Disc cutter and method of replacing disc cutters

A rolling disc cutter for use in a mechanical excavation apparatus to exert pressure against substantially solid matter such as rock, compacted earth, or mixtures thereof by acting on a face thereof, said cutter of the type which upon rolling forms a kerf by penetration into said face so that, when two or more cutters are used, solid matter between a proximate pair of said kerfs is fractured to produce chips which separate from said face, wherein said disc cutter comprises:

• (a) a shaft, said shaft having a proximal end and a distal end;
• (b) a washer surface;
• (c) a cutter ring assembly, said cutter ring assembly further comprising
• (i) an annular cutter ring having an interior annulus defining portion and an outer ring portion, said outer ring portion including a cutting edge having diameter OD and radius R.sub.1
• (ii) a bearing assembly, said bearing assembly adapted
• (A) to substantially fit into said annulus of said cutter ring, and
• (B) in a close fitting relationship with said shaft, so that said cutter ring may rotate with respect to and be supported by said shaft,
• (iii) said bearing assembly comprising
• (A) a bearing, and
• (B) a seal, said seal adapted to fit sealingly between said washer surface and said cutter ring, so as to form a lubricant retaining seal for said interior annulus portion of said cutter ring;
• (d) a retainer assembly, said retainer assembly adapted to retain said cutter ring assembly onto said shaft;
• (e) a cap, said cap having an interior surface portion, said cap adapted to seal said interior annular portion of said cutter ring assembly, so that, in cooperation with said seal and said cutter ring, a lubricant retaining chamber is provided;
• (f) wherein said cutter ring further comprises:
• (i) a pair of laterally spaced apart support ridges, said ridges having therebetween a groove forming portion, said groove forming portion including
• (A) a pair of interior walls, and
• (B) an interior bottom surface interconnecting with said interior walls
• (ii) wherein said interior walls outwardly extend relative to said interior bottom surface to thereby define a peripheral groove around the outer edge of said outer cutter ring,
• (g) two or more hardened, wear-resistant inserts, said inserts substantially aligned within and located in a radially outward relationship from said groove, said inserts further comprising
• (i) a substantially continuous engaging contact portion of radius R.sub.1, said contact portion on the outer side of said inserts and adapted to act on said face, and
• (ii) a lower groove insert portion, said groove insert portion,
• (A) having a bottom surface shaped and sized in complementary matching relationship relative to said bottom surface of said groove, and
• (B) having first and second opposing exterior side surfaces, said first and second side surfaces being shaped and sized in a complementary matching relationship relative to said interior walls,
• (iii) a rotationwise front and rear portion,
• wherein said lower groove insert portion of said inserts fit within said groove in a close fitting relationship which defines a slight gap between said inserts and said interior walls, and
• (h) wherein a somewhat elastic preselected filler material is placed between and joins said inserts in a spaced apart relationship to said groove bottom and to said interior sidewalls, said preselected filler material having a modulus of elasticity so that said inserts can slightly move elastically relative to said cutter ring so as to tend to relieve stress and strain acting on said insert segments.

A rolling disc cutter for use in a mechanical excavation apparatus to exert pressure against substantially solid matter such as rock, compacted earth, or mixtures thereof by acting on a face thereof, said cutter of the type which upon rolling forms a kerf by penetration into said face so that, when two or more cutters are used, solid matter between a proximate pair of said kerfs is fractured to produce chips which separate from said face, wherein said disc cutter comprises:

• (a) an outer cutter ring, said cutter ring further comprising:
• (i) a pair of laterally spaced apart support ridges, said ridges having therebetween a groove forming portion, said groove forming portion including
• (A) a pair of interior walls, and
• (B) an interior bottom surface interconnecting with said interior walls
• (ii) wherein said interior walls outwardly extend relative to said interior bottom surface to thereby define a peripheral groove around the outer edge of said outer cutter ring,
• (b) two or more hardened, wear-resistant inserts, said inserts substantially aligned within and located in a radially outward relationship from said groove, said inserts further comprising
• (i) a substantially continuous engaging contact portion of radius R.sub.1, said contact portion on the outer side of said inserts and adapted to act on said face, and
• (ii) a lower groove insert portion, said groove insert portion,
• (A) having a bottom surface shaped and sized in complementary matching relationship relative to said bottom surface of said groove, and
• (B) having first and second opposing exterior side surfaces, said first and second side surfaces being shaped and sized in a complementary matching relationship relative to said interior walls,
• (iii) rotationwise, a rounded leading edge surface portion of reduced curvature relative to contact portion radius R.sub.1, and a rounded trailing edge surface portion of reduced curvature relative to contact portion radius R.sub.1,
• wherein said lower groove insert portion of said inserts fit within said groove in a close fitting relationship which defines a slight gap between said inserts and said interior walls, and
• (c) wherein a somewhat elastic preselected filler material is placed between and joins said inserts in a spaced apart relationship to said groove bottom and to said interior sidewalls, said preselected filler material having a modulus of elasticity so that said inserts can slightly move elastically relative to said cutter ring so as to tend to relieve stress and strain acting on said insert segments.

