Steel sheet stake for viticulture or fruit growing

Abstract

The invention relates to a steel sheet stake (1), particularly for use in viticulture, fruit growing, or fencing, consisting of a hollow profile. The stake has, at a lower end (101) intended to be planted in the ground, a foot extending into a main body (103) to an upper end opposite the lower end (101). According to the invention, a constriction (13) is provided in the foot of the stake such that the cross-section of the lower end (101) has a star shape, the area inscribed in the cross-section of the star at the lower end (101) of the stake being smaller than the area inscribed in the cross-section of the profile of the main body (103). (See Figure 3 for abbreviations.)

Description

Title of the invention: Steel sheet stake for viticulture or fruit growing. Technical field

[0001] The invention relates to a steel sheet stake, particularly for viticulture, fruit growing, or fencing, consisting of a hollow profile. The stake has, at a lower end intended to be planted in the ground, a foot extending into a main body up to an upper end opposite the lower end. The invention also relates to a method for manufacturing a steel sheet stake according to the invention, as well as a shrink press for implementing the method. Prior art

[0002] Steel sheet stakes are commonly used in viticulture and fruit growing. They often consist of a U-shaped profile with a central wall flanked by two lateral walls that are oblique to the central wall. For stability, the edges of the U's wings are often reinforced with rolled edges whose corners curve towards the center of the stake, forming a return. To ensure good stability for the trellising, it is recommended to plant the stakes in the ground to a depth of at least 60 cm when they are less than 2 m long, or to about 1 / 3 of their height for taller stakes. The stakes are driven into the ground by applying force to the top of the stake. However, it can sometimes be difficult to plant a stake, particularly in hard or stony soils.The soil penetrates the profile, compacts as the post is driven into the ground, and eventually forms a footing that resists the post's penetration. The post may then become deformed and not be vertical and aligned within the row of posts. In such a case, agricultural machinery risks deforming or even breaking the misaligned posts. Steel sheet posts are also used for fence installation and encounter the same problems.

[0003] The objective of the invention is therefore to improve the resistance of the stakes to penetration into the soil to facilitate planting. Another objective is to develop a rapid and economical manufacturing process and the corresponding implementation device. Description of the invention

[0004] According to the invention, a constriction is provided in the foot of the stake so that the cross-section of the lower end has a star shape, the surface inscribed in the cross-section of the star at the lower end of the stake being less than the surface inscribed in the cross-section of the profile of the main body. The cross-section of the stake at the lower end is preferably substantially closed, so that soil cannot enter the profile through the lower end when driving the stake into the ground.

[0005] For better penetration of the stake into the ground, it is preferable that the constriction consist of a point of constant cross-section and a transition zone whose cross-section decreases continuously from the cross-section of the profile of the main body of the stake to the cross-section of the point.

[0006] In particular, the invention is particularly well suited to a stake whose profile in the main body has an open or closed polygonal cross-section having N angles and N or Nl walls, the cross-section of the lower end of the stake having the shape of an N-pointed star, where N is equal to or greater than three. The ends of the points of the star are formed by the angles located between successive walls, angles which have been flattened, and, when the profile is open and has Nl walls, by the edges of the walls adjacent to the opening of the profile. Alternatively or complementarily, Nl hollows between the branches of the star are each formed by one of the walls deformed towards the center of the stake so as to be opposite or to touch the adjacent wall for nearly half of their respective width, and the last hollow being preferably formed by the last wall deformed towards the center of the stake when the profile has N walls, or by a part of the walls adjacent to the opening.

[0007] For reasons of stability, it is common practice in open-profile stakes for the stake walls adjacent to the longitudinal opening to have a return. In particular, the stake may consist of an open polygonal profile, preferably U-shaped, with a central wall and two lateral walls oblique to the central wall. The edges of the walls adjacent to the opening continue as rolled edges whose free edges lie inside the stake. The rolled edges, as well as the angles between the rolled edges and the walls to which they are attached, are deformed in the constriction.

