ERGONOMICS OF MANUAL MATERIALS HANDLING - Environmentally Conscious Materials Handling - page 52

Figure 2.5 Typical triaxial manipulator (from Woldstad and Reasor 1996)

location. Hoists are a good solution when a load must be lifted and moved within
a fixed space. They are not good solutions when the load must be transported
long distances or when the work area is crowded with other devices or people.
Note that when a hoist is employed, the lifting-holding-carrying components of
the materials handling job are replaced with pushing-pulling components.

3.1.2 Lift Tables
Lift tables function to lift or lower an object and hold it in position so that
it can be grasped or manipulated (see Figure 2.6). They can often be used to
improve the vertical multiplier (VM) and the horizontal multiplier (HM) for a
lifting task. They can also reposition the work area to allow manipulation and
assembly operations to be done at an optimal work height. Some lift tables have
a rotating and/or tilting top to help workers position the load closer to their body
(thereby reducing the HM). Lift tables should be used when lifting is repeatedly
done from a fixed location. They are particularly effective when used for stacking
and unstacking operations. Note that lift tables eliminate manual lift and hold
tasks, but they often require the worker to manually lift the load from the table
and carry it to a different location.