Patent Publication Number: US-9835404-B2

Title: Pneumatic firing device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a pneumatic firing device, particularly to one that fires pellets by airflows produced from the operation of a pressure release channel and that is especially suitable for application to Ball Bearing guns, also known as BB guns. 
     2. Description of the Related Art 
     Nowadays people like to play war games like paintball and survival games with air gun including BB guns that are highly intense for stress relief, especially those living in cities. 
     Both BB guns and paintball guns fire the pellets by pressured air, mechanically or electronically. A mechanical firing has a trigger controlling the air passage within the device to fire, each pulled for one shot, but a user of mechanical guns cannot pull the trigger fast enough for rapid fires. An electronic firing has a trigger controlling the operation of a solenoid valve in the device to fire, and it is able to conduct rapid fire. 
     Such design of air guns has pressured air as the driving force for firing with adjustments by the structure. In U.S. Pat. No. 5,727,538, No. 6,516,791, and U.S. Pat. No. 6,532,949, different projectile firing devices and pneumatic operations are disclosed; however, when combining the electronic devices with the pneumatically driven operations, the mechanic devices would encounter more complexities for operations which then become potential problems. Also, the costs for manufacturing would increase as well. 
     U.S. Pat. No. 6,601,780 and U.S. Application Publication No. 2005/005924 disclosed a pneumatic operation for firing a paintball gun which ensures more safety and less malfunctions with a faster firing speed. In both cases a delivery tube has to engage a return spring for the delivery tube to displace back to its original position. As the standard of firing speed gets higher, the return spring would encounter elastic fatigue after frequent use and displacement of the delivery tube would be slowed down; on the other hand, the pressure pushing the delivery tube to fire is not affected at all. Consequently, the operation would be unsmooth due to the incoordination between firing and returning. 
     Therefore, it is desirable to overcome the defect disclosed and further find improvements for such devices. 
     SUMMARY OF THE INVENTION 
     A primary object of the present invention is to provide a pneumatic firing device that has a smooth operation of firing with less malfunctions and faster firing speed. 
     Another object of the present invention is to provide a pneumatic firing device that has simple structure for easy assembly and low prime cost. 
     Yet another object of the present invention is to provide a pneumatic firing device that is able to adjust the firing speed. 
     In order to achieve the objects above, the present invention comprises a hollow cylinder including a first opening arranged at an end thereof, a second opening arranged at the other end thereof, and a first entry hole arranged at the bottom thereof for connecting an external air supply tube; 
     a rear section having a front end engaging the second opening of the cylinder, a first hole arranged at a front part thereof, a screw hole arranged at a rear part thereof connecting to the first hole, and a pressure release vent arranged at the bottom thereof connecting to the first hole; the pressure release vent further linking to a pressure release room from a bottom thereof; 
     a solenoid valve connecting to the pressure release room from under and having a movable plunger as a gate for opening and closing the pressure release room; the movable plunger having a first outlet arranged at a hollow lower part thereof, and a second outlet arranged at a bottom of the solenoid valve for the air released from the pressure release room to be discharged therefrom via the first outlet and the second outlet; 
     an adjusting element engaging in the first hole of the rear section with a tail section arranged as a threaded section for screwing the screw hole and a front part including a pressure release channel; said pressure release channel having a through hole at a front end thereof and connecting the pressure release vent at a rear end thereof; 
     a piston disposed in the second opening with an engaging hole arranged at a front thereof and a connecting hollow arranged at a rear thereof for connection to the engaging hole; the piston further forming a first gap between which and the adjusting element when moving forward; 
