Electrical circuit switching device

Abstract

This electric circuit switching device comprises: a housing; an igniter for releasing a combustion gas upon activation; a cylindrical space formed in the housing; an electrically conductive projectile that is positioned at a predetermined first position in the cylindrical space in an initial state; a piston fixed to the projectile and located in the cylindrical space so as to be interposed between the igniter and the projectile, said piston configured to be launched in a predetermined launching direction by the energy from the combustion gas; and a pair of first conducting strips provided in an inserted condition spaced apart from each other at a position in the cylindrical space farther in the launching direction than the first position. The projectile is launched together with the piston at the time of activation of the igniter and makes contact with each of the pair of first conducting strips, whereby a first electric circuit is switched from a cutoff state to a conducting state.

Description

Technical Field

[0001] The present invention relates to an electric circuit switching device.

Background Art

[0002] [[ID=!2]]There is known a relay that protects an electrical device by switching a specific electric circuit from an open state to a conductive state when an abnormality occurs in the electrical device. Conventionally, as a relay, an electromagnetic relay that switches the opening and closing of an electric circuit using an electromagnet is known. However, in the conventional electromagnetic relay, since it takes time to switch to the conductive state, there is a problem that a malfunction such as a failure of the electrical device due to the influence of an overcurrent occurs.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technology of the present disclosure provides a technology capable of shortening the time required for switching in an electric circuit switching device for switching a predetermined electric circuit from an open state to a conductive state.

Means for Solving the Problems

[0005] To solve the above problems, the electrical circuit switching device of this disclosure employs the following configuration. That is, the technology of the present disclosure is an electrical circuit switching device for switching a predetermined first electrical circuit from a disconnected state to a conductive state when in operation, comprising: a housing; an igniter provided in the housing and releasing combustion gas when in operation; a cylindrical space formed within the housing and extending in one direction; a conductive projectile positioned at a predetermined first position in the cylindrical space in an initial state before the igniter is activated; a piston fixed to the projectile and positioned in the cylindrical space so as to be interposed between the igniter and the projectile, and launched in a predetermined firing direction along the cylindrical space by the energy of the combustion gas; and a pair of first conductive pieces inserted at a position in the cylindrical space on the firing direction side of the first position, separated from each other, and each of the first conductive pieces cooperating to form a part of the first electrical circuit, wherein the projectile launched together with the piston when the igniter is activated contacts each of the pair of first conductive pieces, thereby switching the first electrical circuit from a disconnected state to a conductive state.

[0006] Furthermore, the electrical circuit switching device according to the present disclosure further comprises a pair of second conductor pieces inserted in the cylindrical space at a distance from each other, which can switch a predetermined second electrical circuit from a conductive state to a disconnected state when in operation, and which each second conductor piece cooperates to form a part of the second electrical circuit, wherein in the initial state, the pair of second conductor pieces are electrically connected via the projectile, causing the second electrical circuit to be in a conductive state, and when the projectile is launched in the launch direction, the electrical connection of the pair of second conductor pieces via the projectile is released, thereby switching the second electrical circuit from a conductive state to a disconnected state.

[0007] Furthermore, in the electrical circuit switching device according to this disclosure, the projectile is interposed between the pair of second conductor pieces in the initial state and these are connected together, and the projectile may be separated from each of the pair of second conductor pieces by the energy of the combustion gas.

[0008] Furthermore, in the electrical circuit switching device according to the present disclosure, the projectile has a base body positioned at the first position in the initial state, and a pair of projections extending from the base body toward the firing direction, and each of the pair of first conductor pieces is provided with an insertion hole into which the projections of the fired projectile can be inserted, and the first electrical circuit may be switched from an interrupted state to a conductive state by the projections coming into contact with the edges of the insertion holes.

[0009] Furthermore, in the electrical circuit switching device according to this disclosure, a wedge-shaped portion may be formed on the tip side of the projection.

[0010] Furthermore, the electrical circuit switching device according to this disclosure may be configured such that, when the projection is inserted into the insertion hole, the leg portion of the projection that is located closer to the base body than the wedge portion pushes open the insertion hole.

[0011] Furthermore, in the electrical circuit switching device according to this disclosure, the piston may be arranged in the cylindrical space in a manner that restricts its rotation around its axial direction. [Effects of the Invention]

[0012] The electrical circuit switching device described herein makes it possible to shorten the time required to switch a predetermined electrical circuit from an interrupted state to a conductive state. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a perspective view of the switching device according to Embodiment 1. [Figure 2] Figure 2 is a longitudinal cross-sectional view showing the state of the switching device according to Embodiment 1 before operation. [Figure 3] Figure 3 is a diagram illustrating the cylindrical space in the switching device according to Embodiment 1. [Figure 4] Figure 4 is a plan view of a pair of first conductor pieces according to Embodiment 1. [Figure 5] FIG. 5 is a diagram for explaining the conductor component according to Embodiment 1. [Figure 6] FIG. 6 is a longitudinal sectional view showing the state after the operation of the switching device according to Embodiment 1. [Figure 7] FIG. 7 is a longitudinal sectional view showing the state before the operation in the switching device according to Embodiment 2. [Figure 8] FIG. 8 is a longitudinal sectional view showing the state after the operation in the switching device according to Embodiment 2. [Figure 9] [[ID=H14]]FIG. 9 is a longitudinal sectional view before the operation of the switching device according to Embodiment 3. [Figure 10] FIG. 10 is a perspective view of the switching device according to Embodiment 4. [Figure 11] FIG. 11 is a longitudinal sectional view before the operation of the switching device according to Embodiment 4. [Figure 12] FIG. 12 is a diagram for explaining the conductor component according to Embodiment 4. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an electric circuit switching device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that each configuration in the embodiment and combinations thereof, etc. are examples, and within the scope not departing from the gist of the present disclosure, additions, omissions, substitutions, and other changes of the configuration can be made as appropriate. The present disclosure is not limited by the embodiments, but is limited only by the claims.

[0015] An electric circuit switching device according to an embodiment of the present disclosure is a device installed in an electric device (or electrical equipment) for quickly switching between a conductive state and a cutoff state (also referred to as a "non-conductive state") of an electric circuit. For example, when an abnormality occurs in an electric device to be installed, the electric circuit switching device according to the embodiment can be used as a short-circuit device that urgently switches a predetermined electric circuit from a "cutoff state" in which the electric circuit is cutoff to a "conductive state" in which the electric circuit is conductive, thereby short-circuiting the electric circuit. As another usage example of the electric circuit switching device according to the embodiment, it can be used as a switching device that cutoff a conductive electric circuit while making another cutoff electric circuit conductive. In this specification, the "conductive state" refers to a state in which an electric circuit is electrically connected and current can flow, and "cutoff" refers to a state in which an electric circuit is not electrically connected and current cannot flow.

