EP0039654B1 - Pyrotechnic device for anchoring piles or similar objects in the soil - Google Patents

Description

The present invention relates to a pyrotechnic device for anchoring piles or other similar objects in the ground.

The technical sector of the invention is that of equipment operating under the ignition of a powder for fixing various apparatus to the ground: pipes, electric cables or other ...

Devices are already known for driving piles or other objects into the ground, for example coring tools and which operate by pounding or threshing.

French patent 1,518,931 describes a device for threshing in a liquid medium operating under the effect of charges composed of a fuel and an oxidizer, which device comprises a piston guided vertically and connected to said device by tension springs, which bring back the piston in the high position after each firing. The piston strikes an anvil which is brought into contact with the pile, which is guided in vertical translation and is arranged coaxially with the piston and the anvil. The apparatus also includes means for igniting charges. The piston / anvil assembly and the means for igniting the charge are slidably mounted on two lateral rods fixed to an anti-recoil tank.

The pile is driven into the ground by threshing and requires several successive strikes.

In the context of underwater works in particular, pyrotechnic means have already been used to produce anchoring devices intended mainly for anchoring ships. Such devices have the disadvantage of causing, when the system is ignited, a shock wave. These devices cannot therefore be selected for use, for example on an oil site where pipes, apparatus and electrical cables are already installed.

Australian patent 24 223/67 relates to means and a method for anchoring piles, in particular for positioning floating equipment. The pile resting on the ground and held by a tripod is brought into contact with an explosive charge located at its upper part which, when ignited, projects it towards the ground.

Alternatively, the stake is placed in a tube held in a vertical position by guy lines. The explosive charge is placed above the water and is crossed by a rod fixed to the upper part of the cylinder head tube and to which is suspended the pile which is engaged in said tube. At the time of ignition, the rod is destroyed and the stake is thrown towards the ground. The tube extends from sea level to the bottom.

In another variant, the tube is shorter and is suspended from a buoy.

US Patent 2,583,965 relates to an underwater anchoring device comprising a head forming a cylinder head extended downwards by a tubular part in which the stake is engaged. This is abutted in front of an explosion chamber and is held in position by a shear pin. For wooden piles, the upper part of the pile is covered with a metal cap. The device also includes a guide tube emerging above the water, which tube is coaxial with the communication chamber and communicates with it. The propulsion of the pile is obtained by an explosive charge contained in a container in the shape of a warhead and comprising a detonator. The container is left in free fall guided by said tube; as soon as the container meets the pile head, the load explodes and the pile is propelled to the ground side.

An objective of the present invention is to anchor piles in the ground or other anchoring members, or to drive tools into the ground to drill cores for the purpose of taking soil samples.

Another objective is to optimize the rates for the installation of said piles, objects or tools to be cored, without however being required to make large financial investments.

Another objective is to carry out the abovementioned works in the field of underwater activities and in particular within the framework of oil research at sea.

The major problem to be solved, when implementing pyrotechnic processes underwater, is the suppression of the shock wave produced during the deflagration so that the device can be used by a diver or a submarine on an oil site in particular.

The problem is solved and the above objectives are achieved by the pyrotechnic device for anchoring piles or other similar objects in the ground, comprising in combination a stake and means for driving said stake into the ground, which means comprise a cylinder head fitted of a device for igniting a cartridge and extended downwards by a guide tube comprising, at its lower end, means for evacuating the air contained in the tube, characterized in that the tube is intended for receive either a pile or a movable mass to strike said pile, and in that the pile, which is introduced into the guide tube or the mass comprises, at its upper part, a head comprising shearable means for maintaining in position in the tube, before firing, said stake or said mass, so as to put the head in abutment on the breech, which comprises a housing of said cartridge, this housing being extended on the side of the location of the head by a ch amber gas expansion, delimited at its lower part by said head, the device further comprising means for perfecting the seal of the gas expansion chamber at the junction of the head and the cylinder head.

In such a device whose head of said pile or of said mass comprises at its periphery a collar, said collar forms a shoulder to come to bear on a circular bearing, reserved in the cylinder head, substantially at the level of the upper end of the guide tube, which head comprises, at the junction of the collar and the head body, a zone of least resistance to cause, at the time of the firing, the separation by shearing of the collar and the head body.

The cartridge housing and the gas expansion chamber are reserved in a removable part, engaged in the center of the breech and coaxial with the guide tube, which removable part is, before firing, supported on said head.

In one embodiment, the pile head is threaded and is screwed to the upper end of the pile, which is also threaded, so that the thread, reserved for the periphery of the pile, extends below the pile head when it is flush with the upper part of the pile, in order to perfect the anchoring of the pile in the ground after firing by screwing the head to the pile. This comprises a ring, arranged approximately at the lower third relative to the length of the pile, which projects beyond the periphery of the latter to slide with a slight play in the guide tube, which ring is made of soft metal and is adjusted tightened on the pile to allow a relative movement between the ring and the pile at the time of the firing and to ensure the shock absorber function when it is inserted between the pile head and the ground to absorb the excess energy developed by the explosion charge.

In one embodiment, the ring takes the form of a coil and has, at each of its ends, a peripheral surface to reduce friction and improve the guidance of the pile in the guide tube.

In its underwater version, the guide tube comprises, at its lower part, a sleeve comprising, in the extension of the tube, an opening coaxial with the latter, which is closed by a removable sealing cap, which is driven out on each shot, and in addition the sleeve includes a valve and means for connecting a vacuum device to create a vacuum in the guide tube and check its tightness before the shot.

In this version, the device comprises, at its upper part, a wing forming a screen around the breech to use the energy developed by the explosion-proof charge at the time of the firing due to the recoil.

