EP4258316A2 - Temperature-dependent switch - Google Patents

Abstract

Temperature-dependent switch (10, which has a first and a second stationary contact (48, 50) and a temperature-dependent switching mechanism (14) with a movable contact member (42), the switching mechanism (14) counteracting the contact member (42) in its first switching position presses the first contact (48) and thereby establishes an electrically conductive connection between the two contacts (48, 50) via the contact member (42) and in its second switching position keeps the contact member (42) at a distance from the first contact (48) and thus interrupts the electrically conductive connection between the two contacts (48, 50) and opens the switch (10). The switch (10) also has a closing lock (52) which prevents the opened switch (10) from closing again, in which it holds the switching mechanism (14) in its second switching position as soon as it is activated. The closing lock (52) has a locking element (54) which is at least partially made of a shape memory alloy and has an opening (56) through which the movable contact member (42) protrudes through. The locking element (54) is designed to change its shape when a locking element switching temperature is exceeded from a first shape in which the locking element (54) does not activate the closing lock (52) to a second shape in which the locking element (54 ) the closing lock (52) is activated by exerting a force on a part of the rear derailleur (14), which holds the rear derailleur (14) in its second switching position.

Description

The present invention relates to a temperature-dependent switch which has a first and a second stationary contact and a temperature-dependent switching mechanism with a movable contact member. In its first switching position, the switching mechanism presses the contact member against the first contact and thereby establishes an electrically conductive connection between the two contacts via the contact member. In its second switching position, the switching mechanism keeps the contact member at a distance from the first contact and thus interrupts the electrically conductive connection between the two contacts. The temperature-dependent switching mechanism has a temperature-dependent snap part which, when a switching temperature is exceeded, snaps from its geometric low-temperature configuration into its geometric high-temperature configuration and when a switch-back temperature is subsequently undershot, it snaps back from its geometric high-temperature configuration back into its geometric low-temperature configuration. Snapping the temperature-dependent snap part from its geometric low-temperature configuration to its geometric high-temperature configuration brings the switching mechanism from its first switching position to its second switching position and thus opens the switch. In the switch according to the invention, a closing lock is also provided, which prevents the opened switch from closing again by holding the switching mechanism in its second switching position as soon as it is activated.

A generic switch is already available DE 10 2018 100 890 B3 known.

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 and its supply voltage and is mechanically arranged on the device in such a way that it is in thermal connection with it.

A temperature-dependent switching mechanism ensures that the two stationary contacts of the switch are electrically connected to each other below the response temperature of the switching mechanism are connected. The circuit is therefore closed below the response temperature and the load current of the device to be protected can flow via the switch.

If the temperature increases above a permissible value, the switching mechanism lifts the movable contact member away from the counter contact, which opens the switch and interrupts the load current of the device to be protected. The now de-energized device can then cool down again. The switch that is thermally connected to the device also cools down again and would then actually close again automatically.

With the one from the DE 10 2018 100 890 B3 However, in the known switch, a closing lock ensures that this switch-back does not occur in the cooling position, so that the device to be protected cannot automatically switch on again after it has been switched off. The closing lock mechanically locks the rear derailleur so that the rear derailleur cannot close again after it has been opened once, even if strong shocks or temperature fluctuations occur.

This is a safety function that applies, for example, to electric motors that are used as drive units. This is intended to avoid damage to the device or even injuries to the person using the device.

Due to their switching behavior, switches that do not close again after being opened once are also referred to as one-time switches.

It is understood that "opening" the switch means the interruption of the electrically conductive connection between the two contacts of the switch and not an opening of the switch housing in a mechanical sense.

Another switch of this type is from the DE 10 2013 101 392 A1 known. This switch has a temperature-dependent switching mechanism with a temperature-dependent bimetal snap-action disk and a bistable spring disk that carries a movable contact or a current transmission member. When the bimetal snap disk is on is heated to a temperature above its response temperature, it lifts the contact or the current transmission member against the force of the spring washer from the mating contact or contacts and thereby presses the spring washer into its second stable configuration, in which the switching mechanism is in its high-temperature position.

If the switch and thus the bimetal snap-action disk cool down again, it returns to its low-temperature position. Due to its design, its edge cannot be supported on a counter bearing, so that the spring washer remains in the stable second configuration in which the switch is open.

The switch remains in its open position after being opened once, even if it cools down again. However, tests at the applicant's company have shown that the DE 10 2013 101 392 A1 Known switches close again in the event of strong mechanical shocks, so that in some applications it may not be optimally usable from a safety perspective.

It is also known to provide such temperature-dependent switches with a so-called self-holding resistor, which is connected in parallel to the two mating contacts so that it takes over part of the load current when the switch opens. Ohmic heat is then generated in this self-holding resistor, which is sufficient to keep the snap-action disk above its response temperature.

However, this so-called latching is only active as long as the electrical device is still switched on. As soon as the device is switched off from the supply circuit, no more current flows through the temperature-dependent switch, so that the self-holding function no longer applies. After switching the electrical device back on, the switch would be in the closed state again, so that the device could heat up again, which could lead to consequential damage.

This problem is caused by the... DE 10 2007 042 188 B3 and the DE 10 2013 101 392 A1 Known switches are avoided in which the self-holding function is not implemented electrically, but rather by a bistable spring part that is independent of temperature has two stable geometric configurations, as described in the publications cited above.

In contrast, the snap-action disk is a bistable snap-action disk that assumes either a high-temperature configuration or a low-temperature configuration depending on the temperature.

With those mentioned at the beginning DE 10 2007 042 188 B3 The spring washer is a circular spring snap washer to which the contact member is attached in the middle. The contact member is, for example, a movable contact part which is pressed by the spring snap-action disk against the first stationary contact, which is arranged inside on a cover of the housing of the known switch. With its edge, the spring snap washer presses against an inner bottom of a lower part of the housing, which acts as a second contact. In this way, the self-electrically conductive spring snap disk creates an electrically conductive connection between the two mating contacts.

In its low-temperature position, the bimetal snap-action disk lies loosely on the contact part. If the temperature of the bimetal snap-action disk increases, it switches to its high-temperature position, in which its edge presses against the inside of the upper part of the housing and its center presses on the spring-action snap-action disk in such a way that it moves away from its first position switches to its second stable configuration, whereby the movable contact part is lifted off the stationary contact and the switch is opened.

If the temperature of the switch cools down again, the bimetal snap-action disk returns to its low-temperature position. Its edge comes into contact with the edge of the spring snap disk and its center comes into contact with the upper part of the housing. However, the actuating force of the bimetal snap-action disk is not sufficient to allow the spring-action snap-action disk to return to its first configuration.

Only when the switch cools down significantly does the bimetal snap-action disk bend further, so that it can finally press the edge of the spring-action disk so far down onto the inner bottom of the lower part that the spring-action disk returns to its first configuration and the switch closes again.

The one from the DE 10 2007 042 188 B3 The well-known switch remains open after being opened once until it has cooled down to a temperature below room temperature, for which a cold spray can be used, for example.

Although this switch meets the relevant safety requirements in many applications, it has been found that, in rare cases, the tensioning of the bimetal snap-action disk between the upper part of the housing and the edge of the spring-action disk causes the spring-action disk to spring back unintentionally.

From the DE 10 2013 101 392 A1 It is also known to use a current transmission member, for example in the form of a contact plate, which is carried by the spring snap disk, as a movable contact member. Both stationary contacts are now arranged on the inside of the cover of the housing, with an electrically conductive connection being established between them by contacting the contact plate with these two contacts.

In this switch, the spring snap-action disk is fixed with its edge on the lower part of the housing, while the bimetal snap-action disk is provided between the spring snap-action disk and the inner bottom of the lower part.

Below the response temperature of the bimetal snap-action disk, the spring snap-action disk presses the contact plate against the two stationary contacts. If the bimetal snap-action disk switches to its high-temperature position, its edge presses against the spring snap-action disk and its center pulls the spring-action disk away from the upper part, so that the contact plate comes out of contact with the two mating contacts. To make this geometrically possible, contact plates, Spring snap washer and bimetal snap washer are captively connected to each other by a centrally running rivet.

