GB2242257A - Initial manual opening of an electromagnetic safety valve in a gas feed device for a gas burner - Google Patents

Abstract

A gas feed device for a gas burner, particularly in a flat type household appliance, comprises a gas intake (3), a gas flow regulation element (4) rotated by a control shaft (6, 6a) which shaft is also movable axially (first direction) against bias of spring (8), a safety valve (11) comprising an electromagnet fed by a thermocouple and disposed downstream of the regulation element (4), this valve having a clapper (12) mounted on a setting nod (12a) movable axially (second direction), and a change of direction movement transmission device (15), inserted between the control shaft (6, 6a) and the setting rod (12a) of the valve. The transmission device (15) comprises a resiliently deformable element (16) having a first anchorage end (18) bearing on two abutment surfaces (22a, 22b), a second end (19) which is free to move in the second direction for setting the safety valve and which bears against an abutment surface (10a), and a bearing zone (17) for cooperating with the control shaft (6, 6a). A guided stirrup (23) is positioned between the control shaft and the bearing zone. <IMAGE>

Description

Gas feed device for a gas burner, particularly for a flat type household appliance, equipped with an angular movement transmission member The present invention relates to improvements to gas feed devices for a gas burner, particularly in a flat type household appliance, comprising - a gas intake, - a gas flow regulation element rotated by a control shaft which is also movable axially (first direction) said shaft extending downstream of the regulation element, - a safety valve comprising an electromagnet fed by a thermocouple and disposed downstream of the regulation element, this valve having a clapper mounted on a setting rod movable axially (second direction) forming an angle with said control shaft, - and a change of direction movement transmission device inserted between the control shaft and the setting rod of the valve.

The construction of household gas appliances of flat or extra flat type (for example cooking plates equipped with at least one gas burner) raises important problems for housing the components. In so far as the gas supply devices are concerned for controlling respective burners, it is current practice for the gas flow regulation knobs to be situated on the top of the cooking plate, with supply taps disposed vertically under the plate. However, the assembly height provided for such cooking plates is too low for housing therein, in the extension of the taps, certain auxiliary components, such for example as safety valves fed by thermocouple with manual setting.

This is why, for this kind of apparatus, the safety valves are housed no longer in the extension of the gas supply taps but on the side thereof, for example approximately perpendicular thereto. The control movement change of direction, from an axial movement of the shaft actuating the gas flow regulation tap, is provided by change of direction mechanisms comprising levers and/or wedge and cam systems.

Thus, the movement change of direction mechanisms used up to now, whatever their construction, are relatively cumbersome and difficult to position, even to manufacture, and their operation may, because of the friction which occurs between the moving parts and the risk of jamming, is not reliable, with consequently a relatively short useful life.

The object of the present invention is then essentially to provide a linear movement angular change of direction mechanism for gas supply devices which, in as large a measure as possible, overcomes the drawbacks of equivalent medhanisms used up to now, and which in particular is of a simple structure, without articulated elements, with a minimum of rubbing parts for reducing the resistance and wear, which is easy to manufacture with simple tooling, which is easy to position and which requires no adjustments or maintenance; furthermore, a mechanism is also sought which is not cumbersome and which does not have an extensive transversal area so that it can be fitted inside the gas flow duct without appreciably disturbing the gas flow.

To this end, a gas supply device of the type mentioned in the preamble is essentially characterized, according to the present invention, in that it comprises a resiliently deformable element having a first anchorage end bearing on two abutment surfaces which are substantially perpendicular respectively to the first and second said directions, a second end which is intended to cooperate with the rod for setting the safety valve and which bears against an abutment surface substantially perpendicular to said first direction, and a bearing zone cooperating with the control shaft and situated between the first and second ends.

With such an arrangement, the distance separating the first and second ends of the resiliently deformable element is modified under the action of the force exerted on the bearing zone by the control shaft and the axial movement thereof is transformed into an accompanying axial movement of the rod for setting the safety valve.

Advantageously, the resiliently deformable element is not aligned with the first and second ends of said element, which makes it possible to increase the amplitude of movement of the second end of the resiliently deformable element for a given amplitude of axial movement of the control shaft.

In one embodiment, the resiliently deformable element has the general form of a V whose tip, forming said bearing zone, is turned towards the control shaft; thus, the movement of the control shaft causing crushing of the resiliently deformable element results in a movement in the same direction of the safety valve setting rod. In one particularly advantageous embodiment, the resiliently deformable element is formed by a metal wire having several turns in the connection zone of the legs of the V and the bearing zone is formed by the external surface of the turns.Such a resiliently deformable element is then manufactured from an inexpensive raw material (spring steel wire) and may be produced by bending and winding the wire with simple, inexpensive machines which are currently available in workshops; in addition, thus arranged, the resilient deformability of the element in question is increased and the mutual spacing between its ends may be high.

Still with the object of simplifying the assembly of the device, the anchorage end of the deformable element is curved into a loop housed in a recess in the wall of the device body and the two corresponding abutment surfaces are surfaces partially defining this recess.

