EP2788551A1

EP2788551A1 - Mechanical system comprising a wear part and a support, and a bucket comprising at least one such mechanical system

Info

Publication number: EP2788551A1
Application number: EP12808296.3A
Authority: EP
Inventors: Fabrice MARCHAND
Original assignee: Safe Metal SAS
Current assignee: Safe Metal SAS
Priority date: 2011-12-08
Filing date: 2012-12-07
Publication date: 2014-10-15
Anticipated expiration: 2032-12-07
Also published as: MX2014006859A; KR101988399B1; AU2012350270A1; CN104114779B; FR2983880A1; ES2613849T3; WO2013083812A1; CA2858127C; RU2014127693A; ZA201404107B; US9290915B2; JP6224614B2; CO7101200A2; EP2788551B1; BR112014013811A8; RU2606724C2; FR2983880B1; BR112014013811A2; US20140360062A1; CN104114779A

Abstract

The present invention relates to a mechanical system (1), comprising a wear part (10) and a support (20), which belong to the equipment of a construction machine. The support (20) comprises a base (22), a nose (30), which extends from the base (22) along a main axis (X30), and to each side of the base (22), a housing (24) for receiving a lug belonging to the wear part (10). The mechanical system (1) is characterised in that the nose (30) comprises a first area (40), which is located in the vicinity of the proximal end (31) of the nose (30) and which comprises at least six planar faces arranged in opposite pairs delimiting sections of a first type, and a second area (80), which is located in the vicinity of the distal end (33) of the nose (30) and which comprises at least six planar faces arranged in opposite pairs delimiting sections of a second type, each planar face of the second area (80) being less inclined, relative to the main axis (X30), than the planar face of the first area (40), which is located in the extension of said planar face in the proximal direction (D31).

Description

MECHANICAL SYSTEM COMPRISING A WEAR PIECE AND A SUPPORT, AND BUCKET COMPRISING AT LEAST ONE SUCH A MECHANICAL SYSTEM

The present invention relates to a mechanical system comprising a wear part and a support belonging to equipment of public works machinery. The invention also relates to a bucket of construction machinery comprising at least one such mechanical system.

The field of application of the invention is that of equipment of public works machinery, in particular buckets, buckets or other receptacles capable of scraping, removing and moving materials for the purpose of evacuation from a given place to other operating posts using public works machinery.

In known manner, a bucket comprises a driving blade equipped with wear parts provided for their ability to penetrate the material and protection of the other components of the bucket. On the attacking blades are attached adapter-holders having a profiled nose, while the wear parts are teeth or shields which are positioned by fitting on the support-adapter in a precise connection. The link is temporary to allow the replacement of wear parts after wear. The assembly of the mechanical system including a tooth and its support is generally performed, on the one hand, by complementary shapes between the nose of the support and an inner recess of the tooth and, on the other hand, thanks to a connecting device removable type keying. In order to meet the safety requirements in force, the connecting device is adapted to overcome the striking operations for assembly as for disassembly of the tooth.

In practice, the manufacturing tolerances impose games to allow the assembly of the tooth on its support, to which are added the games formed by the pressure setting and the wear in service of the contact zones, which leaves a possibility of movement of the tooth on its support. Consequently the horizontal, lateral, oblique or various stresses inherent in the applications and uses of a public works machine cause deteriorations in the tooth-nose relationship, but also on the locking device. In addition, the profile of the nose determines the inner profile of the tooth, and therefore the presence and importance of localized weakening areas of this tooth.

WO-A-2006 059 043 and WO-A-2004 057 1 17 disclose mechanical systems each comprising a tooth, a support and a locking device. Each support includes a nose fitting of the tooth. In WO-A-2006 059 043, corresponding to the preamble of claim 1, the support also comprises ear receiving housings belonging to the tooth. Each housing has an open side and three closed sides, while the corresponding ear comprises three substantially flat faces. In practice, the upper and lower faces of the ear are locked against the upper and lower sides of the housing. This configuration effectively prevents the tilting of the tooth relative to the support under the action of a digging force, which represents the main mechanical stress likely to be experienced by the tooth in use. The profile of the nose is satisfactory, but can be improved.

In WO-A-2004 057117, the nose has planar surfaces connected by rounded offsets, in a configuration which is not entirely satisfactory in terms of resistance to in-service stresses. In particular the tip of the nose has a parallelepiped profile, which creates significant areas of weakness inside the tooth. Furthermore, rounded ears are formed on the support and received in rounded orifices of the tooth, which is not satisfactory when applying a digging force on the tooth.

The object of the present invention is to provide an improved mechanical system, having a longer life compared to existing devices.

