EP3511968B1 - Temperature-dependent switch - Google Patents

Description

The present invention relates to a temperature-dependent switch which has a first and a second stationary mating contact, a temperature-dependent switching mechanism with a contact element and a housing on which the two mating contacts are provided and in which the switching mechanism is arranged, the switching mechanism being in its first switching position presses the contact element against the first counter-contact and thereby creates an electrically conductive connection between the two counter-contacts via the contact element and keeps the contact element at a distance from the first counter-contact in its second switching position, with a closing lock being provided which prevents a switch once opened from being closed again .

A switch, which forms the basis for the preambles of claims 1 and 2, is known from EP 0 591 755 A1 famous. Another such switch is from DE 10 2013 101 392 A1 famous.

The known switch has a temperature-dependent switching mechanism with a temperature-dependent bimetallic snap-action disc and a bistable spring disc, which carries a movable mating contact or a current transmission element. When the bimetallic snap disk is heated to a temperature above its set temperature, it lifts the mating contact or current transfer member away from the mating contact or contacts against the force of the spring washer, thereby forcing the spring washer into its second stable configuration in which the derailleur is in is in its high temperature position.

If the switch and thus the bimetallic snap-action disc cool down again, it springs back into its first configuration. Due to the design, however, its edge cannot be supported on a counter bearing, so that the spring washer remains in the configuration in which the switch is open.

The known switch thus remains in its open position after it has been opened once, even if it cools down again. However, tests in the applicant's company have shown that the known switch closes again in the event of stronger mechanical shocks, so that it may not be optimally usable in some applications from a safety point of view.

The one from the DE 10 2007 042 188 B3 known switch has three switch positions. In its low-temperature position, the switch is closed, so that the two mating contacts are electrically connected to one another.

In its high temperature position, the switch is open so no current can flow through the switch. In its cool down position, the switch remains open even though the dome has cooled back down and thus resumed its cryogenic configuration.

In this way, the temperature-dependent switch is a one-time switch which, after being opened once, also remains open when the temperature of the snap-action disk has decreased again.

Comparable one-time switches are from DE 86 25 999 U1 as well as the DE 25 44 201 A famous.

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 arranged mechanically on the device in such a way that it is thermally connected to it.

Below the response temperature of the snap-action disc, the two mating contacts are electrically connected with one another so that the circuit is closed and the load current of the device to be protected flows through the switch. If the temperature rises above a permissible value, the snap-action disc lifts the contact element from the counter-contact against the actuating force of the spring disc, as a result of which the switch opens and the load current of the device to be protected is interrupted.

The now de-energized device can then cool down again. In the process, the switch that is thermally coupled to the device cools down again, which would then actually close again automatically.

With the four switches mentioned above, it is now ensured that this switching back does not take place in the cooling position, so that the device to be protected cannot switch on again automatically after it has been switched off. This is a safety function intended to prevent damage, as is the case, for example, with electric motors that are used as drive units.

It is also known to provide temperature-dependent switches of this type 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 disk above its response temperature.

However, this 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, current no longer flows through the temperature-dependent switch, so that the self-locking function is no longer applicable.

After the electrical device is switched on again, the switch would be in the closed state again, so that the device can heat up again, which could lead to consequential damage.

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

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

With the ones mentioned above DE 10 2007 042 188 B3 For example, the spring washer is a circular snap-action spring washer to which the contact member is centrally attached. The contact member is, for example, a movable contact part which is pressed by the snap-action spring disc against the first stationary mating contact which is arranged on the inside of a cover of the housing of the known switch.

With its edge, the snap-action spring disc presses against an inner base of a lower part of the housing, which acts as a second mating contact.

In this way, the self-electrically conductive snap-action spring disk creates an electrically conductive connection between the two mating contacts.

The external connection of the known switch takes place on the one hand via the outside of the electrically conductive lower part and on the other hand via a plated-through hole of the first stationary mating contact through the upper part on its outer side, where a solder connection can be provided, for example.

In the known switches, the bistable snap-action disk is a bimetallic snap-action disk which changes over from its convex to a concave configuration when its response temperature is exceeded.

The bimetallic snap-action disc has a central passage opening with which it is slipped over the movable contact part that is attached to the spring snap-action disc.

In its low-temperature position, the bimetallic snap-action disc lies loosely on the contact part. If the temperature of the bimetallic snap-action disc increases, it jumps over to its high-temperature position, in which it presses with its edge on the inside of the upper part of the housing and with its center presses on the spring snap-action disc so that it moves from its first in flips over its second stable configuration, lifting the movable contact part from the stationary mating contact and opening the switch.

If the temperature of the switch cools down again, the bimetallic snap-action disc jumps back to its low-temperature position. In doing so, its edge comes into contact with the edge of the snap-action spring disk and its center comes into contact with the upper part of the housing. However, the actuating force of the bimetal snap-action disc is not sufficient to allow the spring-action snap-action disc to switch back to its first configuration.

Only when the switch cools down significantly does the bimetallic snap-action disc continue to curve, so that it can finally press the edge of the spring-action snap-action disc down onto the inner floor of the lower part so far that the spring-action snap-action disc snaps back into its first configuration and the switch closes again.

The one from the DE 10 2007 042 188 B3 Known switches remain open after being opened once until they have cooled down to a temperature below room temperature, for which purpose a cold spray can be used, for example.

Although this switch satisfies the relevant safety requirements in many applications, it has turned out that due to the tensioning of the bimetallic snap-action disc between the upper part of the housing and the edge In rare cases, the spring snap-in disc springs back unintentionally.

