DIRECT CURRENT ELECTRIC CIRCUIT INTERRUPTING SWITCH ASSEMBLY

Abstract

A direct current electric circuit interrupting switch assembly is disclosed that comprises a pyroswitch assembly, which comprises at least two pyroswitches, which are connected in parallel with each other and are each per se integrated in its respective electrically conductive branch together forming a second branch of the primary electric conductor the switch assembly, with a first, preceding pyroswitch and a second, subsequent, or last pyroswitch. Each of said pyroswitches comprises an interrupting member, by means of which each circuit with each of the pyroswitches is either connected during normal operation or is interrupted by displacing each corresponding interrupting member into another position, when a pre-determined condition is met.

Claims

1. A direct current electric circuit interrupting switch assembly comprising: a primary electric conductor and a secondary electric conductor adapted for integration between an electric source and at least one load; wherein by means of said conductors of the switch assembly a primary terminal of said electric source is electrically connectable with a primary terminal of each electric load, and a secondary terminal of said electric source is electrically connectable with a secondary terminal of each electric load; wherein the primary electric conductor of the switch assembly comprises two branches, which are in parallel connected with each other, the first branch including an electric fuse with a melting member, and the second branch including a pyroswitch assembly with at least one interrupting member, which is capable of interrupting current flow in said second branch of the primary electric conductor extending through said pyroswitch assembly, as well as an actuator, which is capable of activating said pyroswitch assembly due to the interruption of said second branch of the primary electric conductor by means of explosion of at least one chemical reactant contained therein by means of an electric impulse; wherein said pyroswitch assembly comprises at least two pyroswitches which are connected in parallel with each other, with the at least two pyroswitches comprising a first pyroswitch and a last pyroswitch, wherein each of the at least two pyroswitches comprises an interrupting member, by means of which each circuit path including a pyroswitch is either connected during normal operation or is interrupted by movement of the corresponding interrupting member into another position; and wherein said actuator, via the least two interrupting members in the at least two pyroswitches is electrically connectable with the secondary electric conductor; said actuator further comprising: an actuator electric circuit which is electrically connected with said primary electric conductor such that it is connected with said electric voltage source and said electric load in series with said first and second branches of the primary conductor; wherein said actuator electric circuit comprises at least one irreversible thermal electric fuse with a contact member, which is during normal operation of the switch assembly interrupted, and which is closed when an electric overload occurs; wherein said actuator electric circuit comprises at least one electromagnetic reed switch, which is during normal operation of the switch assembly interrupted, and which is closed when a pre-determined value of the electric current within the switch assembly is exceeded; and wherein said thermal electric fuse and said electromagnetic reed are connected in parallel with each other; wherein each pyroswitch comprises an electric initiating member capable of initiating an explosive chemical reaction of at least one chemical reactant contained therein by means of an electric impulse; wherein each pyroswitch further comprises an actuating member, which is capable of moving the interrupting member from a first position in contact with the primary conductor into another position where the circuit in the primary conductor is interrupted; wherein the electric initiating member of the first pyroswitch is electrically connected with the actuator electric circuit and the actuating member of the first pyroswitch is capable of moving the interrupting member of the first pyroswitch from its uninterrupted position to another position, whereby the circuit through the said pyroswitch is interrupted and the interrupting member is after movement in electrically conductive contact with an electric initiating member of a subsequent pyroswitch member, whereby the interrupting member in the last pyroswitch is after movement in electrically conductive contact with the secondary conductor.

2. The switch assembly according to claim 1, further comprising at least one additional conductor connected to said actuator electric circuit wherein said circuit is then connected with at least one external sensor, so that said actuator may be, via said additional conductor, provided with a signal, which is required for initiating the electric initiating member of each pyroswitch and which is received from said external sensor, which is adapted for monitoring electric current within an external circuit or at least one further physical characteristic external to the switch assembly.

3. The switch assembly according to claim 1, wherein at least one of the interrupting members is capable of being mechanically actuated from an initial position to a second position within the second branch of the primary electric conductor.

4. The switch assembly according to claim 1, wherein the interrupting member of the last pyroswitch of the pyroswitch assembly in its second, that is, interrupted position, is brought into an electrically conductive contact with the secondary conductor.

