Elastic projectile propulsion systems and methods

Abstract

An elastic projectile propulsion system deploys a plurality of springs that bias a common launching cord via a plurality of block and tackle pulleys. Each sheave of the pulley is coupled to the moveable end of a spring such that the force of each spring contributes to the energy imparted to a projectile by the launching cord without adding significant friction or inertial resistance.

What is claimed is: 
     
         1 . A propulsion device comprising:
 a) an elongated barrel member forming a cavity having an elongated barrel member proximal end and an elongated barrel member distal end, where the elongated barrel member proximal end engages a mounting stock,   b) a pair of forward spring members each having a forward spring member proximal end and a forward spring member distal end, the pair of forward spring members positioned within the cavity of the elongated barrel member wherein the distal ends of the forward spring members connect to a corresponding moveable brace and the proximal ends of the forward spring members connect to a moveable pulley blocks,   c) a pair of rearward spring members, each having a rearward spring member proximal end and a rearward spring member distal end, the pair of rearward spring members positioned within the cavity of the elongated barrel member wherein the distal end of the rearward spring members connects to the moveable pulley blocks and the proximal ends of the rearward spring members connects to the corresponding moveable braces,   d) at least one pair of forward pulleys, each forward pulley coupled to the forward spring member proximal ends and at least one rearward pulley, connected to each of the rearward spring member distal ends, and   e) a launching cord having a first end and a second end wherein the first end engages the forward pulley and second end engages the rearward pulley.   
     
     
         2 . The propulsion device of  claim 1  wherein the pair of forward pulleys and the rearward pulley comprise a counteracting block and tackle pulley which couples an elastic energy stored in the forward spring members and the rearward spring members when the launch cord is drawn rearward toward the stock connecting end of the barrel. 
     
     
         3 . The propulsion device of  claim 1  further comprising a rail interiorly positioned in the barrel member. 
     
     
         4 . The propulsion device of  claim 3  wherein the rail is configurable to vertically move while remaining stationary horizontally. 
     
     
         5 . The propulsion device of  claim 1  further comprising a cocking mechanism. 
     
     
         6 . The propulsion device of  claim 1  having a width of 12 inches or less. 
     
     
         7 . The propulsion device of  claim 1  further comprising a trigger assembly. 
     
     
         8 . The propulsion device of  claim 1  wherein the launching cord is wrapped three or more times around the distal pulley. 
     
     
         9 . The propulsion device of  claim 1  wherein the forward spring members and the rearward spring members are combined in parallel banks, wherein each bank engages one or more moveably pulley blocks. 
     
     
         10 . A linear archery system comprising:
 a) an elongated barrel member forming a cavity having an elongated barrel member proximal end and an elongated barrel member distal end, where the elongated barrel member proximal end engages a mounting stock,   b) one or more of a forward spring member each of the one or more forward spring members having a forward spring member proximal end and a forward spring member distal end, the one or more forward spring members positioned within the cavity of the elongated barrel member wherein the distal end of the one or more forward spring members connects to a moveable brace and the proximal ends of the forward spring members connect to a moveable pulley block,   c) one or more rearward spring members, each of the one or more rearward spring members having a rearward spring member proximal end and a rearward spring member distal end, the one or more rearward spring members positioned within the cavity of the elongated barrel member wherein the distal end of the one or more rearward spring members connects to the moveable pulley blocks and the proximal ends of the rearward spring members connects to the corresponding moveable brace,   d) one or more forward pulleys, each of the one or more forward pulleys coupled to at least one of the one or more forward spring member proximal ends and at least one rearward pulley, connected to the rearward spring member distal end, and   e) a launching cord having a first end and a second end wherein the first end engages the forward pulley and second end engages the rearward pulley.   
     
     
         11 . The linear archery system of  claim 10  further comprising a rail interiorly positioned in the barrel member. 
     
     
         12 . The linear archery system of  claim 11  wherein the rail is configurable to vertically move while remaining stationary horizontally. 
     
     
         13 . The linear archery system of  claim 10  further comprising a cocking mechanism. 
     
