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