NZ211947A - Grapple arm attachment for bucket excavator co-operates with bucket to exert pincer action - Google Patents

Description

"iwrftinin iwvimwmwi iiw PATENTS FORM NO; 5 Fee No. 4: Jllb.OO After Provisional No: 211947 Dated: 1st May 1905 THE PATENTS ACT 195J COMPLETE SPECIFICATION TITLE: "EXCAVATOR FITTING" 211947 N.Z. PATENT OFFICII } 3 C ArH;:36 RECEiVHO NOEL GEORGE CLARK, a British subject and New Zealand citizen of 18 Orchard East Road, Ngatea, New Zealand hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed to be particularly described in and by the following statement: 211947 This invention concerns attachments for excavators.

Whereas the invention is applicable to face shovels it is primarily intended for backhoes and mini-hoes. Backhoes which are used for trenching and which have a bucket action which mimicks the movement of the human wrist are commonly used by contractors at rubbish tips and demolition sites for handling debris. One such machine is available under the trade mark GRADAWL. Although such machines can be very effective in the hands of skilled operator, chunks of masonry which are too large to remain in the bucket, beams of timber, tree stumps, pipes and wire reinforcement all present difficulty to the machine operator. It is common to bring in a front end loader with a split bucket or clamshell bucket to do part of the clearing work which the excavator cannot handle. This invention addresses that problem.

This invention provides an attachment for a bucket excavator of the backhoe or face shovel type comprising (a.) a grapple arm which is capable of pivotal attachment to the excavator boom or the excavator dipper arm (bj a ram connectable to the hydraulics of the excavator and pivotally connected to the grapple arm so as to co-operate with a bucket in exerting a pincer action The most convenient geometry is achieved by connecting the grapple arm to the dipper arm close to the bucket. Preferably the grapple arm is tiltabie between a closed position in which the arm lies across at least part of the face of the bucket and an open position in which the arm lies retracted and clear of the bucket face. For most applications an arc of movement of between 20° and 90° will suffice.

The grapple arm may be of fixed length but I find it more convenient to construct it to be extendable to at least the lower edge of the bucket. For this purpose the grapple arm may be of box section consisting of a hollow stem and a telescopic part with means to fix the telescopic part at the desired length of extension. The grip which the grapple arm provides can be improved by a provision of a lip, teeth or similar projections directed toward the teeth or lower working edge of the bucket. 211947 If the grapple arm is mounted so as to bisect the bucket, the pincer action may be likened to that of the hand where the upright edges of the bucket correspond to a pair of fingers and the grapple arm corresponds to a thumb. For some applications a pair of grapple arms may be more useful. Thus a pair of grapple arms are connectable to the dipper arm at the axis of bucket rotation, both grapple arms being moved by the same ram. It is possible also to connect the single grapple arm at the same axis but this requires extra fitting compared to the bolting and welding of the attachment lug of the grapple arm to the dipper arm. It is feasible to have the grapple arm constructed as a bell crank but there is no strict need for increased mechanical advantage such as the lever would provide unless heavy material is to be picked up when the stiffness of the dipper arm and boom come into consideration.

Embodiments of the invention is now described by way of example with reference to the accompanying drawings in which: Figure 1: is a side view of an excavator dipper arm with a grapple arm in the closed position, Figure 2: is a front elevation of the arm detached from the excavator showing its extensibility, and Figure 3: is a perspective view of the bucket full of spoil with the grapple fully retracted to permit the bucket to dig.

Figure 4: is a front elevation of the arm modified as a scoop.

Referring firstly to Figure 1, the lower limb 2 of the articulated jib of a trench digging excavator has a bucket 4 which rotates with a wrist action under the influence of ram 6. The rear face of limb 2 has a pivot 8 which mounts grapple arm 10. The upper body 12 of the grapple arm is of box-section, the lower body 14 of the arm being telescopic with the upper body. The length of extension of the lower body is adjustable by the provision of sets of bores 16 in both upper and lower bodies and a 211947 pin 18. The upper body has a pair of splayed wings 20 which fit on each side of pivot 6. A 8tout pin 22 connects the arm to the limb 2. Close to wings 22 is a pair of lugs 24 which act as the lower mount for the pincer ram 26. The lower end of the body 14 has a foot 28 with teeth 30 which face the bucket teeth 32.

By advancing the grapple ram 26 and the bucket rams 6, a pincer action is obtainable for picking up large diameter tree stumps or smaller diameter pipes. By retracting the grapple ram 26, the grapple arm can be drawn upwardly to subtend an acute angle with a limb 2 leaving the bucket free to undergo full rotation for trench digging, scooping spoil or nudging obstructions. This latter position is shown in Figure 3.

In another embodiment shown in figure 4 the lower body part 14 has a detachable plate scoop 28 which is longer thart the width of the bucket with which it co-operates to scoop gravel or other particulate material. In a non-illustrated embodiment the scoop is replaced by a rake.

Claims (7)

211947 WHAT I CLAIM IS;

1. An attachment for a bucket excavator of the backhoe or face shovel type comprising (a) a grapple arm which is capable of pivotal attachment to the excavator boom or the excavator dipper arm and (b) a ram connectable to the hydraulics of the excavator and pivotally connected to the grapple arm so the grapple arm co-operates with the bucket to exert a pincer action.

2. An attachment as claimed in claim 1 wherein one end of the grapple arm is connectable to the dipper arm close to the bucket.

3. An attachment as claimed in claim 2 wherein the grapple arm is tiltable between a closed position in which the arm lies across at least part of the face of the bucket and an open position in which the arm lies retracted and clear of the bucket face.

4. An attachment as claimed in claim 2 or 3 wherein the grapple arm is extendable to at least the lower edge of the bucket.

5. An attachment as claimed in any one of claims 1 to 4 wherein the grapple arm consists of a hollow section and telescopic section with means to fix the telescopic section at the desired length of extension.

6. An attachment as claimed in any one of claims 1 to 5 wherein the free end of the grapple arm has a lip, teeth or like projection to improve grip.

7. An attachment as claimed in any one of the preceding claims wherein the grapple arm is of box section. -5- N.Z. PATENT Of F1CE -5 MAR I9S7 211947 An attachment as claimed in any one of the preceding claims wherein the grapple arm has a forwardly extending Jug to which one end of the ram is connected in order to increase the working arc of the arm. An attachment as claimed in any one of claims 1 to 5, 7 or 8 wherein the arm has a plate which acts as a scoop for filling a bucket with particulate material. An attachment as claimed in any one of claims 1 to 8 wherein a pair of grapple arms are connectable to the dipper arm at the axis of bucket rotation, both grapple arms being moved by the same ram. An attachment for an excavator substantially as herein described with reference to and as illustrated in figures 1 to 3 or as modified in figure 4. An excavator equipped with an attachment as claimed in any one of the preceding claims. NOEL GEORGE CLARK by his Attorneys BARRY V. JAMES & ASSOCIATES