WO2003067621A1

WO2003067621A1 - Electric connecting element, in particular for connecting high currents

Info

Publication number: WO2003067621A1
Application number: PCT/DE2002/004716
Authority: WO
Inventors: Peter Lell
Original assignee: Peter Lell
Priority date: 2002-02-10
Filing date: 2002-12-23
Publication date: 2003-08-14
Also published as: DE10205369B4; DE10296442D2; DE10296442B4; AU2002358450A1; DE10205369A1

Abstract

The invention relates to an electric connecting element (1), in particular for connecting high currents, comprising a housing (3) containing a contact unit (5), the latter having two connection contacts (13, 19) that are fixed to the housing or configured as one piece with said housing, for supplying and discharging an electric current that is to be connected. The two connection contacts are interconnected in an electrically conductive manner inside the housing in the initial state of the connecting element. The connecting element also comprises a material (21) that can be activated, which is provided in the housing, said material generating a gas pressure, which is exerted on the contact unit (5), after activation, whereby the electrically conductive connection is separated by the exertion of said gas pressure. The contact unit (5) comprises a contact element (15) that can be displaced in relation to the fixed connection contacts (13, 19) by means of the exertion of the generated gas pressure. Said contact element is displaced by the exertion of the gas pressure generated in the direction of the axis of the contact unit from its initial position into a final position, in which the electric connection via the contact unit is interrupted.

Description

Electrical switching element, in particular for switching high currents

The invention relates to an electrical switching element, in particular for switching high currents. Switching elements of this type are used, for example, in power station, test and automotive technology for the defined and rapid disconnection of electrical power circuits in an emergency. There is a requirement for such a switching element that its triggering and interruption function must be reliably guaranteed even without maintenance for up to 20 years. Furthermore, such a switching element must not pose any additional hazard potential due to hot gas, particles, throwing pieces or high voltages induced in the switched-off circuit.

A possible area of application in automotive technology is the defined irreversible disconnection of the on-board wiring from the car battery shortly after an accident, in order to avoid ignition sources from sparks and plasma, which arise when, for example, cable insulation has been chafed by the body panel penetrating during the accident or loose cable ends against each other or press against sheet metal parts and rub on. If gasoline leaks at the same time in an accident, such ignition sources can ignite ignitable gasoline-air mixtures that collect, for example, under the hood. Another area of application is the electrical disconnection of an assembly from the vehicle electrical system in the event of a short circuit in the assembly concerned, for example in an electric auxiliary heater.

In the prior art, pyrotechnic fuses are known which are actively controlled for tripping. For example, DE-AS 2 103 565 describes a circuit breaker which comprises a metallic housing which is connected to two mutually spaced connection areas, each with one end of a conductor to be protected. A pyrotechnic element is provided in the housing and is formed by an explosive charge. The explosive charge can be activated by an electrical detonator which comprises an ignition element which is vaporized by a feed current. The housing is filled with an insulating liquid. The axially extended housing has a circumferential groove along which the housing tears open when the explosive charge is detonated. The The housing is broken up into two electrically separate parts, so that the circuit in question is separated. The plasma generated when a circuit with a very high current intensity is disconnected is extinguished by the atomized insulating liquid in this circuit breaker. In a motor vehicle, it can be triggered, for example, by the signal from a shock sensor.

Self-triggering to disconnect the circuit when the conductor to be protected is overloaded is not provided in this known direction because the entire sleeve would have to be heated up to the triggering temperature and then a detonative conversion would not be reliably achieved. Because an explosive can hardly be ignited by simply heating the sleeve, i.e. be brought to detonative implementation. However, this would be e.g. necessary for the housing shape described in DE-AS 2 103 565.

It should be mentioned that pyrotechnics worldwide speak of a detonative implementation if flame front velocities of more than 2000 m / s are defined.

A further disadvantage of this known standard is the problem of approval for devices which have assemblies filled with explosives or even detonators. For this reason, such devices have so far not been used commercially. They are used only very occasionally in research institutes for special experiments. The reasons for this are also the complicated structure, the very low handling safety and the extremely high, very difficult to isolate hazard potential.

Furthermore, in many cases there is a need for a self-triggering function of such a switch or a safety device, for example in order to protect a cable against overload without additional effort for overload sensors. A corresponding switching element should therefore not only have a controllable trigger option, but also the function of a conventional high-current fuse in the form of a Have a fuse that can be handled safely by everyone, as is the case with conventional fuses.

Such high-current fuses have the disadvantage of a switch-off time fluctuating within a wide range after the nominal current strength of the fuse has been reached. A cable secured with it can therefore only be used to a very small extent with regard to its current carrying capacity, e.g. 30% of capacity is used, since otherwise, for example, a cable fire can occur in the event of an overload.

