Pressure gauge

A pressure gauge comprising:

• a first fastener, a second fastener, a rotation member, and a positioning module;
• the first fastener includes a first recess, a second recess, a central guide hole, and a guide portion;
• the central guide hole connects the first recess and the second recess;
• the guide portion is provided on an upper end of the central guide hole;
• the guide portion has a first spiral section and a second spiral section that are reversely opposite to each other;
• the first spiral section and the second spiral section construct a guide groove;
• the second fastener is mounted on a bottom of the first fastener;
• the second fastener has a first end portion and a second end portion;
• the second end portion is connected to the first end portion;
• the rotation member has a shaft;
• the shaft has a top end provided with a protruding rib and a pointer extending outward;
• the protruding rib and the pointer are opposite to each other horizontally and axially;
• the positioning module includes a positioning block and a elastic member;
• the positioning block has a center provided with an air hole penetrating the positioning block;
• the elastic member has a first end mounted on the air hole and a second end abutting a bottom of the rotation member;
• the first fastener is arranged above and connected with the second fastener;
• the positioning module is inserted into a bottom of the second fastener;
• the shaft extends through the central guide hole;
• the protruding rib and the pointer horizontally rest on the first spiral section and the second spiral section;
• the air hole is connected to an external air pressure source which introduces an air pressure into the elastic member so that the elastic member is expanded;
• and
• at the same time, the elastic member pushes the shaft upward so that the protruding rib and the pointer are rotated and moved upward along the guide groove defined by the first spiral section and the second spiral section, to precisely indicate visible air pressure values.