Welding systems for motor vehicles bodies

Claim 1

System for welding motor vehicle bodies constituted by pressed sheet metal elements, adapted to operate automatically on at least two different types of body, comprising: a welding station; a conveyor line for conveying through the welding station a loosely preassembled motor vehicle body; means for accurately positioning the underbody part of said loosely preassembled body precisely at said welding station, a plurality of pairs of side gates on the two sides of the conveyor line; a series of positioning tools carried by each pair of side gates for accurately positioning the various parts of the body relative to said underbody part, the positioning tools carried by each pair of side gates being adapted to the configuration of a corresponding type of body; longitudinal guide means provided at the two sides of the conveyor line, said side gates being movable parallel to the conveyor line on said longitudinal guide means into or away from an operative position to allow the rapid replacement of the pair of side gates located in said operative position at the welding station, in dependence on the type of body to be welded, each pair of side gates being also movable between a spaced apart condition for the introduction of the body to be welded to the welding station, and a relatively close condition in which the positioning tools engage the body and locate the various parts thereof in the welding configuration; means for welding the body; and a store of auxiliary pairs of side gates having positioning tools corresponding to further different types of body, wherein the longitudinal guide means have separate end guide portions, wherein movable support means are provided for carrying said end guide portions, wherein the movable support means include gate-like support structures, each gate-like support structure being rotatable about a vertical axis between a first position in which the respective end guide portion is parallel to the conveyor line, so that it can receive a side gate when the latter is brought away from its operative position and a series of further positions for the transfer of the side gate to and from the store by the gate-like support structure, wherein the store of auxiliary pair of side gates includes a series of fixed structures located adjacent to each gate-like support structure, for supporting the auxiliary side gates in substantially radial planes relative to the axis of articulation of the respective gate-like structure, each of said fixed structures having a guide member which is aligned with the guide portion of the respective gate-like support structure when the latter is located in the corresponding transfer postion, and wherein each gate-like support structure is provided with means for rotating it about its articulation axis.