[0016] <Embodiment 1> FIG. 1 is a perspective view of an electric circuit switching device (hereinafter simply referred to as a "switching device") 10 according to Embodiment 1. In this specification, a cross-section along the vertical direction shown in FIG. 1 is referred to as a longitudinal cross-section of the switching device 10, and a cross-section in a direction orthogonal to the longitudinal cross-section is referred to as a transverse cross-section of the switching device 10. FIG. 2 is a longitudinal cross-sectional view showing the state before operation of the switching device 10 according to Embodiment 1.

[0017] The switching device 10 includes a housing 1, an igniter 2 provided on the housing 1, a cylindrical space formed inside the housing 1, a piston 4 and a projectile 5 accommodated in the cylindrical space 3, a pair of first conductor pieces 6, 6 provided on the housing 1, a pair of second conductor pieces 7A, 7B provided on the housing 1, and the like. In the switching device 10, the state before the igniter 2 operates may be referred to as an "initial state".

[0018] [Housing] Housing 1 is an outer shell member that houses various parts and elements that constitute the switching device 10. Housing 1 is composed of a housing body 11 and a top holder 12 attached to the upper part of the housing body 11. The top holder 12 is made of metal, for example, and is an outer shell member having a stepped cylindrical shape as shown in Figure 1. The top holder 12 is composed of a small diameter portion 121 and a large diameter portion 122 that is connected below the small diameter portion 121. The upper end of the top holder 12 is an open end, and an igniter 2 is attached to the inner side of the small diameter portion 121 so as to airtightly close the open end. For convenience, the igniter 2 is not shown in Figure 1.

[0019] The housing body 11 is an outer shell member formed from an insulating material such as synthetic resin. For example, the housing body 11 may be made of nylon, which is a type of polyamide synthetic resin. In the example shown in Figures 1 and 2, the housing body 11 is composed of a combination of a top housing 111, a middle housing 112, and a bottom housing 113, but the embodiment is not particularly limited to this.

[0020] Figure 3 is a diagram illustrating the cylindrical space 3 formed within the housing 1 in the switching device 10 according to Embodiment 1. For convenience, the piston 4 and projectile 5 are not shown, and a longitudinal cross-section of the switching device 10 before operation is shown. In Figure 3, the pair of first conductor pieces 6A, 6B and the pair of second conductor pieces 7A, 7B are also not shown. As shown in Figure 3, a cylindrical space 3 extending in one direction is formed within the housing 1. The reference numeral CL in Figure 3 indicates the axis of the cylindrical space 3 extending in one direction within the housing 1. In this embodiment, the cylindrical space 3 extends in the vertical direction of the switching device 10 (housing 1). The piston 4 and projectile 5 are housed in the cylindrical space 3 formed in this way, as shown in Figure 2.

[0021] Furthermore, the reference numerals 114A and 114B shown in Figure 3 are first retaining holes for inserting and holding a pair of first conductor pieces 6A and 6B. Reference numerals 115A and 115B are second retaining holes for inserting and holding a pair of second conductor pieces 7A and 7B. The first retaining holes 114A and 114B are formed, for example, as recesses formed between the upper surface of the bottom housing 113 and the lower surface of the middle housing 112. The second retaining holes 115A and 115B are formed as recesses formed between the upper surface of the middle housing 112 and the lower surface of the top housing 111. The first retaining holes 114A and 114B and the second retaining holes 115A and 115B extend along the cross-sectional direction of the switching device 10 (housing 1). One end of the first retaining holes 114A and 114B communicates with the cylindrical space 3, and the other end is open to the outside of the housing 1. Similarly, one end of the second retaining holes 115A and 115B communicates with the cylindrical space 3, while the other end is open to the outside of the housing 1.

[0022] [Igniter] The igniter 2 is an ignition device that releases combustion gas into the cylindrical space 3 when in operation, and has, for example, an ignition section containing gunpowder in a cup-shaped body. The igniter 2 can be formed, for example, by an electric igniter. The gunpowder contained in the ignition section of the igniter 2 is not particularly limited, but for example, ZPP (zirconium potassium perchlorate), ZWPP (zirconium tungsten potassium perchlorate), THPP (titanium hydride potassium perchlorate), lead tricinate, etc. may be used. The igniter 2 may also have a conductive pin (not shown) connected to a connector of an external power supply, and the gunpowder may be ignited by an operating current supplied to the conductive pin from the external power supply. This type of electric igniter is well known, and for example, an electric igniter provided in the inflator of an airbag device can be suitably used. The ignition section of the igniter 2 is positioned facing into the cylindrical space 3. The igniter 2 releases the combustion gases generated by the burning of gunpowder into the cylindrical space 3 when it is activated.

[0023] [Projectile] The projectile 5 is formed from, for example, a conductive metal piece. As shown in Figure 2, the projectile 5 is housed within the cylindrical space 3 of the housing 1. In the initial state before the igniter 2 is activated, the projectile 5 is positioned at a predetermined first position P1 on the axis CL of the cylindrical space 3. As will be described in detail later, when the igniter 2 is activated, the projectile 5 is launched in a predetermined firing direction D1 along the axis CL of the cylindrical space 3 by the energy of the combustion gas released from the igniter 2 into the cylindrical space 3. In the example shown in Figure 2, the firing direction D1 is set downward along the axis CL of the cylindrical space 3. The projectile 5 can also be called a "bullet".

[0024] The projectile 5 consists of a base body 51 and a pair of projections 52A and 52B that protrude downward (towards the launch direction D1) from the base body 51. The projectile 5 can be described as a so-called fork-shaped bullet.

[0025] [piston] As shown in Figure 2, the piston 4 is initially positioned in the cylindrical space 3 so as to be interposed between the igniter 2 and the projectile 5. When the igniter 2 is activated, the piston 4 is launched in the aforementioned firing direction D1 by the energy of the combustion gas released from the igniter 2 into the cylindrical space 3.

[0026] The piston 4 has a generally cylindrical shape and is formed of an insulating material such as synthetic resin. In this embodiment, the piston 4 is configured, for example, to include a sliding portion 41 located at the upper end and a rod portion 42 connected below the sliding portion 41. The sliding portion 41 of the piston 4 has a diameter that roughly corresponds to the inner diameter of the large-diameter portion 122 of the top holder 12, and is guided along the inner wall surface of the large-diameter portion 122 when firing in the firing direction D1 during the operation of the igniter 2. This allows the piston 4 to move along the axis CL of the cylindrical space 3. The diameter of the sliding portion 41 of the piston 4 may be slightly smaller than the inner diameter of the large-diameter portion 122. Furthermore, the shape of the sliding portion 41 can be appropriately changed to match the shape of the inner wall surface of the large-diameter portion 122.

