EP3229255B1 - Temperature-dependent switch - Google Patents

Description

The present invention relates to a temperature-dependent switch with a first and a second external connection, the first and second external connection being fixed to an insulator body, the first and second external connection being designed as a first or second connection plate, the two connection plates protruding from the insulator body, and the insulator body is arranged in a housing, having a stationary contact part which is electrically conductively connected to the first external connection, a movable contact part which cooperates with the stationary contact part and is fastened to a spring part which is electrically conductively connected to the second external connection, and which the movable contact part presses against the stationary contact part, a bimetallic part and a plunger arranged between the bimetallic part and the spring part, the bimetallic part exerting compressive forces on the spring part via the plunger when a switching temperature is exceeded and dadu rch the movable contact part lifts off the stationary contact part, and wherein the spring part has a first and a second leg, the movable contact part is fixed to the first leg, the second leg is electrically connected to the second terminal plate, and the plunger between the first leg and the bimetal part is arranged.

Such a switch is from EP 2 511 930 A1 known.

The well-known switch is a temperature protection switch, in which the switching movement of a bimetallic disc transmits compressive forces via a plunger to a current-carrying spring part, which acts as a closing spring here. The closing spring carries a movable contact part which presses it against a stationary contact part when the switch is closed. The stationary contact part and closing spring are each connected to a connecting plate. The two connecting plates are fixed to an insulator body, from which they protrude laterally. The temperature protection switch has a flat housing from which the two connection plates protrude as external connections.

Such temperature-dependent switches are used in a known manner to protect electrical devices from overheating. For this purpose, the switch is electrically connected in series with the device to be protected via its two external connections and is mechanically arranged on the device in such a way that it is thermally connected to it.

In the execution of a switch according to DE 44 28 226 C1 a temperature-dependent switching mechanism consisting of a spring snap-action disc, a bimetallic snap-action disc and a movable contact part is arranged in a housing, which when the switch is closed is in contact with a stationary contact part on the inside of the upper part, which is plated through to a first connection on the upper part on the outside. The conductive lower part serves as the second connection.

The operating current of the device to be protected flows through the two contact parts and the spring snap-in disc into the lower part.

The one from the DE 44 28 226 C1 known switch is provided with a heating resistor which is electrically arranged in series with the external connections and ensures a current-dependent switching function. The operating current of the device to be protected thus flows constantly through this heating resistor, which can be dimensioned in such a way that when a certain operating current is exceeded, it ensures that the bimetallic snap-action disc is heated to a temperature above its response temperature, so that the switch opens at an increased operating current before the device to be protected has overheated.

Below the response temperature of the bimetallic snap-action disc, the circuit is closed and the device to be protected is supplied with power via the switch. If the temperature rises above a permissible value, either as a result of an excessively high operating current or as a result of the device to be protected being overheated, the bimetal snap-action disc deforms, causing the spring snap-action disc to move from its first stable geometric configuration in which it holds the moving contact part presses against the stationary contact part, jumps into its second stable geometric configuration, in which it lifts the movable contact part from the stationary contact part. The switch is opened and the power supply to the device to be protected is interrupted.

The now de-energized device can then cool down again. The switch that is thermally coupled to the device also cools down again and then closes again automatically. While such a switching behavior can make sense to protect e.g. a hair dryer, this is not desirable wherever the device to be protected must not be switched on again automatically after it has been switched off in order to avoid damage. This applies, for example, to electric motors that are used as drive units.

In known temperature-dependent switches, a so-called self-holding resistor is therefore often provided, which is electrically parallel to the connections, as is also the case in DE 44 28 226 C1 is described. When the switch is open, the self-holding resistor is electrically in series with the device to be protected, through which only a harmless residual current flows because of the resistance value of the self-holding resistor. However, this residual current is sufficient to heat up the self-holding resistor to such an extent that it radiates heat that keeps the bimetallic snap-action disk at a temperature above its switching temperature.

Deviating from the design of the switch according to the DE 44 28 226 C1 the temperature-dependent switching mechanism can also only include a bimetallic snap-action disc, which carries the movable contact part and thus carries the operating current.

The rear derailleur can also include a bimetallic spring tongue, as in the DE 198 16 807 A1 is described. At its free end, this bimetallic spring tongue carries a movable contact part which interacts with a stationary mating contact. The stationary mating contact is electrically connected to the first terminal, with the second terminal being electrically connected to the clamped end of the bimetal spring tongue. The bimetallic spring tongue conducts the operating current of the electrical device to be protected.

If the temperature-dependent switch is to carry particularly high currents, a current transmission element in the form of a contact bridge or a contact plate is often used, which is moved by a spring part and carries two contact parts which interact with two stationary mating contacts; see for example the DE 26 44 411 A1 .

