U.S. patent number RE31,511 [Application Number 06/318,618] was granted by the patent office on 1984-01-31 for rotary cutterhead for an earth boring machine.
This patent grant is currently assigned to The Robbins Company. Invention is credited to Barry A. Spencer.
United States Patent |
RE31,511 |
Spencer |
January 31, 1984 |
Rotary cutterhead for an earth boring machine
Abstract
The main frame of the cutterhead comprises a plurality of radial
spoke beams which are interconnected between a box-like hub
structure and an annular box beam by which the cutterhead is
mounted for rotation. Cutter mounting wells are defined by and
between side wall portions of the radial spoke beams. The mined
material passes rearwardly through the cutterhead via openings
between adjacent radial spoke beams and open spaces in the cutter
mounting wells. Cutter mounts span laterally between the side plate
members and laterally brace the radial spoke beams in addition to
mounting the cutters. The radial spoke beams curve rearwardly at
their outer ends and connect to the annular box beam at a location
spaced enough rearwardly from the front portions of the spoke beams
that a room is defined within the cutterhead. Roller type cutters
are installed onto and removed from the cutterhead frame from the
rear side of the cutterhead.
Inventors: |
Spencer; Barry A. (Redmond,
WA) |
Assignee: |
The Robbins Company (Kent,
WA)
|
Family
ID: |
26981581 |
Appl.
No.: |
06/318,618 |
Filed: |
November 5, 1981 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
931384 |
Aug 7, 1978 |
04193637 |
Mar 18, 1980 |
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Current U.S.
Class: |
299/56; 299/106;
299/58 |
Current CPC
Class: |
E21B
10/12 (20130101); E21D 9/0879 (20160101); E21D
9/12 (20130101); E21D 9/112 (20130101) |
Current International
Class: |
E21D
9/10 (20060101); E21D 9/11 (20060101); E21D
9/12 (20060101); E21D 9/08 (20060101); E21B
10/12 (20060101); E21B 10/08 (20060101); E21C
025/16 () |
Field of
Search: |
;291/31,55,56,58,86,90
;175/53,95,96 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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13907 of |
|
1897 |
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GB |
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762416 |
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Nov 1956 |
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GB |
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284008 |
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Dec 1970 |
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SU |
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Other References
Robbins Drawings D10665, 12-30-75. .
Robbins Drawings D8453, 9-20-74, D10679, 2-9-76. .
Chapter 21 of 1976 Rapid Excavation and Tunneling Conference
Proceedings pp. 355-376, Jun. 14, 1976. .
Photo of Robbins Models 144-151, 165-162, 352-128..
|
Primary Examiner: Pate, III; William F.
Attorney, Agent or Firm: Graybeal & Cullom
Claims
What is claimed is:
1. A main frame for a rotary cutterhead of an earth boring machine,
said main frame comprising:
an annular box beam by which the cutterhead is mounted onto an
earth boring machine, for rotation about an axis of rotation;
a box-like hub structure comprising peripheral wall means defining
a center space;
a plurality of radial spoke beams having inner ends which are
integrally connected to the peripheral wall means of the hub
structure and outer ends which are integrally connected to the
annular box beam, each said radial spoke beam comprising a pair of
spaced apart side plate members;
roller cutter mounts within said radial spoke beams comprising wall
members which extend transversely of the radial spoke means and are
integrally connected at their ends to the spaced apart side plate
members, to also function as structural brace members for the
radial spoke beams;
wherein the cutter mounts are adapted for installation and removal
of roller cutters from the rear side of the cutterhead, and
wherein said main frame is configured to provide an interior space
for a workman which is large enough to provide room for
installation and removal of roller cutters from behind the
cutterhead.
2. A main frame according to claim 1, wherein each radial spoke
beam extends rearwardly as it extends radially outwardly from the
hub structure to the annular box beam.
3. A main frame according to claim 1, wherein the peripheral wall
means of the hub structure comprises six walls interconnected to
give the hub structure a generally hexahedral form, and wherein the
main frame comprises six radial spoke beams, with the inner ends of
the radial spoke beams being connected to the hub structure
generally at the corner regions where the walls of the hub
structure meet each other.
