EP0167552A1

EP0167552A1 - Movable apparatus for driving into the ground various objects by percussion.

Info

Publication number: EP0167552A1
Application number: EP85900138A
Authority: EP
Inventors: Paul Moraly
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-01-10
Filing date: 1984-12-20
Publication date: 1986-01-15
Also published as: US4667746A; WO1985003095A1; ATE32361T1; JPS61500922A; DE3469196D1; FR2557898B1; IT8519021A0; ES539427A0; ZA8595B; CA1240525A; IL73994A0; IT1183076B; DE167552T1; EP0167552B1; FR2557898A1; AU3782785A; ES8606561A1

Abstract

Cet appareil comprend une structure porteuse (1) supportant un élément pendulaire (18) le long duquel coulisse une masse (19) dont les déplacements sont assurés par un câble (20). L'élément pendulaire (18) présente une structure tubulaire longitudinalement divisée en deux parties (24, 25) comprenant chacune au moins deux surfaces de guidage de deux zones opposées de la masse (19), de manière à pouvoir assurer à elles seules le guidage longitudinal de la masse, et des moyens de liaison (33, 38) de ces deux parties avec libre coulissement longitudinal de l'une des parties par rapport à l'autre. L'invention s'applique notamment à l'enfoncement dans le sol de chevilles à fourreau central.This apparatus comprises a supporting structure (1) supporting a pendulum element (18) along which slides a mass (19) whose movements are ensured by a cable (20). The pendulum element (18) has a tubular structure divided longitudinally into two parts (24, 25) each comprising at least two guiding surfaces of two opposite zones of the mass (19), so as to be able to ensure the guiding on their own. longitudinal mass, and connecting means (33, 38) of these two parts with free longitudinal sliding of one of the parts relative to the other. The invention applies in particular to the insertion into the ground of ankles with central sheath.

Description

MOBILE APPARATUS FOR PUNCHING MISCELLANEOUS OBJECTS INTO THE GROUND.

The present invention relates to a mobile device for driving into the ground, by percussion, of various objects and, in particular, of dowels intended for fixing posts or stakes.

It relates more particularly to a device of the type comprising a carrying structure intended to support a pendulum element along which slides a mass whose movements are ensured by a cable connected to a drive device having an operating cycle in two time, namely:

- a first stage during which the entrainment device lifts the mass at the level of the upper part of the pendulum element, and

- A second stage during which the driving device interrupts its traction force and starts to coast, so that it drops the mass under the effect of its own weight.

Thus, at the end of its fall, the mass can strike, directly or indirectly, the object that is desired push in and that has been previously arranged in line with the lower end of the pendulum element.

It turns out that making a device like this involves solving many problems.

A first problem results from the fact that as the element is pushed in, the point of impact of the mass moves downwards. Consequently, provision should be made for permanently adapting the travel of the mass and, consequently, its guidance, to the level of insertion of the object to be inserted. It should be noted in this regard that a possible solution to solve this problem may consist in using a pendular element of tubular shape whose inner surface is used for guiding the mass and to introduce initially, in the lower part of this tubular element, the object to be pushed in. Thus, during the insertion, the part of the object protruding outside the ground remains inside the tubular element and is guided, permanently, in the volume of passage of the mass.

However, this solution has the drawback of limiting the shape of the objects to be inserted, to the dimensions of the interior volume of the pendulum element. In addition, it is subject to frequent jamming, by deformation of the objects to be inserted, inside the pendulum element, under the effect of shocks, in particular in the case of hard ground.

The invention therefore firstly aims to eliminate these drawbacks. To this end, it offers a longitudinally extendable pendant element whose length adapts permanently to the height of the object during its insertion, and which ensures perfect continuity of the guiding of the mass which let this length be.

According to a characteristic of the invention, this element pendulum comprises a tubular structure, longitudinally divided into two parts each having at least two guide surfaces of two opposite zones of the mass so as to be able to ensure alone the longitudinal guide of the mass, the guide surfaces of the one of the parts being offset angularly with respect to those of the other part, and means for connecting these two parts with free longitudinal sliding of one of the parts with respect to the other.