This wing adopts the shape of a cone whose wall diverges from bottom to top, which comprises a plurality of orifices distributed at its periphery in order to allow, before firing, the descent of the device into the aquatic medium along a substantially vertical axis. .

In one embodiment where the pile comprises, at its lower end a warp-shaped end, an explosive charge placed in a chamber reserved in the axis of the pile, longitudinal grooves made in the wall of said chamber to constitute rupture lines and means for igniting the charge, said chamber is located clearly above the ogival end so as to cause, when the charge explodes, the rupture of the wall of the chamber along said lines and the deformation towards the outside of the metal strips which they delimit, with a view to causing a bulge of the pile at this point to ensure its anchoring in the ground.

Said pile, which is tubular, comprises, on the side of the warhead, a ring-shaped partition comprising a central duct of small section closed by a metal cover of low resistance, said ring thus located in the tube playing the function of '' a nozzle and delimiting on the one hand between it and the pile head, a chamber closed at the pile head by a removable shutter, this chamber containing a synthetic resin, and on the other hand another smaller chamber volume located on the side of the warhead and containing the explosive charge and the means for igniting said charge, the latter being separated from said ring by at least one felt flock.

In another embodiment, the pile comprises on the one hand, on the side of the ogival head, a partition constituted by a thin pad, delimiting a chamber containing a synthetic resin and in front of which pad is arranged a solid perforating member of the warhead and arranged perpendicular to the pellet, so as to pierce the latter at the moment when the stake meets the ground, by the fact of the relative movement of the warhead and the stake and on the other hand at the level of the head pile, a removable shutter closing the chamber in which the resin is located at its upper part and, so as to be protected by the shutter, a partition forming a valve support for injecting into the chamber a charge of compressed gas, maintained prisoner before firing in the part of the chamber located between the valve support and the resin to expel the latter through openings reserved at the periphery of the warhead.

In another embodiment where the device comprises said mass, the pile is, before firing, in the extension of the guide tube in which the mass moves, which pile is in contact with the seal sealing the sleeve located at the lower part of the guide tube by means of an independent moving part, said device further comprising means for aligning, before firing, said tube and said stake and for guiding the latter during firing.

The alignment of the guide tube and the pile and its guidance are obtained by means of a mount which surrounds the guide tube and the pile and the sleeve cooperates by its periphery with the side wall of the mount, which is coaxial with the tube and at the stake, the lower part of the frame forming a central opening in which the stake has passed and surrounding it with slight play, as well as a centering block sliding just on the guide tube and closing the frame at its part superior. Said frame is supported on a stopper extending around the periphery of the pile.

The pile head, also called anvil, is separable from the pile and comprises, at its upper part, a central cylindrical housing coaxial with the pile and the guide tube, in which housing is disposed a damping disc covering the bottom of the housing, which disc is surmounted by a metal disc, centered by said housing by cooperating by its peripheral edge with the side wall of this housing, which metal disc is in contact with the cover located at the base of said sleeve.

The mass is in the form of a full cylinder, with a diameter less than the inside diameter of the guide tube, one end of said cylinder is threaded to receive the head with a shearable flange, which mass is hollowed out in its central part, this part being occupied by a material of high density to weigh it down.

The result of the invention is the installation, in the ground or in the sea floor, of piles or other objects such as for example coring tools, by means of pyrotechnic devices which do not produce a shock wave capable of cause damage to the environment of the implantation device.

Such a device makes it possible, from a tool of a simple design, to carry out the anchoring of piles in the ground both on land and at the bottom of the sea and whatever the depth: 1000 meters and more .

In its design with threshing mass, the device is compact and of a low weight: 30 to 35 kg in the air and is capable of producing very important energies. These energies are comparable for example to those produced by hammers having a mass of 5.4 tonnes, with a fall height of three meters or even a mass of 18.15 tonnes with a fall height of 0.862 meters.

• la figure 1 est une demi-vue en éléva- tion/demi-vue en coupe longitudinale d'un dispositif selon l'invention dans sa version « terrestre •,
• la figure 2 est une vue partielle en coupe à plus grande échelle de la disposition du pieu dans le dispositif, la tête de pieu étant insérée par sa couronne entre la culasse et le tube-guide,
• la figure 3 est une demi-vue en éléva- tion/demi-vue en coupe longitudinale d'un dispositif selon l'invention dans sa version « marine •,
• la figure 4 est une vue en élévation/coupe d'un pieu d'ancrage,
• la figure 5 est une vue en coupe longitudinale d'un dispositif selon l'invention dans sa version « marine avec moyens de battage pour enfoncer dans le sol par frappage, par exemple des pieux ou des outils à carotter,
• la figure 6 est une vue en coupe suivant la ligne VI-VI de la figure 5,
• la figure 7 est une vue en coupe suivant la ligne VII-VII de la figure 5,
• la figure 8 est une vue en coupe suivant la ligne VIII-VIII de ladite figure,
• la figure 9 est une vue en coupe schématique d'un pieu d'ancrage selon l'invention comportant une charge de résine et des moyens pyrotechniques pour obtenir la déformation du pieu le long de lignes de rupture réservées à sa partie inférieure, pour chasser la résine par ladite partie déformée après le tir dans le but de renforcer l'ancrage du pieu dans le sol,
• la figure 10 est une vue en coupe d'un pieu d'ancrage selon l'invention comportant une charge de résine et de gaz comprimé et des moyens pour libérer la résine sous l'effet du gaz afin de renforcer après le tir l'ancrage du pieu dans le sol,
• la figure 11 est une vue en coupe de l'ogive du pieu suivant la ligne XI-XI de la figure 10.

