Temperature-dependent switch

Abstract

A temperature-dependent switch having a housing with an upper part and a lower part, wherein a first and a second stationary contact are arranged on the housing, and a temperature-dependent switching mechanism having a movable contact member. In its first switching position, the switching mechanism presses the movable contact member against the first contact and thereby produces an electrically conductive connection between the two contacts via the contact member, and, in its second switching position, keeps the movable contact member spaced apart from the first contact. A closing lock prevents the switch, once having opened, from closing again by locking the switching mechanism permanently in its second switching position in a mechanical manner. The closing lock comprises a substantially disc-shaped locking element and a first latching member, which, in order to lock the switching mechanism, interacts in the second switching position with a second latching member that is arranged on the movable contact member.

Claims

1. A temperature-dependent switch, comprising: a housing having a lower part and an upper part; a first stationary contact that is arranged on the upper part of the housing; a second stationary contact that is arranged on the housing; a temperature-dependent switching mechanism that is arranged in the housing and comprises a movable contact member, wherein, in a first switching position, the switching mechanism presses the movable contact member against the first stationary contact and thereby produces an electrically conductive connection between the first stationary contact and the second stationary contact via the movable contact member, and wherein, in a second switching position, the switching mechanism keeps the movable contact member spaced apart from the first stationary contact and thereby disconnects the electrically conductive connection; and a closing lock that prevents the switch once having opened from closing again by locking the switching mechanism permanently in the second switching position in a mechanical manner, wherein the closing lock comprises a substantially disc- or plate-shaped locking element, which is arranged locally between the switching mechanism and an inner bottom surface of the lower part, the locking element being clamped in the lower part and/or connected to the lower part by means of a firmly bonded connection, and wherein the closing lock comprises a first latching member and a second latching member, the first latching member being arranged on the locking element and the second latching member being arranged on the movable contact member, wherein the first latching member and the second latching member interact with each other in the second switching position in order to lock the switching mechanism.

2. The switch according to claim 1, wherein one of the first latching member and the second latching member comprises a resilient tongue, a spring claw or a spring hook, and wherein the respective other one of the first latching member and the second latching member comprises a recess, a hole or a latching lug.

3. The switch according to claim 1, wherein the locking element is clamped between a first spacer element and a second spacer element, the first spacer element and the second spacer element being inserted into the housing.

4. The switch according to claim 3, wherein the first spacer element rests on the inner bottom surface of the lower part, and wherein the switching mechanism rests, at least in the first switching position, on the second spacer element.

5. The switch according to claim 4, wherein the first spacer element comprises as a first spacer ring, and wherein the second spacer element comprises a second spacer ring.

6. The switch according to claim 1, wherein the firmly bonded connection between the closing lock and the lower part of the housing is a welded or soldered connection.

7. The switch according to claim 1, wherein the movable contact member comprises an anchor having a latching lug that forms the second latching member, the anchor and the latching lug being arranged on a lower side of the movable contact member facing the inner bottom surface.

8. The switch according to claim 7, wherein the anchor has a frustoconical, round or tapered shape between the latching lug and a lower end of the anchor facing the inner bottom surface.

9. The switch according to claim 1, wherein the locking element has a shape of a circular disc and comprises a central hole, wherein, in the second switching position, the second latching member penetrates through the central hole and latches with the first latching member.

10. The switch according to claim 1, wherein the switching mechanism comprises a temperature-dependent bimetal snap-action disc having a geometric high-temperature configuration and a geometric low-temperature configuration, and wherein the switching mechanism comprises a spring disc on which the movable contact member is arranged.

11. The switch according to claim 10, wherein the spring disc is a bistable spring disc having two temperature-independent stable geometric configurations, wherein, in a first of the two geometric configurations, the spring disc presses the movable contact member against the first stationary contact and, in a second of the two geometric configurations, the spring disc keeps the movable contact member spaced apart from the first stationary contact.

12. The switch according to claim 11, wherein the bimetal snap-action disc, when transitioning from its low-temperature configuration into its high-temperature configuration, is supported by its edge at a part of the switch and acts on the spring disc such that the spring disc snaps from the first geometric configuration into the second geometric configuration.

13. The switch according to claim 11, wherein the spring disc is in the first geometric configuration electrically connected to the second contact via its edge.

