GB2352461A

GB2352461A - Ground cutting tool

Info

Publication number: GB2352461A
Application number: GB0016499A
Authority: GB
Inventors: Michael Gordon Bennett; David Roberson Donaldson
Original assignee: David Robertson Donaldson
Current assignee: David Robertson Donaldson
Priority date: 1999-07-06
Filing date: 2000-07-05
Publication date: 2001-01-31
Anticipated expiration: 2020-07-05
Also published as: GB0016499D0; GB2352461B8; GB2352461B; GB9915687D0; GB2352461A8

Abstract

A ground cutting device which may be used within a ground support shield (16) or supported from permanent ground support means, has one or more cutting tools (13) each mounted on an arm (6) capable of being manipulated by mechanical means (8, 10) in relation to a carrier plate (4). The plate is supported on a base unit 2 so that it can move axially and rotate. Bracing arms (1) suspend the plate (4) and its tools thus to be capable of automatic excavation without human intervention. The device is compact and portable thus to be readily deployed at a cutting face. If required means (17, 19, 20) Fig 3 may be provided to enable the device to be advanced mechanically as excavation proceeds and the device is configured and constructed to enable easy removal of spoil from the invert adjacent the cut face.

Description

2352461 A GROUND CUTTING TOOL THIS INVENTION concerns ground cutting

tools.

There are situations, for example when using ground support means, when it is required, for economical or practical reasons, to carry out excavation of the ground by hand. In order to facilitate this activity percussive hand held tools are often used. One type of such a tool is known as a pneumatic pick or colloquially a jigger pick. Continual use of such tools can cause Hand Arm Vibration Syndrome (HAVS) and Vibration White Finger (VWF).

This invention enables existing standard, or purpose made, percussive tools, to be used when excavating ground within a ground support means without the need to involve a human operator, and with a lightweight mechanical means which can be carried and assembled manually. The maximum weight which can be carried by a single person is 25 kg.

This invention is not limited to its use within ground support means such as a shield since it can be used when constructing an excavation which does not require a ground support shield. For instance, the invention can be supported from permanent ground support means. It can also be reconfigured, for instance by providing a suitable support means, to work in any environment requiring the use of hand held tools. Nor is the invention limited to the use -2of percussive tools since the means of excavation of the material of the face need not be percussive. Furthermore, greater forces can be imparted to the cutting pick or picks than can be applied by a hand held tool.

According to the present invention, there is provided, a ground cutting device comprising at least one cutting tool mounted on a frame for manipulation of the tool the frame being mounted on a base unit; means for advancing the tool towards a ground face to be cut; and at least one bracing member supporting the base unit rigidly with respect to the ground to be cut.

The bracing member may comprise a framework of arms suspending the base unit from a ground support shield or permanent ground support means.

The frame may be mounted on the base unit thus to be advanced with respect thereto towards the ground face to be cut.

The frame may be mounted on the base unit for rotation relative thereto thus to manoeuver the tool about the axis of rotation.

A plurality of tools may be mounted on the frame each by way of an arm about which the tool may be articulated.

The device may be operated automatically by computer controlled means. The frame may be parked on the base unit thus to provide free access beneath same for removal of excavated ground material.

The device may include ground support means movable to enable the base unit and frame to be advanced forwardly as the ground is excavated.

The frame may be movable selectively in opposite directions relative to the base unit thus to advance and retract the tool from the ground face to be cut.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:- Fig. 1 is an elevation showing a ground cutting device made in accordance with the first embodiment and mounted with respect to an existing ground support shield; Fig. 2 is an end view taken in the direction of arrow A in Fig. 1; but with the device in a "parked" condition; Fig. 3 is a view similar to Fig. I of a second embodiment of the invention; and Fig. 4 is a view similar to Fig. 2 and taken in the direction of arrow B in Fig. 3.

For the purpose of illustration, we describe one embodiment of the invention as it might be used for excavating ground when constructing a tunnel by means of a ground support means known as a hand shield, having an open face or when attached to a permanent lining. The shield can be fitted with hinged and or removable plates so as to provide additional ground support at the face.

Referring now to Fig. 1, four or more support arms 1, are hingedly attached to the inner wall of a cylindrical shield 16. A base unit 2 is attached to the inner ends of the support arms 1 and incorporates a slideway 3 which, in this embodiment, is a tube sliding within a tube, and allows a carrier plate 4, attached to it, to be moved backwards and forwards so as to force one or more tools into the face being excavated. The direction of movement is not limited to being exactly parallel to the axis of the shield 16. The moving part of the base unit 2 holding the carrier plate 4 can be moved along the slide-way 3 by means of a fluid or electrically powered ram or actuator. In this embodiment the actuator is a two-ended ram 5 which forms part of the slideway 3. The carrier unit 4 has one or cranked more arms 6 pivotally attached to it. In this embodiment there are two arms.

