CN110867350A

CN110867350A - Passive triggering mechanism for a switching device comprising a pyrotechnic feature

Info

Publication number: CN110867350A
Application number: CN201910797822.XA
Authority: CN
Inventors: 默里·斯特凡·麦克蒂格; 丹尼尔·沙利文; 迈克尔·亨利·莫利纽克斯
Original assignee: Gigavac LLC
Current assignee: Gigavac LLC
Priority date: 2018-08-27
Filing date: 2019-08-27
Publication date: 2020-03-06
Also published as: GB202301229D0; GB2612232A; KR102604621B1; DE102019122961A1; GB2577984A; GB2612233A; GB2612233B; JP2020064847A; GB201912283D0; GB202301226D0; KR20200024114A; GB2577984B; GB2612232B; JP7405534B2

Abstract

The present invention relates to a passive triggering mechanism for a switching device comprising a pyrotechnic feature. Disclosed herein are passive trigger mechanisms for activating pyrotechnic features within electrical switching devices (e.g., contactor devices and fuse devices). Activation of the pyrotechnic feature is configured to change the configuration of internal components of the switching device and prevent current flow through the device. In some embodiments, the trigger mechanism includes a feature that is responsive to a magnetic field, such as a reed switch. In some embodiments, the reed switch responds to the elevated current and then a signal with the elevated current can be used to activate the pyrotechnic feature. In other embodiments, the reed switch uses a power signal from the auxiliary power source to activate the pyrotechnic feature.

Description

Passive triggering mechanism for a switching device comprising a pyrotechnic feature

Technical Field

Devices related to trigger mechanisms and configurations for electrical switching devices (e.g., contactor devices and electrical fuse devices) are described herein.

Background

Connecting and disconnecting circuits are as old as the circuit itself and are commonly used as a method of switching a power source to a connected electrical device between "on" and "off" states. An example of one device commonly used to connect and disconnect an electrical circuit is a contactor that is electrically connected to one or more devices or power sources. The contactor is configured so that it can open or complete an electrical circuit to control power to and from the device. One conventional contactor is a hermetically sealed contactor.

In addition to contactors used to connect and disconnect circuits during normal operation of the device, various additional devices may be employed to provide overcurrent protection. These devices can prevent short circuits, overloads and permanent damage to the electrical system or connected electrical devices. These devices include a disconnect device that can quickly disconnect the circuit in a permanent manner so that the circuit will remain open until the disconnect device is repaired, replaced, or reset. One such disconnect device is a fuse. A conventional fuse is a low resistance resistor that acts as a sacrificial device. A typical fuse includes a metal wire or strip that melts when an excessive current flows through it, thereby breaking the circuit to which it is connected.

As society advances, various innovations for electrical systems and electronic devices are becoming more prevalent. Examples of such innovations include recent advances in electric vehicles, which may become an energy conservation standard and replace traditional petroleum-powered vehicles for one day. In such expensive and conventionally used electrical devices, overcurrent protection is particularly useful to prevent device failure and to prevent permanent damage to the device. In addition, overcurrent protection can prevent safety hazards, such as electrical fires. These modern improvements to electrical systems and devices require modern solutions to increase the convenience and efficiency of the mechanism that triggers the fuse device.

Disclosure of Invention

Passive trigger components and configurations for activating a pyrotechnic feature for use as a fuse mechanism within a switching device (e.g., a contactor or fuse device) are described herein. These passive triggering configurations may be configured to trigger in response to a threshold magnetic field strength corresponding to a threshold level of current flowing through the device corresponding to a dangerous overcurrent. The current threshold level required to trigger these passive trigger configurations may be related to the distance between the passive trigger mechanism (e.g., a reed switch) and a portion of the device (e.g., a power terminal or feature connected to a power terminal).

One embodiment of an electrical switching apparatus according to the present invention includes a housing having an internal component configured to change a state of the switching apparatus from a closed state that allows current to flow through the switching apparatus to an open state that interrupts current flowing through the switching apparatus. A pyrotechnic feature is included that is configured to interact with the internal component to transition the switching device from the closed state to the open state when the pyrotechnic feature is activated. Also included is a passive trigger switch structure configured to activate the pyrotechnic feature when the passive trigger switch structure is triggered, the passive trigger switch structure configured to trigger in response to an elevated current signal flowing through the switching device. The passive trigger switch is further arranged to activate the pyrotechnic feature using the boosted current signal.

One embodiment of an electrical system according to the present invention includes an operating power supply circuit including an operating power supply coupled to an operating load through a current path with a contactor between the power supply and the load. Comprising a pyrotechnic activation circuit comprising a trigger arranged to sense an elevated current in the working power supply circuit, the activation circuit further comprising a pyrotechnic actuator that activates the pyrotechnic actuator to operate on the contactor to open a current path in the working power supply circuit.

One embodiment of the pyrotechnic activation circuit according to the invention comprises a trigger arranged to sense a magnetic field in dependence on the rising current in the circuit. Including a pyrotechnic actuator, wherein a trigger activates the pyrotechnic actuator in response to an elevated current level to open a circuit carrying the elevated current, wherein the trigger activates the pyrotechnic actuator using the elevated current.

These and other further features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, taken in conjunction with the accompanying drawings, in which like numerals represent corresponding parts in the several views, and in which:

drawings

FIG. 1 is a front cross-sectional view of an embodiment of a contactor that can incorporate features of the present invention, shown in the "closed" orientation allowing current to flow through the device;

FIG. 2 is a front cross-sectional view of an embodiment of the contactor device of FIG. 1, shown in an "open" or "disconnect" direction to prevent current flow through the device;

FIG. 3 is a front cross-sectional view of an embodiment of the contactor device of FIG. 1, shown in a different orientation, wherein the disconnect element has been "fired";

FIG. 4 is a front cross-sectional view of a fuse device that can incorporate features of the present invention, shown in a resting "unfired" state;

FIG. 5 is a front cross-sectional view of a fuse device that can incorporate features of the present invention, shown in an activated "triggered" state;

FIG. 6 is a front, top perspective view of a pyrotechnic trigger configuration incorporating features of the invention;

FIG. 7 is a rear, top view of the pyrotechnic trigger configuration of FIG. 6;

FIG. 8 is a front, top perspective view of another pyrotechnic trigger configuration incorporating features of the invention;

FIG. 9 is a rear, top view of the pyrotechnic trigger configuration of FIG. 8;

FIG. 10 is a front, top perspective view of yet another pyrotechnic trigger configuration incorporating features of the invention;

FIG. 11 is a front cross-sectional view of a portion of the pyrotechnic trigger configuration of FIG. 10;

FIG. 12 is a schematic diagram of one embodiment of a pyrotechnic power switching circuit in accordance with the present disclosure;

and

figure 13 is a schematic diagram of another embodiment of a pyrotechnic power switching circuit in accordance with the present invention.

