EP0382653A1 - Vibrating press for moulding concrete products - Google Patents

Abstract

The press according to the invention comprises a vibrating table (3) supported by a fixed frame (1), while the other members such as the mould support (17), the presser (26) and the removable moulding plate (11) are supported by a second chassis (13) which is vertically movable in relation to the fixed frame (1). In the low position of the second chassis (13), the removable moulding plate (11) rests on the vibrating table (3), whereas in the raised position of the second chassis (13), the removable moulding plate (11) and the mould are separated from the vibrating table (3). The invention applies to the manufacture of products moulded in vibrated concrete such as binding or paving stones. <IMAGE>

Description

The present invention relates to automatic production lines for molded vibrated concrete products, and more particularly to vibration presses for molding products such as concrete products, in which the demoulding station is located vertically and above the vibration station. Such presses are usually used for the manufacture of concrete blocks or pavers.

In the currently known vibration presses for molding concrete products, the following elements are used:
- A vibrating table, composed of a thick sheet under which is fixed a vibration drive assembly comprising at least two unbalanced motorized vibrators, of horizontal axes and driven in rotation according to opposite directions of rotation; the unbalances generate a substantially vertical unidirectional resulting vibration force; the vibrating table is connected to a frame by an elastic connection;
- an upper surface of the vibrating table, shaped to receive and support a removable molding plate;
- A mold, shaped to form the walls of the product to be molded, with means for holding the mold in abutment against the upper surface of the removable molding plate itself placed on the vibrating table;
- a presser with grid, movable vertically, coming to be inserted in interstices of the upper face of the mold, to form the hollow parts of the product to be molded;
- Means for supplying fresh products to be molded, such as a supply pipe and sealing members, for bringing the fresh product from a reserve silo.

During the filling of the mold with fresh product, the vibrating members vibrate the vibrating table and the mold. At the end of the molding, it is essential to remove the effect of the vibration before removing the mold, failing which the fresh molded concrete product would disintegrate immediately.

In traditional presses, the rotary vibration-producing devices are then stopped, and, after the complete stop, the mold is removed and the molded products are removed.

Such traditional devices have many drawbacks, and in particular:
- the engines undergo frequent starting operations;
- To avoid very long waiting times, it is necessary to brake the motors violently at the end of the molding step, and the motors then undergo sudden stops;
- the installation must be oversized in power, to support frequent starts and stops;
- energy consumption is high;
- the transient regimes during acceleration and braking of vibrator motors introduce peaks of vibration intensity;
- known structures introduce vibration transmissions into the chassis and the organs of the press itself;
- significant vibrations require the provision of significant and expensive civil engineering;
- starts and stops introduce loss of time in the manufacturing cycle.

To avoid these drawbacks, structures have been proposed in which it is no longer necessary to stop the rotary vibration generating elements at the end of molding in order to suppress the effect of the vibrations on the mold, and it is no longer necessary to restart the rotary vibrating elements to apply the vibrations to the mold. It is then possible to use rotary members generating vibrations driven at constant speed, a single start-up being necessary during the start-up of the installation, a single stop being necessary at the end of operation of the installation, the speed of the rotary members vibration generators that can be kept constant during the entire service life of the installation, without modification when going from a first molding operation to a successive molding operation.

These structures are described for example in documents DE-A-3 004 642 or DE-A-2 815 870. The vibrating table is then connected by elastic means to a frame movable relative to a frame, while the other organs of the press are carried by said fixed frame. Driving means make it possible to move the movable frame relative to the frame between a high position in which the vibrating table is in contact with the molding plate, and a low position in which the vibrating table is separated from the molding plate which then rests on fixed supports of the frame.

Such structures have significant drawbacks which led to their abandonment, in particular:
- the drive means making it possible to move the movable chassis are permanently subjected to vibrations, which leads to their rapid deterioration,
- vibrations are transmitted continuously through the frame to all parts of the press, including the mold, even in the low position of the mobile chassis,
- Because of the significant vibrations of the mobile chassis, it is difficult to adjust and fix the relative position of this mobile chassis relative to the frame, so that it is difficult to adjust the vibration.