[0027] Furthermore, reference numeral 41A denotes a recess formed by a part of the upper surface of the sliding part 41 being recessed. In the initial state, a part of the ignition part of the igniter 2 is received in the recess 41A of the piston 4. Therefore, the energy of the combustion gas released from the igniter 2 during operation can be efficiently received by the recess 41A and efficiently utilized as thrust to fire in the firing direction D1.

[0028] Furthermore, the lower surface 41B of the sliding portion 41 of the piston 4 collides with the stopper portion 111A in the housing 1 (top housing 111) when the piston 4 is launched in the firing direction D1 during the operation of the ignition device 2, thereby restricting further movement of the piston 4 in the firing direction D1. However, the piston 4 is not limited to this configuration and can be of various forms.

[0029] Furthermore, a constricted portion, whose outer surface is recessed compared to other parts, is formed in an annular shape along the circumferential direction of the sliding portion 41 in the axial middle portion of the sliding portion 41 of the piston 4, and an annular packing (not shown) may be fitted into this constricted portion. This annular packing is made of, for example, rubber (e.g., silicone rubber) or synthetic resin, and functions to improve airtightness between the inner wall surface of the large diameter portion 122 and the sliding portion 41.

[0030] The rod portion 42 of the piston 4 has a cylindrical rod shape, for example, with a smaller diameter than the sliding portion 41. The lower surface (tip surface) 42A of the rod portion 42 is positioned to face the upper surface 51A of the base body 51 of the projectile 5. Therefore, when the igniter 2 is activated and the piston 4 is fired in the firing direction D1, the lower surface 42A of the rod portion 42 presses against the upper surface 51A of the base body 51 of the projectile 5. As a result, when the igniter 2 is activated, the energy of the combustion gas is transmitted to the projectile 5 via the piston 4, and the projectile 5 can be fired in the firing direction D1.

[0031] In this embodiment, the piston 4 and the projectile 5 are fixed (joined) together. More specifically, the lower surface 42A of the rod portion 42 of the piston 4 is bonded to the upper surface 51A of the base body 51 of the projectile 5, thereby integrating the piston 4 and the projectile 5. The specific method for integrating the piston 4 and the projectile 5 is not particularly limited; for example, screws may be used, or the piston 4 and the projectile 5 may be integrated by press-fitting.

[0032] [First conductor piece] Figure 4 is a plan view of a pair of first conductor pieces 6A and 6B according to Embodiment 1. Each of the first conductor pieces 6A and 6B has substantially the same structure. As shown in Figure 4, the pair of first conductor pieces 6A and 6B are conductors formed from rectangular metal plates. The pair of first conductor pieces 6A and 6B can be formed from a metal such as copper (Cu). However, the pair of first conductor pieces 6A and 6B may be formed from a metal other than copper, or from an alloy of copper and another metal. Examples of metals other than copper that may be included in the pair of first conductor pieces 6A and 6B include manganese (Mn), nickel (Ni), platinum (Pt), and the like.

[0033] The pair of first conductor pieces 6A and 6B are components of the switching device 10, and each of them works together to form a part of a predetermined first electrical circuit in the electrical equipment to which the switching device 10 is applied. The pair of first conductor pieces 6A and 6B are also called bus bars. The first electrical circuit is formed by including the pair of first conductor pieces 6A and 6B and other circuit components in the electrical equipment.

[0034] Each pair of first conductor pieces 6A and 6B has an insertion hole 63 on its inner end 61 side into which the projections 52A and 52B of the projectile 5 can be inserted, and a connection hole 64 on its outer end 62 side. The shape of the insertion hole 63 is not particularly limited, but in the example shown in Figure 4, it is formed as an elongated hole extending in the width direction of each first conductor piece 6A and 6B. The symbol W0 in Figure 4 is the opening width of the connection hole 64 in the short axis direction. The connection hole 64 is also used to connect to other conductors (e.g., lead wires) that form the first electrical circuit. The pair of first conductor pieces 6A and 6B are held in a state where they are inserted into a pair of first retaining holes 114A and 114B in the housing 1. In this case, as shown in Figure 2, each first conductor piece 6A and 6B is positioned in the pair of first retaining holes 114A and 114B with its inner end 61 side inserted into the cylindrical space 3 and its outer end 62 side exposed to the outside of the housing 1.

[0035] As shown in Figure 2, the bottom housing 113 has a support portion 116 for supporting the inner end 61 side of each first conductor piece 6A, 6B. As shown in Figure 2, the pair of first conductor pieces 6A, 6B in this embodiment are held in a pair of first retaining holes 114A, 114B in the housing 1, spaced apart from each other. The pair of first retaining holes 114A, 114B in the housing 1 and the support portion 116, supported by the first retaining holes 114A, 114B in the housing 1, are incorporated into the housing 1 so as to extend in a direction perpendicular to the axis CL of the cylindrical space 3, as shown in Figure 2. Also, as shown in Figure 2, in the initial state before the igniter 2 is activated, the pair of first conductor pieces 6A, 6B are positioned at a predetermined second position P2. The second position P2 is defined as a position on the firing direction D1 side of the first position P1 where the projectile 5 is positioned. Furthermore, a pair of recesses 117 are formed at the bottom of the bottom housing 113, facing the cylindrical space 3. These pair of recesses 117 are recesses for receiving the tip ends of the projections 52A and 52B of the projectile 5 that are fired when the igniter 2 is activated. In order to accommodate the projections 52A and 52B of the projectile 5, the cross-section of the recesses 117 is formed as an elongated hole shape that is slightly larger than the cross-section of the projections 52A and 52B.

[0036] As described above, the pair of first conductor pieces 6A and 6B are separated from each other before the ignitioner 2 is activated, as shown in Figure 2, and the first electrical circuit is kept in a disconnected state. On the other hand, although the operation of the switching device 10 will be described later, when the ignitioner 2 is activated, the pair of first conductor pieces 6A and 6B become electrically connected to each other via the projectile 5, and the first electrical circuit switches from a disconnected state to a conductive state. Therefore, in this embodiment, the projectile 5 can also be said to function as a circuit component constituting the first electrical circuit. Note that the reference numeral X1 in Figure 1 indicates the axis of arrangement of the pair of first conductor pieces 6A and 6B when they are assembled in the housing 1.

