EP0794546B1 - Switch with a temperature sensitive switching mechanism - Google Patents

Abstract

The switch has a temp. dependent switch mechanism (12) in a housing (11). The housing has a lower part (14) on whose base (15) is arranged a first counter-contact (16) for the switch mechanism. The housing also has a cover (17) to close the lower part (14). A second counter-contact (19) for the switch mechanism is arranged on the inside of the cover. The switch mechanism makes an electrically conductive connection between the two contacts (16,19) in dependence on its temperature. The lower part (14) of the housing (11) is made of insulating material. The first counter contact (16) can be contacted from outside through a wall (13) of the lower part (14). The cover part (17) is made of electrically conductive material and also acts as the second counter-contact (19). The cover part is held on an upper edge of the lower part (14).

Description

The present invention relates to a switch with a a temperature-dependent switchgear housing that has a lower part, on the inner bottom of a first Counter contact for the rear derailleur is arranged, as well as a Cover part closing bottom part includes, on the inside a second counter contact is provided for the switching mechanism, the switching mechanism depending on its temperature electrically conductive connection between the two mating contacts manufactures that can be contacted from the outside.

Such a switch is known from DE 37 10 672 A1.

In the known switch, the housing has an electrical made of conductive material and a lower part closing lid part, which is made of insulating material is. The rear derailleur is arranged in this housing Includes spring washer, which carries a movable contact part. The spring washer works against a bimetallic snap washer, which is put over the movable contact part. Below The switching temperature presses the spring washer, which is on the ground supports the lower part, the movable contact part against one Counter contact, which is provided on the inside of the cover part and itself in the manner of a rivet through the lid to the outside extends. The bottom of the lower part serves as another counter contact for the rear derailleur.

Because the spring washer itself made of electrically conductive material is manufactured, it maintains the response temperature of the Switchgear for a low-resistance, electrically conductive connection between the mating contact on the cover part and the Mating contact on the lower part, the lower part from the outside is contacted. Now the temperature of the rear derailleur increases, the bimetallic snap disc snaps suddenly and pushes the movable contact part against the force of the Spring washer away from the mating contact of the cover, so that the electrical connection is interrupted.

Such switches are generally used for temperature monitoring used by electrical devices. As long as the temperature of the electrical device a predetermined response temperature does not exceed, the switch remains closed in line with the consumer to be protected is switched. Now the temperature of the consumer increases impermissible, the bimetallic snap disk snaps and thus interrupts the flow of electricity to the consumer.

The known switch has the disadvantage that its manufacture is relatively expensive. This is mainly due to the fact that after the counter contact after the manufacture of the cover part must be attached to the cover part, while at the same time for an electrically conductive connection through the wall of the cover part through to the outside. This happens after Kind of a rivet outside the lid in a head passes over, soldered to the strands, crimp connections etc. can. This assembly of the mating contact on the cover part takes place usually manually and is therefore very expensive.

Another switch, according to the preamble of claim 1, is known from DE 21 21 802 A1, in whose housing is also a temperature-dependent as described above Rear derailleur is arranged. At this switch are Lid part and lower part are both pot-shaped and made made of electrically conductive material. Both on the top as well as to the lower part are one-piece crimp connections integrally formed, whereby the crimp connection of the lower part through a corresponding notch in the wall of the upper part after extends outside. Between the top and the bottom is an insulating film is arranged around the two housing parts electrically isolate from each other.

The temperature-dependent switching mechanism now contacts on the one hand over the spring washer the lower part and on the other hand over the Movable contact part, the cover part, so that an electrical there is a conductive connection between the two crimp connections, as long as the temperature of the switch mechanism is below the response temperature lies. If the temperature of the rear derailleur rises, so this electrical connection is made as described above interrupted.

With this switch, too, the final assembly is due to the one to be inserted Insulating film is very complex and therefore only manual perform. This manual final assembly is not only cost-intensive, it also leads to assembly errors and thus to one higher committee.

Another disadvantage of both switches described so far is that they are additional in certain applications still need to be isolated to the outside because the current flow over the electrically conductive lower part is made.

Another temperature-dependent is known from US 4,490,704 Known switch, the lower housing part made of insulating material and has a lid made of metal on one shoulder of the lower part rests and from an edge of the lower part is held. The temperature-dependent switching mechanism includes one bimetal spring clamped on one side, at its free end maintains a moving contact that is below the response temperature of the rear derailleur with a fixed counter contact Is plant, which is arranged on the inside of the lid.

