1. Automatic welding machine for thermal joining of material sheets, in particular for edge-side joining of an overlapping upper material sheet to a lower material sheet, to be connected to one another in a materially bonded manner under the application of heat and subsequent application of pressure, comprising - a heating device for at least partially heating the material sheets to be joined in a connection region, - a support frame with a housing, - a pressure roller, - at least two travelling rollers (23, 24), wherein the pressure roller and the traveling rollers (23, 24) are arranged on the support frame and together with the support frame form a chassis, wherein the chassis comprises a longitudinal axis and a transverse axis perpendicular thereto, which span a chassis plane, wherein at least a first travelling roller of the two travelling rollers (23, 24) is arranged to be movable by a telescopic pull-out relative to the support frame in directions parallel to the transverse axis, wherein the first travelling roller and the heating device are with respect to a longitudinal center of the chassis arranged on opposite sides of the chassis; wherein the telescopic pull-out comprises an axle, wherein the first traveling roller is fixedly attached to the axle of the telescopic pull-out, wherein in an extended state the axle is pulled-out of the housing of the support frame and in a retracted state is received by the housing of the support frame; and wherein the elements of the telescopic pull-out are pushed into one another. - a heating device for at least partially heating the material sheets to be joined in a connection region, - a support frame with a housing, - a pressure roller, - at least two travelling rollers (23, 24), wherein the pressure roller and the traveling rollers (23, 24) are arranged on the support frame and together with the support frame form a chassis, wherein the chassis comprises a longitudinal axis and a transverse axis perpendicular thereto, which span a chassis plane, wherein at least a first travelling roller of the two travelling rollers (23, 24) is arranged to be movable by a telescopic pull-out relative to the support frame in directions parallel to the transverse axis, wherein the first travelling roller and the heating device are with respect to a longitudinal center of the chassis arranged on opposite sides of the chassis; wherein the telescopic pull-out comprises an axle, wherein the first traveling roller is fixedly attached to the axle of the telescopic pull-out, wherein in an extended state the axle is pulled-out of the housing of the support frame and in a retracted state is received by the housing of the support frame; and wherein the elements of the telescopic pull-out are pushed into one another. wherein the pressure roller and the traveling rollers (23, 24) are arranged on the support frame and together with the support frame form a chassis, wherein the chassis comprises a longitudinal axis and a transverse axis perpendicular thereto, which span a chassis plane, wherein at least a first travelling roller of the two travelling rollers (23, 24) is arranged to be movable by a telescopic pull-out relative to the support frame in directions parallel to the transverse axis, wherein the first travelling roller and the heating device are with respect to a longitudinal center of the chassis arranged on opposite sides of the chassis; wherein the telescopic pull-out comprises an axle, wherein the first traveling roller is fixedly attached to the axle of the telescopic pull-out, wherein in an extended state the axle is pulled-out of the housing of the support frame and in a retracted state is received by the housing of the support frame; and wherein the elements of the telescopic pull-out are pushed into one another.