According to the above illustration, the known switch leads the load current of the device to be protected through the spring snap-action disc, which is only possible up to a certain current intensity. At higher current levels, the spring snap-action disc heats up to such an extent that this self-heating of the current leads to the switching temperature of the bimetallic snap-action disc being reached before the device to be protected has actually reached its permissible temperature.

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

In this switch, the edge of the spring snap-action disc is fixed to the lower part of the housing, while the bimetallic snap-action disc is provided between the spring snap-action disc and the inner bottom of the lower part.

Below the response temperature of the bimetal snap-action disc, the spring snap-action disc presses the contact plate against the two mating contacts. If the bimetal snap-action disc jumps into its high-temperature position, its edge presses against the spring snap-action disc and its center pulls the spring snap-action disc away from the upper part, so that the contact plate comes out of contact with the two mating contacts. So that this is geometrically possible, the contact plate, spring snap-action disc and bimetallic snap-action disc are captively connected to one another by a centrally running rivet.

When the temperature of the bimetallic snap-action disc drops again, it jumps back to its low-temperature position, but the spring washer remains in its position adopted configuration, since the bimetallic snap-action disc lacks a counter bearing for its edge, so that it cannot press the current transmission member against the two stationary counter contacts again.

Due to its design, this switch therefore has a self-locking function. In the event of strong mechanical shocks, however, in rare cases the spring snap-in disc can spring back unintentionally.

From the one already mentioned DE 25 44 201 A1 discloses a temperature-dependent switch with a current transmission element designed as a contact bridge, in which the contact bridge is pressed against two stationary counter-contacts via a closing spring.

The contact bridge is in contact with a temperature-dependent switching mechanism via an actuating bolt, which consists of a bimetallic snap-action disc and a spring washer, both of which are clamped at their edge.

As with the one from the DE 10 2007 042 188 B3 known switches, the spring washer and the bimetal snap-action disc are both bistable, the bimetal snap-action disc in a temperature-dependent manner and the spring disc in a temperature-independent manner.

If the temperature of the bimetallic snap-action disc increases, it presses the spring washer into its second configuration, in which it presses the actuating bolt against the contact bridge, lifting it off the stationary mating contacts against the force of the closing spring.

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

External pressure can now be applied to the contact bridge 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 against the force of the closing spring from the mating contacts, 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 it is closed, a spring washer with a very high level of stability is required in the second configuration.

Another three-position switch is from the one already mentioned DE 86 25 999 U1 famous. In this known switch, a cantilevered spring tongue is provided, which carries a movable contact part at its free end, which interacts with a fixed mating contact.

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

In this switch, the calotte has to 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 calotte has to apply a high actuating force in its second configuration.

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

Against this background, the present invention has the object of further developing the switch mentioned above in such a way that it has a simple design construction ensures a safe interruption of the circuit even when the switch is in the cool-down position and in the event of strong shocks.

According to claim 1, this object is achieved in that the locking device interacts directly with the contact element and has at least a first locking element on the contact element and a second locking element that interacts therewith and is arranged in the housing and connected to it, and that the locking device has the temperature-dependent The rear derailleur is permanently locked mechanically in its second switching position.

According to claim 2, the object is achieved in that the closing lock interacts directly with the contact element and has at least one locking element, which interacts with the contact element and a component arranged between the upper part and the lower part, and that the closing lock activates the temperature-dependent switching mechanism in its second switching position permanently mechanically locked.

Because, according to the invention, the closing lock permanently locks the derailleur mechanically, it cannot close again after it has been opened once, even if strong vibrations or temperature fluctuations occur. As a result of the mechanical locking of the temperature-dependent switching mechanism, the switch is also mechanically locked, which is used synonymously in the context of the present application.

The closing lock is realized by snapping between the contact member and the switch housing or by resilient tongues which change their position after opening the switch and are positioned so that they act as spacers between the contact member or the spring bearing this or snap-action disc and a component lying above the spring or snap-action disc.

The temperature-dependent switching mechanism contains a temperature-dependent snap-action element, preferably a bimetallic snap-action disc, which opens in the usual way of the rear derailleur caused by it or she lifts the contact member from the counter-contact. According to the invention, once the switch has been opened, it is then locked in the open state.

However, the temperature-dependent switching mechanism can, as is often the case, also have a bistable spring washer which, when the switch is closed, causes the closing force and thus the contact pressure between the movable contact element and the counter-contact. As a result, the bimetal snap-action disc is mechanically relieved, which has a positive effect on its service life and the long-term stability of the response temperature.

Against this background, it is preferred if the temperature-dependent switching mechanism comprises a temperature-dependent snap-action disk with a geometric high-temperature configuration and a geometric low-temperature configuration and a bistable spring disk on which the contact element is arranged, the spring disk having two temperature-independent stable geometric configurations and in its first configuration the Contact member presses against the first mating contact and, in its second configuration, keeps the contact member spaced from the first mating contact.

It is also preferred if the edge of the snap-action disc is supported on a part of the switch during the transition from its low-temperature configuration to its high-temperature configuration, thereby acting on the spring disc in such a way that it changes over from its first to its second stable configuration, with more preferably the Snap disk and the spring washer are fixed on their respective center on the contact member.

The advantage here is that largely conventional temperature-dependent switching mechanisms can be used for the new switch, so that the design effort for starting series production of the new switch is low.

It is particularly preferred if the snap-action disk is fixed to the contact element and a free space is provided for the edge of the snap-action disk, into which the edge protrudes at least partially when the snap-action disk assumes its low-temperature configuration again when the spring disk is in its second configuration.

