TEMPERATURE-DEPENDENT SWITCHING MECHANISM AND TEMPERATURE-DEPENDENT SWITCH

Abstract

A temperature-dependent switching mechanism for a temperature-dependent switch, comprising an electrically conductive contact member; a contact ring arranged around the contact member and movably mounted on the contact member; and a temperature-dependent bimetallic snap-action disc comprising a first through hole through which the contact member is passed, wherein the bimetallic snap-action disc is arranged on a first side of the contact ring and is movably mounted on the contact member.

Claims

1. A temperature-dependent switching mechanism for a temperature-dependent switch, comprising: an electrically conductive contact member; a contact ring arranged around and movably mounted on the electrically conductive contact member; and a bimetallic snap-action disc comprising a first through hole through which the electrically conductive contact member is passed, wherein the bimetallic snap-action disc is arranged on a first side of the contact ring and is movably mounted on the electrically conductive contact member.

2. The temperature-dependent switching mechanism according to claim 1, wherein the bimetallic snap-action disc comprises an inner section surrounding the first through hole, wherein the inner section bears against the contact ring.

3. The temperature-dependent switching mechanism according to claim 1, wherein the bimetallic snap-action disc is configured to switch in a temperature-dependent manner between a geometric low-temperature configuration and a geometric high-temperature configuration, and wherein the contact ring is configured to move relative to the electrically conductive contact member when the bimetallic snap-action disc switches from its low-temperature configuration to its high-temperature configuration.

4. The temperature-dependent switching mechanism according to claim 1, wherein the electrically conductive contact member comprises a bearing section extending along a longitudinal axis and having a first diameter, a head section arranged at a first end of the bearing section and having a second diameter larger than the first diameter, and a foot section arranged at a second end of the bearing section opposite the first end and having a third diameter larger than the first diameter, and wherein the contact ring and the bimetallic snap-action disc are mounted on the bearing section so as to be movable along the longitudinal axis between the head section and the foot section.

5. The temperature-dependent switching mechanism according to claim 4, wherein the bearing section is cylindrical.

6. The temperature-dependent switching mechanism according to claim 4, wherein an inner diameter of the contact ring is larger than the first diameter, so that there is an annular gap between the contact ring and the bearing section of the electrically conductive contact member.

7. The temperature-dependent switching mechanism according to claim 4, wherein a diameter of the first through hole is larger than the first diameter, so that there is an annular gap between the bimetallic snap-action disc and the bearing section of the electrically conductive contact member.

8. The temperature-dependent switching mechanism according to claim 4, wherein an outer diameter of the contact ring is smaller than the second diameter.

9. The temperature-dependent switching mechanism according to claim 4, wherein the second diameter is at least 50% larger than the first diameter.

10. The temperature-dependent switching mechanism according to claim 4, wherein the bearing section is integrally formed in one piece with the head section and the foot section.

11. The temperature-dependent switching mechanism according to claim 1, further comprising a temperature-independent snap-action spring disc comprising a second through hole through which the electrically conductive contact member is passed, wherein the snap-action spring disc is arranged on a second side of the contact ring opposite the first side and is movably mounted on the electrically conductive contact member.

12. The temperature-dependent switching mechanism according to claim 11, wherein the first through hole is arranged centrally in the bimetallic snap-action disc, and wherein the second through hole is arranged centrally in the snap-action spring disc.

13. The temperature-dependent switching mechanism according to claim 11, wherein the bimetallic snap-action disc and the snap-action spring disc are each circular disc-shaped.

14. A temperature-dependent switch, comprising: a temperature-dependent switching mechanism; and a switch housing surrounding the switching mechanism and having a first electrical terminal and a second electrical terminal; wherein the temperature-dependent switching mechanism comprises: an electrically conductive contact member; a contact ring arranged around and movably mounted on the electrically conductive contact member; and a bimetallic snap-action disc comprising a first through hole through which the electrically conductive contact member is passed, wherein the bimetallic snap-action disc is arranged on a first side of the contact ring and is movably mounted on the electrically conductive contact member; wherein the temperature-dependent switching mechanism is configured to establish an electrical connection between the first and the second electrical terminal below a response temperature of the bimetallic snap-action disc and to interrupt the electrical connection upon exceeding the response temperature.

