A stair is a type of prefabricated element that can be fully variable in all its dimensions.
Consequently, the mould used to manufacture it is something very particular that needs to be studied in all details together with the customer.
Stair Mould with fixed sizes
When a large number of elements with the same dimension of risers and goings needs to be prefabricated, it’s correct to make them in a fixed mould.
We consider stair poured in vertical position (in order to have the best surface finishing on both of upper and lower part of the element). The mould is made by
A base frame where the base plate is leaning.
2 lateral sides, one smooth, with the shape of the lower part of the stair, and another with bent plates that replicate the different steps.
At the 2 extremities of the sides, there are the landing equipments
Access stair and walkway platform is included in case mould is too high to be accessed from ground level.
Sides are fixed to the base frame and can be opened manually with an articulated lever.
Base plate can be raised up with telescopic supports, thus adjusting the stair width.
Number of steps and landings can be adjusted by simply moving the lateral separators.
Flexible Stair Mould
When stairs of several different dimension need to be manufactured it’s appropriate to use a flexible staircase mould.
On the base frame the base plate can be adjustable in height by means of a telescopic support or a hydraulic cylinder.
The smooth lateral side can be opened and closed hydraulically.
The side that replicate the steps shape has a fixed position but can change both risers and going dimensions. The adjustment of the step can be done manually or hydraulically with the pantograph.
The landings sides can be placed in different positions in order to produce stairs of different number of steps.
The step side can incorporate timber blocks to close the gaps between risers and tread.
The lateral sides can incorporate triangular magnetic chamfer in the connection with variable positions.
Any coupling between movable parts of the mould in contact with concrete is equipped with rubber gasket in order to avoid concrete leakages. The gasket that can be conceived either underneath the casting surfaces, with metal chamfer bolted on the casting plates, or welded on the shuttering, with special shape (GF type) that guarantees the presence of the chamfer in the rubber itself.
Stair Mould can be equipped with a vibration systemconsisting of a series of vibrators that can be electric or pneumatic. The vibration compacts the concrete by removing air and increases its mechanical strength after curing. Furthermore, vibration allows using concrete with less moisture and accelerates the curing process, in order to increase productivity. Click on this link in order to examine all the range of Bianchi product in vibration for prefabrication.
Accelerated curing with hot water or steam is not so frequently used in this type of moulds.