Damper for a weighing device and a weighing device provided with a damper

A weighing device including a frame, a sensor provided as a deformable monolithic rod (2), of which one end (2b) is affixed to the frame (1) while the other end (2a) receiving the load (P) to be weighed is fastened to the plate (12) of a hydraulic damper movable within a cavity (4), characterised in that this cavity (4) is provided in the frame (1) and in that it is tightly closed by a flexible membrane (14);

• that this cavity (4) is partly filled with an oil leaving a volume of air or of a gas between the top (14a) of the oil and the membrane (14), the plate (12) being totally immersed in the oil;
• in that the lower surface (12b, 12c) of the plate (12) and the bottom (5, 6, 7) of the cavity (4) have shapes which are not planar and which are not parallel to each other, thus preventing the formation of a thin film of oil between them;
• in that the peripheral surface of the plate (12) and of the peripheral wall of the cavity (4) define therebetween a first constriction (15) of which the transverse section is constant whatever the position of the plate (12) in the cavity (4);
• and in that the peripheral area (5) of the bottom of the cavity (4) and the peripheral area (12b) of the lower surface of the plate (12) facing the bottom of the cavity (4) define together a second constriction (16) of which the transverse section varies depending on the position of the plate (12) inside the cavity (4).