Temperature-dependent switch with cutting burr

Abstract

A temperature-dependent switch has a housing with a cover part having a lower side and an upper side and with an electrically conductive lower part having a circumferential shoulder and a circumferential wall with an upper section that overlaps the cover part. The switch has a first external contact surface on the upper side of the cover part and a second external contact surface externally on the housing, wherein the upper section of the circumferential wall presses the cover part onto the circumferential shoulder. A temperature-dependent switching mechanism is arranged in the housing and, depending on its temperature, establishes or opens an electrically conductive connection between the first and second external contact surfaces. A circumferential cutting burr is arranged on the shoulder in the lower part.

Claims

1. A temperature-dependent switch, comprising: a housing comprising an electrically conductive lower part and a cover part made of an electrically insulating material, wherein the cover part has a lower side and an upper side, wherein the lower part has a circumferential shoulder and a circumferential wall, wherein the cover part lies with its lower side on the circumferential shoulder, and wherein the circumferential wall of the lower part has an upper section overlapping the cover part and pressing the cover part onto the circumferential shoulder, at least one first external contact surface being arranged on the upper side of the cover part, at least one second external contact surface being provided externally on the housing, a temperature-dependent switching mechanism being arranged in the housing, wherein the switching mechanism, depending on its temperature, establishes or opens an electrically conductive connection between the at least one first external contact surface and the at least one second external contact surface, and a first sharp-edged cutting burr being arranged on the circumferential shoulder in the lower part, wherein the first sharp-edged cutting burr is configured to form a mechanical barrier between the cover part and the lower part by the first sharp-edged cutting burr cutting into the lower side of the cover part.

2. The switch of claim 1, wherein the first sharp-edged cutting burr is circumferentially closed in itself.

3. The switch of claim 1, wherein the first sharp-edged cutting burr is formed integrally with the circumferential shoulder in the lower part.

4. The switch of claim 1, wherein the first sharp-edged cutting burr comprises a cutting edge configured to cut into the lower side of the cover part.

5. The switch of claim 1, wherein the electrically insulating material is a plastic material.

6. The switch of claim 1, wherein a second sharp-edged cutting burr is arranged on the lower side of the cover part.

7. The switch of claim 6, wherein the second sharp-edged cutting burr is circumferentially closed in itself.

8. The switch of claim 7, wherein the second sharp-edged cutting burr is radially spaced from the first sharp-edged cutting burr.

9. The switch of claim 6, wherein the second sharp-edged cutting burr protrudes from the lower side to a height of between 10 m and 50 m.

10. The switch of claim 1, wherein the first sharp-edged cutting burr protrudes above the circumferential shoulder to a height of between 10 m and 50 m.

11. The switch of claim 1, wherein the at least one second external contact surface is arranged on the upper side of the cover part.

12. The switch of claim 1, wherein the switching mechanism carries a current transfer member configured to interact with a first stationary counter contact and a second stationary counter contact arranged on the lower side of the cover part, wherein the first stationary counter contact is connected to the at least one first external contact surface, and wherein the second stationary counter contact is connected to the at least one second external contact surface.

13. The switch of claim 1, wherein the switching mechanism comprises a bimetal part.

14. The switch of claim 1, wherein the switching mechanism comprises a snap-action spring disk.

15. The switch of claim 1, wherein the first sharp-edged cutting burr (i) is circumferentially closed in itself, (ii) is formed integrally with the circumferential shoulder in the lower part and (iii) is a turned part created together with the lower part by turning.

16. The switch of claim 1, wherein the first sharp-edged cutting burr protrudes from a top surface of the circumferential shoulder in the lower part in a direction toward the upper section of the lower part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention are represented in the drawing, and are explained in more detail in the description below. Here:

(2) FIG. 1 shows a schematic sectional view from the side of a new temperature-dependent switch;

(3) FIG. 2 shows a schematic, enlarged view of the detail II of FIG. 1; and

(4) FIG. 3 shows a schematic, partly sectional partial view from the side of a further, new temperature-dependent switch.

DESCRIPTION OF PREFERRED EMBODIMENTS

(5) FIG. 1 shows a schematic side section, not true to scale, of a temperature-dependent switch 10 which is circular when viewed from above.

(6) The switch 10 comprises a temperature-dependent switching mechanism 11 that is arranged in a housing 12, in which an insulating foil 13 is arranged which extends between a pot-like, electrically conductive lower part 14 and an electrically conductive cover part 15 that closes the lower part 14.

