US 3829737 A
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United States Patent 1191 .lohnsson Aug. 13, 1974 PKEZO-ELECTRIC LIGHTERS Primary ExaminerVolodymyr Y. Mayewsky  Inventor: Lars Berti] Johnsson, Jonkoping, g g Agent or Flrm Kar] ROSS; Herbert Sweden u no  Assignee: Societe Anonyme GENOUD 8: CIE,  ABSTRACT Venissieux (Rhone), France  Fil d; J ly 18, 1973 fin upwardlybopen louter caslling, cgntainicriig a pies?- e ectrlc mem er, te escoplca y gui es a ownwar y [211 App! 380,292 open inner casing serving as an actuator for an igni-  Foreign Application Priority Data tion mechanism. The walls of the two casings are July 28 1972 France ..72.27950 formed with Partly registering Slots terminating in P- positely sloping lower camming edges, the outer slot 521 11.5. C1 317/81 317/1310. 11 310/87 being Provided at the uPPer and its camming edge 431/255" with a notch normally receiving a lug on a cylindrical 51 int. c1. F23q 13/00 F23q 3/01 Striker axially Slidable the prismatiC Casings-  Field of Search 317/81 DIG i 310/83 Upon depression of the inner casing against the force 6 4317132 of a spring bearing upon the striker, a beveled upper edge of the inner roove cams the lu out of the notch  References Cited whereupon the spring dr1ves the striker 1nto collis1on with the piezo-electric member. Upon the subsequent UNITED STATES PATENTS release of the actuator constituted by the inner casing, M1tune CI 11]. the two lower Camming edges coact to return the lug :7 5: to its notch as the striker is restored by the spring to 3I7Z9I63Z) 4 1973 Hcinoiichi:..::. .II... 1:. 310/83 3,734,680 5/1973 Maruyama 43l/l32 3,741,714 6/1973 Yosinaga 431/255 7 Claims, 6 Drawing Figures PATENTED AUG 1 31974 SHEET 2 BF 2 I PIEZO-ELECTRIC LIGHTERS FIELD OF THE INVENTION My present invention relates to an impacting mechanism for a lighter in which ignition is caused by the collision of a striker with a piezo-electric member.
BACKGROUND OF THE INVENTION Conventional ignition mechanisms of the directpercussion type use at least two springs (sometimes three or even four), i.e. a main spring which drives the striker and a return spring which restores the mechanism to its initial position when the pressure exerted on the main spring is released.
OBJECTS OF THE INVENTION SUMMARY OF THE INVENTION An impacting mechanism according to my invention comprises a downwardly open first casing and an upwardly open second casing engaging each other telescopically so as to be relatively slidable; relative rotation of the casings is prevented by suitable means, specifically by their prismatic shape. The two casings have wall portions respectively provided with first and a second slot (each duplicated on opposite sides of its casing) which partly register with each other in all operating positions.
The second casing, which in the embodiment described hereinafter is the outer one, contains a piezoelectric member forming part of an ignition circuit; an advantageously cylindrical striker is mounted above the piezo-electric member so as to be slidable inthe two casings, this striker having a transverse retaining lug in the form of a round pin traversing the registering wall slots. A compression spring inserted in the first (inner) casing bears upwardly against the latter and downwardly upon the striker for urging same toward the piezo-electric member.
In accordance with an important feature of my invention, the first (inner) wall slot has a first lower camming edge intersecting an oppositely inclined second lower camming edge of the second (outer) slot sloping downwardly from a lateral indexing notch normally receiving the lug of the striker. The two intersecting edges form a downwardly pointing vertex which shifts laterally away from the indexing notch upon depression of the first casing serving as an actuator. The first slot, formed in the actuator, also has an upper camming edge which is engageable with the lug in the course of a depression stroke and, upon an initial compression of the inserted spring, dislodges the lug from the indexing notch to enable that spring to expand whereby the striker is propelled against the piezo-electric member as its lug rides down the second, stationary, lower camming edge. Upon the subsequent release of the actuator, the lug is intercepted by the moving first lower camming edge and is cradled in the vertex of the two camming edges whereby a component of the spring pressure is absorbed by the stationary second edge. This enables the spring to exert an upward force upon the actuator, relative to the second casing, for restoring same to normal as the lug is returned to its indexing notch by the rising and laterally shifting vertex.
According to another feature of my invention, the wall slots of the two casings may be formed with access passages to facilitate the insertion of the lug.
BRIEF DESCRIPTION OF THE DRAWING The above and other features of my invention will now be described with reference to the accompanying drawing in which:
FIG. 1 is an axial sectional view of a conventional impacting mechanism for a lighter;
FIG. 2 is a view similar to FIG. 1, showing my present improvement;
FIG. 3 is a detail view of a retaining lug and associated camming slots forming part of the mechanism of FIG. 2;
FIG. 4 is a diagrammatic illustration of the lug and part of its camming edges, drawn to an enlarged scale;
FIG. 5 is an exploded perspective view of a slightly modified lighter according to my invention, showing its various constituent parts before assembly; and
- FIG. 6 shows the elements of FIG. 5 on a smaller scale and after assembly.
