Patent Description:
<CIT> discloses a cylindrical tunnel excavator having a cutter face on the front end of a main body portion. The objective of this invention is to provide a tunnel excavator capable of excavating the ground efficiently by making the shear stress of the cutter face uniform or close thereto. The front cutter face is formed in a conical shape whose centre is recessed rearward, so that the shear stress generated on the inner peripheral surface of the inverted conical cutter face has a constant value, regardless of the radial position along the cutter face.

<CIT>_discloses an earth boring machine having a plurality of cutting disks having wedge form peripheries, which are moved while being held against the working face under great pressure in concentric paths over the working face. The cutting disks are axially located on a cutter head in different planes so that the working face is of a cone-like configuration with the conical surfaces being desirably quite steep. Each cutter disk follows in succession the cut made by the next cutter inwardly and downwardly and works to break away an area which has lost its lateral support on the downhill side by the action of the cutter ahead, which is one increment inwardly and downwardly toward the center.

<CIT> discloses a drill bit comprising a disc-shaped cutter disc, the lower part of the cutter disc having a concave cavity, wherein cutting teeth are arranged on the inner wall of the cavity, and wherein the central axis of the cavity coincides with the central axis of the cutter disc.

According to the invention there is provided a cutter head arrangement for a shaft boring machine as defined in claim <NUM>.

According to claim <NUM>, the conical body of the recessed wall portion defines a conical recess (proximate a central region of the cutter head portion, at a distal end of the cutter head portion). The conical body accordingly defines an inwardly extending apex that terminates substantially in line with a central axis of the cutter head portion.

In an embodiment, the cutter elements may be arranged concentrically and/or radially on the conical body
In an embodiment, the cutter head side wall is substantially cylindrical and the cutter head portion includes a tapering peripheral wall that extends between (the distal end of) the cutter head side wall and the rim portion, with the rim portion accordingly protruding from the cutter head side wall, so that the rim portion defines a circular rim portion. In an embodiment, the tapering peripheral wall may also be fitted with cutter elements.

Advantageously, the cutter elements may be installed and replaced either from the front or the rear of (i.e. from within the chamber of) the cutter head portion.

In an embodiment, the cutter head arrangement comprises a connector portion extending from (a proximal end of) the cutter head side wall to enable the cutter head arrangement to be secured to a boring machine, such as a blind shaft boring machine, if required. Thus, in one version, the cutter head arrangement is part of a larger boring machine. However, in another version, the cutter head arrangement can be used on its own without the need for it to be connected to a boring machine. The size of the cutter head portion can also change according to requirements and is not limited to any particular size.

The connector portion includes a (substantially cylindrical) connector head side wall extending from the cutter head side wall, with an end wall extending across a (proximal) end of the connector head side wall, the end wall defining a substantially central connector aperture therein.

In an embodiment, the cutter head side wall is enlarged relative to the connector head side wall, with a step accordingly being defined between the cutter head side wall and the connector head side wall.

In an embodiment, the cutter elements are fitted on or proximate the rim portion and the inwardly extending conical body and the tapering peripheral wall.

Advantageously, the distance from the cutter head portion to the cutting face is spaced to ensure that the material that is being cut/bored is of a predetermined size. This spacing, together with the spacing of the cutter elements and the number of cutter elements, is used to predetermine the size of particle/material cuttings. This combination of factors acts as a sizing guide or arrangement to enable the particle or material size to be controlled, to ultimately ensure that the cutter head suction pipe does not become blocked by overly sized particles.

In an embodiment, a cutter element is provided in front of the material handling aperture to ensure that the material that moves through the material handling aperture is an appropriate size to prevent blockages.

In an embodiment, the conical body of the recessed wall portion extends away from the rim portion at an angle of <NUM>° into the chamber.

In an embodiment, scraper elements can be fitted to the cutter head portion to encourage movement of cuttings to the material handling aperture/s. The scraper elements can be replaced as needed.

The invention will now be further described, by way of example, with reference to the accompanying diagrammatic drawings.

Referring first to <FIG>, a cutter head arrangement <NUM> according to one version/application of the invention is shown. In this version/application, the cutter head arrangement <NUM> comprises a rear connector portion <NUM> to enable the cutter head arrangement <NUM> to be secured to a boring machine <NUM> (shown in <FIG>), such as a blind shaft boring machine. Thus, in one version, the cutter head arrangement <NUM> is part of a larger boring machine <NUM>. However, in another version, the cutter head arrangement <NUM> can be used on its own, as an individual piece of equipment, without the need for it to be connected to a boring machine.

