GB2135366A

GB2135366A - Excavating machine

Info

Publication number: GB2135366A
Application number: GB08334322A
Authority: GB
Inventors: Hirose Takada; Juichi Asano; Hiroshi Saito; Shigeru Harada
Original assignee: Komatsu Ltd
Current assignee: Komatsu Ltd
Priority date: 1982-12-23
Filing date: 1983-12-23
Publication date: 1984-08-30
Also published as: FR2538445B1; FR2538445A1; GB8334322D0; GB2135366B; DE3346422A1

Abstract

An excavating machine is described which is suitable for use in the laying of pipelines underground. Pebbles are crushed between uniformly spaced rotary teeth (4a) provided on the rear face of a disc-shaped rotatable cutter head (3) of the machine and stator teeth (4b) provided at uniform intervals spaced from each other on the front surface of an annular front face plate (1a) of the body of the machine confronting the rear face of the cutter head. In the illustrated embodiments water is supplied to allow earth, sand and crushed pebbles to be removed as a slurry. <IMAGE>

Description

SPECIFICATION Excavating machine This invention relates to excavating machines and more particularly to such machines suitable for use in the laying of pipelines underground.

Machines have previously been proposed by which pipelines are laid underground. Earth and sand is excavated in advance of a pipeline by means of a pilot excavator device connected to the leading end of the length of pipe to be laid underground and advanced by means of a pipe propelling machine located in a launching pit at the rear. Excavated earth and sand is removed as a slurry by supplying water from a pump via the buried pipeline into the pilot excavating machine.

The slurry is discharged by a sand pump through a slurry pipeline also installed in the buried pipeline.

Stones and pebbles (hereinafter generally referred to as "pebbles") which may be mixed in the slurry have proved to be a serious problem. In general, there is an upper limit in the size of stones which can be removed in the slurry, this upper limit being between one third and one half of the slurry discharge pathway (that is the slurry pipeline, the sand pump, etc.). With the prior proposed apparatus, it was thus necessary to select the size of intake port in the cutter head of a pilot excavator device intended to receive excavated earth and sand in terms of the diameter of the discharge pipe in order that pebbles could be removed in the slurry. The previously proposed machines could not be used in ground containing pebbles larger than the earth and sand intake port in the cutter head. We found this to prove an important restriction in the utility of such machines.

In accordance with a first aspect of the present invention there is provided an excavating machine suitable for use in the laying of pipes underground, comprising: a disc-shaped rotable cutter head having a plurality of excavating bits and a plurality of excavated earth and sand intake ports and adapted to be mounted on the leading end of the body of a pilot excavator device arranged to be propelled underground ahead of a pipeline to be laid underground; a plurality of rotary teeth formed integrally on the rear face of the said cutter head and extending generally radially at uniform intervals spaced apart from one another; an annula front face plate for said pilot excavator body located adjacent and opposite to said cutter head and having a plurality of passage holes for excavated earth and sand and arranged for communication with the inside of said pilot excavator device body; and a plurality of stator teeth formed integrally on the front surface of the front face plate spaced apart from one another at uniform intervals, said rotary teeth and said stator teeth forming in combination a pebble crusher device.

According to a second and alternative aspect of the present invention, we provide an excavating machine suitable for use in the laying of pipelines, the machine incorporating a pebble crusher device comprising a plurality of uniformly spaced rotary teeth provided on the rear face of a disc-shaped rotable cutter head of the machine and a plurality of stator teeth provided at uniform intervals spaced from each other on the front surface of an annular front face plate of the body of the machine confronting the rear face of the cutter head.

Preferably the machine includes a device for ejecting water onto the front surface of the front face plate to prevent stone dust produced when crushing pebbles from accumulating in the respective spaces between the stator teeth and clogging the excavated earth and sand passage holes.

The invention is hereinafter more particularly described by way of example only with reference to the accompanying drawings in which: Fig. 1 is a fragmentary longitudinal schematic sectional view showing an embodiment of excavating machine according to the present invention; Fig. 2 is a front view of a cutter head adapted to be mounted on the leading end of the excavating machine of Fig. 1; Fig. 3 is a fragmentary schematic longitudinal sectional view showing one embodiment of water ejector device in an excavating machine constructed according to the present invention; Fig. 4 is a front view of the front face plate of the machine shown in Fig. 3; Pig. 5 is a fragmentary schematic longitudinal sectional view showing another embodiment of water ejector device in an excavating machine constructed according to the present invention; and Fig. 6 is a front view of the front face plate of the machine shown in Fig. 5.

In Fig. 1 the body of a pilot excavator device of the excavating machine is shown at 1. The pilot excavator device is adapted to be propelled, while excavating the ground, ahead of a pipeline (not shown). Mounted on the leading end of the body 1 is a cutter head 3 which projects from the body 1 and is adapted to be rotated by a rotating prime mover 2. Further, the excavating device body 1 has formed therein a water supply passage 1 d and a passage 1 g for the discharge of the resulting slurry of excavated earth and sand for rearward transport and discharge by means of a sand pump or the like to an appropriate place.

As shown in Fig. 2, the rotatable cutter head 3 has a plurality of fan or segment-shaped intake ports 3c formed therein for excavated earth and sand. Further, the cutter head 3 has a plurality of strip-shaped excavating bits 3b fixedly secured to the front surface thereof in parallel reiationship between the intake ports 3c. Further, the cutter 3 has a plurality of radially extending rod-shaped rotary teeth 4a formed as an integrai unit thereof on its rear surface spaced apart from one another at uniform intervals. The cutter head 3 can be attached and detached readily to allow for replacement when worn.

