Utility lighter with safety mechanism

Abstract

A utility lighter includes a trigger adapted to simultaneously engage a fuel valve and piezo-electric element. A safety mechanism engages the trigger to prevent inadvertent ignition of the lighter or use of the lighter by a small child. The safety mechanism physically restricts movement of the trigger when engaged. The safety mechanism may be disengaged to allow the trigger to be activated. The safety mechanism may be released without extinguishing the flame and is re-engaged when the trigger is released.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to utility lighters, more particularly to utility lighters with safety mechanisms to prevent inadvertent ignition or ignition by a small child.

2. Description of the Prior Art

Utility lighters, i.e., lighters with an extension to separate the burner and the handle, have become ubiquitous in the modern household for a variety of reasons. The extension allows a user to safely and easily ignite a flame in otherwise difficult to reach areas, such as barbeque grills, pilot lights on gas appliances, and fire places. Moreover, the distance between the handle and the burner allows the lighter to be kept aflame for extended periods of time without burning the user—thus permitting the user to light, quickly and easily, a large number of candles, ignite several points in a pile of kindling, or otherwise maintain a flame as desired.

Despite their convenience, utility lighters, as with any flame producing device, can be unsafe if inadvertently ignited or operated by a small child. Consequently, many safety mechanisms have been developed to prevent inadvertent ignition of and/or to make it difficult for a small child to operate utility lighters. Typically such safety mechanisms comprise a combination of two switches or triggers that must be operated simultaneously or in sequence before the lighter can be ignited. In most cases, a safety switch is engaged by the user's thumb and a trigger is pulled by the user's index finger. The coordination required to ignite the lighter significantly reduces or eliminates the possibility of inadvertent or accidental ignition. Likewise, the required coordination is typically too complex for a small child, essentially rendering the lighter inoperable in a small child's hands.

For example, U.S. Pat. No. 6,318,992 to Sung (“Sung”) discloses a utility lighter having a safety switch that must be engaged before the trigger on the device may be activated to ignite the burner. When engaged, the safety switch of Sung simultaneously opens the outlet valve of a pressurized fuel container and disengages a lever that would otherwise block the travel of the trigger. When the fuel valve is opened, fuel travels through a tube to the burner. The user may then activate the trigger, which compresses a piezo-electric element that in turn generates an electrical charge. The electrical charge is discharged as a spark in the vicinity of the burner, thereby igniting the gas to generate the desired flame. One drawback of the Sung device is that unburnt fuel may be vented to the atmosphere merely by activating the safety switch (which opens the fuel valve), thus creating a potential safety hazard and wasting fuel. In other words, because the igniting spark is generated only when the trigger is activated, failure to pull the trigger once the safety switch is activated will result in fuel flowing through the burner and into the atmosphere. Another drawback of the Sung device is that the release of the safety switch will cut off the flow of fuel to the burner, thus extinguishing the flame. As a result, if the user wishes to maintain a flame for any length of time, the user must keep the safety switch engaged. As the safety switch is typically engaged by the user's thumb, preserving this position over the desired period of time may become uncomfortable or difficult.

In another example, U.S. Pat. No. 6,663,383 to Jon (“Jon”) discloses a utility lighter having a safety switch that must be engaged before the trigger on the device may be activated to ignite the burner. Unlike the Sung device, the trigger of the Jon device simultaneously activates a fuel valve and triggers a piezo-electric igniter. However, the safety switch operates by holding a blocking plate in place against one side of the piezo-electric igniter. Consequently, if the safety switch is not held in place by the user, the igniter cannot be compressed and no ignition will occur. Nonetheless, the trigger may still be activated, thus opening the fuel valve. Thus, similar to the Sung device, merely activating the trigger of the Jon device, without holding the safety switch in place, will allow un-burnt fuel to be vented to the atmosphere, creating a safety hazard and wasting fuel. Unlike the Sung device, however, the Jon device does allow the user to release the safety switch after ignition while still keeping the fuel valve open with the trigger which, because it is activated by the index finger, is more ergonomically efficient and thus more comfortable to the user.

