Abstract: An improved gearless pressure gauge comprises a sensing member, an elastic member flexibly mounted with respect with the sensing member, a seat member carrying a helix capable of moving with the elastic member, and a rotary shaft including a fixed lateral pin laying on the helix which can be rotatably driven thereby responding to the movement of the sensing member under pressure, which in turn imparts through the elastic member and forces the helix to move upwardly, a pointer carried by the rotary shaft thus can give a pressure reading, the rotary shaft can return to its initial position when the pressure on the sensing member is removed by the restoring force of a spiral spring.

Abstract: A pressure gauge comprising a diaphragm, a cylinder seat, and a driving helix movable up or down to constitute the operating elements. A rotary shaft with a pin fixed thereon rotates clockwise or counterclockwise responsive to the movement of the diaphragm. The rotary shaft will return to its initial position when the pressure on the diaphragm is removed by the restoring force of a helical spring.