EP3619732B1 - Snap-action switch having a current-conducting snap-action spring, method for producing such a snap-action switch, and overload relay and tripping indicator having such a snap-action switch - Google Patents

Description

The invention relates to a snap switch with a current-carrying spring according to claim 2, a method for producing such a snap switch according to claim 1 and an overload relay and a trip detector with such a snap switch according to claims 9 and 10, respectively.

The use of such a snap switch with a current-carrying spring in an overload relay is from the German published application DE 3840064 A1 known and in it Fig. 1 shown. The springs used in such overload relays are subject to requirements for high mechanical and thermal long-term stability and good electrical conductivity. Materials made from copper-beryllium alloys can be used to meet these requirements. However, the alloy component beryllium is considered harmful to health. Therefore, it should be avoided if possible. In addition, its use could be restricted or banned entirely for precisely this reason in the future.

As an alternative to the current-carrying spring, solutions are known that decouple the functions of long-term mechanical stability and good electrical conductivity. For example, classic steel springs are paired with a tilting bearing mechanism and movable switching contacts that carry the current, see for example those from the European patent application EP 2345056 A1 known solution.

From the British disclosure document GB 669969 A A spring for an electrical snap switch is known which has a spring steel core plated with a thin layer of copper. The thickness of the copper plating is chosen such that it has a significantly higher electrical conductivity than the spring steel core, but does not significantly affect its springiness. However, the disruptive influence of the plated copper can cause increased production variability.

Finally, from the German disclosure document DE 3530221 A1 a miniature switch is known which has a movable spring plate which is plated in a contact area with fixed contacts with a noble metal such as silver, gold or an alloy thereof in order to increase the electrical conductivity at the corresponding interfaces and at the same time a moving one on the movable spring plate To set contact with extremely reduced thickness. The US patent also discloses US5,121,095 a thermal motor protection switch with a bimetal provided with silver plating in a contact area to improve contactability. The German disclosure document DE 19537418 A1 discloses a thermally controlled electrical switching device having a temperature controller comprising a snap switch provided with a fixed contact and a movable contact connected to a metal snap spring, a bimetal element influencing the movement of the movable contact. Edge parts of the snap-action spring can be coated with an electrically highly conductive layer.

The object of the present invention is to improve a snap switch with a current-carrying spring.

This task is solved by the subject matter of the independent claims. Further refinements of the invention are the subject of the dependent claims.

An idea underlying the present invention is to produce the current-carrying spring of a spring switch from a multi-layer plated material, and to displace the plating at at least one adjustment point of the spring, and to deform the spring during assembly in the spring switch, so that by means of precise shaping A defined jump movement is made possible during the assembly process and, in particular, the jump switch is adjusted accordingly. The plating is provided over as large an area as possible and in particular is only displaced at the adjustment point(s), so that the best possible electrical conductivity for a current flow via the spring and one that is as precisely defined as possible Jumping movement can be ensured by good deformability at the adjustment point(s), in contrast to plating only at a contact area to improve the contact ability. Displacing a plating at the adjustment point(s) where the spring is deformed during assembly has proven to be a solution for achieving the two effects of good electrical conductivity and one that can be defined as precisely as possible, which cannot be combined or can only be combined with great technical effort Jumping movement highlighted during assembly. The plating in particular has one or more metal layers, which preferably have better electrical conductivity than a base material or the base layer on which the plating is applied. For example, the plating can have a layer made of a non-ferrous metal and/or a layer made of a noble metal, while the base material or the base layer can be made of a spring material such as an elastic metal, in particular a spring steel. Depending on the choice of spring material for the spring, it can have magnetic or non-magnetic properties and can be designed for frequent bending changes. From the from the DE 3840064 A1 and GB 669969A Known springs, the present invention differs in the shape of the spring formed from a multi-layer material, in which the plating with the more conductive material is partially or completely at the adjustment point (s) of the spring, i.e. in particular at bending and / or buckling points is displaced so that the core of the spring, the actual spring material, can receive the desired deformation. This ensures that the spring material can be deformed in a more defined manner and that springs manufactured in this way have less production variation. In order to minimize the disruptive influence of the spring properties of the plated metal, the carrier of the leaf spring forming the spring can be individually slightly deformed in a partially assembled spring switch in order to avoid manufacturing tolerances of the spring in the operatively connected functional chain of a device in which the spring switch is installed and which has several parts and / or assemblies may have to compensate.

