Abstract:
A flint wheel assembly is disclosed as including a flint wheel rotatable to rub against a flint for generating spark; and two outer wheels, each on a side of the flint wheel, and each operatively associated with the flint wheel via a respective inner wheel; wherein each outer wheel is movable substantially along its longitudinal axis between a first position in which it is out of contact with the inner wheel and a second position in which it is in contact with the inner wheel; and when the outer wheel is in the second position, the outer wheel is simultaneously rotatably movable with the flint wheel upon the application of a force on the outer wheel in a direction generally towards the inner wheel.

Description:
[0001]     This invention relates to a flint wheel assembly for use in a lighter, and, in particular, such an assembly hindering undesired operation of the lighter by children.  
       BACKGROUND OF THE INVENTION  
       [0002]     Although there are a large variety of lighters now available in the market, there are broadly speaking only two ignition methods, namely mechanical flint wheel ignition and electronic ignition. The basic structure of a conventional lighter with mechanical flint wheel ignition arrangement includes a body and an ignition unit on the top of the body. The body includes a fuel casing for accommodating a liquid fuel under pressure. As to the ignition unit, such includes a gas valve on the fuel casing, a nozzle in communication with the gas valve, a gas valve lever engaged with the nozzle, and a flint wheel adapted to be in contact with a flint and rotatable relative to the flint for generating sparks.  
         [0003]     There has not been much change to the structure of such a conventional mechanical flint wheel ignition arrangement. As sparks will be generated upon rotation of the flint wheel, such lighters are easy to use, but are also prone to easy misuse by children, possibly causing fire accidents and/or serious injury to the children.  
         [0004]     It is thus an object of the present invention to provide a flint wheel assembly, and a lighter incorporated with such a flint wheel assembly, in which the aforesaid shortcomings are mitigated, or at least to provide a useful alternative to the public.  
       SUMMARY OF THE INVENTION  
       [0005]     According to a first aspect of the present invention, there is provided a flint wheel assembly including a flint wheel adapted to be rotated to rub against a flint for generating spark; and two operating wheels, each on a side of said flint wheel, and each operatively associated with said flint wheel via a respective intermediate wheel member; wherein each said operating wheel is movable substantially along its longitudinal axis between a first position in which it is out of contact with said intermediate wheel member and a second position in which it is in contact with said intermediate wheel member; and wherein when said operating wheel is in said second position, said operating wheel is simultaneously rotatably movable with said flint wheel upon the application of a force on said operating wheel in a direction generally towards said intermediate wheel member.  
         [0006]     According to a second aspect of the present invention, there is provided a lighter including a flint wheel assembly, said flint wheel assembly including a flint wheel adapted to be rotated to rub against a flint for generating spark; and two operating wheels, each on a side of said flint wheel, and each operatively associated with said flint wheel via a respective intermediate wheel member; wherein each said operating wheel is movable substantially along its longitudinal axis between a first position in which it is out of contact with said intermediate wheel member and a second position in which it is in contact with said intermediate wheel member; and wherein when said operating wheel is in said second position, said operating wheel is simultaneously rotatably movable with said flint wheel upon the application of a force on said operating wheel in a direction generally towards said intermediate wheel member. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     Preferred embodiments of the present invention will now be described, by way of examples only, with reference to the accompanying drawings, in which:  
         [0008]      FIG. 1  is an exploded perspective view of a flint wheel assembly according to a first preferred embodiment of the present invention;  
         [0009]      FIG. 2  is a perspective view of the flint wheel assembly shown in  FIG. 1 , with one outer wheel removed;  
         [0010]      FIG. 3  is a perspective view of the flint wheel assembly shown in  FIG. 1 , as fully assembled;  
         [0011]      FIG. 4  is a sectional view of the flint wheel assembly shown in  FIG. 3  in a stable configuration;  
         [0012]      FIG. 5  shows a first alternative engagement arrangement between the outer wheel and the inner wheel in the flint wheel assembly shown in  FIG. 1 ;  
         [0013]      FIG. 6  shows a second alternative engagement arrangement between the outer wheel and the inner wheel in the flint wheel assembly shown in  FIG. 1 ;  
         [0014]      FIG. 7  shows a third alternative engagement arrangement between the outer wheel and the inner wheel in the flint wheel assembly shown in  FIG. 1 ;  
         [0015]      FIG. 8  shows a fourth alternative engagement arrangement between the outer wheel and the inner wheel in the flint wheel assembly shown in  FIG. 1 ; and  
         [0016]      FIG. 9  is an exploded perspective view of a flint wheel assembly according to a second preferred embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     FIGS.  1  to  4  show a flint wheel assembly according to a first preferred embodiment of the present invention, generally designated as  2 . The flint wheel assembly  2  includes a central flint wheel  10  with a number of parallel teeth  13  for rubbing against a flint (not shown) in a lighter (not shown) for generating spark when the central wheel  10  is rotated about its longitudinal axis L-L.  