Detailed Description

The present disclosure will now set forth a detailed description of various embodiments. These embodiments illustrate passive switching features and configurations for use with switching devices, such as contactors or fuse devices, that incorporate pyrotechnic circuit interrupting features. These switching devices may be electrically connected to electrical devices or systems to "turn on" or "turn off" the power supply to the connected devices or systems. While the example apparatus disclosed herein may utilize an active triggering configuration to supplement or replace the disclosed passive features, the passive features provide the advantage of automatically triggering the opening of a pyrotechnic circuit in response to a threshold current level.

In some embodiments, a Printed Circuit Board (PCB) or an external trigger mechanism is configured to direct a signal to a pyrotechnic pin in communication with a pyrotechnic charge. The power of this signal for triggering the pyrotechnic feature of the switching device may be provided by a separate power source (i.e. a power source other than the power source of the device or electrical system to which the switching device is connected). Alternatively, the power for the signal may be provided or transferred from a power source of the device or electrical system to which the switching device is connected. The pyrotechnic charge is configured to act as a fuse, permanently breaking the circuit by a contactor or fuse device, for example by moving a movable contact out of contact with a fixed contact.

The PCB or external trigger mechanism comprises a passive trigger switch, such as a reed switch, which opens in its quiescent state, preventing a trigger signal from being sent to the pyrotechnic pin and thus allowing current to flow through the device. The passive trigger switch may be configured to trigger in response to a magnetic field of sufficient strength that may be calculated to correspond to a desired threshold current level through the device, e.g., a dangerous overcurrent. Since the threshold strength of the magnetic field required to trigger the passive trigger switch depends on the proximity of the passive trigger switch to the magnetic field source, the passive trigger switch may be configured as a "proximity switch". This allows setting the desired trip current based on the distance between the passive trigger switch and an area of the device, such as one of the power terminals.

In other embodiments, additional features may be included. For example, the iron core structure may be positioned at least partially around one power terminal of the switching device, and the trip current may be determined by the distance between the core structure and the passive trigger switch. In some embodiments, an external trigger mechanism may be utilized, which may include a conductive bus portion and a passive trigger switch separated from the conductive bus portion by a non-magnetic spacer portion. In these embodiments, the trip current may be determined by the thickness of the non-magnetic spacer portion.

Throughout this specification, the preferred embodiments and examples shown should be considered as exemplars, rather than as limitations on the present invention. As used herein, the terms "invention," "device," "present invention," or "existing device" refer to any one of the embodiments of the invention described herein, as well as any equivalents. Furthermore, reference throughout this document to various features of the "invention," "apparatus," "invention," or "existing apparatus" does not mean that all claimed embodiments or methods must include the referenced features.

It will also be understood that when an element or feature is referred to as being "on" or "adjacent to" another element or feature, it can be directly on or adjacent to the other element or feature or intervening elements or features may also be present. It will also be understood that when an element is referred to as being "attached," "connected," or "coupled" to another element, it can be directly attached, connected, or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly attached," "directly connected," or "directly coupled" to another element, there are no intervening elements present.

Relative terms such as "outer," "above," "below," "under," "horizontal," "vertical," and similar terms may be used herein to describe one feature's relationship to another feature. It will be understood that these terms are intended to encompass different orientations than those depicted in the figures.

Although the terms first, second, etc. may be used herein to describe various elements or components, these elements or components should not be limited by these terms. These terms are only used to distinguish one element or component from another element or component. Thus, a first element or component discussed below could be termed a second element or component without departing from the teachings of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes" and/or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Embodiments of the invention are described herein with reference to different views and illustrations that are schematic illustrations of idealized embodiments of the invention. Accordingly, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Embodiments of the present invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing.

It will be understood that when a first element is referred to as being "on," "sandwiched" or "sandwiched" between two or more other elements, the first element can be directly between the two or more other elements or intervening elements may also be present between the two or more other elements. For example, if a first element is "between" or "sandwiched between" a second element and a third element, the first element may be directly between the second element and the third element without intervening elements, or the first element may be adjacent to one or more additional elements, both the first element and these additional elements being between the second and third elements.

Before describing in detail the particular pyrotechnic trigger configuration incorporating features of the invention, an example switching arrangement incorporating pyrotechnic features and providing an example environment for a passive trigger configuration in accordance with the invention will first be described. These switching devices may include any switching device that includes a pyrotechnic feature, such as a contactor configured to allow the device to switch between "on" and "off states.

In some contactor devices, a pyrotechnic feature is used as a fuse element incorporated into the contactor device. An example of such a Contactor Device is set forth in U.S. application No. 16/101,143 entitled "Contactor Device integrated pyrotechnic Disconnect contacts", which is assigned to Gigavac, inc. In addition to contactors configured to freely switch between "on" and "off states, pyrotechnic trigger configurations in accordance with the present disclosure may also be used with sacrificial fuse devices configured to allow current to pass through an electrical system or device when not triggered and to prevent current from passing through the electrical system or device when triggered. An example of such a fuse device is set forth in U.S. application No. 15/889,516, entitled "mechanical fuse device (MECHANICAL FUSE DEVICE)", which is assigned to Gigavac, inc, the assignee of the present application, and which is incorporated herein by reference.

Referring to an exemplary contactor device including a pyrotechnic feature, fig. 1 illustrates a cross-sectional view of an exemplary embodiment of a contactor device 100, the contactor device 100 including an integrated pyrotechnic disconnect feature that may function as a sacrificial disconnect in the event of an overcurrent. Fig. 1 shows the contactor device 100 in a "closed" circuit position, wherein current flow through the contactor device is initiated. Fig. 1 also shows the pyrotechnic opening portion of the contactor device 100 in its non-firing or "set" mechanical orientation, allowing the contactor device to function normally to operate between its "closed" and "open" positions. The open portion of the contactor device 100 also has a "trigger" direction in which the circuit is open and current through the contactor device is permanently disabled until the device is replaced or repaired and reset. The "close" and "open" contactor modes and the "set" and "toggle" open modes are all described in further detail herein.

The contactor device 100 of fig. 1 includes a body 102 (also referred to as a housing 102), and two or more fixed contact structures 104, 106 (two shown) configured to electrically connect internal components of the contactor device to an external circuit, such as to an electrical system or device. The body 102 may comprise any suitable material capable of supporting the structure and features of the contactor device 100 as disclosed herein, with the preferred material being a strong material that can provide structural support to the contactor device 100 without interfering with the flow of electricity through the fixed

contacts

104, 106 and the internal components of the device. In some embodiments, the body 102 comprises a durable plastic or polymer. The body 102 at least partially surrounds various internal components of the contactor device 100, which will be described in further detail herein.

The body 102 may include any shape suitable for housing various internal components, including any regular or irregular polygon. The body 102 may be a continuous structure or may comprise multiple components joined together, including, for example, a base "cup" and a top "head" portion sealed with an epoxy material. Some exemplary body configurations include those set forth in U.S. patent nos. 7,321,281, 7,944,333, 8,446,240, and 9,013,254, all assigned to Gigavac, inc, the assignee of the present application, and all of which are incorporated herein by reference in their entirety.