This construction has the above-mentioned DE 10 2013 101 392 A1 known advantages. When the snap-action disk springs back into its low-temperature position, its edge enters the free space in which it has no abutment, so that it cannot push the spring disk back into its first configuration.

Even strong mechanical shocks do not result in the spring washer springing back into its first configuration in which it would close the switch again, since, according to the invention, it is prevented from doing so by the closing lock.

Without this free space, that is, with a structure of the switch such as that mentioned in the introduction DE 10 2013 101 392 A1 serves as the starting point of the invention there, the bimetallic snap-action disc would exert pressure on the spring washer when it springs back into its low-temperature configuration, which would allow it to snap back into its other stable geometric configuration. According to the invention, however, this process is prevented by the closing lock.

If, in a further development, the free space for the edge of the bimetallic snap-action disk is provided in addition to the mechanical locking by the closing lock, there is initially no closing pressure that the closing lock has to absorb. Like in the DE 10 2013 101 392 A1 explained, the switch remains permanently open.

However, if severe mechanical shock causes the bimetal dome to snap back to its cryogenic configuration, the mechanical detent provided by the present invention will still hold the switch open.

In this development, the closing lock only has to absorb the closing pressure in rare cases, which further increases the reliability of the new switch.

It is particularly preferred if the contact element comprises a movable contact part that interacts with the first mating contact, and the spring washer interacts with the second mating contact, with the spring washer preferably being electrically connected to the second mating contact via its edge, at least in its first configuration.

This configuration is in principle already from the DE 10 2007 042 188 B3 or the DE 10 2013 101 392 A1 famous. It causes the snap disk to be in any position of the switch is current-loaded, but that the load current of the electrical device to be protected flows through the spring washer.

In another exemplary embodiment, the contact element comprises a current transmission element that interacts with the two counter-contacts.

The advantage here is that the new switch can carry significantly higher currents than the one from the DE 10 2007 042 188 B3 known switches. When the switch is closed, the contact element ensures the electrical short circuit between the two mating contacts, so that the load current no longer flows through not only the snap-action disk but also the spring disk, as is already the case in principle from the DE 10 2013 101 392 A1 is known.

It is particularly preferred if the switch comprises a housing on which the two mating contacts are provided and in which the switching mechanism is arranged.

This measure is known per se, it ensures that the rear derailleur is protected against the ingress of dirt. The case can be an individual case of the switch or a pocket on the device to be protected from overheating.

If the edge of the spring washer is fixed to the housing and the contact element is a movable contact part, the edge of the spring washer is always firmly connected to the housing, so that good electrical contact resistance is ensured there. This means that the new switch can carry larger currents than the one from the DE 10 2007 042 188 B3 known switch, where also the contact resistance to the base is determined by the contact pressure of the spring washer itself.

If a current transmission element is used as the contact element, the fixing of the spring washer with its edge on the housing ensures that the contact element remains securely positioned relative to the mating contacts.

It is also preferred if the housing has a lower part closed by an upper part, with the first mating contact or each of the two mating contacts being arranged on an inside of the upper part.

This measure is structurally known per se; in the new switch, it ensures that when the upper part is mounted on the lower part, the geometrically correct association between the mating contact or mating contacts and the respective contact element is also produced at the same time.

Furthermore, it is preferred if the lower part has an inner base, over the edge area of which the free space is provided.

This measure is particularly advantageous in terms of design, since it makes it possible in the simplest way to provide a known temperature-dependent switch with the three switch positions mentioned at the outset if a bistable spring part with two temperature-independently stable configurations is used there in each case.

This measure would, for example, in the case of the DE 196 23 570 A1 known switches with a moving contact part do not in themselves lead to the switch remaining open in the cooling position, because that is where the edge of the bimetallic snap-action disc is supported on the outer edge of the base and the spring part would thus be pressed back into its high-temperature position.

The same situation arises with the from the DE 10 2011 016 142 A1 known switch, in which a spring washer firmly clamped at its edge and underneath a snap-action disc are arranged below a current transmission member, which is also supported with its edge on the inside on the bottom of the lower part, so that when it cools down it would press a bistable spring part back into its first configuration .

In order to avoid this, without the additional free space now provided, the actuating force of the spring washer would have to be so high in its second configuration to be interpreted so that it cannot be pushed back into its first configuration by the dome.

In other words, in particular because the snap-action disc is arranged between the spring washer and the base of the lower part, but there is free space at the edge of the base for the edge of the snap-action disc in its cooling position, the new switch is not only easy to manufacture, it also remains securely open in its cool down position.

The bottom part can be made of electrically conductive material and preferably the top part can be made of electrically insulating material, with the bistable snap-action disk being able to be a bimetal or trimetal snap-action disk.

It is particularly preferred if the closing lock interacts directly with the contact element.

The advantage here is that the closing lock acts in the center of the snap-action washer and possibly the spring washer, ie where the closing force is exerted that the closing lock has to absorb. Another advantage is that known temperature-dependent switching mechanisms can be used in the new switch. Only the contact element has to be modified.

According to the solution defined in claim 1, it is provided that the closing lock has at least a first latching element on the contact element and a second latching element cooperating therewith, which is arranged in the housing and connected to it.

This measure is structurally advantageous because, in addition to the minor structural change to the contact element, only at least one latching element also needs to be provided in the housing.

The first latching element can be arranged in the area of an outer surface of the contact element and/or an inner surface in a bottom opening of the contact element preferably the first or second latching member can be designed as a circumferential groove, a circumferential bead, a resilient tongue, recess or latching lug, wherein the first latching member can also have circumferentially distributed latching lugs and/or resilient tongues.

