Good design

The idea of re-opening is very good.

Collect comments and pay attention

The complete exploration process is very careful.
I think:
(1) The place where the thumb and index finger are pinched is not human-machine. General observation shows that the writing tool is made into a triangular section because it needs to be matched with the thumb and index finger pinching and the support of the middle finger. It can be seen that the middle finger does not play this role during the author's use, so the triangular section needs to be considered. Moreover, there is no depression in the pinch of thumb and forefinger, and man-machine is not considered according to the curved surface of fingertip, so it is estimated that the hand feeling is not good.
(2) Chalk is vulnerable. If the product is too closed and difficult to clean, it will be difficult to clean it if the chalk is broken inside, and there is no design that can be disassembled and cleaned;
(3) If the thickness design is to be suitable for writing and the chalk is pressed out, the structural design is estimated to be a difficult point. My idea is to make a way to use the tail spring to eject the sleeve, make a sleeve to cover the chalk, and lock the ban machine to control the ejection. Of course, this way of use can only be:
1. Take out chalk; The chalk is put into the sleeve and pushed in. At this time, the spring and locking mechanism work;
2. The chalk is bald, press the chalk head against the blackboard, pull the ban machine, release the sleeve controlled by the spring, pull the length back by hand, lock the ban machine back, and start using it.
I think it is very important not to ignore
speechless, ban machines are illegal

It is true that many teachers will have occupational diseases when using chalk for a long time, which can be improved. It is really great.

I can see that I have worked hard