The present invention relates to the control and actuation of a firing sequence of a firearm. In particular, the present invention relates to a sensor system for monitoring and sensing application of a jarring event or acceleration and/or the movement of a firearm into an undesired orientation, and blocking the firing sequence of the firearm to prevent an inadvertent discharge of the firearm.
Inadvertent discharge of firearms is one of the leading causes of accidental injuries and deaths involving firearms. When a firearm is dropped or experiences the application of a force or other jarring event, the application of such force to the firearm can cause the firearm to inadvertently discharge either by causing the release of the firing pin in a percussion firing system in which the firing pin strikes and thus initiates firing of a round of ammunition within the chamber of a firearm, or, in the case of an electrically actuated firearm, causes an inadvertent trigger signal to be sent to the firearm control system in response to which an electric firing pulse is transmitted to the round of ammunition. In addition, there are times when a firearm is placed in an unsafe orientation or position and its trigger is inadvertently engaged, resulting in an inadvertent or undesired discharge of the firearm. For example, if the firearm is rotated upside down or canted at an angle of more than 45 degrees, such conditions generally are considered unsafe for the discharge of the firearm.
It is important, therefore, to be able to detect when a firearm is subjected to a jarring event and/or undesired movement, such as undue acceleration or being moved into an undesirable or unsafe orientation, and prevent the inadvertent or undesired discharge of the firearm, but without unduly interfering with the normal operation of the firearm and preventing its safe, authorized use.
Briefly described, the present invention relates to a sensor system for sensing firearm orientation and/or jarring events and preventing the firearm from being fired in an unsafe condition. The system includes one or more sensor arrays, having one or more sensors for sensing jarring events or acceleration and/or for determining the orientation of the firearm, mounted to a firearm at desired locations along or within the frame or stock of the firearm, and a control system to process the sensor signals and interrupt a firing sequence of the firearm when appropriate. The system detects acceleration from drops or other jarring events that can be distinguished from normal, safe handling of the firearm, which generally will only introduce a limited amount of acceleration that is significantly below the acceleration typically associated with accidental discharge from jar events. In addition, or alternatively, the system can have the capability of monitoring or sensing changes in firearm orientation(s) to orientations of a firearm that are undesirable or unsafe and that typically would not be used, such as, for example, the firearm being turned upside-down and when the angle or cant of the firearm with respect to one or more predetermined axes or orientation of the firearm passes some threshold value.
In one embodiment, the firing of a firearm will be prevented if excessive jarring or acceleration and/or improper orientation of the firearm are sensed. For purposes of this specification, the term “acceleration” should be construed as to include de-acceleration or negative acceleration as well as positive acceleration. In this embodiment, the firearm sensor system generally is omni-directional, so as to be capable of sensing a jarring event, or other application of force, in any direction, although it may be advantageous to have the sensor system have greater sensitivity in certain directions than others. The firearm sensor system will include one or more inertia switches or acceleration switches configured in a sensor array mounted on a mounting block attached to the firearm to create an omni-directional jar or acceleration sensor. The switches used generally are uni-directional so as to be affected by inertia in only one direction.
Typically, at least four to six unidirectional inertia or acceleration switches are mounted in the array in order to obtain an omni-directional sensor system. It will also be understood that in other systems or applications, as few as a single sensor can be used. Other force or acceleration sensors also can be used, including an accelerometer or system of accelerometers, piezoelectric shock sensors, electrolytic tilt sensors and other acceleration sensors. In addition, it would also be possible to provide a mass suspended from a cantilevered beam that is gauged such as with a strain gauge and use the strain gauge to sense a jarring event. In short, any sensor that can be made to sense acceleration is a possible sensor for stopping the firing sequence of the firearm in event of a jarring or unauthorized force application or unnecessary rapid acceleration. As the firearm is subjected to a jarring event or accelerated above a certain sensor limit or threshold, a sensor signal is generated to indicate a fault condition, in response to which the control system will block the firing sequence and prohibit the firearm from firing.
