Multi-pellet launcher with selectable choke

Abstract

A system and method for propelling pellets from a launch tube includes a retainer plug for holding the pellets inside the launch tube between the retainer plug and a compressed spring. A latch is established on the launch tube to restrain forward movement of the retainer ring in response to the bias force imposed by the compressed spring. In operation, the launch tube is propelled in a forward direction by a man-powered weapon to further compress the spring and release the latch from the retainer plug. After the initial acceleration has subsided, force from the compressed spring provides a forward propulsion of the retainer plug and the plurality of pellets from the launch tube for travel of the pellets toward an intended target. As an added feature, the launch tube can be extended to delay separation of the pellets from the tube for a so-called “choke” effect.

What is claimed is: 
     
         1 . A multi-pellet launcher which comprises:
 an elongated hollow tube formed with a lumen and having a proximal end and an open distal end;   an abutment affixed to the proximal end of the tube;   a plurality of pellets positioned inside the lumen and aligned therein to extend in a proximal direction from a location measured at a distance “L” from the distal end of the tube; and   a pellet propulsion unit mounted on the tube and configured therewith for activation thereof in response to an impulse force exerted in a distal direction on the proximal end of the launcher at a time “t o ”, to move the pellets in a distal direction through the distance “L” and to expel the pellets from the distal end of the tube at a time “t o +τ”.   
     
     
         2 . A multi-pellet launcher as recited in  claim 1  wherein the pellet propulsion unit comprises:
 a spring positioned in the lumen of the tube between the abutment and the pellets, wherein the spring has a relaxed length “x” and a spring constant “k”; and 
 an acceleration activated binary latch configured to interact with the tube to compress the spring through a distance “Δx” and to hold the pellets stationary in the tube prior to “t o ” with a response force equal to “kΔx”. 
 
     
     
         3 . A multi-pellet launcher as recited in  claim 1  wherein “L” is in a range between four and ten inches. 
     
     
         4 . A multi-pellet launcher as recited in  claim 1  wherein “τ” is in a range between 50-100 msec. 
     
     
         5 . A multi-pellet launcher as recited in  claim 1  wherein the pellets have a velocity in a range between 340-370 fps at time “t o +τ”. 
     
     
         6 . A multi-pellet launcher as recited in  claim 1  wherein the plurality of pellets includes between six and eighteen pellets. 
     
     
         7 . A multi-pellet launcher as recited in  claim 1  wherein the length “L” is provided by an extension of the tube, and the extension of the tube is selectively integrated with the tube. 
     
     
         8 . A multi-pellet launcher as recited in  claim 1  further comprising a plurality of vanes externally mounted on the tube, adjacent the proximal end thereof, to extend outwardly from the tube to provide additional aerodynamic stability for the launcher during the time interval “τ”. 
     
     
         9 . A system for launching a plurality of pellets from a multi-pellet launcher, as the launcher travels along a flight path at a flight velocity “v f ”, the launcher comprising:
 a launch tube formed with a lumen and having a proximal end and an open distal end; 
 a means for firing the launch tube onto the flight path with the flight velocity “v f ”; 
 a pellet propulsion unit mounted on the launch tube for an in-flight activation of the pellet propulsion unit at a time “t o ”, to propel the plurality of pellets in a distal direction at a propulsion velocity “v p ” through the lumen of the launch tube; and 
 a launch tube extension having a length “L”, wherein the launch tube extension is integrated with the launch tube to continue movement of the plurality of propelled pellets inside the launch tube, through the length “L”, for an additional time interval “τ” immediately after the launch activation time “t o ”, to attain a muzzle velocity “v m ” for the pellets, where v m =v f +v p . 
 
     
     
         10 . A system as recited in  claim 9  wherein an abutment is affixed to the proximal end of the tube and the pellet propulsion unit comprises:
 a spring positioned in the lumen of the tube between the abutment and the pellets, wherein the spring has a relaxed length “x” and a spring constant “k”; and 
 an acceleration activated binary latch configured to interact with the tube to compress the spring through a distance “Δx” and to hold the pellets stationary in the tube prior to “t o ” with a response force equal to “kΔx”. 
 
     
     
         11 . A system as recited in  claim 10  wherein the firing means exerts an impulse force on the launch tube at time “t o ” to accelerate the launch tube to flight velocity “v f ”, and to activate the pellet propulsion unit. 
     
     
         12 . A system as recited in  claim 9  wherein “L” is in a range between four and ten inches. 
     
     
         13 . A system as recited in  claim 9  wherein “τ” is in a range between 50-100 msec. 
     
     
         14 . A system as recited in  claim 9  wherein the muzzle velocity “v m ” is in a range between 340-370 fps. 
     
     
         15 . A system as recited in  claim 9  further comprising a plurality of vanes externally mounted on the tube, adjacent the proximal end thereof, to extend outwardly from the tube to provide additional aerodynamic stability for the launcher during the time interval “τ”. 
     
     
         16 . A system as recited in  claim 9  wherein the means for firing the launch tube is selected from a group comprising a conventional bow, a compound bow, a crossbow, and an air gun. 
     
     
         17 . A method for assembling a multi-pellet launcher which comprises the steps of:
 providing a launch tube formed with a lumen and having a proximal end and an open distal end, with an abutment affixed to the proximal end of the tube;   selecting a spring having a relaxed length “x” and a spring constant “k”;   positioning the spring inside the lumen of the tube against the abutment at the proximal end thereof;   deciding upon an “n” number of pellets;   aligning the “n” number of pellets in the lumen of the launch tube, distal to the spring; and   configuring an acceleration-activated binary latch with the launch tube at a distance “L” from the distal end of the launch tube, to hold the pellets between the latch and the spring, and to compress the spring through a distance “Δx” to generate a spring force equal to “kΔx” for propelling the pellets through the distance “L” within a time interval “τ”, in response to an activation of the binary latch at a time “t o ”.   
     
     
         18 . A method as recited in  claim 17  further comprising the steps of:
 identifying an operational muzzle velocity “v m ” for the pellets, wherein “v m ” equals the sum of a flight velocity “v f ” of the launch tube and a propulsion velocity “v p ” for the pellets during the time interval “τ” inside the lumen of the launch tube (v m =v f +v p ); and 
 selecting values for the variables “x”, “k”, “n” and “L” to achieve the required “v p ”. 
 
     
     
         19 . A method as recited in  claim 18  wherein “L” is in a range between four and ten inches, wherein “τ” is in a range between 50-100 msec, and wherein the muzzle velocity “v m ,” is in a range between 340-370 fps. 
     
     
         20 . A method as recited in  claim 18  wherein “v f ” results from the application of an impulse force on the launch tube at the time “t o ”.