Stokes weight-relieving bogie, with ball on upper arm to engage with socket, and lower arm connected by cross pin.
Cowans Sheldon 50 ton breakdown crane MP4 (1930)
RichardAsh1981
CC BY-SA 2.0
<a rel="nofollow" class="external free" href="https://www.flickr.com/photos/30661871@N03/49819142097/">https://www.flickr.com/photos/30661871@N03/49819142097/</a>