4. A rotary cutterhead for an earth boring machine, comprising:
a main frame comprising:
an annular hollow box beam by which the cutterhead is mounted onto
an earth boring machine, for rotation about an axis of
rotation;
a box-like hub structure comprising peripheral wall means defining
a center space; and
a plurality of radial spoke beams having inner ends which are
integrally connected to the peripheral wall means of the hub
structure and outer ends which are integrally connected to the
annular box beam, each said radial spoke beam comprising a pair of
spaced apart side plate members defining spaces between them;
a center cutter assembly comprising a plurality of roller cutters
and means mounting said roller cutters within the center space of
the hub structure, with peripheral portions thereof projecting
forwardly from the cutterhead main frame;
a plurality of roller cutters radially outwardly of said center
cutter assembly and means for mounting them within the spaces
between the side plate members, with peripheral portions thereof
projecting forwardly from the cutterhead main frame;
wherein the means for mounting the roller cutters between the side
plate members comprises wall members which extend transversely of
the radial spoke means and are integrally connected at their ends
to the spaced apart side plate members, to also function as
structural brace members for the radial spoke beams;
wherein the means for mounting the roller cutters between the side
plate members provide for installation and removal of the roller
cutters from the rear side of the cutterhead; and
wherein said main frame is configured to provide an interior space
for a workman which is large enough to provide room for
installation and removal of the roller cutters from behind the
cutterhead.
5. A rotary cutterhead according to claim 4, comprising roller
gauge cutters generally at the periphery of the cutterhead, and
wherein in the regions of the gauge cutters the side plate members
of the radial spoke beams curve rearwardly generally over the
interior space, and wherein such regions the means mounting the
gauge cutters between the side plate members defines installation
and removal paths which extend generally vertically in regions
forwardly of the annular box beam.
6. A rotary cutterhead according to claim 4, wherein spaces exist
between the radial spoke beams through which mined material may
pass axially through the cutterhead.
7. A rotary cutterhead according to claim 4, wherein each radial
spoke beam extends rearwardly as it extends radially outwardly from
the hub structure to the annular box beam.
8. A rotary cutterhead according to claim 4, wherein the peripheral
wall means of the hub structure comprises six walls interconnected
to give the hub structure a generally hexahedral form, and wherein
the main frame comprises six radial spoke beams, with the inner
ends of the radial spoke beams being connected to the hub structure
generally at the corner regions where the walls of the hub
structure meet each other.
9. A rotary cutterhead for an earth boring machine, comprising:
a main frame comprising:
an annular beam by which the cutterhead is mounted onto an earth
boring machine, for rotation about an axis of rotation; and
a plurality of radial spoke beams, each comprising a pair of spaced
apart side plate members defining spaces between them, said side
plate members extending generally vertically at the front of the
cutterhead and at their radially outer ends curving rearwardly;
a plurality of roller cutters and cutter mount means for mounting
them within the spaces between the side plate members, with
peripheral portions thereof projecting forwardly of the main frame,
said roller cutters including a gauge cutter mounted between the
generally rearwardly extending radially outer end portions of the
side plate members of at least some of said radial spoke beams,
said cutter mount means providing for installation and removal of
the roller cutters from the rear side of the cutterhead, and
wherein said main frame is configured to provide an interior space
in the cutterhead that is large enough to provide room for
installation and removal of said roller cutters from behind the
cutterhead; and
wherein the cutter mount means for the gauge cutters define
installation and removal paths which extend generally vertically in
a region of such interior space that is located forwardly of the
annular beam.
10. A rotary cutterhead according to claim 9, wherein said cutter
mounts also function as transverse structural braces for the radial
spoke beams.
11. A main frame for a rotary cutterhead of an earth boring
machine, said main frame comprising:
an annular box beam by which the cutterhead is mounted onto an
earth boring machine, for rotation about an axis of rotation;
a box-like hub structure comprising peripheral wall means defining
a center space;
a plurality of radial spoke beams having inner ends which are
integrally connected to the peripheral wall means of the hub
structure and outer ends which are integrally connected to the
annular box beam, each said radial spoke beam comprising a pair of
spaced apart side plate members; and
wherein each radial spoke beam extends rearwardly of the hub
structure as it extends radially outwardly from the hub structure
to the annular box beam.
