Temperature-dependent switching mechanism and temperature-dependent switch having such a temperature-dependent switching mechanism

Abstract

To provide a temperature-dependent switching mechanism that is not susceptible to damage and can be pre-produced as a semi-finished product.SOLUTION: A temperature-dependent switching mechanism (10) for a temperature-dependent switch (100) includes a bimetallic element (12), a spring element (14), a conductive contact (16) on or secured to the spring element (14), and at least one retention pawl (18) on or secured to the spring element (14), the at least one retention pawl (18) has a support surface (34), the bimetallic element (12) is configured to snap from a low temperature configuration to a high temperature configuration upon exceeding a response temperature, the bimetallic element (12) is supported on the support surface (34) in its high temperature configuration.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a temperature-dependent switching mechanism for a temperature-dependent switch. The present invention further relates to a temperature-dependent switch having such a temperature-dependent switching mechanism.

Background Art

[0002] A number of temperature-dependent switching mechanisms and switches having such temperature-dependent switching mechanisms are already known in principle. Exemplary temperature-dependent switching mechanisms and switches are disclosed in German Patent 10 2011 119 632, German Patent 10 2022 118 405 and German Patent Publication 10 2013 017 232.

[0003] Such temperature-dependent switches are mainly used in a known manner for monitoring the temperature of a device. For this purpose, the switch is thermally contacted with the protected device, for example via one of its outer surfaces, so that the temperature of the protected device affects the temperature of the switching mechanism arranged inside the switch.

[0004] The switch is generally electrically connected in series to the supply circuit of the protected device via a connecting cable, so that below the response temperature of the switch, the supply current of the protected device flows through the switch.

[0005] In the switch disclosed in German Patent No. 10 2011 119 632, the switching mechanism is located inside a switch housing. The switch housing is formed from two parts. The switch housing has a lower part, which is firmly connected to a cover part via an insulating foil. The temperature-dependent switching mechanism located inside the switch housing comprises a spring element with a fixed movable contact and a bimetallic element positioned above the movable contact. The spring element presses the movable contact against a fixed opposing contact located inside the switch housing in the cover part. The outer edge of the spring element, configured as a snap-action spring disc, is supported by the lower part of the switch housing, and current flows from the lower part through the snap-action spring disc and the movable contact to the fixed opposing contact, and from the contact to the cover part.

[0006] Temperature-dependent bimetallic elements, in the case of the switch disclosed in German Patent No. 10 2011 119 632, are disk-shaped and often referred to as bimetallic snap-acting disks, and are essentially involved in the temperature-dependent switching behavior of the switching mechanism. These bimetallic elements are typically configured as multilayer active sheet-like devices consisting of two, three, or four interconnected components having different coefficients of thermal expansion. The connections between the individual metal or metal alloy layers in this type of bimetallic element are usually material locking or positive locking connections, achieved, for example, by rolling.

[0007] Such a bimetallic element has a first geometric configuration (low-temperature configuration) that is stable at low temperatures below the response temperature of the bimetallic element, and a second geometric configuration (high-temperature configuration) that is stable at high temperatures above the response temperature of the bimetallic element. The bimetallic element snaps (changes abruptly) from its low-temperature configuration to its high-temperature configuration in a temperature-dependent manner in the form of hysteresis.

[0008] Therefore, if the temperature of the bimetallic element rises above its response temperature as a result of the temperature rise of the device being protected, the bimetallic element snaps from its low-temperature configuration to its high-temperature configuration. This causes the bimetallic element to act on the spring element to lift the movable contact from the fixed opposing contact, resulting in the switch opening and the device to be protected being switched off and no longer heated.

[0009] Unless a reset lock is provided, the bimetallic element snaps back to its low-temperature configuration, and as a result, the switch closes again as soon as the temperature of the bimetallic element drops below the so-called reset temperature of the bimetallic element as a result of cooling the device to be protected.

[0010] In this low-temperature configuration, the bimetallic element is preferably mounted within the switch housing in a manner that does not apply mechanical force, and the bimetallic element is not used to conduct current. This has the advantage that the bimetallic element has a longer service life, and the switching point, i.e., the response or switching temperature of the bimetallic element, does not change even after many switching cycles.

[0011] Therefore, in the case of numerous temperature-dependent switches, it is preferable that the bimetallic elements are inserted into the switch housing as loose individual components during the manufacturing of the switch, and the bimetallic elements are positioned on a contact portion fixed to a spring element, for example, through a central through-hole provided therein. Only by closing the switch housing does the bimetallic element become fixed in place, and its position relative to the other components of the switching mechanism is defined. However, since several steps are required to insert the switch into the switch housing, the manufacturing of such switches in which the bimetallic elements are inserted individually has proven to be relatively cumbersome. Therefore, it is usually difficult to manufacture such switches automatically.

