GB2325209A - Can opener with cranked handle - Google Patents

Abstract

A hand-held can opener which operates by gripping a can between an engagement wheel 14, 105 and a cutting wheel 13, 103a, comprises a cranked handle 20,100 which may be connected, via gearing, to either the engagement wheel (see figures 1, 2), or to the cutter wheel (figures 3, 4), with the other wheel freely rotatable. The cranked handle is directly connected to a shaft (21, figures 1, 3), and the gearing is arranged so that when the handle is rotated, the rotation rate of the engagement or cutter wheel is less than the rotation rate of the shaft, preferably 1/2 to 1/4 of the shaft's rotation rate. The gear means may comprise a toothed wheel 15, 104 mounted on the shaft, with a diameter smaller than that of the engagement or cutter wheel. The opener also comprises two pivotally connected arms 11a, 11b, with the engagement wheel mounted on one, and the cutter wheel mounted on the other, so that when one arm is swung towards the other, the engagement and cutter wheels are moved toward each other to grip and pierce a can. Shaping means 40, 41 fold over exposed sharp edges of the can lid.

Description

A CAN OPENER The present invention relates to a can opener which is hand-held and manually-operable.

At present hand-held, manually-operable can openers are widely available. They typically comprise a rotatable cutting wheel and a drive wheel, both mounted on a support. A first handle is attached to support and comprises two arms pivotable relative to each other. The two arms can be held together in one hand. The cutting wheel is mounted on the support in such a way that it can be moved in a translational fashion along the face of the support and a mechanism is provided which converts the pivoting motion of the arms of the first handle into a translational motion to cause the cutting wheel to move along the face of the support. The drive wheel has teeth for engaging a can to be cut and when the drive wheel rotates it causes rotation of the can, which then moves relative to the cutting wheel and the can is sliced.

In the can openers currently available which are hand-held and manually-operable, the drive wheels are provided on a shaft which is rotatably mounted in the support. The shaft extends through the support from the drive wheel to connect the drive wheel to a butterfly-type handle provided at the other end of the shaft. To use the can opener, the user holds in one hand the can opener using the first handle and holds the butterfly-type second handle with his other hand and twists the butterfly-type handle by a turning action of the wrist. This turning action of the wrist is hard work and is very difficult for people with rheumatism or some types of other physical disability.

In the past, it has also been known to provide can openers which are either mounted on a wall or fixed to a surface such as a table. An example of such a can opener is given in German patent specification DE-3627967. In this patent specification a table mounted can opener is shown.

This table mounted can opener has in common with a hand-held can opener both a drive wheel and a rotatable cutting tool. However, the table mounted can opener obviously does not require a first handle for steading of the can opener, since it is secured to a table. Instead, the can opener has only one handle, which is connected by a shaft to the drive wheel to allow rotation of the drive wheel by the user of the can opener. In fact, the shaft is also connected by gearing to the rotatable cutting tool, the gearing operating in such a way that a first speed of rotation at the shaft gives a higher speed of rotation of the cutting wheel. The handle provided for the table mounted can opener is a cranked handle, comprising a first portion which extends radially from the shaft and which connects the shaft to a second portion of the second handle which provides for manual engagement of the handle. In the illustrated embodiments the second portion of the handle is a rotatable knob mounted at the end of the first radially extending portion of the second handle. Using the handle of the table mounted can opener the user effects rotation by a movement of the whole arm, rather than a movement of the wrist. The first portion of the second handle is lengthened to give a mechanical advantage to the user so that he does not have to apply much torque at all in order to effect opening of the can.

The present invention provides a can opener which is hand-held and manually-operable and which comprises: a cutting tool for cutting a can; a rotatable drive wheel engageable with the can; a support on which the cutting tool and the drive wheel are mounted; and a first handle connected to the support; wherein the drive wheel is connected to a shaft for rotation with rotation of the shaft, the shaft being rotatably mounted in the support and the shaft being connected to a second handle; and a user of the can opener can hold the first handle in one hand to steady the can opener whilst rotating the second handle with the other hand to thereby rotate the drive wheel which will cause relative motion between the can to be opened and the cutting tool whereby the cutting tool can slice through the can; characterised in that: the second handle is cranked, the second handle having a first portion which extends radially out from the shaft and which connects the shaft to a second portion of the second handle which provides for manual engagement of the handle.