From DE 197 49 133 AI an emergency switch for electrical circuits is known which enables both a self-triggering and a triggerable triggering. For this purpose, an electrical conductor is used, which has a pyrotechnic core. This can e.g. consist of a propellant powder. The pyrotechnic core can be ignited on the one hand by heating the electrical conductor when a permissible current (nominal current) is exceeded. On the other hand, provision is made to ignite the pyrotechnic core by means of a controllable ignition device, for example in the form of a glow wire. DE 197 49 133 AI, however, only represents the principle of such a device, but does not give any indication of possible designs that can be carried out in an advantageous manner. Because the manufacture of a conductor with such a pyrotechnic soul requires considerable effort. In addition, even with such an emergency switch, a safe, quick disconnection of the conductor can only be guaranteed when a detonative explosive is used. With deflagrating, i.e. substances that do not detonate, such as thermite, only burst open the conductor and escape the remaining gas without the conductor being completely separated. Complete separation is then achieved at most by melting the conductor as a result of the current flowing through the fuse.

A fuse is known from US Pat. No. 3,958,206, in which the current to be protected is passed over a switching element filled with an exothermically reactive material, the wall of the fuse element bursting open due to the activation of the exothermically reactive material and interrupting the current. PETN, for example a detonative material, is used as the exothermic reactive material, so that such a fuse is subject to strict approval regulations. The exothermic reactive material can be activated by the heat loss of the current to be protected itself or by an active ignition device. The tearing open of the housing of the switching element would, however, take place in an undefined and unclean manner with a material that burns more slowly, for example with a so-called propellant charge powder. There is a risk that initially only cracks or holes will appear in the switching element and that the remaining wall material only has to be melted by the current to be protected. This affects the response speed of the fuse and is also not permissible for reasons of reliability.

Furthermore, US Pat. No. 3,958,206 discloses a fuse with a switching element in the form of, for example, a flat conductor which is coated with an aluminum layer and a palladium layer arranged thereover. The aluminum and palladium act as exothermic reactive materials, and the exothermic process can be activated by the heat loss of the current to be protected or by means of an activation device.

From the post-published WO 02/35568 AI pyrotechnic switching elements are known which, although largely no longer have the shortcomings described above, are either very inflexible in the design of the switching bridge, complex to manufacture and extremely difficult to control in terms of safety. In any case, this applies to the embodiments in which a deflagrating pyrotechnic material is used to break out a specially designed switching bridge in a partial area over the entire circumference. In the embodiment according to FIG. 9 of WO 02/35568 AI, the gas pressure generated by means of the deflagrating pyrotechnic material additionally exerts an axial tensile force on the switching web, so that it is reliably separated over the entire circumference. However, this embodiment has the disadvantage that one of the connection contacts and thus also the connection cable connected to it performs an axial movement. In many cases this is not acceptable or at least undesirable, even if the axial movement path is relatively short. In particular with high currents to be switched, a switching element must be firmly clamped from both ends or at both connection contacts (even if they are not on one axis). Based on this prior art, the invention has for its object to provide a pyrotechnic switching element in which no movements of parts outside the housing during the switching process and in which - regardless of whether in or outside the housing - no movements of parts associated with Connection cables are connected. In addition, a switching element is to be created which is completely safe from a safety point of view and can be produced in a simple and inexpensive manner.

The invention solves this problem with the features of claim 1.

In the switching element according to the invention, as in the pyrotechnic fuse element according to WO 02/35568 AI, an activatable material can be used for performing the switching process, which only generates a sufficiently high gas pressure without detonation shock waves, as in a detonative implementation would have to be created which are not acceptable for security reasons. As in the embodiment according to FIG. 9 of WO 02/35568 AI, part of the contact unit, via which the current to be switched between two connecting contacts of the contact unit, is axially acted upon by the gas pressure and separated in the axial direction into at least two parts by the gas pressure , The contact unit comprises a contact element which can be acted upon by gas pressure and which can be moved relative to the adjacent connection contact which is fixedly connected to the housing. The contact element is moved during the triggering process from a starting position into an end position in which the two parts of the contact unit are safely separated from one another. Due to the connection contacts connected to the housing or thus formed in one piece, no undesired mechanical movement occurs to the outside.

According to one embodiment of the invention, the contact element is displaceably guided in a connection contact or opposite the connection contact, the displaceable guide being designed in such a way that, at least in the initial state, there is reliable electrical contact via the contact unit. The contact unit preferably comprises a connecting element which is connected at one end to a connection contact and at the other end to the contact element. The connecting element can be formed integrally with the contact element and / or the connection contact or can be connected non-positively or positively to the contact element and / or the connection contact.