To this end, the subject of the invention is a mechanical system, comprising a wear part and a support belonging to a piece of equipment of public works machinery, the support comprising:

- a base,

a nose extending from the base along a main axis, between a proximal end close to the base and a distal end opposite the base, the nose having a set of sections, in planes perpendicular to the main axis, which evolve in a proximal direction by delimiting increasing or constant areas, in particular by delimiting no decreasing area, except in the presence of a housing for receiving a connection device in the nose, and

- On each side of the base, a receiving housing of an ear belonging to the wear part, the housing being formed in the base in the extension of the nose, with an open side in a distal direction and three closed sides The mechanical system is characterized in that the nose comprises:

a first zone which is situated in the vicinity of the proximal end of the nose and which comprises at least six opposite two-by-two plane faces delimiting sections of a first type, and a second zone which is situated in the vicinity of the distal end of the nose and which comprises at least six flat faces two to two opposite delimiting sections of a second type, each flat face of the second zone being less inclined, relative to to the main axis, that the plane face of the first zone which is in its prolongation in the proximal direction.

Thus, the nose has an evolutionary shape, with a progressive transition between the flat faces because of their large number and their relative inclinations. The invention makes it possible to reduce the zones of concentrations of mechanical stresses within the mechanical system, and thus to improve the service life of this system, both of the tooth and of its support. In each zone, some planar faces are planned to collect forces in service, while other planar faces are planned to reduce the stress concentrations and the mass of the nose. For an equivalent weight of the support, the nose has less material, which allows to have more material on the attachment of the support to the bucket and further improves its life. Also, a less bulky nose makes it possible to make a less bulky tooth in height, which facilitates the penetration of the tooth-support-bucket assembly in the material. Finally, the ratio of the mass of the used tooth to the mass of the new tooth is improved compared to existing systems.

According to other advantageous features of the invention, taken separately or in combination:

The first zone of the nose comprises at least eight flat faces two to two opposite, at least some of the opposite planar faces being preferably parallel to each other.

- The second zone of the nose comprises at least six flat faces two by two parallel, preferably at least eight flat faces two by two parallel.

- The nose has a third intermediate zone between the first zone and the second zone of the nose along the main axis, the third zone comprising at least six opposing two faces delimiting sections of a third type in perpendicular planes at the main axis, preferably at least four flat faces and four left faces two by two opposite, the areas delimited by the sections of the third type having, in the proximal direction, a growth rate greater than the growth rate of the delimited areas by the sections of the first type and the growth rate of the areas delimited by the sections of the second type.

The flat faces of the first zone, the second zone and the third zone, which are situated, on the one hand, in the same plane comprising the main axis and, on the other hand, on the same side of the main axis, are inclined relative to each other at obtuse angles between 160 and 200 degrees.

- The flat faces of the third zone comprise, on the one hand, primary faces having the same inclination with respect to the main axis as the planar faces of the first zone which are in their prolongation in the proximal direction, these primary faces being able to withstand mechanical stresses on the nose when a digging force is applied to the wear part and, secondly, secondary faces generally more inclined relative to the main axis than the flat faces of the first zone which are in their prolongation in the proximal direction.

The third zone of the nose comprises two planar faces perpendicular to a vertical plane, preferably two planar faces perpendicular to a horizontal plane, and at least four faces oriented otherwise than at right angles to both the vertical plane and to the vertical plane; in the horizontal plane.

- When a force is applied to the wear part, the support and the wear part comprise at least one contact interface among: a first contact interface located between each ear and the receiving housing of this ear, a second contact interface located between the wear part and the flat faces of the second zone which extend substantially perpendicular to the force, a third contact interface located between the wear part and the flat faces of the first zone which extend in the extension of the second contact interface in the proximal direction, if necessary a fourth contact interface located between the wear part and the flat faces of the third zone which extend in the extension of the second contact interface in the proximal direction, and a fifth contact interface located between the wear part and a flat face which is perpendicular to the main axis. pal and arranged at the distal end of the nose, the number of simultaneous contact interfaces in service is a function, on the one hand, of the direction of the force and, on the other hand, the wear of the workpiece. wear and / or support.

- The nose has at least one plane of symmetry including the main axis, including a vertical plane and / or a horizontal plane, the main axis is preferably an axis of symmetry of the nose.

The invention also relates to a bucket of construction machinery, comprising at least one mechanical system as mentioned above. In practice, the bucket generally comprises a series of supports each receiving a tooth, which behaves as a wear part and is secured to its support by a connecting device. Alternatively, other equipment of public works can also be equipped with the mechanical system according to the invention.

