An improved structure of pressure gauge includes a bottom case, a pressure measurement assembly, a rotating assembly, a fulcrum piece, a coil spring, a scale meter, and an outer case. The pressure measurement assembly is installed above the bottom case and the surface thereof is shaped with concentric circular waves. The rotating assembly includes a sleeve body and a central rod. A fulcrum piece is installed across between the sleeve body and the central rod. A plurality of through holes and a coil retaining base are provided on the fulcrum piece. One end of the coil spring is screwed onto the coil slot and the other end thereof is installed on the coil retaining base. The outer case is located in the outer area of the bottom case and the fulcrum piece. A transparent cover body is installed on top of the outer case.

An improved structure of pressure gauge includes a bottom case, a pressure measurement assembly, a rotating assembly, a fulcrum piece, a coil spring, a scale meter, and an outer case. The pressure measurement assembly is installed above the bottom case and the surface thereof is shaped with concentric circular waves. The rotating assembly includes a sleeve body and a central rod. A fulcrum piece is installed across between the sleeve body and the central rod. A plurality of through holes and a coil retaining base are provided on the fulcrum piece. One end of the coil spring is screwed onto the coil slot and the other end thereof is installed on the coil retaining base. The outer case is located in the outer area of the bottom case and the fulcrum piece. A transparent cover body is installed on top of the outer case.

A system and device for monitoring the content of a gas/liquid or gas only containment vessel such as a cylinder is provided. The disclosed apparatus is easily affixed to a standard gas cylinder and configured to monitor the pressure of the cylinder contents and activate a visual and/or audio alarm when the contents of the gas/liquid cylinder are no longer in a liquid or partially liquid state as well as activate another visual and/or audio alarm at a prescribed pressure when the contents of the cylinder are nearing depletion.

An improved air compressor includes a cylinder fitted with a piston body and an air storage container. The cylinder and the air storage container are detachably assembled to define an air chamber. A metal seat with a through hole is provided on top of the cylinder. A valve plug is spring-biased against the metal seat. The air storage container is provided with a pressure indicator, which includes a tube defining therein a first bore and a second bore, between which a tapered annular surface is formed. When the air pressure within the air storage container exceeds a predetermined pressure set for the air compressor, the pressure indicator allows excess air to flow into the first bore of the tube and sequentially pass through the tapered annular surface and an elongated opening to be released to the ambient environment, so that objects can be prevented from damages due to excessive inflations.

An improved air compressor includes a cylinder fitted with a piston body and an air storage container. The cylinder and the air storage container are detachably assembled to define an air chamber. A metal seat with a through hole is provided on top of the cylinder. A valve plug is spring-biased against the metal seat. The air storage container is provided with a pressure indicator, which includes a tube defining therein a first bore and a second bore, between which a tapered annular surface is formed. When the air pressure within the air storage container exceeds a predetermined pressure set for the air compressor, the pressure indicator allows excess air to flow into the first bore of the tube and sequentially pass through the tapered annular surface and an elongated opening to be released to the ambient environment, so that objects can be prevented from damages due to excessive inflations.

A battery powered device includes a battery and a motor controller that is coupled to the battery. A motor is operably coupled to the motor controller. The motor controller is configured to detect an amount of available power from the battery and engage the motor based on the amount of available power.

A battery powered device includes a battery and a motor controller that is coupled to the battery. A motor is operably coupled to the motor controller. The motor controller is configured to detect an amount of available power from the battery and engage the motor based on the amount of available power.

An indicating device, in particular a pressure gauge, including: a basic housing including a mechanism for driving a rotating needle indicator, movable relative to a dial, an interface housing attached to the basic housing, at least one rotary screen carried by the interface housing, for locating an operating area, of which the angular position can be adjusted about the axis of the needle, a protective cover removable attached to the interface housing and making it possible, when removed, to adjust the position of the rotary screen without separating the interface housing from the basic housing.

An optical reading device for a pointer instrument which has a pointer and a scale face or dial with different degrees of reflectance in each case, includes an illumination device for illuminating the scale face or dial and a plurality of light sensor elements which are arranged in a circular arc about the rotational axis of the pointer in order to detect the light of the illumination device reflected back by the scale face or dial, wherein the illumination device is configured to uniformly illuminate the scale face or dial and each light sensor element is configured with an isosceles triangle outline, where each light sensor element is offset with respect to one another by half of the base width in the circumferential direction of the circular arc.

A pressure gauge includes a hollow tube, a drive element, an anti-leak spring, a resilient element, and a cap. The hollow tube includes an accommodation chamber, a connector having a conduit, and a display unit. The drive element includes a protection unit, a first open segment, a second distal segment, a receiving portion, a hollow extension, and a protrusion. An anti-leak spring is received in the hollow extension of the drive element and abuts against the protrusion and the protection unit. The resilient element is received in the receiving portion. The cap includes a seat, a push bolt, and multiple passages. The accommodation chamber has a first fixing section and a second fixing section, a diameter of which is different from that of the first fixing section. The hollow tube further includes a tilted surround section and at least one discharge orifice.