[0008] In this case, the angles located between the rolled edges and the walls to which they are attached are flattened at the lower end of the stake, and in particular in the point when the stake is equipped with such a point, and each deformed rolled edge at the lower end of the stake is opposite or touches the wall to which it is attached, forming with the corresponding wall a branch of the star.

[0009] One or more tabs can be fixed to the stake or made by cutting with a die by forming a punched hole, and by forming and folding the tabs thus obtained.

[0010] The invention also relates to a method for manufacturing the shrinkage according to the invention in a rapid and economical manner. This method comprises the following steps: - cutting on the fly in a cutting tool of a profile to continuously obtain stakes of the desired length; - introduction of the free end of the profile, or of the end of a stake opposite to the last cut end, into a shrink press to deform the lower end by forming the shrink, so that the cross-section of the lower end has a star shape, the inscribed area in the cross-section of the lower end of the stake being less than the inscribed area in the cross-section of the main body profile. - The shrink press is mobile in the direction of movement of the profile in the cutting tool, so that, during the formation of the shrink, the stake or profile moves with the shrink press in the same direction as the profile in the cutting tool, preferably at the same speed. - The shrink press is opened after the shrink is formed, and the stake continues its journey in the direction of the profile's advance in the cutting tool, while the shrink press returns to its initial position by moving in the opposite direction to the direction of the profile's movement in the cutting tool. - The formation of the constriction is carried out on the free end of the profile at the same time as the cutting of the stake, or on the end of the last stake cut opposite the end cut last.

[0011] Thanks to this operating method, it is possible to manufacture the shrinkage at the same rate as the post cutting, either simultaneously or immediately after the cut. There is no need to transfer the posts to another line, nor to slow down the cutting tool's operating speed. When the cutting tool requires the insertion of a core into the profile to prevent deformation during cutting, the shrinkage is manufactured after the cut and the core removal. These methods have the advantage of not damaging certain pretreatments, such as galvanizing. However, there are cutting methods that do not require the insertion of a core, such as cutting with an abrasive disc circular saw. In this case, it is possible to perform the shrinkage simultaneously with the cut, or even before.These methods will be chosen for steel sheets that are not likely to be damaged by the heat applied during cutting, such as untreated steel sheets.

[0012] The foot of the stake, or the part of the profile located in the shrink press, can be deformed to form a point of constant cross-section ending at the lower end of the stake or at the end of the profile, and a transition zone whose cross-section decreases continuously from the cross-section of the profile of the main body of the stake to the cross-section of the point.

[0013] The method is particularly well suited to stakes whose profile, in the main body, has an open or closed polygonal cross-section having N angles and N or Nl walls. In this case, the base of the stake, or the part of the profile located in the shrink press, can be deformed by the shrink press in such a way that the cross-section of the lower end of the stake at the end of the deformation has the shape of a star. The angles between successive walls are, at the lower end of the stake, flattened, each forming the end of a branch of the star, and when the profile is opened and has Nl walls, the walls adjacent to the opening are deformed in the shrinking press so that their edge adjacent to the opening forms the end of a branch of the star. Alternatively or complementarily, each of the walls is deformed towards the center of the stake so as to be opposite or to touch the adjacent wall for almost half of its width, each forming, at the lower end of the stake, a hollow between the points of the star.

[0014] The method can be applied to an open polygonal profile, preferably U-shaped, with a central wall and two lateral walls oblique to the central wall, the edges of the walls adjacent to the opening continuing as rolled edges whose free edges lie inside the profile. In this case, the rolled edges, as well as the angles between a rolled edge and the wall to which it is attached, are deformed in the shrink press. It is preferable to flatten the angles at the lower end of the stake between a rolled edge and the wall to which it is attached, especially at the point when the stake has one. Each rolled edge is preferably deformed at the lower end of the stake so that it is flush with or touches the wall to which it is attached, forming a star-shaped arm with the corresponding side wall.