15. The temperature-dependent switch according to claim 14, wherein the switching mechanism is configured to press the electrically conductive contact member below the response temperature of the bimetallic snap-action disc directly against a stationary mating contact electrically connected to the first electrical terminal and arranged inside the switch housing in order to establish the electrical connection.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0060] FIG. 1 shows a schematic sectional view of a temperature-dependent switching mechanism according to a first embodiment;

[0061] FIG. 2 shows a schematic sectional view of a temperature-dependent switch having the switching mechanism shown in FIG. 1, wherein the switch is in its low-temperature state;

[0062] FIG. 3 shows a schematic sectional view of the switch shown in FIG. 2, wherein the switch is in its high-temperature state;

[0063] FIG. 4 shows a schematic sectional view of a temperature-dependent switching mechanism according to a second embodiment;

[0064] FIG. 5 shows a schematic sectional view of a temperature-dependent switch having the switching mechanism shown in FIG. 4, wherein the switch is in its low-temperature state; and

[0065] FIG. 6 shows a schematic sectional view of the switch shown in FIG. 5, wherein the switch is in its high-temperature state.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0066] FIG. 1 shows a schematic sectional view of a first embodiment of the switching mechanism. The switching mechanism is denoted therein in its entirety with the reference numeral 10.

[0067] The switching mechanism 10 is a temperature-dependent switching mechanism. As explained in more detail in the following, the switching mechanism 10 switches between a low-temperature state and a high-temperature state depending on the temperature.

[0068] The switching mechanism 10 has a four-component design. It comprises a contact member 12, a temperature-dependent bimetallic snap-action disc 14, a contact ring 16 and a temperature-independent snap-action spring disc 18. The bimetallic snap-action disc 14, the contact ring 16 and the snap-action spring disc 18 are held captive on the contact member 12, but are mounted so that they can move relative to it.

[0069] Since the bimetallic snap-action disc 14, the contact ring 16 and the snap-action spring disc 18 are held captive on the contact member 12, unintentional detachment of the components 14, 16, 18 from the contact member 12 is prevented. The switching mechanism 10 can thus be pre-produced as a semi-finished product and then installed as a complete unit in a corresponding switch, as shown in FIGS. 2 and 3, for example.

[0070] The two snap-action discs 14, 18 are preferably circular in shape, wherein each comprises a centrally arranged through hole 20, 22. The through hole 20 arranged centrally in the bimetallic snap-action disc 14 is referred to as the first through hole in the present case. The through hole 22 arranged centrally in the snap-action spring disc 18 is referred to as the second through hole.

[0071] The two snap-action discs 14, 18 are fitted over the contact member 12 with their respective through holes 20, 22 and rest from different sides against the contact ring 16, which is also fitted over the contact member 12. The bimetallic snap-action disc 14 bears against the top side 24 of the contact ring 16, which is herein referred to as the first side. The snap-action spring disc 18 bears against the opposite bottom side 26 of the contact ring 16, which is herein referred to as the second side of the contact ring 16. Both snap-action discs 14, 18 bear against the contact ring 16 with their respective inner sections 28, 30, i.e. in particular with the respective central region surrounding the respective through hole 20, 22.

[0072] The contact member 12 is preferably made of metal. It comprises a head section 32, a foot section 34 and a bearing section 36 arranged between the head section 32 and the foot section 34. All three sections 32, 34, 36 are integrally connected to each other, i.e. formed in one piece.

[0073] Overall, the contact member 12 is essentially mushroom-shaped in this embodiment. The head section 32 is essentially cap-shaped, the bearing section 36 is cylindrical, and the base section 34 is essentially dovetail-shaped. However, it will be understood that the three aforementioned sections 32, 34, 36 of the contact member 12 can, in principle, comprise any other shapes.

[0074] It is preferred that the diameter D2 of the head section 32 and the diameter D3 of the foot section 34 are each larger than the diameter D1 of the bearing section 36. The bearing section 36 serves to axially guide the two snap-action discs 14, 18 and the contact ring 16 along the longitudinal axis 38 of the bearing section 36. Therefore, the inner diameter D5 of the contact ring 16 is larger than the diameter D1 of the bearing section 36, so that there is an annular gap between the contact ring 16 and the bearing section 36. There is also an annular gap between the bimetallic snap-action disc 14 and the bearing section 36 and between the snap-action spring disc 18 and the bearing section 36 in order to ensure the mobility of the two snap-action discs 14, 18 relative to the contact part 12. The inner diameter D5 of the contact ring 16 can correspond to the diameter of the through hole 20 and the diameter of the through hole 22. However, the two through holes 20, 22 of the snap-action discs 14, 18 do not necessarily have to have the same diameter. Nor does the diameter of the two through holes 20, 22 necessarily have to be the same as the inner diameter D5 of the contact ring 16.

