1. Field of the Invention
This invention relates to a safety device for a piezoelectric gas lighter, and more particularly to a safety device for a piezoelectric gas lighter which prevents depression of an actuator cap of the lighter to prevent inadvertent ignition while the gas lighter is not used.
2. Description of the Prior Art
The piezoelectric gas lighter has an actuator cap which is mounted on an upper part of the lighter body to be movable up and down, and when the actuator cap is depressed, fuel gas is discharged and an ignition mechanism is actuated to ignite the fuel gas. Though the gas lighter is a convenient tool which can easily be ignited by depression of the actuator cap, it is not preferable in view of safety that those who do not know proper use of the lighter like a child inadvertently ignites it.
Accordingly, there has been a demand for a so-called child resistant gas lighter which cannot be inadvertently ignited by children or the like.
There have been proposed various kinds of child resistant gas lighter. Most of the safety devices built in these child resistant gas lighter have a lock mechanism which prevents depression of the ignition lever and must be released to allow the ignition lever to be depressed. However, any type of the conventional child resistant gas lighter has drawbacks in use and is desired to be improved for practical use.
For example, any one of the safety devices as disclosed in Japanese Unexamined Utility Model Publication Nos. 62(1987)-180244, 62(1987)-180247 and 63(1988)-142562, and U.S. Pat. Nos. 4,859,172, 4,786,248 and 4,784,602 has a lock member which prevents depression of the ignition lever. The lock member is manually moved between a locking position and a releasing position, and the lock member remains in the releasing position and the safety device cannot function unless the lock member is manually returned to the locking position after it is moved to the releasing position and the gas lighter is ignited. That is, the lock mechanism must be operated again after it is released and the lighter is used. Otherwise, the lock mechanism cannot function. Thus there has been a demand for a further improved lock mechanism.
There has been proposed a safety device having a so-called auto-return function for automatically returning the lock member (which prevents depression of the ignition lever) to the locking position in response to the igniting operation of the gas lighter after movement of the lock member to the releasing position. For example, those disclosed in U.S. Pat. Nos. 5,002,482 and 3,898,031, and Japanese Unexamined Patent Publication No. 3(1991)-25215 have such an auto-return function. However, either of these safety devices has drawbacks for practical use that release of the lock mechanism involves a motion of a finger along an L-shaped path, which adversely affects ease of releasing the lock mechanism in the gas lighter which is generally operated with a single finger, e.g. the thumb, and leads to different results depending on persons who use the lighter. Further, in the safety device disclosed in the former patent publication, the lock member is formed of resilient material and accordingly, the lock member can return to the locking position under its own resiliency after it is moved to the releasing position.
Though there have been proposed safety devices in which the lock mechanism is released by a motion of a finger along a path in the form of a simple line. not L-shaped, any one of them has drawbacks for practical use. For example, in the safety device disclosed in Japanese Patent Publication of Translated Version (PCT) No. 3(1991)-501647, a part of a lock member which is formed of spring is moved along an arcuate path to the releasing position and held there. However, in the safety device, the arrangement for guiding release of the spring-like lock member is not satisfactory and accordingly the lock member cannot be steadily released, which adversely affects ease of releasing the lock mechanism in the gas lighter which is generally operated with a single finger, e.g. the thumb, and leads to different results depending on persons who use the lighter as in the preceding example. Further, since the lock member is formed of spring, the lock member can deform to cause failure of the lock mechanism after repeated use of the lighter.
In the safety device disclosed in U.S. Pat. No. 4,832,596, the lock member is moved along a linear path to the releasing position but it automatically returns to the locking position unless it is held with a finger other than the finger with which the ignition mechanism is actuated. Accordingly, in the safety device, the lock member cannot be steadily released, which adversely affects ease of releasing the lock mechanism in the gas lighter which is generally operated with a single finger, e.g. the thumb, and leads to different results depending on persons who use the lighter as in the preceding examples.
In order to overcome such problems, there has been proposed an auto-return safety device in which the lock member is moved along a linear path to the releasing position, thereby facilitating release of the lock mechanism, and at the same time, it can be held in the releasing position with the finger with which the ignition mechanism is actuated, without using another finger. However, the safety device also has drawbacks for practical use. That is, in the safety device disclosed in the Japanese Unexamined Utility Model Publication No. 1(1989)-178456, the lock member is incorporated in the ignition lever, which is actuated to ignite the lighter, so that the lock member can be moved to the releasing position with the thumb for operating the ignition lever, and the ignition lever is actuated with the thumb after the lock member is moved to the releasing position with the thumb. Thus in the safety device, release of the lock mechanism is facilitated. However, the safety device is disadvantageous in that when the ignition lever is actuated with the thumb after the lock member is moved to the releasing position with the same finger, the lock member can be inadvertently released from the thumb and can return to the locking position. Accordingly, also in the safety device, the lock member cannot be steadily released, which adversely affects ease of releasing the lock mechanism in the gas lighter which is generally operated with a single finger, e.g. the thumb, and leads to different results depending on persons who use the lighter as in the preceding examples.
As can be understood from the description above, any one of the conventional child resistant safety device has drawbacks for practical use, and accordingly there has been a demand for a child resistant safety device which has an enhanced safety and is easy to handle.