According to a particularly advantageous embodiment of the invention, the above pendulum element as well as said mass have a section in the form of a quadrilateral. In this case, each of the two parts constituting the tubular element comprises two parallel profiles in the form of a cor¬ nity, of concavity facing each other. The opposite internal faces of these two sections are spaced from each other by a length substantially equal to that of one side of said quadrilateral. Furthermore, the profiles of each of these two parts are fixed to each other by their ends by means of two fixing devices, at least one of which consists of a tubular section of inner section in the form of a quadrilateral comprising internal walls which have two opposite angular regions on which are applied and fixed the external faces of said sections, and two angular guide regions.

The assembly of the two parts of the pendulum element is then carried out so that the profiles of one of said parts pass through the tubular section of the other part and are guided by the angular guide regions of this tubular section. and vice versa.

According to another characteristic of the invention, the pendulum element is connected, by its upper end, to the structure of the device by means of a mechanical gimbal connection integral with one of the above-mentioned parts so as to allow free swinging of the pendulum element in two perpendicular directions.

Furthermore, the lower end of the tubular element may include means for longitudinally guiding a driving-in tool and for guiding dowels with a central sheath intended for fixing in the ground posts or stakes and a type similar to those described in patent application No. 78 11279 of April 10, 1978 and certificate of addition No. 79 09679 of April 10, 1979, for: "Anchor intended for fixing in the ground of posts or stakes and device for driving this pin ", deposited in the name of the Applicant, these guide means being provided so that the mass comes into impact at the end of the stroke the upper end of the driving tool.

According to another embodiment of the invention, the mass can also comprise, fixed on its lower face, a pile-shaped part substantially coaxial with the pendulum element. This part may advantageously have a length slightly greater than that of said dowel so as to permanently produce, during the insertion of the dowel, a pilot hole. In this case, the lower end of the tubular element may comprise means allowing the head of the dowel head to be held in position, these means equipping the lower end of the part of the tubular element which is not located not connected to the aforesaid mechanical cardan link.

Another problem which the invention aims to solve relates to the development of a kinematic chain intended for the drive of the mass and which is adapted to the pendulai¬ re element described above.

Thus, according to another characteristic of the invention, the drive of the mass inside the pendant element is carried out by means of a cable actuated by a drive device mounted on the structure of the apparatus and which passes, by means of a system of return pulleys, inside the aforesaid mechanical gimbal connection.

To this end, the mechanical universal joint can include a first yoke substantially in the shape of a ϋ, that is to say comprising a core from which two wings run parallel. On the soul of this yoke is fixed an axis which extends parallel to the two wings, in the longitudinal plane of symmetry of the yoke and which includes two parts projecting beyond the yoke, on the side and d other of it. These two projecting parts are rotatably mounted in two respective bearings integral with the structure of the device.

Furthermore, the two wings of this first screed include:

- On the one hand, two coaxial holes inside which is mounted the axis of rotation of a pulley housed inside the clevis which follows, therefore, the movements of the element pendulum, and

- on the other hand, two coaxial pins respectively fixed on the outer faces of the two wings of the yoke, the axis of these two pins being located at a distance from the axis of rotation of the pulley, substantially equal to the radius of said pulley, and in a plane parallel to the core of the yoke and passing through the axis of said pulley.

This mechanical gimbal connection involves, at the upper part of the pendulum element and integral with one of said parts, a yoke structure comprising two parallel wings provided with two coaxial drillings res¬ pective in which come to engage the above swirls. It must also include at least one guide pulley rotatably mounted on the mobile structure of the device to guide the cable to the entrance of the mechanical connection.

According to another characteristic of the invention, the cable drive device consists of a rotary arm pivotally mounted by one of its ends on the structure of the device and driven in rotation from a engine, via a freewheeling type transmission device. This rotary arm carries, at its other end, a pulley mounted idly around an axis parallel to the axis of rotation of said arm. According to this device, the cable which is fixed by one of its ends to the mass, passes through the pulley of the mechanical universal joint, is guided by the guide pulley, then passes around the pulley of said arm and then returns substantially parallel to itself and is fixed, by its other end, to a fixed point of the structure. The operation of this device will be more particularly described below with reference to the drawings.