[0015] The process of the invention is preferably integrated into a complete line for manufacturing steel sheet stakes. For this purpose, the free-cutting step is preceded by one or more of the following steps carried out in a continuous process: - unwinding a steel strip from a coil received in a reel; - passing the steel strip through a planer to flatten it; - passing the steel strip through a press to cut tabs from the steel strip which are bent and shaped to form tabs; - passing the steel strip through a profiling machine to subject it to profiling until a profile is obtained, preferably a profile with rolled edges when the profile is open; The steel strip is then fed in a single movement to the cutting tool. Thus, the entire manufacturing line operates at the same speed. The steel strip, unwound from the coil, advances at a continuous speed to the cutting tool, or even up to the shrink press if the cutting is concurrent with, or even subsequent to, the formation of the shrinkage.

[0016] The profile can first be cut in the cutting tool, then the resulting stake can be accelerated to create a gap between the upper end of the last stake cut (the one leaving the cutting tool) and the lower end of the next stake to be cut. In this case, the accelerated stake is then fed into the shrink press.

[0017] The invention also relates to a press for implementing the method of the invention. The press is composed of movable plates, each carrying a punch. Furthermore, the shrink press is movable in the direction of the longitudinal extension of the stakes and is equipped with means for moving it in one direction during the pressing operation, and in the other direction when the pressing operation is complete.

[0018] The press of the invention is preferably integrated into a stake manufacturing line according to the invention. The manufacturing line preferably comprises the following tools: - a reel on which a spool can be mounted, around which a steel strip is wound; - a planer through which the steel strip is passed to flatten it; - a press through which the steel strip passes to cut and form tabs; - a profiling machine through which the steel strip passes to form a profile, preferably with rolled edges when the profile is open; - the cutting tool through which the profile passes; and - the shrink press of the invention; the different tools are designed to work together in a synchronized manner to allow for a continuous process. Brief description of the figures

[0019] The invention is described in more detail below with the help of the figures which show: [Fig.1] a longitudinal cross-sectional view of a stake according to the invention according to section II of [Fig.4]; [Fig.2] an enlarged view of the upper end of the stake of [Fig.1]; [Fig.3] a perspective view of the tip of the stake of [Fig.1]; [Fig.4] a view from below of the tip of the stake of [Fig.1]; [Fig.5] a schematic view of the shrink press (a) in open position with a point to be pointed, (b) in closed position around the pointed point, (c) in open position with the pointed point ready to come out. Detailed description of the invention

[0020] The invention applies to all stakes made of a hollow profile, whether the profile has a round or polygonal cross-section, and whether it is closed or open. By open profile, we mean means a profile whose cross-section remains constant over the entire length of the profile, but which has a longitudinal slot along its entire length so that the inside of the profile is in contact with the outside, other than through the ends.

[0021] The invention is described by way of a stake made of a U-shaped profile. This is therefore a polygonal section with four sides (N = 4), open on one of the sides. In the example presented here, the fourth side is not entirely absent since the longitudinal opening of the profile is bordered by two rolled edges (114, 115). The invention can, however, be easily generalized to profiles in the shape of a circle, or a triangle (N = 3), a pentagon (N = 5), a hexagon (N = 6) or an octagon (N = 8), for example, or to polygonal profiles with N1 sides when the longitudinal opening extends over the entire width of one side.

[0022] The figures show a stake (1) made of galvanized sheet steel for viticulture or fruit growing. These stakes have a longitudinal extension (in the vertical direction) and a cross-section (perpendicular to the longitudinal extension) that is substantially U-shaped. The stake has, on the foot side, a lower end (101) intended to be planted in the ground and, on the head side, an upper end (102).