When the temperature of the bimetal snap-action disk drops again, it jumps back to its low-temperature position, but the spring washer remains in its assumed configuration, since the bimetal snap-action disk lacks a counter bearing for its edge, so that it does not force the current transmission member against the two again can press stationary contacts.

Due to its design, this switch has a self-holding function. However, in rare cases, strong mechanical shocks can cause the spring snap disk to spring back unintentionally.

From the DE 25 44 201 A1 A temperature-dependent switch with a current transmission element designed as a contact bridge is also known, in which the contact bridge is pressed against two stationary mating contacts via a closing spring. Via an actuating bolt, the contact bridge is in contact with a temperature-dependent switching mechanism, which consists of a bimetal snap washer and a spring washer, both of which are clamped at its edge.

Like the one from the DE 10 2007 042 188 B3 known switches, the spring washer and the bimetal snap-action disc are both bistable in this switch, the bimetal snap-action disc is temperature-dependent and the spring washer is temperature-independent.

If the temperature of the bimetal snap-action disk increases, it pushes the spring disk into its second configuration, in which it presses the actuating bolt against the contact bridge and thereby lifts it from the stationary mating contacts against the force of the closing spring.

Even when the bimetal snap-action disk cools down, the spring disk remains in this second configuration and keeps the known switch open against the force of the closing spring.

Pressure can now be exerted on the contact bridge from the outside using a button, so that the spring washer is pushed back into its first stable configuration via the actuating bolt.

In addition to the very complex construction, this switch has the disadvantage that in the open state the spring washer lifts the contact bridge from the mating contacts against the force of the closing spring, so that the spring washer in its second configuration must reliably overcome the force of the closing spring. However, because the closing spring ensures that the contact bridge rests securely on the mating contacts when closed, a spring washer with very high stability is required in the second configuration.

Another switch with three switching positions is available DE 86 25 999 U1 known. In this known switch, a spring tongue clamped on one side is provided, which carries a movable contact part at its free end, which interacts with a fixed counter-contact.

A dome is formed on this spring tongue, which is pressed into its second configuration by a bimetallic plate also attached to the spring tongue, in which it distances the movable contact part from the stationary mating contact.

In this switch, the dome must keep the movable contact part at a distance from the fixed mating contact against the closing force of the spring tongue clamped on one side, so that the dome must apply a high actuating force in its second configuration.

The known switch therefore has the disadvantages already discussed above, namely that high actuating forces have to be overcome, which leads to high manufacturing costs and an unsafe state in the cooling position.

The one mentioned at the beginning DE 10 2018 100 890 B3 The well-known switch has the most mechanically stable closing lock compared to the other switches mentioned. Due to the mechanical locking of the rear derailleur, which is caused by the locking lock, an accidental downshift after the switch has been opened is almost impossible.

However, it has been shown that the DE 10 2018 100 890 B3 known closing lock is relatively complex to manufacture, so that the manufacturing costs of the switch are comparatively high.

Against this background, the present invention is based on the object of developing the switch mentioned at the beginning in such a way that it has an alternative closing lock that is simple and therefore inexpensive to manufacture and yet ensures a safe interruption of the circuit even in the cooling position of the switch and in the event of strong vibrations is guaranteed.

According to the invention, this object is achieved in a switch of the type mentioned in that the closing lock has a locking element which is at least partially made of a shape memory alloy and has an opening through which the movable contact member protrudes, and which is designed to change its shape when exceeded to change a locking element switching temperature from a first form in which the locking element does not activate the closing lock to a second form in which the locking element activates the closing lock by exerting a force on a part of the rear derailleur that the rear derailleur in its second Switch position holds.

The closing lock according to the invention is therefore a temperature-dependent closing lock which is activated when a predefined temperature is reached or exceeded, which is referred to here as the locking element switching temperature. As long as the locking element switching temperature is not reached or exceeded, the closing lock is not activated.

The locking lock uses in particular the temperature-dependent shape change effect (memory effect) of a shape memory alloy. It has a locking element that is at least partially made of such a shape memory alloy. This locking element has an opening through which part of the rear derailleur protrudes.

In particular, the movable contact member of the switching mechanism protrudes through this opening and can move through the opening during the switching movement of the switch without colliding with the locking element. The shape of the opening can be designed in a variety of ways, for example round or square.

According to the invention, the temperature-dependent shape change effect of the shape memory alloy of the blocking element is preferably used as follows: As long as the blocking element switching temperature is not exceeded, the blocking element remains in its first shape. In this first form, the locking element does not exert any force on the rear derailleur. Preferably, the locking element does not touch the rear derailleur at all as long as it has its first shape. The switching function of the rear derailleur, which is caused in particular by the temperature-dependent snap part, is therefore not affected as long as the closing lock is not activated. This is only activated when the blocking element assumes its second shape, which happens when the blocking element switching temperature is exceeded due to the shape memory alloy. In its second form, the locking element exerts a force on part of the rear derailleur. This force holds the rear derailleur in its second switching position and prevents it from shifting back to its first, closed switching position.

As soon as the blocking element switching temperature is reached, the switch remains in its second, open switching position. The closing lock prevents the switch from closing again.

Shape memory alloys can be used to ensure such temperature-dependent changes in the shape of components very easily and reliably. The locking element according to the invention can therefore be produced relatively inexpensively. Otherwise the structure of the switch and the rear derailleur it contains will not be changed has to be added, but only the locking element has to be added to the switch, the implementation of the entire closing lock according to the invention is very simple and cost-effective from a manufacturing perspective. The overall costs of the switch are therefore hardly increased by the closing lock according to the invention.

The above-mentioned task is therefore completely solved.

It should be noted at this point that the terms “open switch” and “closed switch” do not refer to a housing position, but to the electrically conductive connection. The terms have nothing to do with whether a switch housing is open or closed. Rather, these terms refer to whether the electrically conductive connection between the two stationary contacts of the switch is opened or established or closed or interrupted.

Regarding the terminology used here, it should also be noted that, according to the definition according to the invention, the change in shape of the shape memory alloy of the blocking element occurs when the blocking element switching temperature is "exceeded". In principle, the change in shape occurs when the blocking element switching temperature is reached. However, the word "exceeding" is intended to clarify at this point that the change in shape of the blocking element occurs after a warm-up process, i.e. when the blocking element switching temperature is reached, starting from a lower temperature and not during a cooling process when the blocking element switching temperature is reached, starting from a lower temperature higher temperature.

The blocking element can, for example, be set up to change its shape from the first shape to the second shape when the blocking element switching temperature is reached during a warm-up process, but to maintain its second shape when the blocking element switching temperature is subsequently reached again during a cooling process.

The change in shape that the blocking element makes when the blocking element switching temperature is exceeded can be varied. For example, the blocking element can change its shape from a flat or rectilinear cross-sectional shape to a convex or concave cross-sectional shape. It is also conceivable that the blocking element bends in a different way, folds over or expands in one direction when the blocking element switching temperature is reached.

Preferably, the shape memory alloy of the locking element is designed to move the locking element towards the switching mechanism when the locking element switching temperature is reached, to touch it and to exert a pressure force thereon, which holds the switching mechanism in its second switching position. This force exerted by the locking element on the rear derailleur is preferably higher than the force exerted by the temperature-dependent snap part, through which the temperature-dependent snap part in its low-temperature configuration attempts to close the switch, i.e. to bring the rear derailleur into its first switching position.

If the switch is opened after reaching the switching temperature and the closing lock is activated after reaching the locking element switching temperature, the closing lock prevents the switch from closing again, even if its temperature falls below the switch-back temperature again and the temperature-dependent snap part tries to snap back into its geometric low-temperature configuration .

According to a preferred embodiment, the locking element is essentially plate or disk-shaped.

This has the advantage that the locking element and thus the entire closing lock hardly increases the overall height of the switch. The dimensions of the switch and the design of the rear derailleur need little or no adjustment compared to regular switches without a closing lock.

In the present case, “plate-shaped” and “disc-shaped” mean that the length and width of the blocking element is significantly greater than its thickness. While "plate-shaped" when viewed from above, almost any shape is possible for the locking element, "disc-shaped" preferably refers to a circular, oval or elliptical shape of the locking element.