In the past, designers of can openers have either designed hand-held and manually-operable can openers with butterfly-type rotatable handles or have designed wall mounted or table mounted can openers with cranked rotatable handles. The present invention departs from accepted practice by providing a hand-held and manually-operable can opener which has a cranked rotatable handle. This innovation provides a handheld can opener which is much easier to use than the traditional can opener, because the rotating motion is effected by movement of the whole arm of the user, rather than by twisting of a wrist. The wrist twisting action can prove hard work and also can be extremely difficult for people with physical handicaps such as arthritis.

In one embodiment the drive wheel is directly mounted on the shaft. This is the simplest embodiment.

Preferably, the drive wheel and the shaft are connected by gear means. Preferably when the shaft is rotated by manual rotation of the second handle at a first speed of rotation, the gear means relays the rotation to the drive wheel and rotates the drive wheel at a second lower speed of rotation. The provision of gearing facilitates the use of a cranked second handle which is not disproportionately long in relation to the remainder of the hand-held can opener.

As can be seen in the document DE-3627967, with wall mounted or table mounted can openers, the radially extending portion of the cranked handle was always designed to be of a significant length, to provide a mechanical advantage to the user so that the user does not have to apply a significant torque to open the can. With a hand-held can opener, it is not practical to have a cranked handle of a significant length and instead is preferable to use the gear means to provide the required mechanical advantage. Furthermore, the gears means is necessary in the hand-held can opener because otherwise the torque applied to the turning handle would be such that it would be difficult to hold the can opener steady during opening. Instead, with the present invention the force that is required to be applied to the cranked handle can be made very light so that there is no difficulty at all in holding the can opener steady.

Preferably the second speed of rotation (of the drive wheel) is 1/4 to 1/2 of the first speed of rotation (of the shaft).

In one embodiment the drive wheel is rotatably mounted on the support for rotation about a first axis and the shaft is rotatably mounted in the support for rotation about a second axis parallel to and spaced apart from the first axis. In this embodiment preferably the drive wheel is toothed and of a first diameter and the gear means comprises a toothed gear of a second smaller diameter which is mounted directly on the shaft and which engages the toothed drive wheel. This is the simplest way of effecting a gear train.

In a further embodiment the cutting tool can be moveable translationally relative to a support and in this embodiment the first handle will comprise first and second arms, the first arm being pivotally connected to the support and being pivotable relative to the second arm. A mechanism will be provided to connect the cutting tool to the first arm, the mechanism converting the pivotal motion of the first arm into translational motion of the cutting tool.

This allows the cutting tool to be urged to initially pierce the can by pivoting the first arm relative to the second arm.

In a second aspect the present invention provides a can opener which is hand-held and manually-operable and which comprises: a rotatable cutting tool for cutting the can; engagement means for engaging the can and steadying the can during cutting; a support on which the cutting tool and the drive wheel are mounted; and a first handle connected to the support; wherein the rotatable cutting tool is connected to a shaft for rotation with rotation of the shaft, the shaft being rotatably mounted in the support and the shaft being connected to a second handle; and a user of the can opener can hold the first handle in one hand to steady the can opener whilst rotating the second handle with the other hand to thereby rotate the rotatable cutting tool which will cause relative motion between the can being cut and the cutting tool whereby the cutting tool can slice through the can; characterised in that: the second handle is cranked, the second handle having a first portion extending radially out from the shaft and which connects the shaft to a second portion of the second handle which provides for manual engagement of the handle.

Instead of the rotatable cutting wheel being connected to the shaft as in the first aspect of the invention, the cutting tool itself can be rotatable and connected to the shaft. The rotatable cutting tool can be mounted directly on the shaft, but is preferably connected to the shaft by gear means.