5. The switch assembly according to claim 1, wherein each electrical initiating member for each pyroswitch is electrically connected to said actuator electric circuit and is capable of electrically connecting to the initiating member of the subsequent pyroswitch in the pyroswitch assembly, wherein the initiating member of the last pyroswitch in the pyroswitch assembly is capable of electrically connecting with the secondary conductor in the switch assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present disclosure will now be explained in some more detail by means of an embodiment, which is schematically presented in attached figures, wherein

[0029] FIG. 1 presents a switch assembly together with a corresponding electric circuit during normal operation of the electric circuit;

[0030] FIG. 2 presents the switch assembly according to FIG. 1 in the first step of interrupting the electric circuit at the presence of an external disturbance or electric overload in the electric circuit;

[0031] FIG. 3. presents the switch assembly according to FIG. 1 during the subsequent step of interrupting the electric circuit at the presence of an external disturbance or electric overload in the electric circuit; and

[0032] FIG. 4. Presents the switch assembly according to FIG. 1. after the electric circuit has been completely interrupted due to an external disturbance or electric overload in the electric circuit.

DETAILED DESCRIPTION

[0033] A direct current interrupting switch assembly 1 is therefore schematically shown in FIGS. 1-4. and is by establishing an electric connection via a primary electric conductor 11 and a secondary electric conductor 12 suitable for integration between a direct voltage electric source 2 and at least one electric load 3, so that by means of said conductors 11, 12 of the switch assembly 1 the primary terminal 21 of said electric source 2 is electrically connectable with a primary terminal 31 of each electric load 3, and a secondary terminal 22 of said electric source 2 is electrically connectable with a secondary terminal 32 of each electric load 3, wherein the primary electric conductor 11 of said switch assembly 1 comprises two branches 111, 112, which are in parallel connected with each other, of which the first branch 111 includes an electric fuse 4 with a melting member 41, and the second branch 112 includes a pyroswitch 5, which is capable of interrupting said branch 112 of the primary electric conductor 11 extending through said pyroswitch 5, as well as an actuator 52, which is capable of activating said pyroswitch assembly 5 due to the interruption of said second branch 112 of the primary electric conductor 11 by means of explosion of at least one chemical reactant contained therein by means of an electric impulse.

[0034] As further evident in FIGS. 1-4, said pyroswitch assembly 5 may comprise at least two pyroswitches 5′, 5″, which are connected in parallel with each other and are each per se integrated in its respective electrically conductive branch 112′, 112″ together forming said second branch 112 of the primary electric conductor 11, namely a first i.e. substantially preceding pyroswitch 5′ and a second i.e. substantially subsequent pyroswitch 5″. Each of said pyroswitches 5′, 5″ comprises an interrupting member 51′, 51″, by means of which each branch 112′, 112″ of each of the pyroswitches 5′, 5″ is either connected during normal operation or is interrupted by displacing each corresponding interrupting member 51′, 51″ into another position, when each pre-determined condition is met. In the shown example according to FIGS. 1-4 the pyroswitch assembly 5 comprises two pyroswitches, however in general it is possible to use a pyroswitch array comprised of three or more pyroswitches 5′, 5″, 5′″ and so on in pyroswitch assembly 5.

[0035] Said actuator 52 is via a sequence of at least two interrupting members 51′, 51″ of pyroswitches 5′, 5″ of the pyroswitch assembly 5 electrically connectable with the secondary conductor 12 of the switch assembly 1 and comprises an electric circuit 523, which is in addition to said parallel branches 111, 112 integrated in said primary electric conductor 11 in such a manner, that it is connected with said electric voltage source 2 and said electric load 3 in serial with said branches 111, 112 of the primary conductor 11. Said electric circuit 523 consists of at least one irreversible thermal electric fuse 524 with a contact member 524′, which is during the regular operation of the switch assembly 1 interrupted and is closed i.e. set into uninterrupted state only when an electric overload occurs, as well as of at least one electromagnetic reed switch 525 with an interrupting member 525′, which is during regular operation of the switch assembly 1 interrupted and is closed i.e. set into uninterrupted state only when a pre-determined value of the electric current within the switch assembly 1 is exceeded. Said fuse 524 of the actuator 52 and said electromagnetic switch 525 of the actuator 52 are connected in parallel with each other. In the case, when said actuator 52 comprises more than one fuse 524, the fuses 524 are connected parallel with each other. Similarly, when said actuator 52 comprises more than one electromagnetic switch 525, all available switches 525 are also connected parallel with each other.

