Wheel forming an improved agricultural tool

Abstract

A field working tool (1) comprises a first flange (7) and a second flange (9) which are mounted one on the other forming a wheel body (3). The first flange (7) comprises a central part (71), a peripheral part (73) of generally annular shape, and at least one arm (75) connecting the central part (71) and the peripheral part (73) one to the other. The second flange (9) is homologous to the peripheral part (73) of the first flange (7). In the mounted state, the wheel body (3) has a rim (121) formed jointly by the peripheral part (73) of the first flange (7) and the second flange (9) and a hub formed by the central part ( 71) of the first flange (7).

Description

[0001] The invention relates to agricultural tools, and more particularly those comprising mainly one or more wheels.

[0002] In tools of this type, the wheel(s) are generally used to work the soil. The wheels can operate alone, or in cooperation with other parts of the tool.

[0003] In the case of a seed drill, for example, the tool includes a part designed to open a furrow in the soil, typically a share, a disc or a tine, and one or more wheels to close the furrow and / or to compact the soil, after the seeds have been placed at the bottom of the furrow.

[0004] Some implements, such as the aforementioned seed drill, also include gauge wheels, which regulate the working depth of the rest of the implement. In the case of an implement with a share, for example, gauge wheels are mounted directly to the share so that, as they roll over the soil, the wheels maintain the active part of the share at a roughly constant depth.

[0005] Most often, the wheels that equip agricultural tools are designed to roll on the ground. They therefore consist of a tire mounted around a part of the wheel that forms its body.

[0006] To prevent the tire from separating from the wheel body during manufacturing, the part of the wheel body that forms the rim is shaped in a specific way. This results in generally complex shapes, which complicate the manufacturing of the wheel body and also the mounting of the tire onto it.

[0007] This is why wheels often consist of two similar flanges that are mounted one on top of the other to form the wheel body. The flanges are joined to each other along one of their main faces, while simultaneously clamping the tire. In FR 2 933 903, the applicant proposed an innovative wheel whose wheel body shape prevents the tire from coming off the rim during operation, even under extreme conditions. The body in question is formed by the mutual assembly of two similar flanges, face to face.

[0008] When used as tools, wheels are generally subjected to significant stresses during operation.

[0009] In some cases, particularly when fitted to a seed drill, the wheel's orientation within the machine does not correspond to the machine's forward direction: frequently, the wheel is significantly inclined relative to the forward direction. Furthermore, the wheel may be inclined relative to the vertical on the ground. This results in very high stresses on the wheel body during operation.

[0010] To ensure the wheel can withstand these stresses, it is common practice to design a fairly massive wheel body. This results in a significant wheel mass, which is undesirable. A large mass increases manufacturing and shipping costs and complicates wheel mounting on the machine, particularly for cantilevered mountings.

[0011] The plaintiff has set herself the objective of improving the situation.

[0012] It proposes a working tool comprising a first flange and a second flange that are mounted one on top of the other to form a wheel body. The first flange has a central part, a peripheral part of generally annular shape, and at least one arm connecting the central and peripheral parts. The second flange is analogous to the peripheral part of the first flange. In its assembled state, the wheel body has a rim formed jointly by the peripheral part of the first flange and the second flange, and a hub formed by the central part of the first flange.

[0013] In the proposed tool, tire mounting and dismounting are facilitated by the wheel body's unique design. This wheel body offers mechanical strength at least equal to that of conventional wheels, and certainly sufficient for field work. Manufacturing the wheel body requires significantly less raw material. The proposed tool offers reduced manufacturing time and costs.

