EP0539305A1 - Mould for vibrating and forming concrete products such as breeze-blocks, paving blocks or kerb stones - Google Patents

Abstract

According to the invention, the mould comprises, in combination: - wear plates (5, 6) having a purely parallelepipedal shape, that is to say plates not including any specific means for positioning them with respect to one another in the frame (3), and - as the clamping means, at least one part (15) in the shape of a wedge, capable of bearing against the frame (3) of the mould (2) on the one hand and against the wear plates (5, 6) on the other hand. <IMAGE>

Description

The present invention relates to a mold for the vibration molding of concrete products, such as breeze blocks, pavers or curb elements.

Such products are produced, in a manner well known per se, by means of a mold in the form of a box and a pestle for compacting the concrete in the mold. The mold is normally placed on a wooden tray, itself positioned on a vibrating table directly above the tamping pestle. A filling drawer slides and rubs on the flat and horizontal upper wall of the mold, which constitutes a wear plate. This drawer moves between two extreme positions, one where it is positioned under a concrete distribution hopper and the other where it is positioned above the mold to fill the cavities of the latter. After the concrete has flowed into the mold and the drawer has been removed, the pestle, which consists of checkers or knives having, apart from play, a shape complementary to that of the mold cavities, then descends into said cavities while the table vibrates, exerting a predetermined packing force depending on the type, height or shape of the products to be obtained. After compaction, the mold rises to unmold the products, which are then evacuated to a drying area.

Known molds have a rectangular frame in which are placed wear plates resistant to repeated friction of the pestle and the material during vibration molding. These plates delimit the external contours of the elements to be molded: some of them are arranged against the internal faces of the frame, of which they constitute the lining, and others, generally arranged transversely with respect to the longitudinal axis of the frame, constitute partitions separating the different compartments of the mold. In each compartment delimited by the partitions, are placed cores carried by support bars bearing on the edges of the frame. These cores also act as wear plates.

In order to increase the life of the mold, the wearing parts are generally subjected to a heat treatment prior to their assembly which gives them maximum hardness.

To assemble the various component parts the mold, the most commonly used technique consists of welding the wearing parts to the mold and between them.

This technique has two drawbacks. On the one hand, during welding, the parts tend to deform under the rise in temperature, which involves straightening them manually after they have cooled and results in a loss of precision in the assembly. On the other hand, the welding of heat treated parts is delicate. In case of cementation, the cemented layer must be removed. In addition, the parts are locally soaked with the appearance in the heat affected zone of microcracks and cracks detrimental to their good resistance to vibrations.

To remedy these drawbacks, a second technique consists in screwing or bolting the wearing parts on the frame. This technique is long and very expensive to implement because of the drilling and machining that it is necessary to perform, as well as the very precise positioning required by the installation of screws or bolts.

Another technique consists in assembling the parts by gluing, in particular using epoxy resin. However, this technique involves the design and manufacture of complex parts with appropriate anchoring surfaces and a surface finish. As a result, the industrial manufacture of the mold using this technique is difficult.

Yet another technique, described in patents GB 266,373 and FR 2,104,328, consists in providing wear plates which are not permanently fixed to the mold but which are clamped against one another between bearing surfaces located on one side of the mold and clamping screws located on the opposite side of the mold.

These screws have the disadvantage of providing, under the conditions of practical use of such a mold, only a limited tightening force involving, to ensure perfect holding in position of the wear plates when the pressure is exerted. of the pestle and the vibrations, to provide additional means of positioning in the wear plates with respect to each other, such as lateral tabs or pins which can be engaged in corresponding recesses or grooves, as described by these aforementioned prior patents.

The arrangement of these means leads to drilling, cutting and machining in the wear plates, which is long, difficult and very expensive to implement, as has previously been indicated.

The present invention aims to remedy all of these drawbacks.

The mold which it concerns comprises a rectangular frame, wear plates, some of which double the internal walls of the frame and others of which form partitions making it possible to divide the frame into compartments of dimensions corresponding to those of the elements to be produced, bearing surfaces and clamping means able to clamp the wear plates against the bearing surfaces so as to immobilize said plates in the frame.

