EP0023442A1 - Press for moulding concrete products - Google Patents

Abstract

The molding press comprises a vibrating table (12,) a board (14), a mold (15) movable vertically between an upper demolding position and a lower molding position, and means (17, 21, 30, 40) to secure, during the vibration phase of the concrete in the mold, the mold 15 to the vibrating table (12), the board (14) then being clamped between the mold and the table.

Description

The present invention relates generally to molding presses and relates more particularly to a molding press for concrete products, such as for example concrete blocks, by subjecting the concrete to a vibration operation.

In the prior art, presses for molding concrete products are already known. In general, these presses include a chassis, a horizontal vibrating table supported by a unidirectional vibrating device with vertical action, a system of feeding boards one by one on the vibrating table, a mold movable vertically thanks to hydraulic jacks , each cylinder having its piston fixed to the mold and its cylinder fixed to the chassis, and a concrete supply system.

However, a press for molding concrete products of the type described above has drawbacks. In fact, during the vibration phase of the concrete in the mold, shocks from the vibrating table occur on the board, and therefore on the mold supported on said board. Under these conditions, the hydraulic cylinders which serve to support the mold on the board, withstand the shocks and transmit them to the chassis. So a such transmission of shocks is noisy, and causes mechanical destruction. It therefore follows that the energy consumption is high and that the yield of the molding press is low.

The object of the present invention is to remedy the aforementioned drawbacks in particular by proposing a press for molding concrete products which has a high yield and which is very reliable.

To this end, the subject of the invention is a press for molding concrete products, of the type comprising a frame, a horizontal vibrating table supported by a unidirectional vibrating device with vertical action, a system for feeding boards one by one on the vibrating table, a mold movable vertically between an upper demolding position and a lower molding position in which it is supported on the board, and a concrete supply system, characterized in that it comprises means for joining, during the vibration phase of the concrete in the mold, said mold to said vibrating table, the board then being sandwiched between the mold and the table, so that the mold, the board and the table form a rigid unitary assembly subjected to vibration .

It is thus understood that, during the vibration phase of the concrete in the mold, the use of means for securing the mold to the vibrating table makes it possible to eliminate any transmission of shocks from the vibrating table to the mold. Consequently, there is no longer any shock transmission to the chassis, and on the other hand, the hydraulic cylinders fixed to the chassis and to the mold are no longer used to press the latter on the table. vibrant. In addition, a better distribution of vibrations is achieved, and a saving of 40 to 50% of energy.

According to another characteristic of the invention, the securing means comprise lugs integral with the mold and extending towards the vibrating table, clamps or jaws intended to grip the lower ends of said lugs, means for controlling the opening and the closing the jaws, as well as means for applying said mold to the vibrating table with a predetermined force.

According to yet another characteristic of the invention, the last aforementioned means comprise means for pulling or pushing, relative to the vibrating table, supports for the jaws when the latter are clamped on the lower end of the legs.

• La figure 1 est une vue de face en élévation, avec arrachements partiels, de la presse à mouler selon l'invention, la. partie droite de la figure représentant le moule en position de moulage, et la partie gauche de la figure représentant le moule en position de démoulage.
• La figure 2 est une vue en coupe selon la ligne brisée II-II de la figure 1, le moule étant en position de moulage.

The invention will be better understood and other objects, characteristics, details and advantages thereof will appear more clearly during the explanatory description which follows, made with reference to the appended drawings given solely by way of example illustrating a method of realization of the invention and in which:

• Figure 1 is a front elevational view, partially broken away, of the molding press according to the invention, la. right part of the figure representing the mold in the molding position, and the left part of the figure representing the mold in the demolding position.
• Figure 2 is a sectional view along the broken line II-II of Figure 1, the mold being in the molding position.

According to a preferred embodiment, and with reference to Figures 1 and 2, a molding press 10 for concrete products, such as for example concrete blocks, comprises a frame 11 (partially shown), and a horizontal vibrating table 12 supported by a unidirectional vibrating device with vertical action constituted for example by two vibrators 13 of a known type. The molding press 10 is supplied with planks of wood or other material 14 by a suitable system of feeding planks 14 one by one onto the vibrating table 12. On the other hand, the press 10 is conventionally supplied with concrete by appropriate means.

In Figure 1, there is shown at 15 a mold which has been broken down into two half-molds in order to show on the right part of Figure 1 the mold 15 in the molding position, and on the left part of Figure 1 the same mold 15 in the demolding position. Of course, the construction of the mold 15 makes it possible to mold a certain number of concrete products at the same time. The mold 15 can be moved vertically between an upper demolding position (left part of FIG. 1) and a lower molding position in which it is pressed on the board 14 (right part of FIG. 1), by the action of one or more hydraulic cylinders (not shown) whose piston is fixed to the mold and whose cylinder or body is fixed to the chassis. As will be understood hereinafter, these hydraulic jacks no longer serve to support the mold 15 on the vibrating table 12.

