Milling unit with adjustable copying device

Milling unit with adjustable copying device (15)， comprising: - a milling cutter (11) which has a cutting edge (12) which is arranged in a ring shape with respect to a working axis (A) and which can be rotated about the latter in order to mill the edge (13) of a plate (14); - A copying device (15) which is connected to the milling cutter (11) and which is designed to rest on a surface of the plate (14) in order to guide the milling cutter (11) relative to the plate (14); wherein the copying device (15) comprises an annular element (16) which is coaxial to the milling cutter (11) and radially deformable， and an expansion device which is coupled to the annular element (16) to be on an inner surface (16a) of the the latter exert an adjustable force which serves to radially expand the annular element (16); characterized in that the expansion device includes: - At least one expansion element (18) which is coaxial to the milling cutter (11) and has an outer edge (18a) which is designed to engage with the inner surface (16a) of the annular element (16)， the Expansion element (18) is reversibly deformable between a first configuration in which at least a section of the outer edge (18a) is at a first distance from the working axis (A) and a second configuration， in which this section has a second distance from the working axis (A) which is greater than the first distance; - An actuating element (19) which is movable along an actuating direction (B) parallel to the working axis (A); wherein the expansion element (18) and the actuating element (19) are connected to one another and are designed such that movement of the actuating element (19) along the actuating direction (B) results in deformation of the expansion element (18) between the two configurations， whereby this Deformation includes a variation in the expansion of the expansion member (18) along the working axis (A).