Patent ID: 9494209
Filing Date: 2016-11-15
CPC Classification: F16F

Claim Text:
1. A hydraulic damper, comprising: a first housing defining a cavity for hydraulic fluid; a first piston slidable within the cavity and dividing the cavity into a first volume and a second volume; a rod extending from the cavity, said first piston being attached to said rod, said rod including an internal passageway for flow of hydraulic fluid between said first volume and said second volume; a second housing in fluid communication with the first volume and fixedly attached to said rod, said second housing including an internal chamber and a second piston slidable within the chamber between a first position and a second position; and a spring for biasing said second piston to the first position; wherein in the first position there is a first flow path for the flow of hydraulic fluid from the first volume through the internal passageway and into the second volume, in the second position there is a second flow path for the flow of hydraulic fluid from the first volume through the internal passageway and into the second volume, and the first flow path is more restrictive than the second flow path; wherein said second piston is actuated to the second position by hydraulic pressure when pressure in the first volume is higher by a predetermined amount than pressure in the second volume; wherein the second piston has a surface area, and in the first position a first portion of the surface area is exposed to pressure from the first volume and the remainder of the surface area is not exposed to pressure from the first volume, the first portion coacting with pressure from the first volume to move said second piston toward the second position, and wherein in the second position pressure from the first volume coacts with the first portion and the remainder of the surface area to maintain said second piston in the second position; wherein said second piston includes a flow orifice located within the remainder of the surface area for flow of hydraulic fluid from the first volume into the second volume.