This article's primary goals are to provide design drawings, a description of the structure, an explanation of the working principle, and a kinematics calculation for text stamping machines. This machine has an electric motor, a gear-pinion transmission, a rotating disc-rod-slider mechanism and a hinged four-way mechanism. This is a simple, reasonably priced and useful device for administrative agencies' workstations. An ordinary administrative worker can also operate it. This device is about the same size as a laptop or printer. It operates by clamping the seal, stamping constantly onto A4 pages. The stamping speed can also be changed by varying the shaft speed of the electric motor. It is convenient, but it also has the disadvantage of requiring someone to put the paper in and take it out. The box frame of this machine is made of plastic or wood. Some transmission components are made of steel. When this machine works, the force applied to it and the force caused by it are very small, so in general it is very simple and safe. Keywords: Gear transmission – rack, rotating disc mechanism – connecting rod – slider, four-hinged mechanism, stamping machine.

This article presents how to speculate, design and simulate a mechanical horse based on the point of view of the military man Khong Minh, a talented character in the work "Three Kingdoms" (author La Quan Trung). The behavior of this type of horse closely resembles that of a real horse. That is, it can walk, run, carry goods or people. It is made mainly of wood or steel. The authors speculated that Khong Minh placed a leaf spring in the belly of the mechanical horse. Soldiers just need to rotate so that the leaf spring twists, it will store energy in the form of potential energy. Then, it slowly unfolds, and the potential energy is converted into kinetic energy, transmitting motion to the mechanisms connected to the horse's legs. Finally, the mechanical horse lifted his leg and was able to walk. Despite such speculation, when recreating a mechanical horse, our team of authors used a battery-powered motor instead of leaf springs and gear transmissions as a pre-assembled transmission part in the belly of the mechanical horse. We design additional parts such as the head, tail, belly, legs, etc. to create a complete mechanical horse. The design goal of the author's mechanical horse is to clear people's doubts about the "wooden buffalo mechanical horse" in the literary work "Three Kingdoms". At the same time, this type of mechanical horse is also applied as an amusement ride for people in tourist areas and as a children's toy in the family.