in the legs 41 the spring 15 has a further mounting point 62 for mounting to the other compressor part as will be apparent in fig3 and from the earlier description in the preferred form this connection is to the piston rod 47 via a moulded plastic button 25 the spring 15 includes a pair of curved sections 63 64 of substantially constant radius of curvature which each pass around the cylinder mounting bar each of these curved sections extends over a length of approximately 360 u00b0 each section curves smoothly at both of its ends at the mounting bar transitions 65 66 they curve such that the lengths 67 68 of them at the cylinder mounting bar are radially aligned this sharper curve 65 66 is selected to maintain a substantially even stress distribution along the transition the alignment of the cylinder mounting ends 67 68 aligns then with the cylinder mounting bar the constant curvature sections 63 64 of the spring 15 may be rendered of any length in the example depicted they are each of approximately 360 u00b0 in length in the manner depicted in fig1 and 2 the mounting bar 43 of spring 15 is on the farther side thereof the central mounting point 62 is on the closer side thereof the constant curved sections 63 64 each curve smoothly at their lower ends to be radially aligned and continuous with one another across a diameter of the general circle of the spring at the mounting point 62 the alignment of this diameter is substantially perpendicular to the alignment of the.