WO2008148769A2

WO2008148769A2 - A cooking range

Info

Publication number: WO2008148769A2
Application number: PCT/EP2008/056866
Authority: WO
Inventors: Haluk Karatas; Onder Fesligil
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2007-06-04
Filing date: 2008-06-04
Publication date: 2008-12-11
Anticipated expiration: 2009-12-04
Also published as: WO2008148769A3

Abstract

The present invention relates to a cooking range (1) comprising an upper panel (2) preferably produced of glass or ceramic, at least one heater (3) arranged underneath the upper panel (2), a lower panel (4) preferably made of sheet metal disposed below the upper panel (2) for defining a closed volume wherein the heater (3), electrical and mechanical elements and the connections are contained, and one or more springs (5) secured on the lower panel (4) connected to the heater (3) so that the heater (3) abuts against the upper panel (2) for maintaining a full surface contact.

Description

A COOKING RANGE

[0001] The present invention relates to a vitroceramic cooking range.

[0002] In cooking ranges, particularly in the vitroceramic type cooking ranges, one or more heaters are provided. The heaters are mounted by welding or securing by means of helical or leaf springs on a lower panel, preferably produced of sheet metal. The heaters should entirely abut against the upper panel thereabove, that are preferably made of glass so that heat loss is prevented, however cannot adhere to the upper panel since the temperature is high. Therefore, pressure is applied on the upper panel by means of the springs disposed on the lower panel. The heater is symmetrically attached to the lower panel by at least two springs in order to apply an even pressure on the upper panel.

[0003] As the heaters (H) operate, the cooking range (O) and thus the lower panel (A) are heated. By the effect of heating, the lower panel (A) made of sheet metal sags due to the weight of the heater (H), the spring etc. elements thereon. As a result of this sagging, the full surface contact of the heaters (H) with the upper panel (U) fails and entire or regional gaps are formed between the upper panel (U) and the heaters (H). These gaps bring about losses in transfer of heat to the upper panel (U) and hence to the cooking pot causing the cooking range (O) performance to fall. Moreover, the heat that cannot be transferred to the upper panel (U) due to these gaps, increases the temperature between the upper panel (U) and lower panel (A) and this causes the electrical and mechanical elements in between the panels (A and U) to be damaged.

[0004] In state of the art United States of America Patent No US5847364, the safe mounting system of the heating elements is explained.

[0005] In state of the art Great Britain Patent No GB2114731 a cooking appliance is cited comprising a heater wherein the spring clip member on the lower panel is placed on the projection around the radiant ring for supporting and thereby completing the assembly.

[0006] The aim of the present invention is the realization of a cooking range comprising a lower panel wherein the deformation thereof due to the heat effect is reduced.

[0007] The cooking range realized in order to attain the aim of the present invention, explicated in the first claim and the respective claims thereof, comprises a support made of a shape memory alloy (SMA) secured on the lower panel in the regions that might sag with the effect of heat, that applies a force in the opposite direction of the sagging to oppose the sagging that might form on the lower panel by changing shape with the effect of heat and prevents at least partially the deformation of the lower panel.

[0008] By means of the present invention, the heaters are maintained to entirely abut with the upper panel by preventing the deformation of the lower panel due to effect of high temperatures originating from the long term operation of particularly the vitroceramic cooking ranges. Accordingly, the formation of gaps between the heaters and the upper panel by the deformation of the upper panel due to heat effect and thus the decrease in the cooking range efficiency or the temperature increase of the electrical or mechanical elements are prevented.

[0009] In another embodiment of the present invention, the support can be configured as ring, circular or rectangular. In these embodiments, the sagging is prevented by the contact of the support surface with virtually the entire surface that might sag.

[0010] The cooking range realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

[0011] Figure 1 - is the cross-sectional view of a cooking range in the prior art.

[0012] Figure 2 - is the exploded view of a cooking range.

[0013] Figure 3 - is the schematic view of an embodiment of the present invention.

[0014] Figure 4 - is the view of the X-X cross section in Figure 3.

[0015] Figure 5 - is the schematic view of another embodiment of the present invention.

[0016] Figure 6 - is the schematic view of yet another embodiment of the present invention.

[0017] The elements illustrated in the figures are numbered as follows: 1. Cooking range

2. Upper panel

3. Heater

4. Lower panel

5. Spring

6. Support

[0018] The cooking range (1) of the present invention comprises an upper panel (2) preferably produced of glass or ceramic, at least one heater (3) arranged underneath the upper panel (2), a lower panel (4) preferably made of sheet metal, disposed below the upper panel (2) for defining a closed volume wherein the heater (3), electrical and mechanical elements are contained, and one or more springs (5) secured on the lower panel (4), connected to the heater (3) so that the heater (3) abuts against the upper panel (2) for maintaining a full surface contact (Figure 1).