The object of the present invention is to avoid these drawbacks.

The new design according to the invention is such that the structure itself of the press, apart from the molding members, does not undergo any significant vibration. The mechanical parts of the press only support almost negligible vibration stresses, and are subjected to less fatigue. Civil engineering can be reduced compared to conventional solutions.

The structure of the invention makes it possible to easily adjust the amplitude of the vibration transmitted to the molding plate.

The invention also makes it possible to suppress, almost instantaneously, any significant vibration of the mold after the vibration operation. This results in better mechanical resistance of the products obtained, and the possibility of immediate demoulding. It has indeed been observed that, in known devices, non-negligible vibrations are still transmitted to the concrete after the vibration operation, which prevents rapid demolding.

To achieve these and other objects, the vibration press for molding concrete products according to the invention uses the essential organs of known presses, in which the vibrating assembly and the molding assembly can be separated. relative to each other at any time, and vice versa. According to the invention, the organs are assembled into two families:
- A first family, formed by a vibrating table and its vibration drive means, is carried by a fixed frame to which it is connected by an elastic connection;
- a second family, formed by a mold and its support, a presser, means for supplying fresh product to be molded, is carried by a second common chassis;
- a movable mold support, carrying a mold with the interposition of elastic members, can admit a raised position for demolding in which the mold and the mold support are separated from the removable molding plate to release the molded products and a lowered position molding with the mold held in abutment on the upper face of the removable molding plate;
the second common chassis of the second family of members is movable relative to the fixed frame between a first contact position in which the removable molding plate is in contact and supported by the vibrating table, against which it is resiliently supported, and a second demolding position in which the removable molding plate is carried by carrying members integral with the second common frame of second family of members so that, in the second demolding position, the removable molding plate is separated from the vibrating table and is no longer subject to vibrations;
- Actuators urge the second common chassis between two distinct positions corresponding respectively to the two removable molding plate positions defined above.

Thus, the displacement of the removable molding plate relative to the vibrating table is carried out by displacement of the second movable common frame relative to the first fixed common frame.

Preferably, in the first contact position in which the plate is in contact and supported by the vibrating table, fixed lower stops limit the movement of the removable molding plate downwards, so that said removable molding plate rests on said lower fixed stops during a first portion of the vibration cycle, and rests on the vibration table during a second portion of the vibration cycle. In this way, the fixed lower stops of movement limitation of the removable molding plate determine a fixed position of removable molding plate from which the vibrating table prints the vibration oscillations to said removable molding plate. This structure considerably improves the regularity of the vibrations imparted to the mold, and improves the quality of the molded products obtained.

The transmission of the movement from the second movable common frame to the removable molding plate can be carried out in a simple manner, by providing lifting crossmembers, integral with the second mobile chassis, arranged in such a way that, in the lower position of the second mobile chassis, the removable molding plate rests on the vibrating table and is then separated from the lifting crossmembers, and, in the lifting position or demoulding, the removable molding plate is carried by the lifting crosspieces and is then separated from the vibrating table.

Preferably, lower support stops limit the movement of the second movable chassis downwards, so as to fix the relative position of the members during the vibration.

In addition, it is advantageous to provide precise and fixed upper support stops to limit the displacement of the second movable frame upwards, and thus to define a precise position in height of the removable molding plate relative to a conveyor of exit. This arrangement makes it possible to evacuate the products after demolding, avoiding the production of shocks during transfer.

• - la figure 1 est une vue générale de face d'une presse selon la présente invention en position de vibrage ;
• - la figure 2 est une vue générale de face de la presse selon l'invention en position de démoulage ;
• - la figure 3 est une vue générale de côté d'une presse selon l'invention ;
• - la figure 4 est une vue partielle de face représentant le détail des liaisons des différents organes en position de vibration ; et
• - la figure 5 est une vue partielle de face représentant le détail de liaison des différents organes en position de démoulage.

