FI81520B - Arrangement for casting concrete products, especially hollow slabs as extruded castings - Google Patents

Description

, 81520

Apparatus for sliding casting of concrete products, in particular hollow core slabs. - Anordning för gjutning av betongprodukter, speciellt hälplattor sorti glidgjuten.

The invention relates to a device for sliding casting of concrete products, in particular hollow core slabs, in which concrete is guided by means of at least one feed screw under pressure into a sealing part formed by a casting base, side plates and top plate. and the outer surface of the hollow mandrel extending as an extension of the incoming cylindrical neck of the hollow mandrel feed screw is at least partially increasing in the feed direction of the screw.

In particular, sliding casting methods are already known for producing hollow core slabs from concrete, in which the concrete is continuously pressed from the hopper into the mold by means of a screw conveyor and the concrete is compacted by a high-frequency vibrator in contact with the mold walls or core elements. The disadvantage of these methods is that the concrete compacts unevenly and insufficiently, especially if the wall thicknesses of the building element vary. In addition, the noise generated is considerable. In addition, due to the vibrators, the manufacturing equipment becomes complicated in structure, because the transfer of the energy of the vibrators to the mold and the cores requires expensive constructions.

In addition, sliding methods are known in which the concrete is fed in layers into the mold under pressure and compacted. In this case, the disadvantages are the limited use possibilities, in particular with regard to the achievable structural height of the building element, and the lower strength of the concrete. These methods also use high-frequency vibrators for compaction, which cause high noise levels.

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Because high-frequency vibration has been found to have several disadvantages in compacting concrete, sporadic methods for compacting concrete have also been recently developed. In high-frequency and shock vibration, the main principle of compacting concrete is by dynamic means and by utilizing the elasticity of the mass particles to move them with each other and thus the concrete to compact. In infrequent methods, the compaction of concrete takes place mainly by means of mechanical mutual displacements of the pulp particles. In this case, the compaction movements are also typically long, in which case a small number of movements is sufficient for compacting the concrete. These methods are characterized by low noise.

Mechanical, sparse sealing has also been applied to the manufacture of hollow core slabs. As an example, in the solutions of applications 831606 and 840217, a feed screw is used for feeding the concrete and displacements of the shaping member transverse to the flow direction of the concrete for compacting the concrete.

In the method according to patent application 853224, the compaction takes place by reciprocating the concrete in an arbitrary direction.

The reciprocating movement applied to the concrete is also known e.g. patent applications 831605 and 813555 and 813556.

In SU patent publication 766860, concrete flows out of the hopper with its own weight and has a piston instead of a feed screw, as a result of which this device does not provide a very good seal.

All of these known methods and devices have disadvantages such as that the compaction takes place only in a certain direction and / or the concrete is moved back and forth, whereby the already compacted concrete is unnecessarily worked. Thus, 3 81520 does not achieve a sufficient degree of compaction and additional wear occurs on the machine parts.

The object of the present invention is to eliminate the above-mentioned problems and to implement an apparatus for manufacturing cavity elements or the like, preferably of concrete, and to achieve a high and controlled sealing performance at a low noise level while reducing the wear of the sealing parts.

According to the invention, this object is solved in this way, and the device according to the invention is characterized in that the outer surface of the hollow-mandrel end of the feed screw is formed to be at least partially tapered in the feed direction of the screw.

In the device according to the invention, frictional compaction movements acting in several directions are applied to the concrete in a pressurized state, movements in different directions are applied to the same area, concrete is subjected to substantially parallel displacements without reciprocating movements and movements (displacements) in different directions can be controlled. The device can achieve even higher strengths and dimensional accuracies of the elements, especially in products such as a hollow element or other sliding-molded profiles.

The invention will now be examined in more detail with reference to the accompanying drawings.

Figure 1 shows the production of hollow core slabs according to the invention in a schematic side view (longitudinal section) of the device.

Figure 2 shows a schematic cross-section of the machine for making hollow core slabs according to the invention, seen from the end of the machine 4 81520, the device being adjusted to produce three-hole hollow core slabs.

Figure 3 shows a cross-section of the sealing area of the concrete.

Figure 4 shows a cross-section of a concrete sealing area with different mass cross-sections.

