EP2874171B1 - Temperature-dependent switching device - Google Patents

Description

The present invention relates to a temperature-dependent switching mechanism with a bimetallic snap disk and a movable contact member and preferably a spring snap-action disc.

Such a temperature-dependent switching mechanism and a temperature-dependent switch equipped therewith are, for example, from the DE 43 45 350 A1 known.

The known temperature-dependent switch comprises a housing with a metallic lower part and a metallic cover part. In the housing, a temperature-dependent switching mechanism is housed, which produces an electrically conductive connection between the lower part and the cover part of the housing as a function of its temperature.

The rear derailleur is equipped with a spring snap-action disc and a bimetal snap-action disc. The spring snap-action disc carries as a contact member a so-called movable contact part, which is pressed by the spring washer against a stationary counter contact inside of the cover part, which has a first contact surface forms. With its edge, the spring snap-action disc is supported on a second contact surface in the lower part of the housing, so that the electric current flows from the lower part through the spring snap-action disc and the movable contact part into the stationary counter-contact and from there into the cover part.

The lower part of the housing is pot-shaped, it has on its inner side a circumferential shoulder on which rests the spring snap-action disc of the temperature-dependent switching mechanism.

The spring snap disc carries a centrally welded contact part over which the bimetallic snap disk is slipped, so that it rests loosely on the spring snap disk.

The cover part of the housing rests on another circumferential shoulder of the lower part. Because the lower part and the cover part of the housing are made of electrically conductive material, an insulating film is arranged between them, the lower part and the cover part of the housing electrically insulated from each other.

The outer side of the cover part of the housing serves as a first external connection, where a first stranded wire is soldered. The outer side of the lower part serves as a second outer terminal, where a terminal lug is attached, to which a second pigtail is soldered.

The known temperature-dependent switch is used to protect electrical equipment from overheating. For this purpose, it is mounted on the device to be protected so that it is in thermal contact with the device.

The power supply circuit of the device is routed through the temperature-dependent switch by connecting a device connection cable to one of the external connections of the switch and the other external connection of the switch to the power supply for the device.

Because of the thermal coupling, the temperature-dependent switch always assumes the temperature of the electrical device to be protected. If the temperature of the device now rises above a predetermined response temperature, the bimetallic snap-action disc jumps into its high-temperature position, in which it opens the switch, so that the supply circuit of the device is interrupted, which consequently can not heat up further.

In this construction, the bimetallic snap-action disc is mounted mechanically force-free below its transition temperature, wherein the bimetallic snap disk is not used to conduct the operating current of the device to be protected.

It is advantageous that the bimetallic snap discs have a long mechanical life, and that the switching point, so the transition temperature of the bimetallic snap disk, not changed even after many switching cycles.

Moreover, it is known to provide such switches with a parallel resistor which is connected in parallel with the external terminals. When the switch is open, this parallel resistor takes over part of the operating current and keeps the switch at a temperature above the transition temperature, so that the switch does not automatically close again after cooling down. Such switches are called self-holding.

It is also known to provide such switches with a series resistance, which is traversed by the current flowing through the switch operating current. In this way, an ohmic heat is generated in the series resistor, which is proportional to the square of the flowing operating current. If the current exceeds a permissible level, the heat of the series resistance causes the switching mechanism to open.

In this way, a device to be protected is already switched off from its supply circuit when too high current flow is recorded, which has not yet led to excessive heating of the device.

Notwithstanding the design of the switch according to DE 43 45 350 A1 The temperature-dependent switching mechanism may also comprise only a bimetallic snap-action disk which carries the movable contact part and thus carries the operating current.

If the temperature-dependent switch is to carry particularly high currents, a current transfer element in the form of a contact bridge or a contact plate is frequently used as the contact element, which is moved by a spring part, that is to say a spring snap-action disc and / or a bimetallic snap-action disc and carries two contact parts. which cooperate with two stationary mating contacts, which are electrically connected to the external terminals of the switch.

In this way, the operating current of the device to be protected flows from the first mating contact via the first contact part into the contact plate, through it to the second contact part and from this into the second mating contact. The spring part is thus de-energized.

It is also known to form a contact bridge on the spring part itself, so for example, the bimetallic snap disk or working against a bimetal Federschnappscheibe, which is therefore not a separate component. Then the operating current flows through the so-equipped spring snap disk.

All these different design variants can be realized with the switch according to the invention.

The switching function of the DE 43 45 350 A1 Known switching mechanism can only be reliably tested when the switch has been completely assembled.

Thus, the immediately apparent disadvantage is associated that both in problems with the contact of the movable contact part and / or the spring snap-action disc as well as in case of malfunction or incorrect installation of the bimetallic snap disk, the entire switch must be discarded.

Although the known temperature-dependent switching mechanism and the thus equipped, known temperature-dependent switch functionally meet all requirements, there is therefore a need to improve the testability and the installation.

Another disadvantage of the known switch is the fact that at least the lower part of the housing must be made very precisely so that the spring snap disc can be supported with its edge securely on the circumferential shoulder. Against this background, the lower parts of the known temperature-dependent switch turned parts, usually made of brass, which means a high-precision manufacturing, but is associated with high production and unit costs.