[0012] Therefore, in the switch disclosed in German Patent No. 10 2011 119 632, the bimetallic element is connected to a contact that is pre-fixed to a spring element (outside the switch housing). For this purpose, the bimetallic element is placed on the contact, and then the upper collar of the contact is bent. As a result, not only is the spring element fixed to the contact, but the bimetallic element is also constrained and held by the contact.

[0013] Thus, the switching mechanism, consisting of bimetallic elements, spring elements, and contact parts, can be manufactured in advance as a semi-finished product, forming a restraining unit that can be stored separately as bulk material. When manufacturing the switch, the switching mechanism can be inserted into the switch housing as a restraining unit in just one step. This simplifies switch production many times over.

[0014] In the switch disclosed in German Patent No. 10 2011 119 632, the spring element is welded or soldered to the contact portion to achieve the best possible electrical contact between the two components. However, it has been shown that the welded or soldered connection between the contact portion and the spring element may break, especially when the switch is stored in bulk as a semi-finished product. Such a defective switch can, of course, no longer be inserted. In particular, the problem is that such defects can only be detected after the switch has been assembled, and only then is it possible to test the function of the switching mechanism.

[0015] In particular, the latter point is improved in the switching mechanism disclosed in German Patent No. 10 2022 118 405. The switching mechanism disclosed in this document comprises a further switching mechanism housing in which a switching mechanism unit, including a bimetallic element, a spring element, and contacts, is held constrained but with play. This further switching mechanism housing not only enables the pre-production of the switching mechanism as a semi-finished product but also protects the fragile components of the switching mechanism from damage, especially during storage. This also simplifies the installation of the switching mechanism in a switch. Furthermore, the further switch housing has the advantage that the snapping behavior of the bimetallic element can already be tested within the switch housing, so the switching mechanism can be functionally tested before being installed in a switch.

[0016] A similarly advantageous solution is disclosed in German Patent Publication No. 10 2013 017 232. The temperature-dependent switching mechanism disclosed in this document comprises an annular frame in which a bimetallic element and a spring element are held in a constrained state. This configuration also protects the fragile devices of the switching mechanism during storage. Furthermore, it allows for functional testing of the switching mechanism even before mounting it in a switch or switching mechanism housing.

[0017] While the latter two solutions have proven particularly advantageous, there is still room for further improvement. Specifically, the manufacturability of the switching mechanism could be improved, and its size could be further reduced. Furthermore, further simplification and improvement should lead to even greater cost savings. [Overview of the project] [Problems that the invention aims to solve]

[0018] Therefore, an object of the present invention is to provide a temperature-dependent switching mechanism that further improves upon the points described above. In particular, the object is to provide a temperature-dependent switching mechanism that is not susceptible to damage leading to defects in the switching mechanism, can be pre-produced as a semi-finished product, and can be stored as bulk material. Nevertheless, a switching mechanism pre-produced as a semi-finished product is as easy as possible to use in a temperature-dependent switch and allows for the manufacture of the switching mechanism with as few steps as possible. It should also be possible to test the function of the switching mechanism before mounting it in a switch. [Means for solving the problem]

[0019] According to the present invention, this objective is solved by a temperature-dependent switching mechanism having the following: Bimetallic elements, Spring element and, A conductive contact portion provided on or fixed to the spring element, It comprises at least one retaining claw provided on or fixed to the spring element, At least one retaining claw has a support surface, The bimetallic element is configured to snap from a low-temperature configuration to a high-temperature configuration when the response temperature is exceeded, and the bimetallic element is supported on the support surface in its high-temperature configuration.

[0020] Accordingly, the switching mechanism according to the present invention comprises one or more retaining claws, which are provided on or fixed to a spring element and serve to hold the bimetallic element. At least one retaining claw not only holds the bimetallic element and prevents it from detaching from the switching mechanism, but also simultaneously protects the bimetallic element during bulk storage of the switching mechanism.

[0021] At least one retaining claw has a support surface on which the bimetal element is supported in its high-temperature configuration. This has the advantage that a functional test can be carried out using the switching mechanism according to the invention even before the switching mechanism is installed in the switch. The bimetal element can assume both its states / configurations (low-temperature configuration and high-temperature configuration) within the switching mechanism without the need for further components.

[0022] Compared with the initially mentioned prior-art switching mechanism, the switching mechanism according to the invention is significantly more compact, simpler, and in particular, consists of fewer components. Due to the provision of at least one retaining claw, the housing of the switching mechanism as proposed in German Patent 10 2022 118 405 is no longer necessary. Since at least one retaining claw is provided on the spring element according to the invention, for example, integrally formed with the spring element or fixed to the spring element, the switching mechanism according to the invention is also significantly smaller or more compact than the switching mechanism disclosed in German Patent 10 2022 118 405.

