EP0079483A1 - Control device for an electrical cooking plate - Google Patents

Abstract

In addition to its main heating (12) of conventional power, which is manually controlled by a power control device (17), an electric hotplate (11) has an additional heating (13) which is connected in parallel with the main heating (12) and in series with a temperature switch (15) and an additional contact, which is actuated by the setting shaft (21) of the power control element (17) in an upper or middle power range of the hotplate (11). The temperature switch is a relatively slow-acting temperature limiter with a large switching hysteresis, which in this case serves as a timer that normally does not switch on after a single switch-off. Infinitely adjustable clocking power control devices and seven-cycle switches are provided as the power control device (17).

Description

Electric hot plates according to DE-PS 23 10 867 = GB-PS 14 70 296 have a heater, which consists for example of a heating resistor that is controlled by a continuously adjustable, clocked, the power control device. In order to accelerate the boil-up at a preselected continued cooking output, an increased output is released via a time switch contained in the control element, which often works thermally, which is either the full installed output by bridging the power control device or is occasionally also adapted to the particular continued cooking setting. In order to release this parboiling power, a separate switch or push button is actuated or a special handling is carried out on the power setting toggle, for example pushing it in or pulling it out.

It is also generally known in electric hotplates to switch off all or part of the heating by means of a temperature limiter in order, for example if the switch-off has been forgotten, to close the hotplate and its surroundings against the upper temperature. protect.

For reasons of overheating, the performance of conventional electric hotplates is also limited to certain values which depend on the hotplate diameter and e.g. for a hotplate diameter of 145 mm 1000 to 1500 watts, for 180 mm diameter 1500 to 2000 watts and for 220 mm diameter 2000 to 2600 watts (both normal and "hotplate").

From DE-PS 21 18 407, 25 57 133 and 25 57 194 control devices have become known which have temperature switches responsive to different temperatures and thereby partially switch off an initial parboiling performance.

The following publications are also to be observed in connection with the present invention: DE-PS 664 707, 11 23 059, 969 992, 972 839; DE-AS 10 75 761, 11 92 340; DE-OS 15 15 131, 16 15 376, 30 18 416, 25 56 433, 22 21 874, 21 18 407, 28 41 691; GB-PS 10 05 604, 587 953; U.S. Patent 33 64 338, 28 30 164; DE-GM 73 44 499.2; EP-OS 0 031 516 and published German patent application L 18 895.

The object of the invention is to provide an easily and sensibly controllable electric hotplate with increased parboiling power and improved controllability.

This object is achieved by a control device for electric hot plates with at least one consumption heating resistor, the electric hot plate being supplied with increased power in a heating phase via a manually switchable additional switch, which can be switched off via a temperature switch provided on the electric hot plate, in which, according to the invention, the temperature switch is arranged and has such a large switching hysteresis that it is switched off once during the continued loading drive of the electric hotplate in the cooking or roasting area does not switch on again.

According to a preferred embodiment, an additional heating which can be switched off by the temperature switch can be provided in addition to the usual heating, which normally consists of a heating resistor in the case of a stepless power control unit and three heating conductors in the case of a seven-cycle switched plate, which can be activated by a simple manual switching contact. This is preferably on the power setting shaft, so that no additional push buttons or actuators are necessary.

According to DE-PS 11 23 059, which is referred to here, the temperature switch can be constructed very simply and works reliably. Due to a preferred arrangement in the unheated middle zone of the electric hotplate, it has a relatively low and inertial heat coupling to the hotplate, so that it switches off with a certain time delay and does not switch on again during normal cooking or roasting. The switching can vorzu ^g s-wise above 50 K (preferably above 100 K) in the range of 570 K (00 ° C ₃₎ as upper and about 420 K (150 ° C) as the lower response temperature.