Although such temperature-dependent switches have proven very successful in everyday use, the assembly of the switch is time-consuming and costly, with testing of the known switch is possible only after complete assembly.

From the DE 195 27 254 A1 is a temperature-dependent switch with a temperature-dependent switching mechanism receiving housing known. The temperature-dependent switching mechanism has a bimetallic snap-action disc and a spring snap-action disc, both of which are held captive on a movable contact part. The bimetallic snap disk lies with its edge between a shoulder on an annular insulating ring and a cover of the housing. Below the bimetallic snap disk is the spring snap disk, which is arranged with its edge loose between a lying on the inner bottom of the housing base contact ring and an electrically conductive spacer ring. The relative position of bimetallic snap disk and spring snap disk to each other can also be reversed.

From the DE 86 90 150 U1 It is known to arrange a rectangular bimetallic snap disk below a support plate and to hold loose there by means of a holder whose side walls engage over the side edges of the bimetallic snap disk.

From the DE 20 2005 019 880 U1 It is known to arrange a round bimetallic snap disk below a heat transfer plate and there to hold loosely by means of four hooks which engage over the edge of the bimetallic snap disk.

From the DE 10 2011 119 633 B1 is a temperature-dependent switch with a temperature-dependent switching mechanism receiving housing known. The temperature-dependent switching mechanism has a bimetal snap-action disc and a spring snap-action disc, both of which are captively held on a contact plate which cooperates with two stationary mating contacts on the inside of the housing cover. The arranged above the bimetallic snap disk spring snap-action disc is guided with its edge between an inner shoulder of the housing base and a ring arranged between the shoulder and the housing cover.

WO2010 / 139781 discloses a temperature-dependent switching mechanism according to the preamble of claim 1.

Against this background, the present invention has the object, the known switching mechanism in such a way that simplifies the assembly of the thus equipped temperature-dependent switch, in particular, the switch itself can be constructed mechanically simpler and cheaper.

In the above-mentioned temperature-dependent rear derailleur, this object is achieved in that the switching mechanism has an annular frame in which the bimetallic snap disk and possibly provided spring snap-action disc are held captive.

The inventors of the present application have in fact recognized that a temperature-dependent switching mechanism can be constructed, as it were, like a pushbutton, ie with an annular frame in which the bimetallic snap disk or both snap disks are held captive, which preferably takes place over their edges in order to snap it over to allow the domes in their respective centers.

With this design, which at first glance is a structurally more complex design, there are many advantages that ultimately lead to the new one Derailleur equipped temperature-dependent switch can be easily assembled and mounted.

The or each snap-action disc is captively arranged in the annular frame, so that the switching mechanism can be pre-produced and tested without the complete assembly of a temperature-dependent switch itself is required.

Through the annular frame, the or each snap-action disc is mechanically protected from damage, so that the completed and tested new derailleur can be stored as bulk material, which is the prerequisite for a subsequent automatic assembly of equipped with the new rear derailleur switch.

Because the or each snap-action disc is now arranged in the annular frame, the lower parts of a temperature-dependent switch equipped therewith can be made simpler, rotating parts, for example made of brass, are no longer necessary.

Preferably, the lower part of a temperature-dependent switch, which is designed with the new rear derailleur, therefore, an inexpensive deep-drawn part made of steel.

The mechanical protection of the or each snap-action by the annular frame also provides more freedom in shaping the housing of the equipped with the new rear derailleur temperature-dependent switch, since the snap discs are no longer aligned in the housing but with the annular frame and support.

The new rear derailleur can be inserted into a two-part housing as well as into a one-piece, so-called slide-in housing.

While it is also provided according to the invention that the new derailleur has only a bimetallic snap disk, which produces both the closing pressure and the operating current leads, it is particularly preferred if the new derailleur has a bimetallic snap disk and a spring snap disk, said both snap disc are arranged one above the other.

The annular frame does not necessarily have to be circular, it may also be oval, rectangular, square or oblong rounded. Corresponding shapes then also has the or each snap disc. This is particularly advantageous if the new rear derailleur is to be used in a plug-in housing.

On the other hand, if the new switching mechanism is inserted into a conventional temperature-dependent switch with a two-part housing comprising the lower part and the cover part, then the annular frame and the one or both snap-action disks are preferably of circular design.

The movable contact member may be either a contact bridge, on which two contact parts are arranged, which are electrically connected to each other via the contact bridge and each interact with a stationary counter contact, or a contact part, which cooperates with a stationary counter-contact, wherein the operating current then via a Snap disk flows.

In this case, the contact member may further be both a separate component, as well as be formed on the bimetal schnapps slice and / or the spring snap-action disc itself.

In a equipped with the new rear derailleur temperature-dependent switch, the annular frame can also compensate for height and curvature tolerances in the snap discs, so that no further action must be taken.

The frame can be designed so that its installation height can be readjusted by suitable deformation of the edge of the frame to compensate for installation tolerances.

Such subsequent adjustability has hitherto not been known in the prior art and technically also not possible.

The problem underlying the invention is completely solved in this way.

