@ 'Blakbird'
- The U-joint going to the linear actuator for the bucket (the one furthest out the arm) is operating at an extreme angle, almost 45 degrees. This will make it pretty inefficient but I assume LEGO has done the testing to make sure it won't bind. The output speed will be non-linear (jerky), but if it is slow enough you may not notice.
I rebuild the arm and you are right, unless I do a bit more finetuning, the movement is, well as you noted, a bit jerky.
- The use of U-joints to send torque up the arm from motors in the chassis rather than having smaller motors located at the point of load means that there will be LOTS of U-joints. Every articulation point of the arm has to have a corresponding U-joint for each function passing that axis.
There are a total of 8 U-Jointup the arm! Has there been any set with more? Well it is an equalizer, sets with 8 x 4L U-joints do exist! The routing of the axles to drive the LAs is great.
in my BS Folder
arm contracted
arm extended
fW