Patent Application
20240052606
The invention is comprised in the field of earth moving machines, for example, excavators, provided with replaceable wear elements that contact the earth to perform works, such as excavation works. In the field of the art, these wear elements are also known with the name ground engaging tools (GETs). They comprise elements such as:
More specifically, the invention relates to a capsule for protecting an electronic device inside a wear element of an earth moving machine, having a central axis defining an axial direction, a front end, and a rear end opposite said front end in the axial direction. Electronic devices of this type are generally intended for monitoring operative parameters of the wear element, for example, for detecting accumulated wear of the element, for detecting the falling of said element, or for accumulating operation readings for subsequent analysis.
The invention also relates to a wear element comprising an electronic device protected by one of said capsules, and an earth moving machine comprising at least one of said wear elements incorporating said capsule.
In the sector of earth moving machines, wear elements, GETs, are starting to be provided with different types of electronic devices arranged therein. These electronic devices usually comprise sensors which are used to monitor or gather information about the operations of each wear element.
These wear elements are subjected to extreme working conditions: they are exposed to high pressures and end up withstanding high temperatures due to the friction of the wear element itself. For these reasons, there is a need to cover the electronic devices with a protective element, for example, a capsule intended for containing the electronic device. This capsule is formed complementary to an opening provided in the wear element intended for receiving the capsule.
Due to the working conditions, the capsule can end up with deformations which may even affect the electronic device. For example, dust or small particles of material are released during erosion or excavation works. These particles, known in the art as “fines,” enter the exposed parts of the machinery, for example, in the attachment between the wear element and the part of the machine where said wear element is coupled, for example, between the attachment of a tooth and a tooth holder. Given that the wear end of the wear element is intended for wearing off with use, the capsule with the electronic device is usually located in the area of this attachment part between the wear element and the machine. The build-up of particles in this attachment part, together with the wear element repetitively hitting the ground during use, gradually compacts said particles, which increases pressure against the capsule and can end up deforming or even destroying it, affecting the device. Furthermore, due to their small size, the particles can also enter any inner cavity, for example, between the wear element and the capsule. All this hinders the use of electronic devices inside the wear elements.
Even if the capsule is robust enough to protect the electronic device, the effect of compacting the particles described above can end up applying so much pressure on the capsule that it is impossible to extract said capsule at the end of the service life of the wear element. The particles compacted between the wear element and the capsule also contribute to this problem, given that fines are compacted to a very high level of hardness retaining the capsule inside the wear element. This effect can be aggravated by possible capsule deformations which further hinder capsule extraction.
The fact that the capsule is fixed inside the wear element has several drawbacks. The main drawback lies in recycling, given that electronic components are not recycled the same way as the metallic material with which the wear element is manufactured. The recycling problem is particularly relevant in the case where the electronic device comprises some kind of battery. To solve this problem, one option is to destroy the capsule when use thereof has come to an end to enable extracting remnants of the destroyed capsule from inside the wear element. However, there is a risk that the batteries will end up being destroyed, which would release the contaminant products they contain.
Another drawback is the difficulty in recovering the electronic device, maintaining its integrity, when its service life has come to an end. That is particularly important for those devices that must be recovered, such as those that gather operation measurements of the wear element for subsequent study. Indeed, if the capsule and its contents are to be destroyed for extraction, the use of electronic devices of this type will be impossible.
There is therefore a need for a capsule which protects the electronic device during use of the wear element, and, where possible, allows recovering said electronic device when its service life has come to an end, maintaining the physical integrity of the electronic device during use, and, where possible, also during extraction. Another objective is to minimize recycling problems.
Unless specified otherwise, this document will make use of the coordinate system relative to the capsule described above and defined by said central direction, said front end, and said rear end. The skilled person will understand that the choice of the terms “front” and “rear” is used herein for the sake of clarity to establish a reference coordinate system. However, given the nature of the capsule and its usage positions, this choice of terms is, in fact, arbitrary and other terms could be used for the coordinates. In the naming convention used herein, references to the term “front” shall be understood to be relative to said front end, whereas references to the term “rear” are relative to said rear end. For example, when talking about the front end of an element of the capsule, it will refer to the end of the element closest to the front end of said capsule, whereas when talking about the rear end of an element of the capsule, it will refer to the end of the element closest to the rear end of said capsule. Concepts such as front part, rear part, front side, rear side, front face, rear face, etc., will be understood the same way. Moreover, the term “longitudinal” must be interpreted as being relative to the axial direction, but it may not be completely parallel to said direction. For example, it can be slightly oblique with respect to said axial direction.