The first and/or second latching element can be designed to be radially flexible.

This measure is also structurally advantageous because one or both latching members can be resilient and/or made of elastic material, which enables the two latching members to engage with one another when the switch or switching mechanism is first opened without having to overcome major forces .

According to the solution defined in claim 2, it is provided that the closing lock has at least one locking member which interacts with the contact member and a component arranged between the upper part and the lower part.

While the above-mentioned latching elements are arranged, so to speak, below the snap and possibly spring washer, the locking elements are arranged above the snap and possibly spring washer and serve as a kind of spacer that prevents the contact element from coming into contact again after the switch has been opened reaches the first mating contact, the blocking member preferably being connected to the contact member or to a spring washer or snap-action washer carrying the contact member.

This measure is also advantageous in terms of design, with the blocking elements acting like spacers also ensuring that the switch is reliably kept open.

It is preferred if the component comprises a disc with a through-opening for the contact element, and the blocking element has at least one radially outwardly resilient tongue which sits under tension in the through-opening when the temperature-dependent switching mechanism is in its first switching position, and which is supported on an underside of the disc when the temperature-dependent switching mechanism is in its second switching position.

The advantage here is that conventional temperature-dependent switching mechanisms can be used, on whose contact element and/or whose spring washer or snap-action disk the blocking element or elements can also be subsequently mounted. The insulating film that is present between the upper part and the lower part of the housing anyway serves as a disc, which serves as a seal and/or for electrical insulation.

On the other hand, it is preferred if the component is designed as a spacer ring and the blocking member has at least one radially outwardly resilient tongue which is arranged on the contact member designed as a current transmission member, the tongue resting under tension on an inner surface of the spacer ring when the temperature-dependent switching mechanism is in its first switching position, and is supported on the spacer ring when the temperature-dependent switching mechanism is in its second switching position, or when the component is designed as a spacer ring, and the locking member has at least one radially inwardly resilient tongue which is attached to a Inner surface of the spacer ring is arranged and is applied under tension to the contact member designed as a power transmission member when the temperature-dependent switching mechanism is in its first switching position, and is supported on the power transmission member when the temperature-dependent switching mechanism is in its second switching position.

Such spacer rings are often inserted between the lower part and the upper part in temperature-dependent switches in order to achieve the required overall height, which allows a sufficiently large switching path between counter-contact and contact element in order to ensure the necessary electrical insulation in the open switch.

The blocking element can have several resilient tongues arranged to form a ring, which is arranged like a kind of crown or spring broom on the contact element, the snap-action or spring washer or the spacer ring, and can also be provided subsequently without major structural changes in existing switch constructions.

Further advantages result from the description and the attached drawing.

It goes without saying that the features mentioned above and those still to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

Fig. 1

in einer schematischen Seitendarstellung ein erstes Ausführungsbeispiel des neuen Schalters in seiner Tieftemperaturstellung;

Fig. 2

eine Darstellung wie Fig. 1, jedoch in Hochtemperaturstellung des neuen Schalters;

Fig. 3

in einer schematischen Seitendarstellung ein zweites Ausführungsbeispiel des neuen Schalters in seiner Tieftemperaturstellung;

Fig. 4

eine Darstellung wie in Fig. 3, jedoch in Hochtemperaturstellung des neuen Schalters;

Fig. 5

in einer Darstellung wie Fig. 3 und 4 den neuen Schalter in seiner Abkühlstellung;

Fig. 6

ein erstes Ausführungsbeispiel für eine bei den Schaltern aus Fig. 1 bis 5 einsetzbare Schließsperre;

Fig. 7

ein zweites Ausführungsbeispiel für eine bei den Schaltern aus Fig. 1 bis 5 einsetzbare Schließsperre;

Fig. 8

ein drittes Ausführungsbeispiel für eine bei den Schaltern aus Fig. 1 bis 5 einsetzbare Schließsperre;

Fig. 9

ein viertes Ausführungsbeispiel für eine bei den Schaltern aus Fig. 1 bis 5 einsetzbare Schließsperre;

Fig. 10

ein fünftes Ausführungsbeispiel für eine bei den Schaltern aus Fig. 1 bis 5 einsetzbare Schließsperre;

Fig. 11

ein sechstes Ausführungsbeispiel für eine bei den Schaltern aus Fig. 1 bis 5 einsetzbare Schließsperre; und

Fig. 12

ein siebtes Ausführungsbeispiel für eine bei dem Schalter aus Fig. 3 bis 5 einsetzbare Schließsperre.

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

1

in a schematic side view a first exemplary embodiment of the new switch in its low-temperature position;

2

a representation like 1 , but with the new switch in the high-temperature position;

3

in a schematic side view, a second embodiment of the new switch in its low-temperature position;

4

a representation as in 3 , but with the new switch in the high-temperature position;

figure 5

in a representation like 3 and 4 the new switch in its cool down position;

6

a first exemplary embodiment for one of the switches Figures 1 to 5 insertable locking device;

7

a second embodiment for one of the switches Figures 1 to 5 insertable locking device;

8

a third exemplary embodiment for one of the switches Figures 1 to 5 insertable locking device;

9

a fourth exemplary embodiment for one of the switches Figures 1 to 5 insertable locking device;

10

a fifth exemplary embodiment for one of the switches Figures 1 to 5 insertable locking device;

11

a sixth exemplary embodiment for one of the switches Figures 1 to 5 insertable locking device; and

12

a seventh embodiment for a at the switch from Figures 3 to 5 usable locking device.

