Drum brake system with two tension springs

A drum brake system, comprising a back plate assembly and a brake drum (1) that is rotatable with respect to the back plate assembly,

• the back plate assembly comprising:
• a back plate (2);
• two brake shoes (3, 3′), the two brake shoes (3, 3′) being pivotably connected to the back plate (2), pivot axes (4, 4′) of the brake shoes (3, 3′) being disposed at positions adjacent to first ends of the brake shoes (3, 3′);
• an actuator housing (5) with two pistons (6, 6′), the two pistons (6, 6′) being configured to move outwardly, to press each piston (6, 6′) against one of the brake shoes (3, 3′) to pivot the respective brake shoe (3, 3′) outwardly about its respective pivot axis (4, 4′), and to press the respective brake shoe (3, 3′) against the brake drum (1) for braking;
• a return spring (7) extending between the brake shoes (3, 3′) and being connected to both brake shoes (3, 3′), the return spring (7) being configured to exert a retracting spring force that pulls both brake shoes (3, 3′) away from the brake drum (1);
• a pair of tension springs (8, 8′) comprising a first tension spring (8) and a second tension spring (8′), and a holder arrangement (9), inner ends of the first tension springs and the second tension spring (8′) being connected to the holder arrangement (9), an outer end of the first tension spring (8) being connected to a first brake shoe (3), and an outer end of the second tension spring (8′) being connected to a second brake shoe (3′),
• wherein the holder arrangement (9) is connected to the actuator housing (5) and,
• wherein the holder arrangement (9) comprises a movable holder for the first tension spring (8) and for the second tension spring (8′) for adjusting pre-tension conditions of the first tension spring (8) and the second tension spring (8′).