FI80845C - GLIDGJUTMASKIN FOER ANVAENDNING VID FRAMSTAELLNING AV BETONGELEMENT. - Google Patents

Description

80845

The present invention relates to a sliding casting machine according to the preamble of claim 1.

In a typical precast concrete sliding machine, the concrete mass is dropped onto feed screws that push the concrete under pressure onto the casting platform. The bottom side of the cross-section of the concrete element is determined by the shape of the casting base, while the other sides are determined by the side and top form plates of the sliding casting machine. The hollow channels or cavities of the element are formed by mandrel members following the feed screws. A sliding casting machine with mandrel members between the feed screws is also known.

The concrete is compacted by high-frequency vibration. In this case, the vibration is applied to the mandrel members, the mold, the mold side plates or the upper mold plate and in some cases all of these. This sliding casting machine structure is widely used, but it has e.g. the following disadvantages: the vibration method used for compaction causes strong noise, the vibration mechanism is complex and contains numerous wearing parts, and the concrete compacts differently in thin and thicker walls.

In addition, there is a prior art structure that works on the following principle:

In the first stage of the process, the sliding casting machine feeds a concrete layer on the casting base, which forms the bottom shell of the hollow core slab. In the next step, a second layer of concrete is fed between the tubular mandrel members of the sliding casting machine. The mandrel members perform a periodic longitudinal movement to improve the homogenization of the concrete mass. In addition, the mandrel members are vibrated at high frequency to compact the concrete. The sliding casting machine then feeds a third layer of concrete onto the mandrel members and finally the vibrating beam performs leveling and sealing of the top surface.

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Although the structure described above is widely used, it has e.g. the following disadvantages: the concrete has to be fed in several stages before the formwork is sufficiently full, the machine does not operate with a sufficiently rigid mass and the vibration used for compaction causes a loud noise.

Machines according to the preamble of claim 1 are described, for example, in FI application publications 840217 and 853224. Of the former, the mandrels are provided with projections, but each mandrel is continuously rotating in the same direction. In the latter, in turn, the corresponding mandrels are adapted to move back and forth only in the flow direction. In addition, it is known from FI publication 73170 that a cavity mandrel with projections is rotated back and forth about its longitudinal axis. It has been found that a solely rotating or reciprocating or merely longitudinal reciprocating movement of the mandrel does not provide a very good abrasion seal to the cast concrete.

The object of the present invention is to eliminate the disadvantages of the prior art and to provide a completely new type of sliding casting machine which is particularly suitable for the use of rigid concrete mass.

The sliding casting machine according to the invention feeds concrete into the pressurized space with feed screws or other feed devices. In the pressurized state, the mandrel or spindle members and / or the surrounding nozzle parts are shaped in such a way that their intermittent movement throughout the mass cross-section causes an abrasive movement which compacts the concrete mass. In order to effectively compact the concrete and achieve a sufficient pouring speed, the reciprocating movement of the mandrel members is combined with an oscillating, rotating movement in the direction of the longitudinal axes of the mandrel members. Thus, the concrete is not compacted by conventional vibration, but purely by the sealing provided by the combined axial and rotational movement of the mandrel members, the surfaces of the mandrels being provided with longitudinal dowels or grooves.

More specifically, the sliding casting machine according to the invention is characterized by what is set forth in the characterizing part of claim 1.

The sliding casting machine according to the invention is ideally suited for the production of concrete elements in a concrete element factory that meets modern technical requirements. The sliding casting machine can be used to produce hollow core slabs or other longitudinally profiled slabs. It is particularly suitable for use with rigid concrete masses and the compaction method does not generate noise or vibration. In addition, the machine also provides technological opportunities to manufacture new types of concrete products.

The invention will now be examined in more detail by means of the accompanying drawings, applied to a hollow core slab machine. As such, the invention can also be applied to the production of other types of profiles.

Figure 1 shows a side view of one embodiment of a sliding casting machine according to the invention.

Fig. 2 shows a schematic end view of the sliding casting machine according to Fig. 1.

Figures 3a and 3b show in sectional views two embodiments of feed screws and corresponding mandrel members.

Figures 4a and 4b show in detail the surface structure of two different embodiments of the mandrel member, respectively.

Figure 5 shows the mixing process in the concrete mass caused by the frictional movement generated by the reciprocating rotational movement of two adjacent mandrel members.

The machine according to Figures 1-5 comprises a concrete feed hopper 1, from which the concrete mass flows to the feed screw 2. The feed screws 2 ensure an even supply to the concrete mass and the desired pressure.

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According to Figure 1, the feed screws are arranged in succession with the mandrels or spindles 3 and 4, but the device can also be implemented by placing the screws 2 to feed from above to obliquely downwards. The device can also be implemented by replacing the feed screws with an alternative pressure generating device. A sealing part 9 is connected to the discharge end of the feed screws 2 in the sliding machine, which prevents the penetration of the concrete mass between the rotating feed screw 2 and the periodically clockwise / counterclockwise rotating mandrel member 3. The seal structure itself can be of any known type: a maze seal, a flexible rubber seal, a lip seal or the like.

