Whether the design belongs to the scope of patent protection needs to be comprehensively judged from the overall visual effect from the perspective of ordinary consumers. From the picture, your modified design is close to the appearance in the patent, and it is very likely to fall into its protection scope.
The fourth patent number you gave is an invention patent. Judging whether it belongs to the scope of protection depends on whether your product covers all the technical features of the patent claim. Excerpts are as follows:
1.？ A unidirectional wheel set structure is characterized by comprising a large roller and a small roller, wherein each of the large roller and the small roller has an axis; A telescopic device, one end of which is installed on the shaft of the big drum and the other end of which is installed on the shaft of the small drum. When the unidirectional wheel set advances with the big wheel, the telescopic device can keep the small wheel away from the big wheel; when the big wheel rotates reversely, the telescopic device can make the small wheel approach and contact the big wheel, and then lean against the big wheel to prevent the small wheel and the big wheel from rotating. ?
If each of the above features can be found in the same place in your product, it belongs to the protection scope of the invention patent.
2. Whether the patent number can be marked.
According to the Measures for Marking Patent Marks, within the validity period of the patent right after the patent right is granted, the patentee or the licensee who has the right to mark the patent mark with the consent of the patentee may mark the patent mark on the patented product, the product directly obtained according to the patent method, the packaging of the product or the instruction manual of the product.
For non-patentees, no matter whether your product belongs to the scope of patent protection or not, as long as the licensee does not enjoy the patent identification right with the consent of the patentee, it is not allowed to mark the patented product and patent number on the product, manual and packaging, otherwise it is an illegal act of counterfeiting patents.
3. Countermeasures and suggestions
1) Obtain the permission of the patentee; 2) Request the Patent Office to declare the above patent invalid; 3) Advocate the defense and preemptive right to the existing technology; 4) modify the design to bypass the above patents.