IE20040305U1 - A screening bucket - Google Patents

Abstract

ABSTRACT A screening bucket (10) pivotally connectable to a movable arm of an excavator comprises a digging edge (15), a pair of digging sidewalls (20) and a screening apparatus (25) at the back wall (28) of the bucket. The screening apparatus (25) comprises a plurality of substantially parallel rotors (35) with axially spaced discs (25) mounted thereon, each of which discs (25) is provided with at least one radially projecting arm (42) operable to crush against the material delivered into the screening bucket (25). Spaces are provided between adjacent discs (40) so that the crushed material can pass through the spaces. The rotors (35) are driven with a single chain (60) which chain is suitable to encompass the rotors (35) in a manner enabling rotation of the rotors (35) in the same direction. Alternatively, the chain (60) is suitable to engage opposite sides of adjacent rotors (35) enabling rotation of the rotors (35) in alternating directions. The chain (60) is provided with a tightening device for adjusting the tension of the chain (60) on the rotors (35).

Description

A SCREENING BUCKET The present invention relates to a screening bucket, i.e. a bucket which can handle material and screen the material.

The present invention provides a screening bucket pivotally connectable to a movable arm of an excavator, the screening bucket comprising a digging means at the mouth of the bucket and a pair of digging sidewalls, the digging means being suitable to dig material such as compacted earth, soil, clay or stone directly into the bucket, the screening bucket further comprising a screening apparatus at the back wall of the bucket, said screening apparatus comprising a plurality of substantially parallel rotors, the rotors being operable to be driven by a motor, wherein axially spaced discs are mounted on a rotor, the discs being provided with at least one radially projecting arm, the arm being suitable to crush against the material delivered into the screening bucket, and wherein spaces are provided between adjacent discs so that the crushed material can pass between them and wherein the design of the screening apparatus and the spacing of the rotors, discs or arms lend to material not being thrown out of the bucket during screening.

Advantageously, the screening bucket comprises two side plates, at least one top plate and at least one bottom plate, and wherein the side edges of the top plate, the side edges of the bottom plate and respective locations of the side plates are provided with inter- engageable elements for pre-securing the top plate, the bottom plate and the side plates together thereby assisting the manufacturing process of the screening bucket at an intermediate stage thereof.

Ideally, the rotors are driven by a single chain drive mechanism, the chain of which is suitable to engage with the rotors in a manner enabling the rotors to rotate in the same direction, and alternatively wherein the chain is suitable to be engaged with the rotors in a manner enabling contra-rotation of two adjacent rotors.

Conveniently, the chain of the single chain drive is provided with at least one tightening device operable to adjust the tension of the chain when the chain is engaged with the rotors.

OPEN TO PUBUC INSPECTION UNDER SECTION 28 Am; RULE 23 Preferably, the tightening device comprises an extendable jockey extending between two opposing locations on the chain when engaged with the rotors, the jockey having first and second ends, the first and second ends having low friction heads which are engageable with the chain; and the jockey having an adjustment means operable to vary the distance between the first and second heads against two opposite locations on the chain to adjust the chain tension.

Optionally, the jockey comprises a first shaft and a second shaft, each shaft having a threaded end engageable with the head at the end and a central block connecting the two shafts.

Advantageously, the discs may be in a form of cam discs, or alternatively, in a form of fixed centre discs.

Conveniently, the radially projecting arms may be in a form of removable and adjustable teeth held in cleat elements, the cleat elements being mounted between two adjacent discs, and the removable and adjustable teeth may be fixed in the cleat elements by bolts.

Alternatively, the radially projecting arms may be formed integrally with the discs.

The discs of a pair of adjacent rotors may be positioned in a staggered manner on the pair of rotors, and the radially projecting arms may extend into spaces between two respective adjacent discs of the other rotor.

Optionally, two radially projecting arms may be provided for each disc, the arms projecting in opposite directions, one of the two arms being shorter and wider than the other of the two arms. These discs may be mounted on a rotor in a helical manner so that that equal points of the discs on the rotor form a helix, the helix having a maximum pitch equal the distance between the terminus discs of the rotor.

The invention will hereinafter be now described with reference to the accompanying drawings which show by way of example only, one embodiment of a screening bucket according to the invention.

In the drawings: Figure 1 is a perspective view of the screening bucket; Figure 2 is a cross—sectiona| side view of the screening bucket; Figure 3 is cross-sectional plan view of the screening bucket; Figure 4 is perspective view of one set of rotatable discs forming part of the screening apparatus; and Figure 5 is a side view of one set of rotatable discs of Figure 4.

