Panel connection device

A clamping device (136) for attaching a bar (130) of an inner grid (46) to an external frame (12, 14, 16 and 18) for a lower blanking tool of a machine punching of cardboard boxes, comprising: a plate member defining an internal face extending vertically (140), an opposite outer face which extends vertically (142), an upper face extending horizontally (144) with a cavity (156) formed in therein for receiving a portion of the bar (130) and a hole (194) extending between the inner face (140) and the outer face (142) along an axis at an acute angle to the outer face (142), the cavity (156) in the top face (144) of the plate is defined by first and second spaced sidewalls extending vertically (158, 160) extending between the outer and inner faces (140, 142) and a lower horizontal wall (162); and a wedge element (166) rotatably disposed in the cavity (156) and which is movable between a holding position for maintaining the part of the bar (130) in the cavity (156) of the plate and a position release, the wedge element (166) including a clamping surface (168) engageable to the rod (130) with the wedge (166) in the clamping position.