In the interaction between the electric hotplate, additional heating and temperature switch, an increased parboiling power is released over a certain time and this is then switched off permanently, since it is ensured that the additional heating is only switched on in the medium to upper power range, i.e. the temperature switch is not switched on during normal cooking and roasting closes again. The automatic heating function that is created in the simplest way is also dependent to a certain extent on the power decrease, ie the fact whether, for example, a large cooking vessel with a lot of cold food has been placed on the electric hotplate or a small cooking vessel with food that is not easy to heat. The greater the decrease in power, the more the heating of the hotplate is delayed and the longer the additional heating remains switched on. In this respect, there is thus a functional advantage over the previously used parboiler circuit, which works quite independently of the hotplate.

It is possible to choose the total power consumption of the electric hotplate, including the additional heating, higher than the power usually assigned to the respective hotplate diameter. You can e.g. With a hotplate of 180 mm diameter, reduce the output of the main heating from 1500 watts to 1200 watts and switch on another 1200 watts as additional heating, so that this hotplate has a maximum output of 2400 watts and therefore boils up extremely quickly. Despite this high output, there is no risk of overheating, since the temperature switch ensures that the additional heating is switched off after the boiling phase. In addition, the hotplate could be protected by a conventional temperature limiter, which then preferably operates with little inertia and with a low switching hysteresis and which can switch off the main heating completely or at least partially.

The control element can be, for example, a clocking power control device which clocks the undivided main heating with a continuously adjustable relative duty cycle. With this arrangement, the invention has particular advantages in that it enables the power to be brought above a certain absolute maximum limit, which is normally of the order of 1800 watts.

If a greater power is controlled by an energy regulator, the limit which is considered to be permissible due to the radio interference emanating from the switch-off processes is normally exceeded. The permissible switch-off frequency could be exceeded, especially with several hotplates. A high output can be achieved by the invention without the power control device having to control the entire installed output.

In this embodiment, it is possible to switch on the additional heating in the next power stage of the control element. The associated toggle position, which is at the end of the power setting range and can be characterized, for example, by a catch in addition to an optical signal, thus represents a "kick-down" position that enables the food to be heated up quickly and automatically after the heating-up phase usually shuts down installed power.

The control member can particularly preferably be a manually actuated multi-stroke switch, preferably a seven-stroke switch, to which a contact is assigned, which switches on the additional heating in addition to the heating resistors forming the main heating. In the case of a seven-cycle plate, an additional heating resistor would be provided in addition to the three main heating resistors, e.g. in an eighth switch position (with the usual toggle gauging from 1 to 3 located beyond the "3" or at "3") creates automatic heating.

However, the invention can not only be used to accelerate the boil-up by a total output that goes beyond the usual level, but also a finer gradation of the power setting is created. When the additional heating is switched on, even in a medium one The power range could be improved, for example, by limiting the power to be controlled by the power control device or a multi-cycle switch, the controllability of very low powers for keeping food warm or the heating of sensitive foods, such as porridge, because there a low power is achieved with a higher relative duty cycle.

In one _'embodiment, the power control means may be that the load current pulsing switching switch contact of a connected in parallel thereto contact of a temperature switch can be bridged, so that when the contact is closed, the consumer heating resistor gets the full power of the electric hotplate, even though the power control means to a lower value is set and, if necessary, has also opened its switching contact. The power control device would continue to operate while the heating phase is running, ie the contact of the temperature switch is still closed. If the control element of the expansion element (bimetal) of the clocking power control device is connected in series with the consumer by means of a current coil, the power control device does not work during this phase, i.e. its contact is also closed because the current coil is not heated and therefore the bimetal does not switch can open. Only after the temperature switch has responded would the normal duty cycle of the power control device begin with an "on phase".

If, as is intended, a voltage coil connected in parallel with the consumer is used, by means of which the number of types can be kept lower, this would be switched on continuously during the heating-up phase in this circuit and thus switch off the power control device. Is the switch is bridged anyway, but overheating of the power control device and, in particular, excessive deflection of the bimetal and thus of the snap switch could occur due to the permanent activation of the control heating.