The bimetal spring is firmly clamped at its other end and connected to a resistor connected to the bottom of the Lower part runs. There is a through hole in the bottom provided, in the bottom of a button-like connector is plugged in. With its protruding inside the switch This connector is head soldered to the resistor. The button-like head merges into a flap that goes underneath the wall of the lower part runs through and next to the lower part merges into a connection flag.

So this document describes a completely different, temperature-dependent one Rear derailleur as the two publications cited above, because of the one-sided clamped bimetal spring lower requirements for the isolation of the rear derailleur the different switching states are to be set.

The contacting of the clamped end of the bimetal spring is very expensive because of the button-like connector, it not only are complicated shaped parts required that Montage is designed because of the soldering of the button-like Head with the resistance inside the lower part very consuming. Another disadvantage of this switch is that it is not isolated both upwards and downwards, so that when it is attached to a device to be protected special precautions are required.

Against this background, it is an object of the present invention to further develop the aforementioned switch such that it is inexpensive to assemble with simple design effort.

According to the invention, this object is achieved with the above-mentioned Switch solved in that the lower part made of insulating material is made, the first counter contact through a wall of the Lower part can be contacted from the outside, and that Cover part is made of electrically conductive material as well at the same time acts as a second counter contact, the cover part is preferably inserted into the lower part and on or from an upper edge of the lower part is held.

The object on which the invention is based is achieved in this way completely solved. Because the lower part is now made of insulating material is made, no insulation sheet is required to cover a appropriate electrical insulation between the lower part and To worry about the cover part. Another advantage is that the cover part itself acts as a counter contact, so that when State of the art elaborate through-plating Cover part is omitted. This contacting from the outside can with the lower part much easier e.g. achieve by that a slot is provided in the wall of the lower part, through which a connecting part of the first mating contact follows extends outside. So the bottom part can be used as a pot with a Longitudinal slot are made in its outer wall, then the first counter contact only has to be inserted in such a way that its outwardly projecting connector lies in the slot. Then the bimetal rear derailleur is then preferably in reverse order as previously known and finally the lid part follows, which is on the edge of the Lower part is held directly, where e.g. locking lugs are provided. The entire assembly of the new switch is therefore very simple, with relatively few components required be, so that the cost of the new switch as a result keep its simple construction very low.

The outer bottom of the lower part can be used as an insulating support surface be used so that the new switch is easier can be mounted on a device to be protected.

It is preferred if the first counter contact in the Lower part by casting or injection molding during manufacture of the lower part is held so captive that it is an integral part of the lower part.

The advantage here is that the lower part is now e.g. as a plastic molded part can be manufactured, whereby during the Injection molding the first mating contact directly overmolded so that it becomes an integral part of the lower part. In other words, during the manufacture of this base is the attachment of the mating contact to the Bottom of the lower part realized, so that several Operations can be saved. In addition, the first mating contact through the extrusion coating to the outside completely isolated so that a subsequent isolation by epoxy or an insulating cap, as was previously known, is eliminated.

In a further development it is preferred if the first counter contact an integrally formed, through a wall of the lower part externally projecting connector.

The advantage here is that both the assembly of the first counter contact on the lower part as well as its plated-through hole through the wall to the outside during the manufacture of the lower part can be implemented integrally in one work step. The Mating contacts with molded connection parts can e.g. taped delivered on the line, whereupon a spraying machine one counter contact after the other with the lower housing part molded. Then all that has to be done in this lower part Bimetal rear derailleur are inserted, whereupon it then with the lid part is closed, the second at the same time Counter contact works. Overall, there are very few Manufacturing steps in the entire manufacture of the new Switch, so the cost of this switch is very low can be held.

In a preferred embodiment, the first counter contact is one electrically conductive ring or an electrically conductive Washer, wherein it is preferably designed as a stamped sheet metal part, on which the connector is integrally formed. Also the second counter contact is preferably used as a stamped sheet metal part molded connection part formed.

On the one hand, these measures are constructively advantageous, because Disks and rings, preferably as sheet metal stampings particularly easy and inexpensive to manufacture and easy to shed or overmolded, so that the manufacture of the lower part with integral counter contact arranged therein is inexpensive and easy to implement. The connector then extends automatically after such production through a side wall of the lower part to the outside.

