutter wheel and axially spaced from the cutter
wheel by a predetermined amo~nt, the cam means being
arranged to engage the underside of the rim, the engagement
underneath the rim moving the cam means and the cut~er
wheel against the resillent means to a posi~ion such that
the cutter wheel makes its cut at a substantially constant
predetermined distance up the rim from its lower end.
In this way a consistent good result can be
achieved since, irrespective of the shape and size of the
can or of the size and depth of the rim, a cut can be
achieved in the best position for lid removal since the cam
means will engage under t~e rim and if necessary move the
cutter wheel against the resilient means to a set position
above the lower edge of the rim. Further, if there is any
variation i~ the rim depth as the opener orbits around the
can, this will also be ac~ommodated.
In one prefexred embodLment the cam means
comprise a circular flange having an upper face which is
slightly inclined relative a plane radial to the axis of
the flange and is arranged to engage under the rim, the
inclined upper face movi~g the circular flange and the
associated cutl:er wheel agai~st the resilient means as the
2~37~
-- 7 --
flange is forced in beneath the rim when the rim is gripped
between the cutter wheel and drive wheel and the cutting
edge of the cutter wheel is forced to penetrate through the
outer part of the rLm. The circular flange has a larger
diam~ter than the cutter wheel since it engages the upright
wall of the main body of the can which is of necessity of
smaller diameter than the rim. The difference in diameters
can, however, be chosen to ensure that the cutting edge of
the cutter wheel does not penetrate significantly beyond
the material of the outer part o~ the rim.
The circular flange and cutter wheel can be
formed from a single piece of material or could be made
separately and then joined so that they will rotate
together and move tog~ther longitudinally of their
rotational axis. Conveniently, they are jointly mounted
about a common axle on wbich they rotate.
The resilient means can comprise a resilient
rubber washer mounted between the cam means and a
stationary support. Thus, as the cam means move the cutter
wheel down to ~it the cam means beneath a rLm, that washer
will be compressed, and when a cutting operation is over
then the compressed w~sher will restore the cutter ~heel to
its rest position along its rotational axis.
As e.xplained in the above noted United States
Paten~, thexe are problems in providing the necessary close
tolerances in the suppoxt of the cutti~g knife of the can
opener and the Patent aims to provide one way of achieving
207~37~
this. As described in the above noted Specification No
WO90/05108, however, it is preferred that the cutter wheel
be rotatably supported on a shaft upstanding from one of
the body membexs, a circular flange of diameter greater
than the cutter wheel being provided on the said shaft, and
an arcuate support wall upfitanding from one body member be
provided centered on the axis of rotation of the cutt~r
wheel, the circular flange being arranged to ~ear against
the support wall to assist in supporting the sha~t and
cutter wheel during cu~ting of the rim of a can.
We have also found that with such an arrangement
the rotational axis of the cutter wheel can be maintained
accurately even under high cutting loads. Generally the
body members will be made of synthetic plastics material
and so the axis of the shaft, which may ~e integrally
formed with the said one body member or may be a separately
member, will be liable to distort under load because the
plastics material of the said body member will be incapable
of resisting this distor~ion~ It is undesîrable for this to
occur since then the required close cutting tolerances will
be lost, bllt this distortion is kept to a minimal level by
the support given to the shaf t . Thus, the arcuate supp~rt
wall buttresses the circular flange mounted on the shaft
and so helps to prevent bending of the shaft under
load, particularly if the circular flange is mounted
outwardly of the cutting edge.
~7~37l.~
g
We have found that it is of importance that there be
close tolerances in the positioning of the cutting knife on
a can to ~e opened. Therefore, it is preferred that one of
the pair of body members pivotecl to one another and having
integral handles extending generally in a direction away
from the axis of pivoting, have a substantially flat
surface in the region of the nip between the cutter wheel
and the drive wheel, and that the integral handle of the
other body member have an undersurface which is
substantially flat and also substantially in the same pla~e
as the s~bstantially flat surface on the said one body
member, whereb~ when the body members and their integral
handles are pivoted to allow the can opener to be fitted
over the rim of a can, those two surfaces will rest on the
top of the rim of a can and will align the axis of the
cutter wheel so that at least in the plane containing them
it is parallel with the upright axis to the can.
