Workpiece-centering two-sided planer

An apparatus for planing opposite sides of a workpiece, the apparatus comprising:

• a housing having a lower part and an upper part flanking a passage through which the workpiece to be planed is passed horizontally in a travel direction;
• respective upper and lower planing drums rotatable on the respective housing parts above and below the passage about respective upper and lower axes extending transverse to the direction and defining on such rotation respective upper and lower cutting orbits centered on the respective axes, the lower drum being upstream of the upper drum relative to the workpiece travel direction, the lower drum being upstream relative to the travel direction from the upper drum;
• a stationary workpiece support table between the drums and having a planar upper surface level and tangent with the lower orbit, whereby the lower side of a workpiece passed in the direction over the lower drum is planed and slides downstream of the lower drum on the table surface;
• respective upper and lower guide plates having vertically confronting faces upstream of the lower drum and being vertically displaceable on the respective housing parts between inner positions with the upper-plate face and lower-plate face level and tangent with the respective orbits and outer positions respectively vertically thereabove and therebelow;
• link means interconnecting the upper and lower plates for substantially synchronously and oppositely displacing the plates so that same are always equispaced from a horizontal plane extending horizontally in the direction and vertically equispaced from the upper and lower orbits;
• biasing means connected to the plates for urging the plates into the inner positions;
• and
• respective upper and lower transport means each comprising
• a plurality of downstream wheels immediately adjacent the respective plate, respective upstream wheels upstream from the downstream wheels and vertically offset therefrom away from the passage, and respective endless traction elements spanned between the wheels and having respective stretches exposed in the passage, the stretches forming respective upper and lower confronting workpiece gripping surfaces immediately upstream of the respective plate faces and advanceable in the travel direction for feeding the workpiece between the plates, the transport surfaces converging in the travel direction and having extreme downstream portions generally level with the respective plate faces.