Preferably when the shaft is rotated by manual rotation of the second handle at a first speed of rotation, the gear means relay the rotation to the rotatable cutting tool and rotates the cutting tool at a second lower speed of rotation. Preferably the second speed of rotation is 1/4 to 1/2 of the first speed of rotation. This is easily achieved by mounting the rotatable cutting tool on the support for rotation about a first axis and mounting the shaft rotatably in the support for rotation about a second axis parallel to and spaced apart from the first axis.

In these circumstances the cutting tool preferably has a toothed portion of a first diameter and the gear means comprises a tooth gear of a second smaller diameter which is mounted directly on the shaft and which engages the toothed portion of the rotatable cutting tool. By providing gear means, the need for a long radially extending portion of the cranked handle is avoided and also the gear means facilitates the easy steadying of the can opener using the first handle, since there will not need to be a great deal of torque applied on the second handle in order to effect opening of the can.

In the second aspect of the invention the engagement means preferably comprises an abutment member for abutting a part of the can and the abutment member is preferably moveable translationally relative to the support. In this embodiment the first handle would comprise first and second arms, the first arm being pivotably connected to the support and being pivotable relative to the second arm. A mechanism would be provided to connect the second arm to the abutment member, the mechanism converting pivotal motion of the first arm into translational motion of the abutment member. Thus, the abutment member can be brought into abutment with a part of the can and can then force the can on to the cutting tool to initially pierce the can.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a top perspective view of a first embodiment of can opener according to the invention, shown partly disassembled to better illustrate certain components; Figure 2 is an underneath plan view of the can opener shown in Figure 1; Figure 3 is a top perspective view of a second embodiment of can opener according to the present invention shown partly disassembled to better illustrate certain components; and Figure 2 is an underneath plan view of the can opener of Figure 3.

Referring to the drawings, the first embodiment of can opener can be seen in Figure 1 to comprise a support 10 connected to a handle 11 which comprises two arms lia and lib, the arm lib being fixed to the support 10 and the arm lla being pivotally mounted to support 10 by the pivot 12.

In Figure 2 it can be seen that a cutting wheel 13 is mounted on the support 10 and a drive wheel 14 is also mounted on the support 10, the drive wheel 14 being provided with teeth and the drive wheel 14 being engaged by an intermediate gear 15, also rotatably mounted on the support 10.

The cutting wheel 13 is mounted on a shaft 17 which extends through a slot 16 in the support 10.

The shaft 17 is secured to the arm ila and moves with the arm lia, so that movement of the arm lia in the direction of the arrow A shown in Figure 1 causes movement of the cutting wheel 13 in the direction of the arrow B shown in Figure 2. Thus, the initial piercing of a can to be opened is facilitated by gripping the two arms lla and llb of the first handle 11 in one hand and bringing them together (with the driving wheel 14 secured to the inner side of the top rim of a can and the cutting wheel 13 engaging the exterior surface of the can). Pivoting of the arm llb in the opposite sense to that of the arrow A causes the cutting wheel 13 to move in the opposite sense to that of the arrow B and thereby allows removal of a cut lid from the can opener once the lid has been cut.

A novel part of the can opener shown in Figures 1 and 2 is the mechanism for rotating the drive wheel 14. The drive wheel 14 is pivotally mounted to the support 10 on a first axis. It is engaged by the gear 15 which is mounted on a shaft 21 which extends through the support 10 along a second axis parallel to and spaced from the axis of the drive wheel 14. The shaft 21 has a splined end, which engages with splines (not shown) provided in a hub portion 22 of a cranked second handle 20. The handle 20 has a first portion 20a which extends radially out from the shaft 21 and on the portion 20b is rotatably mounted a freely rotatable knob 23. The Figure 1 shows that the hub portion 22 of the second handle 20 extends through an aperture in a cover 30 which in use is connected to the remainder of the support 10 and forms part of the support 10, but which is shown disconnected in Figure 1 for ease of explanation.

