An overhead traveling crane may be utilized to move loads within a building or other structure. Such cranes may use structural ceiling beams of a building to travel along, for example. The ambient environment in which such cranes operated typically did not require a crane to be configured to minimize emission of contaminants into the crane's ambient environment. For example, hoists of prior art cranes were not configured to prevent oils, lubricants, and other contaminants from being emitted to such an ambient environment.
The use of hoists and cranes in clean rooms or clean zones for manufacturing certain products require that particular particulate cleanliness standards be met. Examples of such standards are outlined in “Federal Standard 209E Airborne Particulate Cleanliness Classes in Clean Rooms and Clean Zones”, Institute of Environmental Sciences, 1992, which is incorporated herein by reference. Since it is sometimes necessary for cranes to operate in clean rooms and clean zones, it is desirable for cranes utilized therein to minimize the emission or production of particulates.
Thus, a need exists for cranes, which do not introduce contaminants or particulates into their ambient environment particularly when such cranes are located in clean rooms.