[0014] The tool may have the following optional features, alone or in combination with each other. The first and second flanges are made of two different materials. This ensures that the mechanical properties of each material are better suited to the specific functions of each flange. The second flange is made of metal. Since the second flange generally has a smaller volume of material than the first, the increase in mass compared to a second flange made of plastic remains small. The first and second flanges are made of plastic. The mass of the wheel body is then low compared to a wheel body with at least one metal flange. The second flange is formed from at least two pieces in the general shape of ring sections. The size of the equipment for manufacturing the second flange, such as the molds, can be reduced. The second flange occupies a small space before assembly, which facilitates transport.Each of the first and second flanges supports a tire mounted on the rim. The force exerted on the wheel body due to tire clamping is thus better distributed. Stress concentrations and the risk of breakage are reduced. When the two flanges are mounted one on top of the other, the hub of the first flange protrudes, at least partially, into an internal space defined by the annular shape of the second flange. The overall balance of the wheel body mounted on an axle is therefore improved. In particular, this balance can be adjusted according to the operating conditions.The outer portion of the first flange and the second flange each have an external surface whose diameter near the interface between the first and second flanges in the mounted state differs from the diameter on the side opposite the interface between the first and second flanges. This results in a rim with a generally concave or convex shape suitable for receiving a tire. The tire is held axially by the seat itself. The risk of accidental derailment is thus reduced. The outer portion of the first and second flanges are mutually shaped so that their assembly defines a groove extending substantially around the circumference of the wheel body at the interface of the outer portion of the first and second flanges. This groove is designed to accommodate a tire bead. The tire is then held radially within the groove.The risk of accidental derailment is thus reduced. The first flange is a single piece and the second flange is a single piece. Manufacturing either one or both can be accomplished in a single molding operation. The risk of breakage of either flange during operation is reduced.

[0015] Other features, details and advantages of the invention will become apparent from the detailed description below, and the accompanying drawings, in which: there figure 1 shows a perspective view of a tool according to the invention, the figure 2 shows a view of the tool of the figure 1 From another point of view, the figure 3 shows a view from one face of the tool of the figure 1 , there figure 4 shows a cross-sectional view of the tool of the figure 1 , there figure 5 shows a view similar to the figure 2 on which the wheel body is shown without a tire, the figure 6shows an exploded and perspective view of the wheel body of the figure 5 , there figure 7 shows an exploded and perspective view of a tool according to the invention, the figure 8 shows a cross-sectional view of the tool of the figure 7 on which the tool is shown without pneumatics, the figure 9 shows an exploded and perspective view of a tool according to the invention, the Figure 10 shows a cross-sectional view of the tool of the figure 9 on which the tool is shown without pneumatics, the figure 11 shows an exploded and perspective view of a tool according to the invention, in which the tool is shown without pneumatics, the figure 12 shows a cross-sectional view of the tool of the figure 11 , there figure 13 shows a view similar to the figure 2 of the tool of the figure 11 , and the figures 14A to 14D show an agricultural machine on which two tools according to the invention are mounted.

[0016] The drawings and description below contain, for the most part, elements of a definite nature. They can therefore not only serve to better explain the present invention, but also contribute to its definition, if necessary.

[0017] THE figures 1 to 4 They show a field tool in the form of a wheel 1. The wheel 1 comprises a wheel body 3 around which a tire 5 is mounted. figures 5 and 6 show the wheel body 3 of the embodiment of figures 1 to 4 before tire 5 was mounted on it.

[0018] In the rest of the description, the wheel body is referred to as (" body " Or "wheel body (in English) the practically undeformable part of the wheel, as opposed to the deformable part which is the tire. The term rim is used to refer to (" rim " Or "wheel rim(in English) the part located at the periphery of the wheel body and designed to support the tire. The rest of the wheel body can be called the wheel rim (" disc ", "wheel disc", "dish", or "wheel dish" (in English). In other words, the wheel body consists of the rim and the wheel disc. Here, the term rim cannot refer to the entire wheel body, contrary to its common, incorrect usage.

[0019] The wheel body 3 is formed of a first flange 7 and a second flange 9, generally circular. The first flange 7 and the second flange 9 are shown separately on the figure 6 , are mounted one on top of the other to form the wheel body 3 as shown on the figure 5 .

[0020] The first flange 7 and the second flange 9 each have a central axis, or axis of revolution. These central axes coincide in the assembled state and align with the axis of rotation of the wheel 1 during operation. These axes are referenced as XX in the figures.

[0021] The first flange 7 and the second flange 9 each have an inner face, 77 and 97 respectively, and an opposite outer face, 79 and 99 respectively. When the first flange 7 and the second flange 9 are assembled one on top of the other, the inner faces 77 and 97 are aligned. The outer faces 79 and 99 are oriented in opposite directions, towards the outside of the wheel body 3.

[0022] The first flange 7 and the second flange 9 are fixed, here reversibly, to each other to form the wheel body 3 by means of fasteners. In the example described here, the fasteners consist of screw-nut pairs 13. The screw-nut pairs 13 hold the first flange 7 and the second flange 9 together. Here, the screw-nut pairs 13 are distributed around the periphery of the wheel body. As an alternative or in addition, other fastening means may be used, for example, clips or rivets.

