System and method for safing and arming a bore-launched projectile

Abstract

A safing and arming (SA) system and method for a bore-launched projectile is provided. The SA system includes an arming switch, including a detonator, movable from a first position to a second position. When the arming switch is in the first position, the detonator is separated from an explosive train of the projectile. When the arming switch is in the second position, the detonator is substantially aligned with the explosive train, allowing the projectile to be armed. Safing systems are provided for retaining the arming switch in the first (safe) position. Various embodiments also allow for release of the arming switch so as to allow the arming switch to be moved to the second (armed) position, wherein the release may be triggered by a selected acceleration force exerted on the projectile and/or a determination that the projectile has been launched from the launch bore.

1 . A safing and arming system adapted to be operably engaged with a projectile including an explosive train, the projectile being adapted to be launched from a launch bore, the system comprising:
 an arming switch configured to be movable from a first position to a second position, the arming switch being further configured to operably engage a detonator such that, when the arming switch is in the first position, the detonator operably engaged therewith is substantially out of alignment with the explosive train and such that, when the arming switch is in the second position, the detonator operably engaged therewith is substantially aligned with the explosive train such that the explosive train is capable of being armed;   a first acceleration safety device configured to be capable of operably engaging the arming switch so as to normally retain the arming switch in the first position, the first acceleration safety device being further configured to disengage the arming switch so as to allow the arming switch to be moved to the second position, in response to an acceleration force having a selected magnitude and a selected duration, the acceleration force being imparted on the first acceleration safety device by an acceleration of the projectile with respect to the launch bore during a launch of the projectile; and   a proximity safety device configured to be capable of operably engaging the arming switch so as to normally retain the arming switch in the first position, the proximity safety device being further configured to sense an inner wall defining the launch bore so as to allow the arming switch to be moved to the second position, such that the explosive train is capable of being armed, when the projectile is launched from the launch bore.   
   
   
       2 . A safing and arming system according to  claim 1 , wherein the proximity safety device comprises:
 a first pin slidably disposed in a first pin, the first pin including a first end configured to contact the inner wall of the launch bore and a second end configured to engage the arming switch so as to normally retain the arming switch in the first position when the projectile is disposed within the launch bore; and   a biasing element operably engaged with the first pin, and configured to bias the first pin towards the inner wall of the launch bore such that, when the projectile is launched from the launch bore, the first end of the first pin becomes unconstrained, and the second end of the first pin disengages the arming switch such that the arming switch is capable of being moved to the second position so that the explosive train is capable of being armed.   
   
   
       3 . A safing and arming system according to  claim 1 , further comprising an actuator device operably engaged with the arming switch and configured to be capable of moving the arming switch from the first position to the second position in response to a signal. 
   
   
       4 . A safing and arming system according to  claim 3 , wherein the proximity safety device further comprises a tab configured to normally cover an optical sensor in communication with the detonator, the tab being configured to uncover the optical sensor when the projectile is launched from the launch bore such that the optical sensor is capable of transmitting the signal to the actuator device so that the actuator device is capable of moving the arming switch from the first position to the second position at a selected time after the projectile is launched from the launch bore. 
   
   
       5 . A safing and arming system according to  claim 3 , further comprising:
 a wiring assembly configured to short circuit the signal to prevent the signal from being transmitted to the actuator device; and   a second acceleration safety device configured to be capable of disabling the wiring assembly in response to the acceleration force such that the signal is capable of being transmitted to the actuator device.   
   
   
       6 . A safing and arming system according to  claim 1 , wherein the arming switch comprises a rotatable cylinder having a central axis and defining an arming channel extending radially outward from the central axis, the arming channel being configured to receive the detonator such that, as the rotatable cylinder is rotated from the first position to the second position, the detonator becomes substantially aligned with the explosive train so that the explosive train is capable of being armed. 
   
   
       7 . A safing and arming system according to  claim 1 , wherein the first acceleration safety device comprises:
 a first setback weight slidably disposed in a first setback weight chamber;   a second pin configured to be capable of operably engaging the arming switch so as to normally retain the arming switch in the first position; and   a first linkage arm operably engaged between the first setback weight and the second pin such that, as the first setback weight slides within the first setback weight chamber in response to the acceleration force, the first linkage arm is configured to disengage the second pin from the arming switch so as to allow the arming switch to be moved to the second position.   
   
   
       8 . A safing and arming device according to  claim 7 , wherein the first setback weight is configured to slide within the first setback weight chamber in response to the acceleration force having the selected magnitude and the selected duration. 
   