When training as a disc it is also advantageous that better thermal connection of the new switch the bottom of the lower part made of insulating material through to that with regard to its temperature development protective device results than with a ring.

However, if the first mating contact is designed as a ring, the result is there is a large free area of insulating material in the middle, with which the movable contact part of the bimetal rear derailleur can get into plant without it being an electrical Contact with the mating contact, so here on the otherwise required insulating washer between the Bimetal rear derailleur and the cover part can be dispensed with.

In the rear derailleur, it is namely preferred if there is a electrically conductive spring washer which includes a movable Contact part carries and against a bimetallic snap disc works, which sits approximately in the middle on the movable contact part, wherein the spring washer with its edge on a mating contact supports and the movable contact part against the other Counter contact presses when the rear derailleur is below it Response temperature.

Such bimetallic rear derailleurs are generally state of the art known in the art, they have the advantage that the Current flows through the spring washer, so that the bimetal snap disk undergoes no self-heating and thus not disadvantageous in terms of their response behavior or is influenced unpredictably. If such a rear derailleur is now located in the new switch, so the is supported Spring washer on the first counter contact and presses it movable contact part against the second counter contact. at The bimetallic snap disk snaps when the temperature of the rear derailleur rises around and now supports itself with its edge inside on the cover part and presses the movable contact part with the spring washer pointing down to the bottom of the lower part. If the first counter contact is now designed as a ring, so the movable contact part does not come with it now in plant, so that the electrical connection between external connections of the new switch is broken, though the spring washer with its edge on the inside of the cover part supported.

If the first counter contact because of the better heat transfer is designed as a disc, so only an insulating disc inserted between the bimetallic snap disk and the cover part to make contact in the high temperature position Edge of the spring washer and second counter contact and thus one prevent unwanted short circuit.

In a further development, however, it is preferred if the first Counter contact has an approximately central contact projection, with which the movable contact part of the rear derailleur below of whose response temperature is in the system.

The advantage here is that the rear derailleur, so to speak, "overhead" is inserted into the housing so that the spring washer below the response temperature with its edge on the Supported cover part. An advantage of this arrangement is that easy assembly, because now the bimetal snap disc can be placed in the lower part where it may centered on the contact tab. Then the Spring washer inserted with welded-on contact part in the opening of the bimetallic snap disc also automatically centered so that the assembly of the new switch is now automatic is possible. In a further development, the lower part now overlaps the first Counter contact ring-shaped, so that an insulating contact area is formed on the first counter contact.

The advantage here is that this insulating support area same while spraying or pouring the lower part can be produced, which makes the use of a additional insulating washer is unnecessary. If the rear derailleur now is installed "upside down" in the housing, so the Spring washer with its edge below the response temperature on the cover part and presses the movable contact part against the contact advantage. Is above the response temperature now the spring washer with its edge on the insulating Support area so that despite the plant of the middle Area of the spring washer and bimetallic snap washer on the Cover part no longer a short circuit between the two mating contacts can occur. Because of this very simple The measure therefore reduces the effort once again Final assembly of the new switch considerably. Also increase quality and productivity because while the insulating cap during the production process for known switches and / or film are mechanically stressed, whereby Can form cracks that lead to short circuits. These problems do not occur with the new switch.

It is particularly noteworthy here that the number of operations is drastically reduced after overmolding the first Counter contact only has to have a bimetallic snap disc and spring washer are inserted into the lower part, which then only has to be closed with the cover part. These operations are now so simple that they can be easily automated are.

However, the cost advantage of the new switch is not only in the small number of assembly steps and the ability to be automated assembly, another advantage achieved that the insulating washer is now completely dispensed with can be. This insulating washer must be in the prior art a whole range of requirements regarding dielectric strength etc. meet so that they are a very expensive component whose price is noticeable in the total price of the known Switches down. So now on this insulating washer can be dispensed with, this also reduces costs of the new switch once again considerably.

In general, it is preferred if the cover part on an inner Shoulder of the lower housing part rests, the edge of the Lower housing part preferably after inserting the cover part is hot stamped or welded.

One of these measures is simple positioning of the lid part possible, by hot stamping or On the other hand, heat welding provides a significantly better hold on the Cover part is reached on the lower part than this the latches mentioned above would be the case. It will also the incorporated rear derailleur electrically isolated and special well sealed against external influences.

