Motor Truck Logging Methods: Engineering Experiment Station Series, Bulletin No. 12Knapp, Frederick Malcolm
Science
Motor Truck Logging Methods: Engineering Experiment Station Series, Bulletin No. 12
Knapp, Frederick Malcolm
Lumbering
[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.
TIME STUDIES
Time is a very important item in loading and unloading. Usually the most
time is consumed in loading, for which reason any improvement that will
reduce the time taken to load will greatly increase the efficiency of
the operation. With the proper unloading devices, the truck may be
unloaded in the time required to knock down the chock blocks.
The following table is a record kept for one day of the actual time
taken by a truck at each step in the hauling of logs at one operation.
However, it is possible to give only arbitrary figures to fit the
particular operation of which they are taken. No average figures can be
given that fit all conditions.
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