[0023] A ring-shaped frame as proposed in German Patent Publication 10 2013 017 232 is also no longer necessary according to the invention. Instead, at least one retaining claw is used in the switching mechanism according to the invention. Due to the support surface arranged thereon, the bimetal element according to the invention can be directly supported on the retaining claw in its high-temperature configuration, which is advantageous in contrast to the switching mechanism disclosed in German Patent Publication 10 2013 017 232 in which the bimetal element is directly supported on the spring element in its high-temperature configuration. This bimetal element, in particular, releases the spring element and makes the switching mechanism as a whole more durable.

[0024] In this way, the above object is completely solved.

[0025] In the improved example, the bimetal element, the spring element and the contact part form a switching mechanism unit that is held in a mutually constrained manner.

[0026] Therefore, the individual parts of the switching mechanism unit cannot come off from each other. On the other hand, this has the advantage that the switching mechanism can be pre-manufactured as a semi-finished product and can be stored more easily and reliably as a bulk material or on a conveyor belt. Furthermore, the switching mechanism having all its individual parts can be inserted as a whole into the switch housing, which simplifies the assembly of the switch and thus facilitates automation.

[0027] In a further improved form, the bimetal element is captured and held by the contact part and / or is captured and held by the spring element by means of at least one retaining claw.

[0028] This prevents loss of the bimetal element, especially during storage on a belt or as a bulk material. Also, when the switching mechanism is attached to and used in the switch, it ensures that the bimetal element does not come off from the switching mechanism. The most mechanically stable and safe way to hold the bimetal element is achieved when it is constrained by the contact part and by the spring element by means of at least one retaining claw.

[0029] In a further improved form, at least one retaining claw projects in one direction from the first side surface of the spring element facing the bimetal element.

[0030] In other words, at least one retaining claw projects from the spring element on the same side where the bimetal element is arranged. The advantage of at least one retaining claw projecting on one side is that the embodiment of the switching mechanism is as space-saving as possible.

[0031] In the case of several retaining claws, it is preferable that they all project to one side from the same (first) side surface of the spring element.

[0032] In a further improved form, at least one retaining claw protrudes from a first side of the spring element in a first direction, and the support surface is oriented laterally with respect to the first direction and faces the spring element.

[0033] In this case, the term "lateral" does not necessarily mean orthogonal or perpendicular. Instead, it is understood to mean any type of orientation that is not parallel. Therefore, oblique orientation at an angle not equal to 0° also falls under the term "lateral."

[0034] According to the improved example described above, at least one retaining claw preferably comprises a first portion that protrudes from the spring element and extends in a first direction, and a second portion that is connected to the first portion, extends laterally relative to the first portion, and is positioned such that its support surface faces the spring element. Particularly preferably, at least one retaining claw has an inverted (upside down) L-shaped cross-section.

[0035] In a further improved form, at least one retaining claw comprises at least two retaining claws.

[0036] In this improved configuration, at least two retaining claws are preferably spaced apart from each other on the spring element. Particularly preferably, at least two retaining claws in this improved configuration are each at the same distance from the central axis of the spring element. In the case of three or more retaining claws, they are preferably evenly distributed on the spring element, resulting in rotational symmetry about the central axis.

[0037] Some individual retaining claw embodiments are typically easier to manufacture and more cost-effective than relatively large, continuous retaining claws, which extend, for example, along the entire circumference of the bimetallic element, or along a large portion of the circumference of the bimetallic element (i.e., more than 50% of the circumference of the bimetallic element).

[0038] In a further improvement, at least one retaining claw is integrally connected to the spring element or fixed to the spring element by a material locking mechanism.

[0039] Therefore, at least one retaining claw can be formed integrally with the spring element, for example. Alternatively, it is preferable that at least one retaining claw is welded or soldered to the spring element. This creates a mechanically very stable retaining claw that is inseparably connected to the spring element.

[0040] In a further improved form, the spring element has an outer edge, and at least one retaining claw is spaced apart from the outer edge.

[0041] Preferably, the outer edge is the circumferential outer edge from which at least one retaining claw is spaced. Particularly preferably, at least one retaining claw is at a distance smaller than the outer edge of the spring element from the central axis of the spring element. In other words, it is preferable that at least one retaining claw is offset radially inward with respect to the outer edge of the spring element, and that this spring element is, for example, disc-shaped, particularly circular disc-shaped.