It is preferred if the annular frame has an upper annular surface, and preferably has a lower annular surface, wherein more preferably the upper and lower annular surfaces are arranged parallel to each other and connected by a transverse to the annular surfaces, circumferential cylindrical surface.

These measures are structurally advantageous, they allow a clamping of the annular frame not only in the mounted temperature-dependent switch but also already for testing outside a switch, without the risk that the recorded in the frame snap discs are damaged.

About the upper and / or lower annular surface and possibly the cylindrical surface can be made a contacting of the annular frame, so for example. The electrical contact to a consisting of conductive material lower part or a test device.

It is preferred if a conical transition surface is arranged between the cylindrical surface and the lower annular surface.

This conical transition surface allows the insertion of the new rear derailleur in deep-drawn parts, in which the transition between the ground and the circumferential wall is not formed at right angles. So here is an advantage that structurally simple and inexpensive parts can be used for the equipped with the new rear derailleur switch.

The movable contact member is preferably formed as a movable contact part, which is arranged between the bimetallic snap disk and spring snap disk.

During assembly, a snap-action disc is then firstly inserted into the annular frame, then the movable contact part is placed on the snap-action disc, and then the other snap-action disc is inserted into the frame, because the lower snap-action disc is already held in the frame during insertion of the movable contact part. makes the installation of the new rear derailleur very easy.

On the ring-shaped frame, the snap-on disc can be kept simpler and more reliable than a loose snap-action disc, eliminating the risk that the snap-action disc will already be damaged during this assembly step.

In general, it is preferred if the bimetallic snap disk is fixed captive with play on the movable contact member and preferably the spring snap disc is captively fixed to the movable contact member.

In this measure, it is advantageous that the three active components of the new switching mechanism, so the bimetallic snap disk, the spring snap disc and the movable contact member need not be inserted sequentially in the annular frame, which is technically quite possible, but as a unit in the framework can be introduced. This facilitates the assembly of the new rear derailleur.

In general, it is further preferred if inside a lower circumferential shoulder is arranged in the frame, on which the bimetallic snap disk is supported at the transition in its low-temperature position with its edge, preferably inside the frame an upper circumferential shoulder is arranged, on which the spring snap-action disc is fixed over its edge.

Here it is advantageous that the two shoulders used for the switching function are arranged inside in the annular frame, so that neither the edge of the bimetallic snap disk nor the edge of the spring snap-action disc protrudes upwards or downwards over the frame, if the rear derailleur, for example is tested outside a switch and is exposed to both high and low temperatures.

In the low-temperature position, the spring snap-action disc is supported by its edge on the upper circumferential shoulder and pushes the movable contact member upwards, ie in the assembled switch against the or each stationary contact part. The bimetallic snap disk is in this closed position without force below the spring snap disk.

When switching in the high-temperature position, the bimetallic snap disk presses with its edge from below against the spring snap-action disc and thus opens the switch.

When switching back to the low temperature position, the bimetallic snap disk first snaps around, whereby it is now supported with its edge on the lower shoulder because of the further lying at the lower annular surface movable contact member while the center of the spring-snap disc and with this the movable contact member pushes upwards, whereby the spring snap-action disc is pressed back into its first geometrically stable position in which it holds the switch electrically closed.

After this switching, the bimetallic snap disk is again free of forces in the frame.

In the context of the present invention, the term "top" or "above" is understood to mean a direction from the bimetallic snap disk to the stationary contact member, with a direction "downward" or "below" from the spring snap disk to the bimetal below it Snapping disk is understood.

In contrast to the rear derailleur from the above-mentioned DE 43 45 350 C2 According to the invention, the bimetallic snap-action disc is below the spring snap-action disc.

It is preferred if the upper shoulder is arranged in an inner circumferential groove in the frame in which the spring snap-action disc is fixed with its edge, wherein preferably the edge of the spring snap-action disc is engaged in the groove or alternatively by a the laying of the edge of the spring snap disc on the upper shoulder embossed projection is fixed.

This measure is on the one hand for the function of advantage, because the edge of the spring-snap disc is fixed up and down, but can expand radially outward in the groove, so that the spring-snap disc when jumping from one to the other geometrically stable position is not mechanically stressed.

However, these measures are also in terms of the assembly of the switching mechanism advantageous because namely the spring snap-action disc is locked in the one case only by pressing down into the groove.

In the other case, first the three active components are inserted individually or as an interconnected, for example via the movable contact member unit in the annular frame and then coined a projection on the edge of the spring snap-action disc.

By over-embossing of the projection while the installation height of the annular frame can be adjusted at the same time.

In a further development, it is preferred if the derailleur has a flat, blechartiges power transmission member which is connected to the contact member designed as a movable contact part, wherein the current transmitting member is preferably connected to the annular frame.

The connection to the annular frame can on the one hand take place in that the current transfer member rests with its edge on the lower shoulder, that is arranged on the side of the bimetallic snap disk.

The current transmission member may also be on the side of the spring snap-action disc and be arranged with its edge in the circumferential groove.

In these measures, it is advantageous that when opening and / or closing a equipped with the new switching mechanism temperature-dependent switch forming arcs do not lead to the damage, as is done without this power transmission element. For this reason, the power transmission member in terms of function is an arc screen, as in the not pre-published DE 10 2013 101 393 is described in detail.