The invention will be better understood on reading the description which follows, given solely by way of nonlimiting example and with reference to the appended drawings in which:

- Figure 1 is an assembled perspective view of a mechanical system according to the invention, comprising a wear part mounted on a support integral with a bucket partially shown, while the connecting device between the part of wear and support is not shown;

FIG. 2 is a disassembled perspective view of the mechanical system of FIG. 1, comprising the support and the wear part;

- Figures 3 to 5 are elevational views of the support, respectively according to the arrows III, IV and V in Figure 2;

- Figures 6, 7 and 8 are sections of the support respectively along the lines VI-VI, VII-VII and VIII-VIII in Figure 5; and

FIG. 9 is a section of the support along line IX-IX in FIG.

In Figures 1 to 9 is shown a mechanical system 1 according to the invention, equipping a bucket G of public works machinery.

The mechanical system 1 comprises a wear member 10 of the tooth type, an adapter-holder 20, and a connection device between the tooth 10 and the support 20. The support 20 is integral with the cup G, while the tooth 10 is a wear part intended to be dismantled when it is too worn by the operation of the cup G. For the sake of simplification, the cup G is partially shown in FIG. 1, while the connecting device and the housings provided for the positioning of this device through the tooth 10 and the support 20 are not shown.

In order to facilitate the identification of the different parts of the system 1 in the space, a front side 2 of which the tooth 10 is located is defined, a rear side 3 of which the support 20 is located, an upper side 4 and a lower side 5 oriented respectively. opposite the ground and facing the ground when the system 1 is assembled, and a right side 6 and a left side 7 defined with respect to a rear direction 3 - before 2.

By way of nonlimiting example, the connecting device may comprise a sleeve and a key, adjustable through the tooth 10 and in a housing of the support 20. The device can pivot between, on the one hand, an insertion configuration where the sheath is fitted into the housing of the support 20 while the key has no contact with the tooth 10 and, on the other hand, a locking configuration where the key bears against the tooth 10 while the sheath supports in the housing of the support 20, forming a coupling connection between the tooth 10 and its support 20. Preferably, the connecting device extends substantially in a vertical direction directed from the top 4 downwards 5, or in a horizontal direction from left 7 to right 6, or Conversely.

The tooth 10 comprises an active part 1 1 situated forwardly 2 and a hollow part 12 oriented towards the rear 3. In a manner known per se, the active part 11 is intended to scrape and remove materials, for example from the earth or gravel, while the hollow portion 12 is provided for the fitting of the tooth 10 on the support 20. More specifically, the portion 12 comprises an inner recess, not visible in Figure 1, provided with profiled shapes d support on the support 20, as well as lugs 14 which extend towards the rear 3 of the part 12. When the mechanical system 1 is in use, the main mechanical stress experienced by the tooth 10 corresponds to a digging force Fc, represented by an arrow directed on the active part 1 1 in Figure 1. A distinction is made between the main recess exerted by the top of the tooth 10 and the secondary recess exerted by the underside of the tooth 10, the main recess being generally larger than the secondary recess.

The support 20 comprises a base 22, partially shown in Figures 1 to 5, and a fitting nose 30 adapted to be engaged in the inner recess of the tooth 10 shaped for this purpose. The portion 12 and the nose 30 comprise complementary profiled support shapes, making it possible to form a mechanical connection by fitting to the assembly and in use within the mechanical system 1. The shapes of the nose 30 are detailed below, it being understood that the inner recess of the part 12 has complementary shapes, to the set of manufacture. In addition, a housing 24 for receiving the lugs 14 of the tooth 10 is provided on each side 6 and 7 of the base 22, in the extension of the nose 30. Each housing 24 has walls located towards the rear 3, the top 4 and the bottom 5, and is open towards the front 2 in order to receive the rearwardly directed lugs 14 of the tooth 10. On assembly, the lugs 14 are received in contact upwards 4 and downwards 5 in the accommodations 24.

The nose 30 extends from the base 22 along a main axis X30, between a proximal end 31 close to the base 22 and a distal end 33 opposite the base 22, with a median portion 32 delimited between them. The proximal end 31 is located towards the rear 3, while the distal end 33 is situated towards the front 2. A proximal or rear direction D31 directed towards the rear 3 and a distal direction or before D33 directed is defined 2. The proximal direction D31 is that of the fitting of the tooth 10 on the support 20 to the mounting of the system 1, while the distal direction D33 is that of the disassembly of the tooth 10. At the distal end 33, the end of the nose 30 terminates in a flat face 34 perpendicular to the axis X30. This face 34, also called stabilizing plate, is provided to prevent tilting of the tooth 10 relative to the support 20 when the system 1 is in use.