The fixed

contacts

104, 106 are configured such that various internal components of the contactor device 100 housed within the body 102 may be in electrical communication with an external electrical system or device such that the contactor device 100 may be used as a switch to open or complete an electrical circuit as described herein. The

stationary contacts

104, 106 may include any suitable electrically conductive material for providing electrical contact with internal components of the contactor device, such as various metals and metallic materials or any electrical contact material or structure known in the art. The fixed

contacts

104, 106 may include a single continuous contact structure (as shown) or may include multiple electrical connection structures. For example, in some embodiments, the fixed

contacts

104, 106 may include two portions, a first portion extending from the body 102 that is electrically connected to a second portion inside the body 102 that is configured to interact with other components inside the body as described herein.

The body 102 may be configured such that the interior space of the body 102 that houses the various internal components of the contactor device 100 is hermetically sealed. Such a hermetically sealed configuration may help mitigate or prevent arcing between adjacent conductive elements when coupled with the use of an electronegative gas, and in some embodiments, help provide electrical isolation between spatially separated contacts. In some embodiments, the body 102 may be under vacuum conditions. The body 102 may be sealed using any known means of creating a hermetically sealed electrical device. Some examples of hermetic seals include those described in U.S. patent nos. 7,321,281, 7,944,333, 8,446,240, and 9,013,254, all assigned to Gigavac, inc, the assignee of the present application, and all of which are incorporated herein by reference in their entirety.

In some embodiments, the body 102 may be at least partially filled with an electronegative gas, such as sulfur hexafluoride or a mixture of nitrogen and sulfur hexafluoride. In some embodiments, body 102 comprises a material that is low permeable or substantially impermeable to the gas injected into the housing. In some embodiments, the body may include various gases, liquids, or solids configured to increase the performance of the device.

Before describing the pyrotechnic disconnect features of the contactor device 100 for overcurrent protection, the contactor components used during ordinary switching use of the contactor device 100 will first be described. When not interacting with any other components inside the body 102, the fixed

contacts

104, 106 are instead electrically isolated from each other such that electricity cannot flow freely between them. The fixed

contacts

104, 106 may be electrically isolated from each other by any known electrical isolation structure or method.

When the contactor device 100 is in its "closed" position, as shown in fig. 1, both electrically isolated fixed

contacts

104, 106 are in contact with the movable contact 108. The movable contact 108 acts as a bridge to allow electrical signals to flow through the device, e.g., from the first fixed contact 104 to the movable contact 108, to the second contact 106, and vice versa. Thus, the contactor device 100 may be connected to an electrical circuit, system or device and complete the electrical circuit while the movable contact is in electrical contact with the fixed contact.

The movable contact 108 may include any suitable electrically conductive material, including any of the materials discussed herein with respect to the

stationary contacts

104, 106. As with the fixed

contacts

104, 106, the movable contact 108 may comprise a single continuous structure (as shown), or may comprise multiple components electrically connected to one another so as to act as a contact bridge between the electrically isolated fixed

contacts

104, 106 so that electricity may flow through the contactor device 100.

The movable contact 108 may be configured such that it may move into and out of electrical contact with the fixed

contacts

104, 106. This causes the circuit to "close" or complete when the movable contact is in electrical contact with the fixed

contacts

104, 106, and to "open" or open when the movable contact 108 is not in electrical contact with the fixed

contacts

104, 106. The fixed

contacts

104, 106 are electrically isolated from each other when not contacting the movable contact. In some embodiments, including the embodiment shown in fig. 1, the movable contact 108 is physically connected to a shaft structure 110, the shaft structure 110 being configured to move along a predetermined distance within the contactor device 100. The shaft 110 may comprise any material or shape suitable for its characteristics as an internal movable component that is physically connected to the movable contact 108 such that the movable contact 108 may move with the shaft 110.

As described herein, movement of the shaft 110 controls movement of the movable contact 108, which in turn controls the position of the movable contact 108 relative to the fixed

contacts

104, 106, which in turn controls the flow of electrical current through the contactor device 100. The movement of the shaft may be controlled by various configurations, including but not limited to electrical and electronic, magnetic and solenoid, and manual. An exemplary manual configuration for controlling a shaft connected to a movable contact is set forth in U.S. patent No. 9,013,254 to Gigavac, inc, the assignee of the present application, and all of which are incorporated herein by reference in their entirety. Some example configurations of manual control features include magnetic configurations, diaphragm configurations, and bellows configurations.

In the embodiment shown in fig. 1, the movement of the shaft 110 is controlled by using a solenoid configuration. The plunger structure 111 is connected to a portion of the shaft 110 or at least partially surrounds a portion of the shaft 110. The body 102 also houses a solenoid 112. Many different solenoids may be used, one example of a suitable solenoid being a solenoid that operates at a low voltage and a relatively high force. One example of a suitable solenoid is the commercially available solenoid model number SD 1564N 1200 from Bicron, inc, although many other solenoids may be used. In the illustrated embodiment, the plunger structure 111 may comprise a metallic material that is movable and controllable by the solenoid 112. Movement of the plunger structure 111 controls movement of the connecting shaft 110, which in turn controls movement of the connected movable contact 108, the connecting shaft 110.

The travel distance of the shaft 110 may be controlled using various features, such as springs for controlling the trip/extra-trip distance or various portions of the body 102 that may block or limit the travel distance of the shaft 110. In the embodiment shown in fig. 1, the travel distance of the shaft 110 is controlled in part by a hard stop 113, which hard stop 113 is configured to abut a wing portion 114 of the shaft 110 to limit the distance of the shaft 110 when the shaft 110 has traveled a sufficient distance from the fixed

contacts

104, 106. Hard stop 113 may comprise any material or shape suitable to provide a surface for interaction with shaft 110 to limit the travel of shaft 110. In the embodiment shown in FIG. 1, hard stop 113 comprises a plastic material. In some embodiments, the hard stop 113 is configured to break or shear when the pyrotechnic disconnect element is triggered, which will be discussed in further detail below.

Having now set forth the basic switching features of the contactor device 110, the pyrotechnic disconnect element will now be described. The contactor device 100 may include several elements that may be used as overcurrent protection, including a pyrotechnic charge 202 and a piston structure 204. The piston structure 204 may be positioned adjacent to or at least partially around one or more internal components, such as the shaft 110 as shown. Movement of the piston from the rest position may change the configuration of the internal components to break the current flow through the device, for example, by pushing or otherwise moving the shaft 100, as described herein. The pyrotechnic charge 202 may be configured such that it is activated when the current exceeds a predetermined threshold level to prevent permanent damage to a connected electrical device or a safety hazard such as an electrical fire.

The contactor device 100 may include various sensor features that may detect when the current through the device has reached a dangerous level and may trigger a pyrotechnic charge upon detection of the threshold level. In some embodiments, the contactor device 100 may include a dedicated current sensor configured to detect the level of current flowing through the device. The current sensor may be configured to directly or indirectly activate the pyrotechnic charge when the current reaches a threshold level. In some embodiments, when a threshold current level is detected, the current sensor may send a signal proportional to the detected current to activate the pyrotechnic charge. In some embodiments, the current sensor may comprise a hall effect sensor, a transformer or current clamp, a resistor, a fiber optic current sensor, or an interferometer.