     
         14 . The linear archery system of  claim 10  having a width of 12 inches or less. 
     
     
         15 . The linear archery system of  claim 10  further comprising a trigger assembly. 
     
     
         16 . The linear archery system of  claim 10  wherein the launching cord is wrapped three or more times around the distal pulley. 
     
     
         17 . A self-arresting propulsion system comprising:
 a) an elongated barrel member forming a cavity having an elongated barrel member proximal end and an elongated barrel member distal end, where the elongated barrel member proximal end engages a mounting stock,   b) a pair of forward spring members each having a forward spring member proximal end and a forward spring member distal end, the pair of forward spring members positioned within the cavity of the elongated barrel member wherein the distal end of the forward spring members connect to a corresponding moveable brace and the proximal ends of the forward spring members connect to a moveable pulley block,   c) a pair of rearward spring members, each having a rearward spring member proximal end and a rearward spring member distal end, the pair of rearward spring members positioned within the cavity of the elongated barrel member wherein the distal end of the rearward spring members connect to the moveable pulley block and the proximal end of the rearward spring members connects to the corresponding moveable brace,   d) a pair of forward pulleys, each forward pulley coupled to one of the forward spring member proximal ends and at least one rearward pulley, connected to the rear ward spring member distal end, and   e) a launching cord having a first end and a second end wherein the first end engages the forward pulley and second end engages the rearward pulley,   wherein the pair of forward pulleys and the rearward pulley comprise a counteracting block and tackle pulley which couples an elastic energy stored in the forward spring members and the rearward spring members when the launch cord is drawn rearward toward the stock connecting end of the barrel.   
     
     
         18 . The self-arresting propulsion system of  claim 17  further comprising a rail interiorly positioned in the barrel member. 
     
     
         19 . The self-arresting propulsion system of  claim 18  wherein the rail is configurable to vertically move while remaining stationary horizontally. 
     
     
         20 . The self-arresting propulsion system of  claim 17  further comprising a cocking mechanism. 
     
     
         21 . The self-arresting propulsion system of  claim 17  having a width of 12 inches or less. 
     
     
         22 . The self-arresting propulsion system of  claim 17  further comprising a trigger assembly. 
     
     
         23 . The self-arresting propulsion system of  claim 17  wherein the launching cord is wrapped three or more times around the distal pulley. 
     
     
         24 . A method of operating a propulsion system, the method comprising the steps of:
 a) providing a propulsion device having a) an elongated barrel member forming a cavity having an elongated barrel member proximal end and an elongated barrel member distal end, where the elongated barrel member proximal end engages a mounting stock, b) a pair of forward spring members each having a forward spring member proximal end and a forward spring member distal end, the pair of forward spring members positioned within the cavity of the elongated barrel member wherein the distal end of the forward spring members connect to a corresponding moveable brace and the proximal ends of the forward spring members connect to a moveable pulley block, c) a pair of rearward spring members, each having a rearward spring member proximal end and a rearward spring member distal end, the pair of rearward spring members positioned within the cavity of the elongated barrel member wherein the distal end of the rearward spring members connect to a moveable pulley blocks and the proximal end of the rearward spring members connect to the corresponding moveable brace, d) a pair of forward pulleys, each forward pulley coupled to one of the forward spring member proximal ends and at least one rearward pulley, connected to the rear ward spring member distal end, and e) a launching cord having a first end and a second end wherein the first end engages the forward pulley and second end engages the rearward pulley,   b) drawing the launching cord in the rearward direction to tension the launching cord and extend each of the forward spring member and rearward spring members towards each other, and   c) releasing the launching cord to provide a mutual and simultaneous transfer of energy from the tensioned springs and launching cord.   
     
     
         25 . The method of  claim 24  comprising:
 providing a linear projectile, and 
 placing the linear projectile in the barrel of the propulsion system to engage the launching cord, 
 wherein the steps of providing the linear projectile and placing the linear projectile in the barrel of the propulsion system is performed after the step of drawing the launching cord.