Attachment for excavator

The present invention relates to an attachment for an excavator.

Many excavator arrangements are known which use both a bucket and a cutter, such as those described in JP2000336689, JP2000273896, JP9088354 and JP1207507.

The attachment of the present invention provides an alternative and in some respects an improved cutter to those of the prior art.

In accordance with a first aspect of the present invention, there is provided an excavator attachment for an excavator, the attachment comprising (i) a bucket portion for receiving excavated material or a scoop portion for collecting excavated material, and (ii) a cutter device capable of cutting and excavating rock, wherein the cutter device comprises a rotary cutter of elongate configuration having a proximal end associated with the bucket portion or scoop portion, and a distal end remote from the bucket portion or scoop portion and is so arranged that, in use, the orientation of the elongate rotary cutter relative to the bucket portion or scoop portion is fixed.

The terms “cutter” and “cutting” include within their meaning boring, scraping and other means of removing rock or the like from a substrate.

The term “rock” is taken to include non-mineral substrates of a relatively hard nature, such as coal, and relatively hard man-made substrates, such as tarmac and concrete.

In use, the orientation of the elongate rotary cutter relative to the bucket portion or scoop portion is fixed. Certain parts of the elongate rotary cutter may move (such as any cutting teeth or the like). The rotary cutter may be removed, for example, from the rest of the attachment in order to replace, service, repair or renovate the rotary cutter. The orientation of the elongate rotary cutter relative to the bucket portion or scoop portion may not be changed in use, for example, as shown in JP2000336689. The attachment itself may, of course, be moved during use.

It will therefore be appreciated that, in use, the position (and not merely the orientation) of the elongate rotary cutter relative to the bucket portion or scoop portion is preferably fixed.

The attachment may comprise a connecting portion for pivotal connection to an excavator. The connecting portion may be located between the bucket or scoop portion and the elongate rotary cutter. The connecting portion may be provided with an aperture for receipt of a pin.

Where a scoop portion is used, the scoop portion may be formed with a rear wall and two side walls, the two side walls projecting from the rear wall. This forms a scoop that is capable of moving excavated material, but not capable of picking it up. The side walls assist in the gathering of excavated material.

Where a scoop portion is used, the scoop portion may act like a shovel for moving excavated material along the ground.

It is preferred that the elongate rotary cutter comprises a multiplicity of cutting elements. It is further preferred that the cutter elements are rotatable about the longitudinal axis of the elongate rotary cutter. The elongate rotary cutter may comprise one or more outer members which is rotatable with respect to an inner member. The elongate rotary cutter may comprise a plurality of outer members. Each cutter element may be associated with one of the one or more outer members. The outer members may have an annular shape. Alternatively, the cutter elements may be associated with a rotatable, substantially rigid cylindrical cutter body. The cutter elements may be attached to, or integral with, the cutter body. It is preferred that cutter elements project substantially laterally or radially. The cutter elements are typically in the form of picks suitable for rock cutting. Such picks may have a steel body with a tungsten carbide or other ceramic cutting tip. Such picks may have a steel cutting tip if being used to cut coal, for example.

It is preferred that the attachment is a substantially linear arrangement.

The cutter device may be provided with a motor or the like for driving elongate rotary cutter. The motor may be hydraulic.

The attachment may comprise a body providing the bucket (or scoop) portion and a receiving portion for the receipt of the cutter device, wherein the cutter device is received by the receiving portion of the body.

The body may be integrally formed i.e. it may be provided in substantially one piece. The body is preferably formed, however, by welding together several pre-cast pieces.

The receiving portion is preferably arranged so that the distal end is remote from the bucket portion or scoop portion. The receiving portion may be in the form of an aperture or recess in the body.

If the attachment is provided with a connecting portion for pivotal connection to an arm of an excavator, the connection between the excavator and the connecting portion, in use, providing a first axis of rotation of the elongate rotary cutter and the bucket portion (or scoop portion), the attachment may be provided with one or more components that, in use, facilitates rotation of the elongate rotary cutter and the bucket portion (or scoop portion) about a second rotational axis, the second rotational axis being angled with respect to the first axis of rotation. “Angled” means that the said axes are not parallel to one another. It is preferred that the angle between the first axis of rotation and the second rotational axis is from 45 to 135 degrees (more preferably from 60 to 120 degrees and further more preferably from 80 to 110 degrees).

It is further preferred that the angle between the second rotational axis and the longitudinal axis of the elongate rotary cutter is from 45 to 135 degrees (more preferably from 60 to 120 degrees and further more preferably from 80 to 100 degrees).

It has been found that the presence of such an axis of rotation enables the top (as opposed to the side) of the elongate rotary cutter to be presented to a substrate. This provides better performance; it was found that if the side of a cutter was presented to the substrate to be cut then the cutter and associated excavator tended to bounce. Furthermore, the size of the pieces of rock and coal removed from the substrate was lower than desired. Such an arrangement allows the cutter to be moved into many operating (i.e. cutting) positions by rotation about the second rotational axis.

It is preferred that said one or more components facilitates rotation of the elongate rotary cutter and the bucket portion (or scoop portion) through at least 300 degrees (preferably through at least 340 degrees and more preferably through at least 360 degrees) about said second rotational axis.

The one or more components may comprise a motor for rotating the elongate rotary cutter and the bucket or scoop portion about said second rotational axis. The attachment may not be provided with a motor for rotating the elongate rotary cutter and the bucket or scoop portion about said second rotational axis, instead being provided with a bearing (such as a roller bearing) and/or an attachment means for attachment to a motor facilitating the rotation of the elongate rotary cutter and the bucket or scoop portion about said second rotational axis.

It is preferred that said one or more components facilitates the fixing of the rotational position of the elongate rotary cutter and the bucket or scoop portion about said second rotational axis.