Abstract:
An auxiliary handle of a pneumatic tool includes a gripping member, a tube, a first urging member, a pole, a second urging member and a lever. The auxiliary handle makes the user to hold the pneumatic tool with both hands. The lever is pivoted on the gripping member to be pressed to move the pole, and consequently, gas flows in the auxiliary handle are changed. As a result, the pneumatic tool will not take any action if the user only pulls a trigger of the pneumatic tool without pressing the lever.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a pneumatic tool, and more particularly to an auxiliary handle of a pneumatic tool. 
     2. Description of Related Art 
     A pneumatic tool, such as nail gun, is a tool driven by compressed gas to drive nails into an object. Typically, there are complex gas passageways in the conventional nail gun which allow compressed gas flowing through to drive the nails. The driving force of a nail gun is so strong that it would cause an accident if the operator uses it in an incorrect way. It is an important issue to provide a safe way in operating such pneumatic tools. 
     BRIEF SUMMARY OF THE INVENTION 
     In view of the above, the primary objective of the present invention is to provide an auxiliary handle of a pneumatic tool, which provides a safe way in operating the pneumatic tool. 
     In order to achieve the objective of the present invention, an auxiliary handle of a pneumatic tool, wherein the pneumatic tool has a trigger, and the auxiliary handle includes a gripping member, a tube, a first urging member, a pole, a second urging member, and a lever, wherein the gripping member is connected to the pneumatic tool, and has a room therein and an opening communicated with the room; the gripping member further has a first bore, a second bore and a third bore, each of which is communicated with the room, wherein the first bore is closed or opened when the trigger is pulled; the tube is received in the room of the gripping member to be moved between a first position and a second position, and has a first aperture and a second aperture, wherein the tube is moved to the first position by compressed gas, which enters the room via the first bore; the first urging member is received in the room of the gripping member to keep moving the tube from the first position toward the second position; the pole is received in the tube to be moved between a third position and a fourth position, wherein the pole has a front end extending out of the gripping member through the opening; the second urging member is received in the room of the gripping member to keep moving the pole from the fourth position toward the third position; the lever is pivoted on the gripping member to be moved between a normal position and a pressed position, wherein the lever has a pressing portion in touch with the front end of the pole to move the pole to the fourth position when the lever is moved to the pressed position. 
     In an embodiment, the gripping member has shaft, a lid and a plug; the first bore, the second bore, and the third bore are provided on the shaft, and the room is provided in the shaft; the lid is connected to an end of the shaft, and the opening is provided on the lid; the plug is received in the room to close an opposite end of the shaft. 
     In an embodiment, the pole is provided with a channel, and the tube further has a third aperture to be communicated with the channel. 
     Whereby, the pole closes the first aperture of the tube, and the second aperture of the tube is communicated with the first bore and the third bore when the pole is moved to the fourth position, and a direction of a gas flow between the first bore and the third bore is changed by pulling the trigger. Therefore, the process of driving nails with the pneumatic tool can only be successfully done when the operation is performed with ordered actions, which satisfies higher security requirement. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The present invention will be best understood by referring to the following detailed description of some illustrative embodiments in conjunction with the accompanying drawings, in which 
         FIG. 1  is a front view of a preferred embodiment of the present invention; 
         FIG. 2  is a right view of the preferred embodiment of the present invention; 
         FIG. 3  is a perspective view of the preferred embodiment of the present invention; 
         FIG. 4  is an exploded view of the preferred embodiment of the present invention; 