[0023] The first flange 7 has a central part 71, a peripheral part 73 and at least one arm 75 connecting the central part 71 to the peripheral part 73. Here, the first flange 7 has three arms 75.

[0024] The central part 71 has a general shape of revolution. In its assembled state, the central part 71 forms the hub of the wheel 1. The central space of the shape of revolution of the central part 71 is designed to receive an axle or spindle intended to support the wheel 1, which is free to rotate about the axis of rotation XX. The wheel 1 includes a rotating bearing housed within the central part 71, here in the form of a ball bearing 11. Alternatively, the ball bearing 11 can be replaced by other types of bearings, and more generally by a different type of bearing, such as a plain bearing, for example.

[0025] The central part 71 has an internal surface 81, generally oriented towards the main axis XX and forming, here, a bore suitable for housing the bearing 11. The central part 71 has an external surface 83, peripheral, opposite to the internal surface 81.

[0026] The peripheral part 73 is generally annular in shape. The peripheral part 73 is delimited, along the direction of the principal axis XX, by an inner edge and an outer edge. The peripheral part 73 and the central part 71 are substantially concentric and centered on the principal axis XX. The peripheral part 73 surrounds the central part 71. In the example shown on the figure 4 The peripheral part 73 and the central part 71 are offset from each other along the direction of the principal axis XX. On the side of the inner face 77 (on the left of the figure 4 ), the central part 71 projects beyond the inner edge of the peripheral part 73 along the direction of the principal axis XX, almost along the entire length of the central part 71. On the side of the external face 79 (on the right of the figure 4), the central part 71 is set back from the outer edge of the peripheral part 73. The outer end of the central part 71 is almost aligned with the inner edge of the peripheral part 73. Alternatively, the peripheral part 73 and the central part 71 can be substantially coplanar along a plane perpendicular to the principal axis XX.

[0027] The peripheral part 73 has an internal surface 91, or diametrically internal, generally oriented towards the central part 71 and an external surface 93, or diametrically external and peripheral, opposite to the internal surface 91. Here, the internal surface 91 has a general cylindrical shape interrupted by the arms 75. Here, the external surface 93 has a general annular shape, with a rounded profile and convex outwards.

[0028] Each arm 75 has an inner end 101 connected to the central part 71 at its outer surface 83, and an outer end 103, opposite the inner end 101 and connected to the peripheral part 73 at its inner surface 91. Each arm 75 thus connects the central part 71 and the peripheral part 73 to each other. The arms 75 extend radially. They form spokes of the wheel 1.

[0029] Here, the inner end 101 of each of the arms 75 is connected to the outer surface 83 substantially along the entire length of the central portion 71 in the direction of the principal axis XX. The arms 75 have a thickness, along the direction of the principal axis XX, that decreases slightly and then increases regularly from the central portion 71 to the outer end 103, where it is at its maximum and substantially equal to the thickness of the peripheral portion 73. Thus, the outer end 103 of each arm 75 is substantially identical to the peripheral portion 73 to which it is connected. The central portion 71 projects beyond the plane defined by the inner edge of the peripheral portion 73. The portion of the inner face 77 of the first flange 7 defined by the arms 75 has a generally frustoconical shape connecting the inner ends of the central portion 71 and the peripheral portion 73.The part of the external face 79 of the first flange 7 defined by the arms 75 is substantially concave, in the shape of a bowl centered on the main axis XX. The external end of the central part 71 protrudes slightly into the bottom of the bowl shape.

[0030] Spaces 78 are defined between the arms 75 and the inner surface 91 of the peripheral part 73. The distribution of the arms 75 around the central part 71 defines as many intercalated spaces 78. These spaces 78 are free and through-through along the direction of the main axis XX, from the inner face 77 to the outer face 79. In operation, the spaces 78 facilitate the evacuation of debris and mud through the first flange 7. The arms 75 and the intercalated spaces 78 together form an open wheel web.

[0031] The arms 75 are regularly spaced at angles around the main axis XX. In the examples described here, there are three arms spaced 120° apart. This configuration ensures sufficient mechanical strength for the intended applications while saving material compared to a solid wheel rim. In some variations, the number and / or arrangement of the arms 75 may differ.