Especially at the end of the life of a temperature-dependent rear derailleur namely migrates from the base of the arc of the movable contact part on the spring part, which eventually because of its extremely small thickness causes holes are burned in the spring part or larger amounts of metal oxide are deposited there.

Even a partial coverage of the top of the spring member results contrary to expectations, a protection against spattering sparks and metal oxides as well as from direct contact with the arc root.

Surprisingly, this extremely simple measure leads to the fact that the life of the new switch is extended with the same construction and the same current strength, although it has even been found that at the same time increase the maximum current rating and lifetime of a switch equipped with the new derailleur.

When the current transmitting member is connected to both the movable contact member and the annular frame, it provides a permanent electrical connection between the movable contact member and the annular frame, so it is connected in electrically conductive annular frame to the spring snap disc, so to speak electrically in parallel and allows a higher strength of the flowing operating current.

Alternatively, it is also possible that the current transmitting member is arranged with its edge above the upper annular surface or below the lower annular surface.

This means that the power transmission member is not completely within the annular frame. The edge of the current transmission member may be fastened on the upper or lower annular surface, for example by spot welding.

When mounting a equipped with the new rear derailleur temperature-dependent switch, the power transmission member is clamped with its edge between the lower ring surface and the bottom of the housing base or between the upper annular surface and the inside of the lid.

If the edge of the current transmitting member is not attached to the upper or lower ring surface, the electrical contacting of the edge of the current transmitting member takes place only during the assembly of the equipped with the new rear derailleur switch.

In general, it is preferred if the annular frame comprises electrically conductive material or electrically insulating material.

When the annular frame itself is electrically conductive, the operating current of the device to be protected flows through the frame itself and through the spring snap-action disc or the bimetallic snap-action disc, if the spring snap-action disc is dispensed with in a simple switch, and by the latter movable contact part.

If, on the other hand, the frame is made of electrically insulating material, then the current is transmitted through the current transmission member, which is contacted as described above, or through the contact member designed as a contact bridge with two contact parts.

The current transfer member can then represent a small series resistance, so that it provides as a heating resistor for a current-dependent switching function. This is particularly useful when the power transmission member lies with its edge below the lower ring surface, because it is then in the immediate vicinity of the bimetallic snap disk, which is then effectively heated by the developed ohmic heat.

Furthermore, it is then advantageous that the spring snap-action disc, which ensures the contact pressure between the movable contact part and the stationary mating contact when the switch is closed, is not heated up so much, which increases its service life.

When the frame is made of electrically insulating material, the operating current flows through the movable contact part and the current transfer member, the spring snap-action disc is always de-energized, which also increases their life.

It is further preferred if the annular frame comprises electrical resistance material, preferably at least one resistance layer.

The frame itself may, for example. From PTC material or other suitable material, where it depends on the interconnection and arrangement can serve as a self-holding resistor and / or as a series resistor for current-dependent switching.

Even if the contact member is designed as a contact plate with two contact parts, a frame of resistance material can serve as a self-holding resistor.

It is also possible to provide the annular frame with a resistance layer which is arranged on the upper annular surface, the lower annular surface and / or the cylindrical outer wall and serves as a self-holding resistor or series resistance for current-dependent switching.

Alternatively or additionally, the current transmission element can also be designed with a corresponding resistance value, so that it provides for current-dependent switching.

Depending on the material of the annular frame, the rear derailleur can also serve to stabilize the housing, wherein the switching mechanism can also be used directly in a receiving opening in a device, as this in principle from the DE 195 06 342 C1 is known.

Because all functionally relevant tests can already be made on the rear derailleur, which has not yet been installed in a temperature-dependent switch, the scrap costs are also considerably reduced.

Against this background, the present invention also relates to a temperature-dependent switch with a pot-like lower part, which is closed by a cover part, and with two external terminals, wherein in the switch, the new temperature-dependent switching mechanism is arranged, which, depending on its temperature, an electrically conductive connection between the two external connections manufactures.

Furthermore, the present invention relates to a temperature-dependent switch with a plug-in housing, on which two external connections are provided, wherein in the plug-in housing, the new temperature-dependent switching mechanism is used, which produces an electrically conductive connection between the two external connections as a function of its temperature.

Further advantages will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Fig. 1

ein erstes Ausführungsbeispiel eines Schaltwerkes mit ringförmigen Rahmen, in schematischer, geschnittener Darstellung;

Fig. 2

ein weiteres Ausführungsbeispiel des neuen Schaltwerkes in einer Darstellung wie Fig. 1;

Fig. 3

in einer schematischen geschnittenen Seitenansicht einen temperaturabhängigen Schalter, der mit dem Schaltwerk aus Fig. 2 ausgerüstet ist;

Fig. 4

eine Draufsicht auf das Schaltwerk aus Fig. 1, jedoch mit zusätzlichem Stromübertragungsglied;

Fig. 5

eine schematische Draufsicht auf das Stromübertragungsglied aus Fig. 2;

Fig. 6

in einer schematischen geschnittenen Seitenansicht einen Einschubgehäuse, das mit dem Schaltwerk aus Fig. 1 ausgerüstet ist;

Fig. 7

ein schematisches Funktionsbild des Schalters aus Fig. 3;

Fig. 8

eine Darstellung wie in Fig. 7, jedoch mit einem Selbsthaltwiderstand;

Fig. 9

eine Darstellung wie in Fig. 7, jedoch mit einem Reihenwiderstand für stromabhängiges Schalten;

Fig. 10

eine Darstellung wie in Fig. 8, jedoch mit Reihenwiderstand für stromabhängiges Schalten und ohne Stromübertragungsglied; und

Fig. 11

eine Darstellung wie in Fig. 10, jedoch ohne Reihenwiderstand aber mit Selbsthaltewiderstand.

