GB2174739A - Rotary soil/rock boring head - Google Patents

Abstract

A rotary boring head having a body (1) with flushing agent holes (2) and toolbit mounts (4) at its front or working face (3), and in which the flushing agent holes lead to flushing agent escape bores (7) which open at the front faces (8) of the mounts, is characterised in that each flushing agent escape bore opens in a crest area of the front face of its mount and behind the toolbit in relation to the direction of rotation of the head, so that the mouths of the flushing agent escape bores are disposed effectively in the lee of the toolbits and hence of the debris, so that it is impossible to block the flushing agent escape bores and/or their mouths. <IMAGE>

Description

SPECIFICATION Rotary soil/rock boring head This invention relates to a rotary head for boring into soil and/or rock, having a body with flushing agent holes and tool bits inserted in mounts at its front or working face, (i.e., which faces the soil and/ or rock), in which the flushing agent holes open into the mounts and the mounts have flushing agent escape bores which communicate with the flushing agent holes and open at the front faces of the mounts.

There are known rotary heads of this type, in which the escaping flushing agent is used on the one hand to cool the mounts and/or their toolbits and on the other hand to flush away the boring debris and fines which accumulate between the rock face and the front face of the body. However, the flushing action of these known rotary heads is often unsatisfactory, since the mouths of the flushing agent escape bores are disposed ahead of the toolbits in relation to the direction of head rotation and moreover overhung by the tool bits. This results in frequent blockages of the flushing agent escape bores, particularly when working into soft material, whereby the cooling and flushing actions are reduced almost to zero.This in turn leads to the premature abrasive failure of the mounts and/or theirtoolbits (cf US-PS 4303 136). Similar criticisms apply to a known boring crown in which nozzles are inserted into the mouths of the flushing agent escape bores, which mouths are moreover similarly disposed ahead of the toolbits in relation to the direction of crown rotation and underneath the tool bits (cf. DE-OS 28 21 307).

It is known in a different field of technology, viz., with coal picks and cutters, to allow the flushing agent escape bores to terminate behind the tool bits in relation to the working direction, so as to attain both cooling and flushing effects. However, the mouths are once again overhung by the tool bits in this case (cf. Tunnels & unnelling, October 1983, p. 52). These known means have not significantly influenced the problems of the blockage of flushing agent channels and the resulting loss of cooling and flushing action in rotary boring heads.

The object of the invention is to provide a rotary head of the type initially described, in which it is impossible to block the flushing agent escape bores and/or their mouths, so that in this respect the flushing and cooling action is permanently optimised.

According to the present invention a rotary head of the type initially described is characterised in that each flushing agent escape bore opens in a crest area of the front face of its mount and behind the toolbit in relation to the direction of head rotation.

Accordingly, the mouths of the flushing agent escape bores are disposed effectively in the lee of the tool bits and hence of the debris, so that it is impossible to block the flushing agent escape bores and/or their mouths. These features of the invention also attain as it were a wing-like spread of the flushing action over the flanks of the mounts. In this respect, therefore, the flushing effect and hence the cooling effect are optimised in the device of the invention. Furthermore, the cooling effect is also optimised because the flushing agent no longer escapes near the base of the mounts in the rotary head of the invention; it escapes into the crest areas, in the lee of the toolbits, so that their cutting edges are cooled directly and the removal of debris is accelerated.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a front elevation of a rotary boring head in accordance with the invention; Figure 2 is a fragmentary section, on the line A-B, of Figure 1; and Figure 3 is a side elevation, partly in section on the line C-D, of the head shown in Figure 1,with the mounts removed.

In the drawings, a rotary head for boring into soil and/or rock has a body 1 with flushing agent holes 2 and mounts 4 at its front or working face (i.e., which faces the soil and/or rock). Toolbits 5 are inserted in the mounts 4. The flushing agent holes 2 diverge from a central bore 6 and lead to the mounts 4. The mounts 4 have flushing agent escape bores 7, which communicate with the flushing agent holes 2 and open at the front of the faces 8 of the mounts.

In accordance with the invention, each flushing agent escape hole 7 opens in a crest area of the front face 8 of its mount 4 and behind the toolbit 5 in relation to the direction of rotation of the head thus the bores 7 are disposed as it were in the lee of the toolbits 5, so that it is impossible for them to become blocked by debris. The body has blind holes 9 into which the mounts 4 are inserted and secured, for example by welding. These blind holes 9 have connecting ducts 10 in their base areas, communicating with the flushing agent holes 2, so that although no sealing means are used the flushing agent can escape satisfactorily in the region of all the mounts 4 and toolbits 5. The flushing action has a wing-like spread over the flanks of the mounts, whereby the flushing effect and hence the cooling effect are optimised.

At least one additional flushing agent hole 12 can open in known manner at the front face 3 of the body.

1. A rotary head for boring into soil and/or rock, having a body with flushing agent holes and tool bits inserted in mounts at its front or working face, in which the flushing agent holes open into the mounts and the mounts have flushing agent escape bores which communicate with the flushing agent holes and open at the working faces of the mounts, characterised in that each flushing agent escape bore opens in a crest area of the front face of its mount and behind the toolbit in relation to the direction of rotation of the head.

