EP2147779B1 - Vibrating press for the production of construction elements and method for producing construction elements - Google Patents

Description

The present invention relates to a vibrating press for the production of building elements.

Vibrating presses are high-speed machines used in automatic production lines and in series of molded building elements such as blocks, pavers, interjoists, slabs, blocks, or curbs. The invention finds particular application in the production of building elements based on cement or concrete, and can be applied to other areas where we find the same problems of molding elements.

• une table vibrante équipée de plusieurs lignes de vibrateurs espacées les unes des autres et de moyens de contrôle de l'entraînement desdites lignes de vibrateurs,
• un moule disposé sur ladite table vibrante de sorte que les lignes de vibrateurs transmettent un mouvement de vibration audit moule, et
• un moyen de distribution qui permet d'alimenter le moule en produit frais à mouler, ledit moyen de distribution étant déplaçable au-dessus du moule entre une partie arrière et une partie avant du moule,

In a known embodiment, a vibrating press for the production of construction elements comprises:

• a vibrating table equipped with several rows of vibrators spaced from each other and control means for driving said lines of vibrators,
• a mold disposed on said vibrating table so that the vibrator lines transmit a vibration movement to said mold, and
• dispensing means for supplying the mold with fresh product to be molded, said dispensing means being movable above the mold between a rear part and a front part of the mold,

A vibrating press of this type is known in particular from the document EP 0 382 653 A1 .

The vibrating table conventionally comprises a thick metal plate under which are reported the lines of vibrators capable of generating a vibration force.

The mold is shaped to form the walls of the element to be molded, with means for holding the mold in abutment against a removable molding plate attached to the metal plate of the vibrating table. The mold, whose bottom or bottom is open, is placed directly on the molding plate. The mold, whose top is also open, is filled from above by the dispensing means.

The dispensing means generally consists of a drawer that moves linearly between a first position where a hopper drops fresh product into the drawer, and a second position above the mold where the product flows into the mold at as the drawer moves forward over the mold. The translation direction of the slide generally corresponds to the longitudinal direction of the vibrating press.

To compact the fresh product in the mold, the vibrating press also incorporates a compaction presser or pestle, vertically movable and optionally having a grid, being inserted into the interstices of the mold to form the hollow parts of the element to be molded.

It is also known to use vibrating presses, called double presses, comprising two vibrating tables, that is to say two independent tables provided with their own lines of vibrators. Such double presses have many disadvantages, the main one being that the central part of the mold straddles between the two tables and undergoes vibrations that are difficult to control. In the central part of the mold corresponding to the proximity zone of the two tables, there is generally a disordered tilting, that is to say a pivoting of the tables, which causes a non-homogeneous vibration over the entire surface of the mold causing thus filling variations on the central part of the mold which are detrimental to the final quality of the molded product.

• une phase de remplissage en produit frais du tiroir d'alimentation par une trémie ;
• une phase d'avancée du tiroir qui vient se déplacer linéairement au-dessus du moule afin de remplir ce dernier en produit frais, avec la table vibrante et ses lignes de vibrateurs qui entraînent en vibration la plaque de moulage pendant le remplissage du moule ;
• une phase de recul du tiroir qui retourne dans sa position de départ sous la trémie ;
• une phase de compactage par le presseur, avec la table vibrante et ses lignes de vibrateurs qui entraînent en vibration la plaque de moulage pendant le compactage ;
• une phase de démoulage de l'élément de construction sur la plaque de moulage en levant le moule, l'élément de construction étant maintenu sur la plaque de moulage notamment par le presseur ;
• phase d'évacuation de l'élément de construction, notamment à l'aide d'un convoyeur.

The production of building elements using a vibrating press comprises:

• a phase of filling fresh product of the feed drawer with a hopper;
• a phase of advancement of the drawer which moves linearly above the mold in order to fill it with fresh product, with the vibrating table and vibrator lines which cause the molding plate to vibrate during the filling of the mold;
• a recoil phase of the drawer which returns to its starting position under the hopper;
• a compression phase by the presser, with the vibrating table and vibrator lines which vibrate the molding plate during compaction;
• a demolding phase of the construction element on the molding plate by lifting the mold, the construction element being maintained on the molding plate in particular by the presser;
• evacuation phase of the building element, in particular using a conveyor.

At the end of molding, before the demolding phase, it is recommended to remove the vibration effect before removing the mold to prevent the freshly molded element from falling apart due to vibration.

The fresh product to be molded is preferably "dry" concrete, that is to say concrete in a pasty state and having sufficient rigidity to maintain a given shape after removal of the mold and when the freshly formed element rests only on the molding plate.

The application of a vibration to the concrete during the filling and compacting phases makes it possible to satisfy quality criteria of the construction elements thus produced. In particular, the elements must be of constant height, have a uniform and uniform compactness of the concrete, as well as a mechanical strength and a certain aspect.

The vibration, mainly unidirectional vertically and from below upwards, is transmitted by the vibrating table to the molding plate by means in particular of the vibrator lines and abutments of the bridge type known in particular from the document EP 1 875 996 A1 .

It is customary, as illustrated in the document EP 0 382 653 A1 , that the lines of vibrators consist of rotary vibrators feeder, formed of rotating shafts on which are mounted eccentric said weighted or unbalanced. The rotating shafts are aligned along horizontal axes and parallel to the direction of movement of the spool valve.

The weights are arranged at appropriate angles so that, when the vibrators are rotated in opposite directions of rotation and synchronously, they produce a substantially vertical unidirectional vibration force.

As a reminder, a vibration is a fast movement back and forth from a material point around its equilibrium position. In the case of rotary vibrators with flyweights, the vibratory movements originate from the centrifugal excitation forces created by the rotation of the flyweights.

• F est exprimée en N,
• m est la masse de la masselotte en kg,
• ω est la vitesse angulaire de la masselotte exprimée en rad/s, et
• R est la distance du centre de gravité de la masselotte par rapport à son axe de rotation exprimée en m.

The equation giving the value of the centrifugal force is the following: F = m.ω ² .R where

• F is expressed in N,
• m is the mass of the weight in kg,
• ω is the angular velocity of the flyweight expressed in rad / s, and
• R is the distance of the center of gravity of the weight relative to its axis of rotation expressed in m.

It is found that for a given weight having a defined shape, its mass and the position of its center of gravity are fixed. Only the variation of the rotational speed will vary the centrifugal force.

Thus, to obtain variable vibratory forces having controlled directions and intensities, it is necessary to ensure a combination of several rows of weights on the same vibrating table, with various orientations of the weights.

However, the direction of the vibration ensuring optimum efficiency is of the unidirectional and vertical type, it is necessary to analyze the projection of the vibratory force of each line of vibrators on both a vertical axis and a horizontal axis. The sum of the vertical projections will create the overall vibration motion. The sum of the horizontal projections should ideally vanish to prevent the movement of the vibrating table in the horizontal plane.

As rotating trees, the resulting force is variable with time, it is sinusoidal. The vibrating table therefore allows a vibration of given amplitude around a position of equilibrium.

