Abstract: A multi-point laser welding installation for vehicle bodies includes apparatus for positioning the pieces to be welded, apparatus for gripping the pieces and apparatus for welding the positioned and gripped pieces at specific points. The apparatus for positioning and gripping are provided with bearing surfaces. The shape of these surfaces conforms to the shape of the pieces. The apparatus for positioning and gripping include cavity which open the pieces at right angles. The welding apparatus is fixed on the positioning and/or gripping apparatus in order to ensure spot welding of the pieces at right angles to the cavities.

Abstract: An installation for determining the spatial coordinates of a point (P) on a piece (7) in particular for controlling a plant such as a welding plant for car bodies of motor vehicles. The installation is characterized in that it comprises a head (11) movable in a plane (X-Y) and produces a signal as a function of the distance of the point (P) in relation to the plane (X-Y), a rotor (13) on the head (11), this rotor comprising means for projecting a rotating laser beam (21.sub.4), at least three fixed targets (Q, R, S) arranged in the plane (X-Y) and the coordinates of which in this plane are known, these targets being capable of producing a signal as a function of the position (X.sub.P -Y.sub.P) of the head (11) and hence of the point to be measured (P) in the plane (X-Y). The invention is applicable to an installation for determining the spatial coordinates of a point.

Abstract: Method of and installation for spot-welding by laser beam, the method characterized in that the focusing means (3) undergoes displacement so that the point of focus (4) of the beam on the workpieces (4, 5) describes at least a path which is closed upon itself and of which the surface area of fusion obtained corresponds to the desired spot weld.The invention is applied to the welding of superposed workpieces.

Abstract: A method of spot-welding by laser beam, comprising a laser beam generator (10) and at least one means receiving the laser beam and focusing it on the pieces to be welded.

Abstract: This invention concerns a machine for working metals using an electron beam, characterized in that the gun and the enclosures occupy a fixed position in relation to one another, the gun being connected to each of the enclosures through a duct provided with a sealing valve a stage for electromagnetic deflection of the beam being provided between the gun and the ducts so as to deflect the beam successively towards the enclosures through the ducts.