Patent ID: 9447624
Filing Date: 2016-09-20
CPC Classification: E05F

Claim Text:
1. A step-plate mechanism, the step-plate mechanism comprising: two step plates being disposed on a floor at both front and back sides of a door, each step plate including a plurality of bearings; multiple links, one end of each link being coupled to a respective one of the bearings of the step plates, wherein each bearing is disposed in a metal part fixed on the floor, and an opposing end of each of the links being coupled to a respective one of the step plates, wherein the step plates, while remaining horizontal, move downward arcuately in a direction of a downward force applied to at least one of the step plates, a return mechanism is provided to bias the links from a displaced position, wherein the ends of the links coupled to the step plates are positioned obliquely downward due to the force applied to the at least one of the step plates to an original position of the ends of the links coupled to the step plates without the force applied to at least one of the step plates, so that the step plates, which move downward due to the force applied to the at least one of the step plates, return to the step plates to an original position thereof after the force is removed from the at least one of the step plates, and wherein one of the step plates has an interlock guide and the other of the step plates has a member configured to receive and slidably connect with the interlock guide, and wherein, when one of the step plates moves downward toward the door in an arcuate path occurring at a constant rate, the other of the step plates also moves downward toward the door in an arcuate path at the constant rate, wherein the movement of the step plates is symmetrical relative to a plane defined by the door, wherein an upper end of the door is slidably hung on an overhung-door rail, and the overhung-door rail is inclined downward in either an opening direction or a closing direction of the door; a guide provided on the door and being inclined upward in a direction for the overhung-door rail to move down; and a drive arm provided on the guide, wherein one end of the drive arm is connected to the interlock guide and an other end of the drive arm is slidably connected to a groove of the guide, wherein when the step plates are stepped on and move down, the other end of the drive arm moves up, thereby raising and sliding the door in the opening direction.