To avoid this, it is particularly preferred if the switch of the power control device is designed such that, preferably by arranging two separate counter contacts to the switch contact, the control heating is also separated from the line which leads from the power control device to the consumer when the switch is opened. The control heating really only gets voltage when the switch of the power control unit is closed, because the switching spring with its two contacts creates a bridge between the two counter contacts. As a result, the power control unit then works "empty" during the boil-up phase, but this is of no consequence. In any case, there is no overheating or switch override.

This is particularly important if the control heating is preceded by a diode which is effective in the higher power setting range of the power control device and there lowers the power consumption of the control bimetal for the power control device, as is described in DE-AS 26 25 715 (= US 4 206 344), to which express reference is made here. In the lower power setting range, the diode is bridged or ineffective, so that the double bimetal heating power is then present, which would lead even more easily to the phenomena to be feared.

The arrangement of the two contacts on the switch of the power control unit can preferably be carried out by using a simple double snap switch with a snap spring with a free end on which parallel two contacts are arranged side by side, which interact with two fixed, electrically insulated counter-contacts. This ensures that both contacts are switched at exactly the same time, so that there is only one switch-on or switch-off surge in the network. The snap spring can preferably be bifurcated at the free end and an insulating web, which electrically separates the two contacts from one another, can be arranged in the intermediate space.

But it is also possible to use a D ^q ppel snap spring, ie a snap spring that has a support in the central area and contains two free ends with one contact each. Your actuation pressure point is in the middle area. In this version, an exact simultaneous snapping is not ensured with every adjustment, but earlier or later snapping on one side or the other can be deliberately provided in order to switch the control heating of the power control unit earlier or later than the consumer itself. The double snap switch can be constructed as described in DE-PS 24 22 684, to which express reference is made.

It is also possible to design the temperature switch as a changeover switch which switches between the circuit which connects the consumer heating resistor and via the additional contact to the mains and the circuit which contains the power control device and the consumer heating resistor. The control heating of the power control device can also be connected in parallel to the consumer heating resistor there. If, however, the additional contact is only switched on during part of the power range of the power control device, i.e. not always during operation, the auxiliary contact must be assigned an auxiliary contact that is switched in the opposite direction, which ensures that in the switched-off state State of the temperature limiter and the additional contact of the circuit via the power control unit and the consumer heating resistor is closed. In all versions, the additional contact is preferably coupled to the setting shaft in such a way that it is switched on in an upper power range of the power control unit, but remains switched off in power ranges below the normal parboiling power (usually below a quarter of the installed power of the hotplate).

The heating phase is preferably provided in the cooking and roasting area of the power control device, but not in the heating area. The location of these areas depends on the size, type and maximum output of the hotplate. As a guideline, however, one can assume that in the heating range, in which the heating phase is normally not provided, the power setting is so low that the temperature of the food does not rise above 100 ° C (373 K).

Instead of the temperature limiter described above; which does not switch on again due to its large switching hysteresis and thus has a good and sufficient effect with the least manufacturing outlay, any other type of temperature switch can be used as a temperature switch, in particular those which have a switch-off delay. It would also be conceivable to use a temperature switch which, due to a large contact gap on its snap switch, does not spring back into the starting position after the one-time response and is only mechanically brought back to the starting position when the setting shaft is in the zero position.

An advantage of the invention is that it is conventional, usually as an energy regulator _. or power control devices designated power control devices can be used if they are assigned a simple additional contact or switch. This can preferably be done in that the additional contact is contained in an attachment switch housing for the power control device, which is saddled on the operating side of the power control device on its housing and is penetrated by the common setting shaft.

• Fig. 1 bis 4 und 8 schematische Schaltbilder von Ausführungsbeispielen von Steuereinrichtungen mit den zugehörigen Elektrokochplatten und
• Fig. 5 die Draufsicht auf die Schnappfeder des Schalters der Leistungssteuereinrichtung nach Fig. 2,
• Fig. 6 eine bevorzugte Variante von Fig. 3,
• Fig. 7 einen Schnitt nach der Linie V-V in Fig. 4 und
• Fig. 9 eine perspektivische Ansicht einer Steuereinrichtung.

