GB2149751A

GB2149751A - Excavator bucket and knuckle assembly

Info

Publication number: GB2149751A
Application number: GB08428362A
Authority: GB
Inventors: Norman Brocklebank; Kenneth Albert Deighton
Original assignee: Priestman Brothers Ltd
Current assignee: Priestman Brothers Ltd
Priority date: 1983-11-10
Filing date: 1984-11-09
Publication date: 1985-06-19
Also published as: GB8330052D0; GB8428362D0; GB2149751B

Abstract

An excavator comprises a boom arm 4 which carries a knuckle assembly 5, which in turn provides a mounting point for a bucket. A head unit is provided between the bucket and knuckle assembly, the head unit incorporating a bearing 27 for rotating the bucket relative to the knuckle assembly about an axis A-A transverse to the pivot axes of the knuckle assembly and substantially perpendicular to the plane of the top plate 24 of the bucket. <IMAGE>

Description

SPECIFICATION Excavator bucket and knuckle assembly The present invention relates to an excavator bucket and the knuckle assembly by means of which the bucket is attached to the end of the arm of the excavator machine.

A conventional back-hoe type excavator has a boom, an arm pivoted at one of its ends to the free end of the boom and having, at its other end, a knuckle assembly by means of which an excavating bucket is attached to the end of the arm and is orientatable in different positions relative to the end of the arm. The top plate or member of the bucket conventionally has a pair of pivot points, one of which is used to pivot the bucket on the end of the arm and the other of which is used for attachment of one end of a first link of the knuckle assembly. The other end of the first link is attached to one end of a second link, and the other end of the second link is attached to a pivot point adjacent the end of the arm.

Such a knuckle assembly is hereinafter referred to as "of the kind hereinbefore described". A hydraulic ram is usually attached to the pivot between the first and second links in order to rotate the bucket about the end of the arm. The axes of the various pivot points are all intended to be parallel with one another and are also parallel with the pivot point of the arm on the boom and the pivot point of the boom on the body or base of the excavator, so that the line of action of the bucket is constrained to lie in the plane containing the centrelines of the arm and the boom.

Particularly with wide shallow buckets, such as may be used for maintaining the batters or banks of a drainage ditch for example, it is advantageous if the bucket is able to tilt relative to the end of the arm about an axis transverse to that about which it pivots on the end of the arm under the action of the knuckle assembly. To achieve this it is known to attach one or more hydraulic rams between the knuckle assembly and the top plate of the bucket and to provide a head member between the knuckle assembly and the top plate of the bucket, the head member being pivoted to the first knuckle link and to the end of the arm, and having a pivot lying substantially in the plane containing the arm and boom to which the bucket is attached, the bucket thus tilting under the action of the hydraulic rams at the end of the arm.

This gives such a bucket the added advantage that angled profiles on banks can be cut and give the machine greater versitility.

However, it would be particularly useful if a conventional hydraulic excavator or excavator of the type described in EP-A-0077684 could be fitted with a bucket which would enable drainage ditches to be cut or maintained with the excavator lying offset to the side of the ditch, but whilst enabling the bucket to be moved along the line of the ditch rather than removing spoil substantially transversely to the line of the ditch. This would give the operator of such an excavator the ability to cut a greater length of drainage channel without having to move the position of the machine along the bank. The excavation would thus be concentrated on the deepening of the ditch without materially increasing its width. An excavator with a bucket tilting mechanism as described above is not capable of fulfilling this function.

Therefore, in order to overcome this problem, and in accordance with the present invention, an excavator comprising a boom, an arm, a knuckle assembly of the type hereinbefore described and a bucket, further includes a head unit between the bucket and knuckle assembly, the head unit incorporating means for rotating the bucket relative to the knuckle assembly about an axis transverse to the pivot axes of the knuckle assembly and substantially perpendicular to the plane of the top plate of the bucket, and lying in the plane of movement of the knuckle assembly.

Such an excavator provides for rotation of the bucket in such a way that, when the knuckle assembly is in a generally central position intermediate the end positions of its movement, the bucket is able to be rotated about an upright axis, as opposed to the substantially horizontal axis about which the tilting mechanism previously described pivots the bucket.

The invention includes a knuckle assembly of the kind hereinbefore described including a head unit of the type above described, so that existing excavators can be retro-fitted for greater versatility. In such cases, the head unit has a pair of pivot points which take the place of the conventional pivot points on the top plate of a normal bucket, and which attach respectively to the end of the arm and the one end of the first link of the knuckle assembly, pivot means, and means for attaching the bucket on the pivot means for rotation relative to the knuckle assembly.

It will be appreciated that the advantages of the invention may alternatively be provided by utilizing a conventional knuckle assembly, but modifying the top plate or member of the bucket so as to provide a head unit which is integrally formed with the top plate of the bucket and which incorporates the necessary pivot.

Preferably, the pivot is provided by means of a conventional annular bearing which may comprise a tapered roller bearing. Permanent stops or other means can be provided to limit the rotation within the maximum required angle.