[0037] [Second conductor piece] Next, the pair of second conductor pieces 7A and 7B in this embodiment will be described. The pair of second conductor pieces 7A and 7B are components that make up the switching device 10, and each of them works together to form a part of a predetermined second electrical circuit in the electrical equipment to which the switching device 10 is applied. The pair of second conductor pieces 7A and 7B are also called bus bars. The second electrical circuit is formed by including the pair of second conductor pieces 7A and 7B and other circuit components in the electrical equipment.

[0038] In this embodiment, in the state before the igniter 2 is activated, i.e., the initial state, the pair of second conductor pieces 7A and 7B are electrically connected by the projectile 5 (see Figure 2). Specifically, a conductor component 8, in which the pair of second conductor pieces 7A and 7B and the projectile 5 are integrated, is provided in the housing 1.

[0039] Figure 5 illustrates the conductor component 8 according to Embodiment 1, and shows a plan view (top view), a cross-sectional view, and a side view of the conductor component 8. The cross-sectional view shows the AA section along the long axis of the conductor component 8. The side view shows the conductor component 8 viewed from the direction of arrow B.

[0040] As shown in Figure 5, the conductor component 8 is a metal body in which a projectile 5 is sandwiched between a pair of second conductor pieces 7A and 7B, and these are connected integrally. In the conductor component 8, the second conductor piece 7A, the projectile 5, and the second conductor piece 7B are arranged in a straight line. The material of the conductor component 8 is not particularly limited as long as it is a conductor, and the material used for the first conductor pieces 6A and 6B described above (for example, copper, etc.) can be suitably used. Note that the reference numeral X2 shown in Figure 1 is the alignment axis of the pair of second conductor pieces 7A and 7B when assembled in the housing 1. In this embodiment, the alignment axis X2 of the pair of second conductor pieces 7A and 7B is parallel to the alignment axis X1 of the pair of first conductor pieces 6A and 6B. Furthermore, the alignment axis X2 of the pair of second conductor pieces 7A and 7B is set to coincide with the longitudinal axis of the conductor component 8. Also, the AA cross section of the conductor component 8 is a cross section that passes through the longitudinal axis of the conductor component 8.

[0041] Next, the details of each part of the conductor component 8 will be described. The pair of second conductor pieces 7A and 7B are formed as conductor pieces extending in one direction, and the inner end 71 side of each is integrally connected to the base body 51 of the projectile 5. A connection hole 74 similar to that of the first conductor pieces 6A and 6B described above is formed on the outer end 72 side of each second conductor piece 7A and 7B. The connection hole 74 is used to connect to other conductors (e.g., lead wires) that form a second electrical circuit.

[0042] Reference numeral 81 denotes a connection portion to which each second conductor piece 7A, 7B is connected to the base body 51 of the projectile 5. A notch 82 is formed in the connection portion 81 of the conductor component 8 by beveling the surface of the component. By providing the notch 82 in this way, the thickness of the plate of the connection portion 81 is made thinner than that of other parts, resulting in a weaker connection portion compared to other parts. The notch 82 may be provided on either the upper surface or the lower surface of the conductor component 8, or on both. Of course, the shape of the notch 82 is not particularly limited and can be V-shaped, U-shaped, etc.

[0043] The projectile 5 has a pair of projections 52A and 52B protruding downward from the lower surface 51B of the base body 51. As shown in the cross-sectional and side views of Figure 5, the pair of projections 52A and 52B have a blade shape and are roughly corresponding to the elongated insertion holes 63 formed in the pair of first conductive pieces 6A and 6B. The pair of projections 52A and 52B in the projectile 5 configured as described above are erected vertically from the lower surface 51B of the base body 51, spaced apart from each other by a predetermined distance. In addition, a wedge-shaped wedge portion 521 is formed at the tip side (lower end side) of each projection 52A and 52B. A wedge shape is a shape that tapers towards the tip. Reference numeral 522 denotes the leg portion of the projections 52A and 52B that is located closer to the base body 51 than the wedge portion 521. The width dimension W1 of the leg portion 522 in the protrusions 52A and 52B is larger than the thickness dimension T1.

[0044] The conductor component 8, configured as described above, is assembled into the housing 1 such that a portion of the inner end 71 side of each second conductor piece 7A, 7B and the projectile 5 are housed in the cylindrical space 3, and the outer end 62 side of each second conductor piece 7A, 7B is exposed to the outside of the housing 1. At this time, the pair of second conductor pieces 7A, 7B of the conductor component 8 are held in the pair of second holding holes 115A, 115B of the housing 1, respectively. Furthermore, as shown in Figure 2, when the conductor component 8 is assembled into the housing 1, the base body 51 of the projectile 5 and each of the second conductor pieces 7A, 7B connected to the base body 51 are positioned to extend in a direction perpendicular to the axis CL of the cylindrical space 3. At this time, the position on the axis CL where the pair of second conductor pieces 7A, 7B are positioned is the same first position P1 as the base body 51 of the projectile 5. Furthermore, when assembling the conductive component 8 into the housing 1, the projectile 5 may be positioned such that the center of the base body 51 of the projectile 5 passes through the axis CL of the cylindrical space 3. In addition, in the initial state shown in Figure 2, the tip positions (lower end positions) of each projection 52A, 52B on the projectile 5 are positioned above the pair of first conductive pieces 6A, 6B, and the projectile 5 is separated from the pair of first conductive pieces 6A, 6B (non-contact state).

[0045] Furthermore, the symbols CL2 and CL3 shown in Figure 2 represent the axes of the projections 52A and 52B in the projectile 5. The axes CL2 and CL3 of the projections 52A and 52B are parallel to the axis CL of the cylindrical space 3, and their positional relationship is defined such that the central axes of the insertion holes 63 and recesses 117 in the pair of first conductive pieces 6A and 6B are located on axes CL2 and CL3.

[0046] Furthermore, when the igniter 2 is activated, the connecting portion 81 of the conductive component 8 is pushed through by the lower surface 42A of the rod portion 42 of the piston 4, and the projectile 5 is cut off. The symbol S1 in the figure is the planned fracture line, which indicates the position where the conductive component 8 is pushed through by the rod portion 42 of the piston 4 when the igniter 2 is activated. In the figure, the planned fracture line S1, shown as a dashed line, coincides with the contour position of the outer surface of the rod portion 42 of the piston 4, which is located on the upper part of the base body 51 of the projectile 5, when the conductive component 8 is assembled into the housing 1.

[0047] Furthermore, as shown in Figure 5, the conductor component 8 is provided with a pair of notches 83 that straddle each of the second conductor pieces 7A, 7B and the projectile 5. In other words, the pair of notches 83 are positioned to straddle the intended break line S1 in the conductor component 8. This reduces the area to be cut when the piston 4 (rod portion 42) cuts the projectile 5 from the conductor component 8 (each of the second conductor pieces 7A, 7B) when the igniter 2 is operated, enabling smooth cutting of the projectile 5.

