Page 81 - 诺霸英文2022

POWERED TORQUE TOOLS

TORQUE REACTION

This page applies to both HandTorque® multipliers and powered torque tools

Red shading indicates ideal area for
torque reaction.
It is not advised to react outside of the
shaded area.

Signs of poor reaction are evident on this damaged foot.
Reaction was taken at the wrong point on the foot and burring
indicates that the foot was slipping off the reaction point.

Points to remember

• Take the reaction as far away from the multiplier as practical
• Ensure that the reaction point remains square to the multiplier wherever possible as this will minimise any additional stress in
the output square, which could result in premature failure. If the multiplier tilts under load, the reaction may not be square
• For applications that do not allow the reaction to be taken securely it is advisable to use a double-sided or balanced reaction
plate

Reaction Force
When using multipliers and PneuTorques the reaction point must be capable of withstanding the reaction force. Therefore, great
care must be exercised where the reaction is taken when applying high torques to studs and bolts.
By using the following formula you can calculate the force at the point of reaction. The greater the distance the lower the force.

D = Stud Diameter
π x D² Reaction Force
Formula to calculate Area of Stud = Formula to calculate shear force: Shear Force =
4 Area of Stud
What to do if the standard reaction device is not suitable

For those applications that do not permit the use of a standard reaction plate the customer has three options.
• Norbar or an authorised Norbar distributor will design and manufacture a special purpose reaction plate to the customer’s
requirements
• The customer can modify the standard reaction plate to suit their requirements
• The customer can fabricate their own reaction device after liaison with Norbar’s technical department or a Norbar distributor
Customers wishing to either modify the original reaction plate or fabricate their own device should read the above information on
how to avoid common torque reaction problems.

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