Pillar Formwork

Abstract

A column formwork for use in concrete construction is described, including a planar member 1 constituting the formwork, and at least one connecting section provided for form-fit connecting two opposing edges 3, 3′ of the planar member (1) and thus for constituting a tube segment, wherein at least the connecting-section surface facing the planar member 1 exhibits a substantially constant curvature that substantially corresponds to the curvature of the tube segment.

Description

[0001]This application is a continuation of U.S. application Ser. No. 10 / 497,592, filed Jun. 3, 2004.FIELD OF THE INVENTION[0002]The present invention is directed to a column formwork for use in concrete construction.BACKGROUND OF THE INVENTION[0003]Column formworks are used in concrete construction to build columns, supports, or similar concrete elements. Recently, in addition to conventional steel and wood formworks, wound formworks of sheet metal, cardboard, or synthetic material have increasingly been employed. In the case of wound cardboard formworks, the outer formwork tube, which primarily serves to hold the formwork together, is constructed of paperboard or cardboard. After the column has been concreted and the concrete has set, the outer formwork element is removed by tearing it open by means of an integrated tear strip.[0004]A column formwork comprising a multilayered wound flat material is known from DE 295 18 077. The flat material is a polyethylene-coated paper sheet. D...

AI Technical Summary

Benefits of technology

[0011]The column formwork according to the present invention can be transported with no difficulty in large quantities in a flat state before bending it into a tube.

[0013]According to a preferred embodiment of the present invention, the planar member comprises an elastic synthetic material. Such a material fulfills the two above-mentioned conditions especially well, namely sufficient shape-retentiveness after the concrete is poured and, at the same time, sufficient elasticity that allows bending into a tube with no difficulty. Such a column formwork exhibits the great advantage that no single-use materials are provided, such as the typically used cardboard, thus facilitating multiple reusage of the formwork.

[0015]However, an embodiment having just one connecting section attached near an edge of the planar member and protruding over this edge is also conceivable. The part of the connecting section protruding out over the edge is then connected with the planar member near the opposing edge after the planar member is bent into a tube segment. This connection can, in principle, take place in any manner, for example through glueing. However, the planar member can also exhibit e.g. projections that engage in corresponding recesses of the connecting section and thus facilitate a secure form-fit connection of the opposing edges.

[0023]Most particularly advantageous characteristics result when the connecting sections and the planar member comprise the same material. In this way, an especially simple and tight connection between the parts is possible through glueing.

[0024]To ensure a secure, form-fit connection of the opposing edges of the planar member, in the context of the present invention, it is particularly preferred that the connecting sections extend in the direction of the tube segment axis over the entire length of the tube segment. In this way, the edges of the planar member can be form-fit connected over the entire length of the column formwork with particularly great strength and precision.

[0026]Another important condition for achieving good results in the form of an excellent surface finish of the concrete columns is preventing water and cement paste from penetrating the formwork. At the junction of the edges of the planar member, there is a risk that, in the case of an insufficiently form-fit junction, water penetration and thus bleeding of fine concrete components could occur at the seam. This can cause visible unevenness on the surface of the concrete column. For this reason, a planar member and connecting sections are preferably used whose edges are especially smooth due to an appropriate subsequent treatment such as grinding or polishing, and that facilitate a very good, precisely fitting connection. Furthermore, according to a particularly preferred embodiment of the present invention, the tongues of the connecting sections are equipped with seals, thus preventing penetration of water through the connecting sections.

Problems solved by technology

If connecting sections having no curvature are used, the bent planar member would take on a slightly tear-shaped form and thus cause unsatisfactory results in the concrete parts.

Images