Temperature-dependent switch

Abstract

To provide a temperature-dependent switch which is composed of few components and easy to install.SOLUTION: A temperature-dependent switch includes: a switching mechanism which is arranged in a switch housing, which includes a movable contact part, and a bimetal element and a spring element interacting with the movable contact part, which, in a low-temperature state, presses the movable contact part against a contact surface arranged inside the switching housing to establish an electrical connection between first and second terminals of the switch, and which, in a high-temperature state, keeps the movable contact part spaced apart from the contact surface to interrupt the electrical connection between the first and second terminals; and a spacer element arranged between a lower part and a cover part of the switch housing. One section of the spring element is arranged between the spacer element and the switch housing and is fixed in a predetermined position by an interaction of the spacer element and the switch housing, and one section of the bimetal element is arranged between the spring element and the spacer element and is supported on the spacer element in the high-temperature state of the switching mechanism.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a temperature dependent switch. [Background technology]

[0002] A large number of temperature-dependent switches are already known in principle. Exemplary temperature-dependent switches are disclosed in DE 10 2013 109 291 A1 and DE 10 2011 119 637 A1.

[0003] Such temperature-dependent switches are primarily used in a known manner to monitor the temperature of a device: for this purpose, the switch is brought into thermal contact with the device to be protected, for example via one of its outer surfaces, so that the temperature of the protected device affects the temperature of a switching mechanism arranged inside the switch.

[0004] The switch is typically connected electrically in series with 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 DE 10 2013 109 291 the switching mechanism is arranged inside a switch housing. The switch housing is a closed housing in which the switching mechanism is sealed against the outside. The switch housing is formed in two parts. The two parts comprise a lower part which is closed by a cover part. The cover part is fixed to the lower part. For this purpose the lower part is provided with a raised, circumferential edge and the free upper edge of the lower part is bent or flanged onto the cover part.

[0006] The temperature dependent switching mechanism arranged in the switch housing comprises a spring element with a fixed movable contact and a bimetallic element interacting with the movable contact, the spring element pressing the movable contact against a fixed opposing contact arranged inside the switch housing on the cover part, the outer edge of the spring element configured as a snap-action spring disc is supported on the bottom of the switch housing, and current flows from the bottom through the snap-action spring disc and the movable contact to the fixed opposing contact and from there to the cover part.

[0007] The temperature-dependent bimetallic element, the switch of which is disclosed in DE 10 2013 109 291 and DE 10 2011 119 637 has a disk-shaped configuration and is often called a bimetallic snap-action disk, is essentially responsible for the temperature-dependent switching behavior of the switching mechanism. This bimetallic element is usually configured as a multi-layer active sheet-like device, consisting of two, three or four interconnected parts with different thermal expansion coefficients. The connection of the individual metal or metal alloy layers in this type of bimetallic element is usually a material-locking or positive-locking connection, which is achieved, for example, by rolling.

[0008] Such a bimetallic element has a first geometric configuration (cold configuration) that is stable at low temperatures below the response temperature of the bimetallic element, and a second geometric configuration (hot configuration) that is stable at high temperatures above the response temperature of the bimetallic element, and the bimetallic element snaps from its cold configuration to its hot configuration in a temperature-dependent manner in a hysteretic manner.

[0009] Thus, if the temperature of the bimetallic element rises above its response temperature as a result of a temperature increase in the device to be protected, the bimetallic element snaps from its cold configuration to its hot configuration, whereby it acts against the spring element to lift the movable contact from the fixed opposing contact, causing the switch to open and the device to be protected to be switched off and unable to heat up further.

[0010] Unless a reset lock is provided, the bimetallic element will snap back to its low temperature configuration, so that the switch is closed 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 of the device to be protected.

[0011] In its low temperature configuration, the bimetallic element is preferably mounted in the switch housing in a mechanically non-stressful manner and the bimetallic element is not used to carry 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.

[0012] In the switches disclosed in DE 10 2013 109 291 and DE 10 2011 119 637, the spring element configured as a snap-action spring disk is in permanent contact with the lower part in the region of its outer edge. In the switch disclosed in DE 10 2011 119 637, a part of the outer edge of the snap-action spring disk is connected in a material-locking manner to the lower part of the switch housing. In the switch disclosed in DE 10 2013 109 291, the snap-action spring disk rests on a circumferential shoulder provided on the lower part and is clamped between this shoulder and a spacer element configured as a spacer ring and is thereby mechanically fixed. Thus, the snap-action spring disc is permanently electrically connected to the switch housing which conducts electrical current in both the cold switching mechanism condition and the hot switching mechanism condition.