2. A rotary boring head as in Claim 1, wherein the body has blind holes for the insertion of the mounts,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Rotary soil/rock boring head This invention relates to a rotary head for boring into soil and/or rock, having a body with flushing agent holes and tool bits inserted in mounts at its front or working face, (i.e., which faces the soil and/ or rock), in which the flushing agent holes open into the mounts and the mounts have flushing agent escape bores which communicate with the flushing agent holes and open at the front faces of the mounts. There are known rotary heads of this type, in which the escaping flushing agent is used on the one hand to cool the mounts and/or their toolbits and on the other hand to flush away the boring debris and fines which accumulate between the rock face and the front face of the body. However, the flushing action of these known rotary heads is often unsatisfactory, since the mouths of the flushing agent escape bores are disposed ahead of the toolbits in relation to the direction of head rotation and moreover overhung by the tool bits. This results in frequent blockages of the flushing agent escape bores, particularly when working into soft material, whereby the cooling and flushing actions are reduced almost to zero.This in turn leads to the premature abrasive failure of the mounts and/or theirtoolbits (cf US-PS 4303 136). Similar criticisms apply to a known boring crown in which nozzles are inserted into the mouths of the flushing agent escape bores, which mouths are moreover similarly disposed ahead of the toolbits in relation to the direction of crown rotation and underneath the tool bits (cf. DE-OS 28 21 307). It is known in a different field of technology, viz., with coal picks and cutters, to allow the flushing agent escape bores to terminate behind the tool bits in relation to the working direction, so as to attain both cooling and flushing effects. However, the mouths are once again overhung by the tool bits in this case (cf. Tunnels & unnelling, October 1983, p. 52). These known means have not significantly influenced the problems of the blockage of flushing agent channels and the resulting loss of cooling and flushing action in rotary boring heads. The object of the invention is to provide a rotary head of the type initially described, in which it is impossible to block the flushing agent escape bores and/or their mouths, so that in this respect the flushing and cooling action is permanently optimised. According to the present invention a rotary head of the type initially described is characterised in that each flushing agent escape bore opens in a crest area of the front face of its mount and behind the toolbit in relation to the direction of head rotation. Accordingly, the mouths of the flushing agent escape bores are disposed effectively in the lee of the tool bits and hence of the debris, so that it is impossible to block the flushing agent escape bores and/or their mouths. These features of the invention also attain as it were a wing-like spread of the flushing action over the flanks of the mounts. In this respect, therefore, the flushing effect and hence the cooling effect are optimised in the device of the invention. Furthermore, the cooling effect is also optimised because the flushing agent no longer escapes near the base of the mounts in the rotary head of the invention; it escapes into the crest areas, in the lee of the toolbits, so that their cutting edges are cooled directly and the removal of debris is accelerated. An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a front elevation of a rotary boring head in accordance with the invention; Figure 2 is a fragmentary section, on the line A-B, of Figure 1; and Figure 3 is a side elevation, partly in section on the line C-D, of the head shown in Figure 1,with the mounts removed. In the drawings, a rotary head for boring into soil and/or rock has a body 1 with flushing agent holes 2 and mounts 4 at its front or working face (i.e., which faces the soil and/or rock). Toolbits 5 are inserted in the mounts 4. The flushing agent holes 2 diverge from a central bore 6 and lead to the mounts 4. The mounts 4 have flushing agent escape bores 7, which communicate with the flushing agent holes 2 and open at the front of the faces 8 of the mounts. In accordance with the invention, each flushing agent escape hole 7 opens in a crest area of the front face 8 of its mount 4 and behind the toolbit 5 in relation to the direction of rotation of the head thus the bores 7 are disposed as it were in the lee of the toolbits 5, so that it is impossible for them to become blocked by debris. The body has blind holes 9 into which the mounts 4 are inserted and secured, for example by welding. These blind holes 9 have connecting ducts 10 in their base areas, communicating with the flushing agent holes 2, so that although no sealing means are used the flushing agent can escape satisfactorily in the region of all the mounts 4 and toolbits 5. The flushing action has a wing-like spread over the flanks of the mounts, whereby the flushing effect and hence the cooling effect are optimised. At least one additional flushing agent hole 12 can open in known manner at the front face 3 of the body. CLAIMS

1. A rotary head for boring into soil and/or rock, having a body with flushing agent holes and tool bits inserted in mounts at its front or working face, in which the flushing agent holes open into the mounts and the mounts have flushing agent escape bores which communicate with the flushing agent holes and open at the working faces of the mounts, characterised in that each flushing agent escape bore opens in a crest area of the front face of its mount and behind the toolbit in relation to the direction of rotation of the head.

2. A rotary boring head as in Claim 1, wherein the body has blind holes for the insertion of the mounts, and characterised in that the blind holes have connecting ducts in their base areas communicating with the flushing agent holes.

3. A rotary head for boring into soil and/or rock substantially as hereinbefore described with reference to the accompanying drawings.