U.S. Pat. No. 6,722,877 to Wang et al. (“Wang”) also discloses a utility lighter having a safety switch that must be engaged before the trigger on the device may be activated to ignite the burner. However, unlike the Sung device, the safety switch of the Wang device repositions an actuating member within the lighter—when the safety switch is depressed, activation of a trigger causes the actuating member to engage both a fuel valve and a piezo-electric igniter simultaneously. Consequently, fuel cannot be vented without being ignited, thus avoiding the waste and hazard associated with the venting of unburnt fuel. However, the use of an intervening actuating member increases the mechanical complexity of the lighter, thus increasing the complexity of manufacture and the possibility of component failure. In addition, the actuating member of the Wang device must slide across the base of the safety switch for the lighter to operate. The friction arising from this interaction can make the lighter undesirably difficult to operate or, conversely, require the use of components manufactured to higher tolerances to reduce friction. Furthermore, if the safety switch of the Wang device is released during use, the actuating member returns to the safety position, thereby closing the fuel valve and extinguishing the flame. Thus, like the Sung device, the safety switch must remain engaged if the flame is to be maintained. Because the safety switch is oriented such that it is activated by the thumb, maintaining the safety switch in the activated position may be uncomfortable to the user over prolonged periods of time.

Accordingly, it would be desirable to provide a safety mechanism for a utility lighter that prevents inadvertent ignition. It also would be desirable to provide a safety mechanism for a utility lighter that renders the lighter difficult or impossible for a small child to operate. It also would be desirable to provide a safety mechanism for a utility lighter that prevents the venting of unburnt fuel to the atmosphere. It also would be desirable to provide a safety mechanism for a utility lighter that is ergonomically efficient, allowing a user to maintain a flame for a prolonged period of time with little or no physical discomfort. It would also be desirable to provide a safety mechanism for a utility lighter that is simple to manufacture and reliable in use.

SUMMARY OF THE INVENTION

A utility lighter according to the present invention includes a housing and a fuel container disposed within the housing. A fuel lever is affixed within the housing and engages a fuel valve to allow fuel to be delivered from the fuel container to a burner. A piezo-electric element is affixed within the housing and a trigger, which is slidably mounted to the housing, is adapted to simultaneously engage the fuel lever and the piezo-electric element.

A safety mechanism is provided to prevent the inadvertent ignition of the lighter or operation of the lighter by a small child. The safety mechanism includes a safety switch slidably mounted on the housing and a safety lever pivotally disposed within the housing. The safety lever is positioned between and adapted to engage the safety switch and selectively engage the trigger. Thus, in order to operate the trigger (thereby opening the fuel valve and generating a spark from the piezo-electric element), the safety switch must first be released. In addition, the safety lever is adapted to allow the safety switch to be released without extinguishing the flame, thus allowing a flame to be comfortably maintained by the user so long as the trigger is held in the engaged position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-sectional side view of a utility lighter according to the present invention.

FIG. 2 shows a partial cross-sectional side view of the trigger mechanism of the utility lighter of FIG. 1 in a first operational state.

FIG. 3 shows a partial cross-sectional side view of the trigger mechanism of the utility lighter of FIG. 1 in a second operational state.

FIG. 4 shows a partial cross-sectional side view of the trigger mechanism of the utility lighter of FIG. 1 in a third operational state.

FIG. 5 shows a cross-sectional side view of an alternate embodiment of a utility lighter according to the present invention.

FIG. 6 shows a partial cross-sectional side view of the trigger mechanism of the utility lighter of FIG. 5 in a first operational state.

FIG. 7 shows a partial cross-sectional side view of the trigger mechanism of the utility lighter of FIG. 5 in a second operational state.

