Two stage centerless grinders

A two stage centerless grinder comprising:

• a pair of grinding wheels each rotatably journaled on a base,
• electric motor means for individually and separately rotating each of said grinding wheels,
• a pair of regulating wheels, each rotatably journaled on said base with one disposed relative to each of said grinding wheels so as to form between each pair of grinding wheels and its associated regulating wheel an inlet end and an outlet end,
• a work support located between each pair of grinding wheels and associated regulating wheel adapted to support a workpiece of revolution,
• said work support comprising a thin blade forming substantially a horizontally positioned edge for supporting the workpiece, and
• a first means for adjustably mounting said blade for vertical movement for positioning a workpiece resting on said edge in a selected position relative to the axis of rotation of said regulating wheels,
• said first means comprising a pair of wedges mounted in the same plane one slidable along an edge of the other for moving said blade relative to an associated grinding wheel and regulating wheel for varying the position of the workpiece,
• a second means for pivoting each of said regulating wheels relative to its associated grinding wheel, and
• a third means for axially moving a workpiece relative to said first grinding wheel and said first regulating wheel for a first grinding effort and sequentially moving said workpiece relative to said second grinding wheel and said second regulating wheel for a second grinding effort,
• said third means comprising a venturi tube means for feeding the workpieces sequentially to said inlet end of each stage and out of said outlet end of each stage,
• the first stage comprising a single, relatively wide grinding wheel, and
• the second stage comprising two or more individually narrow width grinding wheels which are bonded together to gradually decrease the coarseness of the cutting abrasive.