Smokers lighter

A gas burning lighter with electrical spark ignition has a closed casing (11). Successive downward operative movements applied to an actuator slide (15) first releases a pivotal element (23) which moves outwards to an open position, creating a flame aperture (33) and opening a burner valve, and secondly operates a piezoelectric ignition mechanism to cause discharge of a spark and ignition of the gas to produce a flame (35).

BACKGROUND OF THE INVENTION 
The invention relates to a gas burning smokers' lighter comprising a 
casing; a fuel reservoir with a valve which controls the discharge of fuel 
gas through a burner nozzle located within the casing; an electrical spark 
ignition system for igniting fuel gas leaving the burner nozzle; and 
manually operated actuating means causing the burner valve to open and the 
ignition system to operate. Such a lighter is hereinafter referred to as 
of the kind described. 
Such lighters are subject to two important problems, which have not been 
solved wholly satisfactorily in the past. The first problem is the need to 
provide adequate protection for the delicate burner nozzle, burner valve, 
and sparking electrode(s). Such protection is important as experience 
shows that lighters frequently require maintenance because of an 
accumulation of foreign material adjacent to these parts or damage to 
these parts. The second problem is the difficulty in igniting the fuel gas 
first time upon operation of the ignition system. This arises because an 
electrical spark ignition system, such as a piezoelectric ignition system, 
usually produces a single spark for a short duration and the fuel gas/air 
mixture must be within a limited range of proportions in the immediate 
proximity of the spark if the gas is to be ignited. The difficulty is that 
the natural solution to the first problem is to enclose the burner nozzle 
and associated parts within a hollow upper part of a completely closed 
casing but this exacerbates the second problem by preventing the access of 
ignition air to the ignition zone adjacent to the burner nozzle until the 
casing is open to reveal the burner nozzle. 
One solution has involved a so-called "fully automatic" lighter in which a 
finger piece actuating member forming a part of the closed casing is 
engaged and physically moved relatively to the rest of the casing against 
spring action. The movement of the actuating member itself reveals the 
burner nozzle and provides access for ignition air to the burner nozzle, 
the movement also causing opening of the burner valve and operation of the 
ignition system. When the actuating member is released, it makes a return 
stroke under the spring action so as to close the burner valve and casing. 
Such lighters suffer from the drawback that the speed at which the 
actuating member is moved by the user determines whether the access for 
ignition air has been sufficiently long before the ignition system is 
operated for the gas and air to have formed an ignitable mixture when the 
ignition spark is discharged. Also, and more importantly, the movement of 
the actuating member must necessarily be continued until the ignition 
system is operated, and in practice slightly beyond this point to ensure 
that the ignition system is operated in spite of any tolerances in the 
parts. It follows that the trailing end of the actuating member which 
usually forms the burner cover when closed and a boundary of the air inlet 
passage and flame aperture when open, is moving adjacent to and disturbing 
the gas/air mixture in the ignition zone right up to the moment at which 
the ignition spark is discharged. The operation of the known fully 
automatic lighters in thus uncertain and subject to the vagaries of the 
user, and they will not operate satisfactorily irrespective of the manner 
in which they are operated. As a result, fully automatic lighters have a 
reputation for not providing first time ignition with sufficient 
reliability. 
Another solution involves the so-called "box-type" lighter in which the 
casing incorporates a hinged lid which is swung upwards or laterally to 
uncover the burner nozzle, and usually also to open the burner valve. 
However, the lid is a part vulnerable to damage and repair, is expensive 
and replacement thereof has involved replacement of the whole casing. Even 
if the swinging of the lid is responsible for opening the burner valve, 
this preliminary operation has to be followed by transference of the 
operator's thumb through an appreciable distance to a further actuating 
member for operating the ignition system and this has resulted in a 
somewhat tedious and clumsy manipulation of the lighter, as well as a 
waste of fuel gas prior to ignition. Further, in cases in which the lid 
has been swung upwards to uncover the burner nozzle, the lid has remained 
in an upwardly projecting position alongside the flame and has impeded the 
use of the flame. This solution, as that involving fully automatic 
lighters, is expensive in that the lid of the box type and the actuating 
member of the fully automatic lighter, which is displaced to uncover the 
burner nozzle, has needed to be large enough not only to cover the burner 
nozzle but to receive the user's thumb for displacement. Consequently the 
displacement part has provided such a relatively large proportion of the 
lighter casing that it has had to be embellished often in a similar manner 
to the rest of the casing and, being a separate part, this has involved 
two separate embellishment steps. If the embellishment involves any design 
which carries across the interface of the two parts, the embellishment 
becomes an even more expensive operation. 
