A compact clutch including a driven shaft on which the following are mounted: a gear wheel; a driving bush; a driven bush; a coil spring; a first collar with cam surfaces; and a second collar with cam surfaces. The gear wheel and the bushes are arranged axially next to each other; the gear wheel and the driving bush are constrained together in the circumferential direction; the spring surrounds externally the bushes; the first collar surrounds externally the spring; and the second collar surrounds externally the first collar. The gear wheel and the bushes are constrained to the driven shaft in the axial direction by means of two stop rings; and the driven bush is constrained to the driven shaft in the circumferential direction by means of at least one tongue.