GB2064473A - Bucket mechanism for material removal - Google Patents

Abstract

An excavator bucket mechanism comprising a bucket 1 mounted on a support arm 3 and pivotable through 180 DEG by a ram 5. An ejector 4 is pivotably mounted on the arm 3 and disposed within the bucket 1. During a digging operation, the ejector 4 is pushed by the entry of material from the position shown in dotted lines to the position shown in full lines. During ejection of the material, the bucket is pivoted clockwise whilst the ejector 4 is held in position by a latch 12 thereby ejecting the material. <IMAGE>

Description

SPECIFICATION Bucket mechanism for material removal This invention relates to a bucket mechanism for use on earth moving equipment such as excavators and including an ejector element within the bucket for the removal of spoil therefrom after a digging operation.

It is desirable that the bucket in a bucket mechanism for earth moving equipment should be capable of pivoting through about 1800, usually from a position in which the mouth of the bucket is adjacent to the arm which carries the bucket.

With this degree of pivotal movement, the actuation of an ejector element within the bucket gives rise to problems and conventional bucket mechanisms which are capable of such an angular movement are often either not provided with an ejector element or require an expensive ram mechanism to operate the ejector element.

An object of the present invention is to provide a bucket mechanism which includes an ejector element and also retains the facility of approximately 1800 of angular movement, whilst being of relatively simple and robust construction.

According to the present invention, a bucket mechanism includes a bucket adapted for pivotal mounting on a support arm and for connection to actuating means operable to effect pivotal movement of the bucket through an arc of approximately 1 800, an ejector element disposed within the bucket and capable of performing pivotal movement independently of the bucket while the bucket performs a part of its pivotal arc in one direction, and stop means operable to prevent pivotal movement of the ejector element while the bucket performs another part of said pivotal arc, whereby, during the latter part of the arc, relative traverse occurs between the ejector element and the bucket over at least a part of the bucket volume to eject the contents thereof.

In one convenient arrangement, said stop means is mounted, preferably pivotally, for movement between operative and inoperative positions, and may conveniently be spring-urged towards at least its operative position.

When the stop means is pivotally mounted, it may conveniently be influenced by a spring which is over-centre in relation to the pivot of the stop means and urges the latter alternately into one or the other of said positions.

The actuating means for the bucket, normally a ram, is preferably connected to the bucket via a radius arm pivoted on the support arm, possibly with the interposition of a slave link between the radius arm and bucket.

The invention will now be described, by way of example, with reference to the accompanying drawings which are diagrammatic representations of one form of the bucket mechanism of the invention, showing the bucket respectively in three different stages of operation.

The bucket mechanism illustrated in the drawings includes a bucket 1 pivotally mounted by means of a shaft 2 on a support arm 3 which may conveniently be the boom of an excavator or similar earth-moving device. An ejector element 4 is also pivotally mounted on the support arm 3, in this case on the shaft 2, although a separate mounting means for the ejector element may be employed, if desired. The bucket 1 is pivotable through approximately 1 800 in an anticlockwise direction from the position shown in Figure 1 by -means of a ram 5, a piston rod 6 of which is connected to a radius arm 7 pivoted at 8 on the support arm 3. The radius arm is in turn connected to the bucket, in this case by a slave link 9, the two ends of which are pivoted respectively to the slave link 9 and a bracket 10 rigid with the bucket.

The ejector element 4 is freely pivotable independently of the bucket 1 from a position, shown in dotted lines in Figure 2, adjacent to the mouth 11 to the position shown in full lines in Figure 2, in which latter position its movement is arrested for the purpose to be described. The arresting of the ejector element is performed by a latch 12 pivotally mounted at 13 on lugs 14 rigidly secured to the arm 3. A spring represented at 15 is disposed in an over-centre relationship to the pivot 1 3 of the latch 12, the spring, in the position shown in Figures 1 and 2, acting to urge the latch into a latching position.

A digging operation would be commenced with the bucket 1 approximately in the position shown in Figure 2 in which the edge 1 6 defining the lowermost extremity of the mouth 11 is conveniently disposed for digging into the earth for example. With the bucket in this position or thereabouts, the ejector element 4 will be within its free pivoting range and will have fallen under its own weight to the position shown in dotted lines adajacent the mouth of the bucket, the ejector being prevented from falling completely out of the bucket by lugs 1 7 thereon engaging on a fixed part of the mechanism. The digging operation is commenced by operating the arm 3 and ram 5 in conventional manner to cause the bucket to scoop a quantity of earth or other material.Since the ejector element 4 is freely pivotable, entry of the material into the bucket will push the ejector element back into the bucket until, when the bucket is full of material, the ejector will have been displaced relative to the bucket to the position shown in full lines in Figure 2. During the scooping operation, the bucket will have pivoted towards or into the position shown in Figure 1 in which its mouth 11 is closely adjacent to the support arm 3.