The sensor system further generally will be capable of measuring or sensing the orientation of the firearm along two or more axes of angle measurement relative to the earth. The first axis of measurement generally is inclination or elevation. The second axis of angle measurement generally measures rotation of the firearm about its bore. The sensor system for obtaining these orientation measurements generally includes an orientation sensor, such as a three-axis magnetometer. However, any sensor or array of sensors that can determine the gun's orientation with respect to a reference or threshold is capable of being used, including, for example, tilt or tip-over switches, inclinometers, accelerometers, and gyros or other types of sensors that can be used to sense or monitor firearm orientation can be used in the present invention. The sensors monitor and generate sensor signal(s) indicating the orientation of the firearm with respect to the predetermined axes, which sensor signal is communicated to the control system. The control system will process the sensor signal(s) to determine if the firearm is in an acceptable firing orientation. If the orientation is determined to be improper or unacceptable, the control system will issue an interrupt signal that will stop the firing sequence if the trigger is pulled.
Though in a preferred embodiment a firearm is kept from firing if it has experienced a jar situation and/or is in an improper orientation, the system does not need to do both. It is possible that a system of sensors could be used to sense only acceleration or a jar event, or the movement of the firearm to an undesired orientation alone to keep the firearm from firing.
The control system of the firearm sensor system further generally will communicate with a fire control, trigger system and/or a safety system for the firearm. The control system can include a separate control system mounted within the frame, stock, receiver or other portion of the firearm, or can be included as part of a firearm control system of an electronic firearm such as disclosed in U.S. Pat. No. 5,755,056, the disclosure of which is incorporated herein by reference. The control system blocks or permits the firing sequence to proceed depending on a sensor output signal.
The halting of the firing sequence is accomplished in firearms that are electrically initiated by the control system issuing an interrupt signal to stop the transmission of a firing pulse to a round of electrically activated ammunition. The sensor system of the present invention also could be applied to a conventional percussion firearm as well, such as by controlling a solenoid-activated stop to hold a firing pin in a ready to fire position and block a percussion type fire control from imparting or releasing its energy to a round of percussion ammunition to initiate a firing sequence.
Various objects, features, and advantages of the present invention will become apparent to those skilled in the art upon a review of this specification when taken in conjunction with the accompanying drawings.
Turning now to the drawings in which like numerals indicate like parts throughout the several views, the present invention relates to a firearm sensor system 10 for a firearm F for sensing a fault condition, such as the firearm experiencing a jarring event, application of force or undue acceleration, or for sensing movement of the firearm into an unsafe or undesired orientation, and preventing the firearm from being fired upon detection of such an unsafe or fault condition. As shown in
The firearm sensor system 10 generally includes one or more sensor arrays 15 having one or more sensors 16 for sensing jarring events or application of force or undue acceleration of the firearm, and/or determining the orientation of the firearm. The sensor arrays 15 generally are mounted at a desired location or locations within the body of the firearm, typically within the stock 17 of a rifle as indicated in
As shown in
A preferred embodiment of the firearm sensor system 10 would include both a drop/jar sensor system 27 (
In one embodiment, the firearm sensor system 10 includes drop/jar sensor system 27 (
For detecting jarring forces and/or undue acceleration of the firearm, the sensors 16 of the drop/jar sensor system 27 generally will include one or more acceleration sensors 30 (
Additionally, the examples in
Inertia or acceleration switches are available with normally open or normally closed contacts. Normally closed contacts generally are preferred because it takes less time for the normally closed contacts to open than it does for normally open contacts to close, although other types of switches also can be used. Normally closed contacts are opened as the firearm is subjected to a jarring force and/or acceleration sufficient to cause a contact or contacts of the switches to separate or open. The inertia or acceleration switches further can be wired in series so as to function as single switch such that if any of the inertia or acceleration switches is opened as a result of an acceleration or jarring force being detected that exceeds a predetermined acceleration switch 31 threshold, the sensor array will indicate a fault condition. If normally open switches are used, the switches can be wired in parallel to work as one switch. Six orthogonally mounted uni-directional switches can be configured to make an omni directional sensor as shown in
Momentary contact acceleration switches further generally are preferred such as, for example, a Select Controls, Inc. extended TO-18 configuration acceleration switch, which can be custom built with any activation level from about 0.5 to 10,000 G's. The activation level of the acceleration switches used sets the threshold level of acceleration. To change the desired threshold level of acceleration requires that new acceleration switches with the desired activation level should be used. Typical handling of firearms produces accelerations of less than eight G's. A typical long gun being dropped from a height of approximately one inch onto a one inch rubber mat typically produces accelerations in excess of fifteen G's. Based on this information, a preferred threshold level or range of acceleration required for activation can be set at about ten G's. The threshold level is however, arbitrary and should be set to be higher than levels that would occur during normal handling and lower than any event that could cause a false trigger, and will further vary based on firearm platform and/or uses. The acceleration associated with acquiring moving targets can be minimized by locating the acceleration switches in the stock close to the recoil pad as shown in