To perform the switching process, i.e. disconnecting the electrical connection via the contact unit, the connecting element can be completely separated at least in a partial area or destroyed altogether. Due to the axial movement of the contact element, such a tensile force can be exerted on the connecting element that it tears off, regardless of whether the connecting element has already been weakened, torn, torn or the like in a partial area by activating the activatable material.

In one embodiment of the invention, at its end pointing in the direction of movement, the contact element comprises a compression region which can be plastically deformed by the kinetic energy of the contact element as a result of hitting or resting on the adjacent connection contact or as a result of an integral design with the connection contact.

This ensures, on the one hand, a secure axial separation of the parts of the contact unit and, on the other hand, at least a large part of the kinetic energy is destroyed by the deformation of the compression region and does not have to be completely absorbed by the housing or destroyed by friction between mechanical contact surfaces during the movement of the contact element. With a one-piece design of the contact element and the compression area with the relevant contact, it is also ensured that there are no movable contact surfaces in which an undesirably high contact resistance can arise, for example due to play between the contact surfaces or due to corrosion.

According to the preferred embodiment of the invention, the activatable material is within the contact unit, preferably within the system Connection element contact element, provided. This results in the advantage that the gas pressure not only acts on the contact element, but also that the connecting element is damaged or possibly even completely destroyed by the connecting contact-connecting element-contact element within the connecting element or the system. In any case, this applies when the connecting element or the system connection contact-connecting element-contact element is completely closed or only has openings so small that partial or complete destruction occurs due to the gas pressure. Usually, however, the gas generated will exit through openings in the surrounding space and additionally apply pressure to the contact element or larger areas of the contact element, so that the contact unit is separated by the combined partial destruction of the connecting element and the tensile force additionally generated by pressurizing the contact element he follows.

For this purpose, after activating the activatable material, the gas can enter through at least one opening in the contact unit, preferably in the connecting element, into a space within the housing which is delimited by the contact element, the contact element preferably being sealed off from the housing.

In principle, however, the activatable material can of course also be provided outside or inside and outside of the connecting element or the system of the connecting contact-connecting element-contact element in the housing.

The connection contacts, the connecting element and the contact element can be manufactured as individual parts, all of which have a simple geometric structure and can be easily connected to one another. This results in a small-sized switching element that can also be adapted to customer needs by the simple replacement of the switching tube with the same contact pieces, and at the same time is inexpensive to produce.

The manufacture of the connecting element as a separate part, which is connected to the contact element and the connection contact to form a unit, results in a clean definition of the contact tube-contact piece transition (the transition radius and the wall thicknesses in the area of the switching bridge or the weak point can be found here defined much easier and will be complied with later in the series) Various design options that allow flexible adaptation of the switching element to the respective application without significantly changing the mounting of the switching element. This means a high degree of flexibility in the properties of the switching element with regard to tripping and the effect after tripping, without having to change the assembly lines. Because only a different connecting element has to be used for the adaptation.

The connection between the connection element and the connection contact and / or the contact element can also be carried out in such a way that the connection element is not destroyed by the switching process, but rather only one of the connections to the connection contact or to the contact element is released in that the contact element is axially open the neighboring contact is moved.

Through the use of an activatable material introduced in the switching element, in particular an only deflagrating pyrotechnic substance, which, unlike an explosive charge, only produces a gas or gas / particle mixture, official approval becomes relatively unproblematic - and in the event that this activatable material only Liquids or solids that undergo a volume change when activated, are not even necessary at all. For the configurations of the switching element shown below, which can of course also be designed as a fuse, are in principle suitable for all pyrotechnic or generally gas-generating substances, regardless of how quickly this gas is generated. Detective and deflagrating substances, thermites, pyrotechnic mixtures, liquid gases but also fluids can be used, which expand or gasify their volume purely physically at a certain transition temperature and can therefore be used as a propellant for the separation of the contact unit.

In one embodiment of the invention, a damping material is arranged in the housing in such a way that the movement of the switching element into the end position after the activation of the activatable material is damped. As a result, the housing or the housing parts will be subjected to a much lower mechanical load. In another embodiment, the contact element has a conical outer contour in order to reduce its speed achieved by the action of the gas pressure over a longer braking distance. At the same time, the housing of the switching element can be sealed by this measure.

In a further embodiment, the movement of the contact element is used to displace a material provided between this contact piece and the housing and to press it into the region of the connecting element. This material can then either fix or stabilize the switching state reached after tripping or delete the plasma arc that may arise between the parts still carrying electrical potential.

In one embodiment of the invention, the contact unit, preferably the connecting element, can be designed such that when a threshold current value is exceeded, the contact unit or the connecting element, preferably at one or more defined points, is heated such that the activatable material is activated. For example, the connecting element can consist entirely or partially of an electrically non-conductive material, in particular of graphite or carbon. This results in a rapid heating of the connecting element even with low electrical currents and thus a safe and simple self-triggering of the switching element. In addition, there are relatively low internal pressures necessary for the destruction of the connecting element if the material is brittle or has only a low breaking stress.

