An air compressor, which comprises:
- a main frame;
- a cylinder fitted with a piston body and provided at the main frame;
- and
- a motor mounted to the main frame, the motor capable of driving the piston body to conduct reciprocating motion within the cylinder for producing compressed air;
- wherein the cylinder has an open bottom, through which the piston body is fitted into the cylinder, and a top wall opposite to the open bottom, the top wall being not fully closed, wherein the cylinder is provided with a first flange at its surrounding wall, near its top wall, the first flange being provided with two opposite holding portions each defining a first recess;
- an air storage container has an open bottom and a closed top and defines therein an inner space terminating at the open bottom, the air storage container being provided at its open bottom with a second flange that is provided with two opposite holding portions each defining a second recess;
- whereby the air storage container is capable of being fitted over the cylinder and rotated about the cylinder to allow the second flange of the air storage container to slide in the first recesses of the cylinder and allow the first flange of the cylinder to slide in the second recess of the air storage container, so that the air storage container is detachably mounted to the cylinder, thereby sealing the cylinder and defining an air chamber therebetween;
- further wherein the air storage container is provided with at least two outlets, on of which is connected with a pressure indicator and another of which is connected with a hose provided with an air nozzle, wherein the pressure indicator includes:
- a tube has a first segment and a second segment, the second segment being joined to one outlet of the air storage container and defining therein a second bore, the first segment being formed integrally with the second segment and having an open end and defining therein a first bore that communicates with the second bore and terminates at its open end, the first bore having a diameter greater than the second bore, a tapered annular surface formed between an inner surface of the first segment, which defines the first bore, and an inner surface of the second segment, which defines the second bore, the first segment defining at its surrounding wall an elongated opening extending from the tapered annular surface to its open end;
- a stationary transparent plate provided with a marking line and detachably fixed onto the tube;
- a slider including a hollow cylindrical body having a closed end and an open end and defining therein an inner space that terminates at the open end, the cylindrical body being provided with a first central tube that extends from an inner surface of its closed end and extends through its inner space, the slider further including a panel that is joined to the hollow cylindrical body through a neck portion such that the panel is parallel to the tube, the hollow cylindrical body being fitted into the tube and the neck portion being inserted through the elongated opening, so that the panel is capable of moving together with the hollow cylindrical body, the panel being provided with a layer of pressure-indicating scale at its outer surface;
- a coiled compression spring fitted into the inner space of the slider, around the first central tube;
- and
- a cap has an inner base and a second central tube extending from the inner base, the second central tube defining therein a central hole, the diameter of the central hole of the second central tube of the cap being greater than the external diameter of the first central tube of the slider, the external diameter of the second central tube of the cap being less than the internal diameter of the coiled compression spring;
- whereby the compressed air contained in the air storage container can flow into the inner space of the second segment of the tube via the outlet and thus force the slider to move along the second bore and the first bore towards the open end of the first segment of the tube, so that the position of the marking line of the stationary transparent plate relative to the pressure-indicating scale on the panel of the slider can reveal the pressure of the compressed air within the air storage container, and furthermore, when the compressed air exceeds a predetermined pressure set for the air compressor, the compressed air can be released into the ambient environment through the elongated opening.