Stowable stair carrier with lift assist mechanism

Abstract

A system includes a structure having a wall, a doorway and a door that is repositionable between a first position wherein the door is clear of the doorway and a second position wherein the door occludes the doorway. The system also includes a stair carrier attached to the structure. A stair may be connected to the stair carrier. The stair carrier is repositionable between a first position wherein the entirety of the stair carrier is disposed on a first side of the wall and a second positon wherein a portion of the stair carrier extends through the doorway to a second side of the wall. The door is fully operable between the first position and the second position both when the stair carrier is in the first position and in the second position.

1 . A stowable stair assembly cooperable with a doorway of a structure, the stowable stair assembly comprising:
 an actuator mounting bracket securable to the structure;   a base plate fixable to the structure in or adjacent the doorway;   a threshold plate pivotably connected to the base plate via a first hinge, the first hinge defining a first pivot axis, and the threshold plate being pivotable between a deployed position and a stowed position;   a stair connected to the threshold plate;   a lift bracket pivotably connected to the threshold plate; and   an actuator connected between the lift bracket and the actuator mounting bracket, the actuator biasing the lift bracket into engagement with the threshold plate.   
     
     
         2 . A stowable stair assembly according to  claim 1 , wherein the threshold plate comprises a first portion pivotably connected to the base plate and second portion that is perpendicular to the first portion such that the threshold plate is substantially L-shaped. 
     
     
         3 . A stowable stair assembly according to  claim 2 , further comprising attachment tabs extending from the second portion of the threshold plate, wherein the stair is attached to the attachment tabs. 
     
     
         4 . A stowable stair assembly according to  claim 2 , wherein the first portion of the threshold plate includes a second hinge defining a second pivot axis that is spaced from and parallel to the first pivot axis, wherein the lift bracket is pivotably connected to the threshold plate by the second hinge. 
     
     
         5 . A stowable stair assembly according to  claim 1 , wherein the lift bracket comprises a lift portion and a cam portion generally perpendicular to the lift portion, and wherein the actuator is connected between the cam portion of the lift bracket and the actuator mounting plate. 
     
     
         6 . A stowable stair assembly according to  claim 1 , wherein the actuator is a gas strut or a compression spring disposed within a tube. 
     
     
         7 . A stowable stair assembly according to  claim 1 , further comprising adjustable feet selectively extendable beyond a bottom of the stair. 
     
     
         8 . A stowable stair assembly according to  claim 1 , wherein the base plate and the actuator mounting bracket are mounted to the structure so that an axis of the actuator is spaced from the first pivot axis throughout an entire range of motion of the actuator, the lift bracket, and the threshold plate. 
     
     
         9 . A stowable stair assembly according to  claim 1 , further comprising a latch connected to the stair, the latch being configured to engage the structure when the threshold plate is in the stowed position. 
     
     
         10 . A stowable stair assembly according to  claim 1 , wherein the threshold plate overlies base plate in the deployed position. 
     
     
         11 . A stowable stair assembly cooperable with a doorway of a structure, the stowable stair assembly being displaceable between a deployed position and a stowed position and comprising:
 an actuator mounting bracket securable to the structure;   a base plate fixable to the structure in or adjacent the doorway;   a threshold plate pivotably connected to the base plate via a first hinge, the first hinge defining a first pivot axis;   a stair connected to the threshold plate, the stair being pivotable with the threshold plate;   a lift bracket pivotably connected to the threshold plate via a second hinge defining a second pivot axis that is spaced from and parallel to the first pivot axis; and   an actuator connected between the lift bracket and the actuator mounting bracket, the actuator biasing the lift bracket into engagement with the threshold plate,   wherein in the deployed position, the lift bracket is pivoted closer to the actuator by the threshold plate, and the actuator is in a retracted state, and wherein in the stowed position, the lift bracket is pivoted away from the actuator by the threshold plate, and the actuator is in an extended state.   
     
     
         12 . A stowable stair assembly according to  claim 11 , wherein the threshold plate comprises a first portion pivotably connected to the base plate and second portion that is perpendicular to the first portion such that the threshold plate is substantially L-shaped. 
     
     
         13 . A stowable stair assembly according to  claim 11 , wherein the lift bracket comprises a lift portion and a cam portion generally perpendicular to the lift portion, and wherein the actuator is connected between the cam portion of the lift bracket and the actuator mounting plate. 
     
     
         14 . A stowable stair assembly according to  claim 11 , wherein the base plate and the actuator mounting bracket are mounted to the structure so that an axis of the actuator is spaced from the first pivot axis throughout an entire range of motion of the actuator, the lift bracket, and the threshold plate. 
     
     
         15 . A stowable stair assembly according to  claim 11 , further comprising a latch connected to the stair, the latch being configured to engage the structure when the stowable stair assembly is in the stowed position. 
     
     
         16 . A stowable stair assembly according to  claim 11 , wherein the threshold plate overlies base plate in the deployed position. 
     
     
         17 . A method of installing a stowable stair assembly in cooperation with a doorway of a structure, the method comprising:
 (a) securing an actuator mounting bracket to the structure;   (b) fixing a base plate to the structure in or adjacent the doorway;   (c) pivotably connecting a threshold plate to the base plate via a first hinge, the first hinge defining a first pivot axis, wherein the threshold plate is pivotable between a deployed position and a stowed position;   (d) connecting a stair to the threshold plate;   (e) pivotably connecting a lift bracket to the threshold plate; and   (f) connecting an actuator between the lift bracket and the actuator mounting bracket, and configuring the actuator to bias the lift bracket into engagement with the threshold plate.   
     
     
         18 . A method according to  claim 17 , wherein the first portion of the threshold plate includes a second hinge defining a second pivot axis that is spaced from and parallel to the first pivot axis, and wherein step (e) is practiced by pivotably connecting the lift bracket to the threshold plate by the second hinge. 
     
     
         19 . A method according to  claim 17 , wherein the lift bracket comprises a lift portion and a cam portion generally perpendicular to the lift portion, and wherein step (f) is practiced by connecting the actuator between the cam portion of the lift bracket and the actuator mounting plate. 
     
     
         20 . A method according to  claim 17 , wherein steps (a) and (b) are practiced such that an axis of the actuator is spaced from the first pivot axis throughout an entire range of motion of the actuator, the lift bracket, and the threshold plate.