A gas cooking appliance with a top cover having a thermoelectric safety device

Abstract

The invention relates to a gas cooking appliance comprising, a burner (2) arranged on a top plate (12); a safety valve (70) mounted on the top plate (12) adjacent to the burner (2); a gas safety tap (4) adapted on the top plate (12) to regulate the gas flow delivered to the burner (2), said tap being configured to shut off the gas flow if the supplied electrical signal is interrupted; a gas cut-off switch (60) arranged to interrupt the supply signal so as to close the gas flow in a safety mode; and a top cover (20) rotatably attached at its lower edge to the rear side of the top plate (12) by means of a hinge (22). As the top cover (20) moves toward the top plate (12), a trigger element (30) engages at a predetermined closing angle (a). Once engaged, a cover switch (40) transmits a current that generates a cut-off signal on a cut-off line (62), causing the gas cut-off switch (60) to enter a safety mode.

Description

[0001] A GAS COOKING APPLIANCE WITH A TOP COVER HAVING A THERMOELECTRIC SAFETY DEVICE

[0002] TECHNICAL FIELD

[0003] The present invention relates to a gas cooking appliance, particularly, a gas cooking appliance having a hinged top cover that closes over a top plate on which at least one gas burner is arranged.

[0004] STATE OF THE ART

[0005] In a domestic gas cooking appliance, a flat-form cooktop is provided with one or more gas burners, and each gas burner is surrounded by a support grate. A cover, generally made of a glass or metal sheet, is arranged so as to completely cover the cooktop, resting in a closed position on the support grate for protection when not in use, by means of respective hinges near the rear corners of the top plate.

[0006] Each gas burner (or burners) is connected to a gas distribution pipe, and a gas valve is configured together with a corresponding rotary control element located near the front side of the cooking appliance’s housing so as to regulate the gas flow being supplied to the burner. Household gas cooking appliances, especially cooktops, are typically equipped with thermoelectric safety devices controlling the gas valves of the gas burners. A thermoelectric safety device includes a safety valve mounted on the top plate adjacent to the burner; as long as the burner is lit and producing heat, this valve keeps an electrical circuit closed, thereby allowing gas to flow. If the gas is cut off and the safety valve no longer senses heat, the circuit opens and a gas safety component blocks the gas tap, cutting off the gas flow. This ensures gas safety.

[0007] GB2267335 discloses a multifunctional valve in which the push-button controls for ignition and extinguishing a burner act on switches provided in the energizing circuits of the gas-inlet solenoid valve and the thermocouple circuit respectively. Gas entering the inlet supplies gas to the pilot light and the main burner. During ignition, the button is pressed so that the switch is in the dotted position. This operates the solenoid and allows gas to pass to the pilot light. Also, the igniter is operated via the ignition device. When the pilot light is lit, the thermocouple activates the magnet assembly to keep the obturator open. Releasing the button moves the switch so that the solenoid is operated, allowing gas to pass to the burner. Pressing the button deactivates the magnet so that the obturator closes gas to the pilot light and the burner.

[0008] BRIEF SUMMARY OF THE INVENTION

[0009] The object of the present invention is to provide a new thermoelectric safety device for gas cooking appliances.

[0010] To achieve above objective, the invention relates to a gas cooking appliance comprising, a burner provided on a top plate; a safety valve mounted on the top plate adjacent to the burner; a gas safety tap adapted on the top plate so as to regulate the gas flow delivered to the burner, said tap being set to shut off the gas flow when the supplied electrical signal is interrupted; a gas cut-off switch configured to cut off the supply signal so as to close the gas flow in a safety mode; and a top cover rotatably mounted at its lower edge to the rear side of the top plate by means of a hinge. The gas cooking appliance further comprises a trigger element that is activated at a predetermined closing angle as the top cover moves toward the top plate, and a cover switch configured to send a current that creates a cut-off signal on a cut-off line when the trigger element is activated, thereby causing the gas cut-off switch to enter a safety mode. In this manner, if the top cover starts to close in any situation while the cooking appliance is operating, the gas flow to the burner is cut off at the designated angle, interrupting combustion and ensuring safety. Similarly, the burner cannot be activated by the tap unless the top cover is opened.

[0011] Preferably, the trigger element comprises a pin extending outward from the top plate, arranged such that, when the top cover reaches its closing angle, the downward force applied by the top cover advances the pin and pushes the actuator of the adjacent cover switch via a pusher portion. This way, the pin is pressed by the weight of the cover itself, activating the cover switch without needing any additional force.

