Abstract: The object of the present invention is used to clamp the fabric to be embroidered in mechanical and manual embroidery.In embroidery hoops with an outer contour deviating from the circular shape, the task is to achieve uniform distribution of the contact pressures over the entire clamped surface between the inner hoop and the outer hoop. This task is accomplished by designing the shape of the cross section of the sections of the inner hoop between two axes such that the bending stiffness is essentially constant over the entire circumference of the inner hoop and the extension stiffness decreases continuously between two axes such that it reaches a minimum in the area of the smallest radius of curvature. The cross-sectional shape of the sections of the outer hoop between two axes is designed such that the extension stiffness between two axes changes in the direction opposite the change occurring in the inner frame.

Abstract: A welding machine for foil webs which are overlapped comprises an undercarriage which includes a rectangular frame having longitudinal frame members and laterally adjustable transverse frame members with wheels supporting the frame. A welding device is positioned on the frame and it in the frame includes centering elements which may be adjustable so as to position the welding device accurately in respect to the frame. The welding device itself advantageously includes slots extending inwardly from each side into which a respective foil end is positioned and roller means which engage with one of the foils for guiding it as the undercarriage is moved over the top of the respective foils to be welded together. The undercarriage during the welding device includes a drive from the wheels to the rollers which includes a shaft assembly having a plurality of universal joints.