[0023] The stake is made from a steel strip formed by profiling to obtain a U-shaped profile. The U-shaped profile comprises a central wall (111) which continues on each side as a lateral wall (112, 113), the central wall forming the central arm of the U-shaped profile and the lateral walls forming the two flanges of the U-shaped profile. The lateral walls (112, 113) are oriented obliquely with respect to the central wall (111). In the case presented here, they form substantially a right angle with the central wall (111). The two lateral walls (112, 113) are preferably symmetrical with respect to a median plane passing through the central wall (111). The edges of the lateral walls opposite the central wall preferably continue as rolled edges (114, 115) directed towards the interior of the stake. These rolled edges form returns leaving an opening all along the U-shaped profile.These feedback mechanisms, on the one hand, prevent a user from being injured and, on the other hand, increase the resistance of the stake and limit its rotation.

[0024] The stake includes tabs (12) located on the outer face of the side walls (112, 113). They are formed by die cutting, creating a punched hole, and then by forming and bending the tabs thus cut from the steel sheet. Each tab has a base extending obliquely outwards from the side wall and continues as a lug extending substantially parallel to the side wall on which the tab is formed. These tabs (12) hold the wires extending between the stakes. On the same stake, there may be single tabs open towards the upper end of the stake and / or double tabs. One of the tabs is open towards the upper end of the stake and the other towards the lower end, their openings facing each other. The tabs are preferably designed so that they cannot be driven in.

[0025] The base of the stake, on the side of the lower end (101) intended to be planted in the ground, has a taper (13) to facilitate planting. The taper is located in line with the main body (103) of the stake. In the example shown here, the taper consists of a point (131) with a substantially constant cross-section, and a transition zone (132) located between the point (131) and the main body (103) and whose cross-section decreases continuously from the cross-section of the main body (103) of the stake to the cross-section of the point (131).

[0026] In the embodiment shown here, the point has an X-shaped cross-section. This shape prevents soil from entering the stake during planting and also provides the end of the stake (1) with great strength and mechanical resistance. Furthermore, it allows stones to be moved aside, or, if necessary, to be bypassed around large stones.This shape is obtained by pushing the central wall (111) and the lateral walls (112, 113) towards the center of the stake into the transition zone (132), progressively between the junction between the main body (103) and the tip, and pinching just as progressively the angles (116, 117) located between the central wall (111) and each lateral wall (112, 113) and the angles (118, 119) located between the lateral walls (112, 113) and the corresponding rolled edges (114, 115), so that at the end of the transition zone and in the tip, the inner faces of the walls (111, 112, 113) and the rolled edges (114, 115) are opposite each other in pairs, or even in contact in pairs, forming an X.Thus, a first section of the central wall (111) is aligned with a first section of the first lateral wall (112), and another section of the central wall (111) is aligned with a first section of the second lateral wall (113), while other sections of the lateral walls (112, 113) are aligned with the walls forming the rolled edges (114, 115) in the main body (103) of the stake. In the example shown here, the transition zone (132) continues from the point (131) to the lower end (101) to facilitate planting. However, it is possible to omit the point, so that the constriction (13) in this case consists only of the transition section (132) ending at the lower end (101) of the stake.

[0027] The surface inscribed in the cross-section of the lower end (101) in the shape of X is less than the surface inscribed in the cross-section of the U-shaped profile of the main body of the stake, that is to say substantially the rectangle defined by the three walls of the U-shaped profile. The walls being brought together in pairs, they are more resistant.

[0028] A stake according to the invention can therefore be planted so that its base with the constriction (13) and a substantial part of its main body (103) are in the ground. The point (131), when it has one, and the transition zone (132) facilitate driving the stake into the ground.

[0029] The invention also relates to a method for economically manufacturing such a stake. In the method according to the invention, the step of forming the shrinkage is integrated into the manufacturing process of the stake.

[0030] The manufacture of a stake is preferably carried out using a continuous process in which all the manufacturing steps are performed on the fly on the continuously moving metal strip. The process takes place as follows: - a steel strip, galvanized or not, is unwound from a reel placed on a reel; - the strip taken from the reel first passes through a planer to finish unwinding and flattening it as it comes off the reel; - it is gripped by a clamp which moves it continuously along the production line; - the strip passes through a first press to cut and form the tabs on the fly; - it is then subjected to profiling by passing through a succession of profiling heads until the desired shape is obtained, here a U-shaped profile with rolled edges; - the resulting profile is passed through a cutting tool to cut it from the stakes to the desired dimensions. This results in a traditional stake.