[0032] In the examples described here, the first flange 7 is formed as a single piece. The first flange 7 is obtained, for example, by injection molding. The first flange 7 is made of plastic material, for example, polyamide such as polyamide 6-6, or polypropylene. The plastic first flange 7 has low raw material and manufacturing costs. However, the first flange 7 can also be made of metal. The metal first flange 7 then offers improved impact resistance, for example, in the event of stone impacts during machine movement.

[0033] As shown on the figures 2 to 6The first flange 7 can take the form of a shell reinforced by internal walls, or ribs, between which multiple cavities are left empty. The ribs give the first flange 7 good mechanical strength, comparable to a solid metal and / or plastic part. They make it possible to ensure the necessary mechanical strength with a small amount of raw material. The volume occupied by the first flange 7 is largely hollow.

[0034] If necessary, the number, distribution and shape of the ribs can be adapted according to the desired mechanical strength for the first flange 7. Finite element type modeling tools can be used.

[0035] The central part 71 houses the bearing 11. During assembly, the bearing 11 is mounted coaxially with the main axis XX of the wheel body 3. The bearing 11 is held in this position by the housing so that the main axis XX of the wheel body 3 coincides with the axis of rotation of the wheel 1 in use.

[0036] In the example described here, the inner surface 81 of the central portion 71 of the first flange 7 takes the form of a bore extending through the principal axis XX. The bore consists of three substantially cylindrical and concentric portions arranged along the direction of the principal axis XX. The central portion has a small diameter, while the inner and outer portions each have a large diameter. The two large diameters are equal. The central portion is connected to each of the inner and outer portions by a respective annular shoulder, oriented respectively towards the inner and outer sides of the first flange 7.

[0037] The bearing 11 has a shape that corresponds to the inner surface 81. The bearing 11 is formed from an assembly of at least two parts. During the installation of the bearing 11 in the inner surface 81, each of the two parts is inserted respectively from the inner and outer sides of the inner surface 81 to bear against each of the annular shoulders. Once the two parts are assembled, the two shoulders form axial stops and prevent the bearing 11 from being removed from the housing.

[0038] The second flange 9 is analogous to the peripheral part 73 of the first flange 7. The second flange 9 has a generally annular shape. The second flange 9 lacks arms and a central hub. The second flange 9 has an internal surface 111 analogous to the internal surface 91 of the first flange 7, generally oriented towards the axis of rotation XX, and an external surface 113 analogous to the external surface 93 of the first flange 7, opposite the internal surface 111. The internal surface 111 of the second flange 9 and the internal surface 91 of the first flange 7 function analogously.

[0039] In the example shown in the figures, the second flange 9 takes the form of a ring with a solid and generally triangular cross-section. One side of the triangular shape bears the external surface 113, which is homologous to the external surface 93 of the peripheral part 73 of the first flange 7. The external surface 113 has a generally annular shape, with a rounded profile and is convex outwards.

[0040] When the two flanges 7 and 9 are joined together, the spaces 78 of the first flange 7 align with the free interior space of the annular shape of the second flange 9. The spaces 78 therefore remain through-holes. The wheel body 3 has an open wheel rim.

[0041] In the examples described here, the second flange 9 is formed from a single piece. The second flange 9 is obtained by molding. The second flange 9 takes the form of a collar or peripheral rim. Alternatively, the second flange 9 can be obtained by stamping or deep drawing from sheet metal. The second flange 9 is made of metal, for example, steel. Alternatively, aluminum can be used. The second flange 9 has high mechanical strength. However, the second flange 9 can also be made of a plastic material, for example, similar to that of the first flange 7.

[0042] The first plastic flange 7 has a low manufacturing cost, while the second metal flange 9 provides the wheel body 3 with the mechanical strength required for field operation. However, both flanges 7 and 9 can be made of metal, for example, when the expected mechanical stresses are severe, or both of plastic, for example, when the expected mechanical stresses are moderate. The overall configuration of the wheel body 3, formed by the first flange 7 and the second flange 9, allows the mechanical behavior of the wheel body 3 to be adapted by changing the materials used without altering its overall configuration. Alternatively, the first flange 7 and / or the second flange 9 can be made by assembling several parts rather than as a single piece. For example, the peripheral part 73 of the first flange 7 and / or the second flange 9 can be formed from several ring sections.