The cutter head arrangement <NUM> defines a pilot shaft cutter head of the shaft boring machine <NUM>. A pilot shaft main drive <NUM> is provided to rotatingly drive the cutter head arrangement <NUM> relative to the boring machine <NUM>. In one application, as shown in <FIG>, the shaft boring machine <NUM> is part of a larger shaft boring system <NUM>, of the type disclosed in <CIT> and <CIT>. The shaft boring machine <NUM> includes a reamer cutter head <NUM> driven by a reamer main drive <NUM> to ream the main, enlarged shaft. The cutter head arrangement <NUM> extends from the lowermost end of the shaft boring machine <NUM> to blind bore a pilot hole, in use.

The size of the cutter head arrangement <NUM> can also change according to requirements and is not limited to any particular size.

A front cutter head portion <NUM> extends from the rear connector portion <NUM>. The cutter head portion <NUM> includes a substantially cylindrical cutter head side wall <NUM> to define a chamber or cavity <NUM>, as best shown in <FIG> and <FIG>, surrounded by the cutter head side wall <NUM>. The connector portion <NUM> extends from a proximal end of the cutter head side wall <NUM>.

The connector portion <NUM> includes a substantially cylindrical connector head side wall <NUM> extending from the cutter head side wall <NUM>. An end wall <NUM> extends across a proximal end of the connector head side wall <NUM>, the end wall <NUM> defining a substantially central connector aperture <NUM> therein to facilitate the fitting of the cutter head arrangement <NUM> to the boring machine <NUM>.

In an embodiment, the cutter head side wall <NUM> is enlarged relative to the connector head side wall <NUM>, with a step <NUM> accordingly being defined between the cutter head side wall <NUM> and the connector head side wall <NUM>.

The front cutter head portion <NUM> includes a substantially circular rim portion <NUM> extending from a distal end of the cutter head side wall <NUM>. The rim portion <NUM> defines a working, contact face of the front cutter head portion <NUM>.

A recessed wall portion <NUM>, typically in the form of a conical body <NUM>, extends away from the rim portion <NUM> inwardly (at an angle of <NUM>°, for example, as best shown in <FIG>) into the chamber <NUM> so as to be surrounded by the cutter head side wall <NUM>. The conical body <NUM> thus defines a conical recess <NUM> proximate a central region of the cutter head portion <NUM>, at a distal end of the cutter head portion <NUM>, with the conical body <NUM> extending inwardly towards the interface <NUM> between the rear connector portion <NUM> and the front cutter head portion <NUM>.

As best shown in <FIG> and <FIG>, the conical body <NUM> accordingly defines an inwardly extending apex <NUM> that terminates substantially in line with a central axis <NUM> of the cutter head arrangement <NUM>.

In an embodiment, the cutter head portion <NUM> includes a tapering peripheral wall <NUM> that extends between the distal end of the cutter head side wall <NUM> and the rim portion <NUM>. The rim portion <NUM> accordingly protrudes from the cutter head side wall <NUM>, so that the rim portion <NUM> defines a circular ridge between the inwardly extending conical body <NUM> and the tapering peripheral wall <NUM>.

In an embodiment, a plurality of concentric and/or radial cutter elements <NUM>, <NUM>, <NUM> are fitted on or proximate the rim portion <NUM> and/or the inwardly extending conical portion <NUM> and/or the tapering peripheral wall <NUM>, respectively, to enable the cutter head portion <NUM> to blind bore a pilot hole, in use.

The cutter elements <NUM>, <NUM>, <NUM> can be installed either from the back of the cutter head portion <NUM> (i.e. from within the chamber or cavity <NUM>) or from the front. The cutter elements <NUM>, <NUM>, <NUM> are typically closed off with a cover element. This cover element can have an electronic device to measure certain parameters for example the wear of the cutter element <NUM>, <NUM>, <NUM> and the working temperature. A rotary swivel that is used in the cutter head portion <NUM> can be used to supply the cutter head portion <NUM> with required fluids for example but not limited to hydraulic fluid, water and cables that can be used for intelligence and or communication.

The rim portion <NUM> defines at least one material handling aperture <NUM> to accommodate a pilot shaft material handling arrangement <NUM>, which will be described in more detail further below, with reference to <FIG> and <FIG>. As best shown in <FIG> and <FIG>, the at least one material handling aperture <NUM> extends between the contact face of the rim portion <NUM> and the chamber <NUM> surrounded by the cutter head side wall <NUM>.

Advantageously, the distance from the cutter head portion <NUM> to the cutting face is spaced to ensure that the material that is being cut/bored is of a predetermined size. This spacing, together with the spacing of the cutter elements <NUM>, <NUM>, <NUM> and the number of cutter elements <NUM>, <NUM>, <NUM>, is used to predetermine the size of particle/material cuttings. This combination of factors acts as a sizing guide or arrangement to enable the particle or material size to be controlled, to ultimately ensure that a suction pipe <NUM> (described further below) does not become blocked by overly sized particles. To achieve this, in one version, a cutter element can be installed in front of the material handling aperture <NUM> to ensure that the material that is handled through the aperture <NUM> is an appropriate size to prevent blockages.