[0019] The cooking range (1) furthermore comprises a support (6), produced of shape memory alloy, secured on the lower panel (4) in the regions that might be deformed - for example by sagging - that increases the strength against the deformation that might form on the lower panel (4) by changing shape with the effect of heat and prevents at least partially the deformation of the lower panel (4). The support (6) has the material properties of forming a force in the opposite direction to the forces that act on the lower panel (4) at the critical transformation temperature.

[0020] When the heaters (3) are operated, the temperature increases in the volume containing the heaters (3). The strength of the lower panel (4) made of sheet metal decreases with the heat effect. The regions of the lower panel (4) that are affected with the forces applied by the springs (5) and together with the weight of the heater (3) etc. elements secured thereon tend to sag in the direction of gravity. Since the temperature reached simultaneously is also the critical transformation temperature for the shape memory alloy of which the supports (6) are produced, the supports (6) that are secured to the said regions start to change shape. Since the supports (6) are secured on the lower panel (4), they apply a force in the opposite direction of the sag. This force applied by the supports (6) virtually counterbalances the forces causing the sagging, prevents the deformation of the lower panel (4) made of sheet metal and thus the sagging thereof. As a result of preventing sagging of the lower panel (4), the distance between the heaters (3) and the upper panel (2) does not change due to heat effect and thereby not only the efficiency of the cooking range (1) increases but also the electrical and/or mechanical elements positioned between the upper and lower panels (2, 4) are prevented to be affected by the heat.

[0021] In another embodiment of the present invention, the support (6) is configured as a band. In a version related to this embodiment of the present invention, the supports (6) are positioned between the heaters (3) (Figure 2). In another version of this embodiment, the supports (6) are disposed on the diagonal of the lower panel (4), in the region remaining between the heaters (3) (Figure 3 and Figure 4).

[0022] In another embodiment of the present invention, the support (6) is configured to be circular. In this embodiment, the support (6) is mounted on the lower panel (4) such that the center of the circle will coincide with the center of the lower panel (4). Accordingly, an equal force can be applied in the radial direction to all sides.

[0023] In yet another embodiment of the present invention, the support (6) is configured as a ring. In this embodiment, the support (6) is mounted on the lower panel (4) such that the center of the ring will coincide with the center of the lower panel (4) (Figure 5). In another version of this embodiment, the ring shaped supports (6) are fitted into one another to be positioned on the lower panel (4). Accordingly, a lesser amount of material is used as compared with the circle shaped embodiment. Moreover, in the circle shape, the material at the center region can affect to decrease the movement of the shape memory alloy. The ring shaped configuration diminishes this effect.

[0024] In a yet another embodiment of the present invention, the support (6) is shaped quadrangularly. In this embodiment, the diagonals of the support (6) are preferably situated on the diagonals of the lower panel (4) (Figure 6). Thus, a higher strength can be maintained at the corners against sagging in the diagonal direction.

[0025] By each of the three embodiments, the supports (6) are disposed almost entirely onto the surface wherein sagging might form thereby minimizing sagging. The stress distribution on the lower panel (4) is taken into consideration while the supports (6) are positioned.

[0026] In another embodiment of the present invention, the cooking range (1) comprises one or more fixing elements such as screws, rivets, adhesives etc. for securing the support (6) on the lower panel (4). The fixing process is made preferably from the end regions and by point connections, not by holding the support (6) from the entire surface thereof so that the shape changing properties of the shape memory alloy are not decreased. The connection points and the fixing elements are selected according to the stress distribution of the lower panel (4).

[0027] By means of the present invention, the formation of gaps between the upper panel (2) and the heaters (3) abutting against the upper panel (2) is avoided by preventing the lower panel (4) with reduced strength due to heat effect from sagging by the effect of the weights thereon, thereby increasing the cooking range (1) efficiency and obviating the electrical or mechanical elements from being damaged with high temperature by the increase of temperature between the panels (2, 4). The present invention relates to a vitroceramic cooking range.

[0028] In cooking ranges, particularly in the vitroceramic type cooking ranges, one or more heaters are provided. The heaters are mounted by welding or securing by means of helical or leaf springs on a lower panel, preferably produced of sheet metal. The heaters should entirely abut against the upper panel thereabove, that are preferably made of glass so that heat loss is prevented, however cannot adhere to the upper panel since the temperature is high. Therefore, pressure is applied on the upper panel by means of the springs disposed on the lower panel. The heater is symmetrically attached to the lower panel by at least two springs in order to apply an even pressure on the upper panel.

