EP3796357B1 - Temperature-dependent switch - Google Patents

Description

The present invention relates to a temperature-dependent switch with a housing that has an upper part and a lower part closed by the upper part, with a first and a second stationary contact being arranged on the housing, of which at least the first stationary contact is arranged on the upper part, and wherein a temperature-dependent switching mechanism with a movable contact element is arranged in the housing. In its first switching position, the switching mechanism presses the movable contact element against the first contact and thereby creates an electrically conductive connection between the two contacts via the contact element. In its second switching position, the switching mechanism keeps the movable contact member at a distance from the first contact. In the switch according to the invention, a closing lock is also provided, which prevents a switch that has been opened from being closed again by permanently locking the switching mechanism mechanically in its second switching position.

A generic switch is already from the DE 10 2018 100 890 B3 and the DE 24 32 901 A1 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.

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. 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 rises above a permissible value, the switching mechanism lifts the movable contact element from the mating contact, as a result of which the switch opens and the load current of the device to be protected is interrupted. The now unpowered The 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.

At the one from the DE 10 2018 100 890 B3 known switches, however, a closing lock ensures 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. The locking mechanism locks the rear derailleur mechanically so that once opened, the rear derailleur cannot close again, even if there are strong vibrations or temperature fluctuations.

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

Because of their switching behavior, switches of this type, which do not close again after being opened once, are also referred to as one-time switches.

Another switch of this type is from the DE 10 2013 101 392 A1 famous. This switch has a temperature-dependent switching mechanism with a temperature-dependent bimetallic snap-action disc and a bistable spring disc, which carries a movable contact or a current transmission element. When the bimetallic snap disk is heated to a temperature above its set temperature, it lifts the 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 low-temperature position. Due to the design, however, 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 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 DE 10 2013 101 392 A1 well-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.

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 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, 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 therefore 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 switches avoided, in which the self-holding function is not implemented electrically, but by a bistable spring part, which 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 caused by the snap-action spring disk is pressed against the first stationary contact arranged inside on a cover of the housing of the known switch. With its edge, the snap-action spring disc is pressed against an inner base of a lower part of the housing, which acts as a second contact. In this way, the self-electrically conductive snap-action spring disk creates an electrically conductive connection between the two mating contacts.

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 into 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 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 been found that due to the strain of the bimetallic snap-action disc between the upper part of the housing and the edge of the spring snap-action disc, in rare cases the spring snap-action disc springs back unintentionally.

From the DE 10 2013 101 392 A1 it is also known to use a current transmission element as the movable contact element, for example in the form of a contact plate, which is carried by the snap-action spring disk. Both stationary contacts are now arranged on the inside of the cover of the housing, with an electrically conductive connection being produced between these two 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 stationary contacts. If the bimetallic 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 bimetal snap-action disc drops again, it springs back to its low-temperature position, but the spring disc remains in its assumed configuration because the bimetal snap-action disc lacks a counter bearing for its edge, so that it does not return the current transmission member against the two stationary contacts can press.

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

From the DE 25 44 201 A1 Furthermore, a temperature-dependent switch with a current transmission element designed as a contact bridge is known, 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 are also in this switch, the spring washer and the bimetal snap-action disc both bistable, the bimetal snap-action disc in a temperature-dependent manner and the spring washer 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 switch with three positions is from the 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.

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

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

Against this background, the object of the present invention is to further develop the switch mentioned at the outset in such a way that it can be manufactured more simply and thus more cost-effectively and yet reliable interruption of the circuit is ensured even when the switch is in the cool-down position and in the event of strong vibrations.

According to the invention, this object is achieved in that the closing lock has an essentially disc-shaped or plate-shaped locking element, which is arranged locally between the rear derailleur and an inner floor surface of the lower part, is arranged clamped in the lower part or is connected to it with a material fit and has a first latching element, which cooperates with a arranged on the movable contact member second locking member in the second switching position to lock the switching mechanism.