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

The switch 10 has a housing 11 in which a temperature-dependent switching mechanism 12 is provided.

The housing 11 comprises a pot-like lower part 14 made of electrically conductive material and a flat, insulating upper part 15 which is held on the lower part 14 by a bent edge 16 . For the sake of clarity, the folded edge 16 is not shown as a solid line across the upper part 15 .

A spacer ring 17 is provided between the upper part 15 and the lower part 14 and keeps the upper part 15 at a distance from the lower part 14 .

The upper part 15 has an inner side 18 on which a first stationary mating contact 19 and a second stationary mating contact 21 are provided. The mating contacts 19 and 21 are designed as rivets which extend through the upper part 15 and end in heads 22 and 23 on the outside, which are used for the external connection of the switch.

The rear derailleur 12 comprises a current transmission element 24 as a contact element, which in the exemplary embodiment shown is a contact plate whose upper side 25 has an electrically conductive coating, so that when it is in FIG 1 shown plant on the counter-contacts 19 and 21 for an electrically conductive connection between the two counter-contacts 19 and 21 provides.

The current transmission element 24 is connected to a bistable spring washer 27 and a bistable snap-action disk 28 via a rivet 26, which is also to be regarded as part of the contact element.

The spring washer 27 has two temperature-independent configurations, the first of which is shown in 1 and the second configuration in 2 is shown.

The snap disk 28 has two temperature dependent configurations, namely its cryogenic configuration, shown in 1 is shown, as well as its high-temperature configuration, which is shown in 2 is shown.

Inside the lower part 14 there is a peripheral shoulder 29 on which the spacer ring 17 rests. The spring washer 27 is clamped with its edge 31 between the shoulder 29 and the spacer ring 17 , while its center 32 rests on a shoulder 33 on the rivet 26 . The spring washer 27 is thus clamped at its center 32 between the current transmission member 24 and the shoulder 33 .

In 1 Further down and radially further outwards, another shoulder 34 can be seen on the rivet 26, on which the snap disk 28 rests with its center 35.

The center 35 rests freely on the shoulder 34.

With its edge 36, the snap-action disk 28 lies freely above an inner base 37 of the lower part 14.

According to 1 the inside 37 is designed as a wedge-shaped, radially outwardly rising support shoulder 38, which, as in the case of the DE 10 2011 016 142 A1 known switch as a support surface for the edge 36 is used.

The rivet 36 also has a base 42 which points towards the inner base 37, but in relation to this in the low-temperature position of the switch 10 according to FIG 1 has a spacing indicated at 43.

If the temperature of snap disk 28 now increases, its rim 36 will rise 1 upwards, so that the snap-action disc 26 moves from its in 1 convex position shown in their in 2 concave position shown, in which its edge 36 bears against a part of the switch 10, in this case against the spring washer 27, as shown in FIG 2 can be seen.

On transition from their low-temperature configuration, the 1 to their high temperature configuration 2 the snap-action disc 28 is thus supported with its edge 37 on the spring washer 27, with its center 35 pressing on the shoulder 34 of the rivet 26 and thereby pushing the current transmission member 24 away from the stationary mating contacts 19 and 21 against the force of the spring washer 27.

As a result of this movement, the bottom 42 of the rivet 26 is deposited on the inner bottom 37 of the lower part 14, with the spring washer 27 simultaneously being released from its in 1 shown first configuration snaps into its also stable second geometric configuration, which is shown in 2 is shown.

According to the spring washer 27 in its first configuration 1 keeps the power transmission member 24 in contact with the mating contacts 19 and 21, keeps them in accordance with their second configuration 2 the current transmission member 24 at a distance from the mating contacts 19 and 21, so that the switch 10 is open.

While the switch is 10 in 1 is in its cryogenic closed position, it is in 2 in its high temperature open position.

If the temperature of the device to be protected and thus the temperature of the switch 10 cools down again, the snap disk 28 snaps back from its high-temperature configuration 2 return to their cryogenic configuration that they were already in 1 had taken.

The snap disk 28 is again in its cryogenic configuration, to which it has cooled as a result of the cooling of the device to be protected. The edge 36 of the snap disk 28 has 3 moved down, he is now on the support shoulder 38 on.

The snap disk 28, in transitioning to its cryogenic configuration, will urge the spring washer 27 back to its first configuration, as in the switch of FIG DE 10 2011 016 142 A1 the case is.

According to the invention, however, a closing lock 39 is provided, which is in the area of the in 2 indicated circles I, II, III, IV and V is arranged. For reasons of clarity are in the Figures 6 to 12 various embodiments of the closing lock 39 are shown.

while in the 1 and 2 a first exemplary embodiment of the new switch 10 is shown, in which a current transmission element 24 with rivet 26 is used as the contact element, show the Figures 3 to 5 a second exemplary embodiment of the new switch, in which a movable contact part 45, which is part of the switching mechanism 12', is used as the contact element.

The switch 10' off 3 again has a pot-like lower part 14', on whose peripheral shoulder 29 a spacer ring 17 again rests, which carries the upper part 15' with an insulating film 46 interposed.

Lower part 14' and upper part 15' are each made of electrically conductive material here, so that their outer surfaces make contact with an electrical device that is to be protected can be made. The outer surfaces are also used for the external electrical connection.

The upper part 15′ is again held on the lower part 14′ by the bent edge 16 thereof, a further insulation layer 47 being attached to the upper part 15′ on the outside.