[0012] Preferably, the pin is positioned near the cover hinge. This allows precise control of the closing angle via the hinge’s rotation. Moreover, placing the pin along the rear edge of the top plate keeps it out of the user’s workspace.

[0013] Preferably, the cover hinge has a tab arranged to press down on the top of the pin at the closing angle. This provides a compact structure, allowing the pin to be arranged alongside the hinge. Additionally, the high torque applied to the hinge by the weight of the top cover directly translates into a downward load on the pin, thereby actuating the cover switch.

[0014] Preferably, the pin is configured to move vertically, extending perpendicular to the top plate. This allows for easy mounting of the pin onto the top plate and ensures minimal frictional contact during the cover’s rotation.

[0015] Preferably, a biasing spring is arranged beneath the pusher portion, configured to push the pin upward when the top cover is opened, returning it to its initial position. Thus, once the top cover is re-opened, the pin automatically resets itself under the bias of the spring, also resetting the cover switch.

[0016] Preferably, a housing encloses the trigger element and the cover switch in a single assembly. This prevents greasy vapors and other external factors produced during cooking from coming into contact with the cover switch.

[0017] Preferably, the burner is provided with an adjacent safety valve, and the gas cut-off switch includes a cut-off line that is connected on the one side to the safety valve’s supply line and on the other side to the tap. This arrangement allows for easy integration of the top cover thermoelectric safety device into existing cooktops equipped with flame-failure safety.

[0018] In a preferred configuration, a power supply receives the cut-off signal from the cover switch via an input end, then transfers it from an output end to the gas cut-off switch along a trigger line via a MOSFET circuit on the cut-off line. When the cover switch sends the cut-off signal, the MOSFET interrupts the safety valve’s signal, and the gas safety tap enters the safety mode, cutting off the gas. In this way, the thermoelectric safety system provides both flame failure safety and top cover safety using a single wiring setup.

[0019] A preferred application of the invention is an operating method for a gas cooking appliance as described above. This method comprises the steps of igniting the air-gas mixture supplied to the burner from the tap in a normal operation mode; allowing current from the safety valve’s supply line to pass through the gas cut-off switch on the cut-off line to the gas safety tap, thereby keeping the tap open; rotating the top cover on the hinge toward the top plate in a safety mode; when the top cover reaches the closing angle, triggering the cover switch via the trigger element to send a cut-off signal to the power supply’s input end; from the power supply’s output end, feeding the cut-off signal to the gas cut-off switch along the cut-off line via the MOSFET circuit; causing the gas cut-off switch to interrupt the current from the safety valve on the cut-off line, thereby stopping the gas flow from the tap to the burner.

[0020] SHORT DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a perspective view of a representative application of the household gas cooking appliance forming the subject of the invention, shown as a standalone gas cooktop with its top cover in the open position.

[0022] Figure 2 is a perspective and enlarged sectional view illustrating the transition of the gas cooking appliance shown in Figure 1 to a safety mode with the top cover at a 45-degree angle.

[0023] Figure 3 is a perspective view of a representative configuration of a top cover switch used in the gas cooking appliance of the invention, shown in its mounted state.

[0024] Figure 4 is an exploded view of the top cover switch shown in Figure 3.

[0025] Figure 5 is a schematic representation of the thermoelectric safety device in the gas cooking appliance according to the invention.

[0026] DETAILED DESCRIPTION

[0027] In this detailed description, the developed invention is described by way of references to examples so as to better illustrate the subject matter, without implying any limitation.

[0028] Referring to Figure 1 , a standalone cooker is shown, comprising an oven (1 ) beneath a cooktop (10) on which four burners (2) are arrayed on a generally planar top plate (12). At the rear edge of the top plate (12), a top cover (20) is present in a vertical open position. The top cover (20) is composed of a panel (28) sized to fully cover the top plate (12) and a profile- structured panel holder (26) that substantially grips the lower edge of the panel (28). Each of the opposing ends of the panel holder (26) fits in a corresponding hinge (22), allowing rotation about facing points. An inward-facing flexible bumper (24) is adhered near the upper inside portion of the panel (28). Around each burner (2) on the top plate (12) is a metal support grate (14). In the enlarged view, a cylindrical pin (32) is shown passing through an opening formed on the top surface of the rear portion of the top plate (12). The pin (32) is adjacent to the interior side of the panel holder (26). The top cover (20) is open, with the panel (28) oriented at a 90-degree angle relative to the top plate (12), allowing user access to the burners (2).

