Vertically Adjustable Automatic Step Stool

Abstract

A step stool includes an inner frame, an outer frame, an actuator, and a coupler. The inner frame includes two inner pillars, and the outer frame includes two outer pillars attached to a platform near opposite ends of the platform and configured to receive the two inner pillars. The actuator is coupled to one of the two inner pillars and one of the two outer pillars, and is operable to raise the outer frame relative to the inner frame. The coupler couples the two outer pillars to each other to evenly lift the opposite ends of the platform when the actuator raises the outer frame.

What is claimed is: 
     
         1 . A step stool, comprising:
 an inner frame including two inner pillars;   an outer frame including two outer pillars attached to a platform near opposite ends of the platform and configured to receive the two inner pillars;   an actuator coupled to one of the two inner pillars and one of the two outer pillars, and operable to raise the outer frame relative to the inner frame; and   a coupler that couples the two outer pillars to each other to evenly lift the opposite ends of the platform when the actuator raises the outer frame.   
     
     
         2 . The step stool of  claim 1 , wherein the coupler includes a chain meshed with a sprocket, the chain having a first end fixed to a first of the two outer pillars and a second end fixed to a second of the two outer pillars. 
     
     
         3 . The step stool of  claim 2 , wherein the chain and the sprocket are arranged to transmit an upward force on the second of the two outer pillars when the actuator exerts an upward force on the first of the two outer pillars. 
     
     
         4 . The step stool of  claim 2 , further comprising a tensioner adjustable to adjust the tension of the chain. 
     
     
         5 . The step stool of  claim 1 , further comprising a sliding mechanism including a first bracket, a second bracket, and a bearing, the first bracket mounted to the inner frame, the second bracket mounted to the outer frame, and the bearing positioned between the first bracket and the second bracket. 
     
     
         6 . The step stool of  claim 1 , wherein the actuator includes a motor, a cylinder, and a piston, the motor operable to slide the piston within the cylinder. 
     
     
         7 . The step stool of  claim 6 , further comprising a control module and a user interface, the control module controlling the motor to raise and lower the platform based on commands received from a user via the user interface. 
     
     
         8 . The step stool of  claim 7 , further comprising an object sensor mounted to the inner frame, wherein the control module stops the motor when the object sensor senses objects beneath the platform. 
     
     
         9 . The step stool of  claim 1 , further comprising a handle on each of the two outer pillars. 
     
     
         10 . The step stool of  claim 1 , further comprising wheels coupled to the inner frame that enable a user to roll the step stool to a desired position. 
     
     
         11 . The step stool of  claim 10 , further comprising brakes that prevent the wheels from rolling. 
     
     
         12 . The step stool of  claim 1 , further comprising a brace mounted to the inner frame and engaging the actuator to prevent the actuator from tilting. 
     
     
         13 . A step stool, comprising:
 an inner frame including a single inner pillar;   an outer frame including a single outer pillar attached to a platform near a first end of the platform and configured to receive the inner pillar;   an actuator coupled to the inner pillar and the outer pillar, and operable to raise the outer frame relative to the inner frame; and   a coupler that couples the outer pillar and a second end of the platform to evenly lift the first end of the platform and the second end of the platform opposite the first end of the platform when the actuator raises the outer frame.   
     
     
         14 . The step stool of  claim 13 , wherein the coupler includes a chain meshed with a sprocket, the chain having a first end fixed to the outer pillar and the second end fixed to the platform. 
     
     
         15 . The step stool of  claim 14 , wherein the chain and the sprocket are arranged to transmit an upward force on the second end of the platform when the actuator exerts an upward force on the outer pillar. 
     
     
         16 . The step stool of  claim 15 , wherein the sprocket includes multiple sprockets and one of the sprockets is position at the second end of the platform. 
     
     
         17 . The step stool of  claim 16 , wherein the upward force on the second end of the platform is transmitted through a pivot of the one of the sprockets. 
     
     
         18 . The step stool of  claim 13 , further comprising a control module and a user interface, the control module controlling a motor to raise and lower the platform based on commands received from a user via the user interface. 
     
     
         19 . The step stool of  claim 18 , wherein the control module is mounted to the inner frame underneath the platform and the user interface is integrated in the outer pillar. 
     
     
         20 . A step stool, comprising:
 an inner frame including two inner pillars;   an outer frame including two outer pillars attached to a platform near opposite ends of the platform and configured to receive the two inner pillars;   an actuator coupled to one of the two inner pillars and one of the two outer pillars, and operable to raise the outer frame relative to the inner frame;   a slide mechanism including a first bracket, a second bracket, and a bearing ball, the first bracket mounted to the inner frame, the second bracket mounted to the outer frame, and the bearing ball positioned between the first bracket and the second bracket; and   a chain and sprocket mechanism that couples the two outer pillars to each other to evenly lift the opposite ends of the platform when the actuator raises the outer frame.