Other objects, characteristics and advantages of the present invention will emerge from the following description of particular embodiments, given in relation to the attached figures, among which:

• - Figure 1 is a general front view of a press according to the present invention in the vibrating position;
• - Figure 2 is a general front view of the press according to the invention in the release position;
• - Figure 3 is a general side view of a press according to the invention;
• - Figure 4 is a partial front view showing the detail of the connections of the various members in the vibration position; and
• - Figure 5 is a partial front view showing the connection detail of the various members in the release position.

In the embodiment shown in the figures, the vibration press according to the invention comprises a first common chassis 1 consisting of a fixed frame anchored to the ground 2, and carrying a vibrating table 3 and its vibration drive means . The vibrating table 3 is composed of a thick sheet 4, connected to the first chassis 1 by elastic suspensions 5. Two unbalanced rotary vibrators 6 and 7, mounted along two horizontal axes, are carried under the sheet 4 as shown in the figures , and are rotated by a motor electric 8 to which they are connected by a mechanical transmission allowing the oscillations of the vibrating assembly. Candles 9, surmounting the thick sheet 4, define the upper surface 10 of the vibrating table, intended to receive and support a removable molding plate 11. The vibrators 6 and 7 are synchronized, and driven in rotation according to directions of rotation opposites. The unbalances are arranged at appropriate angles so that, when the vibrators 6 and 7 are rotated, they produce a substantially vertical unidirectional vibration force.

In the embodiment shown, the vibrating table also comprises fixed lower stops 12, integral with the first frame 1, the upper surface of which is arranged in a horizontal plane 100 defining an intermediate position of the upper plane 10 of the vibrating table during the in vibrating the thick sheet 4. Thus, during the rotational driving of the vibrators 6 and 7, the upper plane 10 moves vertically according to the amplitude of vibration, on either side of the horizontal plane 100 defined by the upper ends of the fixed stops 12. During part of the vibration cycle, the removable molding plate 11 is thus carried by the fixed lower stops 12; during the other part of the vibration cycle, the removable molding plate 11 is carried by the candles 9 of the vibrating table.

The press according to the invention further comprises a second common frame 13, movable vertically with respect to the first fixed frame 1. In the embodiment shown, the second common frame 13 is articulated along a fixed horizontal axis of rotation 14 disposed at the 'rear of the device, and is moved by actuators 15 and 16 such as cylinders. Thus, the second common frame 13 can take two significant positions, namely a first vibration position shown in Figure 1 allowing the vibration of the concrete to be molded, and a second position shown in Figure 2 allowing the release of vibrated concrete.

The second common frame 13 comprises a movable support 17 on which a mold 170 can be adapted shaped to form the walls of the product to be molded. The mobile support 17 is composed of two lateral carriages 18 and 19 and two elastic connections 20 and 21. The carriages 18 and 19 slide vertically on vertical guides 22 and 23 of the second common frame 13, and are driven by jacks 24 and 25 in a relative movement relative to the second common frame 13. During this movement, the movable mold support 17 moves between two main positions, a molding position in which the movable support 17 is lowered near the vibrating table 3, and a withdrawal position in which the movable mold support 17 is raised, to allow demolding and evacuation of the molded products.

The second common frame 13 further comprises a presser 26, carried by a carriage 27 sliding on the vertical guides 22 and 23 of the second common frame 13, and actuated vertically by a jack 28. The presser 26 carries a grid 29 shaped to come s 'Insert, in the low position of the carriage 27, in the interstices provided in the upper wall of the mold 170, to press the solid parts of the elements to be molded.

According to the invention, the second common chassis 13 also comprises two crosspieces 30 and 31 forming carrying members, arranged on either side of the vibrating table 3 and in positions such that, in the lower position of the second chassis 13, the crosspieces 30 and 31 are below the plane 100 defined by the lower stops 12 of the vibrating table, and, in the high position of the second common frame 13, the crosspieces 30 and 31 are above the upper limit plane occupied by the surface upper 10 of vibrating table during its vertical vibrations, the crosspieces 30 and 31 then carrying the removable molding plate 11.