In the filling phase of the mold and in the compaction phase, many parameters will influence the behavior of the fresh product and thus make the vibration more or less effective. These parameters include the weight of the mold, the dimensions and shape of the elements to be molded, the type of element to be molded using a suitable type of concrete, the quantity of concrete needed, the aggregates used in the fresh product.

During the advance phase of the feed drawer, the latter moves over the mold between a rear portion and a front portion of the mold, before starting its recoil phase. Thus, the rear part of the mold begins to fill by gravity while the front part will be only a few moments later. Indeed, the drawer first covers the rear portion of the mold and, progressively during its advance, moves the fresh product to the front part. Thus, the rear portion has been in a filling situation for a longer period of time than the front part.

As a result, the structural elements exiting the mold have a higher rearward density. Next, if the shape of the mold favors filling at the front, the reverse effect can also occur with a higher density towards the front of the building element.

This phenomenon of inhomogeneity is particularly present on double capacity presses for which the length of the molds is very important in the direction of advance of the feed drawer. The longer the mold is in the longitudinal direction of the press (corresponding to the direction of movement of the drawer) and the more the distribution of fresh product is shifted between the back and the front of the mold, and the less the density of the molded element is homogeneous in the longitudinal direction. The document EP 1 842 640 A discloses a vibrating press according to the preamble of claim 1 and a method according to the preamble of claim 13. The present invention is intended in particular to solve this drawback with a vibrating press adapted to promote or slow the filling of the mold fresh product on a rear or front part of the mold.

For this purpose, it proposes a vibrating press for the production of building elements having the characteristics of claim 1. The present invention therefore proposes to act on the vibration, and therefore on its lines of vibrators and on their control, to optimize the filling of the mold and avoid density dispersions.

Thus, the press according to the invention makes it possible to obtain a different force and vibration effect between the rear and the front of the mold (or between the rear and the front of the vibrating table on which the mold rests) only during the filling phase of the mold, and only if necessary.

Since the vibrator lines are transversely aligned relative to the direction of movement of the dispensing means (corresponding to the direction of filling of the mold), certain so-called rear lines extend mainly under the rear part of the mold, while certain other lines say before extend mainly under the front part. By controlling the training of the rear lines relative to the drive of the front lines, the press makes it possible to control the vibration between the back and the front of the mold in a simple and easy way.

According to the invention, the lines of vibrators each comprise a rotary shaft on which is mounted at least one eccentric of the unbalanced or flyweight type.

This type of vibrator line is also known as unbalanced vibrators.

Advantageously, the control means are designed to control the phase shift in the rotation of the rotary shafts, and corresponding eccentrics, in order to vary the vibrating force between the rear part and the front part of the mold.

Thus, because of the transverse orientation of the vibrator lines, the control means play on the phase shift of the eccentric rotation, between the rear lines and the front lines, to ensure a different vibration force between the rear and the rear. 'before the mold.

• une paire arrière disposée sous la partie arrière du moule et comprenant un premier et un deuxième arbres rotatifs, et
• une paire avant disposée sous la partie avant du moule et comprenant un troisième et un quatrième arbres rotatifs.

According to one characteristic, the press comprises at least two pairs of vibrator lines, of which:

• a rear pair disposed beneath the rear portion of the mold and including first and second rotating shafts, and
• a front pair disposed under the front portion of the mold and including a third and a fourth rotating shafts.

• le sens et la vitesse de rotation des quatre arbres, et
• le déphasage relatif dans la rotation de chacun desdits quatre arbres, équivalent à l'inclinaison respective du ou des excentriques desdits arbres relativement à une direction principale,

afin que la composante verticale de la force centrifuge résultant de la rotation des premier et deuxième arbres soit distincte de la composante verticale de la force centrifuge résultant de la rotation des troisième et quatrième arbres.The control means can thus be designed to control:

• the direction and speed of rotation of the four trees, and
• the relative phase shift in the rotation of each of said four shafts, equivalent to the respective inclination of the eccentric or eccentric of said shafts relative to a main direction,

so that the vertical component of the centrifugal force resulting from the rotation of the first and second shafts is distinct from the vertical component of the centrifugal force resulting from the rotation of the third and fourth shafts.

Thus, by varying the different rotation parameters of the four shafts, the invention makes it possible to give priority to the vibration at the rear or the front of the mold in order to compensate for the filling defects inherent in the feed means by a displacement at above the mold.

Such a press may nevertheless lead to the existence of a horizontal vibratory component, or horizontal component of the force centrifugal, which is still low intensity and therefore no adverse effect on the entire press and on the building elements.

• orienter le ou les excentriques du premier arbre selon une direction principale (par exemple la direction verticale) et dans un premier sens (par exemple vers le haut), et orienter le ou les excentriques du deuxième arbre selon la même direction principale et dans un deuxième sens (par exemple vers le bas) opposé au premier sens,
• orienter le ou les excentriques du troisième arbre selon la même direction principale et dans le deuxième sens, et orienter le ou les excentriques du quatrième arbre selon la même direction principale et dans le premier sens,
• déphaser le premier arbre d'un premier angle dans un premier sens de rotation (par exemple le sens antihoraire) et déphaser le deuxième arbre du même premier angle dans le même premier sens de rotation,
• déphaser le troisième arbre d'un deuxième angle, distinct du premier angle, dans un deuxième sens de rotation (par exemple le sens horaire) opposé au premier sens de rotation, et déphaser le quatrième arbre du même deuxième angle dans le même deuxième sens de rotation, et ensuite
• permettre la rotation des premier, deuxième, troisième et quatrième arbres à la même vitesse et de façon synchrone,
• assurer que les premier et troisième arbres tournent selon le deuxième sens de rotation,
• assurer que les deuxième et quatrième arbres tournent selon le premier sens de rotation,

afin que le mouvement de vibration transmis par les lignes de vibrateurs au moule soit distinct entre la partie arrière et la partie avant du moule.In a preferred embodiment, the control means are designed to:

• orienting the eccentric (s) of the first shaft in a main direction (for example the vertical direction) and in a first direction (for example upwards), and orienting the eccentric (s) of the second shaft in the same main direction and in a second direction meaning (for example downwards) opposite to the first direction,
• orienting the eccentric or eccentrics of the third shaft in the same main direction and in the second direction, and orienting the eccentric or eccentrics of the fourth shaft in the same main direction and in the first direction,
• shifting the first shaft by a first angle in a first direction of rotation (for example counterclockwise) and shifting the second shaft by the same first angle in the same first direction of rotation,
• phase shifting the third shaft by a second angle, distinct from the first angle, in a second direction of rotation (for example the clockwise direction) opposite the first direction of rotation, and phase shifting the fourth shaft of the same second angle in the same second direction of rotation, and then
• allow rotation of the first, second, third and fourth trees at the same speed and synchronously,
• ensure that the first and third shafts rotate in the second direction of rotation,
• ensure that the second and fourth shafts rotate in the first direction of rotation,

so that the vibration movement transmitted by the vibrator lines to the mold is distinct between the rear portion and the front portion of the mold.

In addition, the control means are adapted to also allow the vibration movement transmitted by the vibrator lines to said mold to be identical between the rear part and the front part of the mold.