[0042] This has the advantage that the switching mechanism according to the present invention can be fixed in place by clamping the outer edge of the spring element between two parts of the switch housing when the switch is installed, thus allowing the switch to be very easily fixed within the switch housing. This does not impair the function of at least one retaining claw.

[0043] In further improvements, the outer edge lies within a single plane, and the radially inner region of the spring element is curved.

[0044] This makes it even easier to secure the switching mechanism within the switch housing. Furthermore, the curved inner region of the spring element allows for sufficient degrees of freedom of movement of the spring element, thereby enabling it to move together with the bimetallic element during switching operation.

[0045] In a further improvement, the spring element has a first configuration when the bimetallic element is in its low-temperature configuration, and when the bimetallic element snaps into its high-temperature configuration, the spring element is brought into a second configuration by the bimetallic element.

[0046] Preferably, the spring element is a snap-action spring disc having two different configurations or states, similar to a bimetallic element. It is particularly preferable that the two configurations / states of the spring element are mechanically stable. However, unlike the two configurations of a bimetallic element, the two configurations / states of the spring element are temperature-independent.

[0047] In a further improved example, the spring element, along with at least one retaining claw, forms an open housing in which the bimetallic element is positioned to be accessible from the outside, the open housing at least partially enclosing the bimetallic element from a first side, a second side opposite the first side, and a circumferential side extending laterally between the first and second sides.

[0048] As a result, the bimetallic element is enclosed and positioned to some extent within a housing formed by a spring element and at least one retaining claw. This provides good protection for the bimetallic element, which is particularly advantageous when the switching mechanism is housed in bulk. This type of "housing" preferably encloses the bimetallic element from at least partially all sides, while the bimetallic element remains accessible from the outside, which is very important for the function of the switching mechanism.

[0049] More specifically, the open housing formed by the spring element together with at least one retaining claw has an opening on the second side surface, the inner diameter of which is smaller than the outer diameter of the bimetallic element and is measured parallel to the bimetallic element.

[0050] This ensures in a simple way that the bimetallic element is not released from at least one retaining claw. Thus, the bimetallic element is constrained and held by the spring element.

[0051] In further improvements, the switching mechanism is rotationally symmetric with respect to its central axis.

[0052] This also simplifies the installation of the switching mechanism, as it can be inserted into the switch housing of the switch in any orientation relative to its central axis. Furthermore, the symmetrical orientation of the switching mechanism ensures optimal force distribution when the switch is closed.

[0053] In a further improved form, the bimetallic element has an opening with a protruding contact portion. The bimetallic element is preferably disc-shaped. The aforementioned opening is preferably inserted into the center of the bimetallic element, and the bimetallic element is positioned on the contact portion with this opening.

[0054] In further improved forms, the spring element preferably includes a conductive material.

[0055] This has the advantage that the spring element can be used as a conductive component so that current flows through the spring element when the switch is closed. The current does not need to flow through the bimetal element when the switch is closed, which reduces the load on the bimetal element and has a positive effect on its service life.

[0056] As stated at the outset, the present invention relates not only to a temperature-dependent switching mechanism but also to a temperature-dependent switch into which the switching mechanism according to the present invention is inserted. The improvements and features defined in the dependent claims described above are understood to be related not only to the switching mechanism according to the present invention but also to the switch according to the present invention.

[0057] In an improved example of a temperature-dependent switch, a switch housing is provided in which the temperature-dependent switching mechanism is located, comprising a lower section and a cover section, with a spring element clamped between the lower section and the cover section. Preferably, the outer edge of the spring element is clamped between the lower section and the cover section of the switch housing. Thus, the switch is relatively easy to install and mechanically stable.

[0058] It should be understood that the features described above and those described below can be used not only in the combinations shown in each case, but also in other combinations, or individually, without departing from the scope of the present invention. [Brief explanation of the drawing]

[0059] Embodiments of the present invention are shown in the drawings and will be described in more detail in the following description. [Figure 1] This is a schematic cross-sectional view of a temperature-dependent switching mechanism according to a first embodiment of the present invention, wherein the switching mechanism is in a first switching state. [Figure 2] Figure 1 is a schematic cross-sectional view of a temperature-dependent switching mechanism, where the switching mechanism is in the second switching state. [Figure 3] This is a schematic cross-sectional view of a temperature-dependent switching mechanism according to a second embodiment of the present invention, wherein the switching mechanism is in a first switching state. [Figure 4] This is a schematic plan view of a spring element that can be used in a temperature-dependent switching mechanism according to the present invention. [Figure 5] This is a schematic cross-sectional view of a temperature-dependent switch according to one embodiment of the present invention, where the switch is in a low-temperature state. [Figure 6] Figure 5 shows a schematic cross-sectional view of a temperature-dependent switch, with the switch in its high-temperature state. [Figure 7] This is a schematic cross-sectional view of a temperature-dependent switch according to a further embodiment of the present invention, where the switch is in its low-temperature state. [Figure 8]Figure 7 shows a schematic cross-sectional view of a temperature-dependent switch, where the switch is in a high-temperature state. [Modes for carrying out the invention]

[0060] Figures 1 and 2 show schematic cross-sectional views of a first embodiment of the switching mechanism according to the present invention. Figure 1 shows the switching mechanism in a low-temperature state. Figure 2 shows the switching mechanism in a high-temperature state. In each case, the entire switching mechanism is indicated by reference numeral 10.

