Patent Application
20230175237
The invention relates to a change system for wear parts of an excavator bucket of an earthmoving machine, comprising a carrier structure which can be fastened to or is formed on the excavator bucket and which has a projection and also an exchange part with a pocket-like cavity, which exchange part can, by means of the cavity, be releasably plugged onto the carrier structure or onto the projection of the carrier structure formed there.
Excavator buckets of earthmoving machines are subject to extreme loads from the dug material during digging work. This is even more true of earthmoving machines in the field of mining, i.e. for surface and underground mining The buckets used there consist of a main structure made of cast steel, which are provided at wear-critical points with exchangeable wear parts as protection, which parts can then be replaced after a certain operating period. Examples of such wear parts include bucket teeth and shields in the region of the cutting edge or cutting walls of the bucket. Individual adapters for the teeth can also be of an exchangeable design. Since these wear parts are exchanged as required, their fastening to the main carrier must also be designed in a releasable manner.
The above-described systems are known on the market as so-called “ground engaging tools (GET)”. Prominent here is the design of corresponding tooth adapters on the lip of the excavator bucket, which are used to receive the actual teeth. The pushed-on teeth are fixed on the adapter by means of a socket pin, which is pushed either horizontally or vertically through the adapter. In addition to the adapter, the pin used must also withstand the occurring loads, and must therefore have relatively large dimensions. However, the disadvantage of this is that the size of the pin requires a correspondingly large pin bore hole within the tooth and also within the adapter, which can cause a weakening of the adapter structure (or tooth).
In addition, during operation, vertical or horizontal pins are subject to shear forces which can generally lead to a deformation of the pin. However, a deformed pin makes it more difficult to separate the pin connection and thus to exchange the teeth. If the pin deformation is exacerbated by the collection of bulk material and a compacting of the collected dirt in the region of the pin connection, it is possible that the pin cannot be removed at all, or only with great effort.
Furthermore, the production of the aforementioned adapters and tooth parts is associated with certain difficulties. During the production of tooth parts and adapters as cast parts, the bore holes are a critical point in the cooling process since they concentrate heat. This can lead to cooling cracks or damage during the casting process on the sand core. Holes in the structures additionally induce stress concentrations, which adversely affect the fatigue life of the parts.
Against this background, the present invention is concerned with optimizing change systems of the generic type for wear parts of an excavator bucket in order to overcome the aforementioned disadvantages.
Proposed is therefore a change system for wear parts of an excavator bucket of an earthmoving machine, primarily for earthmoving machines in the field of mining Such change systems are also called “ground engaging tools” (GET) in the technical jargon. The change system relates above all to the arrangement of a bucket tooth on an adapter of the excavator bucket. However, the invention should in no way be limited to such a connection between adapter and tooth, and can easily be applied to the arrangement of tooth parts directly on the lip of the excavator bucket. The invention is also suitable for fastening the tooth adapters themselves on the lip of the excavator bucket. Finally, the invention can also be applied to the fastening of so-called shields (covers) to the lip, more particularly in the region between the tooth adapters or on the side walls of the excavator bucket. To represent the different possibilities, we refer consistently hereinafter to a carrier structure and an exchange part releasably fastened thereto.
According to the invention, it is provided to provide at least one additional connecting member for securing or fixing the exchange part on the carrier structure, which additional connecting member is connected to the carrier structure via a first connection mechanism, and to the exchange part via a further second connecting mechanism, which is physically separated from the first connection mechanism. At least one of the two connection mechanisms is based on a releasable connection in order to ensure the exchangeability of the exchange part.
Thanks to this measure, significant modifications (such as bore holes) to the carrier structure or exchange part, which adversely affect the component durability can be dispensed with. Instead, additional material in the form of the connecting member is used for the connection. Implementing independent closure mechanisms for the connection between connecting member and carrier structure on the one hand, and between exchange part and connecting member on the other, also makes the system more resistant to occurring shear stresses.
One of the connection mechanisms can be a permanent connection, for example in the form of a welded or adhesive connection. A part combining the elements can also be designed as a single piece.
According to a preferred embodiment, one of these connection mechanisms sits on the circumferential side on either the carrier structure or exchange part. However, the circumferential-side fastening on the carrier structure is preferred, because the dimensions of the carrier structure are usually smaller than the dimensions of the exchange part plugged onto the projection of the carrier structure. One of the connection mechanisms is preferably designed in a clip-like manner, for example in a U-shape like a wedge groove, a groove and tenon connection or a dovetail connection. According to a preferred embodiment, the connecting member thus at least partially engages around the carrier structure. Ideally, the circumference of the connecting member sitting on the carrier structure approximately corresponds to the circumference of the exchange part in the connection region, i.e. the outer faces of connecting member and exchange part are approximately flush.
According to a further preferred embodiment, the second connection mechanism develops a tensile force on the connecting member, as a result of which said connecting member is pulled preferably axially towards the exchange part.