[0043] Once the two flanges 7 and 9 are mutually assembled, the wheel body 3 has a rim 121 formed jointly by the peripheral portion 73 of the first flange 7 and the corresponding second flange 9 of the peripheral portion 73. The rim 121 then has an external surface formed jointly by the external surface 93 of the peripheral portion 73 of the first flange 7 and by the corresponding external surface 113 of the second flange 9. This external rim surface forms a seat 201 of the wheel body 3. The seat 201 accommodates the tire 5.

[0044] Once the tire 5 is fitted onto the rim 121, the first flange 7 and the second flange 9 support the tire 5, each approximately halfway. The area of ​​the outer surface 93 of the first flange 7 covered by the tire 5 is approximately equivalent to the corresponding area of ​​the outer surface of the second flange 9 covered by the tire 5. The first flange 7, the second flange 9, and the tire 5 are configured so that the radial force applied by the tire 5 encircling the wheel body 3 is distributed approximately equally between the two flanges 7 and 9. Neither the first flange 7 nor the second flange 9 has the sole function of blocking the tire 5 along the direction of the main axis XX. Alternatively, the force distribution can be unbalanced, for example, up to a ratio of 4 to 1.

[0045] The tire 5 comprises a tread 131 bearing against the seat 201 of the rim 121. The configurations of the tread 131 and the seat 201 are chosen to be compatible, with essentially corresponding shapes. The tire 5 is held around the wheel body 3. The risk of accidental derailment is low, even under difficult conditions.

[0046] In the examples described here, tire 5 is a semi-hollow type tire. Tire 5 is a non-inflatable type. The internal space between the sole 131 and the tread is in fluidic communication with the outside, through an opening not shown. This allows for greater deformation of tire 5 during operation, thus facilitating mud shedding.

[0047] In the embodiments shown in the figures, the seat 201 has a diameter that varies along the direction of the principal axis XX. The seat 201 has a non-strictly cylindrical shape. In the vicinity of the interface between the first flange 7 and the second flange 9, that is, in the vicinity of the internal faces 77, 97, the diameter of the seat 201 is significantly different from the diameter of the seat 201 in the vicinity of the opposite faces, that is, the external faces 79, 99. This is visible in the figures 4 , 8 , 10 And 12 In cross-section. Portions of the seat 201 thus resist the axial movement of the tire 5. The risk of accidental derailment is particularly low. The addition of a specific part forming a locking flange is superfluous.

[0048] On the methods of implementation of figures 1 to 6and, 11 and 12, in the vicinity of the interface between the first flange 7 and the second flange 9, the diameter of the seat 201 is greater than the diameter of the seat 201 in the vicinity of the opposite faces of the flanges 7 and 9, with the exception of a groove 161. The seat 201 then has a generally convex shape. This configuration allows, for example, the use of tires whose tread 131 is concave and partially surrounds a convex seat 201. Such tires are described, for example, in FR 2 933 903.

[0049] Alternatively, near the interface between the first flange 7 and the second flange 9, the diameter of the seat 201 is smaller than the diameter of the seat 201 near the opposite faces. The seat 201 then has a generally concave shape. The seat 201 has surfaces that resist the axial movement of the tire 5.

[0050] In the examples of implementation of the figures 7 to 10The peripheral part 73 of the first flange 7 and the second flange 9 are mutually shaped so that their assembly defines the groove 161. The groove 161 extends substantially over the circumference of the wheel body 3, at the interface of the peripheral part 73 of the first flange 7 and the second flange 9. The groove 161 is adapted to accommodate a corresponding bead 53 of the tire 5. The retention of the tire 5 around the wheel body 3 is further improved.

[0051] In each of the embodiments shown in the figures, the wheel body 3 is asymmetrical. In particular, the hub formed by the central portion 71 of the first flange 7 is offset from the center of the wheel body 3 along the main axis XX. The hub of the first flange 7 protrudes, at least partially, into the inner space defined by the annular shape of the second flange 9, to a greater or lesser extent depending on the embodiment. This feature is optional but allows for better balancing of the tool 1 once installed on the rest of the machine.

[0052] Tire 5 as represented in figures 1 to 4presents an asymmetrical profile. The sole 131 and the seat 201 each have a plane of symmetry perpendicular to the principal axis XX. The part of the tire 5 opposite the sole 131, the tread, is asymmetrical. The tread has a lip 55. The lip 55 projects from the tire 5, substantially along the direction of the principal axis XX, outwards, on the side of the outer face 99 of the second flange 9. The lip 55 extends substantially along the circumference of the tire 5. Such a wheel 1 fitted with a tire 5 having a lip 55 is intended to be mounted on a machine as schematically represented in the figures 14A to 14D .