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

Fig. 1

a first embodiment of a switching mechanism with annular frame, in a schematic, sectional representation;

Fig. 2

another embodiment of the new switching mechanism in a representation like Fig. 1 ;

Fig. 3

in a schematic sectional side view of a temperature-dependent switch, with the rear derailleur Fig. 2 is equipped;

Fig. 4

a plan view of the rear derailleur Fig. 1 but with additional power transmission element;

Fig. 5

a schematic plan view of the current transmission member Fig. 2 ;

Fig. 6

in a schematic sectional side view of a plug-in housing, with the rear derailleur Fig. 1 is equipped;

Fig. 7

a schematic functional picture of the switch Fig. 3 ;

Fig. 8

a representation like in Fig. 7 but with a self-holding resistance;

Fig. 9

a representation like in Fig. 7 but with a series resistance for current-dependent switching;

Fig. 10

a representation like in Fig. 8 but with series resistance for current dependent switching and without current transfer element; and

Fig. 11

a representation like in Fig. 10 , but without series resistance but with self-holding resistance.

In Fig. 1 is designated by a temperature-dependent switching mechanism 10, which has a circular bimetallic snap disk 11 and arranged above the bimetallic snap disk 11 circular spring snap-action disc 12. The bimetallic snap disk 11 and the spring snap disk 12 are arranged captive on a movable contact part 14.

The bimetallic snap disk 11 and the spring snap-action disc 12 are held captive in a likewise annular annular frame 15 which has an upper annular surface 16 and a lower annular surface 17 parallel thereto, which lies radially further inward than the upper annular surface 16 Ring surface 16 and the lower annular surface 17 are interconnected via a transverse to the annular surfaces 16, 17 extending cylindrical surface 18 and a conical transition surface 19 which extends inclined between the cylindrical surface 18 and the lower annular surface 17.

While the movable contact member 14 projects upwardly above the upper annular surface 16, the lower annular surface 17 is downwardly over the movable Contact part 14 and in particular on the bimetallic snap disk 11 and the spring snap disk 12 before, so that when opening the rear derailleur 10, the movable contact member 14 does not project down over the lower annular surface 17, so that no special measures must be taken to a To prevent contact between the movable contact part 14 and an inner bottom of a switch equipped with the switch when the switch opens.

The bimetallic snap disk 11 rests with its edge 21 loosely on an inner, in the frame 15 encircling, annular lower shoulder 22.

The spring snap-action disc 12 lies with its edge 23 on an inner in the frame 15 annular circumferential, upper shoulder 24 which is formed in a groove 25 which is formed by the shoulder 24 and the edge 23 cross-projection 26.

In this way, the spring snap-action disc 12 is held captive in the groove 25 and thus in the frame 15 via its edge 23.

At its inner portion 27, the spring snap-action disc sits captive but with play in a circumferential groove 28 which is arranged on the movable contact part 14.

Between the spring snap-action disc 12 and a circumferential shoulder 29 on the movable contact part, the bimetallic snap-action disc 11 is held captive but with play.

The rear derailleur 10 can be tested before mounting in a switch and store as bulk material, because the edges 21, 23 of the snap discs 11, 12 are protected by the frame 15 and the spring snap-action disc 12 can be contacted via the frame 15.

As mentioned above, the rear derailleur 10 may also have only one snap-action disc, namely the bimetal snap-action disc 11, which is then arranged in the frame 15, as it is in Fig. 1 for the spring snap-action disc 12 is shown. The bimetallic snap disk 11 is then arranged with its edge 21 in the circumferential groove 25 and fixed so captive in the frame 15. Furthermore, the bimetallic snap disk 11 then carries the movable contact part 14, on which it is arranged with its inner portion captive but with play in the circumferential groove 28.

This in Fig. 2 shown temperature-dependent rear derailleur 10 'is basically the same structure as the rear derailleur 10 Fig. 1 However, it is additionally provided with a sheet-like current transmission member 31 which is welded at its center 32 to the movable contact part 14.

With its edge 33, the current transfer member 31 protrudes beyond the lower annular surface 17. The edge 33 may be fixedly connected to the annular surface 17 by spot welding. Also, the rear derailleur 10 'can be tested before the shoring.

In Fig. 3 a temperature-dependent switch 35 is shown, which has a pot-like lower part 36 which is closed by a plate-like cover part 37.

