At a glance
| Patent number | CN113090903B (application CN202110345227) |
| Type | China invention patent (发明专利) - protects product shape, structure and method |
| Original title | Extensible supporting leg and unipod (一种可延伸的支撑腿及独脚架) |
| Patent owner | Dongguan Yangcong Network Technology Co ltd |
| Inventors | Liang Zhihao, Xiao Shuang |
| Filing date | 2021-03-31 |
| Grant date | 2022-11-15 |
| Status (China) | In force in China until at most 2041-03-31 (if annual fees are paid) |
| Patent family | Chinese filings only - no US, European, Japanese, PCT or other filings listed |
| Cited by | 2 later documents |
| Source | Google Patents (search for CN113090903B) |
What the claims cover, in plain language
Claim 1 - an extendable support leg with two or more leg sections that slide axially. A tensioning assembly (expansion assembly) sits on the second and third sections to lock and release position. A control assembly on the first section operates the tensioning assembly via a transmission rod. The tensioning assembly includes a transmission seat, an extrusion sleeve block, and a fixed seat threaded together. Expansion blocks spaced around the fixed seat are pushed outward by the sleeve block, pressing friction gaskets against the tube wall. Elastic sleeves surround the blocks. Inclined planes on the blocks and sleeve block guide the movement. Balls in annular grooves between the pressing table and sleeve block reduce friction.
Claims 2-3 - specify the first extrusion inclined planes on the lower edge of the sleeve block and the second extrusion inclined planes on a loop platform of the transmission seat, matching the expansion blocks one-to-one.
Claims 4-5 - the expansion blocks have accommodating grooves for the elastic sleeves; two grooves (upper and lower) hold two elastic rings.
Claim 6 onward - the control assembly details: a control base, control shaft body, control bevel gear, and hand-piece. The transmission rod has a transmission bevel gear meshing with the control bevel gear. A swing arm with a positioning assembly uses a spring and steel ball.
This is a simplified reading for orientation only. The legal scope is defined by the exact claim wording in the official Chinese document.
What this means for US production
This patent was filed only in China and is in force in China until at most 2041-03-31 (if annual fees are paid). Making or selling this specific leg design in China needs the owner’s permission. It has no US or other foreign counterpart.
Two points to settle early:
- Other patents may exist. Guangdong Sirui Optical Co., Ltd. holds a later US patent (US20240337348A1) citing this document, indicating active patenting in the camera support field. Other makers of photographic stands hold US patents covering internal locking rods and expanding collets, so a freedom-to-operate (FTO) review of the transmission rod, bevel gear control, and expanding block mechanism is needed before tooling.
- Tube dimensions and tolerances. The friction lock relies on precise gaps between the expansion blocks, gaskets, and inner tube walls; diameters and wall thicknesses must be confirmed on prototypes to ensure reliable holding force without binding.
Customization and manufacturing
What can be customized
| Area | Options |
|---|---|
| Number of sections | Two, three, or more telescoping tubes |
| Tube material | Aluminum alloy, carbon fiber composite (outer shell with internal liner) |
| Length | Collapsed and extended lengths set in design / confirmed on prototypes |
| Gasket material | Rubber, plastic, or abrasion-proof cloth pads |
| Hand-piece style | Knob shape, folding lever, or textured grip |
| Top mount | Standard camera screw thread size to be confirmed in design |
| Surface finish | Anodized, painted, or bare metal |
Things to plan for (US market)
- FCC rules do not apply unless electronic motors or wireless features are added to the control assembly.
- California Prop 65 - anodizing chemicals, rubber gaskets, and plastics must be screened for listed substances.
- General product safety - no specific CPSC standard covers camera monopods, but pinch points in the telescoping sections should be evaluated under general duty of care.
How a project runs
- Inquiry - target collapsed length, extended length, load capacity, materials, and quantity.
- Design - tube diameters, transmission rod length, gear ratio, expansion block geometry, and gasket selection.
- Prototype - CNC-machined samples to verify the locking force, release smoothness, and section alignment.
- Pilot run - small batch for drop tests, cycle tests on the expansion mechanism, and torque testing on the control assembly.
- Production - tube extrusion or rolling, machining of seats and blocks, gear cutting, gasket molding, and final assembly.
Quantities & timeline
The tubes require extrusion dies or carbon-fiber mandrels per diameter, the transmission seats, fixed seats, and extrusion sleeve blocks need precision machining or metal injection molds, and the bevel gears require hobbing tools. Cycle testing the expansion blocks and tuning the elastic sleeve tension take most of the development time. Send us your target lengths, load requirements, material preferences, quantity and timeline and we will reply with options.
Patent drawings
Drawings reproduced from the public patent document for reference.