• des plaques d'usure ayant une forme purement parallélépipédique, c'est-à-dire ne comprenant pas de moyens spécifiques pour leur positionnement les unes par rapport aux autres dans le cadre, et
• à titre de moyens de serrage, au moins une pièce en forme de coin, apte à appuyer contre le cadre du moule d'une part et contre les plaques d'usure d'autre part.

According to the invention, the mold comprises, in combination:

• wear plates having a purely parallelepiped shape, that is to say comprising no specific means for their positioning relative to each other in the frame, and
• as clamping means, at least one wedge-shaped part, capable of pressing against the mold frame on the one hand and against the wear plates on the other hand.

Thanks to the invention, the wear plates and the partition walls can be assembled to the mold without deterioration of their surface and without carrying out complex and costly machining.

In addition, there may be some play between the end of the partitions and the wall of the side members or crosspieces without prejudicing the shape of the mold cavities. The ends of the partitions do not therefore require very precise cutting and machining.

In addition, the interchange of partitions and wearing parts is particularly easy and quick to carry out. The same frame can therefore be reused many times and with partitions or wear plates of different types to be used for molding elements of different shapes.

Preferably, in the case where the frame has a long length, the abovementioned bearing surfaces are replaced by wedge-shaped parts acting on the partitions and on the wearing parts in the direction opposite to that in which the one or more other parts act on them. The clamping force exerted is thus reinforced.

According to a preferred embodiment of the invention, recesses are arranged opposite one another in the internal face of the side members or crosspieces, each recess being delimited, by a on the one hand, by a shoulder delimiting a bearing surface for the wear plates and, on the other hand, by a shoulder delimiting an oblique surface inclined towards the outside with respect to the recess, against which the corner piece is intended to support and slide.

• Figure 1 en est une vue en perspective ;
• Figure 2 est une vue de dessus d'un cadre délimitant l'empreinte du moule, selon une première forme de réalisation ;
• Figure 3 est une vue en perspective, de détail et à échelle agrandie, d'éléments constituant le moule ;
• Figure 4 est une vue en coupe selon IV-IV de figure 3 ;
• Figure 5 est une vue similaire à la figure 3, du moule selon une autre forme de réalisation ; et
• Figure 6 est une vue de dessus du cadre du moule représenté à la figure 1.

In any case, the invention will be clearly understood with the aid of the description which follows, with reference to the appended diagrammatic drawing, representing, by way of nonlimiting example, a preferred embodiment of the mold which it concerns.

• Figure 1 is a perspective view;
• Figure 2 is a top view of a frame defining the mold imprint, according to a first embodiment;
• Figure 3 is a perspective view, in detail and on an enlarged scale, of elements constituting the mold;
• Figure 4 is a sectional view along IV-IV of Figure 3;
• Figure 5 is a view similar to Figure 3, of the mold according to another embodiment; and
• Figure 6 is a top view of the mold frame shown in Figure 1.

FIG. 1 represents a mold 2 used for the vibrating molding of concrete products, such as concrete blocks, paving stones or sidewalk edge elements.

The mold 2 comprises a rectangular frame 3, more particularly visible in FIGS. 2 to 6, housed inside a box 4. In the frame 3, are arranged parallelepipedic wear plates 5,6 delimiting the external contours elements to be molded: some, 5, of them, are arranged against the internal faces of the frame 3, of which they constitute the lining, and others, 6, generally arranged transversely relative to the longitudinal axis of the frame 3, constitute partitions separating the different compartments of the mold 2. In each compartment delimited by the partitions 6, are placed cores 7 carried by support bars 8 bearing on the edges of the frame 3. The wear plates 5, the partitions 6, the cores 7 and the bars 8 are flush with the horizontal upper surface 4a of the box 4.

Figures 2 to 5 show a frame 3 according to a first embodiment, consisting of beams 3a and 3b sleepers assembled to each other. According to this embodiment of this frame, the partitions 6 are arranged perpendicular to the side members 3a which each comprise, formed in their internal face, a recess 10. Each recess 10 is delimited, on the one hand, by a shoulder 11 delimiting a surface 11a perpendicular to the longitudinal axis of the spar 3a and, on the other hand, by a shoulder 12 delimiting an oblique surface 12a inclined towards the outside with respect to the recess.