The connecting element can also be designed as a simple tube, which consists entirely or partially of an electrically non-conductive or semiconducting material. Here, an electrically highly conductive layer must be applied inside or outside in order to achieve the required small internal resistance of the switching element towards the outside. But here, too, the layer can advantageously be designed such that a region of this layer heats up via the switching element when a certain electric current is exceeded, thereby triggering the activatable material introduced here. This layer can be applied homogeneously or over the entire inner or outer surfaces of the tube also be structured in a spiral, for example, in order to implement desired electrical resistances or heating points. If a semiconductor-like material is used to produce the connecting element, logical switching functions can also be integrated on or in the connecting element, which make it possible to control the triggering of the material which can be activated without any further major outlay or use of parts. This makes it possible to implement a large number of variants for external triggering, for example by supplying an ignition current, supplying information and energy via static or changeable magnetic, electrical or electromagnetic fields, etc.

The connecting element can also be designed as a simple tube with an internal wire spiral for the self-triggering of the switching element when the wire spiral is heated up to the triggering temperature of the activatable material introduced here. The wire spiral can be electrically connected at both ends to the connection contact or the contact element.

In another embodiment, the connecting element can also be designed as a simple tube with an external wire spiral for self-triggering of the switching element when the wire spiral heats up to the triggering temperature of the activatable material introduced outside the contact tube.

Of course, the connecting element in all of the aforementioned variants can be designed as a simple tube with one or more openings (for example bores made radially from the inside to the outside), so that either the activatable material introduced into the inside of the tube flows outward into the housing and thus onto the outside of the contact tube to allow surfaces of the contact element to act, or to have the activatable material introduced outside the contact tube triggered by the activatable material introduced in the contact tube, in particular for triggering the propellant charge powder introduced outside the contact tube by means of an electrical igniter provided in the connecting element, with or without an additional charge. The connecting element can have a preferably circumferential weakening or, overall, act as a weakening in the connection contact-connecting element-contact element system, which serves to cause the contact unit to be disconnected in a defined manner along the weakening in order to achieve a current interruption. On the other hand, the weakening in the (current-carrying) cross section of the connecting element can be designed in such a way that the current flowing through the switching element in the region of the weakening, which has an increased resistance, generates such a large power loss that, if a predetermined current is exceeded, the self-triggering of the here introduced activatable material is specifically reached at this point without having to heat the switching element as a whole. The heating will thus also take place quickly, as desired.

Further embodiments of the invention result from the subclaims.

The invention is explained in more detail below with reference to exemplary embodiments shown in the drawing. The drawing shows:

Figure 1 is a schematic representation of an embodiment of a switching element with an integrated connecting element and a contact element displaceable in the terminal contact.

2 shows a schematic representation of the system of connection contact-connecting element-contact element, in which the connecting element is designed as a separate tubular part;

3 shows a schematic representation of an embodiment of a switching element with a separate connecting element and a contact element which can be displaced in the connection contact and which is sealed against the interior of the housing by self-lidging;

FIG. 4 shows a schematic illustration of an embodiment similar to FIG. 3, in which the movement of the contact element causes a movement in the starting position. material in front of the contact element is displaced into the space behind the contact element;

FIG. 5 shows a schematic illustration of an embodiment similar to FIG. 3, in which a device for resetting the contact element from the end position into the starting position is provided;

6 shows a schematic representation of an embodiment of a switching element with a separate connecting element and a contact element which is connected to the relevant contact via a compression region;

7 to 9 a schematic representation of different embodiments for a connecting element with which a self-triggering of the switching element can be realized;

10 shows a schematic illustration of an embodiment of a switching element with a separate connecting element and a contact element which is guided displaceably in a pot-shaped connection contact; and

Fig. 11 is a schematic representation of an embodiment of a switching element similar to Fig. 10, wherein the cup-shaped connection contact also serves as a housing part and a resetting device is provided for resetting the contact element from the end position to the starting position

Fig. 1 shows a schematic representation of a first embodiment of a switching element 1, which comprises a housing 3, in which a contact unit 5 is arranged. In this embodiment, the housing has two housing halves 7, 9, which consist of a non-conductive material, so that it is ensured that the current flows exclusively via the contact unit 5. The housing halves 7, 9 are held by means of an outer housing part 11 encompassing them and fixing them to form an entire housing. The contact unit 5 comprises a first connection contact 13, a contact element 15 and a connection element 17 provided therebetween, which is integrated with the connection contact and the contact element, and a second connection contact 19 which has a recess 19a in which a preferably cylindrical extension 15a of the contact element 15 so It is held that a secure electrical contact between the contact element 15 and the connection contact 19 is ensured and that with an appropriate force a displacement of the extension 15a in the recess 19a is possible when the switching element 1 triggers.

