Abstract: A hinge has a pivot assembly and a holding assembly. The pivot assembly has a securing panel, a connecting seat, a pivot shaft, and two positioning sets. Each of the positioning sets has a positioning ball and a silencing positioning element filled with lubricating grease. The holding assembly has two holding sheets holding the pivot shaft. With the holding sheets and the pivot shaft abutting each other with tooth or embossed surfaces, friction between the holding sheets and the pivot shaft is increased. Thus, the pivot shaft and the holding sheets do not pivot relative to each other easily. The lubricating grease in the silencing positioning elements can be smeared on the positioning balls, such that the positioning balls can smoothly roll on the pivot shaft without abrasion and no noise will occur.

Abstract: A hinge has a pivot assembly and a holding assembly. The pivot assembly has a securing panel, a connecting seat, a pivot shaft, and two positioning sets. Each of the positioning sets has a positioning ball and a silencing positioning element filled with lubricating grease. The holding assembly has two holding sheets holding the pivot shaft. With the holding sheets and the pivot shaft abutting each other with tooth or embossed surfaces, friction between the holding sheets and the pivot shaft is increased. Thus, the pivot shaft and the holding sheets do not pivot relative to each other easily. The lubricating grease in the silencing positioning elements can be smeared on the positioning balls, such that the positioning balls can smoothly roll on the pivot shaft without abrasion and no noise will occur.

Abstract: A nozzle for paint spray guns, including a tubular nozzle body having a conical nozzle tip at one end and an outer thread at an opposite end, a first collar tightly mounted around the tubular nozzle body and having a plurality of axial through holes; and, a second collar tightly mounted around the tubular nozzle body between the first collar and the outer thread of the tubular nozzle body and having a plurality of axial through holes which are not in longitudinal alignment with the through holes of the first collar and through which compressed currents of air are driven toward the through holes of the first collar, after a mixing process at the annular space defined between the first collar and the second collar, to mix with the output spray of paint into a good atomization of paint.

Abstract: An improved flow regulating mechanism for paint spray guns includes a spray gun body, a flow regulating mechanism and a nozzle. The flow regulating mechanism is disposed in a secondary air duct of the spray gun body and comprises a regulating rod, a regulating knob, a fixed regulating ring and a movable regulating ring. The regulating rings are each provided with a central through hole and a plurality of spaced apart air vents running parallel to the through hole. The regulating rod is screwably disposed in the secondary air duct by the regulating knob. The movable regulating ring and the fixed regulating ring are disposed in the secondary air duct in sequence such that an air chamber is defined between the regulating rings. The size of the air chamber can be adjusted by the regulating rod. High-pressure air flowing via the secondary air duct of the spray gun body may be reduced in pressure and regulated to prevent sputtering of paint due to excessively high pressure.