Locking mechanism for chair and pushbutton control therefor

摘要

A first chair part may be fixed relative to a second chair part by way of a sliding member attached to the first part which slides in a body attached to the second chair part. The chair parts are fixed relative to each other when a pin associated with the body engages in one of several apertures in the sliding member to fix the chair parts. A bent leaf spring may have an end engaging a collar on the pin. The other end of the leaf spring may be pulled to urge the leaf spring to pivot about a fulcrum created by the bend. However, if there is a force trying to move the sliding member with respect to the body (as may result from a spring between the two chair parts), a consequent shear force on the pin may be sufficiently strong to resist the urging of the leaf spring. In such case, the leaf spring will simply bend when its other end is pulled until the force between the body member and slider is relieved. The other end of the leaf spring may be pulled with an actuator device having a track bearing member with a closed loop track. An actuator member is linked to the other end of the leaf spring and has a track follower received by the track. The actuator member may be pushed against the urging of a spring to move the track follower between first and second locating positions on the track. Movement of the track follower from the first to the second locating position and back again causes no net rotation of the actuator member relative to the track bearing member.