DeWalt DW66C-1 Guide D'utilisation page 9

WARNING: To reduce the risk of personal injury, disconnect tool
from air supply before performing maintenance, clearing a jammed
fastener, leaving work area, moving tool to another location or
handing the tool to another person.
Trigger
WARNING: Always wear proper eye [ANSI Z87.1 (CAN/CSA
Z94.3)] and hearing protection [ANSI S12.6 (S3.19)] when operating
this tool.
WARNING: The operator must not hold the trigger pulled on
contact trip tools except during fastening operation, as serious injury
could result if the trip accidentally contacted someone or something,
causing the tool to cycle.
WARNING: Keep hands and body away from the discharge area
of the tool. A contact trip tool may bounce from the recoil of driving a
fastener and an unwanted second fastener may be driven, possibly
causing injury.
WARNING: Never use rafter hook to hang tool from body, clothing
or belt.
CONTACT TRIP (BLACK TRIGGER)
The common operating procedure on "Contact Trip" tools is for the
operator to contact the work to actuate the trip mechanism while
keeping the trigger pulled, thus driving a fastener each time the work
is contacted. This will allow rapid fastener placement on many jobs,
such as sheathing, decking and pallet assembly. All pneumatic tools
are subject to recoil when driving fasteners. The tool may bounce,
releasing the trip, and if unintentionally allowed to recontact the work
surface with the trigger still actuated (finger still holding trigger pulled)
an unwanted second fastener will be driven.
SEQUENTIAL TRIP (GRAY TRIGGER)
The Sequential Trip requires the operator to hold the tool against
the work before pulling the trigger. This makes accurate fastener
placement easier, for instance on framing, toe nailing and crating
applications.
The Sequential Trip allows exact fastener location without the
possibility of driving a second fastener on recoil, as described under
Contact Trip.
The Sequential Trip Tool has a positive safety advantage because it
will not accidentally drive a fastener if the tool is contacted against
the work – or anything else – while the operator is holding the trigger
pulled.
CONTACT TRIP OPERATION (BLACK TRIGGER)
When using the contact trip (black) trigger the tool contains a contact
trip that operates in conjunction with the trigger to drive a fastener.
There are two methods of operation to drive fasteners with a contact
trip tool.
SINGLE FASTENER PLACEMENT: To operate the tool in this
manner, first position the contact trip on the work surface, WITHOUT
PULLING THE TRIGGER. Depress the contact trip until the nose
touches the work surface and then pull the trigger to drive a fastener.
Do not press the tool against the work with extra force. Instead, allow
the tool to recoil off the work surface to avoid a second unwanted
fastener. Remove your finger from the trigger after each operation.
RAPID FASTENER OPERATION: To operate the tool in this manner,
hold the tool with the contact trip pointing towards but not touching
the work surface. Pull the trigger and then tap the contact trip against
the work surface using a bouncing motion. Each depression of the
contact trip will cause a fastener to be driven.
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