An air compressor includes an air storage unit defining a first chamber and a cylinder containing a piston body. The top wall of the cylinder is formed with a tubular projection defining a bore to serve as a second pressure chamber. When the piston head of the piston body is almost in contact with the top wall of the cylinder, part of the compressed air can enter the second pressure chamber, so that the piston body can conduct reciprocation motion more smoothly. Furthermore, the cylinder has an open bottom that is divided into two halves according to a central vertical line of the cylinder, wherein one half of the open bottom is horizontal while the other half of the open bottom is slanted. When the piston body is at BDC, the piston head will be entirely within the cylinder and thus keep gas-tight with the cylinder.

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 inflator cap comprising: an outer cover; an anti-corrosion lining formed in or inside the outer cover; and a magnetic member formed on, in or inside the outer cover, whereby the magnetic member of the inflator cap, once unscrewed from the inflator, will be magnetically attractable on a ferromagnetic object to prevent its loss; or whereby the anti-corrosion lining will preclude a direct contact between the outer cover of the inflator cap and a valve stem of the inflator to prevent from sticking of the oxide of the outer cover once oxidized on the valve stem of the inflator, thereby smoothly unscrewing the cap from the inflator.

A floor pump includes a base, a first cylinder, a second cylinder, an air tube, a handle and an air release device. The first cylinder and the air tube unidirectionally communicate with the base. The second cylinder is movably connected within the first cylinder and has a first piston. The air tube is disposed in the second cylinder and has a second piston. The handle is connected to the second cylinder. The air release device is disposed in the handle and includes a switcher and an air release valve assembly configured to be pressed by the switcher to move relative to a through hole of the handle to cause the second cylinder selectively communicates with the outside of the floor pump.

A linear compressor includes a cylinder that defines a compression space of a refrigerant and has a cylindrical shape, and a piston disposed in the cylinder and reciprocating along an axis of the cylinder. The cylinder includes a supply port radially passing through the cylinder, and a recess formed on an inner circumferential surface of the cylinder and communicating with the supply port. The supply port includes a first supply port and a second supply port disposed in a rear of the first supply port, and the recess includes a first recess and a second recess disposed in a rear of the first recess. The first recess and the second recess are formed in different shapes.

A variable-pressure air pump includes a first cylinder with a first chamber and a second cylinder with a second chamber movably connected with one another. The second chamber fluidly communicable with the outside of the variable-pressure air pump selectively. A discharge device includes a connecting member and a switch movably connected with one another. The connecting member defines at least one discharge hole fluidly connecting with the second chamber. The switch has at least one flow guide portion and at least one blocking portion. The switch is movable between a first position in which the at least one flow guide portion is adjacent and opens to the at least one discharge hole and a second position in which the at least one blocking portion is adjacent to and blocks the at least one discharge hole.

An improved air compressor generally includes a cylinder fitted with a piston body, a main frame for mounting a motor, and an air storage container. The cylinder defines at its top wall a plurality of exit holes, which are separated by a plurality of blocking walls and regulated by a control mechanism. When the compressed air is produced in the cylinder causing the control mechanism to open the exit holes, the instantaneous high-pressure air that flows through the exit holes can be restrained by the blocking walls to prevent the air from interfering with operation of the control mechanism, so that the piston body can conduct reciprocating motion more smoothly and thus the performance of the air compressor can be increased.

An improved air compressor includes a cylinder fitted with a piston body, a main frame for mounting a motor, and an air storage container. The cylinder defines at its top wall a plurality of exit holes, which are separated by a plurality of blocking walls and regulated by a resilient sheet having a plurality of branches corresponding to the exit holes. When the compressed air produced in the cylinder pushes the resilient sheet up to open the exit holes, the instantaneous high-pressure air that flows through the exit holes can be restrained by the air blocking walls to prevent the air from interfering with movements of the branches of the resilient sheet, so that the piston body can conduct reciprocating motion more smoothly and thus the performance of the air compressor can be increased.

A piston-cylinder unit including a piston that is fluid pressure supported and movable in a linear manner in a cylinder, wherein the cylinder, a face wall of the piston and a face wall of the cylinder define a compression cavity which is at a minimum size in a portion of a top dead center of the piston, wherein the compression cavity is connected in a fluid transferring manner with a bearing gap which is formed between a cylinder inner circumferential wall and a piston outer circumferential wall, wherein a plurality of fluid outlet nozzles are arranged in at least one cross-sectional plane of the cylinder in the cylinder inner circumferential wall along a circumference, which fluid outlet nozzles open into the bearing gap and are connected with a supply conduit for a pressurized fluid.

A portable inflation device having a pump, a control device, a user interface, and an inflation indicator. The pump includes an elongated hose with an inflation nozzle. The control device controls operation of the pump and is configured to sense a current pressure of an object, calculate the estimated remaining time to inflate the object to a target pressure, and display the remaining time using the inflation indicator. The user interface is configured to allow a user to enter the target pressure into the control device.