Because the closing lock the rear derailleur similar to that of the DE 10 2018 100 890 B3 Known switches mechanically locked permanently, it can not close again after opening 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 within the scope of the present invention. The switch according to the invention is thus permanently prevented from downshifting.

The closing lock is implemented by latching the first latching element arranged on the locking element with the second latching element arranged on the movable contact element. The first and the second latching member thus act as opposing components that guarantee latching of the rear derailleur after it has been opened. For this purpose, both the first and the second latching element can each have one latching element, two latching elements or a plurality of latching elements.

Unlike the one from the DE 10 2018 100 890 B3 known closing lock, the locking element belonging to the closing lock according to the invention is designed as a separate component which can be mounted relatively easily in the lower part of the switch. The The lower part as well as the other components of the switch can thus be manufactured relatively easily and inexpensively, independently of the closing lock. The locking element can also be used in a very simple and inexpensive manner in the lower part of the switch. It is either bonded to the lower part or clamped in it. The manufacture of the closing lock is thus as simple and inexpensive as possible.

The locking element is preferably an essentially plate-shaped or disc-shaped body. The locking element is preferably at least largely in the form of a cylinder whose radius is many times greater than its thickness. “Essentially plate-shaped or disk-shaped” is understood here to mean that the locking element does not necessarily have to be exactly plate-shaped or disk-shaped, since individual elements or sections of the locking element are simply plates. or disc shape may vary. Overall, however, it is mostly plate- or disk-shaped, i.e. it is always wider than it is high or thick

However, the first locking element (or the locking elements) arranged on the locking element can deviate from the pure plate or disc shape. Likewise, it is not absolutely necessary for the locking element to be a continuous plate or Sa ² +b ² =c ² disk made of solid material, since one or more recesses or recesses or holes can be provided in it.

According to the invention, the locking element is arranged locally between the rear derailleur and the inner bottom surface of the lower part. So it is below the rear derailleur.

The two locking members (first and second locking member) act as a kind of anchor with a corresponding counter-holder. They keep the switching mechanism in the open state after its temperature-dependent opening and prevent a corresponding downshift even after the switch has cooled down below the switching mechanism's reset temperature.

The object on which the invention is based is thus completely solved.

According to one embodiment, it is provided that the first latching element or the second latching element has a spring tongue, a spring claw or a spring hook, with the respective other of the two latching elements having a recess, a hole or a latching lug.

This causes a mechanically stable latching between the two latching members. At least one of the two latching members is preferably designed to be resilient (e.g. as a spring tongue, spring claw or spring hook) so that the corresponding latching member yields when the switch is opened and latches with the other latching member without great effort. The rear derailleur only has to overcome a small amount of force when opening in order to activate the closing lock.

Since several latching elements can also be provided on the two latching members, several spring tongues, several spring claws or several spring hooks can also be arranged on one latching member and several recesses, several holes or several latching lugs can also be arranged on the other latching member.

According to a further embodiment, it is provided that the locking element is arranged clamped between a spacer element and the lower part or between two spacer elements.

This enables a particularly simple assembly of the locking element and thus also of the entire closing lock. During assembly, the locking element is only clamped in by one or more spacer elements in the lower part and is thereby fixed by this or these on the lower part of the switch. The clamping connection between the locking element and the lower part also has the advantage that the lower part can be manufactured very easily. It then no longer necessarily has to be manufactured as a turned part, but can also be manufactured as a stamped part. This leads to a further reduction in costs.

According to a further embodiment, it is provided that the locking element is arranged clamped between a spacer element and the lower part and a part of the rear derailleur rests on the edge of the spacer element at least in the first switching position.

In addition to the previously mentioned advantages of simplified manufacture of the lower part as a stamped part and simplified assembly of the locking element, the use of a spacer element for clamping the locking element has the advantage that this allows the rear derailleur to be adjusted in height relatively easily. Depending on the height of the selected spacer element, the position of the switching mechanism can be regulated and thus, for example, the contact pressure can be set when the switch is closed.

