EP0887827B1 - Switch with a temperature sensitive switching mechanism - Google Patents

Abstract

The switch (10) has a temperature-dependent switch mechanism (12) contained within a housing (11) provided by a base (14) with a counter-contact (16) on its inside surface and a cooperating cover (17). The cover has a second counter-contact (19) on the inside (18). The switch mechanism employs a conductive spring disc (31) carrying a movable contact (32) and a bimetallic snap-action disc (34), fitted around the outside of the movable contact. The spring disc acts against one counter-contact at its edge (33) and presses the movable contact against the other counter-contact below the response temperature of the bimetallic snap-action disc. The counter-contact against which the edge of the spring disc acts is magnetic.

Description

The present invention relates to a switch with a a temperature-dependent switching mechanism receiving housing, the a lower part, at the inner bottom of a first Counter contact is arranged for the rear derailleur, as well as a Lower part closing lid part comprises, at the Inside a second mating contact for the rear derailleur is provided, wherein the derailleur is an electrically conductive Spring washer includes, which carries a movable contact part and works against a bimetal snap-action, which is about sits centrally on the movable contact part, wherein the Spring washer with its edge supported on a mating contact and the movable contact part against the other counter contact presses when the rear derailleur is below its Response temperature is.

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

In the known switch, the housing has a electrically conductive material manufactured lower part and a the lower part occlusive lid part on, the off Insulating material is made. In this case that is Rear derailleur arranged, which includes a spring washer, a carries movable contact part. The spring washer works against a bimetal snap-action disc, which over the movable Contact part is slipped. Below the switching temperature pushes the spring washer, which is located at the bottom of the base supports, the movable contact part against a Mating contact, which is provided on the inside of the lid 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.

Since the spring washer itself is made of electrically conductive material made, it maintains the response temperature of the maintenance Derailleur for a low-resistance, electrically conductive Connection between the mating contact on the cover part and the mating contact on the lower part, wherein the lower part of outside is contacted. Now the temperature of the Derailleur increases, so snaps the bimetallic snap disk suddenly and pushes the movable contact against the Force of the spring washer away from the mating contact of the lid, so that the electrical connection is interrupted.

Such switches are generally used for temperature monitoring used by electrical equipment. As long as the temperature of the electrical device a predetermined response temperature does not exceed, the switch remains closed, the to this purpose in series with the consumer to be protected is switched. Now increases the temperature of the Inadmissible consumer, so snaps the bimetallic snap disk and thus interrupts the flow of current to the Consumer.

In the known switch is a disadvantage that his Manufacturing is relatively expensive. This is mainly because that after the manufacture of the cover part then the Mating contact must be attached to the lid part, wherein at the same time for an electrically conductive connection the wall of the lid part is to provide through to the outside. This happens in the manner of a rivet, outside the Cover turns into a head, on the strands, Crimp connections etc. can be soldered. This assembly the mating contact on the cover part is usually done manually and is therefore very expensive.

From DE 21 21 802 A1, another switch is known, in its housing also a as described above Temperature-dependent switching mechanism is arranged. In this Switch lid part and lower part are both pot-like formed and made of electrically conductive material. Both the upper part and the lower part are integrally formed crimp connections, wherein the Crimp connection of the lower part by a corresponding Notch in the wall of the upper part extends to the outside. Between the upper part and the lower part is an insulating film arranged to electrically power the two housing parts isolate against each other.

The temperature-dependent derailleur now contacts one hand on the spring washer, the lower part and on the other hand over the movable contact part of the cover part, so that an electric conductive connection between the two crimp terminals exists as long as the temperature of the rear derailleur below the response temperature is. Increases the temperature of the Schaltwerkes, so this electrical connection is in interrupted as described above.

Also with this switch is the final assembly because of the einzulegenden Insulating foil very expensive and therefore only manually perform. This manual final assembly is not only wage-intensive, It also leads to assembly errors and thus to a higher committee.

Another disadvantage of both so far described switch is that in certain applications in addition still must be isolated to the outside, since the Current flow via the electrically conductive lower part takes place.