   
       9 . A safing and arming system according to  claim 5 , wherein the second acceleration safety device comprises:
 a second setback weight slidably disposed in a second setback weight chamber;   a cutting device slidably disposed in a cutting channel; and   a second linkage arm operably engaged between the second setback weight and the cutting device such that, as the second setback weight slides within the second setback weight chamber in response to the acceleration force, the second linkage arm is configured to move the cutting device within the cutting channel such that the cutting device cuts at least one wire within the wiring assembly so that the signal is capable of being transmitted to the actuator device.   
   
   
       10 . A safing and arming device according to  claim 9 , wherein the second setback weight is configured to slide within the second setback weight chamber in response to the acceleration force having the selected magnitude and the selected duration. 
   
   
       11 . A safing and arming system according to  claim 5 , wherein the wiring assembly comprises electrical connections selected from the group consisting of:
 a short circuit connection to ground for the signal;   a short circuit connection to ground for a detonator arming signal;   a short circuit connection to ground for an electronic controller configured to control the detonator; and   combinations thereof.   
   
   
       12 . A safing and arming system adapted to be operably engaged with a projectile including an explosive train, the projectile being adapted to be launched from a launch bore, the system comprising:
 an arming switch configured to be movable from a first position to a second position, the arming switch being further configured to operably engage a detonator such that, when the arming switch is in the first position, the detonator operably engaged therewith is substantially out of alignment with the explosive train and such that, when the arming switch is in the second position, the detonator operably engaged therewith is substantially aligned with the explosive train such that the explosive train is capable of being armed;   an actuator device operably engaged with the arming switch and configured to move the arming switch from the first position to the second position in response to a signal; and   a proximity safety device configured to be capable of operably engaging the arming switch so as to normally retain the arming switch in the first position, the proximity safety device being further configured to sense an inner wall defining the launch bore so as to allow the arming switch to be moved to the second position when the projectile is launched from the launch bore, such that the arming switch is capable of being moved to the second position so that the explosive train is capable of being armed, the proximity safety device further comprising a tab configured to normally cover an optical sensor in communication with the detonator, the tab being configured to uncover the optical sensor when the projectile is launched from the launch bore such that the optical sensor is capable of transmitting the signal to the actuator device so that the actuator device is capable of moving the arming switch from the first position to the second position at a selected time after the projectile is launched from the launch bore.   
   
   
       13 . A safing and arming system according to  claim 12 , wherein the proximity safety device further comprises:
 a first pin slidably disposed in a first pin channel, the first pin including a first end configured to contact the inner wall of the launch bore, the first pin also including a second end configured to engage the arming switch so as to normally retain the arming switch in the first position, the tab being configured to extend from the first pin so as to normally cover the optical sensor in communication with the detonator when the projectile is disposed within the launch bore; and   a biasing element operably engaged with the first pin, and configured to bias the first pin towards the inner wall of the launch bore such that, when the projectile is launched from the launch bore, the first end of the first pin becomes unconstrained, and the second end of the first pin disengages the arming switch so that the actuator device is capable of moving the arming switch to the second position, such that the explosive train in capable of being armed and such that the tab uncovers the optical sensor so that the optical sensor is capable of transmitting the signal to the actuator device to move the arming switch from the first position to the second position at a selected time after the projectile is launched from the launch bore.   
   
   
       14 . A safing and arming system according to  claim 12 , further comprising a first acceleration safety device configured to be capable of operably engaging the arming switch so as to normally retain the arming switch in the first position, the first acceleration safety device being further configured to disengage the arming switch in response to an acceleration force having a selected magnitude and a selected duration, the acceleration force being imparted on the first acceleration safety device by an acceleration of the projectile with respect to the launch bore during a launch of the projectile. 
   
   
       15 . A safing and arming system according to  claim 12 , further comprising:
 a wiring assembly configured to short circuit the signal to prevent the signal from being transmitted to the actuator device; and   a second acceleration safety device configured to be capable of disabling the wiring assembly in response to a force having a selected magnitude and a selected duration, imparted on the second acceleration safety device by an acceleration of the projectile with respect to the launch bore during a launch of the projectile such that the signal is capable of being transmitted to the actuator device.   
   
   
       16 . A safing and arming system according to  claim 12 , wherein the arming switch comprises a rotatable cylinder having a central axis and defining an arming channel extending radially outward from the central axis, the arming channel being configured to receive the detonator such that, as the rotatable cylinder is rotated from the first position to the second position, the detonator becomes substantially aligned with the explosive train so that the explosive train is capable of being armed. 
   
