from the swivel axis 20a spaced increasingly distant as the locking element turns counterclockwise so that movement of the clamping face 21a in the withdrawal direction 300 of the window pane 3 ensures increasing clamping force the necessary contact pressure of the clamping face 21a against the surface of the window pane 3 is produced by a spring element 4a which is supported on the arm 11a if the locking element 2a is an injection molded plastic part then the spring element 4a can be injection molded advantageously in the so called twin component technique a further spring element 5a possibly made of elastomer is mounted between the base 10a and the lower edge of the window pane 3 spring element 5a ensures a low degree of canting or tilting of the window pane where the locking element 2a would already be swivelled slightly counterclockwise is constantly maintained with regard to the marginal conditions which are concerned with friction and which are necessary for reliable functioning of the fixing device the same applies for the embodiments according to fig2 and 3 as for the embodiment already described in fig1 the angle u03b1 between the plane e1a or e1b holding the clamping line 210a 210b and the swivel axis 20a 20b respectively and the plane e2a e2b running orthogonal to the plane of the pane should in turn meet the equation the embodiment of fig3 combines the technical features of fig1 and 2 since the.