According to a further embodiment, the opening in the blocking element is designed as a through hole.

This has the advantage that such a hole can be produced relatively easily and inexpensively. The locking element can, for example, be manufactured as a type of perforated plate, i.e. a plate with a through hole. Such a locking element can be mounted very easily in the housing of the switch and placed over the movable contact member of the switching mechanism. Preferably, the opening or the through hole is arranged centrally in the blocking element.

Both the locking element and the other structure of the switch can, for example, be designed to be rotationally symmetrical.

In a further embodiment it is provided that the blocking element has at least one slot which penetrates the blocking element and adjoins the opening.

Such a slot has the advantage that the shape change effect can be increased. In other words, the locking element can achieve a greater change in shape with the help of the shape memory alloy with the same amount of force. The at least one slot in the locking element also avoids internal stresses that could otherwise arise due to the change in shape of the locking element caused by the shape memory alloy.

It is preferred that the at least one slot runs in a straight line and extends radially outwards from the opening.

This has the advantage that the locking element can bulge more. Parts of the locking element can unfold or unfold along the slot without major shear forces occurring in the area of the opening.

Particularly preferably, two, three, four or more slots are provided in the locking element, each of which adjoins the opening, runs in a straight line and extends radially outwards from the opening.

According to this embodiment, the slots are introduced into the blocking element in a substantially star shape starting from the hole. Each of these slots preferably penetrates the entire thickness of the locking element. This has the advantage that the slots create individual, separate areas in the locking element, which can bend separately when the locking element switching temperature is reached in order to exert the force required for the closing lock on the switching mechanism separately from one another.

The locking element can represent a type of slotted spring washer or slotted plate spring, which is flat in its first form, i.e. purely disk-shaped, and is curved convexly or concavely in its second form.

In a further embodiment it is provided that the switch has a housing and that the blocking element is attached to the housing with its edge.

Since the opening is preferably arranged centrally in the blocking element, such an edge-side attachment of the blocking element has the advantage that the shape change caused by the shape memory alloy is hardly affected. In addition, the locking element can be fixed to the edge of the housing in a very stable manner.

The locking element is preferably attached to the housing along its entire peripheral edge. The attachment can be force-fitting, form-fitting and/or material-fitting. The locking element is particularly preferred with its peripheral edge in the Housing jammed. Such a fastening can be implemented most cost-effectively in terms of production technology.

It is further preferred that the edge of the blocking element is made of an electrically insulating material or is coated with an electrically insulating material.

For example, a middle or central part of the blocking element can be made from the shape memory alloy, which is connected to an electrically insulating material on its outer circumference. Likewise, the entire blocking element can be made from the shape memory alloy and coated on its peripheral edge with an electrically insulating material, for example plastic. Furthermore, an adhesive film can be applied to the edge or along the circumference of the shape memory alloy in order to electrically insulate the edge of the blocking element. The coating or the adhesive film can be arranged on the blocking element on one side or on both sides (top and bottom).

The electrical insulation of the edge of the blocking element has the advantage that electrical insulation of two housing parts of the switch can be achieved with the help of the blocking element. Since the edge of the blocking element is preferably attached to the housing and parts of the housing have current flowing through it, such insulation also has the advantage that the blocking element itself does not carry any current. This in turn has a positive effect on the functions and service life of the shape memory alloy.

According to a further embodiment, the housing has a lower part closed by an upper part, the locking element resting on a circumferential shoulder arranged in the lower part and being arranged clamped between the lower part and the upper part.

Such an arrangement of the locking element has the advantage that during production it only has to be placed on the shoulder in the lower part and is automatically clamped between the upper part and the lower part when the switch housing is closed and is thus fixed. Typically the lower part has: a raised edge, which is at least partially bent or flanged onto the upper part when the switch housing is closed in order to hold the upper part on the lower part.

Furthermore, it is preferred that the first stationary contact or each of the two stationary contacts is arranged on an inside of the upper part.

This measure is structurally known per se. In the case of the switch, it ensures that when the upper part is mounted on the lower part, the geometrically correct association between the first contact or the first and second contacts with the movable contact member is simultaneously established.

In a further embodiment, it is provided that the locking element is arranged on a first side of the temperature-dependent snap part facing the first contact and is set up, in its second form, to directly or indirectly act on the force that holds the switching mechanism in its second switching position to exercise temperature-dependent snap part.

Considering the temperature-dependent snap part, the blocking element according to this embodiment is arranged on the same side of the snap part as the first contact. As soon as the locking element assumes its second shape when the locking element switching temperature is reached, it presses on the switching mechanism starting from this first side of the temperature-dependent snap part.

Depending on the structure of the rear derailleur, the locking element can either touch the temperature-dependent snap part directly and exert the force directly on it or touch another component of the rear derailleur so that it only exerts the force indirectly on the temperature-dependent snap part. Both cases have the advantage that both a direct force on the temperature-dependent snap part and a direct force on the temperature-independent spring part are possible without any problems, since both components typically have a relatively large area are designed and thus offer large-scale attack options for the force.

In an alternative embodiment, it is provided that the locking element is arranged on a second side of the temperature-dependent snap part facing away from the first contact and is designed to, in its second form, directly or indirectly apply the force that holds the switching mechanism in its second switching position to exercise the contact member.

Viewed from the temperature-dependent snap part, the blocking element in this embodiment is therefore not arranged on the side of the first contact (first side), but on the opposite second side of the temperature-dependent snap part. When the locking element switching temperature is reached, it exerts the force that holds the switching mechanism in its second switching position, preferably directly onto the movable contact member. This has the advantage that the force exerted by the locking element is exerted directly on the part that is to be kept at a distance from the first contact when the closing lock is activated. Since the movable contact element is usually a solid component, there is little risk of the switching mechanism being damaged by the closing lock.

According to a further embodiment, the shape memory alloy of the blocking element is a shape memory alloy with a one-way memory effect.

By using a shape memory alloy with a one-way memory effect, the locking element and thus also the locking lock can be designed to be irreversible. In this case, the switch according to the invention is a so-called one-time switch. The shape memory alloy only allows the locking element to change its shape once. After it has changed its shape from the first shape to the second shape when the blocking element switching temperature is exceeded, cooling again does not cause a new change in shape in such a shape memory alloy with a one-way effect.

Alternatively, the shape memory alloy can be a shape memory alloy with a two-way memory effect, wherein the blocking element is designed to change its shape from the second shape to the first shape when a blocking element switch-back temperature falls below, and wherein the blocking element switch-back temperature is lower than that Blocking element switching temperature is.

The switch is then a switch with a closing lock, which is designed to be reversible and can therefore be released again. Two-way shape memory alloys can, so to speak, remember two shapes, one at high temperature and one at low temperature. With such a two-way shape memory alloy, the blocking element can change its shape from the first shape to the second shape when the blocking element switching temperature is reached and can assume its first shape again during subsequent cooling as soon as the blocking element switch-back temperature is reached.

According to a further embodiment, it is provided that the blocking element switching temperature is the same or higher than the switching temperature of the temperature-dependent snap part.

If the two switching temperatures are chosen to be the same, the closing lock is activated at the same time and the switch opens. However, if the locking element switching temperature is selected to be higher than the switching temperature of the temperature-dependent snap part, the closing lock is only activated after the switch is opened. The circuit is interrupted when the switch is opened. In practice, however, due to the residual heat typically remaining in the device to be protected, the switch usually heats up a little before the cooling process begins. The temperature swings slightly after the switch is opened, which is why it is referred to as the so-called overshoot temperature range. It is therefore possible to set the blocking element switching temperature in this overshoot temperature range.

According to a further embodiment, it is provided that the locking element switch-back temperature is lower than the switch-back temperature of the temperature-dependent snap part.

This has the advantage that when the switch cools down regularly after it has been opened, the closing lock remains activated even when the switch-back temperature of the temperature-dependent snap-on part is reached or falls below. A deactivation of the locking lock (if it is designed to be reversible) can then be carried out, for example, by appropriate cold treatment. For example, the switch can be treated manually using a cold spray, which deactivates the closing lock and closes the switch again.