         FIG. 5  is a sectional view in the  5 - 5  line of  FIG. 3 , showing the relations between the components of the auxiliary handle while the auxiliary handle is not connected to the compressed gas supply yet; 
         FIG. 6  is a sectional view in the  6 - 6  line of  FIG. 3 , showing the relations between the components of the auxiliary handle while the auxiliary handle is not connected to the compressed gas supply yet; 
         FIG. 7  follows  FIG. 5 , showing the relations between the components of the auxiliary handle while the auxiliary handle is just connected to the compressed gas supply; 
         FIG. 8  follows  FIG. 6 , showing the relations between the components of the auxiliary handle while the auxiliary handle is just connected to the compressed gas supply; 
         FIG. 9  follows  FIG. 7 , showing the relations between the components of the auxiliary handle while the trigger is pulled; and 
         FIG. 10  follows  FIG. 8 , showing the relations between the components of the auxiliary handle while the trigger is pulled. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIG. 1  and  FIG. 2 , a pneumatic tool  100  of the preferred embodiment of the present invention is a nail gun, which includes a main body  10 , a handle  20 , a trigger  30 , a nail magazine  40  and an auxiliary handle  50 . The main body  10  has a cylinder  10   a  in an up section thereof and a muzzle  10   b  on a bottom thereof. The handle  20  is connected to the main body  10  to be held by a user. A valve stem  20   a  is on a bottom of the handle  20  to connect to a compressed gas supply hose (not shown). The trigger  30  is pivoted on the main body  10  to be pulled by a finger. The nail magazine  40  is connected to the muzzle  10   b  and the bottom of the handle  20  to feed nails. The auxiliary handle  50  is connected to the main body  10  to be held by the other hand of the user. The auxiliary handle  50  is provided with three hoses  50   a,    50   b,  and  50   c.  The hose  50   a  is connected to the cylinder  10   a,  the hose  50   b  is connected to a lid bore  10   c,  and the hose  50   c  is connected to the trigger  30 . These hoses  50   a,    50   b,  and  50   c  increase the safety in operating the nail gun  10 . 
     As shown in  FIG. 3  to  FIG. 6 , the auxiliary handle  50  has a gripping member  52 , a tube  54 , a first urging member  56 , a pole  58 , a second urging member  60 , and a lever  62 . The gripping member  52  has a shaft  521  connected to the main body  10 . The shaft  521  has a room  52   a  therein. A lid  522  is connected to a front end of the shaft  521  to close an end of the room  52   a.  The lid  522  has an opening  52   b  communicated with the room  52   a.  A plug  523  is received in the room  52   a  for sealing the room  52   a.  The shaft  521  is provided with a first bore  52   c,  a second bore  52   d  and a third bore  52   e,  which are communicated with the room  52   a.  Three valve stems  53  are connected to the bores  52   c ,  52   d,  and  52   e  respectively. The first bore  52   c  is closed when the trigger  30  is pulled. 
     The tube  54  is a round tube having an annular protrusion  541  on an outer surface. The tube  54  is provided with a plurality of first apertures  542 , a plurality of second apertures  543 , and a plurality of third apertures  544 , wherein the first apertures  542  and the second apertures  543  are on a side of the protrusion  541  and the third apertures  544  are on the other side of the protrusion  541 , and the second apertures  543  are closer to the protrusion  541  than the first apertures  542 . The tube  54  is received in the room  52   a  of the gripping member  52  for reciprocation in the room  52   a.  As shown in  FIG. 5  and  FIG. 6 , if the nail gun  100  is not connected to a compressed gas supply, the tube  54  is moved by the first urging member  56  to a second position P 2 ; and while the nail gun  100  is connected to the compressed gas supply, a part of the compressed gas enters the room  52   a  via the first bore  52   c,  which is illustrated in  FIG. 7  and  FIG. 8 . The pressure of the air in the room  52   a  will act on the protrusion  541  of the tube  54  to move the tube  54  along an opposite direction to a first position P 1 . The tube  54  will compress the first urging member  56  while the tube  54  is moved to the first position P 1 . The first urging member  56  is a spring, but not limited. A plurality of rings  55  are fitted to the tube  54  to divide the room  52   a  into two isolated chambers that may retain the compressed gas inside the inner chamber. 