Here, too, the switching mechanism 12 ′ includes the spring washer 27 and the snap-action washer 28 , the spring washer 27 being clamped with its edge 31 between the shoulder 29 and the spacer ring 17 .

With its center 32, the spring washer 27 is fixed to the contact part 45, for which purpose a ring 49 is pressed onto it.

The ring 49 has a peripheral shoulder 51 on which the snap disk 28 rests with its center 35 .

In this way, the temperature dependent circuit 12' is off 3 just as a captive unit of contact member, spring washer 27 and snap disk 28 as the derailleur 12 from 1 and 2 .

When assembling the switches 10 and 10', the switching mechanism 12, 12' can thus be inserted directly into the lower part 14, 14' as a unit.

The movable contact part 45 cooperates with a fixed mating contact 19', which is arranged on the inside of the upper part 15.

The outside of the lower part 14', which is made of electrically conductive material, serves as the second mating contact 21'.

in the in 3 As shown, the switch 12' is in its low temperature position in which the spring washer 27 is in its first configuration and the snap disk 28 is in its low temperature configuration.

The spring washer 27 presses the movable contact part 45 against the stationary counter-contact 19'.

The movable contact part 45 has a base 52 which points towards the inner base 37 of the lower part 14 ′ and is at a distance from it which is comparable to the distance 43 1 is.

Below the edge 36 of the snap disk 28 there is a circumferential free space 40 which is provided in an edge region 41 of the inner base 37 .

The switch 10' described so far has roughly the same geometric features as an exemplary embodiment of a switch from the aforementioned DE 10 2013 101 392 A1 .

In this known switch, however, there is a wedge-shaped, peripheral support shoulder 38 in the edge region 41, which has the same function as the peripheral shoulder 29 in the switch from the present disclosure 1 and 2 . This shoulder 38 is not provided in the new switch 10'.

Because the spring washer 27 is clamped with its edge 31 between the spacer ring 17 and the shoulder 29, it is electrically conductively connected there to the lower part 14' with a very low contact resistance.

At its center 32, the spring washer 27 is clamped between the movable contact part 45 and the ring 49, so that there is also a very low electrical contact resistance there.

In the closed low-temperature position of the switch 10 'according to 3 an electrically conductive connection is thus produced between the counter-contact 19' and the counter-contact 22' via the movable contact part 45 and the spring washer 27.

The snap-action disk 28 rests freely below the spring washer 27 on the support shoulder 38 .

If the temperature of the device to be protected and thus the temperature of the snap-action disc 28 increases, it snaps from the in 3 convex low-temperature configuration shown to their concave high-temperature configuration, which is shown in 4 is shown.

During this snapping, the snap-action disc 28 is supported with its edge 26 on a part of the switch 10', in this case on the edge 31 of the spring washer 27.

With its center 35, the snap-action disc 28 presses on the shoulder 51 and thus lifts the movable contact part 45 from the stationary contact part 19'.

As a result, at the same time it bends the spring washer 27 downwards at its center 32, so that the spring washer 27 moves from its first stable geometric configuration 3 into their second geometrically stable configuration 4 snapped.

In this second configuration, the spring washer 27 presses the bottom 52 of the contact part 45 against the inner bottom 37 of the base 14'.

In 4 ie the high-temperature position of the switch 10' is shown, in which it is open.

If the device to be protected and thus the snap-action disc 28 now cool down again, the snap-action disc 28 snaps back into its low-temperature position, as shown, for example, in 3 is shown. To do this, the edge moves 36 in 4 down and thus into the space 40 inside.

The switch 10' is now in its cooling position, which is figure 5 is shown.

The spring washer 27 is still in its geometrically stable second configuration, in which it keeps the contact part 45 at a distance from the counter-contact 19 ′, the contact part 45 resting with its base 52 on the inner base 37 of the lower part 14 .

The snap disk 28 is again in its low-temperature configuration, having moved into the free space 40 with its edge 36 . The snap-action disc 28 is therefore not able to move the contact part 45 or the spring washer 27 at its center 32 in figure 5 to push up.

Even with the switch 10 'from the Figures 3 to 5 locking devices 39 are again provided, which are in the area of the in figure 5 indicated circles VI, VII, VIII, IX and X are arranged. For the sake of clarity, various exemplary embodiments of the closing locks 39 used here are also shown in FIGS Figures 6 to 11 shown schematically.

The task of the closing locks 39 is to permanently mechanically lock the temperature-dependent switching mechanism 12, 12' in the high-temperature position in a switch 10, 10' once it has been opened so that it cannot close again even when the snap-action disc 28 cools down.

While at the switch 10 of 1 and 2 the closing locks 39 must permanently absorb the closing pressure exerted by the cooled snap-action disc 28, this closing pressure is missing in the switch 10' of FIG Figures 3 to 5 , because the edge 36 of the snap disk 28 does not have a bearing shoulder 38 but comes to rest in the free space 40 .

6 shows a schematic side view of a contact member 55 having an outer surface 54 , which forms the movable contact part 45 figure 5 , the rivet 26 off 2 or the power transmission member 24 off 2 to symbolize. Parallel to the outer surface 54, a component 56 of the switch 10 or 10' is indicated, which in Figure 6a a rest carrier symbolized, which is arranged on the floor 37, and in Figure 6b the spacer ring 17 of the switch 10. The component 56 is thus arranged in the switch 10, 10' and connected to it.

Between the component 56 and the contact member 55, the closing lock 39 is formed, which interacts directly with the contact member 55 here. The closing lock 39 comprises a first latching element which is arranged on the outer surface 54 and a second latching element which is attached to the component 56, more precisely the outer surface 59 thereof.