In this way, the operating current of the device to be protected flows from the first mating contact via the first contact part into the contact plate, through this to the second contact part and from there into the second mating contact. The spring part is thus de-energized. It is also known to use the spring part itself, for example a bimetal snap-action disc or a spring snap-action disc working against a bimetal part, as a contact bridge which carries the operating current.

The known switches must be able to reliably protect motors both in limit operation at maximum permissible power and when the rotor is locked. Two tests are usually carried out to check whether the switch is capable of doing this.

In the so-called heating test, the motor is operated at maximum power, with neither the current flow through the switch nor the heat transferred from the motor to the switch being allowed to open the switch.

In the so-called locked rotor test, on the other hand, the motor is connected to the operating voltage when the rotor is locked, which means that an operating current flows through the motor that is three to five times higher than the usual operating current.

Of course, this high current also leads to heating of the motor and thus to an increase in temperature at the switch. In order to protect the motor from overheating, a good thermal connection between the switch and the motor must be ensured.

In addition to good thermal coupling, the switch must also meet the required number of switching cycles, which should be at least 3,000 for typical requirements as described above.

In order for the switch to be able to carry high operating currents without the bimetal disc being heated to its switching temperature as a result, the generic EP 2 511 930 A1 proposed to increase the distance between the current-carrying closing spring and the bimetal disc by the mechanically interposed plunger.

The bimetallic disc is also arranged in a recess on an outside of the insulator body in order to thermally decouple it from the current-carrying closing spring on the one hand and to enable good thermal coupling of the bimetallic disc to the device to be protected on the other.

The temperature-dependent switching mechanism used in the known switch is in principle constructed like a so-called thermostat switch, which is used to regulate the temperature of a device equipped with it, for example a heating plate to regulate the temperature. Examples of such thermostatic switches can be found in the following intellectual property rights: DE 31 36 312 A1 , DE 196 37 706 A1 , US 3,972,016A , US 4,669,182A , US 5,059,937A and U.S. 2004/0066269 A1 .

The one from the generic EP 2 511 930 A1 known switch thus deviates from the usual structure of a temperature-dependent switch according to DE 44 28 226 C1 off, although it is not designed as a thermostat but as a temperature protection switch.

At the switch according to the EP 2 511 930 A1 A particular disadvantage is that it only withstands a small number of switching cycles at higher operating currents, i.e. it fails early.

Tests on the applicant's premises have shown that the known switch often no longer opens after 300 switching cycles with a current of 35 A flowing through the closing spring in the locked rotor test with 120 VAC because the contact parts were welded together by arcing.

The US 3,931,603A shows a temperature monitor with bimetal snap-action disc, spring washer and contact bridge. A bolt acts between the bimetal snap-action disc and the spring washer, one end of which is attached to the bimetal snap-action disc. The spring washer is located at the other end of the bolt, with a contact bridge being arranged on the bolt between the spring washer and the bimetallic snap-action disk and a compression spring being arranged between the contact bridge and the bimetallic snap-action disk.

Below its switching temperature, the bimetallic snap-action disc presses the bolt in the direction of two stationary mating contacts, against which the contact bridge rests under the force of the compression spring, which is supported on the bimetallic snap-action disc at the other end.

If the temperature of the bimetallic snap-action disc increases, it pulls the bolt away from the two stationary mating contacts, the bolt lifting the contact bridge from the mating contacts so that the switch opens.

The DE 26 25 102 A also shows a temperature-dependent switch with bimetallic snap-action disc, spring snap-action disc and contact bridge, in which a plunger is connected at one end to the spring snap-action disc and at its other end to the contact bridge, which interacts with two stationary mating contacts.

On the side of the spring snap-action disk remote from the plunger, a bimetallic snap-action disk is arranged, which lies loosely below the spring snap-action disk below its switching temperature, so that the switch is closed.

If the temperature of the bimetallic snap-action disc increases, it presses against the plunger and the spring snap-action disc so that the contact bridge lifts off the stationary mating contacts and the spring snap-action disc snaps from its first to its second mechanically stable position. In this open condition, both the spring-loaded snap disk and the bi-metal snap-action disk push the contact bridge away from the stationary mating contacts.

A switching plunger is provided above the contact bridge and is arranged on an actuating button via a second bistable spring snap-action disk. When the actuating button is pressed into the housing of the switch, the switching plunger presses against the contact bridge when the switch is open. The actuating force of the second spring snap-action disc is less than the sum of the actuating forces of the first spring snap-action disc and the bimetal snap-action disc, so that when the actuating button is pressed into the housing, the second spring snap-action disc snaps into its inactive position when the bimetal Snap disk is above its switching temperature.

