ANTIQUE CHINESE COIN (PA KUA SCRIPT) I CAN'T FIND WHAT IT IS HELP

Hello, I am from China but I have to say that the characters in this coin are so confusing. On the top may be a character 大,it means'big', and on the right hand and left hand may be two characters,
form a word乾坤, it means 'the world', but I can't
racognize other characters and I don't know what kind of coin it is.
 

 That first picture is a 'miniature' and is not enlargeable. 

Link to it amended: https://en.numista.com/forum/images/62c22c1ec91bf.jpg 

Both cropped: 

 Maybe it is a token. What is the diameter? 

It is a Chinese folk money called 花钱(huaqian)/厌胜钱(yanshengqian)/压胜钱(yashengqian), ancient people didn't used it to buy things, but believed that it can protect evil spirits. Now I recognize that its obverse shows a Eight diagrams, which is called 八卦(bagua) in Chinese, a common pattern in  Chinese huaqian, means that all the things in the world are connected. But I still don't know others characters' meaning in the reverse.

Is the coin in the data base of this web Page?

The best source of writings on charms is here, but I didn't find yours

Well … you might try …