The purpose of the invention is to provide a protective capsule of the type indicated above, which allows solving the problems described above.
This purpose is fulfilled by means of a capsule of the type indicated above, characterized in that it comprises:
Splitting the capsule into an inner container and an outer cover covering the inner container provides the capsule with greater tolerance to the working conditions of the wear element. The cover of the invention is coupled to said container by means of any removable coupling means known in the art, such as a snap-fit or click-fit. Therefore, the possible deformations mainly affect the cover, whereas the inside of the container is less affected. In turn, the rear face of the flange is in contact with a support surface in the wear element. The flange at the front end therefore has the technical effect of attenuating the forces due to pressure exerted by the particles built up between the wear element and the machine, and deviating part of said forces to said support surface of the wear element instead of the capsule itself. Furthermore, it hinders the passage of particles to the contact areas between the capsule and the wear element, which further reduces the problems associated with compaction. The capsule is therefore more suitable for protecting the electronic device.
Preferred embodiments the features of which are set forth in the dependent claims have been provided based on the invention defined in the main claim.
Preferably, said flange has extraction means configured for extracting said container from said wear element. In this manner, even if the capsule cannot be extracted directly from the wear element, the extraction means allow extracting the container which is the part containing the electronic device. In this case, only the cover, instead of the whole capsule, would remain inside the wear element, unlike what occurs in the products of the known state of the art. This solution also favors the ability to maintain the integrity of the electronic device, even when the capsule is removed from the wear element.
Preferably, said extraction means are additionally configured for extracting said container from said cover. This further facilitates the extraction of the container: indirectly by means of extracting the container from the cover, and directly by means of extracting the container from the wear element. This minimizes the possibility of the container being lodged inside the wear element.
Preferably, said extraction means are configured for extracting said container by means of pushing in the axial direction, which facilitates a smooth extraction, minimizing the possibility of generating lateral pushes which may end up causing damage to the container or its contents, and which may furthermore cause it to become lodged during extraction.
Preferably, said extraction means comprise at least two threaded through holes, which allows extracting said container in the following manner:
Generally, when more threaded holes are provided, the force equilibrium that can be obtained during extraction will be greater, so said extraction is smoother. In contrast, with more threaded holes, the flange will have less structural integrity and the extraction will require more steps given that more screws must be tightened. Preferably, said extraction means comprise three threaded through holes, such that an optimum trade-off is obtained between the conditioning factors described above.
Preferably, said threaded holes are arranged in the axial direction parallel to said central axis, which allows extraction by means of axial pushes, such that said extraction is smoother.
Preferably, said threaded holes are all arranged at the same distance from said central axis, preferably separated from one another at regular intervals, which allows a homogeneous force equilibrium during extraction. The skilled person will understand that regular intervals refer to fact that the threaded holes, which are contiguous in a circumferential direction with respect to the central axis, are arranged at the same distance from one another. For example, in the case of a circumferentially symmetrical flange with three holes, each of these holes would be located at 120°.
Preferably, said container is open at its rear end, which facilitates the introduction of the electronic device in the capsule, given that the capsule does not have to be molded around said electronic device. Therefore, it is possible to introduce the electronic device in the container and then cover the container with the cover, thereby closing the compartment containing the electronic device.
Preferably, the capsule has a diameter with respect to said central axis that decreases, preferably in a uniform manner, between said front end and said rear end of said capsule, facilitating both the introduction of the capsule in and the extraction thereof from the device.
Preferably, the capsule has a frustum shape such that the inner part thereof can house the device, minimizing at the same time the length in the axial direction. Preferably, the capsule has a frustoconical shape which simplifies the design and facilitates extraction, particularly if the capsule did not undergo deformations.
Preferably, the capsule further comprises first positioning means configured for cooperating with respective positioning means of said wear element for positioning said capsule inside said wear element. This is particularly advantageous when the capsule must be positioned in a specific position with respect to the wear element, for example, in the case where the electronic device comprises elements that require specific relative positions. Preferably, said positioning means of said capsule comprise the outer shape of said capsule, and said respective positioning means of said wear element comprise an opening intended for receiving said capsule having a shape complementary to the shape of said capsule.