According to a further embodiment, it is provided that the switching mechanism has a temperature-independent spring part which is connected to the movable contact member, wherein the temperature-dependent snap part acts on the temperature-independent spring part when the switching temperature is exceeded and thereby lifts the movable contact member from the first contact. It is particularly preferred that the spring part is a bistable spring part with two temperature-independent, stable geometric configurations.

If the spring part is designed as a bistable spring washer, it is preferred that the spring washer presses the movable contact member against the first contact in its first stable configuration and keeps the movable contact member at a distance from the first contact in its second stable configuration. This has the advantage that the spring washer causes the closing force and thus the contact pressure between the movable contact member and the first contact when the switch is in the closed state (in the first switching position of the switching mechanism). This mechanically relieves the temperature-dependent snap part, which positively influences its service life and the long-term stability of its response temperature (switching temperature).

If the spring part is designed as a bistable spring washer with two geometric configurations that are stable regardless of temperature, this has the additional advantage that the bistable spring washer keeps the switch in its open state after opening.

The temperature-dependent snap part is preferably designed as a bi- or tri-metal snap disk.

According to a further embodiment, it is preferred that the movable contact member comprises a movable contact part that cooperates with the first contact, and that the spring part cooperates with the second contact, it being further preferred that the spring part is electrically connected over its edge at least in its first geometric configuration is connected to the second contact.

This design is in principle from the DE 10 2018 100 890 B3 , the DE 10 2007 042 188 B3 or the DE 10 2013 101 392 A1 known. This means that the temperature-dependent snap-on part is not subject to current in any position of the switch, but rather that the load current of the electrical device to be protected flows through the spring part.

In an alternative embodiment, the movable contact member comprises a current transmission member that interacts with both stationary contacts.

The advantage here is that the switch can carry significantly higher currents than the one from the DE 10 2007 042 188 B3 well-known switches. The current transmission element arranged on the contact element ensures that the electrical short circuit between the two contacts occurs when the switch is closed, so that not only the temperature-dependent snap part, but also the temperature-independent spring part are no longer subject to the load current flowing through, as is already the case in principle DE 10 2013 101 392 A1 is known.

It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or alone, without departing from the scope of the present invention.

Fig. 1

eine schematische Schnittansicht eines ersten Ausführungsbeispiels des erfindungsgemäßen Schalters in seiner Tieftemperaturstellung;

Fig. 2

eine schematische Schnittansicht des in Fig. 1 gezeigten ersten Ausführungsbeispiels des erfindungsgemäßen Schalters in seiner Hochtemperaturstellung;

Fig. 3

eine schematische Schnittansicht des in Fig. 1 gezeigten ersten Ausführungsbeispiels des erfindungsgemäßen Schalters in seiner Hochtemperaturstellung mit aktivierter Schließsperre;

Fig. 4

eine schematische Schnittansicht eines zweiten Ausführungsbeispiels des erfindungsgemäßen Schalters in seiner Tieftemperaturstellung;

Fig. 5

eine schematische Schnittansicht des in Fig. 4 gezeigten zweiten Ausführungsbeispiels des erfindungsgemäßen Schalters in seiner Hochtemperaturstellung;

Fig. 6

eine schematische Schnittansicht des in Fig. 4 gezeigten zweiten Ausführungsbeispiels des erfindungsgemäßen Schalters in seiner Hochtemperaturstellung mit aktivierter Schließsperre;

Fig. 7

eine schematische Schnittansicht eines dritten Ausführungsbeispiels des erfindungsgemäßen Schalters in seiner Tieftemperaturstellung; und

Fig. 8

eine schematische Draufsicht auf ein Sperrelement gemäß einem Ausführungsbeispiel der vorliegenden Erfindung.

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

Fig. 1

a schematic sectional view of a first embodiment of the switch according to the invention in its low-temperature position;

Fig. 2

a schematic sectional view of the in Fig. 1 shown first embodiment of the switch according to the invention in its high-temperature position;

Fig. 3

a schematic sectional view of the in Fig. 1 shown first embodiment of the switch according to the invention in its high-temperature position with the closing lock activated;

Fig. 4

a schematic sectional view of a second embodiment of the switch according to the invention in its low-temperature position;

Fig. 5

a schematic sectional view of the in Fig. 4 shown second embodiment of the switch according to the invention in its high-temperature position;

Fig. 6

a schematic sectional view of the in Fig. 4 shown second embodiment of the switch according to the invention in its high-temperature position with the closing lock activated;

Fig. 7

a schematic sectional view of a third embodiment of the switch according to the invention in its low-temperature position; and

Fig. 8

a schematic top view of a locking element according to an embodiment of the present invention.

In Fig. 1 a switch 10 is shown in a schematic sectional side view, which is rotationally symmetrical in plan view and preferably has a circular shape.

The switch 10 has a housing 12 in which a temperature-dependent switching mechanism 14 is arranged. The housing 12 includes a pot-like lower part 16 and an upper part 18, which is held on the lower part 16 by a bent or flanged upper edge 20.

In the in Fig. 1 In the exemplary embodiment shown, both the lower part 16 and the upper part 18 are made of an electrically conductive material, preferably metal. The upper part 18 rests on a shoulder 22 formed in the lower part with the interposition of an insulating film 24. The shoulder 22 is designed as a circumferential shoulder and has a substantially circular support surface on which the upper part 18 rests with the insulating film 24 in between.

The insulating film 24 ensures electrical insulation of the upper part 18 from the lower part 16. Likewise, the insulating film 24 also ensures a mechanical seal, which prevents liquids or contaminants from outside entering the interior of the housing.

Since the lower part 16 and the upper part 18 in this exemplary embodiment are each made of electrically conductive material, thermal contact can be established with an electrical device to be protected via their outer surfaces. The outer surfaces also serve as the external electrical connection of the switch 10.

Outside on the upper part 18 can, as in Fig. 1 shown, another insulation layer 26 may be attached.

The rear derailleur 14 has a temperature-independent spring part 28 and a temperature-dependent snap part 30. The spring part 28 is preferably designed as a bistable spring washer. It therefore has two geometric configurations that are stable regardless of temperature. In Fig. 1 their first configuration is shown. The temperature-dependent snap part 30 is preferably designed as a bimetal snap disk. This has two temperature-dependent configurations, a geometric high-temperature configuration and a geometric low-temperature configuration. In the in Fig. 1 In the first switching position of the switching mechanism 14 shown, the temperature-dependent bimetal snap disk 30 is in its geometric low-temperature configuration.

The temperature-independent spring washer 28 rests with its edge 32 on a further circumferential shoulder 34 formed in the lower part 16. In its low-temperature configuration, the temperature-dependent bimetal snap disk 30 can be freely suspended in the housing 12 in such a way that its edge 36 does not touch the housing 12. This has, among other things, the advantage that the closing pressure in the closed state of the switch 10 is generated solely by the spring washer 28. Likewise, when the switch 10 is in the closed state, the current only flows through the spring washer 28, but not through the bimetal snap-action disk 30.

However, the edge 36 of the bimetal snap disk 30 can alternatively also rest on the inner bottom surface 38 of the lower part 16 in its low-temperature configuration. The inner floor surface 38 can do this, as in Fig. 1 indicated by the dashed line 39, be raised laterally. In such a case, the closing pressure of the switch 10 in its closed state would be generated not only by the spring washer 28, but also by the bimetal snap-action disk 30.

With its center 40, the temperature-independent spring washer 28 is fixed to a movable contact member 42 of the switching mechanism 14. The temperature-dependent bimetal snap disk 30 is also fixed to this contact member 42 with its center 44.

The movable contact member 42 has a contact part 46 and a ring 45 which is pressed onto the contact part 46. The ring 45 has a circumferential shoulder 47 on which the bimetal snap disk 30 rests with its center 44. The spring washer 28 is clamped between the ring 45 and the upper, widened section of the contact part 46. In this way, the temperature-dependent switching mechanism 14 is a captive unit consisting of contact member 42, spring washer 28 and bimetal snap washer 30. At When installing the switch 10, the switching mechanism 14 can be inserted directly into the lower part 16 as a unit.