So as to obtain then reliable operation, avoid rubbing of the parts one on the other, even jamming thereof, and to be sure of correct transmission of the forces, it is advantageous for the bearing zone of the deformable element to be capped by a slidingly guided stirrup and for the control shaft to cooperate with this stirrup.

In such a configuration of use, the movement change of direction element may be housed inside the gas supply duct, under the gas tap, at the intersection of the duct sections, which may be approximately perpendicular to each other, housing respectively the supply tap and the safety valve; the stirrup is then guided by the wall of the duct section housing the supply tap, whereas the second end free and movable end of the deformable element bears on the wall of the other duct section housing the safety valve.

It will be noted here that the arrangement in accordance with the present invention has the very important advantage that the movement change of direction element is formed in a single piece and its parts sliding on guide surfaces are few and may have short strokes. So there is no risk of jamming of the elements nor considerable risks of wear and the lifespan of said element may be long. Furthermore, in a practical construction, the control shaft is returned to its initial position by its own spring and cooperation between the control shaft and the first end of the deformable element, on the one hand, and between the safety valve setting rod and the second end, on the other hand, may be provided by a simple bearing relation (in other words without a positive connection between these elements); thus, each element remains free to return to its own initial position under the action of its own resilience and/or its own resilient return means and thus again risks of janing are avoided which are likely to prevent closure of the clapper of the safety valve in the case of need.

The invention will be better understood from the following detailed description of a preferred embodiwtent given solely by way of example. In this description, reference is made to the accompanying drawings in which Figure 1 is a side view in cross section of a gas supply device for a gas burner arranged in accordance with the invention; and Figure 2 is a front view, on a larger scale, of a movement change of direction element adapted in accordance with the invention and mounted in the device of figure 1, The gas supply device 1 comprises a solid body 2 with a gas intake orifice communicating horizontally with the faucet plug 4, with vertical axis, of a tap 5 for regulating the gas flow. This tap has a vertical actuating shaft 6a whose free upper end is adapted to receive a control knob (not shown).At its opposite end, the actuating shaft 6a has a projecting radial pin 7 engaged in a vertical groove 4a of plug 4 so as to create a rotational coupling of the shaft and the plug while leaving the shaft 6a free to move axially with respect to plug 4.

Furthermore, although it is not very visible in figure 1, pin 7 is extended beyond said groove 4a so that its free end is engaged in a groove 2b formed in the inner face of a cap 2a capping plug 4 and integral with body 2. Groove 2b has a vertical rectilinear portion which can be seen in figure 1 and a circular portion transversal to shaft 6a connected to the rectilinear portion towards the bottom thereof.

Under shaft 6a and in the extension thereof there extends a second shaft or transmission shaft 6 which is permanently urged against the lower end of the actuating shaft 6a by a spring 8. The axial movement of the actuating shaft 6a causes an identical movement of the transmission shaft 6, whereas the latter remains free with respect to the rotational movements of the actuating shaft 6a; conversely, the return spring 8, acting on the transmission shaft 6, also returns the actuating shaft 6a to an initial axial position.

Although shafts 6a and 6 are structurally separate to facilitate manufacture and assembly of the parts, they are functionally interlocked in so far as their axial movements are concerned which are more specially taken into consideration within the scope of the present invention. In what follows, these two shafts will therefore be designated globally under the single name of control shaft 6 for the regulation tap.

The lower end of shaft 6 extends axially in a duct section 9 at the output of faucet plug 4, which section 9 is connected at right angles to another duct section 10 in which is housed a safety valve 11 having an electromagnet fed by a thermocouple (not shown). The clapper 12 of the safety valve bears sealingly, under the action of a spring 12b, against an annular seat 13 formed by a shoulder on the duct section 10. This clapper 12 is carried at the end of an axially movable rod 12a which forms the core of the electromagnet or is fast with the core thereof.

Downstream of clapper 12, the duct section 10 is connected to an outlet orifice 14 connected to the gas burner (not shown).

The operation of the device which has just been described is the following. With tap 5 closed, the clapper 12 of the safety valve is held against its seat by it spring 12b. To bring the burner into operation, pressure is applied axially on shaft 6 of the regulation tap. This axial movement is transmitted via a movement change of direction device 15 housed at the intersection of the gas duct sections 9 and 10, to the rod 12a of the safety valve 11 so that this rod is moved in the opening direction of valve 12 (leftwards in figure 1). Shaft 6 having been simultaneously rotated for opening tap 4, the gas flows as far as the burner where it bursts into flame. Said thermocouple then generates an electric current which is applied to the electromagnet of the safety valve 11.The electromagnet, thus energized, holds rod 12a in the position which it occupies with clapper 12 in the open position. As soon as the electromagnet is energized, shaft 6 may be released and it is is returned to its original axial position by spring 8, while keeping its angular position controlling the opening of plug 4.

As soon as the burner is extinguished, the electromagnet is no longer energized and, since rod 12a is no longer retained, spring 12b returns clapper 12 to its seat 13 so as to cut off the flow of gas.

The movement change of direction device comprises a resiliently deformable element 16 (formed for examplefrom spring steel) which has a generally curved or V shape with its convexity 17 turned towards the free end of shaft 6.