In some embodiments, the pyrotechnic charge 202 is configured to be activated by an electrical pulse and driven by an airbag system configured to detect a number of factors, similar to those used in modern vehicles. In some embodiments, the contactor device 100 may include one or more pyrotechnic pins 203, which may be configured to trigger the pyrotechnic charge 202 when the pyrotechnic pin 203 receives an activation signal. In some embodiments, the pyrotechnic charge may be connected to another component that has been monitored for flow current. The other component, such as the battery management assembly, may then be configured to send a signal to activate the pyrotechnic charge upon detection of the threshold current level.

Pyrotechnic charge 202 may be a single charge configuration or a multiple charge configuration. In some embodiments, pyrotechnic charge 202 includes a dual charge configuration that includes first an initiator charge and then a second gas generant charge. As described herein, many different types of pyrotechnic charges may be used if the pyrotechnic charge used is sufficient to provide sufficient force to move the piston structure 204 to permanently break the electrical circuit of the contactor device 100. In some embodiments, the pyrotechnic charge 202 includes zirconium perchlorate, which has the advantage of being suitable for use as an initiator charge and a gas generant charge. In some embodiments, the initiator charge includes a fast-burning material, such as zirconium perchlorate, zirconium tungsten perchlorate, titanium potassium perchlorate, potassium hydrogen perchlorate, or potassium hydrogen perchlorate. In some embodiments, the gas generant charge includes a slow burning material, such as potassium boron nitrate or black powder.

When the pyrotechnic charge 202 is activated, the resulting force causes the piston structure 204 to be driven away from its rest position near or about the pyrotechnic charge 202, which in turn causes the piston structure 204 to push against the shaft 110 and the shaft to be driven away from the fixed

contacts

104, 106. The force generated is also sufficient to break or shear the hard stop 113, causing the shaft 110 to be forced further away from the fixed

contacts

104, 106, e.g., into a separate internal compartment 206 of the body 102. The piston structure 204 may include sufficient dimensions (e.g., shape, size, spatial orientation, or other configuration) such that the piston structure 204 may hold the internal components in place or in a configuration in which current cannot flow through the contactor device. This is accomplished, for example, by holding the shaft 110 in a position away from the fixed

contacts

104, 106, such as by holding the shaft 110 so that it is substantially within a separate interior compartment 206 of the body 102. This in turn causes the movable contact 108 connected to the shaft 110 to be separated from the fixed

contacts

104, 106 by an even greater spatial gap, leaving the device in a "triggered" or permanently "open" configuration in which electricity cannot flow through the device. In some embodiments, the piston structure 204 includes sufficient dimensions such that once it is displaced by activating the pyrotechnic feature 202, the piston structure 204 is forced into a position to interact with a portion of the body 102 such that it is not easily moved.

Other configurations may be used in addition to the large spatial gap that is rapidly created between the fixed

contacts

104, 106 and the movable contact 108. For example, in some embodiments, one or more arc ejecting magnets 208 (two shown) may be utilized to further control the arc. While the primary method for breaking the current is to open the contacts to a larger air gap quickly as described herein, additional performance can also be obtained by secondary gas explosion against the arc, for example, by using a gas generator charge.

In some embodiments, including the embodiment shown in figure 1, other optional design features may be included that may help prevent the danger of rapid accumulation of gas due to activation of the pyrotechnic charge 202. In these embodiments, the body 102 may be configured such that when the pyrotechnic charge 202 is activated, the piston structure 204 drives the shaft 110 with sufficient force to pierce a portion of the body 102. This will allow a rapid build-up of gas to escape. In some embodiments, this is achieved by a portion of the body 102 that includes a membrane that can be pierced during a pyrotechnic disconnect cycle, for example, by a sharp portion 210 of the shaft 110, allowing gas to escape from a connected vent portion 212 of the body 102, which may be a high temperature filter membrane. The high temperature gas may then be exhausted from the body 102. Pressure relief can cool the arc and improve performance and prevent the contact housing from cracking.

The difference between the circuit breaking the current through the contactor device 100 during normal switching operation and the permanent breaking of the circuit breaking the current through the contactor device 100 when the device is in its "trigger" state is better illustrated in fig. 2-3. Fig. 2-3 illustrate the contactor device 100 of fig. 1, but in a different orientation. The contactor device 100 includes a body 102, fixed

contacts

104, 106, a movable contact 108, a shaft 110, a plunger structure 111, a solenoid 112, a hard stop 113, a wing portion 114 of the shaft 110, a pyrotechnic charge 202, a thermal pin 203, a piston structure 204, a separate compartment 206 of the body 102, an arc blow-off magnet 208, a sharp portion 210 of the shaft 110, and a vent portion 212 of the body 102.

The contactor device 100 is shown in its "open" state in fig. 2, which shows the shaft 110 moving such that the connected movable contact 108 is separated from the fixed

contacts

104, 106 by an open space gap 302. As shown in fig. 2, the contactor device 100 is still in the "set" position without activating the pyrotechnic feature. The open space gap 302 separates the movable contact 108 from the fixed

contacts

104, 106 by a sufficient distance that the contacts would otherwise be electrically isolated from each other to break the current through the device. Conversely, fig. 3 shows the contactor device 100 in its triggered state when the pyrotechnic charge 202 is activated such that the piston structure 204 forces the shaft 110 and the movable contact 108 in a direction away from the fixed contact 104. This quickly creates a large open circuit space gap 350 between the fixed

contacts

104, 106 and the movable contact 108.

As shown in fig. 3, the force generated by activation of pyrotechnic charge 202, and the resulting sudden movement of piston structure 204 and shaft 110, is sufficient to fracture or shear hard stop 113 to displace from its original position of connection with body 113. Hard stop 113 may comprise a strong material that is coupled to or integrated with body 102 such that it acts as a stop for shaft 110 during normal device operation between "closed" and "open" circuit states. However, during operation of the pyrotechnic disconnect feature, the hard stop 113 may be intentionally designed to "fail" as a stop feature and to break or shear to allow the shaft 110 to enter the separate body compartment 206.

In some embodiments, the piston structure 204 may be configured such that it may interact with the piston stop portion 352 of the body 102 after activation of the pyrotechnic charge 202. This may be accomplished, for example, by interacting with the position of the piston structure 204, e.g., a portion of the piston stop portion 352 is configured to interact or mate with another portion on the piston structure 204.

In some embodiments, the piston structure 204 will not be in contact with the piston stop portion 352 until the piston structure 204 has been displaced by activation of the pyrotechnic charge 202. This results in the piston structure 204 being held between the piston stop portion 352 and the movable contact 108 when the pyrotechnic charge 202 has been activated and the piston structure 204 is forced from its rest position. As shown in fig. 3, this configuration places the piston structure 204 in a position that retains or locks the piston structure 204 to the movable contact 108. The piston structure 204 holds the movable contact 108 in place and helps to maintain the circuit opening space gap 350 so that the fixed

contacts

104, 106 and the movable contact 108 do not slide back into contact with each other so that the contactor device 100 is inoperable.

