Abstract: A fast-acting valve includes an annular valve seat that defines an annular valve orifice between the edges of the annular valve seat, an annular valve plug sized to cover the valve orifice when the valve is closed, and a valve-plug holder for moving the annular valve plug on and off the annular valve seat. The use of an annular orifice reduces the characteristic distance between the edges of the valve seat. Rather than this distance being equal to the diameter of the orifice, as it is for a conventional circular orifice, the characteristic distance equals the distance between the inner and outer radii (for a circular annulus). The reduced characteristic distance greatly reduces the gap required between the annular valve plug and the annular valve seat for the valve to be fully open, thereby greatly reducing the required stroke and corresponding speed and acceleration of the annular valve plug.

Abstract: A bone core removing tool with a stainless steel cylinder having an internal bore extending along the cylindrical axis from an externally honed cutting edge for cutting a core of bone which is pushed into the bore as the tool is driven into a bone and a plurality of radially inwardly extending teeth within the bone adjacent the edge for preventing rotation of the core to permit removal of the core by rotating the tool to break the core at the cutting edge.