Other advantages and characteristics of the invention will become apparent on reading the description of various preferred embodiments of the invention given by way of examples, with reference to the appended drawing in which:

• FIG. 1 is a half-view in elevation / half-view in longitudinal section of a device according to the invention in its "terrestrial" version,
• FIG. 2 is a partial view in section on a larger scale of the arrangement of the pile in the device, the pile head being inserted by its crown between the cylinder head and the guide tube,
• FIG. 3 is a half-view in elevation / half-view in longitudinal section of a device according to the invention in its "marine" version,
• FIG. 4 is a view in elevation / section of an anchor pile,
• FIG. 5 is a view in longitudinal section of a device according to the invention in its "marine" version with threshing means for driving into the ground by striking, for example piles or coring tools,
• FIG. 6 is a sectional view along line VI-VI of FIG. 5,
• FIG. 7 is a sectional view along line VII-VII of FIG. 5,
• FIG. 8 is a sectional view along line VIII-VIII of said figure,
• Figure 9 is a schematic sectional view of an anchor pile according to the invention comprising a resin charge and pyrotechnic means for obtaining the deformation of the pile along rupture lines reserved at its lower part, to drive the resin by said deformed part after firing in order to strengthen the anchoring of the stake in the ground,
• Figure 10 is a sectional view of an anchor pile according to the invention comprising a charge of resin and compressed gas and means for releasing the resin under the effect of gas in order to reinforce the anchor after firing stake in the ground,
• FIG. 11 is a sectional view of the warhead of the pile along the line XI-XI of FIG. 10.

Reference is first made to FIGS. 1 and 2 of the drawing which illustrate a pyrotechnic device according to the invention in its terrestrial version and in one embodiment. This device is intended either to anchor piles in the ground, or to drive core tools to take sediment samples on consolidated soil. It consists of a cylindrical guide tube 1, intended to guide the pile during firing. In its vertical position, it comprises, at its upper part, a cylinder head 2, comprising two parts 2 _{1/2 2} assembled together.

The cylinder head 2 is of a cylindrical shape, so that the two parts 21/2 ₂ are coaxial.

The guide tube 1 has an additional thickness at its upper part to form a shoulder 1a and is engaged in the part 2 ₂ of the cylinder head, which is hollowed out in its center to allow the guide tube 1 to be inserted therein, which comes in abutment by its shoulder 1a on another shoulder 2 ₂ reserved in the cylinder head.

The part 2 _z of the cylinder head has a peripheral groove 2 ₂ b formed in the inner face of its wall in which groove is disposed a seal 3, for example an O-ring. Said part 2 ₂ is threaded at its outer periphery to form strong threads of a trapezoidal cross section.

Part 2 ₁ has in its center a cylindrical housing 2 ₁ a, which is threaded on the inner periphery of its open end 2 ₁ b, to form threads corresponding to the threads of part 2 ₂ and thus allow the two parts to be screwed 2 _{1/2 2} together.

The cylinder head 2 comprises a removable part 4 comprising a central cylindrical housing 4a for receiving a cartridge 5.

The upper wall 2 ₁ c of the part 2 ₁ has in its center, a circular orifice 2 ₁ d and the removable part 4, which is cylindrical, is engaged, by its part ₄ b, in the said orifice 2 ₁ d. The part 4 comprises a part of larger diameter 4c, which is connected to the part 4b by a truncated cone 4d and is engaged in the part 2 ₂ of the cylinder head which it completely closes. The part 4c comprises in its base and on the side of the pile 6, an annular groove 4e, for example of a rectangular cross section in which is placed a seal 7, for example an O-ring.

The removable part 4 also comprises, in the extension of the housing 4a and on the side of the part 4c, a cylindrical chamber 4f, which is coaxial with the housing 4a and opens out on the side of the pile 6. This chamber 4f constitutes the gas expansion chamber .

The cylinder head is equipped at its upper part with a firing device 8 of a perfectly known design.

The guide tube 1 has, at its lower part, vent holes some of which 1b are perpendicular to the generatrices of the tube and others 1c are oblique with respect to said generatrices.

The assembly 1, 2, 8 is carried by a frame which can be fixed to a vehicle, so that the end of the pile is at a distance from the ground at least equal to its length to avoid the reaction of the ground when the impact of said stake.

The pile 6 is cylindrical and has, at its upper part, a pile head 10. The lower part 6a is tapered and takes the form of a warhead.

The outside diameter of the pile 6 is much smaller than the inside diameter of the guide tube 1.

The upper part of the pile is threaded at 6b to allow the fixing of the pile head 10, the thread 6b extends below the pile head to allow, after firing, to perfect the anchoring by screwing the head 10 and its blocking in the ground or against a support plate which will be discussed later.

The pile head 10 is in the form of a cylindrical part pierced at its center and threaded so that it can be screwed around the pile 6, which part has an outside diameter slightly smaller than the inside diameter of the guide tube 1 to guide the end of the stake during the firing and also center the stake in the guide tube.

The head 10 comprises, at its upper periphery, a flange 10a, which, when the pile is engaged in the guide tube, is supported on the shoulder 1d formed by the reinforced part 1a of the guide tube.

To introduce the dolly 6 into the device, separating the two elements 2 _{1/2 2} of the yoke engaging the tube 6 in the guide tube 1, there is a cartridge 5 in the removable part 4 that is placed on the pile head 10, which part 4 is centered by the element 2 ₂ of the cylinder head.

Depending on the ejection force of the pile that it is desired to obtain, one can have, in the gas expansion chamber 4f, one or more metal pellets in order to vary the volume.

There is also created, at the junction of the flange 10a and the head body 10, a zone of least resistance by making a groove 10c from the upper face of the pile head and the depth of which is determined taking into account various parameters: nature of the metal constituting the pile head 10, desired ejection force, volume of the chamber 4f and the power of the cartridge 5.

