Automatic brake slack adjuster

Claim 1

In an automatic brake adjuster interposed between a brake operating shaft and a brake operating rod, the brake adjuster including a body having slack adjustment means defined therein including an adjustment shaft having a worm fixed thereon meshing with a brake operating shaft actuator and a gear concentrically rotatably fixed to the adjustment shaft for rotating the same; the gear being selectively driven by an operating worm operatively connected to the brake operating rod, the improvement comprising key means defined on the adjustment shaft keying the gear thereto, said key means permitting axial slidable displacement of the gear upon the adjustment shaft between engaged and disengaged positions relative to the operating worm, spring means biasing the gear toward said operating worm engaged position and gear retaining means defined on the adjustment shaft aligning the gear with the operating worm at said engaged position, the gear being axially displaceable on the adjustment shaft against the spring biasing force to shift the gear to said disengaged position, said key means comprising a non-circular wrench engaging portion defined on the adjustment shaft, the gear having an accessible socket of a configuration complementary to said wrench engaging portion whereby displacement of the gear to said disengaged position exposes said wrench engaging portion for engagement by a wrench to rotate the adjustment shaft.