[0061] The switching mechanism 10 is a temperature-dependent switching mechanism. The switching mechanism 10 has a configuration consisting of many parts. The switching mechanism 10 comprises a bimetallic element 12, a spring element 14, a conductive contact portion 16, and at least one retaining claw 18.

[0062] As the name suggests, the bimetallic element 12 is a bimetallic element. The spring element 14 and the contact portion 16 are made of a conductive material, preferably metal. It is also preferable that at least one retaining claw 18 is made of metal. However, at least one retaining claw 18 does not necessarily have to be made of a conductive material and may be made of a non-conductive material.

[0063] In the embodiments shown in Figures 1 and 2, the bimetallic element 12 is essentially a circular disk. Therefore, the bimetallic element 12 is also called a bimetallic disk. Due to its physical properties, the bimetallic element 12 is also called a bimetallic snap-action disk.

[0064] In the illustrated embodiment, the bimetallic element 12 has a central opening 20, and the bimetallic element 12 is positioned on the contact portion 16 together with the central opening. In the embodiment shown in Figures 1 and 2, the bimetallic element 12 is positioned covering the contact portion 16 without its opening 20 being firmly connected to the contact portion 16. In other words, the bimetallic element 12 and the contact portion 16 are loosely coupled to each other in this respect and are movable relative to each other.

[0065] In this embodiment, the contact portion 16 is fixed to the spring element 14. More precisely, in this embodiment, the contact portion 16 is connected to the spring element 14 by a material locking mechanism. The contact portion 16 is, for example, soldered or welded to the spring element 14. For better centering, the contact portion 16 is provided with an extension 22 at its end, which, together with the extension 22, is inserted into an opening 24 provided in the center of the spring element 14. Approximately in the middle, the contact portion 16 is provided with a collar 26, and together with the bottom side of the collar, the contact portion 16 lies flat on the upper side of the spring element 14. The material locking connection between the spring element 14 and the contact portion 16 is preferably provided on the bottom side of the collar 26. The collar 26 provided on the contact portion 16 also serves to support the bimetallic element 12 in its high-temperature configuration (see Figure 2), as will be described in more detail below.

[0066] In this regard, it should be noted that the contact portion 16 can be integrally connected to the spring element 14 instead of being connected by a material locking method. In other words, the spring element 14 and the contact portion 16 can be formed integrally. In this case, it is preferable that the contact portion 16 be formed as a protruding portion that extends from the upper side of the spring element 14.

[0067] At least one retaining claw 18 is positioned in the region of the outer edge 28 of the spring element 14. In the embodiments shown in Figures 1 and 2, at least one retaining claw is fixed to the spring element 14 in a material locking manner, for example by welding or soldering.

[0068] At least one retaining claw 18 protrudes in one direction from the upper side 30 of the spring element 14, which in this case is also called the first side 30 of the spring element 14. This first side 30 of the spring element 14 is the side of the spring element 14 that faces the bimetallic element 12.

[0069] More precisely, at least one retaining claw 18 protrudes from the first side surface 30 of the spring element 14 in a first direction 32, which corresponds to the vertical direction in Figures 1 and 2. A support surface 34 is provided inside the at least one retaining claw 18. This support surface 34 extends laterally, preferably perpendicular to the first direction 32. In its high-temperature state, the bimetallic element 12 is supported by its outer edge 36 on this support surface 34, as will be described in more detail below (see Figure 2).

[0070] Together with at least one retaining claw 18, the spring element 14 forms a partially open housing, in other words, within the housing the bimetallic element 12 is constrained, positioned and held, but accessible from the outside. This open housing formed by the spring element 14 and at least one retaining claw 18 at least partially encloses, in each case, the first side 38 of the bimetallic element 12 facing the first side 30 of the spring element 14, the second side 40 on the opposite side of the bimetallic element 12, and the peripheral side 42 of the bimetallic element extending laterally to the first and second sides 38, 40. The open housing formed by the spring element 14 together with at least one retaining claw 18 has an opening 44 on the side facing the second side 40 of the bimetallic element 12, through which the movable contact portion 16 is accessible from the outside.

