GM Files To Patent Extendable Windshield Wiper Arms4
GM has filed a patent application for an extendable windshield wiper blade design that could potentially provide greater wiper blade coverage on vehicles of all types.
This GM patent filing has been assigned application number US 11,345,317 B2 with the United States Patent and Trademark Office (USPTO) and was published on May 31st, 2022. It’s titled “Extendable Windshield Wiper System” and lists Michigan engineer Bruce N. Greve, James C. O’Kane and David T. Renke as the inventors.
The patent filing describes a wiper blade design with a bored wiper sleeve that has a “wiper extension rod slidably disposed within the bore.” The wiper would also feature an actuator that could direct pressurized fluid to outwardly extend the wiper extension during the initial phase of the wiper’s arc rotation, allowing the blade to extend into the upper portions of the windshield without being inappropriately long when not in use. As the patent says, “wiper systems incorporating a fixed-length wiper blade having a fixed arm length wiper swing cannot clear a sufficient surface area of the windshield.” This design would, in theory, address this problem.
Automakers have been attempting to address the problem of windshield wiper blade coverage for quite some time, it seems. Mercedes-Benz offered a similar technology called ‘Mono Wiper‘ on the first-generation E-Class, which hit the market back in 1987. This tech was a little more simplistic (though impressively effective), using a sun gear to turn a small crank that extended and retracted the sedan’s large single wiper arm throughout the arc phase. The design also enabled Mercedes engineers to use just a single wiper blade for the sedan’s windshield, reducing its aerodynamic drag and improving fuel efficiency.
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They can’t even get automatic wipers that work properly and now they want extending wipers?
I went to the USPTO web site and searched the patent gazette for May 31, 2022 to read the full text of this patent
The first observation is that this scheme would probably not work well in any climate with icy winter conditions where to slide mechanism will almost certainly jam up due to ice. A relief valve could be provided to allow excess fluid pressure to bypass in the event of a slide jam, allowing the wiper arms to continue moving.
The second observation is that Rube Goldberg would love this overly complex solution. The same result might be obtained with a similar slide mechanism (see above problem) and unequal length bell cranks or a simple gear and eccentric cam to drive the slide. However, the simple mechanical coupling might be inoperable in icing conditions.
The third observation is that this problem already has a solution using beam type wipers with overlapping paths driven out of phase from opposite sides of the windshield. I have this on the GM car (Bolt EV) which I drive right now. The only way the complex fluid system makes sense is if it is less expensive than a second motor required in the current GM system.
Inappropriately long when not in use??? That’s what she said….
Mercedes did this in the 90’s, and I doubt this was a new idea then.