From US 4,490,704 is another temperature-dependent Switch known, the housing lower part Insulating material and a lid made of metal, the rests on a shoulder of the lower part and of a Edge of the lower part is held. The temperature-dependent Derailleur includes a cantilevered bi-metal spring, which holds a moving contact at its free end, the below the response temperature of the rear derailleur with a fixed counter contact in plant, the inside of the lid is arranged.

At its other end, the bimetallic spring is firmly clamped and connected to a resistor at the bottom of the Lower part runs. There is a through hole in the floor provided in the bottom of a button-like connector is inserted. With his in the interior of the switch projecting head is this connector to the resistor soldered. The button-like head goes over into a flap that runs laterally under the wall of the lower part and merges next to the lower part in a connecting lug.

So this document describes a completely different temperature-dependent rear derailleur as the two cited above Pamphlets, wherein because of the cantilevered Bimetallic spring has lower insulation requirements Schaltwerkes in the different switching states too are.

The contacting of the clamped end of the bimetallic spring is very expensive because of the button-like connection part, it Not only are complex molded parts required Assembly is due to the soldering of the button-like Head with the resistance in the interior of the lower part very much consuming. Another disadvantage of this switch exists in that he does not work both up and down is isolated so that when attached to a protective device required special precautions are.

Another disadvantage with the two first described Switches results from the fact that is desirable in itself, that the bimetal snap disc mechanically unloaded and so to speak, freely inserted into the housing, so that mechanical loads do not shift the Switching temperature can lead, as is the case also discussed switch with the cantilevered Bimetallic spring is the case. If, however, switch with such loosely inserted bimetallic snap disk in the range of alternating magnetic fields can be used, so the Bimetallic snap disk can be put into vibration because they due to their composition by a magnetic field can be magnetized. In other words, the bimetallic snap disk is magnetized by the external magnetic field and follow its vibrations.

However, such bimetallic snap disk vibrations are unwanted, since they load them mechanically, resulting in a Shortening the service life and an uncontrolled shift the switching temperature can lead. To such influences to suppress, become temperature-dependent switches of the type mentioned therefore often with a magnetic Protective shield, it is also known insert another stabilizing disc, the bimetallic snap disc below their response temperature keeps vibration free. This further holder of the bimetallic snap disk However, on the one hand structurally complex and on the other hand has the undesirable side effect that the bimetallic snap disk but what is burdened by the loose insertion should actually be prevented.

In this context, it is from DE 196 36 320 A1 at a temperature-dependent switch with one-sided clamped spring tongue and freely inserted bimetallic strip known, a holding or guiding part of spring tongue and / or bimetallic strips of magnetic material finished. The spring tongue carries here in per se known Make a moving contact with a firm contact in Appendix, the spring tongue is clamped to its End and the fixed contact each with an external connection are connected. The loosely inserted, at his Narrow sides however led bimetallic strips raises at one Inadmissible temperature increase the moving contact of the firm contact.

The magnetized holding or guiding part is now located next to one of the two narrow sides of the bimetallic strip, being due to a mutual magnetic attraction between the bimetal strip and the holding or Guide member prevents vibrations of the bimetallic strip should be.

Also with this switch is on the one hand its complex structure disadvantageous, wherein by the mechanical clamping on Holding end of the spring tongue here, the switching temperature unpredictable being affected. Another disadvantage with this Switch is that the attraction between the holding and guiding part and the bimetallic strip often is not enough, because these two parts are very geometric unfavorable to each other. The desired suppression of Therefore, vibration is often not achieved with this switch.

Against this background, it is an object of the present invention to develop the switch mentioned in the beginning in such a way that in a structurally simple way vibrations of Bimetallic snap disk can be prevented.

According to the invention, this object is achieved in the aforementioned Switch achieved in that the mating contact on which the spring washer below the response temperature with their Edge is magnetic.

The problem underlying the invention is based on this Completely solved.

In fact, the inventor of the present application has recognized that is a clear better attraction between the bimetallic snap disk and a magnetic part of the Switch when this magnetic part is arranged flat under the bimetallic snap disk. On Surprisingly simple, this arrangement is achieved by that the existing counter-contact in his anyway Function is expanded by now being designed "magnetic" is.