SUMMARY OF THE INVENTION 
The object of the invention is to provide a construction which is less 
expensive than conventional lighters but which provides an ignition zone 
bounded by stationary parts and associated with an air inlet passage and 
flame aperture of accurately predetermined optimum size for such length of 
time before the ignition spark is discharged that, at that time, adequate 
air, and preferably an equilibrium mixture of gas and air, can be provided 
in the ignition zone with reasonable certainty. 
In accordance with the present invention, a gas burning smokers' lighter of 
the kind described is characterised in that there is an opening adjacent 
to the top of the casing at a junction of at least two faces of the 
casing; in that an element is movably positioned at the opening and, prior 
to operation of the lighter, is held in a closed position in which it 
cooperates with the casing substantially to close the opening, the element 
moving outwardly of the casing transversely to the direction in which the 
flame is projected from the casing to an open position, such displacement 
both resulting in the provision at the opening of a flame aperture through 
which the flame can be projected and opening an air inlet passage for the 
ingress of ignition air to an ignition zone within the casing upstream of 
the flame aperture; and in that a part of the actuating means is separate 
from the element, is exposed at the outer surface of the casing and 
cooperates inside the casing with the element in such a way that a first 
operative movement applied to the actuating means part causes the element 
to move from its closed position to its substantially fully open position, 
and a subsequent second operative movement applied to the actuating means 
causes operation of the ignition system. 
This construction provides a very neat way of substantially enclosing the 
burner nozzle and adjacent delicate parts, prior to operation of the 
lighter, while avoiding the problems of the prior art solutions. Thus in 
particular the provision of the element, which moves out of the closed 
casing to a predetermined protruding position upon initial operation of 
the lighter, ensures that an air inlet passage and flame aperture of 
predetermined size are automatically created upon initial operation, 
thereby providing the maximum time for ignition air to enter the ignition 
zone before the ignition spark is discharged, irrespective of how fast the 
user operates the actuating means. However, the element may be 
sufficiently small to preclude the necessity of embellishing the element 
identically to the rest of the lighter casing. 
The element may carry a trailing part in which the flame aperture is 
permanently formed, this trailing part being drawn from a position, 
overlying, but preferably underlying, the casing into alignment with the 
burner nozzle, upon displacement of the element to its open position. 
Alternatively, the trailing part may overlie, but preferably underlie, and 
close a flame aperture in part of the casing until the element is 
displaced whereupon the trailing part is drawn away from and leaves the 
flame aperture unobstructed. Most simply however the opening is formed 
partly by a slot which is filled by a complementary part of the element in 
its closed position, the element moving along and at least partly out of 
the slot when moving to its open position to create the flame aperture 
between a trailing part of the element and the closed end of the slot. 
These constructions all provide a flame aperture of predetermined size, 
preferably with lateral dimensions between 3.5 and 6.5 mm., and preferably 
with a cross sectional area of between 20 and 30 mm.sup.2. Thus when the 
flame aperture is created at the closed end of the slot, the slot part of 
the opening may have a width of between 3.5 and 6.5 mm. In any case, the 
part of the element adjacent to the flame aperture preferably moves 
transversely to the flame through a distance of between 3.5 and 6.5 mm 
when moving between its closed and open positions. An aperture of 
predetermined size can be arranged to ensure that the flame burns outside 
the casing and does not flicker back through the flame aperture into the 
casing. An evenly burning flame is also encouraged if the outer edge of 
the aperture is substantially at the same flame height position. For this 
reason when the flame aperture is created between a trailing part of the 
element and the closed end of the slot, the element preferably fills the 
slot with the outer surface of the element substantially flush with the 
corresponding casing face. It is not critical whether another part of the 
element overlies a casing face containing the opening but preferably the 
whole of the element fills the opening with its outer surface flush with 
the faces of the casing. 
Although the opening may be formed at the junction of three faces of the 
casing, it is sufficient if the opening is formed at the junction of only 
two faces of the casing. The opening may then be a slot running around the 
angular or arcuate corner from one face into the other. Thus, if the 
casing, adjacent to the opening, is elongate in horizontal section, the 
opening may be provided at the junction of an upper and a narrower side 
face of the casing. 