Further features and advantages result from the description and the attached drawing.

It is understood that the above and those below Features still to be explained not only in the respective specified combinations, but also in other combinations or can be used alone without the scope of the to leave the present invention.

Fig. 1

den neuen Schalter in einem ersten Ausführungsbeispiel, in einer schematischen Schnittdarstellung in Seitenansicht; und

Fig. 2

in einer Darstellung wie Fig. 1 ein zweites Ausführungsbeispiel des neuen Schalters.

Embodiments of the invention are shown in the accompanying drawing and are explained in more detail in the following description. Show it:

Fig. 1

the new switch in a first embodiment, in a schematic sectional view in side view; and

Fig. 2

in a representation like Fig. 1, a second embodiment of the new switch.

In Fig. 1, a switch is shown at 10, in its housing 11, a temperature-dependent switching mechanism 12 is arranged. Such switches are e.g. to monitor the temperature of electrically operated devices and to this Purpose electrically connected in series with the device.

The housing 11 comprises a lower part having a wall 13 14, on the inner bottom 15 of a first counter contact 16 for the switching mechanism 12 is arranged. The lower part 14 is through a cover part 17 closed, on the inside 18 a second counter contact 19 is provided.

While the lower part 14 made of electrically insulating material is made, the cover part 17 is electrically conductive, so that it acts as a second counter contact.

The first mating contact 16 is designed as a ring 21, the Connection part 22 through a slot 23 in the wall 13 after extends outside. When installing switch 10, the ring 21 inserted into the interior of the lower part 14 that the Connector 22 slides down through the slot 23. This Slot 23 can be made very thin, so that it Function of the new switch is not affected. However, it is possible after inserting the first mating contact 16 Shed slot 23 or hot stamp.

The second mating contact 19 is designed as a disk 24 which with its edge 25 on an inner circumferential shoulder 26 of the lower part 14 supports. The edge 25 of the disc 24 will surmounted by an edge 27 of the lower part 14. On this edge 27 locking lugs 28 are provided which the disc 24 captive hold on shoulder 26.

In Fig. 1 it can still be seen that a connecting part 29 of the second counter-contact 19 is located within the edge 27 extends above where it can be contacted appropriately can.

The switching mechanism 12 comprises a spring washer 31 which is movable Contact part 32 carries that in the embodiment shown is welded to the spring washer 31. The spring washer 31 is supported with its edge 33 on the ring 21 and presses in the low temperature position shown in Fig. 1 the movable contact part 32 against the disc 24, so that a total of 31 via the electrically conductive spring washer electrical connection between the connecting parts 22 and 29 will be produced.

About the movable contact part 32 are a bimetallic snap disk 34 as well as an insulating washer 35.

Now the temperature of the switch 10 rises above the Response temperature of the switching mechanism 12, so it snaps Bimetallic snap disk 34 suddenly turns around and is now supported with its edge 36 over the insulating washer 35 on the inside 18 of the lid part 17. The bimetal snap disc presses the movable contact part 32 against the force of Spring washer 31 away from the washer 24, which is the second counter contact forms. This way the electrical connection interrupted between the two connecting parts 22 and 29.

When assembling the switch shown in Fig. 1 is first the first contact part 16 inserted into the lower part 14 before then spring washer 31, bimetallic snap disk 34 and insulating washer 35 can be inserted. Then the cover part 17 inserted into the edge 27 of the lower part 14 and so far pressed down so that the locking lugs 28 the disc 24th reach over and hold captive, so "snap".

2 is another embodiment of the new Switch 10 shown, in which the first counter contact as Washer 37 is formed. The disc 37 is on its edges overlapped annularly by the lower housing part 14, so that a insulating support area 38 is formed, which is the pane 37 also isolated at the top.

The disc 37 also has a contact projection approximately in the center 39, which points into the interior of the housing 11.

In the embodiment of Fig. 1, the counter contact 16 now molded in the manufacture of the lower part 14 or encapsulated so that it is an integral part of the lower part 14 is.

The bimetal rear derailleur is in FIG. 2 compared to FIG. 1 so to speak inserted "overhead" so that the movable contact part 32 with the low-temperature position shown in FIG the contact projection 39 is in plant. The spring washer 31 supports with its edge 33 on the inside of the cover part 17, so that a conductive connection between the connection parts 22, 29 is produced, both of them laterally through the wall 13 of the lower part 14 extend.