The mold 15 has a substantially parallelepiped shape, two opposite faces of which are respectively provided externally with three hooking lugs 17, of axis of symmetry 18 and distributed evenly over the length of the mold 15. Thus, the mold 15 has three pairs of legs 17, and we can clearly see in Figure 2 two legs 17 of the same pair. In addition, as clearly shown in FIG. 2, the distance separating the two legs 17 of the same pair is slightly greater than the width of the vibrating table 12. The hooking lugs 17 extend towards the vibrating table 12 and the length of these is greater than the height of the mold. In addition, the lower part of each latch 17 has a recess 19 whose role will appear in the following.

The lower end 20 of each tab 17 is in fact intended to be clamped in two jaws or claws 21, when the mold 15 is in the molding position. Thus, six pairs of jaws 21 are provided to grip the lower ends 20 of the six legs 17, and each two pairs of jaws 21 corresponding to each pair of legs 17 is fixed to a support plate 22 by means of joints 23 (figure 2). Consequently, there are three support plates 22 for the three pairs of legs 17, and two pairs of jaws 21 per plate 22.

Each jaw 21 of the same pair has a projecting part 25 which will engage in the recess 19 of the corresponding tab 17, when the tab-jaw assembly is in the locked position. It should be noted in this connection that the jaw-leg assembly can be replaced by a completely different one. appropriate locking device without departing from the scope of the invention.

It is already understood that, during the vibration phase of the concrete in the mold 15, the mold will be made integral with the vibrating table 12, the board 14 then being sandwiched between the mold 15 and the table 12, so that the mold 15, the board 14 and the table 12 will form a rigid unitary assembly subjected to vibration.

In addition, it should be noted that each jaw 21 has a pivot axis 26 which is slightly offset from the axis of symmetry of the jaw. More specifically, it can be said that the pivot axis 26 is located in the lower part of the jaw 21 between the axis of symmetry of the jaw and the axis 18 of the tab 17. In addition, six stops 27 fixed under the vibrating table 12 cooperate respectively with two jaws 21 belonging to two pairs of jaws associated with the same support plate 22.

As clearly shown in Figure 2, between each support plate 22 and the vibrating table 12, is mounted a pair of pneumatic bellows cylinders 30 supplied with compressed air, each bellows cylinder 30 having an upper flange 31 fixed to the vibrating table 12 and a lower flange 32 fixed to the corresponding support plate 22. In total, there are therefore six pneumatic bellows cylinders 30 which are mounted two by two on a support plate 22. It will be added that the two bellows cylinders 30 of the same pair are arranged so as to ensure the balance of the vibrating table 12.

As seen in Figures 1 and 2, each support plate 22 is connected to the base of the frame 11 via a rigid connection and a single pneumatic bellows cylinder 40 supplied with compressed air in opposite directions two bellows cylinders 30 associated with this plate 22. In total, there are therefore three pneumatic bellows cylinders 40, each cylinder 40 being associated with a pair of cylinders 30. More specifically, each bellows cylinder 40 has a lower flange 41 fixed to the base of the chassis 11 and an upper flange 42 fixed to a rigid connection constituted by two parts forming beams 43 and 44, the part 44 being integral with the corresponding support plate 22. It will be added that the axis 45 of each bellows cylinder 40 is located exactly in the middle of the distance separating the axes 46 of the two bellows cylinders 30 of the same pair (FIG. 2).

The pneumatic bellows cylinders 30 and 40 which vionn to be described and which provide a connection between the vibrating table and the base of the chassis 11, simultaneously constitute means for controlling the opening and closing of the jaws 21, and means for apply the mold 15 on the vibrating table 12 by pulling it down with a predetermined force. More precisely, the bellows jacks 30 and 40 constitute means for pulling or pushing, with respect to the vibrating table 12, the support plates 22 of the jaws 21 when the latter are clamped on the lower end 20 of the lugs 17.

The operation and the manner of using the molding press according to the invention are deduced from the above description and will be explained in this following.

Suppose, for example, that we are in the case shown on the left-hand side of FIG. 1, that is to say that the mold 15 is in its demolding position, that a board 14 is placed on the table. vibrating 12, that the three bellows cylinders 40 are inflated, and that the six bellows cylinders 30 are deflated, the jaws 21 then being open.