On the nose 30 are delimited distinct areas 40, 60 and 80. The zone 40 is located near the proximal end 31, the zone 60 is located in the middle portion 32, while the zone 80 is located in the vicinity of the distal end 33. In the vicinity means that the zone 40 is closer to the end 31 than to the portion 32 and the end 33, while the zone 80 is closer to the end 33 than the portion 32 and end 31. Each of these zones 40, 60 and 80 comprises faces shaped so as, on the one hand, to withstand the mechanical stresses exerted by the tooth 10 on the nose 30 and, on the other hand, to limit the concentration of stresses in zones of localized weakening. At the proximal end 31, the zone 40 is connected to the base 22 by fillets 35. In the middle portion 32, the zone 40 is connected to the zone 60 by a transition zone 36, while the zone 60 is connected to the zone 80 by leaves 37. At the distal end 33, the zone 80 is connected to the face 34 by leaves 38. The leaves 35 and 37 are concave, while the leaves 38 are convex.

As shown in FIGS. 2 to 9, the main axis X30 is an axis of symmetry of the nose 30. A vertical plane PV extending between the top 4 and the bottom 5 is defined, passing through the main axis X30, as well as a horizontal plane PH extending between the line 6 and the left 7 through the main axis X30. The planes PV and PH are two planes of symmetry of the nose 30, but also of the housings 24. These symmetries make it possible to facilitate the manufacture of the support 20, but especially to optimize the distribution of the forces exerted by the tooth 10 on the nose 30 and in the housings 24, whatever the direction of the stresses on the mechanical system 1.

In the preferred but nonlimiting example of the figures, each of the zones 40, 60 and 80 of the nose 30 comprises eight faces two by two opposite, in symmetry with respect to the main axis X30. More specifically, each zone 40, 60 and 80 comprises an upper face 41, 61 or 81, an upper right face 42, 62 or 82, a right face 43, 63 or 83, a right lower face 44, 64 or 84, a lower face 45, 65 or 85, a lower left face 46, 66 or 86, a left face 47, 67 or 87 and a left upper face 48, 68 or 88. The profile of each zone 40, 60 and 80 the nose 30 can therefore be generally described as octagonal: considering various transverse sections to the axis X30 in these zones 40, 60 and 80, as represented in FIGS. 6 to 8, the nose 30 in section has eight main sides connected by time off. In the proximal zone 40, the faces 41 to 48 are opposed in pairs relative to the axis X30: 41 and 45, 42 and 46, 43 and 47, 44 and 48. The faces 41 -48 are flat and connected between they leave 49 convex. The faces 41 -48 approach the axis X30 in the distal direction D33 and move away from the axis X30 in the proximal direction D31. The faces 41 and 45 are each inclined at an angle γ1 of 13 ° with respect to the axis X30 and the horizontal plane PH. The faces 42, 44, 46 and 48 are each inclined at an angle γ2 of 13 ° with respect to the axis X30. The faces 43 and 47 are each inclined at an angle γ3 of 2 ° with respect to the axis X30 and the vertical plane PV. In practice, the angles γ1, γ2 and γ3 can be respectively between 10 ° and 20 °, 12.5 ° and 17.5 °, 0 ° and 5 ° inclusive.

In the middle zone 60, the faces 61 to 68 are opposed in pairs relative to the axis X30: 61 and 65, 62 and 66, 63 and 67, 64 and 68. The faces 61 -68 are interconnected by substantially convex fillets 69. The faces 61 -68 approach the axis X30 in the distal direction D33 and move away from the axis X30 in the proximal direction D31. The faces 61, 63, 65 and 67 are flat, while the faces 62, 64, 66 and 68 are left, more precisely twisted. In other words, the inclination of each of the faces 62, 64, 66 and 68 relative to the planes PV and PH varies along the axis X30. The faces 61 and 65 are each inclined at an angle 81 of 16 ° with respect to the axis X30 and the horizontal plane PH. For each face 62, 64, 66 and 68, an average plane of this face is defined, the mean plane delimiting the same volume between the face and itself on each of its sides. In the nonlimiting example of the figures, the mean planes of the faces 62, 64, 66 and 68 are each inclined at an angle 82 of 20 ° with respect to the axis X30. The faces 63 and 67 are each inclined at an angle 83 of 20 ° with respect to the axis X30 and the vertical plane PV. In practice, the angles 81, 82 and 83 may be respectively between 15 ° and 20 °, 15 ° and 25 °, 15 ° and 25 ° inclusive.

At this stage, it is noted that the flat faces 61 and 65 have the same inclination with respect to the plane PH and the axis X30 as the planar faces 41 and 45 which are in their extension in the proximal direction D31. These faces 61 and 65 are those which have, among all the flat faces of the nose 30, each the largest bearing surface between the nose 30 and the tooth 10. These faces 61 and 65 may be described as primary faces of the zone 60 and are able to withstand mechanical stresses applied to the nose 30 when the digging force Fc is applied to the tooth 10. The faces 62, 63, 64, 66, 67 and 68 can be qualified as secondary faces of the zone 60 because they are not designed to withstand mechanical stresses on the nose 30 under the action of the digging force Fc. Due to a clearance between the nose 30 and the tooth 10 which is more important at the contact interface defined by the secondary faces than at the interface of contact defined by the primary faces, the secondary faces are not initially intended to bear against the inner recess of the hollow portion 12 of the tooth 10.