If the temperature of the bimetallic snap-action disc drops again, it springs back into its unloaded position, but the contact bridge is held in the open position by the first spring snap-action disc. Pressing the actuating button again now causes the switching plunger to press the contact bridge downwards, so that the first spring snap-action disc snaps back into its first stable position, in which the switch is closed. The actuating force of the second spring snap-action disc must be greater than that of the first spring snap-action disc.

From the US 4,908,596A a temperature-dependent switch is known in which a bimetallic snap-action disc acts via a plunger on a switching arm which carries a movable contact part at its free end which interacts with a stationary counter-contact.

The bimetallic snap disk is secured by a spring washer on a shoulder of the temperature sensitive switch housing. The spring washer enables the bimetal snap-action disc to snap over and dampens the movement of the bimetal snap-action disc during switching processes and is intended to improve the heat exchange between the bimetal snap-action disc and the housing.

From the DE 10 2007 014 237 A1 Among other things, a temperature-dependent switch is known in which a bimetallic disc, when its response temperature is exceeded, exerts a tensile force on a spring arm that presses a movable contact part against a stationary contact, thereby lifting the movable contact part from the stationary contact.

From the GB 1 595 340 A a temperature-dependent switch is known in which a bimetallic disc, when its response temperature is exceeded, exerts a tensile force on a spring arm which presses a movable contact part against a stationary contact, thereby lifting the movable contact part from the stationary contact.

From the US 2013/0057381 A a temperature-dependent switch is known in which a bimetal disc, when its response temperature is exceeded, exerts a compressive force on a spring arm which presses a movable contact part against a stationary contact, thereby lifting the movable contact part from the stationary contact.

From the U.S. 2,309,207A a temperature-dependent switch is known in which a bimetallic disc, below its response temperature, presses a spring arm, which carries a movable contact part, against a stationary contact.

Proceeding from this prior art, it is the object of the present invention to further develop the switch mentioned at the outset in such a way that, with a simple and inexpensive construction, it still provides a sufficient number of switching cycles even with higher switching currents.

According to the invention, this object is achieved with the switch mentioned at the outset in that the tappet is arranged between the spring part and the bimetallic part in such a way that it transmits compressive and tensile forces from the bimetallic part to the spring part.

Because the plunger, in contrast to the known switch, now transmits the movement of the bimetal part to the spring part not only when the switch is opened but also when the switch is closed, the closing speed is increased, which according to the invention is no longer determined only by the spring part, i.e. the closing spring .

The inventors of the present application did not take the suggested route of influencing the formation of the arc itself or redesigning the spring part, but instead increased the switching dynamics of the known switch by providing a forced coupling between the closing spring and the bimetallic part.

This forced coupling is achieved in a structurally simple and inexpensive manner in that the plunger not only transmits a compressive force from the bimetal part to the spring part when opening in a known manner, but also transmits a tensile force from the bimetal part to the spring part when closing.

This measure increases the closing speed of the switch, which, contrary to expectations, already significantly reduces contact wear, especially when switching high currents, which, according to the inventor of the present application, already significantly increases the service life, ie the number of switching cycles.

It is particularly advantageous that the actuating force of the spring part is not increased, but rather an additional closing force is applied by the bimetallic disc. In this way, the opening speed of the switch is not negatively influenced, because when opening, the bimetallic disc only has to overcome the previous closing force of the spring part.

The object on which the invention is based is completely solved in this way.

In this case, it is preferred if the switch comprises a spring snap-in part that transmits compressive and tensile forces to the spring part via the plunger.

The advantage here is that the additional spring snap part not only further increases the closing speed, but also increases the opening speed. When opening, the bimetal part first presses against the spring snap part until it suddenly snaps into its other configuration and works together with the actuating force of the bimetal part against the closing force of the spring part and opens the switch quickly.

This measure is unusual in that the known switch already has a spring part which, in a known manner, counteracts the force of the bimetallic part is working. According to the invention, a spring snap part is now additionally provided in order to further increase the dynamics of the switching process.

As a result, the new switch withstands the required number of switching cycles even with high switching currents.

In the context of the present invention, a “spring snap-in part” is understood to be a spring part that has two stable geometric configurations, as is generally known for spring snap-in disks in temperature-dependent switches. The spring snap part is pushed by the bimetallic part from one of its geometrically stable configurations in the direction of the other until the spring snap part suddenly snaps over completely.

The switch can each be provided with a heating resistor for defined current-dependent switching and optionally also with a self-holding resistor so that the open switch does not cool down and closes again automatically.