[0053] The methods of implementation of figures 7 to 13 are similar to that of figures 1 to 6Functionally identical parts are designated by the same numerical references. In these embodiments, the bearing 11 comprises a double row of angular contact balls and is housed in a cartridge. The cartridge is generally cylindrical in shape. The diameter of the bearing 11 is constant, unlike the embodiment described above. The inner surface 81 of the central portion 71 of the first flange 7 is a through bore with a constant diameter along its length, extending along the main axis XX.

[0054] To the right on the figures 8 , 10 And 12In cross-section, the central portion 71 further includes an axial stop 72 configured to limit the translational movement of the bearing 11. The axial stop 72 is formed on the outer face 79 of the first flange 7. Consequently, the bearing 11 can be inserted and removed from the opposite side. The axial stop 72 allows adjustment of the bearing 11's position relative to the first flange 7. The axial stop 72 can be viewed as a bottom of the housing.

[0055] On the left of the figures 8 , 10 And 12 in cross-section and on the figure 13The wheel 1 further comprises an insert 164, or cup. The insert 164 is shaped to be fixed to the wheel body 3 by enclosing the bearing 11 housed in the central portion 71 of the first flange 7. The insert 164 has a general disc shape with a central circular opening. The insert 164 is manufactured by stamping a piece of sheet metal. In its installed state, the insert 164 partially covers the central portion 71.

[0056] The insert 164 is fixed to the open side of the housing for the bearing 11, that is, in this case, to the inner face 77. The insert 164 is secured with the screw-nut pairs 13 positioned near the center of the wheel 1. Once fixed against the central part 71, the insert 164 forms a cover for the housing and an axial stop for the bearing 11. The bearing 11 is enclosed within the housing. The opening in the center of the insert 164 allows the passage of an axle for mounting the wheel 1 on an agricultural machine. Removing the insert 164 is sufficient to open the housing and release the bearing 11. During operation, the insert 164 provides axial support for the bearing 11.

[0057] The added part 164, by at least partially covering the hub, protects it from the environment. For example, the added part 164 protects the hub and the bearing 11 housed within it from impacts caused by stones thrown up during operation. The added part 164 also protects against stresses and friction that can result from the accumulation of dried soil near the moving parts of the wheel 1. The added part 164 forms a protective shield for the hub.

[0058] THE figures 14A to 14D partially represent a 500 seed drill in which tools 1 similar to that of the figures 1 to 12Each tool cooperates with a disc 501. Tool 1 then forms a gauge wheel. Tool 1 is free to rotate but fixed to disc 501 in a substantially vertical direction. Thus, even in the presence of uneven terrain, disc 501 works at a substantially constant depth relative to the soil surface. Furthermore, the respective axes of tool 1 and disc 501 are offset from each other. As the seed drill 500 advances, the lip 55 of tool 1 scrapes against one face of disc 501, thus cleaning it of mud and debris that may have accumulated there. In this application example of tool 1, one of the two faces of tool 1 is inaccessible during operation: the side of tool 1 corresponding to the outer face 99 of the second flange 9 is difficult to access due to the presence of disc 501.

[0059] In the examples shown in the figures, the lip 55 of the tire 5 is located on the side of the second flange 9. In this configuration, a significant free space is provided inside the wheel 1 on the side of the lip 55. This free space allows, in particular, for the accommodation, partly within the internal space defined by the tire 5, of an arm 502 of an agricultural machine frame supporting an axle arranged substantially along the main axis XX. figures 14A to 14D They show an example of such an assembly. In this example, the frame arm 502 must be able to extend between the main axis XX in the vicinity of the bearing 11 and the periphery of the wheel 1. The frame arm 502 must also not interfere with the operation of the disc 501 located in contact with a part of the lip 55 and partially blocking one face of the wheel 1. In variants, the lip 55 can be located on the same side of the wheel 1 as the first flange 7, opposite the disc 501.