Furthermore, the use of a spacer element, which is arranged between the switching mechanism and the locking element, has the advantage that an ohmic resistance can thereby be introduced between the locking element and the switching mechanism in a simple manner. The spacer element can be made of an electrically insulating material, for example. This prevents current from flowing through the locking element when the switch is in the closed state or during the opening process. This measure ultimately extends the service life of the locking element, since it is guaranteed in any case that the current flowing through the switch is introduced directly into the lower part via the switching mechanism.

The spacer element used to clamp the locking element is preferably designed as a spacer ring. Such a spacer ring can be used very easily in the interior space of the lower part, which is usually cylindrical, or can be clamped to it.

According to a further embodiment, the locking element is welded or soldered to the lower part, in particular to the inner floor surface of the lower part.

Although this is an alternative to clamping the locking element that is somewhat more complex in terms of production technology, the locking element can also be fixed to the lower part relatively easily in terms of production technology by welding or soldering. Thus, according to this alternative, a simple installation of the locking device is guaranteed. According to both alternatives (jamming or material connection), the locking element is permanently and captively fixed to the lower part.

In principle, it is also conceivable that the locking element is both materially connected to the lower part and is arranged clamped between this and a spacer element.

In a further embodiment, it is provided that the movable contact element has a latching lug in the region of its lower end facing the inner floor surface, which forms the second latching element.

In this case, a type of anchor is preferably arranged at the lower end of the movable contact member, in which a locking lug is formed circumferentially. When the switch is in the open state, i.e. when the switching mechanism is in the second switching position, this latching lug forming the second latching element latches with the first latching element arranged on the locking element. In this case, the first latching element can have, for example, one or more spring claws which, in the second switching position of the switching mechanism, latch with the latching lug arranged on the armature and thus permanently hold the switching mechanism in the second switching position.

According to the embodiment mentioned above, the contact element is preferably designed in the shape of a truncated cone, round or tapering between its lower end and the locking lug.

This simplifies the latching of the first latching element, which is arranged on the locking element, with the latching lug. When the switch is opened, the switching mechanism only has to overcome a small amount of pressure so that the latching lug arranged on the underside of the movable contact element snaps into the first latching element.

According to a further embodiment, it is provided that the locking element has a substantially annular section from which extends radially inwards two, three or more webs extend, at the ends of which a latching element is arranged, the latching elements together forming the first latching member.

According to this configuration, the locking element is therefore not configured as a full-surface disk. The bearing surface of the locking element is thus reduced. This is particularly advantageous when the locking element is arranged directly on the inner base surface of the lower part of the switch.

In this embodiment, the annular section of the locking element is used for clamping and/or integral attachment to the lower part. The radially inwardly extending webs each serve as a holder for a latching element.

For example, a spring tongue, a spring claw or a spring hook can be arranged at the radially inner ends of the webs, which protrudes upwards transversely to the respective web. By providing two or three such webs with spring tongues, spring claws or spring hooks arranged on their ends, a type of two- or three-legged holder can be realized as a counterpart to the second locking element arranged on the movable contact element.

In an alternative embodiment, it is provided that the locking element is designed in the shape of a circular disk and has a central hole through which the second latching element reaches in the second switching position of the rear derailleur in such a way that the second latching element latches with the circular disk-shaped arresting element.

The hole arranged centrally in the locking element thus forms part of the first locking member. In this case, it is preferable for several spring tongues, spring claws or spring hooks to be arranged on the underside of the movable contact element, which when the switch is opened reach through the hole in the locking element and hook onto the edge of the hole with the disk-shaped locking element in order to lock the switch in to hold it in its open position.

The disc-shaped locking element with a central hole is preferably arranged clamped between a first and a second spacer element, the first spacer element resting on the inner bottom surface of the lower part and a part of the rear derailleur rests on the edge on the second spacer element, at least in the first switching position.