In an embodiment, scraper elements can be fitted to the cutter head portion <NUM> to encourage movement of cuttings to the material handling aperture/s <NUM>. The scraper elements can be replaced as needed.

Turning now to <FIG> and <FIG>, the pilot shaft material handling arrangement <NUM> comprises a cutter head suction pipe <NUM> extending from the material handling aperture <NUM>. The cutter head suction pipe <NUM> extends adjacent an inner face of the conical body <NUM> and then upwardly along the central axis of the cutter head portion <NUM>. The end of the cutter head suction pipe <NUM> protrudes from the central connector aperture <NUM> of the connector portion <NUM>.

In an embodiment, the end of the cutter head suction pipe <NUM> is fitted with a double walled swivel arrangement <NUM> that defines a first pipe <NUM> that is in communication with the cutter head suction pipe <NUM> and a second pipe <NUM> that leads into a cutter head blower pipe <NUM> that extends up to a vacuum unit <NUM> provided on an upper working stage of the shaft boring system <NUM>, as shown in <FIG>.

In an embodiment, the pilot shaft material handling arrangement <NUM> further comprises a kibble <NUM> that acts as a vacuum collector kibble that can be lowered through the shaft boring machine <NUM> and secured to the double walled swivel arrangement <NUM>. The kibble <NUM> includes a kibble suction pipe <NUM> that is secured to the other end of the first pipe <NUM> of the double walled swivel arrangement <NUM> so as to be in material communication with the cutter head suction pipe <NUM>. The swivel arrangement <NUM> allows material to be sucked away from the pilot hole being bored as the cutter head arrangement <NUM> rotates, via the cutter head suction pipe <NUM>, as indicated by arrows <NUM> in <FIG>. The material <NUM> accumulates within the relatively stationary kibble <NUM> via the kibble suction pipe <NUM>, via the double walled swivel arrangement <NUM>, as the cutter head arrangement <NUM> continues to rotate.

The kibble <NUM> further includes a kibble blower pipe <NUM> that is secured to the other end of the second pipe <NUM> of the double walled swivel arrangement <NUM> so as to be in fluid communication with the cutter head blower pipe <NUM>. The kibble blower pipe <NUM> directs air from an upper region of the kibble <NUM>, via the kibble blower pipe <NUM>, into the cutter head blower pipe <NUM>, via the second pipe <NUM> of the double walled swivel arrangement <NUM>, and then out to the vacuum unit <NUM>, as indicated by arrows <NUM>.

In an embodiment, an upper region of the kibble <NUM> includes a filtering arrangement <NUM> to filter the dust resulting from the material collecting within the kibble <NUM>. As a result, relatively clean air is conveyed through the kibble blower pipe <NUM> and then the cutter head blower pipe <NUM>, and then finally up to the vacuum unit <NUM>. Once the kibble <NUM> has collected sufficient material, the cutter head arrangement <NUM> stops rotating, to enable the kibble <NUM> to be hoisted up to surface where it will be emptied)
This material handling arrangement <NUM> ensures that the removal of material and related muck takes place very close to the wall being bored, which results in an extremely efficient machine.

Claim 1:
A cutter head arrangement (<NUM>) for fitting to a shaft boring machine (<NUM>) for blind shaft boring and enlargement applications, the cutter head arrangement (<NUM>) comprising:
a cutter head portion (<NUM>) including a cutter head side wall (<NUM>) to define a chamber (<NUM>) surrounded by the cutter head side wall (<NUM>), characterised in that
a rim portion (<NUM>) extends from the cutter head side wall (<NUM>), the rim portion (<NUM>) defining a working, contact face of the cutter head portion (<NUM>), the rim portion (<NUM>) defining at least one material handling aperture (<NUM>) to accommodate a pilot shaft material handling arrangement (<NUM>), the at least one material handling aperture (<NUM>) extending between the contact face of the cutter head portion (<NUM>) and the chamber (<NUM>) surrounded by the cutter head side wall (<NUM>); and
a recessed wall portion (<NUM>) extends away from the rim portion (<NUM>) inwardly into the chamber (<NUM>) so as to be surrounded by the cutter head side wall (<NUM>), with the rim portion (<NUM>) and/or the recessed wall portion (<NUM>) being fitted with a plurality of cutter elements (<NUM>, <NUM>, <NUM>) to enable the cutter head portion (<NUM>) to bore a pilot hole in use; wherein the recessed wall portion (<NUM>) is a substantially conical body (<NUM>) so as to define a conical recess (<NUM>) proximate a central region of the cutter head portion (<NUM>), at a distal end of the cutter head portion (<NUM>), with the conical body (<NUM>) accordingly defining an inwardly extending apex (<NUM>) that terminates substantially in line with a central axis (<NUM>) of the cutter head portion (<NUM>).