One embodiment of the invention relates to a method of making a snap switch according to the invention and as described herein, wherein: Jump switch has a current-carrying spring which can be brought into two rest positions by mechanical actuation, with the following steps: producing the spring from a multi-layer plated material, fixing the spring at least one end in the spring switch, and deforming the spring at the adjustment points at the Mounting in the spring switch to adjust the spring switch, with partial or complete displacement of the plating at adjustment points of the spring either during the deformation step or before the deformation step. A further embodiment of the invention relates to a snap switch which has a current-carrying spring which can be brought into two rest positions by mechanical actuation and is made from a multi-layer plated material, the plating being partially or completely displaced at adjustment points of the spring, and wherein the Jump switch is adjusted in that the spring has been deformed at the adjustment points during assembly in the jump switch. The jump switch is produced using the method according to the invention.

Before assembly in the snap switch, the current-carrying spring can already be pre-bent, which can, for example, make assembly of the snap switch easier.

According to the invention, the plating has at least one layer made of a non-ferrous metal and/or one layer made of a noble metal.

In the simplest case, the plating can therefore be designed as a single layer, for example a plating with a layer of non-ferrous metal such as copper, or a plating with a layer of precious metal such as silver, or it can be designed in multiple layers, for example with a first layer of non-ferrous metal and a second layer of precious metal . A multi-layer plating can be chosen, for example, to achieve a certain electrical conductivity of the spring.

The non-ferrous metal can in particular be copper and the current-carrying spring can in particular be made from a spring steel strip that is copper-plated on both sides by punching out and possibly pre-bending.

When assembling the spring switch, for example, the spring switch may have been fixed at one, two or three ends either under tension or fixed without tension and tension in the spring spring generated after fixation, and/or the spring switch can be fixed by denting and/or bending the spring or on a support of the spring.

In order to obtain a desired electrical conductivity, the non-ferrous metal can be copper, the spring has a defined copper layer so that the spring overall has a low specific resistance of less than 0.14 ohm * mm ² /m, and / or the multi-layer material which the spring is manufactured can have a low specific resistance of less than 0.14 ohm * mm ² /m. For example, certain alloys for spring applications achieve a specific resistance of less than 0.14 ohm * mm ² /m and could therefore be used as a spring material for the spring in order to achieve the desired corresponding electrical conductivity. But the specific resistance of the entire spring can also be influenced by a plating with a low specific resistance in such a way that the desired electrical conductivity is obtained.
The plating of the spring can in particular be applied to a spring core without an intermediate layer.

Furthermore, the spring can be designed for use at higher temperatures, in particular of more than approximately 100 ° C. This can be achieved in particular by selecting appropriate spring materials. For example, the operating temperature of spring steel can be between 80°C and 300°C, depending on the type. Since the spring properties of the spring are essentially determined by the spring material, for example the spring steel, and are only slightly influenced by the plating, the operating temperature of the spring essentially determined by the operating temperature of the spring material. By appropriately selecting, for example, a suitable type of spring steel with an operating temperature of more than approximately 100 ° C, the spring can be designed for use at this temperature.

Finally, the spring can be designed for frequent bending changes. This can be achieved in particular by selecting a suitable spring material, in particular spring steel; For example, a copper-beryllium alloy is suitable for frequent bending changes or high dynamic loads, but higher dynamic load ranges can also be achieved by selecting appropriate types of spring steel and a spring with such types of spring steel made of spring material can be designed for frequent bending changes and the corresponding dynamic load.

