direction causes the upper shaft 1 to slide axially towards the left through a distance 2r relative to the lower shaft 2 thus enabling the blade 7 to be moved away from its associated counter blade 8 as shown schematically by the arrow 17 in fig1 the axis 1a of the upper shaft 1 and likewise of the central part of the upper spindle 3 is eccentric in relation to the axis 3a of the journals 3b 3b1 of the upper spindle 3 which journals respectively engage the bearings formed in the side plate 9a and the movable support 10 the eccentricity between the axes 1a and 3a is indicated by the letter e in fig1 when the upper spindle 3 is displaced towards the side plate 9a through a distance 2a by pivoting the handle 15a through an angle of 180 u00b0 in an counter clockwise direction about the shaft 16 causing the blade 7 to undergo a horizontal displacement in relation to the associated counter blade 8 the washer 30 expands and releases the upper spindle 3 which can then rotate freely about its axis 3a thus it is possible to separate the pair of blades 7 7a to inspect and service them without having to loosen the securing screw 13 and the blade 7 may be quickly re positioned adjacent blade 7a at the proper clearance this rotation effected by pivoting the handle 15 in.