Thus, in the case of a filling where there is no problem of distribution of the fresh product (due to the shape of the mold or the fresh product itself), or in the case of the compaction phase that follows the phase When filling the mold, the press is adapted to print an identical vibration force between the back and the front of the mold.

• le sens et la vitesse de rotation des quatre arbres définis ci-dessus, et
• le déphasage relatif dans la rotation de chacun desdits quatre arbres, équivalent à l'inclinaison respective du ou des excentriques desdits arbres relativement à une direction principale,

afin que la composante verticale de la force centrifuge résultant de la rotation des premier et deuxième arbres soit égale à la composante verticale de la force centrifuge résultant de la rotation des troisième et quatrième arbres.In this case, the control means are also designed to control:

• the direction and speed of rotation of the four trees defined above, and
• the relative phase shift in the rotation of each of said four shafts, equivalent to the respective inclination of the eccentric or eccentric of said shafts relative to a main direction,

so that the vertical component of the centrifugal force resulting from the rotation of the first and second shafts is equal to the vertical component of the centrifugal force resulting from the rotation of the third and fourth shafts.

• orienter le ou les excentriques des premier, deuxième, troisième et quatrième arbres selon une même direction principale et dans un même sens,

et ensuite

• permettre la rotation des premier, deuxième, troisième et quatrième arbres à la même vitesse et de façon synchrone,
• assurer que les premier et troisième arbres tournent selon le deuxième sens de rotation,
• assurer que les deuxième et quatrième arbres tournent selon le premier sens de rotation opposé au deuxième sens de rotation.

afin que le mouvement de vibration transmis par les lignes de vibrateurs au moule soit identique entre la partie arrière et la partie avant du moule.In a preferred embodiment, the control means are designed to:

• orient the eccentric (s) of the first, second, third and fourth trees in the same main direction and in the same direction,

and then

• allow rotation of the first, second, third and fourth trees at the same speed and synchronously,
• ensure that the first and third shafts rotate in the second direction of rotation,
• ensure that the second and fourth shafts rotate in the first direction of rotation opposite the second direction of rotation.

so that the vibration movement transmitted by the vibrator lines to the mold is the same between the rear part and the front part of the mold.

According to one characteristic, the rotary shafts support several eccentric oriented in the same direction and the same direction.

According to one characteristic, the dispensing means is movable in translation along a longitudinal axis of the press, and the vibrator lines extend along a transverse axis of the press substantially normal to said longitudinal axis.

Preferably, the press is of the type comprising a single vibrating table. Thus, the particular orientation of the vibrator lines under this single vibrating table makes it possible to control and make the vibrating force between the front and the rear of this table to obtain amplitudes, speeds and accelerations applied to this different table between the front and back. This makes it possible to correct or compensate, if necessary, the filling in fresh product to be molded between the front and the back and thus obtain a homogeneous filling.

The present invention also relates to a method for producing building elements comprising the steps of claim 13. For the following, the vibrator lines each comprise a rotary shaft on which is mounted at least one eccentric of the unbalance type or flyweight, and the press comprises at least two pairs of vibrator lines, including a rear pair disposed under the rear portion of the mold and including first and second rotary shafts, and a front pair disposed under the front portion of the mold and comprising a third and a fourth rotary shafts.

• le sens et la vitesse de rotation des quatre arbres, et
• le déphasage relatif dans la rotation de chacun desdits quatre arbres, équivalent à l'inclinaison respective du ou des excentriques desdits arbres relativement à une direction principale,

afin que la composante verticale de la force centrifuge résultant de la rotation des premier et deuxième arbres soit distincte de la composante verticale de la force centrifuge résultant de la rotation des troisième et quatrième arbres.In this case, the control of the rotary drive of the vibrator lines may consist of controlling:

• the direction and speed of rotation of the four trees, and
• the relative phase shift in the rotation of each of said four shafts, equivalent to the respective inclination of the eccentric or eccentric of said shafts relative to a main direction,

so that the vertical component of the centrifugal force resulting from the rotation of the first and second shafts is distinct from the vertical component of the centrifugal force resulting from the rotation of the third and fourth shafts.

• orienter le ou les excentriques du premier arbre selon une direction principale et dans un premier sens, et orienter le ou les excentriques du deuxième arbre selon la même direction principale et dans un deuxième sens opposé au premier sens,
• orienter le ou les excentriques du troisième arbre selon la même direction principale et dans le deuxième sens, et orienter le ou les excentriques du quatrième arbre selon la même direction principale et dans le premier sens,
• déphaser le premier arbre d'un premier angle dans un premier sens de rotation et déphaser le deuxième arbre du même premier angle dans le même premier sens de rotation,
• déphaser le troisième arbre d'un deuxième angle, distinct du premier angle, dans un deuxième sens de rotation opposé au premier sens de rotation, et déphaser le quatrième arbre du même deuxième angle dans le même deuxième sens de rotation,

et ensuite

• permettre la rotation des premier, deuxième, troisième et quatrième arbres à la même vitesse et de façon synchrone,
• assurer que les premier et troisième arbres tournent selon le deuxième sens de rotation,
• assurer que les deuxième et quatrième arbres tournent selon le premier sens de rotation.

In order that the vibration movement transmitted by the lines of vibrators to the mold is distinct between the rear part and the front part of the mold, the control of the rotational drive can comprise the following steps:

• orienting the eccentric (s) of the first shaft in a main direction and in a first direction, and orienting the eccentric (s) of the second shaft in the same main direction and in a second direction opposite to the first direction,
• orienting the eccentric or eccentrics of the third shaft in the same main direction and in the second direction, and orienting the eccentric or eccentrics of the fourth shaft in the same main direction and in the first direction,
• shifting the first shaft by a first angle in a first direction of rotation and shifting the second shaft of the same first angle in the same first direction of rotation,
• shifting the third shaft by a second angle, distinct from the first angle, in a second direction of rotation opposite the first direction of rotation, and phase shifting the fourth shaft of the same second angle in the same second direction of rotation,

and then

• allow rotation of the first, second, third and fourth trees at the same speed and synchronously,
• ensure that the first and third shafts rotate in the second direction of rotation,
• ensure that the second and fourth shafts rotate in the first direction of rotation.

In addition, the method comprises a step of compacting the product to be molded with a step of controlling the rotation drive of the vibrator lines adapted to allow the vibration movement transmitted by the vibrator lines to said mold to be identical between the part back and the front part of the mold during compaction.

• le sens et la vitesse de rotation des quatre arbres définis ci-dessus, et
• le déphasage relatif dans la rotation de chacun desdits quatre arbres, équivalent à l'inclinaison respective du ou des excentriques desdits arbres relativement à une direction principale,

afin que la composante verticale de la force centrifuge résultant de la rotation des premier et deuxième arbres soit égale à la composante verticale de la force centrifuge résultant de la rotation des troisième et quatrième arbres.During the compacting step, the control of the rotary drive of the vibrator lines may consist in controlling:

• the direction and speed of rotation of the four trees defined above, and
• the relative phase shift in the rotation of each of said four shafts, equivalent to the respective inclination of the eccentric or eccentric of said shafts relative to a main direction,

so that the vertical component of the centrifugal force resulting from the rotation of the first and second shafts is equal to the vertical component of the centrifugal force resulting from the rotation of the third and fourth shafts.

