| For Deep-Hole Peck
Drilling
The Blackalloy™
Model 150 and Model 250 Series Drill Units are available with
up to 6" Peck Drill Control. The Drill Unit is factory
equipped with a special Peck Feed Cylinder and Pneumatic Control
Kit which together perform the Peck Drill Control. Peck Drill
Control can also be added in the field to any Model 150 or
250 Drill Unit.
Pecking
Models include a special Pneumatic Control Kit which does
not require any electrical wiring. The drill cycle is achieved
by a modular pneumatic control unit that includes two timers.
The timers control the length of time for the forward and
return strokes. The forward stroke time is directly related
to the drill depth increment per cycle. These times are easily
tailored in the field to any drilling situation that may be
encountered.
The special
Peck Feed Cylinder performs three functions. It allows a rapid
advance to a point only slightly before the drill contacts
the work. This minimizes the cycle time. It's second function
is to control the feed rate during the actual drilling portion
of the cycle. This rate, which is easily adjusted, is precisely
controlled through the unit's leak proof hydraulic metering
system. The final function of the Peck Feed Cylinder is to
"remember" the last drill depth during the return
cycle. It does this by a built-in clamping system that locks
the cylinder during its return stroke. The subsequent forward
stroke begins at the previous cycle drill depth. This allows
the cycle time to be minimized for optimum performance and
prevents damage to the drill bit when the drill re-enters
the hole.
This repeat
cycle continues until the hole has been drilled to the desired
depth. This depth can be set on the Drill Unit to within a
few thousands of an inch by using the stop rod assembly which
is a standard feature of every Drill Unit. At the same time
as the desired drill depth is reached a pneumatic limit switch
is tripped to signal the Dill Unit to retract to the home
position and wait for the next drill cycle. |