The contact part 46 of the movable contact member 42 works together with a fixed mating contact 48 which is arranged on the inside of the upper part 18. This counter contact 48 is also referred to here as the first stationary contact. The outside of the lower part 16 serves as the second stationary contact 50.

In the in Fig. 1 In the position shown, the switch 10 is in its low-temperature position, in which the spring washer 28 is in its first configuration and the bimetal snap-action disk 30 is in its low-temperature configuration. The spring washer 28 presses the movable contact member 42 against the first stationary contact 48.

In the closed low temperature position of the switch 10 according to Fig. 1 An electrically conductive connection is thus established between the first stationary contact 48 and the second stationary contact 50 via the movable contact member 42 and the spring washer 28.

If the temperature of the device to be protected increases and thus the temperature of the switch 10 and the temperature-dependent bimetal snap disk 30 arranged therein, it snaps from the in Fig. 1 shown low-temperature configuration into its concave high-temperature configuration, which is in Fig. 2 is shown. During this snapping, the bimetal snap disk 30 is supported with its edge 36 on a part of the switch 10, in this case on the edge 32 of the spring washer 28. With its center 44, the snap disk 30 pulls the movable contact member 42 down and lifts it the movable contact member 46 from the first stationary contact 48. As a result, it simultaneously bends the temperature-independent spring washer 28 downwards at its center 40, so that the spring washer 28 moves away from its in Fig. 1 shown, first stable geometric configuration in their in Fig. 2 shown, second geometrically stable configuration snapped around. Fig. 2 shows the high temperature position of the switch 10, in which it is open. The circuit is then interrupted.

If the device to be protected and thus the switch 10 together with the temperature-dependent bimetal snap-action disk 30 then cool down again, the bimetal snap-action disk 30 would actually snap back into its low-temperature configuration when it reaches its switch-back temperature, as shown in Fig. 1 is shown. Then the bimetal snap washer 30 would actually put the spring washer 28 back into its first position Fig. 1 Move back the configuration shown and thus close the switch again. However, this switch-back process can be prevented in the switch 10 according to the invention by a closing lock 52.

The closing lock 52 has a locking element 54 which is designed essentially in the shape of a plate or disk. This locking element 54 is in the in Fig. 1-3 shown first embodiment clamped between the lower part 16 and the upper part 18. More precisely, the locking element 54 is clamped between the circumferential shoulder 22 and the insulating film 24. In addition to this clamping arrangement, the locking element 54 can also be connected to the lower part 16 in a materially bonded manner (e.g. glued, welded or soldered).

An embodiment of the locking element 54 is shown in Fig. 8 shown in a schematic top view. The locking element 54 is at least largely made of a shape memory alloy. This shape memory alloy is designed to change the shape of the blocking element 54 from a first shape to a second shape when a predefined temperature is exceeded, which is referred to here as the blocking element switching temperature. In Fig. 8 the first form of the locking element 54 is shown. This also corresponds to that in Fig. 1 and 2 Shape of the locking element 54 indicated in the schematic section, in which the closing lock 52 is not yet activated.

In its first form, the locking element 54 essentially has the shape of a circular disk. It has an opening 56, which in the exemplary embodiment shown here is designed as a centrally arranged hole. The movable contact member 42 of the switching mechanism 14 projects through the opening 56 (see Fig. 1-3 ). The size of the opening 56 is therefore preferably such that the contact member 42 does not collide with the rear derailleur 14 either in the first switching position of the rear derailleur 14 or during its switching movement. It goes without saying that the opening 56 does this does not necessarily have to be designed as a round hole, but can also have a different shape, for example oval, elliptical or square.

The edge 58 of the locking element 54, with which it is attached to the housing 12, is preferably made of an electrically insulating material or coated with an electrically insulating material. This further improves the electrical insulation between the lower part 16 and the upper part 18. In addition, the stability of the clamping of the locking element 54 in the housing 12 can also be increased.

For example, the base body of the blocking element 54 can be made entirely from the shape memory alloy, which is provided with an adhesive film or plastic coating 60 on the edge 58. This adhesive film or plastic coating 60 is preferably applied to both sides of the base body made of shape memory alloy.

This in Fig. 8 Locking element 54 shown also has four slots 62, which extend in a star shape outwards in the radial direction from the opening 56. The slots 62 extend through the entire thickness of the locking element 54. They are therefore not only introduced into the locking element 54 on the surface, but also cut through it. Starting from the central opening 56, they run outwards in a radial direction, but end in front of the outer edge 58 of the locking element 54.

The slots 62 enable a kind of unfolding of the locking element 54 when the shape memory alloy brings the locking element 54 into its second shape when the locking element switching temperature is reached. The four sectors of the locking element 54, separated from one another by the slots 62, then fold as shown in Fig. 3 shown downwards. The individual sectors of the locking element 54 curve or arch downwards.

In Fig. 3 is the curvature of the locking element 54 in its second form such that it is convex on its top and concave on its underside. Depending on Depending on the type of design of the shape memory alloy, the curvature of the locking element 54 in its second form can also be reversed, so that its top is concave and its underside is convexly curved (similar to the two disks 28, 30 in Fig. 3 ).

Such a temperature-related change in shape can in principle also be carried out with a blocking element made of shape memory alloy without slots 62 or with fewer slots 62. However, the slots 62 help to reduce internal stresses caused by the change in shape of the locking element 54. In addition, the change in shape of the locking element 54 can be increased.

At the in Fig. 1-3 The first exemplary embodiment shown results in the following interaction between the switching mechanism 14 and the closing lock 52 or the associated locking element 54: As long as the switching temperature of the bimetal snap-action disk 30 is not exceeded, the switch remains in its position Fig. 1 closed position shown. When the switching temperature is reached, the bimetal snap disk 30 snaps into place, as already mentioned Fig. 2 shown high temperature configuration and lifts the movable contact member 42 from the first stationary contact 48, whereby the switch 10 is opened and the current flowing through the switch 10 up to that point is interrupted. The locking element switching temperature, i.e. the temperature at which the shape memory alloy brings the locking element 54 into its second shape, is preferably chosen to be slightly higher than the switching temperature of the bimetal snap disk 30. For example, the shape memory alloy of the locking element 54 can be designed such that the locking element -Switching temperature is 5-40 K above the switching temperature of the bimetal snap disk 30. When the switching temperature is reached, the blocking element 54 initially remains in its first form, as shown in Fig. 2 is shown. The locking lock 52 is in the in Fig. 2 The situation shown has not yet been activated.

If the temperature of the switch 10 and thus also the temperature of the blocking element 54 increases further, the shape memory alloy ensures the already mentioned change in shape of the blocking element 54 when the blocking element switching temperature is reached, so that it remains in place Fig. 3 shown, takes the second form. In this second form or configuration, the locking element 54 presses as shown in Fig. 3 shown on the top of the spring washer 28. As a result, the locking element 54 exerts a force on the switching mechanism 14, which acts directly on the spring washer 28 and indirectly on the movable contact member 42. This force holds the rear derailleur 14 in its second switching position. The closing lock 52 is activated.

Even if the switch 10 is now moving from the in Fig. 3 situation shown cools down again, the switching mechanism 14 can no longer be brought into its first switching position as long as the closing lock 52 is activated. If the switch 10 were to cool down below the switch-back temperature, the bimetal snap disk 30 would return to its position Fig. 1 Snap back low temperature configuration shown. However, the switching mechanism 14 would also remain in its second switching position, since the edge 36 of the bimetal snap disk 30 snaps into space, so to speak, without being able to be supported on the housing 12.

Even if the inner floor surface 38 is laterally raised, as shown in Fig. 1-3 is indicated by the dashed line 39, the bimetal snap disk 30 in its low-temperature configuration could be supported with its edge on the housing 12. However, as long as the closing lock 52 is activated, the spring washer 28 would still be pressed downwards by the locking element 54, so that the movable contact member 42 would be spaced from the first stationary contact 48 and the switch 10 would remain open.

In order to be able to effectively prevent accidental closing of the switch 10 when the closing lock 52 is activated, even if the bimetal snap disk 30 can be supported on the housing 12 in its low-temperature configuration, only the spring constant of the locking element 54 has to be higher than the spring constant of the bimetal Snap disk 30.