In the distal zone 80, the faces 81 to 88 are opposed in pairs relative to the axis X30: 81 and 85, 82 and 86, 83 and 87, 84 and 88. The faces 81 -88 are flat and connected between they by leaves 89 substantially convex. The faces 81 -88 approach the axis X30 in the direction D33 and move away from the axis X30 in the direction D31. The faces 81 and 85 are each inclined at an angle σ1 of 2 ° with respect to the axis X30 and the horizontal plane PH. The faces 82, 84, 86 and 88 are each inclined at an angle σ2 of 5 ° with respect to the central axis X30. The faces 83 and 87 are each inclined at an angle σ3 of 2 ° with respect to the axis X30 and the vertical plane PV. Each flat face 81 -88 of the second zone 80 is less inclined with respect to the main axis X30 than the flat face 41 -48 of the first zone 40 which is in its extension in the proximal direction D31. In practice, the angles σ1, σ2 and σ3 can be respectively between 0 ° and 5 ° inclusive.

Like the faces 61 and 65, the faces 41, 45, 81 and 85 can be called primary faces, able to withstand mechanical stresses applied to the nose 30 when the digging force Fc is applied to the tooth 10. As the faces 62, 64, 66 and 68, the faces 42, 44, 46, 48, 82, 84, 86 and 88 may be referred to as secondary faces, since they are not designed to withstand mechanical stresses applied to the nose 30 below. action of the digging force Fc. In contrast, contrary to the faces 63 and 67, the faces 43, 47, 83 and 87 are provided to withstand mechanical stresses on the nose 30 when a lateral force is applied to the tooth 10.

Particularly advantageously, the secondary faces of the different zones 40, 60 and 80 make it possible to reduce the stress concentrations within the system 1, while minimizing the overall mass of the nose 30, because of their arrangement and their particular geometry. The support 20 and the nose 30 are full, while the tooth 10 is hollow in its portion 12. For an equivalent mass of the support 20, the nose 30 has less material, which allows to have more material on the attachment of the support 20 to the bucket G and further improves its life. Also, a less bulky nose 30 makes it possible to make a less bulky tooth in height, which facilitates the penetration of the tooth-support-bucket assembly into the material. Finally, for the same external tooth profile 10, a smaller nose 30 allows more material in the tooth 10, at its inner recess. Therefore, the strength of the tooth 10 is improved, as is the ratio of the weight of the worn tooth to the mass of the new tooth. As shown in Figures 6 to 9, the nose 30 has a set of sections 50, 70 and 90, defined in planes perpendicular to the main axis X30. These sections 50, 70, 90 evolve in the proximal direction D31 by delimiting increasing or constant areas, in particular by delimiting no decreasing area. The areas considered are in fact those delimited by the envelope of the transverse sections 50, 70 and 90, it being understood that the zone 40 is likely to be traversed by the receiving housing of the connecting device, which are not represented in a purpose of simplification. The housing is provided transversely to the axis X30, preferably along the horizontal plane PH or the vertical plane PV, depending on the configuration of the mechanical system 1. The sections 50 comprising this housing have reduced areas in comparison with the adjacent housing-free sections 50, yet the areas of the cross-section envelopes 50, 70 and 90 actually evolve in an increasing or constant manner in the proximal direction D31. Apart from the compulsory presence of this housing in the nose 30, decreasing sections in the direction D31 are to be avoided, since they would materialize the presence of a zone of localized weakening of the nose 30.

The sections 50 constitute a first type of sections defined in the zone 40, the sections 90 constitute a second type of sections defined in the zone 80, while the sections 70 constitute a third type of sections defined in the zone 60. For each zone 40, 60 and 80, a growth rate of the area of the sections, respectively 50, 70 and 90, is defined per unit length along axis X30 in the proximal direction D31. The growth rate per unit length of each type of sections 50, 70 or 90 depends on the inclination of the faces in the corresponding zone, in other words depends on the angles γ1, γ2 and γ3 for the sections 50, angles δ1, δ2 and δ3 for the sections 70 and angles σ1, σ2 and σ3 for the sections 90. The growth rate of the areas delimited by the sections 70 is greater than the growth rate of the areas delimited by the sections 50, which is greater than the rate of growth. growth of the areas delimited by the sections 90, in the proximal direction D31.