The support arm 3 may then be operated to lift the bucket from the location at which it was filled to a further location where the contents are to be deposited, as for example on the ground or into a transporting vehicle. With the bucket in the desired position for depositing the material, the ram 5 is actuated to pivot the bucket in an anticlockwise direction from the position shown in Figure 1 through approximately 1800 to the position shown in Figure 3. During the portion of bucket movement which takes it to the position shown in Figure 2, the material within the bucket holds the ejector element in the position shown in full lines in Figures 1 and 2. However, as will be seen from Figure 2, when the bucket reaches that position, lugs 18 on the ejector element 4 come into abutment with the latch 12 and prevent further movement of the ejector element in an anticlockwise direction.Once this has happened, further anticlockwise pivotal movement of the bucket to its position shown in Figure 3 will occur relative to the now fixed ejector elements 4, thereby causing the ejector to expel the contents of the bucket. As will be seen from Figure 3, the ejector element has traversed substantially the entire volume of the bucket 1.

It sometimes happens that a digging or material lifting operation has to be commenced with the bucket shown in the position illustrated in Figure 3. It is therefore necessary to release the catch 12 to free the ejector element 4 in order to permit the latter to be pushed back by material entering the bucket during its movement from the position shown in Figure 3. In order to achieve this, the arrangement is such that a portion of the bucket contacts an extension 1 2A of the latch 12 as the bucket approaches its position shown in Figure 3 so that during the last few degrees of movement of the bucket towards the Figure 3 position, the bucket is able to pivot the latch 12 in an anticlockwise direction until the spring 1 5 moves across the centre of the latch pivot 13, at which point the latch is snapped back to its inoperative position as shown in Figure 3.The ejector element is then free-floating once again, enabling the bucket to perform a digging or filling operation from the Figure 3 position, if required. Once the bucket has moved as far as the position shown in Figure 2, the latch can safely be returned to its operative position to await subsequent contact by the ejector element 4. Return of the latch to its operative position is initiated by the radius arm 7 striking an abutment block 12B on the latch 12 as the bucket moves away from the Figure 2 position in a clockwise direction. Once the latch has been pivoted by an amount sufficient to bring the spring 1 5 across the centre of the latch pivot 13, the latch will snap back to its operative position as shown in Figure 2.It will be understood that Figure 2 illustrates the positions of components during movement of the bucket in the anticlockwise direction, since, as will be appreciated from the foregoing, the latch will not be in its operative position when the bucket passes through the Figure 2 position in the clockwise direction.

It will be understood that the latch and its associated components may take various alternative forms to those illustrated and, whilst it may be preferable to employ an over-centre spring in association with the latch in the manner described above, it would be possible to achieve the same results using alternative arrangements of springs and abutments. The invention, especially in its presently preferred form as illustrated, provides a simple and effective bucket mechanism without having recourse to a complicated ram arrangement for operating the ejector. The mechanism of the invention will be seen to permit movement of the bucket through 180 , or thereabouts.

Claims (11)

1. A bucket mechanism comprising a bucket adapted for pivotal mounting on a support arm and for connection to actuating means operable to effect pivotal movement of the bucket through an arc of approximately 180 , an ejector element disposed within the bucket and capable of performing pivotal movement independently of the bucket while the bucket performs a part of its pivotal arc in one direction, and stop means operable to prevent pivotal movement of the ejector element while the bucket performs another part of said pivotal arc, whereby, during the latter part of the arc, relative traverse occurs between the ejector element and the bucket over at least a part of the bucket volume to eject the contents thereof.

2. A bucket mechanism according to Claim 1 wherein the stop means is mounted for movement between operative and inoperative positions and in its operative position acts as an abutment to prevent said pivotal movement of the ejector element during said another part of the bucket pivotal arc.

3. A bucket mechanism according to Claim 2 wherein the stop means is mounted for pivotal movement.

4. A bucket mechanism according to Claim 2 or Claim 3 wherein the stop means is spring-urged towards at least its operative position.

5. A bucket mechanism according to Claim 1 wherein the stop means is pivotally mounted for movement between operative and inoperative positions and is influenced by a spring which is over-centre in relation to the pivot of the stop means and urges the latter alternately into one or other of said positions.

6. A bucket mechanism according to any one of the preceding claims wherein the bucketactuating means is a fluid pressure-operated ram.

7. A bucket mechanism according to Claim 6 wherein the ram is connected to the bucket via a radius arm pivoted on the support arm.

8. A bucket mechanism according to Claim 7 wherein a slave link is interposed between the radius arm and bucket.

9. A bucket mechanism according to Claim 5 wherein the stop means is arranged so as to be urged out of its operative position by the bucket as the latter approaches its uppermost position.

10. A bucket mechanism according to Claim 5 or Claim 9 wherein the stop means is arranged so as to be urged out of its inoperative position by a radius arm connecting the actuating means to the bucket.

11. A bucket mechanism substantially as hereinbefore described with reference to the accompanying drawings.