US Patent 7675216 Brush spring retainers

Brush spring assemblies for heavy-duty use are addressed. Such assemblies may include constant-force springs used to bias carbon brushes into contact with commutator surfaces. They additionally may include temporary capture mechanisms for the springs, allowing the springs to be retracted—and retained in a retracted position—while brackets containing the springs are inserted into brush holders. Post insertion, the capture mechanisms may be manipulated so as to release the springs, permitting the springs thereafter to bias brushes toward the commutator surfaces.