EP0533558A1 - Pincer grab excavator - Google Patents

Abstract

Excavator whose pincer grab is suspended from a square rod which is engaged in a guiding component of corresponding shape supported by a lifting machine via an articulation having a vertical axis, a driving device making it possible to pivot the guiding component about the said vertical axis, the rotation of the guiding component of the grab about its vertical axis being carried out in synchronism with the rotation of the mast of the lifting machine about its vertical axis so as to keep the grab in a constant direction. A computer or controller controls the synchronisation between the rotation of the mast (4) of the lifting machine (1) and the rotation of the guiding component (8), as well as the movements for raising or lowering the mast (4) of the lifting machine (1), means enabling the computer to store in memory information relating to the position of the grab (9) so as to allow the computer or controller to reproduce the movements of the grab (9) within a so-called safety zone in which the movements of the grab (9) are controlled by the computer or controller, whereas outside the safety zone, the operator is free to determine the movements of the mast (4) of the lifting machine (1) and of the grab (9). <IMAGE>

Description

The present invention relates to a clamshell excavation device making it possible to execute, under good conditions, trenches of relatively great depths in the immediate vicinity of pre-existing fixed obstacles.

There are already excavation devices known under the name of Kelly comprising a grab suspended from a square rod which engages in a guide piece of corresponding shape arranged for example at the top of the mast of a crane.

It is understood that in the present description, the term "square rod" designates, according to the terminology usual in this technique, a rod which can slide longitudinally in the guide piece, the sections of the rod and of the guide piece being such that the rod and the guide piece are secured in rotation about their longitudinal axis.

In a known variant, the buckets of these Kelly type devices can work at great depths, owing to the fact that their square rod is suspended from a cable and can thus be released from the guide part downwards.

The operation of these excavation devices requires special care when it is desired to carry out excavations in the immediate vicinity of pre-existing obstacles.

This is particularly the case when it is desired to produce walls molded into the ground which are located only a very short distance from the facades of buildings.

Indeed, the lifting device which supports the Kelly must execute a pivoting to empty the bucket in the excavation vehicle, and during this pivoting, it is necessary that the operator swivels the lifting device around of its vertical axis and in some cases that it raises the mast of the latter to avoid that during the rotation the bucket comes to strike the facade of the building along which the excavation is carried out.

Document FR-A-2 251 671 discloses a device making it possible to hold the bucket of a public works machine parallel to a given first direction when it is in a so-called loading area, and parallel to a given second direction when it is in a so-called unloading area.

However, such a device does not make it possible, under satisfactory safety conditions, to produce a trench near a building facade.

The present invention, on the contrary, makes it possible to dig a trench in the immediate vicinity of a pre-existing obstacle, such as a facade, in safe and economical conditions.

The subject of the present invention is an excavation apparatus, the clamshell of which is suspended from a square rod which engages in a guide part of corresponding shape supported by a lifting device by means of a joint with a vertical axis. , a motor device making it possible to pivot the guide piece around said vertical axis, the rotation of the bucket guide piece around its vertical axis being carried out in synchronism with the rotation of the mast of the lifting machine around its vertical axis so as to maintain the bucket in a constant direction, characterized in that a computer or an automaton manages the synchronization between the rotation of the mast of the lifting machine and the rotation of the guide piece, as well as the lifting or lowering movements of the mast of the lifting device, means enabling the computer to store information relating to the position of the bucket in order to allow the computer or the automaton to reproduce the movements of the bucket inside a so-called safety zone in which the movements of the bucket are controlled by the computer or the automaton, while outside the safety zone the operator is free to determine the movements of the mast of the hoist and of the bucket.

In a particular embodiment, the computer or the automaton is connected to an electronic means which counts pulses the number of which is proportional to the rotation of the mast of the lifting machine and causes, by means of a motor, for example hydraulic or electric, the rotation of the guide piece in the desired direction by an angle corresponding to the number of pulses recorded following the rotation of the mast of the lifting machine.

According to a preferred embodiment, the upper part of the guide piece is joined to the lifting device by a hydraulic rotary joint with vertical axis which ensures the supply of the bucket with hydraulic fluid while allowing the bucket to perform any number of rotations in one direction or the other.

In a more improved embodiment of the invention, the movements of raising or lowering of the bucket are also controlled by the computer or the automaton.

For the implementation of the apparatus according to the invention, the operator first places the bucket in the position and in the orientation which it must have to carry out the excavation, then, the computer or the automaton ensuring synchronism between the rotation of the hoist and that of the guide piece, the operator modifies the position of the mast of the hoist while the computer or the automaton stores at least some of the positions that have been given to the mast of the hoist by the operator.

From this information stored in memory, the computer or the automaton is then capable of reproducing with precision the movements of the mast of the lifting machine as well as the position of the bucket around its vertical axis.

