Device for die-casting of concrete goods such as block stones in

Details Device for die-casting of concrete goods such as block stones in Device for die-casting of concrete goods such as block stones in

1988-10-24

1990-09-25

Silbaugh, Jan H.

Plastic article or earthenware shaping or treating: apparatus

Sets of male-female press molds

100237, 100258R, 100258A, 2642979, 264333, 425193, 425254, 425260, 425413, 425419, 425421, 425432, 425448, B28B 108, B28B 302, B28B 1302, B30B 500

Patent

active

049590030

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a method for die-casting of concrete goods such as block stones, which are cast in a cellular casting mould by this being completely filled with concrete, whereafter a superjacent holder-on or dolly provided with mutually flush load plates having a shape corresponding to the respective subjacent cell shapes is pressed down against the concrete surface for compression of the casting material in the individual cells, preferably during vibration of the casting material from the underside of the mould. After the required compression, the dolly is lifted from the mould, and the moulded stone bodies are demoulded.
For the supply of concrete to the mould cells, a so-called filler cart is normally used, which with its bottom open is deplaced from a position in which it is placed on a fixed bottom plate underneath the outlet for casting concrete from a silo, whereby it will bring a charge of concrete over the mould and during its return movement scrape off the excess amount of concrete for which there has been no room in the cells. Thus, the mould is left with a smooth concrete surface level with the upper edges of the partitions between the cells.
Thereafter, the downwards pressing of the dolly is effected, e.g. by hydraulic power, the dolly being moved parallelly for obtaining that all the stones are compressed to the same height. Because of variations of the processing conditions and of the character of the casting concrete, the height of the stones will not always be the same, but as a height variation of .+-.2 mm is normally accepted, the result will almost always be usable anyway.
The stones must meet the requirement that their strength must be as good as possible, and that there must be only a small variation of the strength of the different stones of the production. As a certain stone strength variation inevitably occurs, the problem occurs in practice that for ensuring a desired minimum strength, it is necessary to use so much cement in the casting concrete that the weakest stones have the concerned minimum strength, whereby the other stones within the scope of variation will have an unnecessarily high cement content, i.e. generally the production requires, in reality, an unnecessarily high consumption of cement, which is a considerable disadvantage, economically as well as resource-wise.
The invention, which aims at fighting this disadvantage, is based on the consideration that the strength of the stone bodies is proportional to their density, and that thus, the strength variation will primarily be a question of density variations in the achieved result of the compression. By effecting that the density variations are equalized, the cement may thus be dosed in a better optimized manner for obtaining a cement economy in the running production, which justifies even a rather costly modification of the mould equipment.
The said stone strength variation is primarily caused by the fact that by the used simple method of casting concrete supply, an entirely uniform or compact filling of the cells is not obtained, as, locally, there may be more or less air in the concrete, and as this air only escapes by the compression and the vibration of the concrete, it is not possible in advance to effect any individual adjustment for obtaining a uniform result.
The invention is furthermore based on the observation that the normally occurring variation in the weight quantity of concrete of a uniform and good quality filled into the cells amounts to appx. 4%, which by an individually impressed compression pressure of a normal magnitude gives a resulting height difference of appx. 3 mm for typical block stones. When the products are compressed to the same height, the best filled cells will correspondingly give products having the highest density and thus the best strength. What is noticable here, however, is that the said height difference between products which have been individually compressed and thereby compressed to more or less the same density and s

REFERENCES:
patent: 2909826 (1959-10-01), McElroy
patent: 3030878 (1962-04-01), Holzer
patent: 3890413 (1975-06-01), Peterson
patent: 4142933 (1979-03-01), Graham
patent: 4545754 (1985-10-01), Scheidt et al.
patent: 4802836 (1989-02-01), Whissell

Affiliated with

Also associated with

Rating

Device for die-casting of concrete goods such as block stones in does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Device for die-casting of concrete goods such as block stones in, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for die-casting of concrete goods such as block stones in will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-326725