It is preferred if the spring snap part and the bimetallic part are arranged at a first end of the plunger and the spring part at a second end of the plunger, the plunger preferably having a shank which has a tapered section at its first end, the opposite the tapered section carries a head that is widened, the bimetal part and optionally the spring snap-in part with their respective through hole being arranged on the tapered section in such a way that the bimetal part and the optionally provided spring snap-in part are held with play between the head and the shaft, and more preferably the tappet has a shank which has a tapered portion at its second end, which carries a head which is widened relative to the tapered portion, the spring part having a through hole being arranged on the tapered portion in such a way that the spring part has play between the head and the shaft is held.

These measures are constructively advantageous. They ensure in a simple way that the spring part, bimetal part and spring snap-in part are fastened to the plunger in such a way that tensile and compressive forces can be transmitted between them.

The tapered portion may be integrally formed with the head or the shank, either by inserting the tapered portion into a blind hole provided in the well, or by fitting the head over the tapered portion. The head can also be designed as a rivet, the bolt of which is inserted into a blind hole provided in the tapered section.

It is also preferred if the bimetal part is designed as an elongated tongue which is arranged on its opposite narrow sides between two abutments which are opposite one another in the longitudinal direction of the plunger, more preferably the spring snap-in part is designed as an elongated tongue which is arranged on its opposite narrow sides in each case is arranged between two abutments which are opposite one another in the longitudinal direction of the plunger, more preferably the bimetal part is designed as a bimetal disc which is arranged at its edge between two abutments which are opposite one another in the longitudinal direction of the plunger, more preferably the spring snap-in part is a spring Snap disk is formed, which is arranged at its edge between two abutments, which are opposite in the longitudinal direction of the plunger.

These measures relate to the possible configurations of the spring snap-in part and the bimetallic part as an elongated tongue or disc. In the context of the present invention, a “disk” is understood to mean a generally round, circular, oval or rounded part.

It is preferred if the housing has an upper side and an underside that are connected to one another via narrow sides, and the housing has an opening on one of its narrow sides and is plugged onto the insulator body with this opening, more preferably the two legs for interrupting a conductive connection between the two connection plates of the ram are bent apart, more preferably the second leg rests against the second connection plate, more preferably the insulator body is composed of two part-bodies, and the two connection plates lie between the two part-bodies.

Furthermore, it is preferred if the bimetal part is arranged in a depression on an outside of the insulator body, more preferably the spring snap-in part is arranged in a depression on an outside of the insulator body, and finally a ring inserted from the outside is provided in the depression, which acts as an abutment is used for the spring snap part and/or the bimetallic part

These measures are structurally advantageous, they lead to a compact, inexpensive switch.

Against this background, the present invention also relates to a switch of the type mentioned at the outset, which has a spring snap-in part that presses the plunger against the spring part at least when the switching temperature is exceeded.

The spring snap-in part and the bimetallic part are preferably arranged at a first end of the plunger and the spring part is arranged at a second end of the plunger, with the spring snap-in part and the bimetallic part preferably being connected to the plunger in such a way that they transmit compressive and tensile forces to the plunger, More preferably, the plunger has a shaft which has a tapered section at its first end, which carries a head that is widened compared to the tapered section, the bimetal part and the spring snap-in part with their respective through hole being arranged on the tapered section in such a way that the bimetal part and the spring catch are held with play between the head and the shaft.

Like the forced coupling of the tappet on both sides discussed above, these measures also lead to improved switching dynamics, so that the number of switching cycles is increased.

In this case, it is preferred if the bimetal part is arranged between the plunger and the spring snap-in part.

The advantage here is that the spring snap part is on the outside of the bimetal part and protects it.

Alternatively, it is preferred if the spring snap part is arranged between the plunger and the bimetallic part.

On the one hand, it is advantageous here that the external bimetallic part can be thermally well coupled to a device to be protected, it being also advantageous that even without forced coupling between the plunger and the bimetallic part as well as the spring snap-in part, the bimetallic part can retain the spring snap-in part lying above it in the direction of the plunger Opening the switch causes it to snap very quickly.

Further advantages result from the description and the attached drawing.

Fig. 1

einen schematischen, nicht maßstabsgetreuen Längsschnitt durch ein erstes Ausführungsbeispiel eines temperaturabhängigen Schalters, bei dem in einem Schaltwerk ein bewegliches Kontaktteil mit einem stationären Kontaktteil zusammenwirkt, und bei dem zwischen einem Bimetallteil und einem Federteil ein Stößel angeordnet ist;

Fig. 2

in einer schematischen Explosionsdarstellung einen Schalter, der das Schaltwerk aus Fig. 1 verwendet;

Fig. 3

den zusammengebauten Schalter aus Fig. 2 in einem Längsschnitt;

Fig. 4

den Schalter aus Fig. 3 in Draufsicht, jedoch ohne Gehäuse;

Fig. 5

in einer Darstellung wie Fig. 1 ein zweites Ausführungsbeispiel für den temperaturabhängigen Schalter; und

Fig. 6

in einer Darstellung wie Fig. 1 ein drittes Ausführungsbeispiel für den temperaturabhängigen Schalter.

