Tool

Claim 2

A tool for scarifying a surface or removing ice therefrom, including: at least one pair of rotatably mounted opposing discs; each said disc including a central aperture by which the disc is mounted on an axle to rotate relative to the axle, a plurality of sharp teeth radiating conically outward from the rim of each said disc, said teeth being inclined out of a plane orthogonal to said axle, depth control means rotatable with each said disc on said disc axle, said depth control means being disposed transversely relative to said teeth and adjacent said teeth, said depth control means comprising a second plurality of teeth, radiating conically outward from the rim of each said disc, inclined out of said plane on the opposite side of said plane from the first said plurality of teeth so as to project transversely relative to the first said plurality of teeth; said first plurality of teeth alternating with said second plurality of teeth around the rim of said disc.

Claim 3

A tool as claimed in claim 1, wherein each said disc is comprised of two plates, each having a central aperture and each said plurality of teeth radiating conically outward from the rim of its associated said plate; said plates being abutted face to face with said teeth intermeshed and said apertures in alignment.

Claim 4

A tool as claimed in claim 1, wherein said discs of said at least one pair are spaced apart from each other at points of contact with said surface, and wherein said axles are non-parallel.

Claim 5

A tool as claimed in claim 3, further including a carriage element on which said at least one pair of discs is mounted, said carriage element being movable relative to a body of said tool, such that said disc axles can be moved to at least two different orientations relative to said body; wherein at each said orientation said discs are non-parallel with respect to each other, with respect to a direction of travel of the tool and with respect to a line orthogonal to said surface at a point of contact between said surface and said disc; whereby in use movement of the tool in a said direction of travel can cause said discs to roll and impose opposed sideways forces on said surface at spaced apart positions of contact with the surface.

Claim 6

A tool as claimed in claim 4, wherein said carriage element is movable about a carriage axis of rotation substantially orthogonal to a plane of symmetry between said non-parallel disc axles, such that said carriage element can be pitched at different angles within said plane of symmetry, different said angles providing different said orientations of the disc axles relative to the body.

Claim 7

A tool as claimed in claim 5, wherein said carriage element is rollably held on said body.

Claim 8

A tool as claimed in claim 5, wherein said carriage element is pivotally held on said body.

Claim 9

A tool as claimed in claim 5, wherein said carriage element is fastened to said body by a flexible stem.

Claim 10

A tool for scarifying a surface or removing ice therefrom, including: at least one pair of rotatably mounted opposing discs, each said disc including a central aperture by which the disc is mounted on an axle to rotate relative to the axle; said discs of a pair being spaced apart from each other at points of contact between said surface and said discs, and being oriented so as to rotate in non-parallel planes; each said disc including a plurality of sharp teeth radiating conically outward from the rim of the disc, inclined out of said plane of rotation of the disc, the direction of inclination of said teeth being opposed on the discs of said at least one pair; a carriage element on which said at least one pair of discs is mounted, said element being movable relative to a body of said tool about a carriage axis of rotation, such that said carriage element can be positioned at two different orientations relative to said body; wherein at each said orientation of the carriage element said discs are non-parallel with each other and with respect to a direction of travel of the tool; whereby movement of the tool in said direction of travel can cause said discs to roll and impart opposed sideways forces on said surface at spaced apart positions of contact with the surface; said sideways forces being in the direction of inclination of a plurality of said teeth; and movement of the tool in the opposite direction can cause said carriage element to move about said carriage axis of rotation to a different said orientation.

Claim 11

A tool for scarifying a surface or removing ice therefrom, including: at least one pair of rotatably mounted opposing discs, each said disc including a central aperture by which the disc is mounted on an axle to rotate relative to the axle; said discs of a pair being spaced apart from each other at points of contact between said surface and said discs, and being oriented so as to rotate in non-parallel planes; each said disc including a plurality of sharp teeth radiating conically outward from the rim of the disc, inclined out of said plane of rotation of the disc, the direction of inclination of said teeth being opposed on the discs of said at least one pair; a carriage element on which said at least one pair of discs is mounted, said element being movable relative to a body of said tool about a carriage axis of rotation, such that said carriage element can be positioned at two different orientations relative to said body; wherein at each said orientation of the carriage element said discs are non-parallel with each other and with respect to a direction of travel of the tool; whereby movement of the tool in said direction of travel can cause said discs to roll and impart opposed sideways forces on said surface at spaced apart positions of contact with the surface; said sideways forces being in the direction of inclination of a plurality of said teeth; and movement of the tool in the opposite direction can cause said carriage element to move about said carriage axis of rotation to a different said orientation.

Claim 12

A tool as claimed in claim 9, wherein each said disc includes a second plurality of teeth, radiating conically outward from the rim of said disc, inclined out of said plane on the opposite side of said plane from the first said plurality of teeth, and wherein at a first said orientation of the carriage element said opposed sideways forces are in the directions of inclination of a first plurality of teeth on each disc, and at a second said orientation of the carriage element said opposed sideways forces are in the directions of inclination of the second said plurality of teeth.

Claim 13

A tool as claimed in claim 10, wherein said second plurality of teeth project transversely across said first plurality of teeth, said first plurality of teeth alternating with said second plurality of teeth around the rim of said disc.

Claim 14

A tool as claimed in claim 11, wherein each said disc is comprised of two plates, each having a central aperture and each said plurality of teeth radiating conically outward from the rim of its associated said plate; said plates being abutted face to face with said teeth intermeshed and said apertures in alignment.

Claim 15

A tool as claimed in claim 11, wherein said discs of said at least one pair are spaced apart from each other at points of contact with said surface, and wherein said axles are non-parallel.

Claim 16

A tool as claimed in claim 9, wherein said carriage element is rollably held on said body.

Claim 17

A tool as claimed in claim 9, wherein said carriage element is pivotally held on said body.

Claim 18

A tool as claimed in claim 9, wherein said carriage element is fastened to said body by a flexible stem.