14. The switch according to claim 10, wherein the bimetal snap-action disc and the spring disc are each fixed to the movable contact member.

15. The switch according to claim 10, wherein the first stationary contact is arranged on an inner side of the upper part of the housing, wherein the movable contact member comprises a movable contact part that interacts with the first stationary contact, and wherein the spring disc interacts with the second stationary contact.

16. The switch according to claim 1, wherein the first stationary contact and the second stationary contact are arranged on an inner side of the upper part of the housing, and wherein the movable contact member comprises a current transfer member that interacts with the first stationary contact and the second stationary contact.

17. A temperature-dependent switch, comprising: a housing having a lower part and an upper part; a first stationary contact that is arranged on the upper part of the housing; a second stationary contact that is arranged on the housing; a temperature-dependent switching mechanism that is arranged in the housing and comprises a movable contact member, wherein, in a first switching position, the switching mechanism presses the movable contact member against the first stationary contact and thereby produces an electrically conductive connection between the first stationary contact and the second stationary contact via the movable contact member, and wherein, in a second switching position, the switching mechanism keeps the movable contact member spaced apart from the first stationary contact and thereby disconnects the electrically conductive connection; and a closing lock that prevents the switch once having opened from closing again by locking the switching mechanism permanently in the second switching position in a mechanical manner, wherein the closing lock comprises a substantially disc- or plate-shaped locking element, which is arranged locally between the switching mechanism and an inner bottom surface of the lower part, the locking element being clamped in the lower part and/or connected to the lower part by means of a firmly bonded connection, and wherein the closing lock comprises a first latching member and a second latching member, the first latching member being arranged on the locking element and the second latching member being arranged on the movable contact member, wherein the first latching member and the second latching member interact with each other in the second switching position in order to lock the switching mechanism, wherein the locking element is clamped between a spacer element and the lower part of the housing.

18. The switch according to claim 17, wherein the switching mechanism rests, at least in the first switching position, on the spacer element.

19. The switch according to claim 18, wherein the spacer element comprises a spacer ring.

20. A temperature-dependent switch, comprising: a housing having a lower part and an upper part; a first stationary contact that is arranged on the upper part of the housing; a second stationary contact that is arranged on the housing; a temperature-dependent switching mechanism that is arranged in the housing and comprises a movable contact member, wherein, in a first switching position, the switching mechanism presses the movable contact member against the first stationary contact and thereby produces an electrically conductive connection between the first stationary contact and the second stationary contact via the movable contact member, and wherein, in a second switching position, the switching mechanism keeps the movable contact member spaced apart from the first stationary contact and thereby disconnects the electrically conductive connection; and a closing lock that prevents the switch once having opened from closing again by locking the switching mechanism permanently in the second switching position in a mechanical manner, wherein the closing lock comprises a substantially disc- or plate-shaped locking element, which is arranged locally between the switching mechanism and an inner bottom surface of the lower part, the locking element being clamped in the lower part and/or connected to the lower part by means of a firmly bonded connection, and wherein the closing lock comprises a first latching member and a second latching member, the first latching member being arranged on the locking element and the second latching member being arranged on the movable contact member, wherein the first latching member and the second latching member interact with each other in the second switching position in order to lock the switching mechanism, wherein the locking element comprises an annular section and at least two webs extending radially inwards from the annular section, wherein each of the at least two webs comprises a free end at which a latching element is arranged, wherein the latching elements together form the first latching member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic sectional view of a first embodiment of the switch in its low-temperature position;

(2) FIG. 2 shows a schematic sectional view of the first embodiment of the switch shown in FIG. 1 in its high-temperature position;

(3) FIG. 3 shows a schematic sectional view of a second embodiment of the switch in its low-temperature position;

(4) FIG. 4 shows a schematic sectional view of a third embodiment of the switch in its low-temperature position.

(5) FIG. 5 shows a schematic sectional view of a fourth embodiment of the switch in its low-temperature position;

(6) FIG. 6 shows a top view from above of a locking element according to a first embodiment which is used in the switch; and

(7) FIG. 7 shows a top view from above of the locking element according to a second embodiment which is used in the switch.

DESCRIPTION OF PREFERRED EMBODIMENTS

(8) FIG. 1 shows a schematic sectional view of a switch 10, which is rotationally symmetrical in top view and preferably has a circular shape.