SPECIFIC DESCRIPTION In FIG. 1 I have shown, for purposes of comparison, a known lighter comprising an inner casing l, operating as a pushbutton-type actuator, with a slot 2' dupli cated on opposite sides thereof, forming an upper camming edge 2a. An outer casing 3 has a slot 4' also duplicated on its opposite sides and forming a retaining or indexing notch 4a. A striker 5, provided with a transverse lug 6 moving in the slots 2' and 4, is loaded by a main spring 7 bearing from within upon the stop of the inner casing 1 and exerting pressure on the striker 5, the casing being urged upwardly by a return spring 8. Striker 5' confronts an anvil 9' constituted by a piezo-electric member. An ignition circuit controlled by this member has been partly shown at 16.
When pressure is applied to the top of actuator 1', the main spring 7 is compressed until the lug 6 is cammed aside by the bevel or ramp 2a of slot 2 thereof. When this lug is disengaged from the notch 4a of the slot 4' of casing 3, the striker 5' strikes the piezo-electric member 9'. When the actuator l is released, the heretofore compressed return spring 8 expands and restores the mechanism to its initial position. Relatching of the lug in notch 4a'is insured by a twisting of the main spring 8 by about a three-quarter turn. The polygonal cross-sections of the inner and outer casings l, 3' prevent any relative rotation thereof.
Although such a device is simple, efficient and compact, its mechanism has several drawbacks.
Aside from the need for two springs, the return spring 8 opposes the finger pressure exerted by the user on the actuator 1' without contributing to the acceleration of the striker. Moreover, there is no automatic decrease in the counteracting force of this spring since the latter is fully compressed when the striker is released. For the same reason, the finger pressure applied to overcome this spring force cannot be used for driving the striker.
On the other hand, the torsion of the main spring 7' presses the lug 6' against the edge of the slot 4' of the outer casing 3' with considerable force during both the percussion stroke and the return stroke, thus opposing the movement of the striker by frictional resistance.
In FIGS. 2 6, parts corresponding to those of FIG. 1 have been designated by the same reference numerals, namely: the inner casing or actuator l with its slot 2 duplicated on opposite side thereof and forming a release ramp or bevel 2a the outer casing 3 with its slot 4 also duplicated on opposite sides and forming a retaining notch 4a, the striker 5 with its pin or lug 6, the percussion spring 7 and the piezo-electric anvil 9.
According to the invention, slot 2 has an inclined lower camming edge 11. The same is true for a camming edge 12 of slot 4 these two edges having relatively inverted slopes and intersecting at a vortex which progressively shifts to one side (here to the right) upon depression of the actuator. In the off-normal position of lug 6; the edges ll, 12 bear tangentially thereon, as best seen in FIG. 4, whereby the lug is cradled in their vertex.
This mechanism operates as follows:
When pressure is applied to the top of the actuator l, the spring 7 is compressed. Eventually, lug 6 is cammed aside by the ramp 2a of the slot 2 and the striker 5 collides with the piezo-electric member 9. During this movement, the lug 6 moves along the edge 12 (FIG. 3) of the slot 4 of the outer casing 3. One could thus expect a certain friction between the lug against this edge and likewise between the spring 7 and the striker 5. Nevertheless, the effects of this friction are slight since the force exerted on the lug by the ramp 2a of. the inner casing imparts a rotational movement to the striker from the beginning of its percussion action. This movement being continued by the camming action of edge 12 during the remainder of the stroke.
On the other hand, as the force of the spring decreases in proportion to the percussion stroke, the force exerted by the operators finger on the top of the inner casing l pushes the latter down, which increases the speed of the striker. At the same time, the reaction force encountered by the operators finger decreases progressively which makes the control of the apparatus much more pleasant.
When the percussion stroke is terminated, the spring 7 still remains compressed to a certain extent, of the order of 30 percent. This spring thus expands when the action of the pressure exerted on the inner casing by the actuators finger ceases, the lug 6 being then located at the lower end of the slot 4. At the same time, this lug 6 is in contact with the lower part of the righthand edge of the slot 2. During the initial part of the upward movement of the inner casing l, the lug 6 slides along this right'hand slot edge until it comes into contact with both the inclined edge 11 of the slot 2 and the intersecting edge 12 of the slot 4 (FIG. 3). Owing to the inclination of the edges 11 and 12, part of the force of the spring 7 is transferred from the edge 11 to the edge 12 so that this spring, which is interposed between the upper part of the inner casing l and the striker 5, may exert an upwardly directed independent force on the casing or actuator l. The actuator 1 thus begins to rise under the action of this independent force provided that the latter is greater than the frictional resistances which tend to oppose the relative movements between the various parts, namely:
a. the frictional force between the lug 6 and the edge 11 of the slot 2;
b. the frictional resistance between the lug 6 and the edge 12 of the slot 4;
c. the frictional resistance between the inner casing l and the outer casing 3; and
d. the frictional resistance between the spring 7 and the striker 5 and/or the upper part of the inner casing 1.