In some embodiments, instead of or in addition to piston stop portion 352 of body 102, individual compartments 206 of body 102 may include sufficient dimensions, including for example, dimensions and shapes, such that individual compartments 206 may interact with a portion of shaft 110 that has moved into individual compartments 206 as a result of activation of pyrotechnic charge 202.

In some embodiments, a separate compartment may be configured to interact with a sheared hard stop 113 or another structure coupled to shaft 110, which shaft 110 has moved into separate compartment 206 as a result of activation of pyrotechnic charge 202. During normal device operation, these portions of the shaft 110 or connection structure are not previously within the individual compartments 206, but are forced into the individual compartments 206 during a pyrotechnic cycle during over-current protection operation. The individual compartments 206 include sufficient size, shape, or additional features, for example, features configured to interact or mate with corresponding features on the shaft 110 or the connecting structure to hold the shaft 110 in place so that the movable contacts 108 connected to the shaft 110 cannot slide back into contact with the fixed

contacts

104, 106.

In addition to the foregoing features, the contactor device 100 of fig. 1-3 may also include a PCB 400. As will be discussed further herein, the PCB allows for efficient and convenient connection of the internal components of the contactor device 100 to a pyrotechnic trigger configuration incorporating features of the invention. PCB 400 may be a PCB designed to accommodate a pyrotechnic trigger configuration incorporating features of the invention. In the embodiment shown in fig. 1-3, the PCB 400 is shown positioned near the top of the contactor device 100; however, it should be understood that the PCB 400 may be located in or on any portion of the contactor device 100, and may be internal to the contactor device 100 or external to the contactor device 100.

In addition to contactor devices that may operate during normal operation to limit or allow current flow through the device, another type of switching device that may be used as an example environment for use with passive pyrotechnic trigger configurations is a fuse device. The fuse device only allows current to flow through the device during normal operation and acts as a sacrificial circuit open when a threshold current level is passed through the device. Fig. 4-5 illustrate an example fuse device 430 that includes similar features and operates similarly to the contactor device 100 of fig. 1-3, however, does not include some of these features, such as solenoids or other mechanisms for opening and closing fixed and movable contacts. During normal operation, the fuse device 430 is always in a "closed" state, allowing current to flow through the device until the pyrotechnic feature is activated, causing the device to thereafter be in an "open" state, preventing current from flowing through the device. Fig. 4-5 illustrate a body 432 (similar to the body 102 of fig. 1-3 above), stationary contacts 434, 436 (similar to the

stationary contacts

104, 106 of fig. 1-3 above). However, in this embodiment, the fixed

contacts

434, 436 are formed separately from the

power terminals

438, 440, the

power terminals

438, 440 being electrically connected to the fixed

contacts

434, 436 for connection to an external circuit, the power terminals and the fixed contacts being the same as in the embodiment of fig. 1 to 3. Fig. 4-5 further illustrate a movable contact 442 (similar to the movable contact 108 of fig. 1-3 above), a shaft structure 444 (similar to the shaft structure 110 of fig. 1-3 above, except for the different shapes).

The shaft structure 444 is connected to the movable contact 442 and the plunger structure 446 (which is similar to the plunger structure 204 in fig. 1-3 above). The piston structure 446 may at least partially surround the pyrotechnic charge 448 such that when the pyrotechnic charge 448 is activated, the movable contact 442 and the piston structure 446 are forced in a direction away from the fixed

contacts

434, 436, thus opening the electrical circuit. In some embodiments, the fuse apparatus 430 may include a support structure 450, the support structure 450 configured to help hold the fixed

contacts

434, 436 and the movable contact 442 in place. In some embodiments, triggering the pyrotechnic charge 448 causes the piston structure 446 to be driven away from the pyrotechnic charge in such a way that the support structure 450 is broken or displaced. In some embodiments, fuse device 430 may be triggered by an active signal. In some embodiments, fuse device 430 may be triggered by a passive triggering configuration, such as those discussed herein. Fig. 4 shows the fuse device 430 in a "closed" state, in which the fixed

contacts

434, 436 and the movable contact 442 are together and allow current to flow through the device 430. In contrast, fig. 5 shows the fuse device 430 in its "open" state after the pyrotechnic charge 448 is triggered, wherein the fixed

contacts

434, 436 and the movable contact 444 are separated and prevent current flow through the device 430.

Since two types of switching devices, contactors and fuse devices have been described as example environments in which a pyrotechnic trigger mechanism in accordance with the present disclosure may be utilized, embodiments of the pyrotechnic trigger mechanism may now be described more fully. In the following embodiments described in relation to fig. 6 to 11, the pyrotechnic trigger configuration will be described with reference to the contactor device applied to fig. 1 to 3. It should be understood, however, that the pyrotechnic trigger arrangements described in relation to figures 6 to 11 may be applied as a trigger device in any switching mechanism incorporating pyrotechnic features, including for example the fuse device described in relation to figures 4 to 5.

Fig. 6 shows a pyrotechnic trigger configuration 500 that includes a PCB502 (traces not shown), similar to PCB 400 in fig. 1-3, power terminals 504, similar to

fixed contact structures

104, 106 in fig. 1-3, and a passive trigger switch 506. Fig. 6 also shows a pyrotechnic trigger arrangement 500 integrated with an electrical device 503, which includes a body 508, which body 508 may be similar to body 102, containing internal components. The pyrotechnic trigger arrangement 500 in fig. 6 is shown without the top "cap" portion of the body, such that the PCB502 is visible and exposed, however, it will be appreciated that in normal device operation, components such as an enclosed body comprising a cap and an epoxy material may be included. Figure 6 also shows a pyrotechnic pin 510, similar to the pyrotechnic pin 203 of figures 1-3. A coil pin 512 is included that allows electrical connection to an internal coil or solenoid, e.g., similar to solenoid 112 in fig. 1-3. Also included is a tubular structure 514 that may help form an internal hermetic seal or management of the electronegative gases within electrical device 503.

In operation of the pyrotechnic trigger configuration 500 of fig. 6, the passive trigger switch 506 will be activated when a predetermined level of current is passed through the device 503, for example, a current level indicative of a dangerous current level may result in permanent damage to the device or create a hazard such as a fire. This in turn completes the circuit that transmits a signal to the pyrotechnic pin 510 to activate an internal pyrotechnic element, such as, for example, the pyrotechnic charge 202 of figures 1-3. In these embodiments, the PCB502 may be configured such that it directs the trigger signal to the pyrotechnic pin 510, the pyrotechnic pin 510 being in electrical communication with a pyrotechnic feature internal to the device 503. The electrical path of the trigger signal may be dependent on closing or activating the passive trigger switch 506 such that when the passive trigger switch 506 is open or not triggered (in a quiescent state), the electrical path of the trigger signal to the pyrotechnic pin 510 is blocked. Likewise, when the passive trigger switch 506 is closed or activated, a trigger signal may be directed to the pyrotechnic pin 510 and trigger an internal pyrotechnic feature.