[0029] In Figure 2, the top cover (20) is shown in a partially closed position, forming a 45-degree angle with the top plate (12). Under its own weight, it rotates on the hinge axis (22) toward the top plate (12). The enlarged sectional illustration shows the trigger element (30) extending from below the top plate (12) into a housing. The hinge (22) is circular and fits tightly into its corresponding opening on the panel holder (26). A radial tab (23) protrudes outwardly from the circular hinge (22) due to a difference in diameter. In this embodiment, the closing angle (a) is 45 degrees, though angles less than 90 degrees are also possible, preferably up to 45 degrees maximum. At the 45-degree angle, the tab (23) presses down on the top of the pin (32). The panel holder (26) forms a slight inward bend from the circular hinge (22). Thus, when the panel (28) reaches the closing angle (a), the lower end of the panel holder (26) aligns vertically, reducing stresses from the panel’s (28) weight.

[0030] Figure 3 shows the top cover switch (40) engaged by the trigger element (30) in perspective, in an assembled state. The cover switch (40) comprises a box-shaped housing (31 ) and a cover (36) partially covering one open side of the housing (31). The housing (31) is box-like. A channel is formed on the upper part of the cover (36), through which a cable (43) connected to the cover switch (40) is routed. The trigger element is a cylindrical stepped rod. The pin (32) is the upper free end of this stepped rod, projecting upward from the housing (31). Below that, inside the housing (31), the pusher portion (34) of the stepped rod narrows from top to bottom in a conical manner. A helical biasing spring (37) is wound around a narrowed lower portion (35) at the bottom of the pusher portion (34), bearing against its upper end. As shown in Figure 4, flexible tabs and adjacent fixed pins protrude outwardly inside the housing (31) to serve as mounting elements (311 ). An opening (312) on the flat top surface of the housing (31 ) guides the linear travel of the pin (32). The cover switch (40) is a typical microswitch structure with an actuator (42) protruding from one side and flat metallic terminals (44) at the bottom. An electrical cable (43) is connected to the terminal (44) to transmit the electrical signal. Within the housing (31 ) and the cover (36), the stepped metal rod forming the pin (32), pusher portion (34), and lower portion (35) is compactly assembled together with the cover switch (40), with the pusher portion (34) positioned directly above the actuator (42). As shown in Figure 2, when the panel (28) of the top cover (20) reaches the closing angle (a), the hinge’s (22) tab (23) presses downward from above onto the pin (32), causing it to move downward through the opening in the top plate (12). The downward stroke of the pin (32) aligns the pusher portion (34) with the actuator (42). Thus, the cover switch (40) is activated, and the current sent by cable (43) completes the circuit upon returning. As depicted in Figure 5, once the cover switch (40) is actuated, electrical current is transferred from a connection end (46) to a power supply (50). The power supply (50) feeds current through a line (51) and also delivers it to the cover switch (40) via one of the cables (43). The returning current passes from an input end (52) of the power supply (50) to an output end (54) and then travels along a trigger line (64) to a gas cut-off switch (60). The gas cut-off switch (60) has a T-like form and is composed of a MOSFET circuit. A cut-off line (62) enters along the vertical stem of the T, while the other branches are connected to the gas safety tap (4) and the safety valve (70) (which works on a thermocouple principle). In general, the built-in gas safety mechanism (not illustrated but widely known) in the tap (4) supplies current through a supply line (61) to the safety valve (70), returning it via the cut-off line (62). As long as this circuit remains closed, the tap supplies gas. However, when the actuator (42) of the cover switch (40) is pressed by the trigger element (30), the current from the power supply (50) is fed through the cover switch (40) back to the input end (52). It then exits from the output end (54), enters the MOSFET circuit on the cut-off line (62), and thereby interrupts the current flowing through the cut-off line (62). Without current, the tap (4) engages its magnetic lock, shutting off the gas flow.