[0071] The inner diameter of this opening 44 is smaller than the outer diameter of the bimetal element 12, measured parallel to the bimetal element 12. This ensures that the bimetal element 12 is constrained and held on the spring element 14 by at least one retaining claw 18. The bimetal element 12, the spring element 14, and the contact portion 16 thus form a captureably held switching mechanism unit.

[0072] In the low-temperature state of the switching mechanism 10 shown in Figure 1, the bimetallic element 12 is convexly curved on its second side surface 40 (the upper side of the bimetallic element 12). Similarly, the radially inner region 46 of the spring element 14 is convexly curved on its first side surface 30 (the top side of the spring element 14) in the low-temperature state shown in Figure 1. In other words, in the low-temperature state of the switching mechanism 10, both the radially inner region 46 of the bimetallic element 12 and the spring element 14 are curved upward (see Figure 1). In this shifted position, the bimetallic element 12 is loosely resting from above on the collar 26 of the contact portion 16. Preferably, the free outer edge 36 of the bimetallic element 12 is formed with virtually no force applied and does not have contact with the spring element 14 and / or at least one retaining claw 18.

[0073] From this switching state of the switching mechanism 10, when the temperature of the switching mechanism 10 rises above the response temperature of the bimetal element 12, the bimetal element 12 snaps (changes rapidly) from the low-temperature state shown in Figure 1 to the high-temperature state shown in Figure 2. Here, the second side surface 40 of the bimetal element 12 (the upper side of the bimetal element 12) is curved in a concave shape. As a result, the bimetal element 12 is supported by its outer edge 36 on a support surface 34 positioned on at least one retaining claw 18. At the same time, the bimetal element 12 presses the contact portion 16 with its inner edge 48 in the direction of the spring element 14. In other words, both the bimetal element 12 and the spring element 14 curve downward, and as a result, not only does the bimetal element 12 curve concavely on its second side surface 40 (upper side), but the spring element 14 also curves concavely on its first side surface 30 (upper side).

[0074] At least one retaining claw 18 acts as a kind of contact point in the high-temperature state of the switching mechanism 10, which supports the bimetallic element 12. Together with its devices 12, 14, 16, and 18, the switching mechanism 10 also restrictively holds the switching mechanism unit in the low-temperature state and forms together. Therefore, functional checks of the switching mechanism 10 can also be performed without further devices, and in particular, without the need to install the switching mechanism 10 in a temperature-dependent switch. Thus, the switching mechanism 10 shown in Figures 1 and 2 forms a separately functioning, storable semi-finished product.

[0075] Figure 3 shows a schematic cross-sectional view of a second embodiment of the switching mechanism 10 according to the present invention. The basic structure and operating mode of the switching mechanism 10 are the same as those of the first embodiment shown in Figures 1 and 2. The basic configuration of the switching mechanism 10 is also the same as that of at least the first embodiment. However, one difference is that at least one retaining claw 18 is integrally connected to or formed integrally with the spring element 14. Preferably, the spring element 14 and at least one retaining claw 18 are formed from thin sheet metal.

[0076] A further difference in this second embodiment shown in Figure 3 is that the contact portion 16 is configured here as a kind of rivet, which is connected to both the bimetallic element 12 and the spring element 14. In the second embodiment shown in Figure 3, the bimetallic element is not only constrained to the spring element by at least one retaining claw 18, but is also constrained and held by the contact portion 16. A support ring 50 can be placed between the bimetallic element 12 and the spring element 14 on the contact portion 16 configured as a rivet. However, the support ring is not necessarily required.

[0077] Figure 4 is a top-down plan view of the spring element 14 in an embodiment of the switching mechanism 10 shown in Figure 3. As can be seen, the spring element 14 is essentially a circular disk shape, and various recesses 52 are provided to reduce electrical resistance and save material. Instead of a single retaining claw 18 extending entirely around the circumference, three retaining claws 18 are provided here, which are dispersed apart from each other. More precisely, the three retaining claws are regularly distributed around the spring element 14. It is also understood that, in principle, two or more retaining claws 18 can be provided. Similarly, if at least one retaining claw 18 extends over a larger portion of the circumference of the spring element 14, then a single retaining claw 18 may serve as the contact point for the bimetallic element 12.

[0078] At least one retaining claw 18 is preferably positioned at a certain distance from the outer edge 28 of the spring element 14. Adjacent to this outer edge 28, the spring element 14 preferably has a peripheral region 58 that lies in a plane, i.e., is flat or planar. The radial inner region 46 of the spring element 14 is formed by three radially extending webs 54 and a central region 56 in the embodiment shown in Figure 4, and the inner region 46 is curved.

