EP1495192B1

EP1495192B1 - Excavator bucket

Info

Publication number: EP1495192B1
Application number: EP03708788A
Authority: EP
Inventors: Ulf Hedberg
Original assignee: Parsgruppen AB
Current assignee: Parsgruppen AB
Priority date: 2002-03-18
Filing date: 2003-03-13
Publication date: 2010-09-08
Anticipated expiration: 2023-03-13
Also published as: ATE480673T1; SE525518C2; DE60334088D1; NO20043966L; AU2003212759A1; SE0200830D0; SE0200830L; CA2479001A1; EP1495192A1; WO2003078745A1

Abstract

An excavator bucket (A) with an upper edge having a transversally disposed connector (13) for connection to the free end of an excavator (carrier) arm system. This connection is subject to wear and compromises the service life of the b bucket (A). The present invention increases service life by having the connector (13) ends project beyond the sides of the bucket (A), each of said ends having external fixing elements (1 and 1a) that associate the connector end to the adjacent sidewall (11).

Description

The present invention is based on a design feature for an excavator bucket or earth mover bucket (these and all other such buckets being hereinafter referred to as bucket), i.e. a piece of equipment that, mounted on an excavator, earth mover or similar (hereinafter referred to as carrier), is used for excavating and/or moving a range of materials, e.g. soil, clay, gravel, stones, etc. (hereinafter referred to as excavated material).
Carriers with the type of bucket here envisaged can be found in sizes of from less than one ton up to several hundred tons (machine weight).
Consequently, depending on the carriers to which they are attached, the purposes for which they are being used and which materials are being excavated, buckets are available in a range of formats and sizes.
Common to all these different buckets is a welded steel and steel plate box structure that, to provide the opening for loading and unloading the material being dug out or moved, has one wall "missing". This box structure has to be strong enough to fulfil its purpose without mechanical failure. It must be resilient, i.e. in each work cycle it must be able to accept deformation and then return to its original shape without cracking or breaking. This applies especially to the bucket opening's two upper corners formed where the bucket attaches to its carrier (i.e. the roof) and the bucket's vertical sides. At the same time, because unnecessary weight leads to a reciprocal reduction in carrier capacity, the bucket should be as light as possible.
A further criterion common to all these buckets is that they should offer the greatest possible resistance to the wear occasioned by use. To achieve the desired strength, wear resistance and low weight, various high-strength and wear-resistant steels are used, their individual properties being matched to the intended use. Detachable or welded-in components of cast steel, or welded-in components of other materials, may be used where the structure is subjected to the greatest wear.
Buckets should also be easy to fill and empty. Furthermore, to avoid the reduction of the bucket's effective volume, and the undesirable mixing of different types of excavated materials, no excavated material should remain in the bucket after emptying. This is achieved by giving the structure as smooth an interior as possible. Edges or pockets that could prevent material leaving the bucket must be avoided whenever possible.
Thus, taking all these factors into consideration, bucket design is critical not only for bucket function but also for carrier efficiency. The solution to the problems is provided by a bucket as defined in the independent claim. Preferred embodiments are set out in the dependent claims.
The present invention is described in greater detail in the explanation of the following two drawings, viz.:

Figure 1 - a typical, present-day bucket,
Figure 2 - the same bucket with stiffeners as per the present invention.

Figure 1 shows a typical, present-day bucket with internal stiffeners. To achieve the necessary strength and stiffness, the part where the bucket attaches to the carrier, the roof (2), incorporates a beam-like element. A prefabricated steel tube is used as the beam element. This tubular beam (5) is welded to the roof (2), the sides of the structure (3) and the side cutters (4). The latter are, in their turn, welded to the bucket bottom (6) and the cutter (7). However, this design has a weakness in the corners (8) between the beam and the sides. The weakness is that the welds between the inelastic beam element, the tubular beam (5), and the relatively thin side cutters (4) tend to crack if there is internal movement in the design. To counteract this, thicker plates can be used for the sides or side cutters or, as per figure 1, stiffeners (9) can be welded internally in the bucket corners (8) between the beam element (5) and the side cutters (4). These measures overcome the cracking problem. However, thicker side cutters increase bucket weight and reduce penetration in the material being excavated. Similarly, on the inside of the bucket, internal stiffeners (9) present prominent edges and pockets to the excavated material. This inhibits loading and creates even more severe problems when unloading. The latter are particularly marked with moist excavated material, but even blasted rock can adhere to, or get jammed in, the bucket.
Figure 2 shows a bucket of the same type as in figure 1, but constructed with external beam stiffeners as per the present invention. To achieve the necessary strength and stiffness, the part where the bucket attaches to the carrier, the roof (10), incorporates a beam-like element. A prefabricated steel tube is used as the beam element. This tubular beam (13) is welded to the roof (10), the sides of the structure (11) and the side cutters (12). The latter are, in their turn, welded to the bucket bottom (14) and the cutter (15). The beam stiffeners (1), which are located on the outside of the bucket, are welded to the side cutters (12) and the tubular beam (13). The tubular beam passes through, and is encircled by, the beam stiffeners (1). To avoid dangerous loading of welds and material, the tongue-shaped part (1 a) of each beam stiffener (1) is welded fast and points downwards to the bucket bottom.
The invention ensures a controlled transmission of stresses and movement between the beam and the bucket sides. This is achieved by the tongues of the beam stiffeners allowing resilience in the structure and progressively taking up the lateral movements hinted at above. This reduces the stresses on the welds in the bucket corners (16) to a safe level.
The external beam stiffener solution gives a bucket interior completely free of any projections. Excavated material is thus given minimum opportunity to lodge in the bucket at loading and unloading.
The external placement of the beam stiffeners eliminates, as far as is possible, harmful wear and/or deformation of said stiffeners.
The invention enables improved use of modern, high-strength steels. By avoiding over-dimensioning, the weight and penetration (when excavating) of any given bucket can be, respectively, decreased and improved without negatively affecting strength.
Energy consumption and, consequentially, negative environmental impact are thus reduced as a result of the advantages assured by the invention.

Claims

A bucket (A) with a bottom (14), sidewalls (11), a roof (10) and a connector (13), the free edges of the sidewalls (11) and the free edge of the bottom (14) making up the "attack edges" of the bucket (A), these edges being the first to strike the material to be excavated when the connector (13) is set up transversely as a part of the bucket roof (10), said bucket being characterised by the connector (13) being set up at the free end of the roof (10); the connector (13) being in the form of a beam protruding beyond the sidewalls (11) of the bucket (A); and, there being fixing elements (1, 1a) associated with each protruding end and the outside of the adjacent sidewall (11).
Bucket (A) as per patent claim 1,
characterised by the connector (13) being tubular with, ideally, a circular cross section.
Bucket (A) as per patent claim 1 or 2,
characterised by each fixing element (1 and 1a) encircling, either partially or wholly, the protruding end with which it is mechanically associated.
Bucket (A) as per patent claim 3,
characterised by each fixing element (1 and 1a) having one or more outward facing tongues (1 a).
Bucket (A) as per patent claim 4,
characterised by at least one tongue (1a) pointing downwards along the mechanically associated sidewall (11) and towards the sidewall's (11) joint with the bucket (A) bottom (14).
Bucket as per one or more of the preceding patent claims,
characterised by each fixing element (1 and 1 a) being either partially or wholly fixed (e.g. by welds) to the mechanically associated parts (12 and 13) of the bucket (A).