Temperature-dependent switch

Abstract

A temperature-dependent switch has a first and a second stationary counter contact and a temperature-dependent switching mechanism with a contact member. The switching mechanism, in its first switching position, presses the contact member against the first counter contact and, in this case, produces an electrically conducting connection between the two counter contacts via the contact member. The switching mechanism, in its second switching position, holds the contact member at a spacing from the first counter contact. A closing lock is provided, which prevents the switch, once opened, from closing again. The closing lock locks the temperature-dependent switching mechanism permanently in the second switching position thereof in a mechanical manner.

Claims

1. A temperature-dependent switch comprising: a first stationary counter contact; a second stationary counter contact; a temperature-dependent switching mechanism having a first switching position and a second switching position, wherein: the temperature-dependent switching mechanism comprises a contact member, a temperature-dependent snap disc having a geometric high-temperature configuration and a geometric low-temperature configuration, and a temperature-independent spring disc at which the contact member is arranged, the spring disc has a first geometric configuration and a second geometric configuration, and the temperature-dependent switching mechanism is configured so that: in the first switching position, the spring disc is in the first geometric configuration and presses the contact member against the first stationary counter contact and produces an electrically conducting connection between the two stationary counter contacts via the contact member, and in the second switching position, the spring disc is in the second geometric configuration and holds the contact member spaced apart from the first stationary counter contact; a housing in which the two stationary counter contacts are provided, and in which the switching mechanism is arranged; and a closing lock that permanently locks the temperature-dependent switching mechanism in a mechanical manner, when the switching mechanism is in the second switching position, so as to prevent the switching mechanism once having moved to the second switching position from moving back to the first switching position, wherein: the closing lock comprises at least one first latching member arranged on the contact member and interacting with a second latching member, the first latching member is arranged in the housing, the second latching member is arranged in and connected to the housing, when the switching mechanism moves from the first switching position to the second switching position, at least one of the latching members radially and elastically yields to allow the latching members to slide into engagement with one another such that the contact member is permanently locked to the housing, and therefore the switching mechanism is permanently locked in the second switching position, and the latching members are selected from a group consisting of a circumferential groove, a circumferential bead, a resilient tongue, a recess, and a latching lug.

2. The switch of claim 1, wherein: the spring disc is a bistable spring disc, and the first and second geometric configuration are stable in a temperature-independent manner.

3. The switch of claim 2, wherein: the snap disc has an edge, and when transitioning from its geometric low-temperature configuration into its geometric high-temperature configuration, the snap disc is supported by its edge at a part of the switch and acts on the spring disc in such a way that the spring disc snaps from its first into its second geometric configuration.

4. The switch of claim 3, wherein the snap disc and the spring disc each have a center and are fixed to the contact member via their respective center.

5. The switch of claim 2, wherein: the contact member includes a movable contact part that interacts with the first stationary counter contact, and the spring disc interacts with the second stationary counter contact.

6. The switch of claim 5, wherein the spring disc has an edge and is in electrical contact with the second stationary counter contact via the edge, at least when the spring disc is in the low-temperature configuration.

7. The switch of claim 1, wherein the contact member includes a current transfer member that interacts with the first and second stationary counter contacts.

8. The switch of claim 1, wherein: the housing comprises a lower part and an upper part having an inner surface and closing the lower part, and the first stationary counter contact is arranged on the inner surface of the upper part.

9. The switch of claim 8, wherein the second stationary counter contact is arranged on the inner surface of the upper part.

10. The switch of claim 1, wherein the snap disc is one of a bi-metal snap disc and a tri-metal snap disc.

11. The switch of claim 1, wherein the closing lock interacts directly with the contact member.

12. The switch of claim 1, wherein the first latching member is arranged on an outer surface of the contact member.

13. The switch of claim 1, wherein the first latching member is arranged on an inner surface in a bottom opening of the contact member.