The term "magnetic" in the sense of this application both Magnetizable materials, ie those with high Permeability, ferromagnetic materials, etc. understood as well as permanent magnets. All that matters is that that the material from which at rest the Spring washer supporting mating contact is made, a magnetic attraction to the interposition the spring washer overlying bimetallic snap disk can exercise. This mating contact is now very close to the Bimetallic snap disk, so that through this geometrically very effective arrangement already a low magnetization is sufficient to vibrate the bimetallic snap disk too prevent it being mechanically overstressed mechanically. A big advantage of the new switch is that it constructively does not have to be changed at all, rather only has to be a suitable material for the mating contact be selected, this counter contact if necessary before or must still be magnetized after assembly, so that at most one further production step is required.

In itself, it is not even necessary that of magnetic Pre-magnetize material manufactured counter contact, namely, when the switch in a magnetic alternating field device, this automatically causes the magnetization both the bimetallic snap disk and the mating contact, whereby then the desired attraction effect is achieved. On the other hand, it is desirable if the switch with already magnetized counter contact is delivered, because then because the bimetal snap-action contactless is held in position, so that also mechanical shocks not negative on the switching temperature or Life of the bimetallic snap disk can affect.

It is preferred if the lower part of Insulating material is made, the first counter contact by a wall of the lower part through contactable from the outside is, and the cover part of electrically conductive material is made and at the same time as a second mating contact acts, wherein the lid part at an upper edge of Lower part is held.

Since the lower part is now made of insulating material is no insulating film required for a corresponding electrical insulation between the lower part and the lid part too to care. Another advantage is that the Cover part itself acts as a mating contact, so that the at State of the art complex through-hole through the Cover part is omitted. This contacting from the outside can be significantly simpler at the bottom, e.g. thereby achieve that a slot is provided in the wall of the lower part, through a connecting part of the first mating contact itself extends to the outside. The lower part can therefore as a pot with be made a longitudinal slot in its outer wall, in which case the first mating contact is merely inserted in this way must be that its outwardly projecting connector in the Slot lies. Then then the bimetal derailleur preferably in reverse order as before general known inserted and finally follows the lid part, the is held directly on the edge of the lower part, where there e.g. Latches are provided. The entire assembly of the new Switch is thus very simple, although relatively few Components are needed so that the cost of the new switch due to its simple construction very much keep low.

It is preferred if the first mating contact in the Lower part by casting or encapsulation during manufacture the lower part is held captive so that he integral part of the lower part is.

Here it is advantageous that the lower part is now e.g. as a plastic injection molding can be made, during the Injection process of the first mating contact umittelbar umspritzbar becomes so that it becomes an integral part of the lower part. In other words, while making this Lower part is at the same time the attachment of the Gegenkontaktes realized at the bottom of the lower part, so that several operations can be saved here. In addition, the first mating contact by the Insulation completely isolated to the outside, so that a subsequent insulation by epoxy or an insulating cap, as it was previously known, is eliminated.

In a development, it is preferred if the first Counter contact a molded, through a wall of the lower part having outwardly projecting connection part.

Here is an advantage that both the assembly of the first Mating contact on the lower part and its via through the wall to the outside during the production of the Lower part are realized integrally in one operation can. The mating contacts with molded connection parts can e.g. strapped to be delivered to the band, whereupon a Spraying machine one mating contact after another with the Enclosed bottom part. Then must in this lower part only the bimetallic rear derailleur is inserted, whereupon it is then closed with the lid part, the simultaneously acts as a second mating contact. Overall result Thus, very few manufacturing steps in the entire production of the new switch, so that the cost can be kept very low for this switch.

In a preferred embodiment, the first mating contact is included an electrically conductive ring or an electrically conductive Disc, preferably integrally with the connecting part is trained. Also the second counter contact is preferably formed integrally with the connection part.