Moreover, angles a1 and β1 are defined in the vertical plane PV. Each angle a1 is defined, at the surface of the nose 30, between the faces of the zones 40 and 60 which are in the plane PV on the same side of the axis X30, that is to say between the faces 41 and 61 or between the faces 45 and 65. Each angle β1 is defined, at the surface of the nose 30, between the faces of the zones 60 and 80 which are in the plane PV on the same side of the axis X30, that is to say between the faces 61 and 81 or between the faces 65 and 85. The angle a1 is between 180 ° and 200 °, in this case equal to 180 ° in the figures, while the angle β1 is between 160 ° and 180 °, in this case equal to 160 ° in the figures. Further defined is a set of planes PI which comprise the main axis X30, which are inclined with respect to the planes PV and PH and which cut the inclined faces 42, 44, 46, 48, 62, 64, 66, 68, 82 , 84, 86 and 88. By way of example, the plane PI shown in FIGS. 4 and 9 intersects the faces 42, 62 and 82 on the upper right side of the axis X30 and intersects the opposite faces 46, 66 and 86 of the lower left side of the X30 axis. A 2 and β 2 angles are also defined for a given PI plane. Each angle a2 is defined on the surface of the nose 30 between an inclined face of the zone 40 and an inclined face of the zone 60 which lie in the same plane PI and on the same side of the axis X30, for example between the face 42 and the face 62. Each angle β2 is defined, at the surface of the nose 30, between an inclined face of the zone 60 and an inclined face of the zone 80 which are in the same plane PI and on the same side of the axis X30, for example between the face 62 and the face 82. Note that the angles a2 and β2 are variable depending on the plane PI chosen, especially because of the twisted shape of the faces 62, 64, 66 and 68. Preferably, the plane PI may be chosen to be perpendicular to the mean plane, defined above, of the twisted faces. The important thing is that, whatever the plane PI chosen, the angle a2 is between 180 ° and 200 °, preferably equal to 190 °, while the angle β2 is between 160 ° and 180 °, preferably equal to 170 °. In the plane PI shown in Figures 4 and 9, the angles a2 and β2 are equal to 190 ° and 170 ° respectively.

We also define angles a3 and β3 in the horizontal plane PH. Each angle a3 is defined, at the surface of the nose 30, between the faces of the zones 40 and 60 which are in the plane PH on the same side of the axis X30, that is to say between the faces 43 and 63 or between the faces 47 and 67. Each angle β3 is defined, at the surface of the nose 30, between the faces of the zones 60 and 80 which are in the plane PH on the same side of the axis X30, that is to say between the faces 63 and 83 or between the faces 67 and 87. The angle a3 is between 180 ° and 200 °, in this case equal to 200 ° in the figures, while the angle β3 is between 160 ° and 180 °, in this case equal to 160 ° in the figures.

Whatever the longitudinal section of the nose 30 considered, all the angles between adjacent flat faces are obtuse. The flat faces 41 -61 -81, 42-62-82, 43-63-83, 44-64-84, 45-65-85, 46-66-86, 47-67-87 and 48-68-88 which are situated, on the one hand, in the same plane PV, PI or PH comprising the main axis X30 and, on the other hand, on the same side of the main axis X30, are inclined relative to each other according to obtuse angles α1, α2, α3, β1, β2 and β3 which are always between 160 and 200 °. In addition, the adjacent flat faces of the same zone 40, 60 or 80 are inclined relative to each other by at most 60 °, in planes perpendicular to the axis X30, without defining a recess entering the nose 30. The large surface area of the planar faces allows a good distribution of the forces at the interface between the nose 30 and the tooth 10. The size of the leaves or transition zones 35, 36, 37, 38, 49, 69 and 89 connecting the planar faces is reduced to the maximum.

Thus, the particular geometry of the nose 30, and therefore the internal geometry of the hollow portion 12 of the tooth 10 which results from that of the nose 30, strongly reduce the internal stress concentrations of the system 1 according to the invention, which increases its lifetime.

In practice, the application of the recessing force FC, tends to tilt the tooth 10 on its support-adapter 20. Due to the wedging of the ears 14 in the housing 24, and the presence of the stabilization plate formed by the face 34, a critical tilting of the tooth 10 can be avoided. With the wear of the mechanical system 1, the contact interfaces located between the lugs 14 and the housing 24 and between the distal end 33 of the nose 30 and the portion 12 of the tooth 10 are no longer predominant. In particular, the wall of the inner recess of the tooth 10 is likely to press very strongly on the lower part of the nose 30 under the action of the force Fc. As long as the gaps between the tooth 10 and the support 20 are small, the permitted tilting of the tooth 10 is also possible and the stresses exerted on the contact interfaces are acceptable. When the clearance between the tooth 10 and its support 20 increases, the portion 12 is likely to crack, tear or burst, making the tooth 10 out of use. Under these conditions, it is particularly advantageous to reduce the stress concentrations and thus increase the resistance of the tooth 10 to bursting.