With the can opener of Figures 1 and 2, once the can has been initially pierced by the cutting wheel 13 (by the pivoting together of the two arms lla and lib), then the can is driven to rotate relative to the can opener by the drive wheel 14. The drive wheel 14 is driven to rotate by the user by gripping the rotatable knob 23 and then rotating the arm 20. The arm 20 engages the shaft 21 and causes the shaft 21 to rotate, thereby rotating the intermediate gear 15, which is mounted directly on the shaft 21. The rotating gear 15 then rotates the driving wheel 14.

The radius of the intermediate gear 15 is preferably chosen to be half of the radius of the driving wheel 14. This gives a significant mechanical advantage. The user need not apply much torque to the handle 20 to cause rotation. Also the use of the intermediate gear enables the user to apply sufficient torque to the handle 20 with the handle 20 having a radially extending portion 20a which is not overly long. Typically the portion 20a will be 2-3 inches or 5-8cm long.

In order to rotate the handle 20, the user will use his whole arm rather than just a wrist and this makes the job of opening a can easier and indeed may facilitate handicapped people opening cans, where this had not been possible with normal cans.

In a preferred embodiment, the can opener would be provided with further metal shaping tools 40 and 41, which initially engage the exterior surface of the can when the can is initially pierced by the cutting tool 13, but afterwards can ac- to bend over the cut edge of the can in order to rt zve the danger of sharp edges. This is possible with the present can opener, because the mechanical advantage provided to the user by the cranked handle 20 and the gear 15 enable the metal turning operation to be effected without too much effort by the user.

In the second embodiment of the invention shown in Figures 3 and 4, the majority of components are the same and therefore will not be described. The only components which will be described are the ones that are different. In the second embodiment shown in Figures 3 and 4, the cranked lever arm has been replaced by a circular disc 100 having mounted thereon a knob 101, which is freely rotatable. It will be appreciated that the disc 100 forms that part of the operating handle which extends radially of the shaft 21. The circular disc 100 provides the same mechanical advantage as the lever arm 20 of the first embodiment, but can be easier to manufacture and can be more aesthetically pleasing.

The second embodiment also differs in that in the second embodiment the cutting wheel 103 is driven to rotate, rather than a driving wheel. The cutting wheel 103 comprises both a cutting portion 103a shown in solid lines in Figure 4 and also an underlying tooth portion 103b shown in dotted lines in Figure 4.

The underneath tooth portion 103b engages an intermediate gear 104 which is shown partly in solid lines and partly in dotted lines in Figure 4. The gear 104 is connected by the shaft 21 to the circular disc 100, so that rotation of the disc 100 can cause rotation of the cutting wheel 103.

In the second embodiment, an engaging wheel 104 is provided which can engage the can to be cut and hold the can to be cut steady during cutting.

However, unlike the first embodiment, the engaging wheel 104 is not a driven wheel. Instead it is freely rotatable. In the second embodiment, it is the freely rotatable engaging wheel 105 which is moveable translationally relative to the support 10, in the same way that the cutting wheel 13 is translationally moveable in the first embodiment.

The second embodiment does not have bending tools for bending over the cut edge of a can.

Whilst in the embodiments described above intermediate gears 15 and 104 are described connecting a cranked handle 20 or 100 to a driving wheel 14 or a driven cutting wheel 103, the applicant has considered a less preferred embodiment of having direct connection of the handle 20 or the disc 100 to the driven wheel 14 or the cutting wheel 103. For instance, the driven wheel 14 could be mounted directly on the shaft 21 and therefore connected directly to the handle 20 or the cutting wheel 103 could be mounted directly on the shaft 21 and connected thereby to the disc 100. This option is less preferred because it does not include the mechanical advantage of having gearing. However, with a suitable choice of length of the portion 20a of handle 20 or the diameter of the circular disc 100, it may be possible to produce a simplified but still effective hand-held manually-operable can opener.