These measures are on the one hand a constructive advantage, because Slices and rings are particularly easy and inexpensive to make and easy to shed or overmold so that the manufacture of the lower part with integral therein Counter contact very inexpensive and easy to implement is. The connecting part extends after such Production then automatically by a side wall of the Lower part through to the outside.

In the training as a disk is also advantageous that a better thermal connection of the new switch through the bottom of the lower part made of insulating material therethrough with respect to its temperature development device to be protected results in a ring.

However, if the first mating contact is designed as a ring, then results in its middle a large free area Insulating material, with which the movable contact part of the bimetallic switching mechanism can get into contact without it makes electrical contact with the mating contact, so that here on the otherwise possibly required insulating dispensed between the bimetal rear derailleur and the cover part can be.

If the first mating contact because of better heat transfer is designed as a disc, so only one must Insulating washer between the bimetallic snap disk and the Cover part are inserted to in the high temperature position a contact between the edge of the spring washer and the second Counter contact and thus to prevent an unwanted short circuit.

In a development, it is preferred, however, if the first mating contact an approximately central contact projection having, with the movable contact part of the switching mechanism is below its response temperature in plant.

Here is an advantage that the rear derailleur so to speak "over Head "is inserted into the housing, so that the Spring washer below the response temperature now with its edge is supported on the cover part. An advantage of this Arrangement lies in the simple assembly, since now first the bimetallic snap disc are inserted into the lower part can where it possibly centered on the contact projection. Then then the spring washer with welded Contact part inserted, located in the opening of the bimetallic snap disk also automatically centered, so that the Assembly of the new switch is now automatically possible.

In a further development, the lower part now overlaps the first counter contact annular, so that an insulating Support area is formed on the first mating contact.

The advantage here is that this insulating support area during injection or casting of the lower part same can be mitgefertigt, which reduces the use of a additional insulating disc is unnecessary. If the rear derailleur is now installed "overhead" in the housing, so supports the spring washer below the response temperature with its edge on the lid part and pushes the movable Contact part against the contact tab. Above the Response temperature is now the spring washer with her Edge on the insulating support area, so that despite the plant of the middle area of spring washer and Bimetallic snap-action disc on the cover part no short circuit more can occur between the two mating contacts. By This structurally very simple measure is thus reduced once again the effort in the final assembly of the new Switch considerably. Also increase thereby also the Quality and productivity since during the Production process in known switches the insulating cap and / or film are mechanically stressed, resulting in Can form cracks that lead to short circuits. These Problems do not occur with the new switch.

Particularly noteworthy here is that the number of Operations is drastically reduced after overmolding the first mating contact only need bimetallic snap disk and spring washer inserted in the lower part be, then only with the lid part close is. These operations are now like this simple, that they can be easily automated.

The extent described mechanical structure of the new Schalters is the subject of unpublished German Patent Application 196 09 310. In the there described switches, the mating contacts, however, as Sheet metal stampings formed, so have none Magnetizability on.

The inventor of the present application has now recognized that this mechanical construction has particular advantages in Related to the present invention underlying idea, namely one of Magnetically form mating contacts. Depending on the orientation the rear derailleur in the housing will either be on the ground of the lower part made of insulating material injected Counter contact or serving as a mating contact Cover part made of magnetic material and possibly magnetized after manufacture, as mentioned above has been. Both mating contacts are very close to the bimetallic snap disk, so that even small magnetic forces Sufficient to hold the bimetallic snap disk in its rest position to fix, ie against mechanical or magnetic Alternating fields to protect induced vibrations. In particular, the cover part can also be subsequently easily magnetize because it is direct from the outside is accessible, so that magnetizing coils very close the lid part can be brought up without disturb intervening insulation layers, as in the in the lower part provided counter contact would be the case.

Further features and advantages emerge from the Description and attached drawing.

It is understood that the above and the hereinafter to be explained features not only in the each specified combinations, but also in others Combinations or alone, without to leave the scope of 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 illustrated in the accompanying drawings 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 10 is shown in the housing 11 a temperature-dependent switching mechanism 12 is arranged. Such switches are e.g. for monitoring the temperature used by electrically powered devices and to this Purpose electrically connected in series with the device.