14. The switch of claim 8, wherein the closing lock comprises at least one locking member that interacts with the contact member and with a component that is arranged between the upper part and the lower part of the housing.

15. The switch of claim 14, wherein: the component includes a component disc with a through-opening for the contact member, the locking member comprises at least one radially outwardly resilient tongue, the tongue sits in the through-opening under tension when the temperature-dependent switching mechanism is in its first switching position, and the tongue is supported on an underside of the component disc when the temperature-dependent switching mechanism is in its second switching position.

16. The switch of claim 14, wherein the locking member is connected to the contact member.

17. The switch of claim 14, wherein: the locking member is connected to one disc of a spring disc and a snap disc, and the one disc carries the contact member.

18. The switch of claim 14, wherein: the component is configured as a spacer ring, the locking member comprises at least one radially outwardly resilient tongue that is arranged on the contact member which is configured as a current transfer member, the tongue abuts against an inner surface of the spacer ring under tension when the temperature-dependent switching mechanism is in its first switching position, and the tongue is supported on the spacer ring when the temperature-dependent switching mechanism is in its second switching position.

19. The switch of claim 14, wherein: the component is configured as a spacer ring, the locking member comprises at least one radially inwardly resilient tongue that is arranged on an inner surface of the spacer ring, the tongue abuts under tension against the contact member, which is configured as a current transfer member, when the temperature-dependent switching mechanism is in its first switching position, and the tongue is supported on the current transfer member when the temperature-dependent switching mechanism is in its second switching position.

20. The switch of claim 1, wherein the latching members are latching lugs.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention are shown in the drawings and will be explained in more detail in the following description. In the drawings:

(2) FIG. 1 shows a schematic side representation of a first embodiment of the novel switch in its low-temperature position;

(3) FIG. 2 shows a representation as FIG. 1, but with the novel switch in the high-temperature position;

(4) FIG. 3 shows a schematic side representation of a second embodiment of the novel switch in its low-temperature position;

(5) FIG. 4 shows a representation as in FIG. 3, but with the novel switch in the high-temperature position;

(6) FIG. 5 shows a representation as FIGS. 3 and 4 of the novel switch in its cooled-down position;

(7) FIGS. 6a and 6b show a first embodiment of a closing lock which can be used with the switches in FIGS. 1 to 5;

(8) FIGS. 7a and 7b show a second embodiment of a closing lock which can be used with the switches in FIGS. 1 to 5;

(9) FIGS. 8a and 8b show a third embodiment of a closing lock which can be used with the switches in FIGS. 1 to 5;

(10) FIGS. 9a and 9b show a fourth embodiment of a closing lock which can be used with the switches in FIGS. 1 to 5;

(11) FIGS. 10a and 10b show a fifth embodiment of a closing lock which can be used with the switches in FIGS. 1 to 5;

(12) FIG. 11 shows a sixth embodiment of a closing lock which can be used with the switches in FIGS. 1 to 5; and

(13) FIGS. 12a and 12b show a seventh embodiment of a closing lock which can be used with the switch in FIGS. 3 to 5.

DESCRIPTION OF PREFERRED EMBODIMENTS

(14) FIG. 1 shows a schematic, sectioned side view of a switch 10 which is realized in a rotationally symmetrical manner in top view and preferably comprises a circular form.

(15) The switch 10 comprises a housing 11 in which a temperature-dependent switching mechanism 12 is provided.

(16) The housing 11 includes a pot-like lower part 14 which is produced from electrically conducting material and a flat, insulating upper part 15 which is held on the lower part 14 by means of a bent-over edge 16. For reasons of clarity, the bent-over edge 16 is not shown solidly right across the upper part 15.

(17) A spacer ring 17, which holds the upper part 15 at a spacing from the lower part 14, is provided between the upper part 15 and the lower part 14.