For certain applications it may be desired that the rotation of the bucket about the pivot on the head unit be limited or restricted, and this may be achieved by friction brake pads, by the use of hydraulics with an appropriate hydraulic lock, by hydraulic motor controlled rotation, or simply by means of indexable locking pins.

One example of a machine constructed in accordance with the present invention will now be described with reference to the accompanying representations in which: Figures 1A and 18 illustrate diagrammatically a first machine of the type described in EP-A-0077684, in side elevation and plan respectively; Figures 2 and 3 illustrate the same machine in plan with an alternative bucket; and, Figures 3A, 3B and 3C illustrate the bucket shown in Figure 2 in greater detail.

The mobile excavator 1 shown in Figure 1A and 1 B has a boom 2 mounted on a slewable body 3, and an arm 4 pivotally mounted at the end of the boom and on the free end of which is a knuckle assembly 5 which carries a head unit 6 to which is attached a bucket 7. The excavator is shown cutting at an angle across a sloping face 8 of a wide watercourse 9 for example. It can be seen from Figure 1 B that the bucket has been rotated through an angle H from a position in which it lies substantially perpendicular to the arm, whereby it can follow the plane of the slope 5.

Figure 2 illustrates the same excavator with the arm 4 in two different positions and with a modified bucket 17 which has a trapezoidal shape. The bucket 17 has a section corresponding to the cross-section of the drainage ditch 18 which is being excavated and again it can be seen that the bucket is orientated so that its plane of symmetry lies at an angle to the plane of movement of the knuckle assembly 5 and the arm 4. In this way, the excavator can work, utilizing the full length of its arm and boom by drawing the bucket along the channel at a changing angle to its usual working plane enabling the bucket to follow the line of the drainage ditch 18.

Figures 3A, 3B, 3C illustrate the knuckle assembly 5 and the bucket 17 shown in Figure 2 in more detail.

The knuckle assembly 5 has a first link 19 (connected to a head unit 26) and a pair of second links 20 (connected by pivot 20' to the arm 4), the pivot pin 19' connecting the links 19,20 also connecting a ram 21 of a hydraulic cylinder 22 which is pivotally mounted on the arm 4 and extendable retractable to move the knuckle assembly and hence the bucket in the direction of arrows B.

The bucket 17 has a trapezoidal shape as best shown in Figure 3B, comprising side members 23, a cross-plate 24, and a base wall 25. To the cross-plate 24, otherwise referred to as a top plate, a head unit 26 is attached having an anti-friction bearing 27 which enables the top plate 24 and hence the bucket to rotate about axis A-A relative to the knuckle assembly 5, as shown by arrows C Pivot pins 28 and 29 enable the head unit 26 to be attached to the link 19 of the knuckle assembly 5 and the end of the arm 4 of the excavator respectively and to be moved under the control of the cylinder and ram (21,22).

Claims

1. An excavator comprising a boom, an arm, a knuckle assembly of the type hereinbefore described and a bucket, further comprising a head unit between the bucket and knuckle assembly, the head unit incorporating means for rotating the bucket relative to the knuckle assembly about an axis transverse to the pivot axes of the knuckle assembly and substantially perpendicular to the plane of the top plate of the bucket, and lying in the plane of movement of the knuckle assembly.

2. An excavator according to claim 1, wherein the head unit has a pair of pivot points which take the place of the conventional pivot points on the top plate of a normal bucket, and which attach respectively to the end of the arm and the one end of the first link of the knuckle assembly, pivot means, and means for attaching the bucket on the pivot means for rotation relative to the knuckle assembly.

3. An excavator according to claim 1 or claim 2, wherein the means for rotating the bucket relative to the knuckle assembly comprises an annular bearing.

4. An excavator according to claim 3, wherein the bearing is a tapered roller bearing.

5. An excavator according to any of claims 1 to 4, wherein stops or other means are provided to limit the rotation.

6. A knuckle assembly of the kind described, for mounting on an arm of an excavator, the assembly including a head unit between the bucket and knuckle assembly, the head unit incorporating means for rotating the bucket relative to the knuckle assembly about an axis transverse to the pivot axes of the knuckle assembly and substantially perpendiocular to the plane of the top plate of the bucket, and lying in the plane of movement of the knuckle assembly.

7. A knuckle assembly according to claim 6, wherein the head unit has a pair of pivot points which take the place of the conventional pivot points on the top plate of a normal bucket, and which attach respectively to the end of the arm and the one end of the first link of the knuckle assembly, pivot means, and means for attaching the bucket on the pivot means for rotation relative to the knuckle assembly.

8. A knuckle assembly according to claim 6 or claim 7, wherein the means for rotating the bucket relative to the knuckle assembly comprises an annular bearing.

9. A knuckle assembly according to claim 8, wherein the bearing is a tapered roller bearing.

10. A knuckle assembly according to any of claims 6 to 9, wherein stops or other means are provided to limit the rotation.

11. An excavator substantially as described with reference to the accompanying drawings.

12. A knuckle assembly for an excavator, substantially as described with reference to either of the examples shown in the accompanying drawings.