In the lower part 36, the rear derailleur 10 'is made Fig. 2 inserted so that the frame 15 with its cylindrical surface 18 inside in contact with a peripheral wall 38 of the lower part 36 and the peripheral wall 38 so stabilized.

By inserting the rear derailleur 10 'in the lower part 36, the power transmission member 31 is clamped with its edge 33 between the lower annular surface 17 and an inner bottom 39 of the lower part 36.

The lower part 36 is a deep-drawn part, so that the transition between wall 38 and bottom 39 is not formed exactly, in particular not at right angles. Because the frame 15 has the conical transition surface 19, it can still be positioned exactly in the lower part 36.

On the upper annular surface 16 of the frame 15 is an insulating film 41 which extends laterally between the cover member 37 and the wall 38 upwardly and is then pressed from above onto the cover member 37, to which the wall 38 was crimped at its upper edge 42 ,

In this way, the edge 42 presses on the cover part 37 and this on the insulating film 41 on the upper annular surface 16, whereby the frame 15 and thus the switching mechanism 10 'is fixedly mounted in the temperature-dependent switch 35 and at the same time the electrical contact between the inner bottom 39 of the lower part 36 and the edge 33 of the power transmission member 31 is made.

The annular frame 15 can be made here both of electrically conductive material and of electrically insulating material.

On an inner side 43 of the cover part 37, a stationary mating contact 44 is arranged, which in the in Fig. 3 shown closed state of the switch 35 is in contact with the movable contact part 14.

In the in Fig. 3 shown switching state is the bimetallic snap disk 11 forces in the rear derailleur 10 ', while the spring snap disk 12 is supported with its edge 23 in the groove 25 and the movable contact member 14 presses against the stationary counter contact 44. In this way, the electrical circuit between the stationary mating contact 44 and the existing here of electrically conductive material lower part 36 is closed, wherein the operating current of a device to be protected via the current transfer member 31 and possibly also via the spring snap disk 12 flows.

The switch 35 has two outer terminals, which are formed by the outer bottom 36 'of the lower part 36 and the outer surface 44' of the stationary mating contact 44. When switch 35 is closed, the two outer terminals 36 'and 44' are electrically conductively connected to one another.

If the temperature of the switch 35 increases beyond the switching temperature of the bimetallic snap disk 11, so this moves with its edge 21 in Fig. 3 upwards and presses from below against the spring snap-action disc 12. It pulls the movable contact member 14 of the stationary counter-contact 44 away down until the spring snap-action disc 12 of her in Fig. 3 shown a stable geometric configuration in its other stable geometric configuration umspringt in which it keeps the movable contact part 14 at a distance to the stationary mating contact 44.

When the temperature of the switch 35 lowers again, so first jumps the bimetallic snap disk back in their in Fig. 3 shown configuration. Because the movable contact member 14 is now further down in the direction of the bottom 39, the bimetallic snap disk 11 comes with its edge 21 in abutment with the peripheral shoulder 22 and presses upon further change in shape over the center of the spring snap disk 12, the movable contact part 14th to the stationary counter contact 44 to. In this case, the spring snap-action disc 12 is bent in its center up until they return to their in Fig. 3 shown stable geometric configuration in which it presses the movable contact member 14 against the stationary mating contact 44.

In this switching state, the bimetallic snap disk 11 is again stored without force.

If the annular frame 15 is made of an electrically insulating material, can be dispensed with the insert of the insulating film 41. The operating current then flows when the switch 35 is closed only by the current transfer member 31, which heats up depending on their contact resistance.

Because the current transmitting member 31 is located on the side of the bimetallic snap disk 11, the evolving ohmic heat leads to rapid heating of the bimetallic snap disk 11, which ensures an accurate response of the switch 35 to an excessive operating current of a device to be protected.

Because the spring snap-action disc 12 remains de-energized in this design, it shows a long life.

If the annular frame 15 consists of an electrically conductive material or is covered with a layer of an electrically conductive material, it represents a parallel resistor which is parallel to the switching mechanism 10 'both with the electrically conductive cover part 37 and with the electrically conductive lower part 36 is connected, although here is dispensed with the insert of the insulating film 41.

As long as the rear derailleur is closed, the self-holding resistor thus formed is short-circuited by the highly electrically conductive current transmitting member 31. However, when the switch 35 opens, the self-holding resistor formed by the annular frame 15 is now in series between the stationary mating contact 44 and the base 36, so that a residual current flows through the switch 35, which keeps the switching mechanism open until the power supply of is switched off to be protected electrical device.

In addition, the power transmission member 31 can provide as a heating resistor for a current-dependent switching.

In a modification may be at the switch off Fig. 3 also the rear derailleur 10 Fig. 1 are used, so that the current flow then takes place exclusively by the spring snap-action disc 12.

Also in this case, the annular frame 15 may consist of electrically conductive material or, for example, on the cylindrical surface 18 or the lower annular surface 17 have an electrically conductive layer.

In this way, a series resistor would then be formed, which is connected in series with the spring snap disk 12 and provides in the manner described above for a current-dependent switching of the switch 35.

Further, the frame 15 may be so covered with resistive material that it acts as a self-holding resistor.

The height of the frame 15 between the upper and lower annular surface 16, 17 may be chosen so that the movable contact member 14 does not come into contact with the bottom 39 when the switch 35 is open.