It further will be understood that while inertia switches or acceleration switches are disclosed for use in the present invention, they are not the only technology that can be used with the drop/jar sensor system 27 (
In addition, it will be understood by those skilled in the art that various other types of sensors as known in the art that can be made to sense and/or distinguish acceleration or application of force resulting from unnecessary, rapid acceleration or a jarring of a firearm, also can be used as part of the firearm sensor system 10 of the present invention for stopping or blocking the firing sequence of the firearm to prevent inadvertent discharge. It would also be possible to use a mass suspended from a cantilevered beam, such as mounted within the receiver or frame of the firearm, or the firearm stock, which has a strain gauge or other force sensor or detector mounted thereon as shown in
In addition, or in the alternative, the firearm sensor system 10 of the present invention can further include an orientation sensor system 28 in which the sensor arrays 15′ include a series of orientation sensors 35 arranged in an array so as to be capable of measuring or sensing the orientation of the firearm along two or more axes relative to the earth. Typically, such an orientation sensor array 15′ will include magnetometers 36, as shown in
The array of orientation sensors 35 generally will measure the orientation of the firearm in terms of its angle relative to at least two predetermined axes relative to the earth. The first axis of measurement generally is the inclination or elevation of the firearm with respect to the earth. The second axis of measurement generally will include what shooters typically refer to as “cant”, which is equivalent to the firearm being rotated about an axis 38 extending along the bore of the firearm barrel 39. The orientation sensors 35 can be set with a predetermined threshold range or limit, such as in the context of using tilt or tip-over switches 29 as shown in
An example of a preferred orientation sensor 35 would include the Applied Physics Systems Model 544 Miniature Angular Orientation Sensor. The Model 544 uses a three axis fluxgate magnetometer and a three axis accelerometer to sense orientation. The Model 544 is also equipped with an analog to digital converter and microprocessor subsystem. The microprocessor processes the raw signals from the accelerometer and fluxgate magnetometer into a 16 bit digital signal that represents the inclination, cant, and azimuth orientation angles. In addition, the Model 544 should be isolated from the shock induced by recoil of the firearm such as by mounting the sensor to the firearm with a shock absorbing material. Examples of suitable shock absorbing materials include rubber, neoprene, styrene and other, similar lightweight dampening or shock absorbing materials.
The azimuth angle of orientation is equivalent to the angle one would get from reading a compass, and is not necessarily required for the operation of the sensor system. The inclination angle of orientation is the angle between the earth and axis of the barrel. Zero inclination generally is defined by the barrel of the firearm being horizontal and the trigger being located below the axis of the barrel. The inclination angle increases as the muzzle end of the barrel is raised relative to the opposite end. The cant orientation angle is a measure of the firearm's angled rotation about the axis of the barrel. The cant angle is equal to zero when the trigger is directly below the axis of the barrel. A clockwise rotation about the axis of the barrel when viewedfrom the butt stock end causes the angle to increase.
The threshold limits for orientation sensor system 28 are arbitrary and depend on the intended use of the firearm. For example, the expected safe operating orientations of a shotgun used for upland bird hunting typically will be different than those expected for centerfire rifle used to hunt deer, and different still for most handgun use. A preferred inclination operating range for a shotgun is from approximately negative 90 degrees to approximately positive 90 degrees. A centerfire rifle preferred inclination operating range is from about negative 90 degrees to about positive 45 degrees. A preferred cant operating range for both shotguns and rifles generally is from about negative 45 degrees to about positive 45 degrees. These operating ranges can be further varied as needed depending on the type of firearm (i.e., rifle, shotgun, or handgun) and its intended environments/uses.
It will also be understood that the present invention is not limited only to the use of an Applied Physics Systems Model 544, but rather that various other, alternative sensors also can be used as discussed above with their outputs processed into an orientation signal, including the use of three-axis fluxgate magnetometers and three-axis accelerometers as separate individual components. The signals generated by the magnetometer and accelerometer are sent to a controller or processor 40 of the control system 25 to be processed into cant, inclination, and azimuth orientation angles. The three-axis magnetometer can include a single unit or can consist of three orthogonally mounted single axis magnetometers. Similarly, the three-axis accelerometer may consist of three single axis accelerometers orthogonally mounted.
The orientation or jar/drop sensors or sensing technologies used also can be either analog or binary in nature. Tilt or tip-over switches 29 are an example of a binary sensor.