     an airflow guiding element engaging a front of the cylinder and having a tube body with a first diameter at a front section thereof, a ring element with a second diameter at a rear thereof, and a guiding passage connecting the tube body and the ring element; the second diameter being loner than the first diameter; the tube body further having at least one first guiding hole arranged thereon at a side near the ring element, forming a first passage connecting the cylinder and the tube body, and at least one second guiding hole arranged thereon at a side far from the ring element; at least one O-ring being arranged on the tube body between the first guiding hole and the second guiding hole, and an axial hole being arranged within the tube body between the first guiding hole and the second guiding hole, forming a second passage connecting the second guiding hole; the ring element further having a third guiding hole arranged on an inner surface thereof which extends to a front thereof; 
     a moving rod having a tail end engaging the engaging hole of the piston, a second entry hole linking up the connecting hollow, and a front end stretching out the cylinder into the airflow guiding element and including a valve with a diameter of a length between the first and second diameter; said valve further including a stick with a front of which stretching through the axial hole, forming a blocking section to control the blocking of the axial hole upon being driven by the moving rod in operation; when the moving rod moving backward and the valve leaving the guiding passage, a second gap being formed in between, and when the moving rod moving forward, a third gap being formed between the blocking section and the axial hole; 
     a front section engaging the airflow guiding element and having a second hole and a fourth guiding hole connecting the third guiding hole correspondingly; said fourth guiding hole further extending a third passage to the front of the second hole; 
     a delivery tube including a first tube and a second tube connecting with each other; the diameter of the first tube being longer than the one of the second tube for engaging the tube body, and a first O-ring being arranged on the surface of the first tube corresponding to the second hole for the delivery tube to displace in the second hole; the first tube further connecting the second passage to form a passage for firing, and when the delivery tube returning to the original position, a fourth gap being formed between the first tube and the first guiding hole and a fifth gap being formed between the second tube and the second hole; 
     a positioning element screwed to a front screw hole of the front section and having an abutting ring to block and close the fifth gap for preventing air leakage therefrom without affecting displacements of the delivery tube; 
     Whereby the solenoid valve holds control of the operation of the pressure release channel to change the pressure difference between a first chamber arranged at a front side of the piston and a second chamber arranged at a rear side of the piston, then the pressured air would flow into the first passage via the first guiding hole of the airflow guiding element, displacing the delivery tube and driving a pellet therein to move forward, and then flow into the second passage via the second guiding hole to fire the pellet from the passage for firing with strong airflow; meanwhile, partial pressured air would enter the fifth gap via the third passage and gradually displace the delivery tube back into an original position by a pushing force. 
     In addition, in a preferred embodiment, the present invention further includes a first spring disposed between the adjusting element and the connecting hollow for providing an ejection force for the piston to move forward; and the adjusting element further has a non-circular socket arranged at a tail end thereof for a wrench to adjust the position of the adjusting element from the screw hole of the rear section. 
     A plurality of blades is arranged at the middle section of the stick and the blocking section has inclined surfaces extending to both ends. The positioning element is a short bolt and a second O-ring is arranged between the abutting ring and the positioning element for blocking the air in the fifth gap to prevent from leakage and for the second tube of the delivery tube to displace through. 
     The front section further has a first concave end engaging a first convex end of the airflow guiding element, and the first convex end has a third O-ring mounted thereon in order to seal the engaging ends. The rear section further has a second convex end with a fourth O-ring mounted thereon to seal the engaging rear section and second opening of the cylinder. 
     The delivery tube is further engaging a loading device including a loading entry for the supply of pellets and a barrel being arranged perpendicularly to the loading entry and connecting the delivery tube; and the device and the loading device are disposed inside a housing, and the housing further includes a grip arranged corresponding to the solenoid valve and the external air supply tube; the grip further has an air inlet connecting the external air supply tube. 
