US Patent 7748288 Gear-driven balance shaft apparatus with backlash control

An apparatus for controlling backlash comprising an intermediate gear capable of adjustably meshed engagement between a first driving gear and a second driven gear, and a body rotatably supporting the intermediate gear and capable of movement in a direction that reduces the center distance between the intermediate gear and either the first gear, the second gear, or both. The movement of the body utilizes both resilient urging and hysteretic damping to supply appropriately light resilient biasing while being fortified against rapid retraction or repulsion.