Exemplary embodiments of the invention are shown in the attached drawing and are explained in more detail in the following description. Show it:

1

a schematic longitudinal section, not true to scale, through a first exemplary embodiment of a temperature-dependent switch in which a movable contact part interacts with a stationary contact part in a switching mechanism, and in which a plunger is arranged between a bimetal part and a spring part;

2

in a schematic exploded view a switch that turns off the rear derailleur 1 used;

3

the assembled switch 2 in a longitudinal section;

4

the switch off 3 in top view, but without housing;

figure 5

in a representation like 1 a second embodiment for the temperature-dependent switch; and

6

in a representation like 1 a third embodiment for the temperature-dependent switch.

In 1 shows a first exemplary embodiment of a very schematically illustrated temperature-dependent switch 10, which comprises a first and a second external connection 11, 12 and a switching mechanism 14, which establishes or opens an electrically conductive connection between the external connections 11, 12 depending on the temperature.

The switching mechanism 14 comprises a stationary contact part 15 which is electrically conductively connected to the first external connection 11 and a movable contact part 16 which interacts with the stationary contact part 15 and is attached to a spring part 17 which is electrically conductively connected to the second external connection 12 and acts as a closing spring , which presses the movable contact part 16 against the stationary contact part 15.

In this simplified exemplary embodiment, the spring part 17 is designed as a leaf spring which is fixed in the region of the second external connection 12 to a diagrammatically illustrated insulator body 18 to which the first external connection 11 and the stationary contact part 15 are also fixed.

The switching mechanism 14 further comprises a bimetal part 19 and a plunger 21 arranged between the bimetal part 19 and the spring part 17. The spring part 17 and the bimetal part 19 are arranged at opposite ends 20a and 20b of the plunger 21.

In a manner known per se, the bimetallic part 19 presses the plunger 21 against the spring part 17 when a switching temperature is exceeded and thereby lifts the movable contact part 16 from the stationary contact part 15 .

The bimetallic part 19 is designed in the embodiment shown as an elongated tongue, which is arranged on its opposite narrow sides 22 and 23 with sufficient mechanical play for snapping between two opposite abutments 25, 26 in the longitudinal direction 24 of the plunger 21. The upper abutments 25 are part of the insulator body 18, while the lower abutments 26 are designed as a fastening ring for the bimetal part 19.

The plunger 21 is connected to the spring part 17 and the bimetallic part 19 via an upper head 27 and a lower head 28 in tension and compression. A tapered section 31 is provided between a shaft 29 of the plunger 21 and the lower head 28, on which the bimetallic part 17 sits with play. The spring part 17 can also be fixed to the plunger 21 with play. The head 27 and the head 28 are made wider than the tapered section 31 and the shaft 29, respectively.

The shank 29 of the plunger is guided in a through hole 30 arranged in the insulating part 18 in order to protect it from tilting and/or jamming.

in the in 1 switching state shown, the switch 10 is closed. The spring part 17 presses the movable contact part 16 onto the stationary contact part 15 so that the circuit is closed between the two external terminals 11, 12 and the operating current of a device to be protected flows through the spring part 17.

The narrow sides 22, 23 of the bimetal part, which is in its first geometric configuration, rest against the upper abutments 25 and thus support the closing pressure with which the movable contact part 16 is pressed onto the stationary contact part 15.

When its switching or response temperature is exceeded, the bimetal part 17 folds over into its other geometric configuration in such a way that the narrow sides 22, 23 come into contact with the lower abutment 26, so that the bimetal part 17 pushes the plunger 21 in 1 up along the arrow 32 presses. As a result, the plunger 21 pushes the spring part 17 upwards so that the movable contact part 16 is lifted off the stationary contact part 15 and the circuit is opened.

If the temperature of the bimetal part 19 drops again, it jumps back into its first geometric configuration, which is shown in 1 is shown. It exerts a downward tensile force on the spring part 17 via the plunger along the arrow 32, as a result of which the closing speed at which the movable contact part 16 is placed back onto the stationary contact part 15 is increased compared to a design of the switching mechanism 14 in which the bimetal part 19 exerts only a compressive force on the spring part 17.

Parallel to the bimetal part 19, a spring snap-in part 33, also designed as an elongated tongue, is arranged at the end 20b of the plunger 21, the opposite narrow sides 34 and 35 of which also lie between the abutments 25 and 26 with play. The spring snap-in part also sits with play on the tapered section 31 of the plunger 21, so that it can exert compressive and tensile forces on the spring part 17 via the plunger.

