Patent Publication Number: US-2009235912-A1

Title: Paint ball gun driven by linear motor

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates to a paint ball gun driven by a linear motor so as to have a compact paint ball gun. 
     (2) Description of the Prior Art 
     A conventional paint ball gun is shown in  FIG. 1  and generally includes handle  11  with a barrel  12  connected thereto which is composed of a bore  121  and a chamber  122  which is located parallel to the bore  121 . The chamber  122  includes a valve  13  located close to the front end thereof and a piston  131  and a first spring  132  are installed in the chamber  122  in sequence. A link  14  and a second spring  141  are located at the rear end of the chamber  122 . An aperture  123  is defined through a wall of the bore  121  and communicates with the chamber  122 . A fixture  15  is connected to the barrel and communicates with the chamber  122  so as to be connected with the pressurized air source which provides pressurized air into the chamber  122 . A cocking handle  16  extends from the link  14  and protrudes out from the side of the chamber  133  so that when the user pulls the cocking handle  16 , the link  14  is pulled backward and a push unit  18  in the bore  121  is pulled backward. 
     When pulling the trigger  19 , the link  14  moves toward the valve  13  and the push unit  18  is moved backward. The pressurized air enters into the space  181  in the push unit  18  via the aperture  123  to push the paint ball  20  in the bore  121 . The paint ball  20  spins along the rifling grooves  182  and moves forward and goes out from the barrel  12  at high speed. 
     However, the conventional barrel has to be made to include parallel bore  121  and chamber  122 , this makes the conventional barrel to be bulky and the related parts are complicated. The size and the complicated mechanism increase the manufacturing cost. 
     The present invention intends to provide a paint ball gun which includes a linear motor located in the bore so that the barrel can be made simple and compact. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a paint ball gun and comprises a barrel connected with a handle and a drop hole and an aperture are defined through a wall of the barrel. The drop hole allows paint balls to drop into the barrel and the aperture introduces pressurized air into the barrel. A linear motor is located in the barrel and drives a retractable driving rod which is connected with a push unit located in the barrel. The push unit includes an inlet defined through a wall thereof and the inlet is moved with the push unit between a first position and a second position. The inlet is moved away from the aperture at the first position and in communication with the aperture at the second position. 
     The primary object of the present invention is to provide a paint ball gun that uses a linear motor to drive the push unit so that the barrel is slim and involves a simple structure. 
     The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial cross sectional view of a conventional paint ball gun; 
         FIG. 2  is a partial cross sectional view of the paint ball gun of the present invention, wherein the paint ball shoots out by the push unit, and 
         FIG. 3  is a partial cross sectional view of the paint ball gun of the present invention, wherein the push unit is pulled backward and another paint ball enters into the barrel. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 2 and 3 , the paint ball gun of the present invention comprises a barrel  2  connected with a handle and a trigger unit (not shown) is connected to the handle. A drop hole  21  and an aperture  22  are defined through a wall of the barrel  2 . The drop hole  21  is connected with a tube and a hopper so that paint balls  7  drop into the barrel  2  and the aperture  22  is connected with a hose  51  which is connected to a pressurized air bottle  5 . The pressurized air bottle  5  further includes a regulation device  6  which regulates the pressure of the pressurized air before being introduced into the barrel  2 . 
     A linear motor  3  is located in the barrel  2  and drives a retractable driving rod  31 . A push unit  4  is located in the barrel  2  and the driving rod  31  is connected to the push unit  4 . The push unit  4  includes a body  41 , a chamber  42  and a push end  43  which communicates with the chamber  42 . The body  41  is connected with the driving rod  31 . An inlet  421  is defined through a wall of the push unit  4 . 
     The inlet  421  is moved with the push unit  4  between a first position and a second position, wherein the inlet  421  is moved away from the aperture  22  at the first position as shown in  FIG. 2 , and communicates with the aperture  22  at the second position as shown in  FIG. 3 . Two O-rings  421  are engaged with an inner periphery of the barrel  2  and the aperture  22  is located between the two O-rings  421 . 
     As shown in  FIG. 2 , when the linear motor  3  retracts the driving rod  31  backward, the aperture  22  is sealed by the push unit  4 , and the drop hole  21  is opened so that one paint ball  7  enters into the barrel  2 . As shown in  FIG. 3 , when the user pulls the trigger unit, the linear motor  3  pushes the driving rod  31  and the push unit  4  pushes the paint ball  7  and the inlet  421  is moved to be in communication with the aperture  22  so that pressurized air enters the chamber  42  and sends the paint ball  7  out from the barrel  2  at high speed. The push unit  4  seals the drop hole  21  when the previous paint ball  7  in the barrel  2  is shot. After shooting, the push unit  4  is pulled backward, the next paint ball  7  enters into the barrel  2  for the next shoot. 
     While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.