• orienter le ou les excentriques des premier, deuxième, troisième et quatrième arbres selon une même direction principale et dans un même sens,

et ensuite

• permettre la rotation des premier, deuxième, troisième et quatrième arbres à la même vitesse et de façon synchrone,
• assurer que les premier et troisième arbres tournent selon le deuxième sens de rotation,
• assurer que les deuxième et quatrième arbres tournent selon le premier sens de rotation opposé au premier sens de rotation.

In order that the vibration movement transmitted by the vibrator lines to the mold is the same between the rear part and the front part of the mold during the compaction stage, the control of the rotational drive can comprise the following steps:

• orient the eccentric (s) of the first, second, third and fourth trees in the same main direction and in the same direction,

and then

• allow rotation of the first, second, third and fourth trees at the same speed and synchronously,
• ensure that the first and third shafts rotate in the second direction of rotation,
• ensure that the second and fourth shafts rotate in the first direction of rotation opposite the first direction of rotation.

• la figure 1 est une vue de côté d'une partie d'une presse vibrante conforme à l'invention, dans une phase de remplissage en produit frais d'un tiroir d'alimentation ;
• la figure 2 est une vue de côté d'une partie de la presse vibrante illustrée en figure 1, dans une phase de remplissage en produit frais d'un moule au moyen du tiroir d'alimentation ;
• la figure 3 est une vue en perspective de la presse vibrante illustrée aux figures 1 et 2, montrant plus particulièrement les lignes de vibrateurs ;
• la figure 4 est une vue schématisée de côté des lignes de vibrateurs illustrant deux étapes d'un premier cycle de contrôle de l'entraînement en rotation des lignes de vibrateurs ;
• la figure 5 est une vue schématisée de côté des lignes de vibrateurs illustrant deux étapes d'un deuxième cycle de contrôle de l'entraînement en rotation des lignes de vibrateurs ;
• la figure 6 est une vue schématisée de côté des lignes de vibrateurs illustrant trois étapes d'un troisième cycle de contrôle de l'entraînement en rotation des lignes de vibrateurs ;

Other features and advantages of the present invention will appear on reading the detailed description below, of an example of non-limiting implementation, with reference to the appended figures in which:

• the figure 1 is a side view of a portion of a vibrating press according to the invention, in a fresh product filling phase of a feed drawer;
• the figure 2 is a side view of a portion of the vibrating press illustrated in figure 1 in a fresh product filling phase of a mold by means of the feed drawer;
• the figure 3 is a perspective view of the vibrating press illustrated in figures 1 and 2 , showing more particularly the lines of vibrators;
• the figure 4 is a schematic side view of the vibrator lines illustrating two steps of a first control cycle of the rotational drive of the vibrator lines;
• the figure 5 is a schematic side view of the vibrator lines illustrating two steps of a second control cycle of the rotary drive of the vibrator lines;
• the figure 6 is a schematic side view of the vibrator lines illustrating three steps of a third control cycle of the rotary drive of the vibrator lines;

• un châssis 1 ;
• une table vibrante 2 unique comportant une plaque 20 sous laquelle sont fixés des lignes de vibrateurs 5 ;
• un moule 3 posé sur la table vibrante 2 par l'intermédiaire d'une plaque de moulage 30 ;
• un tiroir de distribution 4 pour remplir le moule 3 en produit frais à mouler ; et
• un presseur ou pilon non représenté sur les figures et destiné à compacter le produit frais dans le moule et à pénétrer dans le moule 3 pour permettre d'en extraire les éléments de construction formés sur la plaque de moulage 30.

According to an embodiment shown on the Figures 1 to 3 a vibrating press according to the invention for the production of construction elements comprises:

• a chassis 1;
• a single vibrating table 2 comprising a plate 20 under which are fixed lines of vibrators 5;
• a mold 3 placed on the vibrating table 2 by means of a molding plate 30;
• a dispensing spool 4 for filling the mold 3 with fresh product to be molded; and
• a pressure or pestle not shown in the figures and intended to compact the fresh product in the mold and to enter the mold 3 to allow the extraction of the construction elements formed on the molding plate 30.

In the reference (X, Y, Z), illustrated in different figures, the axis X indicates the longitudinal direction of the press, and the axis Y indicates the transverse direction of the press, where the two axes X and Y are perpendicular. and horizontal. As for the Z axis, it indicates the vertical direction, from bottom to top, of the press.

In addition, the fresh product considered in the remainder of the application is concrete, although the use of other fresh products is clearly conceivable for a press according to the invention.

The frame 1 consists of a fixed frame anchored to the ground and comprising in particular horizontal and transverse beams 10 on which the vibrating table 2 rests, via elastic suspension studs 21, and vertical beams 11 fixed in the ground. The frame 1 further comprises horizontal and longitudinal beams 12 extending under the distribution slide 4, and intended to support conveying means of the molding plates 30.

• la plaque 20, formée d'une tôle épaisse en acier, et reposant sur les poutres horizontales et transversales 10 du châssis 1 par l'intermédiaire des plots de suspension élastique 21,
• des lignes de vibrateurs 5 du type vibrateur à balourd, comportant des arbres rotatifs 51, 52, 53, 54 sur lesquels sont montés des excentriques 55 générant une force centrifuge, du type balourd ou masselotte, et des moteurs 56 d'entraînement en rotation des lignes de vibrateurs 5 autrement dit des arbres 51, 52, 53, 54 ;
• un ensemble de parois d'appui verticales (non illustrées) parallèles fixées au dessus de la plaque 20, le bord supérieur de ces parois définissant la surface d'appui supérieure de la table vibrante 2.

The vibrating table 2 comprising:

• the plate 20, formed of a thick sheet of steel, and resting on the horizontal and transverse beams 10 of the frame 1 by means of the elastic suspension studs 21,
• vibrator lines 5 of the unbalanced vibrator type, comprising rotary shafts 51, 52, 53, 54 on which are mounted eccentrics 55 generating a centrifugal force, of the unbalanced or flyweight type, and motors 56 for driving in rotation of vibrator lines 5, in other words, shafts 51, 52, 53, 54;
• a set of parallel support walls (not shown) parallel fixed above the plate 20, the upper edge of these walls defining the upper bearing surface of the vibrating table 2.

The vertical support walls, also called wear plates or candles, comprise at least one removable portion so that it can be replaced when worn.

The vibrating table 2 thus has an upper bearing surface, on which is intended to be placed the molding plate 30 forming support of the mold 3 and the associated eccentric building element.

