Page 28 - Moving the Earth_ The Workbook of Excavation

LAND CLEARING AND CONTROLS

1.28 THE WORK

Pulling Small Growth. Brush and small trees often grow where they cannot be reached by pusher
machinery, because of soft or rough ground or nearness to buildings. A landowner may wish to do
her or his own clearing without hiring a dozer. Hand cutting may not be satisfactory because of
sprouting. In such cases pulling techniques will be applied to small growth.
An automobile has sufficient power for pulling some brush and small, stiff-trunked trees, but
the work does not do it any good. Trucks and farm tractors usually put more power on the job and
are less likely to be damaged by the exertion.
If the stems are stiff, fastening may be made high for leverage. If they are flexible, height does
not matter, and the greater strength of the base may make it the best place.
Chains tend to slide along smooth stems, and they often can be made to grip by wrapping once
or twice around before fastening. Light chain with small links holds much better than coarser
types. A round hook or ring should be used to make a choker. If stems are close together, it is often
possible to pull several at a time by putting a single choker around the group. It will slide up until
it can pull them all tight together and then should hold.
Brush tongs get a good grip on small trees and flexible plants, and are easy to attach and to
remove, but their weight may outweigh these advantages.
Plants too well rooted to respond to the power available may be weakened by digging out and
cutting roots, or pulleys may be used to step up the power.

WINCHES

Power to pull stumps may be supplied by almost any machine or by animals. The crawler tractor is
preferred for heavy work, but wheel tractors and trucks may also be used. However, the most power-
ful, most convenient, and best controlled pull is obtained from winches. These are most efficient
when mounted on crawler tractors, but may be on wheel tractors or trucks, or may be portable units
operated by a hand crank.
For general clearing work, the most effective tool is a dozer carrying a power winch. The
winch consists of a heavy spool drum that is mounted on the back of the tractor and driven by the
power takeoff. It is controlled by the tractor main clutch and the power takeoff engagement lever.
In addition it may have a transmission, giving rotation of the drum in either direction, and in large
machines permitting several speeds of rotation. A jaw clutch or neutral gear is used to disconnect
the drum from the driveshaft, to allow it to turn freely when the cable is being removed. A brake
is provided to slow or lock the drum when necessary.
The winch may hold 200 or more feet of cable of a size proportionate to its power. Additional
cable can be carried on a separate spool and connected to the winch cable by a choker device when
needed.
In small sizes, the winch cable generally is fastened at the working end to a short piece of chain
equipped with a round hook. Larger cables may be fastened directly, or through a swivel or single
link, to a round hook, or a wide-face cable grip hook. The cable is generally underwound on the
drum, that is, leads from the work to the lower part of the drum. This gives better stability under
heavy load than overwinding.
Stump Pulling. To winch out a stump, the tractor should be placed facing directly away from
it, and both brakes locked on. The winch jaw clutch should be released, its brake set to drag very
slightly, and the cable pulled to the stump by hand. If the brake is not used, the drum may con-
tinue to spin after being pulled, and unwind and snarl the cable.
If the winch will not freewheel, or the cable is very heavy, the drum is turned backward by the
engine to pay it out. It is convenient to have two operators, one to operate the winch and the other
to pull the cable. If no helper is available, the operator can stand near the winch while it turns,
stripping the cable and coiling it on the ground until there is enough. The operator then stops the
winch and drags the cable to the stump. The cable must then be whipped up and down and the twists
worked out to avoid kinking when pulled.