The spring snap-in part 33 can be arranged either between the bimetal part 19 and the plunger 21, or on the side of the bimetal part 19 facing away from the plunger 21, as is shown in FIGS Figures 1 to 5 is shown.

The spring snap part 33 further increases the switching dynamics of the switching mechanism 14 . On the one hand, the closing speed is determined in the manner described above further increased, because when the switch 10 is closed, the spring snap-in part 33 jumps from its one stable configuration, in which the narrow sides 34, 35 bear against the abutments 26, back into its other stable configuration, in which the narrow sides are supported on the abutments 25 . The spring snap part 33 like the bimetallic part 19 exerts a tensile force on the spring part 17 via the plunger 21 .

The switching of the spring snap part 33 between its two stable geometric configurations is triggered by the temperature-dependent switching of the bimetallic part 19 between its two geometric configurations.

Since the spring snap member 33 also exerts a compressive force on the spring member 17 via the plunger 21, the opening speed at which the movable contact member 16 lifts away from the stationary contact member 15 when the switch 10 is opened by snapping the bimetallic member 19 is also increased.

2 shows an exploded view for a specific embodiment of the switch 10 from 1 .

The switch 10 includes a two-part insulator body 18 having an upper part 18a and a lower part 18b. The first external connection 11 is designed as a connection plate 36 which carries the stationary contact part 15 . The second external connection 12 is in the form of a connection plate 37 which is electrically connected to the spring part 17 which here has a first leg 38 to which the movable contact part 16 is fixed.

The spring part 17 also has a second leg 39 which runs parallel to the first leg 38 and has a laterally protruding side wing 41 which comes into contact with the second connecting plate 37 during assembly.

When assembling the switch 10, the connection plates 36, 37 and the spring part 17 on top of them are clamped between the upper part 18a and the lower part 18b of the insulator body 18 in such a way that the connection plates 36, 37 are laterally out protruding from the insulator body 18, as seen in the plan view of the assembled switch 10 in Fig 4 can be seen.

The insulator body 18 is then inserted into an in 2 pushed to recognizable flat housing 42 that has a top 43 and a bottom 44, which are connected to each other via narrow sides 45, wherein the housing has an opening 46 on one of its narrow sides 45 and is plugged with this opening 46 on the insulator body 18, like it in 3 can be seen.

The bimetal part 19 is designed as a bimetal disk 47 and the spring snap-in part 33 as a spring snap-in disk 48 . Both discs have an edge 51 or 52 and are arranged in a recess 53 which is open to the outside and which is arranged on the lower outer side 18c of the lower part 18b, so that they are supported on peripheral abutments 25a or 25b of the lower part 18 b when the Switch 10 is closed.

In the recess 53, a ring 54 is used, which engages over the edges 51, 52 radially inward and forms the abutment 26 on which the bimetallic disc 47 and the spring snap-action disc 48 are supported with their edges 51 and 52, respectively, when they are the Open switch 10.

The edges 51 and 52 are guided with mechanical play between the abutments 25 and 26, so that the bimetallic disc 47 and the spring snap-in disc 48 can expand when they snap from one geometric configuration to the other.

The tappet 21 includes the shaft 29 with the lower tapered section 31, on which the bimetallic disc 47 and the spring snap-in disc 48 with their respective through-hole 55 and 56 are plugged with play.

After assembly, the plunger 21 passes through the through hole 30 formed in the base 18b.

The head 27 has a bolt 57 and the head 28 has a bolt 58 . The bolt 57 sits in an upper blind hole 61 in the shank 29, the bolt 58 in a lower blind hole 62 in the tapered section 31. The heads 27 and 28 are designed to be wider than the bolts 57 and 59 and the shank 29 in diameter.

The first leg 38 has a through hole 63 with which it is arranged on the bolt 57 with play.

In this way, the first leg 38 and the bimetallic disc 47 and the spring snap-in disc 48 are connected to one another under tension and pressure.

If the plunger 21 is pushed upwards when the switch 10 is opened, it bends the two legs 38, 39 of the spring part 17 apart.

In figure 5 is in a second embodiment a switch 10` and in 6 in a third exemplary embodiment, a switch 10" is shown, in each case in a representation as in FIG 1 . The same reference numerals denote identical features with identical properties, so that because of the basic structure and the basic function on the above description of the 1 is referenced.

The switch 10` off figure 5 has only the lower head 28, via which the bimetallic part 19 and the spring snap-in part 33 are connected to the plunger 21 in such a way that they move it along the arrow 32 in figure 5 move up and down as the bimetal member 19 and, as a result, the spring snap member 33 snaps from its respective one to the other geometric configuration.