The housing 11 comprises a wall 13 having a lower part 14, at the inner bottom 15, a first counter-contact 16 for the rear derailleur 12 is arranged. The lower part 14 is through a lid part 17 is closed, on the inside 18 a second mating contact 19 is provided.

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

The first mating contact 16 is formed as a ring 21, whose Connecting part 22 through a slot 23 in the wall 13th extends to the outside. When mounting the switch 10 is the ring 21 is inserted into the interior of the lower part 14, that the connecting part 22 through the slot 23 down slides. This slot 23 can be made very thin, so that he does not have the function of the new switch impaired. It is possible, however, after inserting the first counter contact 16 to shed the slot 23 or hot to emboss.

The second mating contact 19 is designed as a disk 24, with their edge 25 on an inner, circumferential Shoulder 26 of the lower part 14 is supported. The edge 25 of the Disk 24 is from an edge 27 of the lower part 14th surmounted. At this edge 27 locking lugs 28 are provided which hold the disc 24 captive on the shoulder 26.

In Fig. 1 can still be seen that a connection part 29 of the second mating contact 19 within the edge 27 after extends above where it is contacted in a suitable manner can.

The derailleur 12 includes a spring washer 31, which is a movable Contact part 32 carries that shown in the Embodiment is welded to the spring washer 31. The spring washer 31 is supported by its edge 33 on the Ring 21 and presses in the one shown in Fig. 1 Low temperature position the movable contact part 32 against the disc 24, so that a total of the electrically conductive Spring washer 31 an electrical connection between the Connecting parts 22 and 29 is made.

About the movable contact part 32 are a bimetallic snap disk 34 and an insulating 35 slipped.

Now increases the temperature of the switch 10 on the Response temperature of the rear derailleur 12, so snaps the bimetallic snap disk 34 suddenly turns around and rests now with its edge 36 on the insulating 35 at the Inside 18 of the lid part 17 from. The presses Bimetal snap disk, the movable contact part 32 against the force of the spring washer 31 away from the disc 24, the forms second mating contact. In this way, the electrical connection between the two connection parts 22nd and 29 interrupted.

When assembling the switch shown in Fig. 1 is first the first contact part 16 is inserted into the lower part 14, before then spring washer 31, bimetallic snap disk 34 and insulating 35 are inserted. Subsequently is still the lid part 17 in the edge 27 of the lower part 14th inserted and pushed down so far that the locking lugs 28 overlap the disc 24 and hold captive, so "Snap".

In Fig. 2 is another embodiment of the new Switch 10 shown in which also the first mating contact than Disc 37 is formed. The disc 37 is at her Edges are annularly overlapped by the lower housing part 14, so that an insulating support area 38 is formed, which is the Disc 37 also insulated at the top.

Approximately in the middle, the disc 37 still has a contact projection 39, which points into the interior of the housing 11.

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

The bimetallic switching mechanism is compared with FIG. 1 in FIG. 2 inserted so to speak "overhead", so that the movable contact part 32 at the low temperature position shown in FIG is in contact with the contact projection 39. The Spring washer 31 is supported with its edge 33 inside of the Cover part 17 from, so that a conductive connection between the connecting parts 22, 29 is made, both extend laterally through the wall 13 of the lower part 14.

The connector 29 is not in a in Fig. 2 recognizable notch in the edge 27 so that it later can be used from above. It is recognizable, that the edge 27, the disc 24 overlaps at its edge and she thus remains captive. This attachment is characterized achieved that an originally straight upstanding edge 27th hot stamped or hot welded after inserting the disc 24 is so that he at least partially the disc 24 overlaps. If the edge 27 is raised accordingly, can also be provided so much insulating material, that also the disc 24 is isolated to the outside when the edge 27th is hot stamped.

In other words, this way of assembling becomes one Outwardly completely isolated switch created from the only still the two connecting parts 22 and 29th protrude. Since both mating contacts 16 and 19 as discs 37 or 24 are formed, is still a good thermal Connection to the outside possible.

