Note: Descriptions are shown in the official language in which they were submitted.
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AUTOMATIC WEAPON USER IDENTIFICATION AND SAFETY MODULE
FIELD OF THE INVENTION
The present invention relates to an automatic weapon user identification and
safety module.
DESCRIPTION OF THE PRIOR ART
One of the dangers associated with firearms is that they may be operated by
a person other than the owner of the firearm. In the context of the present
invention, this other person will be hereinafter referred to as "unauthorized
user" and the owner, or person authorized to operate the firearm will be
hereinafter referred to as "authorized user".
A situation which all too frequently arises is that a firearm is taken from a
police officer (the authorized user) by an unauthorized user and used against
the police officer, resulting in injury or death. However, it should be
understood that the present invention is equally applicable to any other
situation where an unauthorized user takes control of a firearm.
Many patents have been proposed to attempt to solve this problem. These
patents describe different safety mechanisms to prevent the discharge of a
firearm by an unauthorized user.
For example, U.S. Pat. No. 5,713,149 describes a keypad interface located
on the firearm, with a trigger lock system using a solenoid. In order to
enable
the firearm, the user must punch a code into the keypad. However, this
mechanism reduces the effectiveness of the firearm in emergency situations
and does not prevent the firearm from being used by an unauthorized user
once the firearm is enabled.
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Biometric systems have also been proposed for authorized user recognition.
These systems verify the fingerprint or the voice of the authorized user prior
to enabling the firearm, which is usually disabled. Examples of these systems
can be found in U.S. Pat. Nos. 5,603,179 and 5,560,135. Typically, these
systems enable the firearm when the user is approved by a recognition
interface which compares a measured sample with a memorized template in
the firearm. The drawback of these systems is that, for example, a police
officer requires that the firearm be enabled immediately, particularly when
facing a suspect. Fingerprint and voice recognition systems still have a high
probability of rejecting the authorized user due to an incorrect measurement,
or large variations in the biometric sample (due to, for example, stress),
which can have disastrous effects for the police officer. Furthermore, these
systems require more response time depending on the accuracy and
precision of the recognition template.
Another example of a safety system is U.S. Pat. No. 4,682,435 where the
firearm is normally enabled. The system consists of a remote transmitter
carried by the authorized user which uses RF communications to disable the
firearm. A receiver is integrated in the firearm with a locking mechanism
using a solenoid to disable the firing pin or to block the trigger bar. The
user
is expected to disable the firearm by triggering the RF signal, which is
unsafe
in an emergency situation or in the case where the authorized user is
unconscious.
Yet another example of a safety system is disclosed in U.S. Pat. No.
5,168,114. The system consists of a remote RF transmitter worn by a user
and a receiver incorporated in the firearm. The locking mechanism is a
solenoid electrically connected to the receiver. The firearm is normally
disabled and the locking mechanism will unlock the firearm only when the
transmitter, held or worn by the authorized user, is located at a
predetermined distance from the firearm. The firearm will not fire if the
receiver is unable to properly receive the coded RF signal from the
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transmitter. In this system, the transmitter transmits continuously and the
locking system enables and disables the locking system depending on the
distance between the firearm and the transmitter. This system has an
important drawback in that the transmitter consumes a great amount of
power since it is continuously transmitting. Accordingly, small batteries,
suitable for incorporation into a small transmitter and receiver, are not
adequate to provide long operational life.
U.S. Patent 5,953,844 describes a similar system, making use of a motion
detector on the trigger of the firearm. The trigger detector requires
authentication of the user each time that the firearm is discharged and this
authentication must be carried out in a very short time if it is not to
interfere
with the firearm use. This leads to high power consumption and a severe
limitation on the time allowed for encryption, anti-jamming protocols, and
mechanical blocking of the trigger.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an automatic weapon
safety module where power consumption is reduced. In accordance with the
invention, this object is achieved with a module comprising a unit integral
with
a firearm. The unit includes handgrip detection means operatively associated
with the handgrip of a weapon for detecting the preparation of the weapon for
use by the user grasping the handgrip. The unit also comprises transceiver
means, preferably RF, operatively associated with the handgrip detection
means for sending a coded signal when the handgrip detector on the
handgrip has been activated. The coded signal is received by at least one
remote token which receives the coded signal and transmits a coded
acknowledgement signal upon receipt of the coded signal. Means for
enabling and disabling the weapon are operatively associated with the
RF transceiver means for allowing operation of the trigger and thereby the
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firing of the weapon when the coded acknowledgement signal has been
received by the transceiver means.
Preferably, the system includes at least one token worn by an authorized
user. In this case, the unit integral to the weapon further uses a collision
avoidance technique to discriminate between the different signals sent by
more than one token. Also preferably, the integral unit uses an anti-jamming
technique.