Depending on the design of the locking element 54, deactivation of the locking lock 52 is either not possible at all or is possible through cold treatment.

In the first case of an irreversible closing lock 52, the switch 10 is a one-time switch. For this purpose, a shape memory alloy with a one-way memory effect is selected for the locking element 54.

Alternatively, by using a shape memory alloy with a two-way memory effect, the closing lock 52 can also be designed to be reversible. In this case, the shape memory alloy of the locking element 54 is designed to change the shape of the locking element 54 when the locking element switch-back temperature falls below that in Fig. 3 shown second form into the in Fig. 1 and 2 to bring back the first form shown. In this case, the locking element 54 can, so to speak, remember both shapes.

The shape memory alloy of the locking element 54 is preferably designed such that the locking element switch-back temperature is lower than the switch-back temperature of the bimetal snap disk 30. For example, the shape memory alloy of the locking element 54 can be designed such that the locking element switch-back temperature is lower than room temperature and for example is located in a temperature range of 0-15 °C. Through appropriate cold treatment, the closing lock 52 can be canceled again, so that the switch 10 is released from the in Fig. 3 switching position shown schematically back to the in Fig. 1 Switch position shown schematically would come.

Fig. 4-6 shows a second exemplary embodiment of the switch 10 according to the invention.

Fig. 4 shows, similar to before Fig. 1 , the switch 10 in its closed position, in which the switching mechanism 14 is in its first switching position, the bimetal snap disk 30 is in its low-temperature configuration and the closing lock 52 is not activated. Fig. 5 shows, similar to before Fig. 2 , the switch 10 is in its open position, in which the switching mechanism 14 is in its second switching position, the bimetal snap disk 30 is in its high-temperature configuration and the closing lock 52 is not activated. Fig. 6 shows, similar to before Fig. 3 , the switch 10 in its open position, in which the switching mechanism 14 is still in its second switching position, but the closing lock 52 is activated.

The switching function and the interaction between the switching mechanism 14 and the locking lock 52 take place in the in Fig. 4-6 The second exemplary embodiment shown is the same as above with regard to in Fig. 1-3 shown first embodiment is mentioned.

In contrast to the first exemplary embodiment, the locking element 54 of the locking lock 52 in the in Fig. 4-6 shown, second embodiment is arranged on the opposite side of the rear derailleur 14. While the locking element 54 in the in Fig. 1-3 shown, first exemplary embodiment of the switch 10 is arranged on the upper side of the switching mechanism 14 facing the first contact 48, the locking element 54 is in the in Fig. 4-6 shown, second embodiment of the switch 10 is arranged on the lower side of the switching mechanism 14 facing away from the first contact 48.

The locking element 54 is clamped between two spacer rings 64, 66. The first spacer ring 64 is arranged on the inner bottom surface 38 of the lower part 16. The locking element 54 rests on this first spacer ring 64. The second spacer ring 66 is arranged on the locking element 54. The bimetal snap disk 30 rests with its edge 36 on the top of the second spacer ring 66.

A further spacer ring 68 is arranged at the point at which the locking element 54 was arranged between the lower part 16 and the upper part 18 according to the first exemplary embodiment. This spacer ring 68 serves as a spacer between the lower part 16 and the upper part 18. Furthermore, the spring washer 28 can be supported from below on this spacer ring 68 when the rear derailleur 14 is in its second switching position (see Fig. 5 and 6 ).

At the in Fig. 4-6 shown, second embodiment of the switch 10, the movable contact member 42 is also designed somewhat differently. In the area of its lower end it has a laterally projecting base 70, the diameter of which is slightly larger than the diameter of the opening 56 provided in the locking element 54. The movable contact member 42 protrudes through the locking element 54 provided Opening 56 through, with the widened base 70 being arranged below the locking element 54.

The locking element 54 is designed in the same way as described above in relation to the in Fig. 1-3 shown, first embodiment is mentioned (see Fig. 8 ). However, in its second form, which it assumes after reaching the blocking element switching temperature, the blocking element 54 now engages directly on the movable contact member 42. The locking element 54 presses, as in Fig. 6 shown from above on the widened base 70, whereby the movable contact member 42 is kept at a distance from the first stationary contact 48. Thus, in this exemplary embodiment, it is not possible to close the switch 10 again as long as the closing lock 52 is activated.

In this exemplary embodiment, too, the closing lock 52 can be designed to be reversible or irreversible, depending on whether a shape memory alloy with a one-way memory effect or a shape memory alloy with a two-way memory effect is used for the shape memory alloy of the locking element 54.

Fig. 7 shows a third embodiment of the switch 10 'according to the invention. The closing lock 52 is designed here in the same way as in Fig. 4-6 switch 10 shown.

Since the interaction between the switching mechanism 14 'and the locking lock 52 in the in Fig. 7 Switch 10 'shown is implemented in the same way as mentioned above, this will not be explicitly discussed again at this point. Likewise, for the sake of simplicity, the switch 10' according to the third exemplary embodiment is only shown in its closed position, in which the switching mechanism 14' is in its first switching position.

The structure of the in Fig. 7 Switch 10' shown is slightly different than the structure of switch 10 according to FIG Fig. 1-6 shown, first two embodiments.

The lower part 16 'is again made of electrically conductive material. The flat upper part 18', on the other hand, is made here from electrically insulating material. It is held on the lower part 16' by the bent edge 20'.

A spacer ring 68' is provided between the upper part 18' and the lower part 16', which keeps the upper part 18' at a distance from the lower part 16'. On its inside, the upper part 18' has a first stationary contact 48' and a second stationary contact 50'. The contacts 48' and 50' are designed as rivets which extend through the upper part 18' and terminate externally in the heads 72, 74 which serve for the external connection of the switch 10'.

The movable contact member 42 'here comprises a current transmission member, which is designed as a contact plate, the top of which is coated in an electrically conductive manner, so that the current transmission member 76 in the in Fig. 7 shown, closed position of the switch 10 rests on the contacts 48 ', 50' and ensures an electrically conductive connection between the contacts 48' and 50'. The current transmission member 76 is connected to the spring washer 28 and the bimetal snap washer 30 via a rivet 78, which is also to be viewed as part of the contact member 42 '. If the switching temperature is exceeded, the bimetal snap disk 30 of the switching mechanism 14', similar to before, ensures that the switching mechanism 14' is brought into its second switching position, in which the current transmission member 76 is kept at a distance from the two contacts 48', 50' and the circuit is therefore interrupted.

A key difference of the in Fig. 7 The switch structure shown can be seen in that, in contrast to that in Fig. 1-6 In the exemplary embodiment of the switch 10 shown here, no current flows either through the spring washer 28 or through the bimetal snap-action disk 30 when the switch 10 is in the closed state. When the switch 10' is in the closed state, this flows only from the first external connection 72 via the first contact 48', the current transmission element 76 and the second contact 50' to the second external connection 74.

The locking element 54 of the locking lock 52 engages the rivet 78 as soon as the locking lock 52 is activated, i.e. as soon as the temperature of the switch 10 'and thus the temperature of the locking element 54 exceeds the locking element switching temperature. This is done on the rivet 78, similar to that in Fig. 4-6 shown, second embodiment, a widened base 70 is provided at its lower end. The locking element 54 engages on this base 70 around the rivet 78 and thus the entire movable one Press the contact member 42 'down and hold the switching mechanism 14' in its second switching position as soon as the closing lock 52 is activated.

In principle, the closing lock 52 can also be used with the switch 10 ', as shown in Fig. 7 is shown schematically, be carried out in the manner in which it is shown in Fig. 1-3 shown, first embodiment of the switch 10 is realized.

A reversible design of the locking lock 52 is also possible in the case in Fig. 7 shown, third embodiment of the switch 10 'also possible.

