A rod whose shell support of the gum is fixed by welding ultra - sounds and shell adapted

摘要

In the rod (1) to a central lead (2), provided at its rear end of a rubber (6) mounted in a sleeve (5) fixed on the body of said rod, the peripheral body (7), surrounding the mine (2), and the shell (5) are made of compatible thermoplastic materials, the bottom of the sleeve (5) is fixed on the rear end of the pencil by localized interpenetration of said thermoplastic materials, in at least one ultrasonic welding zone. & br / preferably, the material of the peripheral body (7) of the rod (1) is expanded, having a density of the order of 0,5 to 0,6, and the rear end of said body (7) has a neck having locally increase the density. & br / the sleeve (5) comprises, on the outer face of the base a shoulder, in particular, of annular shape forming an energy director for the weld ultra -.