The element is preferably latched in its closed position and is released 
upon application of the first operative movement to the actuating means 
part whereupon the element springs out under spring action to its open 
position. This provides instant creation of the air inlet passage and 
flame aperture and hence the longest possible opportunity for air to flow 
into the ignition zone before sparking. In this case, the element may be 
held latched in its closed position by a catch which is released upon 
application of the first operative movement to the actuating means part, 
whereupon the element moves outwards under the spring urging. However, in 
a particularly simple construction, the element is latched in its closed 
position and urged to its open position by an over centre spring, the 
first operative movement applied to the actuating means part forcing the 
element to move past the dead centre position. 
Alternatively, most of the advantages of the invention are obtained if the 
element moves to its open position throughout the first operative movement 
of the actuating means part. Stationary and predetermined conditions are 
still achieved in the ignition zone prior to beginning of the second 
operative movement to activate the ignition system. In this case the 
element may be urged to its closed position under spring action, the 
actuating member cooperating with the element, e.g. via a cam and 
follower, such that the element is pushed outwards to its open position 
during the first operative movement of the slide and is then held open 
against the spring urging during the second operative movement. 
The element may be guided so as to slide along a straight or arcuate path. 
Preferably, however, it is pivoted about a horizontal or vertical axis 
internally of the casing but it will still be arranged so that, adjacent 
to the point at which the flame aperture is provided, the element moves 
substantially perpendicularly to the direction in which the flame is 
projected, at least during the initial part of its displacement to provide 
the flame aperture. The displacement of the element may be essentially 
laterally out of the wider or narrower side face of the casing in which 
case the operative movements applied to the actuating means are both 
preferably substantially vertical, particularly downwards, the actuating 
means cooperating with the element within the casing via some means, such 
as a cam and follower which convert the vertical movement to lateral 
movement. Alternatively the element may be displaced upwards, which would 
be appropriate in the case of a so-called pipe smokers' lighter in which 
the flame is projected laterally from adjacent the top of the casing. 
It is convenient if, as seen perpendicularly both to the direction in which 
the flame is projected from the casing, and to the direction in which the 
element is moved outwardly of the casing, the actuating means part which 
is responsible for displacement of the element is offset relatively to the 
centre line of the flame in a direction opposite to that in which the 
element is moved outwardly of the casing away from the centre line of the 
flame. Thus if the lighter has a casing of rectangular prismatic form, an 
appropriate construction would involve projection of the flame upwardly 
from a flame aperture created in a top face of the casing, the element 
being displaced from a narrow edge of the top of the casing parallel to 
the centre line of the top of the casing. The actuating means part might 
then be mounted on a wider side face of the casing adjacent to the 
opposite narrower side face of the casing, or might work in an opening in 
the opposite narrower side face of the casing. Similarly in the case of a 
pipe smokers' lighter, in which the flame is arranged to be projected 
laterally from an upper part of a narrower side face of the casing, the 
element may be displaced upwards to create a flame aperture upon the first 
operative movement being applied to an actuating means part mounted below 
the flame height, on a wide face of the casing. 
The first operative movement applied to the actuating means part may cause 
only displacement of the element, and consequential creation of the flame 
aperture and air inlet passage. The burner valve may then be opened and 
the ignition system operated either simultaneously or successively upon 
application of the second operative movement to the actuating means. 
Preferably, however, the burner valve is opened substantially 
simultaneously with the displacement of the element to its open position, 
as a result of the first operative movement applied to the actuating means 
part. This contributes to even better "timing" of the lighter operation in 
that the fuel gas will be flowing from the burner nozzle almost as soon as 
the air inlet passage has been opened, so that a dynamic equilibrium 
mixture of gas and air will be formed in the ignition zone, prior to the 
subsequent sparking upon application of the second operative movement to 
the actuating means and hence operation of the ignition system. The burner 
valve may be arranged to remain open without the continued application of 
manual force to the actuating means and subsequently to be closed when the 
element is returned to its closed position, either upon retraction of the 
actuating means part, or by direct manual force applied to the element. 
The element, when in its protruding position, will then act as a flag 
indicating to the user that the burner valve is open and that gas is being 
discharged through the burner valve. 
