US Patent 7175236 Hammer for breaking concrete

The hammer impact cracks the concrete, then separates the concrete from the steel and creates concrete aggregate. The hammer has a pair of arms with an angled portion for sliding on an angled portion of guide plates, which have a long surface in contact with the hammer arms to provide a stable movement of the hammer without sideways motions. The hammer can be a gravity drop hammer or a compressed gas accelerated hammer. The hammer can pivot to adjust the blows to be perpendicular to the surface being impacted. The pivot also helps in retracting the hammer from the concrete to unjam it therefrom particularly when the concrete is moving relative to the hammer. The pivotable hammer is useful for transporting the hammer and for maintenance work on the hammer. The hammer has teeth to increase the shock of impact to crack and then break the concrete along the cracks.