[0029] As the heaters (H) operate, the cooking range (O) and thus the lower panel (A) are heated. By the effect of heating, the lower panel (A) made of sheet metal sags due to the weight of the heater (H), the spring etc. elements thereon. As a result of this sagging, the full surface contact of the heaters (H) with the upper panel (U) fails and entire or regional gaps are formed between the upper panel (U) and the heaters (H). These gaps bring about losses in transfer of heat to the upper panel (U) and hence to the cooking pot causing the cooking range (O) performance to fall. Moreover, the heat that cannot be transferred to the upper panel (U) due to these gaps, increases the temperature between the upper panel (U) and lower panel (A) and this causes the electrical and mechanical elements in between the panels (A and U) to be damaged.

[0030] In state of the art United States of America Patent No US5847364, the safe mounting system of the heating elements is explained.

[0031] In state of the art Great Britain Patent No GB2114731 a cooking appliance is cited comprising a heater wherein the spring clip member on the lower panel is placed on the projection around the radiant ring for supporting and thereby completing the assembly.

[0032] The aim of the present invention is the realization of a cooking range comprising a lower panel wherein the deformation thereof due to the heat effect is reduced.

[0033] The cooking range realized in order to attain the aim of the present invention, explicated in the first claim and the respective claims thereof, comprises a support made of a shape memory alloy (SMA) secured on the lower panel in the regions that might sag with the effect of heat, that applies a force in the opposite direction of the sagging to oppose the sagging that might form on the lower panel by changing shape with the effect of heat and prevents at least partially the deformation of the lower panel.

[0034] By means of the present invention, the heaters are maintained to entirely abut with the upper panel by preventing the deformation of the lower panel due to effect of high temperatures originating from the long term operation of particularly the vitroceramic cooking ranges. Accordingly, the formation of gaps between the heaters and the upper panel by the deformation of the upper panel due to heat effect and thus the decrease in the cooking range efficiency or the temperature increase of the electrical or mechanical elements are prevented. [0035] In another embodiment of the present invention, the support can be configured as ring, circular or rectangular. In these embodiments, the sagging is prevented by the contact of the support surface with virtually the entire surface that might sag. [0036] The cooking range realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

[0037] Figure 1 - is the cross-sectional view of a cooking range in the prior art. [0038] Figure 2 - is the exploded view of a cooking range. [0039] Figure 3 - is the schematic view of an embodiment of the present invention.

[0040] Figure 4 - is the view of the X-X cross section in Figure 3. [0041] Figure 5 - is the schematic view of another embodiment of the present invention. [0042] Figure 6 - is the schematic view of yet another embodiment of the present invention. [0043] The elements illustrated in the figures are numbered as follows:

1. Cooking range

2. Upper panel

3. Heater

4. Lower panel

5. Spring

6. Support

[0044] The cooking range (1) of the present invention comprises an upper panel (2) preferably produced of glass or ceramic, at least one heater (3) arranged underneath the upper panel (2), a lower panel (4) preferably made of sheet metal, disposed below the upper panel (2) for defining a closed volume wherein the heater (3), electrical and mechanical elements are contained, and one or more springs (5) secured on the lower panel (4), connected to the heater (3) so that the heater (3) abuts against the upper panel (2) for maintaining a full surface contact (Figure 1).

[0045] The cooking range (1) furthermore comprises a support (6), produced of shape memory alloy, secured on the lower panel (4) in the regions that might be deformed - for example by sagging - that increases the strength against the deformation that might form on the lower panel (4) by changing shape with the effect of heat and prevents at least partially the deformation of the lower panel (4). The support (6) has the material properties of forming a force in the opposite direction to the forces that act on the lower panel (4) at the critical transformation temperature.

[0046] When the heaters (3) are operated, the temperature increases in the volume containing the heaters (3). The strength of the lower panel (4) made of sheet metal decreases with the heat effect. The regions of the lower panel (4) that are affected with the forces applied by the springs (5) and together with the weight of the heater (3) etc. elements secured thereon tend to sag in the direction of gravity. Since the temperature reached simultaneously is also the critical transformation temperature for the shape memory alloy of which the supports (6) are produced, the supports (6) that are secured to the said regions start to change shape. Since the supports (6) are secured on the lower panel (4), they apply a force in the opposite direction of the sag. This force applied by the supports (6) virtually counterbalances the forces causing the sagging, prevents the deformation of the lower panel (4) made of sheet metal and thus the sagging thereof. As a result of preventing sagging of the lower panel (4), the distance between the heaters (3) and the upper panel (2) does not change due to heat effect and thereby not only the efficiency of the cooking range (1) increases but also the electrical and/or mechanical elements positioned between the upper and lower panels (2, 4) are prevented to be affected by the heat.

