Concrete slab extruder having a free flight auger

Claim 2

A machine for forming hollow cored articles, comprising: a frame; at least one rotatable auger of open spiral configuration having an internal surface conforming to an envelope produced by a surface of revolution; means supporting the at least one auger for rotation about its central longitudinal axis in a stationary position relative to the frame; a power source mounted on the frame for rotating the at least one auger; an initial non-rotatable core forming member associated with the at least one auger and having a predetermined cross section with an outer surface conforming substantially to the internal surface of the rotatable auger and having a major portion encompassed thereby; a final core forming trowel member secured in axial alignment to the initial core forming member and establishing the final cross sectional configuration of the core; means surrounding at least the final trowel member to establish the outer surfaces of the article being formed; feed chamber means surrounding said rotatable auger for confining said material whereby the auger moves the material toward the final trowel member and means surrounding the latter member; and means mounting the initial core forming member and final trowel member on the frame.

Claim 3

A machine as described in claim 1, wherein the at least one rotatable auger of open spiral configuration has an external surface defined by a cylindrical envelope having a diameter substantially equal to the largest diameter of the final core forming member.

Claim 4

The machine as described in claim 1, wherein the final trowel member has a cross section that is other than circular.

Claim 5

A machine for forming hollow cored concrete slabs on a longitudinally extending surface, said machine comprising: a main frame having a power source, longitudinal side members and cross support members wherein said main frame further comprises wheel means adapted to engage tracks disposed longitudinally on both sides of said surface; a hopper in communication with a feed chamber and disposed on the frame; a plurality of spaced parallel auger assemblies each having (1) a rotatable auger of open spiral configuration having an internal surface conforming to an envelope produced by a surface of revolution, (2) means supporting the auger for rotation about its central longitudinal axis in a stationary position relative to the frame, (3) an initial non-rotatable core forming member associated with the auger and having a predetermined cross section with an outer surface conforming substantially to the internal surface of the auger and having a major portion encompassed thereby, and (4) a final non-rotatable core forming trowel member secured in axial alignment to the initial core forming member and establishing the final cross sectional configuration of the core; a core forming area defined by top, side and bottom members mounted on said frame, the core forming area surrounding said rotatable augers for confining the molding material while each auger moves the material over its final core forming trowel member, each of the auger assemblies having the rotatable auger operatively connected to the power source.

Claim 6

A machine for forming hollow cored concrete slabs on a longitudinally extending surface, said machine comprising: a main frame having a power source, longitudinal side members and cross support members wherein said main frame further comprises wheel means adapted to engage tracks disposed longitudinally on both sides of said surface; a hopper in communication with a feed chamber and disposed on the frame; a plurality of spaced parallel auger assemblies each having (1) a rotatable auger of open spiral configuration having an internal surface conforming to an envelope produced by a surface of revolution, (2) means supporting the auger for rotation about its central longitudinal axis in a stationary position relative to the frame, (3) an initial non-rotatable core forming member associated with the auger and having a predetermined cross section with an outer surface conforming substantially to the internal surface of the auger and having a major portion encompassed thereby, and (4) a final non-rotatable core forming trowel member secured in axial alignment to the initial core forming member and establishing the final cross sectional configuration of the core; a core forming area defined by top, side and bottom members mounted on said frame, the core forming area surrounding said rotatable augers for confining the molding material while each auger moves the material over its final core forming trowel member, each of the auger assemblies having the rotatable auger operatively connected to the power source.

Claim 7

A machine as described in claim 4 including: a first vibrating means located internally of the initial forming member for causing vibration of the initial forming member to aid in the packing of the concrete to form the concrete slab.

Claim 8

A machine as described in claim 5, including: a second vibrating means operatively connected to a vibrating hammer plate means, the hammer plate means and second vibrating means being disposed at least partially above the first vibrating means and adapted to coact with the first vibrating means to compress and displace the concrete around the initial forming member and the final trowel member so that the finished slab has longitudinal internal voids having a cross sectional shape similar to that of the final trowel member.

Claim 9

A machine as described in claim 6 including: protruding means secured to side members of the core forming area, to form a continuous groove along each outside longitudinal edge of the slab being formed.

Claim 10

A machine as described in claim 4 wherein each rotatable auger of open spiral configuration has an external surface defined by a cylindrical envelope having a diameter substantially equal to the largest diameter of the final core forming member.