In a further embodiment, the invention relates to an overload relay with an overload release, an auxiliary switch which has a snap switch according to the invention and as described herein, and a mechanical transmission device for transmitting a tripping process from the overload release to the snap switch of the auxiliary switch, the transmission device during a tripping process a movement of the current-carrying spring of the jump switch causes the jump switch to switch.

Finally, a further embodiment of the invention relates to a trip indicator for a switching device, which is designed to signal a tripped state of a switching device mechanically coupled to it, and has a snap switch according to the invention and as described herein, wherein when the switching device is triggered via the mechanical Coupling causes a movement of the current-carrying spring of the jump switch in such a way that the jump switch switches.

Further advantages and possible applications of the present invention emerge from the following description in conjunction with those in the drawings illustrated embodiments.

• Fig. 1 ein Ausführungsbeispiel eines Überlastrelais mit einem Sprungschalter gemäß der Erfindung;
• Fig. 2 eine Detailansicht der Auslösemechanik des Überlastrelais von Fig. 1;
• Fig. 3 eine Detailansicht der Sprungfeder des im Überlastrelais von Fig. 1 eingebauten Sprungschalters;
• Fig. 4 ein weiteres Ausführungsbeispiel eines Überlastrelais mit einem Sprungschalter, bei dem die Sprungfeder durch eine Blattfeder implementiert ist, die eine durch eine Beule ausgebildete Justagestelle besitzt, gemäß der Erfindung;
• Fig. 5 ein weiteres Ausführungsbeispiel eines Überlastrelais mit einem Sprungschalter, bei dem die Sprungfeder durch eine Blattfeder implementiert ist, die aus einem teilplattierten Band ausgestanzt ist, gemäß der Erfindung; und
• Fig. 6 eine Draufsicht auf die Sprungfeder des im Überlastrelais von Fig. 5 eingebauten Sprungschalters.

The drawings show in

• Fig. 1 an embodiment of an overload relay with a snap switch according to the invention;
• Fig. 2 a detailed view of the tripping mechanism of the overload relay Fig. 1 ;
• Fig. 3 a detailed view of the spring in the overload relay Fig. 1 built-in jump switch;
• Fig. 4 a further embodiment of an overload relay with a snap switch, in which the spring is implemented by a leaf spring having an adjustment point formed by a dent, according to the invention;
• Fig. 5 a further embodiment of an overload relay with a spring switch, in which the spring is implemented by a leaf spring stamped from a partially plated strip, according to the invention; and
• Fig. 6 a top view of the spring in the overload relay Fig. 5 built-in jump switch.

In the following description, identical, functionally identical and functionally related elements may be provided with the same reference numerals. Absolute values are given below only as examples and are not to be understood as limiting the invention.

Fig. 1 shows an exemplary embodiment of an overload relay 10, which includes an overload release 12 and an auxiliary switch 14. The overload release 12 has a bimetal release per electrical phase, as is the case, for example DE 3840064 A1 is described. Increased current flow in the individual phases, as can occur, for example, in the event of an overload, causes the bimetal releases to deform or different current flows in the individual phases, as they do For example, which can occur when a phase fails, cause corresponding differences in the deformation of the bimetal trigger, whereby a mechanical transmission device, which will be described in detail below, is actuated. This actuation in turn results in a triggering process being transmitted to a snap switch of the auxiliary switch 14.

In the event of a trip, a tripping process is transmitted from the overload release 12 to the snap-action switch via the mechanical transmission device as described below: if the bimetal release of the overload release 12 is deformed, bridges 22 'and 22" are moved and an actuating lever 22 is changed in position (in the example shown shifted and rotated). in turn presses on the spring 16 (for example a so-called cracking frog), so that it jumps from a first rest position to a second rest position. In the first rest position, normally closed contacts 18 of the auxiliary switch 14 are closed and normally open contacts 20 of the auxiliary switch 14 are opened. In the second rest position, the normally closed contacts 18 are open and the normally open contacts 20 are closed. By opening the normally closed contacts 18, for example, the power supply to the control circuit of the associated contactor and thus indirectly the power supply to the phases of the circuit to be protected can be interrupted. This corresponds to the tripped state in the event of an overload or the tripped state in the event of a phase failure of the overload relay 10. Via an adjustment mechanism 30 of the tripping threshold, which is operatively connected to the temperature compensation strip 26, the transmission of the tripping process from the overload release 12 can also be made more precise, in particular to the operating conditions of the overload relay 10 be adjusted.