[0048] [Operation] Next, the operation of the switching device 10 will be described. Before the switching device 10 is activated, it is in the initial state shown in Figure 2 as described above. In the initial state shown in Figure 2, the pair of first conductor pieces 6A and 6B are separated from each other, so the first electrical circuit, which is partially formed by this pair of first conductor pieces 6A and 6B, is kept in an interrupted state. On the other hand, in the above initial state, the pair of second conductor pieces 7A and 7B are electrically connected via the projectile 5, so the second electrical circuit is in a conductive state.

[0049] For example, when an abnormality occurs in the electrical equipment to which the switching device 10 applies, the switching device 10 operates to protect the electrical equipment and urgently switches the second electrical circuit from a conduction state to a disconnection state, and the first electrical circuit from a disconnection state to a conduction state.

[0050] The object to which the switching device 10 is applied is not particularly limited, but it may be installed in vehicles such as automobiles. For example, if the control unit of the vehicle's battery fails, the switching device may switch the second electrical circuit from a conductive state to a non-conductive state to cut off the power supply from the battery to the outside, thereby suppressing failure of external components due to overcurrent, and switch the first electrical circuit from a non-conductive state to a conductive state to discharge the charge accumulated in the second electrical circuit from the first electrical circuit, thereby protecting the second electrical circuit. Of course, the above-described examples of applications of the switching device 10 are just examples, and it may also be applied to other electrical equipment and electrical facilities other than vehicles.

[0051] The switching device 10 may further include an abnormality detection sensor (not shown) for detecting abnormal conditions in the electrical equipment on which the switching device 10 is installed, and a control unit (not shown) for controlling the operation of the igniter 2. The abnormality detection sensor may, for example, detect abnormal conditions such as overcurrent based on the current flowing through the electrical circuit to be protected in the electrical equipment. Alternatively, the abnormality detection sensor may be, for example, an impact sensor, a temperature sensor, an acceleration sensor, or a vibration sensor, which may detect abnormal conditions such as accidents or fires based on impact, temperature, acceleration, or vibration in equipment such as a vehicle.

[0052] The control unit of the switching device 10 is, for example, a computer that can perform predetermined functions by executing a predetermined control program. The predetermined functions performed by the control unit can also be realized by corresponding hardware. For example, if an overcurrent flows through the circuit to be protected in the electrical equipment on which the switching device 10 is installed, the overcurrent is detected by the abnormality detection sensor. Abnormality information regarding the detected abnormal current is passed from the abnormality detection sensor to the control unit. For example, based on the current value detected by the abnormality detection sensor, the control unit receives power from an external power supply (not shown) connected to the conductive pins of the igniter 2 and operates the igniter 2. Here, the overcurrent may be defined as a current value that exceeds a predetermined threshold set for the protection of the electrical circuit to be protected. Note that the abnormality detection sensor and control unit described above do not have to be included as components of the switching device 10, and may be included in a separate device, for example. Also, the abnormality detection sensor and control unit are not essential components of the switching device 10.

[0053] When the igniter 2 of the switching device 10 is activated, combustion gas is released from the igniter 2 into the cylindrical space 3. The piston 4, which receives the energy (pressure) of the combustion gas released from the igniter 2 at the recessed portion 41A of the sliding portion 41, uses the energy of the combustion gas as propulsion and is launched in the firing direction D1 (downward) within the cylindrical space 3. In the initial state, the projectile 5 of the conductive component 8 is positioned below the rod portion 42 of the piston 4, and the contour position of the lower surface 42A of the rod portion 42 is located at the connection portion 81 which is at the boundary between the projectile 5 of the conductive component 8 and each of the second conductive pieces 7A, 7B. Therefore, when the igniter 2 is activated, the piston 4 is forcefully pushed down in the firing direction D1, and the projectile 5 is separated from each of the second conductive pieces 7A, 7B at the connection portion 81. Then, the projectile 5 located below the rod portion 42 of the piston 4 is launched together with the rod portion 42 in the firing direction D1.

[0054] Figure 6 is a longitudinal cross-sectional view showing the switching device 10 according to Embodiment 1 after operation. As described above, the projectile 5 is separated from each of the second conductor pieces 7A and 7B by the energy of the combustion gas released from the igniter 2 via the piston 4, thereby electrically disconnecting the pair of second conductor pieces 7A and 7B from each other. As a result, the second electrical circuit, which is partially formed by the pair of second conductor pieces 7A and 7B, can be instantly switched from a conductive state to a disconnected state.

[0055] The projectile 5, launched along the axis CL in the firing direction D1 within the cylindrical space 3 together with the piston 4, is stretched between a pair of first conductor pieces 6A and 6B located at a lower second position P2, and makes contact with each of the pair of first conductor pieces 6A and 6B. More specifically, as shown in Figure 6, after the pair of projections 52A and 52B on the projectile 5 are inserted through the insertion holes 63 in the pair of first conductor pieces 6A and 6B, the tips of each projection 52A and 52B are received in the recess 117 of the housing 1. In this embodiment, when the projections 52A and 52B of the projectile 5 are inserted into the insertion holes 63 in each of the first conductor pieces 6A and 6B, the projections 52A and 52B are configured to make contact with the edges of the insertion holes 63. This allows the first electrical circuit to switch instantaneously from a disconnected state to a conductive state. In this embodiment, the projectile 5 has a pair of protrusions 52A and 52B on the base body 51, but it is of course possible to provide three or more protrusions. That is, the projectile 5 in this embodiment can have at least one pair of protrusions. If the projectile 5 has three or more protrusions on the base body 51, the first conductor pieces 6A and 6B can also be provided with a number of insertion holes 63 corresponding to the number of protrusions.

[0056] [effect] As described above, the switching device 10 according to Embodiment 1 uses the energy of the combustion gas generated by igniting the gunpowder in the igniter 2 as an energy source to operate the switching device 10, thereby firing a conductive projectile 5, and using the projectile 5 to switch the electrical circuit from a conductive state to a disconnected state, or from a disconnected state to a conductive state. By using pyrodynamics to operate the switching device 10 in this way, the time required to switch the electrical circuit can be shortened compared to, for example, a conventional electromagnetic relay.

