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tech
jeepfan.com
Guide to a Jeeper's Garage
Air Tools
Impact
Wrench
An impact wrench also known as
an impact gun is a pneumatic tool that typically uses socket
driven by a rotating mass striking the output shaft.
This motion causes the well known sound of the impact wrench
and also is responsible for the increased torque that is
helpful when removing nuts and bolts.
Compressed air is the most
common source of power in impact wrenches, there are also
electric, cordless electric, and hydraulic models available
too.
Impact wrenches come in
varying sizes and torque powers and usually are reversible.
They also come in varying socket sizes to fit 1/4" drive all
the way to 1" and on. While it is possible to use
standard sockets on an impact
 wrench
it is recommended that special impact wrench grade sockets
are used since standard sockets may not take the pounding.
In addition, impact sockets are constructed of very hard
metal that has very little spring effect that will greatly
reduce the torque. Use of extensions or universal
joints will reduce the impact torque also.
Operation detail
A rotating mass (the hammer) is accelerated by the
motor, storing energy, then suddenly is connected to the
output shaft (the anvil), creating a high-torque impact. The
hammer mechanism is designed such that after delivering the
impact, the hammer is again allowed to spin freely, and does
not stay locked. With this design, the only reaction force
applied to the body of the tool is the motor accelerating
the hammer, and thus the operator feels very little torque,
even though a very high peak torque is delivered to the
socket. This is similar to a conventional hammer, where the
user applies a small, constant force to swing the hammer,
which generates a very large impulse when the hammer strikes
an object. Energy is stored over time, allowing a very
strong, but short output impulse to be generated from a
relatively weak, but constant input force. The hammer design
requires a certain minimum torque before the hammer is
allowed to spin separately from the anvil, causing the tool
to stop hammering and instead smoothly drive the fastener if
only low torque is needed, rapidly installing/removing the
fastener.
Impact sockets and accessories
As discussed earlier impact sockets are purpose built
but many varieties exist. Standard size and deep
sockets, universal joints, and extensions are all available
in SAE and metric sizes.
Universal Joint |
Extension Set |
Standard Socket |
Popular Impact
Wrench
Manufacturers and Resellers
Craftsman
SnapOn
Matco
Husky
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