EP0705371A1

EP0705371A1 - Improved bucket with screening device

Info

Publication number: EP0705371A1
Application number: EP95916900A
Authority: EP
Inventors: Rolf Ake Hellgren
Original assignee: Hellgren Gunnborg Margit Linea
Current assignee: Hellgren Gunnborg Margit Linea
Priority date: 1994-04-20
Filing date: 1995-04-18
Publication date: 1996-04-10
Also published as: SE9401348L; NO303136B1; SE9401348D0; SE501521C2; NO955169L; NO955169D0; FI956105A; FI956105A0; WO1995029297A1

Abstract

This invention shows how the effects of a bucket-mounted screening device in a loader/excavator can be made more efficient. The bucket, which is used for excavation, is equipped with a screen. In contrast to known techniques, by suspending the screen in the upper part of the bucket, a rocking motion can be imparted to the screen. The rocking movement, in contrast to a linear movement, results in the material on the screen being transported to the centre, which results in a faster through-flow of material.

Description

Improved bucket with screening device

Technical field

This invention concerns a bucket with a screening device to be fitted to equipment such a tractor loaders, excavators or front-loaders. In conjunction with soil haulage using such equipment, it is often necessary to sort materials by size into their component parts. This may concern sand and gravel fractions or bark from a barking plant, after which the various fractions can be used in gardens.

Technical viewpoint

Swedish patent applications 454711 and 454096 as published for opposition show a solution within this technical field, which consists of a bucket modified to a rotating screen. Here it is clearly shown that it is only possible to handle bulky, lightweight materials, as the rotating basket is also used as a bucket. This solution cannot be used for heavier masses, as the risk of the rotating basket being damaged is obvious.

A similar solution is shown in EP 106412. Here the disadvantage of the lightweight construction in SE 454711 has been eliminated by an apparently more robust construction. Here, however, is shown the disadvantage of a complicated and, thereby, expensive-to-manufacture device with many working parts exposed to the material being handled.

A solution that is in fact elegant but, unfortunately, with limited application is shown in EP 47041. This bucket on a front-loader has the practical limitation of sorting paving stones from sand and soil when demolishing roads or pavements surfaced with these materials.

The Swedish patent application 466839, as published for opposition, like 454711, has a drum. In this case the drum is placed at right angles to the direction of travel and screening is done in two stages, by first screening and then emptying the coarse material retained in the bucket. The Swedish patent application 464094 as published for opposition shows a solution for buckets with an inner, basket-like bucket which has been mounted to retain coarse material, which in a later, second stage can be emptied. The operation of this inner bucket requires an additional hydraulic piston.

The Swedish patent applications 462110 and 468857 as published for opposition both present a solution that most likens this invention. These involve a bucket with a screen as parts of the bottom. The bucket is used to excavate, which can be done as the front part of the bucket is designed as a normal bucket, in contrast to the above related buckets, which only permit processing of more lightweight materials. In both cases it is possible to excavate with the bucket and after taking a bucketful to carry out screening. In 462110, it is only a screen, while 468857 shows two screens for further screening. In both cases the screen is/screens are made to move by means of an eccentric motor, which is driven hydraulically.

Presentation of the invention

The object of this invention is to increase the screening capacity in comparison with that of previously known buckets incorporating integrated screens. This is achieved by the screen, placed above a hole in the lower part of the bucket, being given a rocking movement in relation to the bucket so that the hole in the bottom of the bucket is always covered by the screen. Compared with the inventions described in the technical viewpoint, it has been found, surprisingly enough, that a bucket with a screen in accordance with this invention, has a considerably greater capacity. The rocking motion results in the material always being thrown to the centre of the screen and then moving towards the edges and thereby achieving a considerably greater capacity. This is a considerable improvement on screens that only move in the plane.

Figure description

Figure 1 is a section through the basic design of the bucket. The section has been drawn with a view to simplification. A standard bucket (1) for a loader/ tractor-excavator has been modified by the following equipment. Inside is located a hydraulic motor (7) which is driven by the equipment's hydraulic unit by means of hose connections (9). From the motor's drive shaft and via an eccentric wheel coupled to a crankshaft (6), a fixture device (5) between the crankshaft (6) and pendulum screen (4) is made to move so that the screen (4) with bearing (8) in the upper part of the triangular side walls (10) perform a rocking movement. The bucket is in other respects designed as a normal bucket with the front part designed for excavation, including wear parts (3) for a long service life. The connection to the equipment's boom is mounted on the top side (2).

