The loading of a motor truck is very much the same proposition as the
loading of a flat-car. The principal difficulties that trucks have had
to contend with have been poor roads and inefficient methods of loading.
In loading, the main trouble has been in regulating the yarding so that
a supply of logs is always on hand. The use of the gin pole and crotch
line operated by the straw drum of the yarding donkey ties up the
yarding until the truck is loaded. This is being overcome by using a
separate engine with the high lead for yarding and doing the logging
independently of the yarding as is done in the case of railroad logging.
In this way the yarder can keep ahead of the loading engine and there
will be no delay at the landing.
Most of the larger companies load with the Duplex loader and use tongs.
This is a safer way to load than with the crotch line as the logs can be
more easily controlled. The danger of dropping a log through the truck
or of knocking off the top of the truck or the driver's seat is greatly
lessened.
In pole and piling timber where a skid road and horses are used, loading
is done by hand or with a team. A landing is built of cribwork and the
logs are simply rolled on the truck with peavies or cant hooks, or a
parbuckle system with skids and horses is used. This works fairly well
for small operations in small timber.
[Illustration: Loading a motor truck and trailer through the use of a
boom.]
The latest development in loading is the boom. An illustration of this
method is shown above. The boom itself is a fifty to sixty foot pole
about eighteen inches in diameter at the base and is attached to the
spar tree by means of a metal strap with two lugs which are fitted into
holes bored in the spar to keep the strap from slipping. The base of the
boom is fitted with a metal joint which moves freely on an upright pin
set in the metal strap. (See A, above.) The whole rig is set high enough
on the tree so that it may be swung in a semi-circle and clear the
loaded truck by several feet. A light line (B) from the haulback drum of
the donkey passes through a block attached low on the spar tree and
thence to another block on a stump to the right of the landing. From
here it passes through a third block at the end of the boom and back to
the stump again. This secures the needed pulling power from the haulback
drum.
The lifting line from the mainline drum passes through a block half way
up the tree and thence through a free swinging block (C) and back to the
tree again. On the second block is a ring to which two one inch lines
(D) are attached. These lines pass through the boom stick on rollers (E)
about fifteen feet apart. On the ends of these lines hooks are attached.
These two lines should be so arranged that the hooks remain parallel to
the ground. Two three-quarters inch cables (F) with an eye splice in
each end are attached to the hooks. These lines, or chokers, are then
wrapped around the log and it is lifted clear of the ground by means of
the block hold in the main line.
The haulback line (B) from the donkey is slacked and the boom travels
over to the truck by means of a line (G) attached from the boom to a
dummy log running on a special guy line. A log two feet in diameter and
sixteen feet long is wrapped at each end with a cable and fastened to a
pulley. The two pulleys and attached dummy log travel up and down the
guy line as the boom moves. A line is attached to the boom and runs
through a pulley attached to the dummy log and extends back to the boom
again. This pulls the boom over above the truck as the dummy log travels
down the guy line. The logs are held parallel to the ground above the
truck and the truck is run under the boom to the location designated by
the head loader. With this system the logs will not drop suddenly on the
trucks as the log will fall off while being carried over to the truck if
there is any danger of its falling at all. After the log is placed, the
boom is pulled back to the landing by the haulback line. This system has
worked with success in a number of motor truck operations and is a safer
method than loading with tongs because the logs cannot accidentally drop
and injure the truck. However, the loading situation should be studied
carefully. The most efficient loading device for the particular needs of
the operation may be installed as any loss of time in loading seriously
affects the output of the operation.
Most of the truck loggers unload their logs into water; either into a
lake, a river that can be driven, or into tide-water. A few, however,
unload directly into the log pond at the mill or at the log yard in case
the mill has no log pond.
The road is usually planked solid at the unloading ground. A great help
in unloading is a dock from six to twelve inches higher on one side
than on the other so the logs will roll off the truck easily. The
brow-skid should be close to the log bunks and just a little lower than
these when the truck is tilted. When unloading into shallow water, such
as a small river, six or eight skids a foot and a half in diameter are
placed so that they slope from the brow-skid to the water at an angle of
forty-five degrees. An illustration of this method of unloading is shown
below. The skids are so placed that the unloading ground will not be
undermined.
[Illustration: Unloading truck and trailer through the use of an
incline, showing brow-skids and roll-way.]
When the truck comes to a stop on the incline, the chock blocks are
released from the opposite side and the logs roll off of their own
accord. In some instances a gill-poke has been used in connection with
the unloading incline, the logs being sheared off as the truck moves
ahead. Usually the logs roll off readily without the use of the
gill-poke and if a load does stick it can be loosened with a cant-hook,
so that the gill-poke really is unnecessary.
Unloading on public wharves or roads where no permanent incline can be
used is accomplished by placing a portable wedge-shaped timber in front
of the outside truck and trailer wheels and driving upon it.
[Illustration: Parbuckling a load of logs from the truck and trailer.]
In the most efficient way of unloading the usual brow-skid is placed a
few inches below the log bunk and the logs are parbuckled from the truck
and trailer, an illustration of which is shown above. The trucks are run
on an incline so that one side is raised about four inches. A
crotch-line consisting of two half-inch cables is attached to the
brow-skid and passed under the logs to a ring fastened to an inch cable.
The larger cable passes thru a block located on a gin pole. A light
yarding or a land clearing donkey furnishes the power to parbuckle the
logs into the water. By this method the logs are lifted from the truck
as they are rolled into the water with little danger of the top log
dropping on the log bunk as is often the case when other methods are
used, resulting in expensive repairs for broken springs or bearings.