The carrier unit 4 may be rotated by an actuator 7 acting upon a rack 18 or levers or by a rotary means. In this embodiment a fluid motor is used. In a configuration where more than one arm 6 is attached to the carrier plate 4, such that most of the face to be excavated can be reached without rotation of the carrier plate 4, then the rotation actuator 7 can be dispensed with. The arm or arms 6 can be articulated relative to the carrier unit 4 by means of -5actuators 8. The shape of the carrier unit 4 depends upon the number of arms 6 attached to it but it is designed to be of minimum weight. A tool holder 9 is attached to each arms. Each of the tool holders 9 can be articulated relative to the arm which supports it by means of an actuator 10. The material or materials, from which the base unit 2, carrier plate 4, arms 6 and tool holders 9 are made, can be such as to be of minimum weight commensurate with adequate strength. A tool 11 is fitted to each of the tool holders 9, by means of a quick release clamp 12. A removable cutting pick 13 is retained by the tool 11. The cutting end of the pick 13 can be of any shape which is best suited to the type of ground being excavated. The device is connected to an external source of electrical and fluid power. Operation of the device can be controlled either from a control panel 14, mounted on a fixed part of the base unit 2, and or by a pendant control and or by a remote control panel.

The sequence of operation when excavating the face of material 15 can be controlled entirely manually or can be a combination of manual and automated computer control. The degree of automation will depend upon the desired cycle of excavation related to the means for removal of the excavated material and its disposal and any ground support operation carried out behind the advancing shield. Software programmes can be provided which easily allow the operator to alter the cycle to suit specific requirements. Shock absorber means can be fitted so as to reduce dynamic stresses in the component parts of the device.

Fig. 2 shows the arms parked. When it is required to remove excavated material from the invert of the shield adjacent to the face, the carrier plate 4, the arms 6 and the tool holders 9 can be parked in such a way as to maximise the available space beneath them. This -6condition can be seen in Fig. 2. In a semi-automatic mode the optimum parking position will be selected automatically.

Referring now to Figs. 3 and 4, in a second embodiment the ground cutting device is adapted for use where no existing shield 16 is present. In this case, an annular support member 17 comprises upper and lower segments 17a, 17b held apart by a pair of rams 18. The device is suspended from the upper segment 17a and thus held rigidly within the lining 22 of the tunnel by expansion of the rams 18.

An anchor ring 20 also comprises upper and lower segments held apart by two rams 21. The anchor ring enables the support ring to be moved forwardly, the two rings acting together so as to "walk" the device forwards when required.

This movement is carried out by initially extending the rams 21 to hold the anchor ring 20 rigidly within the lining 22 whereupon the two rams 18 are partially retracted so as to release the support ring 17 from the lining 22. Four horizontally disposed rams 19 are located between support ring 17 and anchor ring 20, and these are extended to move the support ring 17 forwardly by a distance equivalent to the stroke of the rams 19. The rams 18 are then expanded to hold the support ring 17 rigidly within the lining 22 and the rams 21 are partially retracted so as to release the anchor ring 20 whereupon rams 19 are retracted so as to advance the anchor ring forwardly by the same distance before being rigidly located within the lining 22 once again by expansion of the rams 21. This "walking" cycle is repeated when necessary to advance the device forwardly within the tunnel as the excavation proceeds.

In this embodiment the arms 1 suspending the base unit 2 include linear rams 23 thus to position the base unit as required relative to the centre line of the tunnel such that the tools may be placed in an optimum position thus further simulating the manual operation of a cutting too]. This manoeuverability is illustrated by dotted lines in Fig. 4. The respective ends of the arms 1 are spherically shaped so as to accommodate movement of the rams 23.

It will be appreciated that the device according to both embodiments, is lightweight and portable and serves as closely as possible to replicate manual operation of handheld cutting tools. The device may be operated automatically under computer control so as to be programmed to work in the most efficient manner for a complete cycle of cutting. The bracing arms 1 hold the base unit 2 sufficiently rigidly that a greater force may be applied to the tool than in the case of a human operator. The tools may be in the form of picks, chisels, spades and the like, as required. In the case of larger tunnels and excavations of non-standard crosssection the support ring 17 and anchor ring 20 can be replaced by support beams and/or columns.

Claims

-8CLAIMS

1. A ground cutting device comprising at least one cutting tool mounted on a frame for manipulation of the tool, the frame being mounted on a base unit; means for advancing the tool towards a ground face to be cut; and at least one bracing member supporting the base unit rigidly with respect to the ground to be cut.

2. A ground cutting device according to Claim 1, wherein the bracing member comprises a framework of arms suspending the base unit from a ground support shield or permanent ground support means.

3. A ground cutting device according to Claim 1 or Claim 2, wherein the frame is mounted on the base unit thus to be advanced with respect thereto towards the ground face to be cut.

4. A ground cutting device according to any preceding claim, wherein the frame is mounted on the base unit for rotation relative thereto thus to manoeuver the tool about the axis of rotation.

5. A ground cutting device according to any preceding claim, including a plurality of tools capable of being mounted on the frame each by way of an arm about which the tool may be articulated.

6. A ground cutting device according to any preceding claim, adapted for operation automatically by computer controlled means.

7. A ground cutting device according to any preceding claim, wherein the frame is adapted to be parked on the base unit thus to provide free access beneath same for removal of excavated ground material.

8. A ground cutting device according to any preceding claim, including ground support means movable to enable the base unit and frame to be advanced forwardly as the ground is excavated.

9. A ground cutting device according to any preceding claim, wherein the frame is movable selectively in opposite directions relative to the base unit thus to advance and retract the tool from the ground face to be cut.