AU463518B2 - Rotary cutter for excavation, especially for use with raise boring and tunnel boring machines - Google Patents

Description

41273 72 The present invention relates to rotary cutters, especially

raise boring and rotary cutters of the type employed in connection with

tunnel boring machines. is con- Cutters of the nature with which the present invention

structure, such as a cerned generally comprise a central supporting

a yoke-like arrangement shaft, which has its opposite ends supported in

member. The particular and on which shaft is mounted a rotary cutter

has a central annular cutter with which the present invention is concerned

a formation to be cut rib projecting therefrom which is pressed against

of the aforementioned while the cutter is moved substantially in the plane

central rib so as to remove material from the formation. on Cutters of the nature referred to are generally mounted

while simultaneously relatively large supports or heads which are rotated

in this manner dislodge being pressed toward the formation to be cut and

material from the formation. In the main, cutters of the nature referred

excavating operations to are used for cutting, or material removing or

for tunnels, or in in connection with rather large holes such as holes

connection with enlarging smaller holes, as is done in the.mining tech-

shaft at one nique referred to as "raise boring" wherein a horizontal

at another level. level might be connected with a horizontal shaft operations Cutters of the nature employed in the aforementioned

must be capable of are subject to considerable wear and loading and

overloads while reducing withstanding considerable shock and momentary

the formation engaged thereby.

the nature The present invention is concerned with a cutter of

for highly referred to so arranged and constructed as to provide

cutter. efficient reduction of a formation engaged by the

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41273/72 The present invention is also concerned with

a cutter of the nature referred to which will have

relatively long life while remaining in efficient

operating condition.

According to the present invention there is

provided a cutter, especially for use in hole forming

and enlarging during excavating procedures, and com-

prising; a support shaft, bearing means on said shaft,

end members fixed to said shaft and confining said

bearing means therebetween on said shaft, a rotary

cutting member surrounding said shaft between said end

members and supported on said bearing means, said rotary

cutting member having an outwardly projecting annular rib, and inserts of a hard wear resistant material embedded substantially radially in said rib and distri- buted circumferentially of said rib, said inserts com- prising a first arrangement of inserts comprising a row of inserts located in the central portion of said rib and a second arrangement of inserts located in the adjacent edge portions of said rib and spaced so as to protect the parent metal around the first inserts from wear.

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The nature of the present invention will become more clear

ly apparent upon reference to the following detailed specification

taken in connection with the accompanying drawing.

BRIEF SUMMARY OF THE INVENTION:

The cutter of one form of the present invention has a

central support shaft on which a pair of anti-friction bearings are confined in axial spaced relation between confining end members

fixed to the shaft. A steel cutter body is supported on the anti-

friction bearings and is rotatably confined between the end members and is sealed thereto to maintain lubricant in the space occupied

by the bearings while excluding foreign material therefrom. The rotatable cutter body is formed of steel and has a

radially outwardly projecting annular rib, preferably shaped

in cross section, and having inserted therein hardwear resistant

inserts which might, for example, be in the form of a cemented

metal carbide such as tungsten carbide.

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41273 i

The inserts may be arranged in the shaped rib of the

cutter body so that larger principal inserts are centrally located

in the rib and are distributed uniformly about the circumference of

the cutter body. Further, smaller inserts may be disposed in the lateral

sides of the rib and are disposed circumferentially intermediate the larger inserts and in this manner serve to maintain the gauge of the rib while at the same time protecting the cutter body from

being abraded away from the major inserts so that the major inserts

are at all times adequately supported.

DETAILED DESCRIPTION:

In the drawing, support shaft 10 carries spaced end mem-

bers 12 andAetween which are confined inner bearing races 14 of

antifriction bearings, and a spacer 15. The bearings include

rollers 16, cages 18 and outer races 20. The outer races support

a cylindrical rotary cutter element 22 having a single central ra-

dially outwardly projecting shaped rib 24 provided with dis-

tributed radial holes in which are mounted carbide inserts 26 and 28. Inserts 26 are mounted in the plane of the pick of the rib 24 and are cylindrical with the outer ends shaped to a formation

to conform to the shape of rib 24.

