The invention relates to a controller for a device for folding an envelope-window fold for use on buckle-folding machines, it also being possible to use the said device as a special accessory. The invention is based on the object of creating a controller for a window-envelope folding device, which controls the time movement sequence of the various sheet guiding devices in accordance with the values entered from a central point, as a function of the position of the sheet which is respectively to be folded, such that high quality of the window-envelope fold is achieved. According to the invention, at a defined point inside the pocket-folding mechanism, a clearly defined point on the sheet which is to be folded is detected by a sensor, which is fitted in a stationary manner, and the distance to be travelled by the sheet is measured from this point. In the case of a signal sequence which is preferably selected to be "light-dark" a counting process is triggered by the sensor, via one pulse. A further pulse transmitter likewise supplies pulses which are dependent on the machine speed to an electronic evaluation unit which consists of a plurality of modules and operates the actuating elements of the upper and lower sheet guiding elements.
展开▼
