Can opener

A can opener has a blade-carrying member pivotably connected to a housing and a hooked connection between the blade-carrying member and the housing that permits the blade-carrying member to be disconnected from the pivotal connection when an actuator of the can opener is moved to a release position. The can opener may be provided with a stop to prevent the disconnection and removal of the blade-carrying member unless the actuator is in the release position.

TECHNICAL FIELD OF THE INVENTION
 The present invention relates to can openers and in particular, though not
 exclusively, to can openers for use in catering establishments.
 BACKGROUND OF THE INVENTION
 A typical can opener, shown in FIG. 1, comprises an operating handle 2, a
 housing 4, and a blade 6 carried by a blade carrying member 8, which in
 turn is pivotally connected to the housing 4. A stem or post (not shown)
 extends from the housing 4 into a sleeve 10 connected to a table or work
 surface 12. In use, a can 14 is gripped between the blade 6 and a drive
 wheel (not shown) connected via a spindle to the operating handle 2.
 Rotation of the operating handle 2 causes the can 14 to be rotated against
 the blade 6. The pivotal connection between the member 8 and the housing 4
 is necessary to enable the can 14 to be fitted to, and subsequently
 removed from, the can opener. The pivotal connection is achieved by a pin
 16 fixed in the housing 4 passing through a hole in the member 8.
 It is imperative in a catering establishment that all utensils be kept
 clean so as to prevent the cultivation and transmission of germs and
 bacteria. Can openers of the type described above have been found
 difficult to clean as the member 8 is not intended to be removed from the
 pin 16. Particularly at risk is the blade 6 which comes into direct
 contact with the contents of the opened cans. If the blade 6, and the
 adjacent blade carrying member 8 to which it is attached, are left
 unwashed then both germs and bacteria can accumulate and transfer to the
 contents of other cans.
 U.S. Pat. No. 5,052,110 describes a can opener wherein the fixed pin 16 is
 replaced by a removable pull pin. Removal of the pull pin allows the blade
 carrying member to be removed from the housing to permit cleaning thereof.
 Problems exist with this arrangement whereby loss or breakage of the pull
 pin renders the can opener unusable. In addition, repeated removal and
 refitting of the pull pin can lead to wear of the pin and/or the housing
 with the result that the pin is liable to work loose during the normal
 operation of the can opener. This can affect the operation of the can
 opener and possibly lead to the pull pin and/or blade carrying member
 falling into a can when said can is in the process of being opened.
 SUMMARY OF THE INVENTION
 The present invention thus provides a can opener from which the blade
 carrying member can be removed easily to allow cleaning thereof. Removal
 is effected by moving the actuation means provided for the normal
 operation of the can opener to a release position; this thereby eliminates
 the need to at least partially disassemble the can opener prior to removal
 of the blade carrying member. The need for special tools or skills to
 effect removal of the blade carrying member is also eliminated.
 DETAILED DESCRIPTION OF THE INVENTION
 According to a first aspect of the present invention there is provided a
 can opener operable in use to rotate a container relative to a blade of
 the can opener, the can opener comprising a housing, a blade-carrying
 member releasably connected to the housing and pivotable relative thereto,
 and actuation means for pivoting the blade-carrying member and for
 rotating a container, wherein a hooked connection is provided between the
 blade-carrying member and the housing, the hooked connection being
 separable so as to enable the blade-carrying member to be removed from the
 housing when the actuation means is moved to a release position.
 The hooked connection comprises a hook on one of the housing and blade
 carrying member and a pin or axle of the other of the housing and blade
 carrying member. In a preferred embodiment the blade carrying member is
 provided with a hook and the housing with a pin. In an alternative
 embodiment the blade carrying member may be provided with one or more
 axles and the housing with slots adapted to receive the axle or each of
 the axles.
 Preferably the can opener is provided with stop means to prevent the
 separation of the hooked connection unless the actuation means is in the
 release position. The stop means may comprise a projection on one of the
 housing and blade carrying member and a recess in the other of the housing
 and blade carrying member. In a preferred embodiment the projection and
 recess are provided on the blade carrying member and housing respectively.
