In-line moulding of prestressed concrete articles

A method of moulding concrete ties comprising the steps:

• aligning a series of similar multi-cavity open ended moulds end to end in a plurality of groups, and between end beams at the ends of a bay,
• positioning a series of reinforcing wires in parallel spaced relationship with one another in the aligned cavities of the moulds and between the end beams,
• securing the ends of the reinforcing wires to said end beams and straining said reinforcing wires,
• positioning a series of flat sided bar-like spacers between the ends of adjacent moulds of each group and between the reinforcing wires so that:
• a. the spacers function as closure members for the ends of the moulds, the opposite flat sides thereof becoming contiguous mould ends, and
• b. the upper and lower edges of the spacers engage the reinforcing wires to retain them in horizontal rows,
• each said flat-sided bar-like spacer extending across the width of the multi-cavity moulds and spaced vertically from adjacent said flat-sided bar-like spacers solely by the wires retained by said adjacent bars in a said horizontal row,
• positioning a plurality of flat spacer plates each between adjacent ends of said groups, each plate extending across the width of the multi-cavity moulds and having transversely spaced vertically extending slots extending downwardly from its upper edge, and elevating the flat plates to engage the wires in the slots and also to cause its opposite side faces to function as closure means for contiguous mould ends, the edges defining the slots retaining the wires in vertical rows,
• driving the moulds towards one another by an amount sufficient to close any gaps which exist between the mould ends and said spacers and said spacer plates,
• discharging a wet mix of concrete into the moulds to surround the reinforcing wires and allowing the concrete to set,
• withdrawing the flat-sided bar-like spacers endwise from between the horizontal rows of wires in a lateral direction and depressing flat spacer plates from between the rows of wires in a vertically downwards direction against resistance to concrete fracture by the mould bases to thereby expose the wires between adjacent ends of aligned moulds, and between the groups, and
• severing the wires between each pair of adjacent moulds.