Abstract: A compressor comprising: a cylinder crankcase (10) defining a compression chamber (13) housing a reciprocating piston (22); an actuating means (40) coupled to the piston (22); and a resonant spring means (50) having a first and a second diametrical end segment (50a, 50b) respectively affixed to the actuating means (40) by a first securing means (MF1) and to the cylinder crankcase (10) by a second securing means (MF2), the latter comprising: a base vise jaw (60, 60?) affixed to the second diametrical end segment (50b); a top vise jaw (70, 70?) mounted between opposite portions of the cylinder crankcase (10) and seated, pressed and locked against the base vise jaw (60, 60?), in a condition in which the axes of the end diametrical segments (50a, 50b) intercept the axis of the compression chamber (13) and in which the piston (22) has a predetermined axial position in the compression chamber (13).