FIG. 8 shows a partial cross-sectional side view of the trigger mechanism of the utility lighter of FIG. 5 in a third operational state.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-4, a utility lighter 10 according to the present invention comprises a housing 12 and a lighter tube 14. The housing 12 contains a trigger 24, a safety switch 26, a fuel container 28, a fuel valve 30, a piezo-electric element 32, a safety latch 34, and a fuel lever 36. The lighter tube 14 contains an ignition mechanism 16, a burner 18, a gas flow tube 20 and ignition wires 22.

Certain components of the lighter 10, specifically the fuel container 28, the fuel valve 30 and the piezo-electric element 32 are well-known in the art. Accordingly, those of ordinary skill in the art will recognize that such components may be selected as desired and suited for the particular design to be employed in the practice of the present invention. Other components of the lighter 10, such as the housing 12, the trigger 24, the safety switch 26, the safety latch 34, and the fuel lever 36 are preferably fabricated with a material having sufficient stiffness to permit operation of the lighter 10 without undue flexure. Suitable materials are familiar to those of ordinary skill in the art and may be selected accordingly.

The housing 12 may be formed to provide a “pistol”-like form or any other ergonomically desirable shape. The housing 12 includes a stop 38 to position and support the piezo-electric element 32, and a safety latch pivot 42 to engage the safety latch 34. The internal features may be integrally formed from the material of the housing 12 or otherwise affixed within the housing.

Referring to FIG. 4, the trigger 24 is positioned within the housing 12 so as to allow the trigger 24 to slide back and forth within the housing 12, as indicated by arrow 60.

The piezo-electric element 32 is positioned and secured within the housing 12 and between the stop 38 and the trigger 24. The piezo-electric element 32 is positioned such that when the trigger 24 is pulled or drawn towards the peizo-electric element 32 in the direction indicated by arrow 60, the piezo-electric element 32 is sandwiched between the stop 38 and the trigger 24, thereby activating the spring-loaded mechanism of the piezo-electric element 32. Upon activation, the piezo-electric element 32 generates a brief high-voltage electrical charge that is discharged through the ignition wires 22 and to the ignition mechanism 16 at the burner 18. When the trigger 24 is released, the spring-loaded mechanism of the piezo-electric element 32 urges the trigger 24 into its original position.

The fuel container 28 is positioned and secured within the housing 12. The fuel valve 30 is affixed to the fuel container 28 such that it is positioned proximate to the trigger 24. The fuel valve 30 may include a flame height adjuster 31, which may be rotated by means of an adjustment lever 33 to allow the user to vary the flow of fuel emanating from the lighter 10 and, hence, the intensity of the flame provided by the lighter 10.

The fuel lever 36 is positioned so as to engage the fuel valve 30 and the trigger 24, such that when the trigger 24 is pulled in the direction indicated by arrow 60, the lever 36 rotates as indicated by arrows 66A and 66B, pulling the fuel valve 30 forward (i.e., in the opposite direction of the motion of the trigger 24), and opening the valve 30. Upon opening of the valve 30, fuel flows through the gas flow tube 20 to the burner 18.

Thus, it can be seen that activation of the trigger 24 acts to simultaneously open the fuel valve 30 and operate the piezo-electric element 32. In this manner, fuel is released only in the presence of the spark generated by the piezo-electric element 32, ensuring that the fuel will be ignited and substantially reducing or eliminating the risk of venting unburnt fuel to the atmosphere. Moreover, when the trigger 24 is released, the trigger 24 is urged back into the “off” position by the piezo-electric element 32, as described above, which also has the effect of closing the fuel valve 30.

Referring to FIGS. 2 and 3, the safety switch 26 is positioned on and protrudes through the housing 12. The safety switch 26 is preferably located proximate to and on the opposite side of the lighter 10 from the trigger 24 to allow the user's thumb to be used to activate the safety switch 26 (by urging the switch 26 in the direction indicated by arrow 62) prior to or simultaneously activating the trigger 24 with the index finger. A spring 27 is positioned within the safety switch 26 and engages the housing 12 to urge the safety switch 26 back into its original position when released.