A kit for replacement of wear parts in a rolling cutter apparatus, said kit comprising:

• (a) a cutter ring assembly, said cutter ring assembly further comprising
• (i) an annular cutter ring having an interior annulus defining portion and an outer ring portion, said outer ring portion including a cutting edge having diameter OD and radius R.sub.1
• (ii) a bearing assembly, said bearing assembly adapted to substantially fit into said annulus of said cutter ring, and to be entirely laterally removable from a single side of said cutter ring, said bearing assembly comprising
• (A) a bearing, and
• (B) a seal.

A method for replacing wear parts in a rolling disc cutter of the type having a cantilever shaft mount, and wherein said cutter is of the type comprising

• (a) a relatively stiff shaft, said shaft having a proximal end and a distal end, and an axis for rotation thereabout;
• (b) a washer surface;
• (c) a cutter ring assembly, said cutter ring assembly further comprising
• (i) an annular cutter ring having an interior annulus defining portion and an outer ring portion, said outer ring portion including a cutting edge having diameter OD and radius R.sub.1
• (ii) a bearing assembly, said bearing assembly adapted
• (A) to substantially fit into said annulus of said cutter ring, and
• (B) in a close fitting relationship with said shaft, so that said cutter ring may rotate with respect to and be supported by said shaft,
• (iii) said bearing assembly comprising
• (A) a bearing, and
• (B) a seal, said seal adapted to fit sealingly between said washer surface and said cutter ring, so as to form a lubricant retaining seal for said interior annulus portion of said cutter ring;
• (d) a retainer assembly, said retainer assembly adapted to retain said cutter ring assembly onto said shaft, and wherein said retainer assembly further comprises
• (i) a retainer having
• (A) an outer surface, and
• (B) one or more retainer aperture(s) therethrough, and
• (ii) one or more fastener(s)
• (iii) wherein said fastener(s) pass through fastener aperture(s) extending through said retainer, and are received by threaded receptacle(s) at said distal end of said shaft;
• (e) a cap, said cap adapted to seal said interior annular portion of said cutter ring assembly, so that, in cooperation with said seal and said cutter ring, a lubricant retaining chamber is provided;
• said replacement method comprising:
• (a) removing said cap from said cutter ring;
• (b) removing fasteners from said retaining assembly;
• (c) removing said retainer;
• (d) removing said cutter ring assembly from said shaft;
• (e) replacing said removed cutter ring assembly with a new or reconditioned cutter ring assembly;
• (f) replacing said retainer and said fasteners
• (g) replacing said cap.

A cutterhead apparatus for use in mechanical excavation, comprising:

• a cutterhead body,
• a plurality of rolling type cutters rotatably mounted on said cutterhead body,
• wherein at least one of said cutters comprises a cutter ring, and
• wherein said cutter ring further comprises at least one circumferential groove, said groove further comprising a bottom portion and opposite sidewall portions, and
• two or more hard metal inserts, said inserts having an upper wear portion and a lower support portion, said lower support portion including a bottom, a first sidewall, a second sidewall, a front portion, and a rear portion,
• wherein said bottom of said lower support portion is sustantially shaped and sized complementary to said groove
• and wherein a preselected elastic braze filler alloy material is placed in a gap between, below, and beside said inserts, to affix said inserts in a spaced apart relationship near (i) to each other, (i) to said groove bottom portion, and (iii) to said opposite sidewall portions, and which avoids impingement of said inserts against said cutter ring, and wherein said elastic braze filler alloy material allows said inserts to move elastically relative to said cutter ring so as to relieve a portion of stress and strain acting on said inserts.

A cutterhead apparatus for a repetitive motion mechanical excavation apparatus, said apparatus adapted to form a bore through substantially solid matter such as rock, compacted earth, or mixtures thereof by acting on a face thereof, said apparatus of the type which forms adjacent kerfs in said face so as to fracture said solid matter between a proximate pair of said kerfs to produce chips which separate from the face being bored, said apparatus comprising:

• a rotatable cutterhead body, said cutterhead body comprising a forward side directed toward said face and a rearward side directed toward said bore,
• two or more disc cutters rotatably mounted on said cutterhead body in a manner such that a cutting edge of said cutters is positioned forwardly toward said face,
• wherein each disc cutter comprises
• (a) a large diameter shaft, said shaft having an inside end and an outside end,
• (b) a washer surface,
• (c) a cutter ring assembly, said cutter ring assembly further comprising
• (i) an annular cutter ring having an interior annulus portion and an outer ring portion,
• (ii) a bearing assembly, said bearing assembly adapted to fit into said annulus of said cutter ring, said bearing assembly comprising
• (A) a bearing, and
• (B) a seal, said seal adapted to fit against said washer surface, so as to form a lubricant retaining seal for said interior annulus portion of said cutter ring,
• (C) a retainer assembly, said retainer assembly adapted to retain said cutter ring assembly onto said shaft,
• (D) a cap, said cap having an interior portion adapted to seal said interior annular portion of said cutter ring assembly to form a lubricant retaining chamber.