Signal transfer device

Abstract

The present invention is a signal transmission system (10) that can receive a non-electric input signal such as a mechanical shock, detonation, or pyrotechnic signal at an input terminus (12), convert that signal to an electrical signal, and convey the electrical signal to at least one output terminus (16a, 16b) at a remote location where the signal is converted to a non-electric output. To convert the non-electric input signal to an electrical signal, the input terminus (12) comprises a receiving transducer e.g., a piezoelectric, electrochemical, or photovoltaic element. The input terminus (12) is connected by transfer wiring (14) (e.g., an electrical wire harness or a flex cable) to the remote location, where it is received by the at least one output terminus (16a, 16b) and there converted to a non-electric signal that is used for a desired function. The length of the transfer wiring (14), and therefore the distance from the input terminus (12) to the remote location, can be from less than one inch to greater than 100 feet. Optionally, the transfer wiring (14) can connect the input terminus (12) to a plurality of output termini (16a, 16b). Also optionally, an output terminus may comprise an explosive bridge element (SCB, hot bridge-wire, exploding foil) which can be initiated by the electrical signal, and the bridge element may initiate a brisant output charge (explosive or pyrotechnic). Alternatively, the output terminus may comprise an output transducer, e.g., a piezoelectric transducer, to convert the electrical signal into a physical pulse.

Description

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to signal transfer devices and, in particular, to devices for converting non-electrical signals to electrical signals that can be conveyed electrically to a remote location.

[0004] 2. Related Art

[0005] U.S. Pat. No. 5,435,248 to Rode et al, dated Jul. 25, 1995 and entitled “Extended Range Digital Delay Detonator”, discloses an electronic delay detonator for use on the end of a shock tube signal line 10. The detonator contains a lead azide booster charge 20 positioned to receive a non-electric initiation signal from the shock tube 10. The booster charge 20 is positioned in proximity to a piezoelectric generator 30. Upon receipt of a non-electric initiation signal from shock tube 10, the booster charge 20 detonates, causing the piezoelectric generator 30 to produce an electrical pulse that powers the digital delay circuitry and provides energy for the electrical initiation of the output charge in the detonator.

[0006] U.S. Pat. No. 5,377,592 to Rode et al, dated Jan. 3, 1995 and entitled “Impulse Signal Delay Unit”, discloses an in-line signal delay unit attached to the end of the length of shock tube 14. The unit comprises a booster charge and a piezoelectric generator for converting a non-electric initiation signal in the shock tube into an electrical signal. The electrical signal is conveyed via electrical leads, 30a, 30b to the delay module 32. Delay module 32 is connected via output leads, 44a, 44b to an output detonator 48, which contains a bridgewire 45, and an igniter element 46 and an output charge 54. In use, a non-electric initiation signal is transmitted by shock tube 14 and is converted via piezoelectric generator 28 to an electrical pulse that powers the delay module 32. At the end of the programmed delay, an electrical signal is emitted to output leads 44a, 44b to generate an non-electric output signal from output detonator 48. Detonator 48 can then initiate a signal in one or more other lengths of shock tube 16.

SUMMARY OF THE INVENTION

[0007] This invention relates to a communication device for receiving and emitting non-electrical signals, comprising a signal-receiving transducer in an input housing for receiving a non-electrical input signal and converting the non-electric input signal into an electrical signal, a signal conduit comprising an electrical conductor having an input end and at least one output end, with the input end of the electrical conductor connected to the signal-receiving transducer to receive and conduct the electrical signal, and an output initiation element in an output housing on at least one output end of the electrical conductor for emitting a non-electric output signal from the electrical signal.

[0008] According to one aspect of the invention, the signal-receiving transducer may comprise a piezoelectric element configured to generate an electrical signal in response to a percussive input signal. Optionally, there may be an input charge in the input housing in signal transfer relation to the signal-receiving transducer.

[0009] According to various other aspects of the invention, the electrical conductor may comprise a plurality of output ends and an output initiation element in an output housing on each output end; and the signal conduit may optionally comprise a metal shield within which the conductor is disposed.

[0010] Optionally, at least one output initiation element may comprise one of a solid state bridge element and a piezoelectric element. For example, an output initiation element may comprise a voltage-protected SCB. Alternatively, an output initiation element may comprise one of a bridgewire and an exploding foil.

[0011] In a particular embodiment, the output housing may contain an output charge of reactive material in signal transfer relation to the output initiation element.

