Abstract:
A can opener ( 100 ) comprising a pair of handles ( 10  and  11 ), a traction wheel ( 13 ) and a cutter blade ( 14 ) for removing a lid of a can in the conventional laterally-cutting manner. Embodiments of the invention include an operating knob ( 16 ) that is supported, at one side (right side as shown) of the can opener ( 100 ), to rotate about an axis transverse to a central axis of the can. The knob ( 16 ) is coupled by means of step-down gearing ( 17  and  18 ) to the traction wheel ( 13 ). This construction renders the use of the can opener ( 100 ) much more comfortable for a user. For left-handed use, the knob ( 16 ) is fitted to the opposite (left hand) side of the can opener.

Description:
[0001]    The invention relates to a manually operable can opener which has a rotatable traction wheel and a rotatable cutter blade for lateral engagement with the rim or side wall of a metal can in order to cut open the can.  
         BACKGROUND OF THE INVENTION  
         [0002]    Manually operable can openers have been known for many years and may be broadly categorised into three types: a first type having a cutter blade which cuts directly into the top wall of a can, a second type having a cutter blade which cuts into the side wall of the can below the rim, and a third type having a cutter blade which cuts partially into the rim of the can.  
           [0003]    In the first type of can openers, the cutter blade has a rotational axis inclined to that of the traction wheel. The traction wheel and cutter blade are usually provided with respective circular gears in mesh with each other in use, whereby rotation of the traction wheel by the user in one direction causes rotation of the cutter blade in the opposite direction. In operation, the traction wheel engages the rim of a can from below, extending substantially parallel to the central or rotational axis of the can. The cutter blade penetrates completely through and cuts into the top wall of the can at a position slightly radially inwards of the rim, whereby the top wall is removable upon a complete revolution of the can about its central axis relative to the can opener. A disadvantage of this type of can openers is that metal cuttings and/or other contaminants on the outer surface of the top wall may fall into the can during opening. The cut away top wall is also difficult to remove as it may fall into the can.  
           [0004]    Can openers of the second type have a traction wheel and a cuter blade whose axes of rotation are substantially parallel to each other, in that the wheel and the blade overlie one another to some extent when the can opener is in its operative condition. The traction wheel is rotatable by the user and the cutter blade is freely rotatable. In use, the traction wheel engages the radially inner surface of the rim of a can, with its axis of rotation substantially parallel to the central axis of the can. The cutter blade laterally penetrates completely through and cuts into the side wall of the can at a position slightly below the rim, whereby the top wall including the rim of the can are removable together upon a complete revolution of the can about its central axis relative to the can opener.  
           [0005]    A can opener of the third type has been disclosed in UK Patent No. 2334939, which has a cutter blade so disposed relative to the traction wheel that in use, the cutter blade cuts into but not completely through the rim of the can. Cans are generally formed from a cylindrical metal body and two separate metal end walls, in that each end of the body and the outer edge of a respective end wall are folded together to form a sealed closure rim. The rim has five layers of metal when viewed in cross section, being a radially inner, a radially outer and a central layer of the end wall metal, and two intermediate layers of the body metal interlaced with the three layers of the end wall metal. A can opener incorporating a rim-cutting mechanism of this type is operable to cut laterally through the outermost layer of the rim. This results in the remainder of the end wall becoming releasable from the can body, thereby leaving a part of the rim in situ on the end wall and the other part of the rim in situ on the can body.  
           [0006]    The present invention is directed to the second and third types of can openers, or collectively referred to as a laterally-cutting type, which at present are uncomfortable to use and especially awkward for left-handed users.  
           [0007]    It is an object of the invention to overcome or at least reduce such problems.  
         SUMMARY OF THE INVENTION  
         [0008]    According to a first aspect of the invention, there is provided a can opener of the laterally-cutting type, comprising a pair of operating members pivotal with respect to each other, one said member mounting a rotatable traction wheel and the other said member a rotatable cutter blade. The wheel and blade are movable between an inoperative position in which the wheel and the blade are spaced apart to an extent that the rim of a can to be opened is locatable between the wheel and the blade, and an operative position in which the wheel and the blade are in close proximity and engageable with the can to effect opening thereof, in which the traction wheel and the cutter blade have respective rotational axes which in use are substantially parallel to a central axis of the can. The can opener includes a housing formed on said one member, an operating element provided on one side of the can opener and supported by the housing and arranged to rotate about an axis generally transverse to the central axis of the can, and gearing provided in the housing mechanically coupling the operating element to the traction wheel.  