12. An earth boring machine, comprising:
a cutterhead support including a relatively large central
passageway;
bearing means on said cutterhead support surrounding said
passageway;
a rotary cutterhead comprising:
an annular box beam by which the cutterhead is mounted onto said
bearing, for rotation about an axis of rotation;
a box-like hub structure comprising peripheral wall means defining
a center space; and
a plurality of radial spoke beams having inner ends which are
integrally connected to the peripheral wall means of the hub
structure and outer ends which are integrally connected to the
annular box beam, each said radial spoke beam comprising a pair of
spaced apart side plate members defining spaces between them;
a center cutter assembly comprising a plurality of roller cutters
and center cutter mount means for detachably mounting said roller
cutters within the center space of the hub structure, with
peripheral portions thereof projecting forwardly from the
cutterhead main frame, and providing for installation and removal
of the roller cutters from behind the cutterhead; and
wherein spaces exist between the spoke beams through which mined
material may pass axially through the cutterhead;
a plurality of roller cutters spaced radially outwardly of said
center cutter assembly and cutter mount means for detachably
mounting them within the spaces between the side plate members,
with peripheral portions thereof projecting forwardly from the
cutterhead main frame, and providing for installation and removal
of the roller cutters from behind the cutterhead; and
mined material receiving collector means supported within said
passageway, for movement between a forward position in which it is
located partially within the inner space of the cutterhead, in a
position to receive the mined material, and a retracted rearward
position in which it is spaced far enough rearwardly from the
center cutter assembly to provide sufficient room for installation
and removal of the center cutter assembly into and out from the
center space of the box-like hub structure.
13. A rotary cutterhead according to claim 12, comprising roller
gauge cutters generally at the periphery of the cutterhead, and
wherein in the regions of the gauge cutters the side plate members
of the radial spoke beams curve rearwardly generally over the
interior space, and wherein such regions the means mounting the
gauge cutters between the side plate members defines installation
and removal paths which extend generally vertically in regions
forwardly of the annular box beam. .Iadd. 14. A main frame for a
rotary cutterhead of an earth boring machine, said main frame
comprising:
an annular beam having mounting means by which the cutterhead is
mounted onto the earth boring machine for rotation about an axis of
rotation;
a central hub structure disposed forwardly of the annular beam;
and
a plurality of radial spoke beams having inner ends integrally
connected to the hub structure, intermediate portions extending
rearwardly and radially outwardly from the hub structure to the
annular beam and outer ends which are integrally connected to the
annular beam thereby to form the main frame in a generally dome
shape to define an open interior space within the main frame, each
of the radial spoke beams having side portions defining an elongate
opening extending substantially along the entire length of the beam
and rearwardly entirely through the beam in the direction along the
rotational axis of the cutterhead. .Iaddend..Iadd. 15. The main
frame according to claim 14, wherein the annual beam is constructed
in the form of a hollow box beam. .Iaddend..Iadd. 16. The main
frame according to claim 14 or 15, wherein the hub structure is
formed in a box-like shape having peripheral wall portions defining
a central opening. .Iaddend..Iadd. 17. The main frame according to
claim 14 or 15, wherein the side portions of each of the radial
spoke beams includes a pair of spaced apart side plate members.
.Iaddend. .Iadd. 18. A main frame for a rotary cutterhead of an
earth boring machine, said main frame comprising:
an annular beam by which the cutterhead is mounted onto the earth
boring machine for rotation about an axis of rotation;
a central hub structure disposed forwardly of the annular beam;
a plurality of radial spoke beams having inner ends integrally
connected to the hub structure, intermediate portions extending
rearwardly and radially outwardly from the hub structure to the
annular beam and outer ends which are integrally connected to the
annular beam thereby to form the main frame in a generally dome
shape, each of the radial spoke beams having side portions defining
an elongate opening extending through and substantially along the
entire length of the beam; and
roller cutter mounts having members which extend transversely
across the spoke beam elongate openings to intersect transverse
portions of the beams to brace the beams. .Iaddend..Iadd. 19. A
rotary cutterhead for an earth boring machine, comprising:
a main frame having
an annular beam by which the cutterhead is mounted on an earth
boring machine for rotation about an axis of rotation;
a central hub structure disposed forwardly of the annular beam and
including a central opening; and
a plurality of radial spoke beams having inner ends which are
integrally connected to the hub structure and outer ends which are
integrally connected to the annular beam, each of the radial spoke
beams including side portions defining an elongate opening
extending through and along substantially the entire length of the
radial spoke beam;
roller cutter mounts within the radial spoke beams, the cutter
mounts having members which extend transversely of the radial spoke
beams to span across the radial spoke beam openings to form cutter
compartments and to reinforce the radial spoke beams;
wherein the cutter mounts are adapted for installation and removal
of roller cutters from the rear side of the cutterhead; and
wherein the main frame is configured to provide an interior space
for a workman which is large enough to provide room for
installation and removal of the roller cutters from behind the
cutterhead. .Iaddend..Iadd. 20. The rotary cutterhead according to
claim 19, wherein the annular beam is formed generally in the shape
of a hollow torus. .Iaddend..Iadd. 21. The rotary cutterhead
according to claim 19, wherein the side portions of each of the
radial spoke beams includes a pair of spaced apart side plate
members, the side plate members curving rearwardly as they extend
radially outwardly from the hub structure to the annular beam.