   
       17 . A safing and arming system according to  claim 14 , wherein the first acceleration safety device comprises:
 a first setback weight slidably disposed in a first setback weight chamber;   a second pin configured to be capable of operably engaging the arming switch so as to normally retain the arming switch in the first position; and   a first linkage arm operably engaged between the first setback weight and the second pin such that, as the first setback weight slides within the first setback weight chamber in response to the acceleration force, the first linkage arm is configured to disengage the second pin from the arming switch so as to allow the arming switch to be moved to the second position.   
   
   
       18 . A safing and arming device according to  claim 17 , wherein the first setback weight is configured to slide within the first setback weight chamber in response to the acceleration force having the selected magnitude and the selected duration. 
   
   
       19 . A safing and arming system according to  claim 15 , wherein the second acceleration safety device comprises:
 a second setback weight slidably disposed in a second setback weight chamber;   a cutting device slidably disposed in a cutting channel; and   a second linkage arm operably engaged between the second setback weight and the cutting device such that, as the second setback weight slides within the second setback weight chamber in response to the acceleration force, the second linkage arm is configured to move the cutting device within the cutting channel such that the cutting device cuts at least one wire within the wiring assembly so that the signal is capable of being transmitted to the actuator device.   
   
   
       20 . A safing and arming device according to  claim 19 , wherein the second setback weight is configured to slide within the second setback weight chamber in response to the acceleration force having the selected magnitude and the selected duration. 
   
   
       21 . A safing and arming system according to  claim 15 , wherein the wiring assembly comprises electrical connections selected from the group consisting of:
 a short circuit connection to ground for the signal;   a short circuit connection to ground for a detonator arming signal;   a short circuit connection to ground for an electronic controller configured to control the detonator; and   combinations thereof.   
   
   
       22 . A method for safing and arming a projectile including an explosive train, using a safing and arming system, the projectile being adapted to be launched from a launch bore, the method comprising:
 securing an arming switch in a first position so as to normally retain the arming switch in the first position, the arming switch being configured to be movable from the first position to a second position, and to operably engage a detonator such that, when the arming switch is in the first position, the detonator operably engaged therewith is substantially out of alignment with the explosive train and such that, when the arming switch is in the second position, the detonator operably engaged therewith is substantially aligned with the explosive train such that the explosive train is capable of being armed;   releasing the arming switch so as to allow the arming switch to be moved to the second position, the arming switch being released in response to:
 an acceleration force having a selected magnitude and a selected duration, the acceleration force being imparted on the projectile by an acceleration of the projectile with respect to the launch bore during a launch of the projectile; and 
 a determination that the projectile has been launched from the launch bore. 
   
   
   
       23 . A method according to  claim 22 , wherein the securing step further comprises:
 securing the arming switch in the first position with a first acceleration safety device configured to be capable of operably engaging the arming switch so as to normally retain the arming switch in the first position; and   securing the arming switch in the first position with a proximity safety device configured to be capable of operably engaging the arming switch so as to normally retain the arming switch in the first position, the proximity safety device being further configured to sense an inner wall defining the launch bore.   
   
   
       24 . A method according to  claim 22 , wherein the releasing step further comprises:
 disengaging a first acceleration safety device from the arming switch so as to allow the arming switch to be moved to the second position, in response to an acceleration force having a selected magnitude and a selected duration, the acceleration force being imparted on the first acceleration safety device by an acceleration of the projectile with respect to the launch bore during a launch of the projectile;   sensing the inner wall of the launch bore with a proximity safety device;   determining when the inner wall is no longer sensed by the proximity safety device, after disengaging the first acceleration safety device from the arming switch; and   disengaging the proximity safety device from the arming switch after the determining step so as to allow the arming switch to be moved to the second position such that the explosive train is capable of being armed when the projectile is launched from the launch bore.   
   
   
       25 . A method according to  claim 24 , wherein the proximity safety device comprises a first pin slidably disposed in a first pin channel, and the method further comprises:
 contacting an inner wall of the launch bore with a first end of the first pin when the projectile is disposed within the bore;   engaging a second end of the first pin with the arming switch so as to normally retain the arming switch in the first position when the projectile is disposed within the bore; and   biasing the first pin towards the inner wall of the launch bore, with a biasing element operably engaged therewith, such that, when the projectile is launched from the launch bore, the first end of the first pin becomes unconstrained, and the second end of the first pin disengages the arming switch such that the arming switch is capable of being moved to the second position so that the explosive train is capable of being armed.   
   