The first connection mechanism can for example be formed by one or more longitudinal grooves or vertical grooves into which corresponding guide projections of the part to be connected engage. Ideally, the orientation of the grooves is selected in accordance with the tensile force of the second connection mechanism.
According to a preferred embodiment, it is provided for the carrier structure to have one or more wedge-shaped longitudinal grooves into which one or more wedge-like guide projections of the connecting member engage. As a result of the design as longitudinal grooves, it is thereby possible for the connecting member to be displaced in the longitudinal direction on the circumference of the carrier structure, more particularly towards the plugged-on exchange part. Because of the wedge-shaped design of the grooves, the groove width is variable, and therefore ideally narrows towards the exchange part. An axial displacement of the connecting member towards the exchange part therefore leads to an increase in the force fit between groove and guide projection.
Alternatively, it can as well be provided for the longitudinal grooves to instead be formed in the region of the connecting member, more particularly on the inner side of the clip shape of the connecting member. Corresponding guide projections are then provided on the carrier structure. Here, too, the groove width narrows in the longitudinal direction, for example, and therefore in the event of an axial movement of the connecting member towards the exchange part, a form fit between carrier structure and connecting member is achieved.
According to a preferred embodiment, the aforementioned axial movement of the connecting member is generated by the second connection mechanism between connecting member and exchange part. The tensile force exerted by the connection mechanism leads to the axial displacement of the connecting member and thus to the fixing of the first connection mechanism.
A suitable second connection mechanism would more particularly be a screw connection between exchange part and connecting member. This permits the tensile force to be continuously adjusted.
The screw connection can conceivably be designed with a retensioning device. For this purpose, it is conceivable to incorporate at least one elastic component, for example a ring or disc in the region of the screw connection in order to compensate for deformations by means of the incorporated elasticity.
The screw connection between exchange part and connecting member may have one or more pocket-like recesses on the circumferential surface of the exchange part and/or on the surface of the connecting member. Components of the screw connection, such as the screw nuts or screw heads, can be embedded in such recesses in a protected manner, which more particularly reduces their contamination during the earthworks. Furthermore, components of the screw connection are prevented from projecting into the working region of the bucket in a disruptive manner.
According to a further embodiment, it can be provided for the connecting member to be secured to the carrier structure and/or to the exchange part via at least one additional securing element. Said securing element serves less for isostatic fixing and more as a pure safety precaution for the event that the first and/or second connection mechanism fails. In this case, the securing element should prevent the detachment of the connecting member.
Furthermore, the connecting member can, more particularly if it is arranged on the outer circumference of the carrier structure or of the connection part, additionally serve as wear protection for the carrier structure.
In addition to the change system according to the invention, the present invention relates to an excavator bucket for an earthmoving machine, more particularly for an earthmoving machine in the field of mining, having at least one change system according to the present invention. Further details relating to the excavator bucket can therefore be dispensed with, since they correspond in full to the statements made above about the change system.
The invention also relates to an earthmoving machine having an excavator bucket according to the invention. Further statements can therefore also be dispensed with.
Further properties of the invention are to be described below based on a few exemplary embodiments, which are illustrated in the individual drawings, in which:
The present invention relates to the fastening of the individual components 2 to 5 to the excavator bucket. Hereinafter, the mechanism according to the invention is shown primarily based on the fastening of the bucket teeth 3 to the intermediate adapters 2. However, it is noted that the inventive concept is also suitable for fastening the adapters 2 to the lip 1 and for the direct fastening of any teeth 3 to the lip 1. The connection mechanism can also be used just as well for attaching the shields 4 to the lip 1, and the shields 5 to the side plates 7 of the bucket.
The tooth 3 is a wear part which must be exchanged from time to time. A releasable connection between the two components 2, 3 is therefore absolutely essential, which according to the present invention is realized with the aid of an additional component in the form of the connecting member 10. As shown in the embodiment in
A concrete exemplary embodiment can be seen in
On the inside of the side walls of the connecting member 10, longitudinal grooves 13 are formed, which in the assembly position extend to the adapter 2 in the axial direction of the tooth 3. The groove width of the longitudinal grooves 13 increases towards the tooth 3. The opposite side faces of the adapter 2 are designed with complementary guide projections 15, which also extend in the axial direction of the tooth and the width of which also increases towards the tooth 3. For assembly, the connecting member 10 is placed on the adapter 2 and there is displaced in the axial direction towards the tooth 3. As a result of the somewhat smaller groove width as compared to the width of the guide projection 14, a force fit occurs between adapter 2 and connecting member 10 the closer the latter is moved towards the tooth 3.
The connection between the tooth 3 and the connecting member 10 is established by a further independent connection mechanism. This causes a tensile force on the connecting member 10, as a result of which the connecting member is pulled towards the tooth 3.
The arrangement and form of the guide projections and longitudinal grooves can also be slightly modified. According to
The connection mechanism between connecting member 10 and tooth 3 can, as shown in
It can also be seen from the embodiment in
Minor modifications to the design of
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 109 010.2 | Apr 2020 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/057867 | 3/26/2021 | WO |