[0031] REFERENCE NUMERALS

[0032] 1 Oven

[0033] 2 Burner

[0034] 4 Tap (gas safety tap)

[0035] 10 Cooktop

[0036] 12 Top plate

[0037] 14 Support grate

[0038] 20 Top cover

[0039] 21 Outer edge

[0040] 22 Hinge

[0041] 23 Tab (hinge projection)

[0042] 24 Bumper

[0043] 26 Panel holder

[0044] 28 Panel

[0045] 30 Trigger element

[0046] 31 Housing

[0047] 311 Mounting element

[0048] 312 Opening 32 Pin

[0049] 34 Pusher portion

[0050] 35 Lower portion

[0051] 36 Cover (of switch housing)

[0052] 361 Cable channel

[0053] 37 Biasing spring

[0054] 40 Cover switch

[0055] 42 Actuator

[0056] 43 Cable

[0057] 44 Terminal

[0058] 46 Connection end

[0059] 50 Power supply

[0060] 51 Line

[0061] 52 Input end

[0062] 54 Output end

[0063] 60 Gas cut-off switch

[0064] 61 Supply line

[0065] 62 Cut-off line

[0066] 64 Trigger line

[0067] 70 Safety valve a Closing angle

Claims

CLAIMS1. A gas cooking appliance comprising, a burner (2) arranged on a top plate (12); a safety valve (70) mounted on the top plate (12) adjacent to the burner (2); a gas safety tap (4) adapted on the top plate (12) to regulate the gas flow delivered to the burner (2), said tap being configured to shut off the gas flow if the supplied electrical signal is interrupted; a gas cut-off switch (60) that interrupts the supply signal so as to close the gas flow in a safety mode; and a top cover (20) rotatably attached at its lower edge to the rear side of the top plate (12) by means of a hinge (22) characterized in that a trigger element (30) set for being activated at a predetermined closing angle (a) as the top cover (20) moves toward the top plate (12), and a cover switch (40) arranged to transmit a current that creates a cut-off signal on a cut-off line (62) when the trigger element (30) is engaged, thereby causing the gas cut-off switch (60) to enter a safety mode.

2. The gas cooking appliance according to Claim 1 , wherein the trigger element (30) comprises a pin (32) extending outward from the top plate (12), such that when the top cover (20) reaches the closing angle (a), it advances under the pressure applied by the top cover (20) and pushes the actuator (42) of the adjacent cover switch (40) via a pusher portion (34).

3. The gas cooking appliance according to Claim 2, wherein the pin (32) is arranged adjacent to the cover hinge (22).

4. The gas cooking appliance according to Claim 3, wherein the cover hinge (22) comprises a tab (23) arranged to apply a downward pressure on the pin (32) at the closing angle (a).

5. The gas cooking appliance according to any one of Claims 2 to 4, wherein the pin (32) is configured for vertical movement, extending perpendicular to the top plate (12).

6. The gas cooking appliance according to any one of Claims 2 to 5, wherein a biasing spring (37) is provided beneath the pusher portion (34), arranged to push the pin (32) upward toward its initial position when the top cover (20) is opened.

7. The gas cooking appliance according to any one of the preceding claims, wherein both the trigger element (30) and the cover switch (40) are mounted together in a housing (31 ).

8. The gas cooking appliance according to any one of the preceding claims, wherein the burner (2) is provided with an adjacent safety valve (70), and the gas cut-off switch (60) includes a cut-off line (62) connected on one side to the safety valve (70) supply line (61 ) and on the other side to the tap (4).

9. The gas cooking appliance according to Claim 8, wherein a power supply (50) receives a cut-off signal from the cover switch (40) at an input end (52) and delivers it from an output end (54) to the gas cut-off switch (60) on the cut-off line (62) via a MOSFET circuit along a trigger line (64).

10. An operating method for the gas cooking appliance according to Claim 9, comprising the steps of igniting the air-gas mixture supplied from the tap (4) to the burner (2) in a normal operation mode; conveying current from the safety valve (70) supply line (61) through the gas cut-off switch (60) via the cut-off line (62) to the gas safety tap (4), thereby keeping it open; rotating the top cover (20) on the hinge (22) toward the top plate (12) in a safety mode; when the top cover (20) reaches the closing angle (a), activating the cover switch (40) via the trigger element (30), thereby feeding a cut-off signal from the cover switch (40) to the input end (52) of the power supply (50); delivering the cut-off signal to the gas cut-off switch (60) via the MOSFET circuit on the cut-off line (62) from the output end (54) of the power supply (50); and causing the gas cut-off switch (60) to interrupt the current from the safety valve (70) on the cut-off line (62), so that the gas safety tap (4) cuts off the gas flow to the burner (2).

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