In another aspect of the invention, the system is used in a firearm using
electronic ammunition.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention and its advantages will be more easily understood
after reading the following non-restrictive description of preferred
embodiments thereof, made with reference to the following drawings in
which:
FIG. 1 is a schematic representation of an firearm incorporating the system
according to a preferred embodiment of the invention;
FIG. 2 is a top plan view of a token for use with the system according to the
preferred embodiment of the invention incorporated into a bracelet;
FIG. 3 is a side view of the bracelet of FIG. 2;
FIG. 4 is a schematic representation of the trigger movement detection
means associated with the trigger of a firearm;
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FIG. 5 is a schematic representation of the handgrip detection means
associated with the handgrip of a firearm;
FIG. 6 is a schematic representation of the components of the unit integrated
in the firearm; and
5
FIG. 7 is a schematic representation of the components of the token.
DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
As mentioned above, the invention is directed to an automatic safety system
for a weapon 1. In the context of the present invention, weapon includes
firearms such as rifles, handguns, pistols, etc., and also includes stun guns,
and, more broadly, any weapon which includes a handgrip for a user to grip.
The invention may easily be adapted to any type of weapon 1, with the
proper modifications. For the purposes of explaining the functioning of the
present invention, it will be described as incorporated in a handgun 1, shown
in FIG. 1. The handgun 1 has a barrel 3, a handgrip 5, a trigger 7 and a
firing
mechanism, all of which are well known. However, it should be understood
that the following description is equally applicable for any type of weapon.
The system according to a preferred embodiment thereof includes a unit
which is integrated into the firearm 1, and at least one token 40 which is
remote from the firearm 1. The unit which is integrated into the firearm is
sometimes referred to as a "master", and the token, a "slave".
The unit includes handgrip detection means 21 operatively associated with
the handgrip 5 of the firearm 1, for detecting the presence or absence of the
user's hand on the handgrip 5. Such handgrip detection means 21 are readily
available and can take the form of a mechanical switch, position sensor,
motion sensor, pressure sensor, capacitive sensor, temperature sensor,
optical detector, etc., as long as the handgrip detection means 21
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immediately respond to presence of the user's hand on the handgrip 5. As
mentioned previously, the handgrip detection means 21 are integral with the
firearm 1. The trigger detection means 20 are shown in the same diagram.
Trigger detection means 20 are readily available and can take the form of a
mechanical switch, position sensor, motion sensor, pressure sensor,
capacitive sensor, temperature sensor, optical detector, etc., as long as the
trigger movement detection means 20 immediately respond to trigger
movement.
An aspect of the invention lies in the use of a hand-grip detection device to
initiate the authentication sequence. Hand-grip detection occurs early in the
cycle of preparation for use of the firearm and several hundred milliseconds
are available to the system to perform authentication. Hand-grip detection
can be very reliable and impervious to errors caused by the wearing of
gloves, the 'handedness' of the user, or other operational issues. Handgrip
detection also implies that the user of the firearm is only authenticated
once,
when the firearm is prepared for use. In weapons with large ammunition clips
this drastically reduces the power required by the authentication circuit and
increases the operational life of the circuitry. In such a case, when
authentication is performed only once, the unit integral with the weapon
places itself into a sleep mode and the weapon is operational until the
handgrip is let go (i.e. the handgrip detector is disabled).
The unit also includes transceiver means 30, preferably RF, operatively
associated with the handgrip detection means 21 for sending a coded signal
when the handgrip or trigger detector has been activated. The transceiver
means 30 are integral with the firearm, and are preferably located in the
handle 5 of the firearm 1, or, alternately, are included with a magazine for a
firearm. The transceiver means 30 are better shown in FIG. 5, preferably
include an antenna 31, a receiver 33 coupled to the antenna 31, an
encoding/decoding module 35 and a transmitter 33 coupled to the antenna
31 for sending the coded signal. In a preferred embodiment shown in FIG. 5,
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the receiver 33 and the transmitter 33 are incorporated into a single
interface.
The transceiver means 30 also includes power means, such as a battery 32,
for powering the transceiver means 30.
In a preferred embodiment of the invention, the transceiver means are
integral with the weapon. The battery is preferably part of the magazine,
allowing for quick battery replacement in the field.
The system further includes at least one token 40 for receiving the coded
signal and for transmitting a coded acknowledgement signal upon receipt of
the coded signal. The at least one token 40 is separate from the firearm 1,
but nonetheless located in close proximity thereof. The token 40, as better
shown in FIGS. 2, 3 and 6, includes an antenna 41, a receiver 43 coupled to
the antenna 41 for receiving the coded signal generated by the transceiver
means 30, an encoding/decoding module 45 for creating a coded
acknowledgement signal and a transmitter 43 coupled to the antenna 41 for
transmitting the coded acknowledgement signal. In a preferred embodiment
shown in FIG. 6, the receiver 43 and the transmitter 43 are incorporated into
a single interface. The token 40 also includes power means, such as a
battery 42, for powering the token 40.
Preferably, the system only works if the token 40 is located in close
proximity
to the firearm 1. Accordingly, both the transceiver 30 and the token 40 can be
programmed to respond to the coded signal and to the coded
acknowledgement signal when the signal strength is above a predetermined
threshold, indicating proximity. Typically, this proximity is no greater than
approximately 45 cm (or 18 inches).
