EP0110925B1 - Tool for driving in and guiding pegs for fixing stakes - Google Patents

Abstract

The tool comprises a rigid elongated body having a lower portion of which the cross-section corresponds substantially to that of the central sleeve of the peg, an upper portion intended to cooperate with a member applying a driving-in force, such as a ram, and a central portion (2) having: an upper part (20) of larger cross-section and capped by a bell-shaped piece (4) of which the upper surface (42) is traversed by the elongated body and forms a striking surface and a lower part (21) of reduced cross-section surrounded by a flat piece (5) of which the lower surface (52) forms a bearing surface and of which the upper surface is connected to the base of said bell (4), said flat bearing part (5) being provided with a central recess (51).

Description

The invention relates to the anchoring, in the ground, of poles or stakes, by means of a dowel having a rigid part, advantageously composed of metal plates shaped into fins, said rigid part forming a sheath intended to receive, once the dowel is sunk into the ground, the base of the post or stake.

• »Cheville destinée à la fixation dans le sol de poteaux ou piquets et dispositif servant à l'enfoncement de cette cheville«,

d'utiliser un outil comportant un corps allongé rigide et un manchon formant bélier, monté coulissant sur la partie supérieure dudit corps allongé pour venir coopérer avec une surface transversale supérieure plane d'une rondelle centrale que comporte ledit corps allongé, tandis qu'une surface transversale inférieure de ladite rondelle, située à une distance de l'extrémité inférieure dudit corps allongé légèrement supérieure à la hauteur de la cheville, prend appui par sa partie périphérique sur ladite pièce rigide et est munie d'un évidement central. Avec un tel outil, l'opération d'enfoncement d'une cheville s'effectue en introduisant, dans le fourreau de celle-ci, alors qu'elle est simplement posée sur le sol en position verticale, la partie inférieure du corps de l'outil, qui joue ainsi le rôle d'un faux piquet, sur une longueur légèrement supérieure à la hauteur de la cheville, de façon que l'extrémité inférieure du corps de l'outil pénètre légèrement dans le sol. On fait alors coulisser le bélier, muni à cet effet de poignées de manœuvre, sur la partie supérieure du corps de l'outil, de façon à imprimer des chocs répétés sur ladite surface transversale supérieure ou surface de frappe. La surface transversale inférieur ou surface d'appui transmet les chocs au bord supérieur des ailettes de la cheville et enfonce celle-ci dans le sol suivant l'axe général de l'outil avec guidage par la partie supérieure du corps de l'outil. Lorsqu'on a enfoncé la cheville complètement dans le sol, on retire le faux piquet et on introduit un piquet dans le fourreau de la cheville, jusqu'à ce que sa base pénètre légèrement dans le sol, à la profondeur atteintre par l'extrémité inférieure du faux piquet. Au cours de l'enfoncement de la cheville, l'évidement central de la surface d'appui de l'outil préserve le fourreau de la cheville d'un sertissage qui empêcherait la mise en place ultérieure du piquet.To drive such pegs into the ground, the first certificate of addition to the French patent No. 7811279, proposed on April 10, 1979 under No. 7909679, was proposed by the Applicant and having as its title:

• "Anchor intended for fixing posts or pegs in the ground and device used to drive this anchor",

using a tool comprising a rigid elongated body and a ram-forming sleeve, slidably mounted on the upper part of said elongated body to come to cooperate with a planar upper transverse surface of a central washer that comprises said elongated body, while a surface lower transverse of said washer, located at a distance from the lower end of said elongated body slightly greater than the height of the ankle, bears by its peripheral part on said rigid part and is provided with a central recess. With such a tool, the operation of driving in an ankle is carried out by introducing, into the sheath thereof, while it is simply placed on the ground in a vertical position, the lower part of the body of the tool, which thus plays the role of a false stake, over a length slightly greater than the height of the dowel, so that the lower end of the body of the tool penetrates slightly into the ground. The ram is then made to slide, provided for this purpose with operating handles, on the upper part of the body of the tool, so as to impart repeated shocks to said upper transverse surface or striking surface. The lower transverse surface or bearing surface transmits shocks to the upper edge of the ankle fins and drives the latter into the ground along the general axis of the tool with guidance from the upper part of the tool body. When the ankle has been fully inserted into the ground, the false stake is removed and a stake is inserted into the ankle sheath, until its base penetrates slightly into the ground, to the depth reached by the end lower of the false stake. During the insertion of the dowel, the central recess of the support surface of the tool preserves the sheath of the dowel from crimping which would prevent the subsequent placement of the stake.

Ultimately, this tool allows you to push the dowel well into the ground, without deforming it and without letting the earth penetrate its sheath.

However, it presents a difficulty of realization due to the fact that the exercise of violent shocks involves a significant risk of breakage, in particular at the level of the central protuberance of the body or of the junctions of the handles with the ram.