[0075] The two snap-action discs 14, 18 and the contact ring 16 are mounted movably relative to the bearing section 36 along the bearing axis 38. The head section 32 and the foot section 34, on the other hand, each form an axial end stop which limits the upwardly and downwardly movement of the three aforementioned devices 14, 16, 18 along the longitudinal axis 38.

[0076] In order to be able to ensure the greatest possible mobility of the two snap-action discs 14, 16 within the limits defined by the head section 32 and the foot section 34, the contact ring 16 is preferably configured to be significantly smaller than the head section 32. In particular, the outer diameter D4 of the contact ring 16 is smaller than the diameter D2 of the head section 32. Furthermore, it is preferred that the diameter D2 of the head section 32 is significantly larger than the diameter D1 of the bearing section 36. In particular, the following is preferred: D2?1.5 D1. A configuration of the head section 32 of the contact member 12 with a comparatively large diameter offers the advantage that the head section 32, in addition to its function as an end stop for the components 14, 16, 18, also serves as an arc shield, which shields the components 14, 16, 18 of the switching mechanism 10 from an arc that may occur on the top side of the head section 32 in the event of a switching operation.

[0077] FIGS. 2 and 3 show an embodiment of a temperature-dependent switch comprising a switching mechanism 10 according to the first embodiment shown in FIG. 1. The switch is denoted in its entirety with the reference numeral 100.

[0078] FIG. 2 shows the low-temperature state of the switch 100. FIG. 3 shows the high-temperature state of the switch 100.

[0079] The switch 100 comprises a switch housing 40, inside which the switching mechanism 10 is arranged. The switch housing 40 comprises a pot-like lower part 42 and a cover part 44, which is held on the lower part 42 by a bent or flanged upper edge 46.

[0080] In the embodiment of the switch 100 shown in FIGS. 2 and 3, both the lower part 42 and the cover part 44 are made of an electrically conductive material, preferably metal. An insulating foil 48 is arranged between the lower part 42 and the cover part 44. The insulating film 48 provides electrical insulation of the lower part 42 from the cover part 44. The insulating film 48 also provides a mechanical seal that prevents liquids or impurities from entering the interior of the housing from the outside.

[0081] Since the lower part 42 and the cover part 44 are each made of electrically conductive material in this embodiment, thermal contact to an electrical device to be protected can be established via their outer surfaces. The outer surfaces also serve as the electrical external terminals of the switch 100. For example, the outer surface 50 of the cover part 44 can function as the first electrical terminal and the outer surface 52 of the lower part 42 can function as the second electrical terminal.

[0082] Furthermore, as shown in FIGS. 2 and 3, a further insulating layer 54 can be arranged on the outside of the cover part 44.

[0083] The switching mechanism 10 is arranged clamped between the lower part 42 and the cover part 44. The contact member 12 is oriented with its head section 32 opposite a counter-contact 56 arranged on the inside 58 of the cover part 44. This counter-contact 56 is also referred to as the first stationary contact in the present case. The inside 60 of the lower part 42 serves as the second stationary contact.

[0084] In the state shown in FIG. 2, the switch 100 is in its low-temperature state, in which the temperature-independent snap-action spring disc 18 is in its first configuration and the temperature-dependent bimetallic snap-action disc 14 is in its low-temperature configuration. Thereby, the snap-action spring disc 18 presses the contact member 12 with its head section 32 against the mating contact 56. The outer, circumferential edge 62 of the snap-action spring disc 18 is supported on the inside 60 of the lower part 42.

[0085] The switch 100 is thus in its closed state, in which an electrically conductive connection is established between the first stationary contact 56 and the second stationary contact 60 via the contact member 12 and the snap-action spring disc 18. The contact pressure between the contact member 12 and the first stationary contact 56 is generated by the snap-action spring disc 18.

[0086] In this state of the switch 100, however, the bimetallic snap-action disc 14 hangs freely into the interior of the switch housing 40 with its outer, circumferential edge 64. More precisely, the snap-action spring disc 18 presses the contact ring 16 upwardly, whereby the latter also presses the bimetallic snap-action disc 14 upwardly against the head section 32 of the contact member 12. In the low-temperature state 100, the snap-action spring disc 18, the contact ring 16 and the bimetallic snap-action disc 14 are thus in their highest or uppermost position relative to the bearing section 36 of the contact member 12, viewed along the longitudinal axis 38 of the contact member. The current flows from the first electrical terminal 50 via the cover part 44, the first stationary mating contact 56 into the contact member 12 and from the contact member 12 via the bimetallic snap-action disc 14, the contact ring 16, the snap-action spring disc 18 and the second stationary contact 60 into the lower part 42 and ultimately to the second electrical terminal 52 (or vice versa).