The system also includes means 50 for locking and unlocking the trigger
operatively associated with the transceiver means 30 for allowing operation
of the trigger and thereby the firing of the firearm when the coded
acknowledgement signal has been received. The means 50 for locking and
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unlocking include an enable/disable switch, so that the trigger can be
normally disabled (for example in the case of a firearm which is in a house,
so that unauthorized users cannot fire the firearm) or normally enabled (for
example for a police officer). It should be noted that the means 50 for
locking
can take the form of a trigger lock, a pin lock or a hammer lock.
Alternately, in the case where the firearm uses electronic pulses to fire, the
system includes means 51 for blocking or passing the electronic pulses used
to fire the ammunition and operatively associated with the transceiver means
30 for allowing operation of the firearm when the coded acknowledgement
signal has been received. The means 51 for blocking or passing the
electronic firing pulses include an enable/disable switch, so that the firing
pulses can be normally disabled (for example in the case of a firearm which
is in a house, so that unauthorized users cannot fire the firearm) or normally
enabled (for example for a police officer).
One of the advantages of the present invention lies in the bi-directional
communication between the transceiver 30 and the token 40. This bi-
directional communication considerably reduces the power consumption
required, since the system will be used only when the handgrip detector on
the handgrip 5 has been activated, i.e. only when a person wishes to prepare
the firearm 1 for use.
Accordingly, the communication protocol between the transceiver 30 and the
token 40 is done through RF. When the handgrip 5 is seized by the user and
the handgrip detector 21 is activated or if the trigger detector is activated,
the
transceiver 30 transmits a coded RF signal. Preferably, this coded signal is
encrypted, using known encryption techniques and a secret key 37. The
token 40 receives the coded signal and decrypts it using a secret key 37,
again using known decryption techniques. If the received request is valid,
i.e.
if it uses a secret key known to the token 40, then the token 40 transmits an
encrypted acknowledgement back to the transceiver 30. Upon receipt and
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decoding, i.e. decrypting of the acknowledgement signal, the transceiver 30
changes the state of the electronic blocking means 50. It should be
understood that the blocking/unblocking step depends on the state of the
electronic blocking means 50, i.e. enabled or disabled. If the electronic
blocking means 50 are disabled, then the receipt of the valid
acknowledgement signal will enable it, meaning that the electronic firing
pulses will be permitted to fire the firearm when the trigger is pulled.
However, if the electronic blocking means 50 are enabled, they will remain
enabled upon receipt of a valid acknowledgement signal and will be disabled
if there is no acknowledgement, or if it is invalid.
The bi-directional nature of the communication also increases the safety of
the firearm 1, since an acknowledgement signal is requested each time the
handgrip 5 is seized or the trigger detector is actuated.
Other features may be incorporated in the system according to the present
invention by transmitting additional information from the transceiver 30 to
the
token 40, such as status of the firearm 1 after each firing cycle, the number
of
shots fired, battery status etc. Of course, if such information is
transmitted,
the token 40 is preferably equipped to either store the information for future
downloading, or to display such information on an LCD display 61, or both.
As mentioned previously, an authorized user may carry more than one token
40. In such a case, the communication protocol must include anti-collision
detection and resolution in the communication protocol, in order to
differentiate between the various tokens 40, and accept a coded
acknowledgement signal only from one of them. This is the case, for
example, where a police officer is a two-handed shooter and carries a token
about each wrist. The anti-collision module will also be necessary where
many officers are present at a location, each carrying at least one token. If
the distances between each are relatively close, the transceiver 30 in the
firearm 1 will be receiving acknowledgement signals from all tokens and must
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be able to discern between them. It should be noted that the system
according to the present invention may also be enabled by more than one
token, and currently, the system supports up to 55 tokens for any given
weapon (or master).
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The technique that is proposed to prevent such a problem is a transmit and
stand-off technique. When a coded signal has been sent by the transceiver
30, all the tokens 40 transmit, for example, a pseudo-random sequence of
pulses and dead time to see if another token is actually transmitting. The
10 sequence could include 10 to 12 symbols of a random number generated by
the token 40. The transceiver 30, through a variety of known techniques such
as peak detection, synchronous detection, carrier detection or a combination
thereof, determines if there are one or more tokens 40 present, and selects
from which token 40 the coded acknowledgement signal must be received.
This technique is well known in the art.
Furthermore, the system must also be jamming-resistant, in order to ensure
communication between the token and the transceiver regardless of the
electromagnetic environment the authorized user is in.
The transceiver may also include a self-test to determine if a communication
fault is due to an internal problem or to the absence of a token within a
predetermined distance
Although the present invention has been explained hereinabove by way of a
preferred embodiment thereof, it should be pointed out that any modifications
to this preferred embodiment within the scope of the appended claims is not
deemed to alter or change the nature and scope of the present invention.