[0036] In addition, said actuator 52 comprises an electric initiating member 521′, 521″ in each of the disposable pyroswitches 5′, 5″ of the pyroswitch assembly 5, wherein said initiating member 521′, 521″ is suitable for initiating an explosive chemical reaction of at least one chemical reactant contained therein by means of an electric impulse.

[0037] Furthermore, said actuator 52 comprises an actuating member 522′, which is available in each of the disposable pyroswitches 5′, 5″ of the pyroswitch assembly 5, which is during said chemical reaction of the reactant after the activation of said initiating member 521 moveable in the direction towards the interrupting member 51 for ensuring the movement of the interrupting member 51 from its first position in contact with the primary conductor 11 and apart from the secondary conductor 12 into its other position, in which it is in indirect or direct contact with the secondary conductor 12.

[0038] The interrupting member 51′ of each previous pyroswitch 5′, the initiating member 521′ of which is electrically connected with the circuit 523 of said actuator 52, is by means of the actuating member 522′ moveable from its uninterrupted position when predetermined conditions are met to another position, in which the corresponding branch 112′ through the said pyroswitch 5′ is interrupted and the interrupting member 51′ is after the movement in an electrically conductive contact with the initiating member 521″ of each subsequent pyroswitch member 52′, while in the last pyroswitch member 5″, the interrupting member 51″, is moveable into another position, in which the respectable branch 112″ through said final pyroswitch 5″ is interrupted, in which it is placed into a direct electrically conductive contact with the secondary conductor 12.

[0039] At least one additional conductor 526 is optionally connected to said electric circuit 523, by means of which said circuit 523 is then connected with at least one external sensor 526′, so that in a critical situation, e.g. in a vehicle crash situation, said actuator 52 may be via said additional conductor 526 provided with a signal, which is required for initiating the displacement of each interrupting member 51′, 51″ and which is received from said external sensor 526′, which is suitable for monitoring electric current within a certain circuit, or from any other sensor, which is suitable for monitoring at least one further physical characteristic and which is available in a desire location in the vehicle or apparatus, in which said switch assembly 1 is installed.

[0040] Furthermore, at least one of the interrupting members 51′, 51″ may be mechanically interruptible from its initial position to another position corresponding through the pyroswitch 5′, 5″ passing branch 112′, 112″ of the second branch 112 of the primary electric conductor 11.

[0041] In the embodiment shown in the Figures, the interrupting member 51″ of the last pyroswitch, in the present embodiment 5″, in each pyroswitch assembly 5 in its second, that is, interrupted position, in which the electric circuit through all branches 112′, 112″ of the second branch 112 of the primary electric conductor 11 of the switch assembly 1 is interrupted, is brought into an electrically conductive contact with the secondary conductor 12 of the switch assembly 1 and indirectly also in electric contact with any electric load 3, as well as with the secondary terminal 22 of the direct voltage electric source 2 as shown in FIGS. 3 and 4.

[0042] Each electrical initiating member 521′ is on one hand connected to said circuit 523 of the actuator 52 and on the other hand with the initiating member 521″ of each subsequent pyroswitch 5′, 5″ in the pyroswitch assembly 5, wherein the initiating member 521″ of the last pyroswitch 5″ in the pyroswitch assembly 5 is electrically connected with the secondary conductor 12 of the electric circuit, in which the switch assembly 1 is integrated.

[0043] The electric resistance of the first branch 111 of the primary electric conductor 11 is much higher than the electric resistance of the second branch 112, 112′, 112″, which results in most of the electric current passing through the second branch 112, 112′, 112″ during regular operation of the electric circuit. In practice because of the electric fuse 4 with its melting member 41, the electric resistance of the first branch 111 may in some embodiments be more than 95% higher than the electric resistance of the second branch 112 with the second branch 112 being less than 5% of the total electric resistance of the primary electric conductor 111.

