What does "urging" a clutch pedal mean versus what is a "treading" force?

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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Reply to
Frank Baron
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On Sun, 25 Dec 2016 18:44:58 +0000 (UTC), Frank Baron advised:

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.

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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.

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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.

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We've also redesigned the P and Q bushings, using better materials:

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But they still fail within two or three years.

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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.

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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:

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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.

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But is that the case?

We don't know, simply because we don't understand the language of the patent.

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Do you?

Specifically, what is the patent saying the single-spring apparatus accomplishes?

Reply to
Frank Baron

On Sun, 25 Dec 2016 19:19:15 +0000 (UTC), Frank Baron advised:

I wasn't sure if the terms were "directional" since what we're trying to figure out is why Toyota uses this method, and what the difference is in the patent description for the two spring method (which we don't have in our vehicles) and the one spring method (which is what we have).

Since our vehicle diagrams look almost exactly like those in the patent, we think the rationale as to WHY Toyota used such a complex mechanism will be described in the patent (if we only understood what the patent says).

Here is our vehicle diagram:

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Here is the patent diagram (which is almost exactly the same):

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While some of us have re-engineered the bushings, the bushings still fail:

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Given the re-engineered bushings still fail, most of us have simply dispensed with the torsion spring altogether, replacing it with a linear spring instead:

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We've spent some effort on finding just the right geometries for that linear spring:

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But, we're really shooting blind if we don't know WHY Toyota used such a complex torsion spring setup when we know they knew all about the linear springs (since all the attachment points already exist!).

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Given what you've said, which is that "urging" is merely operating the pedal, and "treading" is the force applied, then we can convert this quote:

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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."

To this quote: "The present invention relates to an apparatus for reducing the /amount of/ 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 /operating/ the pedal [initially]."

It's important to get the interpretation correct because the pedal has multiple modes of travel, from the initial pressure to the ending release to the various points in the arc in between (which the patent discusses in similarly cryptic engineering terms).

In summary, it seems that the patent mostly refers to the purpose in being to alleviate STARTING (urging) force - would you concur?

Reply to
Frank Baron

On Sun, 25 Dec 2016 18:44:58 +0000 (UTC), Frank Baron advised:

Please ignore this thread in favor of the update which is more clearly stated.

Reply to
Frank Baron

As others have suggested, I beelieve the treading force is the force applied by the foot to depress the clutch pedal.

I wonder if "urging the clutch pedal" may refer to the process of releasing it gradually (after first being depressed) by reducing the treading force until the transmission begins to be engaged and the clutch pedal can be released entirely?

Reply to
Theodore Heise

AKA "slipping" the clutch - or if too much power is applied, "smoking" it.

Reply to
clare

I think that's right as in "don't tread on me".

The urging, I'm thinking, is the *beginning* of the pedal travel; but I'm not at all positive that's what "urging" means.

After reading the patent a dozen times (not understanding it yet, completely), I think "urging" may be either what you say, which is the beginning of the release cycle, or, what I'm leaning toward (but I'm not sure) which is the beginning of the depression cycle.

It's got something to do with momentum it seems.

Reply to
Hazuki Nakamura

On Mon, 26 Dec 2016 01:23:12 +0000 (UTC), Hazuki Nakamura advised:

I think that's what the urging may imply!

Reply to
Frank Baron

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