           [0009]    Preferably, the gearing comprises two bevel gears.  
           [0010]    For convenience of operation, the gearing is arranged to provide a mechanical advantage for the operating element.  
           [0011]    It is preferred that the operating element is in the form of a butterfly knob.  
           [0012]    In a preferred embodiment, the rotational axis of the operating element is inclined upwards at an angle in the range of 0° to 45° with respect to the plane of rotation of the traction wheel.  
           [0013]    Specifically, the can opener is one of the third type as hereinafter defined.  
           [0014]    According to a second aspect of the invention, there is provided a can opener of the laterally-cutting type, comprising a pair of operating members pivotal with respect to each other in use about a substantially vertical axis, one said member mounting a rotatable traction wheel and the other said member mounting a rotatable cutter blade. The wheel and the blade are movable between an inoperative position in which the wheel and the blade are spaced apart to an extent that the rim of a can to be opened is locatable between the wheel and the blade, and an operative position in which the wheel and the blade are in close proximity and engageable with the can to effect opening thereof. The can opener includes a housing formed on said one member, an operating element provided on one side of the can opener and supported by the housing and arranged to rotate about an axis generally transverse to the central axis of the can when the opener is in use on the can, and gearing provided in the housing mechanically coupling the operating element to the traction wheel.  
           [0015]    Preferably, the gearing comprises two bevel gears.  
           [0016]    For convenience of operation, the gearing is arranged to provide a mechanical advantage for the operating element.  
           [0017]    It is preferred that the operating element is in the form of a butterfly knob.  
           [0018]    In a preferred embodiment, the rotational axis of the operating element is inclined upwards at an angle in the range of 0° to 45° with respect to the plane of rotation of the traction wheel.  
           [0019]    Specifically, the can opener is one of the third type as hereinafter defined.  
           [0020]    According to a third aspect of the invention, there is provided a can opener of the laterally-cutting type, comprising a pair of operating members pivotal with respect to each other in use about a substantially vertical axis, one said member mounting a rotatable traction wheel and the other said member mounting a rotatable cutter blade. The wheel and the blade are movable between an inoperative position in which the wheel and the blade are spaced apart to an extent that the rim of a can to be opened is locatable between the wheel and the blade, and an operative position in which the wheel and the blade are in close proximity and engageable with the can to effect opening thereof. The can opener includes a housing formed on said one member, and an operating element provided on one side of the can opener and supported by the housing for rotating the traction wheel. Said one side of the opener is the left side to a user when the opener is used on the can by the user. The element is rotatable about an axis extending at an angle in the range of 45° to 90° downwards from the rotational axis of the traction wheel.  
           [0021]    Preferably, the can opener further includes gearing provided in the housing mechanically coupling the operating element to the traction wheel.  
           [0022]    More preferably, the gearing comprises two bevel gears.  
