Electrical harness for wiring the electrical ignition circuit of a cooking appliance with gas burners

An electrical harness for wiring the electrical ignition circuit of a cooking appliance equipped with a plurality of gas burners each provided with a remote-controlled electrical ignition element, comprising: a low-voltage electrical power supply line (1), one of the ends of which is provided with respective terminals (2) for its electrical connection to a low-voltage electrical power supply; a plurality of high-voltage generating units (3), the number thereof being equal to the number of gas burners (10), and being electrically connected to the said power supply line, each unit (3) comprising a switch (4) to control the power supply and being provided with means (5) for fast mechanical connection for connecting the same to the respective gas tap body; mechanical connecting means (6) for mechanically connecting each of the high-voltage generating units (3) to the electrical power supply line (1); and respective high-voltage output lines (7) from the high-voltage generating units (3), the free ends of said lines being provided with a terminal (8) for connection to the respective ignition element.

This invention relates to improvements to cooking appliances provided with 
gas burners and, more particularly, relates to improvements to the wiring 
of the electrical ignition circuit of a cooking appliance equipped with a 
plurality of gas burners each provided with a remote-controlled electrical 
ignition element. 
The electrical ignition circuit of gas burners was hitherto installed by 
individually fitting the components and the wires during the manufacture 
of the cooking appliance. However, this conventional assembly process is 
unsuitable for economic manufacture. Assembly component by component is a 
long process; wiring an ignition circuit with simultaneous control of all 
the igniters is complicated and requires a high-voltage transformer unit 
dimension for the exact number of igniters to be controlled, and hence 
this complicates supply and stock-keeping; moreover, the wiring of an 
ignition circuit with individual control of the igniters is even more 
complicated and, therefore, little used. In every case, the fitting of the 
circuit is accompanied by making numerous connections in situ and hence 
under conditions such that the reliability of the circuit is greatly 
reduced and the number of electrical breakdowns is high right from the 
start of the operation of the appliance. 
The main object of the invention therefore is to obviate the above 
disadvantages and propose a solution which is adapted not only to simplify 
the step of wiring the ignition circuit of the burners of the cooking 
appliance but also, because of such simplification, allows standardisation 
of the fitting of an individual ignition circuit to the burners and 
generally leads to reduced costs with increased reliability. 
For these purposes, the invention proposes prefabricating in a specialised 
workshop an electrical harness for wiring the electrical ignition circuit 
of a cooking appliance equipped with a plurality of gas burners each 
provided with a remote-controlled electrical ignition element, such 
harness arranged according to the invention being essentially 
characterised in that it comprises: 
a low-voltage electrical power supply line, one the ends of which is 
provided with respective terminals for its electrical connection to a 
low-voltage electrical power supply, 
a plurality of high-voltage generating units, the number thereof being 
equal to the number of gas burners, and being electrically connected to 
the said power supply line, each unit comprising a switch to control the 
power supply and being provided with means for fast mechanical connection 
for connecting the same to a gas tap body controlling the supply of gas to 
the respective burner, 
mechanical connecting means for mechanically connecting each of the 
high-voltage generating units to the electrical power supply line, 
and respective high-voltage output lines from the high-voltage generating 
units, the free ends of said lines being provided with a terminal for 
connection to the respective ignition element. 
Very advantageously, it also comprises gas taps mechanically connected, 
more-particularly by snap action, to the respective high-voltage generator 
units. 
Pre-wiring the harness in a specialised workshop enables this work to be 
carried out with every attention and all the technical expertise required, 
which the manufacturers of cooking appliances could not hitherto readily 
combine in their own assembly workshops. 
Also, the arrangement used to form the harness results in a modular 
structure which allows easy and rapid adaptation to diverse configurations 
of cooking appliances (i.e. in respect of number of burners, burner layout 
on the top plate, location and mutual spacing of gas taps, and so on). 
Also, the modular series structure of the said harness enables individual 
control of the burner ignition to be embodied more simply and more cheaply 
than previously. 
Finally, each module has as its function to ignite only one burner and all 
the modules can be made identical: only one type of high-voltage 
transformer is required and, being of reduced power, is cheaper and 
smaller. To this we may add the advantage of the choice of the finish for 
the modules, which may either include just the high-voltage generator unit 
or combine the latter and the gas tap interconnected to one another. 
Finally, and by no means least, the structure adopted for the harness 
greatly reduces the number of connections with respect to conventional 
wiring; this not only results in simplification of its manufacture but, in 
particular, the number of breakdowns due to the electrical circuit of the 
cooking appliances sold is considerably reduced. 
Advantageously, the gas taps are mechanically connected to the respective 
high-voltage generator units in such manner that the switch is controlled 
so as to be closed by an axial actuation of the shaft of the gas tap. 
Preferably, for appreciable simplification of production of the harness, 
the means for fast mechanical connection of each high-voltage generator 
unit to the power supply line are adapted simultaneously to form the 
electrical connection means between said unit and said line, more 
particularly when the means for electrically connecting each high-voltage 
generator unit to the power supply line are adapted automatically to 
perforate an insulating sheath or sheaths protecting the line.