The computer or the automaton can also manage the movements of the lifting machine as a function of the height at which the bucket is located so as to make any rotation movement of the lifting machine impossible as long as the bucket does not is not out of the excavation.

According to the invention, the kinematics of the bucket movements are thus imposed on the operator in a so-called "safety" zone which corresponds to that where untimely movements of the bucket could strike the obstacles close to the excavation.

According to the invention, an area is thus produced in which the kinematics of the movements of the bucket are totally controlled by the computer or the automaton, the operator being able in this area only to determine the dynamics, that is to say the speed with which the movements in question are executed.

Outside this safety zone, there is another so-called free zone in which the operator regains all his freedom to impose on the bucket the movements he wishes.

This free area is used in particular to empty the bucket in the cuttings transport vehicle.

In accordance with the invention, when the operator enters the safety zone by pivoting the lifting device, the computer or the automaton automatically places the bucket in the position it must have and which corresponds to the information that 'he has in memory.

According to a preferred variant of the invention, the computer or the automaton periodically rotates the bucket by 180 ° around its vertical axis so as to avoid that due to the asymmetry existing between the teeth of the two buckets it produce deviations in the excavation of the trench.

On the occasion of this 180 ° rotation, the computer or the automaton can advantageously tilt the reels which are used to store the hydraulic hoses of the bucket when the latter is in the high position towards the lifting machine. .

According to another improved embodiment of the invention, sensors are placed in various locations capable of supplying information to the computer or to the controller which takes this into account for controlling the bucket.

These sensors can be, for example, accelerometers or inclinometers, which make it possible to take account of the swing of the bucket when the lifting gear is pivoted. Inclinometers can also be used to ensure the verticality of the walls of the trench that is being constructed.

These sensors can also measure the weight of the cuttings in the bucket, thereby determining the inertia of the latter and the amplitude of the oscillations it undergoes as a function of the rotation speeds which are imposed on it.

Finally, sensors can be used to measure the forces that are necessary to close the bucket, which makes it possible to appreciate the nature of the ground that is encountered during excavation.

It can be seen that the invention makes it possible to provide automatic control of the movements of the bucket, which has the advantage of avoiding any risk of incident or operating accident and which makes it possible to significantly increase the speed of execution of the trench as well as the quality of this execution.

The present invention also relates to an excavation method using the apparatus described above, characterized in that a safety zone is defined in which the bucket is controlled to move parallel to a given direction and according to a given line; that the movement of the skip steered manually in this safety zone is stored in memory; and that during subsequent excavations the movement thus recorded is automatically reproduced from the skip in the safety zone, while the skip is freely piloted outside the safety zone in particular for its unloading.

Alternatively, the bucket is periodically rotated 180 ° around its vertical axis.

In order to better understand the invention will now be described by way of illustration and without any limiting character an embodiment taken as an example shown in the accompanying drawing.

• la figure 1 est une vue en élévation d'un mode de réalisation d'un appareil d'excavation selon l'invention, et
• la figure 2 est une vue schématique de dessus montrant diverses positions de la benne et du mât de l'engin de levage.

On this drawing :

• FIG. 1 is an elevation view of an embodiment of an excavation apparatus according to the invention, and
• Figure 2 is a schematic top view showing various positions of the bucket and the mast of the hoist.

Schematically shown in Figure 1 the lifting device 1 which is mounted on tracks 2 which can pivot about a vertical axis 3 relative to the latter.

The lifting device supports a mast 4 which, in the conventional manner, can be lowered or raised by pivoting around an axis located at its lower part.

The upper end of the mast supports the upper part 5 of the guide piece via a hinge pin 6.

This upper part 5 is joined by a hydraulic rotary joint 7 with a vertical axis to the actual guide part 8 inside which engages the square rod of the bucket 9. The reels 10 are also seen in FIG. 1 which allow hydraulic hoses to be stored when raising the bucket.

Finally, FIG. 1 shows the vertical axis 11 of the bucket and its guide piece 8. According to the invention, the rotation of the mast 4 of the lifting machine 1 around the axis 3 is synchronized by a computer or an automaton with the rotation of the bucket 9 and of the guide piece 8 around the vertical axis 11 so that, despite the rotation of the lifting device around the axis 3, the bucket 9 always moves parallel to itself. This synchronization can be achieved using different measuring means, for example electrical or electronic, emitting pulses proportional to the angle of rotation of the lifting device 1 around the axis 3, the computer or the automaton controlling the pivoting of the bucket 9 around the axis 11 through a motor hydraulic so as to rotate the bucket in proportion to the number of pulses received.

FIG. 2 represents a schematic top view of the excavation device shown in elevation in FIG. 1.

This is how we see the lifting machine 1 mounted on the tracks 2 with its mast 4 which supports the bucket 9 as previously indicated.