[0044] As shown in FIG. 2, when the initiating member 521′ in the area of the first pyroswitch 5′, when the predetermined conditions in the electric circuit 523 are met, triggers the actuating member 522′ and causes the movement of the interrupting member 51′ of the first pyroswitch 5′ into contact with the initiating member 521″ of the further pyroswitch 5″, the electric circuit is redirected from the newly interrupted branch 112′ through the further available branch 112″ and the pyroswitch 5″. In case of—again when predetermined conditions are met—the activation of the initiating member 521″ of the second pyroswitch 5″ in the electric circuit 523, the actuating member 522″ triggers the movement of the interrupting member 51″ of the second pyroswitch 5″ (FIG. 2) into electric contact with the initiating member of a yet further, subsequent pyroswitch, then it is available. In the exemplary embodiment, only two pyroswitches 5′, 5″ are foreseen, which means that after the activation of the initiating member 521″ the interrupting member 51″ of the second pyroswitch 5″ is moved into contact with the secondary conductor 12 of the electric circuit, in which the switch assembly 1 according to the invention is integrated. Persons of ordinary skill in the art can understand how to add additional pyroswitches to the disclosed embodiment to use three or more within switch assembly 1.

[0045] According the present disclosure the pyroswitch assembly 5 may be comprised of an array of pyroswitches 5′, 5″, connected into the electric circuit and arranged in the previously described manner and as shown in the accompanying Figures, the interruption of the electric circuit may be executed gradually and in series of multiple steps, depending on the number of pyroswitches 5′, 5″ in the pyroswitch assembly 5, which in practice enables the use of the switch assembly 1 in circuits which are exposed to high values of direct electric current including values that may exceed 400 A.

[0046] The switch assembly 1 according to the disclosure is no doubt simple and is despite to introduction of appropriate pyroswitch 5 not bulky in view of required space. Thanks to arrangement of said pyroswitch 5 and the electric fuse 4 with its melting member 41 into two separate branches 111, 112 of primary electric conductor 11 such switch assembly 1 is capable to withstand temperature variations of temperature variations and is moreover able to deal with inductivity variations of inductivity as well as dynamic current intensity, i.e. frequently changing of electric current values within each particular direct voltage (DC) electric circuit. On the other hand, said switch assembly 1 enables a prompt interruption of said direct voltage electric circuit on the basis of activation of the actuator 52, e.g. in situation of motor vehicle crash, regardless to each electric voltage and actual value of the electric current, and in particular without establishing an electric arc in the area of the pyroswitch assembly 5. Each disposable electric load(s) become(s) completely insulated with regard to each disposable direct voltage electric source 2. Thanks to said displacement of each interrupting member 51′, 51″ from its original i.e. uninterrupted position into its shifted position in contact with the secondary conductor 12 in each direct voltage circuit, via said switch assembly 1 and each load 3 an additional electric circuit is established, which is completely separated from the electric voltage source 2, and although any additional electric sources remain isolated within such newly established circuit, such sources cannot be brought in contact with the electric source 2.

[0047] The present disclosure may enable automatic activation of the switch assembly 1 when pre-determined requirements are met. To this aim, said actuator 52 of said pyroswitch 5 is via said interrupting member 51 connectable with the secondary conductor 12 of the switch assembly 1 and comprises in the area of each of the pyroswitches 5′, 5″ an electric initiating member 521′, 521″, in proximity to which an actuating member 522′, 522″ is arranged, as well as an electric circuit 523, which will be one by one explained in more detail.

[0048] Each electric initiating member 521′, 521″ is suitable for initiation of explosive chemical reaction in each corresponding pyroswitch 5′, 5″ of the pyroswitch assembly 5 of at least one chemical reactant contained therein by means of an electrical impulse, wherein the chemical structure of said chemical reactant can correspond to those, which is used in pyro-switches which are known in the prior art.

[0049] Each actuating member 522′, 522″ is during said chemical reaction of said reactant upon activation of each corresponding initiating member 521′, 521″ displaceable in a direction towards each corresponding interrupting member 51′, 51″ just in order to assure displacement of each interrupting member 51′, 51″ from its initial position in contact with the primary conductor 11 and apart from the secondary conductor 12 into its secondary position in contact with the initiating member 521″ of each subsequent pyroswitch 5″ and in the case of a final pyroswitch member 5″ with the secondary conductor 12 itself.

