The invention relates to a coupling element for connecting a bucket element and a side element in a bucket portion in a loading machine bucket. The invention also re- lates to a system for attaching the bucket element to the bucket portion, the system comprising the coupling element and a torque element.

Background of the invention

By a loading-machine bucket is meant, in this connection, any form of bucket for dig ging or loading, for example an excavator bucket or a wheel loader bucket. The bucket in this connection typically has a width of between one and six metres.

A bucket is subjected to considerable wear and is therefore usually provided with re placeable wearing parts. A front piece is an example of a wearing part for a bucket. Even if the front piece may be provided with wearing strips or similar protective ele ments that are designed to extend the life of the front piece, it is necessary, varying intervals, to carry out replacement of the front piece.

The front piece has a top side, a bottom side, a front portion and a rear abutment face. In a fully assembled bucket, the rear abutment face of the front piece abuts against a corresponding, front abutment face belonging to a bucket body, also known as a bucket bottom. It is known to weld the front piece to the bucket body along the rear abutment face. An alternative method of attachment is screwing the wearing part, the front piece in this example, to a coupling plate which has been welded to the bottom side of the bucket body, and which extends forwards from the front abutment face of the bucket body.

The applicant's own unpublished patent document NO20171975 discloses an attach- ment for a bucket front on a digging bucket, in which side elements form coupling por- tions for the bucket front, and in which several first cut-outs extend into the side ele ment, and a bolt hole extends through the coupling portion transversely to the longi tudinal direction of said cut-outs, and in which the bucket front is provided with sever al through second cut-outs for receiving coupling pins which are arranged to extend through the bucket front and into the cut-outs of the side elements, the coupling pins being provided with projecting first end portions and second end portions provided with transverse bolt holes, and the bolt holes of the coupling pins, when the bucket front is abutting against the side elements and the coupling pins have been inserted through the bucket front into the cut-outs of the side elements, being in line with the bolt holes through the coupling portions of the side elements to be able thereby to receive respective attachment bolts.

When a bucket is being filled with a mass, for example crushed rock, the weight of the mass will typically give the bucket front a deflection, the deflection increasing with the width of the bucket and being largest in wide wheel loader buckets. Said coupling pins are subjected to a great torque and great spot loads in a lower portion of the coupling pins, the coupling pins forming a rigid connection between the bucket front and the side element. Over time, there is therefore a risk of the bolt suffering fatigue failure.

The applicant's own patent document N0333294 discloses a device for connecting a bucket front and a side portion, the side portion being formed with a coupling piece comprising at least two projections with cut-outs, the projections fitting complemen- tarily into cut-outs in the bucket front, and the bucket front being connected to the coupling piece by means of a locking bolt extending in the direction of the side portion through openings associated with the side portion and the bucket front.

The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through the features that are specified in the description below and in the claims that follow.

A general description of the invention

The invention is defined by the independent claims. The dependent claims define ad vantageous embodiments of the invention.

In a first aspect, the invention relates, more specifically, to a coupling element for connecting a bucket element and a side element in a bucket portion for a loading- machine bucket, the side element being arranged to abut against a top side belonging to the bucket element. The bucket element has a bottom side with an elongated re cess with a centre axis, and the elongated recess surrounds a through cut-out that extends to the top side of the bucket element. The coupling element comprises an elongated body arranged to lie pivotably supportingly against the recess so that the bucket element can pivot around a portion of the elongated body, and a neck for at taching to the side element, the neck projecting from the elongated body.

By a bucket element may be understood an element which forms part of a bucket por tion. The bucket portion may comprise a plurality of bucket elements that are attached to each other by the use of welds or screw connections. The torque element may be part of the bucket element. In one embodiment, the bucket element may be a front piece which is screwed to an underlying bucket element or bucket body. In another embodiment, the bucket element may be a bucket element that is screwed to an over- lying bucket element or bucket body.

The bucket element may be a bucket body connecting several bucket elements and is arranged to absorb movements in the loading machine bucket, and is normally formed of a tough material to absorb tensions due to movements and loads and thereby re duce the risk of fracture.