[0031] By "on the fly," it is meant that the step in question takes place on the moving strip so that it is not necessary to interrupt the unwinding of the steel strip. To achieve this, the presses for preparing the tabs and the cutting press move in a continuous back-and-forth motion, in the direction of travel and at the same speed as the steel strip while performing their task, then in the opposite direction to return to their initial position and restart the cycle at a point further up the strip. The tools are, for example, mounted on rails parallel to the direction of travel of the steel strip. Their movements are synchronized with the advance of the strip to ensure smooth unwinding of the process.

[0032] The invention consists of adding an additional step after the cutting.

[0033] Usually, post-cutting processing takes place in a separate station independent of the continuous stake production line. If a stake needs to be deformed, a die is first placed inside the stake to be deformed, the stake with the die in place is then passed through a press, and the die is removed. Due to The use of a die that is inserted and then removed in the opposite direction makes it impossible to integrate such a manufacturing step into the continuous production line.

[0034] The invention provides for deforming the base of the stake located on the lower end side (101) of the stake without using an internal die. For this purpose, a shrinking press (2) is placed following the cutting tool. This shrinking press is equipped with four plates (211, 212, 213, 214) movable in directions perpendicular to the longitudinal extension of the stake and directed towards the center of the stake. The stake (1) of the exemplary embodiment having three walls (111, 112, 113) forming two right angles, the plates (211, 212, 213, 214) move in two perpendicular directions (horizontal and vertical in the case of the shrinking press shown in [Fig. 5]). Each plate (211, 212, 213, 214) has a punch (221, 222, 223, 224) which together give shape to the shrinkage (13). Each punch (221, 222, 223, 224) has a V-shaped working surface.The movement of the plates (211, 212, 213, 214) is such that the tips of the V-shaped profiles move towards the center of the stake. The angle of the V at the end of the transition zone and the tip is close to the angle between the two diagonals of the stake body (1) passing through two opposite angles (116-119, 117-118). In the example shown in the figures, the angle is approximately 70° on the side of the central wall (111) and the open end of the U-shaped profile, and approximately 110° on the side of the lateral walls (112, 113), because the lateral walls are wider than the central wall (111). The angle of the V-shaped profiles widens as one moves away from the tip (131) and towards the main body (103) of the stake. Thus, at the junction between the transition zone (132) and the main body (103), the angles of the V are flat (180°).As the angles of the V open, the point of the V moves away from the center of the stake and towards the initial plane of the wall, so that at the junction between the main body (103) and the transition zone (132), the point of the V is at the level of the initial plane of the wall in question. At the end of the transition zone (132), near the lower end (101) of the stake, and in the point (131), the points of the V are positioned on their respective plates so as to bring the centers of the walls (111, 112, 113) as close as possible to each other, so that they touch or nearly touch. In this example, the punches (222, 223) deforming the side walls (112, 113) are identical.The punch (224) on the open face of the stake must deform the walls of the rolled edges (114, 115) by bringing them closer and closer to the corresponding lateral walls (112, 113), which are themselves increasingly deformed as one approaches the point (131). At the junction between the transition zone and the point, and along the entire length of the point, the angles (116, 117) located between the successive walls (112 / 111, 111 / 113) and the angles (118, 119) located between the lateral walls and the corresponding rolled edges (112 / 114, 113 / 115) are practically numb, and the inner faces of the . corresponding parts of adjacent walls (114 / 112, 112 / 111, 111 / 113, 113 / 115) touch or almost touch.

[0035] The shrink press (20) is opened by spreading the four plates (211, 212, 213, 214) apart to allow sufficient space for the passage of the post foot located at the lower end (101) of the post. A movable stop prevents the post foot from moving through the press. The press is then closed by synchronously bringing the plates (211, 212, 213, 214) together towards the center of the post. The punches deform the U-shaped profile, starting from the lower end (101). At the end of the stroke, the post foot is deformed, forming the X-shaped shrinkage (13). The plates are spread apart again, the movable stop is moved away, and the post leaves the press, continuing its forward movement.

