Page 29 - Moving the Earth_ The Workbook of Excavation

LAND CLEARING AND CONTROLS

LAND CLEARING AND CONTROLS 1.29

The winch cable may be put around the stump directly, may be hooked to a choker chain or
cable, or may be run through one or more snatch blocks.
Power is applied to the winch and the cable is reeled in, care being taken to see that it feeds
onto the drum properly. The stump may come out or the tractor may be dragged backward. If the
latter, the tractor may be anchored by a chain from the blade or front pull hook to a tree. Resistance
to pull may also be increased by backing it against a log or bank, or by trying to pull the stump by
tractor pull and allowing the tracks to spin until they have built mounds behind them. If the
anchoring or blocking is effective, the stump will come out—if nothing breaks, slips, or stalls.
The drum carries a number of layers of cable so that it has a greater spool diameter full than
empty. It therefore reels in cable more slowly and powerfully on a bare drum than on a full one.
On a bare drum, logging winches will give 50 to 100 percent more pull than the tractor itself; on
a full drum, the same pull as the tractor or somewhat less. But with torque converter drive,
strongest pull may be with a full drum.

Jammed Cables. Using a nearly bare drum not only gives the greatest pull but also reduces dam-
age to the cable. If a long cable is wound smoothly onto a drum under moderate tension, and a
heavy pull applied when it has built up several layers, the last wrap may squeeze between the
wraps below, as in Fig. 1.21(A). This scrapes and wears the cable and jams it so that it will not
spool off again. The best way to free it is to turn the drum until the catch is in the position shown
in (B), and jerking it, or anchoring the end and driving the tractor away. Or, in the same position
on the drum, the cable may be given a couple of wraps around the drawbar, and the winch turned
backward as in (C).
If the cable is wound unevenly onto the drum, with the wraps crossing each other at random,
it cannot cut down between lower layers readily, but may put severe kinks in sections of cable that
cross under it, and this cross wrapping may not entirely prevent it from squeezing in and sticking.
In spite of these difficulties, a long cable is desirable for general work. If reasonable effort is
made to spool it in evenly while working, it will usually be rough enough to prevent excessive
sticking, without too much bending or crushing.

Two-Part Line. Where the distance to the stump is less than one-half the cable length, a two-
part line may be used by attaching a pulley to the stump and by running the line from the winch
around the pulley and back to the drawbar. The useful strength of the cable and the pull between
the tractor and the stump are doubled.
The tractor may have to be backed against a heavy log or an outside anchor used in the manner
to be described below. The tractor should not be anchored by the front pull hook while using a
double line anchored on the drawbar, unless the manufacturer states that it is strong enough to take
the strain.
Rocking. The winch and tractor pulls differ in quality, and it may happen that the pull of the tracks
will do jobs that the winch will not. Use of the tractor drive helps in “rocking” stumps or trees out.
The line is left slightly slack, and the tractor moved forward in low. As the line tightens, the stump
may lean a few inches, then stop. When the tracks start to spin and the clutch is released, the weight
of the stump, combined with the spring in the roots and in the line, will pull the tractor back. The
clutch is immediately reengaged and held until the tracks spin or the engine lugs down again.
If the stump is within the tractor’s power range, repeating this maneuver should gradually break
it out. A long cable has more elasticity than a short one, or a chain, and will be more effective at
rocking.
This procedure should not be allowed to degenerate into yanking, where the tractor is given a
long enough slack run to be brought up with a jerk when it tightens. This will break more tractors
and cables than it will pull stumps.

Cable Breakage. Cable or chain breakage is a serious danger to both operator and helpers. A
cable particularly stretches under strain, and if it breaks suddenly, it may whip with great force.
The danger to the operator is greatest if the break is fairly near him or her. The cable used should