Doosan DX180LC, Руководство по ремонту

Страница: 100 / 110

SP000017 Standard Torques
Page 12
TORQUE WRENCH EXTENSION
TOOLS
Very large diameter, high-grade fasteners (nuts, bolts, cap
screws, etc.) require a great deal of turning force to achieve
recommended tightening torque values.
Common problems that could occur as a result are:
• Recommended torque exceeds the measuring
capacity of the torque wrench.
• Specialized sockets do not fit the adapter on the front
end (nose) of the torque wrench.
• Generating adequate force on the back end (handle)
of the wrench is difficult or impossible.
• Restricted access or an obstruction may make use of
the torque wrench impossible.
• A unique application requires fabrication of an
adapter or other special extension.
Most standard torque wrenches can be adapted to suit any one
of the proceeding needs or situations, if the right extension tool
is used or fabricated.
Torque Multiplication
A wrench extension tool can be used to increase the tightening
force on a high capacity nut or bolt.
For example, doubling the distance between the bolt and the
back (handle) end of the torque wrench doubles the tightening
force on the bolt. It also halves the indicated reading on the
scale or dial of the torque wrench. To accurately adjust or
convert indicated scale or dial readings, use the following
formula:
I = A x T / A + B where:
I = Indicated force shown on the torque wrench scale or dial.
T = Tightening force applied to the nut or bolt (actual Torque).
A = Length of the torque wrench (between the center of the nut
or bolt and the center of the handle).
B = Length of the extension.
As an example, if a 12" extension is added to a 12" torque
wrench, and the indicated torque on the dial reads "150 ft lb,"
the real force applied to the bolt is 300 ft lb:
Figure 1
I =
A x T
=
12 x 300
=
3600
= 150
A + B 12 + 12 24