This has the advantage that the circular cutting
edge on the cutting wheel will be accurately aligned in the
direction of the cut to be made and ensures ~hat, as the
body membQrs and their handles are pivoted together to
bring the drive wheel and cutter wheel close together to
grip the rim, the initial penetration of the rim by the
: cutting edge will be accurately aligned in the desired
directio~ of the cut to be madec As a result an improved
consistency of cutti~g from one ca~ to another can be
achieved~
2~7~37~
It is preferred that the said one body member
which supports the cutter wheel also have a further contact
surface on the opposite side of the drive wheel from the
cutter wheel. This contact surface should be spaced
downwardly from the said substantially flat surface on the
said one body member by an amount substantially equal to
the inner depth of the rim, that is to say the height of
the rim above the central top reS1ion of the lid. Thus, this
further contact surface will rest on the top of the lid and
ensure that the ax.is to the cutter wheel is also aligned so
as to be parallel with the upright axis of the can in a
direction transverse to a plane cuntaining them. In effect
with this additional contact surface there is a three point
contact with the can when the body members are pivoted to
their open position and the can opener plac~d over the rim
of a can to opened which guides the user so that, as the
handles are closed, the cutter wheel is kept in correct
alignment to penetrate the rLmO
As described in the ahove noted Specification No
WO90~05108 it is preferred that the drive wheel has a~
outer cylindrical surf ace which is serrated to allow it to
grip into the material o~ the rim to assist in driving the
can ope~er around the can, and the lower edge, that is to
say the edge adjacent to the lid of the can when in use, of
the outer cylindrical surface of the drive wheel is
bevelled.
2~713'~
By providing this bevel we have surprisingly
found that a more reliable drive action is achieved even
through the effect of the bevel is actually to reduce the
area of contact between the drive wheel and the rim of the
can. In particular it seems that in tight corners of a can,
the rLm is often distorted and not upright so that with a
drive wheel having a completely cylindrical outer ~ace only
a line contact is achieved anyhow whereas with a can opener
according to this aspect of the inv~ntion a much larger
area of contact can be achieved between the drive wheel and
the rim of the can in tight radius corners.
Additionally we have found that it is desirable
to keep the tolerances of the depth of the cut made very
close to the desired amount so that the c-ltter wheel does
not penetrate into the rim significantly further than the
outer layer of material. Further the gripping force between
the cutter wheel and drive wheel should desirably not
distort the rim of the can. The bevel also has the
advantage o ensuring that the outer peripheral surface of
the drive wheel can fit closely to the inner face of the
rLm without significantly distorting the rim.
The angle of the bevel is preferably about 45
but could, for example~ range from 30 to 60 to the axis of
the drive wheel. Preerab1y also the bevel exte~ds radially
inwardly at the lower edge of the drive wheel by an amount
at least equal to the depth of the serrations.
2~713~
- 12 -
We have also found that it is desirable that the
serrations in the drive wheel be relatively shallow since
if the serrations are too large they are liable to bite
into the rim of the can and damage it and lock the layers
of the rim together, with the result that it may not be
easy to lever off the severed lid. Preferably therefore the
maximum radial depth of the teet:h or serrations is no more
than 1.5 mm and most preferably the radial depth is no more
than 1 mm. Generally speaking thexefore there will be a
relatively large number of shallow, closely spaced
serrations.
After the cut ha~ been made, the severed lid has
to be removed from the rest of the can. According to
another aspect of the invention this can opener has o~ one
side thereof a point resiliently urged towards a fixed
abutment, the point being capable of entering the cut an~
so lifting one side of the lid from the can when the body
of the can opener is used to lever off the lid. The point
is provided on a pivotally mounted mlember which is
resiliently mounted to urge the point towards the abutment,
and an arm is provided which can be manually moved against
the resilient force, to open up a gap between the point and
the abutment to allow them to be initially fitted over the
rim of a can.
An example of a can opener according to the
invention will now be illustrated, with reference to the
accompanying clrawings, in which:
20 ~1374
- 13 -
Figure 1 is a side elevation of the can opener;
Figure 2 is an underneath view;
Figure 3 is a plan view;
Figure 4 is an elevation from the other side;
Figure 5 is an enlarged cross-sectional detail taken
along the line 5-5 of Figure 2;
Figure fi is a side view showing the can opener in use
on the firs~ step of opening a can;
Figure 7 is an enlarged detail of the are~ circled in
Figure 6 and marked 7 in th~ case of one can;
Figure 8 is an enlarged detail similar to Figure 7 but
showin~ the case of a different can;
Fiyure ~ is an enlarged sectional detail taken along
the line 9-9 of Figure 4;
Figure lQ lS an underneath view showing the can opener
; in the open d posi~ion;
; Figure 11 is a pla~ view of the can opener showing the
lever arm in its opened p~sition;
Figure 12: is an enlarged cross-sectional detail
: 20 showing the second step in the removal of the can lid;
and
Flgure 13 is an enlarged sectional detail taken along
the line 13-13 of Figure 1.
