PIEZOELECTRIC LIGHTER EQUIPPED WITH A SAFETY LOCK

Abstract: Piezoelectric lighter equipped with a rotatable hook-shaped safety lock is composed of a shank, a finger catch fixed to one end of the shank, a pivot fixed to the other end of the shank, a catch plate fixed to the pivot at the side opposite to the shank and extending substantially perpendicularly to the shank, the catch plate having a longitudinal size larger than the width of the slot of a push cap which is put on a piezoelectric unit and a lateral size smaller than the width of the slot of the push cap. The safety lock is rotatable fixed to the top raised side of the casing at such a position that the catch plate may prevent the push cap from descending when the safety lock is put in its locking position in which the shank is vertical with the catch plate laid horizontal and at such a position that the catch plate may allow the push cap to descend when the safety lock is put in its unlocking position in which the shank is horizontal with the catch plate laid vertical.

Description: The present invention relates to a piezoelectric lighter in accordance with the preamble of claim 1. Such a lighter is known from FR-A-2295359. A conventional piezoelectric lighter is designed so that a thumb push to its operating cap may cause ejection of flamable gas from its nozzle and at the same time, appearance of spark across the gas from the nozzle, thereby causing a small flame to shoot upward. Such a lighter can be used even by a child, and therefore there is a fear that a fire may take place or the child may burn for instance, its hand while playing with the lighter. With this in mind, the object of the present invention is to provide a piezoelectric lighter equipped with a safety lock which is simple in structure and easy to use, still ensuring prevention of accidental fire or burn on one's body This problem is solved by the lighter in accordance with claim 1 comprising a casing, a gas ejection nozzle appearing from the ceiling of the casing; a windshield fixed to the ceiling of the casing and en­ circling the gas ejection nozzle, a piezoelectric unit fitted in the casing, a thumb-operated push cap operatively connected both to the gas ejection nozzle and to the piezoelectric unit for striking spark in response to a push to the push cap, and a liquefied gas cell defined in the casing and communicating with the gas ejection nozzle, is improved according to the present invention in that the thumb-operated push cap has a slot made on its outer surface and that it further comprises a rotatable hook-shaped safety lock, which is composed of a shank, a finger catch fixed to one end of the shank, a pivot fixed to the other end of the shank, a catch plate fixed to the pivot at the side opposite to the shank and extending substantially perpendicular to the shank, the catch plate having a longitudinal size larger than the width of the slot of the push cap and a lateral size smaller than the width of the slot of the push cap, the safety lock being rotatably fixed to the top raised side of the casing at such a position that the catch plate may prevent the push cap from descending when the safety lock is put in its locking position in which the shank is vertical with the catch plate laid horizontal and at such a position that the catch plate may allow the push cap to descend when the safety lock is put in its unlocking position in which the shank is horizontal with the catch plate laid vertical. In operation when the rotatable hook-shaped safety lock is rotated to the locking position in which its shank is vertical with its catch plate laid horizontal, thereby causing the slot of the push cap to prevent the push cap from descending to strike fire, whereas when the rotatable hook-shaped safety lock is rotated to the unlocking position in which its shank is horizontal with its catch plate laid vertical, thereby allowing the catch plate to slide in the slot of the push cap to allow the push cap to descend and strike fire. The present invention will be better understood from the following description of a piezoelectric lighter according to a preferred embodiment of the present invention, which is shown in accompanying drawings: Fig. 1 is a perspective view showing the top of a piezoelectric lighter according to a preferred embodiment of the present invention; Figs. 2 and 3 show how a safety lock is attached to the lighter body; Fig. 4 is a longitudinal section of the lighter; Fig. 5 shows schematically the position in which the ligh­ ter is locked; and Figs. 6 to 8 show schematically the position in which the lighter is unlocked. Referring to the drawings, a piezoelectric lighter accord­ ing to a preferred embodiment of the present invention is indi­ cated at "A". The piezoelectric type is shown as comprising a casing 1, a gas ejection nozzle 2 appearing from the ceiling of the casing, a windshield 3 fixed to the ceiling of the casing and encircling the gas ejection nozzle 2, a piezoelectric unit 8 fitted in the casing, a thumb-operated push cap 4 operatively connected both to the gas ejection nozzle and to the piezoelectric unit for striking spark in response to a push to the push cap, and a liquefied gas cell 5 defined in the casing and communication with the gas ejection nozzle. The liquified gas cell 5 is closed with its cap member 6, and a piezoelectric unit casing 7 with a raised top side is fitted in the cap member 6, and is connected to the casing 1. As shown, the piezoelectric unit 8 is fitted in the casing 7, exposing its top portion above the casing 7. The thumb-opetated push cap 4 is attached to the top of the piezoelectric unit 8. It is vertically movable, and is spring-biased upwards. When pushed down with thumb, the push cap 4 will be yeildingly lowered to subject the piezoelectric unit 8 to a strike for gen­ erating between its terminals 9 and 10 a voltage high enough to cause an electric spark in the vicinity of the gas ejecting nozzle 2. The push cap 4 has a slot 4a made on its outer surface. A rotatable hook-shaped safety lock 11 is composed of a shank 11a, a finger catch 111a fixed to one end of the shank, a pivot 11c fixed to the other end of the shank, a catch plate 11b fixed to the pivot at the side opposite to the shank 11a and extending substantially perpendicular to the shank 11a. The catch plate 11b has a longitudinal size larger than the width of the slot 4a of the push rod 4 and a lateral size smaller than the width of the slot 4a of the push rod. The safety lock 11 is rotatably fixed to the top raised side 7a of the casing. Specifically, the top raised side 7a has a V-and-circular shaped notch 71b and 7b at a position corresponding to the slot 4a of the push cap 4, as best seen from Fig. 2. The channel connecting the open pointed end of the V-notch 71b to the cir­ cular hole 7b is somewhat narrower than the diameter of the pivot 11c. When the pivot 11c is pushed in the channel, it yielding expands wide enough to allow the pivot 11c to snap in the circular hole 7b. When the pivot 11c has snapped in the circular hole 7b, the channel resiliently returns to its original size, thereby preventing the pivot 11c from slipping off from the circular hole. Thus, the hook-shaped safety lock 11 is rotatably fixed to the raised side of the piezoelectric unit casing with its catch plate 11b and shank 11a inside and out respectively. Preferably, a sector indentation 7c is made in the outer surface of the casing at a position which is contiguous to the V-and-­ circular hole 71b and 7b. The sector indentation 7c is deep enough for the shang 11a to be flush with the casing surface, thereby allowing the finger catch 111a of the safety lock 11 to appear on the casing surface. Two semispherical projections 7d are about 90 degrees apart from each other in the sector inden­ tation 7c, and the shank 11a of the safety lock 11 has a small semispherical blind hole, although not seen from the drawings. One of these projections 7d may snap in the blind hole of the shank 11a of the safety lock 11 when the safety lock 11 is put in its locking position in which the shank 11a is vertical with the catch plate 11b laid horizontal, thereby catching the slot 4a of the push cap 4 to prevent the push cap 4 from de­ scending (See Figs. 1 and 5) whereas the other projection may snap in the blind hole of the shank 11a of the safety lock 11 when the safety lock 11 is put in its unlocking position in which the shank is horizontal with the catch plate laid verti­ cal, thereby allowing the catch plate 11b to slide in the slot 4a of the push cap 4 to permit the push cap 4 to descend (See Figs. 6, 7 and 8). In the locking position the shank 11a is held vertical with its blind hole caught by the lower semispherical projection. Likewise, in its unlocking position the shank 11a is horizontal with its blind hole caught by the upper semispherical projec­ tion. The safety lock can be easily moved with thumb to select one of the two stable positions. It should be, however, noted that thanks to the gravity of the shank's weight, the selection of the vertical, locking position requires a force less than that which is required for selecting the horizontal, unlocking position. This and the natural, vertical posture of the shank of the safety lock in its locking position, together, would in­ crease the probability with which the lighter is put in its locking position, compared with the probability with which the lighter is put in its unlocking position. Thus, this arrange­ ment has an effect on prevention of accidental fire or burn on one's body, which would be caused by inadvertent unlocking of the lighter.

