Piston for compressors including a restrictor to prevent the piston from rotating

A piston for use in a compressor that compresses gas containing lubricating oil, wherein the compressor includes a housing having a crank chamber and a cylinder bore for accommodating the piston, wherein the housing has an inner surface for defining the crank chamber, wherein a driving body is located in the crank chamber and is supported on a drive shaft, and wherein the driving body is operably connected to the piston by a connecting joint to convert the rotation of the drive shaft to reciprocation of the piston between a top dead center position and a bottom dead center position, the piston comprising:

• a head for disposition in the cylinder bore reciprocable therein for compressing gas supplied to the cylinder bore;
• a skirt projecting from the head for location within the crank chamber for connection to the driving body;
• a restrictor provided on the free end of said skirt and having a peripheral surface for slidably contacting the inner surface of the housing to prevent the piston from rotating in the cylinder bore, the restrictor having an end face;
• and
• a sloping surface extending along the perimeter of said end face of the restrictor joining said end face to said peripheral surface, wherein said sloping surface guides the oil in the crank chamber toward the connecting joint when the piston is moved from the top dead center position to the bottom dead center position.

A compressor for compressing gas containing lubricating oil, wherein the compressor includes a housing having a crank chamber and a cylinder bore, wherein the housing has an inner surface for defining the crank chamber, a driving body located in the crank chamber and supported on a drive shaft, and a piston accommodated in the cylinder bore and operably connected to the driving body by a connecting joint, wherein the driving body converts the rotation of the drive shaft to reciprocation of the piston between a top dead center position and a bottom dead center position, the compressor further comprising:

• a head on the piston for compressing gas supplied to the cylinder bore;
• a skirt projecting from said piston head toward said crank chamber connected to the driving body by said connecting joint;
• a restrictor provided on the free end of said skirt and having a peripheral surface slidably contacting the inner surface of the housing to prevent the piston from rotating in the cylinder bore, the restrictor having an end face;
• and
• a sloping surface extending along the perimeter of said end face of the restrictor joining said end face to said peripheral surface, wherein said sloping surface guides the oil in the crank chamber toward the connecting joint when the piston is moved from the top dead center position to the bottom dead center position.