[0013] The permanent electrical connection between the snap-action spring disc and the current carrying lower part of the switch housing ensures that the contact resistance between the snap-action spring disc and the lower part of the switch housing is very low, thus eliminating a possible source of error that may occur during final continuity testing of the fully assembled temperature dependent switch. Due to manufacturing tolerances, the contact resistance between the lower part of the housing and the snap-action spring disc may be very high, with the result that the completed temperature dependent switch must be discarded as a reject.

[0014] Conversely, most switches known from the prior art are provided with a spring element on the base on the inside of the lower part of the switch housing, or on a circumferentially extending shoulder on the inside of the lower part, so that its edge is loose, i.e. can move freely. Such a switch is disclosed, for example, in DE-OS 43 45 350. It is understood that such a loosely supported spring element has a greater degree of mechanical freedom, so that it can move more freely in the switch housing when the switching mechanism snaps from the cold and hot states (and vice versa). This has a fundamentally positive effect on the service life of the switching mechanism and on the long-term consistency of its switching temperature. However, a permanent electrical connection between the spring element and the energized switch housing, which is not provided here, would result in the above-mentioned disadvantages, i.e. in particular increased rejects and increased contact resistance. Summary of the Invention [Problem to be solved by the invention]

[0015] It is therefore an object of the present invention to provide a temperature-dependent switch in which the above-mentioned disadvantages are avoided or at least reduced as far as possible in a constructively simple manner. In this respect, it is an object to provide a switch which is particularly composed of as few components as possible, is easy to install and whose service life and / or switching capacity can be increased compared to currently known temperature-dependent switches. [Means for solving the problem]

[0016] According to the invention, this object is solved by a temperature-dependent switch as claimed in claim 1, which comprises the following devices: a switch housing having a lower portion and a cover portion for closing the lower portion; a temperature dependent switching mechanism disposed within a switch housing, the switching mechanism comprising a movable contact and a bimetallic element and a spring element interacting with the movable contact, the switching mechanism configured to switch between a cold state and a hot state, the cold state pressing the movable contact against a contact surface disposed within the switch housing to establish an electrical connection between a first electrical terminal of the switch and a second electrical terminal of the switch, and the hot state moving the movable contact away from the contact surface to interrupt an electrical connection between the first electrical terminal and the second electrical terminal; a spacer element disposed inside the switch housing between the lower portion and the cover portion; At least a portion of the spring element is disposed between the spacer element and the switch housing and is secured in place by interaction of the spacer element with the switch housing; At least a portion of the bimetal element is disposed between the spring element and the spacer element and is supported on the spacer element in a hot state of the switching mechanism.

[0017] Similar to the switch disclosed in DE 10 2013 109 291, the spring element of the temperature-dependent switching mechanism in the switch according to the invention is also fixed in its position by a spacer element arranged inside the switch housing. More precisely, the spring element is fixed in its position by the interaction of the spacer element with the switch housing. This means that both the spacer element and the switch housing contribute to fixing the position of the spring element. Both the spacer element and the switch housing exert a force on the spring element, fixing it in position. There can be, but does not necessarily have to be, a direct contact between the spacer element and the spring element on the one hand and the switch housing and the spring element on the other hand. The switch housing and the spacer element can also be indirectly connected to the spring element.

[0018] However, unlike the switch disclosed in DE 10 2013 109 291, the spacer element in the switch according to the invention performs several functions simultaneously: it performs two already known functions, namely it is configured to hold the lower part and the cover part apart from each other and it is configured to fix the spring element in its position. According to the invention, the spring element additionally performs a third function, namely it serves as an abutment which can support the bimetallic element in the hot state of the switching mechanism.

[0019] Thus, several functions can be simultaneously performed by a single component in the form of a spacer element, which not only simplifies the construction of the switch, but also its assembly. The latter additional function of the switch as an abutment for the bimetallic element also has a positive effect on the service life of the switch.

[0020] In the above mentioned switches, the bimetallic element in its hot state is usually supported either on the spring element itself or on the cover part of the switch housing. Supporting the bimetallic element on the spring element has the disadvantage that it is subject to high mechanical stresses and can be damaged, especially after many switching cycles. In contrast, support on the cover part of the switch housing is less problematic, but on the one hand the switching mechanism must be adapted very precisely to the manufacturing tolerances of the components of the housing and on the other hand the bimetallic element in the hot configuration usually has to bend very strongly until its outer edge reaches the cover part and its central part presses down on the mobile contact.