With the help of these two spacers, you can easily adjust the height and resistance, as already mentioned above. Accordingly, the two spacer elements are also preferably made of electrically insulating material according to this embodiment.

The first spacer element arranged under the disk-shaped locking element serves as a support for the locking element. The second spacer element arranged above the disk-shaped locking element serves as a peripheral support for the rear derailleur. Together, the two spacer elements, which are preferably each designed as a spacer ring, clamp the locking element between them and thus fix it in its position.

In a further embodiment, the locking element is made of metal and in particular is made of sheet metal. The locking element is therefore a very inexpensive component which hardly increases the production costs of the switch.

In a manner known per se, the temperature-dependent switching mechanism preferably has a temperature-dependent snap-action disc with a geometric high-temperature configuration and a geometric low-temperature configuration, as well as a spring washer on which the movable contact element is arranged.

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

Furthermore, it is preferred that the spring washer is designed as a bistable spring washer and has two temperature-independent stable geometric configurations, wherein the Spring washer in its first configuration presses the moveable contact member against the first contact and in its second configuration holds the moveable contact member spaced from the first contact.

This has the advantage that the spring washer causes the closing force and thus the contact pressure between the movable contact element and the counter-contact (first contact) when the switch is in the closed state (in the first switching position of the switching mechanism). 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.

If the spring washer is designed as a bistable spring washer with two geometric configurations that are stable regardless of temperature, this has the additional advantage that the spring washer holds the switch in its open state after opening. Even if the bimetal dome then snaps back to its cryogenic configuration after the switch has cooled, the spring washer will hold the switch in its open position in addition to the mechanical locking mechanism.

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 The snap disk and the spring washer are fixed via their respective centers on the movable 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.

According to a further embodiment, it is preferred that the movable contact member comprises a movable contact part that interacts with the first contact, and that the spring washer interacts with the second contact, which is also preferred is that the spring washer, at least in its first configuration, is in electrical communication with the second contact via its edge.

This configuration 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 famous. It means that the snap-action disc is not live in any position of the switch, but that the load current of the electrical device to be protected flows through the spring washer.

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

The advantage here is that the switch can carry significantly higher currents than the one from the DE 10 2007 042 188 B3 known switches. When the switch is in the closed state, the current transmission element arranged on the contact element ensures the electrical short circuit between the two 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.

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

This measure is structurally known per se, it ensures that when the upper part is mounted on the lower part of the switch, the geometrically correct assignment between the first contact or the first and the second contact to the respective contact element or current transmission element is also produced.

Further advantages result from the description and the accompanying drawings.

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

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 eines zweiten Ausführungsbeispiels des erfindungsgemäßen Schalters in seiner Tieftemperaturstellung;

Fig. 4

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

Fig. 5

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

Fig. 6

eine Draufsicht von oben auf ein in dem erfindungsgemäßen Schalter verwendetes Arretierelement gemäß einem ersten Ausführungsbeispiel; und

Fig. 7

eine Draufsicht von oben auf das in dem erfindungsgemäßen Schalter verwendete Arretierelement gemäß einem zweiten Ausführungsbeispiel.

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

1

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

2

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

3

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

4

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

figure 5

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

6

a plan view from above of a locking element used in the switch according to the invention according to a first embodiment; and

7

a plan view from above of the locking element used in the switch according to the invention according to a second embodiment.

In 1 is a schematic, sectional side view of a switch 10 is shown, 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 to the base 16 by a bent or beaded edge 20.

in the in 1 The first exemplary embodiment shown is both the lower part 16 and the upper part 18 made of an electrically conductive material, preferably metal. Between the lower part 16 and the upper part 18 a spacer ring 22 is arranged, which supports the upper part 18 with the interposition of an insulating film 24 and keeps the upper part 18 spaced apart from the lower part 16 .

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

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

On the outside of the upper part 18, as in 1 shown, yet another insulation layer 26 may be attached.