(9) The switch 10 comprises a housing 12 in which a temperature-dependent switching mechanism 14 is arranged. The housing 12 comprises a pot-shaped lower part 16 and an upper part 18, which is held to the lower part 16 by a bent or flanged edge 20.

(10) In the first embodiment shown in FIG. 1, both the lower part 16 and the upper part 18 are made of an electrically conductive material, preferably metal. A spacer ring 22, which supports the upper part 18 with an interposed insulating foil 24 and keeps the upper part 18 at a distance from the lower part 16, is arranged between the lower part 16 and the upper part 18.

(11) The insulating foil 24 provides electrical insulation of the upper part 18 against the lower part 16. The insulating foil 24 also provides a mechanical seal that prevents liquids or impurities from entering the interior of the housing from outside.

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

(13) Another insulating foil 26 can be applied to the outside of the upper part 18, as shown in FIG. 1.

(14) The switching mechanism 14 comprises a spring disc 28 and a temperature-dependent snap-action disc 30. The spring disc 28 is preferably designed as a bistable spring disc. Thus, it has two temperature-independent stable geometric configurations. The first configuration is shown in FIG. 1. The temperature-dependent snap-action disc 30 is preferably designed as a bistable snap-action disc as well. It has two temperature dependent configurations, a geometric high-temperature configuration and a geometric low-temperature configuration. In the first switching position of the switching mechanism 14 shown in FIG. 1, the snap-action disc 30 is in its geometric low-temperature configuration.

(15) The spring disc 28 rests with its edge 32 on a circumferential shoulder 34 formed in the lower part 16 and is clamped between this shoulder 34 and the spacer ring 22. The snap-action disc 30 rests with its edge 36 on another shoulder 38, which is also formed circumferentially in the lower part 16.

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

(17) On its upper side, the movable contact member 42 comprises a movable contact part 46. The movable contact part 46 interacts with a fixed counter contact 48, which is located on an inner side of the upper part 18. This counter contact 48 is herein also referred to as the first stationary contact. The outside of the lower part 16 serves as the second stationary contact 50.

(18) In the position shown in FIG. 1, the switch 10 is in its low-temperature position, in which the spring disc 28 is in its first configuration and the snap-action disc 30 is in its low-temperature configuration. The spring disc 28 presses the movable contact part 42 against the first stationary contact 48.

(19) In the closed low-temperature position of the switch 10 according to FIG. 1, an electrically conductive connection is thus produced between the first stationary contact 48 and the second stationary contact 50 via the movable contact member 42 and the spring disc 30.

(20) If the temperature of the device to be protected, and thus the temperature of the switch 10 and the snap-action disc 30 arranged therein, the snap-action disc snaps from the low-temperature configuration shown in FIG. 1 to its concave high-temperature configuration shown in FIG. 2. When this snap-action occurs, the edge 36 of the snap-action disc 30 is supported by a part of the switch 10, in this case by the edge 32 of the spring disc 28. Thereby, the snap-action disc 30 pulls with its center 44 the movable contact part 46 downwards and lifts off the movable contact part 46 from the first stationary contact 48. This simultaneously causes the spring disc 28 to bend downwards at its center 40 so that the spring disc 28 switches from its first stable geometric configuration shown in FIG. 1 to its second stable geometric configuration shown in FIG. 2. FIG. 2 thus shows the high-temperature position of the switch 10 in which it is open. The electric circuit is thus disconnected.

(21) When the device to be protected and thus the switch 10 including the snap-action disc 30 then cool down again, the snap-action disc 30 snaps back into its low-temperature position, as shown for example in FIG. 1. In this case, the snap-action disc 30 would actually move the spring disc 28 back to its first configuration shown in FIG. 1 and thus close the switch 10 again. However, with the switch 10, this resetting process is prevented by a closing lock 52.

(22) The closing lock 52 comprises a substantially plate- or disc-shaped locking element 54, which in the first embodiment shown in FIGS. 1 and 2 is materially bonded to the inner bottom surface 56 of the lower part 16. The locking element 54 comprise a first latching member 58 which, in the high-temperature position of the switch 10 shown in FIG. 2, interacts with a second latching member 60 arranged at the movable contact member 42 to mechanically lock the switching mechanism 14.