Although the head 27 is missing, there is no risk of the plunger 21 tilting or jamming because it is guided in the through hole 30 .

The spring part 17 bears against the upper end 20a of the plunger 21, so that when the switch 20a is opened it is pushed upwards very quickly by the combined compressive force of the bimetallic part 19 and the spring part 33.

When the switch 10` is closed, the bimetal part 19 jumps into its in figure 5 shown configuration back and pulls the plunger 21 down. Because the spring snap-in part 33 is also connected to the plunger 21, during this process it is first pressed down where the plunger 21 engages it, until it also snaps into its in figure 5 other stable geometric configuration shown.

The spring member 17 is not actively pulled down by the plunger 17 because the head 27 from 1 is not provided here. Nevertheless, the switch 10' closes faster than a switch without forced coupling between the plunger 21 and the bimetal part 19 and the spring snap part 33, because the plunger 21 is moved downwards so quickly that it does not offer any resistance to the closing movement of the spring part 17.

In the case of the switch 10', both the opening speed and the closing speed are therefore increased compared to a switch in which only one bimetal part 19 is provided, which is also not positively coupled to the plunger 21.

Because the switch 10' does not have the head 27, assembly is also simpler than the switch 10 of FIGS Figures 1 to 4 .

When assembling, the insulator body 18 is first joined together so that the two connection plates 36, 37 and the spring part 17 are clamped between the upper part 18a and the lower part 18b.

The plunger 21 is then captively connected to the bimetal part 19 and the spring snap part 33 via the head 28, and this unit thereafter in 2 inserted from below into the preassembled insulator body 18, ie into the depression 53 in the lower part 18b. The plunger is passed with its upper end 20a through the through-hole 30 and comes into contact with the first leg 38 with its upper end 20a.

At the switch 10" off 6 the lower head 28 is also dispensed with. As a further difference to switches 10 and 10', switch 10" has bimetal part 19 below spring snap-in part 33.

Although both heads 27, 28 are missing, there is no risk here either of the ram 21 tilting or jamming because it is guided in the through-hole 30.

If the temperature of the bimetal part 19 increases beyond its transition temperature, the bimetal part 19 jumps from the in 6 shown low-temperature configuration into its other geometric configuration. In doing so, it presses in the middle of the spring snap-in part 33, which is thereby gradually bent up in its center until it suddenly snaps into its other geometrically stable configuration and, together with the bimetallic part 19, pushes the plunger into 6 suddenly pushed upwards.

The spring part 17 rests against the upper end 20a of the plunger 21, so that when the switch 20a is opened it is also pushed up very quickly here by the combined compressive force of the bimetal part 19 and the spring part 33.

When the switch 10` is closed, the bimetal part 19 jumps into its in 6 shown configuration. The spring part 17 now presses on the spring snap-in part 33 via the plunger 21 and presses it down where the plunger 21 engages it, until it also snaps into its in 6 other stable geometric configuration shown.

In this case, the spring part 17 is not actively pulled down by the plunger 17 because the head 27 is off 1 not provided here either. Nevertheless opens the switch 10` is not only quicker than a switch without a spring snap-in part 33, it can also close quicker if designed accordingly. This faster closing is due to the fact that the bimetallic part 19 is moved downwards so quickly as a result of the spring snap-in part 33 snapping over that it no longer offers any resistance to the plunger 21 when the plunger 21 is pushed all the way down again into its in 6 shown position is moved.

In the case of the switch 10", at least the opening speed is thus increased compared to a switch in which only one bimetal part 19 is provided.

Because the switch 10" does not have the head 27, assembly is simpler than the switch 10 of FIGS Figures 1 to 4 .

First, the insulator body 18 is assembled so that the two connecting plates 36, 37 and the spring part 17 are clamped between the upper part 18a and the lower part 18b.

The plunger 21 is then passed through the through hole 30 with its upper end 20a and comes into contact with the first leg 38 with its upper end 20a.

Claims (16)

