ElEctric winDscrEEn wiPErs
Our Fuzz clears our vision on the history and intricacies of vehicle windscreen wipers EvErything you nEED to know
‘Opening screens meant drivers had to wear goggles. And were usually wet’
Iadmit to having a peculiar enthusiasm for car windscreen wiper equipment stretching back to my early childhood, probably from sitting up front in early rear-engined buses, with their peculiar wiper mounting arrangement of one at the top of the driver’s screen and the other at the bottom of the nearside. Rides in ancient Land Rovers fitted with individual unsynchronised motors for each wiper, and the occasional Jaguar E-type passing by with all three arms on the go at once cemented my fascination.
In the earliest days of the car, the problem of forward vision in rainy conditions was addressed by the provision of an opening windscreen, although this meant that drivers had to suffer stinging eyes or wear goggles. And were usually wet.
Enter the rubber wiper blade, initially mounted via a spindle to a hand-operated arm. These had the disadvantage of taking one of the driver’s hands away from the steering wheel, thus displacing the potential cause of an accident from lack of vision to lack of control. One heavyweight electrically-powered solution saw a vertical wiper blade drawn side-to-side across the screen, the advantage here being that all of the screen area was cleared with each sideways wipe. But it was a cheaper solution that won the day.
Enter the arc-sweep windscreen wiper, which is still with us today. Some manufacturers avoided taxing the puny charging systems of their cars by utilising the readily available vacuum power supply from the engine’s inlet manifold. But without the installation of a reservoir, this meant that the directly scavenging wiper motor went like the clappers under heavy engine loads but crawled agonising slowly under cruising conditions, generally reversing the requirements for screen clearing. Ford persisted with this system until 1961, long after its mainstream rivals had given up on it.
The way forward was the electric motor-powered arc-sweep wiper, at first largely only installed on the driver’s side of the windscreen. Over time, a second wiper was fitted to improve screen clearance, these being operated either by an additional motor or a direct mechanical linkage. Sometimes a simple rod was used, then eventually a flexible rack. The latter allowed the motor to be tucked neatly away and synchronised the wiper arms, allowing a greatly increased sweep of the screen area and better forward vision.
Progress never stands still and so rather than the driver determining the resting position of the wipers, an automated parking facility was introduced. This saw the wipers returning to a pre-determined parked position, often tucked away neatly beneath the bonnet line, providing an unspoilt outward appearance and greater aerodynamic efficiency.
Modern cars use largely the same system, though often with more complex operating linkages for even greater screen sweep coverage.