Figure 6 is a perspective view of the screening bucket with digging fingers attached.

Figure 7 is an exploded view of the bucket of Figure 6 showing inter—engageab|e elements of the top plate, the bottom plate and the side plates of the bucket.

Figure 8 is a perspective view of a protective barrier of the screening apparatus.

Figure 9 is a plan schematic view of the rotors of the screening apparatus, the chain and three chain tightening means.

Figure 10 is a schematic illustration of the chain and rotors in a contra-rotational mode of operation.

Figure 11 is a perspective schematic illustration of the chain tightening means orjockey.

Figure 11a is perspective view of the jockey.

Figure 11b is a plan view showing the jockey installed between two lengths of a chain which is moving in an anti-clockwise direction.

Figure 11c is a plan view showing the jockey installed between two lengths of a chain which is moving in a clockwise direction.

IE 040305 Figure 12 is a perspective view of another set of rotatable discs with projecting arms incorporated there-between.

Figure 13 is a plan view of an alternative disc of the screening apparatus in accordance with the invention.

Figure 14 is a perspective schematic view of a set of the discs of Figure 13 assembled on a rotor.

Referring to the drawings, screening bucket 10 comprises a toughened digging edge 15 and a pair of digging sidewalls 20, a screening apparatus 25 at the back wall 28 of the bucket and a pair of flanges 30 by which the bucket can be connected to the digging arm of an excavator (not shown). Toughened digging tines or fingers 15a can be attached to the digging edge 15 and sidewalls 20 (as shown in Figure 6), if necessary.

The screening apparatus 25 comprises six parallel mounted rotatable rotors 35 driven by hydraulic motors 36. Each of the rotors 35 comprises nine fixed centre discs 40 each of which has four flails 42 (see Figure 5 and Figure 4) which are used to break up compacted clay, soil or other material delivered into the bucket. A single greasing system is provided for the apparatus 25. The discs are readily replaceable if damaged.

Although not shown in the drawings, the bucket can be modified so that the discs can be offset by means of a cam type arrangement or the rotors can be eccentrically mounted in order to enhance the flail effect of the arms, if the bucket is used for handling stone.

The rotors 35 are easily accessible and replaceable as they are externally fitted. The hydraulic motors 36 are internally mounted, do not interfere with the digging function of the bucket, are easy to service and are not exposed to the elements.

The material broken by the rotating discs and arms or flails 42 falls through a protective barrier 50 (see also Figure 8) at the back wall 28 of the bucket so as to fall onto a stockpile of screened material.

As shown in Figures 6 and 7 the screening apparatus 10 further comprises top plates 21 and 21a and bottom plates 22 and 22’. Side edges of the top plates 21 and 21a are lE040305 provided with tongues 21a and 21’a respectively. The tongues 21a and 21’a are engageable with respective slots 22a and 22’a of the side plates 20. The tongues 22a and 22’a are engageable with respective slots 20b and 20b of the side plates 20. The presence of the inter-engageabie tongues and slots is useful for pre-securing the top plates before welding thereby assisting the manufacturing process of the screening bucket.

The rotors 35 of the screening apparatus are driven by the motors 36 via a single chain 60. The chain 60 is suitable to encompass the rotors 35 in a manner enabling rotation of the rotors 35 in the same direction, as shown in Figure 9. Alternatively, the chain 60 is also suitable to engage opposite sides of adjacent rotors 35 enabling rotation of the rotors in alternating directions, as shown in Figure 10.

For a mono—directiona| mode of operation a tightening device or jockey 65, shown in Figure 11 and Figure 11a, is provided forthe chain 60. The tightening device comprises two shafts 66 and a central block 68. Each shaft 66 comprises a chain engageabie head 67 and a lock nut 69. The heads 67 are made of a low friction plastics material such as nylon and have a slot 64 to engage with the chain. The shafts 66 engage the block 68 and by adjusting the lock nut 69 clockwise the distance between the two heads 67 is extended to take up the slack on the chain.

As shown in Figure 11b, when power is applied to the rotors 35 from a driving gear 80 to a driven gear 82 in an anti-clockwise motion, the bottom length of the chain 60 tensions and moves the jockey 65 upwards. As shown in Figure 11c when power is applied from the driving gear 80 to the driven gear 82 in a clockwise motion, the upper length of the chain tensions and moves the jockey 65 downward in relation to the drawing.

