Device for bending pipes

Description

[0001] The invention relates to a device for bending pipes with a bending spiral spring that can be placed in a pipe in the area of ​​a bend to be formed, wherein a core is inserted into the bending spiral spring.

[0002] US 230125 A discloses a device for bending thin-walled pipes. The bending mandrel is constructed in particular in several parts and consists of a steel spring casing surrounding a rubber core or core. The steel spring casing is either slightly conical or cylindrical. US 2760545 A discloses a device for bending thin-walled pipes, wherein a core made of an inner spiral spring is inserted into an outer spiral spring. A spiral spring can be placed in a pipe in the area of ​​the bend to be formed using tension means or a push wire (AT 14 096 U1).

[0003] US1675574A, on which the preamble of claim 1 is based, discloses a device in which a tension cable is inserted into the flexible spiral spring. The tension cable consists of fibers running in the longitudinal direction of the tension cable.

[0004] Pipes are usually manufactured by the meter and must be cut to length on site at a construction site and bent manually into the desired shape. Nowadays, composite pipes are usually used for plumbing and heating installations. These pipes have an outer layer made of plastic, a middle layer made of aluminum, and an inner layer made of plastic. Plastic-coated, thin-layer stainless steel pipes are also now being used. To prevent pipes, regardless of their design, from kinking during bending, it is well known that bending springs are used to prevent the pipe from kinking in the area of ​​the bend. Pipes bend particularly when the bending radii are too small, less than 5 times the pipe diameter. To do this, the bending spring must be pushed inside the pipe into the area of ​​the bend to be created before the bending process.

[0005] Such bending springs are typically around one meter long and made of spring steel. They are constructed like a helical spring, with the individual coils typically tightly packed together, and the helical spring wire may have a rectangular cross-section to ensure the largest possible contact area inside the tube between the inner layer and the bending spring, thus protecting the inner surface of the tube as much as possible during bending. After the tube has been bent, the spring is pulled out of the tube. Tension devices such as ropes, a rigid metal wire, or a push wire known from AT 14 096 U1 can be used to retract or extend the spring.A particular disadvantage of the known devices is that the bending radii cannot necessarily be precisely defined and that if handled improperly, particularly if excessive bending power is applied, i.e. bending forces are applied in a short bending time, the pipes will still buckle in the area of ​​the bending point.

[0006] Based on such prior art, the invention seeks to provide a device for bending pipes that can increase resistance to buckling and limit bending radii, particularly when bending pipes manually. The invention achieves this objective by providing a core made of fibers running in the longitudinal direction of the core and designed to prevent radial deflection of the spiral spring during bending, thus preventing buckling.

[0007] The interaction between the spiral spring and the core increases resistance to buckling and limits bending radii. The core prevents radial deflection of the spiral spring during bending, thus preventing buckling. Furthermore, the device remains easy to place in the pipe being bent and can be easily removed even after bending. The desired bending radius limitation can be adjusted using the flexural rigidity of the core.

[0008] The core consists of fibers running longitudinally along the core, particularly glass, carbon, basalt, or metal fibers. The fibers form a compact, highly radially resilient package and, with appropriate selection of fiber parameters such as tensile strength and diameter, allow for improved adjustability of the bending radius limitation. For simplicity, the core can be or be a rope, particularly a metallic one.

[0009] To increase the core's stability, it is advantageous if the core has a plastic coating on its outer circumference, particularly made of abrasion-resistant plastic. This also reduces friction between the core and the flexible spiral spring, which facilitates removal after the bending process, since the spring can still be axially stretched within limits on the core if dimensioned accordingly.

[0010] Likewise, the core can be a plastic rod and / or made of fiber-reinforced plastic, i.e. a core consisting of fibers running in the longitudinal direction of the core can be embedded in plastic, synthetic resin or the like.

[0011] According to a further development of the invention, the core can be extended to form a push wire, which allows the flexible coil spring to be positioned in the area of ​​the bend to be formed. This eliminates the need for a separate connection between the flexible coil spring and the core. Furthermore, a kink-proof connection between the push wire and the flexible coil spring is provided.

[0012] Likewise, the core or push wire can be made of filler-reinforced plastic, especially plastic reinforced with mineral fillers, which allows the elastic modulus and stiffness of the push wire to be adjusted. Furthermore, the push wire, like the core, can have a fiber core. This ensures that the shear and tensile forces required for proper handling can be safely absorbed and easily transferred to the flexible spiral spring. Damage to the inner pipe casing due to improper attachment of the push wire to the flexible spiral spring can thus be avoided from the outset.

[0013] The drawing shows an example of the subject matter of the invention. Fig. 1 shows a partially sectioned longitudinal section of a spiral spring with core placed in a tube in the area of ​​a bend to be formed and Fig. 2 shows a design variant of the device from Fig. 1 with a core extended to a push wire.

[0014] The device for bending pipes 1 comprises a bending spiral spring 2 which can be placed in a pipe 1 in the region of a bend B to be formed, wherein a core 3 is inserted into the bending spiral spring 2.

[0015] To bend a pipe, the bending coil spring 2 is first placed in the area of ​​the bend B to be formed in an initially straight pipe 1. The pipe is then manually bent to the desired angle. Finally, the bending coil spring 2 is removed from the pipe 1.

[0016] The core 3 has a plastic sheath 4 around its outer circumference, particularly made of abrasion-resistant plastic. The flexible spiral spring 2 rests against or on the plastic sheath 4 of the core 3.

[0017] The core consists of fibers running in the longitudinal direction 5 of the core, optionally a rope, in particular glass, carbon, basalt or metal fibers, which are optionally embedded in a plastic or synthetic resin matrix or the like.

[0018] According to the design variant according to Fig. 2 the core 3, at least a core of the core 3, is extended to a push wire 6, with which the bending spiral spring 2 can be placed in the area of ​​the bend to be formed.

Claims

1. A device for bending tubes (1), comprising a spiral bending spring (2) placeable in a tube (1) in the region of a bend to be formed, whereby a core (3) is inserted into the spiral bending spring (2), characterized in that the core (3) consists of fibres oriented in the longitudinal direction (5) of the core and is configured in such a way that it prevents the spiral bending spring (2) from moving radially during bending and thus from buckling.

2. A device according to claim 1, characterized in that the core (3) has a plastic sheathing (4), in particular made of abrasion-resistant plastic, on its outer circumference.

3. A device according to claim 1 or 2, characterized in that the core (3) consists of glass, carbon, basalt or metal fibres.

4. A device according to one of claims 1 to 3, characterized in that the core (3) comprises a, in particular metallic, cable.

5. A device according to one of claims 1 or 2, characterized in that the core (3) is a plastic rod and / or consists of fibre-reinforced plastic.

6. A device according to one of claims 1 to 5, characterized in that the core (3) is extended to form a push wire (6) with which the spiral bending spring (2) can be placed in the area of the bend to be formed.