According to a particularly advantageous embodiment of the invention, the mobile structure of the device is mounted on three ground rolling means arranged in a triangle and each equipped with a device for adjusting the height of the structure.

Embodiments of the invention will be described below, by way of nonlimiting examples, with reference to the appended drawings in which:

FIG. 1 is a schematic perspective view of an apparatus according to the invention in an electrical version.

FIG. 2 is a schematic perspective view of the pendulum element used in the apparatus shown in FIG. 1. Figures 2a, 2b and 2c are views illustrating the principle of the pendulum member shown in Figure 2, this pendulum member being in the deployed position in Figure 2a, in the retracted position in Figure 2b and in cross section in Figure 2c.

FIG. 3 is a schematic perspective view of the mechanical gimbal connection device connecting the pendulum element of FIG. 2 to the support structure of the device of FIG. 1.

FIG. 4 is a schematic representation of the kinematic chain for driving the coulis¬ mass in the pendulum element shown in FIG. 2.

FIG. 4a represents a device for holding the cable on the traction sheave in order to prevent it from jumping at the time of the free fall of the mass.

FIG. 4b is a schematic section making it possible to illustrate the operation of the kinematic chain of FIG. 4.

Figures 5 and 6 are two longitudinal sections of the lower end of the pendulum element to illustrate two embodiments possi¬ ble of the tool for driving and guiding chevil¬ the central sleeve.

FIG. 7 is a theoretical diagram of an embodiment of an apparatus using an operating motor.

FIG. 8 represents, in perspective, the lower part of a pendulum element equipped with a device for holding the pin in the ground during the extraction of the tool, at the end of the operation. In the example shown in Figure 1, the movable apparatus for the insertion into the ground of various objects such as, for example, stakes or posts or even pegs intended for fixing posts or stakes comprises first of all a support structure 1 of tripod type, the feet of which extend along the edges of a volume in the form of a pyramid.

In this example, two of the legs of this structure each consist of a profiled beam 2, 3 while the third leg is constituted by two parallel beams 4, 5 slightly spaced from one another.

These three feet are connected to each other by means of crosspieces 6 of which only one is shown between the beams 2 and 3.

On the lower ends of the beams 2, 3 are respectively pivotally mounted two parallel wheels 8, 10 by means of a connecting device 11 allowing the height of the foot to be adjusted by means of a crank 12. Similarly, on the lower end of the two parallel beams 4, 5 are mounted two twin wheels 13, 14 by means of a connecting device 15 allowing the free orientation of the two wheels 13, 14 as well as a height adjustment of the foot by means of a crank 16.

At the upper end of this structure is fixed a plate 17 on the lower face of which is suspended, by means of a mechanical gimbal connection of the type shown in FIG. 3, a pendulum element 18 such as that of FIG. 2, inside which a mass 19 slides.

This mass 19 is connected to a cable 20 which passes inside the tubular element 18, then in the universal joint 21 then in a drive device 22 mounted on the two beams 4, 5 of the structure, the principle of which will be described with reference to FIG. 4.

This drive device 22 is itself driven by a geared motor group carried by the two beams 4, 5. The engine of this group can advantageously consist of an internal combustion engine. However, in the example shown, it consists of an electric motor 23 powered by a generator 23 'suspended on a gimbal so as to maintain a constant oil level guaranteeing the longevity of the group.

In the example shown in Figure 2, the pendant element 18 in the retracted state and the mass 19 have a square cross section. This pendulum element 18 is constituted by two longitudinal parts 24, 25 mounted to slide relative to one another, namely:

- A first part 24 comprising two parallel sections 26, 27 in the form of an angle iron, of concavities mutually facing each other and arranged so as to guide two opposite angular regions of the mass 19; these two sections 26, 27 are assembled to each other, at their upper ends, by means of a connecting piece 28 comprising two parallel cheeks 29, 30 provided with coaxial bores 31, 32, so as to make a hinge yoke and, at their lower part, by means of a tubular section 33 of square section, the internal walls of which have two opposite angular regions 34 on which the external faces are applied and fixed said sections 26, 27 and two angular guide regions 35, and

- A second part 25 comprising two parallel sections 36, 37 in the form of an angle, of concavities mutually facing each other and arranged so as to ensure the guiding the other two opposite angular regions of the mass 19; these two sections are assembled to each other at their upper and lower ends by two respective tubular elements 38, 39 of square section whose internal walls have two opposite angular regions 40, 41 on which are applied and fixed the external faces of said sections 36, 37 and two angular guide regions 42, 43.

