Mount having hydraulic damping action and membrane therefor

In a mount for hydraulic damping action having a pedestal, a mounting bracket, a spring element connecting the pedestal and mounting bracket, means defining variable-volume working and equalizing spaces for filling with an hydraulic fluid, the means defining the working space being operatively connected to the pedestal for varying the volume of the working space in response to movement of the pedestal relative to the mounting bracket, and the means defining the working and equalizing spaces comprising an elastic membrane separating the working and equalizing spaces for bulging in response to a pressure differential of the hydraulic fluid therein, and at least one throttle opening for throttled flow of the hydraulic fluid between the working and equalizing spaces in response to a pressure differential therebetween, the improvement comprising:

• a peripheral, integral bead about the membrane, whereby the membrane has opposite surfaces extending inwardly from its bead, said bead having a thickness which is greater than the thickness of said membrane between said opposite surfaces next adjacent thereto;
• projections from the mounting bracket for holding the bead of the membrane between them, said projections being radially spaced from said bead when said membrane is not bulged, to permit said membrane to bulge outward without substantial stretching;
• and
• a nonrectilinear cut through the membrane between the opposite surfaces thereof delimiting at least one tongue from the membrane, the tongue being cut-contiguous with the membrane when the membrane is not bulged and projecting, from at least proximate the bead of the membrane, in the direction, between the opposite surfaces of the membrane, extending inwardly from its bead,
• wherein the opposite surfaces of said membrane within said peripheral integral bead are unobstructed so as to permit said membrane to bulge outward in the direction of at least one of said working and equalizing spaces.