Apparatus comprising a pump or compressor operated by a pull-cord wound
around a pulley (9), in which the pulley drives a shaft (11) which
drives the pump or compressor, and the pulley is recoiled by means of a retractor
type spring (32), torsion bar or elastic band. The retractor spring is mounted
not both co-planar and co-axial with the pulley. The principal may be applied to
reciprocating or rotary pumps or compressors, with compressible or incompressible fluid.
