DE2722824A1 - Bent hollow aluminium profiled section prodn. - in which foamed polyurethane is extruded into hollow and allowed to set before bending - Google Patents

Abstract

Hollow, profiled sections are bent to an arcuate and their non-symmetrical bending is prevented by filling the hollow space with foamed polyurethane which is allowed to set before bending. Pref. the foamed polyurethane is extruded into the sections using moveable head and the foamed polyurethane is allowed to set. Difficult and inaccessible spaces are fully filled and collapsing of sections is prevented.

Description

Method for bending hollow profiles

The invention relates to a method for bending hollow profiles, in which the cavities are filled with almost incompressible media and then in bent to the desired shape.

In particular, it is known to use straight pipes with appropriate bending devices or to bend by hand, the pipes with almost incompressible media, such as Water, oil, wax or the like. Filled and then on a molded piece in the desired Shape to be bent.

When using flowable filler materials, the ends must the pipe sections to be bent are tightly closed, including special closure devices are necessary.

In the case of the fillers solidifying in the pipes, the difficulty arises to remove these fillers from the cavities again after the bending process. on Due to the relatively high weight and cost of the fillers, such hollow profiles that are not later used for recording or

serve to convey liquid or gaseous media, the fillers do not remain in the curved profiles.

Reusable cores for internal support are also known tubes to be bent, which also have undesirable deformations during the bending treatment avoid.

However, these cores can only be used for one profile cross-section. In addition, it is difficult to take out the cores after the bending treatment. the end These cores cannot follow either cost or weight reasons the bending treatment remain in the hollow profiles.

The object of the invention is to provide a method of the above to propose mentioned type, with the production costs of curved hollow profiles can be reduced.

Such a method is thereby used to achieve the object of the invention characterized in that a hardening foamed plastic is introduced into the cavities will.

The cavities of the corresponding profiles should preferably be used filled with polyurethane foam. This in a simple manner into the cavities foamed plastic to be introduced with appropriate nozzles or hollow mandrels hardens after a short time with complete filling of the cavities. While filling out it is not necessary to close the ends of the profile sections. Minor escaping foam can be removed later.

The hardening foamed plastic forms an almost incompressible one Medium in the hollow profile and supports with the appropriate selection of the adjustable hardness the profile is sufficiently removed from the inside during the bending treatment. The degree of hardness can depend on the type of profile, its wall thickness and the one to be bent Radii can be set.

The method according to the invention is of particular importance in bending of hollow profiles, their interiors with a later processing and use cannot be used.

The hardened plastic foam that only uses a small amount of material requires and has only an extremely low specific weight, can in the hollow profile remain.

Compared to all other known fillers, the foamed Plastic a considerable weight advantage.

In addition, when filling the flowable plastic foam special locking means for the ends of the profiles can be dispensed with.

This foaming according to the invention proves to be particularly advantageous for bending light metal profiles, for example made of aluminum, where the advantage of the low weight is only insignificant from the filled plastic foam being affected.

Using an aluminum profile section shown in perspective the method according to the invention is explained in more detail.

In the initially straight hollow profile 1 is more flowable, more hardening Plastic foam, for example polyurethane, introduced. This plastic foam can for example in the cavity 2 of a profile section with an injection nozzle are injected, which is pulled through the profile section with a mandrel will. The plastic foam, which automatically expands into all rooms, then hardens adjustable hardening time with an adjustable degree of hardness for the plastic foam core 3. When bending such a filled profile section on appropriate Bending devices, this core 3 supports the profile walls from the inside, so that deformations be avoided.

Any hard foam that has leaked out at the ends of the profile can can be easily removed, so that the entire profile section for further processing is usable.

The method according to the invention offers particular advantages in the case of hollow profiles with several and possibly difficult to fill cavities, as the plastic foam expands within the cavities and certainly leads to a filling, which is absolutely necessary for the later support during the bending process.

The method can also be used for double-shell hollow profiles where the shells are rigidly connected to one another before they are filled.

Claims (2)

Claims 1. A method for bending hollow profiles, in which The cavities are filled with almost incompressible media and then in the desired Shape are bent, characterized in that in the cavities (2) a hardening foamed plastic (3) is introduced. 2. The method according to claim 1, characterized in that the cavities (2) filled with polyurethane foam (3).