Patent ID: 6695100
Filing Date: 2004-02-24
Classification: F16D

Abstract:
A drum brake for a vehicle wherein first and second brake shoes are positioned on a backing plate that is secured to the vehicle and radially aligned with a drum, said first and second brake shoes each having a first end that is aligned with an anchor post that extends from the backing plate and an actuator member and a second end that is linked to each other by an adjuster mechanism, said first end of said first brake shoe and said first end of said second brake shoe being selectively spaced apart from each other by said actuator member; resilient means connected to said first and second brake shoes for urging said first ends toward said anchor and said second ends toward said adjuster mechanism to define a rest position for said first and second brake shoes wherein a running clearance is established between friction surfaces on said first and second brake shoes and a braking surface on said drum, and an input member connected to said actuator member for transmitting a force that moves said first and second brake shoes through said running clearance such that said friction surfaces contact said engagement surface of said drum to effect a brake application, said resilient means being characterized by a first spring with a first helical coil located between a first end of a first engagement section and a first end of a second engagement section, a second helical coil that extends from said first end of said first engagement section to a second end and a third helical coil that extends from said first end of said second engagement section to a second end, said second end of said first engagement section and said second end of said second engagement section being connected to said backing plate such that said first and second engagement sections contact said first and second brake shoes and said second and third helical coils to urge said first and second brake shoes toward said backing plate while said first helical coil urges said first and second brake shoes toward said actuator and adjuster to define said rest position, said first helical coil having a different spring force than said second and third helical coils such that a greater force is required to move the first and second shoes toward said drum than is required to move the first and second shoes toward said backing plate, and second end of said first engagement section and said second end of said second engagement section each being defined by a hook that engages said backing plate to retain said first helical coil in a desired location on said backing plate.