The invention relates to a tool of the aforementioned type, which offers a particularly high impact resistance and also allows easy replacement of the most fragile elements in the event of wear or breakage.

According to the main characteristic of the invention, the central part of said elongated body comprises: an upper portion of larger section capped by a bell-shaped part provided with a central passage for the upper part of the elongated body and whose upper surface forms said striking surface; and a lower portion whose section has a dimension equal to the circle inscribed in the horizontal section of the ankle sleeve, said lower portion being surrounded by a flat piece whose lower surface constitutes said bearing surface and whose upper surface is connected to the base of said bell.

According to another characteristic of the invention, the lower part or pin of said elongated body comprises a lower end portion whose section has a dimension substantially equal to that of the ankle sheath and having a pointed end and an upper portion connected to said lower portion of the central part and of reduced section.

According to a preferred embodiment, the whole of said elongated body, including its upper part or handle, its central part with its two different sections corresponding to two distinct cylindrical portions or to a single frustoconical portion, and its lower part, provided a portion of reduced section and a pointed end portion or "plug", consists of a single piece, advantageously by foundry or forging, while the striking bell and the flat support piece are patches.

According to an important additional characteristic of the invention, the handles of the ram have a lower end secured to the body of the sleeve, preferably by a long longitudinal weld, while their upper curved end freely penetrates into a longitudinal channel which opens to the surface d the upper end of the sleeve and has a depth greater than the length of the handle portion which penetrates therein.

Other features, as well as the advantages of the invention, will become apparent in the light of the description below.

• La figure 1 est une vue en coupe longitudinale du corps allongé d'un outil conforme à un mode d'exécution préféré de l'invention, dont
• la figure 2 montre le bélier, également en coupe longitudinale;
• la figure 3 montre ledit bélier en coupe transversale; et
• les figures 4 et 5 montrent, en perspective, deux modes d'exécution de la cloche de frappe et de la pièce d'appui.

In the attached drawing:

• Figure 1 is a longitudinal sectional view of the elongated body of a tool according to a preferred embodiment of the invention, of which
• Figure 2 shows the ram, also in longitudinal section;
• Figure 3 shows said ram in cross section; and
• Figures 4 and 5 show, in perspective, two modes of execution of the striking bell and the support piece.

It can be seen, in FIG. 1, that the elongated body of the tool, constituted, in the preferred embodiment described, in a single piece of foundry, a process which allows a body to be produced inexpensively in which the longitudinal fibers metal (steel for example) are preserved and thus offer a great resistance to tearing, includes: a cylindrical handle 1, having for example 30 mm in diameter and 900 mm long; a central part 2, composed of a cylindrical upper portion 20 having for example 50 mm in diameter and a cylindrical lower portion 21 having 50 mm in height and for example 35 mm in diameter, which corresponds substantially to the dimension of the circle most commonly used ankle scabbard entry; and a spindle 3, composed of a pointed bottom plug 32 having a height of 190 mm and a section of the same section as the ankle sheaths and of an upper portion 31, 260 mm in height and of reduced diameter equal to 28 mm in the example considered.

The upper portion 20 of the central part is capped with a bell 4 having for example an outer diameter of 80 mm and a height of 65 mm and fitting exactly on said upper portion 20, a central passage 41 allowing the crossing of its upper striking surface 42 by the handle 1. The bell rests at its base on the upper surface of a flat piece 5, 30 mm thick provided with a central circular preservation recess 51 having for example 60 mm diameter, and through which the portion 21 passes coaxially.

The lower surface 52 of the flat part 5 serves as a bearing surface and its largest dimension is for example equal to 250 mm.

Advantageously, this bearing surface is not circular, but comprises for example one of the forms lightened by recesses 57, 58 illustrated by FIGS. 4 and 5, where it can also be seen that the bearing part 5 is provided with reinforcing fins, such as 53 to 56, integral with the striking bell 4, while the bearing surface is provided with one or more longitudinal notches, such as 59, which facilitate the positioning on the ankle fins. Of course, the shape of the bearing surface will be adapted to the geometric configuration of the set of fins.

It will be noted that the central protruding part 2 has significant mechanical strength and makes it possible to constitute, on the one hand a fitting element 20 for the striking bell 4, on the other hand, a portion 21 which cooperates with the plug 32 for ensure the relative guiding of the dowel and the false stake.

The use of the striking bell makes it possible to increase the section of the striking surface with which the base of the ram cooperates, without thereby excessively increasing the section of the body of the tool, which must be as light as possible.

The plug 32 has, over its entire height, with the exception of the pointed part, a section such that it conforms perfectly to that of the ankle sheath, to within a few tenths of a mm, and lubrication is recommended to facilitate removal of the tool at the end of the driving operation. The very small thickness of the clearance prevents the penetration of the earth during sinking.

The intermediate reduced section 31 reduces the risk of the false stake sticking to the sheath.