     With features disclosed above, the present invention changes the pressure difference between the first chamber and the second chamber, controls the operation of the pressure release channel to push forward the delivery tube with pressured air, sending a pellet therein into the passage for firing, and then fires the pellet from the second passage with strong airflow. Such structure enables a smooth airflow for operation, less malfunctions, and faster firing speed. The adjusting element can also adjust the firing speed by displacement to control the operation of the piston. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of the present invention; 
         FIG. 1A  is an enlarged view of major components of the present invention; 
         FIG. 2  is a perspective view of the present invention; 
         FIG. 3  is a sectional view of the present invention illustrating a movable plunger thereof in the original closing status; 
         FIG. 3A  is an enlarged view of area  3 A in  FIG. 3 ; 
         FIG. 3B  is an enlarged view of area  3 B in  FIG. 3 ; 
         FIG. 3C  is an enlarged view of area  3 C in  FIG. 3B ; 
         FIG. 4  is a sectional view of the present invention illustrating the movable plunger and a valve thereof in an opening status; 
         FIG. 4A  is an enlarged view of area  4 A in  FIG. 4 ; 
         FIG. 4B  is an enlarged view of area  4 B in  FIG. 4 ; 
         FIG. 4C  is an enlarged view of area  4 C in  FIG. 4B ; 
         FIG. 5  is a sectional view of the present invention illustrating airflow entering a second hole thereof from a first guiding hole thereof; 
         FIG. 5A  is an enlarged view of area  5 A in  FIG. 5 ; 
         FIG. 5B  is an enlarged view of area  5 B in  FIG. 5 ; 
         FIG. 6  is a sectional view of the present invention illustrating airflow entering a passage for firing thereof from a second guiding hole thereof; 
         FIG. 6A  is an enlarged view of area  6 A in  FIG. 6 ; 
         FIG. 6B  is an enlarged view of area  6 B in  FIG. 6 ; 
         FIG. 7  is a sectional view of the present invention illustrating the movable plunger in a closing status; 
         FIG. 7A  is an enlarged view of area  7 A in  FIG. 7 ; 
         FIG. 7B  is an enlarged view of area  7 B in  FIG. 7 ; 
         FIG. 8  is a sectional view of the present invention illustrating the movable plunger closing, a delivery tube thereof returning back, and airflow in the second hole being discharged from a blocking section thereof via the first guiding hole; 
         FIG. 8A  is an enlarged view of area  8 A in  FIG. 8 ; 
         FIG. 8B  is an enlarged view of area  8 B in  FIG. 8 ; and 
         FIG. 9  is a practical application view of the present invention applied to a Ball Bearing gun. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment is illustrated in  FIGS. 1-9 , among which  FIG. 9  is a practical application view of the present invention applied to a Ball Bearing gun (BB gun). Referring to  FIGS. 1-3C , the present invention, a pneumatic firing device  90 , includes a hollow cylinder  10 , a rear section  20 , a solenoid valve  25 , an adjusting element  30 , a piston  40 , an airflow guiding element  50 , a moving rod  60 , a front section  70 , a delivery tube  80 , and a positioning element  73 . 
     The hollow cylinder  10  includes a first opening  11  arranged at an end thereof, a second opening  12  arranged at the other end thereof, and a first entry hole  13  arranged at the bottom thereof for connecting an external air supply tube  14 . 
     The rear section  20  has a front end engaging the second opening  12 , a first hole  21  arranged at a front part thereof, a screw hole  22  arranged at a rear part thereof connecting to the first hole  21 , and a pressure release vent  23  arranged at the bottom thereof connecting to the first hole  21 . The pressure release vent  23  further links to a pressure release room  24  from a bottom thereof. In this embodiment, the rear section  20  further has a second convex end  26  with a fourth O-ring  27  mounted thereon to seal the engaging rear section  20  and second opening  12  of the cylinder  10 . 
     The solenoid valve  25  connects to the pressure release room  24  from under by at least one screw (not shown) and has a movable plunger  251  as a gate for opening and closing the pressure release room  24 . The movable plunger  251  has a first outlet  253  arranged on the periphery of a hollow lower part with a second spring  255  disposed therein, and a second outlet  254  arranged at a bottom of the solenoid valve  25  for the air released from the pressure release room  24  to be discharged therefrom via the first outlet  253  and the second outlet  254 . In this embodiment, the movable plunger  251  is a movable iron core at the center of the solenoid valve  25 , having a rubber piece  2511  at the front end thereof, so that when a surrounding coil  252  is activated by electric currents, the movable plunger  251  is able to stretch out and return to control the operation of the pressure release vent  23 . 