[0036] The plates have a set of beveled surfaces such that the movement towards the center of the peg of the upper plate (214) causes the corresponding movement of the lateral plates (212, 213) which in turn causes the corresponding movement of the lower plate (211). The movement of the four plates is synchronous.

[0037] The shrink press (2) is itself mounted on rails so that it can move in a direction parallel to the longitudinal extension of the post, and more generally to the direction of movement of the sheet metal in the post manufacturing line. Thus, the shrink (13) is produced at the same time as the post advances during cutting, or directly after cutting. It is possible to perform the shrinking at the same time as the post cutting operation. However, it may be preferable, in some cases, to accelerate the post as it exits the cutting operation towards the shrink press in order to create a gap between the upper end (102) of the freshly cut post and the lower end (101) of the next post to be cut. The accelerated post enters the press where its accelerated movement is slowed by the press stop, which advances simultaneously with the lower end (101) of the next post to be cut.The distance between the ends of the two successive stakes is maintained throughout the operation. The finished stake continues its journey and exits the shrink press from the opposite side to the side from which it entered, thus making room for the new stake.

[0038] The tapered lower end of the stake facilitates its insertion into difficult terrain. It closes the bottom of the stake and prevents soil from penetrating it during planting. By avoiding this soil penetration, the stake's resistance in the soil (sole effect) is reduced. Its pointed design increases its penetration coefficient and helps to dislodge stones. The soil then compacts around the outer edge of the stake, which in turn increases stability in the ground. This is very important because it helps maintain the verticality of the trellis for the passage of machinery (pre-pruner, harvester, soil cultivator, etc.). The tapered end, preferably with a point, completes the stake in its planting function.

[0039] The on-the-fly process according to the invention, carried out following the continuous manufacturing process for the stakes, allows for a very significant time saving compared to a separate process. The shrink manufacturing step does not lead to a significant increase in manufacturing costs.

[0040] The process of the invention can be carried out on sheet steel that has previously undergone a surface treatment, such as galvanizing. It can also be applied to sheet steel that has not been surface treated, so that the finished stake can subsequently be subjected to such a surface treatment, such as galvanizing or powder coating.

[0041] The method has been described using the example of a U-shaped stake with rolled edges (114, 115). It could also be used for simple U-shaped stakes. In this case, two arms of the X are formed by bringing together a portion of the central wall and a portion of the adjacent side wall, and the other two arms are formed by the remaining portions of the side walls. Consequently, two arms have double the wall thickness, while the other two arms have only a single wall thickness. Similarly, it is not essential that the walls (111, 112, 113) be flat and perpendicular to each other. They could be profiled and more or less inclined with respect to the central wall (111). It is not necessary that they be symmetrical with respect to a median plane of the central wall.

[0042] As mentioned previously, it would be possible to use the method of the invention for a triangular profile, in which case the lower end of the stake has a three-pointed star shape rather than an X shape. More generally, the method can be used for a multi-faceted stake, particularly a hexagonal or octagonal stake, by forming star-shaped recesses with as many points as there are faces on the stake. When the profile is circular, the choice of the star shape is left to the manufacturer's discretion. The three- or four-pointed star solution is probably the simplest.

