This article analyses a landmark utility patent infringement case heard by the Jiangsu Provincial Higher People’s Court under the Patent Law of the People’s Republic of China (2020 Amendment). All corporate names are anonymized for commercial confidentiality: the patentee is Horizon Machinery Co., Ltd., and the alleged infringer is Peak Manufacturing Co., Ltd. The judgment clarifies the practical application of the doctrine of equivalents in Chinese patent trials, restricts the common defence strategy of “minor structural modification to avoid infringement”, and provides essential compliance guidance for domestic machinery manufacturers engaged in product imitation and structural optimization.
Horizon Machinery completed the research and development of an automatic raw material cutting device in 2019 and obtained a granted Chinese utility patent. A Chinese utility patent protects new technical solutions relating to the shape, structure or combination of products, with a protection term of ten years counted from the filing date. The independent claim defined a core assembly structure composed of a movable limiting block, elastic reset component and sliding guide rail. This structural design effectively solved the problem of raw material offset during high-speed cutting and reduced product reject rates. The patentee invested heavily in mould production and market promotion, supplying cutting equipment to processing factories nationwide. Horizon strictly prohibited unauthorized copying, manufacturing and sales of equipment adopting the patented structural scheme.
In early 2022, Horizon’s market investigators found that Peak Manufacturing produced and sold similar automatic cutting equipment at a much lower price on B2B industrial platforms. After purchasing equipment samples, completing notarization and carrying out technical disassembly comparison, the patentee confirmed suspected infringement. Peak Manufacturing copied the overall framework of the patented device and only replaced the integrated elastic reset spring with a split elastic rubber cushion, without obtaining any written patent licensing authorization. Horizon issued a cease-and-desist letter, demanding the defendant halt production and sales and negotiate economic compensation. Peak refused the request and put forward a core defence: the replacement of elastic components formed a completely different technical solution, so its products did not fall within the patent protection scope.
In mid-2022, Horizon filed a patent infringement lawsuit before the Nanjing Intermediate People’s Court. Under Chinese judicial rules for patent disputes, courts adopt the “all technical features rule” when judging infringement. If the alleged product contains all identical or equivalent technical features recorded in patent claims, it shall be deemed to fall into the patent protection scope. Equivalent features refer to technical features that adopt substantially identical means, realize substantially identical functions and achieve substantially identical effects, which a person skilled in the relevant field can conceive without creative labour at the time of infringement.
During the first instance trial, Peak insisted that the shift from metal spring to rubber cushion changed the reset driving mode and avoided equivalent infringement. The patentee appointed mechanical engineering experts to issue a technical appraisal report. The appraisal result showed that both the spring and rubber cushion played the identical elastic reset function for the limiting block; the material replacement only brought minor differences in service life and vibration absorption and did not change the core working principle and expected technical effects of the whole equipment. The first instance court ruled that the replaced elastic component constituted an equivalent technical feature, and the equipment manufactured by Peak fell into the protection scope of the involved utility patent. The court ordered the defendant to stop infringement and pay compensation of RMB 320,000.
Dissatisfied with the first-instance judgment, Peak Manufacturing filed an appeal to Jiangsu Higher People’s Court, repeatedly emphasizing structural differences and requesting to overturn the original verdict. The higher court reviewed technical comparison materials, expert opinions and on-site test records comprehensively. The appellate court confirmed that the core connection mode, sliding structure and limiting working logic remained consistent with the patented scheme. Simple replacement of easily interchangeable parts cannot break the equivalent relationship between technical features; partial material adjustment cannot constitute effective non-infringement defence. The higher people’s court rejected the appeal and upheld the original judgment. The defendant decided not to apply to the Supreme People’s Court for retrial, and the judgment became legally binding.
This case eliminates a long-standing misunderstanding among domestic machinery manufacturers. Enterprises cannot evade patent liability merely by replacing individual parts, adjusting installation positions or slightly changing assembly structures. Many factories believe that partial modification of imitated products can avoid infringement identification. However, consistent judicial practice in Chinese IP courts shows that superficial adjustments of replaceable components usually cannot get rid of equivalent infringement findings. Before launching new equipment, manufacturers should conduct professional Freedom-to-Operate (FTO) patent searches to assess risks of falling into others’ patent protection scope.
Furthermore, enterprises should master two effective defensive tools when facing patent lawsuits.
Defendants can file an invalidation request against the involved patent with the China National Intellectual Property Administration (CNIPA) within a statutory period. Meanwhile, the existing technical defence can be adopted if the technical scheme has already been publicly disclosed before the patent filing date. It is noteworthy that filing a patent invalidation application does not automatically suspend ongoing civil infringement litigation. Enterprises need to coordinate litigation strategies reasonably to avoid passive situations in court.
For patentees, standardized evidence preservation determines the success rate of rights protection. Notarized purchase of infringing products, equipment disassembly records, technical comparison reports and sales data can form a complete evidence chain. Once continuous large-scale infringement is discovered, rights holders can apply to the court for pre-litigation preservation measures to prevent further expansion of losses. With the continuous tightening of patent protection for industrial equipment in China, mechanical manufacturers must attach importance to independent research and development or formal licensing rather than adopting low-cost imitation plus minor modification strategies.
Four valid, publicly accessible hyperlinks:
1. Official Website of China National Intellectual Property Administration (CNIPA): https://www.cnipa.gov.cn/en
2. WIPO Lex Full Text of the Patent Law of China (2020 Revision): https://www.wipo.int/wipolex/en/text/585084
3. Supreme People’s Court of China Intellectual Property Judicial Platform: https://en.court.gov.cn/
4. China and Multinational Patent Retrieval System: https://cponline.cnipa.gov.cn/
