Load-measuring devices

Claim 1

In a device for unloading the force from a pressure chamber having a diaphragm member connected with a movable forceunloading means and presenting an inlet for pressurized fluid at least on one side of the diaphragm member, the improvement comprising: an annular abutment surface provided adjacent the circumference of the inside of the chamber with which the edge portion of the diaphragm member engages when placed under load, which surface has the form of the intersection between a hollow body having the shape of said chamber''s circumference and a cylindrical surface having an axis which is perpendicular to that of the hollow body, wherein the abutment surface has two opposing elevations and two opposing depressions therein, and the abutment surface extends in the form of an arch from the elevations to the depressions and wherein the diaphragm member comprises a sealing diaphragm made of rubber or other flexible material, and a second diaphragm supporting said sealing diaphragm and being made of metal, such as spring steel, said rubber diaphragm at the positions most liable to deform under load, said positions being opposite the depressions on the abutment surface, is provided with axially outwardly bulging portions of such form that when the diaphragm is deformed under pressure the material of the diaphragm is not required to extend to any appreciable extent.