The can opener 10 shown in the drawings comprises
a pair of handles 12 and 14 ~hich are integrally formed
with body portions 8 and 6, respectively. The latter are
pivoted to one another about a spigot 20 (Figure 5) which
~7~37~
is integral with the body portion 16 and which extends into
a corresponding opening 22 in the body portion 18.
A spindle 24 passes through the spigot 20, the
spindle being farmed at one side with a drive wheel 26.
This has on its outer f aae, serrations, or teeth 27 to
allow it to grip the inside of a can rim 29 so that, when
it is rotated, it will drive the can opener 10 around a can
30 to be opened. The lower edge, that is to say the edge
which is adjacent to the lid of the can when in use, of the
drive wheel 26 has a chamfer or bevel 26a. This chamfer or
bevel ~6a is at an anyle of a~out 45 and extends to a
depth slightly greater than the serrations or teeth 27.
At its other side, the spindle 24 is joined to a
ratchet gear 31 which is driven by a ratchet 32 în turn
operated by the movement of a lever arm 33 as will be
described.
The drive spindle 24 is rotatably journaled in a
steel sleeve 28 embedded within the material of the spigot
20. At spaced regions 2~a and 28b ad~acent the ends of the
2~ ~leeve 28, the spindle 24 has a diameter such that the
spindle is a good mating ~it within the sleeve. In this
way good rotational support is provided for the spindle.
In a central region 28c, however, the spindle is of reduced
diameter so as to leave a gap 28d between the spindle 24
and sleeYe 28. This gap could be of a radial distance of
around 0.4mm~ Because there is therefore no contact
2~7~.~7~
- 15 -
between the spindle and sleeve in this central region,
there is therefore no friction created from the region
during rotation of the shaft. Also a lubricating grease
can be provided within the gap 28d for lubrication of the
s7iding surface~ in the reyions 28a and 28b. In these
latter regions, however, there is a good mating fit between
the interior of the sleeve a~d the exterior of the sha~t so
that good rotational support is given. Desirably the
interior surface of the sleeve and exterior surface of the
shaft have been hardened and tempered to HRC of 56 to
reduce frictional forces.
As best seen in Figure 5, the axis 34 of the
spindle 24 is offset from the ~xis 36 of the spigot 20. In
this way, when the handles 12 and 14 are opened up to the
position shown in Figure 10 by pivoting the portions 16 and
18 about the spigot 20, the drive wheel 26 is moved away
from a cutter wheel 4g and so can be placed over the rim 29
of a can to be opened, and conversely, when the handles are
brought togethex as shown i~ Figure 2 and grasped in the
hand of a user, the drive wheel 26 is moved in closer to
the cutter wheel 40 so that the rim 29 of the can is
gripped between the two.
Pivotally mounted about the spindle 24 and held
in place by a head 24a on the spindle 24 is the lever axm
33. In the position shown in Figure 3 this lies flush and
is approximately aligned with the arm 14. In that
connection the arm 14 has a longitudinally extending recess
2~ 37~
14a (Figure 11) in which the arm 33 nestles and is a close
fit.
The arm 33 is urged away from the arm 14 by means
of a spring (not show~) whose ends act between the léver
arm 33 and the bady portion ;L6. The lever arm 33 can
however be restrained in the position shown in Fi~ure 3 by
means o~ a locking loop 34 pivotally joined to the e~d o~
the arm 14. The loop 34 therefore holds the handle 14 and
arms 33 together in this position so that they move as one.
When the loop 34 is unhooked from the arm 14, however, the
arm 33 can spring out to an open position shown more
clearly in Figure 11.
As described above joined to the Pnd of the
spindle 24 by means of a key way 31a is a ratchet gear 31.
This is engaged by means of a ratchet 32 resiliently
mounted a recess 33a in the arm 33~ The ratchet has an end
32a engaging with teeth 31b on the ratchet gear and a
spring 35 urges the ra~chet 32 so tha~ its end 32a is
normally in engagement with the teeth 31b. Therefore when
the arm 33 is released from the arm 14 by freeing the loop
34 and the arm is the~ oscillated between the open position
shown in the Figure 11 and the closed position shown in
Figure 3, the ratchet 32 will engage the teeth and so dxive
the spindle 24 and therefore the drive wheel 26 into
rotation as the lever arm is moved fxom the open positio~
whilst the ratchet will slide over the teeth on the ra~chet
~ 0 7 .~
-- 17 --
gear and so not rotate the drive wheel 26 when the arm is
moved to the open position.