In an advantageous embodiment, said first positioning means are provided on said flange. This has the advantage of being able to create capsules with circumferentially symmetrical shapes with respect to the central axis, and at same the time precisely positioning the capsule in the wear element. In the case where the opening of the wear element where the capsule is introduced is made by machining, the use of circumferentially symmetrical shapes also simplifies machining. Preferably, said positioning means comprise the shape of the flange, particularly for an advantageous embodiment in the case of a capsule with circumferential symmetry, the flange is in the form of a circumference with a substantially straight arch on its periphery acting as positioning means by means of the complementary shape in said wear element. Other preferred shapes have other positioning means such as recesses or notches intended for the same function.
Preferably, said capsule further comprises second positioning means configured for cooperating with respective positioning means of said electronic device for positioning said electronic device inside said capsule. This is advantageous when said electronic device must be positioned in a specific manner with respect to the capsule. It is particularly advantageous in combination with said first positioning means of said capsule with respect to said wear element. Indeed, in these cases, the combination allows a precise positioning of the electronic device inside the wear element, which may be required for the case where the device has elements such as positioning sensors, directional antennas, etc. Preferably, said second positioning means comprise a rib in the axial direction configured for fitting into a groove complementary to said rib provided in said electronic device.
Preferably, said capsule further comprises capsule fixing means configured for fixing said capsule to said wear element. The presence of extraction means allows using the fixing means which would otherwise hinder the extraction of the capsule. Therefore, safety is improved and the risk of the capsule falling during transport is minimized.
Preferably, said capsule fixing means comprise projections provided on the perimeter of said flange, which allows snap-fitting into the part of the flange. Preferably, said projections are longitudinally arranged, perpendicular to said perimeter. Therefore, in the case where the flange is substantially cylindrical, said projections extend in the axial direction, parallel to the central axis. If the flange has a frustum shape, the projections are arranged in a longitudinal manner, but oblique to the axial direction. This arrangement facilitates the insertion and extraction of the capsule while at the same time providing a level of coupling suitable for common wear element handling operations.
Preferably, said capsule is manufactured in a polymer material, which facilitates its manufacture and minimizes costs, while at the same time providing a suitable level of protection. Preferably, said material is biodegradable such that in the event that the cover cannot be removed, it will break down, minimizing the environmental impact. Preferably, the material used to manufacture the capsule has a water absorption of less than 10% measured according to the norm ISO 62:2008 published on February 2008. Due to the working conditions, the wear element is sometimes exposed to water. For example, due to the climatic conditions or the water accumulated in the ground that is being engaged. Water absorption can alter the physical and/or the electrical characteristics of the material of the capsule. This can lead to undesired consequences like a decrement of the ability of the capsule to support physical stress, changes in size (bloating), etc. In addition, if the device contained in the capsule needs external communication, for example using electro-magnetic fields, changes in electrical conductivity due to the water absorption can lead to higher levels of attenuation, thereby deteriorating said communication. Preferably the water absorption is less than 1%, and more preferably less than 0.5%, further minimizing the aforementioned effects.
Preferably, said material has a moisture absorption of less than 4%, measured according to the norm ISO 62:2008 published on February 2008. Environment moisture can also be absorbed by the material leading to effects equivalent to those of water. Moisture levels can have a great variability in different locations, in particular, between the place of manufacture of the capsule or the wear element, and the place where the earth moving machine is operating. Therefore, minimizing the amount of moisture absorption is particularly relevant in order to grant the quality of the capsule and its contained device. Preferably, said moisture absorption is less than 0.2%, further minimizing the aforementioned effects.
Preferably, said material has a dielectric constant equal or less than 5, preferably, equal or less than 4, which is particularly advantageous for the cases where the device protected by the capsule is provided with an antenna for external communications. This kind of elements often need impedance matching and it has been found that it can be adversely affected by the dielectric characteristics of the material of the capsule.
Preferably, said material has a dielectric loss coefficient equal or less than 0.03, preferably, equal or less than 0.005, in order to minimize the dissipation of electromagnetic energy which is particularly advantageous when the capsule contains a device that uses electromagnetic energy to communicate with the exterior, for example, for sending or receiving information.