The invention is explained in more detail below with the aid of a few preferred exemplary embodiments. Certain advantageous combinations are shown in the exemplary embodiments. To reduce the number of examples, however, the other combinations of features are not shown and described in detail, although they may also be advantageous. The drawing shows:

• 1 to 4 and 8 are schematic circuit diagrams of exemplary embodiments of control devices with the associated electric hotplates and
• 5 shows the top view of the snap spring of the switch of the power control device according to FIG. 2,
• 6 shows a preferred variant of FIG. 3,
• Fig. 7 is a section along the line VV in Fig. 4 and
• Fig. 9 is a perspective view of a control device.

In the drawing, identical parts have the same reference numerals and comparable or functionally identical parts are additionally provided with a small letter as an index, so that their description is referred to in other embodiments.

Fig. 1 shows an electric hotplate 11 of conventional design with a hotplate body made of cast material, not shown in detail, with an upper flat cooking surface. A main heater 12 is provided, which consists of one or more heating resistors connected in parallel or in series, which are embedded in grooves on the underside of the hotplate body. The invention is very particularly advantageous and in connection with such hot plates, but can also be used with other electric hot plates, such as glass ceramic cooking appliances. The main heater 12 is arranged together with an additional heater 13 in an annular area of the hotplate, which leaves an unheated middle zone 14 free in the middle, in which a temperature switch 15 is arranged. This is a temperature limiter, which has a bimetal and a snap switch 16 actuated thereby in a usually crescent-shaped or crescent-shaped ceramic housing. Because of its crescent shape, the temperature switch 15 can be arranged well in the area of the unheated central zone without covering the normal central bolt for mounting the hob. The main heating 12, as well as the additional heating 13.ggf. revolves in several turns around the hotplate, is connected to the household power network 28 via a power control device 17. The usual clocked power control device 17 has a snap switch 18, a bimetal 19 actuating it and a control heater 20 for the bimetal on, which is connected in series with the switch 18. It is infinitely adjustable via an adjusting shaft 21 from an adjusting knob 22. The setting shaft additionally actuates a switch 23, which can advantageously be closed already at the stage at which the heating range ends and the range of continued cooking performance begins (for example with a 180 mm diameter hotplate from 300 watts). This range begins with a normal scale division on the adjusting knob from 1 to 12 at position 4. The switch 23 is in series with the switch 16 of the temperature switch 15 and the additional heating 13. This branch with the additional heating is therefore parallel to the main heating and the Power control unit switched and electrically independent. The usual mechanical switch contacts for the all-pole disconnection of the hotplate from the mains in the zero position are not shown.

If the output is set in the heating range, the additional heating is switched off, but the adjustability of the smallest outputs is improved. If the power control device e.g. can still safely control a relative duty cycle of 8%, then this is only 96 watts, i.e. 4% of the total output.

When setting a power at which the switch 23 is closed, in addition to the respective partial power of the main heater 12, the entire additional heater 13 is switched on, so that a very quick heating-up process results. Depending on the coupling of the temperature switch 15 to the temperature of the hotplate, the temperature switch 15 will respond in more or less dependence on the power removed after a certain time of, for example, 6 minutes, and the additional heating 13 again switch off. Even if the power is subsequently reduced in order to maintain the cooking state by resetting the power control device, the temperature switch 15 remains switched off, so that the additional heating remains ineffective until the hotplate has been taken out of operation and has largely cooled down. For this function there is a large hysteresis of the tempera- door switch is an advantage. This switching temperature difference between switching off and on again should be over 50 K, preferably over 100 K to 150 K, and makes it possible to use a particularly simple and reliable temperature switch. This can be constructed according to DE-PS 11 23 059, to which reference is made. For the present case, it can have a switch-off temperature of approx. 620 K (350 ° C) and a switch-on temperature of approx. 530 K (260 ° C).

It can be seen that the main heating 12 is protected by an additional temperature limiter 24 with a lower switching hysteresis, which prevents the main heating which is accidentally left on at a higher power level, thermally endangering the hotplate.