The assembly of the two parts 24 and 25 of the tubular element 18 is produced in such a way that the sections 26, 27 of the part 24 pass through the tubular section 38 of the part 25 and are guided by the angular regions. guide 42, 43 of this tubular section 38 and, conversely, the sections 36, 37 of the part 25 pass through the tubular section 33 of the part 24 and are guided by the angular guide regions 35 of this tubular section 33.

It is clear that when the pendulum element 18 is in the deployed state (FIG. 2a), in the upper part, the mass 19 is guided along a first diagonal by the two angle sections 26, 27 of the first part 24 and, in the lower part, along the other diagonal by the two angle sections 36, 37 of the second part 25, so that the mass 19 is suitably guided and without any discontinuity from one end to the other of the tubular element 18.

As previously mentioned, the mass 19 which descends in free fall in the pendulum element is raised by a cable 20 which passes through the mechanical cardanic connection 21, so that it always remains in the longitudinal central axis of the pendulum element 18.

For this purpose, the mechanical cardanic connection comprises first of all, as shown in FIG. 3, a yoke hinge 50 in the form of a U on the core of which are fixed two coaxial pins 51 extending in the longitudinal plane of symmetry of the yoke. These two pins 51 are mounted in two respective bearings 52, 53 fixed on the plate 17 located at the upper part of the supporting structure 1.

The two wings of this yoke 50 also include two coaxial holes 54 inside which is mounted the axis of rotation 55 of a pulley 56 housed inside the yoke 50 and two coaxial pins 57, 58 respective¬ ment fixed on the two outer faces of the two wings of the yoke 50.

The axis of these two pins 57, 58 is located at a distance from the axis of rotation 55 of the pulley 56, substantially equal to the radius of the pulley 56 and in a plane parallel to the web of the yoke 50, passing by the axis of the pins 57, 58.

These two pins 57, 58 engage in the corresponding holes 31, 32 provided in the two cheeks 29, 30 of the connecting piece 28 of the first part 24 of the tubular element 18.

With reference to FIG. 4, the cable drive device 20 consists of at least one arm 60 rotatably mounted by one end on one of the two parallel beams 4, 5 of the structure 1 of the device and on which is rotatably mounted, at the other end, a pulley 61. This arm 60 is rotated from the gear motor 23 by a freewheel transmission system. In the example shown, the arm 60 is mounted idly on an axis 62 on which there is also rotatably mounted a second arm 63 driven in rotation by the gear motor group 23 by means of a chain transmission 64 and sprockets 65 ( figure 1).

This second arm 63 comprises a stop 66 extending in protrusion in the passage volume of the first arm 60 so as to be able to drive the latter in rotation in one direction.

According to this device, the cable 20 which is fixed by one of its ends to the mass 19, passes over the pulley 56 of the gimbal mechanical connection 21, is guided at the entry of this connection by a pulley of guide 67, then passes around the pulley 61 of the first arm 60 and then returns parallel to itself to come to be fixed at a fixed point P of the structure or to be wound on a drum intended to adjust the length of the cable 20.

The operation of the device described above is then as follows:

The mass 19 being at the low point of its stroke inside the pendulum element 18, the first arm 60 is in the high position and is rotated by the second arm 63, the resistant torque exerted by the cable 20 under the effect of the mass 19 on the pulley 61 exerted in the opposite direction to the direction of rotation exerted by the arm 63. At the end of this half-rotation stroke, the direction of the resisting torque is reversed by relative to the direction of rotation of the arm 63 and the first arm 60 emerges from the stop 66 and is rotated by the cable 20 at an angular speed greater than that of the second arm 63. The mass 19 then falls in free fall, strikes the insertion tool or the pin located at the end of the pendulum element and stops at the end of the stroke. A few moments later, the first arm 60 is again driven by the second arm 63 and a new cycle begins again.