[0012] This invention also relates to a method for initiating at least one non-electric effector in response to a non-electric input signal. The method comprises delivering a non-electric input signal to a signal-receiving transducer in an input housing whereby to convert the non-electrical input signal into an electrical signal, conveying the electrical signal along a conduit from the first housing to at least one output initiation element in an output housing, and emitting an initiation signal from the output initiation element in the output housing to initiate the effector.

[0013] According to one aspect of the invention, the non-electric input signal may comprise a percussive signal and the signal-receiving transducer may comprise a piezoelectric element. Optionally, delivering the non-electric input signal comprises striking the piezoelectric element with a firing pin. Alternately, delivering the non-electric input signal may comprise initiating a charge of reactive material that is disposed in signal transfer relation to the piezoelectric element.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a schematic view of a signal transfer device according to one embodiment of this invention;

[0015] FIG. 2 is a schematic view of a signal transfer device according to a second embodiment of this invention;

[0016] FIG. 3 is a schematic cross-sectional view of an assault weapon that utilizes a signal transfer device according to one embodiment of this invention; and

[0017] FIG. 4 is a close-up schematic view of the input terminus of the signal transfer device in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS THEREOF

[0018] Prior art transmission devices for non-electric signals employ non-electric signal transmission lines to carry a non-electric signal from one terminus to another that may be connected to a device that requires a non-electric initiation signal for its operation (an “effector”). Common non-electric signal transmission lines include shock tube, thin line explosive (TLX), flexible confined detonating cord (FCDC), and detonating cord. These types of lines can carry and emit only one signal. To direct the one non-electric signal to multiple outputs for multiple effectors, especially in launch vehicles, it is known in the art to employ a manifold. However, adding a manifold adds weight and cost to the system, and decreases the predicted reliability, since additional components are added. Shock tube and TLX systems have temperature constraints associated with them that may not be an issue with a wired system.

[0019] This invention provides cost savings in the replacement of non-electric signal transfer lines with wire, cost savings in the elimination of manifolds and the connectors associated with them, increased reliability (since many of the components can be tested in the manufacturing process), and system utility in environments where non-electric explosive components could not be used.

[0020] The present invention is a signal transmission system that can receive a non-electric input signal such as a mechanical shock, detonation, or pyrotechnic signal at an input terminus, convert that signal to an electrical signal, and convey the electrical signal to at least one output terminus at a remote location where the signal is converted to a non-electric output.

[0021] To convert the non-electric input signal to an electrical signal, the input terminus comprises a signal-receiving transducer e.g., a piezoelectric, electrochemical, or photovoltaic element in an input housing. The input terminus is connected by a signal conduit that comprises an electrical conductor (e.g., an electrical wire harness or a flex cable) having at least one output end at a remote location (i.e., outside the input housing), where the signal is received and there converted to a non-electric signal that is used for a desired function of an output initiation element. The length of the conductor, and therefore the distance from the input terminus to the remote location, can be from less than one inch to greater than 100 feet. Optionally, the signal conduit can connect the input terminus to a plurality of output termini, i.e., the electrical conductor may branch off from the input terminus to a plurality of output termini.

[0022] An output terminus may comprise an output housing for an initiation element such as a bridgewire, exploding foil, or a solid state bridge element (e.g., SCB) which can be initiated by the electrical signal. There may be a brisant output charge (explosive or pyrotechnic) in the output housing that is initiated by the initiation element. Alternatively, the output terminus may comprise an output transducer, e.g., a piezoelectric transducer, to convert the electrical signal into a physical pulse.

[0023] Although this invention could be used in a launch vehicle, tactical missile, or weapon system for effectors such as exploding bolts, separation fairings, motor initiators, etc., it could also be used for automotive airbag or pretensioner initiation, aircraft or railroad safety systems, or in mining, blasting, demolition, or seismic exploration applications.

[0024] In a first illustrative embodiment of this invention depicted schematically in FIG. 1, the system 10 comprises a non-electric input terminus 12 which is connected by a signal conduit that comprises an electrical conductor, i.e., transfer wiring 14 (which may comprise a flex circuit) to output termini 16a and 16b. Input terminus 12 comprises a metal casing or housing 18 within which a detonation or pyrotechnic input charge 20 is closely coupled to an optional buffering element 22. The purpose of such a buffering element, which is well-known in the art, is to attenuate or shape the shock wave that is generated from the input charge for a better conversion by the signal-receiving transducer 24. The housing 18 contains transducer 24 (e.g., a piezoelectric element) which receives the buffered shock input from input charge 20 and converts its mechanical energy into an electrical charge. The electrical charge generates a voltage potential that causes current to flow through the transfer wiring which branches to connect to the output termini 16a, 16b. The output termini 16a, 16b, may comprise electrical output initiation elements 26a, 26b, such as a bridgewire, exploding foil, semiconductor bridge (SCB) or other solid state bridge element, etc., encased in metal shells or output housings 28a, 28b. Low energy SCBs typically function with less than 3 milliJoules of energy. The output initiation element converts the electrical signal to a non-electrical signal (physical impulse, detonation, deflagration, plasma, heat, etc.) that can initiate an associated effector.