[0079] The flat outer edge region 58 of the spring element 14 provides the advantage of being as easy to install and secure as possible within the temperature-dependent switch, as will be described in more detail below.

[0080] The spring element 14 is rotationally symmetric about the central axis 60. Similarly, it is preferable that the entire switching mechanism 10 is also rotationally symmetric about the central axis 60. Therefore, the switching mechanism 10 can be inserted into the switch housing of a switch at any position rotating about the central axis 60. This makes the assembly of the switching mechanism 10 many times simpler.

[0081] Figures 5 and 6 show a first embodiment of a temperature-dependent switch in which the switching mechanism 10 according to the present invention is used. Figure 5 shows the switch in a low-temperature state. Figure 6 shows the switch in a high-temperature state. In both cases, the switch as a whole is denoted by reference numeral 100. The switch 100 includes a switch housing 62 that functions as a housing for the switching mechanism 10. The switch housing 62 consists of a pot-shaped lower portion 64 and a cover portion 66, the cover portion of which is held on the lower portion 64 by a bent or flanged upper edge of the lower portion 64.

[0082] In the embodiments shown in Figures 5 and 6, both the lower portion 64 and the cover portion 66 are made of a conductive material, preferably metal. An insulating foil 68 is placed between the lower portion 64 and the cover portion 66. The insulating foil 68 electrically insulates the lower portion 64 from the cover portion 66. The insulating foil 68 also provides a mechanical seal that prevents liquids or impurities from entering the inside of the housing from the outside.

[0083] Since the lower part 64 and the cover part 66 are made of conductive material, thermal contact with the electrical device to be protected can be established through their outer surfaces. The outer surfaces can also be used for the electrical connections of the switch 100. For example, the outer surface 65 of the lower part 64 functions as a first electrical terminal, and the outer surface 67 of the cover part 66 functions as a second electrical terminal of the switch 100.

[0084] The switching mechanism 10 is clamped and positioned between the lower part 64 and the cover portion 66. More precisely, the switching mechanism 10 is clamped and positioned between the spacer ring 70 and the cover portion 66. For this purpose, the outer edge region 58 of the spring element 14 rests on the spacer ring 70 and is clamped from the opposite side by the cover portion 66.

[0085] Furthermore, the switching mechanism 10 has at least one retaining claw 18 that rests on the inner circumference of the spacer ring 70. Thus, with the help of the spacer ring 70, the switching mechanism 10 can be both fixed and centered. As a result, the movable contact portion 16 of the switching mechanism 10 is oriented relative to a fixed opposing contact portion 72 located inside the lower part 64 of the switch housing 62. This opposing contact portion 72 is also referred to in this case as the stationary contact portion.

[0086] In the low-temperature state of switch 100 shown in Figure 5, also called the closed state of switch 100, the switching mechanism 10 establishes a conductive connection between the lower part 64 and the cover part 66, and consequently between the two external connection surfaces 65 and 67 of switch 100. The conductive contact between the two external connection surfaces 65 and 67 of switch 100 is established, in particular, via the spring element 14 and the movable contact part 16 which interacts with the fixed contact part 72. The contact pressure between the movable contact part 16 and the fixed contact part 72 is generated by the spring element 14. In this state, the bimetallic element 12 is housed in the switching mechanism 10 with more or less no force applied to it.

[0087] When the temperature of the protected device, and consequently the temperature of the switch 100, rises to or above the switching temperature of the bimetallic element 12, the bimetallic element 12 snaps from its low-temperature state shown in Figure 5 to its high-temperature state shown in Figure 6. During this snapping motion, the bimetallic element 12 is supported by its outer edge 36 on a support surface 34 provided on at least one retaining claw 18, and its inner edge 48 presses upward against the movable contact portion 16 together with the spring element 14. As a result, the spring element 14 bends upward along with its center, thereby lifting the movable contact portion 16 away from the fixed contact portion 72. Thus, the circuit is interrupted, and therefore the switch 100 opens.

[0088] The device to be protected, and consequently the bimetallic element 12, along with the switch 100, cools down again, and when the bimetallic element 12 reaches a reset temperature, also known as the switchback temperature, as shown in Figure 5, it snaps back to that low-temperature state. This enables reversible switching behavior.

[0089] Of course, it is also possible to prevent switch 100 from being switched back after being snapped to a high temperature state by a corresponding locking device. In particular, many such locking devices used in one-time switches where switchback should be prevented are already known from the prior art.

[0090] Figures 7 and 8 show further embodiments of the switch 100 according to the present invention, and again are schematic cross-sectional views of the switch 100 in both a low-temperature state (Figure 7) and a high-temperature state (Figure 8).