To promote the shearing of the flange 10a, another groove 10d is reserved below the latter, which is adjacent to the flange and is formed at the periphery of the pile head 10.

The tightness of the chamber 4f is obtained by the annular seal 7.

The pile 6 also includes a ring 11, which is adjusted tightly around the pile while allowing relative movement with the latter. This ring takes the form of a “coil to determine two ranges 11a located at its ends. The bearing surfaces 11a are of a diameter slightly smaller than the internal diameter of the tube 1, so that the pile 6 can move in the tube. The particular shape of the ring 11 ensures good guidance of the pile while reducing friction during firing. This ring 11 is made of soft metal, for example lead to also ensure the function of a damping member when the head 10 comes into contact with the ground. Originally, it is arranged approximately at the bottom third relative to the length of the pile 6. At the time of the firing and as soon as the ring meets the ground, the pile 6, under the residual thrust of the gases, continues its penetration into the floor by sliding in the ring 11.

The ring 11 also performs the function of an anti-buckling member when the pile comes into contact with the ground.

The lower end of the pile comprises a warhead 6a of treated steel with a safety pin 12, and comprising a central cylindrical recess 6c (FIG. 4) about ten centimeters from its lower end. In this recess 6c is housed an explosive micro-charge 13, initiated by means of a micro-delay in order to cause the expansion of the pile in the ground after its insertion and to ensure the anchoring and its good resistance to tearing in the longitudinal axis of the pile.

As illustrated in Figures 1 and 4, the pile 6 has at its periphery, above the warhead 6a and in the wall of the recess 6c, longitudinal grooves 6d which constitute rupture lines delimiting bands . Said strips, deformed by the explosion of the load 13, give this part of the pile the general shape of a "lantern because of the large openings left between them and their deformation towards the outside. The shape of said part of the pile after firing is illustrated in phantom lines 6e in FIG. 4.

In order to perfect the anchoring of the pile, in particular depending on the nature of the soil, and the cracks that may have been created at the time of the explosion of the micro-charge 13, it is also planned to drown the lantern in a water-curable synthetic resin.

To allow the injection of this resin, the pile, according to an embodiment illustrated in Figure 4, preferably comprises a central conduit 6f extending from its upper end to the cylindrical recess 6c, which forms a cylindrical housing 6g into which opens the conduit 6f.

A 6h threaded plug is screwed into a thread reserved for the upper end of the conduit, which is closed at its lower part by means of a pellet 6j, made of low resistance metal, for example aluminum. A flock 14 is disposed in the housing 6g between the pellet 6j and the load 13. This flock is intended to absorb a part of the shock wave so that the explosive acts radially and not axially, to form the "lantern".

After firing, we unscrew the plug 6h and inject the resin through the central duct 6f, which, first occupying the recess deformed by the cartridge 13, flows through the openings delimited by the strips 6e to infiltrate in the cracks and cavities 15 created in the ground by the explosion, which forms all around the pile 6 an area occupied by the resin which, after hardening ensures the connection of the pile and the ground.

Figures 10 and 11 illustrate another embodiment of a pile 6 without expansive head, which is constituted by a threaded tube on the outside at one end to receive the pile head 10. Its other end has a cylindrical constriction 6u and is closed by a cover, constituted by a metal pellet 6p welded to the pile and delimiting a cylindrical chamber 6q. This chamber 6q is closed at its upper part by a part 41 constituting a valve support, which is screwed into the pile on the side of the head 10. To allow the positioning of the part 41, the internal section of the pile is enlarged and is threaded and forms a shoulder 6v on which the part 41 is supported. This part extends into the chamber 6q and has a peripheral groove 41a in which is disposed a seal 43, for example an O-ring.

The part 41 is pierced and threaded in its center to receive an inflation valve 42. A shutter 40, in the form of a cylindrical plug, is screwed into the pile and covers the valve 42. This plug 40 has the function of protecting the valve during of the shot and after being screwed, it is flush with the upper part of the stake.

The warhead 6a comprises a cylindrical housing 6t, the internal diameter of which is slightly greater than the external diameter of the constriction 6u of the pile, which is partially engaged in said housing 6t. This housing is extended by a coaxial cylindrical part 6w which determines a 6x shoulder.

The warhead has four grooves 6s, formed along perpendicular planes (Figure 11) which open into the housing 6t, as well as a perforating member 6r coaxial with the tube and the warhead and embedded in the warhead. The perforator 6r is in the form of a cylindrical rod pierced at its center to form a tubular part, which is engaged in a blind hole 6y reserved in the warhead. The tubular part is cut into a whistle at 6r, at its end, which is placed near the cover 6p. This perforator also has holes 6r ₂ at its periphery, for example four in number. As illustrated in Figure 10, the warhead is before firing fixed by gluing on the neck 6u and is at a distance from the shoulder 6z, so that it can slide until it comes to the side of said shoulder after rupture of the glue joint when fired.

The shoulder 6x, due to the formation of the notches 6s, forms four stops on which the tube rests after the firing.

Before its installation in the cylinder head 2, the part 41 is removed and the chamber 6q of the pile is filled for example with 20 c.c. near a synthetic resin hardening with humidity 39. The part 41 is replaced in its housing.

Through the inflation valve 42, compressed air is injected into the upper part of the chamber 6q, free of resin, to put the resin 39 in compression. For example, for a pile with a smaller diameter of 16 mm and for a depth of 20 m. and for a volume of 20 c.c. of the gas chamber, the required pressure is 20 bars.

The protective cap 40 is put back in place above the valve 42.

