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 receiver mounted on a footplate, and a grip means. The lower (or foot) portion of a rear leg of the chair leg is received into the leg receiver. The grip means (releaseably) holds the foot of the chair leg in place when the chair leg is received in the leg receiver. The footplate 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 receiver ( 14 ) into which the rear leg ( 60 ) is receivable, the leg receiver ( 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 receiver ( 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 receiver ( 14 ) is mounted to the top surface ( 24 ) of the footplate ( 12 ). 
     
     
         3 . The attachable anti-tip chair leg extension device ( 10 ) of  claim 1 , wherein 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 receiver ( 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 receiver 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 receiver ( 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 receiver ( 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. 
     
     
         7 . An anti-tip chair leg extension device ( 10 ) attachable to a foot ( 62 ) of a rear chair rear leg ( 60 ) comprising:
 a footplate ( 12 ) having a top-surface ( 24 ) and a bottom surface ( 26 );   a leg receiver ( 14   a ) into which the foot end ( 62 ) of the rear leg ( 60 ) is receivable, the leg receiver ( 14   a ) having leg clamp mounting means ( 98 ) and a lower end which is pivotably connected to the footplate ( 12 );   a bendable joint ( 112 ) pivotably connecting the footplate ( 12 ) to the leg receiver ( 14   a ); and   a leg clamp ( 17 ) means adapted to grip and secure the chair leg ( 60 ) to the leg receiver ( 14   a )   
       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. 
     
     
         8 . The anti-tip chair leg extension device ( 10 ) of  claim 7 , wherein the bendable joint ( 112 ) pivotably connecting the footplate ( 12 ) to the leg receiver ( 14   a ) is a pin-and-knuckle joint ( 112   a ). 
     
     
         9 . The anti-tip chair leg extension device ( 10 ) of  claim 7 , wherein the bendable joint ( 112 ) pivotably connecting the footplate ( 12 ) to the leg receiver ( 14   a ) is a bendable metallic joint ( 112   b ). 
     
     
         10 . The anti-tip chair leg extension device ( 10 ) of  claim 7 , wherein the bendable joint ( 112 ) pivotably connecting the footplate ( 12 ) to the leg receiver ( 14   a ) is a bendable plastic joint ( 12   c ). 
     
     
         11 . The anti-tip chair leg extension device ( 10 ) of  claim 7 , wherein the footplate ( 12 ) includes fastening means for engaging the chair foot ( 62 ) to prevent the footplate ( 14   a ) from drooping about the joint ( 112 ).