The press comprises bridges (not shown) integral with the frame, constituting an abutment limiting the downward movement of the molding plate 30 placed on the vibrating table 2 under the action of a pressure exerted on the mold 3. A trigger guard , otherwise referred to as a fixed lower abutment, is generally in the form of a horizontal bar extending across the vibrating table 2, above the plate 20, and between the abutment walls. At these two ends, this bridge bar is fixed on vertical uprights, especially by means of shims whose thickness to adjust the relative position of the upper surface of the bridges relative to the upper bearing surface of the 2. The vertical uprights typically rest on a rigid frame located under the horizontal and transverse beams 10 of the frame 1.

With regard to the vertical support walls and the bridges, the present application refers in particular to the EP 1 875 996 A1 and EP 0 382 653 A1 for additional details; the subject of the present application relates more specifically to the lines of vibrators 5 and their rotational drives.

• une première position, illustrée en figure 1, où le tiroir 4 est disposé sous une trémie (non représentée) qui laisse tomber du béton frais dans le tiroir 4, et où le tiroir 4 est disposé sur une plaque de retenue 14 solidaire du châssis 1, ladite plaque de retenue s'étendant horizontalement jusqu'au rebord arrière du moule 3 afin de retenir le béton dans le tiroir 4, et
• une deuxième position, illustrée en figure 2, où le tiroir 4 est disposée au-dessus du moule 3, à la vertical de ce dernier, afin que le béton s'écoule par gravité dans le moule 3.

The distribution drawer 4 forms a box, open at the top and bottom, delimited by a vertical partition. This drawer 4 moves longitudinally, that is to say in the direction X, to bring fresh concrete into the mold 3 from a reserve silo; the displacement of the drawer 4 being illustrated by the arrow D to figures 1 and 3 . For this, the dispensing spool 4 is movable between:

• a first position, illustrated in figure 1 , where the drawer 4 is arranged under a hopper (not shown) which drops fresh concrete in the drawer 4, and where the drawer 4 is disposed on a retaining plate 14 secured to the frame 1, said retaining plate extending horizontally to the rear edge of the mold 3 to hold the concrete in the drawer 4, and
• a second position, illustrated in figure 2 , where the drawer 4 is disposed above the mold 3, to the vertical of the latter, so that the concrete flows by gravity into the mold 3.

The retaining plate 14 is a horizontal plate extending to the rear rim 31 of the mold 3; the rear of the mold 3 being defined as the portion of the mold 3 upstream relative to the direction of movement of the slide 4 from the first to the second position, corresponding to the right portion on the figures 1 and 2 .

During its advance to fill the mold 3, to the left on the figures 1 and 2 , the drawer 4 does not empty until it has passed the retaining plate 14. Then, once the drawer 4 exceeds the retaining plate 14, the concrete 3 begins to flow into the mold 3 , and more particularly at the rear of the mold 3, until the drawer 4 reaches the second position where it covers at least completely the top of the mold 3, and in particular the front of the mold 3, and completely fills said mold 3.

The mold 3 is shaped to form the walls of the element to be molded. The mold 3, whose bottom or bottom is open, is placed directly on the molding plate 30. The mold 3, whose top is also open, is filled from above, as already described, by the dispensing spool 4. The mold 3 has a rear portion 32 and a front portion 33.

To have a different vibration movement between the rear portion 32 and the front portion 33 of the mold 3, the vibrator lines 5 extend in the transverse direction Y, perpendicular to the longitudinal direction X corresponding to the direction of movement of the drawer 4 , and comprise lines arranged under the rear portion 32, dedicated mainly to the vibration of this rear portion 32, and lines disposed under the front portion 33, dedicated primarily to the vibration of this front portion 33.

• une paire arrière disposée sous la partie arrière 32 du moule 3 et comprenant un premier 51 et un deuxième 52 arbres rotatifs, et
• une paire avant disposée sous la partie avant 33 du moule et comprenant un troisième 53 et un quatrième 54 arbres rotatifs.

In particular, the vibratory lines 5 are four in number, with two pairs of lines of vibrators 5, of which:

• a rear pair disposed under the rear portion 32 of the mold 3 and comprising a first 51 and a second 52 rotating shafts, and
• a front pair disposed under the front portion 33 of the mold and comprising a third 53 and a fourth 54 rotating shafts.

The lines of vibrators 5 are parallel to each other, all the shafts 51 to 54 all extending parallel to the transverse axis Y. The eccentrics 55 of the different shafts are all identical, of the same mass and of the same shape. The lines of vibrators 5 are identical to each other and are regularly offset relative to each other in the longitudinal direction X. On the same shaft, all the eccentrics 55 are oriented in the same direction and the same direction; the eccentrics 55 being integral in rotation with their respective shafts, these eccentrics will remain similarly aligned on their shafts during all phases of life of the vibrating press.

As illustrated in figure 3 each shaft is associated with a motor 56 for driving in rotation. The motors 56 are arranged along a horizontal and longitudinal beam 12 in which are provided passage zones for traversing the shafts 51 to 54.

The shafts 51 to 54 are supported by bearings 57 consisting of two longitudinal housings comprising bearings lubricated by bubbling in an oil bath and fixed rigidly under the plate 20 of the vibrating table 2, in particular by means of fixing screws.

The shafts 51 to 54 comprise several sections interconnected by transmissions 58, in particular a cardan joint disposed linking two shaft sections between the two bearings 57. Of course, the invention is not limited to the shape of the shafts. rotary, nor those of the bearings 57 or transmissions 58 in case of cut-off tree.

Intermediate housings 60 may each receive two independent shafts mounted on bearings lubricated by an oil bath; the role of these intermediate boxes 60 is to create intermediate bearings receiving jerks retransmitted by the transmissions driving the shafts of vibrators.

Each shaft 51 to 54 is further connected to a motor 56 by means of transmissions 59 sliding with universal joints connecting the outgoing shaft sections of these housings 60 to the shaft sections located under the vibrating table 2.

The four motors 56 are electric and each equipped with an electronic system for angular position control, in particular of the resolver or encoder type. Each motor 56 is powered by a frequency converter equipped with an electronic positioning card. The frequency converter makes it possible to choose the speed of rotation of the motor 56 and thus of the lines 5 or of the shafts 51 to 54 carrying the eccentrics 55. The positioning cards are associated with a main control member of the press according to the invention. and, in particular through a specially adapted program, will manage and control the angular position of each of the motors 56 and therefore of each of the lines 5 or shafts 51 to 54.Each motor 56 being angularly managed independently, it will it is possible to combine them differently to allow a distinct vibration movement between the back and the front of the mold 3.

With a vibrating press according to the invention, several vibration movements are possible by adjusting the phase shift or not of the different shafts 51 to 54.

For the following description and although it is a single vibrating table 2, the rear pair of vibrator lines 5, consisting of the first 51 and second 52 trees, is supposed to act mainly on the rear portion 32 of the mold 3, while the front pair of vibratory lines 5, consisting of the third 53 and fourth 54 shafts, is supposed to act mainly on the front portion 33 of the mold 3.

• le premier arbre 51 tourne dans le sens positif (correspondant au sens horaire sur les figures 4 à 6) tandis que le deuxième arbre 52 tourne dans le sens négatif (correspondant au sens antihoraire sur les figures 4 à 6) ; et
• le troisième arbre 53 tourne dans le sens positif tandis que le quatrième arbre 54 tourne dans le sens négatif.

