Am Montag, 9. Oktober 2017 15:15:55 UTC+2 schrieb Larry Jaques:

https://www.flickr.com/photos/138493...posted-public/
https://www.flickr.com/photos/138493...posted-public/

Fascinating that the part has 3 weld tails and no (visible) welding on
the bottom left side. Those tabs are under extremely high pressure as
pivot points. Historical failure surely led to this practice. I'll
bet Caterpillar, Kubota, Case, Hitachi, Komatsu, Volvo, etc. engineers
have some stories to tell about them. If you write to them and they
respond, please share it with us. I always got Gibbs-slapped as a kid
because I constantly asked for more details about everything.

Those are JCB loader pivots. Interesting thing is, the early pivot plates did not use this arrangement of welds (instead they were welded all the way around and had no central hole) and they did not regularly fail. However, the early pivot plates were about twice as big and heavy. I figure it's an optimisation process which demands this kind of weld design.

Might write to them if I have time. Not sure that will happen though. The JCB Facebook group would be quicker for an informal answer.

Best wishes,

Chris