The mechanical system 1 according to the invention is well adapted to withstand forces from all directions, in addition to the digging force Fc. When a force is applied on the tooth 10, the support 20 and the wear part 10 comprise at least one contact interface among:

a first contact interface located between each ear 14 and the housing 24 for receiving this ear 14,

a second contact interface situated between the tooth 10 and the flat faces of the zone 80 which extend substantially perpendicular to the force,

a third contact interface located between the tooth 10 and the flat faces of the zone 40 which extend in the extension of the second contact interface in the proximal direction D31,

a fourth contact interface located between the tooth 10 and the flat faces of the zone 60 which extend in the extension of the second contact interface in the proximal direction D31,

a fifth contact interface located between the tooth 10 and the flat face 34. In use, the number of simultaneous contact interfaces is a function, on the one hand, of the direction of the force exerted on the tooth 10 and, on the other hand, of the wear of the tooth 10 and / or the support 20. The contact interfaces are generally solicited in an order ranging from the first contact interface to the fifth contact interface.

Moreover, the constituent elements of the system 1 can be shaped differently without departing from the scope of the invention. In particular, the nose 30 may be shaped according to different variants detailed below. The inner recess of the tooth 10 is shaped according to the geometry of the nose 30.

In variant not shown, the nose 30 has only one plane of symmetry among the vertical plane PV or the horizontal plane PH, this plane of symmetry including the main axis X30.

According to another variant not shown, the areas 40, 60 and 80 or some of these areas of the nose 30 may have a generally hexagonal transverse profile. In this case, considering different X30 cross-sections in these particular areas 40, 60 and 80, the sectional nose 30 has six main sides connected by rounded loops.

According to another variant not shown, the nose 30 may have a transverse profile at least partly decagonal, dodecagonal, etc. In other words, at least some of the zones 40, 60 and 80 may have a number of flat faces two to two opposite who is even and over six.

According to another variant not shown, the nose 30 has by intermediate zone 60, but only areas 40 and 80 each having at least six planar faces.

According to a variant not shown, the median zone 60 of the nose 30 comprises two flat faces 61 and 65 perpendicular to the vertical plane PV, preferably two plane faces 63 and 67 perpendicular to the horizontal plane PH, and at least four faces 62, 64, 66 , 68 oriented otherwise than at right angles to both the vertical plane PV and the horizontal plane PH.

Preferably, the number of planar faces of the zone 40 is greater than or equal to the number of flat or twisted faces of the zone 60, which is greater than or equal to the number of flat faces of the zone 80, which is greater than or equal to six .

Also preferably, at least some opposite planar faces of the zone 40 and / or the zone 80 are parallel in pairs, on either side of the axis X30. For example, the faces 43 and 47 may be parallel to each other and to the plane PV. According to another example, the zone 80 may comprise six faces among which the upper face 81 facing upwards 4 and the bottom face 85 facing downwards 5 are parallel. Advantageously, the zone 80 comprises at least six or eight flat faces two by two parallel.

In addition, the connecting device between the tooth 10 and the support 20 may be of any type suitable for the present application.

The technical features of the various embodiments may be, in whole or in part, combined with one another. Thus, the mechanical system can be adapted in terms of manufacturing and operational constraints.

Thanks to the invention, the tooth 10 and the support 20 are shaped to absorb stresses of all kinds and all directions, while reducing the areas of localized weakening and wear phenomena.

Claims

1. Mechanical system (1), comprising a wear part (10) and a support (20) which belong to a piece of equipment (G) of public works machinery, the support (20) comprising:

a base (22),

a nose (30) extending from the base (22) along a main axis (X30) between a proximal end (31) close to the base (22) and a distal end (33) opposite the base ( 22), the nose having a plurality of sections (50, 70, 90), in planes perpendicular to the main axis (X30), which evolve in a proximal direction (D31) by delimiting increasing or constant areas, in particular delimiting no decreasing area, except in the presence of a receiving housing of a connecting device in the nose (30), and

- On each side of the base (22), a housing (24) for receiving an ear

(14) belonging to the wear part (10), the housing (24) being formed in the base (22) in the extension of the nose (30), with one side open in a distal direction (D33) and three closed sides,

the mechanical system (1) being characterized in that the nose (30) comprises:

a first zone (40) located in the vicinity of the proximal end

(31) of the nose (30) and which has at least six planar faces (41 -48) two by two opposite (41, 45; 42, 46; 43, 47; 44, 48) delimiting sections of a first type (50), and

a second zone (80) which is located in the vicinity of the distal end (33) of the nose (30) and which has at least six opposing flat faces (81-88) (81, 85; 82, 86 83, 87, 84, 88) delimiting sections of a second type (90), each planar face (81-88) of the second zone (80) being less inclined, with respect to the main axis (X30) , that the plane face (41 -48) of the first zone (40) which is in its extension in the proximal direction (D31).