Inside each pair of vibrator lines, respectively rear and front, the shafts rotate in opposite directions, in this case:

• the first shaft 51 rotates in the positive direction (corresponding to the clockwise direction on the Figures 4 to 6 ) while the second shaft 52 rotates in the negative direction (corresponding to the counterclockwise direction on the Figures 4 to 6 ); and
• the third shaft 53 rotates in the positive direction while the fourth shaft 54 rotates in the negative direction.

On the figure 4 there is shown a first control cycle of the rotary drive of the lines of vibrators 5, where the shafts of the same pair of vibrator lines, respectively rear and front, are at first t = 0 opposite one to the other.

In other words, at the initial time t = 0 of the first cycle, the eccentrics of the first shaft 51 are opposed to the eccentrics of the second shaft 52, that is to say that they are all aligned in the same vertical direction Z but in opposite directions; the eccentrics of the first shaft 51 pointing upwards while the eccentrics of the second shaft 52 point downwards. Similarly, at the initial time t = 0 of the first cycle, the eccentrics of the third shaft 53 are opposed to the eccentrics of the fourth shaft 54, that is to say that they are all aligned in the same vertical direction Z but in opposite directions; the eccentrics of the third shaft 53 pointing downwards while the eccentrics of the fourth shaft 54 point upwards.

Then, the shafts 51 to 54 are all rotated at the same speed ω and synchronously in opposite directions within each pair of vibrator lines (as already mentioned), so that the different centrifugal forces F1 to F4 from the rotation of the respective shafts 51 to 54 cancel each other out.

In conclusion, during this first cycle, when the eccentrics are in pairs opposite to the other two, they rotate at the same speed, whatever the speed of rotation, the vertical projections of the components of the vibratory force F1 to F4 of each shaft line 51 to 54 oppose. Finally, we obtain a resultant zero force and therefore no vibration movement at the vibrating table 2.

On the figure 5 there is shown a second cycle of control of the rotation drive of the lines of vibrators 5, where all the trees are at first t = 0 aligned in the same direction and in the same direction. In other words, at the initial time t = 0 of the second cycle, the eccentrics of the shafts 51 to 54 are all aligned in the same vertical direction Z and the same direction; the eccentrics of the trees 51 to 54 all point upward on the figure 5 at the instant t = 0.

• les composantes verticales, en Z, des forces centrifuges F1 à F4 issues de la rotation des arbres 51 à 54 respectifs sont égales avec
  • F1z = F2z = F3z = F4z = F.cos (ωt) où pour rappel F = m.ω².R pour les arbres 51 à 54 dont les excentriques sont tous identiques ; et
• les composantes horizontales, en X, de ces mêmes forces centrifuges F1 à F4 s'annulent avec $$\mathrm{F}1\mathrm{x}=-\mathrm{F}2\mathrm{x}=\mathrm{F}3\mathrm{x}=-\mathrm{F}4\mathrm{x}.$$
  

Then, the shafts 51 to 54 are all rotated, at the same speed ω and synchronously, in opposite directions within each pair of vibrator lines (as already mentioned), so that:

• the vertical components, in Z, of the centrifugal forces F1 to F4 resulting from the rotation of the respective shafts 51 to 54 are equal to
  • F1z = F2z = F3z = F4z = F.cos (ωt) where for return F = m.ω ² .R for the shafts 51 to 54 whose eccentrics are all identical; and
• the horizontal components, in X, of these same centrifugal forces F1 to F4 are canceled with $$\mathrm{F}1\mathrm{x}=-\mathrm{F}2\mathrm{x}=\mathrm{F}3\mathrm{x}=-\mathrm{F}4\mathrm{x}.$$
  

Thus, the vertical components add together to form a resulting vertical force Fz = 4.F.cos (ωt).

The maximum vertical vibratory force Fz is for example between 20000 and 30000 daN, following the rotation of the four shaft lines 51 to 54, and can be of the order of 24720 daN at a frequency of 70 Hz or 4200 tr / min.

In conclusion, during this second cycle, when the eccentrics are all oriented in the same direction and the same direction, the vertical components are added and we finally obtain a resultant force of maximum vibration. At each frequency given by the variator corresponds a different effort due to the relation F = m.ω ² .R.

On the figure 6 there is shown a third control cycle of the rotation drive of the lines of vibrators 5, where the shafts of the same pair of vibrator lines, respectively rear and front, are at first t = 0 opposite one to the other, as in the case of the first cycle illustrated in figure 4 and associated with a global force of zero vibration.

In a second time t1, the shafts 51 to 54 are out of phase with respect to the vertical axis Z at a non-zero angle. As described below, the introduction of a phase shift, with respect to a starting position of the eccentrics ensuring a zero vertical force, makes it possible to control the vibration forces between the rear and the front of the mold 3.

• le premier arbre 51 est déphasé d'un angle δ1 dans le sens négatif, opposé à son sens de rotation ultérieur ;
• le deuxième arbre 52 est déphasé d'un angle δ1 également dans le sens négatif, correspondant à son sens de rotation ultérieur ;
• le troisième arbre 53 est déphasé d'un angle δ2 dans le sens positif, correspondant à son sens de rotation ultérieur ;
• le quatrième arbre 54 est déphasé d'un angle δ2 dans le sens positif, opposé à son sens de rotation ultérieur.

The phase shifts introduced at time t1 are the following:

• the first shaft 51 is out of phase with an angle δ1 in the negative direction, opposite to its subsequent direction of rotation;
• the second shaft 52 is out of phase by an angle δ1 also in the negative direction, corresponding to its subsequent direction of rotation;
• the third shaft 53 is out of phase by an angle δ2 in the positive direction, corresponding to its subsequent direction of rotation;
• the fourth shaft 54 is out of phase by an angle δ2 in the positive direction, opposite to its subsequent direction of rotation.

• les composantes verticales, en Z, des différentes forces centrifuges F1 à F4 sont respectivement $$\mathrm{F}1\mathrm{z}=\mathrm{F}.\cos \left(\mathrm{\delta }1-\mathrm{\omega t}\right)\mathrm{pour\; le\; premier\; arbre}\mathrm{51,}$$
  
  $$\mathrm{F}2\mathrm{z}=\mathrm{F}.\cos \left(\mathrm{\delta }1+\mathrm{\omega t}\right)\mathrm{pour\; le\; deuxième\; arbre}\mathrm{52,}$$
  
  $$\mathrm{F}3\mathrm{z}=\mathrm{F}.\cos \left(\mathrm{\delta }2+\mathrm{\omega t}\right)\mathrm{pour\; le\; troisième\; arbre}\mathrm{53,}$$
  
  
  et $$\mathrm{F}4\mathrm{z}=\mathrm{F}.\cos \left(\mathrm{\delta }2-\mathrm{\omega t}\right)\mathrm{pour\; le\; quatrième\; arbre}\mathrm{54,}$$
  