[0025] Optionally, the output initiation element may comprise a voltage-protected SCB, which has an anti-fuse layer built into the device that acts as a switch. There must be a voltage of greater than 140V (between 150V and 250V) across the leads, i.e., across the bridge, to turn the switch on, i.e., to allow current flow through the bridge.

[0026] Output housings 28a, 28b also contain optional output charges 30a, 30b that are sensitive to initiation by the output initiation elements 26a, 26b. The output termini could thus perform a number of different functions, such as motor ignition or stage separation on a launch vehicle or tactical missile, skin severance on a weapon system, initiation for an automotive airbag or pretensioner event, munitions dispensing for an aircraft application, or signal transfer in any other type of system that requires explosive initiation.

[0027] In the signal conduit, the transfer wiring 14 is optionally encased in a metallic shield 32. The effect of the metal housings 18, 28a, 28b and metal shield 32 together create a Faraday cage around the signal-receiving transducer, the transfer wiring and the output transducer, thus mitigating interference from external electrical fields, stray voltage, or electrostatic discharge (ESD).

[0028] The input terminus 12 may be equipped for securing a signal-transmitting device, e.g., a squib, detonator or a length of non-electric signal transmission line (e.g., detonating cord), in signal transfer relation to the input charge or, if there is no input charge, in impulse transfer relation to the transducer. For example, the input terminus may be fitted with a connector block of the kind shown in, e.g., U.S. Pat. No. 5,398,611 to Michna et al, dated Mar. 21, 1995, or U.S. Pat. No. 5,703,320 to Lucca et al, dated Dec. 30, 1997 (both of which are hereby incorporated herein by reference) to secure a detonating cord in signal transfer relation to input charge 20.

[0029] In a modification of system 10, the input charge 20 and buffering element 22 can be eliminated if sufficient mechanical/shock energy is transferred directly to the transducer 24 from an external source, such as a spring-driven firing pin or a detonation charge, to generate the desired output signal from the transducer.

[0030] In an alternate configuration shown in FIG. 2, the system 10′ comprises an input terminus 12 and transfer wiring 14 like those of FIG. 1. However, the output termini 34a, 34b, instead of comprising bridge elements, contain piezoelectric elements 32a, 32b as the output transducers. The high current energy from the input terminus 12 is received by piezoelectric elements 32a, 32b, via transfer wiring 14, and causes them to produce mechanical responses, e.g., physical pulses. The piezoelectric elements 32a, 32b can be pressed against a charge of explosive material so that the movement of the piezoelectric element initiates the explosive material. One or more output termini could also be used to affect the surface of another device, e.g., the piezoelectric elements 32a, 32b could be placed against the skin of an airplane to assist in de-icing the plane by imposing momentary deflections on the skin material.

[0031] Signal transfer devices according to this invention find utility in the field of ignition systems for shoulder mount assault weapons. One embodiment of such a system is depicted in FIGS. 3 and 4. As seen in FIG. 3, weapon 40 comprises a barrel or tube 42 within which is disposed a projectile 44. The projectile 44 may be, e.g., an armor-piercing shell that may comprise a warhead 46 and a rocket motor 48. The warhead 46 contains a fusing apparatus 50, which may include a piston actuator or other initiating device known in the art. The firing system for weapon 40 includes a signal transfer device in accordance with this invention. The device comprise an input terminus 52, an output terminus 54 situated within the rocket motor 48 so that it can ignite the motor, and transfer wiring 56 connected between the input terminus 52 and the output terminus 54, for conveying electrical signal from one terminus to the other. The warhead 46 contains an electrically triggered fusing apparatus 50 that is connected to transfer wiring 56 and that constitutes a second output terminus.

[0032] Input terminus 52 is positioned adjacent to a spring-driven firing pin mechanism 58 which comprises part of a conventional triggering mechanism.