During the impact of the pile in the ground, the perforating member 6r, integral with the warhead 6a, pierces the pellet 6p which retains the resin 39. The overpressure created by the injection of compressed air into the available volume ( 20 cc approximately) causes the forced flow of the resin which passes through the holes 6r ₂ and the notches 6s, spreads outside and around the pile thus strengthening its anchoring in the ground.

Another embodiment of a pile 6 with an expansive head according to the invention is illustrated in FIG. 9 of the drawing. The pile 6 consists of a tube at the upper end of which is fixed a pile head 10. This is screwed around the pile on a thread made at its outer periphery. The stake has at its other end a warhead 6a; it also has inside a partition 6k which divides its internal volume into two parts to form two chambers 6m and 6c. Said partition 6c is located on the side of the warhead 6a and is constituted by a kind of ring fitted in the tube and fixed to the latter, for example by means of four cylindrical pins 6k _i , arranged in a cross and extending radially . Each pin is passed through an opening in the tube and through a reserved blind hole in the ring. The ring has in its center a duct of small section 61, which extends coaxially to the tube and is closed on the side of the chamber 6m by means of a cover 6j made of metal of low resistance, for example aluminum alloy .

Said cover is for example glued to the ring 6k. The 6m chamber is closed at its upper part located on the side of the pile head 10, by a shutter 35 which adopts the shape of a bou cylindrical cap threaded at its periphery and is screwed into the tube 6 which also has an internal thread. Said 6m chamber is filled with a synthetic resin polymerizable in contact with water.

The chamber 6c, which is of a smaller volume than the chamber 6m, contains an explosive charge 13 and its means of ignition: a micro-delay 44 and a primer 45 solicited at the time of the impact of the pile on the ground by means of a striker 6a _i fixed to the warhead 6a.

As the pile described with reference to FIG. 4, the pile 6 comprises, above the warhead 6a and in the walls of the chamber 6c, longitudinal grooves 6d constituting rupture lines to cause the deformation of the pile and thus ensure its anchoring. The space existing between the explosive charge 13 and the ring 6k is filled by three pellets 37/38/37 ₁ . The pads 37/37 ₁ are felt fillers, the pad 38 is made of expanded polystyrene.

For example, for an internal diameter of the pile of 16 mm, the wad 37 ₁ is 5 mm thick, the pellet 38 is 10 mm thick and the wad 37 is 15 mm thick. These pellets have the function of damping the shock wave in the chamber containing the synthetic resin 36 at the time of the explosion of the load 13 intended to cause the expansion of the pile.

The operating principle of the pile in this embodiment is to force the resin 36, initially trapped in the chamber 6m and as soon as the charge 13 explodes, to pass through the tears in the wall of the chamber 6c.

The gas overpressure created by the detonation of the charge 13 is partially recovered to eject the resin outside the pile. It is therefore necessary on the one hand to eliminate the impact effect in the direction of the pile head 10, this being obtained by means of the pads 37/38/37 ₁ ; on the other hand, it is necessary to decrease the speed of the gases resulting from the explosion of the charge 13. The reduction in the speed of the gases is obtained by means of the ring 6k which, placed between the explosive 13 and the filled chamber 6m resin, plays the role of a nozzle. The ring 6k, due to its central duct 61, which is of small section, makes it possible to vary the speed of the gases on either side of said ring and this in proportion to the sections brought into contact, on the principle that the mass flow of the gases from the explosion, is the same at the inlet and outlet of the conduit 61.

During the impact of the pile 6 on the ground, the warhead 6a, initiated via the primer 45 and the micro-delay 44, the charge of explosive 13. Part of the gas overpressure created by the explosion is thus used to force the resin 36 to flow outside the pile and around it in the cracks and cavities of the ground in order to increase, after hardening, the anchoring of the pile in the ground .

Reference is now made to FIG. 3 of the drawing which illustrates a device according to the invention in the "underwater" version.

In this figure, the members referenced 2, 4, 6, 8 and 10 are of the same design as those which have just been described with reference to Figures 1, 2 and 4.

As in the “terrestrial” device, the guide tube 16 comprises, at its upper part, an additional thickness 16a forming a shoulder bearing on the shoulder 2 _z a of the element 2 ₂ of the cylinder head 2. Said tube 16 comprises, at its lower end, a sleeve 17, which is for example screwed around the tube. The seal between the tube and the sleeve is ensured by an O-ring 18, engaged in a groove 17a formed at the internal periphery of the sleeve. This comprises a portion 17b of larger diameter which constitutes a base. This base comprises a conduit 17c extending perpendicular to the longitudinal axis of the sleeve and into which is screwed a valve 19 comprising a sealing plug 19a. The valve 19 partly occupies the conduit 17b. The sleeve 17 also has, at its lower end, a coaxial annular bearing 17d, which defines a shoulder 17e. This bearing 17d delimits a conical "inlet" 17f forming a housing intended to be occupied by a cover 20 which closes the guide tube 16 at its lower part.

This cover is made of sheet metal and forms a conical plug to cooperate closely with the housing 17f, which has a peripheral groove 17g in which is disposed a seal 21, for example an O-ring.

The apparatus having to be used at the bottom of the water, it is necessary that the internal volume of the guide tube in which the pile containing the cartridge 13 is placed, is perfectly dry.

The purpose of the valve 19 is to check the tightness of the guide tube 16 by creating a relative vacuum therein, for example of the order of 500 millibars.

The cover 20 is consumed during the firing.

The device is arranged on the ground while being supported on a base plate 22, for example circular, which comprises, in its center, an orifice of circular section 22a with a diameter greater than the outside diameter of the pile 6, to allow the passage of it. The plate 22 also comprises a centering housing 22b, coaxial with the orifice 22a, which is intended to receive the annular bearing surface 17d of the sleeve 17. The plate 22 also comprises points 22c or other similar members to promote its resistance to the ground in transverse direction, as well as mooring rings (not shown).

