Method and equipment for the compacting of concrete

Method and equipment for compacting of concrete mix when concrete products are being cast by means of a continuous method. The concrete mix is carried from the feeder device (4) forwards by means of an endless transfer unit. The compression required for the compacting of the concrete mix is produced by means of a roll (1) pressed against the transfer face (2). The compression is directed at the concrete mix by the intermediate of rigid plates (2) of a caterpillar band constituting the transfer unit, which plates are pressed against the concrete mix by means of two or more support rolls (1).

The present invention is concerned with a method for the compacting of 
concrete mix when concrete products are being cast by means of a 
continuous method, whereat the concrete mix is carried from the feeder 
device forwards by means of an endless transfer unit and the compression 
required for the compacting of the concrete mix is produced by means of a 
roll pressed against the transfer face. The invention is also concerned 
with equipment for carrying out the method, which equipment is provided 
with a feeder device for feeding the concrete mix and with a compression 
member for compacting the concrete mix. 
In the manufacture of concrete products, it is known in prior art to use a 
so-called band-rolling method, in which the concrete mix is pulled between 
steel bands. The mix is compacted by means of a pair of rolls placed at 
both sides of the bands. At the rolls, a sudden compression, based on very 
high pressure, is produced. It is a difficulty involved in the band 
rolling that the sudden compacting taking place at the rolls produces 
internal cracks and cavities in the concrete, because of which the mix 
must have a very high content of cement and a small particle size. 
A method is also known for the manufacture of board-shaped concrete 
products so that the mix placed in the mould is compacted by means of a 
vibrator beam. 
The method of the present invention is mainly characterized in that the 
compression is directed at the concrete mix by the intermediate of rigid 
plates of a caterpillar band constituting the transfer unit, which plates 
are pressed against the concrete mix by means of two or more support 
rolls. According to a particularly favourable embodiment, the support 
rolls are vibrated. The equipment of the invention is mainly characterized 
in that the compression unit consists of a caterpillar belt consisting of 
rigid plates and of support rolls pressing the plates against the mix. 
Advantages of the method of compacting in accordance with the present 
invention as compared with the prior-art methods, either vibration alone 
or rolling by means of round rolls, are: 
simultaneous operation of the rolls as generators of pressure, as conveyors 
of concrete mix or compacting machine, and possibly as vibrators, 
easy adjustability of the compression pressure and of its distribution by 
means of the support rolls; adjustment may also be performed during the 
process, whereby uniform quality of the compacted concrete is ensured and 
micro-cracking and other defects of the concrete are avoided, which 
defects are readily produced, e.g., on ordinary compacting by means of 
rolling, 
efficiency of the compacting, because the pressure and the intensity of 
vibration can be combined in a way suitable for the concrete mix and for 
the product, 
low noise level as compared with conventional vibration, because by using 
pressure, it is possible to reduce or even to eliminate vibration which 
causes noise, 
the concreting speed can be varied by accordingly adjusting the rate of 
compacting by changing the position of the support rolls.

The equipment is provided with two caterpillar belts consisting of belt 
plates 2, circulating around transfer wheels 3, fitted opposite each 
other, and supported by means of roller-shaped support rolls 1. The 
support rolls may be vibratable. Their spacing is preferably at the 
maximum one half of the width of the plates 2, whereat, in all positions 
of the caterpillar belt, there are always at least two support rolls 
positioned against each plate. The transfer wheels 3 are provided with 
pins 7, which fit into holes provided at the ends of the plates 2. 
The support rolls 1 and the transfer wheels 3 are, at their ends, supported 
against each other or against the frame (not shown in the drawing) of the 
compacting device so that the space between opposite support rolls and, 
consequently, also the space between the caterpillar belts can be 
adjusted. The support of the support rolls may be resilient, e.g., by 
means of springs or electrically controlled cylinders. 
At one end of the caterpillar belts, a feeder device 4 is provided. The top 
portion of the feeding opening of the feeder device, which opening opens 
itself towards the caterpillar belts, is connected with a horizontal 
adjusting plate 5, whose height can be adjusted and which may also be 
provided with slight vibration. At the opposite side of the adjusting 
plate, there is the mix-feeding bottom 6. The feeding bottom may also be 
provided with additional vibration. 
The concrete mix is fed into the compacting device out of the feeder device 
4 and the quantity of mix is controlled by means of the adjusting plate 5. 
The adjusting plate 5 may also be vibrated slightly. When the transfer 
wheels 3 revolve in the direction indicated by the arrows, the plates 2 of 
the caterpillar belts carry the concrete mix forwards, or alternatively, 
they carry the compacting machine in the opposite direction. The concrete 
mix is subjected to pressure by means of the plates 2 supported by means 
of support rolls 1, and possibly additionally to vibration, generated, 
e.g., via the support rolls. Thus, when the plates 2 move on the rolls 1, 
they at the same time compact the concrete mix and force its faces into a 
specified shape. 
The thickness of the mix layer that is being compacted can be adjusted by 
changing the space between opposite supports rolls 1. When resilient 
suspension of the plates 2 of the caterpillar belt is used, the pressure 
at the plates is equalized. 
The compacting caterpillar belts may act upon the mix to be compacted to 
board form either from one side against the concreting base or from both 
sides, as is shown in the drawing. If one-sided compacting is used, a 
concreting base is used in stead of the mix-feeding bottom 6. When pieces 
of rectangular section are produced, it is possible to use two pairs of 
rolls placed perpendicularly to each other and at the distances of the 
dimensions of the sides of the beam from each other. Beams with sections 
of six or more angles may also be produced by using three or more pairs of 
rolls. 
The plates of the caterpillar belts may have smooth compacting faces, or 
these faces may be patterned, grooved or otherwise profiled in any desired 
way, in which case they also determine the shape of the face or faces of 
the product that is produced. If it is desirable to eliminate the trace of 
the joint between the plates of the caterpillar belts off the concrete, it 
is possible to use a smoothing plate on the caterpillar belt. If it is 
desirable to provide the product, e.g., with cavities, the device may be 
additionally provided with parts that form the cavities, which parts may 
also be provided with vibration.