Adjusting device for activating brake shoes

Claim 1

An automatic adjusting device for automatically adjusting vehicle brakes of the type including a drum, a pair of shoes having lining thereon and moveable against a biasing force into braking contact with said drum, a camshaft having a cam thereon and mounted such that rotation of said camshaft causes said cam to move said shoes into contact with said drum, and a braking drive device operatively connected to said cam shaft for selectively caUsing rotation thereof; said automatic adjusting device comprising: at least one ratchet wheel rigidly mounted on said cam shaft; an activating lever freely rotatably mounted at a first end thereof about said cam shaft and connected at a second end thereof to said braking drive device; at least one first ratchet cog mounted on said activating lever and radially biased into engagement with teeth of said at least one ratchet wheel, said first ratchet cog comprising means for rotating said ratchet wheel and said camshaft when said activating lever is moved by said braking drive device; a rocking lever mounted for rotation, adjacent the periphery of said ratchet wheel, about an axis parallel to the axis of said camshaft; at least one second ratchet cog mounted on said rocking lever and radially biased into engagement with teeth of said ratchet wheel at a position diametrically opposite said first ratchet cog, rotation of said ratchet wheel causing rotation of said rocking lever; first abutment element means on a first side of said rocking lever for limiting the extent of rotation of said rocking lever in a first direction; second abutment element means on a second side of said rocking lever for limiting the extent of rotation of said rocking lever in a second direction; and adjustment means for adjusting the position of at least said second abutment element means.