           [0023]    For convenience of operation, the gearing is arranged to provide a mechanical advantage for the operating element. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0024]    The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which:  
         [0025]    [0025]FIG. 1 is a top plan view of a first embodiment of a can opener in accordance with the invention, said can opener being for right-handed use;  
         [0026]    [0026]FIG. 2 is a bottom plan view of the can opener of FIG. 1, shown in operation cutting open a can;  
         [0027]    [0027]FIG. 3 is a cross-sectional front end view of the can opener of FIG. 1;  
         [0028]    [0028]FIG. 4 is a cross-sectional top plan view of the can opener of FIG. 1;  
         [0029]    [0029]FIG. 5 is an exploded front end view of the can opener of FIG. 1;  
         [0030]    [0030]FIG. 6 is a top plan view of a second embodiment of a can opener in accordance with the invention, said can opener being for left-handed use;  
         [0031]    [0031]FIG. 7 is a bottom plan view of the can opener of FIG. 6, shown in operation cutting open a can;  
         [0032]    [0032]FIG. 8 is a cross-sectional front end view of the can opener of FIG. 6;  
         [0033]    [0033]FIG. 9 is a cross-sectional top plan view of the can opener of FIG. 6;  
         [0034]    [0034]FIG. 10 is an exploded front end view of the can opener of FIG. 6;  
         [0035]    [0035]FIG. 11 is a rear end perspective view of a slightly different can opener, which is based on the can opener of FIG. 6;  
         [0036]    [0036]FIG. 12 is a rear end perspective view of a third embodiment of a can opener in accordance with the invention, said can opener being for right-handed use;  
         [0037]    [0037]FIG. 13 is a bottom plan view of the can opener of FIG. 12;  
         [0038]    [0038]FIG. 14 is an exploded perspective view of the can opener of FIG. 12;  
         [0039]    [0039]FIG. 15 is a cross-sectional side view of the can opener of FIG. 12, shown in operation cutting open a can;  
         [0040]    [0040]FIG. 16 is a bottom plan view of a fourth embodiment of a can opener in accordance with the invention, said can opener being for left-handed use; and  
         [0041]    [0041]FIG. 17 is an exploded perspective view of the can opener of FIG. 16.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0042]    Referring initially to FIGS.  1  to  10  of the drawings, there are shown a right-handed can opener  100  (FIGS.  1  to  5 ) and a left-handed can opener  200  (FIGS.  6  to  10 ) embodying the invention, which have very similar constructions and belong to the aforesaid laterally-cutting type in general or more specifically the third type as disclosed in UK Patent No. 2334939. Each can opener  100 / 200  has a pair of operating members in the form of handles  10  and  11 , which are connected together for pivotal movement relative to each other in use about a substantially vertical axis. The handles  10  and  11  mount, at their front ends, a traction wheel  13  and a circular cutter blade  14  (in a cylindrical assembly) respectively for rotation about separate generally vertical axes such that, upon pivoting close together, a rim of a can  12  gripped by and between the traction wheel  13  and the cutter blade  14  can be cut open by the blade  14 .  
         [0043]    An operating element, in the form of a butterfly knob  16 , is connected indirectly to an axle  13 A of the traction wheel  13  (directly in the case of known constructions), which is turned to rotate the can  12  relative to the can opener  100 / 200 . As a result, an outermost layer of the rim is cut open so that the top wall concerned or the lid so formed can be removed from the body of the can  12 .  
         [0044]    For either can opener  100 / 200 , the handle  10  includes a front end housing  15  which rotatably supports the operating knob  16  on one side. The knob  16  is indirectly connected to the traction wheel  13  by means of a pair of bevel gearwheels  17  and  18  mounted within the housing  15 .  
         [0045]    In the case of the can opener  100 , the operating knob  16  is provided on the right hand side of the can opener  100  for use by a right-handed user. The first gearwheel  17  is connected directly to an axle  16 A of the operating knob  16 , and the second gearwheel  18  directly to the axle  13 A of the traction wheel  13 . The second gearwheel  18  is positioned on the lower side of the first gearwheel  17 , for suiting the cutting direction of the cutter blade  14  as determined by its rotational axis being inclined at substantially  60  from the rotational axis of the traction wheel  13  as disclosed in UK Patent No. 2334939.  
         [0046]    For the other can opener  200 , the operating knob  16  is provided on the left hand side to suit a left-handed user. The gearwheels  17  and  18  are likewise connected directly to the knob axle  16 A and the wheel axle  13 A, respectively. However, the second gearwheel  18  is positioned on the upper side of the first gearwheel  17 , such that the same arrangement of the traction wheel  13  and cutter blade  14 , instead of a mirror image arrangement, can be employed in this can opener  200  for use by a left-handed user.  