(23) In the first embodiment of the switch 10, which is shown in FIGS. 1 and 2, the first latching member 58 comprises a plurality of spring claws 62. The second latching member 60, on the other hand, is configured as a latching lug 64, which is formed circumferentially on a type of anchor 66, which is attached to the lower side of the movable contact member 42. The anchor 66 is either attached to the contact member 42 or formed integrally with it. The anchor 66 thus forms a component of the movable contact member 42.

(24) When assembling the switch 10, the locking element 54 together with the first latching member 58 can be inserted as a separate component into the lower part 16 and then welded or soldered to the inner bottom surface 56. This fixes the locking element 54 to the lower part.

(25) As can be seen in particular from FIG. 2, the anchor 66 with its latching lug 64 latches with the spring claws 62 arranged on the locking element 54 as soon as the snap-action disc 30 snaps into its high-temperature configuration due to temperature conditions and the switch 10 is opened. A re-closing of the switch 10 is then permanently prevented because the spring claws 62 of the locking element 54 keep the anchor 66 permanently in the lower position shown in FIG. 2, regardless of whether the snap-action disc 30 snaps back into its geometric low-temperature configuration or not.

(26) In order to enable a latching between the two latching members 58, 60 that is as simple as possible, the spring claws 62 are preferably elastically resilient. As soon as the anchor 66 moves into the space between the spring claws 62 when switch 10 is opened, the spring claws are spread radially outwards and then snap back radially inwards into the latching lug 64 provided on the anchor 66 as soon as the movable contact member 42 together with the anchor 66 has moved sufficiently far down (see FIG. 2).

(27) The locking of the spring claws 62 with the latching lug 64 can be further facilitated if the lower end 63 of the movable contact member 42 or of the anchor 66 is round, tapered or frustoconical, since, upon opening of the switch 10, the anchor 66 can then be moved past the spring claws 62 without much resistance until they latch with the latching lug 64.

(28) Except for the first latching member 58 or the spring claws 62, the locking element 54 can have a shape of a plate or disc. In the first embodiment shown in FIGS. 1 and 2, however, it is advantageous if the locking element 54 is only substantially plate- or disc-shaped having a plurality of recesses, as shown schematically in FIG. 6.

(29) In the embodiment shown in FIG. 6, the locking element 54 comprises an annular section 68, from which three webs 70 extend radially inward. A spring claw 62 is arranged at each end of the webs 70 as a latching element. The three spring claws 62 act as a kind of tripod that interacts in the open state of the switch 10 with the latching lug 64 formed on the anchor 66. This results in a mechanically determined latching connection.

(30) FIG. 3 shows a second embodiment of the switch 10, in which the housing 12 and the switching mechanism 14 are basically of the same construction as in the first embodiment shown in FIGS. 1 and 2. The closing lock 52 is also basically the same as in the first embodiment. However, according to the second embodiment, the locking element 54 is not firmly bonded to the inner bottom surface 56, but is instead arranged clamped in the lower part 16.

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

(32) The substantially disc-shaped locking element 54 is thus clamped between the spacer element 72 and the inner bottom surface 56 of the lower part 16. Since a firmly bonded connection of the locking element 54 with the lower part 16 is not required here, this embodiment of the switch 10 can be manufactured even more easily than embodiment of the switch 10 shown in FIGS. 1 and 2.

(33) The spacer element 72 also offers the advantage that the position of the switching mechanism 14 can be adjusted depending on the height of the spacer element 72. In this example, the snap-action disc 30 rests with its edge 36 on the spacer element 72.

(34) The spacer element 72 is preferably made of electrically insulating material. At least the ohmic resistance of the spacer element 72 can be adjusted in such a way that it prevents current from flowing through the snap-action disc 30 resting on the spacer element 72, when the switch is closed. This prolongs the service life of the snap-action disc 30.

(35) The use of the spacer element 72 offers the further advantage that the shoulder 38, which would otherwise have to be provided, can be omitted (see FIGS. 1 and 2). The lower part 16 can therefore be produced much more easily. It can, for example, be produced as a punched part.

(36) FIG. 4 schematically shows a third embodiment of the switch 10. Therein, the housing 12 of the switch 10 is basically the same or at least similar to the first two embodiments shown in FIGS. 1-3. However, the layout of the switching mechanism 14′ and the layout of the closing lock 52′ differentiate the switch 10 according to the third embodiment from the first two examples.