The electrical current supplied from the outside to the switching element 1, for example the right-hand connection contact 19 via an electrical conductor (not shown), for example a cable, then flows via the connection contact 19, the contact element 15 and the connecting element 17 to the left-hand connection contact 13, which likewise has an electrical connection Conductor (not shown) of the circuit to be switched is connected.

An activatable material is provided in the system consisting of the connection contact 13, the connecting element 17 and the contact element 15. This can be a mixture of a thermally sensitive and a thermally very stable propellant powder.

However, the activatable material can also be a liquefied petroleum gas (if a transition or release temperature is exceeded, the liquefied gas boils, evaporates and gas is produced which triggers the switching process) or a thermite which generates gas after its activation. The activatable material can also be a gel-like or pasty mass (this would change the volume or gasify again at a triggering temperature), a fluid with a certain low vapor pressure (this would then boil or gasify again at a triggering temperature), a memo material (its volume would change if it was warmed up to its release temperature and then returned to the shape it had when it was warm) or a pyrotechnic substance, in particular a suitable propellant powder, which when heated would ignite gas temperature or simply ignited by a conventional igniter or pill.

The activatable material 21 can be activated by means of an igniter 23, which is provided in the connection contact 13. The igniter 23 is secured by means of a sealing element 25 and a screw plug 27 against being pushed out. If the igniter is ignited by electrical actuation, the activatable material is hereby activated and gas is generated explosively, as a result of which the connecting element 17 breaks out and the circuit is interrupted. Even if the connecting element 17 would not be completely separated or destroyed by the gas pressure alone, the gas enters the space 29 surrounding the connecting element within the housing 3, so that the rear surfaces 15b of the contact element are acted upon by the gas pressure. This creates an additional tensile stress in the connecting element 17 (in addition to the tension generated by the pressure on the end wall within the recess in the contact element 15), which leads to a complete tearing of the connecting element 17 while moving the contact element in the direction of the right-hand terminal contact 19.

In the embodiment in FIG. 1, this movement of the contact element is limited in that the right housing half 7 has a conical stop surface 31 which interacts with a conical stop surface 33 of the contact element 15. The path of movement is determined by the axial distance between the two stop surfaces in the starting position of the contact element 15. The angles of the conical stop surfaces 31, 33 are preferably selected such that self-locking occurs when the contact element 15 moves into the connection contact 19, and the contact element 5 is thus securely fixed in the end position. At the same time, the conical stop surfaces 31, 33 serve to achieve a radial bracing between the contact piece and the housing part 7 and a bracing of the housing parts 7, 9 within the outer housing part 11 in order to achieve a sealing effect between the relevant parts, so that none significant gas flow can escape to the outside of the switching element. The problematic parting plane in the axially divided housing halves previously used in the conventional pyrosafety devices (here the hot gas flows out in the event of tripping and thus injures the hand that is just enclosing the switching element or the vicinity of the switching element) is radially encircled by the outer housing part 11, so that the In the region of the parting plane, hot gas present on the inside of the housing part initially strikes the outer housing part 11 and is cooled there. The areas of the two housing halves 7, 9 which are in contact with the housing part 11 and which, for example, consist of plastic, act self-lidging, ie sealing, as a result of the gas pressure.

The embodiment of a switching element shown in Fig. 1 can of course also have a self-timer function in order to automatically, e.g. to be able to disconnect the circuit when the igniter 23 fails to ignite: If current flows through the contact unit 5 in the amount of the previously determinable n times the nominal current of the switching element, the connecting element heats up as a result of the power loss at its electrical resistance such that the triggering temperature of the activatable material 21 is reached and this is activated. After activation, the activatable material generates a gas pressure, by means of which the connecting element 17 is separated in the manner described above. No activation device (ignition device) and therefore no external ignition signal is required for this auto-ignition function or autoignition function.

A propellant charge powder consisting of one or more components can be selected as the activatable material. For example, a component with a low trigger temperature or low activation energy can be used in order to ignite a further (main) component, the combustion gases of which then ultimately destroy the housing. This makes it possible to ignite the mixture even at very low temperatures and thus to optimally load a cable to be protected with the switching element. A substance can therefore be selected for the main component that ignites only at very high temperatures. This is particularly advantageous since such substances generally have a very high resistance to aging. The ignitability of the mixture can therefore be increased even with long-term and / or relatively high heating of the connection tion element 17 are guaranteed, the thermally sensitive material only needs to be able to ignite the main component.