1. Temperature-dependent switch having a first and second external terminal (11, 12), wherein the first and second external terminals (11 12) are secured to an insulating body (18), the first and second external terminals (11, 12) being configured as first and second terminal sheets (36, 37), the two terminal sheets (36, 37) project from the insulating body (18) and the insulating body (18) is arranged in a housing (43), having a stationary contact part (15) connected to the first external terminal (11) in an electrically conductive manner, a moveable contact part (16) cooperating with the stationary contact part (15) and secured to a spring element (17), which spring element is connected to the second external terminal (12) in an electrically conductive manner and presses the moveable contact part (16) against the stationary contact part (15), a bimetallic element (19) and a plunger (21) arranged between the bimetallic element (19) and the spring element (17), wherein the bimetallic element (19), upon exceeding of a switching temperature, exerts compressive forces via the plunger (21) on the spring element (17) and thereby lifts the moveable contact part (16) from the stationary contact part (15), and wherein the spring element (17) comprises a first and a second branch (38, 39), the moveable contact part (16) being attached to the first branch (38), the second branch (39) being electrically connected to the second terminal sheet (37), and the plunger (21) being arranged between the first branch (38) and the bimetallic element (19),
   characterized in that the plunger (21) is arranged between the spring element (17) and the bimetallic element (19) in such a way that it transmits compressive and tensile forces from the bimetallic element (19) to the spring element (17).
2. Temperature-dependent switch according to Claim 1, characterized by including a snap-action spring element (33) that transmits compressive and tensile forces via the plunger (21) to the spring element (17).
3. Temperature-dependent switch according to Claim 2, characterized in that the snap-action spring element (33) and the bimetallic element (19) are arranged at a first end (20b) of the plunger (21), and the spring element (17) is arranged at a second end (20a) of the plunger (21).
4. Temperature-dependent switch according to anyone of Claims 1 to 3, characterized in that the plunger (21) comprises a shaft (29) having a reduced-diameter section (31) at its first end (20b), which reduced-diameter section supports a head (28) expanded in relation to the reduced-diameter section (31), wherein the bimetallic element (19) and, if applicable, the snap-action spring element (33) with their respective through-opening (55, 56), are arranged on the reduced-diameter section (31), such that the bimetallic element (19) and, if applicable, the snap-action spring element (33) are held, with clearance, between the head (28) and the shaft (29).
5. Temperature-dependent switch according to Claim 3 or 4, characterized in that the plunger (21) comprises a shaft (29) having a reduced-diameter section (57) at its second end (20a), which reduced-diameter section supports a head (27) expanded in relation to this reduced-diameter section (57), wherein the spring element (17; 38), with a through-opening (63), is arranged on this reduced-diameter section (57) such that the spring element (17) is held, with clearance, between this head (27) and the shaft (29).
6. Temperature-dependent switch according to anyone of Claims 1 to 5, characterized in that the bimetallic element (19) is configured as an elongated tongue, the opposing narrow sides (22, 23) of which are arranged respectively between two abutments (25, 26) opposing each other in the longitudinal direction (24) of the plunger (21).
7. Temperature-dependent switch according to anyone of Claims 2 to 6, characterized in that the snap-action spring element (33) is configured as an elongated tongue, the opposing narrow sides (34, 35) of which are arranged respectively between two abutments (25, 26) opposing each other in the longitudinal direction (24) of the plunger (21).
8. Temperature-dependent switch according to anyone of Claims 1 to 5 or 7, characterized in that the bimetallic element (19) is configured as a bimetallic disc (47), the edge (51) of which is arranged between two abutments (25a, 54) opposing each other in the longitudinal direction (24) of the plunger (21).
9. Temperature-dependent switch according to anyone of Claims 2 to 6 or 8, characterized in that the snap-action spring element (33) is configured as a snap-action spring disc (48), the edge (52) of which is arranged between two abutments (25b, 54) opposing each other in the longitudinal direction (24) of the plunger (21).
10. Temperature-dependent switch according to anyone of Claims 1 to 9, the housing (42) has an upper side (43) and a lower side (44), which are connected to one another by means of narrow sides (45), and the housing is provided with an opening (46) on one of its narrow sides (45), and is fitted onto the insulating body (18) by means of said opening (46).
11. Temperature-dependent switch according to anyone of Claims 1 to 10, characterized in that the two branches (38, 39) are bent away from each other by the plunger (21) for the interruption of a conductive connection between the two terminal sheets (36, 37).
12. Temperature-dependent switch according to anyone of Claims 1 to 11, characterized in that the second branch (39) bears on the second terminal sheet (37).
13. Temperature-dependent switch according to anyone of Claims 1 to 12, characterized in that the insulating body (18) is comprised of two subsections (18a, 18b), and the two terminal sheets 836, 37) are arranged between the two subsections (18a, 18b).
14. Temperature-dependent switch according to anyone of Claims 1 to 13, characterized in that the bimetallic element (19) is arranged in a recess (53) in an outer surface (18c) of the insulating body (18).
15. Temperature-dependent switch according to anyone of Claims 1 to 14, characterized in that the snap-action spring element (33) is arranged in a recess (53) in an outer surface (18c) of the insulating body (18).
16. Temperature-dependent switch according to Claim 14 or 15, characterized in that the recess (53) is provided with an externally-inserted ring (54), which serves as an abutment for the snap-action spring element (33) and/or the bimetallic element (19).

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