Disclosed is an underframe with an improved structure. The underframe includes an underframe body, an operating handle, a reclining pull rope and a gas spring pull rope, a cushion back-and-forth moving mechanism being installed on the outer side of the underframe body, the operating handle being installed through a left outer wall of the underframe body at a lower end of the cushion back-and-forth moving mechanism, a backrest installed on a rear end of the underframe body through a backrest connecting rod; and a reclining elastic adjusting mechanism is arranged at a front end of an inner wall of the underframe body, a backrest angle adjusting mechanism is arranged at the inner wall of the underframe body on a right side of the reclining elastic adjusting mechanism, a cushion height adjusting mechanism is fixedly connected in the underframe body.

Disclosed is an underframe with an improved structure. The underframe includes an underframe body, an operating handle, a reclining pull rope and a gas spring pull rope, a cushion back-and-forth moving mechanism being installed on the outer side of the underframe body, the operating handle being installed through a left outer wall of the underframe body at a lower end of the cushion back-and-forth moving mechanism, a backrest installed on a rear end of the underframe body through a backrest connecting rod; and a reclining elastic adjusting mechanism is arranged at a front end of an inner wall of the underframe body, a backrest angle adjusting mechanism is arranged at the inner wall of the underframe body on a right side of the reclining elastic adjusting mechanism, a cushion height adjusting mechanism is fixedly connected in the underframe body.

According to an aspect of the present disclosure, a multi-step height adjuster includes a base tube portion including a first base tube and a second base tube vertically reciprocating inside the first base tube; a spindle portion including a first spindle installed inside the first base tube to vertically reciprocate and a second spindle installed inside the second base tube to vertically reciprocate; and an adjustment portion installed in the spindle portion to transmit power to the spindle portion, wherein the first spindle and the second base tube are integrally moved.

According to an aspect of the present disclosure, a multi-step height adjuster includes a base tube portion including a first base tube and a second base tube vertically reciprocating inside the first base tube; a spindle portion including a first spindle installed inside the first base tube to vertically reciprocate and a second spindle installed inside the second base tube to vertically reciprocate; and an adjustment portion installed in the spindle portion to transmit power to the spindle portion, wherein the first spindle and the second base tube are integrally moved.

A quick-release device is for securing a rod of any gas cylinder into the plate of any chair, item of furniture, or other device supported by a gas cylinder and activating the rod with a button thereon. This universal quick-release device includes a sleeve in in the seat plate, an adapter fit into the sleeve, the adapter including an upper portion and a lower portion with different inner and outer diameters. The sleeve is configured to receive the lower portion of the adapter in a press-fit engagement. The upper portion is configured to receive the rod of the gas cylinder in a removable engagement.

A quick-release device is for securing a rod of any gas cylinder into the plate of any chair, item of furniture, or other device supported by a gas cylinder and activating the rod with a button thereon. This universal quick-release device includes a sleeve in in the seat plate, an adapter fit into the sleeve, the adapter including an upper portion and a lower portion with different inner and outer diameters. The sleeve is configured to receive the lower portion of the adapter in a press-fit engagement. The upper portion is configured to receive the rod of the gas cylinder in a removable engagement.

Joystick chair is an input device for interaction between the user and computer. It enables the movement of the user in games. The invention is used by placing feet on the platform (3) and sitting or leaning on the seat (23). Command for turning is achieved by rotating the seat (23), either to the left or to the right. Command for forward movement is issued by pulling the left or right controller (36, 41) with fingers, while the command for backward movement is issued by pushing the left or right controller (36, 41) away by palms. Control handles for lateral movement (49, 56) are separated from the forward-back controls that are located on the controllers (36, 41). Other commands are achieved with buttons on the left and right controller and they are accessible with thumbs. The software allows the modifications of all available actions of the invention.

Joystick chair is an input device for interaction between the user and computer. It enables the movement of the user in games. The invention is used by placing feet on the platform (3) and sitting or leaning on the seat (23). Command for turning is achieved by rotating the seat (23), either to the left or to the right. Command for forward movement is issued by pulling the left or right controller (36, 41) with fingers, while the command for backward movement is issued by pushing the left or right controller (36, 41) away by palms. Control handles for lateral movement (49, 56) are separated from the forward-back controls that are located on the controllers (36, 41). Other commands are achieved with buttons on the left and right controller and they are accessible with thumbs. The software allows the modifications of all available actions of the invention.

A multifunctional swivel chair tray includes a main body. The main body is connected with a warping plate through a second rotating shaft. An ascending and descending block penetrates through the second rotating shaft. The ascending and descending block is connected with an ascending and descending driving mechanism. A first adjusting rod penetrates through one side of the main body. The first adjusting rod is connected with a multi-spring grouping adjusting mechanism. A second adjusting rod is arranged on another side of the main body. The second adjusting rod is connected with a gear adjusting mechanism. The warping plate is connected with a base plate through a third rotating shaft. A slide plate is slidably connected onto the base plate. A slide plate locking mechanism is arranged between the base plate and the slide plate.

A multifunctional swivel chair tray includes a main body. The main body is connected with a warping plate through a second rotating shaft. An ascending and descending block penetrates through the second rotating shaft. The ascending and descending block is connected with an ascending and descending driving mechanism. A first adjusting rod penetrates through one side of the main body. The first adjusting rod is connected with a multi-spring grouping adjusting mechanism. A second adjusting rod is arranged on another side of the main body. The second adjusting rod is connected with a gear adjusting mechanism. The warping plate is connected with a base plate through a third rotating shaft. A slide plate is slidably connected onto the base plate. A slide plate locking mechanism is arranged between the base plate and the slide plate.