.Iaddend. .Iadd. 22. A rotary cutterhead according to claim 19,
wherein
the roller cutter mounts mount roller gauge cutters at the
periphery of the cutterhead;
the radial spoke beams in the regions of the gauge cutters curve
rearwardly generally over the interior space of the main frame as
they extend radially outwardly from the hub structure to the
annular beam to form the cutterhead in a generally dome shape;
and
the roller cutter mounts which mount the gauge cutters define
generally vertical installation and removal paths at locations
forwardly of the annular beam. .Iaddend..Iadd. 23. The rotary
cutterhead according to claim 19, further comprising a center
cutter assembly having a plurality of roller cutters, and means for
mounting the roller cutters within the center opening of the hub
structure, with peripheral portions of the roller cutters
projecting forwardly of the cutterhead main frame. .Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to rock boring machines, and in
particular to a new cutterhead construction for such a machine.
2. Description of the Prior Art
U.S. Pat. No. 3,756,332, granted Sept. 4, 1973, to Clayton H.
Crane, and assigned to the The Robbins Company, discloses a popular
open face cutterhead and a typical cutter arrangement on a
cutterhead. The cutterhead includes a plurality of disc cutter
assemblies positioned for cutting concentric kerfs in the rock. The
disc cutters include sloping breaker surfaces flanking
circumferential cutting edges. These breaker surfaces serve to
fracture and dislodge the rock material between kerfs which are cut
by the cutting edges.
The cutter assemblies are mounted onto the front side of the
cutterhead. Most of them are mounted on the front walls of radial
spoke beams, while others are mounted on the front side of
auxiliary frame structure that is angularly offset from the radial
spoke beams. A disadvantage of this type of arrangement is that
whenever it is necessary to replace the cutters, which is a
frequent occurrence, it is necessary to back the cutterhead up from
the tunnel face and then send a workman into the quite dangerous
region forwardly of the cutterhead.
It is known to mount the cutters onto the rear side of the
cutterhead so that cutter replacement can be made in relative
safety behind the cutterhead. However, such rear mounting is most
normally associated with closed face cutterheads and has not been
used with open face cutterheads. The term "open face tunneling
machine" is used herein to mean a cutterhead comprising a plurality
of radial spoke beams on which most of the cutters are mounted,
with spaces being provided between adjacent beams through which the
mined material passes. In a closed face cutterhead the mined
material is picked up only at the periphery of the cutterhead,
except for pieces which are small enough to pass through the small
spaces which exist about each roller cutter element.
Examples of rear mounting of roller cutters onto solid face
cutterheads, existing in the patent literature, are disclosed by
U.S. Pat. No. 3,358,782, granted Dec. 19, 1967 to Karl G. Bechem,
and by U.S. Pat No. 3,444,939, granted May 20, 1969 also to Karl G.
Bechem.
For some types of tunnel boring jobs the open face or spoke style
of cutterhead possesses advantages over the closed face style of
cutterhead in that the cut material can pass through the cutterhead
at almost any level of the tunnel face and need not fall down to be
picked up by peripheral buckets. A primary object of the present
invention is to provide an improved open face type cutterhead on
which all of the roller cutters, including a center cutter assembly
and gauge cutters, are removable from the back side of the
cutterhead.
SUMMARY OF THE INVENTION
According to an aspect of the present invention, the cutterhead
main frame comprises a box-like hub structure having peripheral
wall means defining a center space. A plurality of radial spokes
are integrally connected to the peripheral wall means of the hub
structure and extend radially outwardly therefrom to at their outer
ends be integrally connected to an annular box beam which mounts
the cutterhead for rotation about an axis of rotation. Each radial
spoke beam comprises a pair of spaced apart side plate members.
According to an aspect of the invention, roller type cutters are
mounted between the side plate members by cutter mounts which
extend transversely of the radial spoke beams and are integrally
connected at their ends to the spaced apart side plate members, to
also function as structural brace members for the radial spoke
beam.