Fig. 2 shows the structure of the jump switch in the auxiliary switch 14 in detail. Here it is clear that the actuating lever 22, the release lever 24, the Temperature compensation strip 26 and the spring actuation lever 28 comprising mechanical transmission chain for the transmission of a triggering process to the spring 16 can be seen.

The current-carrying spring 16 and its design and storage in the spring switch as well as the production of the spring switch with this spring 16 will now be discussed below with reference to Fig. 3 described: the basic shape of the spring 16 is punched out of a spring steel strip plated on both sides with an electrically conductive non-ferrous metal such as copper. Before installing the spring 16 in the snap switch, the spring 16 is pre-bent. However, pre-bending is not absolutely necessary. For assembly, the spring 16 is fixed under tension at its two ends. The spring can also be fixed at just one or three ends. The spring can also be fixed in a tension-free manner, with tension in the spring only being generated after fixation, for example by dents. In Fig. 3 Two fixations 161 and 162 can be seen at one end of the spring 16 on a support 165 for the spring 16. The other end of the spring 16 can be fixed separately with an aid during assembly, which is removed again after assembly has been completed. In the fixed state in this way, the jump switch is now adjusted, in particular by buckling and/or bending at adjustment points 163, 164 of the spring 16 or on a support of the spring 16, that is, in particular, the jumping of the spring 16 from the first to the second rest position and back is adjusted. For the adjustment, the adjustment points 163, 164 can also be fixed, which can make the deformation easier. What is important here is that the non-ferrous metal plating is partially or even completely displaced at the adjustment points 163 and 164 of the spring 16, i.e. at the points where the spring spring bends and/or buckles. This displacement can have already taken place during plating by partial plating, or after plating by specifically exposing the adjustment points 163 and 164, for example by grinding or denting, or even only during adjustment, for example by partial removal during bending and / or denting. The displacement causes the core of the spring 16, i.e. the actual spring material can receive the desired deformation and the springs 16 have a lower production spread. In order to minimize the disruptive influence of the spring properties of the plated non-ferrous metal on the spring properties of the spring 16, the carrier of the spring 16 can be individually slightly deformed in the partially assembled overload relay or auxiliary switch in order to compensate for any manufacturing tolerances of the spring 16 in an operatively connected functional chain.

Fig. 4 shows the overload relay 10 with the overload release 12 and the auxiliary switch 14, in which the auxiliary switch 14 differs from that in Fig. 1 and 2 In the exemplary embodiment shown, a different configuration of the spring is used: in this case, the spring 16 'has a dent as an adjustment point 166; The adjustment point here is not at the fixings of the spring as in the exemplary embodiments Fig. 1 to 3 intended. The dent is introduced in particular after mounting the spring 16 'and fixing it in the auxiliary switch 14 in order to ensure that the spring 16' in the auxiliary switch 14 is set as precisely as possible.

Fig. 5 shows the overload relay 10 with the overload release 12 and the auxiliary switch 14, with a spring 16" inserted in the auxiliary switch 14, which is punched out of a partially plated strip. The partial plating of the spring is shown in the top view of the spring Fig. 6 shown: approximately in the middle of the spring 16" runs an area 161", which is not plated and extends between two plated areas 162" of the spring 16". Furthermore, similar to the spring 16 of Fig. 3 Adjustment points 163" and 164" are provided.

The invention makes it possible to avoid the use of harmful metals such as copper-beryllium. In addition, the invention enables the production of snap switches with lower manufacturing tolerances for the springs used.