Preferred design form The equipment, like a tractor-excavator, has a slewable boom, with several hinged parts driven by a hydraulic system. There is often also a simple hydraulic connection that permits changes between different buckets or other equipment (brushes, pallet forks, etc.). The hydraulic connection is connected to the equipment by a connection (2) that often consists of two tubes at a standard distance from one another. The lengths of the pipes can vary but are generally about 30 to 50 cm.

The design of the bucket is such that it is also easy to excavate in harder material, such as gravel or argillaceous masses. This is achieved by the front edge of the bucket being designed as an ordinary excavator bucket. This implies that the excavating edge h reinforced by wear material (3). The screen (4) is also located so that there is a certain safety distance from the edge, so that the screen is not subjected to direct contact with material that has not been loosened. Inside the safety distance mentioned above, the underside of the bucket consists of a hole (11) through which the fine material can pass during operation of the screen. In other respects the bucket is designed so as to achieve stability, i.e. a welded construction with full, solid sides and a rear section which extend up to the same height as the sides. Certain reinforcement may be necessary round the connection (2) of the hydraulic gripping device.

Holes (8) are provided in the upper part of the bucket's (1) sides. Through these holes (8) pass a pipe which passes through the sides (10) of the screen located inside the bucket sides. The pipe is provided with suitable bushes to ensure reliable movement of the screen (4). The sides (10) of the screen on each side in the bucket are connected in the lower base area by a grille (screen) (4). It has been found that seen from the side, the end length of the screen should be of the same order of size as the perpendicular distance from the screen (4) to the bearing on the through pipe (8). Especially the distance from the bearing (8) to the screen must be in the range of 50 to 150 per cent of the edge length of the screen. In the outer edge of the screen (4) shall be fastened an attachment for the grille. The procedure is the same on the front edge and a clamped joint is placed at the sides. It is also possible to attach the screen (4) permanently by welding to the sides (10), something that is not so practical if it is desirable to change to another screen mesh width.

A rocking movement is imparted to the screen (4) by a hydraulic motor (7), with the bearings (8) as the pivot point. This motor is driven by a hydraulic motor fitted to the equipment. The connection is made by means of hydraulic hoses (9) (flow in and flow out) with quick-action couplings for the sake of simplicity. It should be possible to regulate the speed of the motor by means of a valve for the hydraulic pressure/flow, to achieve various cradle vibration frequencies. Connected to the motor is a coupling which is selected so that any overload will not deform the screen (4). It has been found that a standardized chain connection is suitable. To the connection is connected an eccentric wheel on a bearing. The eccentric wheel, in turn, is connected to a crankshaft supported in journals, which is connected to the rear edge of the screen (see the arrow indicating the direction of bucket travel when loading). It has been found that a rocking movement of about 1 to 5 cm provides the best results.

The work with the bucket is performed by the bucket being filled with material, in the normal way. The bucket is then raised to the horizontal position and the hydraulic motor (7) started by hydraulic oil being supplied through the hydraulic hoses (9). In this way the material that passes through the screen will fall through the opening (11). The coarser material will remain on the screen, which may be emptied through the bucket, after a lateral movement, at another location than the normal one, i.e. by the whole equipment's boom being moved to the emptying position.

Claims

Patent claim

1.

Bucket intended to be mounted on an item of motorized equipment and which is used to sort masses into a coarser and finer particle size fractions, for which the inside of the bucket contains a screen, which moves principally backwards and forwards in one direction to speed up screening, for which the movement is driven by a hydraulic unit mounted on the equipment and in which the motor is driven by the equipment's hydraulic unit characterized by the screen being attached, as the bottom part, in a cradle consisting in addition of triangular sides, for which the upper part of these walls have a hole through which a shaft that connects the bucket walls passes and thereby permits a rocking motion, with the shaft lead-throughs as the centre of oscillation.