The passive trigger switch 506 may be connected to a sensor configured to detect when a predetermined level of current passes through the device 503, the sensor signals the passive trigger switch 506 to trigger. In some embodiments, the passive trigger switch 506 itself is configured to detect or passively respond and trigger when the current flowing through the device 503 reaches a predetermined level. For example, in some embodiments, the passive trigger switch 506 comprises a switch configured to react to a magnetic field generated by a current flowing through the power supply terminal 504 of the apparatus 503 or a current passing through a region of the apparatus 503.

In some implementations, the passive trigger switch 506 is a reed switch or other switching mechanism configured to activate in response to generating a magnetic field of sufficient strength. The reed switch can use different configurations. For example, the reed switch may be configured such that the contacts open at rest, close when a sufficient magnetic field is present, or close at rest and open when a sufficient magnetic field is present. Further, in some embodiments, the reed switch may be organized as a reed relay and actuated by a magnetic coil. In most embodiments incorporating a reed switch herein, the reed switch is configured such that the contacts open at rest, preventing an electrical signal from traveling to the pyrotechnic pin 510 and activating the pyrotechnic feature until a sufficient magnetic field corresponding to the hazardous current level closes the reed switch.

In some embodiments, the PCB502 includes a plurality of passive trigger switch mounting features 516 that allow the pyrotechnic trigger configuration 500 to be adjusted according to a desired trip current. For example, fig. 7 shows a pyrotechnic trigger configuration 500, a PCB502, an electrical device 503, a power terminal 504, a passive trigger switch 506, a body 508, a pyrotechnic pin 510, a coil pin 512, a tubular structure 514, and a trigger switch mounting feature 516. As shown in fig. 7, the desired trip current can be adjusted by mounting the passive trigger switch 506 to a different one of the trigger switch mounting features 516, which in turn adjusts the trip distance 518 between the passive trigger switch 506 and the one or more power terminals 504.

By adjusting the trip distance 518 between the passive trigger switch 506 and the one or more power terminals 504, the amount of current flowing through the device 503, which is required to activate the passive trigger switch 506, and thus trigger the internal pyrotechnic features of the device, may be adjusted. For example, the passive trigger switch 506 may include a reed switch configured to activate when a predetermined magnetic field is generated due to a predetermined current level flowing through the power supply terminal 504. The strength of the magnetic field required to trigger the passive trigger switch 506, and thus the level of corresponding current through the device required to trigger the passive trigger switch 506, can be adjusted by simply changing the trip distance 518 between the passive trigger switch 506 and the power supply terminal 504. In the illustrated embodiment, this may be accomplished by mounting the passive trigger switch 506 to a different passive trigger switch mounting feature 516.

By moving the passive trigger switch 506 away from the power supply terminal 504, a larger magnetic field and therefore a larger current will be required to trigger the passive trigger switch 506 and thus the pyrotechnic feature of the device 503. This may provide a pre-designed switching device with a pre-designed PCB such that the device may be mass manufactured while allowing different trip currents to be placed at different ones of the passive trigger switch mounting features 516 based on the passive trigger switch 506. For example, the passive trigger switch mounting features 516 may be on the PCB502 at locations corresponding to different levels of magnetic field strength, which in turn may correspond to different levels of desired trip current. Companies may manufacture one PCB configuration and may place the passive trigger switch 506 on different passive trigger switch mounting features 516 to create a device that will trip at different currents. In embodiments utilizing a coil or solenoid, the passive trigger switch 506 may be configured to turn off power to the coil, such as with a contactor. In these embodiments, this configuration may reduce the time it takes for the pyrotechnic feature to open the contacts, as it does not have to resist the coil.

In other embodiments, additional features may be included in place of or in addition to the trigger switch mounting features 516 to further interact with the passive trigger switch 506. For example, fig. 8 shows a device 602 having a pyrotechnic trigger configuration 600 similar to the pyrotechnic trigger configuration 500 of fig. 6 and 7. The device 603 includes a PCB 602 (similar to PCB502 in fig. 7), an electrical device 603 (similar to electrical device 503 in fig. 7), and a power terminal 604 (similar to power terminal 504 in fig. 7). Device 603 also includes a passive trigger switch 606 (similar to passive trigger switch 506 in fig. 7), a body 608 (similar to body 508 in fig. 7), a pyrotechnic pin 610 (similar to pyrotechnic pin 510 in fig. 7), a coil pin 612 (similar to coil pin 512 in fig. 7), and a tubular structure 614 (similar to tubular structure 514 in fig. 7). While similar embodiments may include a trigger switch mounting feature, the embodiment shown in fig. 8 does not include a trigger switch mounting feature. Instead, the pyrotechnic trigger configuration 600 includes a core structure 630 that facilitates determining a target trip current for the pyrotechnic trigger configuration 600.

Core structure 630 may comprise any known material capable of directing, or controlling the magnetic field generated by the current flowing through device 603. For example, in some embodiments, core structure 630 comprises a metal. In some embodiments, the core structure 630 comprises iron, an iron alloy, or other ferrous material. In some embodiments, the core structure 630 is magnetic. Core structure 630 may include any suitable shape or configuration that produces the desired magnetic field characteristics, including any regular or irregular polygon or custom shape. In the embodiment shown in fig. 8, the core structure 630 comprises a curved strip shape. The core structure 630 may be configured in any spatial location relative to the device 603 and the PCB 602 to facilitate interaction between the generated magnetic field and the passive trigger switch 606. In the embodiment shown in fig. 8, the core structure 630 at least partially surrounds one of the power terminals 604 and is adjacent to the passive trigger switch 606.

The magnetic field generated from the core structure 630 may be more important than the magnetic field generated by the power supply terminal itself, and the desired trigger current may be controlled by adjusting the distance between a portion of the core structure 630 and the passive trigger switch 606, rather than from the power supply terminal 604 and the passive trigger switch 606 as in the embodiments of fig. 6-7. For example, fig. 9 shows a pyrotechnic trigger configuration 600, a PCB 602, an electrical device 603, a power terminal 604, a passive trigger switch 606, a body 608, a pyrotechnic pin 610, a coil pin 612, a tubular structure 614, and a core structure 630. Fig. 9 also shows the trip distance 636 between the passive trigger switch 606 and the core structure 630. Similar to the embodiments of fig. 7-8, the passive trigger switch 606 may include a reed switch or other passive mechanism configured to activate when a predetermined magnetic field is generated due to a predetermined current level flowing through the power supply terminal 604 and/or the core structure 630.