The reaction effect on the ground, at the time of firing in the aquatic environment, is contained by means of an anti-recoil car 23, fixed to the cylinder head 2. This car is for example produced in a metal plate and a circular configuration. Said plate extends, in one embodiment, in a plane perpendicular to the longitudinal axis of the device and is integral with a ferrule 23a which surrounds, with a slight play, the element 2 ₁ of the cylinder head 2. radial gussets 23b, of a triangular outline, ensure, by welding, the connection of the plate 23 and the ferrule 23a.

The anti-recoil wing is fixed to the cylinder head by means of several screws 24, for example four or six in number, passed through the plate and screwed into threads formed in the cylinder head.

The latter may include a centering shoulder 2 ₁ d of said plate, which has a central orifice for cooperating with said shoulder 2 ₁ d.

The assembly 17/16/2/8 and 23 is carried by a tripod 9, comprising a collar 9a on which the cylinder head 2 rests and telescopic feet 9b, with a device 9c for locking the sliding rod 9d. The feet 9b are pivotally mounted in yokes 9e to allow them to be put in an oblique position when installing the device in the firing position or to be folded down along the guide tube 16 when the device is out of use.

Referring now to Figures 5 to 9 of the drawing which relate to another embodiment of the invention based on the same operating principle of the devices which have just been described but which illustrate a device called "hammer-pestle to drive in threshing of anchor piles or coring tools.

The bodies 2/4/8/9/10/16/17/19/20 will not be described after the present description since they are substantially identical to those already described with reference to the previous figures.

In this embodiment, the tube 16 guides a cylindrical mass of steel 24. The latter has a diameter slightly smaller than the inside diameter of the guide tube 16 and has, at its upper part, a thread peripheral around which the head 10 is screwed with a shearable collar. This cylindrical mass 24 is hollowed out at its central part 24a, which is occupied by a material 25 of high density, for example lead, which has the function of increasing the mass.

The anti-recoil wing 26, which is fixed to the cylinder head 2, takes the form of a cone whose wall diverges from bottom to top. The wall 26a coming into contact with the cylinder head 2, has a circular opening making it possible to center the airfoil on the cylinder head, by cooperating with the shoulder 2 ₁ d. The wing is fixed to the cylinder head by means of screws 27, for example four or six, which pass through the wall 26a and which are screwed into tapped holes reserved in the cylinder head.

The conical side wall of the car is pierced with a plurality of small holes 26b distributed over its entire surface.

The conical shape of the wing aims, in addition to its function of anti-recoil device, to allow the axial descent of the device into the aquatic environment, which descent is further favored by the presence of the holes 26b through which the water circulates during lowering.

The pile to be beaten or the core tool is placed in the extension of the tube 16.

The drawing illustrates in FIG. 5 the device according to the invention in its application for inserting into the sea floor a coring tool 28.

In the claims, the term stake has been adopted to designate either a stake or a core tool.

The coring tool 28 is in the form of a tube and has, at its upper part, a head also called an "anvil" 29. This head has a constriction 29a, at its lower part, and is removable by being fitted in tube 28.

Its upper part is hollowed out to form an open cylindrical housing 29b in which is disposed, so as to occupy the entire section, a disc 30 of boxwood, compressed leather or any other similar material, intended to ensure the function of a damping member, which is surmounted by a metal disc 31, the function of which is to distribute the percussion force of the mass 24. The disc 31, which constitutes an independent moving part, is partially engaged in the housing 29b.

As shown in FIG. 5, the head 29 is applied, by means of the disks 30/31, against the cover 20 closing the guide tube 16 at its lower part and the guide tube 16, the mass 24 and stake 28 are coaxial.

Maintaining in this position is ensured by a cylindrical mount 32 which surrounds the guide tube and the pile, which mount has an internal diameter slightly greater than the external diameter of the sleeve 17, so that one can slide relative to the other.

At its lower part, the frame 32 preferably comprises four centering shims 32a, arranged in a cross (FIG. 8) and extending in opposition two by two inside the frame.

Said shims 32a are welded to the cylindrical shell of the frame and their free end is machined so that all of the shims define a circular "opening" 32b, coaxial with the shell and in which the pile 28 is engaged.

The pile thus centered with respect to the guide tube 16 is slidably mounted in the frame. This further comprises, at its upper part, another circular centering wedge 33 pierced in its center to receive the tube 16, which wedge is adjusted around the guide tube so as to be able to slide along the latter. The mount 32 has a conical "inlet" 32c. The wedge 33 is also conical so that it can be engaged in said inlet 32.

The pile 28 comprises, at its periphery, a continuous stop 28a, on which the stop, the mount is in abutment.

A tripod, not shown, of the kind illustrated in FIG. 3, freely encloses the pile 28 below said stop 28a.

Before firing, the device is placed in position on the tripod, the firing means 8 of the cartridge is armed, the mass 24 is put in place at the upper part of the guide tube 16, pressing on it by the shearable collar of the head 10. A relative vacuum is created in the tube 16 by connecting the valve 19 to a vacuum pump, the anvil 29 of the pile 28 is supported by the intermediate piece 31 against the cover 20 closing the tube 16.

As soon as the cartridge 5 is fired and the rupture of the collar 10a, the mass 24 is projected onto the side of the pile 28, which it ejects by percussion by striking the cover 20 and the intermediate disc 31.

The anvil 29 is separated from the tube and is recovered with the mass, the discs 30/31 and possibly the cover, in the frame 32.

The cover 20 can optionally be replaced for a new shot.

