Saturday, 21 September 2013

Rearming - Part 2

Nothing is particularly easy......

Having reassembled the arm, I soon discovered a serious problem...  The forearm and shoulder joints was completely jammed solid after a couple of turns on the motor pulleys.   It was not until the next day, I could see exactly what the problem was....  The reduction gears had been catching on the motor bolts.

I actually remember swapping these around the other month back to keep consistent with the blueprints:


However, reading the manual, it's clearly printed in black & white "The bolts which are next to the reduction gears should be placed nut out to prevent the reduction gears catching on the end of the bolts."

The blueprints are wrong -  I've been finding plenty of mistakes with this drawings!

So, I had to once again, remove the arm, sensors, timing belts, reduction gearing, swap these bolts around, and start all over again....   hopefully, second time lucky....

Nut & Bolt swapped around as per the instructions :

Start of reassembly...

The reduction gearing was re-installed, and all moving parts lubricated with one of these precision oiler pens:

This time, I double checked every motor turned without any problems before lowering the arm into position.   I have slight play on the shoulder gearing which I suspect is a consequence of the hairline fracture.

Having then reassembled the rest of the Arm, I noticed from the exploded diagrams I'm missing a couple of washers - part number 120.  I really can't face taking this apart again, so I'm going to leave for now....

Gripper cable reattached to the tension spring mounted on the Shoulder Pan.

I also have been checking tension of all cables - left hand side wrist was loose, so a good pull with a pair of pliers and re-tightened grub screws did the trick!   Also cut away excess string leaving roughly 1cm in all cases for future adjustments.

Here are a few pictures of the Armdroid now :-

It's really exciting to see things coming together !

As you can see, just need to reinstall the reed switch sensors, and cable tie all cables back into position.

Turning all motors by hand, all joints appear to be behaving themselves, a little more lubrication will be applied, and hopefully, that completes the mechanics.