Both the first and second operative movements may be applied to a common 
actuating member of the actuating means, such as thumbpiece slide, which 
moves over a surface of the lighter and is connected to the element, to 
the burner valve, and to the ignition system within the casing by a 
connection extending through a second casing opening, such as a slot. The 
successive operative movements might then be applied by moving the slide 
progressively along the slot, or to and fro along the slot, by the user's 
thumb. Alternatively, the actuating means may incorporate two separate 
actuating members which operate in the same or separate casing openings. 
For ease of operation they are, however, preferably mounted adjacent to 
one another. When there are two actuating members, they will be intended 
to be operated in sequence and the first to be operated may be a button 
and will release the element to cause its displacement and provide the 
flame aperture, and possibly also open the burner valve. The second 
actuating member will then control the operation of the ignition system. 
When there are two actuating members, they are preferably immediately 
adjacent to one another so that there is a minimum of inconvenience in 
moving the user's thumb from the one to the other. When the actuating 
means comprises a slide member which is movable to open the burner valve, 
this movement may expose an indicator which is covered when the slide 
makes a return stroke upon reclosure of the burner valve. This provides a, 
or a further, warning to the user when the burner valve is open.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Each of the illustrated examples of lighter has a rectangular prismatic 
box-shaped casing 11 with a wide front side face 12, a rear side face of 
similar size, two narrow side faces 13, and a top face 14. The casing has 
an actuating thumbpiece slide member 15 which can be pulled downwards by 
frictional entrainment by the user's thumb to operate the lighter. In 
examples one to four and six the slide is mounted on the front face 12 of 
the casing, and in the fifth example on a narrow side face 13. In the 
first three examples the slide member is recessed slightly into the casing 
face. 
In each example the casing contains a liquefied gaseous fuel reservoir tank 
16 having an inlet valve 17, and a burner valve 18 carrying a burner 
nozzle 19. The casing also contains a piezoelectric ignition unit 20 which 
is operated by depression of a plunger upon downward movement of the 
actuator slide 15, which is coupled to the plunger. The electrical output 
of the unit 20 is connected to the burner nozzle 19, and to an adjacent 
electrode 21. 
An L-shaped slot opening 22 is formed in the casing at the junction of the 
faces 13 and 14 and in the rest position shown in FIG. 1 and in full lines 
in FIG. 3, the opening is filled by a G-shaped closure element 23, the 
outer surface of which is then flush with the surfaces 13 and 14. The 
closure element is pivotally mounted within the casing about an axis 24 so 
as to be capable of pivoting between the closed position shown in FIG. 1 
and in full lines in FIG. 3, and an open position shown in FIG. 2 and in 
chain dotted lines in FIG. 3. The closure element is latched in both its 
open and closed positions by bistable biasing means in the form of an over 
centre spring arrangement comprising one link 25 which is pivoted within 
the casing at 26 and which cooperates telescopically with a second link 27 
pivoted at 28 to the element 23. A helically coiled compression spring 29 
is contained within the links 25 and 27 so as to urge them apart. It will 
be appreciated that as the element pivots through a dead centre position, 
the spring 29 is compressed and then allowed to expand. 
The link 27 has a lateral arm 30 cooperating with an inclined cam surface 
31 on the slide 15. The element 23 also has a bifurcated cam foot 32 which 
straddles the nozzle 19 and engages a flange at the top of the burner 
valve 18. In its closed position, the element 23 holds the flange down and 
the burner valve closed but when the element moves to its open position, 
it allows the burner valve flange to rise and the valve to open so that 
gas is discharged through the nozzle 19. 
Starting from the closed position shown in FIG. 1 and in full lines in FIG. 
3, the lighter is operated by drawing the actuator slide downwards. During 
the first part of this stroke, the cam surface 31 forces the link 27 to 
the left as shown in FIG. 3, thereby causing the element to tilt in the 
same direction. When the dead centre position of the spring 29 is passed 
the element becomes unlatched and jumps out to its open position both 
under the action of the spring 29 and under the action of the internal 
spring in the burner valve 18. This movement causes the upper part of the 
element 23 to be withdrawn almost completely out of the part of the slot 
22 in the upper face 14, thereby creating a flame aperture 33 of 
predetermined length and width, and also creating on each side air inlet 
passages 34 into an ignition zone 35 around the burner nozzle 19 as a 
result of the inner wall of the element 23 moving outwardly of the 
adjacent side face 13. Simultaneously the release of the burner valve 
causes gas to be discharged through the nozzle into the ignition zone 35. 