The strength of the magnetic field required to trigger the passive trigger switch 606, and thus the level of the corresponding current flowing through the device required to trigger the passive trigger switch 606, can be adjusted by simply changing the trip distance 636 between the passive trigger switch 606 and a portion of the core structure 630. By moving the passive trigger switch 606 away from the core structure 630, a larger magnetic field, and therefore a larger current, will be required to trigger the passive trigger switch 606, and therefore the pyrotechnic feature of the device 603.

In some embodiments, an external trigger mechanism may be used instead of or in addition to trigger switch mounting feature 606 or core structure 630. In some embodiments, the external trigger mechanism may replace the need for a PCB, but in other embodiments, an external trigger mechanism may be used in addition to a PCB. An example embodiment is shown in fig. 10, where an external trigger mechanism replaces the need for a PCB. Fig. 10 shows a pyrotechnic trigger configuration 700 (similar to the pyrotechnic trigger configuration 600 of fig. 8). Configuration 700 includes an electrical device 703 (similar to electrical device 603 in fig. 8), a power terminal 704 (similar to power terminal 604 in fig. 8), a passive trigger switch 706 (similar to the passive trigger switch in fig. 8), a body 708 (similar to body 608 in fig. 8), a pyrotechnic pin 710 (similar to pyrotechnic pin 610 in fig. 8), an access point 712 (which may provide line access to an internal solenoid or coil), and a tubular structure 714 (similar to tubular structure 614 in fig. 8). Fig. 10 also shows the body 708 including a top or cap portion 716 through which the power terminals 704 protrude.

It should be understood that a similar top or cap portion of cap portion 716 of body 708 shown in fig. 10 may be applied to all other embodiments incorporating features of the present invention. For example, it should be understood that the device embodiments of fig. 6 and 8 are shown without the cap portion to better illustrate the underlying PCB configuration. However, during final assembly, the embodiment of fig. 6 and 8 may have all internal components completely enclosed within the body and including the cap portion of the body.

The embodiment of fig. 10 also shows an external trigger mechanism 730 that includes a passive trigger switch 706, a conductive bus bar 732, and a spacer portion 734. As shown in fig. 10, the conductive bus bar 732 may include a plurality of connection portions, wherein the conductive bus bar 732 in the illustrated embodiment includes a first connection point 736 and a second connection point 738, the first connection point 736 being configured to connect to the device 708 at one of the power terminals 704, and the second connection point 738 being configured to connect to an external power source.

Conductive bus 732 may include any conductive material, such as a metallic material. In some embodiments, conductive bus bar 732 comprises copper. The spacer portion 734 may include a non-magnetic material. The conductive bus 732 may be configured to allow current to flow to the pyrotechnic pin 710 and thereby trigger internal pyrotechnic features of the device 703. Similar to the passive trigger switch in the embodiment shown in fig. 6 and 8, the passive trigger switch 706 is configured in an open state that does not allow current to pass through the conductive bus 732 and thus allows the pyrotechnic feature to be triggered.

When the current from the device 703 reaches a threshold level, a sufficient magnetic field is generated to trigger the passive trigger switch 706. This allows current from an external power source connected to the second connection 738 of the conductive bus bar 732 to flow through the conductive bus bar 732 to the pyrotechnic pin 710 and thereby trigger the pyrotechnic feature of the device.

The threshold magnetic field required to activate the passive trigger switch 706 may be adjusted by adjusting the distance between the passive trigger switch 706 and the conductive bus 732, and thus determining the current level required to be sufficiently dangerous to warrant activation of the pyrotechnic circuit opening feature. This may be accomplished, for example, by adjusting the thickness of the non-magnetic spacer portion 734. For example, fig. 11 shows a close-up cross-sectional view of external trigger mechanism 730 of fig. 10, including passive trigger switch 706, conductive bus bar 732, and spacer portion 734, first connection point 736, and second connection point 738. Fig. 11 also shows a trip distance 750, which corresponds to the thickness of the non-magnetic spacer portion 734.

Similar to the embodiments discussed above, the passive trigger switch 706 may include a reed switch or other passive mechanism. The switch may be configured to activate when a predetermined magnetic field is generated due to a predetermined current level flowing through the power supply terminal 604, in which case the power supply terminal 604 is electrically connected to an external trigger mechanism. The strength of the magnetic field required to trigger the passive trigger switch 706, and thus the level of corresponding current flowing through the device 703 required to trigger the passive trigger switch 706, can be adjusted by simply changing the trip distance 750 between the passive trigger switch 706 and the conductive bus bar 732. By increasing the thickness of the non-magnetic spacer portion 734, and thus moving the passive trigger switch 706 away from the conductive bus bar 732, a greater magnetic field, and thus a greater current, will be required to trigger the passive trigger switch 706 and thus the pyrotechnic feature of the device 703. Also by moving the passive trigger switch 706 closer to the conductive bus 732, a smaller magnetic field, and therefore less current, will be required to trigger the passive trigger switch 706 and thus the pyrotechnic feature of the device 703.

It should be understood that different pyrotechnic passive switching circuits may be arranged in many different ways in accordance with the invention. Figure 12 shows a simplified schematic diagram of one embodiment of a pyrotechnic passive switching circuit 800 in accordance with the present invention. The circuit 800 generally includes an operating power supply circuit 802 that includes a standard operating power supply 804 coupled to a workload 806, the workload 806 being powered and supplied by the power supply 802. A contactor or fuse 808 is disposed in the circuit 800 to break an electrical connection between the power source 804 and the load when a dangerous current flows in the circuit 802. It should be appreciated that the fuse 808 may also include a feature that acts as a contactor to disconnect the power source 804 from the load during normal operating conditions. It should also be understood that the fuse 808 may include a contactor, wherein the passive switching circuit 800 operates to change the state of the contactor to open the circuit path as described above.

A pyrotechnic activation circuit 810 may be included that is arranged to operate with the operational power supply circuit 802 to prevent an over-current condition. The circuit 810 includes a pyrotechnic actuator/activator 812 as described above, which is arranged to change the state of the fuse 808 upon activation. The circuit also includes an overcurrent-actuated pyrotechnic fuse trigger 814 disposed near the circuit 802 in a position that allows it to sense an overcurrent condition in the circuit 802. In the illustrated embodiment, trigger 814 may comprise a reed switch, but it should be understood that many different alternative devices may be used. Flip-flop 814 may be placed in many different locations relative to circuit 802, such as adjacent to power supply terminals as described above, or adjacent to other conductors in the circuit that carry operating current. The circuit 810 may also include an auxiliary power supply 816, and the auxiliary power supply 816 may be coupled to the pyrotechnic actuator 812 when the fuse trigger is turned off in response to the elevated current level.

During operation, the fuse 808 is closed, allowing the operating supply power 804 to power the load 806. When a normal current level flows through the circuit 802, the trigger 814 remains open and the auxiliary power supply 816 is disconnected from the pyrotechnic actuator 812. When current above a certain level (a dangerously high level) flows through circuit 802, flip-flop 814 closes in response to the rising magnetic field. This connects the secondary power source to the pyrotechnic actuator 812 causing it to actuate and open the fuse 808. This in turn disconnects the operating power supply 804 from the load 806 to break the conductive path for the elevated current in the circuit 802.

