Machines for boring holes

Claim 2

Apparatus as claimed in claim 1 wherein said clearing device comprises a tube having a helical screw conveyor on the outer surface thereof, the outer diameter of the helix being substantially the same diameter as the diameter of the cutting circle covered by the cutter during rotation.

Claim 3

Apparatus as claimed in claim 3 wherein the length of said screw conveyor can be increased by the addition of further lengths of helix mounted on tube, said tube carrying a bearing in which shaft extensions to drive said cutter are rotatably mounted connecting means being provided between adjacent tubes and shafts.

Claim 4

Apparatus as claimed in claim 1 wherein said cutter comprises a base rotatably carrying a plurality of frustra of cones, the larger edges of which form the cutting edges.

Claim 5

Apparatus as claimed in claim 1 wherein said cutter comprises a base carrying a series of teeth pointing forwardly in the direction of rotation and raked towards the face to be cut.

Claim 6

Apparatus as claimed in claim 1 wherein said cutter comprises a plurality of radius blades having curved cutting edges.

Claim 7

Apparatus as claimed in any claim 1 having a pilot auger selected from a gimlet auger and a helical auger.

Claim 8

Apparatus as claimed in claim 1 wherein said power transmission means includes epicyclic gear trains.

Claim 9

Apparatus as claimed in claim 9 wherein said epicyclic gear trains are provided with two sets of brake bands and operating gear, manual operation of one which controls driving of the cutter and manual operation of the other of which controls driving of said clearing device.

Claim 10

Apparatus as claimed in claim 1 wherein said interlinking means comprises a differential gear.

Claim 11

Apparatus as claimed in claim 11 wherein two sets of brake means and operating gear are provided, one on a part of said transmission means driving said cutter and one on a part of said transmission means driving said clearing device, manual operation of which causing stopping of one and speeding up of the other.

Claim 12

Apparatus as claimed in claim 11 wherein the differential gearing may be deprived at will of the operator of its freedom to differentiate.

Claim 13

Apparatus as claimed in claim 1 wherein said power transmission means include a clutch means operable to disconnect said cutter from said source of power and a further clutch means operable to disconnect said clearing device from said source of power.

Claim 14

Apparatus as claimed in claim 1 wherein said power source comprises a source of fluid pressure and said power transmission means a pair of separate fluid-powered motors, one to drive said cutter and one to drive said clearing device conduits connecting said source of fluid pressure to said fluid-powered motors in parallel and control means operable by an operator to control the rotation of said cutter and of said clearing device.

Claim 15

Boring apparatus comprising a frame, a rotatable cutter, a shaft mounting said cutter so as to be rotatable relative to said frame, a rotatable screw conveyor journaled on said shaft, a power source mounted on said frame, power transmission means mounted on said frame connecting said power source to said rotatable cutter and to said rotatable screw conveyor so that the torque of the one is balanced through said power transmission means against the torque of the other so that when both said cutter and said conveyor are rotated in opposite directions said frame is substantially free of torque, and manually operable control means connected to said power transmission means and operable by an operator selectively to control rotation of said cutter and said conveyor so that either or both may rotate according to the selection made by the operator.