[0087] By the contact ring 16 mounted movably on the contact member 12, manufacturing tolerances occurring on the two snap-action discs 14, 18 are usually automatically compensated, since this contact ring 16 ensures that the two snap-action discs 14, 18 are automatically pressed into the uppermost position in the low-temperature state of the switch 100, in which the bimetallic snap-action disc 14 bears against the bottom side of the head section 32 of the contact member 12. Accordingly, the manufacturing tolerances of the two snap-action discs 14, 18 need not be aligned with each other, since the switching mechanism 10 as a whole has an overall height measured along the longitudinal axis 38 which is adapted to the level of the interior of the switch housing 40, i.e. the distance between the lower part 42 and the cover part 44.

[0088] If the temperature of the device to be protected and thus the temperature of the switch 100 and the bimetallic snap-action disc 14 arranged therein now increases to the response temperature of the bimetallic snap-action disc 14 or above this response temperature, the bimetallic snap-action disc 14 snaps from its convex low-temperature configuration shown in FIG. 2 to its concave high-temperature configuration shown in FIG. 3. During this snap-action, the bimetallic snap-action disc 14 is supported with its outer edge 64 on the bottom side 58 of the cover part 44. With its center, the bimetallic snap-action disc 14 pulls the movable contact member 12 downwards and lifts the movable contact member 12 off the first stationary contact 56. As a result, the snap-action spring disc 18 simultaneously bends downwards at its center, so that the snap-action spring disc 18 snaps from its first stable geometric configuration shown in FIG. 2 to its second geometrically stable configuration shown in FIG. 3.

[0089] In the high-temperature state of the switch 100 shown in FIG. 3, the inner section 28 of the bimetallic snap-action disc 14 presses on the contact ring 16. The contact ring 16 in turn presses on the inner section 30 of the spring disc 18. In this state of the switch 100, the inner section 28 of the bimetallic snap-action disc 14, the contact ring 16 and the inner section 30 of the spring disc 18 are thus in their lowest position relative to the bearing section 36 of the contact member 12. When the two snap-action discs 14, 18 snapped from the state shown in FIG. 2 into the state shown in FIG. 3, not only is the contact member 12 as a whole displaced downwards along the longitudinal axis 38, but the inner sections 28, 30 of the two snap-action discs and the contact ring 16 are also displaced downwards along the longitudinal axis 38 relative to the contact member 12.

[0090] FIG. 3 shows the high-temperature state of the switch 100, in which the switch 100 is open. The circuit is thus interrupted.

[0091] If the device to be protected and thus the switch 100 including the bimetallic snap-action disc 14 then cools down again, the bimetallic snap-action disc 14 snaps back into its low-temperature state when the reset temperature, which is also referred to as the switch-back temperature, is reached, as shown in FIG. 2, for example. The switch 100 therefore has a temperature-dependent, reversible switching behavior.

[0092] FIG. 4 shows a second embodiment of the switching mechanism 10. Again, the switching mechanism 10 comprises a contact member 12, a bimetallic snap-action disc 14, a contact ring 16 and a snap-action spring disc 18. The bimetallic snap-action disc 14, the contact ring 16 and the snap-action spring disc 18 are also movably but captively mounted on the contact member 12 in this embodiment.

[0093] The basic structure of the switching mechanism 10 mentioned above with regard to the first embodiment shown in FIG. 1 is also realized in a similar way in the second embodiment of the switching mechanism 10 shown in FIG. 4, which is why the differences to the first embodiment are essentially emphasized in the following.

[0094] There is a fundamental difference in the shape of the contact member 12. It is true that the contact member 12 here also comprises the three different sections 32, 34, 36 which are integrally connected to one another, and the functions of these three sections 32, 34, 36 are also the same as before. However, in the second embodiment of the switching mechanism 10 shown in FIG. 4, the head section 32 of the contact member 12 in particular comprises a slightly different shape.

[0095] Instead of being cap-shaped, the head section 32 of the contact member 12 is essentially plate-shaped here. In addition, the head section 32 is even wider than in the first embodiment. The reason for this is, in particular, that in the embodiment shown in FIG. 4, as explained in the following, the contact member 12 acts as a contact plate or contact bridge, which in the low-temperature state of the switch 100 comes into direct contact with or rests against both stationary contacts 56, 60 of the switch 100.