The switching mechanism 14 has a spring washer 28 and a temperature-dependent snap-action disc 30 . The spring washer 28 is preferably designed as a bistable spring washer. Accordingly, it has two temperature-independent stable geometric configurations. In 1 their first configuration is shown. The temperature-dependent snap-action disk 30 is preferably also configured as a bistable snap-action disk. This has two temperature-dependent configurations, a high-temperature geometric configuration and a low-temperature geometric configuration. in the in 1 shown first switching position of the switching mechanism 14 is the snap disk 30 in its geometric low-temperature configuration.

The spring washer 28 rests with its edge 32 on a peripheral shoulder 34 formed in the lower part 16 and is clamped between this shoulder 34 and the spacer ring 22 . The edge 36 of the snap-action disc 30 rests on a further shoulder 38 which is also formed circumferentially in the lower part 16 .

With its center 40, the spring washer 28 is fixed to a movable contact member 42 of the switching mechanism 14. The snap disk 30 is also fixed with its center 44 on this contact member 42 . In this way, the temperature-dependent switching mechanism 14 is a captive unit made up of contact element 42, spring washer 28 and snap-action disc 30. When the switch 10 is installed, the switching mechanism 14 can thus be inserted directly into the lower part 16 as a unit.

The movable contact member 42 has a movable contact part 46 on its upper side. The movable contact part 46 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 1 As shown, the switch 10 is in its low temperature position in which the spring washer 28 is in its first configuration and the snap disk 30 is in its low temperature configuration. The spring washer 28 presses the movable contact part 42 against the first stationary contact 48.

In the closed low-temperature position of the switch 10 according to 1 is thus an electrically conductive connection between the first stationary contact 48 and the second stationary contact 50 via the movable contact member 42 and the spring washer 30 made.

If the temperature of the device to be protected increases and thus the temperature of the switch 10 and the snap-action disc 30 arranged therein, this snaps from the in 1 shown low-temperature configuration to their concave high-temperature configuration, which is shown in 2 is shown. In this snapping based the Snap disk 30 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 part 46 down and lifts the movable contact part 46 from the first stationary one Contact 48 off. As a result, it simultaneously bends the spring washer 28 downwards at its center 40, so that the spring washer 28 moves from its in 1 shown first stable geometric configuration in their in 2 shown snaps second geometrically stable configuration. 2 So shows the high-temperature position of the switch 10, in which it is open. The circuit is thus broken.

When the device to be protected and thus the switch 10 together with the snap-action disc 30 cool down again, the snap-action disc 30 snaps back into its low-temperature position, as shown, for example, in 1 is shown. Then the snap disk 30 would actually move the spring washer 28 back into its first in 1 move back the configuration shown and thus close the switch 10 again. However, in the case of the switch 10 according to the invention, this switch-back process is prevented by a closing lock 52 .

The closing lock 52 has an essentially plate-shaped or disk-shaped locking element 54, which in 1 and 2 shown first embodiment is integrally connected to the inner bottom surface 56 of the lower part 16. The locking element 54 has a first locking element 58, which is arranged on the movable contact element 42 with a second locking element 60 in the 2 shown high-temperature position of the switch 10 cooperates to lock the switching mechanism 14 mechanically.

At the in 1 and 2 shown first embodiment of the switch 10 according to the invention, the first locking member 58 has a plurality of spring claws 62. The second latching member 60 , on the other hand, is designed as a latching lug 64 that is formed circumferentially on a type of anchor 66 that is attached to the underside of the movable contact member 42 . The armature 66 is either attached to the contact member 42 or formed integrally therewith. The armature 66 thus forms part of the movable contact element 42.

The locking element 54 can be inserted into the lower part 16 as a separate component during the assembly of the switch 10 together with the first latching element 58 and can then be welded or soldered to the inner base surface 56 . As a result, the locking element 54 is fixed to the lower part.