It should be appreciated that it is not essential to the invention to have a handle 11 comprised of two arms 11a and 11b pivotable relative to each other and it is not essential to have either the engaging wheel 104 or the cutting wheel 13 translationally moveable in response to such pivotal motion. Indeed, the drive wheel (eg 14) and the cutting wheel (eg 13) could both be fixed in position, provided that the can could still be inserted between the drive wheel 14 and the cutting wheel 13 (or the cutting wheel 103 and the engaging wheel 105).

Whilst in the first embodiment shown in Figures 1 and 2 above, the driving wheel 14 is driven and the cutting wheel 13 is freely rotatable, gearing could be provided to connect the cutting wheel 13 to the handle 20, either directly or via the driving wheel 14. In such an embodiment both the driving wheel 14 and the cutting wheel 13 will be driven to rotate. Similarly, in the embodiment shown in Figures 3 and 4, the engaging wheel 105 could be made a driving wheel by connecting it via gears to the disc 100 either directly or via the cutting wheel 103.

In both of the preferred embodiments described above the intermediate gear 15 is provided on the exterior of the can opener. However, it could be preferred that the embodiment of Figures 1 and 2 has a drive wheel 14 on a shaft extending within the support 10 into a cavity within the support 10, and the shaft would have a gear mounted thereon within the cavity which would engage a gear mounted on the shaft 21 also within the cavity. The embodiment of Figures 3 and 4 could be modified so that the gear 15 could be within a cavity in the support 10 and the cutting wheel 103 would be on a shaft extending into the cavity with a gear on the shaft in the cavity engaging with the gear 15.

A can opener with a cavity in the support in which a gear connects the shaft 21 to the drive wheel 14 or cutting wheel 103 enables the gear assembly to be manufactured as a separate entity for subsequent inclusion in the can opener.

It should also be appreciated that whilst in the illustrated embodiments there is only one intermediate gear 15 in each embodiment, a plurality of intermediate gears could be used to connect the drive wheel 14 or the cutting wheel 103 with the shaft 21.

Claims (15)

1. A can opener which is hand-held and manuallyoperable and which comprises: a cutting tool for cutting a can; a rotatable drive wheel engageable with the can; a support on which the cutting tool and the drive wheel are mounted; and a first handle connected to the support; wherein the drive wheel is connected to a shaft for rotation with rotation of the shaft, the shaft being rotatably mounted in the support and the shaft being connected to a second handle; and a user of the can opener can hold the first handle in one hand to steady the can opener whilst rotating the second handle with the other hand to thereby rotate the drive wheel which will cause relative motion between the can to be opened and the cutting tool whereby the cutting tool can slice through the can; characterised in that: the second handle is cranked, the second handle having a first portion which extends radially out from the shaft and which connects the shaft to a second portion of the second handle which provides for manual engagement of the handle.

2. A can opener as claimed in claim 1 wherein the drive wheel is mounted directly on the shaft.

3. A can opener as claimed in claim 1 wherein the drive wheel and the shaft are connected by gear means.

4. A can opener as claimed in claim 3 wherein when the shaft is rotated by manual rotation of the second handle at a first speed of rotation, the gear means relays the rotation to the drive wheel and rotates the drive wheel at a second lower speed of rotation.

5. A can opener as claimed in claim 4 wherein the second speed of rotation is 1/4 to 1/2 of the first speed of rotation.

6. A can opener as claimed in any one of claims 3 to 5 wherein the drive wheel is rotatably mounted in the support for rotation about a first axis and the shaft is rotatably mounted in the support for rotation about a second axis parallel to and spaced apart from the first axis.

7. A can opener as claimed in claim 6 wherein the drive wheel is toothed and of a first diameter and the gear means comprises a toothed gear of a second smaller diameter which is mounted directly on the shaft and which engages the toothed drive wheel.

8. A can opener as claimed in any one of the preceding claims wherein: the cutting tool is moveable translationally relative to the support; the first handle comprises first and second arms; the first arm is pivotally connected to the support and is pivotable relative to the second arm; and a mechanism is provided which connects the cutting tool to the first arm and converts pivotal motion of the first arm into translational motion of the cutting tool whereby the cutting tool can be urged to initially pierce the can by pivoting the first arm relative to the second arm.