• Le volume de gaz créé du fait de la combustion de la poudre de la cartouche 5 est contraint dans la chambre d'expansion des gaz 4f et provoque dans cette chambre une élévation de pression. Lorsque cette pression atteint un seuil, elle exerce une force qui provoque le cisaillement de la collerette 10a de la tête 10, fixée au pieu 6 ou à la masse 24 et engagée dans le tube-guide 1/16, laquelle tête est en appui sur l'épaulement 1d situé au niveau de la partie 2₂ de la culasse 2, le tube-guide 1/16 constituant une chambre de détente des gaz. Le tube-guide 1/16 est ainsi comparable à un diffuseur dans lequel l'écoulement des gaz qui se produit entre la chambre 4f et le tube-guide 1/16, a lieu avec une perte négligeable. L'énergie cinétique des gaz est transformée presque totalement en pression dans le tube-guide dont le volume augmente au fur et à mesure de la progression du pieu 6. Cette détente des gaz supprime tout effet d'onde de choc à la sortie du tube-guide 1/16.

The operation of the device according to the invention is as follows:

• The volume of gas created by the combustion of the powder from the cartridge 5 is constrained in the gas expansion chamber 4f and causes in this chamber a rise in pressure. When this pressure reaches a threshold, it exerts a force which causes shearing of the flange 10a of the head 10, fixed to the pile 6 or to the mass 24 and engaged in the guide tube 1/16, which head is supported on the shoulder 1d located at the level of the part 2 ₂ of the cylinder head 2, the guide tube 1/16 constituting a gas expansion chamber. The guide tube 1/16 is thus comparable to a diffuser in which the flow of gases which occurs between the chamber 4f and the guide tube 1/16 takes place with negligible loss. The kinetic energy of the gases is almost completely transformed into pressure in the guide tube, the volume of which increases as the pile 6 progresses. This relaxation of the gases eliminates any shock wave effect at the outlet of the tube -guide 1/16.

Claims (20)

1. Pyrotechnical device for anchoring stakes or the like into the ground, comprising a stake (6, 28) and means of sinking said stake into the ground, which means comprise a breech (2) equipped with means (8) of firing a cartridge (5) and extended at its bottom part by a guide-tube (1/16) comprising, at its lower end, means of removing the air contained in the tube (1/16), characterized in that the tube (1/16) is designed to receive either a stake (6), or a movable mass (24) for hitting said stake (28) and in that said stake (6), which is introduced into the guide-tube (1/16) or the mass (24), is provided at its upper part with a head (10) which comprises shearable means of (10a) of holding said stake (6) or said mass (24) in position in the tube (1/16) before firing, so as to place the head (10) in resting contact against the breech (2), said breach comprising a housing (4a) for said cartridge (5), said housing being extended towards the part containing the head (10) by a gas-expanding chamber (4f), defined at its lower part by said head (10), said device further comprising means (4e/7) of improving tightness in the gas-expanding chamber (4f) at right angles with the junction of the head (10) with the breech (2), said chamber increasing in volume at firing time, as the stake or the mass (24) progresses into the guide-tube (1/16).

2. Device according to claim 1, characterized in that the head (10) of the stake (6) or of the mass (24) is provided on its periphery with a flange (10a) forming a shoulder in order to come to bear against a circular bearing surface (1d) provided in the breech (2), substantially level with the upper end of the guide-tube (1/16), said head (10) comprising, at the junction of the flange (10a) with the head body, an area of lesser resistance (10b) in order to obtain at firing, the separation by shearing of the flange (10a) and of the head body.

3. Device according to claim 2, characterized in that the head (10) comprises at least a groove (10c) extending at right angles with the area (10b) where the flange (10a) joins up with the head body, the depth of which groove (10c) is determined in relation to the volume of the gas-expanding chamber (4f).

4. Device according to claim 1, of which the breech (2) is produced in at least two parts (2₁/2₂) assembled one to other, characterized in that the housing (4a) for the cartridge (5) and the gas-expanding chamber (4f) are provided in a removable part (4), fitted in the centre of the breech (2) and co-axial to the guide-tube (1.16), which removable part (4) is, before firing, resting on said head (10).

5. Device according to claim 1, characterized in that the guide-tube (16) comprises, at its lower part, a sleeve (17) provided,. with an opening (17f) extending from the tube and co-axial thereto, said opening being closed off by a removable sealing plug (20) which is expelled at each firing, and in that the sleeve (17) comprises a valve (19) and means of connecting a vacuum apparatus in order to create a vacuum in the guide-tube (16) and to control its tightness before firing.

6. Device according to claim 5, provided at its upper part with a wing portion (23/26) forming a screen around the breech (2) in order to use the energy developed by the deflagrating charge at firing time, due to the recoil, characterized in that said wing portion (26) takes on the shape of a cone whose wall is diverging upwardly from the bottom, said wall comprising a plurality of orifices (26b) distributed on its periphery, in order to enable the device to sink into the aquatic medium according to a substantially vertical axis, before firing.

7. Device according to any one of claims 1 to 6, comprising a movable mass (24), characterized in that the stake (28) is before firing, extending from the guide-tube (16) inside which moves the lass (24), said stake (28) being in contact with the plug (20) sealing off the sleeve (17) situated at the bottom part of the guide-tube (16) via an independent movable part (31), said device comprising also means (32) of aligning, before firing, said tube (16) with said stake (28), and of guiding said stake during firing.