2. Mechanical system (1) according to claim 1, characterized in that the first zone (40) of the nose (30) comprises at least eight planar faces (41 -48) two by two opposite (41, 45; 42, 46 43, 47, 44, 48), at least some of the opposite planar faces being preferably parallel to each other. Mechanical system (1) according to one of the preceding claims, characterized in that the second zone (80) of the nose (30) comprises at least six parallel flat faces (81 -88) (81, 85; 86, 83, 87, 84, 88), preferably at least eight parallel flat faces (81-88) (81, 85; 82, 86; 83, 87; 84, 88).

Mechanical system (1) according to one of the preceding claims, characterized in that the nose (30) has a third zone (60) intermediate between the first zone (40) and the second zone (80) of the nose (30). along the main axis (X30), the third zone (60) comprising at least six opposing faces (61-68) (61, 65; 62, 66; 63, 67; 64, 68) defining sections of a third type (70) in planes perpendicular to the main axis (X30), preferably at least four plane faces (61, 63, 65, 67) and four left faces (62, 64, 66, 68) two opposing pairs (61, 65, 62, 66, 63, 67, 64, 68), the areas delimited by the sections of the third type (70) having, in the proximal direction (D31), a growth rate greater than growth rate of the areas delimited by sections of the first type (50) and the growth rate of the areas delimited by sections of the second type (90).

Mechanical system (1) according to claim 4, characterized in that the plane faces (41 -48, 61 -68, 81 -88) of the first zone (40), the second zone (80) and the third zone (60) which are located, on the one hand, in the same plane (PV; PI; PH) comprising the main axis (X30) and, on the other hand, on the same side of the main axis (X30), are inclined relative to each other at obtuse angles (α1, α2, α3, β1, β2, β3) of between 160 and 200 degrees.

Mechanical system (1) according to one of claims 4 or 5, characterized in that the flat faces (61 -68) of the third zone (60) comprise:

on the one hand, primary faces (61, 65) having the same inclination with respect to the main axis (X30) as the planar faces (41, 45) of the first zone (40) which are in their extension according to the proximal direction (D31), these primary faces (61, 65) being able to withstand mechanical stresses on the nose (30) when a digging force (Fc) is applied to the wear part (10) and, on the other hand, secondary faces (62, 63, 64, 66, 67, 68) generally more inclined with respect to the main axis (X30) than plane faces (42, 43, 44, 46, 47, 48) of the first zone (40) which are in their prolongation in the proximal direction (D31).

Mechanical system (1) according to one of claims 4 to 6, characterized in that the third zone (60) of the nose (30) comprises:

two plane faces (61, 65) perpendicular to a vertical plane (PV),

preferably two plane faces (63, 67) perpendicular to a horizontal plane (PH), and

at least four faces (62, 64, 66, 68) oriented other than at right angles to both the vertical plane (PV) and the horizontal plane (PH).

Mechanical system (1) according to one of the preceding claims, characterized in that when a force (Fc) is applied to the wear part.

(10), the support (20) and the wear part (10) comprise at least one of:

a first contact interface located between each ear (14) and the housing (24) for receiving this ear (14),

a second contact interface situated between the wear part (10) and the flat faces (81, 85) of the second zone (80) which extend substantially perpendicular to the force (Fc),

a third contact interface located between the wear part (10) and the plane faces (41, 45) of the first zone (40) extending in the extension of the second contact interface in the proximal direction ( D31),

- if necessary, a fourth contact interface located between the wear part (10) and the flat faces (61, 65) of the third zone (60) extending in the extension of the second contact interface next the proximal direction (D31), and

a fifth contact interface located between the wear part (10) and a planar face (34) which is perpendicular to the main axis (X30) and arranged at the distal end (33) of the nose (30),

the number of simultaneous contact interfaces in operation being a function of the direction of the force (Fc) and of the wear part (10) and / or of the support (20).

Mechanical system (1) according to one of the preceding claims, characterized in that the nose (30) has at least one plane of symmetry (PV; PH) including the main axis (X30), in particular a vertical plane (PV) and / or a horizontal plane (PH), the main axis (X30) being preferably an axis of symmetry of the nose (30).

10. Bucket (G) of public works machine, characterized in that it comprises at least one mechanical system (1) according to one of claims 1 to 9.