9. A can opener which is hand-held and manuallyoperable and which comprises: a rotatable cutting tool for cutting the can; engagement means for engaging the can and steadying the can during cutting; a support on which the cutting tool and the engagement means are mounted; and a first handle connected to the support; wherein the rotatable cutting tool is connected to a shaft for rotation with rotation of the shaft, the shaft being rotatably mounted in the support and the shaft being connected to a second handle; and a user of the can opener can hold the first handle in one hand to steady the can opener whilst rotating the second handle with the other hand to thereby rotate the rotatable cutting tool which will cause relative motion between the can being cut and the cutting tool whereby the cutting tool can slice through the can; characterised in that: the second handle is cranked, the second handle having a first portion which extends radially out from the shaft and which connects the shaft to a second portion of the second handle which provides for manual engagement of the handle.

10. A can opener as claimed in claim 9 wherein the rotatable cutting tool is mounted directly on the shaft.

11. A can opener as claimed in claim 10 wherein the rotatable cutting tool and the shaft are connected by gear means.

12. A can opener as claimed in claim 11 wherein when the shaft is rotated by manual rotation of the second handle at a first speed of rotation, the gear means relays the rotation to the rotatable cutting tool and rotates the cutting tool at a second lower speed of rotation.

13. A can opener as claimed in claim 12 wherein the second speed of rotation is 1/4 to 1/2 of the first speed of rotation.

14. A can opener as claimed in any one of claims 11 to 13 wherein the rotatable cutting tool is rotatably mounted on the support for rotation about a first axis and the shaft is rotatably mounted in the support for rotation about a second axis parallel to and spaced apart from the first axis.

15. A can opener substantially as herebefore described with reference to and as shown in the accompanying drawings.

15. A can opener as claimed in claim 14 wherein the rotatable cutting tool has a toothed portion of a first diameter and the gear means comprises a toothed gear of a second smaller diameter which is mounted directly on the shaft and which engages the toothed portion of the rotatable cutting tool.

16. A can opener as claimed in any one of claims 9 to 15 wherein: the engagement means comprises an abutment member for abutting a part of the can and the abutment member is moveable translationally relative to the support; the first handle comprises first and second arms; the first arm is pivotally mounted to the support and is pivotable relative to the second arm; and a mechanism is provided which connects the second arm to the abutment member and converts pivotal motion of the first arm into translational motion of the abutment member whereby the abutment member can be brought into abutment with a part of can and can then force the can on to the cutting tool to initially pierce the can.

17. A can opener as claimed in any one of the preceding claims wherein the second portion of the second handle extends away from the first portion of the second handle along an axis substantially parallel to the axis of the shaft.

18. A can opener as claimed in claim 8 wherein a manually engageable knob is rotatably mounted on the second portion of the second handle for free rotation about the axis thereof.

19. A can opener as claimed in any one of the preceding claims comprising additionally a bending tool mounted on the support for bending over an edge of the can once cut by the cutting tool.

20. A can opener substantially as herebefore described with reference to and as shown in the accompanying drawings.

Amendments to the claims have been fled as folows

1. A can opener which is hand-held and manually operable and which comprises: a cutting tool for cutting a can; a rotatable drive wheel engageable with the can; a support on which the cutting tool and the drive wheel are mounted; and a first handle connected to the support; wherein the drive wheel is connected to a shaft for rotation with rotation of the shaft, the shaft being rotatably mounted in the support and the shaft being connected to a second handle; a user of the can opener can hold the first handle in one hand to steady the can opener whilst rotating the second handle with the other hand to thereby rotate the drive wheel which will cause relative motion between the can to be opened and the cutting tool whereby the cutting tool can slice through the can; the second handle is cranked, the second handle having a first portion which extends radially out from the shaft and which connects the shaft to a second portion of the second handle which provides for manual engagement of the second handle; the drive wheel and the shaft are connected by gear means; and when the shaft is rotated by manual rotation of the second handle at a first speed of rotation, the gear means relays the rotation to the drive wheel and rotates the drive wheel at a second lower speed of rotation.