Fig. 2 shows a hotplate 11a of the same basic structure, the main heating 12 consists of three individual, some different sized heating resistors, which are connected to a conventional seven-stroke switch 17a shown only as a block and by rotating the adjusting shaft 21a in the usual manner individually, in Can be connected in series and in parallel, so that six power levels can be implemented. Such a seven-stroke switch is in DE-PS 26 04 783 (= _GB - _PS 15 77 852) to which reference is made. With an electric hot plate of 180 mm diameter, for example, the main heating 12a could have 1200 watts in the division 600, 400, 200 watts and the additional heating 1300 watts. This results in the lowest power of only 110 watts, a value that has so far been unrivaled by a high-performance hotplate with a 7-stroke circuit. Even if the power is left in the usual range, e.g. at 2000 watts in the division 1000: 1000 watts, compared to the previous versions, the advantages of quick boiling without switching up and down by the operator and the finer adjustment option over the entire heat remain - and continued cooking area preserved (lowest power below 100 watts). Large hotplates for restaurants can also be improved in use, for example by adding a 300 x 300 mm square hotplate to the 2500 watt, 7-stroke controlled additional heating, which enables rapid heating. In the example shown, one of the resistors of the main heating can be switched off via a temperature limiter 24, which, likewise in FIG. 1, is a low-inertia temperature limiter which is well coupled to the temperature of the heating of the hotplate.

The additional heating 13 is connected in the same way as in FIG. 1 via the temperature switch 15 and the switch 23 in parallel to the branch of the main heating and independently of this. In one case, the switch 23 is closed by the setting shaft 21 or a switching cam arranged thereon, if the switch is set beyond or to the maximum power level of the normal seven-cycle switch. The additional heating then works together with the temperature switch in the described way as automatic boost. In addition, a particularly fine adjustability is achieved if the connection is switched on at one of the upper power levels, advantageously from the beginning of the continued cooking range (with the usual scaling from 1 to 3 from level 2). It can be assumed that these power levels are normally only used for parboiling, since there are hardly any cooking or roasting processes that require the entire power of the main heating as a continuous power. The higher levels for parboiling can be emphasized by appropriate visual delimitation on the setting button.

It can thus be seen that a particularly simple possibility is created here: possibility of increasing the output or reducing the heating time of a hotplate, which also creates an automatic heating function. It is particularly advantageous that the operator can fully integrate it into a single manual setting element for the power and automatic parboiler, so that operation is particularly sensible and simple.

In the embodiment according to FIG. 3, the consumer heating resistor 12 of an electric hotplate 11b is connected in series with the switch 18 of a clocking power control device 17. The control heater 20 is connected in series with the consumer heating resistor 12 in the example shown.

In parallel to the power control device 17, an bypass line 30 is connected, which contains the manually switchable additional switch 23 and the contact 16 of the temperature switch 15, which is normally closed, ie in the lower temperature range. Depending on In the desired mode of operation, the additional contact 23 is closed in all or part, preferably the upper part, of the power setting range of the power control device. If the previously cold hotplate is placed in a power range in which the contact 23 is closed, the power control device 17 is bridged and the control heater 20 remains de-energized despite the then closed switch 18. The total power is thus applied to the hotplate until the temperature switch 15 responds and opens the contact which has been closed until then. Then the full power flows through the consumer heating resistor 12 until the control heater 20 has deflected the expansion member 19 so far that the switch 18 opens. Then the usual clocking mode of operation of the power control unit begins, depending on its power setting. The temperature switch 15 always remains switched off, at least in an upper power range, so that the bridging branch 40 is then ineffective.

In the embodiment of Fig. 4 3 consists in the rest of the same design, the difference in that the power control means 17a comprises a control heater 20a which is connected in parallel to the load heating resistor, that is, voltage and not st _romabh ä _na ig operates as in Fig. The parallel branch 42 containing the control heating is connected to a fixed mating contact 33 of the switch 17a of the power control unit, while the consumer heating resistor is connected to a fixed mating contact 44 which is electrically isolated therefrom. The switch 18a contains two movable contacts 45, 46 which can contact the two fixed mating contacts 43, 44 together and simultaneously.