The safety latch 34 is positioned within the housing 12 and is mounted on the safety lever pivot 42. A spring 44 biases the latch 34 in the desired position locked position. The latch 34 is positioned to engage the safety switch 26 and the trigger 24 such that when the safety switch 26 is engaged by the user in the direction indicated by arrow 62, the latch 34 is rotated about the pivot 42 in the direction indicated by arrow 64 and disengaged from the trigger 24, thereby allowing the trigger 24 to be operated in the manner described above. When the safety switch 26 is not engaged, the spring 44 biases the latch 34 such that the latch is rotated downward into the trigger 24 and a catch 48 on the latch 34 engages a corresponding catch 49 on the trigger 24, fixing the trigger 24 in place. In short, release of the safety latch 34 acts only to release the trigger 24 and does not open fuel valve 30 or activate piezoelectric element 32. Thus, unlike safety mechanisms of the prior art, activation of the safety switch of the present invention does not permit the release of unburnt fuel. Moreover, because the activation of the trigger 24 (which is only possible when the safety switch 26 has been activated) simultaneously opens the fuel valve 30 and triggers the piezo-electric element 32, igniting the flame, the flame is ignited by the activation of the trigger, preventing the release of unburnt gas.

In addition, the safety switch 26 may be released once the flame is ignited without extinguishing the flame. This is because the release of the safety switch 26 releases the latch 34, which is then urged against the top of the trigger 24 (as shown in ghosted lines in FIG. 4) by the spring 44. The latch 34 does not interfere with the flow of fuel or otherwise inhibit the flow of fuel. This allows the user to release the safety switch 26 and employ only the user's index finger to maintain a flame, a more comfortable and ergonomically efficient position for the user's hand. Once the trigger 24 is released, it is urged into the “off” position by the piezo-electric element 32. As the trigger 24 returns to the “off” position, the latch 34 is urged against the trigger 24 and re-engages catch 49 to lock the trigger 24 in place.

Referring to FIGS. 5-8, an alternative embodiment of a utility lighter 110 according to the present invention comprises a housing 112 and a lighter tube 114. The housing 112 contains a trigger 124, a safety switch 126, a fuel container 128, a fuel valve 130, a piezo-electric element 132, a safety latch 134, and a fuel lever 136. The lighter tube 114 contains an ignition mechanism 116, a burner 118, a gas flow tube 120 and ignition wires 122.

Certain components of the lighter 110, specifically the fuel container 128, the fuel valve 130 and the piezo-electric element 132 are well-known in the art. Accordingly, those of ordinary skill in the art will recognize that such components may be selected as desired and suited for the particular design to be employed in the practice of the present invention. Other components of the lighter 110, such as the housing 112, the trigger 124, the safety switch 126, the safety latch 134, and the fuel lever 136 are preferably fabricated with a material having sufficient stiffness to permit operation of the lighter 110 without undue flexure. Suitable materials are familiar to those of ordinary skill in the art and may be selected accordingly.

The housing 112 may be formed to provide a “pistol”-like form or any other ergonomically desirable shape. The housing 112 includes a stop 138 to position and support the piezo-electric element, a fuel lever pivot 140 to engage the fuel lever 136, and a safety latch pivot 142 to engage the safety latch 134. The internal features may be integrally formed from the material of the housing 112 or otherwise affixed within the housing.

Referring to FIG. 8, the trigger 124 is positioned within in the housing 112 so as to allow the trigger 124 to slide back and forth within the housing 112, as indicated by arrow 160.

The piezo-electric element 132 is positioned and secured within the housing 112 and between the stop 138 and the trigger 124. The piezo-electric element 132 is positioned such that when the trigger 124 is pulled or drawn towards the piezo-electric element 132 in the direction indicated by arrow 160, the piezo-electric element 132 is sandwiched between the stop 138 and the trigger 124, thereby activating the spring-loaded mechanism of the piezo-electric element 132. Upon activation, the piezo-electric element generates a brief high-voltage electrical charge that is discharged through the ignition wires 122 and to the ignition mechanism 116 at the burner 118. When the trigger 124 is released, the spring-loaded mechanism of the piezo-electric element 132 urges the trigger 124 into its original position.

