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.
http://i.cubeupload.com/eXICt7.jpg

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.
http://i.cubeupload.com/54UwZW.jpg

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.
http://i.cubeupload.com/pSB77I.jpg
http://i.cubeupload.com/8lgaVh.jpg

My problem, right now, is just *understanding* the patent description:
https://www.google.com/patents/US4907468
http://i.cubeupload.com/wYA3iD.jpg

"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."
http://i.cubeupload.com/gMfTU7.jpg

Given they talk about both a two-spring and one-spring setup:
http://i.cubeupload.com/wYA3iD.jpg

But our setup is clearly just one spring:
http://i.cubeupload.com/WYoC8J.jpg

what specifically do you think they mean by "urging" and "treading"?
http://i.cubeupload.com/2Bsddp.gif

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.
http://i.cubeupload.com/eXICt7.jpg

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.
http://i.cubeupload.com/54UwZW.jpg

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.
http://i.cubeupload.com/pSB77I.jpg
http://i.cubeupload.com/8lgaVh.jpg

My problem, right now, is just *understanding* the patent description:
https://www.google.com/patents/US4907468
http://i.cubeupload.com/wYA3iD.jpg

"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."
http://i.cubeupload.com/gMfTU7.jpg

Given they talk about both a two-spring and one-spring setup:
http://i.cubeupload.com/wYA3iD.jpg

But our setup is clearly just one spring:
http://i.cubeupload.com/WYoC8J.jpg

what specifically do you think they mean by "urging" and "treading"?
http://i.cubeupload.com/2Bsddp.gif

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.
http://i.cubeupload.com/62kbRS.jpg

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.
http://i.cubeupload.com/eXICt7.jpg

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.
http://i.cubeupload.com/WO7trl.jpg

We've also redesigned the P and Q bushings, using better materials:
http://i.cubeupload.com/UMY0Vl.jpg

But they still fail within two or three years.
http://i.cubeupload.com/UnuX55.jpg

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.
http://i.cubeupload.com/Y18Qdh.jpg

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:
http://i.cubeupload.com/TYHGRW.jpg

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.
http://i.cubeupload.com/wYA3iD.jpg

But is that the case?

We don't know, simply because we don't understand the language of the
patent. https://www.google.com/patents/US4907468

Do you?

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

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

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

The "treading force" is the pressure exerted on the pedal,
and "urging the pedal" means operating it.

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:
http://i.cubeupload.com/2Bsddp.gif

Here is the patent diagram (which is almost exactly the same):
http://i.cubeupload.com/wYA3iD.jpg

While some of us have re-engineered the bushings, the bushings still fail:
http://i.cubeupload.com/8lgaVh.jpg

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:
http://i.cubeupload.com/pSB77I.jpg

We've spent some effort on finding just the right geometries for that
linear spring:
http://i.cubeupload.com/FaKA4k.jpg

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!).
http://i.cubeupload.com/WO7trl.jpg

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:
https://www.google.com/patents/US4907468

"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?

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?)

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

On Sun, 25 Dec 2016 18:44:58 +0000 (UTC),
Frank Baron wrote:
What does "urging" the clutch pedal mean?
(And what is this "treading" force?)

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?

--
Ted Heise Bloomington, IN, USA

On Sun, 25 Dec 2016 22:43:18 +0000 (UTC), Theodore Heise
wrote:

On Sun, 25 Dec 2016 18:44:58 +0000 (UTC),
Frank Baron wrote:
What does "urging" the clutch pedal mean?
(And what is this "treading" force?)

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

Theodore Heise said:

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

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.

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?

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.

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

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

I think that's what the urging may imply!