There are stationary machine, such as turning machine or milling machine and the machine carryable by a person, like air tools which are our main product. We call this carryable machine as "Portable Tool". Portable tools are separated into Electric Power Tool, Air Tool, Hydraulic Tool, Engine Tool and etc. by its power source.

Air tool is formally called as "Aerodynamic Tool" or "Pneumatic Tool" (Pneumatic Tool) and widely used next to electric power tool.

Human being has only small power as power source and we have only 1/10 horse-power in a short time./However, by using power tool, we can get very big horse-power according to the capacity of tool to finish the job.

The air tool is small size, light weight and high power and its strong point as portable tool has advantage conspicuously. So, air tool has existence value as the portable tool for professional use. It is widely used for production line of automobile or electric equipment, ship-building, machine manufacturing and automobile repairing.

The feature of air tool comparing with electric power tool are,

• Compact size and light weight.
• Durable for over-loading. Usually, portable tool is used with over-loading and the motor is overheated if electric power tool.But air tool doesn't have such problem.
• Easy to get high speed rotation.
• Better water resistance.
• Air tool has no danger of flash ignition, explosion and electric-shock.Electric spark may cause the danger of big accident in the explosive atmosphere, such as mine, gas station and auto-repair garage.The electric power tool also has danger of electric-shock.Electric-shock has not only its danger and also has incidental accident, such as the worker throw out or fall down the tool when electric-shock.
• It is suitable for the driving of impact tools as easy to get high accelerated rotation.
• Easy to control the speed.
• Easy handling and repairing.

The strong points of air tool are connected with close relation between air and human being and it doesn't need using cost and freely selectable and is able to accumulate big energy by compression. And this very important point that we don't feel the heaviness.

On the other hand, air tool has disadvantages. As the first, driving cost may be high. Because it must need to generate the compressed air by operating air compressor using generating machine of some kind. Also the efficiency of air motor isn't so good. Therefore, driving cost of air tool is higher as compared with electric power tool. Another disadvantage is exhaust air. During the cold season, the exhaust air is cold for worker and its exhaust noise is uncomfortable for worker too.

Of course, impact wrench is our main product and also the products which has most important and strong point in the air tool. The knowledge of impact wrench is the most important in our products too. Impact wrench uses "Impact Force" which other general machines don't use so much. So, its working feature, skillful use, the matter during use and etc. may not be easy to understand always.

Impact Force
The force to the object is separated into static force and impact force by its speed. When the object is on the desk, the force to the desk is one of typical static force. The batting of baseball or hitting a shot of golf is the example applying the impact force.General nature of static force is balancing of action and counteraction. It doesn't have so much loss in the force transfer and we can say it is efficiency force. However, if the foothold isn't firm we can't get big force.
When you fasten the screw by hand using spanner, this is the application of static force and human being must make the foothold firmed otherwise you can't get the force. Also for the screw, fastened object must be fixed, otherwise the object moves before the screw is fastened.
But given force transfers to the opponent object without loss and size of given force is easily measured. The general nature of impact force is to be able to use very strong force even instantaneously.
And it doesn't create so much reaction force by the inertial action. Accordingly, even if the foothold isn't so firm, we can create big force.

Fastening the screw with applying impact force is same as beating the spanner with a hammer. (Showing as per illustration at left.) In this case, the action is quite different from screw fastening by static force as mentioned above. In other word, impact force has less counteraction and we can fasten with very high torque even the foothold or opponent object isn't fixed firmly.We summarize the good and bad point of impact force. Good point is,

• It can generate very strong force even instantaneously.
• Counteraction is small.
• Able to get the force according to the situation.In other word, when hit hard object you can get big force and when hit soft object you can't get so much force.

Bad point seems,

• It breaks down easily.
• Not suitable to work efficiency as action time is short.

We now mention about the structure of "Air Motor". Air Motor lets rotor rotate in high speed instantaneously by strong force from the rotor blades which have the compressed air on them.

Please refer drawing of "Operation of Air Motor" as below. It operates with a cycle of air-supply and expansion. At the beginning, air-supply comes into small gap between cylinder, rotor and rotor blade through air channel, then air is expanded according to the rotation of rotor and major amount is exhausted from 1st exhaust hole through upper exhaust hole. Additionally, balance of exhaust air is exhausted from 2nd exhaust hole according to the rotation of rotor. The direction of air-supply and exhaust air for counter-rotation is completely in reverse.