         [0018]     A longitudinal through hole  11  is provided in the central wheel  10  for receiving, on each side, a respective spindle  33  of an inner wheel  30 . The dimension, shape and configuration of the spindles  33  of the inner wheels  30  and the through hole  11  of the central wheel  10  are arranged such that when the spindles  33  are received within the through hole  11 , the central wheel  10  and the inner wheels  30  are fixedly secured with one another, in particular for simultaneous rotational movement about the axis L-L. On a face of the respective inner wheel  30  opposite the central wheel  10  is a respective outer wheel  20 . Each of the outer wheels  20  is thus also on a side of the central wheel  10 . An axle  32  of the inner wheel  30  is receivable within a longitudinal hole  22  of the respective outer wheel  20 , allowing free rotation of the outer wheel  20  relative to the respective inner wheel  30 , and thus relative to the central flint wheel  10 , about the axis L-L.  
         [0019]     A spring  40  is disposed over the axle  32  and between the inner wheel  30  and the outer wheel  20 , which biases the outer wheel  20  away from the respective inner wheel  30 . On a surface of the inner wheel  30  facing the respective outer wheel  20  are teeth  31  arranged in a ring shape, which are sized and configured to mesh with teeth  21 , also arranged in a ring shape, in a concave surface of the respective outer wheel  20 .  
         [0020]     The manner of operation of the flint wheel assembly  2  may be described more clearly with reference to  FIG. 4 . When the flint wheel assembly  2  is in the normal, stable configuration as shown in  FIG. 4 , the outer wheels  20  are out of contact with the inner wheel  30 , and thus the teeth  21  of the outer wheels  20  are out of mesh with the teeth  31  of the inner wheel  30 . As the diameter of the outer wheels  20  is larger than that of the flint wheel  10 , when a digit, e.g. a thumb, of a user acts on the assembly  2  with a view to rotating the flint wheel  10 , it will only act on the two outer wheels  20 . However, as the teeth  21  of the outer wheels  20  are out of mesh with the teeth  31  of the inner wheel  30 , rotation of the outer wheels  20  will not bring about corresponding rotation of the inner wheels  30 , and thus the central wheel  10 . Thus no spark will be generated, and no flame will be produced. The outer wheels  20  are shown here as having corrugations which enhance engagement between the user&#39;s thumb and the wheels  20 . It is, of course, possible to dispense with such corrugations, in order to enhance the child-resistance of the assembly  2 .  
         [0021]     In order to generate spark, at least one of the outer wheels  20  is pushed, e.g. by a thumb of a user applying an external force acting in the direction indicated by the arrow F, to move towards the central wheel  10 , along a path which is parallel to the longitudinal axis of the outer wheel  20 , against the biasing force of the spring  40 , such that the teeth  21  of the outer wheel  20  are in contact with and in mesh with the teeth  31  of the inner wheel  30 . It can be seen that the direction indicated by the arrow F is also parallel to the axis of rotation L-L of the assembly  2 . When the outer wheel  20  so engages the inner wheel  30 , and with the continuous application of the external force, rotation of the outer wheel  20  will bring about corresponding co-axial rotation of the inner wheel  30 , and thus the central wheel  10 , so as to rub against a flint to generate spark for producing a flame. Simultaneous rotation of the outer wheels  20  and the inner wheel  30  will only occur with the application of the external force. When the external force is released, the spring  40  will push the outer wheel  20  away from the inner wheel  30 , thus disengaging the outer wheel  20  from the inner wheel  30 , and thus from the central wheel  10 . It should also be noted that an external force acting on the outer wheel  20  in a radial direction will not bring about engagement between the outer wheel  20  and the inner wheel  30 .  
