1. The design requirements for the activity stand should meet:
(1) In addition to bearing the weight of the seats themselves, the stands can also withstand the following loads: a dynamic load of 450kg per square meter and a lateral swing load of 36kg per meter.
(2) The guardrail design is designed to withstand horizontal forces as follows: the top can withstand 65kg per meter, and the middle of the guardrail can withstand 135kg per meter.
(3) Stand strength: Stand frame strength: Static load per seat ≥ 200kg; Bed frame impact resistance strength: Static load per seat ≥ 200kg. Intermediate load per layer ≥ 80kg, 300mm height impact does not deform. Under the action of dynamic loads, the overall structure is stable and the bearing surface does not deform.
(4) There are safety railings on both sides and the back edge of the grandstand, with a surface sprayed with plastic, which do not need to be inserted or removed during the expansion and contraction process of the activity grandstand.
(5) The front of the stands has a beautiful appearance, and there are anti slip strips installed on the steps of the stands to prevent the audience from slipping when going up and down.

2. System Material Description
(1) Casters: Wide width PU wheels are used. The inner layer adopts double ball bearings, with a nylon layer in the middle, and then covered with a high toughness and wear-resistant polyurethane layer, which can withstand huge forces without wearing down the floor.
(2) Drive wheel: With multiple reinforced PU structures, it provides the necessary driving friction for the stands, easily overcomes ground defects, meets the needs of stand use, and does not wear down the floor.
(3) Expansion feet: The number of expansion feet in each row can be set according to the size and requirements of the site. Each telescopic foot is equipped with three or more casters, which can roll on the floor without damaging the floor or leaving any rolling marks.
(4) Skeleton: It adopts a composite structure and is made of alloy steel. There shall be no welding in the middle of the members of all load-bearing components. The steel plate thickness of the supporting components shall be ≥ 2.5mm, and they shall be connected by high-strength positioning profiles. It can increase the strength and toughness of materials, improve their mechanical properties, and enhance the stability of structures. The load-bearing crossbeam has a size of 50 × 40 × 2.5, and the column has a size of 100 × 50 × 3. It is installed at a center distance of about 70cm and welded between the main beam and the auxiliary beam. Cold rolled steel plates with sufficient load-bearing capacity are used, which are folded and then sprayed with plastic to provide both good corrosion resistance and a smooth and polished outer surface. Adopting national standard high-strength bolts for on-site riveting (all screws and nuts are standard parts), changing the previous welding drawbacks, making it have both good corrosion resistance and stability, as well as a smooth and polished outer surface. The secondary beam adopts 60 × 40 × 2 internally rolled profiles as structural elements for all wooden support arms and walking surfaces. The support arms between the supporting structures are applied to the main beam to eliminate sliding friction and lubricate the rollers and nails through mechanical surfaces.
(5) Activity Steps: The keel of the activity steps is welded with carbon steel profiles for support, and the pedals are made of 17mm thick high-strength laminated composite solid wood board and 1mm thick melamine wear-resistant board. The surface layer is fixed to the stand auxiliary bracket with rivets, ensuring high strength and structural stability of the movable steps.
(6) Frontier: Adopting special aluminum titanium alloy edging and equipped with special anti slip lines to increase the strength of the bed frame and prevent viewers from slipping while walking. Simultaneously adding anti slip stripes to enhance friction and increase safety factor.
(7) Synchronous telescopic device: Adopting a double-layer guiding design, each driving device is connected by a steel shaft, and the grandstand support structure adopts a mechanical feedback synchronous telescopic device to ensure synchronous extension and retraction without directional deviation. The support legs of the grandstand wheels are made of fixed pull profiles and designed with guide grooves. A synchronous pulley guide mechanism is added to each meter of the upper layer of each grandstand to ensure balanced linear motion during expansion, contraction, and braking without noise.
(8) Stand seats:
Seat: It is a hollow blow molded front folding plastic folding chair. The overall design of the seat conforms to ergonomic principles and adopts a front mounted installation. The width of each level of the grandstand is 800mm, the height is 350mm, and the center distance of the seat installation is 500mm. The driving method is electric, using wireless remote control or wired handle control. The chair surface is manufactured using hollow blow molding technology, using high-density polyethylene material (HDPE) for one-time processing and molding. It has the characteristics of smooth and angular surface of the seat, concentrated molecular weight, high bonding strength at the joint seam, excellent aging resistance, and impact resistance. The surface of the seat is balanced, without poor plasticization, cracks, holes, oil stains, deformation and other defects. The color is uniform and there is no obvious color difference.
① The dimensions of the chair surface are: seat width x seat depth x seat back height=440 x 560 x 500 (mm), and the thickness of the seat wall is not less than 3mm.
② The seat can carry over 200kg and is impact resistant.
③ Seat static load: The seat surface is loaded with over 1600N, and the backrest is loaded with over 760N.
④ Seat durability: The seat can be loaded with 950N x 200000 times or more.
⑤ The seat is resistant to high and low temperatures:+75 ℃ to -50 ℃. No appearance changes such as cracks, spots, bubbles, or obvious deformations, and no local powdering cracks, spots, bubbles, or obvious deformations.
⑥ The service life of the seat is greater than 10 years.
(9) Stand aisle: Each floor is equipped with a box shaped step (with the same craftsmanship as the stand platform).
(10) Locking and handling system: The locking system uses equipment at the corner of the column and is designed to prevent the trolley from moving.
(11) Spraying: Steel components are all electrostatically sprayed on an automatic spraying line to enhance their corrosion resistance. A spraying program is to oxidize and spray powder coating through electrostatic action at approximately 190 degrees Celsius for 20 minutes. The color is determined by the project manager.

3. Power and power system description:
(1) During operation, a movable control switch can be used to execute forward and backward movements.
(2) Imported reduction motors are used to drive gear transmission, and special wide PU friction wheels are used to rub against the floor to drive the movement of the stands. All motors in each section are equipped with independent modules for expansion and contraction, and special codes are used to ensure absolute parallelism between modules. Each code is controlled by a computer system.
(3) The driving system can ensure sufficient power and prevent movement deviation when encountering ground defects and obstacles.

Drive mechanism: adopts electric control type, with two functions of infrared remote control and limited manual control. Adopting imported three-phase reduction motor with electric power of 0.75KW and voltage of 380V, it has the characteristics of large reduction ratio, high efficiency, low noise, few faults, and long service life. Equipped with anti deviation devices to ensure easy and smooth expansion and contraction of the activity stand, without any deviation or other issues. The telescopic mechanism has flexible movements, low working noise, and does not scratch the floor.