Preferably, the firearm sensor system 10 of the present invention will prevent or block the completion of a firing sequence of the firearm so that the firearm is kept from firing if the firearm has experienced a jarring or force event or undue acceleration, and/or is in an improper or unsafe orientation. It will, however, be understood that the firearm sensor system 10 of the present invention does not need to monitor both conditions in order to act to prevent the firing of the firearm. In further embodiments of the invention, it is possible that the firearm sensor system could be used to sense only acceleration or a jarring event acting on the firearm to stop the firing sequence, or alternatively, the firearm sensor system could be designed to sense and stop or block the firing sequence of the firearm when the firearm is simply moved into an undesired or unsafe orientation.
The control system 25 (
Typically, as illustrated in
In addition, as illustrated in
The output signal(s) 57/57′ from the comparator(s) can be a false signal, which is where the threshold reference signal exceeds the sensor sigial, thus indicating that the firearm is in a safe to fire condition, or it can be a true signal such as where the sensor signal exceeds the threshold reference signal so as to indicate to the firearm control system 41 that a fault condition has been detected by the sensor array. The threshold reference can be set at a predetermined level, or can be set at a zero value such that any signal received from the sensor array that is in excess of a zero voltage level would indicate a fault condition. By setting the level of the threshold reference signal, the system can be set for greater or lesser sensitivity to jarring, acceleration events, and/or improper orientations.
The threshold reference signals also can be set at variable levels so that an acceptable amount of movement or jarring of the firearm would be permitted, which generally would be significantly less than a level sufficient to cause the firearm to discharge, such as during normal handling and aiming of the firearm to prevent a shutdown of the system and blocking of the firing sequence of the firearm under inappropriate circumstances. For example, in monitoring the inclination orientation angle of the firearm, the upper threshold reference could be set at a value or range somewhere in excess of 90-135° from a horizontal axis relative to the earth, although greater or lesser threshold angles can be set as desired, such that as the shooter is tracking a shot, such as a bird flying overhead, the firearm will not be inadvertently disabled, unless the firearm is moved into an unsafe orientation, such as being turned upside down or other undesirable orientation. Similarly, the threshold reference signals can be set to allow the firearm to be moved rapidly to a desired position for firing, such as when tracking a moving target, and still prevent an accidental discharge from ajar-off.
SAAMI (Sporting Arms and Ammunition Manufactures Institute) specifies that new rifles and shotguns must pass a jar-off test of dropping a ready to fire rifle or shotgun from a height of 12 inches onto a one inch rubber mat. Observed accelerations from doing this typically are several hundred Gs. Accelerations as high as eight G's have been observed in normal handling. A ten G acceleration threshold is suggested to provide the maximum amount of jar-off protection without interfering with the normal operation of the firearm. After receiving the output signal(s) from the comparator(s), the firearm control system will, in response, either issue a firing signal 61 to allow the firing sequence of the firearm to proceed or will prohibit the firing sequence from proceeding. Thus, if the firearm sensor system detects that the firearm has been dropped or experienced some other jarring or force event or misorientation of the firearm, the firearm control system 41 (
For example, when an electronic firearm firing electrically primed or actuated ammunition, upon receipt of a trigger signal, the firing sequence of the firearm will proceed, such as disclosed in U.S. Pat. No. 5,755,056, which is incorporated herein by reference, wherein the system controller of the electronic firearm will direct a firing pulse or charge through an electrically conductive firing pin or probe 23 (
It also will be understood by those skilled in the art that the sensor system of the present invention also can be used in a conventional firearm used for firing percussion-primed ammunition 66 (
This embodiment of the control system 25 only shows the use of one shock sensor, but it will be understood that additional axes of drop/jar detection can be added by the addition of additional properly oriented shock sensor, a precision instrumentation amplifier 47, and two threshold references or signals and comparators for each additional axis. A total of three axes generally would be sufficient to sense any drop/jar event. However, drop/jar events that do not occur aligned with one of the axes can require a higher acceleration to occur before sensing a drop/jar event. The worst case occurs when the direction of the jar event is about 54.74 degrees from each of the three orthogonal axes. This worst-case condition requires that 17.32 G drop/jar event to occur to initiate a 10 G threshold in any of the three axes. This could be addressed by processing the three shock sensor signals into one common signal that represents the total magnitude of the drop/jar event. However, this is not needed as long as the threshold reference level is sufficiently lower than the level of acceleration selected that will cause ajar induced trigger signal to be created.