         [0047]    By reason of the use of the gearwheels  17  and  18 , the rotational axis of the operating knob  16  extends transversely to the central axis of the can  12 . This allows in use for comfortable manual turning of the operating knob  16  by a right-handed or left-handed user respectively, in a position where his/her forearm can turn about a generally transverse or horizontal axis for opening the can  12 . Compared with conventional can openers of the same type in which the operating knob is rotatable about the same axis as the traction wheel, the gearwheels  17  and  18  serve to incline the rotational axis of the knob  16  from that of the traction wheel  13  for enhanced comfort in operation.  
         [0048]    In addition, as the driving gearwheel  17  has a relatively smaller number of teeth than that of the driven gearwheel  18 , a mechanical advantage is provided so that the traction wheel  13  and cutter blade  14  can comparatively easy be turned, as required, by a user.  
         [0049]    A slightly different can opener  200 ′ is shown in FIG. 11, which has been changed based on the can opener  200 , with equivalent parts designated by the same reference numerals suffixed by an apostrophe. In this can opener  200 ′, as compared with the earlier can opener  200 , the major difference lies in the axis of rotation of the operating knob  16 ′ being inclined about 25° upwards with respect to a plane of rotation of the traction wheel  13 ′. As a result, the wings of the knob  16 ′ are in effect raised upwards, so that the knob  16 ′ can be rotated completely above the top surface plane of the can  12  without fouling the top surface. If the can  12  is circular as shown in FIGS. 2 and 7, such an uplifted operational position may not be required. However, for a laterally oval or rectangular can, the wings of the knob  16 ′ may otherwise, during use, come into contact with the top surface of the can.  
         [0050]    It is to be appreciated that tilting of the axis of rotation of the knob  16 ′ upwards from the plane of rotation of the traction wheel  13 , for an angle of 25° as shown in FIG. 11, does not impair to any great extent the overall or other advantages as provided by embodiments of the invention, that is to say it does make the turning of the knob  16 ′ much, if any, more awkward in use. In general, the rotational axis of the knob  16 / 16 ′ may be tilted upwards from the plane of rotation of the traction wheel  13  for an angle in the range of 0° to 45°, or in other words downwards from the rotational axis of the traction wheel  13  in the range of 45° to 90°.  
         [0051]    Reference is finally made to FIGS.  12  to  17  of the drawings, which show another right-handed can opener  300  (FIGS.  12  to  15 ) and another left-handed can opener  400  (FIGS. 16 and 17) embodying the invention, which belong to the aforesaid laterally-cutting type in general or more specifically the third type as disclosed in UK Patent No. 2334939. The construction of the can openers  300 / 400  is conceptually very similar to that of the earlier can openers  100 / 200 , with equivalent parts designated by the same reference numerals. Save for the gearing as shown (equivalent to the earlier gearwheels  17  and  18 ) and a housing therefor not shown (equivalent to the earlier housing  15 ), the construction of the other or like components has been fully described in UK Patent No. 2334939 and their inter-relationship and operation will be well understood by persons skilled in the art.  
         [0052]    It will be appreciated that the described embodiments of the invention, comprising the so-called laterally-cutting type in general or more specifically the third type of can openers as defined above, are therefore generally much more comfortable to use and, as is apparent from the description and drawings, readily assembled for either a left-handed or a right-handed user, making use of the same or virtually exactly the same components for assembling left-handed and right-handed can openers.  
         [0053]    It is envisaged that the subject invention may equally be applied to can openers of the second type, in that the cutter blade  14  should be lowered (slightly) to a position for cutting into the side wall of a can, right below the rim, so that the whole of the top periphery of the can becomes removable.  
         [0054]    It will be noted, as mentioned above and/or shown in the drawings, that the rotational axis of cutter blade  14  is off-set by a small angle of about 6° with respect to that of the traction wheel  13  or the can  12 , to improve the cutting action. It has also been proposed to off-set the rotational axis of the traction wheel  13  by a few degrees to improve surface gripping against the rim of the can  12  in use. Thus, where the term “substantially parallel” is used in the specification in relation to the axes of the traction wheel, the cutter blade and/or the can, it is intended to encompass appropriate off-set angles in the range of 3° to 10°.  
         [0055]    The invention has been given by way of example only, and various other modifications of and/or alterations to the described embodiments may be made by persons skilled in the art without departing from the scope of the invention as specified in the appended claims.