Anti-Tip Chair Foot

Abstract

Disclosed is an anti-tip chair leg extension device that is attachable to the foot of a chair leg to prevent or reduce the risk of the chair from tipping over backwards. This feature of the device is especially beneficial when a child is using the chair. The anti-tip leg extension device comprises: a leg socket mounted on a foot plate, grip keys and leg grips. The lower (or foot) portion of a rear leg of the chair leg is received into the leg socket. The leg grip wedge and key grip combination releaseably grips the foot of the chair leg when the chair leg is received in the leg socket. The foot plate then acts to shift the distance of the moment-arm of the chair backward and away from the center of mass of the chair to reduce a tendency of the chair to tip backward.

What is claimed is: 
     
         1 . An anti-tip chair leg extension device ( 10 ) attachable to a foot ( 62 ) of a rear chair rear leg ( 60 ) comprising:
 a foot plate ( 12 ) having a front-portion ( 20 ) and a back-portion ( 22 ), a top-surface ( 24 ) and a bottom surface ( 26 );   a leg socket ( 14 ) into which the rear leg ( 60 ) is receivable, the leg socket ( 14 ) having an upper-end and a lower end, the upper-end having an opening ( 40 ) into which the foot end ( 62 ) of the rear leg ( 60 ) is insertable and the lower-end being mounted to the upper surface ( 24 ) of the foot plate ( 12 ), and having a front-side wedge grip key ( 16 ) for engaging the chair leg ( 60 ) at a lower portion of the foot ( 62 ) of the leg ( 60 ) and a back-side wedge grip key ( 16 ) for engaging the foot ( 62 ) of the chair leg ( 60 ) at an upper portion; and   a leg grip wedge ( 18 ) adapted to engage the wedge key grip ( 16 ) and to releaseably grip the foot ( 62 ) of the chair leg ( 60 ) when the chair leg ( 60 ) is received in the leg socket ( 14 ),   
       in combination to provide the device ( 10 ) adapted to shift the distance of a moment-arm of the chair backward from a center of mass of the chair to reduce a tendency of the chair to rotate backward. 
     
     
         2 . The attachable anti-tip chair leg extension device ( 10 ) of  claim 1 , wherein the lower-end of the leg socket ( 14 ) is mounted to the top surface ( 24 ) of the foot plate ( 12 ). 
     
     
         3 . The attachable anti-tip chair leg extension device ( 10 ) of  claim 1 , wherein the the foot plate ( 12 ) has a recess ( 34 ) in the front portion ( 20 ) of the top surface ( 24 ), the recess ( 34 ) for receiving and mounting the lower-end of the leg socket ( 14 ) to the foot plate ( 12 ). 
     
     
         4 . The attachable anti-tip chair leg extension device ( 10 ) of  claim 1 , wherein the opening of the leg socket has a cross section adapted to closely receive a shape of the foot ( 62 ) of the chair leg ( 60 ). 
     
     
         5 . The attachable anti-tip chair leg extension device ( 10 ) of  claim 1 , wherein the leg socket ( 14 ) is further mounted to the top surface ( 24 ) of the foot plate ( 12 ) by a brace ( 58 ) from the rear-side ( 44 ) of the leg socket ( 14 ) to the top surface ( 24 ) of the foot plate ( 12 ). 
     
     
         6 . The attachable anti-tip chair leg extension device ( 10 ) of  claim 1 , wherein the leg grip ( 19 ) has a wedge shape with detents ( 50 ) arranged as a series of saw-tooth like projections.