According to an aspect of the invention, the cutter mounts are
adapted for installation and removal of the roller cutters from the
rear side of the cutterhead. The main frame is configured to
provide a room or space inside the cutterhead large enough to
provide room for installation and removal of the roller cutters
from behind the cutterhead.
According to an aspect of the invention, the side plate members
extend generally vertically at the front of the cutterhead and at
their outer ends curve rearwardly before connecting to the annular
box beam. The gauge cutters are mounted between the rearwardly
extending outer end portions of the side plate members of at least
some of the radial spoke beams. Installation and removal paths for
the gauge cutters extend generally vertically in a region of the
interior space that is located forwardly of the annular beam and
rearwardly of the front portions of the radial spoke beams.
According to an aspect of the invention, the center cutter assembly
is mounted within the interior of the hub structure. The conveyor
for removing mined material rearwardly from the region of the
cutterhead and its collector structure may be mounted for movement
between a forward position in which the collector structure is in a
collecting position adjacent the rear side of the cutterhead and a
retracted position in which enough clearance is provided forwardly
of it to allow installation and removal of the center cutter
assembly.
The main frame of the cutterhead is relatively simple and the side
plate members which define the radial spoke beams, and the cutter
mount structure therein, perform the second function of mounting
the roller cutters for easy removal from the rear side of the
cutterhead. The rearwardly curved nature of the outer end portions
of the side plate members provides the necessary room within the
cutterhead to permit installation and removal of the gauge cutters
from behind the cutterhead and also strengthens the peripheral
region of the cutterhead. The edgewise orientation of the side
plate members relative to the thrust forces imposed on the radial
spoke beams contributes to the beams being relatively strong while
relatively simple in construction. The annular box beam to which
the radial spoke beam side plate members are connected provides a
quite strong and rigid collector for the forces which are imposed
on the radial spoke beams and evenly distribute such forces to the
combination thrust and radial bearing which serves to mount the
cutterhead for rotation.
Other features, characteristics and advantages of the present
invention are discussed in, or will be apparent from, the following
description of a typical and therefore non-limitative example of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawing, like element designations refer to like parts
throughout, and:
FIG. 1 is a fragmentary side elevational view, with some parts in
axial section, of a tunnel boring machine which includes a
cutterhead exemplifying the present invention, with the portion of
the machine which is disposed rearwardly of the mid-portion of the
gripper assembly being omitted;
FIG. 2 is a front elevational view of the cutterhead;
FIG. 3 is a sectional view taken through the boring machine
substantially along line 3--3 of FIG. 1, showing the rear side of
the cutterhead support in elevation;
FIG. 4 is a cross-sectional view taken substantially along line
4--4 of FIG. 1, showing the gripper assembly in elevation, with
some parts broken away for clarity of illustration of other
parts;
FIG. 5 is an isometric view taken from the front and looking down
towards an upper portion and a side portion of the basic cutterhead
frame, with a foreground portion of such frame being cut away;
FIG. 6 is a view similar to FIG. 5, but looking towards the rear
side of the basic cutterhead frame, with an upper foreground
portion of such frame being cut away for clarity of illustration of
certain parts;
FIG. 7 is a fragmentary isometric view of the hub region of the
cutterhead frame, taken from the rear of the cutterhead;
FIG. 8 is a fragmentary elevational view of the center region of
the cutterhead, with some parts in section;
FIG. 9 is a sectional view taken substantially along line 9--9 of
FIG. 8;
FIG. 10 is a fragmentary isometric view of the center region of the
cutterhead, taken from behind the cutterhead, with the center
cutter exploded out from its mounted position;
FIG. 11 is a fragmentary view, partially in section and partially
in elevation, of an intermediate cutter, showing a way of mounting
the cutter;
FIG. 12 is a split sectional view, the upper portion being taken
along line 12a--12a and the lower portion along line 12b--12b, of
FIG. 11;
FIG. 13 is an exploded isometric view of an intermediate cutter and
its mounting structure;
FIG. 14 is a fragmentary view of that portion of FIG. 1 in the
vicinity of the forward end of the conveyor, with the conveyor
being shown in a retracted position back from the inner side of the
cutterhead, and including a broken line showing of the forward or
in use position of the conveyor; and
FIG. 15 is a sectional view taken substantially along line 15--15
of FIG. 14, showing the mechanism which mounts the front end of the
conveyor.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The illustrated embodiment is the best mode of the invention
presently known to applicant.