[0057] Furthermore, the switching device 10 according to Embodiment 1 employs a so-called fork-shaped projectile 5. Therefore, the tips of each projection 52A, 52B can be brought closer to the pair of first conductor pieces 6A, 6B than the position of the base body 51 on the projectile 5, and the device can be incorporated into the cylindrical space 3 of the housing 1. This makes it possible to suitably reduce the distance between the projectile 5 and the first conductor pieces 6A, 6B in the initial state before the ignitioner 2 is activated, and further shorten the time required to switch the electrical circuit. However, due to structural reasons or other constraints, it may be difficult to position the first conductor pieces 6A, 6B and the second conductor pieces 7A, 7B held in the housing 1 very close together. Thus, even when it is difficult to set the first position P1, where the conductor component 8, which is an integrated unit of the pair of second conductor pieces 6A, 6B and the projectile 5, is initially positioned, and the second position P2, where the pair of first conductor pieces 6A, 6B are initially positioned, close together, the switching device 10 according to this embodiment allows for free adjustment of the lengths of the protrusions 52A, 52B on the projectile 5, and positions the tips of the protrusions 52A, 52B closer to the launch direction D1 than the first position P1. Therefore, even faster switching of electrical circuits becomes possible.

[0058] Furthermore, the switching device 10 according to Embodiment 1 incorporates a conductor component 8 into the housing 1 in which the base body 51 of the projectile 5 is interposed between a pair of second conductor pieces 7A and 7B and these are integrally connected. When the igniter 2 is operated, the energy of the combustion gas released from the igniter 2 separates the base body 51 from each of the pair of second conductor pieces 7A and 7B. This allows for a smooth switching of the second electrical circuit, which is partially formed by the pair of second conductor pieces 7A and 7B, from a conductive state to a disconnected state when the igniter 2 is operated.

[0059] Furthermore, in this embodiment, when the igniter 2 is activated, the projections 52A and 52B of the projectile 5 are inserted into the insertion hole 63, and the projections 52A and 52B are made to make reliable contact with the edge of the insertion hole 63, thereby enabling reliable switching to a conductive state of the first electrical circuit. In particular, by forming wedge-shaped wedge portions 521 on the tip side of each projection 52A and 52B of the projectile 5, the projections 52A and 52B can be smoothly inserted into the insertion hole 63 when the projectile 5 is fired.

[0060] Here, the thickness dimension T1 of the leg portion 522 of each projection 52A, 52B may be larger than the opening width W0 of the insertion hole 63 of each first conductor piece 6A, 6B. In this way, when the projectile 5 is launched, the leg portion 522 of each projection 52A, 52B can push open the insertion hole 63 and insert the leg portion 522 into the insertion hole 63. This ensures a more reliable contact between each projection 52A, 52B and the edge of the insertion hole 63.

[0061] Furthermore, in this embodiment, a structure is adopted in which the piston 4 and the projectile 5 in the switching device 10 are integrally joined. This makes it possible to suppress rotation and axial misalignment of the projectile 5 when the projectile 5 moves toward the firing direction D1 during the operation of the switching device 10. In other words, the projectile 5 can be lowered along the axis CL of the cylindrical space 3 while maintaining a stable attitude of the projectile 5. Also, by fixing the projectile 5 to the piston 4, it is possible to suppress the projectile 5 from returning in the opposite direction to the firing direction D1, i.e., toward the first position P1, due to the impact when the wedge portions 521 of each projection 52A, 52B on the projectile 5 are received in the recess 117 of the housing 1. Moreover, the effect of the structure in which the projectile 5 is integrally fixed to the piston 4 as described above becomes even more pronounced when combined with the method in which the projections 52A, 52B of the projectile 5 are inserted into the insertion holes 63 formed in the first conductive pieces 6A, 6B, as in this embodiment.

[0062] Furthermore, when a structure is adopted in which the piston 4 and the projectile 5 are integrally joined, the piston 4 may be arranged in the cylindrical space 3 in a manner that restricts the rotation of the piston 4 around its axial direction. By doing so, the rotation of the projectile 5 launched when the switching device 10 is operated can be suppressed even more effectively. As a structure for restricting the rotation of the piston 4 around its axial direction, one example is to make the outer circumference shape of the piston 4 (sliding part 41) and the inner wall surface shape of the housing 1 side on which the piston 4 (sliding part 41) slides (the inner wall surface of the large diameter portion 122 of the top holder 12) polygonal.

[0063] <Embodiment 2> Next, the switching device 10A according to Embodiment 2 will be described. Here, the differences from Embodiment 1 will be the main focus of the description, and components common to the switching device 10 according to Embodiment 1 will be given the same reference numerals, and detailed explanations will be omitted.

[0064] Figure 7 is a longitudinal cross-sectional view showing the state of the switching device 10A according to Embodiment 2 before operation. Figure 8 is a longitudinal cross-sectional view showing the state of the switching device 10A according to Embodiment 2 after operation. The switching device 10A according to this embodiment differs from the switching device 10 according to Embodiment 1 in that a pair of second conductor pieces 7A, 7B are not provided in the housing 1. Accordingly, it differs from the switching device 10 according to Embodiment 1 in that second retaining holes 115A, 115B are not formed in the housing 1, and the projectile 5 is arranged alone in the cylindrical space 3 instead of the conductor component 8. The switching device 10A configured in this way is used as a device that instantaneously switches a first electrical circuit, which is partially formed by a pair of first conductor pieces 6A, 6B, from an interrupted state to a conductive state. The first electrical circuit may be configured as a short-circuit circuit that short-circuits the current by switching from an interrupted state to a conductive state, for example, in order to discharge the charge accumulated in the circuit or component to be protected. Furthermore, the first electrical circuit may be configured as a circuit to bypass a faulty component in the electrical equipment, such as a semiconductor element or a battery cell, if any of the circuits constituting the electrical equipment fail.

[0065] As shown in Figure 7, the cylindrical space 3 formed within the housing 1 of the switching device 10A houses the piston 4 and the projectile 5. The projectile 5 is composed of a base body 51 and projections 52A and 52B, as described in Embodiment 1, and the base body 51 is positioned at a first position P1 in the initial state before the switching device 10A is activated. Of course, when the base body 51 of the projectile 5 is positioned at the first position P1, the projectile 5 is held away from the pair of first conductive pieces 6A and 6B.

[0066] The projectile 5 may be held in the first position P1 by, for example, temporarily fixing the base body 51 to the inner wall surface of the housing 1 that defines the cylindrical space 3. For example, by press-fitting the base body 51 into the inner wall surface of the housing 1 that defines the cylindrical space 3, the projectile 5 may be prevented from falling downward before the switching device 10A is activated, and when the switching device 10A is activated, the projectile 5 may be launched in the launch direction D1 by the energy of the combustion gas released from the igniter 2.