The connecting part 29 is not in one in FIG. 2 discerning notch in the edge 27 so that it can be added can be used from above. It can be seen that the Edge 27 overlaps the disc 24 at its edge and thus it holds captive. This attachment is achieved that an originally straight edge 27 after the Inserting the disk 24 is hot stamped or hot welded is so that it at least partially overlaps the disc 24. If the edge 27 is pulled up accordingly, so much can Insulating material should be provided that the disc 24 after is insulated on the outside when the edge 27 is hot stamped.

In other words, this type of assembly becomes a switch completely insulated from the outside, from which only the two connecting parts 22 and 29 protrude. Since both counter contacts 16 and 19 as disks 37 and 24, respectively trained, is still a good thermal connection possible to the outside.

Due to the isolating support area 39, the switch 10 from FIG. 2 also to the insulating disk shown in FIG. 1 35 can be dispensed with. If now the rear derailleur 12 so is heated far that the bimetallic snap disk 34 in their high temperature position changes, so this is supported then on the insulating support area 38 and presses it movable contact part 32 away from the contact projection 39 until finally also the spring washer 31 from the concave shown jumps into a convex shape. Spring washer 31 and bimetallic snap washer 34 are now leaning against it with their edges isolating contact area 38, so that a possibly possible System in the area of the movable contact part 32 to the Cover part 17 does not cause an undesirable short circuit between the two connecting parts 22 and 29 leads.

Claims (12)

1. A switch, having a housing (11) receiving a temperature-dependent switching mechanism (12), said housing comprising a lower part (14), a first countercontact (16) for said switching mechanism (12) being arranged at an inner base (15) of said lower part, and a cover part (17) closing off said lower part (14), a second countercontact (19) for said switching mechanism (12) being arranged at an inner side (18) of said cover part, whereby said switching mechanism (12) as a function of its temperature creates an electrically conductive connection between said two countercontacts (16,19) which can be contacted from outside,
      characterized in that said lower part (14) is made of insulating material, contact to said first countercontact (16) being possible through a wall (13) of said lower part (14) from outside, and that the cover part (17) is made of electrically conductive material and concurrently serves as said second countercontact (19), whereby said cover part (17) is being held at an upper rim (27) of said lower part (14).
2. The switch of claim 1, characterized in that said first countercontact (16) is held in lossproof fashion in the lower part (14) by injection-embedding or molding during production of said lower part (14), such that it is an integral component of said lower part (14).
3. The switch of claim 1 or claim 2, characterized in that said first countercontact (16) has a shaped-on connector element (22) that projects outward through a wall (13) of said lower part (14).
4. The switch of anyone of claims 1 - 3, characterized in that the first countercontact (16) is configured as an electrically conductive ring (21).
5. The switch of anyone of claims 1 - 3, characterized in that the first countercontact (16) is configured as an electrically conductive disk (37).
6. The switch of anyone of claims 3 - 5, characterized in that the first countercontact (16) is a punched sheet-metal part on which the connector element (22) is integrally configured.
7. The switch of anyone of claims 1 - 6, characterized in that the second countercontact (19) is a punched sheet-metal part with a shaped-on connector element (29).
8. The switch of anyone of claims 1 - 7, characterized in that the cover part (17) rests on an inner shoulder (26) of said lower part (14).
9. The switch of anyone of claims 1 - 8, characterized in that said rim (27) is hot-pressed or welded after introduction of said cover part (17).
10. The switch of anyone of claims 1 - 9, characterized in that the switching mechanism comprises an electrically conductive spring disk (31) which carries a movable contact element (32) and operates against a bimetallic snap disc (34) that sits approximately centeredly on the movable contact element (32), the spring disk (31) being braced at its rim (33) against one countercontact (16, 19) and the movable contact element (32) pressing against the other countercontact (16, 19) when the switching mechanism (12) is below its response temperature.
11. The switch of anyone of claims 1 - 10, characterized in that said first countercontact (16) has an approximately centered contact projection (39) with which a movable contact element (32) of said switching mechanism (12) is in contact below its response temperature.
12. The switch of anyone of claims 1 - 11, characterized in that said lower part (14) overlaps said first countercontact (16) in annular fashion such that an insulating contact region (38) is formed on said first countercontact (16).

Images