Hi Stu,
Yeah, the rod-ends allow the cradle to move freely. The rose joint, called a heim over here, on the frame is a standard item. They have a wide range of motion. The one on the cradle is called an 'elastomeric" rod-end from Lords. They do everything a regular rod-end does but they are rubber so they have some cushion. This one is rated to deflect in tension or compression 20thou at 250lbs, it's a trade off against using a straight heim on both ends. It wasn't a comfort issue, I was afraid of breaking the frame. That's why there's a tube to spread the load to both sides.