[0060] As can be seen in the front view of the figure 14B That is, oriented backward in the direction of travel of the 500 seed drill, the 500 seed drill has a so-called "V" configuration. Two discs 501 cooperate to cut a furrow in the soil. The two discs 501 are symmetrical to each other with respect to a vertical plane extending in the direction of travel represented by arrow A. The discs 501 are not arranged vertically but, on the contrary, are partially oriented toward the ground. For example, they form an angle of approximately 5° with the vertical. A wheel 1 cooperates with each of the discs 501. The two wheels 1 have a similar orientation to the discs 501, although the value of the angle may be different.

[0061] As can be seen in the top view of the figure 14CThe 500 seed drill also features a V-shaped configuration with a different spatial orientation. The two discs 501 also form an angle with the direction of travel of the 500 seed drill. This angle is approximately 5°. The wheels 1 have a similar orientation to the discs 501, although the angle may differ.

[0062] Because of these particular orientations, the forces exerted on wheels 1 due to ground resistance and friction are high. They are greater than those that would be exerted on an identical wheel 1 whose axis of rotation XX was substantially perpendicular to the direction of travel and / or horizontal.

[0063] Stresses tend to be concentrated at the hub and the connection to the axle. The improvements introduced by the invention are therefore of particular interest to agricultural implements with a similar configuration.

[0064] A tool according to the invention offers the necessary mechanical strength for field work while being made using two flanges manufactured with less material than existing two-flange wheel bodies. By differentiating the functions of each flange, they have different structures. Raw material can be saved by omitting the arm and central section of the second flange. The wheel body is thus streamlined and lighter. Transportation and manufacturing costs are reduced.

[0065] The manufacture of at least one of the two flanges, the annular one hollowed out in the center, is simplified and faster. Manufacturing costs are further reduced.

[0066] In existing two-flange wheels, ensuring proper interaction between three elements is complex. For example, the bearing must be sized and supported not only with respect to the first flange but also with respect to the second flange. In the invention, the bearing does not interact directly with the second flange. For example, the bearing housed in the hub can be removed from its housing for replacement during maintenance without having to disassemble the two flanges, regardless of the condition of the second flange.

[0067] Manufacturing tolerances can be increased.

[0068] The invention is not limited to the examples of tools described above, only by way of example, but encompasses all the variants that a person skilled in the art may consider within the scope of the following claims.

Claims

1. Field work tool (1) of the type comprising a first flange (7) and a second flange (9) which are mounted one on top of the other to form a wheel body (3), the first flange (7) having a central part (71), a peripheral part (73) of generally annular shape, and at least one arm (75) connecting the central part (71) and the peripheral part (73) to each other, the second flange (9) is homologous to the peripheral part (73) of the first flange (7), in the mounted state, the wheel body (3) has a rim (121) formed jointly by the peripheral part (73) of the first flange (7) and the second flange (9) and a hub formed by the central part (71) of the first flange (7).

2. Tool (1) according to claim 1, in which the first flange (7) and the second flange (9) are made of two different materials.

3. Tool (1) according to any one of the preceding claims, wherein the second flange (9) is made of metal.

4. Tool (1) according to any one of claims 1 and 2, wherein the first flange (7) is made of plastic material and the second flange (9) is made of plastic material.

5. Tool (1) according to any one of the preceding claims, wherein the second flange (9) is formed of at least two pieces in the general shape of ring sections.

6. Tool (1) according to any one of the preceding claims, in which each of the first flange (7) and the second flange (9) supports a tire (5) threaded onto the rim (121).

7. Tool (1) according to any one of the preceding claims, in which, when mounted one on top of the other, the hub of the first flange (7) protrudes at least partially into an internal space defined by the annular shape of the second flange (9).

8. Tool (1) according to any one of the preceding claims, wherein the peripheral part (73) of the first flange (7) and the second flange (9) each have an external surface (93; 113) whose diameter in the vicinity of the interface between the first flange (7) and the second flange (9) in the mounted state is different from the diameter on the side opposite the interface between the first flange (7) and the second flange (9), so that the rim (121) has a seat (201) of generally concave or convex shape suitable for receiving a tire (5).

9. Tool (1) according to any one of the preceding claims, wherein the peripheral part (73) of the first flange (7) and the second flange (9) are mutually formed so that their assembly defines a groove (161) extending substantially over the circumference of the wheel body (3) at the interface of the peripheral part (73) of the first flange (7) and the second flange (9), the groove (161) being suitable for housing a bead (53) of a tire (5).

10. Tool (1) according to any one of the preceding claims, wherein the first flange (7) is one piece and the second flange (9) is one piece.