Referring to FIG. 1, the tunneling machine itself is of the rotary
cutterhead hard material disintegrating type. The advance direction
is coincident to the rotary axis of the cutterhead and the
tunneling machine follows the cutterhead into the opening formed
thereby.
The basic parts of the tunneling machine are a main frame which
includes a cutterhead support 10 attached to a tubular shield 12
and a rearwardly projecting beam 14. A gripper assembly 16 is
supported for relative sliding movement along a straight portion of
the beam 14. Thrust rams 18, located on both sides of the machine,
are interconnected between the cutterhead support 10 and the
gripper assembly 16, generally in the manner disclosed by U.S. Pat.
No. 3,203,737, granted August 31, 1965 to Richard J. Robbins,
Douglas F. Winberg and John Galgoczy, and by U.S. Pat. No.
3,861,748, granted Jan. 21, 1975, to David T. Cass.
As is well known in the tunneling machine art, the gripper assembly
16 is positioned forwardly on the beam 14. Its gripper shoes 17 are
hydraulically moved outwardly into gripping contact with the side
walls of the tunnel. Then, the thrust rams 18 are extended while
the rotary cutterhead is being rotated by means of a plurality of
drive motors 22. Motors 22 drive circular gears (not shown) which
mesh with a large diameter gear 24 that is an integral part of the
rotating cutterhead 20. When the cylinders 18 reach the forward
limits of travel the gripper pads 17 are retracted and the
cylinders 18 are retracted for the purpose of drawing the gripper
assembly forward into a new position. Then, the gripper pads 17 are
again moved outwardly into contact with the tunnel wall and the
boring procedure is repeated.
The tunneling machine of this invention is adapted to cut a
moderately crowned tunnel face, an idea which is itself old, as
shown by U.S. Pat. No. 3,232,670, granted Feb. 1, 1966, to Richard
J. Robbins and Douglas F. Winberg.
Roller cutters 26, 28, 30 (FIG. 2) are used and the arrangement or
pattern of these cutters may be basically like what is shown by
U.S. Pat. No. 3,756,332, granted Sept. 4, 1973, to Clayton H.
Crane. The disc cutters are arranged to cut concentric kerfs (e.g.
spaced 23/4"-4" apart) and to fracture the rock between kerfs. The
frame construction of the cutterhead shown by U.S. Pat. No.
3,756,332 is not detailed in such patent, but is to a great extent
disclosed by U.S. Pat. No. 3,861,748. Such frame comprises a
plurality of radial spoke members or beams which are connected
together at the center region of the cutterhead and which are
connected at their outer ends to an annular mounting plate. The
radial beams are tapering box beams having forward walls onto which
most of the roller cutter assemblies are mounted. Open spaces are
provided between such beams through which mined material moves
axially rearwardly to a conveyor which removes such material
rearwardly through the tunnel. Scoop means are .[.mounting.].
.Iadd.mounted .Iaddend.along the trailing edges of such openings
for scooping up such material and directing it through the
cutterhead.
The cutterhead 20 of the present invention has some similarity to
the open faced cutterhead disclosed by the aforementioned U.S. Pat.
Nos. 3,756,332 and 3,861,748. However, the frame construction is
completely different and the roller cutters are mounted in a
different manner. The roller cutters 26, 28, 30 are all installed
onto and removed from the cutterhead 20 from the rear side of the
cutterhead 20. This makes it unnecessary for the tunneling machine
to be backed up and for a workman to go down into the very
hazardous region between the front of the cutterhead and the tunnel
face for the purpose of changing cutters.
As discussed above, the general idea of mounting cutters onto a
cutterhead from the rear is not new, but the disclosed construction
of the cutterhead to facilitate such assembly and removal is new.
Also, such construction allows rear installation and removal of the
gauge cutters as well as the face cutters and theis capability is
new.
According to the present invention, the frame of the cutterhead
comprises a box-like hub structure 32 which may be a one-piece
casting. Hub structure 32 preferably is of a generally hexahedral
form and comprises six peripheral walls 34, 36, 38, 40, 42, 44 and
a front wall 46 (FIGS. 2 and 5). In larger cutterheads the number
of radial spokes may be increased to eight. In smaller cutterheads
the number may be reduced to four, for example. A window 47 is
provided in the front wall 46 and the rear side of hub structure 32
is open. A plurality of radial spoke beams 48 are integrally
connected (e.g. welded) to the hub structure 32 generally at the
corner regions where the walls 34, 36, 38, 40, 42, 44 meet each
other. As shown best by FIG. 7, radial stub walls may be provided
at the corners. Each radial spoke beam 48 comprises a pair of
spaced apart steel plate side walls 50, 52. The inner ends of side
walls 50, 52 abut against end or side portions of the stub walls
and are welded thereto. Each side wall 50, 52 occupies a plane
which is substantially parallel to the tunnel axis. Thus, it can be
said that in the fore and aft direction the side walls 50, 52 are
parallel to each other and to the tunnel axis. For the most part
the beams 48 are open both front and rear so that a front to rear
open space exists between their side walls 50, 52. Spaces also
exist between adjacent beams 48.
