Patent Publication Number: US-2004053179-A1

Title: Gas lighting rods

Description:
[0001] The present invention relates to gas lighting rods.  
       [0002] A gas lighting rod is a wand-like device used for lighting fires, comprising a source of gas and an operating member which, when manually pressed down, opens a gas flow path to the end of the device and, by means of a piezo-electric element, generates a spark for igniting the gas. The operating member is spring-loaded to return to its normal position after operation. Various examples are described, for example, in U.S. Pat. No. 5,697,775 (Tokai).  
       [0003] It is important to provide a safety mechanism, to reduce the chances of the device being operated by children. The standard safety technique is to provide a spring-loaded safety member which has to be operated before the operating member can be operated; the safety member can be moved transversely to the operating member to release the operating member. The operating member moves generally longitudinally along the axis of the lighting rod, and the safety member thus moves transversely to the axis of the lighting rod.  
       [0004] We have found that this relationship between the operating and safety members has significant disadvantages. The application of a high force on the operating member is liable to cause distortion of the safety member such that the operating member becomes freed and can therefore move and cause ignition. The spring force on the safety member needs to be limited in order to limit friction with the operating member; if the spring force is too high, when the safety member is released and the operating member is operated, the latter may be blocked in an intermediate position. Further, in such an intermediate state or position, the operating member may not return fully to its normal position, so holding the safety member in the release position; the operating member can then be operated without the safety member having to be operated first to release it.  
       [0005] According to the invention there is provided a gas lighting rod comprising a gas release valve and a piezo-electric lighting system both operated by a spring-loaded operating member, and a spring-loaded safety member which has to be operated to release the operating member, characterized in that the operating member is aligned transversely and the safety member comprises a pivoted lever having a lock/release arm extending generally along the axis of the operating member and interacting therewith and a control arm engaged on the other side of the pivot and from the opposite side of the lighting rod from the operating member.  
       [0006] The end of the lock/release arm is preferably sloped such that its engagement with the operating member tends to urge it into the locked position if the user attempts to operate the operating member without first fully operating the safety member. This arm is also preferably substantially enclosed within the operating member.  
       [0007] The spring force provided by the piezo spring may be enough to provide the required spring bias to the operating member so that an additional biasing spring for the operating member is not required.  
       [0008] This arrangement has various structural advantages. The fact that the lock/release arm is substantially enclosed within the operating member means that even under the application of an extremely high force on the operating member, the safety member will remain effective to restrain movement of the operating member. The spring force on the safety member can be adjusted within wide limits without resulting in undue friction with the operating member. Further, the system is virtually immune to the safety member taking up an intermediate state or position in which the operating member can be operated a second time without having to operate the safety member, as the safety member is biased from such a potential intermediate position towards the correct position.  
       [0009] The arrangement also has the functional advantage that it is particularly easy and comfortable to operate. It can readily be held in the hand in such a way that the user&#39;s thumb falls comfortably onto the operating member on one side of the lighting rod and their forefinger on the control arm of the safety member on the opposite side (or possibly vice versa). In contrast, in the prior art designs, the longitudinal arrangement of the operating member and the transverse arrangement of the safety member can make operation of the lighting rod awkward and inconvenient. 
     
    
    
     [0010] A lighting rod embodying the invention will now be described, by way of example, with reference to the drawings, in which:  
     [0011]FIG. 1 is a simplified view of the lighting rod from the side, with part of the casing removed, showing the normal state; and  
     [0012]FIGS. 2 and 3 are partial simplified views of two modifications of the lighting rod of FIG. 1. 
    