[0043] The invention could be applied to stakes made of a metallic material other than steel. In particular, it could be applied to aluminium stakes. List of references

[0044] 1 Stake 101 Lower end 102 Upper end 103 Main body of the stake 111 Central wall 112 first side wall 113 2nd side wall 114 1st rolled edge 115 2nd rolled edge 116 Angle located between the central wall and the first side wall 117 Angle located between the central wall and the 2nd side wall 118 Angle located between the first side wall and the first rolled edge 119 Angle located between the 2nd side wall and the 2nd rolled edge 12 Tongue and Grommets 13 Restricted 131 Pointe 131 Transition Zone 2 Shrink press 211 Mobile plate 212 Movable plate 213 Movable plate 214 Movable plate 221 Punch 222 Punch 223 Punch 224 Punch

Claims

1. Demands Sheet metal stake, preferably made of steel sheet, particularly for viticulture, fruit growing or fencing, consisting of a hollow profile, the stake having, at a lower end (101) intended to be planted in the ground, a foot continuing as a main body (103) to an upper end (102) opposite the lower end (101), the foot of the stake being provided with a taper (13) so that the cross-section of the lower end (101) has a star shape, the surface inscribed in the cross-section of the star at the lower end (101) of the stake being less than the surface inscribed in the cross-section of the profile of the main body (103), characterized in that the stake is made of an open polygonal profile having N angles (116, 117, 118, 119) and N1 walls (111, 112, 113) where two successive walls (112 / 111, 111 / 113) are connected by an angle (116, 117),The cross-section of the lower end (101) of the stake has the shape of an N-pointed star; the ends of the points of the star are formed by the angles (116, 117) located between the successive walls (112 / 111, 111 / 113) and which are flattened, and by the edges (118, 119) adjacent to the opening of the profile of the walls (112, 113) adjacent to said opening of the profile, and / or, The hollows between the points of the star are each formed by one of the walls (111, 112, 113) deformed towards the center of the stake so as to be opposite or touching a part of the adjacent wall, and in that the edges adjacent to the opening of the profile of the walls (112, 113) adjacent to said opening of the profile continue as rolled edges (114, 115) whose free edges are located inside the stake, the rolled edges as well as the angles (118, 119) located between the rolled edges and the walls (112, 113) to which they are attached being deformed in the constriction so that the angles (118, 119) located between the rolled edges (114, 115) and the walls (112, 113) to which they are attached are flattened at the lower end of the stake, each forming an end of one branch of the star, and each rolled edge (114, 115) deformed at the lower end of the stake being opposite or touching the wall (112, 113) to which it is attached by forming with a part of the corresponding wall a branch of the star.

2. Stake according to the preceding claim, characterized in that the stake is made up of an open U-shaped polygonal profile with a central wall (111) and two lateral walls (112, 113) oblique to the central wall (111), the edges adjacent to the opening of the profile of the walls (112, 113) adjacent to said opening of the profile continuing into rolled edges (114, 115) whose free edges are located inside the stake, the rolled edges as well as the angles (118, 119) located between the rolled edges and the walls to which they are attached being deformed in the constriction.

3. Stake according to any one of the preceding claims, characterized in that the constriction (13) consists of a point (131) of constant cross-section ending at the lower end of the stake or at the end of the profile, and a transition zone (132) whose cross-section decreases continuously from the cross-section of the profile of the main body (103) of the stake to the cross-section of the point (131).

4. Stake according to any one of the preceding claims, characterized in that one or more tabs (12) are fixed to the stake, or made by cutting with a die by forming a punched hole, and by forming and folding tabs thus obtained.

