Piston rod for oil-less air compressor

Abstract

A piston rod for oil-less air compressor mainly includes a piston head having a centered fixing hole and a plurality of through holes spaced around the fixing hole, and a disk-like check valve screwed to the fixing hole of the piston head without leaving any recess or gap between the check valve and the piston head. When the piston rod is in an upward compress stroke, the check valve tightly bears against the piston head to fully close the through holes on the piston head and keeps the piston head in a completely plane surface without any recess or gaps to form any residual air pressure there at; and when the piston rod is in a downward return stroke, the check valve is in a floating position to open the through holes on the piston head for air to enter into an air cylinder for compression later.

1 . A piston rod for oil-less air compressor, comprising a lower end connected to a motor of said oil-less air compressor, and an upper piston head reciprocatingly moved in an air cylinder of said air compressor, so that air is admitted into said air compressor, compressed, and discharged into an externally connected air tank for storage; said piston rod being characterized in that said piston head has a completely plane top surface, on which a centered fixing hole and a plurality of through holes spaced around said fixing hole are provided, and that a disk-like check valve having a centered through hole is loosely mounted to said piston head by extending a screw through said centered through hole of said check valve into said centered fixing hole of said piston head; whereby when said piston head is in an upward compress stroke or a downward return stroke, said check valve tightly bears against said piston head to close said through holes on said piston head or is in a floating position to open said through holes on said piston head, respectively, to facilitate compression of air in said air cylinder and prevent forming of any residual air pressure at said piston head.