Abstract: A hammer mill has a plurality of hammer assemblies pivotally mounted about the periphery of a rotating rotor. Each hammer assembly has an arm portion connected to a pivot shaft and carrying a detachable head with slightly inclined impact surface. An equalization mass is attached to a rear side of the arm portion with its center of gravity rearwardly of a line between the center of gravity of the entire hammer assembly and the pivot shaft. As the material of the hammer wears away, the center of gravity of the assembly moves rearwardly, pivoting the hammer head forwardly under the centrifugal forces imposed. The wearing life of the head is increased and an optimum impact angle is maintained by the equalization weight. The head is made detachable from the arm but is positively locked during operation.

Abstract: A releasable lock for a wearable device such as a hammer tooth or chain shackle in which two parts of the device are held together by means of a pin, the pin further being immobilized by a deformable rivet, the rivet extending through a transverse bore in the pin.

Abstract: A two-piece hammer for a shredder has a separate hammer face and a separate hammer peen. The face and peen are complementary and have interlocking surfaces so that they may be mounted on a hammer disc or rotor by a single hammer pin to form a unitary hammer which allows the hammer face to be replaced when worn and the peen to be reused.

Abstract: An elongated bar body has two opposite side faces each provided with a longitudinally extending rib. The ribs are offset from the longitudinal midline of the respective side faces in opposite directions and due to this offsetting each of the side faces has a larger and a smaller face portion. The larger face portions of the side faces overlap one another partially in transverse direction.