The front edges 54, 56 of the side plate members 50, 52 closely
follow the desired contour of the tunnel face. As best shown by
FIG. 1, this shape is preferably a relatively flat crown shape with
a generally circular curvature existing at the outer regions.
As shown by FIGS. 1, 5 and 6, the side plate members 50, 52, extend
generally radially outwardly from the center hub structure 32 and
in their outer regions curve rearwardly about ninety degrees. The
upper rear ends of the side plate members 50, 52 are integrally
attached to a frusto-conical shape forward wall 58 of an annular
box beam 60. Box beam 60 also includes a frusto-conical peripheral
wall 62, a frusto-conical upper rear wall 64, a relatively husky
mounting ring 66, which is also a lower rear wall, and a
cylindrical inner wall 68. Of course, in other installations this
construction of the annular box beam could be different.
The illustrated configuration of the side walls 50, 52 results in
radial beams 48 which are quite strong in the direction of the
thrust loads applied to them, since the side walls extend edgewise
to the direction of thrust loading. Also, the configuration of side
walls 50, 52 and thier location of connection with the annular box
beam 60 results in a space existing between each pair of side walls
50, 52, throughout the full extent of beams 48, i.e. from where
they are connected to the center hub member 32 out to where they
are connected to the annular box beam 60, in which the roller
cutters are mounted. Such configuration of side walls and the
location of attachment of the members 50, 52 to the beam 50, also
provides a sufficient amount of interior apace IS (FIG. 1) within
the cutterhead 20 to allow installation and removal of all of the
cutters from behind the cutterhead. Installation and removal paths
for the gauge cutters 30 are defined in a generally vertical
direction, forwardly of the box beam forward wall 58.
The cutterhead support includes a central axial passageway 70 which
houses the front portion 72 of a conveyor assembly and a hopper or
collector 74 associated therewith. The cutterhead support also
supports a large diameter bearing 76 of a type which is commonly
used in tunneling machines having open centered cutterheads. The
box beam 60 is secured to a second smaller diameter box beam 78
which is directly supported for rotation by the bearing 76. The
mounting ring 66 is secured to a front radial wall 80 of box beam
78.
The usual dirt seals 82, 84 are provided between the rotating and
nonrotating parts at each end of the bearing 76.
As best shown by FIGS. 1 and 7-10 the center cutter assembly 28 is
mounted inside of the center hub structure 32. By way of typical
and therefore non-limitative example, the center cutter assembly
itself may be constructed very much like the center cutter assembly
disclosed by the aforementioned U.S. Pat. No. 3,756,332, with the
number of disc cutters being a variable. However, the manner of
mounting is different.
In the illustrated embodiment the center cutter assembly 28
comprises four disc cutters 86. Mounting frames are used which
permit mounting of the center cutter assembly 28 from the rear side
of the cutterhead. Center cutter assembly 28 may include two parts,
each including a pair of disc cutters 86 mounted on a single shaft
87. When the center cutter assembly 28 is inserted into the open
center of hub structure 32, support portions 88 enter spaces
between retainer portions 90 of the hub structure 32. These
retainer portions 90 border the sides of the window 47. The center
cutter mounting frames also includes mounting flanges 92, formed to
include openings 94 (FIG. 9) for receiving bolts 96 which thread
into threaded openings 98 which are formed in retainer portions
90.
Referring now to FIGS. 11-13, the single disc cutter units 26 which
are mounted within the radial beams 48 are mounted by a cutter
mount structure which also functions as a lateral reinforcement for
the beams 48. This structure may comprise a box 99 which includes a
pair of radially spaced apart end walls 100, 102. The end walls
100, 102 are welded into place between the beam side walls 50, 52
to form cutter compartments or wells. The inner face of each end
member 100, 102 is constructed to include an avenue 108, 110 sized
to receive an end portion 104, 106 of the stator part of the cutter
assembly 26, and also load transfer blocks 112, 114.