[0021] However, by using abutments on the spacer element, the manufacturing tolerances of the switching mechanism are largely independent of the manufacturing tolerances of the switch housing. Furthermore, the spacer element can be arranged very close to the bimetallic element spring element, so that the bimetallic element only has to bend slightly. Mechanical wear of the spacer element is also harmless, since the spacer element can be constructed to be much more stable than, for example, the spring element.

[0022] The above-mentioned advantages resulting from a permanent electrical connection between the spring element and the current-carrying switch housing can also be realized by means of a spacer element in the switch according to the invention.

[0023] In this way, the above objective is completely achieved.

[0024] In the hot state of the switching mechanism the spring element is supported on the spacer element, but in the cold state of the switching mechanism the spring element is preferably spaced apart from the spacer element so that the spring element does not contact the spacer element in the cold state of the switch.

[0025] In a refinement, at least a portion of the spring element disposed between the spacer element and the switch housing and secured in place by interaction of the spacer element with the switch housing includes an outer edge of the spring element.

[0026] In other words, the spring element is preferably fixed in its edge position by interaction of the spacer element with the switch housing. Particularly preferably, at least a part of the spring element comprises its radially outer edge. This has the advantage of a space-saving edge mounting of the spring element, while the switching mechanism has free access to the central region of the spring element.

[0027] In a further refinement, at least a portion of the bimetallic element arranged between the spring element and the spacer element and supported on the spacer element in the hot state of the switching mechanism comprises an outer edge of the bimetallic element.

[0028] In other words, in the hot state of the switching mechanism, the outer edge of the bimetal element abuts against the spacer element. In the cold state of the switching mechanism, this outer edge is preferably spaced apart from the spacer element. This allows the switching mechanism to be arranged in as space-saving a manner as possible. Furthermore, the spacer element may be arranged at the radially outer edge of the switching mechanism in order to save space without interfering with other components of the switching mechanism.

[0029] In a further refinement, at least a portion of the spring element disposed between the spacer element and the switch housing is (i) clamped directly or indirectly between the spacer element and the lower portion, or (ii) clamped directly or indirectly between the spacer element and the cover portion.

[0030] Such a clamped arrangement between the spacer element and the lower part or between the spacer element and the cover part is particularly easy to realize the positional fixation of the spring element. In this way, the spring element can simply be inserted in the desired position inside the switch housing during assembly of the switch, the spacer element can be placed on the upper or lower side, and the switch housing can then be closed by fixing the cover part to the lower part or vice versa. Then, as soon as the cover part is fixed to the lower part, the position of the spring element is automatically fixed. This does not require any additional effort in the assembly process.

[0031] By "indirectly clamped" is meant that the spring element is clamped by the spacer element and the lower part or the spacer element and the cover part, but does not necessarily have to be in direct contact with the two components. Furthermore, a housing component or element can be placed between the two components. In particular, for example, an insulating foil or other intermediate layer can be placed between the aforementioned components.

[0032] In a further refinement, the spacer element comprises a spacer ring.

[0033] The spacer element is preferably configured as a spacer ring. Thus, the spacer element can be configured as a standard device. No additional costs, or only little, if any, are incurred by providing the spacer element. The spacer element itself can be made of a conductive material (e.g. metal) or a non-conductive material (e.g. plastic).

[0034] In a further refinement, the spacer element has a substantially L-shaped cross section.

[0035] With respect to "substantially L-shaped cross-section," the term means that the cross-sectional area of ​​the spacer element includes a shape that is at least similar to the shape of an L. Preferably, the shape of the cross-sectional area corresponds to an L-shape.

[0036] In a further refinement, a first side of the spring element facing the bimetal element faces the contact surface.

[0037] In this way, the bimetallic element is arranged on the same side of the spring element as the contact surface of the fixed opposing contact is arranged. If the contact surface of the fixed opposing contact is arranged above the spring element, the bimetallic element is also arranged above the spring element. On the other hand, if the contact surface of the fixed opposing contact is arranged below the spring element, the bimetallic element is also arranged below the spring element. This has the advantage that the bimetallic element and the spring element can be curved in the same direction both in the cold state of the switching mechanism and in the hot state of the switching mechanism. In the hot state of the switching mechanism, the centre of the bimetallic element is for example pressed directly against the central region of the spring element, and the mobile contact is lifted off the contact surface of the fixed opposing contact.

