Patent ID: 7077250

Claim:
A vibration damper for a machinery mount having a top member, and a bottom member disposed below and spaced from the top member and adaptable to be positioned on a substructure, comprising: (a) a receptacle closed at the bottom and open at the top for vertical disposition on the bottom member so as to have opposed parallel walls as viewed in cross-section, and having a top marginal edge spaced from the top member, thereby defining a chamber adaptable for containing viscous medium; (b) a plunger depending downwardly from the top member for vertical disposition partially within said receptacle and concentric therewith; said plunger having opposed parallel walls as viewed in vertical cross-section, and of the same configuration as said receptacle when viewed in plan, thereby defining a circumferential channel with the walls of the receptacle in which the viscous medium is free to flow, said plunger being spaced from said closed bottom of said receptacle so as to be submerged partially in the viscous medium contained in said chamber, and to be free to reciprocate vertically with reference to said receptacle; (c) a transversely disposed plate member affixed at about the bottom of the plunger, said plate member having a plurality of apertures to provide fluid communication between said receptacle and said plunger, one or more strengthening members disposed within said plunger and between said top member and said plate and affixed thereto, said plunger and said strengthening members having an opening at a location above the viscous medium to allow for the circulation of air, whereby reciprocation of said plunger allows said viscous medium to pass through said apertures and allows movement of said viscous medium in said circumferential channel between the walls of the receptacle and plunger; and (d) a first tube downwardly depending from said top member and spaced between said receptacle and said plunger, a second tube spaced between said first tube and said plunger and extending upwardly from said bottom member, said second tube having an opening at about the level of said viscous medium thereby maintaining an equal level of viscous medium, said first and second tubes of the of the same configuration of said receptacle and said plunger when viewed in plan.