The support piece 5, the bell 4 and even the central guide portion 21 and the plug 32 can be removably mounted (by screwing, or fitting) so as to be changed in the event of wear or breakage, or again, as regards the plug and the central guide portion, with a view to using the same tool for dowels having sheaths of different sections. As a variant, it is possible to give the central part 2 the shape of a truncated cone whose upper base will have a diameter of 50 mm for example and the lower base, a diameter of 35 mm. The section of this central part will then have no discontinuity and its lower base will also be connected without section discontinuity with a frustoconical upper part of the spindle 3. The flat part 5 will not, in this variant, have a central recess such as 51 figure 1, but will be directly fitted on the central part 2. -

In this variant, which is simpler to produce than that of FIG. 1, the frustoconical central part 2, by engaging at the start in the sheath of the ankle, will wedge the latter and, from the first shocks of the ram, the ankle will be flared by going up along the frustoconical central part 2, which will facilitate the introduction of the post at the end of the operation. No risk of crimping the ankle sheath exists.

In Figures 2 and 3, we see that the ram has a cylindrical sleeve 6 having for example 600 mm long, an outside diameter of 80 mm (equal to that of the striking surface 42) and an inside diameter of 31 mm (therefore , slightly higher than that of handle 1 on which it slides).

The relatively large height and the relatively small section of the ram give better sliding guidance with a greater stroke, and a very centered impact on the striking surface.

In the example described, four handles 7, 8, 9, 10 are provided, arranged with a uniform distribution at the periphery of the sleeve 6 and secured to the latter at only one of their ends. Indeed, it was found that the joining of the handle at its two ends would cause rigidity such that shock waves would break the junctions after a certain operating time. Preferably, the attachment of the handle is made at its lower part, by a longitudinal weld 71, which offers a very high resistance to tearing by the shock wave which arises nearby. The upper part of the handles is left free, which allows the dissipation of the shock wave; to avoid, however, secondary parasitic vibrations and deformations, this upper part is curved at a level higher than that of the upper end of the sleeve and its end descends to penetrate with a very small clearance in a channel 72 formed in the body of the sleeve annular and opening to the transverse outer surface thereof. A gap 73 is provided between the end surface of the handle and the bottom of the channel.

It goes without saying that, as was said in the abovementioned certificate of addition, one could, without departing from the spirit of the invention, truncate the handle 1 of the body of the tool and replace the upper part of the latter and the ram by the piston of a hydraulic cylinder, or by any other mechanical driving device, the advantages specific to the production of the central and lower parts of the body 1 according to the invention being preserved.

The tool of the invention cannot be used exclusively with the dowel described in the above-mentioned certificate of addition and patent, although it has been more particularly designed to adapt to it.

Claims (5)

1. In a tool for driving in and guiding pegs with a central sleeve for fixing posts or stakes in the ground, comprising a rigid elongated body having a lower part (3) whose section corresponds substantially to that of said sleeve, an upper part (1) for cooperating with a member applying a driving force and a projecting central part (2) comprising a lower transverse surface situated at a distance from the end of said lower part at least equal to and, preferably greater than, the height of the peg and an upper transverse surface, said central part (2) comprises: an upper portion (20) of larger section capped by a bell- shaped part (4) is provided with a central passage for the upper part (1) of the elongated body and whose upper surface (42) forms a striking surface; and a lower portion (21) whose section has a reduced dimension substantially equal to that of the circle inscribed in the sleeve of the peg, said lower portion being surrounded by a flat piece (5) whose lower surface (52) forms a bearing surface and whose upper surface is connected to the base of said bell (4).

2. The tool as claimed in claim 1, wherein said lower portion (3) or pin of said elongate body comprises a lower endmost portion (32) whose section has a dimension substantially equal to that of the sleeve of the peg and having a pointed end and an upper portion (31) connected to said lower portion (21) of the central part and of reduced section.

3. The tool as claimed in claim 1 or 2, wherein the assembly of said elongate body, including its upper part (1) or handle, its central part (2) with its two different sections (20-21), and its lower part (3) having a reduced section portion (31) and a pointed endmost portion or »plug« (32) is formed as a single piece, advantageously by casting or forging, whereas the striking bell (4) and the flat bearing piece (5) are added parts.

4. The tool as claimed in one of claims 1 to 3, further comprising a sleeve (6) forming a ram mounted for sliding on said upper part (1) of said elongate body, wherein the handles (7-8) of the ram have one lower end firmly secured to the body of the sleeve, preferably by a long longitudinal weld (71), whereas their upper curved end penetrates freely into a longitudinal channel (72) which opens into the upper endmost surface of the sleeve and has a depth greater than the length of the handle portion which penetrates therein.

5. The tool as claimed in one of claims 1 to 4, wherein said bearing piece (5) is provided with strengthening fins (53-56) integral with the striking bell (4) and has a bearing surface with one or more lightening notches (57-58) and guide grooves (59).

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