[0050] Said electric circuit 523 is in addition to said parallel branches 111, 112 integrated in said primary electric conductor 11 in such a manner, that it is connected with said electric voltage source 2 and said load 3 in serial with said branches 111, 112 of the primary conductor 11. In this, said electric circuit 523 consists of at least one irreversible thermal electric fuse 524 with a contact member 524′, which is during the regular operation of the switch assembly 1 interrupted and is closed i.e. set into uninterrupted state only when an electric overload occurs, as well as of at least one electromagnetic reed switch 525 with an interrupting member 525′, which is during regular operation of the switch assembly 1 interrupted and is closed i.e. set into uninterrupted state only when a pre-determined value of the electric current within the switch assembly 1 is exceeded. Said fuse 524 of the actuator 52 and said electromagnetic switch 525 of the actuator 52 are connected parallel with each other.

[0051] Also in the case, when said actuator 52 comprises more than one fuse 524, each disposable fuses 524 are connected parallel with each other, and quite similarly, whenever said actuator 52 comprises more than one electromagnetic switch 525, then each disposable switches 525 are also connected parallel with each other.

[0052] The electric initiating member 521 is connected both with said electric circuit 523 and with at least one additional electric conductor 526, which is suitable for establishing interconnection with at least one external sensor 526′.

[0053] A further embodiment is also possible, in which said actuator (52) can be in critical situation, e.g. in a vehicle crash situation, provided with a signal, which is required for initiation of displacement of the interrupting member (51) and which is via said additional conductor 526 received from said external sensor 526′, which is suitable for monitoring electric current values within certain circuit, or from any other sensor, which is suitable for monitoring of at least one further physical value and which is available in a desired location in a motor vehicle or other similar apparatus, in which said switch assembly 1 is installed.

[0054] Among other methods, activation of such switch assembly may be generally performed either by exceeding current overload or in a short circuit situation.

[0055] Activation by exceeding current may be performed by means of said irreversible thermal electric fuse 524, which is arranged in a heat conductive contact with conductive components of the switch assembly. By increasing the electric current, the temperature is also increasing, and each activation conditions can be defined in advance on the basis of suitable dimensioning or choice of the fuse 524. As soon as the electric current becomes higher than a pre-determined nominal value, conductive components of the pyro-switch start heating, and the fuse 524 with its contact member 524′ is also heated. As soon as a pre-determined temperature is reached, the contact member 524′ of the fuse 524 is shifted and the electric circuit through the fuse 524 is established i.e. uninterrupted, and the electric current starts flowing there-through, which is however limited with resistance of the actuator 52, so that in the case of overload said pyroswitch 5 is activated, so the interrupting member 51 is by means of actuator 52 shifted from its initial position in contact with the primary conductor 11 into its secondary position in contact with the secondary conductor 12.

[0056] Activation in a short circuit situation may be performed by means of said electromagnetic reed switch 525, which is sensible to the external magnetic field and is capable to react within extremely short time period, e.g. within 50 μs. Said time period may be shorter when a higher current is present and correspondingly higher magnetic field strength. Such short activation i.e. triggering time period needs to be achieved in particular due to current withstanding of the pyroswitch in the short circuit conditions. Said electromagnetic reed switch is arranged at a distance apart from conductive components of the pyroswitch 5′, 5″, and each condition, in which the electromagnetic switch 525 is reacting to short circuit overload, can also be determined in advance on the basis of adjusting the position of said switch 525, since the sensitivity i.e. reactiveness of said switch 525 is reciprocally proportional to the distance from the source of electromagnetic field. When in a short circuit situation the electric current starts to increase, the electromagnetic field is generated, which impacts the electromagnetic reed switch 525. At a predetermined magnetic field strength the contact members 525′ in the electromagnetic switch 525 are brought in contact with each other, and the circuit suitable for conducting electric current is herewith established within said switch 525. The current is also in this situation determined i.e. limited by resistance of the actuator 52, and by overloading i.e. by short circuit said pyroswitch 5′, 5″ is activated, so that by means of said actuator 52 each interrupting member 51′, 51″ is shifted from its initial position in contact with the primary conductor 11 into its secondary position in contact with each subsequent pyroswitch 5″ and the secondary conductor 12.