(18) The upper part 15 comprises an inner surface 18 on which a first stationary counter contact 19 and a second stationary counter contact 21 are provided. The counter contacts 19 and 21 are realized as rivets which extend through the upper part 15 and end on the outside in heads 22 or 23 which serve for the external connection of the switch.

(19) The switching mechanism 12 includes, as a contact member, a current transfer member 24 which, in the shown embodiment, is a contact disc, the upper side 25 of which is coated in an electrically conducting manner so that in the case of the system shown in FIG. 1 it ensures an electrically conducting connection between the two counter contacts 19 and 21 at the counter contacts 19 and 21.

(20) The current transfer member 24 is connected via a rivet 26, which is also to be seen as part of the contact member, to a bistable spring disc 27 and a bistable snap disc 28.

(21) The spring disc 27 comprises two temperature-independent configurations, the first configuration of which is shown in FIG. 1 and the second configuration in FIG. 2.

(22) The snap disc 28 comprises two temperature-dependent configurations, namely its low-temperature configuration which is shown in FIG. 1 and its high-temperature configuration which is shown in FIG. 2.

(23) A circumferential shoulder 29, on which the spacer ring 17 rests, is provided in the inside of the lower part 14. The spring disc 27 is clamped by way of its edge 31 between the shoulder 29 and the spacer ring 17, whilst it rests by way of its center 32 on a shoulder 33 on the rivet 26. The spring disc 27 is consequently clamped at its center 32 between the current transfer member 24 and the shoulder 33.

(24) Another shoulder 34, on which the snap disc 28 rests by way of its center 35, can be seen in FIG. 1 further below and further radially outside on the rivet 26.

(25) The center 35 rests freely on the shoulder 34.

(26) The snap disc 28 lies freely above an inner bottom 37 of the lower part 14 by way of its edge 36.

(27) According to FIG. 1, the inner surface 37 is realized as a wedge-shaped support shoulder 38 which ascends radially outwardly and serves, as in the case of the shoulder disclosed in DE 10 2011 016 142 A1, as a support surface for the edge 36.

(28) The rivet 26 further comprises a bottom 42 which points to the inner bottom 37 but, in the low-temperature position of the switch 10 according to FIG. 1, is at a distance designated by reference numeral 43 from said inner bottom.

(29) When the temperature of the snap disc 28 then increases, its edge 36 in FIG. 1 is lifted upward such that the snap disc 26 snaps from its convex position shown in FIG. 1 into its concave position shown in FIG. 2 in which its edge 36 is supported against a part of the switch 10, in this case against the spring disc 27, as can be seen in FIG. 2.

(30) When transitioning from its low-temperature configuration in FIG. 1 into its high-temperature configuration in FIG. 2, the snap disc 28 is therefore supported by way of its edge 36 against the spring disc 27, pressing by way of its center 35 onto the shoulder 34 of the rivet 26 and, as a result, pressing the current transfer member 24 away from the stationary counter contacts 19 and 21 against the force of the spring disc 27.

(31) As a result of said movement, the rivet 26 is placed by way of its bottom 42 onto the inner bottom 37 of the lower part 14, at the same time the spring disc 27 snapping from its first configuration shown in FIG. 1 into its equally stable second geometric configuration which is shown in FIG. 2.

(32) Whilst the spring disc 27 holds the current transfer member 24 in abutment with the counter contacts 19 and 21 in its first configuration according to FIG. 1, it holds the current transfer member 24 at a distance from the counter contacts 19 and 21 in its second configuration according to FIG. 2 such that the switch 10 is open.

(33) Whilst the switch 10 is in its closed low-temperature position in FIG. 1, it is situated in its open high-temperature position in FIG. 2.

(34) When the temperature of the device to be protected and consequently the temperature of the switch 10 cools down again then, the snap disc 28 snaps from its high-temperature configuration according to FIG. 2 back again into its low-temperature configuration which it had already assumed in FIG. 1.