Continued downward movement of the actuating slide 15 causes an 
overhanging part 58 at the top of the slide to engage and push down on a 
plunger 59 of the piezoelectric unit 20 until the unit is actuated and a 
spark is discharged between the electrode 21 and the nozzle 19, thereby 
igniting a flame 36. Upon release of the slide 15, it will move back 
partway upwards to the FIG. 2 position under the action of the return 
spring of the plunger of the piezoelectric unit 20. 
The flame will continue to burn and the element 23 will remain in its 
protruding position without the application of further pressure to the 
actuating slide 15. When it is subsequently desired to shut off the flame, 
the user applies his thumb to the left hand edge of the element 23 as 
shown in FIG. 3 and pushes it back into the casing. This presses down the 
burner valve flange thereby shutting off the gas flow and flame, forces 
the links 25 and 27 back past the dead centre position so that the spring 
29 is then urging the element 23 inwards, and forces the actuator slide to 
its uppermost position as a result of the engagement between the arm 30 
and the cam 31. Apart from the protrusion of the element 23, which acts as 
a flag indicator when the burner valve 18 is open, an indicator 37 is also 
provided in the recess for the actuator slide 15. This indicator may carry 
some message such as "gas open", or exhibit a picture of a flame, and will 
be brightly coloured, e.g. red. The indicator will thus be revealed when 
the slide 15 is in its mid-position or lower but covered when the slide 
has been forced to its uppermost position upon return of the element 23 to 
its closed position. 
The second example illustrated in FIG. 4 is very similar to the first 
example and only the differences will be described. Parts analogous to 
parts in the first example bear the same reference numeral with the suffix 
A. A similar procedure will be adopted for the subsequent examples but 
with suffixes B, C etc. 
The actuator is again a slide 15A but in this case it carries an inclined 
cam surface 31A which cooperates with a projecting arm 30A which is 
carried by the element 23A, rather than by the link 27A. The actuator 
slide 15A is thus moved upwards from its rest position to release the 
element and cause the burner valve to open. 
The actuator slide 15A carries a pin 38 which works in a slot 39 in an 
auxiliary actuator slide 40 mounted behind the slide 15A. When the slide 
15A is moved upwards to release the element 23A the slide 40 is not moved. 
The piezoelectric unit 20A is operated to cause discharge of the ignition 
spark by subsequently moving slide 15A down further than it had previously 
been moved up, so that the pin 38 engages in the bottom of the slot 39 and 
the slide 40 is thereafter carried downwards with the slide 15A, and 
carries the plunger 58A of the unit 20A downwards. Removal of the user's 
thumb from the slide 15A then causes both slides to move back to the 
position illustrated in FIG. 4, under the action of the return spring in 
the unit 20A. In this example there will be no indicator equivalent to the 
indicator 37. 
FIG. 5 and 6 show a third example which is another modification of the 
first example and only the differences will be described. 
In this example the element 23B is held latched in its closed position, not 
by an over centre spring arrangement, but by a catch member 41 which is 
pivoted in the casing about an axis 42 and has a hook end 43 cooperating 
with a hook 44 on the element 23B. The actuator slide 15B carries a pin 45 
which engages with a shoulder 46 on the catch member 41. Both the catch 
member 41 and the element 23B are urged to rotate in the counterclockwise 
direction as seen in FIG. 5 by the respective arms of a hairpin torsion 
spring 48. 
In the rest position shown in FIG. 5, the hook end 43 engages over the hook 
44 to hold the element 23B closed. When the actuator slide 15B is drawn 
downwards the pin 45 pushes down on, and then rides over, the shoulder 46, 
causing the catch member 41 to rotate in the clockwise direction against 
the action of the spring 48. This movement disengages the hook end 43 from 
the hook 44 so that the element jumps outwards to its FIG. 6 position. 