[0047] In another embodiment of the present invention, the support (6) is configured as a band. In a version related to this embodiment of the present invention, the supports (6) are positioned between the heaters (3) (Figure 2). In another version of this embodiment, the supports (6) are disposed on the diagonal of the lower panel (4), in the region remaining between the heaters (3) (Figure 3 and Figure 4).

[0048] In another embodiment of the present invention, the support (6) is configured to be circular. In this embodiment, the support (6) is mounted on the lower panel (4) such that the center of the circle will coincide with the center of the lower panel (4). Accordingly, an equal force can be applied in the radial direction to all sides.

[0049] In yet another embodiment of the present invention, the support (6) is configured as a ring. In this embodiment, the support (6) is mounted on the lower panel (4) such that the center of the ring will coincide with the center of the lower panel (4) (Figure 5). In another version of this embodiment, the ring shaped supports (6) are fitted into one another to be positioned on the lower panel (4). Accordingly, a lesser amount of material is used as compared with the circle shaped embodiment. Moreover, in the circle shape, the material at the center region can affect to decrease the movement of the shape memory alloy. The ring shaped configuration diminishes this effect.

[0050] In a yet another embodiment of the present invention, the support (6) is shaped quadrangularly. In this embodiment, the diagonals of the support (6) are preferably situated on the diagonals of the lower panel (4) (Figure 6). Thus, a higher strength can be maintained at the corners against sagging in the diagonal direction.

[0051] By each of the three embodiments, the supports (6) are disposed almost entirely onto the surface wherein sagging might form thereby minimizing sagging. The stress distribution on the lower panel (4) is taken into consideration while the supports (6) are positioned.

[0052] In another embodiment of the present invention, the cooking range (1) comprises one or more fixing elements such as screws, rivets, adhesives etc. for securing the support (6) on the lower panel (4). The fixing process is made preferably from the end regions and by point connections, not by holding the support (6) from the entire surface thereof so that the shape changing properties of the shape memory alloy are not decreased. The connection points and the fixing elements are selected according to the stress distribution of the lower panel (4).

[0053] By means of the present invention, the formation of gaps between the upper panel (2) and the heaters (3) abutting against the upper panel (2) is avoided by preventing the lower panel (4) with reduced strength due to heat effect from sagging by the effect of the weights thereon, thereby increasing the cooking range (1) efficiency and obviating the electrical or mechanical elements from being damaged with high temperature by the increase of temperature between the panels (2, 4).

Claims

1. A cooking range (1) that comprises an upper panel (2) produced of glass or ceramic, at least one heater (3) arranged underneath the upper panel (2), a lower panel (4) preferably made of sheet metal disposed below the upper panel (2) for defining a closed volume wherein the heater (3), electrical and mechanical elements are contained, and one or more springs (5) secured on the lower panel (4) connected to the heater (3) so that the heater (3) abuts against the upper panel (2) for maintaining a full surface contact and characterized by one or more supports (6) produced of shape memory alloy, secured on the lower panel (4) in the regions that might be deformed with the effect of heat during the operation of the heaters (3), that increases strength against the deformation that might form on the lower panel (4) by changing shape with the effect of heat.

2. A cooking range (1) as in Claim 1 , characterized by a support (6) configured as a band.

3. A cooking range (1) as in Claim 1 or 2, characterized by a support (6) that is disposed on the diagonal of the lower panel (4) in the region between the heaters (3).

4. A cooking range (1) as in Claim 1 , 2 or 3, characterized by a support (6) that is positioned on the lower panel (4), on the horizontal and vertical axes passing between the heaters (3)

5. A cooking range (1) as in any one of the above claims, characterized by a support (6) that is configured as a ring.

6. A cooking range (1) as in any one of claims 1 to 4, characterized by a support (6) that is shaped quadrangularly.

7. A cooking range (1) as in any one of claims 1 to 4, characterized by a support (6) that is shaped circularly.

8. A cooking range (1) as in any one of the above claims, characterized by a support (6) that is mounted on the lower panel (4) such that the center thereof corresponds with the center of the lower panel (4).

9. A cooking range (1) as in any one of the above claims, characterized by a support (6) that is positioned on the lower panel (4) by being fitted into one another.