On Sun, 25 Dec 2016 18:44:58 +0000 (UTC), Frank Baron advised:
What does "urging" the clutch pedal mean?
> (And what is this "treading" force?)
>
> Everyone with a Toyota-4Runner 3rd-generation manual transmission and
> similar Toyota Tundras and Toyota Tacomas has a problem that a certain tiny
> plastic bushing invariably fails within a year or three in the clutch pedal
> double-helix torsion spring return apparatus.
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> The "repair" costs upwards of $150 for parts alone, simply because the
> clutch pedal bracket assembly and the pedal itself are usually toast, even
> though the three tiny P & Q bushings costs only five bucks each and the
> spring itself is only about double that.
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> We have already redesigned the clutch pedal return assembly but what we're
> now trying to figure out is WHY Toyota used such a complex torsion spring
> mechanism when our redesigned linear tension spring seems to work fine.
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> My problem, right now, is just *understanding* the patent description:
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> "The present invention relates to an apparatus for reducing the treading
> force required to operate a pedal, such as the clutch pedal of an
> automobile. More specifically, the present invention relates to an
> improvement of the means for urging the pedal."
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> Given they talk about both a two-spring and one-spring setup:
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> But our setup is clearly just one spring:
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> what specifically do you think they mean by "urging" and "treading"?
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Restating the question to ask if anyone here can tell us what the patent says about the single-torsion spring setup...
The problem everyone with a clutch has on 3rd-generation Toyota 4Runners, Tacomas, and Tundras is that the Toyota dealer seems blissfully unaware of the clutch pedal squeak root cause during the warranty period.
So the dealers simply grease the $5 nylon P bushing and delron Q bushings, but by the time the squeak occurs, the $100 clutch pedal P-tab groove is already starting to be destroyed, eventually taking with it the $100 clutch pedal bracket holding the two $5 Q bushings.
So most of us have redesigned the Toyota clutch-pedal return assembly to remove the extremely complex (geometrically) torsion spring and replace it with a far simple linear spring setup.
We've also redesigned the P and Q bushings, using better materials:
But they still fail within two or three years.
We're currently at the stage of trying to *understand* why Toyota engineers used such a horrifically complex clutch-pedal-return mechanism, which we need to know if we're going to assess the long-term impact of our redesign.
We only recently found the patent, which shows a mechanism almost exactly the same as ours, so, at this point, we're just trying to understand the patent wording with respect to the single-spring function because we have been re-designing the single spring setup using a variety of methods:
The reason it matters is that the patent shows both a two-spring and a single-spring mechanism, where we presume the two-spring mechanism operates in both directions while we can intuit that the single-spring mechanism operates only in one direction.
But is that the case?
We don't know, simply because we don't understand the language of the patent.
Do you?
Specifically, what is the patent saying the single-spring apparatus accomplishes?