Patent Publication Number: US-2007095409-A1

Title: Pneumatic wrench

Description:
BACKGROUND OF THE INVENTION  
      1. Fields of the Invention  
      The invention relates to a pneumatic wrench, and more particularly, to a pneumatic wrench having a simple assembly structure and an excellent application value.  
      2. Description of the Related Art  
      Most of pneumatic wrenches of the same art include a main body, a cylinder, an arresting device, a bearing, an air control element, a sealing hood and an adjusting element. Different pneumatic wrenches could have variation in design; however, the total amount of their components doesn&#39;t have much difference.  
      It is well-known that the fabrication and assembly of one product could be more cost-intensive and labor-intensive when this product has more components. Meanwhile, the problem of adaptability among different components easily arises when more components are employed. Besides, more defects could be created as well, thereby affecting the product quality.  
     SUMMARY OF THE INVENTION  
      It is a primary object of the invention is to provide a pneumatic wrench that can be fabricated with lower cost, for example, by combining two or more components in a single one for achieving the economic benefit and enhancing the product quality.  
      In order to achieve the above-mentioned object, the air control element and the sealing hood of the prior art are combined to be a new component that is named “air control hood”. The air control hood is screwed to a rear side of the cylinder receptacle of the main body, thereby fixing a cylinder, an arresting device and a bearing in place and sealing a cylinder receptacle of a main body. Meanwhile, the air control hood further includes an air intake channel and two corresponding air guide channels that work in cooperation with an adjusting knob having air control channels for controlling the path of and the rate of the air flow in admission into or exhaust out of the cylinder, thereby ensuring an effective control of the rotational direction and torque of an action end of the main body. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accomplishment of this and other objects of the invention will become apparent from the following description and its accompanying drawings of which:  
       FIG. 1  is a perspective exploded view of a preferred embodiment of the invention;  
       FIG. 2  is a perspective view of the preferred embodiment of the invention;  
       FIG. 3  is a cutaway view of the partial assembly of the preferred embodiment of the invention;  
       FIG. 4  is a side view of an adjusting knob of the invention;  
       FIG. 5  is a cutaway view taken along the line A-A of  FIG. 4 ;  
       FIG. 6  is a side view of an air control hood of the invention;  
       FIG. 7  is a cutaway view taken along the line B-B of  FIG. 6 ;  
       FIG. 8  is a front view of the air control hood of the invention;  
       FIG. 9  is a cutaway view taken along the line C-C of  FIG. 8 ; and  
       FIG. 10  is a rear view of the air control hood of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring to  FIGS. 1 through 3 , a preferred embodiment of the invention includes:  
      a main body  10  having a handle  11 , an action end  12 , an air inlet  13 , a cylinder receptacle  14  and a start switch  15 ;  
      a cylinder  20  having a cylinder chamber  21 ;  
      an arresting device  30  disposed within the cylinder chamber  21  of the cylinder  20  corresponding to fan blades (not shown), the arresting device  30  having an output shaft  31  extending in axial direction for imparting rotational movement to the action end  12  of the main body  10 ;  
      a bearing  40  mounting on a second output shaft opposite to the output shaft of the arresting device;  
      an air control hood  50  attached to the cylinder  20  by screwing elements  22  and placed into the cylinder receptacle  14  of the main body  10 , the air control hood  50  being attached by long screws to the rear side of the cylinder receptacle  14  of the main body  10 , thereby fixing the cylinder  20 , the arresting device  30  and the bearing  40  in place and sealing the cylinder receptacle  14  of the main body  10 , the air control hood  50  further having an air intake channel  52  and two corresponding air guide channels  53 , a receiving groove  55  being formed at a rear end of the air control hood  50 ;  
      an adjusting knob  60  having an air control channel  61 , the adjusting knob  60  being positioned within the receiving groove  55  of the air control hood  50  by use of set screws  62  and restricting recesses  63  so that a certain operation mode can be activated.  
      As shown in  FIGS. 3 through 10 , the control of air intake is performed in such a way that the air flows in the direction shown by arrow through the air inlet  13  of the main body  10  into an air chamber  16  of the handle  11  of the main body  10 . Then, it passes through prearranged channels into the air intake channel  52  under the air control hood  50 . Thereafter, the air is guided into the air control channel  61  of the adjusting knob  60 . In this way, when the adjusting knob  60  is turned such that the air control channel  61  is directed to the first air guide channel  53  or the second air guide channel  54  of the air control hood  50 , the air can pass from the desired channel through the air control hood  50  into the cylinder chamber  21  of the cylinder  20 . As shown in  FIG. 10 , the upper blades of the arresting device  30  are exposed to force and therefore driven by wind force in positive or reverse rotation since the first air guide channel  53  and the second air guide channel  54  are positioned at opposing sides.  
      Particularly, when the first air guide channel  53  is employed for air intake, the second air guide channel  54  is automatically converted for air exhaust. Accordingly, the air escaped from the cylinder chamber  21  will be delivered to a second air exhaust channel  56  located slightly lower than the second air guide channel  54 . It is because the second air guide channel  54  and the air control channel  61  are blocked by the adjusting knob  60 . In addition, a second guide groove  64  is employed to guide the air to a reserved gap  17  between the cylinder  20  and the cylinder receptacle  14 . Thereafter, the air reaches an empty chamber  18  and an air outlet  19  within the handle  11  of the main body  10  for air escape. On the contrary, when the second air guide channel  54  is employed for air intake, the first air guide channel  53  will be automatically converted for air exhaust. Accordingly, the air will be escaped along a route created by a first air exhaust channel  57 , a first guide groove  65 , the gap  17 , the empty chamber  18  and the air outlet  19 .  
      As previously described, the adjusting knob  60  is employed to control the admission and exhaust of air for imparting positive or reverse rotational motion to the arresting device  30 . Furthermore, a step-by-step control of the gap between the air control channel  61  and the first air guide channel  53  can be achieved when the arresting device  30  is rotated in positive direction for performing the tightening action of the action end  12 . In this way, the air flow rate into the arresting device  30  can be effectively controlled. In brief, this ensures a reliable control over the torsion output of the action end  12 . Accordingly, the tightening force on the screw elements (not shown) can be optimally applied without the problem of excessive or insufficient force.  
      Many changes and modifications in the above-described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claims.