The procedure is as described in Fig. 3. Here too, when the additional contact 23 is switched on, the power control device 15a is bridged and thus ineffective for the hotplate control until the temperature switch 15 has opened. Since the switch 18a was first closed when the hotplate was switched on, the control heater 20a connected in parallel with the consumer is switched on and actuates the switch 18a after a while via the expansion member 19. When it is switched off, however, the parallel circuit 42 is opened, so that the expansion element 19 then cools down. In this case, the power control device 17a cooperates during the heating phase, but without having an effect on the control of the hotplate. Only when the temperature switch 15 opens is it automatically switched to the power clocked by the power control device.

FIG. 5 shows the top view of the snap spring 30 of the switch 18a according to FIG. 2. It is fastened at one end 31 to a snap switch carrier and connected to a pole. The snap spring 30 made of thin spring material has a bead-shaped groove on which the actuating element, i.e. the expansion member 18 acts and has a spring tongue 33, which is directed from its free end 32 towards the fixed end 30 and is separated by a U-shaped cutout, and is supported on a support bearing 34 of the snap switch carrier which projects through the cutout.

At the free end 32, the two contacts 45, 46 are attached side by side, which cooperate with the two mating contacts 43, 44 when the snap switch is closed. Since the contact pair 43, 45 only the power of the control heater 20a lying in the order of a few watts has to switch, it can be designed much weaker than the contact pair 44, 46.

The embodiment of a snap spring 30a shown in FIGS. 6 and 7 is otherwise identical. Only the end of the snap spring is forked into two mutually parallel sections by an incision 35 into which an insulating web 36 of the housing projects. The relatively flexible sections carrying the contacts ensure that good contact between the two contact pairs is possible even with uneven contact wear.

The embodiment shown in FIG. 8 has a temperature switch 15a, which has a contact 51 acting as a changeover switch. The auxiliary switch 23 is assigned an auxiliary contact 50, which is switched together with the auxiliary switch 23 via the setting shaft 21, but in opposite directions, so that it is opened when the auxiliary contact 23 closes and vice versa. The power control device 17b corresponds to the power control device 17 according to FIG. 3, that is to say has a snap switch 18 with only one contact pair, but the control heater 20a is connected in parallel to the consumer heating resistor 12. The power control device is applied to the changeover contact 51 of the temperature switch 15a, which is therefore closed when the temperature switch has switched off the bypass branch 40 via the additional contact 23 after reaching its switching temperature. The auxiliary contact 50 bridges the temperature switch 15a if the temperature switch has not yet reached its response temperature.

When the cold hotplate 11c is switched on in an area in which the additional switch 23 is closed, the Ver. Consumer heating resistor 12 heated at full power via the bridging branch 40. The power control device 17b is switched off because the temperature switch 15a does not close the changeover contact 51 and the auxiliary contact 50 is also switched off. When the temperature switch 15a is switched over after it has responded, the parallel branch 40 is switched off and the power control device 17b is switched on, which then supplies the power in a clocked manner in a normal manner.

If the hotplate is set in such a way that the additional contact 23 is open, that is to say no boiling-up phase at full power is provided, then the auxiliary contact 50 is closed and ensures that the power control device is effective even when the temperature switch 15a has not yet been switched over. The additional contact 50 can be dispensed with if a parboiling aid is provided over the entire power range of the power control unit 17b, but this is usually not desirable because the resulting initial heating would be too great with very low set powers.

FIG. 9 shows the perspective view of a power control device 17 which is accommodated in a block-like plastic housing with its bimetal heating ventilated by air slots 52. On the remote side 53 remote from the operator there are connecting plugs 54 and possibly a diode. The setting shaft 21 projects through the power control device 17 and a housing 55 for the additional switch 23, which is saddled on the operating side. The flat housing 55 of this additional switch can have a switching cam attached to the setting shaft 21 and the simple spring contact tab trained switch 23 record. The saddling can be done by snapping or screwing onto the housing of the energy regulator 17, and the electrical connections can be made internally directly through plug contacts.

