Chair

Abstract

A chair structure results in a proper counter force when an occupant reclines on a back. The chair is composed of a pintle, a base which is supported by the pintle, a back support which is installed on the back, a seat support which is installed on a seat, a first swaying pivot, a second swaying pivot which is located in front of the first swaying pivot, a third swaying pivot which is located between the first swaying pivot and the second swaying pivot, and a sliding structure. The chair is provided with simple structures, and can result in a constant counter force or maintain a proper counter force depending on an angle of the back, when the occupant reclines on the back.

1 . A chair comprising a pintle; a base, which is supported by the pintle; a back support, which is installed on a back; a seat support, which is installed on a seat; a first swaying pivot, which is located on the base, and is connected with the back support in a manner that the back support is tilted rearwards; a second swaying pivot, which is located in front of the first swaying pivot, is at a same level as that of the first swaying pivot, is displaced upwards or above the first swaying pivot, and connects the seat support to the base in a manner that the seat support is tilted upwards and downwards; a third swaying pivot, which is located between the first swaying pivot and the second swaying pivot, is displaced at a level higher than that of a connecting line that connects the first swaying pivot and the second swaying pivot, so as to connect the back support with the seat support to be tilted upwards and downwards, and to be linked with rearward tilt of the back support such that the third swaying pivot raises with the back support; and a sliding structure, which is linked with rising of the third swaying pivot, allowing the second swaying pivot to be guided along a rear upper slant direction. 
     
     
         2 . The chair according to  claim 1 , wherein the sliding structure guides the second tilting structure in a straight line, or to be protruded out of an arc at an underside. 
     
     
         3 . The chair according to  claim 1 , wherein the base is provided with a locking structure to fix the back support. 
     
     
         4 . The chair according to  claim 2 , wherein the base is provided with a locking structure to fix the back support. 
     
     
         5 . The chair according to  claim 3 , wherein the locking structure is provided with a swaying unit to fix the back support, a support arm to sway the swaying unit, and an operating structure to displace the support arm; on the support arm, and under a condition that sway of the swaying unit is restricted, when the operating structure being operated, and an elastic deformation being formed to absorb a displacement of the sway of the swaying unit for accumulating energy, thereby enabling the swaying unit to sway. 
     
     
         6 . The chair according to  claim 4 , wherein the locking structure is provided with a swaying unit to fix the back support, a support arm to sway the swaying unit, and an operating structure to displace the support arm; on the support arm, and under a condition that sway of the swaying unit is restricted, when the operating structure being operated, and an elastic deformation being formed to absorb a displacement of the sway of the swaying unit for accumulating energy, thereby enabling the swaying unit to sway.