[0038] In a further refinement, the spacer element protrudes in a first direction from a first side of the spring element and comprises a support surface against which at least a portion of the bimetal element is supported in a hot state of the switching mechanism, the support surface being oriented transversely, preferably perpendicularly, to the first direction.

[0039] In this case, the term "transverse" does not necessarily mean orthogonal or perpendicular. Instead, it is understood to mean any type of orientation that is not parallel. Thus, oblique orientations at angles not equal to 0° also fall under the term "transverse."

[0040] Preferably, in the cold state of the switching mechanism, at least a portion of the bimetallic element is spaced from the support surface.

[0041] From what has been described, the cross-sectional shape of the spacer element is essentially L-shaped, and therefore it very simply functions as a kind of retaining claw that can bear on the edge of the bimetal element in the hot state of the switching mechanism, and at the same time the spacer element is preferably housed flat on the spring element and serves as a retaining device for the spring element, by which the latter is fixed in place in the switch housing.

[0042] In a further refinement, the spacer element is clamped in the switch housing by interaction of the lower part and the cover part.

[0043] This has the advantage that the spacer element is automatically fixed in its position after the switch housing is closed. This also automatically fixes at least a part of the spring element in its position after the switch housing is closed. The spacer element can be clamped directly or indirectly between the lower part and the cover part. If both the lower part and the cover part and the spacer element are made of a conductive material, an insulating element, preferably in the form of an insulating foil, is arranged at least between the spacer element and the lower part or between the spacer element and the cover part.

[0044] In a further refinement, the spring element comprises at least one compensation portion between the outer edge and the inner region, which compensation portion is configured to be radially elastic and allows mechanical deformation of the spring element.

[0045] The at least one compensation part has the advantage of compensating for or at least reducing internal deformations that may occur due to edge clamping of the spring element when the switching mechanism shifts, which, without the compensation part, would lead to mechanical stresses and ageing of the spring element and would limit the service life of the equipped switch.

[0046] Such a "compensating portion" is in this case understood to be a region of the spring element which is configured to be radially flexible or flexible and allows a radial escape or expansion movement within the spring element, whereas the outer edge of the spring element is rigidly fixed and therefore cannot move radially, or at least can only move very little. The compensating portion can therefore also be referred to as an expansion structure.

[0047] In a further refinement, the movable contact part is fixed to the spring element in a material-locking manner.

[0048] For example, the movable contact is soldered or welded to the spring element, which allows for a simple and inexpensive assembly of the switching mechanism, since the contact cannot slip during assembly. It is preferred that the movable contact is located in the center, intermediate area of ​​the spring element.

[0049] In a further refinement, the bimetallic element is held in a restrained state with play on the movable contact (and spring element).

[0050] This means that the switching mechanism can be assembled and temporarily stored as separate semi-finished parts, since the spring element, the bimetallic element and the movable contact form a unit, and it is also possible to check the switching mechanism separately, since the bimetallic element is fixed to the movable contact but has play, i.e. is loose according to said play, so that it can deform unhindered between a cold and a hot configuration.

[0051] In a further refinement, the bimetallic element and the spring element are each essentially disk-shaped and the movable contact is fixed in the center of the spring element. In a particularly preferred embodiment, both the spring element and the bimetallic element are each disk-shaped.

[0052] In a further refinement, the first electrical terminal of the switch is located on the outside of the cover part and the second electrical terminal of the switch is located on the outside of the lower part.

[0053] This ensures that the temperature dependent switch can be easily electrically connected.

[0054] In a further refinement, the lower part is provided with a free upper edge that is flanged or bent over onto the cover part.

[0055] This results in the simplest and most stable type of fastening between the lower part and the cover part, as is known for example from DE 10 2013 109 291 A1.

[0056] It is to be understood that the features mentioned above and those to be described below can be used not only in the combinations indicated in each case, but also in other combinations or alone, without departing from the scope of the invention. [Brief description of the drawings]

[0057] Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. [Figure 1] 1 is a schematic cross-sectional view of a temperature dependent switch according to a first embodiment, the switch being in its cold state; [Diagram 2] 2 is a schematic cross-sectional view of the temperature dependent switch shown in FIG. 1, the switch being in its hot state; [Diagram 3] FIG. 2 is a schematic cross-sectional view of a temperature dependent switch according to a second embodiment, the switch being in its cold state; [Figure 4] 4 is a schematic cross-sectional view of a temperature dependent switch according to a third embodiment, the switch being in its cold state; FIG. [Diagram 5] FIG. 13 is a schematic cross-sectional view of a temperature dependent switch according to a fourth embodiment, the switch being in its cold state; [Figure 6] FIG. 13 is a schematic cross-sectional view of a temperature dependent switch according to a fifth embodiment, the switch being in its cold state; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0058] 1 to 6 show five different embodiments of a switch according to the invention, each shown in schematic cross-section. In each case the switch is designated in its entirety by the numeral 10.

