Abstract: A toggle-type clamping device which grippingly and compressingly engages a clamp bar in order to secure a de-watering or sizing screen within a vibrator is disclosed. The clamping device is mounted on the side of a vibrator support member that is opposite the clamp bar and includes an L-shaped clamping member which passes through an aperture in the support member permitting engagement of the clamp bar by the clamping member. The clamping member grippingly and compressingly engages the top surface of the clamp bar and the surface of the clamp bar that is opposite the support member causing the clamp bar to be compressed against the support member in the lateral direction and against the de-watering or sizing screen in the transverse direction preventing lateral and/or transverse movement thereof.