Fig. 2 shows a schematic representation of the system connection contact-connecting element-contact element similar to the relevant system in Fig. 1, but the connecting element 17 is formed as a separate tubular part. The thin-walled pipe section is thus no longer an integral part of the system, but rather is inserted as an extra component between or in the connection contact 13 and the contact element 15. This ensures that this connecting element 17 can be produced very evenly from switching element to switching element. In addition, the critical transition radius now also becomes the chamfer of the bore of the connection contact 13 or the contact element 15, which is much easier to control in production. The connecting element can be inserted into corresponding bores in the connection contact 13 or in the contact element by means of a sealing element, for example an O-ring 15 be used to prevent water or water vapor from penetrating into the bore or to prevent any gas slippage after triggering in order to allow the pressure increase in the connecting element 17 to become sufficiently rapid, high and even.

FIG. 3 shows a further embodiment of a switching element 1, which in principle arises from the combination of FIGS. 1 and 2. Furthermore, the peripheral walls of the connection contact 13 and the contact element 15 are already sealed in the starting position (shown in FIG. 3) against the inner wall of the housing 3 or the inner walls of the housing halves 7, 9. This takes place by means of a self-eyelid design of the outer regions of the connection contact 13 and of the contact element 15, that is to say a groove is provided in the relevant front wall in such a way that a circumferential thin wall 35 is created which is pressed against the inner wall of the housing 3 by the gas pressure , This prevents the ingress of water or water vapor from the outside and, at the same time, prevents gas from escaping after the switching element has been triggered: The thick-walled plastic housing parts shown here no longer cause self-loosening; gas could therefore escape to the outside without the sealing system shown here flow of the switching element. Instead of the self-suffering design of the connection contact and the contact element, of course, any other suitable sealing system can also be used. For example, O-rings can be inserted between the adjacent walls of the housing 3 and the connection contact 13 or the contact element 15.

FIG. 4 shows a representation in longitudinal section similar to the embodiment according to FIG. 3, but here the right connection contact 19 is formed integrated with the housing. At the same time, an outer housing part is dispensed with. This function is also taken over by the connection contact or the cup-shaped housing part formed thereby. The system consisting of the left connection contact 13, the connecting element 17 and the contact element 15 together with the electrically insulating second housing part 9 is inserted, for example screwed, into this housing part. This further simplifies the switching element.

Arranged in the direction of movement in front of the contact element 15 is a liquid, gel-like, pasty or powdery medium 39 which, after the switching process has been triggered, is driven by the movement of the contact element 15 into the connection contact 19 into the space surrounding the broken-up connecting element 17 and a plasma arc which is produced there can delete or just defined the movement of the contact element 15 brakes or dampens. For this purpose, one or more channels 37 are formed in the contact element, which connect the space in the direction of movement in front of the end face of the contact element 15 to the space surrounding the connecting element 17. The viscosity of the medium is selected so that the medium is only pressed through the channels 37 when pressure is applied as a result of the movement of the contact element 15, whereas in the initial state it remains in the relevant room. Of course, the channels could also be closed with a membrane (not shown) which only bursts when a (possibly relatively low) pressure of the medium 39 is exceeded and is pressed through the channels 37.

The switching element constructed in this way is also closed to the outside; Nothing is expelled or blown out, so that the assembly, even when using Explosives is exempt from the most important provisions of German and foreign explosives laws.

As shown in FIG. 4, the connection contact 19 and the contact element 15 or the extension 15a can be provided for fixing the contact element in its end position. For example, as shown in FIG. 1, a circumferential groove 55 or one or more individual recesses or depressions can be provided in the bore or recess 19a of the connection contact 19, preferably in the end region thereof. The material of the extension 15a of the contact element 15 is then to be selected such that the material begins to flow as a result of the force with which the extension 15a is pressed into the recess 19a (in particular against its end or bottom) and enters the groove 55 , The two parts are thus practically fixed by creating a positive connection.

Of course, the means for fixing the contact element 15 in the end position can also be designed, for example, as a latching means in or on the connection contact 19 and on the contact element 15, for example as an elevation in the inner wall of the recess 15a and as a groove or recess on the contact element 15 or on the extension 15a ,

The embodiment shown in Fig. 5 is essentially identical to the embodiment according to Fig. 4, but additionally has a reset device 41, by means of which the contact element after the switching process, i.e. moving to the final state can be moved back to the initial state. The reset device 41 can, as shown in FIG. 5, be designed, for example, as a simple reset screw which is arranged axially in the connection contact 19 and acts on the end face of the extension 15a of the contact element 15 for the reset. This makes it possible to close the circuit again after switching off and, for example, to maintain emergency operation for a certain time.

In this case, the connecting element 17 is provided with one or more openings in the wall, via which the openings after the activatable material has been activated 21 generated gas enters the space surrounding the connecting element and also acts on the rear end face of the contact element 15. The openings or their position and overall cross section are selected such that the connecting element is not destroyed, but is pulled out of the contact element 15 or the connecting contact 13 at one end. This ensures that an electrical contact via the contact unit 5 is restored by resetting the contact element 15 to the initial state.