Like in particular 2 As can be seen, the armature 66 latches with its detent 64 with the spring claws 62 arranged on the locking element 54 as soon as the snap disk 30 snaps over into its high-temperature configuration due to the temperature and the switch 10 is opened. A renewed closing of the switch 10 is then permanently prevented because the spring claws 62 of the locking element 54 permanently hold the armature 66 in the in 2 shown, regardless of whether or not the dome 30 snaps back to its geometric cryogenic configuration.

In order to enable the simplest possible latching between the two latching members 58, 60, the spring claws 62 are preferably designed to be elastically resilient. As soon as the armature 66 moves into the space between the spring claws 62 when the switch 10 is opened, these are spread radially outwards and then snap radially inwards again into the latching lug 64 provided on the armature 66 as soon as the movable contact element 42 together with the armature 66 moved down far enough (see 2 ).

The latching of the spring claws 62 with the latching lug 64 can be further facilitated if the lower end 63 of the movable contact member 42 or of the armature 66 is round, pointed or tapering in the shape of a truncated cone, since the armature 66 then has little resistance when the switch 10 is opened can be moved past the spring claws 62 until they engage with the locking lug 64 .

The locking element 54 can be designed in the form of a plate or disk, except for the first latching element 58 or the spring claws 62 . At the in 1 and 2 However, it is advantageous if the locking element 54 is configured only essentially in the form of a plate or disk with a plurality of recesses, as shown schematically in FIG 6 is shown.

in the in 6 In the exemplary embodiment shown, the locking element 54 has a circular section 68 from which three webs 70 extend radially inward. A spring claw 62 is arranged as a latching element at each end of the webs 70 . The three spring claws 62 act as a type of tripod which interacts with the latching lug 64 formed on the armature 66 when the switch 10 is in the open state. This creates a mechanically determined latching connection.

3 shows a second embodiment of the switch 10 according to the invention. The housing 12 and the switching mechanism 14 are basically constructed in the same way as in FIG 1 and 2 shown first embodiment. The closing lock 52 is basically the same as in the first embodiment. According to the second exemplary embodiment, however, the locking element 54 is not materially connected to the inner base surface 56 but instead is arranged clamped in the lower part 16 .

A spacer element 72 is used to clamp the locking element 54 . This spacer element 72 is preferably designed as a spacer ring. The spacer ring 72 can be fixed in the lower part 16 by means of a press fit, for example.

The essentially disk-shaped locking element 54 is thus clamped between the spacer element 72 and the inner bottom surface 56 of the lower part 16 . Since there is no need for a material connection between the locking element 54 and the lower part 16, this type of embodiment of the switch 10 is even easier to manufacture than the one in 1 and 2 shown version of the switch 10.

The spacer element 72 also offers the advantage that the position of the rear derailleur 14 can be adjusted depending on the height of the spacer element 72 . In this exemplary embodiment, snap-action disk 30 rests with its edge 36 on spacer element 72 .

The spacer element 72 is preferably made of electrically insulating material. At least the ohmic resistance of the spacer element 72 can be set in such a way that the snap-action disk lying on the spacer element 72 is prevented from moving 30 is traversed by current in the closed state of the switch. As a result, the service life of the snap disk 30 is extended.

The use of the spacer element 72 offers the further advantage that the shoulder 38 that would otherwise have to be provided can be omitted (cf. 1 and 2 ). The lower part 16 can therefore be manufactured much more easily. For example, it can be produced as a stamped part.

4 shows schematically a third embodiment of the switch 10 according to the invention. The housing 12 of the switch 10 is basically the same or at least similar to that according to FIG Figures 1-3 shown first two embodiments configured. However, the structure of the switching mechanism 14' and the structure of the closing lock 52' differs from the switch 10 according to the third exemplary embodiment to the first two exemplary embodiments.

The movable contact member 42' additionally includes a ring 74 surrounding the contact member 42'. This ring 74 is preferably pressed onto the contact member 42'.