In 6 the latching members are designed as latching lugs 57, 58 which slide past one another when the switch is opened, for which purpose they are designed to be resilient or elastically yielding. In Figure 6a is the switch 10, 10 'in the closed state according to 1 or 3 , and in Figure 6b in the open state according to 2 , 4 or 5 .

In Figure 6b the latching lugs 57, 58 are latched together in such a way that the contact member 55 can no longer be moved upwards (ie to close the switch 10, 10') because it is permanently mechanically locked to the component 56.

The depictions in the 7 and 8th correspond to the one from the 6 , except that the locking members are designed as a circumferential groove 61 or circumferential bead 62. In 7 is the groove 61 on the contact member 55 and in 8 arranged on the component 56.

The bead 61 consists of elastic material and is therefore radially flexible. When the switch 10, 10' is opened, it slides along the outer surface 54 or 59 until it engages in the groove 62 and mechanically locks the contact element 55 permanently on the component 56.

Also the representations in the Figures 9 and 10 correspond to the one from the 6 , only that the locking members are designed here as a locking member in the form of a resilient tongue 68 or recess 69. In 9 is the recess 69 on the contact member 55 and in 10 arranged on the component 56.

The resilient tongue 68 is radially flexible. It lies under tension on the outer surface 54 or 59 and slides along the outer surface 54 or 59 when the switch 10, 10' is opened until it engages in the recess 69 and mechanically locks the contact element 55 permanently on the component 56.

The closing locks 39 from the Figures 6 to 10 can be formed in circles I to IV, VI and VII.

11 shows a schematic side view of a preferably central bottom opening 64 having contact member 55, which the movable contact part 45 from 3 or the rivet 26 1 to symbolize. The bottom opening 64 has an inner surface 65 and is seated on a spigot 66 which is fixed to the inner bottom 37 of the switch 10, 10' and has an outer surface 67. As shown in FIG.

On the inner surface 65 and the outer surface 67, the locking members 57, 58; 61, 62 from the Figures 6 to 10 be arranged to mechanically lock the contact member 55 to the floor 37 when the switch 10, 10' has first moved to its high temperature position in which the contact member rests on the floor 37.

The closing lock 39 from the 11 may be formed in circles V and VIII.

12 shows a detail of the switch 10' in a schematic side view Figures 3 to 5 in the area of the movable contact part 45, where 12a the low temperature position and Figure 12b corresponds to the high temperature position.

The insulating film 46 can be seen above the contact part 45, in which a through-opening 71 is provided, through which the contact part 45 comes into contact with the counter-contact 19. Distributed around the contact part 45 are a plurality of locking members 72 which are in the form of spring tongues and are arranged in the manner of a crown or a spring broom.

The spring tongues extend obliquely upwards from a ring 73, via which they are attached to the contact part 45 and/or to the spring washer 27. In the low temperature position 12a the spring tongues run through the through-opening 71 and have no mechanical function.

When the switch 10' opens, the contact member 45 moves down to the high temperature position Figure 12b . The springs come out of the through opening 71 and move radially outwards under the underside 74 of the insulating film 46.

If the switch 10' cools again and the spring washer 27 were to snap back to its low temperature configuration due to a strong shock, the switch would still not be able to close again because the locking members 72 act as spacers and prevent upward movement of the contact part 45.

In this way, too, the switch 10' is permanently locked mechanically in its high-temperature position.

The closing lock 39 from the 12 may be formed in circles IX and X.

Claims (21)

1. Temperature-dependent switch which

   comprises a first and a second stationary counter contact (19, 21; 19, 21'), a temperature-dependent switching mechanism (12; 12') with a contact member (24; 26; 45), and a housing (11, 11') on which the two counter contacts (19, 21; 19', 21') are provided, and in which the switching mechanism (12; 12') is arranged,

   wherein the switching mechanism (12; 12'), in its first switching positions, presses the contact member (24; 26; 45) against the first counter contact (19, 19') and, in this case, produces an electrically conducting connection between the two counter contacts (19, 21; 19', 21') via the contact member (24; 26; 45), and in its second switching position, holds the contact member (24; 26; 45) at a spacing from the first counter contact (19; 19'), wherein a closing lock (39), which interacts directly with the contact member (24; 26; 45) and prevents a switch that has been opened once from closing again, is provided,

   characterized in that the closing lock (39) comprises at least one first latching member (57, 58; 61, 62; 68, 69) at the contact member (24; 26; 45) and a second latching member (57, 58; 61, 62; 68, 69) interacting therewith, which second latching member is arranged in and connected to said housing (11, 11'), and that the closing lock (39) locks the temperature-dependent switching mechanism (12; 12') permanently in the second switching position thereof in a mechanical manner.
2. Temperature-dependent switch which

   comprises a first and a second stationary counter contact (19, 21; 19, 21'), a temperature-dependent switching mechanism (12; 12') with a contact member (24; 26; 45), and a housing (11, 11') on which the two counter contacts (19, 21; 19', 21') are provided, and in which the switching mechanism (12; 12') is arranged, wherein the housing (11; 11') comprises a lower part (14; 14') which is closed by an upper part (15; 15'), wherein the first counter contact (19; 19') or either of the two counter contacts (19, 21) is arranged on an inner surface (18; 18') of the upper part (15; 15'),