The facade 12 of a building has also been shown along which it is desired to make a trench 13.

The position of the bucket and of the lifting machine which supports it in the position where it excavates the trench 13, the two buckets of the bucket 9 being arranged, on either side of the mast 4.

The position of the lifting machine is shown in broken lines at the start of its movement for emptying the cuttings in the dump truck 14.

It can be seen in FIG. 2 that while the mast 4 ′ of the lifting machine has started to pivot to the right, the bucket 9 ′ has remained parallel to the trench 13, in accordance with the main characteristic of the invention.

A mixed line shows another position of the mast 4 m of the lifting machine and of the bucket 9˝ which remains parallel to the trench 13.

As explained above, in accordance with the invention, the synchronization between the rotation of the lifting device and the rotation of the bucket as well as the raising and lowering movements of the mast 4 are automatically ensured as long as the mast of the lifting machine remains in a so-called safety zone which has been schematically delimited in the drawing by the lines 15 and 16.

To this end, in a particular embodiment, the operator first of all stores in the memory of the computer or the automaton a certain number of parameters characterizing successive intermediate positions of the bucket 9 and the mast 4 during from their movement from the trench 13 to the dump truck 14.

From these recorded positions, the computer or the automaton reconstructs the continuous path of the bucket 9 and of the mast 4 by determining by interpolation the parameters corresponding to the non-recorded positions.

According to the invention, the lowering or raising movements of the mast 4 of the lifting device and the synchronization between the pivoting of the lifting device around the axis 3 and the pivoting of the bucket around axis 11 are provided by the computer or the automaton as long as the bucket moves in the so-called safety zone, yes in this case is between lines 15 and 16.

In this zone, the operator can only intervene on the speed of this movement and not on its trajectory.

On the other hand, outside the safety zone defined by lines 15 and 16, the operator is completely free to move the bucket as he pleases, which allows him to easily dump the spoil in the truck 14 stopped in an area which is free of obstacles.

We note that in the different positions of the mast 4.4 ′ and 4˝ located inside the safety zone, the bucket 9.9 ′ and 9˝ remains parallel to the trench by pivoting around its axis 11.11 ′ And 11˝.

By cons, outside the safety zone, the bucket 9′˝ can be placed in any position by the operator as well as the mast 4′˝ so as to allow the emptying of the bucket in the truck 14 .

It is understood that the embodiment which has been described above has no limiting nature and that it can receive any desirable modifications without departing from the scope of the invention.

Claims (8)

Excavation device whose grab is suspended from a square rod which engages in a guide piece of corresponding shape supported by a lifting device via a joint with a vertical axis, a motor device making it possible to make pivot the guide piece around said vertical axis, the rotation of the bucket guide piece around its vertical axis being carried out in synchronism with the rotation of the mast of the lifting machine about its vertical axis so as to maintain the bucket in a constant direction, characterized by the fact that a computer or an automaton manages the synchronization between the rotation of the mast (4) of the lifting machine (1) and the rotation of the guide piece (8), as well as the raising or lowering movements of the mast (4) of the lifting machine (1), means enabling the computer to store information concerning the position of the bucket (9) in order to allow the computer or the machine to reproduce the movements of the bucket (9) inside a so-called safety zone in which the movements of the bucket (9) are controlled by the computer or the automaton, while in outside the safety zone the operator is free to determine the movements of the mast (4) of the lifting machine (1) and of the bucket (9). Apparatus according to claim 1, characterized in that when the operator enters the bucket (9) into the safety zone, the computer or the automaton automatically returns the bucket (9) to the position in which it has put the characteristics in memory. Apparatus according to either of Claims 1 and 2, characterized in that the computer or the automaton is connected to an electronic means which counts pulses the number of which is proportional to the rotation of the mast (4) of the lifting device (1). Apparatus according to any one of claims 1 to 3, characterized in that the upper part of the guide piece (8) is joined to the lifting device (8) by a hydraulic rotary joint with vertical axis which ensures the 'supply of the bucket (9) with hydraulic fluid. Apparatus according to any one of claims 1 to 4, characterized in that the computer or the controller also controls the movements of raising or lowering of the bucket (9). Device according to any one of Claims 1 to 5, characterized in that the computer or the machine periodically rotates the bucket (9) by 180 ° around its vertical axis. Excavation method using an apparatus according to any one of Claims 1 to 6, characterized in that a safety zone is defined in which the bucket (9) is controlled to move parallel to a given direction and according to a given line; that the movement of the skip (9) manually controlled is recorded in this safety zone; and that the movement thus recorded of the bucket (9) is automatically reproduced in the safety zone; while the bucket (9) is freely piloted outside the safety zone, in particular for its unloading. Method according to claim 7, characterized in that the bucket (9) is pivoted periodically by 180 ° around its vertical axis.

Images