     The adjusting element  30  engages in the first hole  21  of the rear section  20  with a tail section arranged as a threaded section  31  for screwing the screw hole  22  and a front part including a pressure release channel  32 . The pressure release channel  32  further has a through hole  35  at a front end thereof and connects the pressure release vent  23  at a rear end thereof. In this embodiment, the adjusting element  30  has a non-circular socket  33  arranged at a tail end thereof for a wrench  34  to adjust the displacement of the adjusting element  30  in the first hole  21  from the screw hole  22  of the rear section. For instance, the non-circular socket  33  is a hexagonal socket, and the wrench  34  is an L wrench. 
     The piston  40  is disposed in the second opening  12  with an engaging hole  41  arranged at a front thereof and a connecting hollow  42  arranged at a rear thereof for connection to the engaging hole  41 . The piston  40  further has a fourth O-ring  44  arranged on the periphery thereof. In a preferred embodiment, the present invention includes a first spring  43  disposed between the adjusting element  30  and the connecting hollow  42  for providing an ejection force for the piston  40  to move forward; the piston  40  can also be driven by airflows instead of the first spring  43  in other embodiments. 
     The airflow guiding element  50  engages a front of the cylinder  10  and has a tube body  51  with a first diameter  511  at a front section thereof, a ring element  52  with a second diameter  521  at a rear thereof, and a guiding passage  522  connecting the tube body  51  and the ring element  52 . The second diameter  521  is longer than the first diameter  511 , and the tube body  51  further has at least one first guiding hole  512  arranged thereon at a side near the ring element  52 , forming a first passage  53  connecting the cylinder  10 , and at least one second guiding hole  513  arranged thereon at a side far from the ring element  52 ; at least two O-rings  514  are further arranged on the tube body  51 , at least one of which is arranged between the first guiding hole  512  and the second guiding hole  513 . Additionally, an axial hole  515  is arranged within the tube body  51  between the first guiding hole  512  and the second guiding hole  513  as shown in  FIGS. 3C and 4C , forming a second passage  54  connecting the second guiding hole  513 ; the second passage  54  is also the major passage for firing. The ring element  52  further has a third guiding hole  523  arranged on an inner surface thereof, extending toward the tube body  51 . 
     The moving rod  60  has a tail end  61  engaging the engaging hole  41  of the piston  40 , a second entry hole  62  linking up the connecting hollow  42 , and a front end stretching out the cylinder  10  into the airflow guiding element  50  and including a valve  63  with a diameter of a length between the first and second diameter  511 ,  521 . The valve  63  further includes a stick  64  with a front of which stretching through the axial hole  515 , forming a blocking section  65  to control the blocking of the axial hole  515  upon being driven by the moving rod  60  in operation. The blocking section  65  has inclined surfaces extending to both ends so that when the moving rod  60  is moving backward and the valve  63  is leaving the guiding passage  522 , a second gap S 2  is formed in between as shown in  FIG. 4C , and when the moving rod  60  is moving forward, a third gap S 3  is formed between the blocking section  65  and the axial hole  515  as shown in  FIG. 3C . 
     With reference to  FIGS. 1A and 3C , in this embodiment, a plurality of blades  641  is arranged at the middle section of the stick  64  for a stably axial displacement of which within the airflow guiding element  50 . The front section  70  engages the front of the airflow guiding element  50 , having a second hole  71  and a fourth guiding hole  76  connecting the third guiding hole  523  correspondingly; the fourth guiding hole  76  further extends and forms a third passage  72  to the front of the second hole  71 . Furthermore, the front section  70  has a first concave end  75  engaging a first convex end  55  of the airflow guiding element  50 , and the first convex end  55  has a third O-ring  56  mounted thereon in order to seal the engaging ends.  FIG. 1A  illustrated engagement of the front section  70  and the airflow guiding element  50  with at least one engaging section  77  arranged at the rear thereof to be screwed through by a bolt  78  for fixing; the at least one engaging section  77  includes a through hole  771  with a longer diameter than a head  782  of the bolt  78  and a positioning groove  772  for a threaded rod  781  of the bolt  78  to pass through and abutting on the head  782 . 
