The invention relates to a method for producing a flat spiral spring, in particular a spring sheet for covering a cooling area of a piston of internal combustion engines, said spring sheet being formed at least as an annular disk-shaped segment (12), wherein a strip-shaped material (23) is fed to a bending device (27) that comprises at least one drum (29), said drum rotating about a rotational axis (31), and the strip-shaped material (23) is supplied in a tangential alignment to the lateral surface (36) of the drum (29) such that a lateral wall (20) which determines the thickness of the strip-shaped material (23) rests against at least some sections of a contact surface (37) on the lateral surface (36) of the drum (29). The contact surface (37) of the drum (29) has a radius which substantially corresponds to an internal radius of the strip-shaped material (23) to be bent into the segment (12), and at least one deflecting device (32) is aligned at a distance to the drum (29) such that the strip-shaped material (23) is guided in a forced manner between the drum (29) and the deflecting device (32), and the strip-shaped material (23) is bent so as to follow the drum (29) by means of the deflecting device.

The present invention is directed towards an automated bending device for bending a strip of material into a desired shape. The device is either a single or dual bending tool with interchangeable rotating bending dies which allows for a faster transition from a break bend to a radius bend using air cylinders for positioning of the tools.

A method for producing a flat spiral spring formed as an annular disk-shaped segment, wherein a strip-shaped material is supplied in a tangential alignment to the lateral surface of the drum such that a lateral wall which determines the thickness of the strip-shaped material rests against some sections of a contact surface on the lateral surface of the drum. The contact surface of the drum has a radius which substantially corresponds to an internal radius of the strip-shaped material, and at least one deflecting device is aligned at a distance to the drum such that the strip-shaped material is guided in a forced manner between the drum and the deflecting device, and the strip-shaped material is bent so as to follow the drum by means of the deflecting device.

A method of making a heat exchanger includes providing an inner tube extending longitudinally along a central axis and having an inner surface bounding a product chamber and an outer surface. An outer tube is formed and positioned about the inner tube. The outer tube is disposed coaxially about and circumscribing the inner tube in a radially spaced relationship. Forming the outer tube and positioning the outer tube about the inner tube occur simultaneously.

The present invention is directed towards an automated bending device for bending a strip of material into a desired shape. The device is either a single or dual bending tool with interchangeable rotating bending dies which allows for a faster transition from a break bend to a radius bend using air cylinders for positioning of the tools.