GB734751A - Apparatus for forming pre-cast slabs from concrete or similar material - Google Patents

Abstract

734,751. Moulding concrete slabs &c. ABBOTT, F. W. May 29, 1951 [March 1, 1950], No. 5188/50. Class 87 (2). Apparatus for casting concrete or cement-breeze slabs comprises, Figs. 1 and 3, two stationary longitudinal parallel side plates 2 that form the sides of moulds; transverse division plates 8 that form the ends of the moulds and are mounted on conveyer chains 5 running over sprockets 6, the upper reach of the chains travelling from right to left; flat pallets 3 that form the bottoms of the moulds and are pushed along tracks 4 by the plates 8; an open-bottomed hopper 1 from which concrete &c. is delivered into the moulds, the front edge 9 of the hopper strickling the concrete; and automatically-operated means for tamping the concrete in the moulds, this means comprising a flat-faced tamper 12 which is operated to ram down the concrete with repeated blows and at the same time to move over the concrete in the same direction as the concrete but at a quicker speed so as to force some of the concrete towards the front edge of the pallet, whereby a slab of even density is formed. The tamper 12 is curved up at its leading edge 18 and is extended forward for pivotal mounting on a shaft 13. The tamper is depressed repeatedly by a cam 14 and raised by a spring 17. The mould sides are ribbed and grooved to provide grooved and ribbed slabs, Fig. 2 (not shown), or may be plain. Automatic vibrators may act on the mould sides 2 or on the conveyer or a pallet. The upper surface of the concrete may be acted on by a vibrator. The tamped material may be finished off by a roller. A pressure roller may be used before the tamping device 12. Fig. 4 shows a modified tamper pivoted at 19a and raised by spring 21. Fig. 5 shows a modified machine in which the tamper 25 has rollers 26 working in side guides 27 and is operated by side eccentrics 14a and arms 15a. The leading end of this tamper travels in a horizontal plane or may be given a slight lift. The division plates 8 have ribs 23 and grooves 24. The side plates 2 may be plain or ribbed and grooved. Fig. 7 shows another tamping device comprising tampers 28 carried by travelling endless chains 29 the rear sprockets 30 of which raised and lowered by levers 31 operated by eccentrics. The chains and/or tampers may run in or engage guides 32. The chains may be tensioned by a spring-loaded jockey roller 33. A finishing roller may be located near the delivery point.