Simultaneously the catch member 41 engages beneath a flange 49 on the 
burner nozzle, lifting the burner nozzle and hence opening the burner 
valve 18B. Further downward movement of the actuator slide 15B depresses 
the plunger 58B of the piezoelectric unit 20B and causes discharge of the 
ignition spark. The lighter is a semiautomatic lighter in the sense that 
although the actuator slide 15B may be allowed to rise slightly under the 
action of the return spring for the plunger of the unit 20B, continued 
downward pressure must be applied to the slide 15B to maintain the burner 
valve open so that the flame continues to burn. As soon as the user 
removes thumb pressure from the slide 15B, the spring 48 rotates the catch 
member 41 in the counterclockwise direction, thus causing the slide 15B to 
rise to its rest position and allowing the burner valve 18B to close under 
its internal spring reaction. The element 23B is subsequently returned to 
its rest position by manual pressure applied to the left hand side of the 
element as shown in FIGS. 5 and 6. As the element approaches its fully 
closed position, the hook end 43 is caused to lift slightly as it rides 
over the hook 44 against the action of the spring 48 until the hook end 43 
snaps over the hook 44 to lock the element in its closed position. 
FIGS. 7 and 8 show an alternative construction in which the element 23C is 
mounted in a similar position to the element 23 but is guided so as to 
slide linearly to its protruding position shown in FIG. 8, again under 
spring action upon being unlatched. In this case the flame aperture 33C is 
provided in a trailing portion of the element and is exposed in the 
opening 22C. Air inlet passages 34C are provided through holes exposed 
when the element 23C is in its protruding position, and leading through a 
hollow interior of the element to the ignition zone. This example of 
lighter has two actuator parts, a plunger 50 and a slide 51. To operate 
the lighter the user places his thumb on top of the plunger 50 and presses 
downwards, this action releasing the element 23C, the thumb movement 
continuing down over and onto the slide 51 which is drawn downwards to 
depress a plunger of a piezoelectric unit. 
In the fifth example, illustrated in FIGS. 9 and 10, the element 23D is 
pivotally mounted similarly to the element 23 but in an opening at the 
junction of an upper or tap face 14D and a wide front face 12D of the 
casing. On the tap face 14D a flame aperture 33D is created when the 
element is released and jumps partly out of the front face of the casing. 
In this position air inlet passages 34D are provided to the inlet zone 
through slots in the sides of the element 23D, leading through the 
interior of the element. In this example the element is released and the 
burner valve opened, and the piezoelectric unit is subsequently operated, 
by the successive two stage downward movement of an actuator slide 15D, 
mounted at a narrower side face 13D of the casing, in an analogous manner 
to the first example. 
The sixth example, illustrated in FIGS. 11 and 12, has similarities with 
the first and second examples, but one difference is that the element 23E 
is continuously urged to its closed position shown in FIG. 11 by a hairpin 
torsion spring 52 which is mounted on the element pivot 24E and has one 
arm bearing against the casing wall 13E and the other arm engaging in an 
aperture 53 in the element. 
Similarly to the FIG. 4 example, the element 23E has a projecting arm 30E 
carrying a cam follower roller 54 which runs on a cam surface of the 
actuator slide 15E. The cam surface incorporates an inclined portion 55 
leading out of a notch 56 in the actuator onto a vertical portion 57. 
Starting from the rest position shown in FIG. 11, the lighter is operated 
by pushing the actuator slide 15E upwards. This initially causes the 
element 23E to swing out to its open position shown in FIG. 12, as the 
roller 54 rides up the inclined cam portion 55, thereby creating the flame 
aperture 33E and air inlet passages 34E. When the roller 54 reaches the 
lower end of the inclined cam portion 55, it rides onto vertical portion 
57. Thereafter further upward movement of the slide 15E leaves the element 
23E stationary in its fully open position. Such further upward movement of 
the actuator slide 15E is necessary then to pick up and raise the plunger 
58E of an inverted piezoelectric ignition unit 20E, until a spark is 
discharged between the burner nozzle 19E and electrode 21E to ignite the 
flame 36E. 
This example of lighter is fully automatic in the sense that continued 
upward pressure must be applied to the actuator slide 15E to maintain the 
element 23E open and the flame 36E burning. As soon as the slide is 
released, it moves downwards initially under the return spring for the 
plunger 58E, and subsequently when the roller 54 reaches the inclined cam 
portion 55, under the reaction of the spring 52 which tends to return the 
element 23E to its closed position. The spring 52 is stronger than the 
spring in the burner valve 18E so that the burner valve is pushed 
downwards to close the valve by the foot 32E of the element 23E when the 
element is pivoted back to its closed position.