 In such an embodiment the projection is preferably positioned opposite the
 open side of the hook. During normal operation of can opener the
 projection is received in the recess and thus prevents movement of the
 blade carrying member relative to the housing in a direction leading to
 separation of the hooked connection. When the actuation means is moved to
 the release position the projection is moved out of the recess and
 separation of the hooked connection is then possible.
 The actuation means may comprise a handle pivotably connected to a spindle
 and having a cam surface at said pivotal connection, a cam follower, a
 spring and a drive wheel. The drive wheel is connected to the spindle and
 is rotatable by the handle. In a preferred embodiment the spindle passes
 through the cam follower and the spring, the spring, in use, being
 provided between a seat in the housing and seat on the cam follower. The
 cam follower may have a substantially hollow centre and an opening into
 which a portion of the blade carrier can project, in use. The spring may
 project into the hollow centre of the cam follower. In such an embodiment,
 the portion of the blade carrying member projecting into the cam follower
 may be shaped so as to fit around the spring. The cam follower may include
 a recess shaped to receive the stopping means projection of the blade
 carrying member.
 The can opener preferably also includes a post extending from the housing,
 said post being slidable in a sleeve attached to a work surface, table or
 the like.
 According to a second aspect of the present invention there is provided a
 can opener operable in use to rotate a container relative to a blade of
 the can opener, the can opener comprising a housing, a blade carrying
 member releasably connected to the housing and pivotable relative thereto
 about a pin or the like fixed to the housing, and actuation means operable
 to pivot said blade carrying member and to rotate a container, wherein the
 blade carrying member is releasable from the housing without removal of
 the pin therefrom.
 According to a third aspect of the present invention there is provided a
 can opener as hereinbefore described with reference to the first or second
 aspect, the actuation means of the can opener having a cam follower
 engageable with the blade carrying member, the cam follower being movable
 by a cam surface of the actuation means to effect pivotal movement of the
 blade carrying member relative to the housing.
 In a preferred embodiment the cam follower is annular. The cam follower may
 be substantially cylindrical.
 According to a fourth aspect of the present invention there is provided a
 can opener operable in use to rotate a container relative to a blade of
 the can opener, the can opener comprising a housing, a blade carrying
 member releasably connected to the housing and pivotable relative thereto,
 and actuation means operable to pivot said blade carrying member and to
 rotate a container, the actuation means including a cam follower
 engageable with the blade carrying member and a spring, the cam follower
 being movable by a cam surface of the actuation means to effect pivotal
 movement of the blade carrying member relative to the housing, and the
 spring being provided between the cam follower and the housing, wherein a
 hooked connection is provided between the blade carrying member and the
 housing, said hooked connection being separable so as to enable the blade
 carrying member to be removed from the housing when the actuation means is
 moved to a release position.

DETAILED DESCRIPTION OF THE DRAWINGS
 A can opener 20 according to an embodiment of the present invention is
 shown in FIGS. 2 to 6. The can opener 20 comprises an operating handle 22,
 a housing 24, a blade 26 and a blade carrying member 28. The operating
 handle 22 has a first end 30 with a rotatable grip button 32, and a second
 end 34 which is pivotally connected to a spindle 36 by a pivot pin 50. The
 second end 34 is provided with a cam surface 48. The spindle 36 is
 supported for rotation about an axis 42 in the housing 24 by a bush 38.
 Attached to the spindle 36 is a drive wheel 40 which protrudes through an
 opening 68 adjacent the blade 26 in a lower portion of the housing 24. It
 will be understood that rotation of the operating handle 22 about the axis
 42 causes rotation of the spindle 36 and drive wheel 40. As described
 above the drive wheel 40 in use moves a can relative to the blade 26. To
 achieve this the drive wheel 40 has an outer edge 44 which is adapted to
 grip the can. Typically this edge 44 is provided with teeth or ribs 41.