2. A can opener as claimed in claim 1 wherein the second speed of rotation is 1/4 to 1/2 of the first speed of rotation.

3. A can opener as claimed in claim 1 or claim 2 wherein the drive wheel is rotatably mounted in the support for rotation about a first axis and the shaft is rotatably mounted in the support for rotation about a second axis parallel to and spaced apart from the first axis.

4. A can opener as claimed in claim 3 wherein the drive wheel is toothed and of a first diameter and the gear means comprises a toothed gear of a second smaller diameter which is mounted directly on the shaft and which engages the toothed drive wheel.

5. A can opener as claimed in any one of the preceding claims wherein: the cutting tool is moveable translationally relative to the support; the first handle comprises first and second arms; the first arm is pivotally connected to the support and is pivotable relative to the second arm; and a mechanism is provided which in use connects the cutting tool to the first arm and converts pivotal motion of the first arm into translational motion of the cutting tool whereby the cutting tool can be urged to initially pierce the can by pivoting the first arm relative to the second arm.

6. A can opener which is hand-held and manuallyoperable and which comprises: a rotatable cutting tool for cutting the can; engagement means for engaging the can and steadying the can during cutting; a support on which the cutting tool and the engagement means are mounted; and a first handle connected to the support; wherein the rotatable cutting tool is connected to a shaft for rotation with rotation of the shaft, the shaft being rotatably mounted in the support and the shaft being connected to a second handle; and a user of the can opener can hold the first handle in one hand to steady the can opener whilst rotating the second handle with the other hand to thereby rotate the rotatable cutting tool which will cause relative motion between the can being cut and the cutting tool whereby the cutting tool can slice through the can; the second handle is cranked, the second handle having a first portion which extends radially out from the shaft and which connects the shaft to a second portion of the second handle which provides for manual engagement of the second handle; the rotatable cutting tool and the shaft are connected by gear means; and when the shaft is rotated by manual rotation of the second handle at a first speed of rotation, the gear means relays the rotation to the rotatable cutting tool and rotates the cutting tool at a second lower speed of rotation.

7. A can opener as claimed in claim 6 wherein the second speed of rotation is 1/4 to 1/2 of the first speed of rotation.

8. A can opener as claimed in claim 6 or claim 7 wherein the rotatable cutting tool is rotatably mounted on the support for rotation about a first axis and the shaft is rotatably mounted in the support for rotation about a second axis parallel to and spaced apart from the first axis.

9. A can opener as claimed in claim 8 wherein the rotatable cutting tool has a toothed portion of a first diameter and the gear means comprises a toothed gear of a second smaller diameter which is mounted directly on the shaft and which engages the toothed portion of the rotatable cutting tool.

10. A can opener as claimed in any one of claims 6 to 9 wherein: the engagement means comprises an abutment member for abutting a part of the can and the abutment member is moveable translationally relative to the support; the first handle comprises first and second arms; the first arm is pivotally mounted to the support and is pivotable relative to the second arm; and a mechanism is provided which connects the second arm to the abutment member and converts pivotal motion of the first arm into translational motion of the abutment member whereby the abutment member can be brought into abutment with a part of can and can then force the can on to the cutting tool to initially pierce the can.

11. A can opener as claimed in any one of the preceding claims wherein the second portion of the second handle extends away from the first portion of the second handle along an axis substantially parallel to the axis of the shaft.

12. A can opener as claimed in claim 11 wherein a manually engageable knob is rotatably mounted on the second portion of the second handle for free rotation about the axis thereof.

13. A can opener as claimed in claim 11 or claim 12 wherein the first portion of the second handle comprises a circular disc.

14. A can opener as claimed in any one of the preceding claims comprising additionally a bending tool mounted on the support for bending over an edge of the can once cut by the cutting tool.