The wagons they used could steer, and the link connecting the front wheels together were a primitive tie-rod with metal ends now called ball joints. Their links in place of ball joints must have been an L shaped bit of metal with either a pin or ring, this side obviously having the pin. The long pointed end would fit inside a drilled out tie-rod made of heavy wood and clamped to keep the L shaped tie-rod from slipping out.
Thats only a guess, and even 200 years I would think they could have incorporated bolts instead of a tapered shaft but I don't really know. Its possible this design allowed easier 'in field' repairs without using bolts. Still doubtful because it required a drilled out tie-rod to fit into, requiring more work than a couple bolts.