   wherein the switching mechanism (12; 12'), in its first switching positions, presses the contact member (24; 26; 45) against the first counter contact (19, 19') and, in this case, produces an electrically conducting connection between the two counter contacts (19, 21; 19', 21') via the contact member (24; 26; 45), and in its second switching position, holds the contact member (24; 26; 45) at a spacing from the first counter contact (19; 19'), wherein a closing lock (39), which interacts directly with the contact member (24; 26; 45) and prevents a switch that has been opened once from closing again, is provided,

   characterized in that the closing lock (39) comprises at least one locking member (72) which interacts with the contact member (45) and with a component (17; 46) which is arranged between the upper part (15; 15') and the lower part (14;14'), and that the closing lock (39) locks the temperature-dependent switching mechanism (12; 12') permanently in the second switching position thereof in a mechanical manner.
3. Switch according to Claim 1 or 2, characterized in that the temperature-dependent switching mechanism (12; 12') comprises a temperature-dependent snap disc (28) with a geometric high-temperature configuration and a geometric low-temperature configuration as well as a bistable spring disc (27) at which the contact member (24; 26; 45) is arranged, wherein the spring disc (27) comprises two geometric configurations which are stable in a temperature-independent manner and in its first configuration presses the contact member (24; 26; 45) against the first counter contact (19, 19') and in its second configuration holds the contact member (24; 26; 45) at a spacing from the first counter contact (19; 19').
4. Switch according to Claim 3, characterized in that the snap disc (28), when transitioning from its low-temperature configuration into its high-temperature configuration, is supported by its edge (36) at a part of the switch (10; 10') and, in this case, acts on the spring disc (27) such that it snaps from its first into its second stable configuration.
5. Switch according to Claim 4, characterized in that the snap disc (28) is fixed on the contact member (24; 26; 45), and in that a space (40) is provided for the edge (36) of the snap disc (28), into which space the edge (36) projects at least in part when the snap disc (28) re-assumes its low-temperature configuration with the spring disc (27) being in its second configuration.
6. Switch according to anyone of Claims 3 to 5, characterized in that the snap disc (28) and the spring disc (27) are fixed to the contact member (24; 26; 45) via their respective centers (35, 32).
7. Switch according to anyone of Claims 1 to 6, characterized in that the contact member (24; 26; 45) includes a movable contact part (45) which interacts with the first counter contact (19'), and in that the spring disc (28) interacts with the second counter contact (21').
8. Switch according to Claim 7, characterized in that the spring disc (27) communicates electrically with the second counter contact (21') via its edge (31) at least in its first configuration.
9. Switch according to anyone of Claims 1 to 6, characterized in that the contact member (24; 26; 45) includes a current transfer member (24) which interacts with both counter contacts (19, 21).
10. Switch according to Claim 1, characterized in that the housing (11; 11') comprises a lower part (14; 14') which is closed by an upper part (15; 15') , wherein the first counter contact (19; 19') or either of the two counter contacts (19, 21) is arranged on an inner surface (18; 18') of the upper part (15; 15').
11. Switch according to Claim 2 or 10, characterized in that the lower part (14; 14') comprises an inner bottom (37) and the space (40) is provided above an edge region (41) of said inner bottom.
12. Switch according to anyone of Claims 3 to 6, characterized in that the bistable snap disc (28) is a bi-metal or tri-metal snap disc.
13. Switch according to Claim 1, characterized in that the first latching member (57, 58; 61, 62; 68, 69) is arranged in the region of an outer surface (54) of the contact member (24; 26; 45).
14. Switch according to Claim 1 or 13, characterized in that the first latching member (57, 58; 61, 62; 68, 69) is arranged in the region of an inner surface (65) in a bottom opening (64) of the contact member (24; 45).
15. Switch according to anyone of Claims 1, 13 or 14, characterized in that the first or second latching member (57, 58; 61, 62; 68, 69) is realized as a circumferential groove (61), circumferential bead (62), resilient tongue (68), recess (69) or latching lug (57, 58).
16. Switch according to anyone of Claims 1, 13, 14 or 15, characterized in that the first and/or second latching member (57, 58; 61; 68) is realized so as to be radially yielding.
17. Switch according to Claim 2, characterized in that the component (46) includes a disc with a through-opening (71) for the contact member (45), and the locking member (72) comprises at least one radially outwardly resilient tongue, which sits in the through-opening (71) under tension when the temperature-dependent switching mechanism is situated in its first switching position and which is supported on an underside (74) of the disc when the temperature-dependent switching mechanism is situated in its second switching position.
18. Switch according to Claim 2 or 17, characterized in that the locking member (72) is connected to the contact member (45).
19. Switch according to Claim 2 or 17, characterized in that the locking member (72) is connected to a spring disc (27) or snap disc (28) which carries the contact member (45).
20. Switch according to Claim 2, characterized in that the component is realized as a spacer ring (17), and the locking member (72) comprises at least one radially outwardly resilient tongue (68) which is arranged on the contact member (24; 26; 45) which is realized as a current transfer member (24), wherein the tongue (68) abuts against an inner surface of the spacer ring (24) under tension when the temperature-dependent switching mechanism is situated in its first switching position, and is supported on the spacer ring (17) when the temperature-dependent switching mechanism is situated in its second switching position.
21. Switch according to Claim 2, characterized in that the component is realized as a spacer ring (17), and the locking member (72) comprises at least one radially inwardly resilient tongue (68) which is arranged on an inner surface of the spacer ring (17) and abuts against the contact member (24; 26; 45), which is realized as a current transfer member (24), under tension when the temperature-dependent switching mechanism is situated in its first switching position, and is supported on the current transfer member (24) when the temperature-dependent switching mechanism is situated in its second switching position.

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