The fuel container 128 is positioned and secured within the housing 112. The fuel valve 130 is affixed to the fuel container 128 such that it is positioned proximate to the trigger 124. The fuel valve 130 may include a flame height adjuster 131, which may be rotated by means of an adjustment lever 133 to allow the user to vary the flow of fuel emanating from the lighter 110 and, hence, the intensity of the flame provided by the lighter 110. The fuel lever 136 is positioned so as to engage the fuel valve 130, the fuel lever pivot 140, and the trigger 124, such that when the trigger 124 is pulled in the direction indicated by arrow 160, the lever 136 rotates around the pivot 140 as indicated by arrows 166A and 166B, pulling the fuel valve 130 forward (i.e., in the opposite direction of the motion of the trigger 124), and opening the valve 130. Upon opening of the valve 130, fuel flows through the gas flow tube 120 to the burner 118. Notably, the fuel lever 136 may comprise a yoke-shaped lever straddling the piezo-electric element 132. In this manner, the fuel lever 136 may contact and engage the trigger 124 in a region proximate to where the piezo-electric element 132 engages the trigger. Consequently, the force required to activate the trigger 124 and ignite lighter 110 may be concentrated in the same region of the trigger. It has been found that this arrangement permits the trigger 124 to be operated smoothly and efficiently with little excess effort or discomfort to the user.

Thus, it can be seen that activation of the trigger 124 acts to simultaneously open the fuel valve 130 and operate the piezo-electric element 132. In this manner, fuel is released only in the presence of the spark generated by the piezo-electric element 132, ensuring that the fuel will be ignited and substantially reducing or eliminating the risk of venting unburnt fuel to the atmosphere.

Referring to FIGS. 6 and 7, the safety switch 126 is positioned on and protrudes through the housing 112. The safety switch 126 is preferably located proximate to and on the opposite side of the lighter 110 from the trigger 124 to allow the user's thumb to be used to activate the safety switch 126 (by urging the switch 126 in the direction indicated by arrow 162) prior to or simultaneously activating the trigger 124 with the index finger. A spring 127 is positioned within the safety switch 126 and engages the housing 112 to urge the safety switch 126 back into its original position when released.

The safety latch 134 is positioned within the housing 112 and is mounted on the safety lever pivot 142. A spring 144 biases the latch 134 in the desired position locked position. The latch 134 is positioned to engage the safety switch 126 and the trigger 124 such that when the safety switch 126 is engaged by the user in the direction indicated by arrow 162, the latch 134 is rotated about the pivot 142 in the direction indicated by arrow 164 and disengaged from the trigger 124, thereby allowing the trigger 124 to be operated in the manner described above. When the safety switch 126 is not engaged, the spring 144 biases the latch 134 such that the latch is rotated downward into the trigger 124 and a catch 148 on the latch 134 engages a corresponding catch 149 on the trigger 124, fixing the trigger 124 in place. In short, release of the safety latch 134 acts only to release the trigger 124 and does not open fuel valve 130 or activate piezo-electric element 132. Thus, unlike safety mechanisms of the prior art, activation of the safety switch of the present invention does not permit the release of unburnt fuel. Moreover, because the activation of the trigger 124 (which is only possible when the safety switch 126 has been activated) simultaneously opens the fuel valve 130 and triggers the piezo-electric element 132, igniting the flame, the flame is ignited by the activation of the trigger, preventing the release of unburnt gas.

In addition, the safety switch 126 may be released once the flame is ignited without extinguishing the flame. This is because the release of the safety switch 126 releases the latch 134, which is then urged against the top of the trigger 124 (as shown in ghosted lines in FIG. 8) by the spring 144. The latch 134 does not interfere with the flow of fuel or otherwise inhibit the flow of fuel. This allows the user to release the safety switch 126 and employ only the user's index finger to maintain a flame, a more comfortable and ergonomically efficient position for the user's hand. Once the trigger 124 is released, it is urged into the “off” position by the piezo-electric element 132. As the trigger 124 returns to the “off” position, the latch 134 is urged against the trigger 124 and re-engages catch 149 to lock the trigger 124 in place.