5. A method for manufacturing a sheet metal post, preferably made of steel sheet, particularly for viticulture, fruit growing, or fencing according to any one of the preceding claims, said method comprising the following steps: - cutting a profile in a cutting tool to continuously obtain posts of the desired length, the profile being a polygonal profile open with N angles and N1 walls; characterized by the additional step - introducing the free end of the profile, or the lower end (101) of a post opposite the upper end (102) cut last, into a shrink press (2) to deform the lower end (101) by forming the shrink (13), so that the cross-section of the lower end (101) has an N-pointed star shape, the inscribed area in the cross-section of the lower end (101) of the post being less than the surface inscribed in the cross-section of the main body profile, the angles (116, 117) situated between the successive walls (111 / 112, 111 / 113) being, at the lower end (101) of the stake, flattened, each forming the end of a point of the star, and the walls (112, 113) adjacent to the opening being deformed in the shrinking press (2) such that their edge (118, 119) adjacent to the opening forms the end of a point of the star, and / or each of the walls (111, 112, 113) is deformed towards the center of the stake so as to be opposite or to touch a part of the adjacent wall (111 / 112, 111 / 113), each forming, at the lower end (101) of the stake, a hollow between the points of the star, - the press of the shrinkage (2) being movable in the direction of movement of the profile in the cutting tool, so that, during the formation of the shrinkage,The stake (1) or profile moves with the shrink press in the same direction as the profile in the cutting tool, preferably at the same speed, - the shrink press (2) being open after the shrinkage has formed, and the stake (1) continuing its course in the direction of advancement of the profile in the cutting tool, while the shrink press returns to its initial position by moving in the opposite direction to the direction of movement of the profile in the cutting tool, - the formation of the constriction being carried out on the free end of the profile at the same time as the cutting of the stake, or on the lower end (101) of the last stake cut opposite the end cut last, and in that the edges adjacent to the opening of the profile of the walls (112, 113) adjacent to said opening of the profile continue with rolled edges (114, 115) whose free edges are located inside the stake, - the rolled edges (114, 115) as well as the angles (118, 119) located between a rolled edge (114, 115) and the wall (112, 113) to which it is attached being deformed in the shrinking press (2), - the angles (118, 119) located between a rolled edge (114, 115) and the wall (112, 113) to which it is attached being flattened at the lower end (101) of the stake, and each rolled edge (114, 115) being deformed at the lower end of the stake to be opposite or touch the wall (112, 113) to which it is attached, forming with a part of the corresponding wall a branch of the star.

6. A method according to claim 5, characterized in that the foot of the stake, or the part of the profile located in the shrinking press, is deformed to form a point (131) of constant cross-section ending at the lower end (101) of the stake or at the end of the profile, and a transition zone (132) whose cross-section decreases continuously from the cross-section of the profile of the main body (103) of the stake to the cross-section of the point (131).

7. A method according to any one of claims 5 or 6, characterized in that the free-cutting step is preceded by one or more of the following steps carried out in a continuous process: - unwinding a steel strip from a coil received in a reel; - passing the steel strip through a planer to flatten it; - passing the steel strip through a press to cut tabs in the steel strip which are bent and formed to form tabs (12); - passing the steel strip through a profiling machine to subject it to profiling until a profile (111, 112, 113) is obtained, preferably with rolled edges (114, 115) when the profile is open; the steel strip then being brought in the same movement to the cutting tool.

8. A method according to any one of claims 5 to 7, characterized in that the profile is first cut in the cutting tool, then the resulting stake is accelerated to create a space between the upper end of the last stake cut and the lower end of the next stake to be cut, and in that the lower end (101) of the stake thus accelerated is introduced into the shrinking press (2).

9. A shrinking press for implementing the method according to any one of claims 5 to 8, characterized in that it is composed of movable plates (211, 212, 213, 214), each carrying a punch (221, 222, 223, 224), and in that the shrinking press (2) is movable in a direction of movement corresponding to the direction of the longitudinal extension of the pegs, and in that it is equipped with means for moving it in a direction of movement during the pressing operation, and in

10. the other direction of movement when the press operation is complete, the plates (211, 212, 213, 214) being movable in directions perpendicular to the extension of movement of the shrink press (2), and in that The punch (224) intended for the open face of the stake is designed to deform the walls of the rolled edges (114, 115) by bringing them closer and closer to the corresponding lateral walls. A production line for sheet metal stakes, preferably made of steel sheet, particularly for viticulture or fruit growing according to any one of claims 1 to 4, comprising the following tools: - a reel on which a spool can be mounted, around which a steel strip is wound; - a planer through which the steel strip can be passed to flatten it; - a press through which the steel strip can pass to cut and form tabs; - a profiling machine through which the steel strip passes to form a profile, preferably with rolled edges when the profile is open; - a cutting tool through which the profile can pass; and - the shrink press (2) of claim 9; the different tools are designed to work together in a synchronized manner to allow for a continuous process.

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