(35) The snap disc 28 is situated in its low-temperature configuration again to which it has cooled on account of the cooling of the device to be protected. The edge 36 of the snap disc 28 has moved downward in FIG. 2 and now rests on the supporting shoulder 38.

(36) The snap disc 28 will once again press the spring disc 27 into its first configuration when transitioning into its low-temperature configuration, as is the case with the switch according to DE 10 2011 016 142 A1.

(37) However, a closing lock 39, which is arranged in the region of the circles I, II, III, IV and V indicated in FIG. 2, is provided according to the invention. For reasons of clarity, different embodiments of the closing lock 39 are shown in FIGS. 6 to 12.

(38) Whilst a first embodiment of the novel switch 10 is shown in FIGS. 1 and 2, where a current transfer member 24 with rivet 26 is used as a contact member, FIGS. 3 to 5 show a second embodiment of the novel switch where a movable contact part 45, which is part of the switching mechanism 12, is used as a contact part.

(39) The switch 10 from FIG. 3 once again comprises a pot-like lower part 14, a spacer ring 17 which carries the upper part 15 with the interposition of an insulating film 46 once again resting on the circumferential shoulder 29 of which pot-like lower part.

(40) Lower part 14 and upper part 15 are produced here from electrically conducting material so that contact to an electrical device to be protected is able to be produced via their outer surfaces. The outer surfaces also serve at the same time for the electric external connection.

(41) The upper part 15 is held once again on the lower part 14 by the bent-over edge 16 of said lower part, one more insulating layer 47 being attached on the outside of the upper part 15.

(42) The switching mechanism 12 also includes the spring disc 27 and the snap disc 28 here, the spring disc 27 being clamped by way of its edge 31 between the shoulder 29 and the spacer ring 17.

(43) The spring disc 27 is fixed on the contact part 45 by way of its center 32, a ring 49 being pressed onto said contact part for this purpose.

(44) The ring 49 comprises a circumferential shoulder 51, on which the snap disc 28 rests by way of its center 35.

(45) In this way, the temperature-dependent switching mechanism 12 from FIG. 3 is a captive unit produced from contact member, spring disc 27 and snap disc 28 just as the switching mechanism 12 from FIGS. 1 and 2.

(46) When assembling the switches 10 and 10, the switching mechanism 12, 12 is able to be placed directly into the lower part 14, 14 as a unit.

(47) The movable contact part 45 interacts with a fixed counter contact 19 which is arranged on the inside of the upper part 15.

(48) The outer surface of the lower part 14, which is produced from electrically conducting material, serves as a second counter contact 21.

(49) In the position shown in FIG. 3, the switch 12 is situated in its low-temperature position in which the spring disc 27 is situated in its first configuration and the snap disc 28 is situated in its low-temperature configuration.

(50) The spring disc 27, in this case, presses the movable contact part 45 against the stationary counter contact 19.

(51) The movable contact part 45 comprises a bottom 52, which points to the inner bottom 37 of the lower part 14 and is at a distance from the same, as is comparable with the distance 43 in FIG. 1.

(52) A circumferential free space 40, which is provided in an edge region 41 of the inner bottom 37, is provided below the edge 36 of the snap disc 28

(53) The switch 10 described in this respect comprises roughly the same geometric features as an embodiment of a switch from DE 10 2013 101 392 A1 which was mentioned at the outset.

(54) In the case of the known switch, however, a wedge-shaped, circumferential supporting shoulder 38, which comprises the same function as the circumferential shoulder 29 in the case of the shoulder from the current FIGS. 1 and 2, is situated in the edge region 41. Said shoulder 38 is not provided in the novel switch 10.

(55) Because the spring disc 27 is clamped by way of its edge 31 between spacer ring 17 and shoulder 29, it is connected there to the lower part 14 in an electrically conducting manner with very low contact resistance.

(56) The spring disc 27 is clamped at its center 32 between the movable contact part 45 and the ring 49 so that, here too, a contact resistance that is very low electrically prevails.