[0059] The switch 10 is constructed with rotational symmetry and has a circular shape when viewed from above. The switch 10 comprises a switch housing 12 in which a temperature-dependent switching mechanism 14 is arranged. The switch housing 12 comprises a pot-shaped lower part 16, which is closed by a cover part 18. The lower part 16 comprises a raised edge 20 which is bent inwards or flanged in the region of its free upper end, so that the cover part 18 is clamped or fixed to the lower part 16 with an insulating foil 22 therebetween.

[0060] The lower part 16 as well as the cover part 18 are made of an electrically conductive material, preferably metal. In the embodiment shown, the lower part 16 is a deep-drawn steel housing, which provides a relatively high pressure resistance. Insulating foils 22 are arranged between the lower part 16 and the cover part 18, which serve to electrically insulate the two switch housing components 16, 18.

[0061] The cover part 18 completely closes the lower part 16. In addition to electrical insulation, the insulating foil 22 also ensures a sufficient mechanical seal between the lower part 16 and the cover part 18, so that the interior of the switch housing 12 is sealed from the outside. This prevents the ingress of liquids and impurities from the outside into the interior of the housing.

[0062] The switching mechanism 14, disposed inside the switch housing, includes a temperature independent spring element 24 and a temperature dependent bimetallic element 26. The spring element 24 is preferably configured as a circular, disk-shaped snap-action spring disc.

[0063] The temperature-dependent bimetallic element 26 is preferably configured as a bimetallic disc, which comprises two temperature-dependent configurations: a geometric cold configuration (see FIG. 1) and a geometric hot configuration (see FIG. 2). In the region of the center 28 of the spring element 24, a contact 30 is fixed to the spring element 24. This contact 30 is connected to the spring element 24 in a material-locking manner. For example, the contact 30 is welded or soldered to the spring element 24. Since the contact 30 moves together with the spring element 24 relative to the switch housing 12 during the switching operation, the contact 30 is also called "movable contact".

[0064] The bimetallic element 26 is held with play on the movable contact 30 in a restrictive manner. The through hole 32 in the center of the bimetallic element 26 has an inner diameter slightly larger than the outer diameter of the movable contact 30 in its lower region. However, the outer diameter of the movable contact 30 in its upper region is larger than the inner diameter of the through hole 32, and the spring element 24 is arranged below the bimetallic element 26 and is rigidly connected to the movable contact 30, so that the bimetallic element 26 cannot unintentionally detach from the switching mechanism 14 despite its freedom of movement. The spring element 24, the bimetallic element 26 and the movable contact 30 thus illustrate a restrictive unit of the switching mechanism 14, which can be prefabricated as a semi-finished product and inserted as a whole into the switch housing 12 during assembly of the switch 10.

[0065] In the cold state of the switching mechanism 14 shown in Figure 1, the spring element 24 presses the moveable contact portion 30 against a contact surface 34 located on the underside of a fixed contact portion 36. In the embodiment shown in Figure 1, the fixed contact portion 36 is located on a bottom side 38 of the cover portion 18 opposite the lower portion 16.

[0066] In the region of the radially outer edge 40 of the spring element 24, the spring element 24 is fixed in the switch housing 12. More precisely, a radially outer portion 42 forming the outer edge 40 of the spring element 24 is clamped between a spacer element 44 and the lower part 16 of the switch housing 12 in the embodiment shown in FIG. 1 . The spacer element 44 is itself also clamped between the lower part 16 and the cover part 18 in the switch housing 12. The spacer element 44 is indirectly clamped between the lower part 16 and the cover part 18 and is directly located between the spring element 24 and the insulating foil 22.

[0067] When assembling the switch 10 shown in FIG. 1, the switching mechanism 14 is first inserted into the lower part 16. Next, the spacer element 44 is placed over the outer edge portion 42 of the spring element 24, and then the cover part is placed over the spacer element 44 with the insulating foil 22 therebetween. Finally, the upper raised edge 20 of the lower part is bent or flanged inwardly, so that the cover part 18 is pressed from above onto the spacer element 44, which in turn is pressed onto the spring element 24, thereby fixing the spring element 24 in position within the switch housing 12. It will be appreciated that the fixing in position only affects the outer edge portion 42 of the spring element 24, but that the central region 28 of the spring element 24 together with the movable contact portion 30 are still movable within the switch housing 12.