In the switching element according to FIG. 5, channels in the contact element 15 have also been dispensed with, since an O-ring is used as the sealant instead of the contact element being self-lidded. Due to the high pressure generated by the contact element during the switching movement, the medium can pass through the gap between the outer wall of the contact element 15 and the inner wall of the housing via the O-ring into the space surrounding the connecting element.

Fig. 6 shows a further embodiment of a switching element 1, in which the housing 3 consists of a cup-shaped part 9, which consists of an insulating material or is designed to be insulating against the connection contact 13 and which has an axial opening for receiving the connection contact 13, as well as from a housing part 7 made of an electrically conductive material, which simultaneously forms the connection contact 19. The system consisting of connection contact 13, connection element 17 and contact element 15 additionally has a compression area 45 in the direction of movement in front of the contact element 15, which can be designed as a cylindrical wall which is connected at the other end to a stop element 47 which is supported on the connection contact 19 , Of course, the compression area 45 and the stop element 47 also consist of an electrically conductive material. The compression area is designed such that a plastic deformation occurs as a result of the pressure exerted on the contact element during the switching process, so that the contact element 15 travels a predetermined movement path in order to ensure that the contact unit 5 is reliably separated. Of course, the contact element 15, the compression area 45, the stop element 47 and the connection contact 19 can also be formed in one piece. FIG. 7 shows a schematic illustration of an embodiment of a separately formed connecting element 17, which can be combined with each of the embodiments described above. The connecting element 17 consists of a carrier tube 17a, an externally applied, electrically highly conductive layer 17b (this absorbs the electrical current of the electrical current to be protected or later switched via the switching element), an inner structuring 17c (around the contact surface for the inner one) to increase activatable material and at the same time to simplify, accelerate or make the bursting of the carrier tube 17a by the internal pressure generated by the activatable material after the triggering of the switching element or more reliable over the entire circumference) and from a sealing system 49 which, on the one hand, prevents the ingress of water or prevent water vapor in the connecting element 17 and at the same time ensure gas tightness after the activation or activation of the introduced activatable material. Depending on the application or switching and triggering task, the individual properties or features listed here can also be omitted. In the simplest case, only a simple metal tube with or without any weakening in its wall thickness is used for the connecting element and is thus simply placed between the connection contact 13 and the contact element 15 of the switching element 1.

8 is a schematic illustration of another embodiment of the connecting element 17, consisting of a carrier tube 17a, an electrically highly conductive layer 17b which is only applied externally to both ends of the carrier tube 17a (here it only takes on the task of contacting the terminal contact 13 or to the contact element 15), an internally inserted helical turn 51 made of a material with a specific resistivity, which heats up so far when current flows through that the activatable material provided in the connecting element is activated. In this way, a self-triggering of the switching element can be achieved. As in FIG. 7, a sealing system 49 is again provided. Depending on whether or not a bypass to the inserted spiral for the electrical current via the switching element is desired, the electrically conductive layer applied on the outside of the switching tube is closed over the entire surface of the tube and more or less thick or with more or less highly electrically conductive layer material. FIG. 9 shows a schematic illustration of a further embodiment of the connecting element 17, which is largely identical to the embodiment in FIG. 8. However, the helical turn 51 is arranged on the outside on the circumference of the carrier tube 17a in order to trigger an activatable material provided outside the switching tube. In this embodiment of the connecting element 17, one or more bores or openings 43 are provided in the wall of the support tube 17a, so that the gas generated by the activatable material provided on the inside can flow out to an activatable material introduced on the outside and can also activate it, or simply, in order to give the activatable material, after it has been triggered, the possibility of also pressing the surface of the contact pieces outside, in order to increase the push-out force of the contact element 15.

10 shows a switching element 1, in which the connection contacts 13, 19 simultaneously take over the function of housing halves 7, 9 or are formed in one piece with them. The connection contacts or housing parts are electrically insulated from one another via a ring 53 made of insulating material. As in FIG. 1, an outer housing part 11 is provided, which comprises the connecting contacts 13, 19 and the ring 53 and fixes them to form a unit. The contact element 15 is guided axially displaceably in the space between the pot-shaped connection contacts 13, 19 and the ring 53 and is connected to the connection contact 13 via a connection element 17 designed as a wire or the like. In the starting position, the contact element 15 is positioned such that it is electrically conductively connected to the connection contact 19 via its peripheral wall. The activatable material 21 is arranged in a chamber in the connection contact 13 and can be activated by means of the igniter 23 provided in the connection contact 13 as in the embodiments according to FIGS. 1 to 6. The generated gas reaches the space between the connection contact 13 and the rear of the contact element 15 via channels or openings 55.