     The delivery tube  80  includes a first tube  81  and a second tube  82  connecting with each other. The diameter of the first tube  81  is longer than the one of the second tube  82  for engaging the tube body  51 , and a first O-ring  83  is arranged on the surface of the first tube  81  corresponding to the second hole  71  for the delivery tube  80  to displace in the second hole  71 . The first tube  81  further connects the second passage  54  to form a passage for firing  84 , and when the delivery tube  80  returns to the original position, a fourth gap S 4  is formed between the first tube  81  and the first guiding hole  512  and a fifth gap S 5  formed between the second tube  82  and the second hole  71 . 
     The positioning element  73  is screwed to a front screw hole  74  of the front section  70 . In the embodiment, the positioning element  73  is a short bolt and has an abutting ring  731  and a second O-ring  732  arranged between the abutting ring  731  and the positioning element  73  as shown in  FIGS. 1 and 3 , so as to block and close the fifth gap S 5  to prevent air leakage therefrom without affecting displacements of the second tube  82  of the delivery tube  80 . 
     Further referring to  FIG. 9 , the present invention is applied to a BB gun. In the application, the delivery tube  80  is engaging a loading device  100  including a loading entry  101  for the supply of airsoft pellets  102  and a barrel  103  being arranged perpendicularly to the loading entry  101  and connecting the delivery tube  80  so that when the passage for firing  84  sends out strong airflow, the pullets—airsoft pellets— 102  is fired. Additionally, the pneumatic firing device  90  and the loading device  100  are disposed inside a housing  200 , and the housing  200  further includes a grip  201  arranged corresponding to the solenoid valve  25  and the external air supply tube  14  for pressured air to enter via an air inlet  202  connecting to the external air supply tube  14 . The pressured air may come from a gas cylinder or other pneumatic devices. Also, the grip  201  includes a trigger  203  for pulling and the loading device  100  can be engaged a magazine  204 , as designed for application to BB guns. 
     A main feature of the present invention is that the fifth gap S 5  is formed between the second tube  82  of the delivery tube  80  and the second hole  71 , and the fifth gap S 5  is connecting the third passage  72  of the front section  70 , so that the present invention is able to complement the defect of a return spring and to ensure a smooth operation. The operations and applications of the pneumatic firing device  90  are described as following with referred drawings. 
     Referring to  FIGS. 3-3C , the movable plunger  251  of the solenoid valve  25  is originally closing and blocking the pressure release vent  23  of the pressure release room  24 . In this embodiment, the first spring  43  provides a pushing force for the piston  40  to move forward, therefore forming a first gap S 1  between the piston  40  and the adjusting element  30 , so that the pressure air A entering a first chamber  10   a  arranged at a front side of the piston  40  via the first entry hole  13  is able to rapidly enter a second chamber  10   b  arranged at a rear side of the piston  40  via the second entry hole  62  through the first gap S 1 . Also, the pressured air A can enter the second chamber  10   b  via the through hole  35  at the front of the adjusting element  30 . In other words, even if the piston  40  moves backwards and block the first gap S 1 , the pressure air A will not be blocked for flowing into the second chamber  10   b . The space of the first gap S 1  is decided by the displacement of the adjusting element  30  in the first hole  21  and is controlled thereby during operation. Then, when the pressure release vent  23  is blocked by the movable plunger  251 , the pressured air A is blocked as well; the piston  40  then moves forward due to the pressure difference and abuts the valve  63  of the moving rod  60  to the guiding passage  522 , blocking the pressured air A in the first chamber  10   a  and producing a pushing force. The delivery tube  80  thereby returns to original status. 