 Between the bush 38 and the second end 34 of the operating handle 22 there
 is provided a helical spring 46 and a cam follower 52. The spindle 36
 passes through an aperture 54 in the cam follower 52 and through the
 centre of the helical spring 46. The cam follower 52 is substantially
 D-shaped when viewed from above and has a flat upper surface 56 upon which
 the cam surface 48 of the operating handle 22 acts, in use. A lower
 portion 58 of the cam follower 52 is undercut so as to provide a pair of
 recesses 60 into which portions of the blade carrying member 28 are
 received, in use. The spring 46 is provided between the lower surface 62
 of the cam follower 52 and the bush 38. As shown in FIGS. 3 to 6 the bush
 38 may be provided with a flange 64 which acts as a spring seat or
 alternatively, and as shown in FIG. 2, a recess 66 may be provided in the
 housing 24 above the bush 38 to locate the spring 46.
 The blade carrying member 28 is substantially T-shaped and has a cross
 member 70 with a first end 72 adapted to fit to the recesses 60 of the cam
 follower 52, and a second end 74 adapted to be releasably attachable to
 the housing 24. An arm 76 to which the blade 26 is fixable extends from
 the cross member 70. In the embodiment shown the arm 76 is formed with two
 through holes 78, 80. The blade 26 is attached to the arm 76 by screw type
 fasteners 82 passing through the holes 78, 80 and locating in
 corresponding threaded apertures 84, 86 of the blade 26. The arm 76 may be
 formed with a blade recess 88 into which the blade 26 is received, and
 which serves to align the blade apertures 84, 86 with the arm holes 78,
 80.
 The first end 72 of the cross member 70 is provided with two spaced fingers
 90, 92 which, in use locate in the cam follower recesses 60. At the base
 of each finger 90, 92 there is provided an upstanding stop 94. The second
 end 74 of the cross member 70 is provided with two hooks 96, 98 which, in
 use, enable the blade carrying member 28 to be connected to the housing
 24.
 As can be seen from the accompanying drawings the housing 24 serves to
 accommodate the blade carrying member 28, the spindle 36, the bush 38, the
 wheel 40, the cam follower 52 and the spring 46. The bush 38 fits to a
 correspondingly shaped aperture 100, while the blade carrying member 28,
 cam follower 52 and spring 46 are accommodated in an upper cavity 102. The
 wheel 40 is accommodated in a lower cavity 104. The upper cavity 102 is
 surrounded by a wall 106 and has an opening 108 at one side thereof. The
 housing 24 has a roof 110 with a cut out portion 112 shaped to correspond
 substantially to the plan-view shape of the cam follower 52. The cut out
 portion 112 includes recesses 124 at one side thereof which correspond
 substantially to the cross-sectional shape of the upstanding stops 94 of
 the blade carrying member 28. A pin 114 is provided in the upper cavity
 102 across the opening 108. The pin 114 is fixed within aligned apertures
 116 of the housing 24. In use the hooks 96, 98 of the blade carrying
 member 28 are engageable with the pin 114 to provide a hooked connection
 117. The housing 24 further includes a spigot 118 to enable it to be
 attached to a post 120, and wear resistant abutment portions 122 against
 which the edge of the can moves in use.
 The can opener 20 in its assembled form can be seen in FIGS. 3 and 4. The
 operating handle 22 is drivably connected to the spindle 36, which in turn
 is supported for rotation in the housing 24 by the bush 38 and the
 aperture 54 in the cam follower 52. An upper portion of the cam follower
 52 projects through the cut out portion 112 of the housing roof 110. The
 wheel 40 is drivably connected to the spindle 36 and the edge 44 thereof
 projects through the opening 68 defined by the lower cavity 104. The blade
 carrying member 28 is pivotally connected to the housing 24 by the hooked
 connection 117, while the fingers 90, 92 of the blade carrying member 28
 are received in the recesses 60 of the cam follower 52. The upstanding
 stops 94 of the blade carrying member 28 project into the cut out portion
 recesses 124.