Of course, the previously described device may advantageously include a device allowing the cable 20 to be kept under permanent tension. Such a device can conventionally involve a tension spring between the fixed point and the cable as well as a system of stop. It could also consist of a counterweight mounted on the cable 20 by means of a muffle.

Furthermore, instead of using only a single arm 60, the device could possibly include, as shown in FIGS. 1 and 4, two arms 60, 60 ′ rotatably mounted by one of their ends on the parallel beams 4, 5 and joined at the other end by a pulley 61, the space between the two arms 60, 60 'being cleared to allow the passage of the cable 20 during rotation.

In addition, to prevent the cable 20 from escaping from the pulley 61 at the time of the free fall of the mass, the pulley 61 can be equipped, as shown in FIG. 4a, with a holding device comprising two flanges parallel lateral rotatably mounted about the axis of the pulley 61 and extending on either side thereof. These two flanges are joined to each other by means of a massive piece constituting a ballast which tends to bring the two flanges back to the vertical position.

As previously mentioned, the apparatus according to the invention can be used for anchoring, in the ground, dowels 70 comprising a rigid part advantageously composed of metal plates shaped as fins 71, said rigid part forming a sheath 72 intended to receive, once the dowel 70 has been driven into the ground, the base of a post or stake. It is known that the driving in of these pegs can advantageously be carried out by means of a driving tool comprising a rigid elongated body 73 having at least, in its lower part, the shape of a false pile of slightly longer length. greater than that of the ankle and, at the upper end of this false pile, a shouldered portion 74 intended to transmit a driving force on the upper face of the ankles.

Thus, in the example shown in Figure 5, the driving tool is incorporated into the mass 19 and consists - He* -

simply in a false pile 76 mounted on the underside of the mass.

In this case, the mass comes directly to bear on the upper face of the pins and the pendulum element 18 comprises, at its lower part, means for centering said pins.

By cons, in the example shown in Figure 6, the driving tool comprises, in addition to the false pile 73 and the shouldered portion 74 for driving the pins 70, a rod 77 mounted axially sliding in a bearing 78 provided at the lower end of the pendulum element 18 and on the head of which the mass 19 comes.

It is clear that the tool which slides in the bearing 78 situated at the lower part of the pendulum element alone suffers the shocks thus preserving the whole of the pendulum element and of the apparatus. The pendulum then follows with a slight delay due to its inertia the descent of the tool.

In this case, the head 80 of the rod 77 may have a rounded shape and the underside of the mass 19 may include a central recess 81 in which said rounded shape of the head 80 of the rod 77 can engage. This arrangement thus allows good centering of the rod 77 during the impact of the mass 19. In addition, means can be provided for securing the head 80 of the rod 77 to the mass 19, so as to facilitate the extraction of the driving tool, once the pin 70 is pressed. In the example shown, these fixing means consist of a key or a pin 80 ′ in the shape of a U engaging in a groove 82, 84 formed in the head 80 of the rod 77 and in the recess ent 81. This provision therefore allows the lifting of the bottom of the pendulum element.

Thanks to the mechanical gimbal connection 21, the pendant element 18 can be driven in any direction longitudinal and transverse, so as to locate at will its longitudinal axis at a precise point by adjusting the height at each support point on the ground of the structure by means of the cranks 12, 16. These height adjustments allow in particular:

1) to correct the trajectory of the pendulum element to arrive at a precise point,

2) absorb any loss of land by leaving the device vertical,

3) adjust the device by lowering or raising the whole assembly to take account of irregularities in the ground (hollows or bumps).

As previously mentioned, the device can comprise, for its traction, a winch 100 which is parallel to the axis of the wheels 8, 10, 19, 14 and suitably centered, so as to obtain an advance of the device in a precise direction. determined even in very steep or swampy areas.

This winch can be equipped with a tachometer allowing the automatic calculation of the intervals between each sinking operation in the ground by the tool.