One of its ends 18 is anchored or bears (the csse shown) in the body 2 of the device, whereas its other end 19 remains free and is situated opposite and close to the end of the rod 12a of the safety valve.

When shaft 6 has moved downwards, it exerts a force on the convex portion of the resiliently deformable element 16 and the latter, being crushed, extends in horizontal projection. With end 18 anchored or , in horizontal abutment, the increase of horizontal length is transferred to end 19 which pushes back clapper 12 and its rod 12a and sets the safety valve 11. During this movement, end 19 is placed in abutment (for example by a bent portion 20) against the internal wall 10a of the duct section 10 and is guided thereby.

In the example shown in figures 1 and 2, the deformable element 16 is formed by a metal rod. This rod may be single and be bent and wound in the manner of a clothes peg spring and the upper loop 21 forms the spring portion conferring the required resilience for this element. Shaft 6 bears on this loop. The anchorage end 18 is bent in a loop on itself (see figure 1) so as to fit into a housing 22 formed by an extension of duct section 10 beyond section 9. Thus, this housing 22 has a first bearing surface 22a which is perpendicular to the control shaft 6 and on which abuts a portion 18a of loop 18 and a second bearing surface 22b which is perpendicular to the setting rod 12a and on which abuts another portion 18b of loop 18; thus, the portion 18b of loop 18 is in abutment in both directions in which the reaction bearing forces are exerted.

To ensure correct cooperation of the end of shaft 6 and of said loop 21, a stirrup 23 is provided which freely caps this loop 21 and on which shaft 6 bears This stirrup 23 is guided in its movement by its legs 24 which cooperate with the internal wall of the duct section 9.

To avoid excessive penetration of shaft 6, likely to cause prejudicial crushing of the deformable element 16, it is possible to dispose an annular spring ring 25 on the actuating shaft 6a: this spring ring serves as an axial stop by cooperating with the edge of a cylindrical portion of cap 2a forming a bearing 26 for the actuating shaft 6a.

The position of the spring ring 25 may advantageously be chosen so that the safety valve 11 can be set not only when this ring bears against bearing 26, but also if it is slightly spaced apart therefrom so as to make adjustment easier for operation of the tap by the user.

As is evident, and as it follows moreover already from what has gone before, the invention is in no wise limited to those of its modes of application and embodiments which have been more particularly considered; it embraces, on the contrary, all variants thereof.

Claims (10)

1. Gas feed device for a gas burner, particularly in a flat type household appliance, comprising - a gas intake (3), - a gas flow regulation element (4) rotated by a control shaft (6) which is also movable axially (first direction) said shaft extending downstream of the regulation element, - a safety valve (11) comprising an electromagnet fed by a thermocouple and disposed downstream of the regulation element (4), this valve having a clapper (12) mounted on a setting rod (12a) movable axially (second direction) forming an angle with said control shaft, - and a change of direction movement transmission device (15) inserted between the control shaft (6) and the setting rod (12a)of the valve, characterized in that the movement change of direction device (15) comprises a resiliently deformable element (16) having a first anchorage end (18) bearing on two abutment surfaces (22a, 22b) which are substantislly perpendicular respectively to said first and second directions, a second end (19) which is intended to cooperate with the rod (12a) for setting the safety valve and which is free to move in the second direction and bears against an abutment surface (10a) substantially perpendicular to said first direction, and a bearing zone (17) cooperating with the control shaft and situated between said first and second ends, whereby the distance separating the first and second ends of the resiliently deformable element is modified under the action of the force exerted on the bearing zone by the control shaft and the axial movement thereof is transformed into an accompanying axial movement of the rod for setting the safety valve.

2. Device according to claim 1, characterized in that the bearing zone (17) of the resiliently deformable element is not aligned with the first and second ends of said element.

3. Device according to claim 2, characterized in that the resiliently deformable element (16) has the general form of a V whose tip (17), forming said bearing zone, is turned towards the control shaft (6), whereby the movement of the control shaft causing crushing of the resiliently deformable element results in a movement in the same direction of the safety valve setting rod.

4. Device according to claim 3, characterized in that the resiliently deformable element (16) is formed by a metal wire having several turns (21) in the connection zone (17) of the legs of the V and in that the bearing zone is formed by the external surface of the turns.

5. Device according to any one of claims 1 to 4, characterized in that the anchorage end (18) of the deformable element (16) is curved into a loop housed in a recess (22) in the wall of the device and in that the two corresponding abutment surfaces (22a, 22b) are surfaces partially defining this recess.

6. Device according to any one of claims 1 to 5, characterized in that the bearing zone of the deformable element (16) is capped by a slidingly guided stirrup (23) and in that the control shaft (6) cooperates with this stirrup (23).

7. Device according to any one of claims 1 to 6, characterized in that the control shaft (6) and the setting rod (12a) of the safety valve extend approximately perpendicularly to each other.

8. Device according to any one of claims 1 to 7, characterized in that the control shaft is equipped with an axial abutment element (25) limiting the axial movement of said shaft.

9. A device for a gas burner substantially as herein described with reference to and as shown in the accompanying drawings.

10. Any novel feature or combination of features disclosed herein.