American inventor Mary Anderson is credited with designing the first operational windscreen wiper in 1903. In Anderson’s patent, she described her invention as a ‘window cleaning device’ for electric cars and other vehicles. The windscreen wiper has since remained one of the very few parts of a motor car which has lasted for well over one-hundred years virtually unchanged.
Why hasn’t anyone come up with a more hi-tech solution for clearing rain and water from windscreens than a rubber squeegee?
Until there is a radical breakthrough, we have to rely on this simple design. A flexible ‘blade’ is the best way to remove a coating of liquid from glass; when fluid (air, water, whatever) moves against a surface, the fluid in contact with the surface doesn’t move, it ‘sticks’ to the surface. As you move away from the surface the speed of the fluid increases until it is at the same speed as the flow.
The concept of hydrophobic coatings is a great idea for glass, but airflow is still needed to make them most effective. The ‘beading up’ of water is the nano-coating working to repel the liquid but until there is force (airflow) the bead will not move as effectively as it is being repelled in all directions to prevent it from rolling away.
For now, long live windscreen wipers.