While in Fig. 2 a current transfer member 31 is shown, which projects down over the lower annular surface 17, shows the Fig. 4 a plan view of the rear derailleur 10 Fig. 1 , which is now provided with a current transmitting member 45, which is connected on the one hand to the movable contact part 14 and on the other hand to the upper annular surface 16, under which it extends.

Alternatively, the current transfer member 45 could also extend over the upper annular surface 16, so that it would then be clamped in a switch 35 between the upper annular surface and the inner side 43 of the cover part 37.

In the rear derailleur 10 off Fig. 4 However, the power transmission member 45 is permanently connected to both the movable contact member 14 and the frame 15, so that it serves not only the power transmission but also as an arc screen.

The current transmitting member 45 may also extend only to one side away from the movable contact member 14 so as to leave free a large area of the top of the spring snap-action disc.

In Fig. 5 is an embodiment of the current transfer member 31 in a schematic plan view Fig. 2 shown. The current transmitting member 31 is formed as a circular disc in which curved, spiral and radially outwardly extending slots 46, 47 are located. These slots 46, 47 reduce the spring action of the current transfer member 31, so that it does not counteract when switching the spring force of the bimetallic snap disk and the spring snap-action disc 12.

In Fig. 6 a plug-in housing 50 is shown with walls 51 of electrically insulating material which limit an insertion opening 52. In the insertion opening 52, the rear derailleur 10 is made Fig. 1 inserted. In this case, the frame 15 comes into contact with a bottom electrode 53 and the movable contact part 14 in abutment with a cover electrode 54th

Bottom electrode 53 and cover electrode 54 are formed on the inside of the walls 51 and connected in a manner not shown with external terminals 55 and 56, respectively.

The plug-in housing 50 can be used as a temperature-dependent switch, in which the switching mechanism 10 between the external terminals 56, 57 produces or opens an electrical connection depending on temperature.

It is also possible that the insertion housing 50 is part of a device to be protected, in which a pocket forms the insertion opening 52. The external connections can then lead to windings or components between which the switching mechanism 10 establishes or opens a temperature-dependent electrical connection.

In Fig. 7 is a schematic functional picture of the switch 35 Fig. 3 shown. The switch 35 is closed, so that the operating current of the electrical appliance to be protected by the cover part 35 and the movable contact part 14, from this by the spring snap-action disc 12 and in parallel by the current transfer member 31, and then by the frame 15 and the lower part 36th flows.

Consequently, when the frame is made of electrically insulating material, the operating current flows only through the lid part 35 and the movable contact part 14, from the latter through the current transmitting member 31 and then through the lower part 36.

On the insulating film 41 can then be dispensed with.

At the switch 35 'off Fig. 8 the insulating film 41 is replaced by a lying between the cover part 37 and frame 15 resistance layer 57. The frame 15 is made of electrically conductive material. When closed, the current flows as in the switch 35 Fig. 7 , However, if the switch 35 'is opened, a residual current flows through cover part 37, resistance layer 57, frame 15 and lower part 36. In the resistance layer 57, a sufficient ohmic heat develops, which prevents the bimetallic snap disk 11 from cooling below its return temperature. so that the switch 35 'remains open.

Instead of a resistive layer 57, the frame 15 may also itself entirely or partially consist of resistance material in order to realize the self-holding function.

In Fig. 9 the switch 35 is off Fig. 7 modified so that the power transmission member 31 is formed as a series resistor. The frame 15 is electrically insulating, so that it is possible to dispense with the insulating film 41.

In the closed state of the switch 35 ', the operating current flows through cover part 37, movable contact member 14 and current transfer member 31 in the lower part 36. In this case, the current transmission member 31 heated by the integrated series resistance at high current flow so far that the developed ohmic heat the switch 35 "already opens before the heat developed by the device to be protected heats it up to the point where it opens.

In Fig. 10 the switch 35 is off Fig. 7 shown, but without Stromübertragungsglied 31. For the frame 15 is made of resistance material, so that it acts as a series resistor for current-dependent switching.

In the closed state of the switch 35 "'the operating current flows through cover part 37, movable contact part 14, spring snap-action disc 12 and frame 15 in the lower part 36. In this case heats up the frame 15 by the integrated series resistance at high current flow so far on that the developed ohmic heat the Switch 35 "already opens before the heat developed by the device to be protected heats it up so far that it opens.

In Fig. 11 is the switch 35 '"off Fig. 10 shown, wherein the frame 15 is electrically conductive here. Instead of the insulating film 41 is as in the switch 35 'off Fig. 8 a resistance layer 57 is provided.

In the closed state of the switch 35 ^IV , the operating current flows through cover part 37, movable contact part 14, spring snap-action disc 12 and frame 15 into the lower part 36.

When the switch 35 opens ^IV , a residual current flows through the cover part 37, resistance layer 57, frame 15 and lower part 36. In the resistance layer 57, sufficient ohmic heat develops, which prevents cooling of the bimetallic snap disk 11 below its return temperature that the switch 35 'remains open.

Instead of a resistive layer 57, the frame 15 here as well may consist entirely or partially of resistance material in order to realize the self-holding function.

