ElEc­tric winD­scrEEn wiPErs

Our Fuzz clears our vi­sion on the his­tory and in­tri­ca­cies of ve­hi­cle wind­screen wipers Ev­Ery­thing you nEED to know

Classic Car Weekly (UK) - - LIVING WITH CLASSICS - fuzz town­shend ccw’s mas­ter me­chanic

‘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.

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