High-Speed Arrow-Shooting Apparatus

Abstract

An arrow-shooting apparatus includes two limbs extending backward from a barrel. An upper pulley is connected to each of the limbs. Two lower pulleys and two wheels are supported on the barrel. Each of the wheels includes a rod, a primary-string stem and a secondary-string stem. A diameter of the rod is smaller than a diameter of the corresponding wheel. Each terminal section of a primary string extends around one of the wheels and is tied to the primary-string stem of the corresponding wheel. Each of two secondary strings is tied to the secondary-string stem of one of the wheels at an end and tied to the barrel at another end, and extends around the rod of one of the wheels, one of the lower pulleys, and one of the upper pulleys.

1 . A high-speed arrow-shooting apparatus comprising:
 a barrel ( 10 );   a limb assembly ( 20 ) comprising:
 a riser ( 21 ) connected to the barrel ( 10 ); 
 two limbs ( 22 ,  23 ) each of which is connected to the riser ( 21 ) at an end and substantially extends backward in parallel to the barrel ( 10 ); 
 two upper pulleys ( 221 ,  231 ) respectively connected to the limbs ( 22 ,  23 ); 
 two bars ( 26 ,  27 ) extending from the riser ( 21 ) respectively below the limbs ( 22 ,  23 ); 
   two fins ( 31 ,  32 ) connected to the barrel ( 10 ) respectively below the bars ( 26 ,  27 );   two pivots ( 34 ) each of which is connected to a corresponding one of the bars ( 26 ,  27 ) at an end and connected to a corresponding one of the fins ( 31 ,  32 ) at another end;   two wheels ( 40 ) respectively supported on the pivots ( 34 ), wherein each of the wheels ( 40 ) comprises:
 a flat body ( 41 ); 
 a rod ( 46 ) coaxially extending from the flat body ( 41 ), wherein a diameter of the rod ( 46 ) is smaller than a diameter of the flat body ( 41 ); 
 a primary-string stem ( 44 ) extending from the flat body ( 41 ); and 
 a secondary-string stem ( 45 ) extending from the flat body ( 41 ); 
   a secondary-string pulley assembly ( 50 ) comprising
 an axle ( 51 ) transversely connected to the barrel ( 10 ); and 
 two lower pulleys ( 52 ,  53 ) supported on the axle ( 51 ) respectively below the upper pulleys ( 221 ,  231 ); 
   a primary string ( 60 ) comprising:
 two terminal sections respectively extending around the wheels ( 40 ) and tied to the primary-string stems ( 44 ) of the wheels ( 40 ); and 
 a middle section extending between the wheels ( 40 ) over the barrel ( 10 ); and 
   two secondary strings ( 71 ,  72 ) each of which is tied to the secondary-string stem ( 45 ) of a corresponding one of the wheels ( 40 ) at an end and tied to the riser ( 21 ) at another end, and extends around the rod ( 46 ) of a corresponding one of the wheels ( 40 ), a corresponding one of the lower pulleys ( 52 ,  53 ), and a corresponding one of the upper pulleys ( 221 ,  231 ).   
     
     
         2 . The high-speed arrow-shooting apparatus according to  claim 1 , wherein the riser ( 21 ) comprises two stems ( 24 ,  25 ) formed thereon, and each of the secondary strings ( 71 ,  72 ) is tied to a corresponding one of the stems ( 24 ,  25 ) of the riser ( 21 ). 
     
     
         3 . The high-speed arrow-shooting apparatus according to  claim 1 , further comprising a receptacle ( 33 ) formed between the fins ( 31 ,  32 ), wherein the receptacle ( 33 ) receives the barrel ( 10 ). 
     
     
         4 . The high-speed arrow-shooting apparatus according to  claim 1 , further comprising a shell ( 80 ) connected to the barrel ( 10 ), wherein the shell ( 80 ) covers sections of the secondary strings ( 71 ,  72 ) extending between the axle ( 51 ) and the riser ( 21 ). 
     
     
         5 . The high-speed arrow-shooting apparatus according to  claim 1 , wherein each of the wheels ( 40 ) comprises a recess ( 43 ) in a lower face of the flat body ( 41 ) and a cutout in a periphery of the flat body ( 41 ) so that the cutout is in communication with the recess ( 43 ), the primary-string stem ( 44 ) is located in the recesses ( 43 ), and the primary string ( 60 ) extends from the recess ( 43 ) through the cutout. 
     
     
         6 . The high-speed arrow-shooting apparatus according to  claim 1 , wherein each of the wheels ( 40 ) comprises a helical groove ( 42 ) for receiving a section of the primary string ( 60 ). 
     
     
         7 . The high-speed arrow-shooting apparatus according to  claim 1 , wherein the rod ( 46 ) of each of the wheels ( 40 ) comprises a helical groove ( 461 ) for receiving a section of the corresponding secondary string ( 71 ,  72 ). 
     
     
         8 . The high-speed arrow-shooting apparatus according to  claim 1 , wherein the flat body ( 41 ) of each of the wheels ( 40 ) comprises a semi-circular portion ( 411 ) and a circular portion ( 412 ). 
     
     
         9 . The high-speed arrow-shooting apparatus according to  claim 8 , wherein the flat body ( 41 ) of each of the wheels ( 40 ) further comprises a helical groove ( 42 ) in the semi-circular and circular portions ( 411 ,  412 ) to receive a section of the primary string ( 60 ).