[0033] As is better seen in FIG. 4, input terminus 52 comprises a mounting sleeve or housing 66 that contains a percussion-sensitive primer 60 held in housing 66 by a primer seat 60a, a small booster charge 62 that may comprise lead azide and a piezoelectric signal-receiving transducer 64. Primer seat 60a provides a short off-set shoulder or touch hole 68 between the primer 60 and the booster charge 62, which imposes a distance between them but nevertheless positions the primer so that it can initiate the booster charge. The booster charge 62 is configured and positioned so that, upon initiation, it can cause the piezoelectric transducer 64 to generate an adequate pulse of electricity into transfer wiring 56. Input terminus 52 is mounted in a positioning bracket or body 70 which holds input terminus 52 in position to receive the non-electric input from the firing pin mechanism 58.

[0034] To operate weapon 40, the user aims the weapon and employs the triggering mechanism to cause firing mechanism 58 (FIG. 3) to drive firing pin 58a to strike the percussion-sensitive primer 60 of input terminus 52. The primer 60 initiates the booster charge 62, which generates a detonation output that causes the piezoelectric transducer 64 to generate an electrical pulse that is delivered to wiring 56. The electrical pulse is conveyed via wiring 56 to the output terminus 54, which comprises a conventional electrical initiating squib which contains a bridge element and a charge of reactive (explosive or pyrotechnical) material. The bridge element converts the electrical signal to heat or other non-electric output sufficient to initiate the reactive material in the squib so that the squib can generate its brisant output. The squib, in turn, initiates the rocket motor 48. Part of the electrical pulse from the piezoelectric transducer 64 is branched off to another output terminus which is coupled to fusing apparatus 50 and which has an output initiation element suited to initiate the fusing apparatus 50 of the warhead in conjunction with the firing of the rocket projectile.

[0035] While the invention has been described with reference to a specific embodiment thereof, it will be understood upon a reading and understanding of the forgoing disclosure that numerous variations and alterations of the described embodiment fall within the scope and spirit of the invention and within the scope of the appended claims.

Claims

1. A communication device for receiving and emitting non-electrical signals, comprising: a signal-receiving transducer in an input housing for receiving a non-electrical input signal and converting the non-electric input signal into an electrical signal; a signal conduit comprising an electrical conductor having an input end and at least one output end, with the input end of the electrical conductor connected to the signal-receiving transducer to receive and conduct the electrical signal; and an output initiation element in an output housing on at least one output end of the electrical conductor for emitting a non-electric output signal from the electrical signal.

2. The device of claim 1 wherein the signal-receiving transducer comprises a piezoelectric element configured to generate an electrical signal in response to a percussive input signal.

3. The device of claim 2 comprising an input charge in the input housing in signal transfer relation to the signal-receiving transducer.

4. The device of claim 1 wherein the electrical conductor comprises a plurality of output ends and comprising an output initiation element in an output housing on each output end.

5. The device of claim 1 wherein the signal conduit comprises a metal shield within which the conductor is disposed.

6. The device of claim 1 wherein at least one output initiation element comprises one of a solid state bridge element and a piezoelectric element.

7. The device of claim 6 wherein at least one output initiation element comprises a voltage-protected SCB.

8. The device of claim 1 wherein at least one output initiation element comprises one of a bridgewire and an exploding foil.

9. The device of claim 1 wherein the output housing contains an output charge of reactive material in signal transfer relation to the output initiation element.

10. A method for initiating at least one non-electric effector in response to a non-electric input signal, the method comprising: delivering a non-electric input signal to a signal-receiving transducer in an input housing whereby to convert the non-electrical input signal into an electrical signal; conveying the electrical signal along a conduit from the first housing to at least one output initiation element in an output housing; and emitting an initiation signal from the output initiation element in the output housing to initiate the effector.

11. The method of claim 10 wherein the non-electric input signal comprises a percussive signal and the signal-receiving transducer comprises a piezoelectric element.

12. The method of claim 11 wherein delivering the non-electric input signal comprises striking the piezoelectric element with a firing pin.

13. The method of claim 11 wherein delivering the non-electric input signal comprises initiating a charge of reactive material that is disposed in signal transfer relation to the piezoelectric element.

14. The device of claim 10 wherein at least one output initiation element comprises one of a solid state bridge element and a piezoelectric element.

15. The device of claim 14 wherein the output initiation element comprises a voltage-protected SCB.

16. The device of claim 10 wherein at least one output initiation element comprises a bridgewire.