The degree of opening of the arm to drive the
wheel 26 can be selected to suit the user. The user may
for example grip the can opener in one hand only and simply
move the lever arm by a small amount as shown for ex~mple
by the arrow 36 in Figure 11. Alternatively he may use two
hands, with one hand holding the handles 14 and 16 and the
other moving the lever arm 33 to ~he ullest extent
possible such as for example the 180 movement as shown by
means of the ~rrow 37 in Figure 11.
Integrally formed with the bQdy portion 18 is
an upstanding shaft 44 ~Figure 8) on which the cutter wheel
is idly and rotatably mounted. The cutter wheel
comprises a circular cutting edge 46 and an inte~ral
circular flange 4B. Th~ outer cylindrical face 49 of this
is of slightly larger diameter than the cutting edge 46 so
that the face 49 can bear against an upright side wall 50
of the can 30. The flange also has a slightly inclined cam
edge 51 formed on its upper face which is designed to
engage below the rim 29 of a can. This edge 51 is angled at
about 80 to the axis of rotation of the cutter wheel. It
could however be angled say from 75 to 85 to the axis of
rotation. It is, however important that the edge 51
penetrate under the rim 29 which will normally be 1 to
1.5 mm larger in diameter than the side wall 50 and move
the cutter wheel 40 if reguired as exælained below~
2~3~
The cutter wheel 40 is held in place on the sha~t
44 by an end cap 52 riveted or screwed to the shaft 44
However, between the end cap 52 and the wheel 40 is a
resilient washer 54 of elastomeric material, and in t~rn
between the washer 54 and the wheel 40 is a thin metal
washer 55.
Re~erring to Figures 7 and 8, these show in
detail the construction of the rim 29 of a can 30. The top
of the side wall 50 of a can is bent over in the shape of a
"U" whilst the edge of a lid 62 is bent up around the
inside of the side wall, over the top of the bent-over side
wall, down around the outside of that bent-over portion in
a region 63 and finally its end is bent up inside and so
trapped by the bent-over top of the side wall. It i5 the
bent-over portion of the lid 62 in the region 63 which is
cut ~y the cutting edge 46.
The surface 64 of the body portion 18 between the
cutter wheel 40 and drive wheel 26 is flat and transverse
to the axis of the rotatio~ of the two wheels. In additio~
and as best seen i~ Figures 1 and 4 the undersurface 65 of
the handle 14 is in the same plane as that surface 64.
Therefore when the body portions and their respective
ha~dles are pivoted open to enable a can rLm 29 to enter
between the drive wheel 26 and cutter wheel 40, the top of
the rim 29 can rest on the surface 64. Because this is flat
right across the width of the body portion 16 the resting
of the surface on the rim will align the axis 45 with the
2~7:~3~
-- 19 --
upright axis of the can. In addition with the handles 12
and 14 opened up as in Figure 10 or even further than that,
the surface 65 can additionally rest on the rim 29 (shown
diagrammatically by the broken line 29 in Figure 10) and
assist in ensuring this alignment.
At the outer end of the body member as formed an
integral downwardly extending lug 76 having a lower flat
contact surface 78~ This extends downwardly by an amount
approximately e~ual to the height of the rim 28 above the
top surface of the lid 62. In this way, by resting the
contact surface 76 on the lid 62 when the can opener is
placed over the rim 29 of a can to be opened, one can
ensure that the axis 45 of rotation of the cuttex wheel 40
is accurately parallel to the upright axis of the can.
15 - In the removal of the lid 62, the handles 12 and
14 are first of all opened up by pivoting them apart in the
direction of the arrows 70 (Figure 2) to the position shown
in Figure 10. The arm 33 is restrained by the loop 34 and
moves with the arm 14. This opens up a gap between the
drive wheel Z6 and the cutter wheel 40 as has been
described. The can opener can then be placed over the top
of a can 30 with the rim 29 between the wheels 26 and 40.
The handles are then brought to their closed position as
shown in Figure 2. This causes the rim 29 to be gripped
between the wheel6 26 and 40 and the teeth or serrations 27
of the dxive wheel engage tightly with the inside of the
2~7~3~
- 20 -
rim 29. At the same time, the cutting edge 46 is forced
through the ma~erial of the lid in the region 63.
As has been explained above the surface 64 and 65
ensure that the cutting edge 46 is accurately aligned in
the direction around tha rim 29 in which the circular cut
is to ~e made. Also, the contact of the contact surface 78
with the top of the lid 62 ensures that the cutting edge 46
enters the material of the lid precisely in a direction at
right angles to the upright side wall 60 of a can.