    
     [0013] Referring to FIG. 1, the main components of the lighting rod comprise an operating member  10 , a safety member  25 , a gas container  40 , a nozzle assembly  45 , and a casing  50 . Only those elements relevant for present purposes are shown, and in simplified form.  
     [0014] The casing  50  is of the clam-shell type, consisting of two half-shells which are broadly mirror images of each other and fit together by pin and socket elements around their meeting edges. The drawing shows the lighting rod with the front half-shell removed so that the rear half-shell  51  is visible. This casing holds the other components in place. In particular, it holds the gas bottle  40  at the right-hand end and the nozzle assembly  45  at the left-hand end.  
     [0015] The operating member  10  comprises a button  11  which has a bore  12  containing a piezo-electric mechanism comprising two elements  13 ,  14 . The button  11  is urged into the upwards position, ie the position shown, by a spring  15  which engages in a bore (not shown) in the button and against a stop  52  formed as part of the half-shell  51 . The piezo spring (not shown) also provides spring biasing force on the operating button  11 . In an alternative embodiment which is not shown it is possible to provide the operating button  11  without its own spring  15  but in a way which relies entirely on the biasing force of the piezo spring (not shown).  
     [0016] The button  11  can be manually depressed against the force of the spring  15 , and the piezo spring, moving the piezo-electric mechanism  13 - 14  downwards. A lever  19  is located as shown, pivoted on a pivot bearing  53  formed as part of the casing  50 . This lever  19  engages the valve  41  of the gas bottle  40 . Downward movement of the piezo-electric mechanism  13 - 14  rotates the lever  19  anti-clockwise, so operating the valve  41  and releasing a flow of gas from the bottle  40 . This gas flows to the end of the nozzle assembly  45 .  
     [0017] The movement of the piezo-electric mechanism  13 - 14  is limited by a stop  54  formed as part of the casing  50 . Further pressure on the button results in compression of the two elements  13  and  14  of the piezo-electric mechanism  13 - 14  together and the generation of a spark at the end of the nozzle assembly  45 . The compression of the piezo-electric elements occurs after the release of the gas flow, so the gas flow should have reached the end of the nozzle assembly by the time the spark is produced.  
     [0018] The safety member  25  (shown partly in section) consists of two arms, a lock/release arm  26  and a control arm  27 . These two arms are joined to form an L shape. The vertex  28  of the L forms a pivot which pivots in a pivot bearing  55  formed as part of the casing  50 . The safety member  25  is urged anti-clockwise by a spring  29 , which engages with the inside of the control arm  27  and bears against the stop  52  formed as part of the casing  50 . The outside of the control arm  27  is normally substantially flush with the casing  50 , as shown.  
     [0019] The lock/release arm  26  of the safety member  25  is contained within a bore  17  of the button  11 . This bore contains a projecting stop element  16  at its upper end, so that the bore  17  is wide in its lower part and narrow in its upper part. In the normal position of the safety member  25 , the top end  30  of the lock/release arm bears against this projecting element  16  as shown. As a result, the operating member is locked against movement. When the safety member is operated, however, by manual depression of the control arm  27 , the lock/release arm  26  rotates clockwise. This brings its upper end  30  out of engagement with the projecting element  16  in the button  11  and into alignment with the upper part of the bore  17 . As a result, the button  11  is released for movement; this button can therefore be depressed, with the lock/release arm  26  of the safety member  25  moving up in the upper part of the bore  17 .  
     [0020] The end  30  of the lock/release arm  26  of the safety member  25  is angled as shown, and the stop  16  in the bore  17  has a corresponding or greater angle. As a result, the button  11  can be depressed only if the safety catch has been fully operated. If the safety catch is not fully operated, ie if the end  30  of the lock/release arm  26  of the safety member  25  is not moved fully out of engagement with the stop  16 , then the slope on the end  30  of this arm and the angled surface of the stop  16  will result in any pressure on the button  11  tending to force the safety member back anti-clockwise into the locked position.  
     [0021] After the button  12  has been depressed, the safety button  25  can be released. The arm  26  will then move back anti-clockwise about the pivot  53 , with its end pressing lightly against the side of the bore  17 . When the button  10  is then released, this button will rise back to the position shown. The end of the arm  30  will slide along the side of the bore  17 , with relatively low friction, until it reaches the projecting element  16 , when it will jump back into the position shown.  
     [0022]FIG. 2 shows a modification of this arrangement; the same reference numerals are used for corresponding parts, with added “A”s where the parts have significantly different forms. A common type of piezo-electric mechanism  13 - 14  has a pair of projections  18  on one of the elements  13 - 14 . In the FIG. 2 arrangement, a piezo-electric mechanism of this form is used, with the projections  18  being oriented as shown. The lock-release arm  26 A of the safety member  25 A is arranged to engage with these projections  18  on the control rod  12  as shown.  
     [0023]FIG. 3 shows a further modification of the FIG. 1 arrangement, again with the same reference numerals and with added “B”s where the parts have significantly different forms. In this arrangement, the safety member is a lever  31 . This lever has a right-hand arm which is cranked to have an upward extension  26  which engages with the bore  17  and step  16  of the operating member  10  as before. The lever  31  is pivoted at  32 , and its left-hand arm extends horizontally beyond this pivot as shown. This safety member  31  is separate from the control or safety button  25 B, which has an extension at its left-hand end which engages with the left-hand end of the left-hand horizontal arm of the safety member.  
     [0024] The spring  15 B which engages with the control button  10  engages at its other end with a stop  52 B on the casing  50 . However, the spring  29 B operates between the safety button  25 B and the right-hand part of the safety member  31 .  
     [0025] It is obvious that the modifications of FIGS. 2 and 3 can both be applied simultaneously to the arrangement of FIG. 1. It will also be apparent to persons skilled in the art that other modifications to the described embodiments are possible whilst still including the essential elements of the invention as defined by the appended claims.