   
       26 . A method according to  claim 24 , further comprising moving the arming switch from the first position to the second position, with an actuator device operably engaged therewith, in response to a signal received by the actuator device. 
   
   
       27 . A method according to  claim 26 , wherein the proximity safety device comprises a tab configured to normally cover an optical sensor in communication with the detonator and the actuator device, and the method further comprises:
 moving the tab so as to uncover the optical sensor when the projectile is launched from the launch bore such that the optical sensor is capable of transmitting the signal to the actuator device; and   transmitting the signal from the optical sensor to the actuator device such that the actuator device is capable of moving the arming switch from the first position to the second position at a selected time after the projectile is launched from the launch bore.   
   
   
       28 . A method according to  claim 26 , further comprising:
 Normally short-circuiting the signal with a wiring assembly to prevent the signal from being transmitted to the actuator device;   disabling the wiring assembly in response to the acceleration force with a second acceleration safety device such that the signal is capable of being transmitted to the actuator device; and   transmitting the signal to the actuator device such that the actuator device is capable of moving the arming switch from the first position to the second position.   
   
   
       29 . A method for safing and arming a projectile including an explosive train, using a safing and arming system, the projectile being adapted to be launched from a launch bore, the method comprising:
 securing an arming switch in a first position so as to normally retain the arming switch in the first position, the arming switch being configured to be movable from the first position to a second position, and to operably engage a detonator such that, when the arming switch is in the first position, the detonator operably engaged therewith is substantially out of alignment with the explosive train and such that, when the arming switch is in the second position, the detonator operably engaged therewith is substantially aligned with the explosive train such that the explosive train is capable of being armed;   determining when the projectile has exited the launch bore;   releasing the arming switch so as to allow the arming switch to be moved to the second position after a selected time period following the determining step;   uncovering an optical sensor configured to transmit a signal;   transmitting the signal to an actuator device operably engaged with the arming switch; and   moving the arming switch from the first position to the second position with the actuator device, in response to the transmitted signal, at a selected time after the transmitting step.   
   
   
       30 . A method according to  claim 29 , wherein the securing step further comprises securing the arming switch in the first position with a proximity safety device configured to be capable of operably engaging the arming switch so as to normally retain the arming switch in the first position, the proximity safety device further comprising a tab configured to normally cover an optical sensor in communication with the detonator, the proximity safety device being further configured to sense an inner wall of the launch bore. 
   
   
       31 . A method according to  claim 30 , further comprising:
 determining when the inner wall of the launch bore is no longer sensed by the proximity safety device;   disengaging the proximity safety device from the arming switch after the determining step so as to allow the arming switch to be moved to the second position such that the explosive train is capable of being armed when the projectile is launched from the launch bore; and   moving the tab so as to uncover the optical sensor such that the optical sensor is capable of transmitting the signal.   
   
   
       32 . A method according to  claim 30 , further comprising:
 contacting the inner wall of the launch bore with a first end of a first pin when the projectile is disposed within the launch bore, the first pin being slidably disposed in a first pin channel defined by the system and having the tab operably engaged therewith;   engaging a second end of the first pin with the arming switch so as to normally retain the arming switch in the first position when the projectile is disposed within the launch bore; and   biasing the first pin towards the inner wall of the launch bore, with a biasing element operably engaged with the first pin such that, when the projectile is launched from the launch bore, the first end of the first pin becomes unconstrained, and the second end of the first pin disengages the arming switch such that the arming switch is capable of being moved to the second position so that the explosive train is capable of being armed.   
   
   
       33 . A method according to  claim 29 , further comprising:
 securing the arming switch in the first position with a first acceleration safety device; and   disengaging the first acceleration safety device from the arming switch so as to allow the arming switch to be moved to the second position, in response to an acceleration force having a selected magnitude and a selected duration, the acceleration force being imparted on the first acceleration safety device by an acceleration of the projectile with respect to the launch bore during a launch of the projectile.   
   
   
       34 . A method according to  claim 29 , further comprising:
 Normally short-circuiting the signal with a wiring assembly to prevent the signal from being transmitted to the actuator device;   disabling the wiring assembly in response to the acceleration force with a second acceleration safety device such that the signal is capable of being transmitted to the actuator device; and   transmitting the signal to the actuator device such that the actuator device is capable of moving the arming switch from the first position to the second position.   
   
   
       35 . A method according to  claim 34 , wherein the disabling step comprises cutting at least one wire within the wiring assembly such that the signal is capable of being transmitted to the actuator device.