The bucket element may be a wearing part. The wearing part is arranged to protect a bucket body. The wearing part is normally heat-treated to resist wear. The wearing part may be positioned in front of a bucket body, on the side of the bucket body or under a bucket body. The wearing part may enclose a portion of a bucket body. The wearing part is normally replaceable.

The coupling element is adapted for connecting bucket elements in a bucket portion where a moment and/or tensions and shear forces may arise between the bucket ele ments.

By an elongated body may be understood, herein, a body with an oblong base con tour. The base contour may be rectangular. The base contour may comprise a radial sector.

The effect of the body of the coupling element being able to lie pivotably supportingly against the recess of the bucket element so that the bucket element may pivot around a portion of the body is that a connection may be provided in which tensions and shear forces between the bucket element and the side element and the coupling ele ments, if any, can be avoided. Said forces may typically arise in consequence of a torque created between the bucket element and the side element.

The torque between the bucket element and the side element typically arises when a loading machine bucket is being filled with a mass and during transport after the load ing machine bucket has been filled. A loading machine bucket which is described here is often used in mining where there are large transport distances and uneven ground. Such conditions may give large deflections and a risk of fatigue failure in a prior-art coupling portion between the bucket element and the side element.

The coupling element has a special advantage when the loading machine bucket is also used for transporting a mass. The transport often takes place on uneven ground, which may give great dynamic loads on a coupling portion between the bucket ele ment and the side element.

In a prior-art rigid coupling portion, when a bucket element in a bucket is being de flected, great tensions and shear forces will arise in the coupling portion. These ten sions and shear forces may lead to crack formations and fracture. The coupling ele ment described herein will at least reduce these tensions and shear forces so that the life of the coupling portion is extended, compared with the prior art.

The elongated body may have a semicircular surface.

The effect of the semicircular surface is that the bucket element may pivot around the coupling element without undue tensions arising. The recess may advantageously have a corresponding semicircular surface, so that a largest possible contact surface between the coupling element and the bucket element is provided.

By semicircular may be understood, herein, a rounded surface with is arranged to al low a body to abut against the surface and move along the periphery of the surface. The semicircular surface may be formed of a plurality of plane faces.

The neck may be positioned in a centre portion of the elongated body.

The effect of positioning the neck in a centre portion of the body is that the coupling element may absorb a load component on both sides of the neck, so that the coupling element is only subjected to a tensile force and not a moment when the coupling ele ment absorbs the load component.

The cross section of the neck may be smaller than the cross section of the elongated body. The effect of the cross section of the neck being smaller than the cross section of the body is that the bucket element may abut supportingly against the body along a por tion that extends along the entire semicircular surface of the body. By the bucket ele ment also abutting against a portion of the centre portion of the body, the forces are distributed more evenly along the entire body than if the bucket element only abuts against the body on each side of the neck, in the axial direction of the body.

The through cut-out of the bucket element may advantageously have a larger cross section than the neck so that the bucket element is not in contact with the neck when the bucket element is subjected to a deflection. It is thereby possible to prevent the bucket element from subjecting the neck to harmful shear forces.

The neck may be arranged perpendicularly to the elongated body.

The effect of the neck being arranged perpendicularly to the body is that the coupling element may be made symmetrical. A symmetrical coupling element has the ad vantage of the forces being distributed symmetrically and evenly along the body, and of being mountable in two different directions.

The neck may be arranged to receive a through fastening element for attachment to the side element.

The effect of attaching the coupling element to the side element with a through fas tening element is that the coupling element will have a stronger attachment to the side element compared with a one-side fastening element, as the forces are distribut ed on two sides of the neck. Further, a through fastening element will only be subject ed to shear forces, whereas a one-side fastening element will be subjected to a mo ment.

