Anti-dry fire keyway trigger system for crossbows

Abstract

A Keyway Trigger System with a dry fire prevention nock is provided for use in a crossbow. The System ensures proper, full engagement of the dry fire prevention nock with a crossbow string such that the crossbow will only fire when an arrow is loaded correctly. The nock is received in a slotted opening forming a keyway adapted to be engaged by surfaces of the profiled dry fire prevention nock such that only when an arrow is properly loaded into the keyway, aligned with trigger latch members and fully engaged with the crossbow string then the trigger moves from a non-firing position to a firing position allowing the arrow to be fired. The Keyway Trigger System prevents dry fire and partial dry fire, eliminates risk of damage to the crossbow, eliminates potential risk of injury to a user, and improves accuracy and reliability of the flight trajectory of the arrow.

The invention claimed is: 
     
         1 . A system for preventing full and partial dry fires of a crossbow, comprising a crossbow trigger mechanism including:
 a trigger housing;   a trigger latch component moveable between a crossbow string retaining position and a crossbow string releasing position;   a trigger assembly mounted in said trigger housing and operatively engaged with said trigger latch component;   an anti-dry fire lever moveable between a first position aligned with said trigger latch component to a second position behind and below a cocked crossbow string;   a keyway opening in said trigger latch component formed by said anti-dry fire lever and a plurality of nock-contacting surfaces within said trigger latch component; and   a dry fire prevention nock received in said keyway opening wherein said dry fire prevention nock includes a forward portion for affixing to an arrow and a rearward portion terminating at a pair of spaced, opposed wings forming a U-shaped opening to receive said crossbow string therein and where said wings extend behind said crossbow string when said crossbow string is received in said U-shaped opening therein permitting said dry fire prevention nock to be seated against said crossbow string, causing said anti-dry fire lever to pivot downwardly to said anti-dry fire lever said second position, when said dry fire prevention nock is fully inserted into said keyway opening causing said anti-dry fire lever to move from said first position into said second position thereby releasing said trigger latch to said crossbow string releasing position whereby said crossbow is ready to be fired.   
     
     
         2 . The system for preventing full and partial dry fires of a crossbow as claimed in  claim 1 , further comprising a safety lever mounted in said trigger housing;
 said safety lever movable between a first safe position and a second firing position;   said safety lever movable manually into and out of engagement with a trigger block of said trigger assembly; and   said trigger block movable between a first non-firing position and a second firing position.   
     
     
         3 . The system for preventing full and partial dry fires of a crossbow as claimed in  claim 1 , wherein said trigger latch further comprises two downwardly extending trigger latch prongs which include a plurality of nock contacting surfaces. 
     
     
         4 . The system for preventing full and partial dry fires of a crossbow as claimed in  claim 3 , wherein said anti-dry fire lever includes an upwardly projecting tapered prong:
 said upwardly extending projecting tapered prong includes a nock-contacting upper edge surface; and   said first downwardly extending prong and said second downwardly extending prong and said upwardly extending projection forming said keyway opening.   
     
     
         5 . The system for preventing full and partial dry fires of a crossbow as claimed in  claim 1 , wherein said anti-dry fire lever further comprises:
 a first upper edge surface portion to engage a stop of a front vertical face of said trigger latch when no arrow is loaded in the crossbow to prevent movement of said trigger latch to said crossbow string releasing position; and   a second upper edge surface portion to engage an arrow nock such that when an arrow nock is loaded into the crossbow, said first upper edge surface portion is moved downwardly away from said stop to permit movement of said trigger latch component to said crossbow string releasing position.   
     
     
         6 . The system for preventing full and partial dry fires of a crossbow as claimed in  claim 2 , further comprising a safety lever actuating link, wherein said safety lever actuating link engages said safety lever to position said safety lever in said first safe position. 
     
     
         7 . The system for preventing full and partial dry fires of a crossbow as claimed in  claim 6 , further comprising a sear movable between a first de-cocked position and a second cocked position, wherein said sear engages said trigger block to position said trigger block in said second firing position. 
     
     
         8 . The system for preventing full and partial dry fires of a crossbow as claimed in  claim 6 , wherein rotation of said trigger latch component into said crossbow string retaining position when said crossbow string is received in said trigger latch causes said safety lever actuating link to move said safety lever into said second firing position. 
     
     
         9 . The system for preventing full and partial dry fires of a crossbow as claimed in  claim 1 , wherein said dry fire prevention nock has a variable diameter from an intermediate portion to a shoulder portion. 
     
     
         10 . A dry fire prevention nock received in a keyway trigger system for preventing full and partial dry fires of a crossbow, comprising:
 a first portion including a front cylindrical element to be attachably received at a cylindrical aperture located at a rear end of an arrow; and   a second portion extending laterally from said first cylindrical portion and terminating at a U-shaped opening, said U-shaped opening to receive a crossbow string therein.   
     
     
         11 . A dry fire prevention nock received in a keyway trigger system for preventing full and partial dry fires of a crossbow as claimed in  claim 10 , wherein said second portion of said dry fire prevention nock includes a flat right side and a flat left side, said flat right side and said flat left side are parallel. 
     
     
         12 . A dry fire prevention nock received in a keyway trigger system for preventing full and partial dry fires of a crossbow as claimed in  claim 11 , wherein said second portion of said dry fire prevention nock has a curved top side and a curved bottom side. 
     
     
         13 . A dry fire prevention nock received in a keyway trigger system for preventing full and partial dry fires of a crossbow as claimed in  claim 10 , wherein said second portion of said dry fire prevention nock is inserted into said keyway trigger system. 
     
     
         14 . A dry fire prevention nock received in a keyway trigger system for preventing full and partial dry fires of a crossbow as claimed in  claim 10 , wherein said second portion of said dry fire prevention nock has a profile configuration including said U-shaped opening, said flat right side, said flat left side, said curved top side and said curved bottom side, wherein said profile allows said nock to pass through a keyway opening of said keyway trigger system. 
     
     
         15 . A dry fire prevention nock received in a keyway trigger system for preventing full and partial dry fires of a crossbow as claimed in  claim 14 , wherein said second portion of said dry fire prevention nock profile configuration allows said U-shaped opening to engage said crossbow string wherein said U-shaped opening of said second portion of said dry fire prevention nock biases said crossbow string into engagement with said dry fire prevention nock. 
     
     
         16 . A dry fire prevention nock received in a system for preventing full and partial dry fires of a crossbow as claimed in  claim 10 , wherein said second portion of said dry fire prevention nock is slidably received in a keyway opening of said keyway trigger system. 
     
     
         17 . A system of preventing full and partial dry fires of a crossbow, comprising: a crossbow trigger mechanism further comprising:
 two downwardly oriented trigger latch prongs of a trigger latch component moveable between a first string retaining position and a second string releasing position;   one upwardly oriented anti-dry fire prong of an anti-dry fire device moveable between a first unlocked position and a second locked position;   said one upwardly oriented anti-dry fire prong located intermediate to said two downwardly oriented trigger latch prongs; and   said downwardly oriented trigger latch prongs and said upwardly oriented anti-dry fire prong form a keyway to receive a dry fire prevention nock of an arrow therein.   
     
     
         18 . A system for preventing full and partial dry fires of a crossbow as claimed in  claim 17 , wherein said dry fire prevention nock of an arrow engages a crossbow string at a location behind said two downwardly extending trigger latch prongs and said upwardly extending anti-dry fire prong to cause said anti-dry fire device to move to said first unlocked position.