• (1) Temperaturabhängiger Schalter 10, der einen ersten und einen zweiten stationären Kontakt 48, 50 sowie ein temperaturabhängiges Schaltwerk 14 mit einem beweglichen Kontaktglied 42 aufweist, wobei das Schaltwerk 14 in seiner ersten Schaltstellung das Kontaktglied 42 gegen den ersten Kontakt 48 drückt und dabei über das Kontaktglied 42 eine elektrisch leitende Verbindung zwischen den beiden Kontakten 48, 50 herstellt und in seiner zweiten Schaltstellung das Kontaktglied 42 zu dem ersten Kontakt 48 beabstandet hält und damit die elektrisch leitende Verbindung zwischen den beiden Kontakten 48, 50 unterbricht, wobei das temperaturabhängige Schaltwerk 14 ein temperaturabhängiges Schnappteil 30 aufweist, das bei Überschreiten einer Schalttemperatur aus seiner geometrischen Tieftemperaturkonfiguration in seine geometrische Hochtemperaturkonfiguration umschnappt und bei einem anschließenden Unterschreiten einer Rückschalttemperatur wieder aus seiner geometrischen Hochtemperaturkonfiguration zurück in seine geometrische Tieftemperaturkonfiguration umschnappt, wobei ein Umschnappen des temperaturabhängigen Schnappteils 30 aus seiner geometrischen Tieftemperaturkonfiguration in seine geometrische Hochtemperaturkonfiguration das Schaltwerk 14 aus seiner ersten Schaltstellung in seine zweite Schaltstellung bringt und damit den Schalter 10 öffnet, und wobei eine Schließsperre 52 vorgesehen ist, die ein erneutes Schließen des geöffneten Schalters 10 verhindert, in dem sie das Schaltwerk 14 in dessen zweiter Schaltstellung hält, sobald sie aktiviert ist, wobei die Schließsperre 52 ein Sperrelement 54 aufweist, das zumindest teilweise aus einer Formgedächtnislegierung ist und eine Öffnung 56 hat, durch die das bewegliche Kontaktglied 42 hindurchragt, und das dazu eingerichtet ist, seine Form bei Überschreiten einer Sperrelement-Schalttemperatur von einer ersten Form, in der das Sperrelement 54 die Schließsperre 52 nicht aktiviert, in eine zweite Form zu verändern, in der das Sperrelement 54 die Schließsperre 52 aktiviert, indem es eine Kraft auf ein Teil des Schaltwerks 14 ausübt, die das Schaltwerk 14 in seiner zweiten Schaltstellung hält.
• (2) Schalter nach Ausführungsform 1, wobei das Sperrelement 54 im Wesentlichen platten- oder scheibenförmig ausgestaltet ist.
• (3) Schalter nach Ausführungsform 1 oder 2, wobei die Öffnung 56 als Durchgangsloch ausgestaltet ist.
• (4) Schalter nach einem der Ausführungsformen 1 bis 3, wobei die Öffnung 56 zentral in dem Sperrelement 54 angeordnet ist.
• (5) Schalter nach einem der Ausführungsformen 1 bis 4, wobei in dem Sperrelement 54 mindestens ein Schlitz 62 vorgesehen ist, der an die Öffnung 56 angrenzt.
• (6) Schalter nach Ausführungsform 5, wobei der mindestens eine Schlitz 62 geradlinig verläuft und sich ausgehend von der Öffnung 56 radial nach außen erstreckt.
• (7) Schalter nach einem der Ausführungsformen 1 bis 4, wobei in dem Sperrelement 54 mindestens drei Schlitze 62 vorgesehen sind, die jeweils an die Öffnung 56 angrenzen, geradlinig verlaufen und sich ausgehend von der Öffnung 56 radial nach außen erstrecken.
• (8) Schalter nach einem der Ausführungsformen 1 bis 7, wobei der Schalter 10 ein Gehäuse 12 aufweist, und wobei das Sperrelement 54 mit seinem Rand 58 an dem Gehäuse 12 befestigt ist.
• (9) Schalter nach Ausführungsform 8, wobei der Rand 58 des Sperrelements 54 aus einem elektrisch isolierenden Material 60 ist oder mit einem elektrisch isolierenden Material 60 beschichtet ist.
• (10) Schalter nach Ausführungsform 8 oder 9, wobei das Gehäuse 12 ein von einem Oberteil 18 verschlossenes Unterteil 16 aufweist, und wobei das Sperrelement 54 auf einer im Unterteil 16 angeordneten, umlaufenden Schulter 22 aufliegt und zwischen dem Unterteil 16 und dem Oberteil 18 geklemmt angeordnet ist.
• (11) Schalter nach einem der Ausführungsformen 1 bis 10, wobei das Sperrelement 54 auf einer dem ersten Kontakt 48 zugewandten ersten Seite des temperaturabhängigen Schnappteils 30 angeordnet ist und dazu eingerichtet ist, in seiner zweiten Form die Kraft, die das Schaltwerk 14 in seiner zweiten Schaltstellung hält, unmittelbar oder mittelbar auf das temperaturabhängige Schnappteil 30 auszuüben.
• (12) Schalter nach einem der Ausführungsformen 1 bis 10, wobei das Sperrelement 54 auf einer von dem ersten Kontakt 48 abgewandten zweiten Seite des temperaturabhängigen Schnappteils 30 angeordnet ist und dazu eingerichtet ist, in seiner zweiten Form die Kraft, die das Schaltwerk 14 in seiner zweiten Schaltstellung hält, unmittelbar oder mittelbar auf das Kontaktglied 42 auszuüben.
• (13) Schalter nach einem der Ausführungsformen 1 bis 12, wobei die Formgedächtnislegierung eine Formgedächtnislegierung mit Einweg-Memory-Effekt ist.
• (14) Schalter nach einem der Ausführungsformen 1 bis 12, dass die Formgedächtnislegierung eine Formgedächtnislegierung mit Zweiweg-Memory-Effekt ist, und wobei das Sperrelement 54 dazu eingerichtet ist, seine Form bei Unterschreiten einer Sperrelement-Rückschalttemperatur von der zweiten Form in die erste Form zu verändern, wobei die Sperrelement-Rückschalttemperatur niedriger als die Sperrelement-Schalttemperatur ist.
• (15) Schalter nach einem der Ausführungsformen 1 bis 14, wobei die Sperrelement-Schalttemperatur gleich hoch oder höher ist als die Schalttemperatur des temperaturabhängigen Schnappteils 30).
• (16) Schalter nach Ausführungsform 14, wobei die Sperrelement-Rückschalttemperatur niedriger ist als die Rückschalttemperatur des temperaturabhängigen Schnappteils 30).
• (17). Schalter nach einem der Ausführungsformen 1 bis 16, wobei das Schaltwerk 14 ein temperaturunabhängiges Federteil 28 aufweist, das mit dem beweglichen Kontaktglied 42 verbunden ist, wobei das temperaturabhängige Schnappteil 30 bei Überschreiten der Schalttemperatur auf das Federteil 28 einwirkt und dadurch das bewegliche Kontaktglied 42 von dem ersten Kontakt 48 abhebt.
• (18) Schalter nach einem der Ausführungsformen 1 bis 17, wobei das temperaturabhängige Schnappteil 30 eine Bi- oder Trimetall-Schnappscheibe ist.
• (19) Schalter nach Ausführungsform 17, wobei das bewegliche Kontaktglied 42 ein mit dem ersten Kontakt 48 zusammenwirkendes bewegliches Kontaktteil 46 umfasst, und wobei das Federteil 28 mit dem zweiten Kontakt 50 zusammenwirkt.
• (20) Schalter nach einem der Ausführungsformen 1 bis 19, wobei das bewegliche Kontaktglied 42` ein mit beiden stationären Kontakten 48', 50` zusammenwirkendes Stromübertragungsglied 76 umfasst.

