A spring assembly for a roller blind, the assembly including a stationary end, a rotatable end and a spring arrangement located therebetween which is connected at a first end thereof to the stationary end and at a second end thereof to the rotatable end, wherein the rotatable end includes a rotatable body which is adapted to rotate relative to a fixed body about a rotational axis, and wherein the spring assembly further includes a locking pin coupled to the fixed body such that it has a locked configuration in which it engages a portion of the rotatable body and prevents rotation of the rotatable body relative to the fixed body and a free configuration in which rotation of the rotatable body relative to the fixed body is permitted.