| 摘要 |
Apparatus is disclosed which serves to move a carriage in one direction over a predetermined distance at a substantially uniform velocity and for returning the carriage at a varying velocity so that a film web which is delivered at a constant velocity is intermittently advanced relative to a welding device, which fixed to a frame. The apparatus comprises a lever, which is adapted to be pivotally oscillated by a drive and which by means of a first guide provided on said lever and extending along said lever and a slider or roller cooperating with said guide imparts a motion to said carriage, which is movable in tracks in a plane which is parallel to the plane in which the lever is pivotally movable. The slider or the bearing for the roller is mounted on a holder, which is guided for a displacement along a line, which constitutes the base of an isosceles triangle, the sides of which are defined by the lever at the end positions of its pivotal movement. In order to provide such an apparatus which is more compact and spacesaving, the means for driving the lever comprise a crank, which revolves in a plane that is parallel to the plane in which the lever is pivotally movable, and said crank is carried by a driven crankshaft and carries a crankpin, which carries a slider or a roller, which is movable in a second guide provided on the , which second guide is disposed on that side of the lever which is opposite to the first guide . |
