Disc wheels, i.e. wheels with load-supporting disc body: with a single disc

Official title: with a single disc body not integral with rim {, i.e. disc body and rim being manufactured independently and then permanently attached to each other in a second step, e.g. by welding}

B60B3/04 (Disc wheels, i.e. wheels with load-supporting disc body: with a single disc) appears on 284 US grants and 293 published applications in this corpus.