At a glance
| Patent number | CN107756342B (application CN201711121100) |
| Type | China invention patent (发明专利) - protects product structure and method |
| Original title | Garden tool working arm folding device (园林工具工作臂折叠装置) |
| Patent owner | Zhejiang Zhongjian Technology Co., Ltd. |
| Inventors | Zhang Hua, Yang Haiyue |
| Filing date | 2017-11-14 |
| Grant date | 2024-01-19 |
| Status (China) | In force - valid until at most 2037-11-14, provided annual fees are paid |
| Patent family | Chinese filings only - no US, European, Japanese, PCT or other filings listed |
| Cited by | 0 later documents (Note: Foreign patents citing this include Black & Decker US11369057B2 and Techtronic EP4729243A1) |
| Source | Google Patents (search for CN107756342B) |
What the claims cover, in plain language
Claim 1 describes a folding device for a garden tool working arm comprising a fixed pipe (1) and a movable pipe (7). Between them is a folding fixing mechanism consisting of a connecting pipe seat (2) and a guiding connecting sheet (3). Key structural elements include:
- The connecting pipe seat (2) has a necking groove (15) with hanging lugs (8) on either sides, holding a fastening piece.
- The guiding connecting sheet (3) is fixed to the movable pipe (7) via an anchor ear (6). It has a protruding portion (14) with a vertex (18).
- The guide sheet (3) and the central section of the movable pipe (7) are coplanar.
- The guide sheet (3) has a guide groove (4) and moves along the fastening piece between the lugs.
- In the fixed connection state, the guide sheet matches the necking groove to guide the movable pipe, maintaining insertion angle. The protrusion (14) inserts into the necking groove, and its vertex (18) inserts into a fixed notch (12) on the movable pipe, preventing rotation.
- An elastic bolt (13) on the seat engages a locking hole (16) on the movable pipe to prevent axial movement and rotation.
- The fastening piece includes a bolt (9) and a knob (5).
- In the folded connection state, the movable pipe is pulled out and rotates around the fastener via the guide groove.
Claim 2 specifies that the connecting pipe seat (2) is fixed to the fixed pipe (1) by contracting the necking groove (15) via screws through the hanging lugs (8).
Claim 3 adds that the fixed pipe (1) has a fixing hole (10) and the seat (2) has a screw (11) that matches this hole to secure the seat to the fixed pipe.
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 currently in force. Making or selling this specific folding mechanism in China requires the owner’s permission. However, since there are no corresponding US patents, the design itself does not infringe on current US patent rights based solely on this document.
Two points to settle early:
- Other patents may exist. Major power tool manufacturers like Black & Decker and Techtronic (owner of Ryobi/Milwaukee brands) have cited this patent in their own filings (e.g., US11369057B2, EP4729243A1). This indicates they are aware of this technology and may have developed alternative or improved folding mechanisms protected in the US. A freedom-to-operate (FTO) review is essential to ensure your implementation does not infringe on these newer US patents.
- Material and Tolerance Sensitivity. The interaction between the elastic bolt, locking hole, and guide groove relies on precise tolerances to function smoothly without binding. Material selection (plastic vs. metal for the guide sheet) will affect wear rates and longevity.
Customization and manufacturing
What can be customized
| Area | Options |
|---|---|
| Pipe Diameter | Adjustable to match existing tool lines (e.g., 22mm, 25mm, 30mm common garden tool standards). |
| Fold Angle | The range of motion can be limited by stops in the guide groove to prevent over-rotation. |
| Locking Strength | Spring rate of the elastic bolt and depth of the locking hole can be tuned for different vibration levels. |
| Finish | Powder coating, anodizing, or plating for corrosion resistance. |
| Knob Design | Ergonomic shapes, larger diameters for gloved hands, or integrated hex keys for backup tightening. |
| Materials | Aluminum alloy for lightweight tools; steel for heavy-duty commercial applications. |
Things to plan for (US market)
- ANSI B71.1 - Safety requirements for powered walk-behind lawn mowers and similar equipment; while this is an accessory/joint, the overall tool must meet vibration and sharp-edge standards.
- UL Standards - If the tool is electric/battery-powered, the joint material must comply with flammability ratings (e.g., UL 94 for plastics).
- California Prop 65 - Lead and cadmium restrictions apply to metal finishes and solder used in assembly.
- CPSC General Product Safety - Ensuring no pinch points or sharp edges occur during the folding/unfolding action.
How a project runs
- Inquiry - Specify pipe diameters, target tool types, and volume.
- Design Adaptation - Adjust the necking groove and guide sheet dimensions to fit your existing pipe inventory.
- Prototype - CNC machined samples for functional testing (fold cycles, lock retention).
- Testing - Vibration tests, drop tests, and salt spray corrosion tests.
- Production - Injection molding for plastic components (seat, sheet), stamping/machining for metal pipes and bolts, assembly.
Quantities & timeline
Injection molds for the connecting seat and guide sheet are required. Metal stamping dies for the anchor ears and lugs. Testing for fatigue life (cycles of folding/unfolding) takes time. Send us your pipe specifications, target tool application, quantity, and desired finish and we will reply with options.
Patent drawings
Drawings reproduced from the public patent document for reference.
