Impact wrenches achieve an enormous torque and are therefore used in many workshops and other home maintenance needs such as window repairs. If you are only in a car repair shop for five minutes, you can almost always hear the familiar rattle of the screwdriver. Here, wheels are dismantled, new ones attached, or rusty and stubborn screws loosened. Read a review of DeWALT impact driver body only.
Impact wrenches are mainly used in professional workshops because they are quite special and do not have a wide range of uses. In addition, there is the fact that compressed air tools have their advantages especially in the professional sector, and are increasingly being used there. Therefore, many people connect the impact wrench to the compressed air.
What you should look for when buying impact drivers?
Cordless screwdrivers, hammer drills, and impact wrenches are often lumped together and compared with one another. While cordless screwdrivers and hammer drills are still similar and have the same basic structure despite completely different names, the impact wrench is completely out of line here and can hardly be compared with other drilling and screw driving tools.
Typical drilling and screwing tools obtain their torque (torque or screwing force ) from the power of the motor. A gearbox supports and increases the power of the motor, but if the limit is reached, the motor stops or an overload clutch responds.
An impact wrench has no direct connection between the motor and screwdriver and can therefore not be blocked.
A type of coupling (similar to the torque setting on cordless screwdrivers) ensures that the motor spins when a certain torque is reached, which only drives the screw drive in jerks and thus activates the impact function, which achieves the high torque and represents the actual function of the pneumatic impact screwdriver.
How does an impact wrench work?
If a screw/nut is difficult to loosen or if particularly high torque is to be achieved when screwing, a longer lever is often used or a wrench is attached and set in rotary motion with hammer blows. Although this method does not achieve a rapid rotary movement, it does achieve an extremely high torque. The impact wrench uses a similar principle.
Two contour disks – similar to an overload clutch – lie on top of one another in a form-fitting manner and continue to rotate the motor. If a certain torque is required, the disks pressed against each other by spring force are pressed apart and the motor continues to turn, but the screw drive stops for a short time.
After a short turning movement, the disks snap back into place and the contours strike against each other in the direction of rotation. This generates the impact energy that achieves a higher torque than the drive motor itself. This method is often implemented using balls or rollers that roll on the contour disk, striking an obstacle and striking it.
If the screw drive stops due to the required torque, the balls or rollers roll over the obstacle, complete their rotary motion, and strike the obstacle again. If the required torque is very high, the motor keeps turning while the screw drive almost stops and is only moved jerkily by the impact force. The typical “crackling” occurs, as is often heard in car workshops.
This can easily be visualized with a small round rod (or nail) that is pressed against the teeth of a saw blade. As long as the saw blade can be moved, the rod remains stuck in the toothing and transfers the movement. If the saw blade is difficult to move, the round rod will eventually slip out of the valley of the toothing, move on, and hit the next tooth. The movement is now only transmitted jerkily, but with more force due to the blows against the teeth.