[0067] In the switching device 10A configured as described above, the relationship between the projectile 5 and the piston 4 is the same as in Embodiment 1. That is, in the initial state before the switching device 10A is activated, the lower surface (tip surface) 42A of the rod portion 42 of the piston 4 is positioned to face the upper surface 51A of the base body 51 of the projectile 5. Also in this embodiment, the projectile 5 and the piston 4 are fixed together. Therefore, when the igniter 2 is activated, the energy of the combustion gas released from the igniter 2 into the cylindrical space 3 causes the piston 4 and the projectile 5 to be launched together in the cylindrical space 3 toward the firing direction D1. As a result, each projection 52A, 52B on the projectile 5 is inserted into the insertion hole 63 of the pair of first conductor pieces 6A, 6B and comes into contact with the edge of the insertion hole 63, thereby quickly switching the first electrical circuit from a disconnected state to a conductive state.

[0068] <Embodiment 3> Next, the switching device 10B according to Embodiment 3 will be described. Here, the differences from Embodiment 2 will be the main focus of the description, and components common to the switching device 10A according to Embodiment 2 will be given the same reference numerals, and detailed explanations will be omitted.

[0069] Figure 9 is a longitudinal cross-sectional view of the switching device 10B according to Embodiment 3 before operation. The switching device 10B differs from the switching device 10A, in that the piston 4 and the projectile 5 are fixed together via a screw 9, while the switching device 10B has the same structure as the switching device 10A in other respects. The screw 9 includes a shaft portion 91 with screw threads formed on its outer circumference and a head portion 92 connected to the end of the shaft portion 91. In this embodiment, the base body 51 of the projectile 5 has a screw hole 51C through which the shaft portion 91 of the screw 9 is inserted. In addition, the lower surface 42A of the rod portion 42 of the piston 4 is provided with a screw hole 43 into which the shaft portion 91 is inserted. The screw hole 43 of the rod portion 42 is formed as a recess opening into the lower surface 42A, and its inner circumference has screw threads that can be screwed with the screw threads of the shaft portion 91. This configuration also provides the same effects as the switching device 10A according to Embodiment 2. Of course, the integrated structure of the piston 4 and projectile 5 via the screw 9 can be applied to the switching device 10 according to Embodiment 1.

[0070] <Embodiment 4> Next, the switching device 10C according to Embodiment 4 will be described. Here, the differences from Embodiment 1 will be the main focus of the description, and components common to the switching device 10 according to Embodiment 1 will be given the same reference numerals, and detailed explanations will be omitted.

[0071] Figure 10 is a perspective view of the switching device 10C according to Embodiment 4. The switching device 10C according to Embodiment 4 is a modified form of the switching device 10 according to Embodiment 1, and differs from the switching device 10 according to Embodiment 1 in that, as shown in Figure 10, the arrangement axis X1 of the pair of first conductor pieces 6A, 6B and the arrangement axis X2 of the pair of second conductor pieces 7A, 7B are orthogonal to each other when assembled in the housing 1. In this embodiment as well, the pair of second conductor pieces 7A, 7B are held in a state where they are inserted into the second holding holes 115A, 115B in the housing 1, but the second holding holes 115A, 115B are formed on the wall surface of the rectangular housing 1 in a direction perpendicular to the wall surface where the first holding holes 114A, 114B that hold the pair of first conductor pieces 6A, 6B are provided (see Figure 10). Note that in Figure 10, the illustration of the first holding hole 114A and the second holding hole 115B is omitted for drawing purposes.

[0072] Figure 11 is a longitudinal cross-sectional view of the switching device 10C according to Embodiment 4 before operation. Specifically, Figure 11 shows a cross-sectional view of the switching device 10C passing through the axis CL of the cylindrical space 3 and the arrangement axis X1 of the pair of first conductor pieces 6A and 6B.

[0073] Figure 12 is a diagram illustrating the conductor component 8A according to Embodiment 4. Figure 12 shows the plan view (top view), the CC cross-section along the long axis, and the DD cross-section along the short axis of the conductor component 8A. In this embodiment, the conductor component 8A is formed as a member in which the second conductor piece 7A, the projectile 5, and the second conductor piece 7B are integrally connected so that they are arranged in a straight line. In the conductor component 8A, components common to the conductor component 8 according to Embodiment 1 are given the same reference numerals, and a detailed explanation is omitted.

[0074] The pair of second conductor pieces 7A and 7B are formed as conductor pieces extending in one direction, similar to Embodiment 1, and their inner ends 71 ​​are integrally connected to the base body 51 of the projectile 5. Furthermore, the pair of second conductor pieces 7A and 7B are components of the switching device 10C, similar to Embodiment 1, and each of them works together to form a part of a predetermined second electrical circuit in the electrical equipment to which the switching device 10C is applied.

[0075] In the conductor component 8A according to Embodiment 4, a pair of protrusions 52A and 52B are provided projecting downward from the lower surface 51B of the base body 51. In this embodiment, the arrangement axis X2 of the pair of second conductor pieces 7A and 7B is set in a direction perpendicular to the arrangement axis X1 of the pair of first conductor pieces 6A and 6B. Therefore, in the conductor component 8A, the arrangement direction of the pair of protrusions 52A and 52B in the projectile 5 is 90° different from the arrangement direction of the pair of protrusions 52A and 52B in the conductor component 8. That is, in the conductor component 8 according to Embodiment 1, the pair of protrusions 52A and 52B were arranged at intervals along its long axis, but in the conductor component 8A according to Embodiment 4, the pair of protrusions 52A and 52B are arranged at intervals along its short axis. In addition, in the conductor component 8A as well, wedge portions 521 are formed on the tip side of the leg portions 522 of the pair of protrusions 52A and 52B.

[0076] In Figure 11, the alignment axis X2 of the pair of second conductor pieces 7A and 7B extends perpendicular to the alignment axis X1 of the pair of first conductor pieces 6A and 6B, i.e., along the depth direction of the drawing. The alignment direction of the pair of protrusions 52A and 52B in the conductor component 8A is set parallel to the alignment axis X1 of the pair of first conductor pieces 6A and 6B.

[0077] In this embodiment as well, in the initial state shown in Figure 11, the tip positions (lower end positions) of each projection 52A, 52B on the projectile 5 are positioned above the pair of first conductor pieces 6A, 6B, and the projectile 5 is separated from the pair of first conductor pieces 6A, 6B (non-contact state). Furthermore, when assembling the conductor component 8 into the housing 1, the projectile 5 is positioned so that the center of the base body 51 of the projectile 5 passes through the axis CL of the cylindrical space 3. In the initial state shown in Figure 11, the axes CL2, CL3 of the projections 52A, 52B are parallel to the axis CL of the cylindrical space 3, and their positional relationship is defined such that the central axes of the insertion holes 63 and recesses 117 of the pair of first conductor pieces 6A, 6B are located on axes CL2, CL3.

