Concrete casting shuttering

Claim 1

Successively raisable shuttering for use in the casting of a tapering concrete structure, comprising two mutually opposed form portions horizontally displaceable relative to each other, at least one displacing mechanism interconnecting the form portions, a raising system to which the displacing mechanism is coupled, said displacing mechanism being arranged for simultaneous operation with the raising system to displace both form portions inwardly or outwardly by a predetermined amount during each raising step of said raising system, an interposed raisable connecting part on which said two form portions are displaceably guided, synchronously driven displacing mechanisms connecting said form portions to said connecting part and operable in opposite directions for reciprocal horizontal displacement of said form portions, fluid means for operating said raising mechanism and said displacing mechanism, a pressurized fluid supply, a control device interconnecting said fluid operating means to said pressurized fluid supply for simultaneous operation of said raising mechanism and said displacing mechanism, said displacing mechanism comprising a mechanical feed mechanism connected to said fluid operating means and including several parallel screw spindles positively coupled to each other, a fluid-operated cylinder to which said screw spindles are coupled for movement in the same sense, spindle nuts on said screw spindles, and a stepping gear connecting said cylinder to said spindle nuts.