Claims (13)

1. Control device for electric hotplates (11, ac) with at least one consumption heating resistor (12, 12a), the electric hotplate (11) being supplied with an increased output via a manually switchable additional switch (23) in a heating phase, which is via a switch The electric hotplate (11, ac) provided temperature switch (15, 15a) can be switched off, characterized in that the temperature switch (15, 15a) is arranged and has such a large switching hysteresis that it is switched off once during the continued operation of the electric hotplate (11 , ac) does not switch on again in the cooking or roasting area. 2. Control device according to claim 1, characterized in that in addition to that of at least one Heating resistor existing main heater (12, 12a) an additional heater (13) is provided for the electric hotplate (11, 11a), which can be switched on parallel to the main heater (12, 12a) in a medium to upper power range and can be switched off by the temperature switch (15) . 3. Control device according to claim 2, characterized in that the total power consumption of the electric hotplate (11) including the additional heating (13) exceeds the power consumption usually assigned to the respective hotplate diameter. 4. Control device according to claim 2, characterized in that the clocking power-controlled main heating (12, 12a) lies in its power consumption below the power consumption usually assigned to the respective hotplate diameter. 5. Electric hotplate according to claim 2 or 3, characterized in that the control device (17a) contains a manually operable multi-stroke switch, preferably a seven-stroke switch, to which a contact (23) forming the additional switch is assigned, which in addition to the additional heating (13) the heating resistors forming the main heating (12a) switches 6. Control device according to claim 1 for an electric hotplate with a consumer heating resistor (12), which receives the total power of the hotplate (11b), with a clocking power control device, characterized in that the power control device (17, 17a) from that with the temperature switch ( 15) additional switches (23) connected in series, preferably actuatable by the same setting shaft (21) as the power control device (17, 17a), can be bridged. In that the power control means (17,17a) has 7. A control device according to claim 6, characterized in that a parallel to the Verbraucherheizwiderstand (12) connected Steuerbeheizun ^g (20) and that the switch (18a) separate of the power control means (17a) includes two switching contacts (45, 46) for the consumer heating resistor (12) and the control heater (20a), the switch (18a) of the power control device (17a) in particular being a snap switch, the snap fields (30, 30a) of which have two contacts (45, 46), which cooperate with two electrically separated fixed counter-contacts (43, 44), which are preferably arranged next to one another at the free end (32) of the snap spring (30, 30 a), and preferably the end of the snap spring (30 a) is forked and into the resulting space preferably an insulating web (36) engages. 8. Control device according to claim 6 or 7, characterized in that the temperature switch (15a) contains a changeover switch which, when the temperature switch responds from the additional switch (23), contains the current branch (40) to the circuit containing the power control device (17b), wherein Preferably, the auxiliary switch (23) is assigned an auxiliary contact (50) which switches in opposite direction and which switches the power control device (17b) into the consumer circuit when the auxiliary switch (23) is switched off and the temperature switch (15a) is not activated. 9. Control device according to one of the preceding claims, characterized in that the additional switch (23) is contained in an attachment switch housing (35) to the power control device (17) which is saddled on the operating side of the power control device (17) on the housing thereof and is penetrated by a common adjusting shaft (21). 10. Control device according to one of the preceding claims, characterized in that the temperature switch (15) is a slow working temperature limiter with a large switching hysteresis of over 50 ° (50 K), preferably over 100 ° to 150 "(100 to 120 K). 11. Control device according to one of the preceding claims, characterized in that the temperature switch (15) and its temperature-sensitive organ with low heat coupling to the electric hotplate (11) in its unheated central zone (14) is arranged. 12. Control device according to one of the preceding claims, characterized in that the temperature switch (15) is provided in addition to one of the main heating (12, 12a) at least partially assigned, preferably low-inertia temperature limiter (24). 13. Electric hotplate according to one of the preceding claims, characterized in that the additional heating (13) can be switched on from a medium power level as a time-limited heating power.

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