Abstract: A mechanical expansion device for internally clamping assembled hollow sections includes at least two angle pieces (10) and (10') which fit inside a section (1), and at least two spherical cups (8) and (9) spaced on a rod (7) and placed between the two angle pieces. One cup (8) bears on the inner face of the angle pieces and the other cup (9), of a slightly larger diameter, bears on the inner face of the section (1) at the end of the angle pieces. Clamping is effected by flattening the cups to increase their diameters.

Abstract: A protective encasement for machine tools comprises a fixed part and a movable part composed of profiles assembled to form uprights and cross-pieces, bearing components controlling safety circuits activated by action of the movable part. The fixed part is composed of a single profile with a closed central cell, surrounded by several open cells which can receive windows and fixing and activating means and can be closed, and which contain the safety components and circuits. The movable part comprises a L-shaped profile connected to the fixed part and protecting contacts which cooperate with the components of the fixed part.

Abstract: A clip of round spring steel wire or rod stock for jam or wedge fastening two extruded members together, one of which has a square cornered U-shaped cross-section with an inturned edge on one of its arms, comprises four distinct, straight, continuous branches. Three of the branches 1, 2, 3 lie in a common "bending" plane, and the third and fourth branches 3, 4 define a dihedral plane which forms an acute, perpendicular or obtuse angle with the bending plane--depending upon the desired direction of relative longitudinal movement between the two extrusion members. The unstressed angle between the third and fourth branches is initially 45.degree., which is bent to less than 45.degree. during the installation insertion of the clip in the U-shaped member, wherein the bending plane forms an internal diagonal across the member from the corner of the inturned arm.

Abstract: A multi-piece complex metal framework is disclosed wherein first and second pieces are retained in clamping relationship by the force exerted by a third, resilient strip inserted between the first and second pieces. The framework may be used to clamp and retain a sheet-like article, and to fabricate structural beams having means to retain sheet-like article.