Guiding mechanism for reciprocating piston of piston type compressor

A piston guiding mechanism for use in a piston-type compressor of the type including a housing containing a cylinder block where the cylinder block has at least one bore in which a reciprocative piston is disposed, the piston having a central portion and a peripheral surface, whereby a refrigerant gas containing lubricating oil can be drawn into said bore from outside the compressor to be compressed within said bore and discharged from the compressor in response to reciprocating motion of said piston, said piston guiding mechanism comprising:

• an oil transfer section extending radially from said central portion to said peripheral surface of said piston and including in said piston a longitudinally extending hollow section and a cut-away portion, the cut-away portion constituting a passage communicating with said hollow section;
• said oil transfer section being movable between points in said housing and said bore during reciprocating motion of said piston for transferring said lubricant oil contained in said refrigerant gas from said point in the housing to said bore;
• a radially extending projection formed on said peripheral surface of said piston and located adjacent an end of said hollow section and cut-away portion;
• and
• a guiding surface formed inside said housing for guiding said projection to slide smoothly along said guiding surface when said piston reciprocates.