 As shown in FIGS. 3 and 4 the operating handle 22 can be pivoted between an
 upright position and a substantially horizontal position. It will be noted
 that in the upright position the distance between the pivot pin 50 and the
 cam surface 48 is greater than when the operating handle 22 is in the
 horizontal position. Accordingly, when the operating handle 22 is in the
 upright position, the cam surface 48 pushes the cam follower 52 into the
 upper cavity 102 and compresses the spring 46. Movement of the cam
 follower 52 causes the blade carrying member 28 to pivot about the pin
 114. This is due to the fingers 90, 92 of the blade carrying member 28
 being engaged in the recesses 60 of the cam follower 52. With the
 operating handle 22 in the upright position the blade 26 is held away from
 the wheel 40 and the can opener 20 can be positioned relative to a can
 such that blade 26 pierces the can. Subsequent movement of the operating
 handle 22 from the upright position to the horizontal position results in
 the can lip being clamped between the blade 26 and the wheel 40. Rotation
 of the operating handle 22 about the axis 42 results in rotation of the
 wheel 40 and consequently rotation of the can against the blade 26. By
 pivoting the operating handle 22 back to the upright position the can lip
 is released and the can opener 20 can be removed.
 In both the upright and horizontal operating handle 22 positions the
 upright stops 94 of the blade carrying member 28 project into their
 respective recesses 124. Accordingly the blade carrying member 28 is
 restricted to pivotal movement about the pin 114 and cannot be moved so as
 to disengage the hooks 96, 98 from the pin 114. Any attempt to move the
 blade carrying member 28 so as to disengage the hooks 96, 98 from the pin
 114 is resisted by the upstanding stops 94 coming into contact with the
 edge of the cut out portion 112.
 Removal of the blade carrying member 28 is effected by moving the operating
 handle 22 firstly to the upright position and then pivoting it over-centre
 as shown in FIG. 5.
 Over-centre movement of the operating handle 22 further increases the
 distance between the pivot pin 50 and the cam surface 48. This results in
 the cam follower 52 being pushed further into the upper cavity 102, the
 spring 46 being further compressed, and consequent additional pivotal
 movement of the blade carrying member 28. Sufficient over centre movement
 of the operating handle 22 results in the blade carrying member 28 being
 pivoted to such an extent that the upstanding posts 94 are moved clear of
 their recesses 124. The blade carrying member 28 can then be disengaged
 from the pin 114 and withdrawn from the upper cavity 102 as shown in FIG.
 6.
 Once the blade carrying member 28 has been removed, the blade 26, blade
 carrying member 28 and upper cavity 102 can be cleaned. The screw type
 fasteners 82 can be removed and the blade 26 easily separated from the
 blade carrying member 28. Refitting of the blade carrying member 28 is
 achieved by reversing the steps described above.
 In the embodiment described the blade carrying member 28 is provided with a
 pair of hooks 96, 98. It is envisaged that in alternative embodiments the
 blade carrying member may be provided with a single hook. Such a hook may
 be centrally positioned between opposing sides of the blade carrying
 member, or alternatively may extend fully across the blade carrying
 member. The blade carrying member 28 shown in FIG. 7 has a single hook 126
 and a single upstanding stop 128. The pin 114 may be replaced by opposing
 stub axles which project into the upper cavity 102 from opposing sides of
 the cavity wall 106. In yet a further embodiment the blade carrying member
 28 may be provided with stub axles which locate in slots provided in the
 cavity wall 106.
 To reduce manufacturing costs it is envisaged that the blade carrying
 member 28 be injection moulded from a plastics material. In such an
 embodiment the blade 26 may be incorporated into the blade carrying member
 28 during the moulding process.
 Referring again to FIG. 7 there is shown an alternative arrangement for
 engaging the blade carrying member 28 with the cam follower 52. Here the
 cam follower 52 is provided with a projection 130 which is received in a
 slot 132 provided in the blade carrying member 28. On either side of the
 slot 132 the blade carrying member 28 is shaped so as to correspond with
 the shape of the cam follower 52.
 Referring now to FIGS. 8 to 11 there is shown an alternative cam follower
 52, stop 94 and spring 46 arrangement. Components common to the previously
 described examples will be identified with like numerals. In the
 arrangement shown the blade carrying member 28 has a single hook 96 (FIGS.