(37) The movable contact member 42′ additionally comprises a ring 74 surrounding the contact member 42′. This ring 74 is preferably pressed onto the contact member 42′.

(38) The ring 74 comprises a circumferential shoulder 76 on which the snap-action disc 30 rests with its center 44. The spring disc 28 is clamped between the ring 74 and the upper widened section of the contact member 42′. In this way, the temperature-dependent switching mechanism 14′ shown in FIG. 4 is a captive unit consisting of contact element 42′, spring disc 28 and snap-action disc 30 just like the switching mechanism 14 shown in FIGS. 1-3.

(39) In the region of the lower end of the contact element 42′, the second latching member 60′ is arranged. This can be designed in one piece with the contact element 42′, directly attached to the contact element 42′ or attached to the ring 74.

(40) The second latching member 60′ here preferably comprises one or more resilient tongues 78. These resilient tongues 78 interact with the first latching member 58′ of the locking element 54′ in the sense of the closing lock 52′ when the switch is open.

(41) In this case, the locking element 54′ is configured as a circular disc with a central hole 80. The locking element 54′ is exemplarily shown in FIG. 7 in a top view from above.

(42) In this embodiment, the hole 80 or the inner edge 82 of the locking element 54′ surrounding the hole 80 acts as a second latching member 60 that interacts with the resilient tongues 78 to realize the closing lock 52′.

(43) In the embodiment shown in FIG. 4, the disc-shaped locking element 54′ is arranged, as before, between the switching mechanism 14′ and the inner bottom surface 56 of the lower part 16. However, it does not rest directly on the inner bottom surface 56. Instead, the locking element 54′ in FIG. 4 is clamped between two spacer elements 84, 86.

(44) The first spacer element 84 rests on the inner bottom surface 56 of the lower part 16 and is arranged below the locking element 54′. The second spacer element 86 is arranged above the locking element 54′. A part of the switching mechanism 14′, in this case the outer edge 36 of the snap-action disc 30, rests on the second spacer element 86. Both spacer elements 84, 86 are preferably configured as spacer rings.

(45) Otherwise, the closing lock 52′ works in the above-mentioned way and locks the switching mechanism 14′ after the switch 10 has been opened by means of the snap-action disc 30 due to temperature conditions.

(46) In the fourth embodiment of the switch 10 shown in FIG. 5, the closing lock 52′ is designed in the same or a similar way above the third embodiment of switch 10 shown in FIG. 4. According to the fourth embodiment, the switch 10 differs fundamentally in the layout of the housing 12″ and the switching mechanism 14″.

(47) The lower part 16″ is again made of an electrically conductive material. The flat upper part 18″ is instead made of an electrically insulating material. It is held to the lower part 16″ by a bent edge 88.

(48) Between the upper part 18″ and the lower part 16″, a spacer ring 22″ is provided here as well, which keeps the upper part 18″ at a distance from the lower part 16″. On its inner side, the upper part 18″ comprises a first stationary contact 48″ and a second stationary contact 50″. The contacts 48″ and 50″ are designed as rivets which extend through the upper part 18″ and end outside in the heads 92, 94, which serve for the external connection of the switch 10.

(49) The movable contact member 42″ in this case includes a current transfer member 96, which is in the embodiment shown in FIG. 5 a contact plate, the upper side of which is coated with an electrically conductive coating so that it provides an electrically conductive connection between the two contacts 48″ and 50″ in the contact position shown in FIG. 5 The current transfer member 96 is connected to the spring disc 28 and the snap-action disc 30 via a rivet 98, which is also to be regarded as part of the contact member 42″.

(50) An advantage of the switch design shown in FIG. 5 is that, in contrast to the first three embodiments of the switch shown in FIGS. 1-4, no current flows through either the spring disc 28 or the snap-action disc 30 when the switch is closed. This current flows only from the first external connection 92 via the first stationary contact 48″, the current transfer member 96 and the second stationary contact 50″ to the second external connection 94.

(51) It goes without saying that not only the embodiment of the closing lock 52′ shown in FIG. 4 can be used with the switch assembly shown in FIG. 5, but also the embodiments of the closing lock 52 shown in FIGS. 1-3.

(52) 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.

(53) 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.