Claims (10)

1. Method for producing a snap-action switch (16, 18, 20), which has a current-carrying snap-action spring (16) which can be brought into two rest positions by mechanical actuation, comprising the following steps:

   - producing the snap-action spring (16) from a multilayer plated material, the plating having at least one layer of a non-ferrous metal and/or a layer of a noble metal,

   - fixing the snap-action spring (16) at at least one end in the snap-action switch, and

   - deforming the fixed snap-action spring (16) at at least one adjustment point (163, 163", 164, 164", 166) during mounting in the snap-action switch (16, 18, 20) in order to adjust the snap-action switch (16, 18, 20),

   - characterized in that a partial or complete displacement of the plating at the adjustment point(s) of the span-action spring (16) either take(s) place in the deforming step or before the deforming step, such that the plating is provided on as large an area as possible and is only displaced at the adjustment point(s).
2. Snap-action switch (16, 18, 20), which has a current-carrying snap-action spring (16) that can be brought into two rest positions by mechanical actuation and is made of a multi-layered plated material, wherein the plating has at least one layer of a non-ferrous metal and/or a layer of a noble metal, which is provided on as large an area as possible and is only partially or completely displaced at the adjustment point(s) of the snap-action spring (16), wherein the snap-action switch (16, 18, 20) is adjusted in that the snap-action spring (16) has been deformed at the at least one adjustment point during mounting in the snap-action switch (16, 18, 20), and wherein the snap-action switch (16, 18, 20) is produced by the method according to claim 1.
3. Snap-action switch according to claim 2,
   characterized in that
   the current-carrying snap-action spring (16) is pre-bent prior to mounting in the snap-action switch (16, 18, 20).
4. Snap-action switch according to either claim 2 or claim 3,
   characterized in that
   the non-ferrous metal is copper and the current-carrying snap-action spring (16) is produced from a copper-plated spring steel strip on both sides by punching out.
5. Snap-action switch according to claims 2, 3 or 4,
   characterized in that
   when the snap-action switch (16, 18, 20) is mounted, the snap-action spring (16) has been fixed at one, two or three ends, either under tension or in a tension-free manner, and a tension of the snap-action spring has been produced after the fixing process, and/or has been adjusted by buckling and/or bending on the snap-action spring (16) or on a carrier of the snap-action spring (16) of the snap-action switch (16, 18, 20).
6. Snap-action switch according to either claim 4 or claim 5,
   characterized in that
   the non-ferrous metal is copper and the snap-action spring (16) has a defined copper layer such that the snap-action spring (16) overall has a low specific resistance of less than 0.14 Ohm * mm²/m, and/or the multilayer material from which the snap-action spring (16) is produced has a low specific resistance of less than 0.14 Ohm * mm²/m.
7. Snap-action switch according to any of claims 2 to 6,
   characterized in that
   the plating of the snap-action spring (16) is applied to a spring core without an intermediate layer.
8. Snap-action switch according to any of claims 2 to 7,
   characterized in that
   the snap-action spring (16) is designed for use at temperatures of more than approximately 100 °C.
9. Overload relay (10) comprising an overload release (12), an auxiliary switch (14), which has a snap-action switch (16, 18, 20) according to any of claims 2 to 8, and a mechanical transmission device (22, 22', 22", 24, 26, 28) for transmitting a release operation from the overload release (12) to the snap-action switch (16, 18, 20) of the auxiliary switch (14), the transmission device causing a movement of the current-carrying snap-action spring (16) of the snap-action switch during a release operation in such a way that the snap-action switch (16, 18, 20) switches.
10. Tripping indicator for a switching device, which is designed to signal a released state of a switching device mechanically coupled thereto and has a snap-action switch (16, 18, 20) according to any of claims 2 to 9, wherein, when the switching device is released, a movement of the current-carrying snap-action spring (16) of the snap-action switch is effected via the mechanical coupling in such a way that the snap-action switch (16, 18, 20) switches.

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