A device for dragging a killed animal when hunting. The method is carried out by means of a weaving machine which in the presence of an irregularity on a weft thread to be woven can be controlled in such a manner that at least one weft thread section which comprises the irregularity can be removed from the cloth being formed after an insertion operation. The self-centering feature may use a flow of blow-by gas in a clearance gap to provide a self-centering force on the piston assembly. The side members have a side rail engaging carriage at a lower end thereof for displaceable support engagement with a side rail secured to opposed sides of the platform. Interpolation may be performed between the moved or altered elements and between the elements and the remainder of the registration image to obtain a more satisfactorily registered image.