Tuned mass damper

Abstract

A tuned mass damper comprises a mass ( 1 ) restrained to a structure ( 2 ) through supporting means ( 3 ) suitable to allow a pendulum motion of said mass ( 1 ) when said structure ( 2 ) is subject to an external force, as well as damping means suitable for absorbing a portion of the kinetic energy of the moving mass ( 1 ). The supporting means ( 3 ) comprise at least one bearing ( 3 ) provided with a concave cylindrical sliding surface ( 3 a ) and the damping means are made as a coating of a controlled friction material of said sliding surface ( 3 a ).

1 - 14 . (canceled) 
     
     
         15 . A tuned mass damper comprising at least one mass and supporting means restraining said mass to a structure and suitable to allow a pendulum motion thereof when said structure is subject to an external force, said tuned mass damper further comprising damping means suitable for absorbing a portion of the kinetic energy of the mass when in motion, wherein said supporting means comprise at least one bearing and wherein said bearing is provided with a concave cylindrical sliding surface. 
     
     
         16 . The damper of  claim 15 , wherein said supporting means comprise a plurality of bearings having concave cylindrical sliding surfaces of equal curvature and arranged parallel to each other, and wherein said mass is provided with a plurality of feet arranged at positions corresponding to the positions of the bearings. 
     
     
         17 . The damper of  claim 16 , wherein each foot consists of an upper portion restrained to the mass and of a lower portion that has a convex cylindrical surface suitable to contact the concave cylindrical sliding surface of the respective bearing. 
     
     
         18 . The damper of  claim 17 , wherein each foot comprises a cylindrical or spherical cap joint coupling said upper portion to said lower portion of each foot and wherein said cylindrical or spherical cap joint is suitable to allow a relative movement and a relative rotation between the upper portion and the lower portion of each foot. 
     
     
         19 . The damper of  claim 17 , wherein the damping means are made as coatings of controlled friction materials of the concave cylindrical sliding surfaces of the bearings and of the convex cylindrical surfaces of the lower portions of the feet. 
     
     
         20 . The damper of  claim 19 , wherein the bearings and the lower portions of the feet are entirely made of controlled friction materials. 
     
     
         21 . The damper of  claim 19 , wherein said controlled friction materials are stainless steel and polymeric materials selected the group consisting of polyethylene, polyamidic resins and PTFE modified and/or filled. 
     
     
         22 . The damper of  claim 20 , wherein said controlled friction materials are stainless steel and polymeric materials selected the group consisting of polyethylene, polyamidic resins and PTFE modified and/or filled. 
     
     
         23 . The damper of  claim 16 , wherein the sliding surfaces of the bearings have curvature radiuses transversally varying with respect to the direction of motion of the mass, and wherein the damper further comprises driving means suitable for modifying the contact points between the mass and said sliding surfaces. 
     
     
         24 . The damper of  claim 23 , wherein the bearings are arranged in pairs on the structure, the respective sliding surfaces being parallel to each other and having a curvature radius increasing outwards when starting from the plane of symmetry of the damper in which the mass moves, the feet being correspondingly mounted in pairs and movably on guides fixed to the mass and arranged transversally to its motion direction, and wherein said driving means are connected to each pair of feet and are suitable for modifying their relative distance. 
     
     
         25 . The damper of  claim 24 , wherein said driving means comprises a worm, said worm being provided at one end with a maneuvering member suitable to allow the rotation thereof around its axis, the worm having a first threaded portion inserted in a threaded hole formed in the upper portion of a first foot of the pair and a second portion with opposite threading inserted in a threaded hole formed in the upper portion of a second foot of the pair. 
     
     
         26 . The damper of  claim 16 , wherein the bearings are arranged in a multilayer structure, each layer comprising at least a base and one or more bearings as well as a series of feet at positions corresponding to the positions of the bearings, the direction of motion for each layer being defined by the orientation of the sliding surfaces of the one or more bearings arranged thereon. 
     
     
         27 . The damper of  claim 26 , wherein for each layer of said multilayer structure the sliding surfaces of the bearings have curvature radiuses transversally varying with respect to the direction of motion defined by them, and wherein each layer further comprises driving means suitable for modifying the contact points between the feet and the sliding surfaces. 
     
     
         28 . The damper of  claim 26 , wherein in the various layers of said multilayer structure the couplings between the concave cylindrical sliding surfaces of the bearings and the convex cylindrical surfaces of the feet are made with different controlled friction materials. 
     
     
         29 . The damper of  claim 27 , wherein in the various layers of said multilayer structure the couplings between the concave cylindrical sliding surfaces of the bearings and the convex cylindrical surfaces of the feet are made with different controlled friction materials. 
     
     
         30 . The damper of  claim 15 , wherein the mass is equal to 2-4% of the total mass of the structure. 
     
     
         31 . The damper of  claim 18 , wherein the damping means are made as coatings of controlled friction materials of the concave cylindrical sliding surfaces of the bearings and of the convex cylindrical surfaces of the lower portions of the feet.