[0068] The spacer element 44 is configured as a spacer ring having an essentially L-shaped cross section. This spacer ring 44 protrudes from a first side 48 of the spring element 24 in a first direction, which here corresponds to the vertical direction and is indicated diagrammatically in FIG. 1 by the arrow 46. This first side 48 of the spring element 24 is the (upper) side of the spring element 24 facing the bimetal element 26 and the contact surface 34.

[0069] The spacer element 44 further comprises a bearing surface 50 oriented transversely to the first direction 46 and facing the bimetal element 26 .

[0070] An outer portion 52, including an outer edge 54, of the bimetallic element 26 is disposed between the spring element 24 and the spacer element 44. More specifically, this outer portion 52 of the bimetallic element 26 is disposed between the support surface 50 and the spring element 24. This outer portion 52 allows the bimetallic element 26 to be at the high temperature of the switching mechanism 14 supported on the support surface 50 disposed on or above the spacer element 44 (see FIG. 2).

[0071] In the closed switching position of the switch 10 shown in FIG. 1, in which the switching mechanism 14 is in the cold state, the spring element 24 thus presses the movable contact 30 against the contact surface 34 arranged on the fixed contact 36. The spring element 24 with its outer edge portion 42 is in permanent electrical contact with the lower portion 16, so that the switching mechanism 14 establishes an electrically conductive connection between the first terminal 56 and the second terminal 58 in the cold state shown in FIG. 1. The first terminal 56 is, for example, the outer side of the cover part 18. If the cover part 18 is not entirely made of metal, only a part of it can be made of metal or of a conductive material, which part is connected to the fixed contact 36 and led to the outside. For example, a shoot-through contact can be arranged on the cover part 18 above the fixed contact 36, as is known, for example, from German Patent 103 01 803. In the switch 10 shown in FIG. 1, the outer side of the lower portion 16 preferably serves as the second terminal 58.

[0072] In the cold state of switch 10, current thus flows from first terminal 56, through cover portion 18, to fixed contact portion 36, from there through movable contact portion 30, spring element 24, to lower portion 16, and finally to second terminal 58 (or vice versa). In this cold state of switch 10, bimetallic element 26 is retracted in a more or less unstressed state.

[0073] Starting from the situation shown in Fig. 1, if the temperature of the device to be monitored by the switch 10, and thus the temperature of the switch 10 and the switching mechanism 14 used therein, rises above the response temperature of the bimetallic element 26, the bimetallic element 26 snaps (changes suddenly) from its cold configuration shown in Fig. 1 to its hot configuration shown in Fig. 2. The upper side of the bimetallic element 26 thereby snaps from a convex curvature to a concave curvature. The bimetallic element 26 is then supported from below with its outer edge portion 52 resting on the support surface 50 of the spacer element 44. At the same time, the bimetallic element 26 presses the movable contact portion 30 downwards at its center, lifting the contact portion 30 from the contact surface 34. During this switching movement, the bimetallic element 26 exerts a force that acts against the force exerted by the spring element 24 on the contact portion 30 in the cold state. As a result, the spring element 24 also snaps from its upper first convex shape shown in Fig. 1 to its upper concave shape shown in Fig. 2.

[0074] This interrupts the current flow through switch 10. The switch is therefore open.

[0075] In order to give the spring element 24 the possibility of mechanical expansion when it snaps over from the situation shown in figure 1 to the situation shown in figure 2, despite its edge clamping, the spring element 24 preferably has several compensation parts 60. These compensation parts 60 allow the spring element 24 to expand and compress in the radial direction and in particular prevent internal tensions or deformations of the spring element 24. The compensation parts 60 can have a configuration similar to that disclosed in DE 10 2013 109 291 A1.

[0076] A further advantage of having the outer edge 40 of the spring element 24 fixedly clamped is that the permanent mechanical and electrical connection between the spring element 24 and the switch housing 12 means that no sparks or arcing can occur during switching operations, as is common with switching mechanisms in which the edge of the spring element lifts from the switch housing during switching operations, thereby effectively preventing contacts from burning out.

[0077] 3 shows in schematic cross-section a second embodiment of the switch 10. Here, the cold state of the switch 10 is again shown, with the switching mechanism 14 establishing a conductive connection between the first terminal 56 and the second terminal 58. The switching mechanism 14 has a similar basic configuration to the first embodiment. However, the switching mechanism is inserted into the switch housing 12 rotated 180 degrees, so-called "upside down".