The carbide inserts 28 are also cylindrical, but have rounded outer ends, and are arranged in planes on opposite sides

of the central plane of the rib. The planes of the inner sides of

inserts 28 are in about the planes of the outer sides of inserts 26. Circumferentially, inserts 28 are disposed about midway bet-

ween adjacent ones of the larger inserts 26.

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Inserts 28 not only assist in breaking up the formation against

which the cutter is pressed, but, likewise, prevent the cutter body 22,

which is steel, from eroding away at the sides of inserts 26. By thus

preserving the support of inserts 26, the life of the illustrated cutter

is materially increased.

The space in which the bearings are located is sealed toward

the outside, as by sealing rings 30, to hold lubricant in the bearing

space and keep foreign material out of the bearing space.

A cutter constructed as disclosed and described has long life

and will withstand considerable abuse and remains in superior cutting

condition due to the protection afforded the major inserts 26 by the

smaller inserts 28 while the inserts 28 tend to maintain the gauge of the

groove cut by the rib of the cutter body thereby preventing excessive

wearing away of the steel of the cutter body along the sides of the ribs

and which would seriously reduce the strength of the support for the

main inserts 26.

In the drawing, the cutter is shown schematically mounted in

a shaped support bracket 32 and which support bracket would be,

in turn, secured to the rotary head of excavating equipment such as a

tunnel boring or raise boring machine. However, other supporting

arrangements are possible for connecting the cutter assembly to a

driving head.

Modifications may be made within the scope of the appended

claims.

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Claims (4)

41,273 72 The claims defining the invention are as follows

1. A cutter, especially for use in hole forming and enlarging during excavating procedures, and com-

prising; a support shaft, bearing means on said shaft,

end members fixed to said shaft and confining said

bearing means therebetween on said shaft, a rotary

cutting member surrounding said shaft between said end

members and supported on said bearing means, said

rotary cutting member having an outwardly projecting

annular rib, and inserts of a hard wear resistant

material embedded substantially radially in said rib and distributed circumferentially of said rib, said inserts comprising a first arrangement of inserts com- prising a row of inserts located in the central portion of said rib and a second arrangement of inserts located in the adjacent edge portions of said rib and spaced so as to protect the parent metal around the first inserts from wear.

2. A cutter according to Claim 1 in which all of said inserts are rod-like, said rib having substantially radial bores in which said inserts are mounted.

3. A cutter according to Claims 1 or 2 in which said.first inserts are larger in diameter than said second inserts.

4. A cutter according to any one of Claims 1 to 3 in which said rib is shaped and said first inserts are formed at the outer ends so as to conform to the shape of said rib. A cutter according to any one of Claims 1 to 4 in which said first inserts are spaced uniformly about the circumference of said rib and said second inserts are lisposed in axially extending radial planes located about

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41,273/72 midway between each pair of first inserts whereby each first insert is centrally located within a group of four

second inserts.

6. A cutter according to any one of Claims I to

in which said rib is shaped and said first inserts are

formed at the outer ends so as to conform to the shape of

said rib, said second inserts having rounded outer ends.

7. A cutter accordingto any one of Claims 1 to 6

in which said rib is shaped and said first inserts are

formed at the outer ends so as to conform to the shape of

said rib, said first inserts having the central axes thereof

in the central radial plane of said rib whereby the lateral

sides of said first inserts lie in a pair of further radial

planes on opposite sides of said central radial plane, said

second inserts having the axes thereof in common radial

planes and the axially inner sides thereof substantially in one of said further radial planes. 8. A cutter according to any one of Claims 1 to 7 in which said inserts comprise a cemented metal carbide. 9. A cutter according to any one of Claims 1 to 7 in which said inserts comprise cemented tungsten carbide. A cutter according to Claim 1 substantially as herein described with reference to the accompanying drawing.

DATED: 12th May, 1975 PHILLIPS ORMONDE AND FITZPATRICK Attorneys for KENNAIMETAL IFC.

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