Claims: 1. A piezoelectric lighter comprising: a casing (1); a gas ejection nozzle (2) appearing from the ceiling of the casing; a windshield (3) fixed to the ceiling of the casing and encircling the gas ejec­ tion nozzle; a piezoelectric unit (8) fitted in the casing; a thumb-­ operated push cap (4) operatively connected both to the gas ejection nozzle and to the piezoelectric unit for striking spark in response to a push to the push cap; and a liquified gas cell (5) defined in the casing and communicating with the gas ejection nozzle, characterized in that the thumb-operated push cap (4) has a slot (4a) made on its outer surface and that it further comprises a rotatable hook-shaped safety lock (11), which is composed of a shank (11a), a finger catch (111a) fixed to one end of the shank, a pivot (11c) fixed to the other end of the shank, a catch plate (11b) fixed to the pivot at the side opposite to the shank and extending substantially per­ pendicular to the shank, the catch plate having a longitudinal size larger than the width of the slot of the push cap and a lateral size smaller than the width of the slot of the push cap, the safety lock (11) being rotatably fixed to the top raised side of the casing at such a position that the catch plate may prevent the push cap from descending when the safety lock is put in its locking position in which the shank is vertical with the catch plate laid horizontal and at such a position that the catch plate may allow the push cap to descend when the safety lock is put in its unlocking position in which the shank is horizontal with the catch plate laid vertical. 2. A piezoelectric lighter as claimed in Claim 1, wherein the casing has two small semispherical projections on its outer sur­ face, and the shank of the safety lock has a small blind hole, the two projections being positioned so that one of these projections may snap in the blind hole of the shank of the safety lock when the safety lock is put in its locking position and so that the other projection may snap in the blind hole of the shank of the safety lock when the safety lock is put in its unlocking position. 3. A piezoelectric lighter as claimed in Claim 2, wherein the casing has a notch made on the raised side of the casing for bearing the pivot of the safety lock, and a sector indentation made in its outer surface, the sector indentation being deep enough for the shank of the safety lock to be flush with the casing surface, allowing the finger catch of the safety lock to appear on the casing surface, the two projections being about 90 degrees apart from each other in the sector indentation.

Inventors: NITTA, TOMIO TOKAI CORPORATION, 2181-7
Applicants: TOKAI CORPORATION
Application year: 1988
Main classification: F23Q2
IPC codes: F23Q2