A device for processing flat objects (40) delivered successively in a delivery direction, in particular print shop products, and/to a continuously advanced material web (42). The device, which is to be used particularly for welding a material web, includes at least one rigid body (90) that can be pivoted about an axis of rotation (D) and at least one tool (10) having a processing-effective zone (12), the tool being attached to the body (90) and movable along an orbit (U) by rotating the body (90). The tool is attached to the body (90) pivotally or rotatably about a pivot axis (S). The pivot position of the tool can be adjusted as a function of the rotational position of the rigid body by means of a stationary control gate and a control element interacting with the control gate and connected to the tool.