 8, 10, and 11) and a single upstanding stop 94 positioned midway between
 the arms 90, 92. The cam follower 52 is, as before, substantially D-shaped
 when viewed in plan and is adapted to receive the arms 90, 92 of the blade
 carrying member 28 in use. However, instead of having a recessed under
 surface, the centre 144 cam follower 52 is substantially hollow and has an
 opening 134 in a side face 136 thereof through which the arms 90, 92 can
 project. The spring 46 is longer and has a smaller external diameter than
 that shown in the previously described example. The spring 46 projects
 into the hollow centre 144 of the cam follower 52 via an aperture 138 in
 its base 140 and rests against a seat 142 in the cam follower 52. The cam
 follower 52 is further provided with a recess 146 in the side face 136
 into which the stop 94 is received in use.
 FIGS. 9 and 10 show an assembled can opener 20. The blade carrying member
 28 is pivotally attached to the housing 24 by the pin 114 and the arms 90,
 92 project into the centre 144 via the opening 134. The spring is
 positioned between the seat 66 in the housing 24 and the cam follower seat
 142, and passes between the arms 90, 92 of the blade carrying member 28.
 The stop 94 lies in the recess 146 of the cam follower 52.
 The longer spring 46 means that a spring with a lower spring rate can be
 used with the result that operation of the can opener 20 is made easier.
 In the can opener 20 of the present invention, the cam follower 52 and
 spring 46 need to be compressed further into the housing 24 to enable
 removal of the blade carrying member than is required during normal
 operation. Typically the stroke length during normal operation is in the
 region of 3 mm, whereas a stroke of around 9 mm is required to enable the
 blade carrying member 28 to be released. The use of a longer spring may
 also make the can opener easier to assemble by reducing the force which
 has to be overcome when the spindle 36 is connected to the drive wheel 40,
 for example by the use of complementary screw threads on each component.
 FIG. 11 shows a further example of a can opener 20 having the cam follower
 52, stop 94 and spring 46 arrangement described above and including an
 additional spring 148. The additional spring 148 is provided
 concentrically about the other spring 46 and is positioned in a lower
 portion of the housing 24 below the cam follower 52. The use of an
 additional spring 148 increases the clamp force between the drive wheel 40
 and the blade 26. An increase in clamp force increases the traction
 between the drive wheel 40 and the can and hence reduces the possibility
 of the drive wheel 40 slipping.
 Referring now to FIGS. 12 to 14C there is shown a can opener having a
 further alternative cam follower and stop arrangement. As before,
 components common to the previously described examples will be described
 with like numerals. In the embodiment shown, the cam follower takes the
 form of an inverted cup 150, the interior of which is adapted to receive
 the spring (not shown). The base 152 of the cup 150 is provided with a
 hole 154 through which the spindle projects, in use, and a seating surface
 156 for the spring is provided around the hole 154. Aligned slots 158,
 which are adapted to receive the arms 90, 92 of the blade carrying member
 28, are provided in the wall 160 of the cup 150. The blade carrying member
 28 is provided with a single upstanding stop 94 positioned substantially
 midway between the arms 90, 92. When the blade carrying member 28 is
 fitted to the housing 24, the stop 94 is received in a recess 162 of the
 housing 24. The portion of the wall 160 of the cam follower 150 facing the
 recess 162 is flattened 164 to accommodate the stop 94 of the blade
 carrying member 28. The can opener is operated substantially as
 hereinbefore described with reference to the previous embodiments.
 Overcentre movement of the operating handle depresses the cam follower 150
 into the housing 20 and pivots the blade carrying member 28. Sufficient
 overcentre movement of the operating handle moves the stop 94 clear of the
 recess 162 and permits the blade carrying member 28 to be disengaged from
 the pin 114.
 The inverted cup cam follower 150 can be manufactured from a plastics
 material, for example by injection moulding, and allows a relatively long
 spring to be used. As noted above, the use of a longer spring with a lower
 rate reduces the spring force which has to be overcome when moving the
 operating handle overcentre.