How to Guides

Windshield Wiper Blade

Zaki Moulvi posted this on Jun 16, 2014

An often overlooked safety feature on your vehicle, the windshield wiper blade is important not only in the rain, but during the freezing Winter months as well.

The History of Windshield Wipers

The first patent for a window cleaning device for electric cars and other vehicles was issued in 1903 to inventor Mary Anderson.  Powered by hand using a lever inside of the vehicle, her design was a popular one found on many cars during that time.  It would take almost 20 years of moving the windshield wiper by hand before an automatic windshield wiper was developed.

John R. Oishei of the Tri-Continental Corporation was the first to introduce the two blade windshield wiper system found on cars today.  His corporation would later evolve into Trico, one of the leading manufacturers of windshield wiper products still to this day.

The patent for an automatic windshield wiper was finally granted to William M. Folberth in 1922 which was disputed by Trico, who claimed that the design was theirs.  This dispute was resolved with Trico purchasing Folberth’s company and incorporating it into his.  The new automatic windshield wiper system was vacuum powered and was quickly adopted as standard equipment by all the major automobile producers of the time.  This system was in use until 1960.

During the 1960’s, many inventors were experimenting with electronic windshield wiper applications, and the ability to incorporate intermittent speeds.  One of the most successful was Robert Kearns, an engineering professor who proposed his idea of an electronic, intermittent windshield wiper system to the Ford Motor Company in 1963.

The Ford Company declined Kearns’ idea but showed up in 1969 with a windshield wiper system on their Mercury line that resembled it very closely.  A patent dispute ensued that went on for years before finally being settled in court.

Today you will find a similar design is standard equipment on all vehicles sold in the U.S.  You will also see them in use on the rear view window and on some luxury cars, the headlights.

Windshield Wiper Parts

There are two main parts working to provide power to the windshield wipers, an electronic motor and a worm gear.  The small motor has its speed enhanced by the worm gear, allowing the wipers to work at full speed.  Not only will the gear increase the torque of the motor fifty times, it can decrease its speed by fifty times as well. This allows you to choose the speed of your wipers.  Also located inside is an electronic sensor that lets the motor know when the wipers are in the down position so that it can shut off.

There is a cam on the output shaft of the worm gear which in turn is connected to a long rod.  As the cam moves, the rod is spun back and forth moving the wiper blades along with it.

Windshield Wiper Blade

The windshield wiper blade mechanism is designed specifically to allow the thin rubber strip it holds to drag across the windshield evenly, and with an exact amount of pressure. 

The wiper blade is designed to attach to the wiper rod at a single point in the middle.  From there, a series of arms branch out so that the blade is actually connected in six or up to eight different places.  This ensures that the pressure is consistent at all times, eliminating a streaking effect.

The rubber strip is designed to act like a squeegee and propel water off of the windshield without any streaks.  It needs to have a tight seal with the glass in order to accomplish this.  As the rubber becomes cracked and brittle, it will lose that function and the drivers view will be obstructed by streaking.

Wiper Blade Design

Most wiper blades work in the tandem system, where one pivot is located at the driver side while the other is centered.  The windshield wiper blades move in unison together and will clear almost the entire windshield with each pass. Other types include:

  • The opposed system, where there is a pivot point at each end of the windshield
  • Controlled single arm is one blade that operates from the center point of the windshield.  The windshield wiper blade is able to expand and contract, clearing away almost all accumulated water.
  • Single arm is also pivoted at the center of the windshield but does not have the ability to extend itself.

Replacing Windshield Wiper Blades

The rubber component of the wiper blades will wear out over time and necessitate changing for optimal visibility.  Snow and ice can also damage the arms of the wiper blade, affecting the pressure points on the windshield.  As a rule, manufacturers suggest changing wiper blades yearly, but this should be done more often if you begin to notice streaking.

Even if the blades themselves appear in good condition, you should always change the complete part, not just the rubber strip and buy blades that are a match for your vehicle. 

To change them, pull the existing blades away from the windshield.  It is a good idea to place a towel over the windshield to protect it in case the blades snap back.  Look for where the blade is attached to the rod and unhook it.  From there you only need to hook the new ones in its place.

Windshield wiper blades have evolved from a very simple mechanism into one that drivers around the world are now dependent on to keep them safe in inclement weather.

Categories: Autowiki Car Systems