[0078] The spring element 24 is arranged with its edge 42 clamped between the cover part 18 and the spacer element 44. The spacer element 44 is again arranged clamped between the lower part 16 and the cover part 18 in the switch housing 12, where, according to this second embodiment, the spacer element 44 is clamped between the spring element 24 and the lower part 16 with the insulating foil 22 interposed therebetween.

[0079] The spacer element 44 again has a substantially L-shaped cross section and is provided with a support surface 50 against which the bimetal element 26 in a high-temperature configuration can be supported at its outer edge portion 52. The first side 48 of the spring element 24 also faces both the bimetal element 26 and the contact surface 34. However, the first side 48 of the spring element 24 now faces downwards. However, according to the present embodiment, the fixed contact part 36, on which the contact surface 34 is arranged, is no longer arranged on the cover part 18 but now on the lower part 16.

[0080] However, the general switching behavior of the switching mechanism 14 remains unchanged, which is why, for the sake of simplicity, the hot state of the switch 10 is not shown again in the second embodiment shown in Figure 3.

[0081] FIG. 4 shows a third embodiment of a switch 10 according to the invention, which here is constructed essentially similarly to the first embodiment shown in FIGS. 1 and 2. The spring element 24 is again clamped with its outer edge portion 42 between the spacer element 44 and the lower part 16 of the switch housing 12. However, the switching mechanism 14 is constructed somewhat differently. Here, the first side 48 of the spring element 24 faces the bimetallic element 26 as well as the contact surface 34. However, here the bimetallic element 26 rests on a circumferential collar 62 provided on the movable contact part 30. The spring element 24 abuts against this collar 62 from the opposite underside. The movable contact part 30 is not necessarily connected to the spring element 24 in a material-locking manner. Instead, the spring element 24 here has a central through-opening 64 into which the part of the movable contact part 30 lying under the collar 62 is inserted so as to be positively locked.

[0082] A further difference with respect to the first embodiment shown in Figures 1 and 2 is that the fixed contacts 36 are not arranged on the bottom side 38 of the cover part 18. Instead, in the third embodiment shown in Figure 4, a contact carrier element 66 is arranged in the switch housing 12, to which the fixed contacts 36 are fixed. The contact carrier element 66 acts as a kind of sub-cover, which is clamped between the lower part 16 and the cover part 18. More precisely, an edge 68 of this contact carrier element 66 is clamped between the cover part 18 and the spacer element 44, with the insulating foil 22 interposed therebetween.

[0083] The contact carrier element 66 is preferably made of an electrically conductive material, for example metal, and particularly preferably has a wall thickness which is smaller than the cover part 18 of the switch housing 12 arranged above it.

[0084] The main advantage of the additional contact carrier element 66 provided here is that it can be used in a simple design manner to compensate for manufacturing tolerances on the switch housing 12 and the switching mechanism 14. Depending on the customer's requirements, the contact carrier element 66 configured as a sub-cover can be pre-formed in such a way that the desired contact pressure is achieved in the cold state of the switching mechanism 14. For example, if a high level of performance is required for the switch 10 and a high contact pressure is desired between the fixed contact 36 and the movable contact 30, a differently shaped contact carrier element 66 can be inserted into the switch housing 12 than when a lower level of performance is required for the switch. In other words, the contact carrier element 66 allows the contact pressure between the switching mechanism 14 and the fixed contact 36 to be adjusted very easily, without the switch housing 12 itself having to be modified for this purpose. It is understood that the setting of the respective contact pressure automatically results in a corresponding setting of the contact resistance between the switching mechanism 14 and the fixed contact 36. The fact that this setting can be determined more or less solely by the shape of the contact carrier element 66 provides significant cost advantages, since the switch can be adapted to a wide range of technical specifications without the need to change anything on the switching mechanism 14 or switch housing 12.

[0085] The fourth embodiment of the switch 10 according to the invention shown in Figure 5 also follows this principle. In contrast to the embodiment shown in Figure 4, here only the contact surface 34 is arranged directly on the bottom side of the contact carrier element 66. The extra fixed contact 36 is omitted.

[0086] The fifth embodiment, shown in Fig. 6, also follows the above-mentioned principle. Here, however, the contact carrier element 66 is configured as a second spring element 70, and the contact part 36 is fixed with its contact surface 34 arranged thereon. This second spring element 70 allows for an even higher contact pressure between the movable contact part 30 and the contact surface 34, and thus an even lower contact resistance between these two devices. The second spring element 70 exerts a force on the contact part 36 opposite to the force exerted by the first spring element 24 on the movable contact part 30.

