Plastic and nonmetallic article shaping or treating: processes – Treatment of material by vibrating – jarring – or agitating... – Continuously formed or indefinite length article
Patent
1996-10-29
1998-07-14
Derrington, James
Plastic and nonmetallic article shaping or treating: processes
Treatment of material by vibrating, jarring, or agitating...
Continuously formed or indefinite length article
264 69, 425219, 425427, 425432, B28B 108, B28B 1302
Patent
active
057799539
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a method of casting concrete products with a slide casting apparatus moving along a base so that concrete mix is fed into a mould through a feeding hopper fitted above the mould and tapering downward towards the discharge opening and being moved along a path of motion deviating from the path of travel of the apparatus. The invention also relates to a slide casting apparatus for casting concrete products and comprising a mould moving in relation to a base and formed by side walls and a top plate and a feeding hopper fitted above the mould and tapering downward towards the discharge opening for feeding concrete mix into the mould, whereby the feeding hopper is provided with means for moving the hopper along a path of motion deviating from the path of travel of the apparatus.
It is previously known to cast concrete products by slide casting. In previously known slide casting machines of the extruder type compacting takes place by using feeding screws which grow thicker towards the rear end and possibly by using vibration. However, a feeding screw mechanism of this kind is relatively complicated and expensive.
It is also known to use slide casting machines of the so-called slipformer type which have no compacting feeding screws. However, in these it is necessary to use concrete mix of plastic consistency and of a relatively high water/cement ratio. A problem with this kind of plastic concrete is its poor dimensional stability immediately after casting and the known fact that the strength of the product made of plastic concrete is poorer. To improve the strength, more cement than in relatively dry concrete must be used in concrete with a high water content. A product cast of plastic concrete also tends to move along with the casting machine, and the resulting friction is abrasive on the casting base.
Such apparatus are also known wherein two feeding hoppers are located one above the other and the lower one is vibrated to compact the concrete. Such devices are described, for example, in SU Patent Publications 455 010 and 751 629.
However, a problem with such vibration of the hopper is that due to the compacting resulting from the vibration, the casting mix tends to be compacted already in the top part of the hopper, where it will arch. This prevents the concrete from flowing into the bottom end of the hopper.
The method in accordance with this invention is characterized in that the feeding hopper is moved along a controlled path of motion so that the vertical component of the path of motion of the hopper's bottom part exceeds or is equal to the vertical component of the path motion of the feeding hopper's top part, which >0 or =0. The device in accordance with the invention is characterized in that the path of motion of the feeding hopper is controlled and the vertical component of the path of motion of its bottom part exceeds or is equal to the vertical component of the path of motion of the feeding hopper's top part which >0 or =0.
In the method according to the invention it is possible to use casting mixes of a clearly stiffer consistency than in slide casting machines of the slipformer type. A lower water/cement ratio has a favourable effect on the strength and dimensional accuracy of the final product. Until now, this advantage has in fact belonged to slide casting methods of the extruder type using screws in order to create pressure and compacting. With the present invention the qualitative advantages of concrete mix of a stiffer consistency are achieved in the final product without any complicated and expensive screw machinery. With the path of motion of the movable hopper arranged in accordance with the invention, the bottom end of the hopper will also act as a part of the mould and will also compact the concrete.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention and its details are described more closely in the following referring to the enclosed drawings, in which
FIG. 1 is a schematic side view of an apparatus according to the invention,
FIG. 2 is a top view of the low
REFERENCES:
patent: 3423492 (1969-01-01), Jonell et al.
Derwent Publication BO666X/05 Jul. 1975.
Derwent Publication D3306D/15 Jul. 1980.
International Search Report (PCT/ISA/210) dated 17 Jul. 1995.
Harala Olli
Jarvinen Lassi
Sutinen Risto
Derrington James
Partek Concrete Engineering Oy
LandOfFree
Method and a device for making concrete products does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and a device for making concrete products, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and a device for making concrete products will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1878817