The table
above should be used as a general guideline only. The
manpower requirements to push & pull a load varies greatly and
are mostly influenced by two factors:
-
Floor
conditions: It is easier to move a load on smooth and
level concrete surfaces than on rough and uneven ground.
-
Weight per
footprint: It is less difficult to move a load on a larger
dolly than on a small dolly; as more rollers are available to
support the weight, there is less weight for each individual
roller to carry. Since each roller has less pressure placed on
it, the load becomes easier to move.
Understanding Break-Out resistance and Rolling
resistance
It is harder to get the load to start moving than to keep it
moving. The force required to start the load moving from a
standstill to a rolling state is called the break out
resistance.
This break out
resistance is approximately. 5-10%
of the load weight,
depending on the factors mentioned above.
Once the load
is rolling, it becomes easier to move. The rolling
resistance is approximately 1/2 of the break out
resistance and requires
only half of the force to keep the load moving.
Safety first
Please do not underestimate the braking force required to stop
the load from moving. If you have ever pushed a stalled car, you
know how difficult it is to stop a rolling vehicle. For loads over 6 tons we highly recommend
using a forklift or puller to be able to stop the load when
necessary. If you operate any heavy load on a decline,
ALWAYS use a forklift to avoid run-away loads. |