Knowledge expansion:
Pencil sharpener is a tool for sharpening pencils. Pencil sharpener can be divided into ordinary pencil sharpener and electric pencil sharpener. Ordinary pencil sharpener generally consists of three parts: blade, scabbard and waste box, which is cheap. Electric pencil sharpener is more convenient to use, but the price is higher than that of ordinary pencil sharpener.
Origin:
Pencil Sharpener was patented by Eric Gauss and Daniel LaCamille of France on 1906. Pencil sharpener can be divided into (ordinary pencil sharpener) and (electric pencil sharpener). Ordinary pencil sharpener consists of three parts: blade, scabbard and waste box. The blade is fixed on the scabbard with screws. The scabbard is mostly rectangular plastic with holes to support the blade.
The scabbard is fixed in the waste box, which can be round, square and various forms. It also needs the same hole as the scabbard for the pencil to enter. Most garbage bins are designed to be detachable to facilitate the removal of garbage. An electric pencil sharpener aims at solving the problems of automatically sharpening pencils and storing pencil foam.
It is mainly composed of an upper pencil box, a cutter, a push rod, a supporting partition, a tool rest, a pressure plate, a pressure sensor, a transmission gear, a motor and a lower box. It is characterized in that the middle part of the inner side of the upper pencil case is fixedly installed on the whole supporting partition, and the middle part of the supporting partition is machined with a mechanical method to facilitate the push rod and the cutter to pass through.
The cutter is connected with a transmission gear through a tool rest, the transmission gear is connected with a motor through a transmission shaft, the front end of a push rod is nested in the cutter, the rear end of the push rod is fixedly connected with the front side of a pressure plate, the rear end of the pressure plate is connected with a pressure sensor, the pressure sensor is connected with a power supply through a wire, and is connected in series with a power supply, a switch and a motor to form a closed loop, and the whole stationery box is fixedly placed on the left side of the lower box body.
Working principle:
When you turn the pen by hand, you use the friction between the hand and the pen holder. When the pencil rotates on the inner wall of the rotating hole, there is indeed friction, because, first of all, there is contact between them and there is a certain rough surface-the friction coefficient is not zero, so the friction is effectively used.
What really cuts the wood from the pencil body is the powerful function between the pen and the blade. Sharp blade, high pressure, can cut wood from the pen. It is related to pressure, not friction.