It will be appreciated that other circuits according to the invention may be arranged in many different ways with many different devices and elements. Many different auxiliary power sources may be used, with some embodiments using an integrated battery or capacitor circuit to store sufficient charge to activate the pyrotechnic actuator 812. In other embodiments, the auxiliary power source may comprise an onboard low voltage power source that is still sufficient to activate the pyrotechnic actuator 812.

Figure 13 illustrates another embodiment of a pyrotechnic passive switching circuit 900 in accordance with the present invention that incorporates many of the same features as the switching circuit 800 shown in figure 12. The circuit 900 includes an operating power supply circuit 902, the operating power supply circuit 902 including a standard operating power supply 904 coupled to a workload 906. A contactor or fuse 908 is disposed in the circuit 900 to break an electrical connection between the power source 904 and the load 906 when a hazardous current flows in the circuit 902.

The circuit 900 includes a pyrotechnic actuator/activator 912 and an overcurrent-actuated pyrotechnic fuse trigger 914 similar to those described above. However, in the circuit 900, these elements are not arranged in a separate pyrotechnic activation circuit that works with an auxiliary power source to activate the pyrotechnic actuator 912. Instead, these elements are integrated with the operating power supply circuit 902, and the flip-flop 914 is configured to sense the elevated current in the circuit 902 and is also coupled to the circuit 902 at the conductor carrying the elevated current. In the embodiment shown, the flip-flop 914 is coupled to the circuit conductor in parallel with the fuse 908, but it should be understood that it may be arranged in other ways.

During normal operation, the trigger 914 is turned on and power from the power supply 904 is conducted through the fuse 908 to the load 906. When the trigger 914 senses the elevated current, it closes and the elevated current passes through the trigger 914 to the pyrotechnic actuator 912, actuating the actuator and opening the fuse 908. This disrupts the normal conduction path between the power supply 904 and the load 908.

The trigger 914 is also arranged such that the elevated current from the power supply 904 quickly ruptures or otherwise destroys the trigger 914, thereby breaking the current path through the trigger 914. The trigger 914 carries a sufficiently long current to activate the actuator, but is destroyed shortly thereafter. This results in the power supply 904 being electrically isolated from the load 906 and any elevated current path being broken. It should be understood that trigger 914 and actuator 912 may have elements that contain them during rupture or activation, such as an encapsulating material like epoxy.

It will also be appreciated that elements of a circuit according to the invention may be coupled together using many different electrical conductors. This may include conductive paths or wires on the printed circuit board. It will also be appreciated that the above described circuit may be arranged on and integrated with the contactor or fuse to provide an easy to use and compact device. The circuit 900 may provide certain advantages, such as not requiring a separate auxiliary power source to activate the pyrotechnic actuator 912. This may result in a simplified and cheaper device.

Although the present invention has been described in detail with reference to certain preferred configurations thereof, other versions are possible. Embodiments of the invention may include any combination of compatible features shown in the various figures and should not be limited to those explicitly shown and discussed. Therefore, the spirit and scope of the present invention should not be limited to the above versions.

The foregoing is intended to cover all modifications and alternative constructions falling within the spirit and scope of the invention, in which no part of the disclosure is intended to be dedicated to the public domain, either explicitly or implicitly, unless otherwise stated in any claim.

Claims

1. An electrical switching apparatus comprising:

a housing;

an internal component within the housing configured to change a state of the switching device from a closed state that allows current to flow through the switching device to an open state that disconnects current flowing through the switching device;

a pyrotechnic feature configured to interact with the internal component to transition the switching device from the closed state to the open state when the pyrotechnic feature is activated;

a passive trigger switch structure configured to activate the pyrotechnic feature when triggered, the passive trigger switch structure configured to trigger in response to a magnetic field reaching a threshold strength when a threshold current level flows through the switching device; and

a power terminal electrically connected to the internal part to be connected to an external circuit.

2. The electrical switching apparatus of claim 1 wherein said passive trigger switch comprises a reed switch.

3. The electrical switching apparatus of claim 1 wherein said passive trigger switch is connected to a PCB.

4. The electrical switching apparatus of claim 3 wherein the threshold strength of the magnetic field is determined at least in part by a distance of the passive trigger switch from at least one of the power terminals.

5. The electrical switching apparatus of claim 4 wherein said PCB comprises a plurality of passive trigger switch mounting features.

6. The electrical switching apparatus of claim 5 wherein the plurality of passive trigger switch mounting features are configured at locations at different distances from at least one of the power terminals such that the locations correspond to different desired trigger thresholds based on different magnetic field threshold strengths.

7. The electrical switching apparatus of claim 3 further comprising at least one core structure.

8. The electrical switching apparatus of claim 7 wherein said core structure at least partially surrounds at least one of said power terminals.

9. The electrical switching apparatus of claim 8 wherein the threshold strength of the magnetic field is determined by a distance of the passive trigger switch from a portion of the at least one core structure.

10. An electrical switching apparatus comprising:

a housing;

a passive trigger switch structure configured to activate the pyrotechnic feature upon triggering, the passive trigger switch structure configured to trigger in response to an elevated current signal flowing through the switching device, the passive trigger switch being arranged to activate the pyrotechnic feature using the elevated current signal.

11. The electrical switching apparatus of claim 10 wherein said passive trigger switch comprises a reed switch.

12. The electrical switching apparatus of claim 10 wherein said passive trigger switch is connected to a PCB.

13. The electrical switching apparatus of claim 12 wherein said PCB comprises a plurality of passive trigger switch mounting features.

14. The electrical switching apparatus of claim 13 wherein the plurality of passive trigger switch mounting features are configured at locations at different distances from at least one of the power terminals such that the locations correspond to different desired trigger thresholds based on different magnetic field threshold strengths.

15. The electrical switching apparatus of claim 10 further comprising a power supply terminal, wherein the passive trigger switch is configured to trigger in response to an elevated current in the power supply terminal.

16. An electrical system, comprising:

a working power supply circuit comprising a working power supply coupled to a working load through a current path, a contactor being located between the power supply and the load;

a pyrotechnic trigger circuit including a trigger/switch arranged to sense an elevated current in the operating power supply circuit; and

a pyrotechnic actuator activated by the trigger/switch to run on the contactor to open the current path in the operating power supply circuit.

17. The system of claim 16, wherein the contactor includes internal components within a housing configured to change a state of a switching device from a closed state that allows current to flow through the contactor to an open state that opens current flowing through the contactor.

18. The system of claim 17, wherein the pyrotechnic actuator interacts with the internal component to transition the contactor from the closed state to the open state when the pyrotechnic actuator is activated.

19. The system of claim 17, wherein the trigger circuit uses the elevated current to activate the pyrotechnic actuator.

20. The system of claim 17, wherein the trigger circuit activates the pyrotechnic actuator using an auxiliary power source.

21. The system of claim 20, wherein the auxiliary power source comprises a battery, a capacitor circuit, or a low voltage power source.