Preferably, said material comprises at least one of the list consisting in:
PA6 and PA6.6, also referred as PA66 or PA6,6, are widely used polymers having advantageous mechanical and dielectric characteristics. Typically, PA6 has a dielectric constant of 3.2 and a dielectric loss coefficient of 0.026. PEEK typically has the same dielectric constant as PA6, ie. 3.2, but a much lower dielectric loss coefficient, about 0.004. In addition, PEEK has a low water and moisture absorption, respectively 0.5% and 0.1%, thus having the aforementioned advantages. PPS has a very low water absorption, around 0.02%. Moisture absorption is negligible for PPS.
Preferably, said material further comprises a glass fiber filler. Glass fiber fillers, often referred as GF, confer advantageous characteristics to the polymeric materials. In particular, adding a glass fiber filler allows preventing brittle behavior in cold environments, and significantly reduce the softening behavior of the polymers that typically occurs at high temperatures. Said softening is particularly relevant at high temperatures compared to ambient temperature conditions because the polymers are often in constant deformation even at lower stress levels. These two technical effects are particularly relevant since the capsule is exposed to working or environmental conditions that can typically range from −50° C. to 200° C. Therefore, adding a glass fiber filler improves the robustness of the capsule in the whole range of temperatures to which the capsule is exposed. Besides, adding glass fiber also typically improves the dielectric behavior since the resulting material often has a lower dielectric loss coefficient. In addition, the glass fiber filler decreases the water and/or moisture absorption. Therefore, adding a glass fiber filler to the polymeric material is particularly advantageous for manufacturing the capsule of the invention. Preferably, the material has 30% by weight of glass fiber filler, which is a common percentage in the market offered by the manufacturers of polymers. As an example, a common notation for a PPS polymer with 30% of added glass fiber filler is PPS+30% GF.
Preferably, said container and said cover are configured so that when said cover is coupled to said container said cover covers said container up to the rear end of said flange. During the extraction operation from the wear element, the container slides inside the cover and said sliding movement is between two materials with small friction, for example, plastic materials, instead of sliding along the metal material of the wear element. Therefore, the extraction is facilitated due to a decrease of friction.
In an alternative embodiment, said container and said cover are configured so that when said cover is coupled to said container said cover is spaced from said flange. The spaced section of the container can thus have a thicker wall without incrementing the external volume of the capsule. This configuration is particularly advantageous in the case where the inner chamber extends in the flange part of the container. In these cases, the capsule is debilitated in the walls near the front end of the inner chamber. Providing a thicker wall section in this zone improves the strength of the capsule. Preferably, the container comprises a wall part provided in the spacing between the rear end of the flange and the cover, which is preferably configured to follow the shape of the cover.
Preferably, said rear part is an oval base frustum. In the context of this invention the term “oval” or “oval shape” stands for closed curves that resemble circles flattened in one of its axis, for example, ovals, ellipses, stadiums or the like, being regular and irregular. The frustum shape extends in said axial direction. Said slim and flattened shape facilitates the incorporation of the capsule in wear elements having a flat shape. In addition, the frustum shape facilitates the extraction of the capsule from the wear element. Finally, the shape also facilitates the orientation of the capsule, therefore acting as positioning means.
Preferably, said flange is an oval base frustum, extending in said axial direction, thus having equivalent advantages that the case of the rear part described above.
Preferably, said capsule further comprises a metal washer arranged at the rear end of said flange, so that said metal washer is interposed between said flange and said wear element when said capsule is inserted in said wear element; said washer having at least two threaded through holes. Said holes are preferably provided at opposite ends of the washer, and have the equivalent function as the extraction means of the flange that have been described above. The skilled person will understand that providing more than two holes facilitates the extraction but weakens the washer, in particular if the holes are too close to one another. Therefore, said skilled person will have no problems in deciding the number of threaded holes in the washer depending on the size and shape of said washer. Providing a metal washer with threaded through holes solve the problem of deformations in the holes of the washer due to the harsh working conditions. Said deformations can lead to unusable threaded holes that could difficult the extraction of the capsule from the wear element. In the cases where the threaded holes are provided in the flange, deformations occur more easily, since that flange is often made of a softer material. Nevertheless, said softer materials such polymers are advantageous since they provide a good thermal and shock isolation for the device inside the capsule. The usage of a separate metal washer solves the issue of extraction without limiting the desired isolation level. In some alternative embodiments, metal inserts are used instead of a metal washer, nevertheless, the washer is a preferred embodiment because it facilitates the distribution of the extraction forces.