The first actuators 7 attached to the body 17 cause the feed screw 2, the mandrel member 3 and the extension assembly 4 to move longitudinally back and forth in a manner known per se. Adjacent mandrel combinations can be moved synchronously in opposite directions. When the second actuators simultaneously cause the mandrel members 3 to rotate back and forth around the axes via the shaft 19 (Figs. 3 and 3b), a helical combined movement of the pins 10 (Fig. 4a) or the grooves 10 · (Fig. 4b) is achieved. This movement has a very effective sealing effect on the surrounding concrete.

In the embodiment according to Figure 3a, the mandrel member 3 and its extension 4 rotate together.

In the embodiment according to Figure 3b, the extension 4 is independent of the mandrel member 3 and can be completely non-rotating or can rotate e.g. with the feed screw 2. Such a structure requires an additional hollow shaft 22.

The longitudinally ribbed and shaped part of the shaping member 3 follows the seal 9 in the direction of the concrete flow. The exceptional cross-sectional profile of the dowel is preferably triangular (Figure 2) or semicircular.

II

5 80845 second (Figure 5). When the rotational movement of the mandrel members 3 about their longitudinal axes is arranged to vibrate periodically, an internal friction is applied to the concrete, which, under pressure, compacts the concrete.

The length of the mandrel members and the height of the dowels 10 affect the degree of deformation, and in the thin parts of the concrete elements it is preferred to use a less shaped studded part with a shorter mandrel member 3. Correspondingly, in the more massive parts of the concrete element, a stronger dowel and longer dowel members can be used.

A similar effect can be achieved with the embodiment according to Fig. 4b, in which the cylindrical surface of the mandrel member is provided with longitudinal grooves 10 instead of dowels. The grooves are wider and deeper at the end 2 of the feed screw of the mandrel member, tapering towards the end 4 on the side of the extension piece.

The shape of the longitudinal dowel may differ from the above options. The longitudinal dowel can also be a row of thin, parallel-mounted steel strips, the heights of which vary according to the thickness variations of the sliding casting product, so that the strip-like longitudinal dowel is lower for a thin cross-section and correspondingly higher for a more massive cross-section.

For each reciprocating stroke of the rotational movement of the punched mandrel member 3, the most recommended amplitude in the direction of this longitudinal axis is about 1 to 2 mm at a frequency of 10 to 1000 strokes / s (Hz). Of course, the proposed setpoint can be changed. Part 3 is followed by an extension 4 which gives the cavity this final shape. The cross-section of the mandrel member 3 and its extension 4 can always vary according to the cross-section of the desired cavity. In Fig. 2 the cross section is circular and in Fig. 5 it has the shape of a TV screen.

The reciprocating rotational movement of the mandrel members 3 and their extensions 4 is effected by the drive device 7 '.

The side mold plates 11 form the edge profile of the element.

The apparatus is housed in a frame 17 which moves on support wheels 8 on a casting base 18. Naturally, the equipment can be supplemented in some respects by conventional high-frequency vibration, e.g. with external vibrators arranged in the upper mold plate 5.

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Claims (10)

A non-slip casting machine for the production of concrete elements, in particular hollow elements, movable relative to the casting base (18), comprising - a hopper (1), - at least one feeder (2), e.g. a feed screw, for applying pressure to the concrete to be poured, and ) of the next mandrel member (3, 4) having a jacket surface with deflections (10), characterized in that - the machine comprises drive means (7, 7 ', 19) for moving the mandrel member (3) in simultaneous reciprocating axial motion and reciprocating rotational motion and - the deviations (10) are elongate and substantially parallel to the axis of the mandrel member (3). A sliding casting machine according to claim 1, characterized in that each feeder (2) and its mandrel member (3, 4) are adapted to make a common, simultaneous axial movement. Sliding casting machine according to claim 2, characterized in that each mandrel member (3, 4) comprises a first mandrel part (3) immediately following the feed screw (2) and an extension (4) directly following the first mandrel part (3). Sliding casting machine according to claim 3, characterized in that the elongate deflections comprise ridge structures (10), such as dowels, which extend substantially over the entire first mandrel part (3). θ 80845 A sliding casting machine according to claim 4, characterized in that the dowels (10) extend radially from the mantle surface of the first mandrel part (3) of each mandrel member and whose height from the mantle surface decreases towards the extension (4). Sliding casting machine according to Claim 4, characterized in that the cross section of the dowels (10) is substantially triangular or hemispherical. A sliding casting machine according to claim 3, characterized in that the elongate deviations comprise grooves (10) extending substantially over the entire first mandrel part (3). 7 80845 Sliding casting machine according to Claim 7, characterized in that the depth and cross-section of the grooves (10) decrease towards the extension (4). Sliding casting machine according to Claim 5, characterized in that the dowels (10) comprise thin steel strips. A sliding casting machine according to claim 1, characterized in that the elongate deflections (10, 10) are evenly distributed on the jacket surface of said part (3) of the mandrel member (3, 4). Il 9 80845