TechnicBRICKs: TBs TechNuggets 12 - Inside the Linear Actuator II

September 6, 2013 – 11:09

TBs TechNuggets 12 - Inside the Linear Actuator II

Some days ago,Daniel reported about his newly received 8043 Service Pack and of course the new Linear Actuators coming inside. Those we all expect to definitely solve the issues experienced with the large Technic Excavator.

Daniel was brave enough to destroy one of these ,still rare LAs,and show us what was changed inside in comparison to the old LA.

He tell us they are almost identical in form,the new LA still takes the same number of revolutions to fully extend and still extends to the same length.Also there is still the same internal clutch mechanism.
The white plastic sleeves look identical on both,older and newer LAs,either from the outside as on the inner thread (Daniel cut them in slices to check).

The main difference can be seen in the worm thread at the metallic rod. The 'tooth' profile is noticeable smaller,hence reducing the friction,specially at higher loads.

While there was no grease used within the original LA (at least not in the one I opened about two years ago [1,2 ]),we can see now a lot of it inside the new LA version. Obviously another measure in the attempt to reduce friction.
"Grease has been applied inside the sleeve,inside the clutch and betweenthe orange part and the outer casing. The plastic was also much harderto cut away on the newer LAs (more glue),which is why the two dark greypieces look different in the picture below".

Changes in performance:

  • Lower rattle while extending/retracting the new LA.
  • The new LA is quieter
  • The new LA extends/retracts more smoothly,especially at higher speeds.

Because of the grease used in the clutch,guess the new ones to be less noisy when clutch gets triggered.

On the down-side,because the new LA has a thinner 'tooth',the new LA bends a lot more when fully extended.
According to Daniel's words "The end of the rod can move by an extra mm in each direction. It is notactually as bad as the photo suggests,but is still noticeable".

Now it rests to see if how these modifications turn to be effective in solving the 8043 issues and how durable they are.
Lets see also if the extra rod bending,doesn't turn into a limitation or a weak point,for some applications.

Courtesy photos from Daniel.
Thanks for sacrificing your LAs,to show us the difference.


BISS (Honeywell, Inc.)
  • Honeywell Product 43916-548

40 corrections per second

2007-12-06 12:27:37 by iamlucky13

What they mean when they say that, is that the computer reads the input states 40 times per second. Each time it reads the input states, it compares the values to expected values, then uses an algorithm to determine the desired control states. We now have computers with processing power to do it hundreds of thousands of times per second...much much faster than the response times of the systems involved and sometimes faster than any actuators can actually respond.
The algorithms are engineered from known factors like lift, drag, center of gravity, etc. Then some poor schmuck of a test pilot takes the plane up and determines if the engineers got it right or if it needs a little tweaking (hopefully not a lot of tweaking)

Fieldbus for steam-drain control  — InTech
Ultimately, when you minimize signals, you improve the overall efficiency and performance of the network.

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