To pass from the demolding position represented on the left part of FIG. 1 to the molding position represented on the right part of this same figure, the hydraulic cylinders fixed on the one hand on the upper part of the mold 15 and on the other share on the chassis lower the mold, so that each lower end 20 of each lug 17 enters the opening of the two corresponding jaws 21. At this time, and simultaneously, the three bellows cylinders 40 are deflated and the six bellows jacks 30. This has the effect of lowering the three plates 22 of jaw supports 21, and of tilting the jaws 21 cooperating with the stops 27, so that each pair of jaws 21 grips each tab 17, by engagement of the projections 25 of the jaws 21 in the recess 19 of the legs 17. Under these conditions, the mold 15 is applied to the vibrating table 12 with a predetermined force. We can therefore cut off the power to the hydraulic cylinders attached to the upper part of the mold.

Then, the concrete is introduced into the mold 15, and the vibration phase of the concrete in the mold, which makes it possible to compact the concrete, begins. During this vibration phase, the mold 15, the board 14 and the vibrating table 12 form a rigid unitary assembly subjected to vibration. It will be noted in this connection that the vibration is perfectly sinusoidal, having a determined frequency (for example between 50 and 200 Hertz) and an adjustable amplitude (from 0.2-0.3 to 3 min) as a function of the masses put on the unbalance vibrators 13.

Still during the vibration phase of the concrete in the mold, it is important to note that the hydraulic cylinders no longer have the function of keeping the mold compressed on the board and vibrating table assembly; therefore they can have a very flexible attachment which has the advantage of no longer communicating vibrations to the chassis. On the other hand, the three bellows cylinders 40 being empty, they prohibit any transmission of vibration from the vibrating table to the base of the chassis 11.

When the filling of the mold is carried out, a tamper rigorously adjusts the products.

Then, for demolding, and simultaneously, the three bellows cylinders 40 are inflated and the six bellows cylinders 30 are deflated. This has the effect of raising the three plates 22 for supporting the jaws 21, and opening the jaws 21 cooperating with the stops 27. Under these conditions, the hydraulic cylinders (again supplied) fixed on the one hand to the mold 15 and on the other hand to the chassis, raise the mold 15 - lugs 17 assembly. Consequently, the board 14 supporting the molded concrete products is removed from the press 10 by means appropriate. Another board 14 is then brought to the vibrating table 12, and the molding and demolding operations are carried out as described above.

Of course, the invention is in no way limited to the embodiment described and shown which has been given only by way of example. In particular, it includes all the means constituting technical equivalents of the means described, as well as their combinations, if these are carried out according to the spirit and implemented in the context of the claims which follow.

Claims (7)

1. Press for molding concrete products, of the type comprising a frame, a horizontal vibrating table supported by a unidirectional vibrating device with vertical action, a system of feeding boards one by one on the vibrating table, a mold movable vertically between an upper demolding position and a lower molding position in which it is pressed on the board, a concrete supply system, means for securing, during the vibration phase of the concrete in the mold, said mold to the vibrating table , so that said mold, the board and the table form a rigid integral assembly subjected to vibration and, displacement means for applying said mold to the vibrating table with a predetermined force, characterized in that the securing means comprise legs integral with the mold, extending towards the vibrating table, distributed over the lateral faces of the mold, in order to obtain a uniform application of the mold on the s total surface area of the vibrating table, pairs of jaws or pliers intended to symmetrically enclose the lower ends of each tab, means for controlling the opening and closing of said jaws. 2. Molding press according to claim 1, characterized in that the means for vertical displacement, relative to the vibrating table, of the supports of said jaws when these are clamped on the lower end of said legs, and the control means opening and closing of said jaws are constituted by at least one group of two pneumatic bellows cylinders, superimposed and supplied in opposite directions to each other. 3. Molding press according to claim 2, characterized in that the pneumatic cylinders are mounted between the vibrating table and the base of the chassis, and are supplied so that, during the vibration phase, the lower bellows or cylinders are empty, and prohibit any transmission of vibration from the vibrating table to the chassis. 4. Molding press according to one of claims 1 to 3, characterized in that the chassis comprises fixed stops cooperating with the jaws to cause their opening and their closing when the jaw supports are exceeded by the aforementioned means, respectively towards up and down from the vibrating table. 5. Mold, which can in particular be used with a molding press for concrete products of the type described in one of the preceding claims, comprising means making it possible to temporarily attach it to the vibrating table of the press, characterized in that these means comprise hooking lugs fixed on the external faces of the mold, oriented towards the bottom of said mold and extending vertically downwards from the aforementioned faces of the mold, to below the underside of said mold, and in that the lower part of each latch includes two symmetrical recesses intended to cooperate with the jaws of the press. 6. Mold according to claim 5, characterized in that the attachment tabs are fixed on two opposite faces of the mold, in pairs symmetrical with respect to the median vertical longitudinal plane of the mold. 7. Mold according to claim 6, characterized in that it comprises three pairs of hooking lugs.

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