Parking and emergency brake operating mechanism for dual mode drum brake assemlby

A drum brake assembly having a leading/trailing service brake and a duo-servo parking and emergency brake and adapted to selectively frictionally engage a brake drum comprising:

• a backing plate adapted to secure the drum brake assembly to a vehicle component;
• first and second brake shoes supported relative to said backing plate;
• a service brake mechanism supported relative to said backing plate and disposed between a first pair of adjacent ends of said brake shoes, said service brake mechanism adapted to selectively move said brake shoes into frictional engagement with the brake drum;
• a rotation preventing abutment supported relative to said backing plate, said rotation preventing abutment disposed between and engageable with a second pair of adjacent ends of said brake shoes opposite said first pair of adjacent ends;
• a pivot lever pivotally supported relative to said first brake shoe and operatively coupled to exert an outward force on said first brake shoe when the parking and emergency brake is actuated;
• a first strut supported relative to said backing plate, said first strut including a first end coupled to said second brake shoe and a second end coupled to one end of said pivot lever;
• a second strut disposed adjacent said rotation preventing abutment and including a first end coupled to said second brake shoe and a second end coupled to an opposite end of said pivot lever, said second strut having a long dimension and a short dimension and including an upper link and a lower link, said upper and lower links having sections which are spaced apart from one another to define a cavity within said second strut;
• parking and emergency brake actuating means supported relative to said backing plate and operatively coupled to said actuation cable for mechanically actuating said pivot lever to urge said first brake shoe outwardly into engagement with the brake drum and thereby initiate duo-servo actuation of the parking and emergency brake through one of said first and second struts, said parking and emergency brake actuating means including an actuating lever having a long dimension and a short dimension and pivotally supported relative to said second strut, said long dimension of said actuating lever disposed substantially within the confines of said second strut cavity and said long dimension of said actuating lever extending in the same direction as said long dimension of said second strut wherein said actuating lever is a composite actuating lever comprised of an upper link and a lower link adjacent ends of which are joined at one end and define an actuating lever cavity therebetween at an opposite end thereof, said cavity actuating lever cavity including a first opening and a second opening which is smaller than said first opening;
• and
• an actuation cable having an end portion operatively connected to said actuating lever in a generally perpendicular relationship relative to said backing plate.