[0096] A further difference in the first embodiment shown in FIG. 1 is that the states of the two snap-action discs 14, 18 are reversed. It is true that the two snap-action discs 14, 18 are still arranged on opposite sides of the contact ring 16. However, in the second embodiment of the switching mechanism 10 shown in FIG. 4, the bimetallic snap-action disc 14 is arranged below the contact ring 16 and the snap-action spring disc 18 is arranged above the contact ring 16.

[0097] FIGS. 5 and 6 show an embodiment of the switch 100 in which the switching mechanism 10 shown in FIG. 4 is used in accordance with the second embodiment. Again, FIG. 5 shows the low-temperature state of the switch 100 and FIG. 6 shows the high-temperature state of the switch 100. The same or equivalent components to the first embodiment of the switch 100 shown in FIGS. 2 and 3 are indicated by the same reference signs in the second embodiment of the switch 100 shown in FIGS. 5 and 6.

[0098] The switch 100 also comprises a switch housing 40 in which the temperature dependent switching mechanism 10 is arranged. The housing 40 comprises a pot-like lower part 42 and a cover part 44 closing the lower part 42. The cover part 44 is held on the lower part 42 by a bent-over upper edge 46 of the lower part 42. For reasons of clarity, the bent-over edge 46 is not illustrated extending across the lid part 44 and is bent down completely onto the lid part 44.

[0099] The lower part 42 is preferably made of an electrically conductive material, e.g. metal. In the embodiment shown in FIGS. 5 and 6, however, the cover part 44 is made of electrically insulating material, for example plastic or ceramic.

[0100] A spacer ring 66 is arranged between the cover part 44 and the lower part 42, which keeps the cover part 44 at a distance from the lower part 42.

[0101] The cover part 44 comprises a first stationary contact 56 and a second stationary contact 60 on its inner side 58. The two stationary contacts 56, 60 are each configured as a rivet which extends through the cover part 44. The outer sides of these two rivets can be used as first and second electrical terminals 50, 52 of the switch 100.

[0102] In the low-temperature state of the switch 10 shown in FIG. 5, the contact member 12 bears with the top side 68 of its head section 32 against the two stationary contacts 56, 60, so that in this switching state the contact member 12 provides an electrically conductive connection between the two stationary contacts 56, 60.

[0103] Accordingly, the contact member 12 is again made of electrically conductive material, e.g. metal. The top side 68 of the contact member 12 can be coated with an electrically conductive coating to improve conductivity.

[0104] The contact pressure with which the contact member 12 is pressed against the two stationary contacts 56, 60 in the low-temperature state of the switch 10 shown in FIG. 5 is generated by the snap-action spring disc 18. With its inner section 30, the snap-action spring disc 18 presses from below against the bottom side of the head section 32 of the contact member 12. With its outer edge 62, the snap-action spring disc 18 is thereby supported on a circumferential shoulder 70 configured in the lower part 42. The spacer ring 66 is also arranged on this shoulder 70. The circumferential edge 62 of the snap-action spring disc 18 is fixed between the shoulder 70 and the spacer ring 66.

[0105] With its inner edge area 28, the bimetallic snap-action disc 14 presses the contact ring 16 from below against the snap-action spring disc 18. Thereby, the outer, circumferential edge 64 of the bimetallic snap-action disc 14 is supported on the inner bottom of the lower part 42 of the housing 40.

[0106] If the temperature of the switch 100 and thus the temperature of the bimetallic snap-action disc 14 now increases from the low-temperature state shown in FIG. 5 to the response temperature of the bimetallic snap-action disc or above it, the bimetallic snap-action disc 14 snaps from its convex position shown in FIG. 5 to its concave position shown in FIG. 6. The outer edge 64 of the bimetallic snap-action disc 14 then rests against the snap-action spring disc 18. At the same time, the inner section 28 of the bimetallic snap-action disc 14 presses upwardly on the base section 34 of the contact member 12 and thereby pulls the contact member 12 downwardly away from the two stationary contacts 56, 60.

[0107] The snap-action spring disc 18 thereby also snaps from its first position shown in FIG. 5 to its second position shown in FIG. 6, in which it presses the contact ring 16 from upwardly onto the inner section 28 of the bimetallic snap-action disc 14 with its inner section 30.

[0108] Thus, also in this embodiment, when switching from the low-temperature state to the high-temperature state of the switch 100, there is not only a downward positional displacement of the contact member 12 along the longitudinal axis 38, but also a downward displacement of the devices 14, 16, 18 relative to the contact member 12 along the longitudinal axis 38.

[0109] It is to be understood that the foregoing is a description of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.

[0110] As used in this specification and claims, the terms for example, e.g., for instance, such as, and like, and the verbs comprising, having, including, and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.