The control processor 40 of the control system 25 also generally requests orientation information from the orientation sensor. If the cant and inclination orientation angles are within normal safe operating range the control processor 40 produces a false illegal orientation signal 58 and the firearm control system 41 generates the firing signal or pulse or energizes the solenoid as indicated at 61/62. If either the cant or inclination orientation angles are outside the normal safe operating range the control processor 40 produces a true illegal orientation signal and the firearm control system 41 prohibits the generation of a firing pulse or de-energizes the solenoid. This embodiment of the control system typically would only block the firing pulse or signal from being generated while either the cant or inclination angles are out of the normally safe operating range. It is also possible to block the generation of the firing pulse or signal after the illegal orientation signal has been received until the user has cleared the error through cycling the safety, battery removal and reinsertion, reset button, or the like. The illegal orientation generally is only checked upon the trigger system 42 signaling that the trigger has been pulled. The firearm control system 41 will ignore any illegal orientation signals received during the recoil event associated with actually firing a round. This will be achieved by neglecting the illegal orientation signal for a desired delay, for example, 200 ms, after initiating a round of ammunition.
The delay time typically is chosen so that a delay in the jar sensors signaling that a jar event has occurred will not allow a jar induced trigger signal to fire a round of ammunition. Testing of acceleration switches, such as the Select Controls Inc. 3088-1-000, has indicated an average of 0.64 milliseconds of delay between an acceleration event and the acceleration switch signaling the event. The greatest observed delay in the acceleration switch signaling the acceleration event was about 1.0 millisecond. As the magnitude of acceleration of the jar event increases, the delay time between the jar event and acceleration switch signaling the event decreases. It also appears that the activation level of the acceleration switches is sufficiently low as to generally require a considerable increase in magnitude of acceleration of the jar event before there is a risk of a jar induced trigger event. Based on this information it is suggested that the delay time be set at approximately one millisecond, although greater or lesser delay times also can be used depending on the types of sensors used and applications of the firearm(s).
A further operational embodiment, as shown in
The example control system of
The control system begins by initially resetting a software based delay counter as indicated at 125, after which the firearm safety (step 126) is checked to determine whether the safety is engaged. If the safety is not engaged the control system then checks to see if a trigger event has occurred (step 127), and if so, a further check is made of the instantaneous orientation of the firearm, as shown at 128. If this orientation is acceptable the round is fired, as shown at 129, but if the orientaion is found to be improper or unsafe, a fault condition is registered and an orientation illegal/error message or signal is provided as indicated at 131, after which the system generally must be reset (shown at 132) before continued operation.
If a trigger event (127) has not occurred a delay counter is examined to determine if the polling delay has elapsed as indicated at 133. If not, the sequence increments the delay counter (134) and returns to repeat the process beginning with checking the firearm safety (step 126). If the polling delay has elapsed, the current firearm orientation is obtained from the orientation sensor (elevation and/or cant) as shown at 135, and the change in movement measured or detected from the last polling is determined by subtracting the prior polling data from the most recent polling data, which measured change in movement is then divided by the polling delay time to determine the average rate of change of elevation (and/or the average rate of change of cant) as shown in step 136. These rates of change are then compared to stored or programmed rate of change thresholds to determine if the firearm has been “moved too rapidly” during the last polling period (step 137). If the rate of change does not exceed the threshold then processing continues at the operation start point with a reset of the polling delay counter (125) and the process or sequence of the system continues as above. If the rate of change exceeds the threshold then the firearm is disabled or otherwise blocked from firing, an appropriate display error is posted (131), and the firearm then enters an inactive or disabled state pending a reset event (step 132). The shorter the polling delay time, the better the resolution of rate of change detection and as such, the polling delay time generally should be set to be slightly greater than the acquisition time required by the orientation sensor itself, for example, typically about 130 to about 200 milliseconds.
It will be understood by those skilled in the art that while the present invention has been described above with reference to preferred and alternative embodiments, various modifications, additions and changes can be made to the present invention without departing from the spirit and scope of this invention as set forth in the following claims.
The present application claims the benefit of the priority of U.S. Provisional Application Ser. No. 60/293,394, filed May 24, 2001.
Number | Date | Country | |
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60293394 | May 2001 | US |
Number | Date | Country | |
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Parent | 10152916 | May 2002 | US |
Child | 10878216 | Jun 2004 | US |