In a second aspect, the invention relates to a system for attaching a bucket element in a bucket portion for a loading machine bucket, the system comprising at least one coupling element according to the first aspect of the invention, arranged to absorb and reduce tensions and shear forces between the bucket element and a side element of the bucket portion, and at least one torque element for attaching two bucket elements to each other. Protruding from a first side of the torque element, there is an elevation which has a base contour and a smaller top contour so that, between the base contour and the top contour, at least one sloping face is provided. The elevation has a height axis at a cen tre of the elevation, the height axis being perpendicular to the base contour. The ele- vation is adapted for positioning in a corresponding cut-out in the bucket element to engage with the bucket element and is arranged to receive the screw connection along the height axis for the torque element to be attached to the bucket element.

The effect of the system described herein is that the torque element and the coupling element may simplify the installing and replacing of wearing parts in a bucket, as there is no need to connect the parts by welding, and to separate the parts by the use of grinding tools. Further, the torque element and the coupling element may eliminate or at least reduce shear tensions known to arise between adjacent parts in a bucket that is joined together in accordance with the prior art. The design of the torque element and the design of the coupling element also reduce the need for heavy special-purpose tools as the screw connection used herein has a considerably smaller dimension than is the case in the prior art. Further, the fastening element also has a dimension which is adapted for the use of a hand-held tool when being installed and removed. In what follows, examples of preferred embodiments are described, which are visual ized in the accompanying drawings, in which:

Figure la shows, in perspective and from above, one embodiment of a torque el ement;

Figure lb shows the torque element of figure la from underneath; Figure lc shows a section of the torque element of figures la and lb; Figure 2a shows, in perspective and from above, a second embodiment of the torque element;

Figure 2b shows a section of the torque element of figure 2a; Figure 3a shows a coupling element in perspective; Figure 3b shows a section of the coupling element of figure 3a; Figure 4 shows, in perspective and on a smaller scale, a simplified drawing of a bucket portion for a loading-machine bucket, with a torque element and a coupling element;

Figure 5 shows the bucket portion of figure 4 with several elements; Figure 6 shows figure 5, viewed from above;

Figure 7 shows, in perspective, a bucket portion comprising the first and second embodiments of the torque element;

Figure 8a shows, on a larger scale, a section of the first embodiment of the torque element installed in the bucket portion;

Figure 8b shows, on a larger scale, a section of the second embodiment of the torque element installed in the bucket portion;

Figure 9 shows a longitudinal section of the coupling element installed in the bucket portion; Figure 10a shows a cross section of the coupling element in an unloaded loading- machine bucket;

Figure 10b shows a cross section of the coupling element in a loaded loading- machine bucket; and

Figure 11 shows a section of figure 8a. Figures la, lb and lc show a first embodiment of a torque element 2a for absorbing shear forces in a screw connection 9 (figures 5, 8a, 8b) arranged to attach a bucket element 40, 50 in a bucket portion 1 for a loading machine bucket. The torque ele ment (2a, 2b) is not part of the invention described herein but is included to illustrate the components of the system according to the second aspect of the invention. The torque element 2a comprises a first face 220, a second face 210, and a side face 214. Protruding from the first face 220, there is an elevation 21 with a height h, a base contour 202 and a smaller top contour 204 so that, between the base contour 202 and the top contour 204, a sloping face 24 is provided. The elevation 21 has a height axis S at a centre of the elevation 21, the height axis S being perpendicular to the base contour 202 and the first face 220. In the embodiment shown, the height axis S coincides with a centre axis of the elevation 21. The elevation 21 in figures la ic is shown as a truncated cone, the contours 202, 204 being circular. The top contour 204 surrounds a top face 206 which is parallel to the first face 220. A through cut-out 29 is arranged to house a screw connection 9, shown in figures 8a and 8b. The cut-out 29 includes a conical portion 291.

The torque element 2a is shown with a square plate shape and four elevations 21 which are positioned symmetrically relative to each other. The torque element 2a is further shown with sloping side faces 214.

The torque element (2a, 2b) is not part of the invention described herein but is includ ed to illustrate the components of the system according to the second aspect of the invention.