Figure 12 illustrates another configuration of the discs and arms of the screening apparatus. In this embodiment cleats 43 are mounted in the spaces between circular discs 44. Radially projecting teeth 45 are held in the cleats 43 and fixed therein by means of bolts (not shown). The teeth 45 are particularly suitable for handling rock and stone.

A further alternative disc is shown in Figure 13. Each disc 46 comprises two radially projecting arms 47 and 48. The design of the discs 46 is such that the arm 47 is shorter and wider than the arm 48. Such design of the discs is particularly suitable for handling E 040305 clay. The discs 46 are preferably mounted on the rotor 35 in a helical manner so that equal points of the discs of the rotor form a helix, the helix having a maximum pitch equal the distance between the terminus discs of the rotor.

It is to be understood that the invention is not limited to the specific details described herein which are given by way of example only, and that various modifications and alterations are possible without departing from the scope of the invention as defined in the appended claims.

Claims (1)

CLAIMS:

1. A screening bucket pivotally connectable to a movable arm of an excavator, the screening bucket comprising a digging means at the mouth of the bucket and a pair of digging sidewalls, the digging means being suitable to dig material such as compacted earth, soil, clay or stone directly into the bucket, the screening bucket further comprising a screening apparatus at the back wall of the bucket, said screening apparatus comprising a plurality of substantially parallel rotors, the rotors being operable to be driven by a motor, wherein axially spaced discs are mounted on a rotor, the discs being provided with at least one radially projecting arm, the arm being suitable to crush against the material delivered into the screening bucket, and wherein spaces are provided between adjacent discs so that the crushed material can pass between them and wherein the design of the screening apparatus and the spacing of the rotors, discs or arms lend to material not being thrown out of the bucket during screening. A screening bucket as claimed in Claim 1, wherein the screening bucket comprises two side plates, at least one top plate and at least one bottom plate, and wherein the side edges of the top plate, the side edges of the bottom plate and respective locations of the side plates are provided with inter—engageab|e elements for pre-securing the top plate, the bottom plate and the side plates together thereby assisting the manufacturing process of the screening bucket at an intermediate stage thereof, and optionally wherein the inter-engageable elements are in a form of tongues provided at the side edges of the top plate and at the side edges of the bottom plate and matching slots provided at the respective locations of the side plates, and optionally wherein an external barrier is provided at the back wall of the screening bucket, and optionally wherein the rotors are driven by a single chain drive mechanism, the chain of which being suitable to engage with the rotors in a manner enabling the rotors to rotate in the same direction, and alternatively wherein the chain being suitable to be engaged with the rotors in a manner enabling contra-rotation of two adjacent rotors, and optionally wherein the discs are in a form of cam discs, and optionally wherein the discs are in a form of fixed centre discs. A screening bucket as claimed in any one of the preceding claimsifiwljjuein the chain of the single chain drive is provided with at least one tightening device dpegeble to adjust the tension of the chain when the chain is engaged with the rotors, and optionally wherein the tightening device comprises an extendable jockey extending between two opposing locations on the chain when the chain is engaged with the rotors, the jockey having first and second ends, the first and the second ends having low friction heads which are engageable with the chain, and the jockey having an adjustment means operable to vary the distance between the first and the second heads against two opposing locations on the chain to adjust the chain tension, and optionally wherein the jockey comprises a first shaft and a second shaft, each shaft having a threaded end engageable with a head at the end and a central block connecting the two shafts. A screening bucket as claimed in Claims 1 to 3, wherein the radially projecting arms are in a form of removable and adjustable teeth held in cleat elements, the cleat elements being mounted between two adjacent discs, and the removable and adjustable teeth being fixed in the cleat elements by bolts. A screening bucket as claimed in Claims 1 to 3 wherein the discs of a pair of adjacent rotors are positioned in a staggered manner on the pair of rotors, and optionally wherein the radially projecting arms extend into spaces between two respective adjacent discs of the other rotor, and optionally wherein the radially projecting arms are formed integrally with the discs, and optionally wherein two radially projecting arms are provided for each disc, the arms projecting in opposite directions, one of the two arms being shorter and wider than the other of the two arms, and optionally wherein the discs are mounted on a rotor in a helical manner so that that equal points of the discs on the rotor form a helix, the helix having a maximum pitch equal the distance between the terminus discs of the rotor. MACLACHLAN & DONALDSON Applicants‘ Agents,