| 摘要 |
In a process for the compaction of foundry mold making material, more specially foundry sand, using a pressing plate placed directly on the material and accelerated to a speed of up to 20 meters per second, an efficient and even compaction of the material over the full height thereof is made possible by accelerating the pressing plate in an initial phase lasting for up to 50% of the total duration of the compaction stroke progressively up to the maximum speed, then moving it in an ensuing main phase at a more or less constant speed and finally slowing it down degressively in a terminal phase, lasting for up to 30% at the most of the overall stroke time, the driving force being preferably supplied by a captive gas volume under high pressure and opposed by a hydraulic counter force, the effect of said counter force as an opposing load decreasing during the compaction stroke by rapid discharge of a hydraulic liquid.
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