Next the driYe wheel 26 is rotated to orbit the
can opener around the can and make a complete circular cut
through the material of the lid in the region 63. This is
achieved by unhooking the loop 34 from the lever arm 33 and
allowing the arm to open as shown in Figure 11. Then the
arm is repeatedly moved from its open position as shown in
Figure 11 to the closed positisn shown in Figure 3. As
explained above, a~ the arm moves towards its closed
position, the drive wheel 26 will rotate whilst the arm is
allowed to spring outwardly u~der the effect of the spring,
it does not cause the drive wheel to turn in the reverse
direction.
In addition it will be seen best from Fig~re 5
that, when the ha~dles are fully closed, the edge 51 of the
flange 48 has engaged under the lower edge of the rLm 29,
the cyllndrical outer face 49 of the flange 48 contacting
the outer face of the side wall 50 of the can. The depth d
of a rim 29 varies widely from c~ to can and may even vary
2~7~3~l~
-- 21 --
around an individual can. This can lead to inconsistent
cutting and so as to avoid this it will be seen that, if
the depth d is greater than the minimum envisaged in Figure
7, i.e. the situAtion in Figure 8, then the cam surface 51
still engages under the lower edge of the rim 29 but draws
the cutter wheel 40 downwardly, so compress.ing the washer
54. The spacing a between the cutting edge 46 and the
lower edge of the rim 29 remains constant and is of course
fixed by the relative positions of the flange 48 and
cutting edge 46. Consistent cutting results can therefore
be achieved.
Once a complete circular cut has been made, the
arm 33 is brought to its closed position as shown in Fi~ure
3 and held there by the loop 34. Then the handles 12 and
14 are opened up and the can released. At the same tLme,
the washer 54 will restore the cuttex wheel 40 to its
position shown in ~igure 7 if it was moved away from this
in the sense shown in Figure 8.
Integrally ~ormed wi~h the body member 18 is an
upstanding arcuate wall 66. Its axis is centered on the
axis of the shaft 44, and it extends angularly for
approximately 180, half and half on either side of a line
A (see Figure 2~ which is an extension of a line joini~g
the axes of the cutter wheel 40 and drive wheel 26 when the
can opener is in the position shown in Figure 2. The wall
66 could extend angularly for more or less, e.g. fxom about
45 to about 220r half and half on either side of the line
2~7~
-- 22 --
A. In practice if it extends for more than 180 thi~ can
lead to difficulties in assembling the can ope~er whereas
180 is a pre~erred extent so that the wall not only
supports the shaft to prevent bending away in the sense of
a direct line between the a~es of the cutter wheel and
drive wheel but also supports the shaft to prevent sideways
bending as the can opener makes a cut.
As best shown in Figures 7 and 8, the inside ~ace
68 of the w~ll has a diameter a~proxLmately the same as
that of the outer cylindriaal face 49 of the flange 48.
That face 49, therefore, abuts the face 68 and in this way
the wall can buttress the shaft 44 during a cutting
operation, so preventing substantial distortion of the
shaft 44 and consequent misalignment of the cutting edge 46
with the rim 28. This is despite the fact that the body
member 18 and its integral shaft 44 are moulded frQm
synthetic plastics material.
Upon removal of the can opener 10 the lid 62 will
still appear to b~ intact on the c~n. It can be removed ~y
levexing it off using a mechanism 80, which is provided on
one side of the can opener 18.
As best shown in Figure 13; the mechanism 80
includes a stationery abutment member 82 and a resiliently
mounted gripping member ~4. The abutment member 82 is
fixed to the body portion 18 and includes an upright
abutment wall 86. The member 84 is by contrast mounted so
as to be pivotable about a small upstanding spigot 90
2~7~
-- 23 --
formed in a recess 92 in the body portion 16. It also
includes a lever arm 94 and a forwardly projecting point
96. A spring 98 urges the member 84 so that the point 96
is urged towards the wall 86.
When the mechanism 80 i.s placed over the rim of a
can as shown in Figure 12 the user depresses the arm 94 so
as to open up th~ gap between the~ point 96 and the wall 86.
This is the position shown in full lines in Figure 12. The
upper end of the rim of the can can therefore enter between
the two. The user then releases the arm 94 and so the
spring 98 urges the point 96 towards the wall 86 so that
the point snaps into ~he cut made in the material of the
lid 62 in the region 64. This is the position shown in
broken lines in Figure 12. The resilient force of the
spring 98 urges the point and wall together and ensures
that the point enters and is held in this cut.
Next the handles 12 and 14 of the can opener are
levered upwardly and the point 96, which is engaged beneath
the cut, forces the severea psrtion of the lid off from the
rest of the can to op2n it.