     Referring to  FIGS. 4-4C , the movable plunger  251  opens the pressure release vent  23  by the trigger  203 , and the pressured air A enters into the pressure release room  24  via the pressure release channel  32 , then flow through the first outlet  253  of the movable plunger  251  and be discharged from the second outlet  254 . The pressure force in the first chamber  10   a  is therefore stronger than the force of the first spring  43  and the pushing force, thereby detaching the valve  63  from the guiding passage  522  and forming a second gap S 2 , so that the pressured air A in the first chamber  10   a  would flow out from the guiding passage  522  into the first passage  53  via the first guiding hole  512  and the fourth gap S 4  and go to the second tube  82  of the delivery tube  80 . 
       FIGS. 5-5B  illustrated the operation process of the pressured air A moving the delivery tube  80  forward. The first tube  81  of the delivery tube  80  detaches from the first guiding hole  512  but does not detach from the second guiding hole  513  yet; meanwhile the delivery tube  80  sends the airsoft pellet  102  into the barrel  103  from the loading entry  101 . 
     Further referring to  FIGS. 6-6B , when the first tube  81  of the delivery tube  80  leaving the second guiding hole  513 , the pressured air A flows into the second passage  54  via the first passage  53  and the second guiding hole  513 , then fires the airsoft pellet  102  via the passage for firing  84  with strong airflow. 
     Then, referring to  FIGS. 7-7B , the movable plunger  251  returns to block the pressure release channel  32  again and the air pressure in the second chamber  10   b  has changed, thus moving the piston  40  forward. Meanwhile, partial pressured air A would enter into the fifth gap S 5  and send t back he delivery tube  80  to the original position. Then the piston  40  moves forward again, back to the original closing status as shown in  FIGS. 8-8B . The valve  63  abuts to the guiding passage  522  again and blocks the second gap S 2  to stop the pressured air A from flowing out; and the third gap S 3  is opened to discharge the rest pressured air A. Then the device returns back to the original status as shown in  FIG. 3 —the delivery tube  80  is ejected and pushed by the pushing force from the pressured air A in the fifth gap S 5  and the first gap S 1  is unblocked. 
     With aforesaid structures and measures, the present invention has A change of air pressure to operate the pneumatic device  90 . It pushed the airsoft pellet  102  in the delivery tube with weak airflows, and then fires with a strong one. Such structure has effects described as following. 
     1. With the solenoid valve  25  controlling the operation of the pressure release channel  32  to change the pressure difference between the first chamber  10   a  and the second chamber  10   b , the pressured air A flows into the first passage  53  via the first guiding hole  512  of the airflow guiding element  50 , displacing the delivery tube  80  forward and driving a airsoft pellet  102  therein to move forward, and then flows into the second passage  54  via the second guiding hole  513  to fire the airsoft pellet  102  from the passage for firing  84  with strong airflow. The air flows smoothly during the operation, thus increasing the firing speed. 
     2. With such simple structure, the present invention is easily assembled and therefore less malfunctioned. In addition, the pneumatic firing device  90  is modular for various applications to different devices. 
     3. The first passage  53  is a minor passage for airflow to gather and enter the second passage  54  which is the major passage for the operation. The airflow is therefore able to strongly fire the airsoft pellet  102  during the operation. Consequently the present invention is able to smoothly operate the firing with low pressure, ensuring more safety and less cost for manufacturing. 
     4. The displacement of the adjusting element  30  in the first hole  21  of the rear section  20  is able to control the operation of the piston  40 , thus enabling the device to adjust the firing speed. 
     5. The third passage  72  enable partial pressured air A to enter into the fifth gap S 5  to produce a force to push back the delivery tube  80  to its original position, therefore complementing the defect of a return spring in the prior art. 
     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.