[0091] The spacer ring 70' here has a slightly different shape. However, a major difference from the embodiments shown in Figures 5 and 6 is that the opposing contact portion 72 is not configured as a fixed contact portion here, but is located on an opposing spring element 74. This opposing spring element 74 optimally compensates for manufacturing tolerances. On the other hand, the contact pressure can be increased in the closed state of the switch (see Figure 7) because the opposing spring element 74 opposes the spring element 14, and therefore increases the force with which the two contact portions 16, 72 are pressed together. However, the switching principle remains the same as that previously described with reference to the embodiments shown in Figures 5 and 6.

[0092] It is understood that various further modifications can be made to both the switching mechanism 10 itself and the switch housing 62 without departing from the scope of the present invention. Furthermore, the shape of the at least one retaining claw shown in this case can be changed almost freely, which is why the term “retaining claw” should be interpreted broadly in this case. Functionally, at least one retaining claw 18 functions as a holder for the bimetallic element 12, the latter being supported at its edge 36, particularly in the high-temperature state of the switching mechanism 10.

Claims

1. A temperature-dependent switching mechanism (10) for a temperature-dependent switch (100), Bimetallic element (12), Spring element (14), A conductive contact portion (16) provided on or fixed to the spring element (14), It comprises at least one retaining claw (18) provided on or fixed to the spring element (14) and having a support surface (34), Here, the bimetallic element (12) is configured to snap from a low-temperature configuration to a high-temperature configuration when the response temperature is exceeded, and the bimetallic element (12) is supported on the support surface (34) in its high-temperature configuration. The switching mechanism (10) is rotationally symmetric about a central axis (60), and the bimetallic element (12) is characterized by having a central opening (20) from which the contact portion (16) protrudes.

2. The temperature-dependent switching mechanism (10) according to claim 1, wherein the bimetallic element (12), the spring element (14), and the contact portion (16) are held together in a constrained manner to form a switching mechanism unit.

3. The temperature-dependent switching mechanism (10) according to claim 1, wherein the bimetallic element (12) is constrained and held at the contact portion (16) and / or constrained and held at the spring element (14) by the at least one retaining claw (18).

4. The temperature-dependent switching mechanism (10) according to claim 1, wherein at least one retaining claw (18) protrudes in one direction from a first side surface (30) of the spring element (14) facing the bimetallic element (12).

5. The temperature-dependent switching mechanism (10) according to claim 4, wherein at least one retaining claw (18) protrudes from the first side surface (30) of the spring element (14) in a first direction (32), and the support surface (34) is positioned laterally with respect to the first direction (32) and faces the spring element (14).

6. The temperature-dependent switching mechanism (10) according to claim 1, wherein the at least one retaining claw (18) includes at least two retaining claws (18).

7. The temperature-dependent switching mechanism (10) according to claim 1, wherein the at least one retaining claw (18) is a single retaining claw (18) that extends along at least a large portion of the circumference of the spring element (14) or along the entire circumference of the spring element (14).

8. The temperature-dependent switching mechanism (10) according to claim 1, wherein at least one retaining claw (18) is integrally connected to the spring element (14) or fixed to the spring element (14) by welding or soldering.

9. The temperature-dependent switching mechanism (10) according to claim 1, wherein the spring element (14) has an outer edge (28) and at least one retaining claw (18) is positioned spaced apart from the outer edge (28).

10. The temperature-dependent switching mechanism (10) according to claim 9, wherein the outer edge (28) is in a single plane and the radially inner region (46) of the spring element (14) is curved.

11. The temperature-dependent switching mechanism (10) according to claim 1, wherein the spring element (14), together with the at least one retaining claw (18), forms an open housing in which the bimetallic element (12) is disposed, and is accessible from the outside, the open housing at least partially surrounding the bimetallic element (12) with a first side surface (38), a second side surface opposite to the first side surface (38), and a circumferential side surface (42) extending laterally from the first and second side surfaces (38, 40).

12. The temperature-dependent switching mechanism (10) according to claim 11, wherein the open housing formed by the spring element (14) together with at least one retaining claw (18) has an opening (44) on the second side surface (40), the inner diameter of the opening (44) being smaller than the outer diameter of the bimetallic element (12) measured parallel thereto.

13. A temperature-dependent switch (100) having a temperature-dependent switching mechanism according to any one of claims 1 to 12.

14. The temperature-dependent switch (100) according to claim 13, wherein the switch (100) includes a switch housing (62) in which the temperature-dependent switching mechanism (10) is disposed, the switch housing includes a lower part (64) and a cover part, and the spring element (14) is clamped between the lower part (64) and the cover part (66).

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