A front plate 1 a of the excavator device body 1 is disposed adjacent and opposite to the cutter head and consists of an annular plate having a relatively large hole 4c formed in the central part thereof to allow passage of a cutter head rotating shaft 3a therethrough, and a large number of small diameter, earth and sand passage holes 1 e extending from the front surface to the rear surface of the plate for passing excavated earth and sand as a slurry into the excavator device body 1. This annular front face plate 1 a has a plurality of rod-shaped stator teeth 4b formed as an integral unit thereof on its front surface at uniform intervals in the outer circumference thereof, the teeth 4b extending generally tangentially of the inner circumference of the plate. Thus, the rotary teeth 4a and the stator teeth 4b form a pebble crusher device 4 in combination.

Figs. 3 and 4 show one embodiment of water ejector device for washing away stone dust produced when crushing pebbles to prevent the dust from accumulating between the stator teeth adjacent and clogging the earth and sand passage holes 1 e. In this embodiment, a plurality of nozzles 5 are formed in the front face plate 1 a, penetrating from its rear surface to its front surface. These nozzles 5 are each located in the space between a pair of adjacent stator teeth 4b, 4b. Branch conduits 1 C connect these nozzles 5 with the aforementioned water supply passage 1 d.

Figs. 5 and 6 illustrate another embodiment of water ejector device. In this embodiment, an annular tubular member 1 b is provided on the inner circumferential surface of the annular front face plate 1 a. Formed in the tubular member 1 b is an annular water passage 1 fwhich is connected through the branch conduits 1 C with the water supply passage 1 d. Further, a plurality of through holes 5a are provided along the outer circumference of the tubular member 1 b, one between each pair of adjacent stator teeth 4b, 4b.

These holes 5a are connected to the annular water passage lfand have nozzles 5 screwed therein for ejecting water radially along the stator teeth 4b (as shown by arrows in Fig. 6).

The operation of the excavating machine constructed as mentioned above will now be described below.

The whole of earth and sand excavated by the cutter head 3 rotated by prime mover 2 is taken through the excavated earth and sand intake ports 3c into the pebble crusher device 4. Granular earth and sand pass directly through the earth and sand passage holes 1 e in the front face plate 1 a into the pilot excavator device body 1, and are changed into slurry state with water introduced by way of the water supply passage 1 d so as to be discharged through the earth and sand discharge passage 1 g. Large pebbles which cannot pass through the earth and sand passage holes 1 e are carried into the spaces defined by the adjacent rotary teeth 4a and stator teeth 4b and are crushed. The crushed pebbles will pass through the earth and sand passage holes 1 e and the rotating shaft insertion hole 4c into the excavating device body 1.

Further, water is continuously ejected by the nozzles 5 in order to prevent stone dust produced when crushing pebbles from accumulating between the stator teeth and clogging the earth and sand passage holes 1 e.

Although, in the embodiments shown, the stator teeth 4b are formed as a plurality of tangentially extending projections surrounding the opening 4c for the rotable shaft, other configurations are possible.

Claims

1. An excavating machine suitable for use in the laying of pipes underground, comprising: a discshaped rotable cutter head having a plurality of excavating bits and a plurality of excavated earth and sand intake ports and adapted to be mounted on the leading end of the body of a pilot excavator device arranged to be propelled underground ahead of a pipeline to be laid underground; a plurality of rotary teeth formed integrally on the rear face of the said cutter head and extending generally radially at uniform intervals spaced apart from one another; an annular front face plate for said pilot excavator body located adjacent and opposite to said cutter head and having a plurality of passage holes for excavated earth and sand and arranged for communication with the inside of said pilot excavator device body; and a plurality of stator teeth formed integrally on the front surface of the front face plate spaced apart from one another at uniform intervals, said rotary teeth and said stator teeth forming in combination a pebble crusher device.

2. A machine as claimed in Claim 1, further comprising a device for ejecting water on to the front surface of the front face plate to prevent stone dust produced when crushing pebbles from accumulating in the respective spaces between the stator teeth and clogging said excavated earth and sand passage holes.

3. A machine as claimed in Claim 2, wherein said water ejecting device comprises: a plurality of nozzles, each extending from the rear surface of said front face plate to the front surface thereof and each being disposed between a respective pair of stator teeth; and a branch conduit means coupled to said nozzles for connecting said nozzles to a water supply passage provided inside said pilot excavator device body.

4. A machine as claimed in Claim 2, wherein said water ejecting device comprises: nozzle means adapted to eject water along and between the stator teeth; and conduit means coupled to said nozzle means for connecting said nozzle means to a water supply passage provided inside said pilot excavator device body.

5. A machine according to any preceding claim, wherein said stator teeth are generally rod-shape and extend at uniform intervals generally tangentially from the inner circumference of the annular front face plate.

6. An excavating machine suitable for use in the laying of pipelines, the machine incorporating a pebble crusher device comprising a plurality of uniformly spaced rotary teeth provided on the rear face of a disc-shaped rotable cutter head of the machine and a plurality of stator teeth provided at uniform intervals spaced from each other on the front surface of an annular front face plate of the body of the machine confronting the rear face of the cutter head.

7. Suitable for use in the laying of pipes underground, an excavating machine substantially as hereinbefore described with reference to and as shown in the accompanying drawings.