The ring 74 has a peripheral shoulder 76 on which the snap disk 30 rests with its center 44 . The spring washer 28 is sandwiched between the ring 74 and the upper enlarged portion of the contact member 42'. In this way, the temperature dependent switching mechanism 14' is off 4 just as a captive unit of contact member 42 ', spring washer 28 and snap disk 30 as the derailleur 14 from the Figures 1-3 .

The second latching element 60' is arranged in the region of the lower end of the contact element 42'. This can be configured in one piece with the contact member 42', attached directly to the contact member 42', or attached to the ring 74.

The second locking element 60 ′ preferably has one or more spring tongues 78 here. These spring tongues 78 cooperate with the first locking element 58' of the locking element 54' in the sense of the closing lock 52' in the open state of the switch.

In this case, the locking element 54 ′ is designed as a circular disc with a central hole 80 . The locking element 54' is in 7 shown by way of example in a plan view from above.

In this exemplary embodiment, the hole 80 or the inner edge 82 of the locking element 54' surrounding the hole 80 acts as a second latching element 60 which interacts with the spring tongues 78 to implement the closing lock 52'.

The disc-shaped locking element 54 'is in the 4 shown embodiment is located locally between the derailleur 14 'and the inner bottom surface 56 of the base 16 as before. However, it does not rest directly on the inner floor surface 56 here. Instead, the locking element 54' is in 4 between two spacers 84, 86 clamped.

The first spacer element 84 rests on the inner bottom surface 56 of the lower part 16 and is arranged underneath the locking element 54'. The second spacer element 86 is arranged above the locking element 54'. On the second spacer element 86 is a part of the switching mechanism 14 ', in this case the outer edge 36 of the snap disk 30 on. Both spacer elements 84, 86 are preferably designed as spacer rings.

Otherwise, the closing lock 52' acts in the aforementioned manner and arrests the switching mechanism 14' after the switch 10 has been opened by means of the snap-action disc 30 due to the temperature.

At the in figure 5 shown fourth embodiment of the switch 10 according to the invention is the closing lock 52 'in the same or similar manner over the in 4 shown third embodiment of the switch 10 configured. According to the fourth exemplary embodiment, however, the switch 10 differs fundamentally in the construction of the housing 12'' and the switching mechanism 14''.

The lower part 16'' is again made of electrically conductive material. The flat upper part 18'', on the other hand, is here made of electrically insulating material. It is held to the base 16'' by a folded rim 88.

A spacer ring 22" is also provided here 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 Contact 50" on. The contacts 48'' and 50'' are formed as rivets which extend through the top 18'' and terminate externally in heads 92, 94 which are used to connect the switch 10 to the outside.

The movable contact member 42" here includes a current transmission member 96, which is in figure 5 The embodiment shown is a contact plate, the upper side of which has an electrically conductive coating, so that when it is in figure 5 shown system at the contacts 48" and 50" for an electrically conductive connection between the two contacts 48" and 50". The power transmission member 96 is connected to the spring washer 28 and the snap disk 30 by a rivet 98 which is also to be considered part of the contact member 42''.

The main advantage of the in figure 5 shown switch structure can be seen in the fact that in contrast to the first three in Figures 1-4 In the exemplary embodiments of the switch shown, no current flows here either through the spring washer 28 or through the snap-action disk 30 in the closed state of the switch. This flows only from the first external connection 92 via the first stationary contact 48", the current transmission element 96 and the second stationary contact 50" to the second external connection 94.

It goes without saying that not only the in 4 shown embodiment of the closing lock 52 'in the in figure 5 shown switch structure can be used, but also in Figures 1-3 shown versions of the closing lock 52.