(7) A circumferential lower shoulder 16 and a circumferential upper shoulder 17 are provided in the lower part 14, on which upper shoulder the cover part 15 lies, with the insulating foil 13 placed between, the edge region 18 of which foil extends to the upper side 21 of the cover part 15.

(8) The lower part 14 comprises a circumferential wall 19, whose upper section 20 overlaps the cover part 15. The upper section 20 is folded radially inwards in such a way that, by way of the intermediate insulating foil 13, it presses the cover part 15 onto the circumferential shoulder 17 if, compared to the situation shown schematically in FIG. 1, it is folded further onto the upper side 21.

(9) In the embodiment illustrated, the lower part 14 and the cover part 15 are made of electrically conductive material, for which reason the insulating foil 13 is provided; it runs around the cover part 15 and extends inside the housing 12 parallel to the cover part 15, is brought upwards to the side between the wall 19 and the cover part 15, and faces upward with its edge region 18.

(10) The upper section 20 of the wall 19 thus lies flat on the edge region 18 of the insulating foil 13, and presses this in the direction of the upper side 21 of the cover part 14.

(11) A further insulating cover 22 is provided on the upper side 21 of the cover part 15, extending radially outwards to the edge region 18 of the insulating foil 13.

(12) A stationary counter-contact 24 is arranged on the lower side 23 of the cover part 15, and interacts with a movable contact part 25 carried by the switching mechanism 11.

(13) The switching mechanism 11 comprises a snap-action spring disk 26 which is supported by its edge 27 on the lower shoulder 16, making an electrically conductive connection there.

(14) A bimetal snap-action disk 28, which has two geometrical temperature positions, the low-temperature position illustrated in FIG. 1 and a high-temperature position, not illustrated, is provided underneath the snap-action spring disk 26, that is to say on its side that faces away from the stationary counter-contact 24.

(15) The bimetal snap-action disk 28 lies with its edge 29 freely above a wedge-shaped circumferential shoulder 31, which is formed on an inner floor 32 of the lower part 14.

(16) The lower part 14 has an external floor 33 with which thermal contact is established to a device that is to be protected.

(17) The bimetal snap-action disk 28 is supported by its center 35 on a circumferential shoulder 34 of the contact part 25.

(18) The snap-action spring disk 26 is connected through its inner region 36 at its center permanently to the movable contact part 25, for which purpose a ring 37, on which the shoulder 34 is formed, is pressed onto its stud 30 which protrudes through the two snap-action disks 26 and 28.

(19) The stationary counter-contact 24, which is connected in an electrically conductive manner to the upper side 21 of the cover part 15, interacts with the movable contact part 25 and, through that, with the inner region 36 of the snap-action spring disk 26, which, in the closed state of the switch 10 illustrated in FIG. 1, is in continuous electrical contact with the shoulder 16 and, through this, with the lower part 14.

(20) The upper side 21 acts as the first external contact surface 38, as is indicated by an area of lengthways stripes. The external floor 33 of the lower part 14 can act as the second external contact surface of the switch 10, while it is provided with the switch 10 that the upper section 20 of the wall 19 is used as the second external contact surface 39.

(21) In the closed switch position of the switch 10 shown in FIG. 1, the movable contact part 25 is pressed by the snap-action spring disk 26 against the stationary counter-contact 24. Since the edge 27 of the electrically conductive snap-action spring disk 26 is in contact with the lower part 14, an electrically conductive connection is established between the two external contact surfaces 38, 39.

(22) When the temperature inside the switch 10 now increases beyond the response temperature of the bimetal snap-action disk 28 it flips from the convex configuration shown in FIG. 1 into a concave configuration in which its edge 29 in FIG. 1 moves upwards, so that it moves from below to rest against the edge 27 of the snap-action spring disk 26.

(23) The bimetal snap-action disk 28 now presses with its center 35 on the shoulder 34, and thus lifts the movable contact part 25 from the stationary counter-contact 24.

(24) The snap-action spring disk 26 can be a bi-stable spring disk which is also geometrically stable when the switch is in its open position, so that the movable contact part 25 then does not come to rest against the stationary counter-contact 24 when the edge 29 of the bimetal snap-action disk 28 no longer presses against the edge 27 of the snap-action spring disk 26.

(25) If the temperature inside the switch 10 now falls again, then the edge 29 of the bimetal snap-action disk 26 moves downwards, and comes to rest against the wedge-shaped shoulder 31. The bimetal snap-action disk 26 now presses with its center 35 from below against the snap-action spring disk 26, and pushes this back into its other geometrically stable position, in which, as in FIG. 1, the movable contact part 25 presses against the stationary counter-contact 24.

