Adjusting the Speed
The speed of the switched on power tool can be variably adjusted, depending
on how far the On/Off switch is pressed. Light pressure on the On/Off switch
results in a low rotational speed. Further pressure on the switch results in an
increase in speed.
Usage Advice
Apply the power tool to the screw/nut only when it is switched off. Rotating
tool inserts can slip off. The torque depends on the impact duration. The
maximum achieved torque results from the sum of all individual torques
achieved through impact.
The maximum torque is achieved after the impact duration of 6–10 seconds.
After this duration, the tightening torque is increased only minimally. The impact
duration is to be determined for each required tightening torque. The actually
achieved tightening torque is always to be checked with a torque wrench.
When working with an application tool, pay attention that the application tool is
firmly seated on the tool holder. When the application tool is not firmly
connected with the tool holder, it can come loose again and not be controlled.
Screw Applications with Hard, Spring-loaded or Soft Seat
When in a test, the achieved torques in an impact series are measured and
transferred into a diagram, resulting in the curve of a torque characteristic. The
height of the curve corresponds with the maximum reachable torque, and the
steepness indicates the duration in which this is achieved.
A torque gradient depends on the following factors:
•
Strength properties of the screws/nuts
•
Type of backing (washer, disc spring and seal)
•
Strength properties of the material being screwed/bolted together
•
Lubrication conditions at the screw/bolt connection
The following application cases result accordingly:
•
A hard seat is given for metal-to-metal screw applications with the use of
washers. After relatively short impact duration, the maximum torque is
reached (steep characteristic curve). Unnecessary long impact duration
only causes damage to the machine.
•
A spring-loaded seat is given for metal-to-metal screw applications,
however with the use of spring washers, disc springs, studs or screws/nuts
with conical seat as well as when using extensions.
•
A soft seat is given for screw applications, e.g., metal on wood or when
using lead washers or fibre washers as backing. For a spring-loaded seat
as well as for a soft seat, the maximum tightening torque is lower than for
a hard seat. Also, longer impact duration is required.
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