On the side of the oblique surfaces 12, each recess 10 receives a part 15 of trapezoidal cross section. The part 15 has an oblique face 15a of the same inclination as the bearing surface 12a and a second oblique face 15b, opposite the face 15a, having the same inclination as the face 16a, inclined towards the inside of the recess 10 , of an intermediate support piece 16. The face 16b of the piece 16 opposite the face 16a is perpendicular to the longitudinal axis of the spar 3.

The part 15 is pierced with several threaded bores 20, formed along its median longitudinal axis, in which can be engaged several screws 21 passing through holes 22 formed in the spar 3a and whose head 21a is in abutment against the external face of the beam 3a.

In addition, the wear plates 5 intended to double the side members 3a have a parallelepiped shape and a length equal to the distance which must separate the partitions between them.

As shown in FIG. 2, the recesses 10 are intended to receive the wearing parts 5 and the ends of the partitions 6, the partition 6 furthest from the part 15 bearing against the surfaces 11a delimited by the shoulders 11 The wear plates 5 and the other partitions 6, for their part, bear against one another.

The screwing of the screws 21 causes the part 15 to move perpendicular to the longitudinal axis of the beam 3a and, therefore, the production of a large clamping force making it possible to tighten the wear parts 5 and the partitions 6 between the part 15 and the bearing surfaces 11a, so as to ensure their perfect retention in position when the pressure of the pestle and the vibrations transmitted by the press is exerted.

Thus, the wear plates 5 and the partitions 6 can be assembled to the mold 2 and held very securely in the frame 3, without carrying out welds, and therefore without deterioration of their surface coating, and without carrying out complex machining and expensive.

In addition, the interchange of partitions 6 and wearing parts 5 is particularly easy and quick to achieve by loosening the screws 21. The same frame 3 can therefore be used many times and with partitions 6 and wear plates 5 of different types to be used for molding products of different shapes.

Figure 6 shows an alternative embodiment of the invention for molds 2 of great length. In this variant, the recesses 10 are each delimited by two oblique surfaces 12a and parts 15, 16 are provided on either side of the partitions 6 and wearing parts 5. Thus, these wearing parts 5 and partitions 6 are clamped in two opposite directions.

FIG. 5, for its part, represents another alternative embodiment of the invention in which a cover plate 30 can be provided to facilitate the positioning and the maintenance of the wearing parts 5 and of the partitions 6 in position the workpiece tightening time 15.

Claims (3)

1 - Mold for the vibrating molding of concrete products, such as concrete blocks, paving stones or sidewalk edge elements, comprising a rectangular frame, wear plates, some of which double the internal walls of the frame and others of which form partitions making it possible to divide the frame into compartments of dimensions corresponding to those of the elements to be produced, bearing surfaces and clamping means capable of clamping the wear plates against the bearing surfaces so as to immobilize said plates in the frame, characterized in that it comprises, in combination: - wear plates (5,6) which have a purely parallelepiped shape, that is to say not comprising additional positioning means relative to each other in the frame (3), produced in particular by machining , and - As clamping elements, at least one piece (15) in the form of a wedge, capable of pressing against the mold frame on the one hand and against the wear plates (5,6) on the other hand. 2 - Mold according to claim 1, characterized in that the bearing surfaces (11a) are replaced by parts (15) in the form of a wedge acting on the partitions (6) and on the wearing parts (5) in direction opposite to that in which the other parts (15) act on them. 3 - Mold according to claim 1 or claim 2, characterized in that recesses (10) are arranged opposite one another in the internal face of the side members (3a) or crosspieces (3b) of the frame ( 3), each recess (10) being delimited, on the one hand, by a shoulder (11) delimiting a bearing surface (11a) and, on the other hand, by a shoulder (12) delimiting an oblique surface (12a ) inclined towards the outside with respect to the recess (10), against which the wedge-shaped part (15) comes to bear.

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