In addition, the switch 35 ^{IV may} still have a resistive layer 58 between the frame 15 and lower part 36, which provides series resistance for current-dependent switching, because he is 35 ^IV closed circuit in the circuit of the operating current and heats up at high current flow so far that the Switch 35 ^IV opens.

The resistance of the resistive layer 57 is much greater than that of the resistive layer 58.

Claims (26)

1. Temperature-dependent switching mechanism comprising a bimetal snap-action disc (11) and a movable contact member (14),
   characterized in that the switching mechanism (10, 10') comprises an annular frame (15), in which the bimetal snap-action disc (11) is captively held.
2. Switching mechanism according to Claim 1, characterized in that is comprises a spring snap-action disc (12) captively held in said annular frame (15).
3. Switching mechanism according to Claim 1 or 2, characterized in that the annular frame (15) has an upper ring surface (16).
4. Switching mechanism according to anyone of Claims 1 to 3, characterized in that the annular frame (15) has a lower ring surface (17).
5. Switching mechanism according to Claim 3 and 4, characterized in that the upper ring surface (16) and the lower ring surface (17) are arranged parallel to one another and are interconnected by a peripheral cylinder surface (18) running transversely to the ring surfaces (16, 17).
6. Switching mechanism according to Claim 5, characterized in that a conical transition surface (19) is arranged between the cylinder surface (18) and the lower ring surface (17).
7. Switching mechanism according to anyone of Claims 2 to 6, characterized in that the contact member is a movable contact part, which is arranged between the bimetal snap-action disc (11) and the spring snap-action disc (12).
8. Switching mechanism according to anyone of Claims 1 to 7, characterized in that the bimetal snap-action disc (11) is fixed captively with play to the movable contact member (14).
9. Switching mechanism according to anyone of Claims 2 to 8, characterized in that the spring snap-action disc (12) is fixed captively to the movable contact member (14).
10. Switching mechanism according to anyone of Claims 2 to 9, characterized in that a lower peripheral shoulder (22) is arranged internally in the frame (15), on which shoulder the bimetal snap-action disc (11) is supported via its rim (21) during the transition into its low-temperature position.
11. Switching mechanism according to anyone of Claims 2 to 10, characterized in that an upper peripheral shoulder (24) is arranged inwardly in the frame, on which shoulder the spring snap-action disc (12) is fixed via its edge (23).
12. Switching mechanism according to Claim 11, characterized in that the upper shoulder (24) is arranged in a groove (25) running peripherally internally in the frame (15), in which groove the spring snap-action disc (12) is fixed via its edge (23).
13. Switching mechanism according to Claim 12, characterized in that the rim (23) of the spring snap-action disc (12) is latched into the groove (25).
14. Switching mechanism according to Claim 11, characterized in that the rim (23) of the spring snap-action disc (12) is fixed by a protrusion (26) shaped once the rim (23) of the spring snap-action disc (12) has been placed on the upper shoulder (24).
15. Switching mechanism according to anyone of Claims 1 or 3 to 6, characterized in that a groove running peripherally internally in the frame (15) is provided, in which groove the bimetall snap-action disc (11) is fixed via its rim (21).
16. Switching mechanism according to anyone of Claims 1 to 15, characterized in that it comprises a current transfer member (31), which is connected to the contact member formed as a movable contact part (14).
17. Switching mechanism according to Claim 16, characterized in that the current transfer member (31) is connected to the annular frame (15).
18. Switching mechanism according to Claim 16 or 17, characterized in that the current transfer member (31) is arranged between the upper and the lower ring surface (16, 17).
19. Switching mechanism according to Claim 16 or 17, characterized in that the current transfer member (31) is arranged with its rim (33) above the upper ring surface (16).
20. Switching mechanism according to Claim 16 or 17, characterized in that the current transfer member (31) is arranged with its rim (33) below the lower ring surface (17).
21. Switching mechanism according to anyone of Claims 1 to 20, characterized in that the annular frame (15) comprises electrically conductive material.
22. Switching mechanism according to anyone of Claims 1 to 20, characterized in that the annular frame (15) comprises electrically insulating material.
23. Switching mechanism according to anyone of Claims 1 to 22, characterized in that the annular frame (15) comprises electrical resistance material, preferably at least one resistive layer (57, 58).
24. Temperature-dependent switch comprising a pot-like lower part (36), which is closed by a cover part (37), and comprising two outer connections (36', 44'), wherein the temperature-dependent switching mechanism (10, 10') according to anyone of Claims 1 to 23 is arranged in the switch (35), and said temperature-dependent switching mechanism, depending on the temperature thereof, produces an electrically conductive connection between the two outer connections (36', 44').
25. Switch according to Claim 24, characterized in that the lower part (36) is a deep-drawn part.
26. Temperature-dependent switch comprising an slip-in housing (50), on which two outer connections (56, 57) are provided, wherein the temperature-dependent switching mechanism (10, 10') according to anyone of Claims 1 to 23 is inserted into the slip-in housing (50), and said temperature dependent switching mechanism, depending on the temperature thereof, produces an electrically conductive connection between the two outer connections (56, 57).

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