The following is a list of further embodiments:

• (1) Temperature-dependent switch 10, which has a first and a second stationary contact 48, 50 and a temperature-dependent switching mechanism 14 with a movable contact member 42, the switching mechanism 14 in its first switching position pressing the contact member 42 against the first contact 48 and thereby over the contact member 42 establishes an electrically conductive connection between the two contacts 48, 50 and, in its second switching position, keeps the contact member 42 at a distance from the first contact 48 and thus interrupts the electrically conductive connection between the two contacts 48, 50, the temperature-dependent switching mechanism 14 a temperature-dependent snap part 30, which snaps from its geometric low-temperature configuration into its geometric high-temperature configuration when a switching temperature is exceeded and, when a switch-back temperature is subsequently undershot, snaps back from its geometric high-temperature configuration back into its geometric low-temperature configuration, with the temperature-dependent snap part 30 snapping out of its geometric low-temperature configuration in its geometric high-temperature configuration, the switching mechanism 14 moves from its first switching position to its second switching position and thus opens the switch 10, and a closing lock 52 is provided which prevents the opened switch 10 from closing again by moving the switching mechanism 14 into its second position Switch position holds as soon as it is activated, wherein the closing lock 52 has a locking element 54, which is at least partially made of a shape memory alloy and has an opening 56 through which the movable contact member 42 projects, and which is designed to change its shape from a first shape when a locking element switching temperature is exceeded which the locking element 54 does not activate the locking lock 52, into a second form in which the locking element 54 activates the locking lock 52 by exerting a force on a part of the rear derailleur 14, which holds the rear derailleur 14 in its second switching position.
• (2) Switch according to embodiment 1, wherein the locking element 54 is designed essentially in the shape of a plate or disk.
• (3) Switch according to Embodiment 1 or 2, wherein the opening 56 is designed as a through hole.
• (4) Switch according to one of embodiments 1 to 3, wherein the opening 56 is centrally arranged in the locking element 54.
• (5) Switch according to one of embodiments 1 to 4, wherein in the locking element 54 at least one slot 62 is provided which adjoins the opening 56.
• (6) Switch according to embodiment 5, wherein the at least one slot 62 is rectilinear and extends radially outward from the opening 56.
• (7) Switch according to one of embodiments 1 to 4, wherein at least three slots 62 are provided in the locking element 54, each of which adjoins the opening 56, runs in a straight line and extends radially outwards from the opening 56.
• (8) Switch according to one of embodiments 1 to 7, wherein the switch 10 has a housing 12, and wherein the locking element 54 is attached to the housing 12 with its edge 58.
• (9) Switch according to Embodiment 8, wherein the edge 58 of the blocking element 54 is made of an electrically insulating material 60 or is coated with an electrically insulating material 60.
• (10) Switch according to embodiment 8 or 9, wherein the housing 12 has a lower part 16 closed by an upper part 18, and the locking element 54 rests on a circumferential shoulder 22 arranged in the lower part 16 and is clamped between the lower part 16 and the upper part 18 is arranged.
• (11) Switch according to one of embodiments 1 to 10, wherein the blocking element 54 is arranged on a first side of the temperature-dependent snap part 30 facing the first contact 48 and is designed to, in its second form, the force that the switching mechanism 14 in its second Switch position holds, directly or indirectly on the temperature-dependent snap part 30.
• (12) Switch according to one of embodiments 1 to 10, wherein the blocking element 54 is arranged on a second side of the temperature-dependent snap part 30 facing away from the first contact 48 and is designed to, in its second form, the force that the switching mechanism 14 has in its holds the second switching position, directly or indirectly on the contact member 42.
• (13) The switch according to any one of embodiments 1 to 12, wherein the shape memory alloy is a shape memory alloy with a one-way memory effect.
• (14) Switch according to one of embodiments 1 to 12, in that the shape memory alloy is a shape memory alloy with a two-way memory effect, and wherein the locking element 54 is designed to change its shape from the second shape to the first shape when a locking element switch-back temperature falls below to change, whereby the blocking element switch-back temperature is lower than the blocking element switching temperature.
• (15) Switch according to one of embodiments 1 to 14, wherein the blocking element switching temperature is equal to or higher than the switching temperature of the temperature-dependent snap part 30).
• (16) Switch according to Embodiment 14, wherein the locking element switch-back temperature is lower than the switch-back temperature of the temperature-dependent snap part 30).
• (17). Switch according to one of embodiments 1 to 16, wherein the switching mechanism 14 has a temperature-independent spring part 28 which is connected to the movable contact member 42, the temperature-dependent snap part 30 acting on the spring part 28 when the switching temperature is exceeded and thereby the movable contact member 42 from the first contact 48 takes off.
• (18) Switch according to one of embodiments 1 to 17, wherein the temperature-dependent snap part 30 is a bi- or tri-metal snap disk.
• (19) Switch according to Embodiment 17, wherein the movable contact member 42 includes a movable contact part 46 cooperating with the first contact 48, and wherein the spring part 28 cooperates with the second contact 50.
• (20) Switch according to one of embodiments 1 to 19, wherein the movable contact member 42' comprises a current transmission member 76 which cooperates with both stationary contacts 48', 50'.

Claims (13)

Temperature-dependent switch (10, which has a first and a second stationary contact (48, 50) and a temperature-dependent switching mechanism (14) with a movable contact member (42), the switching mechanism (14) counteracting the contact member (42) in its first switching position presses the first contact (48) and thereby establishes an electrically conductive connection between the two contacts (48, 50) via the contact member (42) and in its second switching position keeps the contact member (42) at a distance from the first contact (48) and thus interrupts the electrically conductive connection between the two contacts (48, 50), the temperature-dependent switching mechanism (14) having a temperature-dependent snap part (30) which snaps from its geometric low-temperature configuration into its geometric high-temperature configuration when a switching temperature is exceeded and when it subsequently falls below one Switch-back temperature snaps back from its geometric high-temperature configuration back to its geometric low-temperature configuration, with a snapping of the temperature-dependent snap part (30) from its geometric low-temperature configuration into its geometric high-temperature configuration bringing the switching mechanism (14) from its first switching position to its second switching position and thus the switch (10 ) opens, and a closing lock (52) is provided which prevents the opened switch (10) from closing again by holding the switching mechanism (14) in its second switching position as soon as it is activated, the closing lock (52) a locking element (54) which is at least partially made of a shape memory alloy and has an opening (56) through which the movable contact member (42) protrudes, and which is designed to change its shape from a first shape when a locking element switching temperature is exceeded , in which the locking element (54) does not activate the locking lock (52), to change into a second form in which the locking element (54) activates the locking lock (52) by exerting a force on a part of the switching mechanism (14). , which holds the rear derailleur (14) in its second switching position, characterized in that the locking element (54) is arranged on a second side of the temperature-dependent snap part (30) facing away from the first contact (48) and is designed to, in its second form, the force that the switching mechanism (14) has in its second Switch position holds, directly or indirectly on the contact member (42). Switch according to claim 1, characterized in that the blocking element (54) is designed essentially in the shape of a plate or disk. Switch according to claim 1 or 2, characterized in that the opening (56) is designed as a through hole. Switch according to one of claims 1 to 3, characterized in that the opening (56) is arranged centrally in the blocking element (54). Switch according to one of claims 1 to 4, characterized in that at least one slot (62) is provided in the blocking element (54), which adjoins the opening (56). Switch according to claim 5, characterized in that the at least one slot (62) runs in a straight line and extends radially outwards from the opening (56). Switch according to one of claims 1 to 4, characterized in that at least three slots (62) are provided in the blocking element (54), each of which adjoins the opening (56), extends in a straight line and extends radially from the opening (56). extend outwards. Switch according to one of claims 1 to 7, characterized in that the switch (10) has a housing (12) and that the locking element (54) is attached to the housing (12) with its edge (58). Switch according to claim 8, characterized in that the edge (58) of the blocking element (54) is made of an electrically insulating material (60) or is coated with an electrically insulating material (60). Switch according to claim 8 or 9, characterized in that the housing (12) has a lower part (16) closed by an upper part (18), and that the locking element (54) is located on a circumferential shoulder (22) arranged in the lower part (16). ) rests and is clamped between the lower part (16) and the upper part (18). Switch according to one of claims 1 to 10, characterized in that the shape memory alloy is a shape memory alloy with a one-way memory effect. Switch according to one of claims 1 to 10, that the shape memory alloy is a shape memory alloy with a two-way memory effect, and that the blocking element (54) is designed to change its shape from the second shape to the first shape when the switch-back temperature falls below a blocking element change, wherein the blocking element switch-back temperature is lower than the blocking element switching temperature and / or lower than the switch-back temperature of the temperature-dependent snap part (30). Switch according to one of claims 1 to 12, characterized in that the blocking element switching temperature is equal to or higher than the switching temperature of the temperature-dependent snap part (30).

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