TYPES AND USES - Continued
TORQUE WRENCHES (Cont)
A scale torque wrench has a rod which runs parallel to
the handle and the drive element. This rod moves
across the scale to the right or left as torque is applied.
POWER TORQUE WRENCH
Using a powerful gear train, the power torque wrench is
completely mechanical in operation. The power torque
wrench is operated by a hand crank. The torque is
calibrated in foot pounds, which is shown by a dial
indicator on the top face of the power torque wrench.
This type of torque wrench is used for tightening nuts
and bolts requiring 200 or more foot pounds of torque.
A special feature of this type of
torque wrench is that it is possible to
loosen as well as tighten nuts and
Two basic types of spanner wrenches are the hook-type
and the pin-type. Hook-type spanner wrenches are
either fixed or adjustable and are normally used to
tighten fire hoses or similar couplings which have a
protruding lip. Pin-type spanner wrenches have pins
protruding from the handle which fit into holes in the
coupling or plate to be tightened or loosened. Spanner
wrenches are special purpose wrenches and are to be
used only for their intended purpose.
Three kinds of hook-type wrenches include the hose
coupling pin, for tightening and loosening hose
couplings, the fixed hook, for tightening or loosening
couplings with protruding rims or edges, and the
The adjustable hook-type is similar to the fixed hook-
type. However, it may be adjusted around objects and
fastened before use.
25-12 Change 1