Abstract: The present invention relates in particular to a mold (M) for aluminothermic welding of a metal rail (1), which comprises at least two substantially identical pieces or shells (4), configured to be temporarily assembled opposite one another and on either side of said rail (1) to enclose the head (10), web (11) and foot (12) of this rail (1), each piece or shell (4) having an upper opening (43), which opens onto an internal cavity (44) bounded by walls (45, 46, 48) configured to enclose the head (10), the web (11) and the foot (12) of said rail (1), characterized by the fact that said internal cavity (44) comprises a compressible sealing coating (5) only against the walls (451, 46, 48) configured to enclose said web (11), foot (12) and underside of the head (10), with the exception of the rest of the head (10) and the underside of the foot (12).

Abstract: The invention relates to base part of a mold for aluminothermic welding of metal rails, which base part generally has a rectangular parallelepiped and has an upper face for receiving the foot of said rails, this upper face having a hollow cavity comprising a base, two opposing longitudinal side walls, and two opposing transverse side walls. The invention is characterized in that each of said longitudinal side walls has an intermediate region surrounded by two end regions, and these end regions are located in the same plane, whereas the intermediate region has a curved profile, the well of which is directed towards the opposite side wall.

Abstract: The present invention relates in particular to a mold (M) for aluminothermic welding of a metal rail (1), which comprises at least two substantially identical pieces or shells (4), configured to be temporarily assembled opposite one another and on either side of said rail (1) to enclose the head (10), web (11) and foot (12) of this rail (1), each piece or shell (4) having an upper opening (43), which opens onto an internal cavity (44) bounded by walls (45, 46, 48) configured to enclose the head (10), the web (11) and the foot (12) of said rail (1), characterized by the fact that said internal cavity (44) comprises a compressible sealing coating (5) only against the walls (451, 46, 48) configured to enclose said web (11), foot (12) and underside of the head (10), with the exception of the rest of the head (10) and the underside of the foot (12).

Abstract: The invention relates to base part of a mold for aluminothermic welding of metal rails, which base part generally has a rectangular parallelepiped and has an upper face for receiving the foot of said rails, this upper face having a hollow cavity comprising a base, two opposing longitudinal side walls, and two opposing transverse side walls. The invention is characterized in that each of said longitudinal side walls has an intermediate region surrounded by two end regions, and these end regions are located in the same plane, whereas the intermediate region has a curved profile, the well of which is directed towards the opposite side wall.

Abstract: A reflector is constituted by a right pseudo-dihedral, a ridge (C) of which is in the form of a portion of a helix so as to provide a calibrator or a beacon.

Abstract: A microwave phase shifter comprise a dielectric waveguide having a flat side and a moving conductor plane member substantially parallel to the waveguide side. Piezoelectric means are provided to move the plane member with respect to the waveguide side between a portion relatively remote from the waveguide side and an other position substantially in contact with the waveguide side. The piezoelectric means consists preferably of a stack of piezoelectric members supplied by a variable d.c. power source. Owing to the piezoelectric means for moving the conductor plane member, a variable phase shift is continuously adjusted. Such a phase shifter can be as an antenna network when the dielectric waveguide contains groups of radiator perturbations, such as conductor strips, respectively controlled by one or several piezoelectric means carrying conductor plates facing waveguide portions including the perturbations groups.