[0087] Finally, it should be mentioned, with regard to the embodiment shown in Figures 4 to 6, that the second terminal 58 of the switch is designed here slightly differently than in the embodiment shown in Figures 1 to 3. This is because the terminal 58 is designed here as a recess in the lower part 16, into which a circumferential connecting ring 72 can be inserted, which is preferably welded to the lower part 16. This connecting ring 58 not only serves as an electrical connection, but can also be connected to a conveyor belt during the manufacture of the switch 10.

Claims

1. A temperature dependent switch (10), comprising: a switch housing (12) having a lower portion (16) and a cover portion (18) that closes the lower portion (16); a temperature dependent switching mechanism (14) disposed within a switch housing (12) and including a movable contact (30), and a bimetallic element (26) and a spring element (24) interacting with the movable contact (30), the switching mechanism (14) being configured to switch between a cold state and a hot state, the cold state pressing the movable contact (30) against a contact surface (34) disposed within the switch housing (12) to establish an electrical connection between a first electrical terminal (56) of the switch (10) and a second electrical terminal (58) of the switch (10), and the hot state moving the movable contact (30) away from the contact surface (34) to interrupt the electrical connection between the first electrical terminal (56) and the second electrical terminal (58); a spacer element (44) disposed inside the switch housing (12) between the lower portion (16) and the cover portion (18); At least a portion (42) of the spring element (24) is disposed between the spacer element (44) and the switch housing (12) and is fixed in place by interaction of the spacer element (44) with the switch housing (12); at least a portion (52) of the bimetal element (26) is disposed between the spring element (24) and the spacer element (44) and is supported on the spacer element (44) in a high temperature state of the switching mechanism (14).

2. 2. The temperature dependent switch of claim 1, wherein at least a portion (42) of the spring element (24) disposed between the spacer element (44) and the switch housing (12) includes an outer edge (40) of the spring element (24).

3. 2. The temperature dependent switch of claim 1, wherein at least a portion (52) of the bimetallic element (26) disposed between the spring element (24) and the spacer element (44) includes an outer edge (54) of the bimetallic element (26).

4. 2. The temperature dependent switch of claim 1, wherein at least a portion (42) of the spring element (24) disposed between the spacer element (44) and the switch housing (12) is (i) indirectly or directly clamped between the spacer element (44) and the lower portion (16), or (ii) indirectly or directly clamped between the spacer element (44) and the cover portion (18).

5. The temperature dependent switch of claim 1 , wherein the spacer element (44) comprises a spacer ring.

6. 2. The temperature dependent switch of claim 1, wherein said spacer element (44) has an L-shaped cross-section.

7. 2. The temperature dependent switch of claim 1, wherein a first side (48) of said spring element (24) opposite said bimetallic element (26) faces said contact surface (34).

8. 8. The temperature dependent switch of claim 7, wherein the spacer element (44) projects in a first direction (46) from a first side (48) of the spring element (24) and comprises a support surface (50) against which at least a portion (52) of the bimetal element (26) supports in a hot condition of the switching mechanism (14), the support surface (50) being oriented transverse to the first direction (46).

9. 2. The temperature dependent switch of claim 1, wherein the spacer element (44) is clamped within the switch housing (12) by interaction of the lower portion (16) and the cover portion (18).

10. 2. The temperature dependent switch of claim 1, wherein the spring element (24) comprises at least one compensation portion (60) between the outer edge (54) and the inner region (28), the compensation portion being configured to be radially elastic and allowing mechanical deformation of the spring element (24).

11. 2. The temperature dependent switch of claim 1, wherein the movable contact portion (30) is secured to the spring element (24) in a material-locking manner.

12. 2. The temperature dependent switch of claim 1, wherein the bimetallic element (26) is held with play but restraint on the movable contact (30).

13. 2. The temperature dependent switch of claim 1, wherein said bimetallic element (26) and said spring element (24) are each substantially disk-shaped, and said movable contact portion (30) is centrally mounted on said spring element (24).

14. 2. The temperature dependent switch of claim 1, wherein the first electrical terminal (56) is disposed on an exterior side of the cover portion (18) and the second electrical terminal (58) is disposed on an exterior side of the lower portion (16).

15. 2. The temperature dependent switch of claim 1, wherein said lower portion (16) includes a free upper edge (20) that is flanged or bent over said cover portion (18).

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