Abstract: A method and device for hemming metal sheet involving upsetting the sheet metal to form a skirt at an angle to the parent sheet and for hemming the skirt to the parent sheet or another sheet interposed therebetween. Both skirt forming and hemming utilize rotary bending tools to convert perpendicular motion into rotational bending force. The novel device of the present invention is a rotary hemming tool having a cylindrical rocker characterized by a flat extending along its length with two lobes defining the intersection between the flat and the cylindrical surface of the rocker. The flat and the lobes are the surfaces of the rocker which act against the upset metal skirt and against the anvil on which the metal sheet is placed. The rocker and saddle are configured to limit rocker rotation such that skirt bending commences simultaneously with rocker contact rather than interaction between the rocker and the anvil.

Abstract: A rotary bending tool, consisting of a rotary bending head, a saddle block with bearing surfaces and retaining key for holding the rotary bending head, a restoring member for the rotary bending head and a bottom die, the bearing assembly of the rotary bending head being equipped with a continuous lubricating device. The continuous lubricating device consists preferably of lubricant chambers, which are fed via a lubricant-delivery duct. Preferably the restoring member for the rotary bending head is integrated in the lubricant-delivery duct.

Abstract: A bending and forming device is disclosed having an operating head and its holder features a holder which is a multi part structure including a saddle for seating the head and a releasably connected gib, a limited portion of which is adapted to releasably bear on and hold the head to and for a rocking or rotative movement thereof on its seat. The head is preferably a cylindrical body having a groove the length of its outer peripheral surface, the bounding walls of which groove determine the operation to which the head may be applied. The retention device is connected to the saddle so as to enable an easy adjustment of its position to accommodate variation in the dimension of the operating head or wear of the related parts. In preferred embodiments the saddle affords a concentrated load bearing surface for the head provided by relatively narrow, adjacent and relatively spaced, longitudinally extended, strip-like bearings.