Figures 2a and 2b show a second embodiment of the torque element 2b. The torque element 2b is shown as an elongated body with a sloping portion 212 which is ar ranged to slide against a firm surface, for example during loading by the use of a wheel-loader. The torque element 2b further comprises an abutment face 213 ar ranged to abut supportingly against a bucket body or a wearing part. The torque ele ment 2b shown in figures 2a and 2b is often positioned on the bottom side of a buck et, as shown in figure 7. The torque element 2b may be longer than, and include more elevations 21 than, what is shown in figure 2a.

The second embodiment 2b is shown with an internally threaded portion 211 which is arranged to receive a screw.

Figures 3a and 3b show a coupling element 3 for absorbing a torque between a bucket element 50 and a side element 60 in a bucket portion 1 (figures 4, 5, 6, 10a and 10b) for a loading machine bucket.

The coupling element 3 comprises an elongated body 30 with a longitudinal axis 30a, and a neck 32 projecting up from the elongated body 30. The elongated body 30 is shown with a semicircular surface 33. The neck 32 is positioned at a centre of the elongated body 30 and is shown with a cross section which is smaller than the cross section of the elongated body 30. The neck 32 includes a through cut-out 34 arranged to receive a fastening element 650, shown as a bolt in figure 9.

Figures 4, 5 and 6 show the torque element 2a and the coupling element 3 installed in the bucket portion 1, the bucket portion 1 comprising a first bucket element 40 shown as a bucket bottom 40, and a second bucket element 50 shown as a wearing part, and a side element 60 with a front protection 65 and an outer wear face 66. In what fol lows, the first bucket element 40 will be referred to as a bucket bottom. In what fol lows, the second bucket element 50 will be referred to as a wearing part. Some ele ments have been removed from figures 4 and 5 for easier illustration of the invention.

The bucket portion 1 has a centre axis S3 which coincides with a working direction A. By a working direction may be understood a direction of motion of the bucket portion 1 when the loading machine bucket is to be filled. During loading, the bucket portion 1 is moved into a mass in the working direction A and the bucket portion 1 is subjected to a force component along the centre axis S3. During loading, the bucket portion 1 may be in a plane position or in a slanted position.

The bucket bottom 40 has a top side 410, a bottom side 411 and a front abutment face 412. The top side 410 of the bucket bottom 40 includes cut-outs 41 arranged to receive elevations 21 belonging to a torque element 2a.

The wearing part 50 has a top side 510 and a rear abutment face 512 abutting against the front abutment face 412 of the bucket body. The top side 510 of the wearing part 50 includes cut-outs 41 arranged to receive elevations 21 belonging to the torque el ement 2a.

The wearing part 50 has a bottom side 511 with an elongated recess 520 (figure 9) with a centre axis which is parallel to the side element 60. The elongated recess 520 surrounds a through cut-out 530 which extends to the top side 510 of the wearing part 50.

The wearing part 50 and the bucket bottom 40 are releasably connected to each other by two torque elements 2a, each torque element comprising four screw connections 9. The torque elements 2a are shown as plate elements with a square base contour and four symmetrically positioned elevations 21, which engage with the corresponding cut outs 41 in the wearing part 50 and in the bucket bottom 40. The symmetrical design makes it possible to turn the torque elements 2a 90 or 180 degrees when worn.

The side element 60 abuts against the top side 510 of the wearing part 50 and the top side 410 of the bucket bottom 40. The elongated body 30 of the coupling element 3 is positioned in the elongated recess 520 of the wearing part 50, and the neck 32 ex tends through the through cut-out 530 in the wearing part 50 to the cut-out 610 of the side element 60. The coupling element 3 is releasably attached to the side ele ment 60 via a fastening element 650, shown as a bolt in figure 9. The fastening ele ment 650 is inserted into the side element via a cut-out 640 in the longitudinal direc tion of the side element.

Figure 7 shows an alternative embodiment of the bucket portion 1, in which the buck et portion 1 is provided with a front bucket element 50', shown in the figure as a front wearing part 50'. The front wearing part 50' is connected to the bucket portion 1 with an underlying bucket body 49 and an elongated torque element 2b, shown in figures 2a and 2b. A section of the connection is shown in figure 8b. Figure 8a shows a section D-D of the torque element 2a which is in engagement with the wearing part 50 and the bucket bottom 40. The torque element 2a is attached to the wearing part 50 and the bucket bottom 40 via two screw connections 9. The wear ing part 50 and the bucket bottom 40 are provided with threaded portions 211 for the screw connections 9. An underlying bucket body 49 is welded to the bucket bottom 40 and is arranged to support the wearing part 50.