(26) In the present embodiment, the switching mechanism 11 comprises, in addition to the bimetal snap-action disk 28, the current-carrying snap-action spring disk 26, while it is also possible for the switching mechanism 11 only to be provided with the bimetal snap-action disk 28, which then would lie with its edge 29 against the shoulder 16 and would carry current.

(27) It is also possible for the bimetal snap-action disk 28 to be arranged above the snap-action spring disk 26.

(28) The detail II of the switch 10 from FIG. 1 is shown enlarged in FIG. 2.

(29) The region of the switch 10 from FIG. 1 is shown enlarged in FIG. 2, where the cover part 15 lies on the shoulder 17 with the insulating foil 13 in between.

(30) A cutting burr 41 is provided radially inwards on the shoulder 17, which protrudes perpendicularly in the direction of the cover part 15 above the shoulder 17, and has penetrated about one third of the way into the insulating foil 13.

(31) A further cutting burr 42 is provided on the lower side 23 of the cover part 15 radially outside, extending perpendicularly above the lower side 23 in the direction of the lower part 14, and also penetrating about one third of the way into the insulating foil 13.

(32) The two cutting burrs 41 and 42 have an upper cutting edge 43, and have an approximately triangular form in their cross-section.

(33) The two cutting burrs 41 and 42 are closed in itself and run radially around, so that each forms an annular cutting burr 41 or 42, each of which comprises an upward-facing annular cutting edge 43.

(34) The cutting burr 42 has a height above the lower side 43 of about 30 m, indicated by 51. The cutting burr 41 also has a height 52 protruding beyond the shoulder 17, which is also about 30 m. The insulating foil 13 has a thickness, indicated by 53, that is about 100 m.

(35) At their base, where they are formed integrally with the shoulder 17 or the lower side 23 respectively, the cutting burrs 41 and 42 respectively have a width indicated by 54 and 55 respectively that corresponds approximately to the height 52 or 51 respectively.

(36) The two cutting burrs 41 and 42 each form a mechanical barrier to the possible ingress of contamination, in particular liquids, that could penetrate between the insulating foil 13 and either the cover part 15 or the lower part 14 into the interior of the switch.

(37) Since the two cutting burrs 41 and 42 are closed in itself, they form a complete mechanical barrier that cannot be passed by contamination, in particular liquids.

(38) Whereas in FIG. 2 both the cover part 15 and the lower part 14 consist of electrically conductive material, and therefore have to be insulated from one another by the insulating foil 13, FIG. 3 shows, in principle, a sectional view of part of the upper region of a switch 10 in which the lower part 14 again consists of metal, but in which however a cover part 44 consisting of plastic is provided.

(39) The cover part 44 rests with its lower side 23 directly on the shoulder 17 in the lower part 14; the shoulder 17 is again provided with the cutting burr 41 already known from FIG. 2, the upper cutting edge 43 of which has cut into the material of the cover part 14.

(40) The cover part 44 is being held on shoulder 17 by the folded upper section 20 of the circumferential wall. During assembly of the new switch 10, the cutting burr 41 penetrates into the material of the cover part 44, and forms a mechanical barrier against the penetration of liquids between the cover part 44 and the lower part 14.

(41) The cutting burr 41 of the embodiment according to FIG. 3 again is closed in itself. Whereas the cutting burr 41 in FIG. 3 lies radially inwards on the shoulder 17, it can here also be arranged centrally or radially to the outside.

(42) It is also to be mentioned that the shape of the cutting burrs 41 and 42 is adapted to the material into which they are to penetrate.

(43) Whereas in the switch 10 from FIG. 1, an external contact surface 38 is arranged on the upper side 21 of the cover, and the other external contact surface 39 is formed on the wall 19, the switch 10 of FIG. 3 comprises two external contact surfaces 45, 46 which are both arranged next to one another on the upper side 21 of the cover part 44.

(44) The two external contact surfaces 45 and 46 are each joined to stationary counter-contacts 47 and 48 which are arranged on the lower side 23 of the cover part 44 and which interact with a current transfer member 49 that is pressed by a snap-action spring disk 26 against the stationary counter contacts 47, 48.

(45) In the switch 10, the operating current thus does not flow through the snap-action spring disk 26, but through the current-transfer member 49.

(46) In the closed state of the switch 10 shown in FIG. 3, the snap-action spring disk 26 is supported by its edge 27 on the lower shoulder 16 in the lower part 14, and presses the current transfer member 49 against the two stationary counter-contacts 47, 48.