It is also to be appreciated that the foregoing description of the invention has been presented for purposes of illustration and explanation and is not intended to limit the invention to the precise manner of practice herein. It is to be appreciated therefore, that changes may be made by those skilled in the art without departing from the spirit of the invention and that the scope of the invention should be interpreted with respect to the following claims.

Claims

1. A safety mechanism for a utility lighter comprising:

a housing;

a fuel tank having a fuel valve wherein the fuel tank is disposed within the housing;

a fuel lever pivotally disposed within the housing and engaging the fuel valve;

a piezo-electric element affixed within the housing;

a trigger slidably mounted to the housing and adapted to substantially simultaneously engage the fuel lever and the piezo-electric element;

a safety switch slidably mounted on the housing; and

a safety latch pivotally disposed within the housing and adapted to engage the safety switch and selectively engage the trigger.

2. The safety mechanism of claim 1 further comprising:

a flame height adjuster affixed to the fuel valve.

3. The safety mechanism of claim 1, wherein a portion of the fuel lever straddles the piezo-electric element.

4. The safety mechanism of claim 1 further comprising:

a spring affixed to and engaging the safety latch.

5. The safety mechanism of claim 4, wherein the spring biases the safety lever against the trigger.

6. The safety mechanism of claim 1, wherein the trigger includes a trigger catch.

7. The safety mechanism of claim 6, wherein the safety latch includes a safety catch.

8. The safety mechanism of claim 7, wherein the safety catch is adapted to engage the trigger catch when the trigger is in an unactivated position.

9. The safety mechanism of claim 7, wherein the safety catch is adapted to disengage from the trigger catch when the safety switch is urged into an activated position.

10. The safety mechanism of claim 7, wherein the safety catch is adapted to rest against an upper surface of the trigger when the trigger is urged into an activated position and the safety switch is urged into an unactivated position.

11. A utility lighter comprising:

a housing;

a fuel tank disposed within the housing, the fuel tank having a fuel valve;

a trigger slidably mounted to the housing and adapted to slide between a disengaged position and an engaged position, the trigger having a trigger catch and an upper surface adjacent to the trigger catch;

a fuel lever pivotally mounted within the housing, the fuel lever having a first end adapted to engage the fuel valve and a second end adapted to engage the trigger, wherein the fuel lever is adapted to urge the fuel valve into an open position when the trigger is in the engaged position and to allow the fuel valve to adopt a closed position when the trigger is in the disengaged position;

a piezo-electric element affixed within the housing, wherein the piezo-electric element is adapted to engage the trigger such that, as the trigger moves from the disengaged position to the engaged position, the piezo-electric element is compressed;

a safety latch pivotally mounted within the housing, the safety latch having a safety catch;

a safety switch slidably mounted to the housing and engaging the safety latch, wherein the safety switch is adapted to slide between an off position and an on position; and

a spring disposed within the housing and engaging the safety latch wherein the safety latch is positioned such that the safety catch engages the trigger catch when the safety switch is in the off position;

the safety latch being positioned such that the safety catch is disengaged from the trigger catch when safety switch is in the on position;

wherein the spring is adapted to bias the safety latch against the upper surface of the trigger when the safety switch is moved from the on position to the off position and the trigger is in the engaged position.

12. The utility lighter of claim 11 wherein the trigger is adapted to substantially simultaneously engage the fuel lever and the piezo-electric element.

13. The utility lighter of claim 11 wherein a portion of the fuel lever straddles the piezo electric element.

14. The safety mechanism of claim 11, further comprising a flame height adjuster affixed to the fuel valve.

15. The utility lighter of claim 11 wherein the piezo-electric element is adapted to urge the trigger from the engaged position to the disengaged position.