Mechanical Design
Simplistically, mechanical design is the design of mechanical systems, not just mechanical components. It is concerned with entire systems and their functional design, from the conceptualisation stage.
A mechanical design may include a lot of different parts, spread over a large area, that make up the entire system. Examples are the heating, ventilation and air conditioning system in a large building. Or factory machinery that make up an entire production line. Or a elevator transportation system in a very tall building.
Mechanical engineers are responsible for the design of all the little components that make up the system. Using the example of the elevator system: mechanical engineers will design the elevator units, the motors and geartrain that move the lifts and the pulleys and cables that carry them. They will be responsible for designing all the components that are fitted to the elevator shafts, in collaboration with the architects and planners that designed the building.
The mechanical design part comes to the fore when the decisions have to be taken how many lifts there must be, how many floors they must cover and how the software programming will be done to transport people most efficiently around the building. The fuzzy logic and planning that are integral to such a system is a science all by itself.
Modern, high-speed elevators do not stop at every floor. It would make no sense to take the elevator to the fiftieth floor if it is going to stop at every floor in between! Therefore, there must be several elevators, each covering a decent distance before stopping, to enable it to reach a high speed by skipping many floors. The elevators must stop at staggered intervals, to ensure that nobody waits for an elevator for too long, yet also that nobody spends too much time in the elevator. The predictive software programming that goes into a system like that can boggle the mind.
The mechanical design is successful if the elevator system performs unobtrusively and effectively, working together as an entire system to ensure that the call of every pressed button is heeded within a reasonable time.