Means for supplying fresh product to be molded, shown in FIG. 3, make it possible to bring the fresh concrete inside the mold from a reserve silo. For this, a hopper 32 drops the fresh concrete into a box-drawer 33 provided with an agitator 34. After filling, the box-drawer 33 is moved and brought to the mold 170. The concrete flows into the mold. The box-drawer 33 is then brought back under the hopper 32.

In the embodiments in which the second chassis 13 is relatively light, it may prove useful to provide means for locking the second common chassis 13 when the latter is in the low position, thus avoiding the effect of vibrations transmitted by the elastic connections 20 and 21. However, the second common chassis 13 should, in most cases, be heavy enough for the vibration transmissions become completely negligible, and it will then not be necessary to provide means for locking the second common chassis 13 in the low position.

Preferably, the low position of the second common chassis 13 must be determined with sufficient precision, since it notably defines the pressure exerted by the carriages 18 and 19 on the movable support 17 of the mold via the elastic connections 20 and 21. Too much pressure risks suffocating the vibrations produced by the vibrating table 3; too low a pressure risks producing untimely detachments of the mold relative to the removable molding plate 11. Provision is made for this for fixed lower support stops against which the second common frame 13 comes to bear in the low position.

According to an advantageous embodiment, the elastic connections 20 and 21 consist of pneumatic elements receiving compressed air by pipes controlled by a proportional distributor delivering an adjustable air pressure. The air pressure adjustment then makes it possible to adjust the pressing force of the mold on the molding plate and on the vibrating table.

It is also necessary to provide means for making the position of the removable molding plate 11 precise when evacuating the molded products. This position is defined by the position of the crosspieces 30 and 31 which then carry the removable molding plate 11. It is therefore useful to provide high stops limiting the movement of the second common frame 13 upwards. This produces a shock-free evacuation of the molded products. Optionally, the upper stops are matched with damping means, to avoid the metal-to-metal impact at the end of the travel of the second chassis 13.

The operation of the device is described below.

At the start of the operating period, the electric motor 8 is powered by an electric power source, and drives the vibrators 6 and 7 in rotation. The rotation is maintained throughout the operating period, at a substantially constant speed which determines the amplitude and frequency of vibration. The vibration of the vibrating table 3 takes place in a substantially vertical direction.

The second chassis 13 is initially in the raised position, as shown in FIG. 2. In this position, a removable molding plate 11 is brought to bear on the crosspieces 30 and 31 of the second movable common chassis 13. The mold 170 is lowered, carried by the movable mold support 17, by actuating the jacks 24 and 25. The mold 170 is then held in elastic support on the upper surface of the removable molding plate 11, by the elastic connections 20 and 21.

In this position, the fresh concrete is brought, by the means for supplying fresh product to be molded, as far as the mold 170 placed on its removable molding plate 11.

The second common frame 13 is then lowered, by the actuators 15 and 16, to bring it to the low position shown in FIG. 1. In this position, the crosspieces 30 and 31 release the removable molding plate 11, which then rests on the vibrating table 3, sometimes on the candles 9, sometimes on the fixed lower stops 12. In its downward movement, the removable molding plate 11 is accompanied by the movable mold support 17 and the carriages 18 and 19. The vibrations produced by the vibrators 6 and 7 are then transmitted to the removable molding plate 11 and to the mold, as well as to the product contained in the mold.

The presser 26 is lowered, by actuation of the jack 28, to bring the grid 29 into the mold.

Under the effect of vibrations, the grid 29 gradually penetrates into the mold by compressing the concrete. When the grid 29 is lowered to a predetermined dimension, it is considered that the vibrations are sufficient and the second common frame 13 is lifted by the actuators 15 and 16. The cross members 30 and 31 then lift the assembly formed by the removable molding plate 11, the movable mold support 17 and the mold 170 which is supported, as well as the carriages 18 and 19, as far as the high position shown in FIG. 2. In this position, the removable molding plate 11 is no longer at contact with the vibrating table 3, and the products can be removed from the mold by lifting the mold 170 and the presser 26 by actuating the jacks 24, 25 and 28 urging the carriages 18 and 19 upwards. The molded products are then discharged by a discharge device, not shown.