     The pole  58  is received in the tube  54  for reciprocation. A plurality of rings  59  are fitted to the pole  58  for the same purpose as the rings  55 . The pole  58  is moved by the second urging member  60  to a third position P 3  when the nail gun  100  is not connected to a compressed gas supply as shown in  FIG. 5  and  FIG. 6 . As the pole  58  is at the third position P 3 , a front end  581  of the pole  58  is extended out of the gripping member  52  via the opening  52   b  of the lid  522 . On the contrary, when the pole  58  is pushed by the lever  62 , it is moved to a fourth position P 4 , as shown in  FIG. 9 . The pole  58  has a channel  582  on an inner end. The second urging member  60  is a spring, but not limited. 
     The lever  62  is an L-shaped plate with an end pivoted on the front end of the shaft  521 . The lever  62  is able to be pressed to a pressed position P 6  ( FIG. 9 ) from a normal position P 5  ( FIG. 7 ). The lever  62  has a pressing portion  621  and a gripping portion  622 . The pressing portion  621  is in touch with the front end  581  of the pole  58 , and the user may hold the gripping portion  622  to press the lever  62 . 
     If the nail gun  100  is not connected to the compressed gas supply, as shown in  FIG. 5  and  FIG. 6 , the pole  58  is moved by the second urging member  60  to the third position P 3  to move the lever  62  to the normal position P 5 , and, at the same time, the tube  54  is moved by the first urging member  56  to the second position P 2 . 
     While the nail gun  100  is connected to the compressed gas supply, as shown in  FIG. 7  and  FIG. 8 , the compressed gas enters the cylinder  10   a,  and some of the compressed gas enters the inner chamber of the room  52   a  via the hose  50   a  and the second bore  52   d,  and via the hose  50   c  and the first bore  52   c  respectively. The compressed gas via the first bore  52   c  (referring to in the arrows of dot lines in the  FIG. 7  and  FIG. 8 ) moves the tube  54  to the first position P 1 , and, at the same time, the compressed gas via the second bore  52   d  (referring to in the arrows of solid lines in the  FIG. 7  and  FIG. 8 ) flows through the first apertures  542 , the channel  582 , and the third apertures  544  in sequence, and then enters the hose  50   b  to the lid bore  10   c  to drive the nails. 
     As shown in  FIG. 9  and  FIG. 10 , when a user presses the lever  62  to the pressed position P 6 , the pressing portion  621  moves the pole  58  inwards to the fourth position P 4 . At this time, the pole  58  closes the first apertures  542  to cut off the passageway from the second bore  52   d  to the third bore  52   e.  However, the compressed gas flows from the first bore  52   c  to the third bore  52   e  through the second apertures  543  and the third apertures  544 , and finally the compressed gas flows to the lid bore  10   c.    
     When the user pulls the trigger  30 , some of the compressed gas flows back to the room  52   a,  and escapes via the first bore  52   c  and the trigger  30 . After a nail being shot, the first urging member  56  moves the tube  54  to the second position P 2  because of the escape of the compressed gas. At this time, the first apertures  542  and the second apertures  543  of the tube  54  are communicated with the channel  582  of the pole  58  again, and the passageway between the second bore  52   d  and the third bore  52   e  is opened. The compressed gas in the cylinder  10   a  flows through the lid bore  10   c  again and waits for the next shooting. 
     With the action as described above, the tube  54  is moved to the first position P 1  while the nail gun  100  connects to the compressed gas supply. If the user pulls the trigger  30  without pressing the lever  62 , the compressed gas will be exhausted, and the tube  54  will be moved back to the second position P 2 , therefore the passageway between the second bore  53   d  and the third bore  52   e  will be opened. At this time, the nails in the nail gun  100  could not be shot even if the user presses the lever  62  again. In other words, the user has to press the lever  62  before pulling the trigger  30  to shoot nails. It is a safety shooting sequence for the nail gun  100 . 
     It must be pointed out that the embodiments described above are only some preferred embodiments of the present invention. All equivalent structures which employ the concepts disclosed in this specification and the appended claims should fall within the scope of the present invention.