Tool holder device for shearing machine

A tool holder device (10, 10′) for shearing machines, especially of the longitudinal type, suitable for processing on paper, cardboard, plastic films, various laminates, aluminium, fabric, non woven, fibreglass, carbon fibre and the like, comprising a blade holder head provided with a preferably circular blade (12), partially protected by a casing (14) and rotatably connected to an elastically deformable arm (16) and to a bar (18) sliding according to a vertical direction, a further protection element for the same blade defined by a shaped plate (20) provided with a through opening (22), at least one piston (30, 32) for the up/down movement of the blade holder, with said bar (18) and said at least one piston (30, 32) arranged and moved in a chamber (23) of a support body (24), a vernier scale (62) arranged at the top of a flanged adjustment bushing (54) and stabilised to the top front of the support body (24), provided with a graduated scale along an outer vertical portion of the cylindrical surface of said adjustment bushing, the tool holder device characterised in that it comprises a cover (26, 70) placed for closing the bottom portion of the support body (24), axially sliding relative to the same support body and formed by two portions (15, 15′, 71, 71′) not matching and suitable for partly circumscribing the bar (18) and torsionally tightening it by a screw (28, 72), said cover comprising a base or bottom (26′, 70′) from the top front whereof a collar (26″, 70″) develops according to a vertical direction, which externally circumscribes a bottom portion of the support body (24).