• les composantes horizontales, en X, des différentes forces centrifuges F1 à F4 sont respectivement $$\mathrm{F}1\mathrm{x}=\mathrm{F}.\sin \left(\mathrm{<figure-callout\; id="1"\; label="\delta "\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">\delta </figure-callout>}1-\mathrm{\omega t}\right)\mathrm{pour\; le\; premier\; arbre}\mathrm{51,}$$
  
  $$\mathrm{F}2\mathrm{x}=\mathrm{F}.\sin \left(\mathrm{<figure-callout\; id="1"\; label="\delta "\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">\delta </figure-callout>}1+\mathrm{\omega t}\right)\mathrm{pour\; le\; deuxième\; arbre}\mathrm{52,}$$
  
  $$\mathrm{F}3\mathrm{x}=\mathrm{F}.\sin \left(\mathrm{<figure-callout\; id="2"\; label="\delta "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\delta </figure-callout>}2+\mathrm{\omega t}\right)\mathrm{pour\; le\; troisième\; arbre}\mathrm{53,}$$
  
  et $$\mathrm{F}4\mathrm{x}=\mathrm{F}.\sin \left(\mathrm{<figure-callout\; id="2"\; label="\delta "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\delta </figure-callout>}2-\mathrm{\omega t}\right)\mathrm{pour\; le\; quatrième\; arbre}\mathrm{54,}$$
  

Then, the shafts 51 to 54 are all rotated, at the same speed ω and synchronously, in opposite directions within each pair (as already mentioned), so that:

• the vertical components, in Z, of the different centrifugal forces F1 to F4 are respectively $$\mathrm{F}1\mathrm{z}=\mathrm{F}.\cos \left(\mathrm{\delta }1-\mathrm{\omega t}\right)\mathrm{for\; the\; first\; tree}51$$
  
  $$\mathrm{F}2\mathrm{z}=\mathrm{F}.\cos \left(\mathrm{\delta }1+\mathrm{\omega t}\right)\mathrm{for\; the\; second\; tree}52$$
  
  $$\mathrm{F}3\mathrm{z}=\mathrm{F}.\cos \left(\mathrm{\delta }2+\mathrm{\omega t}\right)\mathrm{for\; the\; <figure-callout\; id="53"\; label="third\; tree"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">third\; tree</figure-callout>}53$$
  
  
  and $$\mathrm{F}4\mathrm{z}=\mathrm{F}.\cos \left(\mathrm{\delta }2-\mathrm{\omega t}\right)\mathrm{for\; the\; <figure-callout\; id="54"\; label="fourth\; tree"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">fourth\; tree</figure-callout>}54$$
  
• the horizontal components, in X, of the different centrifugal forces F1 to F4 are respectively $$\mathrm{F}1\mathrm{x}=\mathrm{F}.\sin \left(\mathrm{\delta }1-\mathrm{\omega t}\right)\mathrm{for\; the\; first\; tree}51$$
  
  $$\mathrm{F}2\mathrm{x}=\mathrm{F}.\sin \left(\mathrm{<figure-callout\; id="1"\; label="\delta "\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">\delta </figure-callout>}1+\mathrm{\omega t}\right)\mathrm{for\; the\; second\; tree}52$$
  
  $$\mathrm{F}3\mathrm{x}=\mathrm{F}.\sin \left(\mathrm{<figure-callout\; id="2"\; label="\delta "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\delta </figure-callout>}2+\mathrm{\omega t}\right)\mathrm{for\; the\; <figure-callout\; id="53"\; label="third\; tree"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">third\; tree</figure-callout>}53$$
  
  and $$\mathrm{F}4\mathrm{x}=\mathrm{F}.\sin \left(\mathrm{\delta }2-\mathrm{\omega t}\right)\mathrm{for\; the\; <figure-callout\; id="54"\; label="fourth\; tree"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">fourth\; tree</figure-callout>}54$$
  

The vertical force resulting from the rotation of the first 51 and second 52 shafts, said rear vibratory force Fzar, acting mainly on the rear part of the mold, has the following relationship: $$\mathrm{Fzar}=\mathrm{F}1\mathrm{z}+\mathrm{F}2\mathrm{z}=2.\mathrm{F}.\sin \left(\mathrm{<figure-callout\; id="1"\; label="\delta "\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">\delta </figure-callout>}1\right).\sin \left(\mathrm{\omega t}\right).$$

The vertical force resulting from the rotation of the third 53 and fourth 54 shafts, said vibratory force before Fzav, acting mainly on the front part of the mold, has the following relation: $$\mathrm{Fzav}=\mathrm{F}3\mathrm{z}+\mathrm{F}4\mathrm{z}=2.\mathrm{F}.\sin \left(\mathrm{\delta 2}\right).\sin \left(\mathrm{\omega t}\right).$$

The overall horizontal force Fh resulting from the rotation of the shafts 51 to 54 has the following relationship: $$\mathrm{F\; H}=\mathrm{F}1\mathrm{x}+\mathrm{F}2\mathrm{x}+\mathrm{F}3\mathrm{x}+\mathrm{F}4\mathrm{x}=2.\mathrm{F}.\sin \left(\mathrm{\omega t}\right).\left(\cos \mathrm{\delta }1-\mathrm{<figure-callout\; id="2"\; label="cos\; \delta "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">cos\; </figure-callout>}\mathrm{\delta }\mathrm{}2\right).$$

If the phase shift angles δ1 and δ2 are different, then the rear vibratory force Fzar is different from the vibratory force before Fzav, thus allowing to have a different vibratory movement between the back and the front of the mold. It is thus possible to obtain a greater force on a portion of the vibratory table then giving different amplitudes to this part of table, hence a different behavior of the mold and concrete. On the other hand, a horizontal resultant force Fh will also be generated but, of low value, it will have no harmful impact on the mechanical systems or the quality of the products manufactured.

The vibrating press according to the invention thus makes it possible to differentiate the rear vibratory force from the front vibratory force for a single vibrating table, which makes it possible to compensate for the filling defects related to the advance of the distribution drawer above the mold.

If the phase shift angles δ1 and δ2 are equal, then the rear vibratory force Fzar is equal to the vibratory force before Fzav, thus allowing identical vibratory movement between the rear and the front of the mold. Such uniform vibratory movement is desirable especially during the compaction phase following the filling phase of the mold. In addition, in this case the resulting horizontal force Fh is zero.

It should be noted that the phase during which it is useful to have a different force between the front and the back of the mold is the filling phase. To obtain an effective vibration movement of the mold, it is necessary to create an amplitude of movement on the mold via the table without having too much frequency: for example, it is desirable to obtain a frequency of the order of 50 at 60 Hz for a wooden molding board and 60 to 65 Hz for a metal molding board. As a reminder, whatever the phase, each of the engines rotates at the same speed, including when there is a different force between the front and the back of the mold.

The vibratory force should not shake the mold too much and it is usually between 11000 and 15000 daN for the table.

Thus, each pair of tree lines develops between 5500 and 7500 daN. The permissible difference between the force before Fzav and the rear force Fzar is for example 1000 daN maximum. Under these conditions, the horizontal force Fh generated is between 400 and 700 daN.