In the embodiment of the invention according to Figures 1 and 2, the hollow core slab manufacturing apparatus is built on a frame 1. From the pulp tank 2, the concrete flows down to the feed screws 3. There are one or more feed screws and they transfer the concrete to the sealing part 10. The feed screws can also be used to create the desired pressure in the concrete to control the sealing. In the sealing part, the concrete is formed into its desired shape by means of side panels 11 and a top plate 12 on the casting base 18 by means of a hollow mandrel 4, which may be one or more. The shape of the cavity can be calibrated by means of the cavity sleeve 5. The feed screws are driven on the rounding shafts 6 and by means of the screw actuators 8. The sealing movement of the mandrels 4 is effected by means of drawbars 7 and a mandrel drive 9. By means of the top plate drive device 13, it is also possible, if necessary, to friction compact the concrete in the sealing part 10 with the top plate. It is also possible to arrange the drive device in the side plates 11, by means of which they perform rubbing compaction. The casting machine moves at the edges of the casting platform by means of the thrust caused by the feed screws and on the support wheels 14. In this case, a finished product 19 is formed on the mold, which in the form shown in the figures is a three-hole hollow core slab.

Figures 3 and 4 show in more detail the method according to the invention and its application in a hollow core plate machine. In the sealing section, the concrete is subjected to the desired pressure by means of a feed screw, a hollow mandrel and a top plate, and these elements also cause sealing displacements in the concrete in a certain direction, i.e. a flow in the desired direction.

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The feed screw 3, which moves the concrete to the sealing point 10, provides the concrete with a circumferential flow of the screw. This is best effected by making the end of the screw 3 a converging cone which acts as a push cone 15. The length a of the push cone and the magnitude of its angle of inclination can influence the vortex flow generated by the screw to the proportion of the component in the seal. A mandrel cone 17 is formed in the hollow mandrel 4, which acts as a counter-cone to the concrete flow. The curvature of the mandrel makes a reciprocating movement approximately in the axial direction of the screw, in which case in the sealing section 10 the displacements in the direction of flow as well as the transverse transitions with respect to the direction of flow are obtained in the concrete. The length b of the mandrel cone 17 and the magnitude of its angle of inclination can be used to influence the relative size of the different flow components of the concrete and thus the degree of compaction. In this way an internal displacement 1. section is introduced into the concrete in three space directions x, y, z, of which the longitudinal displacement x arises from the opposite components of the mandrel cone and screw in the circumferential direction.

This three flow directions to the concrete can be seen between the screw pushing cone 15 and the mandrel cone 17 in the entire sealing part 10. The sealing efficiency can further be influenced by the sealing movement of other parts as in the figure by means of the upper plate 12.

Figure 4 shows a solution in which different wall thicknesses d2 and c2 are formed in the concrete and the finished element. The uniform sealing of these can also be effectively effected by the device according to the invention by making the mandrel cone of different dimensions and shapes at the respective points d1 and d.

β 81520

The strength and orientation of the seal are further affected by the length and depth of the mandrel neck 16. The length and relationship of the screw working cone 15, the mandrel neck 16 and the mandrel cone can affect the sealing time, so that the sealing event can be affected by this fourth dimension.

It is typical in the device according to the invention that several transitions in different directions are applied to the concrete in one sealing part and are not made in different successive stages, whereby the already sealed sections of concrete are broken.

In addition, the device is characterized in that the concrete is not moved back and forth but is given a parallel advancing flow and the necessary sealing displacements from this flow direction in all directions x, y, z of space.

In addition to this, it is typical in the device that the lengths of the screw push cone, the mandrel neck and the mandrel cone and their sizes are used to influence the different compaction degrees of the concrete and the compaction time.

In previous devices, it has been common for a concrete product to have a completely different strength in different directions in the product. With the device according to the invention, uniform strength can be achieved in all directions of the product.

Claims (5)

1. Device for casting concrete products, especially slabs (19) as sliding cast, in which device the concrete is guided by means of at least one feeder screw (3) under pressure to a sealing member (10) formed by a casting base (18), side panels ( 11) and an upper disk (12), arranged in the sealing member (10) as an extension to the feeder screw (3), partially in the feed screw (3) and axially movable to the feeder screw (3), and the extension to The cylindrical neck (16) of the pouring mandrel (4) into the cylindrical neck (16), the outer surface of the pouring mandrel (4), at least partially grows, characterized in that the outer surface of the feed screw (3) located at the end of the pouring mandrel (4) narrows at least partially. (3) feed direction. 2. Device according to claim 1, characterized in that the feeder screw (3) closest to the pouring mandrel (4) is additionally provided with elevations to effect the eddy flow component. 3. Device according to claim 1 or 2, characterized in that the growth of said extension to the outer surface of the neck mandrel (4) is different on different sides of the mandrel (4). Device according to any of claims 1-3, characterized in that the upper plate 12 is arranged in the axial direction of the feed screw (3) reciprocally movable and it has a surface which at the sealing part (10) in the feed screw (3) approaches the axis of rotation of the feed screw. 5. Device according to any one of claims 1-4, characterized in that the sizing is adapted to the cone (3) of the feeder screw (3), the neck (4) of the mandrel (4) and the cone (17) of the mandrel (4) 81 520 9. so that a sealing time of the desired measured is achieved.