         [0022]     Apart from the teeth arrangement discussed above and shown in FIGS.  1  to  4 , the outer wheel and the inner wheel may be engaged with each other by a number of different arrangements. As shown in  FIG. 5 , a rough surface  121  on an outer wheel  120  may face and be engageable with a rough surface  131  of an inner wheel  130 . With the application of the external force urging the outer wheel  120  against the inner wheel  130 , the rotation of the outer wheel  120  will bring about simultaneous rotation of the inner wheel  130 .  
         [0023]     On the other hand, and as shown in  FIG. 6 , a rubber or similar soft material  250  may be fixed, e.g. by adhesion, to a surface  221  of an outer wheel  220 , or to a surface  231  of an inner wheel  230 , so as to enhance frictional engagement between the inner wheel  220  and the outer wheel  230 .  
         [0024]      FIG. 7  shows another possible arrangement which is similar to that shown in FIGS.  1  to  4 . In the arrangement shown in  FIG. 7 , on a surface of an outer wheel  320  facing a corresponding inner wheel  330  are provided with a set of slanted teeth  321 , which will only mesh with a set of slanted teeth  331  on a surface of the inner wheel  330  facing the outer wheel  320  when the outer wheel  320  is acted on by an external force.  
         [0025]     A further possible engagement arrangement is shown in  FIG. 8 , in which one or more protrusion  424  is provided on a surface of the outer wheel  420  facing an inner wheel  430 , whereas one or more recess or through hole  435  sized and configured to receive only part of the protrusion  424 , e.g. part of the free end of the protrusion  424 , is provided on the surface of the inner wheel  430  facing the inner wheel  420 . The protrusion  424  may be an arcuate protrusion or a spindle. Of course, such an arrangement will work equally well with the protrusion provided on the inner wheel  430  and the recess or through hole provided on the outer wheel  420 . As shown in  FIG. 8 , even when the outer wheel  420  is engaged with the inner wheel  430 , as they are only loosely engaged, rotational movement of the outer wheel  420  will only bring about corresponding rotational movement of the inner wheel  430  if there is an external force urging the outer wheel  420  against the inner wheel  430 .  
         [0026]     It should be noted that it is not strictly necessary to have the spring  40  in order for the assembly  2  to work. The spring  40  is only installed for further reducing the chance of accidental actuation of the central wheel  10  by a child.  FIG. 9  shows a flint wheel assembly according to a second preferred embodiment of the present invention, generally designated as  502 . The assembly  520  differs from the flint wheel assembly  2  discussed above only in that there is no spring between the respective outer wheel  520  and the inner wheel  530 . Even in the absence of any spring or similar means which biases the respective outer wheel  520  and inner wheel  530  away from each other, no simultaneous rotational movement between the respective outer wheel  520  and inner wheel  530  will occur even if the teeth  521  of the outer wheel  520  are in mesh with and in contact with the outer teeth  531  of the inner wheel  530 . Simultaneous rotational movement between the respective outer wheel  520  and inner wheel  530  will occur only if there is also a continuous force urging the outer wheel  520  against the inner wheel  530 .  
         [0027]     It should be understood that the above only illustrates examples whereby the present invention may be carried out, and that various modifications and/or alterations may be made thereto without departing from the spirit of the invention. For example, although the invention has so far been described and shown as having two outer wheels each on one side of the flint wheel, it is equally possible to have only one outer wheel operatively associated with the flint wheel.  
         [0028]     It should also be understood that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any appropriate sub-combinations.