According to the embodiment of the invention shown in Figure 7, the geared motor group 23 may consist of an internal combustion engine 101 with gearbox 102, possibly automatic, differential 103 and centrifugal clutch. In this case, one of the sides of the differential can be coupled to the aforesaid second arm 63 for lifting the mass, the other side being used to actuate the winch. It then suffices to block one of the sides of the differential for the other to be operational and to accelerate or slow down the engine to start the differential or stop everything. Furthermore, it proves useful to provide safety contacts for the mass when the latter reaches its highest point just before its fall and on the pendulum element 18 when it reaches the end of the development stroke, in order to '' avoid mass impact on the pendulum element. Of course, it is possible to increase the stroke of the mass inside the pendulum element by acting on the height of the ground support points of the structure 1 in the manner previously indicated. It is also possible to reduce the weight of the mass 19 by placing a compression spring 90 in the pendulum element 18 at a level corresponding to the high position of the mass 19. This spring 90 then has the effect of projecting the mass 19 downwards and considerably increase the impacts without having to odify the weight of the mass 19.

To increase the safety of the device, it may include safety grids surrounding the pendulum element 18 and fixed on the tubular sections 33, 38, so as to prevent any access to the voids which occurs when the pendulum element 18 develops.

With reference to FIG. 8, the device for holding the dowel 70 pressed in on the ground, during the extraction of the tool, comprises a support piece 105 on the dowel on the ground, held by rods 106 slidably mounted on the pendulum element 18 and which can be blocked for example by means of clamping screws on the upper part 24 of the pendulum element 18.

Claims

Patent claims

1. Apparatus for driving objects into the ground by percussion, this apparatus comprising a support structure (1) supporting a pendulum element (18) along which slides a mass (19) whose movements are ensured by a cable (20) connected to a drive device having a two-stage operating cycle, namely, a first step during which the drive device acts on the cable (20) to lift the mass at the level of the upper part of the tubular element and a second time during which the drive device interrupts its tensile force on the cable (20) and starts to coast-free, so as to allow the mass to drop ( 19) under the effect of its own weight, characterized in that the pendulum element (18) has a longitudinal tubular structure ent divided into two parts (24, 25) each comprising at least two guide surfaces of two "opposite" zones mass (19), so as to be able to ensure alone the longitu¬ dinal guidance of the mass, the guide surfaces of one of the parts (24) being angularly offset with respect to those of the other part (25), and connecting means (33, 38) of these two parts with free longitudinal sliding of one of the parts relative to the other.

2. Apparatus according to claim 1, characterized in that the said mass (19) has a cross section in the form of a quadrilateral and the internal surface of the pendulum element (18) has a cross section in the form of a quadrilateral section substantially complementary to that of the mass (19), in that each of the two parts constituting the tubular element (18) comprises two parallel sections (26, 27, 36, 37) in the form of angles, of concavity mutually in look, in that the profiles (26, 27, 36, 37) of each of these two parts (24, 25) are fixed to each other by their ends by means of two respective fixing devices, at least one of which consists of a tubular section (33, 38) of internal section in the form of a quadrilateral comprising internal walls which have two opposite angular regions to which are applied and fixed the external faces of said sections (26, 27 and 36, 37) and two angular guide regions, and in that the assembly of the two parts of the pendant element (18) is carried out so that the sections ( 26, 27) of one of said parts (24) pass through the tubular section (38) of the other part (25) and are guided by the angular guide regions of this tubular section (38), and Conversely.

3. Apparatus according to one of claims 1 and 2, characterized in that the pendulum element (18) is connected, by its ^" upper end, to the structure (1) of the apparatus by means of a mechanical universal joint (21) solidai¬ re from one of the above two parts.

4. Apparatus according to claim 3, characterized in that the aforesaid mechanical gimbal connection (21) comprises a joint yoke (50) in the shape of a U on the core of which is longitudinal ent an axis (51) of which the two ends are rotatably mounted in two respective bearings (52, 53) integral with the structure (1) of the device, in that the two wings of this yoke include two coaxial holes (54) inside which is mounted the axis of rotation (55) of a pulley (56) housed inside the yoke (50), and two coaxial pins (57, 58) extending transversely towards the outside of the yoke (50) , which engage in two corresponding holes (31, 32) provided on two cheeks (29, 30) forming a clevis integral with the upper end of one of the two abovementioned parts (24) of the tubular element (18).