When the wearing part 50 is subjected to a force component along the working direc tion A, an axial tensioning of the screw connections 9 will be created as the wearing part 50 will push the torque element 2a along the sloping face 24. Figure 11 shows a section of the connection shown in figure 8a.

Figure 8b shows a section of the torque element 2b which is in engagement with the wearing part 50 and the bucket bottom 40, shown in figure 7. The torque element 2b is attached to the wearing part 50 and the bucket bottom 40 via a plurality of screw connections 9. The torque element 2b is provided with an internally threaded portion 211 for the screw connection 9. Further, the torque element 2a is arranged to abut supportingly against a firm surface 99. The technical effect of the coupling between the elevation 21 and the cut-out 41 is the same as in figure 8a.

Figure 9 shows the coupling element 3 (figure 3) in a section C-C (figure 6). The cou pling element 3 is arranged to reduce or remove a torque which may arise between the wearing part 50 and the side element 60 in a bucket portion 1 for a loading- machine bucket. The side element 60 abuts against a top side 510 belonging to the wearing part 50. The wearing part 50 has a bottom side with an elongated recess 520 housing a portion of the coupling element 3. The coupling element 3 is shown with an elongated body 30 and a neck 32 which is positioned at the centre on the elongated body 30. The neck 32 projects through a through cut-out 530 (figure 4) in the wearing part 50 and into a cut-out 610 in the side element 60.

The side element 60 has a cut-out 640 for receiving a fastening element 650 for the coupling element 3. In figure 9, two fastening elements 650 are shown, shown as bolts. The fastening elements 650 comprise internally threaded portions 651 arranged to receive an installation tool (not shown). The two fastening elements 650 are held in position by means of a coupling ball 620 (figure 4) and an end piece 65 (figures 5-7).

Figures 10a and 10b show the coupling element 3 in a section E-E (figure 9). The wearing part 50 abuts against the coupling element 3. In figure 10a, the wearing part 50 is unloaded, and the wearing part 50 is positioned perpendicularly to the side ele- merit 60.

In figure 10b, the wearing part 50 is loaded by a force F so that the wearing part is subjected to a deflection. When the wearing part 50 is being deflected, the wearing part 50 will pivot around a centre axis of the semicircular surface 33 on the coupling element 3. By the wearing part 50 being able to pivot around the coupling element 3, a moment and the shear forces that arise in a prior-art rigid coupling may be reduced or eliminated.

Figure 11 shows the elevation 21 positioned in the cut-out 41, the sloping face 24 of the elevation being shown with a gentler angle than the corresponding sloping face 440 of the cut-out. A different angle as shown in figure 11 provides a defined contact surface, and thereby a locking contact surface, 408 with great surface pressure be tween the elevation 21 and the cut-out 41. When the elevation 21 and the cut-out 41 have the same shape, the contact surface 408 will be a surrounding one. In figure 11, an angular difference of two degrees is shown in order to illustrate the invention more easily.

Between the top face 206 of the elevation and the bottom contour 404 of the cut-out, a free space with a height f is created to ensure that the torque element 2a, 2b will be lying in supporting abutment against the cut-out 41 along the contact surface 408.

It should be noted that all the above-mentioned embodiments illustrate the invention, but do not limit it, and persons skilled in the art may construct many alternative em bodiments without departing from the scope of the attached claims. In the claims, reference numbers in brackets are not to be regarded as restrictive.

The use of the verb "to comprise" and its different forms does not exclude the pres ence of elements or steps that are not mentioned in the claims. The indefinite article "a" or "an" before an element does not exclude the presence of several such elements.

The fact that some features are indicated in mutually different dependent claims does not indicate that a combination of these features cannot be used with advantage.