Movable seating device and mechanical extension device thereof

A mechanical extension device, comprising:

• a seat frame for attaching a seat of a seating device;
• a backrest assembly pivotally connected to a rear part of the seat frame, wherein the backrest assembly comprises a backrest bracket configured to attach a backrest of the seating device;
• and
• a leg extension device pivotally connected to a front part of the seat frame, wherein the leg extension device is configured to attach an ottoman of the seating device,
• wherein the mechanical extension device is configured to move the seating device from a first position to a second position, wherein the seating device is capable of being in multiple positions comprising a sitting position and a reclining position;
• wherein in the sitting position, the ottoman is located under the seat;
• wherein in the reclining position, the ottoman extends forward and upward, and the backrest tilts backward;
• wherein in the process of moving the seating device from the sitting position to the reclining position, a rear end of the backrest bracket has no component that moves backward;
• and
• wherein the backrest assembly comprises a backrest bracket, a first backrest link, and a second backrest link, the backrest bracket is configured to attach the backrest, the first backrest link is pivotally connected to a front end of the backrest bracket at a first pivot point, the first backrest link is pivotally connected to the seat frame at a second pivot point, and the first pivot point has a trajectory that moves towards the leg extension device in the process of moving the seating device from the sitting position to the reclining position.