[0078] In the switching device 10C according to Embodiment 4 configured as described above, in the initial state shown in Figure 11, the pair of first conductor pieces 6A and 6B are separated from each other, so the first electrical circuit, which is partially formed by this pair of first conductor pieces 6A and 6B, is kept in an interrupted state. On the other hand, in the initial state, the pair of second conductor pieces 7A and 7B are electrically connected via the projectile 5, so the second electrical circuit is in a conductive state. In addition, in the switching device 10C, the lower surface 42A of the rod portion 42 of the piston 4 is bonded to the upper surface 51A of the base body 51 of the projectile 5, thereby integrally fixing the projectile 5 to the piston 4. Of course, the specific method for integrating the piston 4 and the projectile 5 is not particularly limited. For example, as explained in Figure 9, the piston 4 and the projectile 5 may be integrated using screws 9. In this case, similar to the switching device 10B, screw holes should be formed in the base body 51 of the projectile 5 and in the lower surface 42A of the rod portion 42 of the piston 4.

[0079] The operation of the switching device 10C according to Embodiment 4 is the same as that of the switching device 10 according to Embodiment 1. That is, when the igniter 2 is activated, the piston 4 is forcefully pushed down in the firing direction D1 by the energy (pressure) of the combustion gas released from the igniter 2. As a result, the projectile 5 is separated from each of the second conductor pieces 7A and 7B, electrically disconnecting the pair of second conductor pieces 7A and 7B, and the projectile 5 is launched in the firing direction D1 together with the piston 4. The projectile 5 launched in this way is stretched between the pair of first conductor pieces 6A and 6B located below it, and makes contact with each of the pair of first conductor pieces 6A and 6B. That is, after the pair of protrusions 52A and 52B on the projectile 5 are inserted through the insertion holes 63 on the pair of first conductor pieces 6A and 6B, the tip ends of each protrusion 52A and 52B are received in the recess 117 of the housing 1. At that time, the projections 52A and 52B of the projectile 5 come into contact with the edges of the insertion holes 63 in each of the first conductor pieces 6A and 6B, thereby electrically connecting the pair of first conductor pieces 6A and 6B via the projectile 5. In this way, the switching device 10C can be activated to instantly switch the first electrical circuit from a disconnected state to a conductive state, and the second electrical circuit from a conductive state to a disconnected state.

[0080] The embodiments of the electrical circuit switching device relating to this disclosure have been described above, but each embodiment disclosed herein can be combined with any other features disclosed herein.

[0081] Furthermore, the form of the projectile is not particularly limited in the electrical circuit switching device relating to this disclosure. [Explanation of symbols]

[0082] 1: Housing 2:Igniter 3: Cylindrical space 4: Piston 5: Projectile 6A, 6B: A pair of first conductor pieces 7A, 7B: A pair of second conductor pieces 8: Conductor components 10,10A: Electrical circuit switching device

Claims

1. An electrical circuit switching device that switches a predetermined first electrical circuit from an interrupted state to a conductive state when in operation, Housing and An igniter provided in the housing, which releases combustion gas when in operation, A cylindrical space formed within the housing and extending in one direction, The igniter is positioned at a predetermined first position in the cylindrical space in its initial state before operation, and comprises a conductive projectile. In the initial state, the piston is positioned in the cylindrical space between the igniter and the projectile, and is fixed integrally with the projectile in advance. When the igniter is activated, the piston is launched in a predetermined firing direction along the cylindrical space by the energy of the combustion gases. A pair of first conductor pieces are inserted in the cylindrical space at positions on the firing direction side of the first position, separated from each other, and each of the first conductor pieces cooperates to form a part of the first electrical circuit, Equipped with, When the igniter is activated, the projectile, launched together with the piston, contacts each of the pair of first conductive pieces, thereby switching the first electrical circuit from a disconnected state to a conductive state. Electrical circuit switching device.

2. The aforementioned electrical circuit switching device is further capable of switching a predetermined second electrical circuit from a conductive state to a disconnected state when in operation, The cylindrical space is further comprising a pair of second conductor pieces inserted at a distance from each other, each of which cooperates to form a part of a second electrical circuit, In the initial state described above, the pair of second conductor pieces are electrically connected via the projectile, causing the second electrical circuit to be in a conductive state. When the projectile is launched in the launch direction, the electrical connection between the pair of second conductor pieces via the projectile is released, thereby switching the second electrical circuit from a conductive state to a disconnected state. The electrical circuit switching device according to claim 1.

3. In the initial state, the projectile is interposed between the pair of second conductive pieces and they are connected together, and the projectile is separated from each of the pair of second conductive pieces by the energy of the combustion gas. The electrical circuit switching device according to claim 2.

4. An electrical circuit switching device that switches a predetermined first electrical circuit from an interrupted state to an conductive state when in operation, Housing and An igniter provided in the housing, which releases combustion gas when in operation, A cylindrical space formed within the housing and extending in one direction, The igniter is positioned at a predetermined first position in the cylindrical space in its initial state before operation, and comprises a conductive projectile. A piston is fixed to the projectile and positioned in the cylindrical space so as to be interposed between the igniter and the projectile, and is launched in a predetermined firing direction along the cylindrical space by the energy of the combustion gas, A pair of first conductor pieces are inserted in the cylindrical space at positions on the firing direction side of the first position, separated from each other, and each of the first conductor pieces cooperates to form a part of the first electrical circuit, Equipped with, When the igniter is activated, the projectile, launched together with the piston, comes into contact with each of the pair of first conductive pieces, thereby switching the first electrical circuit from an interrupted state to a conductive state. The projectile comprises a base body positioned at the first position in the initial state, and a pair of projections extending from the base body toward the firing direction. Each of the pair of first conductor pieces is provided with an insertion hole into which the projection from the projectile can be inserted, and the first electrical circuit is switched from an interrupted state to a conductive state when the projection comes into contact with the edge of the insertion hole. Electrical circuit switching device.

5. The electrical circuit switching device according to claim 4, wherein a wedge-shaped portion is formed on the tip side of the projection.

6. When the projection is inserted into the insertion hole, the leg portion of the projection that is located closer to the base body than the wedge portion is configured to widen the insertion hole. The electrical circuit switching device according to claim 5.

7. The piston is arranged in the cylindrical space in such a manner that its rotation around the axial direction is restricted. An electrical circuit switching device according to any one of claims 1 to 6.

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