By the insulating support portion 39 may in the Switch 10 of FIG. 2 also to those still shown in Fig. 1 Insulating washer 35 can be dispensed with. If now that is the Rear derailleur 12 is heated so far that the bimetallic snap disk 34 changes to its high temperature position, it then rests on the insulating support area 38 and presses the movable contact part 32 of the contact projection 39 away, until finally the spring washer 31 of the concave shown in a convex shape umspringt. Spring washer 31 and bimetallic snap disk 34 are supported now with their edges on the insulating support area 38 so that any possible installation in the area of the movable ' Contact part 32 to the lid part 17 not to a unwanted short circuit between the two connecting parts 22 and 29 leads.

According to the invention, the mating contact on which the spring washer 31 below the response temperature of the bimetallic snap disk 34 is supported, made of magnetized or magnetizable Material made with high magnetic permeability and after assembly of the switch 10, if necessary magnetized. In the embodiment of FIG. 1 is therefore the mating contact 16 and in the embodiment of FIG. 2 of the mating contact 19, so the lid member 17 itself magnetic. The thus magnetized cover part 17 and the magnetic Ring 21 now pull the likewise magnetic bimetallic snap disk 34 on, so that these in magnetic Alternating fields or other mechanical Vibrations are not put into vibration. Especially the subsequent magnetization is easy the embodiment of FIG. 2, because there is to be magnetized Counter contact 19 in the form of the cover part 17 also from the outside for magnetizing coils is easily accessible.

Claims (11)

1. A switch (10) having a housing (11) for containing a temperature-dependent switching mechanism (12), said housing comprising a lower part (14) on whose inner bottom (15) a first countercontact (16) for said switching mechanism (12) is arranged, and having a cover part (17) closing off said lower part (14), on an inner side (18) of said upper part there being provided a second countercontact (19) for said switching mechanism (12), whereby said switching mechanism comprises an electrically conductive spring disk (31) which carries a movable contact element (32) and operates against a bimetallic snap disk (34) which sits approximately centeredly on the movable contact part (32), whereby said spring disk (31) is braced with its rim (33) against one of the countercontacts (16, 19) and presses the movable contact element (32) against the other countercontact (19, 16) when the switching mechanism (12) is below its response temperature,
   characterized in that the countercontact (16, 19) against which the spring disk (31) is braced at its rim (33) below the response temperature is magnetic.
2. The switch of claim 1, characterized in that the lower part (14) is produced from insulating material, said first countercontact (16) is contactable from outside through a wall (13) of the lower part (14), and the cover part (17) is produced from electrically conductive material and simultaneously acts as the second countercontact (19), whereby the cover part (17) is retained on an upper rim (27) of said lower part (14).
3. The switch of claim 2, characterized in that the cover part (17) is magnetic.
4. The switch of claim 1 or 2, characterized in that the first countercontact (16) is retained in lossproof fashion in the lower part (14) by encapsulation or injection-embedding during manufacture of the lower part (14), in such a way that it is an integral component of the lower part (14).
5. The switch of anyone of claims 2 through 4, characterized in that the first countercontact (16) has a shaped-on connector element (22) projecting to outside through a wall (13) of the lower part (14).
6. The switch of anyone of claims 1 through 5, characterized in that the first countercontact (16) is configured as an electrically conductive ring (21).
7. The switch of anyone of claims 1 through 5, characterized in that the first countercontact (16) is configured as an electrically conductive disk (37).
8. The switch of anyone of claims 5 through 7, characterized in that the first countercontact (16) is configured integrally with the connector element (22).
9. The switch of anyone of claims 1 through 8, characterized in that the second countercontact (19) has a shaped-on connector element (29).
10. The switch of anyone of claims 1 through 9, characterized in that the first countercontact (16) has an approximately centered contact projection (39) with which the movable contact element (32) of the switching mechanism (12) is in contact below the response temperature of the switching mechanism.
11. The switch of anyone of claims 1 through 10, characterized in that the lower part (14) overlaps the first countercontact (16) in annular fashion, thus constituting an insulating support region (38) on the first countercontact (16).

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