Referring to FIG. 1, a simple version of an electrical harness A is shown 
very diagrammatically, such harness being arranged according to the 
invention for wiring the electrical ignition circuit of a cooking 
appliance (a domestic appliance such as a cooker, or hob) provided with a 
number of gas burners each provided with a remote-controlled electrical 
ignition means. Said harness comprises: 
a low-voltage electrical supply line 1, one of the ends of which (the free 
end) is provided with respective terminals 2 for its electrical connection 
to a low-voltage electricity power supply; in practice this will be the 
mains power supply (e.g. 220 V AC 50 Hz) and the line 1 is a three-wire 
line (two phase wires and one earth line ); 
a number of high-voltage generator units 3, the number of these being equal 
to the number of gas burners (three in FIG. 1); each unit 3 comprises a 
high-voltage transformer with a primary winding connected electrically to 
the said power line 1; since each unit is intended only for controlling a 
single ignition element, the transformer is a low-power transformer of 
restricted size and occupying little space, its cost being reduced; each 
unit 3 is also provided with a power supply switch 4 for the primary 
winding of the corresponding high-voltage transformer, one example of the 
connection of the switch being given hereinafter; finally, each unit 3 is 
provided with means 5 for quick mechanical connection (e.g. by snap 
action) to connect it to a gas tap body controlling the gas supply to the 
respective burner; 
mechanical connecting means 6 for mechanically connecting each of the units 
3 to the power supply line 1; and 
respective high-voltage output lines 7 from the units 3, their free ends 
being provided with a terminal 8 for connection to the respective ignition 
element. 
To simplify and accelerate the production of the harness, the means 6 for 
mechanically connecting each high-voltage generator unit 3 to the power 
line 1 are of the rapid fitting type and are so arranged as simultaneously 
to form the means for electrically of the rapid fitting type and are so 
arranged as connecting each unit 3 to the said line 1; for this purpose, 
the means for electrically connecting each high-voltage generator 3 to the 
line 1 are adapted automatically to perforate an insulating sheath or 
sheaths protecting the line 1. In this way, the power supply line 1 
remains unitary and without any gap, i.e. it extends continuously from the 
terminals 2 to the last unit 3 without any intermediate connections, and 
this is so irrespective of the number of units used. Numerous embodiments 
of such mechanical and electrical connection means are known to the 
skilled man. 
FIG. 2 is a highly diagrammatic illustration of one preferred embodiment of 
a wiring harness B arranged according to the invention and comprising all 
the above-mentioned features for the simple harness A of FIG. 1, but which 
also comprises gas taps 9 connected mechanically, more particularly by 
snap action, to the respective high-voltage units 3 by the rapid 
mechanical connecting means 5 with which said units are provided. Again in 
order to increase reliability and for simplification purposes, the gas 
taps 9 are mechanically connected to the respective high-voltage generator 
units 3 in such manner that each switch is so controlled as to close by 
axial actuation of the shaft of the tap controlling the supply of gas to 
the corresponding burner. 
FIG. 3, in which the same numerical references are used to denote the 
components already shown in FIGS. 1 and 2, diagrammatically illustrates a 
gas burner having the general reference 10. The burner is equipped with an 
electrical ignition element 11, to the bottom of which is secured the 
connection 8 of the corresponding high-voltage line 7 from-the respective 
high-voltage unit 3 of the harness B (this module is visible only in FIG. 
3). The gas tap 9--mechanically connected to the high-voltage unit 3--is 
conventionally fixed on the front panel 12 of the cooker. The projecting 
end of the shaft 13 is provided with an actuating knob 14, behind which is 
disposed the switch 4, the actuating head of which extends freely through 
the front panel 12. 
To operate the burner 10, the knob 14 must first be pushed axially--in 
which position it actuates the switch 4 to close the primary circuit of 
the transformer and provide high-voltage energisation of the ignition 
element 11--and then rotated to control the gas input to the burner, such 
gas igniting on contact with the sparks produced by the ignition element 
11. Once the gas has ignited, the knob, which remains in the rotated 
position, is released and pushed axially forward again by the action of a 
return spring, to free the switch 4 which opens the ignition circuit. 
It will be seen that in the drawings the connection means 6 are disposed at 
locations which simplify the illustration and facilitate the reading of 
the drawings; in practice, these means can be provided at any place on the 
units 3 which is technically most advantageous, e.g. near the front 
surface of the units 3 if it is required to secure free intermediate 
sections of the power supply line mechanically (e.g. by stapling) to the 
front surface of the panel 12. 
It will be apparent and clear from the foregoing that the invention is in 
no way limited to those embodiments which have been considered more 
particularly, on the contrary, it covers all variants.