Abstract: Method of laser welding sheet metal protected by using low-vaporizing-temperature materials, whereby, before being subjected to a laser welding beam along a weld area, two metal sheets are placed on top of each other in such a manner that at least one layer of the said protecting material is located between the sheets at the weld area and that the weld area communicates directly externally of the weld area between the sheets whereby gases generated by vaporization of said protective material may escape from the weld area.

Abstract: A machine (1) (53) (75) for effecting the transfer of objects in the space between positions having predetermined co-ordinates, in which said objects are supported by a head (25) integral with a pinion (20) (60) mounted rotatable on a slide (12a) (59) sliding in a direction perpendicular to the axis of said pinion (20) (60); the pinion (20) (60) meshing by opposing means with teeth (21) (64, 65) (76, 77) extending along said slide (12a) (59) and axially moving under the bias of driving apparatus (41, 42) (68, 69).

Abstract: An automatic bolt tightening device for assembling mechanical members placed on a buck arranged above the bolt tightening device. The bolt tightening device is provided with a headstock which is translatable along three mutually perpendicular axes. A rotatable spindle, arranged on the headstock, cooperates with the terminal part of a tang, which in turn cooperates with bolts for assembling the members. The translation of the headstock and the rotation of the spindle are actuated by motors which are controlled by a processing unit. A plurality of sensors detect the positions of the buck relative to the bolt tightening device and of the spindle relative to the tang, and output error signals to the processing unit. The processing unit controls the operation of the motors, thereby translating the headstock until the spindle and tang are coaxial.