GB572390A - Improvements in the production of pre-stressed reinforced concrete sleepers and similar beams - Google Patents

Abstract

Parallel reinforcing wires are placed in position in production lines and tensioned, a mould is assembled around the wires at the mould-filling station, and the mould is filled with concrete and then slid along the production line (and along the wires). The mould can slide by reason of the provision of slotted end-plates 23 thereon (see Specification 572,387). The reinforcing wires are stretched between upright pedestals extending along the line. The mould-filling station may be at one end of the line, the moulds being assembled around the wires, filled, vibrated, and slid in turn along the wires to the other end, where the concrete is allowed to set; at the setting position the concrete may be vibrated again. Alternatively, the mould-filling station may be at a mid-position in the line, the filled moulds being slid along the wires in either direction. The moulds may run on rollers, or may be provided with rollers or wheels, or may rest on trolleys having rollers or wheels, or may be partly or wholly supported by the wires. The filled mould may be slid only far enough to enable a second mould to be brought into filling position, this second mould being coupled to the first, and so on, each succeeding mould being coupled to the preceding mould and the whole train being pulled along the wires step-by-step to the setting station. There may be several parallel production lines, and the lines may be on more than one level, e.g. in two tiers. The moulds may be arranged in pairs, side by side. The apparatus used may be the same as that described in Specification 572,385. If a hold-up occurs, the wires are cleaned by the attrition device described in Specification 572,396. Specifications 338,864, [Class 87 (ii)], 364,621, 393,576 and 572,388 also are referred to.