Power feed mechanism for a three-dimensional printer

A powder feed mechanism for transporting powdered build material from a powder chamber to a material bed of a three dimensional printer, the powder feed mechanism comprising:

• a carrier arm arranged to move through the powder chamber between a powder capture position and a powder delivery position;
• and
• a support platform having a powder support surface for carrying a heap of powdered build material, the support platform being attached to the carrier arm to move therewith along a path through the powder chamber as the carrier arm moves between the powder capture position and a powder delivery position,
• wherein, when the carrier arm is in the powder delivery position, the powder support surface of the support platform is in a transverse orientation for lying flush with the material bed, and
• wherein the carrier arm is pivotably mounted over the powder chamber to swing back and forth through the powder container during upstroke and downstroke movements, whereby the support platform moves in an arc-shaped path through the powder chamber.