8. Device according to claim 7, characterized in that the alignment of the tube (16) with the stake (28) and it guiding are obtained by means of a frame (32) which surrounds the guide-tube (16) and the stake (28) and in that the sleeve (17) cooperates by its periphery with the side wall of said frame (32) which wall is co-axial to the tube (16) and to the stake (28), the lower part (32a) of said frame (32) forming a central opening (32b) which is traversed by the stake (28) and surrounds the latter with a slight play, as well as a centering wedge (33) sliding without play on the guide-tube (16) and closing off the frame (32) at its upper part, and in that said frame (32) rests against an abutment (28a) extending on the periphery of said stake (28).

9. Device according to any one of claims 7 and 8, characterized in that the mass (24) is in the form of a solid cylinder, of diameter slightly less than the inner diameter of the guide-tube (16), one end of which cylinder is threaded to receive the head (10) with its shearable flange (10a), which mass (24) is hollowed in its center (24a), the hollow part being occupied by a material of high density (25) in order to make it heavy.

10. Device according to any one of claims 7 to 9, characterized in that the head of the stake (29), which is still called anvil, is tightly fitted into the stake (28), is disconnectable therefrom and comprises, at its upper part, a cylindrical central housing (29b) which is co-axial to the stake (28) and to the guide-tube (16), in which housing is placed a damping disc (30) covering the bottom of the housing, which disc is topped by a metallic disc (31), centered by said housing (29b) by cooperating, by its peripheral edge, with the side wall of the housing (29b), said disc (31) being in contact with the plug (20).

11. Device according to any one of claims 1 to 4, characterized in that the stake head (10) is threaded and is screwed on the upper end of the stake (6) which is likewise threaded, so that the threading (6d) provided on the end of the stake, extends beneath the head of said stake (10) when said head comes flush with the upper part of the stake in order to perfect the anchoring of the stake (6) in the ground after firing, by screwing said head (10) on said stake (6).

12. Device according to any one of claims 10 or 11, characterized in that it comprises a ring (11) situated approximately at a third of the height of the stake from the bottom thereof, said ring projecting on the periphery of said stake to slide with slight play in the guide-tube (1/16), said ring (11) being produced from soft metal and being tightly screwed on the stake (6) to enable a relative movement between the ring (11) and the stake (6) at firing time and to act as a damping means at the moment when it is inserted between the head of the stake (10) and the ground, to absorb any excess of energy developed by the deflagrating charge.

13. Device according to claim 12, characterized in that the ring (11) adopts the shape of a « bobbin and comprises, at both ends, a peripheral bearing surface (11a) to reduce frictions and improve guiding of the stake (6) in the guide-tube (1/16).

14. Device according to any one of claims 10 to 13, which comprises at its lower part, a pointed end (6a), an exploding charge (13) placed inside a chamber (6c) provided in the axis of the stake, longitudinal grooves (6d) provided in the wall of said chamber (6c) to constitute breaking lines and means of firing the charge, said chamber being situated clearly above the pointed end (6a) so as to cause, when the charge is exploding, the breaking of the chamber wall (6c) along said lines (6d) and an outward deformation of the strips of metal which they define, with a view to causing a swelling of the stake in that area, to ensure its anchoring in the ground, characterized in that the stake (6) which is tubular, comprises, on the pointed end side, a ring-shaped wall (6k) provided with a central conduit (61) of small cross-section closed by a plug (6j) in low resistance metal, said ring being thus situated in the tube acting as a nozzle and defining, on one hand, between itself and the head of stake (10) a chamber (6m) closed at the level of the stake head (10) by a removable plug (35) ; said chamber (6m) contains a synthetic resin (36), and on the other hand, a chamber (6c) situated on y the pointed end side (6a) and containing the exploding charge (13) and the means of firing said charge which is separated from the ring by at least a wad of felt (37).

15. Device according to claim 14, characterized in that the exploding charge (13) is separated from the ring (6k) by at least one wad of felt (37) and by at least one patch (38) of expanded polystyrene.

16. Device according to any one of claims 14 and 15, which comprises at its lower part, a pointed end (6a), characterized in that it comprises on the one hand, on the side of the pointed end (6a) a wall (6p) constituted by a thin patch which defines a chamber (6q) containing a synthetic resin (39) and in front of which patch is placed a perforating member (6r) integral with the pointed end (6a) and disposed perpendicularly to the patch (6p) so as to perforate said patch when the stake meets with the ground due to the relative movement of the pointed end (6a) and of the stake and on the other hand, on the level of the stake head (10), a removable plug (40) closing the chamber (6q) at its upper part as well as means of putting the resin in contact with a pressurized fluid to expel the resin through openings (6s) provided on the periphery of the pointed end (6a).

17. Device according to claim 16, characterized in that it comprises at its upper part and in order to be protected by the plug (40), a wall (41) forming a valve support (42) for injecting into the chamber (6q) a charge of compressed gas (43) which is confined before firing in that part of chamber (6q) which is situated between the valve support (42) and the resin (39).

18. Device according to any one of claims 16/17, characterized in that the pointed end (6a) comprises a housing (6t) into which penetrates partly the end of the tubular part of the stake (6) which contains the patch (6p) until said patch is placed, before firing, close to the perforator (6r), the pointed end (6a) being secured to the stake by adhesive means in order to hold the patch (6p) and the perforator (6r) in that position.

19. Device according to claim 18, characterized in that the perforator (6r) is co-axial to the chamber (6q) and to the pointed end (6a) and adopts the shape of a tube cut in whistle manner at its end (Sr₁) facing the side of the patch (6p) and comprises orifices (6r₂) on its periphery to allow the resin to flow as soon as the stake penetrates into the ground after perforating the patch (6p).

20. Device according to any one of claims 16 to 19, characterized in that the pointed end (6a) comprises longitudinal grooves (6s) which issue into the housing (6t) as well as abutments (6x) to prevent close contact between the stake and the pointed end (6a) and allow the resin to flow through sa;d grooves (6s).

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