Cartridge-in-chamber detection system for firearms

Abstract

The present invention relates to a cartridge-in-chamber detection system for firearms which is independent in situations where the user comes into contact with metal parts of the weapon or situations where said contact does not exist, to provide a reliable indication of the presence or absence of the cartridge in the chamber, where the system comprises means to, through a supply voltage, determine the variation of the electrical capacity between two possible states of the system, when there is no cartridge in the chamber and when there is a cartridge in the chamber, making use of at least one electrode, regardless of the grip performed by the user.

1 . A cartridge-in-chamber detection system for firearms which comprises at least one electrical contact which is connected by a sensor circuit to a microprocessor, wherein the at least one electrical contact is in electrical contact with a cartridge when said cartridge is in the chamber, being both elements, cartridge and the at least one electrical contact, and consequently the metal parts of the weapon which are in physical contact with the cartridge, electrically connected, and where the microprocessor, through the sensor circuit, detects the capacitive variation between the situation in which the at least one electrical contact is electrically connected to at least the metal parts of the weapon and the cartridge, and the situation in which the at least one electrical contact is not electrically connected to at least the metal parts of the weapon and the cartridge, thus making it possible to determine the presence or absence of the cartridge in the chamber respectively. 
     
     
         2 . The system of  claim 1 , wherein a first electrical contact is connected via the sensor circuit to the microprocessor, and a second electrical contact disposed in the chamber of the weapon, where the first electrical contact is in physical contact with the second electrical contact, and where the second electrical contact comes into physical contact with a shell of the cartridge when said cartridge is in the chamber, being both elements, cartridge and second electrical contact, and consequently the metal parts of the weapon that are in physical contact with the cartridge, electrically connected through the connection between the first electrical contact and the second electrical contact, and where the microprocessor, through the sensor circuit, detects the capacitive variation between the situation in which the first electrical contact is electrically connected to the second electrical contact, the metal parts of the weapon and the shell of the cartridge and the situation in which the first electrical contact is electrically connected to the second electrical contact, thus making it possible to determine the presence or absence of the cartridge in the chamber respectively. 
     
     
         3 .- 7 . (canceled) 
     
     
         8 . The system of  claim 1 , further comprising a first electrical contact disposed in a slide of the weapon that is connected via the sensor circuit to the microprocessor  4 , and a second electrical contact disposed in the slide, where the first electrical contact is coupled to the second electrical contact through an elastic element, so that when the cartridge is in the chamber, an extractor pushes the second electrical contact towards the first electrical contact, the elastic element adopting a compressed arrangement, both electrical contacts coming into physical contact, and consequently the metal parts of the weapon that are in physical contact with the cartridge, being electrically connected through the connection between the first electrical contact and the second electrical contact, whilst when the cartridge is not in the chamber, the extractor does not push the second electrical contact towards the first electrical contact, the elastic element regaining this way its expanded position, the first electrical contact being electrically insulated from the second electrical contact, the metal parts of the weapon, a shell of the cartridge and the extractor, where the microprocessor, through the sensor circuit, detects the capacitive variation between the situation in which the first electrical contact is electrically connected to the second electrical contact, the metal parts of the weapon, the shell of the cartridge and the extractor and the situation in which the first electrical contact is not electrically connected to the second electrical contact, the metal parts of the weapon, the shell of the cartridge and the extractor, thus making it possible to determine the presence or absence of the cartridge in the chamber respectively. 
     
     
         9 .- 10 . (canceled) 
     
     
         11 . The system of  claim 1 , further comprising a first electrical contact disposed in a bolt carrier of the weapon that is connected via the sensor circuit to the microprocessor, and a second electrical contact disposed in a bolt head where the first electrical contact is in physical contact with a third electrical contact disposed between the first electrical contact and the second electrical contact, where the second electrical contact comes into physical contact with a shell of a cartridge when said cartridge is in the chamber, being both elements, cartridge and second electrical contact, and consequently the metal parts of the weapon that are in physical contact with the cartridge, being electrically connected through the connection between the first electrical contact, the third electrical contact and the second electrical contact, and where the microprocessor, through the sensor circuit, detects the capacitive variation between the situation in which the first electrical contact is electrically connected to the second electrical contact, the third electrical contact, the metal parts of the weapon and the shell of the cartridge and the situation in which the first electrical contact is electrically connected to the second electrical contact and the third electrical contact, thus making it possible to determine the presence or absence of the cartridge in the chamber respectively. 
     
     
         12 . The system of  claim 11 , wherein the second electrical contact is at least partially disposed in the chamber. 
     
     
         13 . (canceled) 
     
     
         14 . The system of  claim 1 , wherein the microprocessor, through the sensor circuit, converts the capacitive variation into a voltage variation. 
     
     
         15 . The system of  claim 1 , wherein the microprocessor generates a square signal of preset frequency with which the capacity of the sensor circuit is charged to measure the capacity variations thereof. 
     
     
         16 . The system of  claim 1 , wherein the microprocessor captures the voltage provided by the sensor circuit, which is compared to a threshold voltage. 
     
     
         17 . The system of  claim 1 , wherein the microprocessor comprises a temperature sensor which measures the temperature in each reading of the microprocessor and makes a temperature compensation throughout a whole operating range. 
     
     
         18 . The system of  claim 1 , further comprising supply means. 
     
     
         19 .- 22 . (canceled) 
     
     
         23 . The system of  claim 1 , having a response time of less than 1 ms to determine if the cartridge is present in the chamber or not. 
     
     
         24 . (canceled) 
     
     
         25 . The system of  claim 1 , wherein the at least one electrical contact is in physical contact with the cartridge in the situation in which the at least one electrical contact is electrically connected to the metal parts of the weapon and the cartridge. 
     
     
         26 . The system of  claim 1 , wherein the at least one electrical contact is insulated with respect to the metal parts of the weapon. 
     
     
         27 . The system of  claim 1 , wherein the at least one electrical contact is a firearm's own element. 
     
     
         28 . The system of  claim 1 , wherein the at least one electrical contact is a firearm's own modified element. 
     
     
         29 . The system of  claim 1 , wherein the at least one electrical contact is an external element to the firearm. 
     
     
         30 . The system of  claim 1 , wherein the at least one electrical contact is located in the chamber. 
     
     
         31 . The system of  claim 1 , wherein the at least one electrical contact is located outside the chamber. 
     
     
         32 . The system of  claim 31 , wherein the at least one electrical contact is disposed in a handguard of the weapon. 
     
     
         33 . The system of  claim 1 , wherein the at least one electrical contact is not in physical contact with the cartridge in the situation in which the at least one electrical contact is electrically connected to the metal parts of the weapon and the cartridge.