Claims (15)

1. A temperature-dependent switch (10) having a housing (12), which comprises an upper part (18) and a lower part (16) that is closed by the upper part (18), wherein a first and a second stationary contact (48, 50) are arranged on the housing (12), wherein at least the first stationary contact (48) is arranged on the upper part (18), and wherein a temperature-dependent switching mechanism (14) having a movable contact member (42) is arranged in the housing (12),

   wherein the switching mechanism (14), in its first switching position, presses the movable contact member (42) against the first contact (48) and thereby produces an electrically conductive connection between the two contacts (48, 50) via the contact member (42) and, in its second switching position, keeps the movable contact member (42) spaced apart from the first contact (48),

   wherein a closing lock (52) is provided that prevents the switch (10) once having opened from closing again by locking the switching mechanism (14) permanently in its second switching position in a mechanical manner,

   characterized in that the closing lock (52) comprises a substantially disc- or plate-shaped locking element (54), which is arranged locally between the switching mechanism (14) and an inner bottom surface (56) of the lower part (16), is arranged clamped in the lower part and/or is connected to the lower part by means of a firmly bonded connection, and comprises a first latching member (58), which, in order to lock the switching mechanism (14), interacts in the second switching position with a second latching member (60) that is arranged on the movable contact member (42).
2. The switch according to claim 1, characterized in that the first latching member (58) or the second latching member (60) comprises a resilient tongue (78), a spring claw (62) or a spring hook, and wherein the respective other one of the two latching members comprises a recess, a hole (80) or a latching lug (64).
3. The switch according to claim 1 or 2, characterized in that the locking element (54) is arranged clamped between a spacer element (72) and the lower part (16) or between two spacer elements (84, 86).
4. The switch according to claim 1 or 2, characterized in that the locking element (54) is arranged clamped between a spacer element (72) and the lower part (16), and that a part of the switching mechanism (14) rests, at least in the first switching position, with its edge on the spacer element (72).
5. The switch according to claim 4, characterized in that the spacer element (72) is configured as a spacer ring.
6. The switch according to one of claims 1 to 5, characterized in that the movable contact member (42) comprises a latching lug (64) in the region of its lower end facing the inner bottom surface (56), which latching lug forms the second latching member (60).
7. The switch according to claim 6, characterized in that the movable contact member (42) is frustoconical, round or tapered between the lower end (63) and the latching lug (64).
8. The switch according to one of claims 1 to 7, characterized in that the locking element (54) comprises a substantially annular section (68) from which two, three or more webs (70) extend radially inwards, at the ends of which webs (70) a latching element (62) is arranged in each case, wherein the latching elements (62) together form the first latching member (58).
9. The switch according to one of claims 1 to 7, characterized in that the locking element (54) has a shape of a circular disc and comprises a central hole (80) which is penetrated by the second latching member (60) in the second switching position of the switching mechanism (14) in such a way that the second latching member (64) latches with the circular disc-shaped locking element (54).
10. The switch according to one of claims 1, 2 or 6 to 9, characterized in that the locking element (54) is arranged clamped between a first and a second spacer element (84, 86), wherein the first spacer element (84) rests on the inner bottom surface (56) of the lower part (16) and a part of the switching mechanism (14) rests, at least in the first switching position, with its edge on the second spacer element (86).
11. The switch according to claim 10, characterized in that the first and the second spacer element (84, 86) are each configured as a spacer ring.
12. The switch according to one of the claims 1 to 11, characterized in that the temperature-dependent switching mechanism (14) includes a temperature-dependent snap-action disc (30) having a geometric high-temperature configuration and a geometric low-temperature configuration as well as a spring disc (28) on which the movable contact member is arranged.
13. The switch according to claim 12, characterized in that the spring disc (28) is a bistable spring disc and has two temperature-independent stable geometric configurations, wherein, in its first configuration, the spring disc (28) presses the movable contact member (42) against the first contact (48) and, in its second configuration, keeps the movable contact member (42) spaced apart from the first contact (48).
14. The switch according to claim 12 or 13, characterized in that the snap-action disc (30) and the spring disc (28) are fixed to the movable contact member (42) via their respective centers (40, 44).
15. The switch according to one of claims 1 to 14, characterized in that the first contact (48) or each of the two contacts (48, 50") is arranged on an inner side (90) of the upper part (18).

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