5. Apparatus according to claim 1, characterized in that the axis of the above pins (57, 58) is located at a distance from the axis of rotation of the pulley (56), substantially equal to the radius of the pulley (56 ) and in a plane parallel to the core of the yoke (50), passing through the axis of said pulley (56).

6. Apparatus according to one of the preceding claims, characterized in that it further comprises a guide pulley (67) of the cable (20) at the entrance to the mechanical linkage (21).

7. Apparatus according to one of the preceding claims, characterized in that the cable drive device (20) consists of at least a first rotary arm (60). pivotally mounted, by one of its ends, on the structure (1) of the apparatus and driven in rotation from a motor unit (23), by means of a type of transmission device freewheel, this rotary arm (60) carrying, at its other end, a pulley (61) mounted idly around an axis parallel to the axis of rotation of said arm (60), and in that the cable (20 ), which is fixed by one of its ends to the mass (19), passes through the pulley (56) of the universal joint (21), is guided by the guide pulley (67), passes then around the pulley (61) of said arm (60), then returns substantially parallel to itself and is fixed, by its other end, to a fixed point (P) of the structure (1).

8. Apparatus according to claim 7, characterized in that the connection of the cable (20) to the structure of the apparatus is effected by means of a device (68) allowing the length of the cable to be adjusted ( 20) and / or a means for keeping said cable (20) under tension.

9. Apparatus according to one of the preceding claims, characterized in that it further comprises a cable tensioner.

10. Apparatus according to one of claims 7, 8 and 9, characterized in that the rotary drive of the aforesaid first arm (60) is provided by means of a second arm

(63) driven in rotation by the motor unit (23), coaxially with the first arm (60), this second arm comprising a part forming a stop (66) extending in the passage volume of said first arm (60 ).

11. Apparatus according to one of the preceding claims, characterized in that its structure (1) is equipped with three ground support means arranged in a triangle and each equipped with a device for adjusting the height of the structure ( 1).

12. Apparatus according to claim 11, characterized in that said support means are equipped with ground rolling means (8, 10, 13, 14).

13. Apparatus according to one of the preceding claims, characterized in that it comprises a winch to ensure its movements in a straight line.

14. Apparatus according to claim 13, characterized in that said winch is equipped with a tachometer.

15. Apparatus according to one of the preceding claims, characterized in that the engine group (23) consists of an assembly comprising an internal combustion engine, a clutch, a reduction gear and a differential, one of the sides of which is coupled the above drive device (22) for the mass (19) and the other side of which is coupled to said winch.

16. Apparatus according to one of the preceding claims, characterized in that, with a view to driving in the pins with central sheath (70), it comprises a driving tool comprising a rigid elongated body having at least, in its lower part, the shape of a false stake (73) of length slightly greater than that of the pegs

(70), and at the upper end of this false pile, a shouldered part (74) intended to retransmit on the upper face of the pins (70) the driving force exerted by the mass (19).

17. Apparatus according to claim 16, characterized in that said driving tool is solidai¬ re from the underside of the mass (19).

18. Apparatus according to claim 16, characterized in that said driving tool comprises, beyond said shoulder part (74), a rod (77) mounted axially sliding in a bearing (78) provided at the extrem lower part of the pendulum element (18) and on the head of which comes to bear said mass (19).

19. Apparatus according to claim 18, characterized in that the head (80) of the said rod (77) has a rounded shape and the underside of the mass (19) comprises a central recess (81) into which can come s 'Engaging said rounded shape of the head (80) of the rod (77).

20. Apparatus according to one of claims 18 and 19, characterized in that it comprises means for securing said rod (77) to said mass (19).

21. Apparatus according to one of the preceding claims, characterized in that it further comprises a compression spring (90) mounted inside the pendulum element (18) at a level corresponding to the high position of the mass (19).

22. Apparatus according to one of the preceding claims, characterized in that it further comprises a device for holding the pin in the ground, during the extraction of the tool, which comprises a part d 'support (105) bearing on the ankle and held by rods (106) slidably mounted on the pendulum element (18) and coming to be fixed in the upper part thereof.