The structure according to the invention is advantageous because the vibrations produced by the vibrators 6 and 7 are transmitted on the one hand to the elements to be vibrated placed on the removable molding plate 11, and on the other hand part to the first fixed frame 1. The first fixed frame 1, connected to the vibrating table by the elastic suspensions 5, is relatively easy to anchor in the ground, so that the civil engineering to be provided is very reduced. The vibrations are practically not transmitted to the second common chassis 13, due to the presence of the elastic connections 20 and 21 between the mold and the mold actuating members, and due to the total separation between the fixed chassis 1 and the second common chassis 13. The fixed nature of the first chassis 1 simplifies the construction of the device. The mechanical members ensuring the displacement of the second chassis 13 are not subjected to vibrations during most of their travel.

The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof contained in the field of claims below.

Claims (8)

1 - Vibration press for molding products such as concrete products, comprising:
- a vibrating table (3), with vibration drive means,
- an upper surface (10) of the vibrating table (3) intended to support a removable molding plate (11),
a presser (26) with a grid (29), movable vertically and urged by actuating means (28), the grid (29) being inserted into the interstices of the mold,
- means for supplying fresh product to be molded,
characterized in that:
- a movable mold support (17), carrying a mold (170) with the interposition of elastic members (20, 21), can admit a raised release position in which the mold and the mold support (17) are separated from the removable molding plate (11) for releasing the molded products and a lowered molding position with the mold held in abutment on the upper face of the removable molding plate (11),
- the vibration drive members are assembled into a first family comprising the vibrating table (3) and its vibration drive means (6, 7), and are carried by a first common frame (1) fixed by a link elastic (5),
the other members are assembled in a second family comprising the mold and its movable mold support (17), the presser (26), the means for supplying fresh product to be molded, and are carried by a second common frame (13 ),
- the second common chassis (13) of the second family of members is movable relative to the first fixed frame (1) between a first contact position in which the removable molding plate (11) is in contact and supported by the vibrating table (3), against which it is resiliently supported, and a second demolding position in which the removable molding plate (11) is separated from the vibrating table (3) and is carried by carrying members (30, 31 ) integral with the second common chassis (13) of the second family of members, - the second common chassis (13) is driven by actuators (15, 16) to bring it into two positions corresponding respectively to the two removable plate positions of molding (11) relative to the table vibrating (3). 2 - Vibration press according to claim 1, characterized in that it further comprises fixed lower stops (12) limiting movement of the removable molding plate (11). 3 - Vibration press according to one of claims 1 or 2, characterized in that the carrying members consist of lifting crosspieces (30, 31), integral with the second common movable chassis (13), arranged so that, in the lower position of the second common frame (13) the removable molding plate (11) rests on the vibrating table (3) and is separated from the lifting crosspieces (30, 31), and, in the lifting position of the second common frame ( 13) the removable molding plate (11) is carried by the lifting crosspieces (30, 31) and is separated from the vibrating table (3). 4 - Vibration press according to any one of claims 1 to 3, characterized in that it further comprises means for locking the second common chassis (13) in the lower position of said chassis. - Vibration press according to any one of claims 1 to 4, characterized in that it comprises lower support stops defining the support position of the second common frame (13) in the low position, to determine the relative position organs during the vibration stage. 6 - Vibration press according to claim 5, characterized in that it further comprises high stops to limit the travel of the second common frame (13) upwards, precisely defining the position of the removable molding plate ( 11) relative to an output conveyor during the evacuation of the molded elements. 7 - Vibration press according to claim 6, characterized in that the upper stops are associated with damping means to avoid metal on metal shocks. 8 - Vibration press according to any one of claims 1 to 7, characterized in that the elastic members (20, 21) are pneumatic elements receiving compressed air by pipes controlled by a distributor delivering a pressure of adjustable air, to adjust the pressing force of the mold on the removable molding plate (11) and on the vibrating table (3).

Images