(57) With the switch 10 in the closed low-temperature position according to FIG. 3, an electrically conducting connection is consequently produced between the counter contact 19 and the counter contact 22 via the movable contact part 45 and the spring disc 27.

(58) The snap disc 28, in this case, rests freely on the supporting shoulder 38 below the spring disc 27.

(59) If the temperature of the device to be protected and consequently the temperature of the snap disc 28 is then increased, said snap disc snaps from the convex low-temperature configuration shown in FIG. 3 into its concave high-temperature configuration which is shown in FIG. 4.

(60) During said snapping action, the snap disc 28 is supported by way of its edge 36 on part of the switch 10, in this case on the edge 31 of the spring disc 27.

(61) By way of its center 35, the snap disc 28, in this case, presses onto the shoulder 51 and consequently lifts the movable contact part 45 from the stationary contact part 19.

(62) As a result, it deflects the spring disc 27 downward at its center 32 at the same time so that the spring disc 27 snaps from its first stable geometric configuration in FIG. 3 into its second geometrically stable configuration in FIG. 4.

(63) In said second configuration, the spring disc 27 presses the bottom 52 of the contact part 45 against the inner bottom 37 of the lower part 14.

(64) FIG. 4 therefore shows the high-temperature position of the switch 10 in which said switch is open.

(65) If the device to be protected and consequently the snap disc 28 then cool down again, the snap disc 28 snaps into its low-temperature position again, as shown for example in FIG. 3. To this end, the edge 36 in FIG. 4 is moved downward and consequently into the free space 40.

(66) The switch 10 is then situated in its cooled-down position which is shown in FIG. 5.

(67) The spring disc 27 is still in its geometrically stable second configuration in which it holds the contact part 45 at a distance from the counter contact 19, the contact part 45 resting by way of its bottom 52 on the inner bottom 37 of the lower part 14.

(68) The snap disc 28 is situated in its low-temperature configuration again, having moved with its edge 36 into the free space 40. The snap disc 28 is consequently not capable of pressing the contact part 45 or the spring disc 27 upward at its center 32 in FIG. 5.

(69) Closing locks 39, which are arranged in the region of the circles VI, VII, VIII, IX and X indicated in FIG. 5, are also provided again in the case of the switch 10 from FIGS. 3 to 5. For reasons of clarity, schematic representations of different embodiments of the closing locks 39 used here are also shown in FIGS. 6 to 11.

(70) It is the job of the closing locks 39 to lock the temperature-dependent switching mechanism 12, 12 permanently in the high-temperature position in a mechanical manner in a switch 10, 10 that has been opened once such that it is not able to close again even when the snap disc 28 cools down.

(71) Whilst in the case of the switch 10 in FIGS. 1 and 2 the closing locks 39 have to absorb the closing pressure exerted by the cooled snap disc 28 in a permanent manner, said closing pressure does not exist in the case of the switch 10 in FIGS. 3 to 5 because the edge 36 of the snap disc 28 does not find any supporting shoulder 38 but rather comes to rest in the free space 40.

(72) FIG. 6 shows in a schematic side view a contact member 55 which comprises an outer surface 54 and is to symbolize the movable contact part 45 from FIG. 5, the rivet 26 from FIG. 2 or the current transfer member 24 from FIG. 2. A component 56 of the switch 10 or 10, which symbolizes a latching carrier in FIG. 6a which is arranged on the bottom 37, and the spacer ring 17 of the switch 10 in FIG. 2, is indicated parallel to the outer surface 54. The component 56 is therefore arranged in the switch 10, 10 and is connected to said switch.

(73) The closing lock 39, which interacts here directly with the contact member 55, is realized between component 56 and contact member 55. The closing lock 39 includes a first latching member, which is arranged on the outer surface 54, and a second latching member, which is attached to the component 56, more precisely to the outer surface 59 thereof.

