Formwork core for a formwork system for casting a bell-shaped body

A formwork core for a formwork system for casting a bell-shaped body, comprising:

• vertical corner supports;
• wherein:
• the vertical corner supports each carry two corner connection panels, which are arranged perpendicular to each other around a corner and are synchronously retractable and extendable without touching, wherein, in a fully extended state, a vertical gap remains between the two corner connection panels in an area of the corner;
• the vertical corner supports each carry a corner bracket, which are synchronously retractable and extendable and, in the fully extended state, close the vertical gap between the two corresponding corner connection panels to form a vertical outer edge of the formwork core;
• vertical edges of the corner connection panels remote from the corner can be releasably attached to one another, or to intermediate elements between the corner connection panels;
• the corner brackets are connected to the vertical corner supports by first hinged connectors;
• and
• the corner connection panels are connected to the vertical corner supports by second hinged connectors that are separate from the first hinged connectors, the first and second hinged connectors allowing upward movement of the corner brackets and the corner connection panels relative to the vertical corner supports.