发明名称 Manufacture of pre-stressed concrete railroad ties
摘要 Prestressed concrete railroad ties are formed in molds which are supported by existing track near the area where they are to be installed. Each mold will form a number of ties. Reinforcement strands are located within a plurality of longitudinally spaced molds. Concrete is then poured into the molds and the ties are formed bottoms up in the molds. A group of ties are simulatenously removed from a given mold by a special extractor which first simultaneously clamps the reinforcing strands extending outwardly from a given mold, and then lifts the strands as a group from the mold by a suitable crane. Preferably the center of gravity of ties is spaced from a pivot point which will cause 180 DEG rotation locating the ties in upright position to be loaded on a railway car or other vehicle to take them to the site where they are to be installed. BACKGROUND OF THE INVENTION
申请公布号 US4773840(A) 申请公布日期 1988.09.27
申请号 US19870110739 申请日期 1987.10.21
申请人 JANTZEN, STEVEN L. 发明人 JANTZEN, STEVEN L.
分类号 B28B13/06;B28B23/06;E01B3/34;(IPC1-7):E01B3/34;B28B13/04 主分类号 B28B13/06
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