(74) In FIG. 6 the latching members are realized as latching lugs 57, 58 which slide past one another when the switch is opened, to which end they are realized in a resilient or elastically yielding manner. In FIG. 6a the switch 10, 10 is situated in the closed state according to FIG. 1 or 3, and in FIG. 6b in the open state according to FIG. 2, 4 or 5.

(75) In FIG. 6b the latching lugs 57, 58 are latched together such that the contact member 55 is no longer able to be moved upward (that is to say to close the switch 10, 10) because it is permanently locked to the component 56 in a mechanical manner.

(76) The representations in FIGS. 7 and 8 correspond to those from FIG. 6, only bar the latching members being realized as circumferential groove 61 or circumferential bead 62. In FIG. 7 the groove 61 is arranged on the contact member 55 and in FIG. 8a on the component 56.

(77) The bead 61 consists of elastic material and is consequently radially yielding. It slides along the outer surface 54 or 59 when the switch 10, 10 is opened until it engages in the groove 62 and locks the contact member 55 permanently to the component 56 in a mechanical manner.

(78) The representations in FIGS. 9 and 10 also correspond to those from FIG. 6, only bar the latching members being realized here as a locking member in the form of a resilient tongue 68 or recess 69. The recess 69 is arranged on the contact member 55 in FIG. 9 and on the component 56 in FIG. 10.

(79) The resilient tongue 68 is radially yielding. It abuts against the outer surface 54 or 59 under tension and slides along past the outer surface 54 or 59 when the switch 10, 10 is opened until it engages in the recess 69 and locks the contact member 55 permanently on the component 56 in a mechanical manner.

(80) The closing locks 39 from FIGS. 6 to 10 can be realized in the circles I to IV, VI and VII.

(81) FIG. 11 shows a schematic side view of a contact member 55 which comprises a preferably central bottom opening 64 and is to symbolize the movable contact part 45 from FIG. 3 or the rivet 26 from FIG. 1. The bottom opening 64 comprises an inner surface 65 and sits on a journal 66 which is fastened to the inner bottom 37 of the switch 10, 10 and comprises an outer surface 67.

(82) The latching members 57, 58; 61, 62 from FIGS. 6 to 10 can be arranged on the inner surface 65 and the outer surface 67 in order to lock the contact member 55 mechanically to the bottom 37 when the switch 10, 10 has moved for the first time into its high-temperature position in which the contact member rests on the bottom 37.

(83) The locking lock 39 from FIG. 11 can be realized in the circles V and VIII.

(84) FIG. 12 shows a schematic side view of details of the switch 10 from FIGS. 3 to 5 in the region of the movable contact part 45, FIG. 12a corresponding to the low-temperature position and FIG. 12b to the high-temperature position.

(85) The insulating film 46, in which a through-opening 71 is provided, through which the contact part 45 moves in abutment with the counter contact 19, can be seen above the contact part 45. Multiple locking members 72, which are realized as flexible tongues and are arranged in the manner of a crown or a feather duster, are arranged distributed around the contact part 45.

(86) The flexible tongues extend upward at an angle from a ring 73, by means of which they are fastened to the contact part 45 and/or to the spring disc 27. In the low-temperature position in FIG. 12a, the flexible tongues extend through the through-opening 71 and are mechanically functionless.

(87) When the switch 10 opens, the contact part 45 is moved downward into the high-temperature position in FIG. 12b. In this case, the flexible tongues are released from the through-opening 71 and are moved radially outward under the underside 74 of the insulating film 46.

(88) When the switch 10 cools down again and the spring disc 27 would snap into its low-temperature configuration again on account of a strong vibration, the switch would nevertheless not be able to re-close because the locking members 72 act as spacers and prevent the contact part 45 from moving upward.

(89) The switch 10 is locked permanently in its high-temperature position in a mechanical manner in this way too.

(90) The closing lock 39 from FIG. 12 can be realized in the circles IX and X.