A system for the moulding of tubular goods

The present invention concerns a system for the moulding of tubular goods, comprising a mould having an inner mould part and an outer mould part which together define a mould cavity and an annular pouring gate upwardly.

When moulding e.g. concrete pipes in such vertical moulds, with the concrete being poured from the upper end of the mould, it is important that vibration is imparted to the poured concrete material to compact the concrete so that there will no voids in the cast concrete article. Today, the vibrations are imparted either by introducing poker vibrators down through the upper opening of the mould, or by imparting vibrations to either the inner mould part or to the outer side of the mould e.g. via the platform which carries the mould, so that the vibrations spread via the mould into the concrete.

Particularly in connection with the so-called wet mould¬ ing of concrete elements where the cast concrete element remains in its mould for a relatively long time, as the element is demoulded only after the establishment of a bonding force between the concrete particles which is greater than the friction between the cast concrete ele¬ ment and the mould, it is important to keep down the mould costs, since the costs of such moulds in mass pro¬ duction systems may be quite considerable because of the necessity of using several moulds of the same type.

This problem is aggravated today by the increasing use of tubular goods of very varying cross-sections, such as egg-shaped, four-sided and other cross-sections, which additionally increases the mould costs of a system of this type. In a system enabling switching between various

forms of basic cross-sections, it is attempted to keep down the mould equipment costs in that particularly the vibrators are re-used on the various moulds by employing removable vibrators on the outer mould part. Although the relatively expensive vibrators on this are reduced con¬ siderably in number, it is clear that the actual mould equipment is made more expensive in any event, since the mould equipment has to be provided with mounting fittings or mating flanges to connect the individual mould with the vibrators.

Today, a system is known where the mould costs are mini¬ mized in that the system is provided with a plurality of poker vibrators, which are suspended over the mould equipment, and which may be lowered down into the mould during the moulding process and be pulled up as the mould is filled. This known system is additionally adapted such that the individual vibrators may be displaced synchro¬ nously in a radial direction with respect to the mould, so that the system may be used for the moulding of circu¬ lar pipes of different diameters.

Accordingly, the object of the present invention is to provide a system for the moulding of tubular goods of the last-mentioned type, comprising moulds having an inner mould part and an outer mould part which together define a mould cavity and an annular pouring gate upwardly, said system additionally comprising a plurality of vibrators and means for lifting the vibrators from and lowering these into the mould cavity through the annular pouring gate, said vibrators being suspended from a plurality of positioning devices which are adapted to displace the vi¬ brators radially with respect to the annular pouring gate, which system, in contrast to the last-mentioned prior art, may additionally be used for the moulding of e.g. egg-shaped or four-sided pipe elements, without this

necessitating a cost-increasing adaptation of the indi¬ vidual moulds.

This is achieved according to the invention in that the positioning devices are provided with a separate control¬ lable drive unit which is adapted to displace the vibra¬ tors individually.

This makes it possible for the vibrators, which hang down from the individual positioning devices, to be positioned arbitrarily with respect to each other, so that the sys¬ tem may be used for the moulding of widely different pipe types, i.e. circular as well as egg-shaped and four-sided and other pipe types. In addition, the system is easy to adjust, thereby enabling filling of moulds which are not positioned accurately with respect to the system.

When, as stated in claim 3, an independent drive unit is provided for each drum for rolling up the flexible hose, it is ensured that the height of the individual vibrator may be adjusted independently, irrespective of the pipe geometry which is desired. It is moreover ensured that the number of vibrators may be varied, as desired.

Each positioning device may expediently comprise a spindle and an associated spindle carriage from which the vibrator hangs in the flexible hose, said positioning de¬ vices being mounted in a circle so that the spindles at one end point toward each other. When, as stated in claim 6, the drum of each positioning device is mounted on a substantially horizontal shaft, and the spindle extends completely below the drum, it is ensured that the exter¬ nal dimensions of the system may be minimized with re¬ spect to the desired maximum pipe dimension which the system must be capable of producing.

Claim 7 defines a particularly expedient embodiment, in which the drum and the spindle with associated spindle carriages are built together as an integral unit. This provides the advantage that the system may be constructed extremely flexibly, as regards the number of the individ¬ ual positioning devices in the system as well as their mutual positions.

In this connection, claim 8 defines a particularly expe- dient structure where the system has a frame with a cir¬ cular continuously extending mounting rail, and where each of the positioning devices is releasably secured to the mounting rail. This enables the individual position¬ ing devices to be positioned with different spacings from each other, thereby ensuring that e.g. the positioning devices, when moulding e.g. four-sided pipes, may be con¬ centrated around the corners of the pipes so that uniform and sufficient compaction of the concrete is obtained in these corners in the mould.