Of course the implementation example mentioned above is not limiting in nature and other details and improvements can be made to the vibrating press according to the invention, without departing from the scope of the invention where for example other forms of eccentrics can be realized, where the number of vibrator lines can be increased to take into account the length of the mold by integrating several pairs of vibrator lines and playing on the phase shifts between these pairs of lines, where the dispensing means can be distinct from the movable drawer while creating the same phenomenon of inhomogeneity in the filling of the mold.

Claims (13)

1. A vibrating press for the production of construction elements comprising:

   - a vibrating table (2) equipped with several vibrator lines (5) spaced from each other and with control means for controlling the driving of said vibrator lines (5), the vibrator lines (5) each comprising a rotary shaft (51; 52; 53; 54) on which at least one eccentric (55) of the unbalancing mass or flyweight type is mounted,

   - a mold (3) disposed on said vibrating table (2) such that the vibrator lines (5) transmit a vibrating movement to said mold (3), and

   - a dispensing means (4) which allows supplying the mold (3) with a fresh product to be molded, said dispensing means (4) being displaceable in translation above the mold (3) along a displacement direction (X) and between a rear portion (32) and a front portion (33) of the mold,

   characterized in that the axes of the rotary shafts of the vibrator lines (5) extend in the horizontal plane (X, Y) and substantially perpendicular to the displacement direction (X) of the dispensing means (4), the axes of the rotary shafts of the vibrator lines (5) being also parallel, and in that the control means are capable of allowing the vibrating movement transmitted by said vibrator lines (5) to said mold to be distinct between the rear portion (32) and the front portion (33) of the mold (3).
2. The press according to claim 1, wherein the control means are designed to control the phase shift in the rotation of the rotary shafts (51, 52, 53, 54), and the corresponding eccentrics (55), in order to vary the vibrating force between the rear portion (32) and the front portion (33) of the mold (3).
3. The press according to claims 1 or 2, comprising at least two pairs of vibrator lines (5), including:

   - a rear pair disposed under the rear portion (32) of the mold (3) and comprising a first (51) and a second (52) rotary shaft, and

   - a front pair disposed under the front portion (33) of the mold (3) and comprising a third (53) and a fourth (54) rotary shaft.
4. The press according to claim 3, wherein the control means are designed to control:

   - the orientation and the speed of rotation of the four shafts (51, 52, 53, 54), and

   - the relative phase shift in the rotation of each of said four shafts, equivalent to the respective inclination of the eccentric(s) (55) of said shafts relative to a main direction,

   so that the vertical component of the centrifugal force (Fzar) resulting from the rotation of the first (51) and second (52) shafts is distinct from the vertical component of the centrifugal force (Fzav) resulting from the rotation of the third (53) and fourth (54) shafts.
5. The press according to claim 4, wherein the control means are designed:

   - to orient the eccentric(s) of the first shaft (51) in a main direction (Z) and in a first orientation, and to orient the eccentric(s) of the second shaft (52) in the same main direction and in a second orientation opposite to the first orientation,

   - to orient the eccentric(s) of the third shaft (53) in the same main direction (Z) and in the second orientation, and to orient the eccentric(s) of the fourth shaft (54) in the same main direction and in the first orientation,

   - to phase shift the first shaft (51) by a first angle (δ1) in a first orientation of rotation and to phase shift the second shaft (52) by the same first angle (δ1) in the same first orientation of rotation,

   - to phase shift the third shaft (53) by a second angle (δ2), distinct from the first angle (δ1), in a second orientation of rotation opposite to the first orientation of rotation, and to phase shift the fourth shaft (54) by the same second angle (δ2) in the same second orientation of rotation,

   and then

   - to allow the rotation of the first, second, third and fourth shafts at the same speed and synchronously,

   - to ensure that the first (51) and third (53) shafts rotate in the second orientation of rotation,

   - to ensure that the second (52) and fourth (54) shafts rotate in the first orientation of rotation,

   so that the vibrating movement transmitted by the vibrator lines (5) to the mold (3) is distinct between the rear portion (32) and the front portion (33) of the mold (3).
6. The press according to any one of the preceding claims, in which the control means are capable of also allowing the vibration movement transmitted by the vibrator lines (5) to said mold (3) to be identical between the rear portion (32) and the front portion (33) of the mold (3).
7. The press according to claim 6 in combination with any one of claims 3 to 5, wherein the control means are also designed to control:

   - the orientation and the speed of rotation of the four shafts (51, 52, 53, 54), and

   - the relative phase shift in the rotation of each of said four shafts, equivalent to the respective inclination of the eccentric(s) of said shafts relative to a main direction,

   so that the vertical component of the centrifugal force (Fzar) resulting from the rotation of the first (51) and second (52) shafts is equal to the vertical component of the centrifugal force (Fzav) resulting from the rotation of the third (53) and fourth (54) shafts.
8. The press according to claim 7, wherein the control means are designed:

   - to orient the eccentric(s) of the first, second, third and fourth shafts in the same main direction (Z) and in the same orientation,

   and then

   - to allow the rotation of the first, second, third and fourth shafts at the same speed and synchronously,

   - to ensure that the first (51) and third (53) shafts rotate in the second orientation of rotation,

   - to ensure that the second (52) and fourth (54) shafts rotate in the first orientation of rotation opposite to the second orientation of rotation.

   so that the vibrating movement transmitted by the vibrator lines (5) to the mold (3) is identical between the rear portion (32) and the front portion (33) of the mold (3).
9. The press according to any one of claims 2 to 8, wherein the rotary shafts (51, 52, 53, 54) support several eccentrics oriented in the same direction and the same orientation.
10. The press according to any one of the preceding claims, wherein the dispensing means (4) is movable in translation along a longitudinal axis (X) of the press, and the vibrator lines (5) extend along a transverse axis (Y) of the press substantially normal to said longitudinal axis (X).
11. The press according to any one of the preceding claim, wherein the eccentrics (55) are all identical in shape and mass.
12. The press according to any one of the preceding claims, wherein the press is of the type comprising a single vibrating table (2).
13. A production method of construction elements including the following steps:

    - providing a mold (3) for the construction elements,

    - filling the mold (3) with fresh product to be molded using a dispensing means (4) displaceable in translation above the mold (3) along a displacement direction (X) and between a rear portion (32) and a front portion (33) of the mold (3),

    - transmitting a vibrating movement to said mold (3) by means of a vibrating table (2) equipped with several vibrator lines (5) spaced from each other, the vibrator lines (5) each comprising a rotary shaft (51; 52; 53; 54) on which at least one eccentric (55) of the unbalancing mass or flyweight type is mounted, characterized in that during the filling of the mold, the step of transmitting the vibrating movement comprises the following steps:

    - driving in rotation the rotary shafts of the vibrator lines (5) along the respective axes extending in the horizontal plane (X, Y) and substantially perpendicular to the displacement direction (X) of the dispensing means (4), the axes of the rotary shafts of the vibrator lines (5) being also parallel, and

    - controlling the driving in rotation of said rotary shafts of said vibrator lines (5) to allow the vibration movement transmitted by said vibrator lines (5) to said mold (3) to be distinct between the rear portion (32) and the front portion of the mold (33).

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