During the ascending movement of the inner casing I, the lug 6 slides down along the slot edge I1 and up along slot edge 12 until, with a rotary motion about the axis of the cylindrical striker, it engages in the notch 4a of the outer slot 4.
The reaction forces of the lug 6 on the edges 11 and 12 tend to rotate the inner casing 1 relative to the outer casing 3 which produces the frictional resistance (c). In addition, since the striker 5 rotates when the lug 6 slides along the edges 11 and 12, the spring 7 in turn twists with respect to the inner casing 1 and/or to the striker 5, thereby causing the relatively small frictional resistance d).
The condition that the net force above described be greater than the frictional forces a) d) sets restrictions on the angles of inclination a and B which the edges 11 and 12 respectively include with the horizontal (FIG. 4). In fact, it can be shown that the following conditions must be satisfied for the angles a and ,B:
a arctan }L(6,12) arctan p.(1,3) (1) and B arctan p.(6,ll) arctan .L(7,l) (2) where p.(6,l2) is the coefficient of friction between the lug 6 and the edge 12,
;/.(1,3) is that between the casings 1 and 3;
p.(6,1l) is that between the lug 6 and the edge 11,
p.(7,1) is that between the spring 7 and the part (the casing l or the striker 5) with respect to which the spring rotates.
It is difficult to make angles a and ,8 less than 20 and greater than 50. In the preferred embodiment, the angle a is greater than the angle [3, ranging for example between 25 and 40-45, whereas the value of the angle [3 may range for example between 25 and 35-40.
Naturally, and as is apparent from the preceding discussion, my invention is not limited to the single embodiment given herein above. Thus, for example, the function of the inner casing could be transferred to the outer casing and that of the outer casing to the inner casing.
According to the particular embodiment of FIGS. 5 and 6, the slot 2 is cut open at the top of its sloping edge 11 in order to provide a free passage 13 directed toward the bottom of the inner casing.
Similarly, the slot 4 is cut open at its upper right hand to provide a free passage 14 open toward the top of the outer casing, this passage being bounded by an inclined guide edge 15 overlying the notch 4a.
Under these conditions, the assembly of the various parts take place very simply and virtually automatically.
In fact, it is sufficient to:
1. insert the lug 6 into a hole of the striker 5,
2. introduce the spring 7 into the inner casing l,
3. introduce the striker 5 into this inner casing by inserting the lug 6 through the access passage 13; the tension thus imparted to the spring 7, upon relaxation of the external insertion pressure released, causes the lug to be automatically retained in the lower part of the slot 2 without being able to be accidentally released therefrom, and
4. thereupon insert the inner casing l with striker 5 and spring 7 into the outer casing 3 whereby the ramp 15 imparts a rotation to the lug 6 until the moment when, on clearing the access passage 14 above the level of indexing notch 4a, it snaps into that notch as shown in FIG. 6.
1. An impacting mechanism for the ignition of a lighter, comprising:
a downwardly open first casing;
1 an upwardly open second casing telescopically engaging said first casing and nonrotatably slidable with reference thereto, said first and second casings having wall portions respectively provided with first and second slots partly registering with each other in all operating positions;
an ignition circuit including a piezo-electric member on the bottom of said second casing;
a cylindrical striker rotatable about its axis and axially slidable in said casings above said member, said striker being provided with a transverse retaining lug traversing said slots; and
a compression spring in said first casing bearing upwardly against the latter and downwardly upon said striker for urging same toward said member, said slot having a first lower camming edge, said second slot having a lateral indexing notch normally receiving said lug and a second lower camming edge sloping downwardly from said notch, said lower camming edges having mutually inverted slopes and intersecting at a downwardly pointing vertex shifting laterally away from said notch upon depression of said first casing toward said member, said first slot further having an upper camming edge engageable with said lug in the course of a depression stroke and upon initial compression of said spring for dislodging said lug from said notch, thereby enabling said spring to expand and propel said striker into percussive contact with said member to energize said ignition circuit, with said lug moving along said first lower camming edge, said lug being intercepted by said first lower camming edge upon subsequent release of said first casing for cradling said lug in said vertex and exerting upon said second casing a restoring spring force relative to said second casing to return said lug to said notch.
2. A mechanism as defined in claim 1 wherein said first casing is received in said second casing.
3. A mechanism as defined in claim 1 wherein said casings are prismatic.
4. A mechanism as defined in claim 1 wherein said slots are provided with access passages facilitating the insertion of said lug into same.
5. A mechanism as defined in claim 4 wherein said first slot has a lower access passage at the upper end of said first lower camming edge, said second slot having an upper access passage above the level of said notch.
6. A mechanism as defined in claim 5 wherein said upper access passage has an inclined guide edge overlying said notch.
7. A mechanism as defined in claim 1 wherein said lug has the shape of a round pin.