The system may additionally comprise a device for dis¬ tributing moulding material, as stated in claim 9, said device comprising a conveyor or chute which is rotatably mounted about a substantially vertical axis extending down through the inner mould part of the mould, said con¬ veyor or chute having an outlet end, means being provided for automatically displacing the distance of the outlet end from the vertical axis in such a manner that the out¬ let end follows the contour of the inner mould part dur- ing the rotation of the conveyor or the chute. This addi¬ tionally reduces the mould costs, since the individual mould does not have to be provided with chutes at the top of the mould with a view to leading the concrete down into the mould.

When, as stated in claim 10, means are provided for ad¬ justing the feed speed of the conveyor and/or the speed of rotation of the chute, the concrete will be filled ex¬ tremely uniformly in the mould, which is important in particular when moulding pipes having a greatly varying distance to the centre of the pipe, or having a varying wall thickness.

A preferred embodiment of the invention will be described more fully below with reference to the drawing, in which:

fig. 1 is a bottom view of a partially extended system of the invention,

fig. 2 is a lateral partially sectional view of the sys¬ tem of fig. 1 in an operating situation,

fig. 3 is a view of the system of fig. 2 in another oper¬ ating situation,

fig. 4 is lateral partially sectional view of part of the system of figs. 2 and 3.

Fig. 1 shows a platform 1 for a system of the invention, said platform 1 consisting of a four-sided frame element

2 which is provided at its corners with suspension points

3 constructed in a known manner such that the suspension points 3 are provided with threads, so that the platform 1 may be suspended from a parallel guide consisting of four spindles which extend down through the suspension points 3.

According to the invention, the platform 1 is provided with a set of circular mounting rails 4 and 5 which mount a plurality of positioning devices 6. For clarity, only five positioning devices 6 are shown here. As appears

from fig. 1, the positioning devices 6, which are firmly mounted on the circular mounting rails 4 and 5, may be mounted at various locations on the circular mounting rails 4 and 5 with the same or different mutual spacing.

Fig. 2 is a lateral view a system of the invention with a platform 1 of fig. 1. The system is constructed with a frame 7 provided with spindles 8 from which the platform 1 is suspended at the suspension points 3. The platform 1 may hereby be raised or lowered, as needed, so that the system may be used for moulding in moulds of different heights. Fig. 2 thus shows a sectional view of a mould 9, which is placed on a carriage 10 provided with wheels 11 which can run on the rails 12.

The platform 1 mounts a concrete silo 13 provided at its lower end with a conveyor 14 and a chute 15, which is constructed in such a manner that the chute 15 rotates about the vertical axis of symmetry 16 which extends down through the silo 13, such that the chute 15 follows the outer contour of the mould 9 when concrete is poured from the silo 13 down into the mould.

In addition, as shown in fig. 1, the platform 1 is pro- vided with a plurality of positioning devices 6, which each comprise a spindle 17 with an associated spindle carriage 18 as well as a drum 19 for the suspension of vibrators 20 from a flexible hose 21.

As shown in fig. 2, the platform 1 may expediently also be provided with a control panel 22 for an operator which can adjust the operating processor of the system. The control system will not be described in detail here, as it will be obvious to a skilled person to provide an em- bodiment of such a control system as well as algorithms for establishing it on the basis of this description.

Fig. 3 now shows the same system as shown in fig. 2 in another operating situation, where a pipe 23 is moulded in a mould 23 of another dimension than the mould 9 of fig. 2. As will be seen, the vibrators, which are sus- pended from the flexible hoses 21, are displaced inwards toward the line of symmetry 16 of the system by means of the spindles 17 and the associated spindle carriages 18.

It will moreover be seen that also the chute 15 is dis- placed inwards toward the axis of symmetry 16 of the sys¬ tem.

Thus, it will be seen from figs. 2 and 3 how the system may be adapted in a simple manner to moulding jobs with moulds, e.g. of the wet moulding type, with great variations as regards the dimensions of the moulds 9, 23 with respect to height as well as diameter.

According to the invention, the positioning devices 6, as shown clearly by fig. 4, are individually provided with a motor 24 of its own for driving the spindle 17 and thereby the spindle carriage 18, which positions the flexible hose 21 with the vibrator 20, which is not shown in this figure. The positioning device 6 thus indicates how the flexible hose 21 is rolled up on the drum 19, which, according to an expedient embodiment of the inven¬ tion, is driven by an independent motor 25. The flexible hose 21 extends from the drum out through the spindle carriage 18 and hangs vertically down from it.

Thus, the vibrator 20, which hangs down from the flexible hose 21, may be positioned in a simple and flexible man¬ ner by displacement of the spindle carriage 18 on the spindle 17 by means of the drive motor 24, so that the individual positioning devices 6, since each of them is provided with a separate drive motor 24, may be adjusted

in such a manner that the vibrators 20 hang down in a pattern which corresponds to the contour of an arbitrary mould. Thus, the system may be adapted to moulds of dif¬ ferent basic shapes, so that the moulds 9, 23 shown in figs. 2 and 3 may have a circular, four-sided, egg- shaped, oval or other cross-section.