In the embodiment according to FIG. 11, the connection contact 19, similar to the embodiment in FIG. 5, is of cup-shaped design such that an outer housing part 11 can be dispensed with. In the initial state, a disc-shaped con Clock element 15 electrically connected to the connection contact 13 via a connecting element 17 designed as a wire or the like. The peripheral walls of the contact element 15 make electrical contact with the connection contact 19. As in FIG. 10, the connecting element 17 tears during a switching operation due to the pressurization of the connecting element 15 and the tensile force generated thereby on the connecting element 17.

Furthermore, as in the embodiment in FIG. 5, a reset device 41 is provided, by means of which the disk-shaped contact element 15 can be moved from its end position back to the starting position after a switching operation.

In conclusion, it should be pointed out that all of the features described in connection with each of the individual embodiments described above can also be combined with other embodiments, where appropriate.

Claims

claims

1. Electrical switching element, in particular for switching high currents,

a) with a housing which comprises a contact unit,

b) wherein the contact unit has two fixedly connected to the housing or thus integrally formed connection contacts for supplying and discharging an electrical current to be switched and

c) the two connection contacts being electrically conductively connected within the housing in the initial state of the switching element,

d) with an activatable material provided in the housing which, after activation, generates a gas pressure to act on the contact unit, the electrically conductive connection being separated by the action of the gas pressure,

e) the contact unit comprising a contact element which can be moved relative to the fixed connection contacts when the generated gas pressure is applied,

f) which is moved by the application of the generated gas pressure in the direction of the axis of the contact unit from its starting position to an end position in which the electrical connection via the contact unit is interrupted.

2. Switching element according to claim 1, characterized in that the contact element is guided displaceably in a connection contact or with respect to the connection contact.

3. Switching element according to claim 1 or 2, characterized in that the contact unit comprises a connecting element which is connected at one end to a connection contact and at the other end to the contact element.

4. Switching element according to claim 3, characterized in that the connecting element is integrally formed with the contact element and / or the connection contact.

5. Switching element according to claim 3 or 4, characterized in that the connecting element is non-positively or positively connected to the contact element and / or the connection contact.

6. Switching element according to one of the preceding claims, characterized in that the contact element at its end pointing in the direction of movement comprises a compression region which is plastically deformed by the kinetic energy of the contact element as a result of impact or contact with the adjacent terminal contact or as a result of an integral design with the terminal contact. is cash.

7. Switching element according to one of the preceding claims, characterized in that the activatable material is provided within the contact unit, preferably within the system connection contact-connecting element-contact element.

8. Switching element according to claim 7, characterized in that after the activation of the activatable material, the gas enters through at least one opening in the contact unit, preferably in the connecting element, into a space within the housing which is delimited by the contact element, the contact element preferably is sealed against the housing.

9. Switching element according to one of claims 3 to 8, characterized in that due to the pressurization the connecting element tears open at least at one point or tears off completely or the contact element from the connecting element o- which the connecting element is separated from the connection contact and that the contact element is axially displaced relative to the fixed connection contacts, whereby the electrical connection within the contact unit is interrupted.

10. Switching element according to one of the preceding claims, characterized in that the activatable material is a deflagrating pyrotechnic material.

11. Switching element according to one of the preceding claims, characterized in that a damping material is arranged in the housing in such a way that the movement of the switching element into the end position after the activation of the activatable material is damped.

12. Switching element according to one of the preceding claims, characterized in that a material to be displaced by the movement of the switching element, preferably a liquid or a medium of a certain viscosity, is provided in the housing, this material being displaced into space by the movement of the contact element which arises after the separation of the contact unit between the parts of the contact unit and surrounds it.

13. Switching element according to one of the preceding claims, characterized in that a preferably electrically controllable ignition device is provided for activating the activatable material.

14. Switching element according to one of the preceding claims, characterized in that the contact unit, preferably the connecting element, is designed such that when a threshold current value is exceeded, the contact unit or the connecting element, preferably at one or more defined points, is heated such that the activatable material is activated becomes.

15. Switching element according to one of the preceding claims, characterized in that the contact unit has a reset device, by means of which the contact element moved into the end position into a position, preferably the output position, is movable, in which there is an electrical contact between the two connection contacts.

16. Switching element according to one of the preceding claims, characterized in that the connection contact 19 and the contact element 15 have means for fixing the contact element in its end position, which is formed, for example, as a circumferential groove or as one or more individual recesses or depressions in the recess of the connection contact are, preferably in its end region, the material of the extension of the contact element 15 engaging in the recess being selected such that the material begins to flow due to the force with which the extension is pressed into the recess and into the groove or the one or several individual recesses or depressions.