The roller cutter assembly 26 is moved into and is removed out from
the cutter well from behind the cutterhead 20. FIG. 13 shows a
roller cutter assembly 26 spaced rearwardly from the rear portal of
its cutter well. When assembly 26 is moved forwardly into the well
the end portions 104, 106 enter via the avenues 108, 110. The
roller cutter assembly 26 is moved forwardly until the front ends
of the end members 104, 106 are against forward stops 111. Then,
load transferring blocks 112, 114 are moved through the rear portal
and into the channels 108, 110 (FIG. 12). Bolts 116 may be inserted
through openings 118 formed through the blocks 112, 114 and
threaded into openings 120 provided in the frame members 100, 102.
As will be appreciated, when the bolts 116 are tightened they will
draw the load transfer blocks 112, 114 into tight engagement with
load carrying surfaces which are the forwardly directed vertical
surfaces of channels 108, 110.
Such load carrying surfaces constitute surfaces on the cutterhead
frame since the end members 100, 102 are integral portions of the
cutterhead frame. Thus, thrust loads imposed on the cutting portion
of the roller cutter are transmitted in compression through the
load transfer blocks 112, 114 into the cutterhead frame.
Referring to FIG. 2, the cutterhead may be completed by adding
auxiliary frame members 126 (plates on edge) in a spaced
relationship to the frame members 50, 52, to define spaces
alongside of the inner spaces of the spokes which are very similar
to the inner spaces of the spokes for receiving additional roller
cutters. The cutterhead may also be provided with radially
elongated scoops 128 and a plate metal facing around the scoops and
inbetween the radial beams 48. As shown by FIG. 2, the scoops have
inlets for the mined material which commence adjacent the hub 32
and extend out to the periphery of the cutterhead.
During tunneling the collector 74 at the forward end of the
conveyor 72 is positioned relatively close behind the center cutter
assembly 28. The cuttings picked up by the scoops 128 drop into the
collector 74. They fall onto the conveyor belt 130 and are carried
thereby to a system of additional conveyors and/or material carts
which remove the mined material out from the tunnel in one of a
number of known ways, none of which constitute a part of the
present invention.
According to an aspect of the invention, however, provision is made
for retracting the collector so that access may be had to the inner
space IS of the cutterhead, for the purpose of replacing cutters.
One way of moving the conveyor out of the way would be to construct
the conveyor so that it could be retracted in total from its
operative position. The rear end of the conveyor is mounted on
wheels or the like, and the front end of the conveyor is normally
connected to the cutterhead support 10. In preparation to replace a
cutter the front end of the conveyor could be disconnected from the
cutterhead support, and then the conveyor could be forced
rearwardly. The cutterhead support could be provided with some sort
of bearing arrangement to support the front end portion of the
conveyor for sliding movement. However, it is presently
contemplated that the forward frame portion of the cutterhead,
which includes the material collector 74 and a forward pulley 132
on which the conveyor belt reverses its direction, are mounted to
be movable relative to both the cutterhead support 10 and the rest
of the conveyor. As shown by FIGS. 14 and 15, a pair of tracks 134,
136 may be provided to extend axially of the tunnel on opposite
sides of the conveyor 72. A front end carriage 138 may be mounted
for axial movement in the tunnel by means of rollers 140 which are
engaged by the tracks 134, 136. The front end portion of the
conveyor frame, including the material collector 74 and the front
roller 132 are carried by the carriage 138. The carriage 138 may be
controlled in position by means of one or more hydraulic cylinders
142 (FIG. 14) which extend axially of the tunnel and are connected
at their forward ends to the carriage 138 and at their rearward
ends to a portion of the cutterhead support 10. The cylinders 142
are extended for the purpose of moving the collector into the
material collecting position relative to the cutterhead. When in
this position, the conveyor belt 130 is tightened. The cylinders
142 may be retracted for the purpose of moving the front portion of
the conveyor rearwardly an amount sufficient to create sufficient
working room within the inner space IS of the cutterhead (FIG. 14).
Retraction of the cylinders 142 causes them to move the forward
frame portion of the conveyor belt rearwardly, relative to both the
cutterhead and the conveyor belt. The thus slackened forward end
portion of the conveyor belt is then merely folded out of the way,
so that it will not interfere with cutter removal and installation
work within the inner space IS. Of course, the manner of moving the
forward end portion of the conveyor 72 out from the inner space IS
could be accomplished in any one of a number of other ways, as
well.
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