Preferably, said flange extends over said threaded through holes, said flange provided with corresponding access holes for accessing said threaded through holes from the front end of said flange. Therefore, the surface contacting the flange with the metal washer is maximized, thus facilitating the extraction operation.
In alternative embodiment, said flange does not extend over said threaded through holes, thus minimizing the possibility that deformations in the flange due to the harsh working conditions could block the access to the threaded holes in the metal washer.
The invention also relates to a wear element, GET, comprising an electronic device protected by a capsule according to any of the embodiments indicated above. The capsule is preferably arranged in an opening located inside the wear element.
The invention also relates to an earth moving machine comprising at least one wear element of the type described above. Preferably, said machine is an excavator comprising a shovel provided with several of said wear elements.
The invention also covers other detail features illustrated in the detailed description of an embodiment of the invention and in the attached drawings.
The advantages and features of the invention can be seen from the following description in which preferred embodiments of the invention are described in a non-limiting manner with respect to the scope of the main claim in reference to the drawings.
The drawings show an embodiment of a capsule 1 for protecting an electronic device 2 inside a wear element 3 of an earth moving machine. It can be seen in
The capsule 1 with the electronic device 2 is shown in
The capsule 1 of the drawings comprises a container 5 shown separately in
For the example of the drawings, the container 5 is open at its rear end such that the electronic device 2 can be introduced into said container 5 through its rear end. In other embodiments, the rear end of the container 5 is not open.
The capsule also comprises a cover 6 that can be removably coupled to said container 5 and configured for covering said rear part 52 of said container 5. For the example, the rear part 52 of the container 5 has an annular recess 54 in the area where it is attached with the front part 51. In turn, the cover 6 has an annular protuberance 64 at its front end. Said annular recess 54 and said annular protuberance 64 cooperate with one another as coupling means, allowing the cover 6 to be removably coupled to the container 5. Other embodiments have several of said annular recesses in the rear part 52 and several corresponding annular protuberances in the cover 6, thereby achieving a stronger coupling. Other embodiments have other types of coupling between the cover 6 and the container 5.
Therefore, in the examples of the drawings, the cover 6 covers the container 5 right up to the rear end of the flange 7: the container 5 can be inserted into the cover 6 and said cover 6 acts like a cap, tightly covering the container 5. A section view showing the interaction and the relative positions between the container 5 and the cover 6 can be seen in
For the embodiment of the drawings, said flange 7 has extraction means 10 configured for extracting said container 5 from said wear element 3. Other embodiments do not have extraction means 10.
For the example of the drawings, the extraction means 10 comprise three threaded through holes in the axial direction located at regular intervals of 120° and at the same distance from the central axis 4, all of them being parallel to said central axis 4, as shown in
For some embodiments such as the one shown in the drawings, the capsule 1 further comprises first positioning means 11 configured for cooperating with respective positioning means of said wear element 3 for positioning said capsule 1 inside said wear element 3.
In some embodiments like the one shown in
In some advantageous embodiments like the one shown in the drawings, the capsule 1 further comprises capsule fixing means 13 configured for fixing said capsule 1 to said wear element 3. In particular, for the example said capsule fixing means 13 comprise scores provided on the perimeter of said flange 7, arranged perpendicular to said perimeter. In the example, given that the flange has a slightly frustoconical profile, the scores extend axially, not completely parallel to the central axis 4, but rather slightly oblique thereto.
In some embodiments, the capsule 1 is manufactured in a polymer material such as polyamide. In other embodiments, the capsule is manufactured in polyamide with glass fiber filler, particularly PA6.6+30% GF. In other embodiments, the material is biodegradable.
In the embodiments shown in the
In other embodiments, the capsule 1 is made of PA6, PA6.6 or PEEK. In some of the embodiments, the material also includes a glass fiber filler. Some of the latter include a 30% by weight of glass fiber filler.
By contrast,
The
The
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/ES2020/058784 | 3/27/2020 | WO |
