Norbar HandTorque Multipliers0 pages

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Handtorque™ Multipliers
What is a Torque Multiplier?
A torque multiplier is a device that increases the torque that can be applied by an operator. Because the power output
can not exceed the power input, the number of output revolutions will be lower than the number of input revolutions
(Torque x rpm = Power).

How Handtorque™ Torque Multipliers Work
Handtorque multipliers incorporate an ‘epicyclic’ or ‘planetary’ gear train having one or more stages. Each stage of
gearing increases the torque applied by a factor of 5, allowing Norbar to offer multipliers typically in ratios of 5:1, 25:1
and 125:1.
In the planetary gear system, torque is applied to the input gear or ‘sun’ gear.Three or four planet gears whose teeth
are engaged with the sun gear therefore rotate.The outside casing of the multiplier, or ‘annulus’ is also engaged with
the planet gear teeth, and would normally rotate in the opposite direction to the sun gear. A reaction arm prevents
the annulus from rotating, and this causes the planet gears to orbit around the sun.The planet gears are held in a
‘planetary’ carrier which also holds the output square drive.Therefore as the planet gears orbit around the sun gear,
the carrier and so the square drive turns.
Without the reaction arm to keep the annulus stationary, the output square will not apply torque.

Why use a Handtorque™ Torque Multiplier?
• Safety – use of long levers can be dangerous.Torque multipliers mean a reduction
in the lever length or operator effort by a factor of 5, 25 or 125.
• Space limitation – the use of a long lever may be impossible due to the available space.
• Accuracy – torque will be applied most accurately when it is applied smoothly and slowly.
Torque multipliers enable this by removing much of the physical effort from the
tightening task.

25 revolutions

Input 100 N.m

Torque
Velocity
Without a torque multiplier

Output 2500 N.m

With a torque multiplier
0.84 revolutions

32

Norbar - Total Torque Control